Bradley et al. (2011) Level: III-2 Quality: 15/26 Cohort study 234 patients in the wireless group 106 patients in the catheter group Adults 5/234 procedures (2.1%) 2 early detachments 3 endoscopic removals due to severe discomfort 1/106 procedures (0.9%) 1 catheter intolerance 2.26 [0.27, 19.15] Hakanson et al. (2009) Level: III-2 Quality: 14/26 Case-control study with simultaneous recording 53 volunteers and 55 patients Adults 13/108 procedures (12.0%) 5 attachment failures 4 early detachments 3 immediate detachments 1 recording failure 2/108 procedures (1.9%) 1 sensor displacement in the stomach 1 catheter intolerance 6.50 [1.5, 28.12] Croffie et al. (2007) Level: II Quality:14.5/26 Randomised controlled trial 30 patients in wireless + catheter group, 18 patients in wireless group and 18 in catheter group Children 2/48 procedures (4.2%) 1 recording failure 1 early detachment 2/48 procedures (4.2%) 1 recording failure 1 catheter intolerance 1.00 [0.15, 6.81]
Table Diagnostic accuracy of catheter-free monitoring compared to clinical diagnosis for diagnosing GORD in adults Study Evidence level and quality Population Index test & cut-off point Reference standard & cut-off point Sensitivity % [95%CI] Specificity % [95%CI] PPV % [95%CI] NPV % [95%CI] LR+ LR– Accuracy [95%CI] Wenner, Johansson et al. (2007), Wenner et al. (2008) Diagnostic case-control study Level: III-3 Quality: Patient selection: Index test: ? Reference standard: Flow and timing: ? CX P3 119 subjects (64 patients and 55 controls) Bravo pH monitoring Time under pH 4 >1.9, 2.2, 2.3, 3.2, 3.6 and 4.4 Clinical diagnosis 1.9: 88% 2.2: 86% 2.3: 83% 3.2: 68% 3.6: 64% 4.4: 59% 1.9: 75% 2.2: 80% 2.3: 80% 3.2: 85% 3.6: 91% 4.4: 96% - - 1.9: 3.52 2.2: 4.30 2.3: 4.15 3.2: 4.53 3.6: 7.11 4.4: 14.75 1.9: 0.16 2.2: 0.18 2.3: 0.21 3.2: 0.38 3.6: 0.40 4.4: 0.43 - Bansal et al. (2009) Diagnostic case-control study Level: III-3 Quality: Patient selection: Index test: ? Reference standard: Flow and timing:? CX P2 56 subjects (40 patients and 16 controls) Bravo pH monitoring Time under pH 4 >4.4% for the proximal location (6 cm above GOJ), and time under pH 4 >10.6% for the distal location (1 cm above GOJ) Clinical diagnosis (no symptoms of reflux in control population) Proximal: 67% Distal: 60% Proximal: 66% Distal: 88% - - - - -
Appendix Studies included in the review Study profiles of included studies on safety Study setting Study design / Quality appraisal Study population Inclusion criteria / Exclusion criteria Diagnostic tests Safety outcomes assessed Agrawal, Akerman & Rich () Rhode Island Hospital, Warren Alpert Medical School of Brown University, Providence, Rhode Island, USA Case report Level: NA 1 patient 45 year old female Indication: Persistent heartburn despite maximal acid-suppressive therapy Inclusion: NA Exclusion: NA Index test: System: Bravo™ wireless capsule system Insertion: not stated Placement: 6 cm above the SCJ Duration: not stated Mild epigastric pain Severe retrosternal chest discomfort Ahlawat et al. () Division of Gastroenterology, Department of Medicine, Georgetown University Hospital, Washington, DC, USA Retrospective case series Level: IV Quality: Q1 CX (no comparator) P2 90 patients 48 males and 42 females Age range: 18–80 years Indications: Being to the conventional naso-oesophageal pH catheter placement or had normal 24-hour oesophageal pH monitoring despite symptoms Inclusion: Not stated Exclusion: Patients with bleeding diathesis, strictures, severe oesophagitis, varices, obstructions, pacemakers, implantable cardiac defibrillators, and surgical manipulations of the upper GI tract Index test: System: Bravo™ wireless capsule system Insertion: transorally Placement: 6 cm proximal to the SCJ Duration: 48 hours Comparator: NA Chest pain Foreign-body sensation Andrews et al. () Division of Gastroenterology, University of Calgary, Canada Dual centre, randomised, trial Level: II 86 patients (40 in Calgary and 46 in Edmonton) 61 females, 25 males Age range 18–75 years Inclusion: Patients aged 18–75 years referred for ambulatory pH monitoring between August 2008 and August 2009 Exclusion: Index test: System: activated and calibrated Bravo™ wireless capsule system, Medtronic Inc., Minneapolis, MN Insertion: transorally Manometry discomfort (nasal, throat, chest, overall) pH placement discomfort (nasal, blinded
Bradley et al. () Division of Gastroenterology and Hepatology, Mayo Clinic, Scottsdale, Arizona, USA Cohort study Level: III-2 Quality: 15/26 CX P2 341 patients (248 patients underwent Bravo monitoring) 62% females in the wireless group, 72% females in the catheter group Mean age: 58 years in wireless group, 57 years in catheter group Inclusion: Outpatients undergoing ambulatory between October 2006 and October 2008 Exclusion: Known history of oesophageal strictures, obstructions or surgical manipulations of the upper GI tract (e.g. anti-reflux surgery or oesophagectomy) Index test: System: Bravo™ wireless capsule system Insertion: transorally Placement: 6 cm above the SCJ or 5 cm above the upper border of the LOS Duration: 48 hours Comparator (MII-pH): System: Sandhill Scientific Inc., Highland Ranch, USA Insertion: transnasally Placement: proximal channel 5 cm above upper border of the LOS Duration: 24 hours Comparator (pH-metry): System: Alpine Biomed, Corp, Fountain Valley, USA Insertion: transnasally Placement: 5 cm above the upper border of the LOS Duration: 24 hours Chest discomfort Foreign-body sensation Chest and abdominal pain Difficulty swallowing Painful swallowing Eating and drinking Nausea and vomiting Cabrera et al. () Division of Pediatric Gastroenterology, Hepatology and Nutrition, Indiana University School of Medicine, Indianapolis, Prospective case series Level: IV Quality: Q1 CX (no comparator) 289 patients (At least 1 day of data was obtained in 278 patients; 2 days were obtained in 274 patients) 144 females, 145 males Age: range 4–22 years Indications: Inclusion: Children who are at least 4 years of age and weigh at least 30 lb Exclusion: Children with a history of oesophageal surgery, a documented anatomic abnormality, or a history of coagulopathy or a bleeding diathesis Index test: System: Bravo™ wireless capsule system Insertion: transorally Placement: at 87% of the distance from the incisors to the Z line Duration: 48 hours Comparator: NA Oesophageal mucosa tear
Fiterman Center for Digestive Diseases, Mayo Clinic, Rochester, Minnesota, USA Level: IV Quality: Q2 CX (no comparator) P2 Exclusion: Not stated Insertion: NS Placement: 6 cm above the SCJ Duration: 48 hours Comparator: NA dislodgement in the pyriform sinus Francis, DO et al. () Division of Gastroenterology, Hepatology and Nutrition, Vanderbilt University Medical Center, Nashville, Tennessee, USA Randomised, blinded controlled trial Level: II Quality: 16/26 C1 P2 22 patients were included (13 males, 9 females) Indications: Cough, hoarseness, globus, heartburn, regurgitation Inclusion: Patients >18 years of age, scheduled for planned oesophagogastroduodenoscopy and wireless pH monitoring for physiologic assessment of oesophageal acid exposure for typical GORD symptoms or for extraoesophageal reflux (EER) symptoms Exclusion: History of upper oesophageal surgery, bleeding dyscrasia, recent cerebrovascular accident or transient ischemic attack, recent (<6 months) GI haemorrhage, oesophageal varices or significant medical illness, current pregnancy Index test: System: Bravo™ wireless capsule system Insertion: transorally Placement: 16 cm above the SCJ Duration: 48 hours Comparator: No monitoring (a sham capsule placement) Chest pain (adj OR) Odynophagia (adj OR) Dysphagia (adj OR) Garrean et al. () Division of Gastroenterology, Northwestern University Freiberg School of Medicine, Chicago, Illinois, USA Case series (prospective?) Level: IV Quality: Q2 CX (no comparator) 60 patients (22 males and 38 females) Age: 19–80 years 40 patients had complete 4-day data acquisition Indications: acid reflux symptoms, chest pain, laryngeal symptoms that were poorly Inclusion: Not stated Exclusion: Not stated Index test: System: Bravo™ wireless capsule system Insertion: NS Placement: 6 cm above the SCJ Comparator: NA Back pain Globus sensation Chest pain
P2 responsive to twice-daily PPI therapy for a minimum of 6 weeks Gillies et al. () Departments of Upper Gastrointestinal Surgery and Gastrointestinal Physiology, Royal Berkshire hospital, Reading, UK Non-randomised controlled trial Level: III-2 Quality: 13.5/26 CX P2 185 patients, but 200 oesophageal pH studies 104 males, 81 females Mean age: Catheter group: 46 years (range Bravo group: 45 years (range 13–75) Indication: Symptoms suggestive of GORD or documenting the outcome of laparoscopic anti-reflux surgery Inclusion: See indication Exclusion: No specific exclusion criteria exist Index test: System: Bravo™ wireless capsule system Insertion: transorally Placement: 6 cm proximal to the SCJ Duration: 48 hours Comparator: System: Medtronic Insertion: transnasally Placement: 5 cm above the proximal border of the LOS Duration: 24 hours Overall discomfort (during insertion and monitoring) Nasal discomfort Throat discomfort Oesophageal discomfort Interference with daily activities Eating Sleeping Work attendance Grigolon et al. () Gastroenterology, Department of Medical Sciences, University of Milan, Milan, Italy controlled trial Level: III-1 Quality: 13.5/26 CX P2 133 patients Catheter group: 78 patients, 46% males, aged 53 ± 2 years Bravo group: 55 patients, 45% males, aged 44 ± 3 years) Indication: Suspected GORD, consecutively referred for oesophageal pH monitoring Inclusion: See indication Exclusion: Previous GI surgery (excluding cholecystectomy and appendectomy) and known or suspected stricture of the GI tract Index test: System: Bravo™ wireless capsule system Insertion: transorally Placement: 6 cm above the SCJ Duration: 48 hours Comparator: System: Slimline mod 901P3001, Medtronic, Denmark Insertion: transnasally Placement: 6 cm above the point of sudden change in pH from acid to neutral as detected by means of continuous rapid withdrawal from the stomach, or 5 cm above the upper margin of the LOS Discomfort at placement Overall discomfort Chest discomfort Eating and drinking Interference with daily activities
University Feinberg School of Medicine, Chicago, Illinois, USA Level: IV Quality: Q2 CX (no comparator) P2 Median age: 52 years Indications: Chest pain, refractory heartburn, laryngeal symptoms Exclusion: Not stated Placement: 6 cm above the endoscopically determined SCJ Duration: 4 days Comparator: NA Hochman and Favaloro-Sabatier () Children’s Center for Digestive Health Care, Atlanta, Georgia, USA Retrospective case series Level: IV Quality: Q2 CX (no comparator) P2 44 patients (children) 27 males, 17 females Mean age: 11.8 years (range 6–19) Inclusion: Not stated Exclusion: Not stated Index test: System: Bravo™ wireless capsule system Insertion: not stated Placement: 6 cm above the proximal border of the LOS Duration: 48 hours Comparator: NA Patient discomfort Hogan et al. () Gastrointestinal Associates, Jackson, Mississippi, USA Case report (letter to the editor) Level: NA 1 patient 72 year old male Indication: Symptoms of gastro-oesophageal reflux Inclusion: NA Exclusion: NA Index test: System: Bravo™ wireless capsule system Insertion: not stated Placement: not stated Duration: not stated 2-year retention of the capsule in a giant colonic diverticulum Karamanolis et al. () 2nd Department of Internal Medicine, Propaedeutic Attikon University General Hospital, Athens, Greece Case series (prospective?) Level: IV Quality: Q1 CX (no comparator) P2 32 patients 18 males, 14 females Mean age: 45.3 ± 12.5 years Indications: Three episodes of non-cardiac chest pain per week Inclusion: Patients with at least three episodes of chest pain per week and normal oesophageal manometry (in order to exclude the presence of any oesophageal motility disorder) Exclusion: Patients that were using aspirin or NSAIDs, a history of upper GI surgery, gastric or duodenal ulcer, connective Index test: System: Bravo™ wireless capsule system Insertion: transorally Placement: 6 cm proximal to the SCJ Duration: 48 hours Comparator: NA Throat pain Back pain Globus sensation
tissue disease, or severe liver, lung, renal or haematological disease Kramer & Chokhavatia () Department of Medicine, the Mount Sinai Medical Center, New York, New York, USA Case report Level: NA 1 patient 44 year old male Indication: History of GORD symptoms, to anti-reflux therapy Inclusion: NA Exclusion: NA Index test: System: Bravo™ wireless capsule system Insertion: not stated Placement: 6 cm above the GOJ Comparator: NA Capsule dislodging into the pyriform sinus Lacy, Chehade & Crowell () Section of Gastroenterology and Hepatology, Medical Center, Lebanon, New Hampshire, USA Case series Level: IV Quality: Q1 CX (no comparator) P2 358 patients (257 females, 101 males) Mean age: 51 ±14 years Predominantly (97%) Caucasian Indications: Symptoms thought secondary to GORD Inclusion: Not stated Exclusion: Not stated Index test: System: Bravo™ wireless capsule system Insertion: transorally Placement: 6 cm above the GOJ or 5 cm above the upper border of the LOS Duration: 48 hours Comparator: NA Chest discomfort Lee et al. () Department of Internal Medicine, Department of Emergency Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan Prospective case series Level: IV Quality: Q3 CX (no comparator) P2 40 patients (27 males and 13 females) Age: range 28–83 years Indications: Typical heartburn with unsatisfactory response to therapy (15), erosive oesophagitis and undergoing preoperative evaluation (25) Inclusion: Not stated Exclusion: Not stated Index test: System: Bravo™ wireless capsule system Insertion: transorally Placement: 6 cm above the SCJ Duration: 48 hours Comparator: NA Retrosternal discomfort Mucosal lesion Foreign-body sensation Marchese et al. () Prospective case 40 patients (36 patients had successful oesophageal placement of Inclusion: Index test: Mild discomfort Severe chest pain
Digestive Endoscopy Unit, Agostino Gemelli University Hospital, Catholic University of Rome, Rome, Italy series Level: IV Quality: Q1 CX (no comparator) P2 the capsule) 23 males, 17 females Mean age: 42.5 years Indications: Reflux symptoms that were refractory to PPI therapy Patients with reflux symptoms refractory to PPI therapy who had normal or equivocal endoscopic findings Exclusion: Patients with oesophageal varices, previous GI surgery, known coagulopathy or bleeding diathesis, cardiac pacemakers, defibrillators or other electromedical devices, significant comorbidity, pregnant women and patients <18 years of age System: Bravo™ wireless capsule system Insertion: transnasally Placement: 5 cm above the upper margin of the LOS Duration: 24 or 48 hours Comparator: NA (Endoscopic removal of the capsule) Epistaxis Pharyngeal irritation Nusrat, Roy & Bielefeldt () University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA Retrospective case series Level: IV Quality: Q1 CX (no comparator) P2 356 patients (65% females) Mean age: 49.9 ± 0.8 years Indications: Evaluations of GORD, recurrent or persistent symptoms after fundoplication, chest pain, unexplained cough or other atypical symptoms Inclusion: Not stated Exclusion: Patients with pacemakers, implanted cardiac defibrillators, known oesophageal varices, bleeding disorders or ongoing anticoagulation Index test: System: Bravo™ wireless capsule system Insertion: not stated Placement: 6 cm above the endoscopically localised SCJ or 5 cm above the manometrically determined upper border of the LOS Duration: 48 hours Comparator: NA No significant adverse effects during the study
Pandolfino et al. () Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA Cohort study Level: III-2 Quality: 11.5/26 CX P3 44 controls (13 males, 31 females, aged 23–53 years) 41 patients (26 males, 15 females, aged 32–72 years) Inclusion: Not stated Exclusion: Controls: abdominal symptoms, use of antacids or antisecretory medication, abnormal endoscopy Patients: history of surgical manipulation of the upper GI tract, history of bleeding diathesis or coagulopathy, stroke or transient ischemic attack in the past 6 months, significant medical illness, oesophageal varices Index test: System: Bravo™ wireless capsule system Insertion: transorally Placement: 6 cm above the SCJ Comparator: System: not stated (catheter-based) Insertion: transnasally Placement: not stated Duration: 24 hours Foreign-body sensation Chest pain Throat discomfort Late detachment Oesophageal discomfort Eating and drinking Activity Sleep patterns Pandolfino et al. () Division of Gastroenterology, Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA Case series Level: IV Quality: Q2 CX (no comparator) P3 10 normal control subjects (7 males and 3 females, aged 21–53 years) 10 patients with GORD (6 males and 4 females, aged 20–54 years) Inclusion: Controls: no history of heartburn, reflux, chest pain or atypical symptoms Patients: oesophagitis (3) or an abnormal 24-hour oesophageal pH study prior to this study Exclusion: History of surgical manipulation of the upper GI tract, anticoagulation therapy, significant medical disease Controls: abdominal symptoms, use of antacids, abnormal upper endoscopy Index test: System: Bravo™ wireless capsule system Insertion: transorally Placement: 1 cm proximal to SCJ Duration: 24 hours Comparator: NA Chest discomfort Foreign-body sensation
Sofi et al. () Department of Gastroenterology, University of Toledo Medical Center, Toledo, Ohio, USA Retrospective case series 58 patients Age range: 26– 87 years 17 males, 41 females Inclusion: Not stated Exclusion: Not stated Index test: System: Bravo™ wireless capsule system Insertion: transorally Placement: 6 cm above the GOJ Comparator: NA Severe chest pain Throat pain Dysphagia Cough Work attendance Sweis et al. () Functional GI Disease Unit, Clinic for Gastroenterology and Hepatology, University Hospital of Zurich, Zurich, Switzerland Cohort study Level: III-2 Quality: 15/26 CX P1 134 patients Mean age: 60 years (range 18–76) 58 males, 76 females Compared with 110 consecutive catheter pH controls Mean age: 57 years (range 16–85) 44 males, 66 females Indications: Intolerance of catheter insertion, intolerance of catheter after intubation, or vomiting of catheter within 24 hours of the monitoring period Inclusion: Not stated Exclusion: Not stated Index test: System: Bravo™ wireless capsule system Insertion: transorally Placement: 6 cm proximal to the SCJ Duration: 48 hours Comparator: System: Slimline, Medtronic Insertion: transnasally Placement: 5 cm above the lower oesophageal high-pressure zone Duration: 24 hours Overall satisfaction Sweis et al. () Guy’s and St Thomas Hospitals, London, UK Case series Level: IV Quality: Q2 CX P2 38 patients 13 males, 25 females Median age: 41.6 years (range Indication: Reflux symptoms and no diagnosis of GORD on catheter-based pH monitoring Inclusion: Not stated Exclusion: Not stated Index test: System: Bravo™ wireless capsule system Insertion: transorally Placement: 6 cm proximal to the SCJ Duration: 96 hours Comparator: NA No patient complained of severe symptoms
Department of Surgery and Division of Gastroenterology, Oregon Health and Science University, Portland, Oregon, USA Level: IV Quality: Q1 CX (no comparator) P2 72 males and 114 females Mean age: 51 years Indications: Being evaluated for GORD Exclusion: Not stated Insertion: transnasally or transorally Placement: 5– 6 cm above the LOS or cm above the SCJ Duration: 48 hours Comparator: 24-hour Bravo monitoring Chest pain Tu et al. () Department of Internal Medicine and Department of Emergency Medicine, National Taiwan University Hospital, Taipei, Taiwan Prospective case series Level: IV Quality: Q1 CX (no comparator) P2 30 patients 20 males, 10 females Mean age: 57.6 ± 14.3 years (range 29–83) Indications: 24 patients with GORD were evaluated for drug effectiveness before surgery, 6 patients showed typical heartburn but their endoscopic findings were normal. Inclusion: Not stated Exclusion: Not stated Index test: System: Bravo™ wireless capsule system Insertion: transorally Placement: 6 cm proximal to the GOJ Duration: 48 hours Comparator: NA Mucosal abrasion and minor haemorrhage Turner et al. () Division of Gastroenterology, Brigham and Women’s Hospital, Boston, Massachusetts, USA Case series Level: IV Quality: Q2 CX (no comparator) P2 198 pH studies (148 studies had enough data to be included) Off medical therapy: 115 patients, 76 females, 39 males; mean age: 50 ± 13 years On medical therapy: 33 patients, 26 females, 7 males; mean age: 52 ± 14 years Indications: Typical and atypical symptoms of GORD or persistent GORD-related symptoms despite medical therapy. Patients with planned anti-reflux Inclusion: Not stated Exclusion: Not stated Index test: System: Bravo™ wireless capsule system Insertion: (during endoscopy) Placement: 6 cm above the SCJ Duration: 48 hours Comparator: NA Chest pain requiring capsule removal
Study profiles of included studies on direct Direct evidence Study setting Study design / Quality appraisal Study population Inclusion criteria / Exclusion criteria Diagnostic tests Health outcomes assessed Grigolon et al. () Department of Gastroenterology, Universita Degli Studi and Fondazione IRCCS Ca Granada, Ospedale Maggiore Policlinico, Milan, Italy Matched-pairs retrospective cohort study Level: III-2 Quality: 16.5/26 CX P2 102 patients Catheter group: 51 patients, 20 males, mean age 48 years (range Bravo group: 51 patients, 22 males, mean age 48 years (range 23–82) Inclusion: All consecutive patients who underwent wireless 96-hour pH monitoring between January and December 2007 off PPI therapy, and patients undergoing traditional 24-hour pH monitoring in the same period, after matching for the most troublesome symptom potentially to GORD, sex and age Exclusion: Not stated Index test: System: Bravo™ wireless capsule system Insertion: NA Placement: 6 cm above the SCJ Duration: 48–96 hours Comparator: System: Slimline mod 901P3001, Medtronic, Denmark Insertion: transnasally Placement: 6 cm above the point of sudden change in pH from acid to neutral as detected by means of continuous rapid withdrawal from the stomach or 5 cm above the upper margin of the LOS Duration: 24 hours Outcome of the principal symptom Sweis et al. () Guy’s and St Thomas Hospitals, London, UK Case series Level: IV Quality: Q2 CX P2 38 patients 13 males, 25 females Median age: 41.6 years (range 17–75) Indication: Reflux symptoms and no diagnosis of GORD on catheter-based pH monitoring Inclusion: Not stated Exclusion: Not stated Index test: System: Bravo™ wireless capsule system Insertion: transorally Placement: 6 cm proximal to the SCJ Duration: 96 hours Comparator: (24-, 48-, 72-hour Bravo pH monitoring) Improvement in symptoms / poor outcome (with 24-, 48-, Bravo as a comparator)
atypical symptoms including chest pain and extra oesophageal complaints Sofi et al. () Department of Gastroenterology, University of Toledo Medical Center, Toledo, Ohio, USA Retrospective case series 58 patients Age range: 26–87 years 17 males, 41 females Inclusion: Not stated Exclusion: Not stated Index test: System: Bravo™ wireless capsule system Insertion: transorally Placement: 6 cm above the GOJ Comparator: NA Technical efficacy: Early detachment (none) Device malfunction Recording failure Tankurt et al. () Kent Hospital, Department of Gastroenterology, Izmir, Turkey Case series Level: IV Quality: Q2 CX (no comparator) P2 64 patients (37 males, 27 females) Mean age: 37.9 years (range 25–58) Indications: Preoperative evaluation (17), evaluation of atypical reflux symptoms (40) and ‘other’ (7) Inclusion: Not stated Exclusion: Not stated Index test: System: Bravo™ wireless capsule system Insertion: NS Placement: 6 cm above the SCJ Duration: 48 hours Comparator: NA Technical efficacy: Early detachment Tseng et al. () Digestive Health Center, Department of Surgery and Division of Gastroenterology, Oregon health and Science University, Portland, Oregon, USA Retrospective case series Level: IV Quality: Q1 CX (no comparator) P2 190 procedures and 186 patients (some had the test performed twice) 72 males and 114 females Mean age: 51 years Indication: Being evaluated for GORD Inclusion: Patients older than 18 years Exclusion: Not stated Index test: System: Bravo™ wireless capsule system Insertion: transnasally or transorally Placement: 5–6cm above the LOS or 5–6 m above the SCJ Duration: 48 hours Comparator: 24-hour Bravo monitoring Technical efficacy: Loss of signal/data Early detachment Day-to-day variability Tu et al. () Department of Internal Medicine and Department of Emergency Medicine, National Prospective case series Level: IV Quality: Q1 CX (no 30 patients 20 males, 10 females Mean age: 57.6 ± 14.3 years (range 29–83) Indications: 24 patients with GORD were Inclusion: Not stated Exclusion: Not stated Index test: System: Bravo™ wireless capsule system Insertion: transorally Placement: 6 cm proximal to the GOJ Duration: 48 hours Technical efficacy: Attachment failure
Taiwan University Hospital, Taipei, Taiwan comparator) P2 evaluated for drug effectiveness before surgery, 6 patients showed typical heartburn but their endoscopic findings were normal Comparator: NA Turner et al. () Division of Gastroenterology, Brigham and Women’s Hospital, Boston, Massachusetts, USA Case series Level: IV Quality: Q2 CX (no comparator) P2 198 pH studies (148 studies had enough data to be included) Off medical therapy: 115 patients, 76 females, 39 males. Mean age: 50 ± 13 years On medical therapy: 33 patients, 26 females, 7 males. Mean age: 52 ± 14 years Indications: Typical and atypical symptoms of GORD or persistent symptoms despite medical therapy. Patients with planned anti-reflux surgery were also evaluated Inclusion: Not stated Exclusion: Not stated Index test: System: Bravo™ wireless capsule system Insertion: (during endoscopy) Placement: 6 cm above the SCJ Duration: 48 hours Comparator: System: Bravo™ wireless capsule system Insertion: transnasally Placement: Duration: 24 hours Technical efficacy Early detachment Insufficient data capture Day-to-day variability in oesophageal acid exposure Ward et al. () Division of Gastroenterology and Hepatology, Mayo Clinic, Jacksonville, Florida, USA Case series Level: IV Quality: Q2 CX (no comparator) P2 60 patients (58 patients had enough data to be included) 26 males, 34 females Mean age: 54 years (range Indications: Document GORD before surgery, possible GORD with negative PPI trial, evaluate response to PPI, possible supra-oesophageal GORD, non-cardiac chest pain, evaluate response to Stretta Inclusion: Not stated Exclusion: Not stated Index test: System: Bravo™ wireless capsule system Insertion: transorally Placement: 6 cm above the SCJ Duration: 48 hours Comparator: NA Technical efficacy: Attachment failure Hardware malfunction
procedure, previous failed pH test Wenner, Johnsson et al. () Department of Surgery, Lund University Hospital, Lund, Sweden Randomised crossover trial Level: II Quality: 20/26 CX P2 35 patients (31 patients had enough data to be included) 15 males, 16 females Median age: 52 years Median BMI: 27 (range 24–28) Indications: Typical reflux symptoms (55%) and atypical reflux symptoms (45%) Inclusion: Patients referred for oesophageal pH monitoring Exclusion: Patients with coagulopathy, severe oesophagitis/stricture, portal hypertension, a pacemaker, age <20 or >70 years, previous surgery, severe cardiopulmonary disease, symptoms suggestive of oesophageal motor disorders Index test: System: Bravo™ wireless capsule system Insertion: transorally Placement: 6 cm above the SCJ Duration: 48 hours Comparator: System: Slimline (Medtronic) Insertion: transnasally Placement: 5 cm above the upper border of the LOS Duration: 24 hours Technical efficacy: Technical problems Wenner et al. (); Wenner. Johansson et al. () Department of Surgery, Lund University Hospital, Lund, Sweden Case-control study Level: IV Quality: Q2 CX P3 70 patients, but 64 had enough data to be included (39 males, 25 females) and 55 controls (27 males and 28 females) Not all patients are included in the distal capsule outcomes Indications: Patients with typical reflux symptoms Inclusion: Patients: presence of typical reflux symptoms such as heartburn and regurgitation. Symptoms had to occur more than twice weekly. Treatment with medical acid suppression had to result in complete symptom relief or a more than 50% reduction of the symptoms Exclusion: Coagulopathy, severe oesophagitis/stricture, portal hypertension, pacemaker, <20 or >70 years of age, history of surgery, severe cardiopulmonary disease, symptoms suggestive of oesophageal motor disorders Index test: System: Bravo™ wireless capsule system Insertion: transorally Placement: 6 cm above the SCJ Technical efficacy: Early detachment Capsule unable to pass through oesophagus Transmission failure / loss of signal Incorrect capsule placement
Study profiles of included studies on linked evidence Diagnostic accuracy Study setting Study design / Quality appraisal Study population Inclusion criteria / Exclusion criteria Diagnostic tests Diagnostic accuracy outcome assessed Ayazi et al. () Department of Surgery, Keck School of Medicine, University of Southern California, Los Angeles, California, USA Diagnostic study Level: III-3 Quality: Patient selection: ? Index test: ? Reference standard: Flow and timing: ? CX P3 25 asymptomatic subjects and 25 patients Indications: Patients had heartburn and were responsive to PPI therapy. All had hiatal hernia Inclusion: Not stated Exclusion: Not stated Index test: System: Bravo™ wireless capsule system, Medtronic Inc. Minneapolis Minnesota Insertion: transnasally Placement: 5 cm above the LOS Duration: 48 hours Comparator: NA Reference standard: Clinical diagnosis (heartburn, responsive to PPI therapy and evidence of a hiatal hernia) Sensitivity Specificity Accuracy Ayazi et al. ()11 Department of Surgery, Keck School of Medicine, University of Southern California, Los Angeles, California, USA Diagnostic study Level: III-3 Quality: Patient selection: Index test: ? Reference standard: Flow and timing: CX P3 115 symptomatic patients who were tested for GORD (28 patients with strong clinical evidence, 77 with intermediate evidence, and 10 with minimal evidence, of GORD Inclusion: Not stated Exclusion: Not stated Index test: System: Bravo™ wireless capsule system, Medtronic Inc. Minneapolis Minnesota Insertion: transnasally Placement: 5 cm above the LOS Duration: 48 hours Comparator: NA Reference standard: Clinical diagnosis (primary symptoms of heartburn and/or regurgitation, response to PPI therapy >50%, hiatal hernia >2 cm, oesophageal mucosal injury) Sensitivity Specificity PPV NPV Accuracy
Disease, Ersta Hospital, Stockholm, Sweden Level: III-3 Quality: Patient selection: ? Index test: Reference standard: ? Flow and timing: C1 P2 30 females and 15 males in volunteer group 27 females and 20 males in patient group Mean age: Volunteers: 47 years (range 21–68) Patients: 50 years (range 23–69) Indication: Patients had symptoms including mainly heartburn, acid regurgitation, and chest or epigastric pain Volunteers: history of GORD or any other pathology of the upper GI tract, taking acid-suppressing agents or medication known to affect GI motility Duration: 48 hours Comparator: System: Slimline, Medtronic, Skovlunde, Denmark Insertion: transnasally Placement: 5 cm proximal to the upper border of the LOS Duration: 24 hours LR– Pandolfino et al. () Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA Diagnostic study Level: III-3 Quality: Patient selection: Index test: ? Reference standard: ? Flow and timing: Q1 CX (clinical diagnosis) P3 44 controls (13 males, 31 females, aged years) 41 patients (26 males, 15 females, aged 32–72 years) Inclusion: Not stated Exclusion: Controls: abdominal symptoms, use of antacids or antisecretory medication, abnormal endoscopy Patients: history of surgical manipulation of the upper GI tract, history of bleeding diathesis or coagulopathy, stroke or transient ischemic attack in the past 6 months, significant medical illness, oesophageal varices Index test: System: Bravo™ wireless capsule system Insertion: transorally Placement: 6 cm above the SCJ Comparator: NA Reference standard (diagnosis of patients in study population): 25 patients had erosive oesophagitis, 6 had an abnormal 24-hour pH study, 10 were diagnosed clinically with typical GORD symptoms that resolved with PPI therapy Sensitivity Specificity PPV NPV LR+ LR– Wenner, Johnsson et al. () Department of Surgery, Lund Randomised crossover trial 35 patients (31 patients had enough data to be included) Inclusion: Patients referred for oesophageal pH monitoring Index test: System: Bravo™ wireless capsule system Insertion: transorally Sensitivity Specificity PPV NPV
School of Medicine, Chicago, Illinois, USA 4-day data acquisition Indications: Acid reflux symptoms, chest pain, laryngeal symptoms that were poorly responsive to twice-daily PPI therapy for a minimum of 6 weeks Comparator: NA Gillies et al. () Departments of Upper Gastrointestinal Surgery and Gastrointestinal Physiology, Royal Berkshire Hospital, Reading, UK Diagnostic yield study Level: IV 95 patients Indication: Symptoms suggestive of GORD or documenting the outcome of laparoscopic anti-reflux surgery Inclusion: See indication Exclusion: No specific exclusion criteria exist Index test: System: Bravo™ wireless capsule system Insertion: transorally Placement: 6 cm proximal to the SCJ Duration: 48 hours Accuracy: Diagnostic yield Grigolon et al. () Department of Gastroenterology, Universita Degli Studi and Fondazione IRCCS Ca Granada, Ospedale Maggiore Policlinico, Milan, Italy Matched-pairs retrospective cohort study Level: III-2 Quality: 16.5/26 C1 P2 102 patients Catheter group: 51 patients, 20 males, mean age 48 years (range Bravo group: 51 patients, 22 males, mean age 48 years (range 23–82) Inclusion: All consecutive patients who underwent wireless 96-hour pH monitoring between January and December 2007 off PPI therapy, and patients undergoing traditional 24-hour pH monitoring in the same period, after matching for the most troublesome symptom potentially related to GORD, sex and age Exclusion: Not stated Index test: System: Bravo™ wireless capsule system Insertion: NA Placement: 6 cm above the SCJ Duration: 48–96 hours Comparator for concordance: System: Slimline mod 901P3001, Medtronic, Denmark Insertion: transnasally Placement: 6 cm above the point of sudden change in pH from acid to neutral as detected by means of continuous rapid withdrawal from the stomach, or 5 cm above the upper margin of the LOS Duration: 24 hours Accuracy: Diagnostic yield Concordance (acid exposure time) Incremental diagnostic yield (of prolonged monitoring) Gunnarsdottir, Diagnostic yield 58 children Inclusion: Index test: Accuracy:
complaints Schneider et al. () Department of General, Visceral, and Transplant Surgery, University Hospital of Tubingen, Tubingen, Germany Non-randomised controlled trial Level: III-2 Quality: 9/26 CX P3 123 patients Bravo group: 36 males and 32 females, mean age 51 years (range Catheter group: 29 males and 26 females, mean age 43 years (range Inclusion: Not stated Exclusion: Not stated Index test: System: Bravo™ wireless capsule system Insertion: transorally Placement: 5 cm above the upper border of the LES Duration: 48 hours Comparator: System: not stated Insertion: transnasally Placement: not stated Duration: 24 hours Accuracy: Concordance (acid exposure, number of reflux episodes) Sweis et al. () Functional GI Disease Unit, Clinic for Gastroenterology and Hepatology, University Hospital of Zurich, Zurich, Switzerland Diagnostic yield study Level: IV 134 patients Mean age: 60 years (range 18–76) 58 males, 76 females Compared with 110 consecutive catheter pH controls Mean age: 57 years (range 16–85) 44 males, 66 females Indications Patients: Intolerance of catheter insertion, intolerance of catheter after intubation, or vomiting of catheter within 24 hours of the monitoring period Inclusion: Not stated Exclusion: Not stated Index test: System: Bravo™ wireless capsule system Insertion: transorally Placement: 6 cm proximal to the SCJ Duration: 48 hours Accuracy: Diagnostic yield Sweis et al. () Guy’s and St Diagnostic yield study 38 patients 13 males, 25 females Inclusion: Not stated Index test: System: Bravo™ wireless capsule system Accuracy: Incremental diagnostic yield
Thomas Hospitals, London, UK Level: IV Median age: 41.6 years (range 17–75) Indication: Reflux symptoms and no diagnosis of GORD on catheter-based pH monitoring Exclusion: Not stated Insertion: transorally Placement: 6 cm proximal to the SCJ Duration: 96 hours Comparator: 24-, 48-, 72-hour Bravo pH monitoring (of prolonged monitoring) Ward et al. () Division of Gastroenterology and Hepatology, Mayo Clinic, Jacksonville, Florida, USA Diagnostic yield study Level: IV Quality: Q2 CX (no comparator) P2 60 patients (58 patients had enough data to be included) 26 males, 34 females Mean age 54 years (range 27–82) Indications: Document GORD before surgery, possible GORD with negative PPI trial, evaluate response to PPI, possible GORD, chest pain, evaluate response to Stretta procedure, previous failed pH test Inclusion: Not stated Exclusion: Not stated Index test: System: Bravo™ wireless capsule system Insertion: transorally Placement: 6 cm above the SCJ Duration: 48 hours Accuracy Diagnostic yield Wenner, Johnsson et al. () Department of Surgery, Lund University Hospital, Lund, Sweden Randomised crossover trial Level: II Quality: 20/26 35 patients (31 patients had enough data to be included) 15 males, 16 females Median age: 52 years Median BMI: 27 (range 24–28) Indications: Typical reflux symptoms (55%) and atypical reflux Inclusion: Patients referred for oesophageal pH monitoring Exclusion: Patients with coagulopathy, severe oesophagitis/stricture, portal hypertension, a pacemaker, age <20 or >70 years of age, previous surgery, severe cardiopulmonary disease, symptoms Index test: System: Bravo™ wireless capsule system Insertion: transorally Placement: 6 cm above the SCJ Duration: 48 hours Comparator: System: Slimline (Medtronic) Insertion: transnasally Placement: 5 cm above the upper border of Accuracy: Concordance in acid exposure time Comparative diagnostic yield
Cochrane Library Quality: 23/27 multiple studies in the UK, one study was conducted in 11 European countries, and one study was conducted in a centre in Canada. Sample sizes ranged from 104 to 554 participants, with a total of 1,232 randomised patients comparing medical management with laparoscopic fundoplication surgery Exclusion: Non-randomised studies types) Comparator: Medical management: either PPIs or histamine receptor antagonists (H2RAs) Heartburn Regurgitation (acid reflux) Dysphagia Other GORD-related symptoms Conversion to open surgery Intraoperative complications Postoperative complications Admission to intensive treatment unit / unit Reoperation Mortality during index admission Medication use Length of operation Length of hospital stay Time off work Visits to GP due to GORD Visits to hospital due to GORD pH monitoring (% time pH <4 / DeMeester score) Manometry (LOS pressure) Endoscopy Other complications or adverse events False positives Study setting Study design Study population / Included studies Inclusion criteria / exclusion criteria ‘True diagnosis’ and misdiagnosis Health outcomes assessed
CX P2 Cohort study 66 participants wireless group Hakanson et al. (2009) Level III-2 Quality: 14/26 CX P2 Case-control study 45 volunteers and 47 patients (simultaneous recording) 0 complications 0 complications NS Gillies et al. (2007) Level III-2 Quality: 13.5/26 CX P2 Non-randomised controlled trial 100 participants catheter group 85 participants wireless group (but 100 studies) 27% no overall discomfort 23% discomfort score >5 86% no impact on work attendance 3% no overall discomfort 45% discomfort score >5 18% no impact on work attendance <0.0001 NS <0.0001 Pandolfino et al. (2003) Level III-2 Quality: 11.5/26 CX P3 Case-control study 30 participants catheter group 29 participants wireless group Satisfaction (the lower the better): 0.8 ± 0.1 Throat discomfort: 4/29 Oesophageal discomfort: 10/29 Change daily routine: 0/29 Affected diet: 3% Affected activity: 0% Disrupted sleep: 2/22 Satisfaction (the lower the better): 1.9 ± 0.2 Throat discomfort: 22/30 Oesophageal discomfort: 5/30 Change daily routine: 11/30 Affected diet: 47% Affected activity: 60% Disrupted sleep: 9/30 <0.001 <0.001 <0.05 <0.001 <0.001 NS Wireless group: 2 subjects had discomfort to the extent that the capsule had to be removed; 1 4 had moderate chest pain Schneider et al. (2007) Level III-2 Quality: 9/26 CX P3 Non-randomised controlled trial 55 participants catheter group 78 participants wireless group Throat discomfort: 3 (3.8%) Oesophagus discomfort: 14 (17.9%) Reduced activities: 5 (6.4%) Reliability: 75 (96.1%) Throat discomfort: 52 (94.5%) Oesophagus discomfort: 18 (32.7%) Reduced activities: 55 (100%) Reliability: 54 (98.1%) 0.001 NS 0.0001 NS
Azzam et al. (2012)a Level IV Q1 In-subject simultaneous recording study 25 patients 0/25 procedures No patient experienced severe chest pain or any other symptom requiring endoscopic removal of the capsule Prakash et al. (2006) Level IV Q2 Retrospective case series 452 patients 8/452 procedures (but this only gives the major side effects of the patients who requested removal of the capsule) 7 severe chest pain and/or odynophagia 1 severe foreign-body sensation Bhat, McGrath & Bielefeldt (2006) Level IV Q2 Prospective case series 203 patients 19/203 procedures 18 significant chest discomfort 1 rash Turner et al. (2007) Level IV Q2 Case series 191 patients 1/191 procedures 1 intolerable chest pain requiring capsule removal Domingues, & Domingues (2011) Level IV Q2 Retrospective case series 74 patients 19/74 procedures 17 mild foreign-body sensation 2 chest pain during meal periods Scarpulla et al. (2007) Level IV Q2 Retrospective case series 83 patients 21/83 procedures 21 occasional retrosternal discomfort on swallowing Francis (2008) Level IV Q2 Retrospective case series 76 patients 4/76 procedures 1 severe chest pain 1 capsule dislodgement in the mouth 1 capsule dislodgement in the pyriform sinus 1 capsule dislodgement in the stomach de Hoyos & Esparza (2010); de Hoyos, Esparza & Loredo (2010) Level IV Q2 Prospective case series 66 patients 2/66 procedures 1 intolerable chest pain 1 detachment failure Tankurt et al. (2011) Level IV Q2 Case series 64 patients 11/64 procedures 11 mild to moderate retrosternal pain or discomfort Garrean et al. (2008) Level IV Q2 Post-test case series 60 patients 8/60 procedures 3 back pain 3 throat pain 1 globus sensation 1 chest pain Belafsky et al. (2004) Level IV Q2 Prospective case series 46 patients 9/46 procedures 2 laryngospasm 2 epistaxis 1 vasovagal reaction 4 foreign-body sensation Sweis et al. (2011) Level IV Q2 Case series 38 patients 0/38 procedures No patient complained of severe symptoms during the study and no capsule needed to be removed Calabrese et al. (2008) Level IV Q2 Post-test case series 24 patients 5/24 procedures 5 occasional retrosternal discomfort on swallowing
diverticulum Kramer & Chokhavatia (2012) Case report 1 patient 1/1 procedure: 1 capsule dislodgement in the left pyriform sinus Shahid & Fisher (2011) Case report 1 patient 1/1 procedure: 1 capsule dislodgement in the left mainstem bronchus Triester et al. (2005) Case report 1 patient 1/1 procedure: 1 sharp substernal chest pain and dyspnoea Renteln et al. (2008) Case report 1 patient 1/1 procedure: 1 capsule aspiration and decreased oxygen saturation Table Chest discomfort / complications resulting from catheter-free (wireless) oesophageal pH monitoring in adults Study Level and quality Population Chest discomfort / complications per procedure Lacy et al. (2011) Level IV Q1 Post-test case series 375 patients 1/375 procedures 1 transient chest discomfort Crowell et al. (2008) Level IV Q1 Case series 294 patients 203/294 procedures 121 chest discomfort 82 chest pain Tseng et al. (2005) Level IV Q1 Retrospective case series 190 procedures, 186 patients 2/190 procedures 2 sufficient chest pain Ahlawat et al. (2006) Level IV Q1 Retrospective case series 82 patients 4/82 procedures 4 severe chest pain 53 patients were physically aware of the presence of the pH-monitoring capsule in the oesophagus, with symptoms ranging from a foreign-body sensation to a mild discomfort, to chest pain Tharavej et al. (2006) Level IV Q1 Case series 80 patients 10/80 procedures 10 new onset chest pain In 6 of these patients the chest pain was associated with hypertensive oesophageal contractions Remes-Troche et al. (2005) Level IV Q1 Prospective case series 77 patients 26/77 procedures 26 chest pain Marchese et al. (2006) Level IV Q1 Prospective case series 39 patients 2/39 procedures 2 severe retrosternal chest pain Azzam et al. (2012)a Level IV Q1 In-subject simultaneous recording study 25 patients 0/25 procedures No patient experienced severe chest pain or any other symptom requiring endoscopic removal of the capsule
Appendix F Non-comparative technical efficacy data Table Technical efficacy of catheter-free (wireless) oesophageal pH monitoring in adults Study Study design N Technical/operative/equipment/recording failure Lacy et al. (2011) Case series Level: IV Quality: Q1 CX P2 358 patients 6/358 procedures: (1.7%) 6 early detachments or loss of signal Nusrat, Roy & Bielefeldt (2012) Retrospective case series Level: IV Quality: Q1 CX P2 356 patients 6/356 procedures: (1.7%) 6 early detachments Park et al. 2013 (2013) Case series Level: IV Quality: Q1 CX P2 230 patients 32/230 procedures: (13.9%) 17 early detachments 10 attachment failures or misplacements 5 recording failures Tseng et al. (2005) Retrospective case series Level: IV Quality: Q1 CX P2 209 patients (and 213 procedures) 23/213 procedures (10.8%): 18 incomplete data captures (<18 hours on at least 1 day) 5 early detachment Crowell et al. (2009) Case series Level: IV Quality: Q1 CX P2 180 patients 15/180 procedures (8.3%) 15 early detachments Doma et al. (2010) Post-test case series Level: IV Quality: Q1 CX P2 161 patients 56/161 procedures: (38.0%) 56 errors in placement (inaccurate placement of the capsule) Iqbal et al. (2007) Retrospective case series Level: IV Quality: Q1 CX P2 100 patients 11/100 procedures (11.0%) 11 early detachments Ahlawat et al. (2006) Retrospective case series Level: IV Quality: Q1 CX P2 90 patients 9/90 procedures: (10.0%) 3 failure to transmit data to receiver 1 capsule failed to deploy from catheter 4 incomplete data captures 1 failure of attachment to the oesophageal mucosa
Grigolon et al. (2011)a One arm of matched pairs retrospective cohort study Level: IV Quality: Q2 CX P2 57 patients in the catheter-free group 6/57 procedures (10.5%): 3 incomplete data capture 3 early detachment Belafsky et al. (2004) Prospective case series Level: IV Quality: Q2 CX P2 46 patients 6/46 procedures (13.0%): 2 failures because of tight nasal vault 2 early detachments 1 lost data recorder 1 capsule failed to deploy from catheter Sweis et al. (2011) Case series Level: IV Quality: Q2 CX P2 38 patients 0/38 procedures (0%): 0 early detachments (detachment occurred between 48 and 72 hours in 5 patients and between 72 and 96 hours in 12 patients) Martinez de Haro et al. (2008)a One arm of controlled trial Level: IV Quality: Q2 CX P2 25 patients and 10 volunteers 6/35 procedures (17.1%) 3 incorrect placements 2 early detachments 1 immediate detachment with aspiration Bechtold et al. (2007) Retrospective case series Level: IV Quality: Q2 CX P2 27 patients 1/27 procedures (3.7%): 1 early detachment Francis et al. (2012)a Randomised controlled trial Level: IV Quality: Q2 C1 P2 22 patients 0/22 procedures (0%): All capsules were placed successfully on the first attempt Pandolfino et al. (2006)a Case-control study Level: IV Quality: Q2 CX (clinical diagnosis) P3 10 patients and 10 volunteers 2/20 procedures (10%): 2 early detachments Sofi et al. (2011) Retrospective case series Level: IV Quality: Q3 CX P2 58 patients 5/58 procedures (8.6%): 2 malfunctions of the device during insertion 3 transmission failures
Lee et al. (2005) Prospective case series Level: IV Quality: Q3 CX P2 40 patients 4/40 procedures (10%): 3 attachment failures 1 early detachment a These studies are not case series but are still included as level IV safety evidence because they do not report a(n) (appropriate) comparison regarding technical efficacy. Table Technical efficacy of catheter-free (wireless) oesophageal pH monitoring in children Study Study design N Technical/operative/equipment/recording failure Cabrera et al. (2011) Prospective case series Level: IV Quality: Q1 CX P2 289 children 41/289 procedures (14.2%) 3 capsules failed to calibrate 8 failures of attachment to the oesophageal mucosa 4 capsules failed to deploy from catheter 1 recording failure 4 early detachments 21 incomplete data captures Gunnarsdottir, Stenstrom & Arnbjornsson (2007, 2008) Case series Level: IV Quality: Q1 CX P2 58 children 3/58 procedures (5.2%): 1 transmission failure 2 attachment failures Hochman & Favaloro-Sabatier (2005) Retrospective case series Level: IV Quality: Q2 CX P2 50 children 5/50 procedures (10%): 1 failure of attachment to the oesophageal mucosa 4 shorter monitoring periods