bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 19261: The Association Between Testosterone Replacement Therapy and Adverse Cardiovascular Outcomes in Veterans Undergoing Coronary Angiography
Authors: Vigen Rebecca , Barqawi Al , Maddox Thomas M , Grunwald Gary , O'Donnell Colin , Enright James , Ho P M
Published: April 2024

Background:
Adverse cardiac events were not demonstrated in randomized controlled trials of testosterone replacement therapy (TRT) in men until 2009 when the Testosterone in Older Men with Mobility Limitations trial was halted due to increased cardiac events in the treatment group. Therefore, the safety of TRT in older men with medical comorbidities is under debate.

Methods:
We used the VA CART-CL registry to identify all veterans undergoing coronary angiography between 2005 and 2011 who had total testosterone levels ≤ 250 ng/dL measured post-procedure. We derived a propensity-matched (2:1) cohort of patients dispensed TRT to patients not dispensed TRT. Multivariable Cox regression assessed the association between TRT and myocardial infarction (MI) or death treating TRT as a time varying covariate. We also evaluated this association within strata of CAD: no CAD, nonobstructive CAD (>20% stenosis in any vessel), and obstructive CAD (≥ 70% in any vessel or ≥ 50% in the left main).

Results:
Of the 3,375 veterans who had a total testosterone level ≤ 250, 461 (12%) were initiated on TRT after a mean of 546 days (median 463 days) after coronary angiography. No significant differences were observed in the baseline characteristics of the TRT and non-TRT propensity matched groups including mean age (61), hypertension (89%), diabetes (55%), and mean testosterone level (166). In multivariable analyses, there was a significant interaction between TRT and CAD strata (p=0.04). Among veterans with no CAD or nonobstructive CAD, there was no association between TRT and MI/death (p=0.46 and p=0.3, respectively). Among those with obstructive CAD, TRT was associated with significantly increased risk of MI/death (HR 2.51; 95% CI 1.6 - 3.94).

Conclusion:
In this cohort of veterans undergoing coronary angiography with low testosterone levels, TRT can be associated with increased risk of MI/death as compared to no TRT. This risk appears to be present in patients with obstructive CAD but not among patients with less severe CAD. These findings may have potential implications for targeting testosterone use among selected patient populations.
Abstract 19280: Computational Fluid Dynamics Predicts Correlations between Transluminal Contrast and Pressure Gradients in Models of Stenosed Arteries
Authors: Lardo Albert C , Seo Jung H , Eslami Parastou , Mittal Rajat
Published: April 2024

Background:
Recent computed tomography coronary angiography (CTCA) studies have noted the presence of transluminal contrast gradients (TCG) in stenosed arteries but the mechanism and significance of TCG is unknown.

Objective:
Use computational fluid dynamics (CFD) modeling to determine mechanisms of contrast dispersion and correlate TCG to transstenotic pressure gradient (TPG) in models of stenosed coronary arteries.

Methods:
Simulations of flow and contrast dispersion in simple 2-dimensional models of coronary stenosis were carried out. Models with symmetric and asymmetric stenosis of varying severities (25%-75%) were employed. Key parameters including Reynolds and Womersley numbers were also varied. Simulations predict the variations of flow, pressure and contrast concentration in arterial models. Data from the simulations was analyzed to generate correlations between and contrast dispersion patterns and TPG with increasing stenosis severity. For extracting transluminal correlations, pressure and contrast concentration are averaged across the cross-section of the lumen and the contrast gradient is normalized by the maximum concentration at the inlet of the model.

Results:
Simulations predict the variations of flow, pressure and contrast concentration in arterial models (see figure). The data shows a direct but nonlinear correlation between TCG and TPG. A comparison of contrast dispersion in symmetric and one-sided stenoses also indicates that the correlation between TCG and TPG is sensitive to lesion geometry; the TCG for a symmetric lesion correlates to a higher TPG than a one-sided lesion.

Conclusions:
The current result is the first direct evidence that TCG may encode for vessel hemodynamics and that lesion geometry also modulates this relationship. CFD modeling provides data for determining important mechanistic insights into TCG and may be used to “decode” flow resistance from CTCA exams.
Abstract 19281: Outcomes Following Cardioversion and Atrial Fibrillation Ablation in Patients Treated with Rivaroxaban and Warfarin in the ROCKET AF Trial
Authors: Piccini Jonathan P , Stevens Susanna , Lokhnygina Yuliya , Patel Manesh , Singer Daniel , Halperin Jonathan , Hankey Graeme , Hacke Werner , Becker Richard , Nessel Christopher , Mahaffey Kenneth , Fox Keith , Califf Robert , Breithardt Gúnter
Published: April 2024

Background:
There are limited data regarding cardioversion and atrial fibrillation (AF) ablation in patients receiving novel, oral anti-Xa inhibitors.

Methods:
We compared the incidence of electrical cardioversion (ECV), pharmacologic cardioversion (PCV), or AF ablation and subsequent outcomes in the ROCKET AF trial.

Results:
Over a median follow-up of 2.1 years, 143 patients underwent ECV, 142 underwent PCV, and 79 underwent catheter ablation. The rate of ECV, PCV, or AF ablation was 1.44 per 100 patient-years in the warfarin arm and 1.46 per 100 patient-years in the rivaroxaban arm. In the adjusted analysis, the incidences of stroke or systemic embolism (HR 1.04; 95% CI 0.46-2.33), cardiovascular death (HR 1.24; 95% CI 0.55-2.78), and all-cause death (HR 1.43; 95% CI 0.74-2.77) were not significantly different following ECV, PCV, or AF ablation. Hospitalization was increased following ECV, PCV, or AF ablation (HR 2.16; 95% CI 1.63-2.86), and there was no evidence of a differential effect by randomized treatment (p for interaction=0.90). Event counts were similar in the rivaroxaban- and warfarin-treated patients following ECV, PCV, or AF ablation, including stroke or systemic embolism or death from any cause (Figure).

Conclusions:
Despite an increase in hospitalization, there was no difference in long-term stroke rates or survival following cardioversion or AF ablation. Outcomes following cardioversion or ablation were similar in those treated with rivaroxaban or warfarin.
Abstract 19311: Obesity is Associated with Increased Rates of Revascularization in Coronary Artery Bypass Grafting Patients: A Large Cohort Study
Authors: Martin Billie-Jean , Lee Adriane M , Southern Danielle A , Galbraith P D , Norris Colleen M , Knudtson Merill L , APPROACH Investigators
Published: April 2024

Introduction:
While excess mass has been demonstrated to be associated with improved survival in subjects with coronary artery disease (CAD), other potential outcomes have not been considered. The objective of this study was to assess the relationship between obesity and repeat revascularization in subjects who have undergone coronary artery bypass grafting (CABG).

METHODS: The Alberta Provincial Project for Outcomes Assessment in Coronary Heart Disease database was used to obtain information on subjects who underwent CABG between 1995 and 2010. Subjects were classified as normal weight (BMI 18.5-24.9), overweight (25-29.9), obese class I (30-34.9), obese class II (35-39.9), or obese class III (≥40 kg/m2). Outcome of interest was time to repeat revascularization: the 1st percutaneous coronary intervention or CABG after index CABG. Cox proportional hazard models were used to determine the association between adiposity and freedom from repeat revascularization. Results: There were 13416 subjects included in this study, 23% normal weight. The more obese subjects were younger and had a higher prevalence of diabetes (p<0.0001 across categories). Median follow-up time was 6.3 years; there were 1029 subjects who underwent repeat revascularization. In unadjusted models BMI was associated with increased revascularization (overweight Hazard Ratio (HR), 1.22, 95%CI 1.03, 1.45; Obese Class I 1.22, 95%CI 1.01, 1.48; Obese Class II/III 1.60, 95%CI 1.28, 2.00). This association persisted following adjustment for sex, age and clinical characteristics in overweight (HR 1.20, 95%CI 1.01, 1.42) and obese class II/III subjects (HR 1.41, 95% CI 1.12, 1.77). Discussion: Despite improved survival in obese subjects with CAD, we found obesity is associated with an increased risk of revascularization. This may represent elevated residual risk in obese patients. This finding is novel, and highlights the need to pay particular attention to residual risk in obese subjects with CAD.
Abstract 19347: The Mouse Mast Cell Protease 4 is Involved in the Generation of Endothelin-1 in vitro and in vivo
Authors: Houde Martin , Labonté Julie , Desbiens Louisane , Jamain Marc , Pejler Gunnar , Gurish Michael , Takai Shinji , D'Orléans-Juste Pedro
Published: April 2024

The serine protease chymase converts intravenously (iv)- administered big-endothelin-1 to endothelin-1 (ET-1) in the mouse in vivo. The mouse mast cell protease 4 (mMCP-4) is among eight chymase-like murine isoforms and is involved in the generation of angiotensin-II (Ang-II) from its precursor Ang-I. It remains to be determined which chymase isoform is involved in the endothelin-converting enzyme -independent production of ET-1. In the present study, the contribution of mMCP-4 was determined in the conversion of exogenous Big-ET-1 in vitro and in vivo as well as in the tissue production of endogenous ET-1. In vitro analyses were performed from cardiac left ventricle, aorta, kidneys and lungs homogenates derived from wild type (WT) and mMCP-4 KO mice. The pressor response in anaesthetized mice to Big-ET-1, but not ET-1 (1-31) or ET-1 was significantly reduced in mMCP-4 KO mice compared to their WT congeners. Furthermore, a selective chymase inhibitor, TY-51469, significantly reduced the pressor response to Big-ET-1 in WT but not mMCP-4 KO mice. Radio-telemetry analysis in free-moving, conscious mice revealed no differences in basal blood pressure between WT and mMCP-4 KO mice. TY-51469 also inhibited the in vitro hydrolysis a chymotrypsin-sensitive fluorogenic peptide in soluble fractions derived from WT but not mMCP-4 KO tissues. HPLC-MALDI-MS analysis revealed that supernatants from WT but not mMCP-4 KO mice could yield ET-1 (1-31) from Big-ET-1 in vitro, and that this conversion is blocked by TY-51469 in WT samples. The in vivo conversion of iv-administered Big-ET-1 to plasmatic ET-1 (1-31) and ET-1 was also reduced in mMCP-4 KO mice compared to their WT congeners. Finally, tissue levels of immunoreactive ET-1 were reduced by 40% in lung homogenates from mMCP-4 KO mice when compared to those from WT congeners. We conclude that mMCP-4 is the predominantly involved chymase isoform in the production of endogenous ET-1 in the mouse model.
Abstract 19392: Endothelial Knockout of Polycystin 1 (PC1) Alters Mitochondrial Functions and Bioenergetics
Authors: Pung Yuh Fen , Adapala Ravi K , Burke Jamie R , Geldenhuys Werner J , Chilian William M , Thodeti Charles K , Jones Thomas J
Published: April 2024

Polycystin 1 (PC1) is a mechanosensitive component of shear stress sensing in endothelial cells. Shear stress is a critical determinant of endothelial proliferation, migration and differentiation, which are energy dependent processes. Since, mutations in PC1 impair shear-induced endothelial functions, we hypothesized PC1 may mediate its effects through mitochondrial-dependent energy production. In the present study, we measured mitochondrial function using the Seahorse XF24-3 flux analyzer in wild type and PC1 null endothelial cells. We found that the maximal oxygen consumption rate (OCR) and extracellular acidification rate (glycolysis) (ECAR) were 2-fold lower in PC1 null cells compared to Wt (p<0.05) in response to the mitochondrial uncoupler, FCCP (0.5 µmol/L). PC1 null cells also exhibited a 10-fold reduction in bioenergetic reserve capacity (p<0.05), indicating a severe mitochondrial dysfunction. Further, we found these cells show a 3.5-fold decrease in peroxisome proliferator-activated receptors gamma (PPAR gamma) coactivator-1 alpha (PGC-1 alpha) and a 4-fold decrease in the mitochondrial uncoupling protein 2 (UCP2) expression. Importantly, the mutant cells showed a 2-fold increase in the mitochondrial membrane potential as measured by a selective mitochondrial potential indicator, JC-1. Finally, we found that PC1 null cells showed an increased production of ROS as assessed by DHE and Mitosox staining. Importantly, there were no changes in mitochondrial abundance between PC1 and WT cells. Taken together, these results indicate the absence of PC1 impairs mitochondrial function and may contribute to the endothelial dysfunction observed in polycystic kidney disease (PKD).
Abstract 19632: Appropriate Use of Inpatient Repeat Echocardiography in a Tertiary Care Center
Authors: Vellanki Anu , Baker Stephen P , Aurigemma Gerard P , Tighe Dennis A
Published: April 2024

Background:
Echocardiography is used with increasing frequency to address clinical cardiac questions. With its increasing use, criteria have been promulgated for the appropriate use (AUC) of Echo by the ACC/ASE. Little information currently exists on the inpatient use of transthoracic echocardiography (TTE) when a prior study (repeat) has been performed recently. Our aim was to study the application of 2011 AUC criteria on clinical management for inpatient repeat TTE in a tertiary care center.

Methods:
Over a 1-month period in 2012, written requests for 500 consecutive inpatient TTEs were evaluated. The echo database was queried to determine if a TTE had been performed within 1 yr. Indications for repeat TTE were categorized as appropriate (A), uncertain (U) and inappropriate (I) based on AUC criteria. A retrospective chart review was performed to assess impact of the AUC categorized results on clinical management.

Results:
Of the 500 TTEs, 131(26%) were repeat studies. Per AUC, 49% were considered A, 17% U and 34% I. Among these repeat TTEs, 53% played a role in clinical management, while 47% had no discernible role. A significant difference was found in clinical management among A, U, I groups (84.4% vs. 50% vs. 8.9%, p<0.0001). Of 131 repeat TTEs, 39(30%) were ordered by cardiology while non- cardiology providers ordered 92(70%). The top 3 indications of (A) TTEs were heart failure (22%), pericardial effusion (15%) and hemodynamic instability (15%), while (I) TTEs were heart failure (26%), syncope (12%) and pericardial effusion (11%). No significant difference was found among cardiology and non-cardiology providers in ordering A, U and I TTEs (41% vs. 53.5%, p=0.4, 20.5% vs. 16.3%, p=0.4 and 38.5% vs. 30.2%, p=0.4).

Conclusions:
Approximately one-third of repeat TTEs in a tertiary care medical center can be classified as (I). Noncardiology services were comparable to cardiology providers in applying AUC criteria. In an effort to reduce (I) repeat TTEs, knowledge of prior TTE data and incorporation of AUC criteria into order entry mechanisms should occur to aid inpatient provider decisions on ordering TTEs.
Abstract 19768: eNOS Uncoupling Leads to Endothelial Dysfunction in Clinical Obstructive Sleep Apnea (OSA): Role of BH4 Depletion
Authors: Varadharaj Saradhadevi , Wannemacher Jacob , Patt Brian , Reyes Levy , Jay Zweier L , Khayat Rami
Published: April 2024

OSA is increasingly recognized as a cardiovascular risk factor and is a cause of hypertension, worsening coronary disease and heart failure. OSA leads to endothelial dysfunction (ED) and decreased Nitric oxide (NO) availability. The mechanism of ED in OSA remains unknown. We previously found that OSA causes increased peroxynititrite production in the endothelium. We hypothesized that increased peroxynitrite would result in oxidative modification of proteins and decreased BH4 availability.

Methods:
Participants were 13 patients with recently diagnosed OSA and 10 healthy individuals with low cardiovascular risk. OSA Patients underwent subcutaneous forearm biopsy and doppler measurements of endothelial function by flow mediated dilation (FMD) prior to, and 12 weeks after initiation of treatment. Non-OSA controls also had FMD measurements and biopsies. NO and superoxide (
·
O
2

_

) levels in the microcirculation were determined using fluorescent probes CuFL and DHE respectively in the absence or presence of the NO synthase inhibitor, L-NAME, the NO scavenger, PTIO, and the SOD mimetic, MnTBAP.

Results:
OSA patients had impaired FMD, compared to non-OSA controls, which decreased after 12 weeks of CPAP treatment. OSA patients had increased endothelial
·
O
2

_

and decreased NO production compared to controls. CPAP treatment decreased
·
O
2

_

and increased NO production in OSA patients. Incubation of subcutaneous sections with BH4 resulted in a significant increase in NO and decrease in
·
O
2

_

production in the endothelial tissue of untreated OSA patients. The BH4 effect on
·
O
2

_

and NO was more in OSA patients before treatment than after treatment (Figure). This indicates BH4 deficiency is important for VED in OSA patients.

Conclusions:
Thus BH4 deficiency occurs in VED in OSA and BH
4
supplementation can restore eNOS function conferring protection with reduced oxidative stress. Future clinical studies are warranted to evaluate BH4 supplementation in normalization of ED in OSA.
Abstract 273: A Blinded Evaluation of Combination Drug Therapy for Prolonged Ventricular Fibrillation Cardiac Arrest
Authors: Mader Timothy J , Coute Ryan A , Millay Scot A , Jensen Lennard C , Misiaszek Richard , Kellogg Adam R
Published: April 2024

Background
: There are many examples of medical disease treatment innovating from single agent, failure-based, serial medication delivery to first-line combination drug therapy. Could the same approach improve outcomes in the metabolic phase of VF?

Objective:
Using a swine model of prolonged VF, we compared ROSC and 20-minute survival in animals treated with single agents given in series to animals provided first-line combination drug therapy.

Methods
: The study was IACUC approved. Eighty swine (25-30 kg) were surgically instrumented under anesthesia, and VF was electrically induced. After 12 minutes of untreated VF, animals were 2:1 block randomized to 1 of 2 resuscitation schemes. SERIES (n=53) received: epinephrine (0.01 mg/kg [SDE]); vasopressin (0.57 mg/kg); amiodarone (4.3 mg/kg) and SDE; sodium bicarbonate (1 mEq/kg) and SDE - each delivery punctuated by a RS after 3 minutes of CPR. If ROSC occurred after any RS, supportive care was provided and subsequent medications were not given. COCKTAIL (n=27) received all drugs together (with metoprolol [0.2 mg/kg]), followed by CPR and RS1. A SDE followed each failed RS. All drugs were given IV with a flush. CPR and RS attempts were standardized. Resuscitation continued until ROSC was achieved or 20 minutes elapsed without ROSC. Group comparisons were assessed using descriptive statistics. Proportions with 95%CI were calculated for VF termination, ROSC, and survival.

Results
: At baseline, the two groups were similar. The figure summarizes our findings. SERIES outcomes mirrored historical controls.

Conclusion
: In this swine model of prolonged OHCA, short-term outcomes were adversely affected by this drug/dosage combination.
Abstract 283: Barriers to Calling 911 and Performing Cardiopulmonary Resuscitation in High-Risk Neighborhoods in Denver
Authors: Sasson Comilla , Ramirez Lorenzo , Medrano Mandy , Medina Christopher , Tafoya-Dominguez Beverly , Nassel Ariann , Padilla Ricardo
Published: April 2024

Background:
Previous research in Denver, CO identified five high-risk neighborhoods where the incidence of OHCA (out-of-hospital cardiac arrest) is high and bystander cardiopulmonary resuscitation (CPR) is low. The neighborhoods are comprised primarily of Latino and African-American residents with a median household income of <$35,000.

Objectives:
1) To identify barriers to calling 911 and performing CPR neighborhoods in Denver’s high-risk neighborhoods. 2) To understand people’s familiarity with and opinions about hands-only CPR as compared to traditional CPR.

Methods:
Six focus groups and nine key informant interviews were conducted between August 2011 and March 2012 the five high-risk Denver neighborhoods. We utilized purposeful and snowball sampling to recruit 64 participants. A qualitative study design using grounded theory was used to develop codes, categories and themes in an iterative process. The focus groups were audiotaped and transcribed verbatim. Two reviewers independently read through each transcript and developed a conceptual framework.

Results:
Demographics of the participants are listed in Table 1. Six main thematic areas were identified as barriers to calling 911 for residents: cost incurred by victim/victim’s family, undocumented status, fear of getting involved, unsure of what an emergency situation is, language barriers, and cultural issues. Eight main thematic areas were identified as barriers to performing CPR: legal ramifications, fear of doing CPR incorrectly, fear of breathing into someone else’s mouth, fear of hurting victims, being too old to do effective CPR, panic, undocumented status and a lack of resources on CPR in Spanish.

Conclusion:
We identified significant cultural and language barriers to calling 911 and performing CPR. Future work will be conducted with residents from these neighborhoods to design and implement a community-based intervention that will overcome these barriers.
Abstract 307: Transmission of Prehospital 12-Lead ECGs Significantly Reduces Time of Emergency Department Arrival to Arrival in the Angiography Suite and Door-to-Balloon Time in Patients with a STEMI
Authors: Jorolemon Michael R , Plis Lorissa , Sigona Karen , Allain Michael , Pikarsky Rob , Surprenant Susie , Hogue Troy , Johnson Lynette
Published: April 2024

Background:

Studies have shown that EMS obtained pre-hospital 12 Lead ECG’s have a positive impact on the treatment and mortality of patients experiencing an acute myocardial infarction. Many PCI centers do not have cardiac angiography staff in house 24/7. The response and prep time to bring an angiography suite to functional readiness is at least 20 minutes during the off hours.

Objective:

To assess our hypothesis that transmission of the pre-hospital 12 Lead ECGs decreases door to balloon time for patients experiencing a STEMI and decreases time spent in the Emergency Department.

Methods:

All STEMI patients that presented via EMS to an urban Hospital between January 1, 2010 and December 31, 2011 and went to the cardiac angiography suite were reviewed. Analysis was performed to investigate the relationship on door to balloon time and time spent in the Emergency Department between transmissions vs. non-transmission of the pre-hospital 12 lead ECG.

Results:

Of all STEMI patients that presented via EMS in 2010 - 2011 (N=83), 59.0% had a pre-hospital notification of the STEMI resulting in an average door to balloon time of 36.4 minutes (p-value of 0.0008). The STEMI patients that arrived via EMS without transmission of the 12 Lead ECG had a longer average door to balloon time of 53.2 minutes (p-value of 0.0004). There was not a statistical difference in the average EMS on scene time between the groups (11 minutes for the transmission group and 13 minutes for the non-transmission group). There was a 28.1 minute reduction in the time of arrival in the Emergency Department to arrival in the angiography suite time for the patient in which a pre-hospital 12 Lead ECG was transmitted (9.9 minutes for the transmission group vs. 38.0 minutes for the non-transmission group, p-value of 0.000002).

Conclusion:

Transmission of the pre-hospital 12 Lead ECG for patients experiencing a STEMI significantly decreases the time from arrival in the Emergency Department to arrival in the angiography suite and decreases the overall door to balloon time for those patients. The time saved with transmission of the pre-hospital 12 ECG for patients experiencing a STEMI facilitates by-passing the Emergency Department, allowing a STEMI patient to go directly to the cardiac angiography suite.
Abstract 18765: PAR-1 Contributes to the Innate Immune Response to Viral Infection
Authors: Antoniak Silvio , Owens Albert P , Williams Julie C , Lee Rebecca D , Weithäuser Alice , Baunacke Martin , Sheridan Patricia A , Malz Ronny , Pawlinski Rafal , Blaxall Burns , Beck Melinda A. , Rauch Ursula , Mackman Nigel
Published: April 2024

Silvio Antoniak, 2012 Finalist and Presenting Author
Abstract 13139: Prognostic Utility of Contrast-Enhanced Cardiovascular Magnetic Resonance Imaging in Hypertrophic Cardiomyopathy: An International Multicenter Study
Authors: Chan Raymond H , Maron Barry J , Olivotto Iacopo , Assenza Gabriele , Lesser John R. , Haas Tammy , Gruner Christiane , Crean Andrew , Rakowski Harry , Udelson James E. , Rowin Ethan , Tomberli Benedetta , Spirito Paolo , Formisano Francesco , Biagini Elena , Rapezzi Claudio , Cecco Carlo Nicola De , Autore Camillo , Cook Earl Francis , Hong Susie N , Gibson C. Michael , Manning Warren J , Appelbaum Evan , Maron Martin S
Published: April 2024

Raymond H Chan, 2012 Finalist and Presenting Author
Abstract 12921: Left Atrial Dysfunction and Cryptogenic Stroke: Novel Insights from Transthoracic Echocardiography
Authors: Leong Darryl P , Joyce Emer , Debonnaire Philippe , Katsanos Spyridon , Schalij Martin J , Holman Eduard R , Bax Jeroen J , Delgado Victoria , Marsan Nina Ajmone
Published: April 2024

Darryl P Leong, 2012 Finalist and Presenting Author
Abstract 56: Variability in Patient Selection Criteria for Postarrest Protocols
Authors: McNicol Donald R , Camp-Rogers Teresa R , Kurz Michael C
Published: April 2024

Introduction

The prevalence of therapeutic hypothermia (TH) for post-cardiac patients has yet to be established. Complicating this measure is the lack of standardized, universal recommendations on patient selection criteria for.TH. The objective of this study is to assess the amount of variability in patient selection criteria.

Methods

We conducted a systematic search of all publicly available TH protocols from published Internet sources. Protocols must be complete, associated with a hospital, and demonstrate clear patient selection criteria, to be included. The proportion of hospitals that considered each patient selection criteria was determined. Only descriptive statistics were provided. No statistical inferences were made.

Results

A total of 64 TH protocols were assessed. Among the protocols, the patient selection criteria are viewed as Utstein based or non-Utstein based (Table 1). The Utstein variables considered were initial rhythm, witnessed, location, time to BLS, and age. Non-Utstein variables included were total ischemic time, time since ROSC, baseline body temperature, etiology of arrest, and hemodynamic parameters. The widest variability was noted in the category of “hemodynamic parameters.” Some hospitals (0.19) eliminate any patients with subjective evidence of “shock or instability.” Other hospitals vary in consideration of systolic blood pressure (0.44) or mean arterial pressure (0.27) to determine eligibility.

Conclusion

The results of this observational study indicate wide variability in the patient selection criteria for post-arrest protocols. The criteria provide stricter selection criteria than international guidelines recommend. Inconsistently applied criteria may exclude patients who would benefit from treatment. The impact of patient selection criteria could have an effect on measured national survival rates and outcomes.
Abstract 57: A Crowdsourcing, Mobile Media, Challenge to Locate Automated External Defibrillators
Authors: Merchant Raina M , Asch David A , Hershey John C , Griffis Heather , Hill Shawndra , Saynisch Olivia , Leung Alison , Asch Jeremy M , Lozada Kirkland , Vetter Victoria , Nadkarni Lindsay , Branas Charles C , Stone Eric , Starr Larry , Nichol Graham , Becker Lance B
Published: April 2024

Background:
Automated external defibrillators (AEDs) are potentially life saving devices located in public locations, but are hard to find and rarely used. Crowdsourcing is increasingly being used to engage the public to participate in tasks that involve surveillance and mapping. Less is known however about using crowdsourcing for collecting important health data, like AED locations--where data validity is critical.

Methods:
We used a crowdsourcing challenge to identify AEDs in Philadelphia. Participants in the challenge had to be >18 years of age. A custom mobile app was used to photograph AEDs and enter information about device location and access. Monetary prizes were offered to incentivize participation. Data validity was assessed by matching the mobile phones’ associated GPS coordinates of the photo with the GPS coordinates of the building location and/or comparing submitted data with AED location information collected pre-challenge.

Results:
In 8 weeks, 1429 AEDs were submitted by 313 teams and individuals. Of participants providing demographic information (n=203), most were students 59(31%) or in the medical field 42(22%). Older participants (>41 years old) submitted more AEDs than younger participants (18-40 years of age) (respectively, 1025 vs. 404, p<.01). Most participants resided in Philadelphia 129 (64%), while others represented 10 states and 3 countries. More than half of the submissions represented unique AEDs 852(60%) in 528 buildings. AEDs were identified throughout the city, in 94% (46/49) of all Philadelphia zip codes in both public (59%) and private (41%) locations. Buildings (n=528) reported with AEDs were primarily: gyms 102 (19%), schools 85 (16%), and offices 57 (11%). Most submissions 1114 (75%) were validated with photo GPS coordinates matching the reported buildings GPS coordinates or by comparing submissions with data of AED locations identified pre-challenge.

Conclusion:
Crowdsourcing is a feasible approach for identifying AED locations in an urban city. Further, mobile GPS technology can be used for validating health data provided by the public. Engaging the public as “citizen scientist” can help identify emergency health resources and needs and can simultaneously improve awareness about them.
Advancement of Medical Knowledge: Lessons Learned From the Past
Authors: Sellke Frank
Published: April 2024

Since the days of Hippocrates and Galen, medical knowledge has expanded at a seemingly exponential rate. While many of the early discoveries have stood the test of time, many of the early and even recent “advances” have been found to be totally incorrect. Unfortunately, this not only results in the publication of inaccurate data, but may lead to incorrect assumptions, ineffective directions for further research, and in the end, negative or harmful clinical trials and therapies for the treatment of human illnesses based on false information. How can we decrease the likelihood that false information will be propagated? One way is to consider that all scientific knowledge, even well established dogma, is not necessarily correct. Another way is to acknowledge that one study does not prove anything. Furthermore, it is often the case that an incorrect conclusion is not due to incorrect data, but misinterpretation of the data. As it has been demonstrated on many instances, acceptance of knowledge as irrefutable fact can set back science decades or in some cases centuries. How can we prevent the propagation of inaccurate, irreproducible or fabricated information? One must be skeptical of all scientific findings, and especially clinical findings. Even those seemingly well established may in the future be found to be wrong. Data derived from in vitro or animal experiments may be interesting and potentially important, but should reflect what happens clinically. Finally, just because someone is an expert, does not mean that person is correct. Having healthy skepticism of all scientific findings may prevent the propagation of incorrect information and optimize overall scientific advancement.
Abstract 68: Incidence and Outcomes of Unresolved Prehospital Rearrest in EMS-Treated Cases of Out-of-Hospital Cardiac Arrest
Authors: Salcido David D , Koller Allison C , Sundermann Matthew L , Callaway Clifton W , Menegazzi James J ,   The ROC Investigators
Published: April 2024

Background: The phenomenon of re-arrest (RA) - loss of pulses after successful return of spontaneous circulation (ROSC) - is of interest in resuscitation research because even transient loss of pulses prior to hospital arrival may have a detrimental impact on patient outcomes. Patients who experience RA may also demonstrate specific pathology, the identification and treatment of which may lead to better outcomes.

Objective: Estimate the incidence and outcomes of one manifestation of RA, unresolved prehospital-RA (UP-RA), wherein pulses are not reestablished following at least one RA prior to arrival at the emergency department (ED).

Methods: Case data spanning 2006-2008 were obtained from the Resuscitation Outcomes Consortium, a multisite clinical research consortium with cardiac arrest surveillance programs in 10 sites in North America. Non-traumatic emergency medical services (EMS)-treated cases of out-of-hospital cardiac arrest (OHCA) with any instance of prehospital ROSC were included. Prehospital ROSC events, patient vital status at ED admission, survival to hospital discharge, patient demographics, and ancillary resuscitation variables were ascertained through review of paramedic-generated patient care reports (PCRs), defibrillator data downloads, and hospital records. Prehospital ROSC was defined as a detectible return of pulses resulting in an obvious suspension of CPR. UP-RA status was assigned to any case with prehospital ROSC that did not have pulses upon ED arrival.

Results: Out of 18,937 cases of OHCA across all sites, there were 11,456 (60.5%) EMS-treated cases. Prehospital ROSC was found in 4,609 (40.2%) cases. Of these cases, mean(SD) age was 63.7(17), 37.1% were female, 21.5% occurred in public, 13.5% were EMS witnessed, and overall survival to hospital discharge was 28%. Vital status at ED was available for 3,116 (67.6%) cases of which UP-RA was present in 473 (15.2%). Survival was 7.8% in cases with UP-RA, compared to 33.3% in cases without, and UP-RA was directly associated with death prior to hospital discharge (OR: 6.14, CI: 4.31-8.75, p<0.001).

Conclusion: When characterized as an irreversible event prior to ED arrival, incidence of RA is relatively uncommon but strongly predictive of non-survival at hospital discharge.
Abstract 82: Chest Stiffness and Force-Depth Relations Change Over Time During Prolonged CPR: An Animal Model
Authors: Aelen Paul , Paulussen Igor , Ordelman Simone , Noordergraaf Gerrit-Jan , Woerlee Pierre
Published: April 2024

INTRODUCTION

Chest deformation during CPR results in increased intrathoracic pressure and blood flow. A parameter linked to both deformation and internal pressures is reaction force. However, little is known about the time dependence of the force-depth relationship. In this study we assessed the hypothesis that chest stiffness and force-depth relations change during CPR in a pig model.

MATERIAL AND METHODS

Fourteen Yorkshire pigs with an average AP diameter of 20 cm were anesthetized after which ventricular fibrillation (VF) was induced. CPR was administered for 21 minutes at compression depths of 5 cm at frequencies of 80-120cpm during which absolute depth and force were measured continuously. The force-depth signal was divided into elastic and viscous components. Corrections were made for incomplete recoil. Chest stiffness was defined as the maximum force for each compression divided by its corresponding depth. Curvature and stiffness over time were studied.

RESULTS

The force versus depth relation shows that at the start of CPR the relationship is almost linear. As compressions continue, the curve becomes more curved. Chest stiffness starts at relatively high values of 118 +/- 28 N/cm which decreased to 96 +/- 19 N/cm of the original values after 250 compressions. After this point in time only minor changes in stiffness and nonlinearity were observed.

CONCLUSION

In conclusion, chest stiffness decreases and the force depth relation changes from linear to convex during CPR. Changes take mostly in the initial phase, where after they approach steady state. This is relevant for obtaining adequate blood flow during CPR.
Abstract 84: Relationship Between Chest Compression Rate and Depth During Cardiopulmonary Resuscitation
Authors: Babaeizadeh Saeed , Firoozabadi Reza , Helfenbein Eric , Daya Mohamud
Published: April 2024

Background
The 2010 AHA guidelines for healthcare providers encourage rescuers to focus on the delivery of high quality cardiopulmonary resuscitation (CPR). For adults, guidelines recommend chest compressions at a rate of at least 100 compressions per minute (cpm) with a depth of at least 51 millimeters (mm). Continuously pushing the chest hard and fast can be difficult and the compression depth may drop if the rescuer increases the compression rate.

Objective
Determine the distributions of and relationship between chest compression rate and depth during CPR in out-of-hospital cardiac arrest (OHCA) patients.

Methods
Recordings from a convenience sample of 234 OHCA patients with compression waveforms collected from 2006 to 2010 from a single EMS agency using the Philips HeartStart MRx defibrillator. Real-time audio and visual feedback was available to EMS personnel based on the 2005 depth guidelines (38 to 51 mm). Compression depth and rate were calculated based on the waveforms recorded by the Q-CPR
TM
measurement and feedback tool. The continuous distributions of rate and depth were generated using only the segments with good signal quality (total of 42 hours).

Results
The figure shows the distributions of and relationship between the rate and depth. In this dataset, 69% of the time the compression rate was at least 100 cpm and 48% of the compressions had a depth between 38 and 51 mm. Only 10% were performed slower than 90 cpm, and only 12% were less than 30 mm deep. With the compression rates between 73 to 88 cpm, the depth increased at a rate of 0.3 mm/cpm. However, at compression rates faster than 88 cpm, the depth decreased at almost the same rate of -0.3 mm/cpm.

Conclusion
Chest compressions at rates faster than 88 cpm are associated with a reduction in depth. The practical balance between compression rate and depth deserve consideration in the Guidelines process.
Abstract 86: Existing Research Is Inadequate for the Development of Guidelines for the Basic Life Support Management of Airway Obstruction in Adults: Results of a Systematic Review
Authors: Bradley Richard ,   American Red Cross Scientific Advisory Council
Published: April 2024

Introduction: There has been considerable controversy and several changes in guidelines for the basic life support (BLS) management of choking since the introduction of the Heimlich procedure in 1974.

Hypothesis: The objective of this project was to conduct a structured literature review to answer the question, “For adults, either conscious or unconscious, with obstructed airway, does any specific resuscitation techniques compared to currently recommended techniques, lead to different outcomes?”

Methods: We searched MEDLINE using a complex search criterion. We performed further searches on the basis of articles cited in references and by using the ‘Cited by’ function in Google Scholar. We included articles if they addressed a therapy for choking in adults. We excluded articles if they addressed only pediatric patients, if there was no comparison group, or if the skills involved were beyond BLS. We collected data using a standardized study selection and data extraction form. This included specific criteria to grade the level of evidence (LOE) and quality of each paper.

Results: We identified 475 records after duplicates were removed; we screened all of these and excluded 454. This left 22 full-text articles which we assessed for eligibility; we excluded 19 of these, leaving 3 studies that we included in qualitative synthesis. Of these, data from one fair quality LOE 3b study suggests that peak airway pressures developed by chest compressions are significantly higher than the pressure from abdominal thrusts. Data from one poor quality LOE 4 study suggests that for conscious adults with an obstructed airway, abdominal thrusts generate higher peak airway pressures when delivered when the victim is supine as compared to seated and that back blows do not generate any significant change in airway pressure. We could not identify any other papers that compared BLS techniques for managing obstructed airways in adults. Clearly, there is a dearth of evidence to support basic life support treatment guidelines for this important problem.

Conclusions: In conclusion, rescuers attempting to resolve a complete airway obstruction in a conscious or unconscious adult should provide abdominal thrusts or chest compressions.
Abstract 87: Duration of Longest Chest Compression Interruption Predicts Poor Cardiac Arrest Survival Independent of Chest Compression Fraction
Authors: Brouwer Tom F , Walker Robert G , Chapman Fred W , Koster Rudolph W
Published: April 2024

Background

Long pauses in chest compressions (cc) are thought to be harmful. However, prior clinical analyses have only evaluated peri-shock pauses (PSP) of the first 1 - 3 shocks, or cc fraction over the first few minutes of the resuscitation. We analyzed full recordings from a large cohort of resuscitations to explore relationships between long PSPs, long pauses for other reasons (non-PSP), and survival.

Methods

In an observational study of prospectively collected data, we enrolled all patients with cardiac cause out-of-hospital cardiac arrest presenting with VT/VF during calendar year 2009 in five EMS systems. Continuous ECG and impedance recordings from all defibrillators (AED and manual) used during resuscitation were analyzed to measure longest PSP (longest interval without cc containing a shock), and longest non-PSP (longest interval without cc prior to the last shock, and not containing a shock). Because pause durations are inversely related to cc fraction, we also measured cc fraction over the entire resuscitation.

Results

In 319 enrolled patients, survival rate was 38% and CC fraction was median (IQR) 79% (71%, 84%). Longest PSP was 26 (16, 42) sec and longest non-PSP was 24 ( 11, 38) sec. Both the longest PSP [Odds Ratio (OR) = 0.91 per 5 sec increment (0.86, 0.97)] and the longest non-PSP [OR = 0.84 (0.76, 0.92)] were significantly associated with survival to discharge in a multivariate regression model adjusting for recognized Utstein predictors. These significant associations did not change when additionally adjusted for cc fraction. In 36% of patients, the longest non-PSP was ≥ the longest PSP. Survival was significantly lower in this group than in the 64% of patients where the longest PSP was longer than any non-PSP (27% vs 44%, p=0.004), despite a higher median CC fraction (80% vs 77%, p=0.04).

Conclusions

Prolonged cc pauses have a significant negative association with survival that is not explained by chest compression fraction. The longest non-PSP had a lower odds ratio for survival than the longest PSP, and it was the longest pause prior to the last shock in more than a third of the cases. Avoiding long pauses for interventions other than defibrillation may be even more important than minimizing PSPs or further increasing chest compression fraction.
Abstract 8897: Valid Cardiac Strategy for Reversing Focal Cerebral Ischemia Caused by Vasospasm after Subarachnoid Hemorrhage
Authors: Mutoh Tatsushi , Kobayashi Shinya , Ishikawa Tatsuya , Suzuki Akifumi
Published: April 2024

Delayed cerebral ischemia (DCI) attributable to vasospasm is currently the leading cause of death and disability after subarachnoid hemorrhage (SAH). Therapeutic hemodynamic augmentation by increasing cardiac output (CO) is a valuable method for elevating cerebral blood flow and oxygenation in dysautoregulated territories affected by DCI. Our previous results suggest that the key for successful reversal of focal ischemia is to accomplish hemodynamic acceleration enough to improve cerebral microcirculation. We prospectively assessed more effective strategy for hyperdynamic therapy with dobutamine (DOB) either by intermittent dose-repetition or by continuous step-wise dose increments in the treatment of post-SAH DCI. Real-time CO and regional cerebral oxygenation (rSO
2
) recordings during the therapy in conjunction with the assessment of neurological improvements were analyzed. Forty patients with SAH treated surgically within 24 hours of ictus and diagnosed to have DCI between postoperative days 4 and 14 were enrolled. DOB was administered at an initial dose of 3 µg/kg/min and then increased in 3 µg/kg/min increments until resolution of the neurologic symptoms. Once the DCI recurred, 1) the DOB dose was reduced to the level where CO and rSO
2
became stable to apply the same dose-repetition (LD) or 2) simply increased the same increments until maximal dose (18 µg/kg/min) (HD). A total of 158 DOB challenges were performed with a maximum therapeutic dose of 9 ± 3 µg/kg/min (LD) and 13 ± 4 µg/kg/min (HD) (p=0.001), respectively. In response to DOB, uptake and stabilization of rSO
2
accompanied by a rapid elevation of CO usually occur, followed by improvement of the symptoms. Calculated peak slope of the CO uptake were greater in LD than in HD (p<0.05). Area under the ROC curve of peak CO slope to discriminate neurological responders for each challenge was not significantly different between the strategies (p>0.05). Patients managed with LD experienced less numbers of tachycardia, arrhythmia and paralytic ileus than those with HD.

In conclusion, repeat application strategy with low-dose DOB will play a key role of hyperdynamic therapy in effectively relieving focal ischemia with less drug-induced complications in patients suffering from DCI after SAH.
Abstract 8980: Investigating Left Ventricular Torsion with 4-Dimensional Echocardiography
Authors: Ohnemus Daniella , Panosian Jill , Houle Helene , Ashraf Muhammad , Sahn David J
Published: April 2024

Background:
We investigated the relationship between left ventricular (LV) torsion, strain and stroke volume (SV) using a new 4-dimensional (4D) echocardiography strain and mechanics program developed by Siemens.

Methods:
We used an in vitro rotation model capable of producing torsion and longitudinal strain in 3 freshly harvested pig hearts, which were secured on a pump phantom in a water bath with the apex fixed and the base rotated 0°, 10° and 20° at SVs of 40, 50, 60 and 70 ml. 4D image loops were obtained on a Siemens Acuson SC2000 ultrasound system using a 4Z1C matrix probe.

Results:
As degrees of rotation increased, computed apical and basal rotation increased accordingly. There was no strong correlation between computed rotation and SV. The Siemens 3D mechanics program computed slight degrees of rotation at both the apical and basal levels, even when the phantom control system was set to 0° rotation.

Conclusions:
The apparent rotation measured when the rotator was set to 0° supports the hypothesis that rotation is intrinsic and originates from the helical orientation of the myocardial fibers. The 4D program tracked increasing LV rotation extremely accurately in our study.