Clinical trial NCT01773252: Right to Left Cardiac Shunt Detection
Official title: A With-in Subject, Controlled Study to Determine the Sensitivity and Specificity of the Cardiox Flow Detection System for the Detection of Right-to-Left Cardiac Shunts Compared to Transesophageal Echocardiography and Transcranial Doppler Ultrasound
Study type: INTERVENTIONAL
Overall status: TERMINATED
Phase: PHASE3
Conditions: Right to Left Shunt
Patent Foramen Ovale
Atrial Septal Defect
Keywords: RLS
RTLS
PFO
ASD
shunt
cardiac
paradoxical thromboembolism
interventional cardiology
stroke
migraine
aura
obstructive sleep apnea
decompression illness
neurology
transesophageal echocardiography
TEE
transthoracic echocardiography
TTE
transcranial Doppler
ultrasound
TCD
power m Mode
indocyanine green dye
ICG
Valsalva
Lead sponsor: Cardiox Corporation
Sponsor class: INDUSTRY
First posted: 2013-01-23
Enrollment: 141
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: NA
Intervention model: SINGLE_GROUP
Primary purpose: DIAGNOSTIC

Brief summary: The purpose of this study is to evaluate the sensitivity and specificity of the Cardiox Flow Detection System (FDS) in identifying an intracardiac right-to-left shunt (RLS) compared to the results of transesophageal echocardiography (TEE).

RLS intracardiac shunts are associated with a number of clinically important syndromes including paradoxical thromboembolism (causing stroke or other systemic infarct), migraine headaches (particularly with aura), desaturation with obstructive sleep apnea, and decompression illness. From a research perspective, the detection of shunts in subjects with these types of syndromes is critical in helping to define the role of RLS in these disease processes. From a clinical perspective, shunt detection will be increasingly important in an era where interventional procedures for repairing cardiac defects are available for subjects determined to be at risk.

The currently accepted reference standard for detection of an intra-cardiac patent foramen ovale/atrial septal defect (PFO/ASD) RLS is a transesophageal echocardiography (TEE), a procedure that is invasive, uncomfortable, and requires conscious sedation.

Alternative options include transthoracic echocardiography (TTE) with injection of agitated saline (with and without Valsalva strain), a procedure that is far less sensitive than TEE due to the echocardiography imaging limitations seen in many adults.

Finally, transcranial Doppler (TCD) with injection of agitated saline (with and without Valsalva strain) is a newer entrant into this arena that does not require sedation or any invasive instrumentation.

The Cardiox Model 100 FDS utilizes an optical sensor positioned on the surface of the subject's skin at the scaphoid fossa of the ear. Next, a predetermined dose of an indicator dye, indocyanine green (ICG), is injected at a predetermined rate into a peripheral antecubital vein of the subject while the subject performs a breathing maneuver called a Valsalva maneuver. The exhalation by the subject into a mouthpiece connected to a pressure transducer via a flexible tubing extension, or its equivalent (ie, performing the Valsalva maneuver), is an essential step for all existing RLS detection methods. The Valsalva maneuver by the subject creates a pressure differential between the right and left sides of the heart. This Valsalva maneuver results in blood flow from the right side of the heart to the left side of the heart through an ASD, and/or causes a PFO, if present, to open, also allowing blood to flow directly from the right side to the left side of the heart without passing through the lungs (pulmonary vasculature) for oxygenation.

The Earpads, including their fluorescence sensor arrays (FSA), are used to measure the relative concentration (ie, fluorescence signal level) of ICG dye in the bloodstream as a function of time. If a premature inflection or peak occurs in the ICG dye concentration level at a time point prior to the rise and fall of the concentration associated with the main bolus of indicator, then a RLS is present in the heart. The amplitude of this premature ICG dye-dilution curve (referred to as "RLS-indicator dilution curve") is used to subsequently quantify the magnitude of the right-to-left shunt by ratiometrically comparing the amplitude of this RLS indicator dilution curve to the amplitude of the main indicator dilution curve associated with that portion of the injected ICG dye that follows the normal pathway from the right side of the heart, through the lungs, and into the left side of the heart (referred to as "normal indicator dilution curve").


Eligibility criteria: Inclusion Criteria:

* At least 18 years of age;
* Is currently scheduled (within five days of FDS) for a TEE study with agitated saline contrast (bubble study) or has had a TEE procedure with agitated saline contrast study (bubble study) within the previous 12 months;
* If the Subject has undergone a shunt closure procedure, the protocol related TEE must be conducted greater than 12 months post closure.
* Is able to read and understand the ICF and has voluntarily provided written informed consent;
* Subject is able to perform a successful Valsalva maneuver (obtaining a score of 3 stars) using the Cardiox FDS device.

Exclusion Criteria:

* Subjects with known allergy or sensitivity to ICG or to iodide contrast dye or iodides including medications with high iodine content;
* Pregnant women or nursing mothers;
* Subjects scheduled for a radioactive iodine uptake studies (eg, thyroid studies) within one week of completing this study.

Primary outcomes:
measure: Presence or absence of shunt
timeFrame: Five days
measure: Adverse Events
timeFrame: Five days
Secondary outcomes:
measure: Presence or absence of shunt
timeFrame: Three days
Other outcomes:
Locations:
city: Phoenix
country: United States
facility: Heart and Vascular Center of Arizona
state: Arizona
city: Los Angeles
country: United States
facility: UCLA Medical Center
state: California
city: Aurora
country: United States
facility: University of Colorado
state: Colorado
city: Chicago
country: United States
facility: Rush University Medical Center
state: Illinois
city: Boston
country: United States
facility: Tufts Medical Center
state: Massachusetts
city: New york
country: United States
facility: Columbia University Medical Center
state: New York
city: Houston
country: United States
facility: Methodist DeBakey Heart and Vascular Center
state: Texas
city: Seattle
country: United States
facility: Swedish Medical Center
state: Washington
Study officials:
affiliation: Cardiox Corporation
name: Michael W Jopling, MD
role: STUDY_DIRECTOR
References: