Right to Left Cardiac Shunt Detection (PFO Detection)
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").
Right to Left Shunt
Patent Foramen Ovale
Atrial Septal Defect
Device: Flow Detection System
|Study Design:||Endpoint Classification: Safety/Efficacy Study
Intervention Model: Single Group Assignment
Masking: Open Label
Primary Purpose: Diagnostic
|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|
- Presence or absence of shunt [ Time Frame: Five days ] [ Designated as safety issue: No ]To establish the sensitivity and specificity of the Cardiox FDS using transesophageal echocardiography (TEE) as the reference standard
- Adverse Events [ Time Frame: Five days ] [ Designated as safety issue: Yes ]To establish the safety of the Cardiox FDS device
- Presence or absence of shunt [ Time Frame: Three days ] [ Designated as safety issue: No ]To establish the positive percent agreement and the negative percent agreement of Cardiox FDS procedure with a transcranial Doppler (TCD) from select study sites.
|Study Start Date:||November 2012|
|Study Completion Date:||November 2015|
|Primary Completion Date:||October 2015 (Final data collection date for primary outcome measure)|
Within patient comparison of TEE, FDS and a TCD from select study sites
Device: Flow Detection System
Other Name: Model 100
Please refer to this study by its ClinicalTrials.gov identifier: NCT01773252
|United States, Arizona|
|Heart and Vascular Center of Arizona|
|Phoenix, Arizona, United States, 85006|
|United States, California|
|UCLA Medical Center|
|Los Angeles, California, United States, 90095|
|United States, Colorado|
|University of Colorado|
|Aurora, Colorado, United States, 80045|
|United States, Illinois|
|Rush University Medical Center|
|Chicago, Illinois, United States, 60612|
|United States, Massachusetts|
|Tufts Medical Center|
|Boston, Massachusetts, United States, 02111|
|United States, New York|
|Columbia University Medical Center|
|New york, New York, United States, 10032|
|United States, Texas|
|Methodist DeBakey Heart and Vascular Center|
|Houston, Texas, United States, 77030|
|United States, Washington|
|Swedish Medical Center|
|Seattle, Washington, United States, 98122|
|Study Director:||Michael W Jopling, MD||Cardiox Corporation|