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Right to Left Cardiac Shunt Detection (PFO Detection)

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT01773252
Recruitment Status : Terminated (Business decision to perform a market withdrawal of the product)
First Posted : January 23, 2013
Last Update Posted : November 13, 2015
Information provided by (Responsible Party):
Cardiox Corporation

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").

Condition or disease Intervention/treatment Phase
Right to Left Shunt Patent Foramen Ovale Atrial Septal Defect Device: Flow Detection System Phase 3

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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 141 participants
Allocation: N/A
Intervention Model: Single Group Assignment
Masking: None (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
Study Start Date : November 2012
Actual Primary Completion Date : October 2015
Actual Study Completion Date : November 2015

Arm Intervention/treatment
Experimental: TEE
Within patient comparison of TEE, FDS and a TCD from select study sites
Device: Flow Detection System
Other Name: Model 100

Primary Outcome Measures :
  1. Presence or absence of shunt [ Time Frame: Five days ]
    To establish the sensitivity and specificity of the Cardiox FDS using transesophageal echocardiography (TEE) as the reference standard

  2. Adverse Events [ Time Frame: Five days ]
    To establish the safety of the Cardiox FDS device

Secondary Outcome Measures :
  1. Presence or absence of shunt [ Time Frame: Three days ]
    To establish the positive percent agreement and the negative percent agreement of Cardiox FDS procedure with a transcranial Doppler (TCD) from select study sites.

Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years and older   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

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.

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT01773252

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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
Sponsors and Collaborators
Cardiox Corporation
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Study Director: Michael W Jopling, MD Cardiox Corporation
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Responsible Party: Cardiox Corporation Identifier: NCT01773252    
Other Study ID Numbers: FDS-0005
First Posted: January 23, 2013    Key Record Dates
Last Update Posted: November 13, 2015
Last Verified: November 2015
Keywords provided by Cardiox Corporation:
paradoxical thromboembolism
interventional cardiology
obstructive sleep apnea
decompression illness
transesophageal echocardiography
transthoracic echocardiography
transcranial Doppler
power m Mode
indocyanine green dye
Additional relevant MeSH terms:
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Foramen Ovale, Patent
Heart Septal Defects, Atrial
Heart Septal Defects
Heart Defects, Congenital
Cardiovascular Abnormalities
Cardiovascular Diseases
Heart Diseases
Congenital Abnormalities