Right to Left Cardiac Shunt Detection (PFO Detection)

This study is currently recruiting participants. (see Contacts and Locations)
Verified December 2013 by Cardiox Corporation
Information provided by (Responsible Party):
Cardiox Corporation
ClinicalTrials.gov Identifier:
First received: January 8, 2013
Last updated: October 2, 2014
Last verified: December 2013

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 Intervention Phase
Right to Left Shunt
Patent Foramen Ovale
Atrial Septal Defect
Device: Flow Detection System
Phase 3

Study Type: Interventional
Study Design: Endpoint Classification: Safety/Efficacy Study
Intervention Model: Factorial 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

Further study details as provided by Cardiox Corporation:

Primary Outcome Measures:
  • 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

Secondary Outcome Measures:
  • 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.

Estimated Enrollment: 150
Study Start Date: November 2012
Estimated Study Completion Date: June 2015
Estimated Primary Completion Date: April 2015 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: TEE
Within patient comparison of TEE, FDS and a TCD from select study sites
Device: Flow Detection System
Other Name: Model 100


Ages Eligible for Study:   18 Years and older
Genders Eligible for Study:   Both
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.
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT01773252

United States, Alabama
University of Alabama, Birmingham Recruiting
Birmingham, Alabama, United States, 35249
Contact: Lynn Merritt, RN    205-975-7574    jlynnrn@uab.edu   
Principal Investigator: Andrei Alexandrov, MD         
United States, Arizona
Heart and Vascular Center of Arizona Recruiting
Phoenix, Arizona, United States, 85006
Contact: Aneta Scafaru, MD    602-628-8595    ascafaru@iri-az.com   
Principal Investigator: Nathan Laufer, MD         
United States, California
Alliance Research Centers Recruiting
Laguana Hills, California, United States, 92653
Contact: Justin Deck, CCRC    949-306-6669    jdeck@socsurgeons.com   
Principal Investigator: Ken Deck, MD         
UCLA Medical Center Recruiting
Los Angeles, California, United States, 90095
Contact: Ruby Gevorgyan, MD    310-794-4797    rgevorgyan@mednet.ucla.edu   
Principal Investigator: Jonathon Tobis, MD         
United States, Colorado
University of Colorado Recruiting
Aurora, Colorado, United States, 80045
Contact: Gwen Mauer    303-724-2097    HEATHER.MAURER@UCDENVER.EDU   
Principal Investigator: Michael S Kim, MD         
United States, Illinois
Rush University Medical Center Recruiting
Chicago, Illinois, United States, 60612
Contact: Karla Hanson, MS    312-942-6620    Karla_Hanson@rush.edu   
Principal Investigator: Damien Kenny, MD         
United States, Massachusetts
Tufts Medical Center Recruiting
Boston, Massachusetts, United States, 02111
Contact: Pari Fariborz    617-462-4965    PFariborz@tuftsmedicalcenter.org   
Principal Investigator: David Thaler, MD, PhD         
United States, New York
Columbia University Medical Center Recruiting
New york, New York, United States, 10032
Contact: Yasir Qureshi, MD    212-342-3486    yhq2001@columbia.edu   
Principal Investigator: Robert Sommer, MD         
United States, Ohio
Riverside Hospital Recruiting
Columbus, Ohio, United States, 43214
Contact: Chris Belcher, RN, BSN    614-566-1214    CBELCHE3@OhioHealth.com   
Principal Investigator: Kanny Grewal, MD         
United States, Texas
Methodist DeBakey Heart and Vascular Center Recruiting
Houston, Texas, United States, 77030
Contact: Zsolt Garami, MD    713-829-6678    ZGarami@tmhs.org   
Principal Investigator: Zsolt Garami, MD         
United States, Washington
Swedish Medical Center Recruiting
Seattle, Washington, United States, 98122
Contact: Colleen Truva, RN, BSN    206-215-3982    Colleen.Truva@swedish.org   
Principal Investigator: Mark Reisman, MD         
Sponsors and Collaborators
Cardiox Corporation
  More Information

No publications provided

Responsible Party: Cardiox Corporation
ClinicalTrials.gov Identifier: NCT01773252     History of Changes
Other Study ID Numbers: FDS-0005
Study First Received: January 8, 2013
Last Updated: October 2, 2014
Health Authority: United States: Food and Drug Administration

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:
Foramen Ovale, Patent
Heart Septal Defects, Atrial
Cardiovascular Abnormalities
Cardiovascular Diseases
Congenital Abnormalities
Heart Defects, Congenital
Heart Diseases
Heart Septal Defects

ClinicalTrials.gov processed this record on March 26, 2015