Does Patent Foramen Ovale Size Matter in Men and Women

University of Oregon

Status: Completed

Conditions: Patent Foramen Ovale

Study type: Observational

Funder types: Other

Identifiers

NCT03904277

04302018.049

Details and patient eligibility

About

A patent foramen ovale (PFO) is present in ~30% of the general population. The PFO has historically been considered to be trivial. However, recent work by the investigator's group and others has identified that, compared to individuals without a PFO, those with a PFO have worse pulmonary gas exchange efficiency, have a higher core body temperature, blunted ventilatory responses to chronic hypoxia and acute carbon dioxide and increased susceptibility to altitude illnesses such as acute mountain sickness, and high altitude pulmonary edema (Lovering, Elliott & Davis J Appl Physiol 2016). Specific to this application,subjects with a PFO may have worse pulmonary gas exchange efficiency because a PFO is a potential source of right-to-left shunt that will make pulmonary gas exchange efficiency worse. If true, then this may negatively impact exercise capacity and/or exercise tolerance. Further, in those with a PFO compared to those without, preliminary work from the investigator's lab indicates that there may be an effect of PFO size on pulmonary gas exchange efficiency. This is such that those with a large PFO (grade 3 or higher) display significantly worse gas exchange efficiency compared to those with a small (grade 2 or lower) or no PFO,even at low exercise workloads. Additionally, the investigators were curious as to whether there would be a sex effect, but due to logistical constraints, the investigators were unable to recruit an equal number of female and male subjects. Thus, in addition to the potential size effect on the investigators outcome measures, the investigators would like to build on this work by examining the potential effect of biological sex. Although a PFO has been traditionally considered to have a minimal impact of physiology and pathophysiology, emerging evidence suggests this may not be the case. The investigator's lab is focused on understanding how and why a relatively small hole in the heart (PFO) can have a relatively large impact on cardiopulmonary and respiratory physiology, and how these impacts may be based on the size of the PFO.

Enrollment: 28 patients

Sex: All

Ages: 18 to 40 years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• Men and women aged 18-40
• Known to have/not have a PFO.

Exclusion criteria

• Previous history of coronary artery disease(ischemic heart disease such as angina, heart attack, myocardial infarction).
• Failure of Modified Allen's Test in both hands.
• Currently taking medications or herbal supplements for any heart or respiratory disease that they cannot stop taking for 48 hrsprior to testing (seasonal allergy medication not included in exclusion medications).
• Lidocaine, nitroglycerine or heparin allergy.
• Women who are pregnant or trying to become pregnant.
• Previous history of any condition that would prevent the subject from performing cycle ergometer exercise (for exercise study only).

Trial design

28 participants in 3 patient groups

No PFO

Description:

Research subjects who present no evidence of PFO - IE no appearance of saline contrast microbubbles within 3 cardiac cycles

Small PFO

Description:

Research subjects who present evidence of having a small PFO or ASD - IE appearance of 1-11 saline contrast microbubbles within 3 cardiac cycles

Large PFO

Description:

Research subjects who present evidence of having a large PFO - IE appearance of 12+ saline contrast microbubbles within 3 cardiac cycles.