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For patients with systemic hypoxia and patent foramen ovale (PFO), transcatheter closure of the defect reduces oxygen requirements while improving symptoms and evidence of right-to-left shunt. The single-center study was published online July 22, 2013, ahead of print in the American Journal of Cardiology.
Researchers led by Brett E. Fenster, MD, of the University of Colorado Denver (Aurora, CO), looked at 97 patients with chronic respiratory insufficiency who underwent PFO closure for treatment of dyspnea and hypoxia at their institution between 2004 and 2009.
Procedural success was 99%. PFO closure was performed using the following devices:
Clinical Success, NYHA Class Improvement
Clinical success was achieved in 70% of patients, with improvement in NYHA class seen in 51% (P < 0.001 vs. baseline) and decreased oxygen requirement seen in roughly one-third of patients (34%; P < 0.001 vs. baseline), including 4 in whom oxygen therapy was completely discontinued. Symptom improvement alone was seen in 18% of patients, which was not significant compared with baseline.
On multivariable regression analysis, there were 5 factors associated with increased or decreased likelihood of improvement in NYHA class but which did not affect clinical success after PFO closure (table 1).
Table 1. Predictors of NYHA Class Improvement After PFO Closure
OR (95% CI)
Moderate to Severe Shunt
Age (Per Decile Increase)
NYHA Class at Referral
In addition, moderate or greater exercise shunt predicted improvement in dyspnea (OR 3.8; 95% CI 1.1-17.5; P = 0.03), but not the composite endpoint of improvement in ≥ 1 NYHA class after closure, patient-reported reduction in dyspnea without a change in NYHA class, or a decreased supplemental oxygen requirement.
Using a modified Bruce treadmill protocol, exercise time on stress saline echocardiogram improved in 8 of 12 patients from an average of 483 to 495 seconds after PFO closure.
The authors postulate that “arterial oxygen saturation in our medically diverse patient population was a measure of overall cardiopulmonary status, and [right-to-left shunt] was responsible for a portion of the arterial desaturation. PFO closure may confer symptomatic benefit only with exertion or have an incremental improvement in arterial oxygen saturation without complete normalization.”
Improvement Occurs ‘On The Table’
In a telephone interview with TCTMD, Robert J. Sommer, MD, of Columbia University Medical Center (New York, NY), noted that “there are definitely patients who for a variety of reasons—tricuspid regurgitation, right ventricular infarct, and congenital heart disease affecting the right side of the heart—can have higher right or left atrial pressures and in the setting of a PFO, they’ll have a right-to-left shunt.”
When the PFO is closed, Dr. Sommer added, oxygen saturation occurs “immediately on the table . . . and patients feel dramatically better because they’re no longer short of breadth from hypoxemia.”
Such cases are relatively uncommon, he observed, and randomized trials have not been conducted to test PFO closure in this setting, “but there’s no reason to do them,” Dr. Sommer explained. “We know it works. The study proves a concept that we are very comfortable with, that closing a hole in this setting is beneficial to the patient.”
He pointed out that device type makes little difference in terms of clinical outcomes, nor does it matter if there’s any residual leak after closure. “In this study, they had a number of patients with residual leaks after closure, but you’ve reduced the amount of shunting so dramatically that they’re no longer hypoxemic,” Dr. Sommer said. “And it takes care of the problem long term because once the device is implanted, it endothelializes, so the skin basically grows over it.”