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PFO closure decreased stroke risk in patients with inherited thrombophilias
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WASHINGTON — Among patients with inherited thrombophilias on anticoagulant or antiaggregant therapies, patent foramen ovale closure was associated with a fivefold decrease in the risk for stroke events, according to data presented at the American College of Cardiology Scientific Session.
Evidence suggests that the incidence of cryptogenic stroke may be higher among patients with PFOs and inherited thrombophilias, but data on the preferred therapy and the outcomes of these patients have not been reported in the large, randomized clinical trials of PFO closure, Yonatan Buber, MD, of the Sheba Medical Center in Ramat Gan, Israel, said during a presentation.
To fill this knowledge gap, Buber and colleagues conducted a retrospective data collection study of 136 patients (mean age, 53 years; 42% women) with inherited thrombophilias who had PFOs and were previously seen at their coagulation clinic between 2007 and 2016. All were treated with antiaggregants or anticoagulation therapies, and median follow-up was 41 months.
The decision for anticoagulation vs. antiaggregant therapy was made by the treating hematologist, who was also a coagulation expert. The decision to close a PFO was made at the discretion of the treating cardiologist and neurologist. After the procedure, PFO closure was confirmed about 2 months later using transthoracic echocardiogram with agitated saline injection, Buber noted.
Antiphospholipid syndrome was the most common type of thrombophilia (31%), followed by Factor V Leiden (22%), prothrombin mutation (18%), protein S deficiency (15%), protein C deficiency (7%), MTHFR mutation (5%) and essential thrombocytosis (2%).
According to the results presented, anticoagulant therapy was used in 75% of the study population, all in the form of vitamin K antagonists, whereas 25% received antiaggregant therapy. About 17% of the study population experienced cerebrovascular accident (CVA) or transient ischemic attack before the beginning of retrospective follow-up, and 7% had a history of atrial fibrillation.
Overall, 63% of patients underwent PFO closure, all using disc closure devices, Buber reported. Prior CVA or TIA (22% vs. 6%; P = .02) and atrial septal aneurysm (21% vs. 10%; P = .06) were more common among those who underwent PFO closure vs. those who did not. However, there were fewer patients with a history of AF among those who underwent PFO closure vs. those who did not (5% vs. 12%; P = .03).
Among patients who underwent PFO closure, three complications occurred: one tamponade, one AF and one large groin hematoma. The researchers observed no residual leaks on follow-up transthoracic echocardiogram.
During follow-up, 17% of patients experienced an endpoint event, mainly in the form of CVA, Buber reported. Median time to endpoint occurrence was about 18 months and was longer for those who underwent PFO closure (21 months vs. 17.5 months; P = .05).
At 3-year follow-up, the cumulative probability of freedom from CVA or TIA was significantly lower for patients who did not undergo PFO closure, as compared with patients who did, according to Buber.
In multivariable analysis, PFO closure was associated with a fivefold decrease in the risk for experiencing CVA or TIA (HR = 0.18; 95% CI, 0.03-0.3), whereas prior CVA or TIA was associated with a fivefold increase in risk (HR = 5.4; 95% CI, 1.9-45.3).
“Indeed, the vast majority of patients who had a prior CVA or TIA and did not have their PFO closed experienced a CVA/TIA event,” Buber said.
Anticoagulation therapy was also associated with a twofold decrease in risk for CVA or TIA (HR = 0.47; 95% CI, 0.06-0.9), and atrial septal aneurysm was associated with about a twofold increase in risk (HR = 2.1; 95% CI, 0.93-0.39).
“These findings intrigued us, so we looked into the clinical scenarios in which these strokes occurred. What we found was that in 13 patients, or 57% of the stroke events in the study, strokes occurred in the vicinity of 1 month of anticoagulation or antiaggregant therapy interruption due to medical procedures,” Buber said. “All events occurred in patients who did not have their PFO closed, and this may be an important reason why PFO closure was so effective in our study population.”
The researchers observed no statistically significant differences in outcomes according to thrombophilia type, although numerically, the highest rates of CVA and TIA occurred among patients with the prothrombin mutation.
Buber acknowledged several study limitations, including its single-center, retrospective design; the fact that decisions regarding antiaggregant or anticoagulation therapy and PFO closure were made at the discretion of treating physicians; and a lack of full exploration of the etiology of the stroke events. – by Melissa Foster
Reference:
Buber Y. Abstract 903-06. Presented at: American College of Cardiology Scientific Session; March 17-19, 2017; Washington, D.C.
Disclosure: Buber reports no relevant financial disclosures.