Patent foramen ovale and hypercoagulability as combined risk factors for stroke

The presence of a patent foramen ovale (PFO) is associated with a high incidence of cryptogenic stroke. Hypercoagulable states contribute to venous thromboembolism. The combination of both conditions may greatly increase the risk of stroke, and may indicate the need for long term anticoagulation. This study aimed to determine the incidence of both risk factors (PFO and hypercoagulable state) in a cohort of patients admitted with the diagnosis of stroke. We performed a retrospective chart review of 2028 consecutive patients admitted to the Massachusetts General Hospital through the emergency room who received an initial triage diagnosis of cerebrovascular event between October 1, 1994 and March 17, 1999. Of the 645 patients who had an echocardiogram searching for atrial shunting, 172 (26.7%) had a documented PFO. Of 472 patients who had a hypercoagulability study, an abnormality was identified in 112 (23.7%). Of the 280 patients who had both procedures, 14 (5.0%) were found to have both a PFO and a hypercoagulation abnormality; this represents 17.3% (14/81) of the patients with PFO who underwent a hypercoagulability study. In comparison, 22.1% (44/199) of patients without PFO had a hypercoagulation abnormality. In our series, the incidence of PFO was comparable to that of other reported series. A hypercoagulation abnormality was detected in one fourth of patients who underwent a diagnostic study. The frequency of hypercoagulation abnormality was not higher among patients with a PFO compared to patients without one.