Abstract TMP106: Pooled Analysis Of Five Randomized Trials Comparing Device Closure Of Patent Foramen Ovale After Stroke To Medical Treatment: Impact Of Residual Shunt On Stroke Outcomes

Abstract

Introduction: Patent foramen ovale (PFO) closure is effective for secondary stroke prevention in well selected patients. After device implantation some patients have residual shunting. There was no impact of incomplete closure on recurrent stroke risk in any of the trials but outcome rates are low with little power to detect an effect. Hypothesis: Patients with residual shunts after PFO closure have more recurrent strokes than those with complete elimination of shunting. Methods: We pooled individual patient data from 5 of 6 randomized clinical trials comparing medical therapy to PFO closure + medical therapy. Residual shunt data were not available for 1 trial. This analysis only includes PFO closure subjects. Hazard ratios (HR) and 95% confidence intervals (CI) were estimated with Cox proportional hazards regression, adjusted for age, sex, coronary disease, diabetes, hypertension, hyperlipidemia, prior stroke/TIA, smoking, index event (stroke vs TIA), hypermobile septum, shunt size (large vs small) and infarct location (superficial vs deep). Multiple imputation of missing values for adjusted variables was used. Results: Among 1475 patients treated with PFO closure and with non-missing residual shunt data, 149 (10%) had incomplete closure. The median time from procedure to shunt measurement was 204 days (25 th -75 th percentile, 181-722). In the complete closure group the primary endpoint of recurrent ischemic stroke occurred in 30 patients (2.3%; 95% CI 1.5-3.2%) compared to 4 (2.7%; 95% CI 0.7-6.7%) with incomplete closure. Unadjusted and adjusted HRs comparing incomplete vs complete closure were 1.37 (0.48, 3.92) and 1.69 (0.37, 4.95) respectively. The secondary endpoint of recurrent ischemic stroke, TIA, or vascular death occurred in 66 (5.0%; 95% CI 3.9-6.3%) patients with complete closure compared to 9 (6.0%; 95% CI 2.8-11.2%) without. Unadjusted and adjusted HRs were 1.26 (0.63, 2.54) and 1.39 (0.68, 2.83) respectively. Conclusions: Our pooled analysis of individual subjects after PFO closure from 5 of 6 relevant randomized clinical trials, showed no association between residual shunt and recurrent stroke events. This analysis was limited by low rates of residual shunt and recurrent events even in this large, combined dataset.