Anticoagulation and Cerebral Embolism in TAVR
What is the proportion of patients with new cerebral embolus after transcatheter aortic valve replacement (TAVR) and the effect of parenteral procedural anticoagulation strategies on cerebral embolization?
The BRAVO-3 randomized trial compared bivalirudin with unfractionated heparin in patients undergoing transfemoral TAVR. A prospective cerebral magnetic resonance imaging (MRI) substudy (BRAVO-3 MRI) was conducted in four sites; 60 patients were imaged with brain MRI after TAVR. The primary endpoint was proportion of patients with new cerebral emboli on MRI. Secondary endpoints included quantitative MRI analyses of cerebral lesions, and neurological outcomes at 48 hours and 30 days.
Patients were randomized to bivalirudin (n = 29) versus heparin (n = 31). The proportion of patients with new cerebral emboli on MRI did not differ between bivalirudin and heparin groups (65.5% vs. 58.1%; p = 0.55). Groups were similar for median number of emboli/patient (1 [interquartile range, 0–3] vs. 1 [0–1]; p = 0.08), total volume of emboli (45 [0–175] vs. 33 [0–133] mm3; p = 0.86), or proportion of patients with a clinical neurological deficit at 48 hours or 30 days. All patients who presented clinically with stroke had evidence of new emboli on MRI.
The authors concluded that cerebral embolization is documented in nearly two-thirds of patients during contemporary TAVR.
This study reports a high rate of clinically silent cerebral embolization after TAVR as reported in other trials, without demonstrating any benefit regarding procedural anticoagulation with bivalirudin versus heparin in reducing these events. Furthermore, these results suggest a potential link between silent emboli on MRI and post-procedural clinical stroke. Larger prospective studies are needed to compare the safety and efficacy of various antithrombotic drug regimens to reduce the risk of ischemic stroke in patients undergoing TAVR.
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