Cerebral Embolization Common Among Patients During Transcatheter Aortic Valve Replacement

Cerebral embolization was documented in approximately two-thirds of patients during transcatheter aortic valve replacement (TAVR) in the BRAVO-3 (Effect of Bivalirudin on Aortic Valve Intervention Outcomes-3) magnetic resonance imaging (MRI) substudy.

Researchers of the study also found no significant differences in cerebral embolization measures for intraprocedural anticoagulation during TAVR with bivalirudin compared to heparin, according to their findings, published in the Journal of the American College of Cardiology.

BRAVO-3 was a randomized trial that compared bivalirudin against unfractionated heparin in patients undergoing transfemoral TAVR. Researchers conducted a prospective cerebral MRI substudy across 4 sites to investigate the frequency of patients with ≥1 new cerebral embolus after TAVR, and to determine whether certain parenteral procedural anticoagulation strategies affect cerebral embolization.

A total of 60 patients underwent brain imaging with MRI after TAVR. Patients were randomly assigned to receive bivalirudin (n=29) or heparin (n=31). Baseline characteristics and use of antiplatelet medication did not differ significantly between the 2 groups.

The primary end point was defined as the proportion of patients with new cerebral emboli on MRI. Researchers also examined secondary end points including quantitative MRI analyses of cerebral lesions, and neurological outcomes at 48 hours and 30 days.

They found that the proportion of patients with ≥1 new cerebral embolus on MRI after TAVR did not differ between the bivalirudin and heparin groups (65.5% vs 58.1%; P=.55).

In the analysis comparing bivalirudin against heparin, there were also no significant differences in the number of emboli per patient (1; interquartile range [IQR]: 0-3; vs 1; IQR: 0-1; P=.08) or the total volume of emboli (45 mm³ [IQR: 0-175 mm³] vs 33 mm³ [IQR: 0-133 mm³]; P=.86). The proportion of patients with a clinical neurological deficit at 48 hours or at 30 days also did not differ between the 2 groups.

Researchers also noted that all patients who presented clinically with stroke showed evidence of a new emboli on the MRI. At 30 days, patients presenting with stroke had higher total volume of emboli, higher volume of single embolus per patient, and higher volume of the largest embolus per patient, compared with patients without stroke.

“This analysis from the BRAVO-3 MRI study, together with the findings from recent MRI studies, demonstrates the importance of dedicated MRI studies with high rates (>80%) of post-procedural MRI,” the authors noted.

“Patients presenting clinically with stroke showed evidence of new emboli on MRI, emphasizing the importance, and potential prognostic value, of these silent events, which needs to be further investigated in dedicated large-scale trials.”

Reference

Van Belle E, Hengstenberg C, Lefevre T, et al. Cerebral embolization during transcatheter aortic valve replacement: the BRAVO-3 MRI study. J Am Coll Cardiol. 2016. doi:10.1016/j.jacc.2016.05.006.