Response to letter regarding article, "Histopathology of embolic debris captured during transcatheter aortic valve replacement".

Transcatheter aortic valve replacement (TAVR) involves the introduction of a large-bore catheter system into a major artery or the left ventricle and the passage of guidewires, temporary pacemakers, balloons, and the valve-containing delivery system through the vascular bed to enable the delivery and eventual deployment of a previously crimped bioprosthesis in the aortic root. Appropriate anticoagulation is mandatory to minimize thrombus formation throughout the course of this relatively complex procedure. Fanning and colleagues, just as we were, are surprised by the relatively high thrombotic load captured in the embolic protection filters during TAVR. We reported suboptimal activated clotting times not reaching the intended target of 250 to 300 seconds that might have contributed to these findings.1 In our understanding, no consensus guidelines have so far formally recommended target activated clotting time levels >300 seconds. Indeed, the referenced American College of Cardiology Foundation/American Association for Thoracic Surgery/Society for Cardiac Angiography and Interventions/Society of Thoracic Surgeons expert consensus document on TAVR reads …