Von Willebrand factor, paravalvular leak, and a new vista for TAVR

When Edward Heyde, a general practitioner, described the syndrome of gastrointestinal bleeding in the presence of aortic stenosis that bears his name (1), there is no way he could have known that his observations would open doors for a procedure that was completely inconceivable at the time of his writing. After several decades of search for a mechanism the group from Lille demonstrated that turbulent blood flow at a narrowed aortic valve leads to degradation of circulating levels of the adhesive macromolecule von Willebrand Factor (vWF), resulting in a bleeding diathesis that is correctable only by surgical replacement of the valve, which in turn leads to rapid restoration of circulating vWF levels (2). The same group recently reported that transcatheter aortic valve replacement (TAVR) had a similar effect. These mechanistic observations also have important diagnostic implications. The Lille investigators have now tied them to one of the major problems that continues to confound the field—paravalular leak following TAVR—by demonstrating that the previously observed coagulation defect continues in patients who have persistent aortic regurgitation after TAVR (3). Potentially, these findings have profound diagnostic utility.