Macroscopic and microscopic features of surgically explanted transcatheter aortic valve prostheses

With the extended indications of transcatheter aortic valve (TAV) replacement (TAVR) to lower-risk patients, there is an increasing number of patients requiring surgical explantation of failed TAV. We sought to describe macroscopic and microscopic features of surgically explanted percutaneous aortic valve prostheses.

Preoperative and surgical characteristic of patients undergoing surgical explantation of TAV were retrospectively analyzed from 2007 to 2020. Surgical and pathologic features of these valves, and outcomes of the surgical valve replacement were described.

Out of 1764 patients who underwent a TAVR procedure, 21 were operated for TAV failure. Isolated or combined indications for surgery included: significant paravalvular leak (n = 15), delayed prosthesis migration (n = 5), significant increase of trans-TAV gradients (n = 6), and endocarditis (n = 3). Mean time elapsed between TAVR and explantations was 674.9 ± 803.9 days. Macroscopic lesions found on explanted percutaneous valves were severe adhesions to the aorta (n = 10), calcifications (n = 7), leaflet thrombosis (n = 4), and vegetations (n = 3). Except for patients with endocarditis, one or more pathological lesions were found in 15 patients. Pathology analyses on these valves showed fibro-calcific degenerations (n = 12), pannus formation (n = 9), and chronic inflammation (n = 3). One patient (4.8%) died after surgical explantation, and 13 (61.9%) had concomitant procedures. The survival rate at 1 year was 94.4%.

Microscopic findings of fibro-calcific leaflet degeneration, and pannus formation in addition to macroscopic calcification and thrombosis present early, (within a mean of 2 years) after TAVR. Further investigation with a higher number of patients and echocardiographic follow-up is warranted.