Causes of Malfunction of Bioprostheses Inserted Percutaneously in the Aortic Valve Position in Patients Whose Native Aortic Valve Was Congenitally Bicuspid and Stenotic.

Transcatheter aortic valve implantation (TAVI) has brought in recent years relief of cardiac-induced symptoms to a large number of patients with aortic stenosis. Whether it is better to use TAVI for the treatment of aortic valve stenosis superimposed on a congenitally bicuspid valve has been debated in contrast to its proved usefulness in aortic valve stenosis involving a tricuspid aortic valve. From January 2020 to March 2023, surgical aortic valve replacement of TAVI valve and native aortic valve was done in 6 patients. The clinical findings of the patients and morphologic findings from the surgical specimens submitted to the cardiac pathology department were subsequently examined. All the 6 native aortic valves had bicuspid configuration. The TAVI valve in each patient was excised from 9 to 88 months (mean 36 months) after it had been implanted because of paravalvular leak in 4, severe stenosis of the prosthetic valve in 1, and bioprosthetic cuspal degeneration in 1. Prosthetic valve endocarditis was clinically suspected in 2 patients, but the specimen culture was negative. Before surgical aortic valve replacement, 3 patients experienced stroke after TAVI. All 6 patients had low hemoglobin levels (mean 9.5 mg/100 ml) and low hematocrit levels (mean 29.5%). Reticulocyte count was available in 4 patients and was increased in all (mean 3.5%). When the stenotic native aortic valve configuration is bicuspid, the raphe tends to be calcified first and located perpendicular to the flow of the blood and may prevent the ring of the caged bioprosthesis from being transferred to the aortic wall, which is a requirement for full opening of the lumen of the bioprosthesis. Thus, thorough consideration needs to be made before performing TAVI in patients whose native aortic valve is stenotic and bicuspid.