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 utilize a TAVI for treatment of aortic valve stenosis superimposed on a congenitally bicuspid valve has been debated in contrast to its proven usefulness in aortic valve stenosis involving a tricuspid aortic valve. From January 2020 to March 2023, surgical aortic valve replacement (SAVR) of TAVI valve and native aortic valve was done in 6 patients. Clinical findings of the patients and morphologic findings from the surgical specimens submitted to 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) after it had been implanted due to paravalvular leak in 4, to severe stenosis of the prosthetic valve in 1, and to bioprosthetic cuspal degeneration in 1. Prosthetic valve endocarditis was clinically suspected in 2 patients, but the specimen culture was negative. Prior to SAVR, 3 had stroke after TAVI. All 6 had low hemoglobin levels (mean 9.5 mg/dl) and low hematocrit levels (mean 29.5%). Reticulocyte count was available in 4 patients and was elevated in all (mean 3.5%). When stenotic native aortic valve configuration is bicuspid, the raphe tends to be calcified first and located perpendicular to the flow of 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 prior to TAVI in patients whose native aortic valve is stenotic and bicuspid.