Assessment of long-term changes in subvalvular aortic stenosis in patients following transcatheter aortic valve implantation

BACKGROUND: The clinical course, pathophysiology, and therapeutic options for valvular and subvalvular (accompanied by hypertrophic cardiomyopathy, HCM) aortic stenosis are well known separately, but the rare combination of severe aortic stenosis (AS) and obstructive HCM presents great diagnostic and treatment challenges. The combination of these diseases during transcatheter aortic valve implantation (TAVI) is associated with significantly worse hospital outcomes, including cardiogenic shock, renal failure, and death. There is evidence that TAVI without prior treatment of left ventricular outflow tract obstruction leads to higher mortality due to exacerbation of subvalvular obstruction. AIM: To evaluate changes in hypertrophy of interventricular septum (IVS) in patients with a combination of AS and HCM following TAVI. MATERIALS AND METHODS: The observational, retrospective, single-center, non-randomized study included 20 patients with diagnosed severe AS, preoperative IVS thickness ≥15 mm, and the preoperative ratio of IVS and left ventricular posterior wall thickness ≥1.3, following TAVI. Mean and maximum follow-up periods were 33 and 92 months, respectively. The primary endpoint was decreased IVS thickness following TAVI as determined by echocardiography. RESULTS: The average age of patients was 72.4±5.5 years, more than half of the subjects were women. 60% of patients were diagnosed with coronary artery disease at the time of TAVI. Pre- and postoperative median IVS thicknesses were 17.7±2.2 and 14.4±3.2 mm, respectively. Long-term outcomes of TAVI included a significant decrease in hypertrophy of IVS (p=0.031) IVS thicknesses mainly decreased over the period up to 24 months after surgery. Cox regression analysis found that each year of patient’s age increased the risk of no postoperative decrease in IVS thickness after surgery by 12% every month. CONCLUSION: There was a statistically significant decrease in hypertrophy of IVS in patients who underwent TAVI. In most cases, IVS thickness decreased within 2 years after surgery. Each year of patient’s age increased the risk of no postoperative decrease in IVS thicknesses by 12% every month.