Association between coronary flow and aortic stenosis during transcatheter aortic valve implantation

In patients with aortic stenosis (AS), the coronary flow reserve decreases even in the absence of epicardial coronary artery stenosis. Systolic coronary flow reversal (SFR) reflecting reduced coronary microcirculation, often seen in patients with severe AS, has a potential negative impact on the pathogenesis of cardiac dysfunction. However, there are limited data on the relationship between the severity of AS and SFR, as well as on the benefits of transcatheter aortic valve implantation (TAVI). The aim of this study was to evaluate the relationship between the severity of AS and efficacy of TAVI in improving SFR.

Consecutive patients with AS who had undergone TAVI using transoesophageal echocardiography (TEE) from November 2020 to February 2022 were prospectively enrolled. Coronary flow in the left anterior descending artery as well as the aortic valve peak velocities, and the mean aortic valve pressure gradients (AVPGs), indicating the severity of AS, were measured using intraprocedural TEE before and after TAVI. The following parameters were measured as coronary flow: systolic and diastolic peak velocity (cm/s) and systolic and diastolic velocity-time integral (VTI) (cm). SFR was defined as the presence of a reversal coronary flow component in systole. The enrolled patients were classified into two groups according to the presence or absence of SFR before TAVI. A total of 25 patients were included: 13 had SFR and 12 who had no SFR, before TAVI. Patients with SFR had significantly higher aortic valve peak velocities (451.1 ± 45.9 vs. 372.1 ± 52.1 cm/s; P < 0.001) and mean AVPGs (49.2 ± 14.5 vs. 30.3 ± 11.6 mmHg; P = 0.002) than those without. The optimal binary cut-off aortic valve peak velocity values and the mean AVPG associated with the presence of SFR before TAVI were >410.0 cm/s (specificity, 75.0%; sensitivity, 92.3%) and >37.4 mmHg (specificity, 83.3%; sensitivity, 92.3%), respectively. After TAVI, SFR immediately disappeared in 11 of 13 patients with SFR (84.6%). Overall, the systolic coronary VTI significantly increased after TAVI (2.0 ± 4.7 vs. 6.4 ± 3.2 cm, P < 0.001), and this increase was greater in patients with SFR than in those without SFR before TAVI (interaction P = 0.035).

SFR was found to be associated with the severity of AS and with a greater increase in systolic coronary flow immediately after TAVI.