Background: Patients with severe aortic stenosis (AS) and low valve gradient have poor outcome after trans-catheter aortic valve implantation (TAVI) as compared with patients with high aortic valve gradients. However, data on the relation between aortic valve gradient (AVG) as a continuous variable and clinical outcome after TAVI are limited.
Methods: We analyzed data on 319 consecutive patients with severe AS that underwent TAVI at our institution. We investigated the relation between AVG as a continuous variable and outcome among all patients and in subgroups of patients without low-gradient severe AS, using the Cox proportional hazard model adjusting for multiple prognostic variables.
Results: Patients had a peak AVG of (mean+SD)80+23 mmHg, mean AVG of 50.2 +15.9 mmHg, aortic valve area of 0.64+0.16 cm2 and left ventricular ejection fraction (LEVF) of 54.49+8.36%. During a mean follow up of 1.9 years, baseline AVG was inversely associated with mortality and with cardiac hospitalization or death after TAVI. Every 10 mmHg increase in baseline mean AVG was associated with 20% reduction in mortality (Hazard ratio [HR] 0.80, 95% confidence interval [CI] 0.67-0.97, p=0.021), and 22% reduction in cardiac hospitalization or death (HR 0.78, 95%CI 0.67 - 0.92, p=0.003). Consistently, every 10 mmHg increase in peak AVG was associated with 15% (p=0.014) and 17% (p=0.002) reduction in mortality and cardiac hospitalization or death, respectively. Subgroup analysis of patients with LVEF>40%, mean AVG>35 mmHg, or peak AVG>60 mmHg yielded similar results. Aortic valve area as a continuous variable was not correlated with clinical outcome.
Conclusions: Both mean and peak baseline AVGs are directly associated with improved survival post TAVI, independent of LVEF or the presence of low-gradient AS, suggesting that AVG can be used to select patients most likely to benefit from TAVI.
