Aortic Valve Gradient and Mortality in Patients Undergoing Transcatheter Aortic Valve Implantation for Severe Aortic Stenosis

Background: Mortality of patients undergoing transcatheter aortic valve implantation (TAVI) remains high, making optimal patient selection for this costly procedure extremely important. We aimed to evaluate the relationship between baseline aortic valve gradients (AVGs) and mortality post TAVI and assess the role of AVG in risk stratification for TAVI candidates.

Methods: We analyzed data on 1,186 consecutive patients with severe Aortic Stenosis (AS) that underwent TAVI at 3 tertiary centers from 2008 through 2014. The relation between AVG and mortality was evaluated among all patients and in subgroup of patients with high AVGs using the Cox proportional hazard model adjusting for multiple prognostic variables. Peak AVG was categorized as: < 60mmHg, 60-100mmHg, >100mmHg, and assessed as a continuous measure.

Results: Patients had a peak AVG of (mean+SD) 75+24 mmHg, mean AVG of 47 +17 mmHg, and aortic valve area of 0.7+0.2 cm². During a mean follow up of 1.8 years, baseline AVG was inversely associated with mortality. By multivariable analysis, patients with AVG 60-100 mmHg and >100 mmHg had a respective 30% (p=0.02) and 70% (p<0.001) reduction in mortality compared to patients with AVG<=60%. Every 10 mmHg increase in peak AVG was associated with 9% reduction in mortality (HR 0.914, p=0.003). Subgroup analyses among patients with left ventricular ejection fraction (LVEF) >40%, or peak AVG>=60 mmHg yielded similar results (HR 0.910, p=0.003 and HR 0.905, p=0.025, per10 mmHg increase in peak AVG respectively ). Analyses using mean AVGs yielded consistent results to those of peak AVG.

Conclusions: Baseline AVGs are directly associated with improved survival post TAVI. These results were consistent also in patients with high gradient AS, suggesting that AVG can be used to select patients most likely to benefit from TAVI.