Valve Weight and Severity of Valve Calcification are less in Paradoxical Low Gradient than in High Gradient Severe Aortic Stenosis

Abstract

Background: Paradoxical low gradient (PLG) severe aortic stenosis (SAS) is a recently described subset of SAS, whose exact clinical significance is a matter of intense debate. Some authors indeed consider this new entity as a more advanced form of SAS, whereas others believe it represents a relatively benign form of AS. To get further insight into the pathophysiology of PLG SAS, we compared the weight of the valves explanted at the time of surgery (AVR) and the degree of valve calcification, two surrogates markers of the true stenosis severity, among consecutive patients with PLG SAS and high-gradient (HG) SAS. Methods: We prospectively recruited 38 consecutive patients (20 men; mean age: 73 yrs) with isolated non-rheumatic SAS (indexed aortic valve area (AVAi) 0.90) and in-vivo (r2=0.71) Agatston scores. Interestingly, valves explanted from patients with PLG SAS were lighter (1.58±0.65 vs 2.65±1.24 g, p=0.001) and showed lower ex-vivo Agatston scores (363±282 vs 1211±840, p<0.001) than HG SAS valves. These differences remained significant after adjustment for gender (1.58±0.65 vs 2.36±0.88 g, p=0.011 for valves weight and 363±282 vs 1023±597, p=0.002 for ex-vivo Agatston score). Conclusion: The valves weight and degree of valve calcification reported in our study indicate that PLG SAS valves are less severely affected than HG SAS valves. These data thus reinforce the hypothesis that PLG SAS is a lesser advanced form of aortic stenosis than HG SAS