Abstract
Introduction
Aortic stenosis (AS) patients are heterogeneous. The relationship between stenosis severity, transvalvular flow state and gradients is conflictive and non-linear.
Objective
To evaluate the relationship between transvalvular flow state and gradients with the anatomopathological aortic valve characteristics and perioperative morbimortality among patients (pt) submitted to aortic valve replacement (AVR).
Methods
We analyzed 516 pt with symptomatic severe AS (effective valve area <1 cm2) with preserved left ventricular ejection fraction (>50%) submitted to AVR. Perioperative mortality and a combined endpoint (death, low cardiac output syndrome and acute renal injury) were analyzed dividing the population by transvalvular flow (35 ml/m2) and mean gradient (40 mmHg), both measured by echocardiography. A morphologic evaluation of 383 operatively excised native cardiac valves was performed. Valvular thickening and calcification were categorized in mild, moderate and severe.
Results
Male subjects represented 52.9% (283 pt). Mean age were 69±11.5 years. Pt showed a mean ejection fraction of 61±4.8%, the peak gradient was 86.2±24 mmHg, and mean gradient was 53±18 mmHg.
Cardiac low output syndrome (normal flow (NF) – 14%, low flow (LF) – 23%; p<0,02), IABP (NF 1,8%, LF 6%, p<0,02) and perioperative mortality (NF 2,7%, LF 7%, p<0,02) were more frequent in low flow pt (185 – 35%).
Bicuspid valves represented 24.5% of the whole population. Bicuspid patients were younger 64±9 vs 73±12 years (p<0.05) and had more moderate–severe calcification (MSC) 93.4% vs 75.6% (p<0.05).
No difference was found in moderate -severe thickening (MSTh) and MSC when analyzing the population by flow (35 ml/m2). On the contrary, low gradient pt (<40mmHg) had lower MSC and MSTh. (Table)
Finally, 4 groups were considered: normal flow–high gradient NFHG (52.2%), normal flow–low gradient NFLG (12%), low flow–high gradient LFHG (25.5%) and low flow–low gradient LFLG (10.1%). A trend toward more perioperative events was seen in the LF-LG group despite less calcified and thickened valves. (Figure)
Table 1 Normal Flow Low Flow P value Normal gradient Low gradient P value M-S thickening 143 (58.1%) 80 (58.3%) NS 186 (62.4%) 37 (43.5%) 0.0018 M-S calcification 195 (79.2%) 119 (86.8%) NS 263 (88.2%) 51 (60%) <0.05 Bicuspid valve 62 (25%) 32 (23%) NS 62 (25.2%) 32 (23.3%) NS M-S: Moderate-Severe.
Figure 1
Conclusions
In our population of severe symptomatic AS with preserved ejection fraction submitted to AVR, low gradient pts had less calcified and thickened valves. LFLG pts presented a trend towards more perioperative events despite having less valvular calcification.
DeepFlow: Detecting Optimal User Experience From Physiological Data Using Deep Neural Networks
