Relationship Between the Ratio of Acceleration Time/Ejection Time and Mortality in Patients With High‐Gradient Severe Aortic Stenosis

Abstract

Background The ratio of acceleration time/ejection time (AT/ET) is a simple and reproducible echocardiographic parameter that integrates aortic stenosis severity and its consequences on the left ventricle. No study has specifically assessed the prognostic impact of AT/ET on outcome in patients with high‐gradient severe aortic stenosis (SAS) and no or mild symptoms. We sought to evaluate the relationship between AT/ET and mortality and determine the best predictive AT/ET cutoff value in these patients. Methods and Results A total of 353 patients (median age, 79 years; 46% women) with high‐gradient (mean pressure gradient ≥40 mm Hg and/or aortic peak jet velocity ≥4 m/s) SAS, left ventricular ejection fraction ≥50%, and no or mild symptoms were studied. The impact of AT/ET ≤0.35 or >0.35 on all‐cause mortality was retrospectively studied. During a median follow‐up of 39 (25th–75th percentile, 23–62) months, 70 patients died. AT/ET >0.35 was associated with a considerable increased mortality risk after adjustment for established prognostic factors in SAS under medical and/or surgical management (adjusted hazard ratio [HR], 2.54; 95% CI, 1.47–4.37; P <0.001) or conservative management (adjusted HR, 3.29; 95% CI, 1.70–6.39; P <0.001). Moreover, AT/ET >0.35 improved the predictive performance of models including established risk factors in SAS with better global model fit, reclassification, and discrimination. After propensity matching, increased mortality risk persisted when AT/ET >0.35 (adjusted HR, 2.10; 95% CI, 1.12–3.90; P <0.001). Conclusions AT/ET >0.35 is a strong predictor of outcome in patients with SAS and no or only mild symptoms and identifies a subgroup of patients at higher risk of death who may derive benefit from earlier aortic valve replacement.

Value of Left Ventricular Indexed Ejection Time to Characterize the Severity of Aortic Stenosis

“…The opposite was observed in the prevalence of SF without LF, a condition which was more frequent in patients with SAS compared to those without. This was also observed in other AS study cohorts [ 11 , 18 ] ( Figure 7 ). Both the lower frequency of LF without SF and the higher frequency of SF without LF in SAS patients are related to higher LVET values and support the independent role of AS in prolonging LVET.…”

“…We assessed LV forward flow using SVI, with a 35 mL/m 2 cutoff value for LF [ 1 , 2 ], and FR, with a 210 mL/s cutoff value for SF [ 11 ]. In recent years, SF has been reported to identify the flow reduction that may induce pseudosevere AS [ 18 ].…”

“…In discordant cases in which an AVA < 1 cm 2 and MG < 40 mmHg or V max < 4 m/s were found along with a low flow (LF) status, pseudosevere AS was differentiated from true LF low-gradient (LG) SAS by dobutamine stress echocardiography, cardiac catheterization (to obtain AVA) or a semi-quantitative assessment of calcium score (eCS) ≥3 [ 10 ], and re-classified as MAS. The ratio of continuous wave Doppler acceleration time/ejection time (AT/ET) as an additional marker of SAS was also calculated [ 11 ].…”

The Impact of Left Ventricular Performance and Afterload on the Evaluation of Aortic Valve Stenosis: A 1D Mathematical Modeling Approach

“…While the rapid opening of the aortic valve is a valid assumption in healthy individuals, this is not the case in those suffering from stenosis due to the prolonged opening time [ 21 ]. Studies have shown that the ratio of acceleration time—the required time to reach a maximum aortic flow—to the total ejection time increases as the severity of aortic stenosis increases [ 21 , 22 , 23 ]. Virag et al [ 24 ] used the lumped parameter model of the left ventricle and arterial system coupling, and the motion of the aortic valve area was defined as a function of volume displaced by leaflets during the opening and closure phases in systole.…”