Left ventricular myocardial work efficiency as an independent correlate of the presence of heart failure in patients with severe aortic stenosis and preserved left ventricular ejection fraction

Introduction: Symptoms’ occurrence plays a key role in the management of patients (pts) with severe aor-tic stenosis (AS) and preserved left ventricular ejection fraction (LVEF). However, the presence of heart failure (HF) symptoms, reflecting the exhaustion of LV com-pensatory mechanisms, may be difficult to assess in el-derly pts with AS. New echocardiographic indices of LV function are able to detect the subtle alterations in myocardial mechanics and emerge as promising tools for improving risk stratification in these patients. Objective: To assess the differences in LV mechanical dispersion and myocardial work efficiency between symptomatic and asymptomatic pts with severe AS and preserved LVEF, and the relationship between the im-pairment of these parameters and the presence of HF symptoms.
Methods: We prospectively included 75 patients with severe AS (aortic valve area, AVA <1 cm2) and LVEF >50%, in sinus rhythm, with no more than mild aor-tic or mitral regurgitation. Patients were divided into two groups based on the presence of HF: symptomatic (49 pts) and asymptomatic (26 pts). A negative exer-cise echocardiography was required to confirm the asymptomatic status. Segmental LV strain analysis was assessed by speckle tracking echocardiography and the dispersion of regional LV strain curves was computed automatically. LV myocardial work was evaluated using a non-invasive method to quantify segmental work using segmental strain and a standardized LV pressu-re curve adjusted to brachial cuff pressure and valvular events. LV myocardial work efficiency (constructive work divided by the sum of constructive and wasted work), a parameter which is not affected by peak LV pressure, was derived.
Results: No significant differences were found betwe-en symptomatic and asymptomatic patients regarding age (66±11 vs. 64±16 yrs, p=0.5), gender, cardiovascu-lar risk factors and comorbidities (p>0.1 for all) and the severity of AS (AVA, 0.73±0.17 vs. 0.78±0.17 cm2, p=0.1 and mean gradient 59±18 vs. 55±23 mmHg, p=0.5). Indexed LV mass and LVEF were not signifi-cantly different between symptomatic and asymptoma-tic pts (142±35 vs. 137±29 g/m2, p=0.5 and 63.5±6.9 vs. 63.8±5.1%, p=0.8) while global LV longitudinal strain was more impaired in symptomatic pts (-15.1±3.6 vs. -16.8±2.6% p=0.03). LV mechanical dispersion was 55±16 ms in asymptomatic pts and significantly higher in symptomatic pts: 66±18 ms (p=0.01). LV myocardial work efficiency was significantly lower in symptoma-tic compared to asymptomatic pts: 91±4 vs. 94±3%, p=0.002. In multivariate analysis this parameter emer-ged as an independent correlate of the presence of HF symptoms (p=0.004).
Conclusions: In symptomatic patients with severe AS and preserved LVEF we found an increased LV mecha-nical dispersion and impaired LV work efficiency com-pared to asymptomatic pts with the same degree of AS severity, LV hypertrophy and similar LVEF. LV myocardial work efficiency was an independent correlate of the presence of HF symptoms in our study group.

ISSN – online: 2734 – 6382
ISSN-L 1220-658X
ISSN – print: 1220-658X
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CODE: 379
CME Credits: 10 (Romanian College of Physicians)