RESUMEN

About one-tenth to one-third of patients with severe aortic stenosis (AS) do not develop left ventricular hypertrophy (LVH). Intriguingly, the absence of LVH despite severe AS is associated with lower prevalence of heart failure (HF), which challenges the classical notion of LVH as a beneficial compensatory response. Notably, the few studies that have attempted to characterize AS subjects with inadequately low left ventricular (LV) mass relative to LV afterload (i-lowLVM) described better prognosis and enhanced LV performance in AS associated with i-lowLVM, but those reports were limited to severe AS. Our aim was to compare myocardial function between moderate and severe AS with i-lowLVM. We retrospectively analyzed in-hospital records of 225 clinically stable nondiabetic patients with isolated moderate or severe degenerative AS in sinus rhythm, free of coexistent diseases. Subjects with i-lowLVM were compared to those with appropriate or excessive LVM (a/e-LVM), defined on the basis of the ratio of a measured LVM to the LVM predicted from an individual hemodynamic load. Patients with i-lowLVM and a/e-LVM did not differ in aortic valve area, LV end-diastolic diameter (LVd, a measure of LV preload), and circumferential end-systolic LV wall stress (cESS), an estimate of LV afterload. Compared to a/e-LVM, patients with i-lowLVM had increased LV ejection fraction (EF) and especially higher LV midwall fractional shortening (a better index of LV myocardial function than EF in concentric LV geometry) (p < 0.001-0.01), in both moderate and severe AS. LVd and cESS were similar in the four subgroups of the study subjects, i.e., moderate AS with i-lowLVM, moderate AS with a/e-LVM, severe AS with i-lowLVM, and severe AS with a/e-LVM (p > 0.6). Among patients with i-lowLVM, LVM did not differ significantly between moderate and severe AS (p > 0.4), while in those with a/e-LVM, LVM was increased in severe versus moderate AS (p < 0.001). In conclusion, the association of the low-LVM phenotype with better myocardial contractility may already develop in moderate AS. Additionally, cESS appears to be a controlled variable, which is kept constant over AS progression irrespective of LVM category, but even when controlled (by increasing LVM), is not able to prevent deterioration of LV function. Whether improved myocardial performance contributes to favorable prognosis and the preventive effect against HF in AS without LVH, remains to be studied.

RESUMEN

BACKGROUND: Degenerative aortic stenosis (AS), a disease of the elderly, frequently coexists with concomitant diseases, including type 2 diabetes (T2DM) which amplifies the cardiovascular (CV) risk. T2DM affects left ventricular (LV) structure and function via hemodynamic and metabolic factors. In concentric LV geometry, typical for AS, indices of LV midwall mechanics are better estimates of LV function than ejection fraction (EF). Effects of T2DM coexisting with AS on circumferential LV midwall systolic function and large artery properties have not been reported so far. Our aim was to compare characteristics of AS patients with and without T2DM, with a focus on LV midwall systolic function and arterial compliance. METHODS: Medical records of 130 electively hospitalized patients with moderate or severe isolated degenerative AS were retrospectively analyzed. Exclusion criteria included clinical instability, atrial fibrillation, coronary artery disease and relevant non-cardiac diseases. From in-hospital echocardiography and blood pressure, we calculated LV midwall fractional shortening (mwFS), circumferential end-systolic LV wall stress (cESS) and valvulo-arterial impedance (Zva), estimates of LV afterload, as well as systemic arterial compliance. RESULTS: Patients with (n = 50) and without T2DM (n = 80) did not differ in age, AS severity, LV mass and LV diastolic diameter. T2DM patients exhibited elevated cESS (247 ± 105 vs. 209 ± 84 hPa, p = 0.025) and Zva (5.8 ± 2.2 vs. 5.1 ± 1.8 mmHg per mL/m2, p = 0.04), and lower stroke volume index (33 ± 10 vs. 38 ± 12 mL/m2, p = 0.01) and systemic arterial compliance (0.53 ± 0.16 vs. 0.62 ± 0.22 mL/m2 per mmHg, p = 0.01). mwFS (11.9 ± 3.9 vs. 14.1 ± 3.7%, p = 0.001), but not EF (51 ± 14 vs. 54 ± 13%, p = n.s.), was reduced in T2DM. mwFS and cESS were inversely interrelated in patients both with (r = - 0.59, p < 0.001) and without T2DM (r = - 0.53, p < 0.001) By multiple regression, higher cESS (p < 0.001) and T2DM (p = 0.02) were independent predictors of depressed mwFS. CONCLUSIONS: In AS, coexistent T2DM appears associated with reduced systemic arterial compliance and LV dysfunction at the midwall level, corresponding to slightly depressed myocardial contractility.

Asunto(s)

Estenosis de la Válvula Aórtica/complicaciones , Diabetes Mellitus Tipo 2/complicaciones , Enfermedades Vasculares/etiología , Rigidez Vascular , Disfunción Ventricular Izquierda/etiología , Función Ventricular Izquierda , Anciano , Anciano de 80 o más Años , Estenosis de la Válvula Aórtica/diagnóstico por imagen , Estenosis de la Válvula Aórtica/fisiopatología , Adaptabilidad , Estudios Transversales , Diabetes Mellitus Tipo 2/diagnóstico , Diabetes Mellitus Tipo 2/fisiopatología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Enfermedades Vasculares/diagnóstico por imagen , Enfermedades Vasculares/fisiopatología , Disfunción Ventricular Izquierda/diagnóstico por imagen , Disfunción Ventricular Izquierda/fisiopatología

RESUMEN

Left ventricular hypertrophy (LVH) is traditionally considered a physiological compensatory response to LV pressure overload, such as hypertension and aortic stenosis (AS), in an effort to maintain LV systolic function in the face of an increased afterload. According to the Laplace law, LV wall thickening lowers LV wall stress, which in turn would be helpful to preserve LV systolic performance. However, numerous studies have challenged the notion of LVH as a putative beneficial adaptive mechanism. In fact, the magnitude of LVH is associated with higher cardiovascular morbidity and mortality, especially when LVH is disproportionate to LV afterload. We have briefly reviewed: first, the importance of non-valvular factors, beyond AS severity, for total LV afterload and symptomatic status in AS patients; second, associations of excessive LVH with LV dysfunction and adverse outcome in AS; third, prognostic relevance of the presence or absence of pre-operative LVH in patients referred for aortic valve surgery; fourth, time course, determinants and prognostic implications of LVH regression and LV function recovery after surgical valve replacement and transcatheter aortic valve implantation (TAVI) with a focus on TAVI-specific effects; fifth, the potential of medical therapy to modulate LVH before and after surgical or interventional treatment for severe AS, a condition perceived as a relative contraindication to renin-angiotensin system blockade.