RESUMEN
BACKGROUND: A subset of patients with severe aortic stenosis (AS) have lower stroke volumes and valve gradients despite a normal left ventricular ejection fraction (LVEF), referred to as paradoxical low-flow AS (PLF AS). However, the role of right ventricular (RV) function in patients with severe AS and preserved LVEF is not known. We hypothesized that right ventricular function is associated with left ventricular stroke volume in patients with severe AS and preserved LVEF. METHODS: From an echocardiographic database, we retrospectively identified 102 patients with an indexed aortic valve area ≤0.6 cm(2) /m(2) and LVEF ≥ 50%. We used univariate and multivariate linear regression analysis to assess the association between aortic valve stroke volume index (SVi) and right ventricular systolic function as measured by tricuspid annular plane systolic excursion (TAPSE) and by right ventricular fractional area change (FAC). RESULTS: Our population was 98% male with mean age 77.4 ± 9.3 years and mean SVi of 36.1 ± 7.9 mL/m(2) . Forty-four patients (43%) met criteria for PLF AS. TAPSE and FAC were positively associated with SVi in both univariate and multivariate regression analysis after correcting for left ventricular variables (ß coefficient - TAPSE (cm): 4.59 ± 1.3, P = 0.001; FAC (%): 0.19 ± 0.08, P = 0.014). Additionally, PLF AS patients had significantly lower mean TAPSE and lower mean FAC when compared dichotomously to normal flow AS patients (P < 0.05). CONCLUSIONS: Right ventricular systolic function assessed by TAPSE and FAC is significantly related to aortic valve flow in patients with severe AS and preserved LVEF.
Asunto(s)
Estenosis de la Válvula Aórtica/diagnóstico por imagen , Estenosis de la Válvula Aórtica/fisiopatología , Volumen Sistólico , Disfunción Ventricular Derecha/diagnóstico por imagen , Disfunción Ventricular Derecha/fisiopatología , Función Ventricular Izquierda , Anciano , Estenosis de la Válvula Aórtica/complicaciones , Ecocardiografía/métodos , Femenino , Humanos , Masculino , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Disfunción Ventricular Derecha/etiologíaRESUMEN
BACKGROUND: The benefit of myocardial perfusion imaging (MPI) over exercise ECG stress testing alone is unclear in individuals attaining a workload of ≥10 METS. The purpose of this prospective study is to determine mortality and nonfatal cardiac events in patients at either intermediate pretest risk for CAD or patients with known CAD, achieving ≥10 METS regardless of peak exercise heart rate. The authors previously reported a low prevalence of significant ischemia in this patient cohort. METHODS: Baseline characteristics, ECG stress test findings, and perfusion and function results from quantitative gated (99m)Tc-SPECT MPI were compared by achievement of a maximum age-predicted heart rate ≥85% in 509 consecutive patients who reached ≥10 METS. Events including all-cause and cardiac mortality, non-fatal myocardial infarction (MI), and late revascularization (>4 weeks after MPI) were prospectively collected. RESULTS: Of the 509 patients achieving ≥10 METS, follow-up for mortality was obtained in 463 (91%). Those lost to follow-up were older and had higher rates of tobacco use. The prevalences of CAD risk factors, prior known CAD, and MPI abnormalities were higher for the 68 patients failing to reach 85% of their target heart rate. The rate of ≥10% left-ventricular (LV) ischemia by MPI remained very low irrespective of attained heart rate (0.6% (3/463)). Six (1.2%) had an LVEF < 40%. Death occurred in 12 (2.6%) patients, one of which was classified as cardiac (0.1%/year). The other 11 deaths were related to cancer. Additionally, there were three nonfatal MIs (0.7 %) and one late revascularization (0.2%). Only one of these patients had any ischemia on MPI. No cardiac event patient had exercise ST depression or ≥5% LV ischemia. CONCLUSIONS: Thus, patients at intermediate risk for CAD or known CAD achieving ≥10 METS have a very low prevalence of ≥10% LV ischemia and very low rates of cardiac mortality, nonfatal MI, and late revascularization, irrespective of heart rate achieved. Cardiac events did not correlate with abnormalities on the index MPI study. These results suggest that patients who attain ≥10 METS during exercise stress have an excellent prognosis over an intermediate term of follow-up, regardless of peak exercise heart rate achieved. The added value of MPI to standard exercise ECG testing in this population is questionable.