Abstract
PurposeRecently, a “U” hazard ratio curve between resting left ventricular ejection fraction (LVEF) and prognosis has been observed in patients referred for routine clinical echocardiograms. The present study sought to explore whether a similar “U” curve existed between resting LVEF and coronary flow reserve (CFR) in patients without severe cardiovascular disease (CVD) and whether impaired CFR played a role in the adverse outcome of patients with supra-normal LVEF (snLVEF, LVEF ≥ 65%).MethodsTwo hundred ten consecutive patients (mean age 52.3 ± 9.3 years, 104 women) without severe CVD underwent clinically indicated rest/dipyridamole stress electrocardiography (ECG)-gated 13 N-ammonia positron emission tomography/computed tomography (PET/CT). Major adverse cardiac events (MACE) were followed up for 27.3 ± 9.5 months, including heart failure, late revascularization, re-hospitalization, and re-coronary angiography for any cardiac reason. Clinical characteristics, corrected CFR (cCFR), and MACE were compared among the three groups categorized by resting LVEF detected by PET/CT. Dose–response analyses using restricted cubic spline (RCS) functions, multivariate logistic regression, and Kaplan–Meier survival analysis were conducted to evaluate the relationship between resting LVEF and CFR/outcome.ResultsAn inverted “U” curve existed between resting LVEF and cCFR (p = 0.06). Both patients with snLVEF (n = 38) and with reduced LVEF (rLVEF, LVEF < 55%) (n = 66) displayed a higher incidence of reduced cCFR than those with normal LVEF (nLVEF, 55% ≤ LVEF < 65%) (n = 106) (57.9% vs 54.5% vs 34.3%, p < 0.01, respectively). Both snLVEF (p < 0.01) and rLVEF (p < 0.05) remained independent predictors for reduced cCFR after multivariable adjustment. Patients with snLVEF encountered more MACE than those with nLVEF (10.5% vs 0.9%, log-rank p = 0.01).ConclusionsPatients with snLVEF are prone to impaired cCFR, which may be related to the adverse prognosis. Further investigations are warranted to explore its underlying pathological mechanism and clinical significance.
Highlights
A “U” hazard ratio curve between resting left ventricular (LV) ejection fraction and prognosis has been observed in patients referred for routine clinical echocardiograms; abnormal LV ejection fraction (LVEF), reduced and supra-normal LVEF, was correlated with adverse prognosis regardless of age, sex, or other relevant comorbidities including heart failure (HF) [1]. snLVEF is proposed as a new concept because of its newly observed long- or short-term worse outcome in patients with acute or chronic coronary syndrome with or without HF and even in those without cardiac symptoms, such as old women, hypertension, tumor, sepsis, and serious anemia [1,2,3,4,5]
Women with snLVEF were reported a propensity towards reduced coronary flow reserve (CFR), indicating a potential mechanism of coronary microvascular dysfunction (CMD) [5]
We explored the relationship between resting LVEF detected by positron emission tomography/ computed tomography (PET/CT) and CFR as well as the role of CMD in the adverse outcome of patients with snLVEF; LVEF at stress was not considered due to its limited accessibility in clinical practice
Summary
MethodsRecently, a “U” hazard ratio curve between resting left ventricular (LV) ejection fraction and prognosis has been observed in patients referred for routine clinical echocardiograms; abnormal LV ejection fraction (LVEF), reduced and supra-normal LVEF (snLVEF), was correlated with adverse prognosis regardless of age, sex, or other relevant comorbidities including heart failure (HF) [1]. snLVEF is proposed as a new concept because of its newly observed long- or short-term worse outcome in patients with acute or chronic coronary syndrome with or without HF and even in those without cardiac symptoms, such as old women, hypertension, tumor, sepsis, and serious anemia [1,2,3,4,5]. A “U” hazard ratio curve between resting left ventricular (LV) ejection fraction and prognosis has been observed in patients referred for routine clinical echocardiograms; abnormal LV ejection fraction (LVEF), reduced and supra-normal LVEF (snLVEF), was correlated with adverse prognosis regardless of age, sex, or other relevant comorbidities including heart failure (HF) [1]. Reduced CFR is involved in a variety of diseases [14], its overall trend along with changing LVEF has not been depicted Obtaining such information may help to identify higher risk patients at an early stage; under the disappointing results of clinical trials of HF with preserved LVEF (HFpEF) to date [15], it may help to clarify the phenotype and improve the tailored management
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