Left Ventricular Systolic Function and Inpatient Mortality in Patients Hospitalized with Coronavirus Disease 2019 (COVID-19)

To the Editor:

Although prior studies have reported findings related to left ventricular function on transthoracic echocardiography (TTE) in patients with coronavirus disease 2019 (COVID-19),1, 2, 3, 4, 5 the association of left ventricular ejection fraction (LVEF) with inpatient mortality in this population has not been well described.

To explore this further, we collected data on clinical variables and mortality for all patients hospitalized with COVID-19 who underwent an inpatient TTE between March 19, 2020, and April 30, 2020. Variables included age, sex, race, 17 preexisting medical conditions, intensive care unit stay, mechanical ventilation, intravenous pressor support, peak serum biomarkers (troponin T, pro-B-type natriuretic peptide [proBNP], d-dimer, C-reactive protein, interleukin-6, ferritin, and procalcitonin), and LVEF reported on initial inpatient TTE. Inpatient all-cause death and adjudicated cardiovascular death were assessed through June 1, 2020. To evaluate the association of LVEF with mortality relative to other variables, we performed an exploratory analysis of predictors of mortality. Variables significantly different in univariate analyses for patients who died compared with those who survived using a P value <.05 were placed into a stepwise logistic regression model, with a P value <.05 required to remain in the model. We also compared absolute mortality rates for patients with LVEF of ≥50%, 40% to 49%, 30% to 39%, and <30%.

A total of 75 patients hospitalized with COVID-19 underwent a TTE at a median of 8 days from admission, and 33 (44%) had a documented TTE before admission. The median age was 60 years (interquartile range, 47–66 years), 20 (27%) were women, and 17 (23%) had LVEF < 50%. Compared with patients with LVEF ≥ 50%, those with LVEF < 50% had higher troponin T (P=.031) and proBNP (P = .008) levels, with no differences in any baseline characteristics aside from prior history of reduced LVEF (P=.049), which was observed in 2 patients with LVEF<50%. Among patients with LVEF < 50%, 11 of 17 (65%) died compared with 15 of 58 (26%) with LVEF≥50%(P=.007).Among eight of 31 candidate variables initially included in the stepwise model, mechanical ventilation (odds ratio, 22.6; 95% CI, 3.0–170.4), LVEF < 50% (odds ratio, 8.2; 95% CI, 1.4–46.9), and proBNP above the cohort median value (odds ratio, 5.8; 95% CI, 1.4–23.9) remained in the final model as the strongest predictors of mortality, with a C statistic of 0.86. Mortality rates were progressively higher with more severe left ventricular dysfunction (P = .013; Figure 1 ). Only two deaths were attributed to cardiovascular causes, both in patients with LVEF between 20% and 29% and no prior history of heart failure.

Figure 1.

Inpatient mortality based on LVEF for patients hospitalized with COVID-19. ^∗P value assessing difference in mortality across LVEF categories using the Fisher exact test. LVEF, Left ventricular ejection fraction determined by inpatient transthoracic echocardiogram.

This study suggests that LVEF is strongly associated with inpatient mortality in patients hospitalized with COVID-19, even though deaths were primarily from noncardiovascular causes. Broader assessment of LVEF in patients with COVID-19 could help estimate the risk of death and guide acute medical management in this population. However, the cohort size limited our ability to determine associations with high precision. In addition, we only studied patients at a single center who underwent an inpatient TTE, and findings may vary in other populations. Larger studies incorporating LVEF based on TTE and point-of-care ultrasound are needed to more definitively determine the prognostic significance of LVEF in patients with COVID-19.