Predicting heart failure during hospitalization in myocarditis

Type of funding sources: None.

Currently, there is little evidence available regarding their predictive potential of Monocyte-to-lymphocyte ratio (MLR) in patients diagnosed with myocarditis.

We aimed to investigate if MLR can predict heart failure during hospitalization in patients with clinical suspicious of acute myocarditis.

Retrospective study with patients admitted with the clinical suspicion of myocarditis in our center from February/2016 to September/2021. A total of 74 patients were included and divided into two groups based on MLR. ROC-analysis was conducted and AUC was calculated for the prediction of heart failure during hospitalization (0.82). Optimal cut-off for MLR was calculated by means of the Youden Index (MLR ≥ 0,817 (sens.: 73%, spec.: 80%). The primary outcome was heart failure during hospitalization.

We included 74 patients (90,5% males; mean age 37,1±15,1 years old), 96,8% presenting with chest pain and 68,9% presenting with ST-segment elevation on electrocardiogram. During hospitalization, 4 patients needed ionotropic support, 7 had supraventricular tachycardia, 14 non-sustained ventricular tachycardia, 2 sustained ventricular tachycardia, 1 needed extracorporeal membrane oxygenation and 11 had heart failure.

Both groups had similar age (39,0±16,9 vs 36,5±16,7 years, p=0,59), previous history of myocarditis (8,9% vs 5,6%, p=0,65), smoking history (16,7% vs 33,9%, p=0,34), diabetes mellitus (7,1% vs 2,6%, p=0,24), dyslipidemia (33,3% vs 19,6%,p=0,23), arterial hypertension (11,1% vs 14,3%,p=0,73), ST-segment elevation on admission (72,7% vs 63,8%, p=0,45), pro-BNP levels on admission [522 (IQR 222-1253) mg/dl vs 495 (IQR 222-970) mg/dl, p = 0,46].

Patients with MLR ≥ 0,817 (24,3%) had lower Left ventricular ejection fraction on admission (45,9%±14,1% vs 53,3%±8,4, p=0,008), high Peak C-reactive protein [13 (IQR 4,5-22) vs 4,5 (IQR 4-6,1), p=0,001] and peak troponin levels [1,98 (IQR 0,98-2,81) vs 0,87 (IQR 0,55-1,74), p=0,007] were higher in this group.

Throughout a median hospital stay of 4 days (IQR 3,5–7), 11 patients (17,7%) experienced the primary outcome.

After adjusting for possible cofounders, MLR ≥ 0,817 was an independent predictor of heart failure during hospitalization (HR 6,83, 95% CI 1,55-30,01, p=0,011).

MLR in our population, was a predictive factor for heart failure during hospitalization in patients with acute myocarditis. MLR could facilitate an early risk stratification and clinical management in these patients.