Prevalence and prognostic significance of cardiac abnormalities in the ICU: an echocardiographic study

Introduction

The aim was to describe the prevalence and type of cardiac abnormalities in ICU patients detected using echocardiography and to assess whether those abnormalities are correlated with ICU survival.

Methods

Prospective cohort study. Consecutive patients hospitalized in the UCSC medical-surgical ICU for >24 hours were evaluated using transthoracic echocardiography (TTE). Patients admitted for postoperative monitoring or in an agonal state were excluded. Transesophageal echocardiography (TEE) was used when TTE was technically impossible. Measured parameters included: volume, thickness, global and regional kinesis of the left ventricle (LV), systolic function of the right ventricle (RV), and valvular function.

Results

From 1 March to 30 June 2009 a total of 100 patients (median age 68.5 years (IQR 50 to 77.5)) were included in the study. Medium SAPS II was 46 ± 15. ICU mortality rate was 29%. Median LOS in ICU was 14 days. TTE was technically feasible in 97 patients; the other three patients underwent TEE. Significant cardiac abnormalities were found in 66 patients, 41 of whom had no history of cardiac disease. The most frequent abnormalities were: tricuspidal regurgitation (45.3%), regional asynergies of LV (32%), left heart failure (30.2%) and mitral regurgitation (28%). The median left ventricular ejection fraction (EF) in our population was 50% (IQR 15 to 72%). Left ventricular end-diastolic volume was 100 ml (IQR 78 to 130 ml). Mean tricuspid annular systolic excursion (TAPSE) was lower in patients who died (18.9 vs 20.8 mm; P = 0.09). TAPSE was significantly correlated to EF (r coefficient = 0.48; P < 0.0001). Pulmonary artery systolic pressure was significantly higher in patients who died than in those who survived to the ICU (49.8 ± 13.0 mmHg vs 35.0 ± 12.8 mmHg; P = 0.045). On logistic regression, prediction of ICU mortality was better (AUC = 0.901 vs 0.787) when cardiac abnormalities detected by echocardiography were added to a model based on age and SAPS II.

Conclusions

In our study, a complete echocardiographic assessment was possible using TTE in 97% of patients. Two-thirds of our population had echocardiographic abnormalities, 62.1% of whom were previously unknown. The presence of LV asynergies and reduced RV systolic function were associated with a worse prognosis. Detection of cardiac abnormalities increased prediction of ICU mortality based on logistic regression.