Value of transthoracic echocardiography combined with cardiac troponin I in risk stratification in acute pulmonary thromboembolism

Abstract

Acute pulmonary thromboembolism (APE) causes right ventricular dysfunction (RVD) and cardiac troponin I (cTnI) elevation. Patients with RVD and cTnI elevation have a worse prognosis. Thus, early detection of RVD and cTnI elevation is beneficial for risk stratification. In this study, we assessed 14-day adverse clinical events and combined RVD on transthoracic echocardiography (TTE) with cTnI in risk stratification among a broad spectrum of APE patients. The prospective multi-centre trial included 90 patients with confirmed APE from 12 collaborating hospitals. Acute RVD on TTE was diagnosed in the presence of at least 2 of the following: right ventricular dilatation (without hypertrophy), loss of inspiratory collapse of inferior vena cava (IVC), right ventricular (RV) hypokinesis, tricuspid regurgitant jet velocity > 2.8 m/s. The study patients were divided into two groups according to clinical and echocardiographic findings at presentation: Group I: 50 patients with RVD; Group II: 40 patients without RVD. More than half of the patients (50/90, 55.6%) had RVD. Nearly one third (26/90, 28.9%) of patients had elevated cTnI at presentation and only 4.2% on the fourth day after initial therapy. A multiple Logistic regression model implied RVD, right and left ventricular end-diastolic diameter ratio (RVED/LVED), and cTnI independently predict an adverse 14-day clinical outcome (P < 0.01). Receiver operating characteristics (ROC) curves revealed that the cut-off values of RVED/LVED and cTnI yielding the highest discriminating power were 0.65 and 0.11 ng/ml, respectively. Furthermore, the incidence of an adverse 14-day clinical event in patients with RVD and elevated cTnI was greater (40.7%) than in patients with elevated cTnI or positive RVD alone (0% and 8.3%, respectively) (P < 0.001). RVD, RVED/LVED, and cTnI are independent predictors of 14-day clinical outcomes. The patients with RVED/LVED greater than 0.65 and cTnI higher than 0.11 ng/ml at presentation possibly have adverse 14-day events. RVD combined with cTnI can identify a subgroup of APE patients with a much more guarded prognosis.