Analysis of the 60/60 Sign and Other Right Ventricular Parameters by 2D Transthoracic Echocardiography as Adjuncts to Diagnosis of Acute Pulmonary Embolism

Introduction The 60/60 sign in 2D transthoracic echocardiography (TTE) - a combination of pulmonary acceleration time (PAT) less than 60 milliseconds and tricuspid regurgitation (TR) jet gradient of less than 60 mmHg - has been found to be specific for the diagnosis of pulmonary embolism (PE). Materials and methods An observational prospective analysis was carried out on cases of suspected PE presenting to the emergency room (ER). TTE was performed on all cases with suspected PE prior to computed tomography pulmonary angiography (CTPA). Emphasis was placed on measurement of PAT and early systolic notching (ESN) on the pulsed wave (PW) Doppler of the pulmonary valve, TR jet gradient, right ventricle systolic excursion velocity (RV S’) by tissue doppler imaging (TDI), tricuspid annular plane systolic excursion (TAPSE), and right ventricle to left ventricle end-diastolic dimension ratio (RV:LV EDD) in modified parasternal short-axis view. These signs were taken as screening tests and compared to CTPA as the standard test. Patients were followed up until hospital discharge or death. Observations Fifty-six cases of suspected PE were enrolled for the study. Of these, 24 cases of PE were confirmed by CTPA. Out of 24 cases of PE, 15 were high-risk PE, six were intermediate high-risk PE, and three were intermediate low-risk PE. The mean age was 53.07±9.79 years with a male-to-female ratio of 1.95:1. The 60/60 sign was present in 70.83% of cases of PE. RV:LV EDD in a modified short-axis view of more than 0.9 was present in 91.67% of cases of PE, and ESN on the PW Doppler of the pulmonary valve was present in 75% of cases of PE. The 60/60 sign, RV:LV EDD ratio more than 0.9, and ESN showed sensitivities of 70.83%, 91.67%, 75%, and specificities of 93.75%, 75%, and 100%, respectively for PE. For prediction of mortality, presence of the 60/60 sign (Odds Ratio=8.13, p-value=0.034) and ESN (Odds Ratio=17.50, p-value=0.02) were statistically significant. Conclusions 60/60 sign and ESN are specific for the diagnosis of PE but have poor sensitivity.