Pulmonary embolism is associated with varying degrees of pulmonary vascular obstruction. This study was undertaken to establish whether the extent of perfusion defect in lung scintigraphy can be predicted from analysis of echocardiographic measurements in patients with pulmonary embolism.

We retrospectively studied 28 patients who presented with clinical evidence of pulmonary embolism. In order to compare the extent of perfusion defect in lung scintigraphy, we devised a scoring system (echocardiographic severity index, ESI) for various echocardiographic parameters, which include right ventricle size, area, shape, systolic function, and pulmonary artery pressure. [ESI=sum of scores/number of parameters measured].

The mean values (±SD) of each parameter were as follow; right ventricular end-diastolic dimension (RVedD), 34.5±5.7 mm; LVedD, 40.9±5.2 mm; ratio of RVedD to LVedD, 0.87±0.2; right ventricular end-diastolic area (RVedA), 24.7±9.5 cm2; right ventricular end-systolic area (RVesA), 17.8±7.8 cm2; fractional area change, 28.8±9.7%; angle between IVS and RV, 96.0±14.8°; RV hypokinesia, absence or mild in 29%, moderate in 50%, severe in 21%; TR grade, absence or mild in 25%, moderate in 43%, severe in 32%; pulmonary artery systolic pressure, <30 mmHg in 21%, 30 to 50 mmHg in 68%, >50 mmHg 11% of patients. The echocardiographic severity index (ESI) in patients with pulmonary embolism was 0.52±0.24, and the perfusion defect score was 0.21±0.14. There was a close correlation between the ESI and the extent of perfusion defect (r=0.622, p<0.01).

The echocardiographic severity index may reflect the extent of the perfusion defects in patients with pulmonary embolism, therefore it is potentially applicable in clinical practice for evaluating patients with pulmonary embolism and furthermore in their follow-up over a period of time.