0300: Course of vascular obstruction after pulmonary embolism as assessed by ventilation-perfusion lung scan follow-up

Abstract

We investigated the course of residual pulmonary vascular obstruction (RPVO) from discharge up to 3 – 6 months after pulmonary embolism (PE). Prospective registry including 202 consecutive patients with PE who survived the acute phase (high risk PE: 12.4%, intermediate-risk: 65.8%, and low- risk: 21.8%). Patients with a prior history of chronic pulmonary disease were excluded. Ventilation-perfusion (V/Q) lung scan was performed in all patients before discharge, and again at follow-up (between 3 and 6 months after discharge). Treatment was in accordance with current guidelines. Evolution of RPVO was determined as the relative change in lung perfusion (in %) between discharge and follow-up V/Q scans. Between both lung scans, RPVO decreased from 29.1±15% to 10.9±11.4%, with an average relative change of 61.7±33.4%. Overall, 49 patients (24.2%) presented a full resolution of lung perfusion. Relative change in RPVO was <50% in57 (28%), including 18 (8.9%) patients who showed no modification on lung scan. The relative change in RPVO was constant, regardless of the level of RPVO at discharge (p=0.07). Patients who presented full resolution on the second lung scan (n=49) had significantly lower RPVO at discharge as compared to those without full resolution (21.7±10.1% vs. 31.4±16.0% respectively, p<0.001), and almost 75% of those with full resolution had RPVO<30% at discharge. Multivariate logistic regression showed that high-risk PE and right ventricle (RV) to left ventricle (LV) ratio (by quartiles) at discharge were independently related to unfavorable course of RPVO during follow-up (high-risk PE: OR 3.6, 95% CI 1.54-8.43, p<0.001; RV/LV ratio: OR 3.42, 95% CI 1.12-9.45, p=0.03). Our findings suggest that systematic lung scan follow-up should not be considered after PE, except in patients with high-risk PE or those with echocardiographic signs of RV pressure overload at discharge.