PROGNOSTIC FACTORS IN RESTORATION OF PULMONARY FLOW AFTER SUBMASSIVE PULMONARY-EMBOLISM - A MULTIPLE-REGRESSION ANALYSIS

Defects as evaluated by lung perfusion scans may persist even 6 months after pulmonary embolism (PE), when treatment is withdrawn, The aim o f this study was to evaluate the effect of several potential factors o n the resolution of lung perfusion defects, both during the first days and at 6 months, when patients were discharged. In a retrospective fo llow-up cohort study we included 102 patients with PE, diagnosed lung from a ventilation/perfusion (V'/Q') scan, following Prospective Inves tigation of Pulmonary Embolism Diagnosis (PIOPED) criteria, together w ith a phlebographic study of lower extremities or angiography. Lung pe rfusion scan was performed at diagnosis, and in two follow-up evaluati ons, at 7-10 days and at 6 months. Potential factors studied were: age ; sex; presence of underlying cardiac or pulmonary disease; venous ins ufficiency; alveolar-arterial pressure difference for oxygen; delay in diagnosis; abnormalities in electrocardiogram or chest radiograph; an d the size of defects as shown in lung perfusion scans. All factors we re studied with regards to the size of the defects at the two follow-u p evaluations, through a univariate statistical analysis and two multi ple stepwise regression analysis. Multivariate statistical analysis se lected four factors: size of defects at diagnosis; prior cardiopulmona ry disease; delay in diagnosis; and sex, as synergistic variables to p redict defect size at 7-10 days, On the other hand, the defect size at 7-10 days was the only variable selected as a predictor of the size o f defects at 6 months. Resolution of pulmonary defects during the firs t days after diagnosis of pulmonary embolism is influenced by the init ial defect size, prior cardiopulmonary diseases and sex, The size of r esidual defects at 6 months depends mainly on the size of defects at 7 -10 days.