Cardiorespiratory efficacy of thrombolytic therapy in acute massive pulmonary embolism: identification of predictive factors

The aim of this study was to evaluate the contribution of clinical, angiogr aphic and haemodynamic findings in predicting the cardiorespiratory efficac y of thrombolytic therapy in acute massive pulmonary embolism, Haemodynamic measurements and pulmonary angiography were performed before ( H-0) and 12 h after (H-12) initiating thrombolytic therapy in 23 patients w ith acute massive pulmonary embolism (Miller index greater than or equal to 20/34), and free of prior cardiopulmonary disease. Patients were divided i nto two groups according to the variation in oxygen delivery (Delta DO2) be tween H-0 and H-12: Delta DO2 >20% (responders, n=10) and Delta DO2 less th an or equal to 20% (nonresponders, n=13). Before thrombolysis, clinical and angiographic findings were similar in bot h groups. Mean right atrial pressure (RAP) and total pulmonary (vascular) r esistance (TPR) were higher, while cardiac index (CT), DO2 and mixed venous oxygen saturation (Sv,O-2) were lower in responders, DO2 and Sv,O-2 were m ore closely correlated with Delta DO2 than RAP, TPR and CI, Eight out of th e 10 responders and two out of the 13 nonresponders had an Sv,O-2 less than or equal to 55%, while nine of the responders and two of the nonresponders had a DO2 <350 mL.min(-1).m(-2). In conclusion, the initial oxygen delivery and mixed venous oxygen saturati on may predict the cardiorespiratory efficacy of thrombolytic therapy in ac ute massive pulmonary embolism. When pulmonary angiography is performed, me asurement of mixed venous oxygen saturation may be a simple method by which to select patients for thrombolytic therapy.