Intermediate-risk pulmonary embolism (PE) has variable outcomes. Current risk stratification models lack the positive predictive value to identify patients at highest risk of PE-related mortality. We identified intermediate-risk PE patients who underwent catheter-based interventions and right heart catheterization (RHC) and identified those with low cardiac index (CI < 2.2 L/min/m2). We utilized regression models to identify echocardiographic predictors of low CI and Kaplan Meier curve to evaluate PE-related mortality when stratified by the echocardiographic predictor. Of 174 intermediate-risk PE patients, 41 underwent RHC. Within this cohort, 46.3% had low CI. Univariable linear regression identified right ventricular outflow tract velocity time integral (RVOT VTI), right/left ventricular ratio, S prime, inferior vena cava diameter, and pulmonary artery systolic pressure as potential predictors of low CI. Multivariable linear regression identified RVOT VTI as significant predictor of low CI (β coefficient 0.124, 95% confidence interval [CI]: 0.01-0.24, P = .034). Right ventricular outflow tract velocity time integral <9.5 cm was associated with increased PE-related mortality, P = .002. A substantial proportion of intermediate-risk PE patients referred for catheter-based interventions had low CI despite normotension. Right ventricular outflow tract velocity time integral was a significant predictor of low CI. Low RVOT VTI was associated with increased PE-related mortality.
Introduction: Pulmonary embolism (PE) is associated with significant acute morbidity, mortality, and long term functional limitations. There is paucity of data on acute and short term functional assessment after acute PE. Hypothesis: Functional capacity will improve from baseline to follow up among patients with acute PE. Methods: We prospectively analyzed patients who underwent evaluation by the pulmonary embolism response team (PERT) at Loyola University Medical Center between 2016 and 2018. We included patients with acute PE who underwent six-minute walk test (6MWT) at discharge and during outpatient follow up (50±72 days post discharge). We collected demographic and clinical characteristics. We used paired sampled t-test to compare continuous variables. Results: Among the 204 patients evaluated by PERT, 38 patients (18.6%) underwent 6MWT at baseline and follow up. Patients were classified as low risk (6 patients), submassive (29 patients), and massive (3 patients). Mean age was 61.3±14.2, 50% were female, 60.5% were white, 26.3% were black, 29% had cancer, and 68.4% had concomitant DVT, mean BMI 36.4±10.3, and mean PESI score was 96.8+44.4. Overall the mean 6MWT distance increased significantly from a baseline of 726.9±73.7 feet to 1042±72.8 feet at follow up (p<0.001). Low risk (786±204 to 1115.8+177.6 p=0.63), Submassive (700.2±85 to 995.6±82.8 p<0.001), and Massive PE (859±261.7 to 1343.3±307 p=0.168) groups all demonstrated improvement in 6MWT distance. Conclusions: Functional capacity as measured by 6MWT significantly improved during follow up after acute PE. Future studies are needed to determine predictors of favorable functional outcome and best treatment strategies.
