Left and Right Ventricular Diameters Independently Predict Outcome in Intermediate and High-Risk Pulmonary Embolisms

BackgroundThe right to left ventricular diameter ratio (RV/LV) is a key imaging parameter used in risk stratification of pulmonary embolism. While having RV/LV above a cutoff value of 0.9 is usually attributed to pathological RV dilatation, we hypothesized that increased RV/LV may also be attributable to reduced LV filling. We aimed to examine RV and LV diameters as independent predictors of PE outcomes in patients presenting with intermediate or high-risk PE. MethodsWe measured RV and LV diameters on pre-intervention echocardiograms performed on 164 subjects presenting at or referred to our center for large PE requiring surgical thrombectomy, venoarterial extracorporeal membrane oxygenation (VA-ECMO), or catheter directed thrombectomy. ResultsThe primary outcome of death (n=3) or survival of cardiopulmonary resuscitation (CPR) (n=11) was met in 14 subjects. Smaller LV diameter and larger RV diameter were each demonstrated to be independent predictors of the primary outcome. LV diameter of <3.6 cm, RV diameter >5.0 cm, and RV/LV ratio of >1.2 were the cutoff values for each parameter most associated with the primary outcome. ConclusionThis study demonstrates that, in addition to dilated RV, small LV is an independent risk factor of death or need for CPR in hemodynamically significant PE treated with advanced therapies. This finding suggests that the predictive value of RV/LV for PE outcomes may be attributed to both RV enlargement and reduced LV filling.