Real-time risk stratification in acute pulmonary embolism: the utility of RV/LV diameter ratio

This study evaluates the prognostic utility of the RV/LV diameter ratio in predicting low cardiac index (CI) in patients with acute intermediate-risk PE.

We conducted a retrospective analysis of 112 patients with acute PE who underwent catheter-based therapies. The RV/LV diameter ratio was measured from standard axial views on computed tomography pulmonary angiogram (CTPA). Multivariable regression models were used to assess the relationship between the RV/LV diameter ratio and invasive hemodynamic parameters.

A total of 63 patients (56.3 %) had a low CI (≤2.2 L/min/m²). The optimal cut-off for the RV/LV ratio to predict low cardiac index was 1.0 (area under the curve: 0.64). In a multivariable model, the RV/LV ratio (every 0.1 increase) was a significant predictor of low CI (OR: 1.11, 95 % CI 1.01-1.23, p = 0.03). Patients with a high RV/LV ratio (>1.0) had a lower pre-procedure cardiac index (2.0 [IQR 1.7, 2.6] vs 2.7 [IQR 2.4, 3.0] L/min/m², p < 0.001), higher pre-procedure mPAP (34.0 [IQR 27.0, 41.0] mm Hg vs 28.0 [IQR 20.0, 35.0] mm Hg, p = 0.015), and were more likely to have a low cardiac index (65 % vs 3 %, p = 0.001). Every 0.1 increase in the ratio was associated with a 0.5 mm Hg increase in mPAP (p < 0.001) and a 0.05 L/min/m² lower cardiac index (p = 0.002). The RV/LV ratio demonstrated moderate sensitivity (64.5 %) and high specificity (84.2 %) for predicting low cardiac index.

The RV/LV diameter ratio offers real-time risk stratification and is a predictor of low cardiac index in patients with acute PE.