Prognostic value of the right ventricular to left ventricular volume ratio on cardiac magnetic resonance imaging in predicting adverse outcomes for adults with pulmonary hypertension.

Background: Right ventricular (RV) performance impacts clinical outcomes across pulmonary hypertension (pH), yet noninvasive tools for early detection and risk stratification are limited. Cardiac MRI (CMR) derived RV to left ventricular (LV) volume ratio (RV/LV_vol ratio) provides a relative assessment of RV size by normalizing chamber size to the LV. However, its prognostic utility remains underexplored. In the present study, we investigate the association between the RV/LV_vol ratio and outcomes in patients with PH.

Methods: This prospective study included patients with PH (pulmonary arterial systolic pressure > 35 mmHg by echocardiography or mean pulmonary artery pressure > 20 mmHg on invasive right heart catheterization), who underwent CMR. Abnormal RV/LV_vol ratio cutoff (≥1.27) was applied and further tested using established gradation thresholds. The primary outcome was a composite of all-cause mortality and heart failure hospitalizations.

Results: Of 135 patients, 56 (41.5 %) had an abnormal RV/LV_vol ratio. After a mean follow-up of 1.9 ± 1.3 years, 75 patients experienced the primary outcome. Patients with an abnormal RV/LV_vol ratio had higher rates of the primary outcome (64.3 % vs 50.0 %, p = 0.02). After multivariable analysis adjusting for age and CMR indices, abnormal RV/LV_vol ratio was associated with a higher risk of the primary outcome (HR 1.81 [95 % CI 1.06-2.97]; p = 0.003). RV/LV_vol ratio added incremental prognostic value over age and traditional RV indices (global χ2 value increasing from 6.7 to 17.4, p = 0.006).

Conclusions: The RV/LV_vol ratio is a simple clinical tool associated with an increased risk of adverse outcomes in PH patients, offering prognostic information beyond traditional RV parameters.