Using all-cause mortality to define severe RV dilation with RV/LV volume ratio

Area of Science:

• Cardiovascular Imaging and Diagnostics
• Pulmonary Hypertension Research
• Cardiac Structure and Function

Background:

• Right ventricular (RV) end-diastolic volume (EDV) to left ventricular (LV) EDV ratio via cardiovascular magnetic resonance imaging (CMR) is crucial for RV size assessment.
• Existing methods for evaluating RV dilation severity in pulmonary hypertension (PH) require refinement for better prognostic stratification.

Purpose of the Study:

• To establish severity partitions for RV dilation using the RV/LV volume ratio.
• To correlate RV dilation severity with mortality outcomes in patients with PH.
• To define clinically relevant cutoffs for mild, moderate, and severe RV dilation.

Main Methods:

• Utilized cardiovascular magnetic resonance imaging (CMR) cine short-axis sequences on a 1.5 T scanner.
• Analyzed RV and LV end-diastolic volumes (EDV) in 62 PH patients.
• Employed receiver-operating curve (ROC) analysis based on mortality to determine the optimal cutoff for severe RV dilation.

Main Results:

• Defined RV dilation categories: mild (1.27-1.69), moderate (1.70-2.29), and severe (≥2.30) based on the RV/LV volume ratio.
• Significant differences in RVEDV and RV ejection fraction were observed across the severity groups (p < 0.001).
• The severe RV dilation group exhibited significantly higher mortality compared to non-severe groups (p < 0.001).

Conclusions:

• The RV/LV volume ratio provides an outcome-based method for grading RV dilation severity in PH.
• This ratio effectively identifies severe RV dilation associated with increased mortality.
• The established partitions offer a valuable tool for prognostic assessment in PH patients.