Classification and Predictors of Right Ventricular Functional Recovery in Pulmonary Arterial Hypertension

Area of Science:

• Cardiology
• Pulmonary Hypertension Research
• Medical Imaging Analysis

Background:

• Normative changes in right ventricular (RV) structure and function post-treatment for pulmonary arterial hypertension (PAH) are not well-defined.
• The study addresses the need to characterize treatment-associated functional recovery of the RV (RVFnRec).

Purpose of the Study:

• To assess the clinical relevance of a proposed definition for RV functional recovery (RVFnRec) in PAH patients.
• To identify specific structural and functional parameters that indicate successful RV recovery after treatment.

Main Methods:

• Evaluated 63 incident PAH patients using cardiac magnetic resonance imaging and right heart catheterization at diagnosis and post-treatment.
• Compared PAH patients with 62 healthy controls, utilizing invasive and noninvasive cardiopulmonary exercise testing.
• Defined RVFnRec using receiver operating curve analysis based on therapeutic changes in RV end-diastolic volume relative to peak oxygen consumption (VO2peak).

Main Results:

• A decrease in RV end-diastolic volume of -15 mL was the optimal cutoff for defining RVFnRec (AUC, 0.87; P=0.0001), nearing control values.
• RVFnRec was achieved by 35% of patients and was associated with significantly greater freedom from clinical worsening (P=0.006).
• An increase in RV compliance of 0.8 mL/mm Hg best predicted RVFnRec (AUC, 0.76; P=0.001), with RVFnRec patients showing greater increases in stroke volume and cardiac output during exercise.

Conclusions:

• RVFnRec, defined by a -15 mL decrease in RV end-diastolic volume, predicts exercise capacity, freedom from clinical worsening, and near-normalization of RV function.
• Therapeutic improvement in RV compliance is a superior predictor of RVFnRec compared to other afterload measures.
• RVFnRec is linked to an enhanced RV output reserve during exercise.