Clinical relevance of right ventricular diastolic stiffness in pulmonary hypertension

Abstract

Aim: Right ventricular (RV) diastolic-stiffness is increased in pulmonary arterial hypertension (PAH) patients. We investigated whether RV diastolic-stiffness is associated with clinical progression and assessed the contribution of RV wall-thickness to RV systolic and diastolic-stiffness.

Methods: Using single-beat pressure-volume-analyses, we determined RV end-systolic-elastance (Ees), arterial-elastance (Ea), RV-arterial-coupling (Ees/Ea), and RV end-diastolic-elastance (stiffness,Eed) in controls (n=15), baseline PAH (n=63) and treated PAH-patients (survival>5 years, n=22, and survival<5 years, n=23).

Results: We observed an association between Eed and clinical progression, with baseline Eed>0.53 mmHg/ml associated with worse prognosis (age-corrected hazard-ratio 0.27, p=0.02). In treated patients, Eed was higher in patients with survival<5 years than in patients with survival>5 years (0.91±0.50 vs. 0.53±0.33 mmHg/ml, p<0.01)Wall-thickness

corrected Eed-values in PAH-patients with survival>5 years were not different from control values (0.76±0.47 vs. controls 0.60±0.41 mmHg/ml, ns), whereas in patients with survival<5 years, values were significantly higher (1.52±0.91 mmHg/ml, p<0.05 vs. controls).

Conclusions: RV diastolic-stiffness is related to clinical progression in both baseline and treated PAH patients. RV diastolic-stiffness is explained by the increased wall-thickness in patients with >5years survival, but not in <5years survival patients. This suggests that intrinsic myocardial changes play a distinctive role in explaining RV diastolic-stiffness in different PAH stages.