Right ventricular dysfunction in systemic sclerosis-associated pulmonary arterial hypertension.

Area of Science:

• Cardiology
• Pulmonology
• Rheumatology

Background:

• Systemic sclerosis–associated pulmonary artery hypertension (SScPAH) has a poorer prognosis than idiopathic pulmonary arterial hypertension (IPAH).
• Right ventricular (RV) failure is a common cause of mortality in SScPAH.
• The study investigates whether SScPAH imposes a greater pulmonary vascular load than IPAH, leading to worse RV function.

Purpose of the Study:

• To compare the pulmonary vascular load in SScPAH and systemic sclerosis–related pulmonary hypertension with interstitial lung disease (SSc-PH-ILD) versus IPAH.
• To assess RV contractile function and RV-pulmonary artery (PA) coupling in these patient groups.

Main Methods:

• Analysis of pulmonary artery pressures and flow in 282 patients with pulmonary hypertension (SScPAH, SSc-PH-ILD, IPAH).
• Measurement of RV pressure–volume loops in subsets of IPAH, SScPAH, and SSc without PH patients.
• Derivation of RV contractile indexes (Ees, Msw), RV load (Ea), and RV-PA coupling (Ees/Ea).

Main Results:

• Pulmonary vascular resistance and compliance products were similar across SScPAH, SSc-PH-ILD, and IPAH groups.
• RV afterload (pulmonary vascular resistance, Ea, pulmonary arterial compliance) was comparable between SScPAH and IPAH.
• RV contractility (Ees, Msw) was significantly depressed in SScPAH compared to IPAH, indicating worse intrinsic systolic function.
• RV-PA uncoupling (Ees/Ea) was more pronounced in SScPAH than IPAH, and even more so than in SSc patients without PH.

Conclusions:

• Right ventricular dysfunction is more severe in SScPAH compared to IPAH at similar levels of afterload.
• The enhanced RV dysfunction in SScPAH may stem from intrinsic systolic impairment rather than increased pulmonary vascular resistance or pulsatile loading.
• These findings highlight a potential mechanism for the worse prognosis observed in SScPAH.