Right ventricular myocardial deoxygenation in patients with pulmonary artery hypertension

Karthigesh Sree Raman,Jennifer G Walker,Rebecca Perry,Michael Stokes,Susanna Proudman,Angela Walls,Ranjit Shah,Joseph B Selvanayagam,Richard J Woodman,David S Celermajer,Carmine G De Pasquale

doi:10.1186/s12968-020-00694-0

Abstract

BackgroundIn pulmonary arterial hypertension (PAH), progressive right ventricular (RV) dysfunction is believed to be largely secondary to RV ischaemia. A recent pilot study has demonstrated the feasibility of Oxygen-sensitive (OS) cardiovascular magnetic resonance (CMR) to detect in-vivo RV myocardial oxygenation. The aims of the present study therefore, were to assess the prevalence of RV myocardial ischaemia and relationship with RV myocardial interstitial changes in PAH patients with non-obstructive coronaries, and corelate with functional and haemodynamic parameters.MethodsWe prospectively recruited 42 patients with right heart catheter (RHC) proven PAH and 11 healthy age matched controls. The CMR examination involved standard functional imaging, OS-CMR imaging and native T1 mapping. An ΔOS-CMR signal intensity (SI) index (stress/rest signal intensity) was acquired at RV anterior, RV free-wall and RV inferior segments. T1 maps were acquired using Shortened Modified Look-Locker Inversion recovery (ShMOLLI) at the inferior RV segment.ResultsThe inferior RV ΔOS-CMR SI index was significantly lower in PAH patients compared with healthy controls (9.5 (– 7.4–42.8) vs 12.5 (9–24.6)%, p = 0.02). The inferior RV ΔOS-CMR SI had a significant correlation to RV inferior wall thickness (r = – 0.7, p < 0.001) and RHC mean pulmonary artery pressure (mPAP) (r = – 0.4, p = 0.02). Compared to healthy controls, patients with PAH had higher native T1 in the inferior RV wall: 1303 (1107–1612) vs 1232 (1159–1288)ms, p = 0.049. In addition, there was a significant difference in the inferior RV T1 values between the idiopathic PAH and systemic sclerosis associated PAH patients: 1242 (1107–1612) vs 1386 (1219–1552)ms, p = 0.007.ConclusionBlunted OS-CMR SI suggests the presence of in-vivo microvascular RV dysfunction in PAH patients. The native T1 in the inferior RV segments is significantly increased in the PAH patients, particularly among the systemic sclerosis associated PAH group.

Highlights

Pulmonary arterial hypertension (PAH) is a progressive disorder that affects both the pulmonary vasculature and the heart [1]
In a recent small proof of concept study, we have demonstrated the feasibility of OS-cardiovascular magnetic resonance (CMR) technique in detecting myocardial oxygenation abnormalities in the right ventricular (RV) of 20 patients with pulmonary arterial hypertension (PAH) [18]
The blunted oxygenation response was demonstrated in PAH patients who were stable on pulmonary vasodilator therapy and at an adaptive stage of PAH with non-obstructive epicardial coronaries, and was correlated inversely with RV wall thickness and right heart catheter (RHC) mean pulmonary artery pressure (mPAP)

Summary

Introduction

Pulmonary arterial hypertension (PAH) is a progressive disorder that affects both the pulmonary vasculature and the heart [1]. The increasing pulmonary artery pressure decreases the pressure gradient between the aorta and the RV, thereby reducing myocardial blood flow in the right coronary artery which, leads to myocardial ischemia [5, 6]. Whether the adaptive changes in the myocardial interstitium has any causal relationship to myocardial ischaemia in PAH patients remains unknown. In pulmonary arterial hypertension (PAH), progressive right ventricular (RV) dysfunction is believed to be largely secondary to RV ischaemia. The aims of the present study were to assess the prevalence of RV myocardial ischaemia and relationship with RV myocardial interstitial changes in PAH patients with non-obstructive coronaries, and corelate with functional and haemodynamic parameters

Objectives

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Results

Discussion

Conclusion