P5262Subclinical myocardial abnormalities in systemic sclerosis-associated versus non-connective tissue disease pulmonary hypertension by CMR multiparametric mapping
Authors: Brown J , Norrington K , Kotecha T , Martinez-Naharro A , Fayed H , Teresi L , Denton C , Schreiber B , Fontana M , Kellman P , Coghlan J , Knight D S 
Published: October 2019

Abstract

Introduction
Scleroderma (SSc)-associated pulmonary arterial hypertension (PAH) has the worst prognosis of all PAH subtypes despite having relatively more favourable haemodynamic and cardiac functional profiles. Myocardial abnormalities in SSc have been demonstrated by cardiovascular magnetic resonance (CMR) multiparametric tissue mapping. However, myocardial tissue characterisation studies across distinct PAH subtypes including SSc are limited.

Purpose
We compared indices of tissue characterisation by CMR multiparametric mapping between patients with SSc with and without PAH, non-connective tissue disease pulmonary hypertension (non-CTD PH) and healthy volunteers.

Methods
One-hundred and thirty-six patients underwent a CMR study over a 30-month period: 104 patients with systemic sclerosis, of whom 39 had SSc-PAH and 65 had no PH; 32 patients with idiopathic PAH, chronic thromboembolic PH or portopulmonary PH (non-CTD PH group). Patients underwent comprehensive CMR tissue characterisation including quantification of native myocardial T1 (MOLLI), myocardial T2 and ECV from automatically generated tissue maps along with conventional late gadolinium enhancement (LGE) imaging. Twenty age-matched controls underwent the same CMR study protocol. Patients were assessed for PH by right heart catheterisation.

Results
Native myocardial T1 and myocardial T2 and myocardial ECV are significantly elevated in SSc-PAH versus non-CTD PH (all p<0.05, Figure 1) despite no differences in LV systolic function between these patient cohorts. Patients with SSc have similar degrees of elevated T1, T2 and ECV irrespective of the presence or absence of PAH, suggesting a diffuse myocardial process due to SSc itself. Both SSc sub-groups have significantly higher T1, T2 and ECV compared with controls (all p<0.05).
All patients with SSc were subdivided by the presence or absence of ventricular insertion point LGE. Even in the absence of LGE, T1, T2 and ECV were significantly higher in SSc patients versus controls (all p<0.001). However, the presence of focal insertional LGE in SSc was not associated with different burdens of interstitial disease, as defined by median ECV. This highlights the unique role of multiparametric tissue maps in assessing diffuse myocardial involvement beyond the identification of focal LGE.

Conclusion
Subclinical abnormalities of the myocardium can be detected by CMR multiparametric tissue mapping in patients with SSc. The higher native myocardial T1 and T2 along with the elevated ECV in SSc-PAH are likely to be accounted for by SSc involvement itself. Abnormalities of the myocardial architecture could be a potential contributory reason for the poorer outcomes in SSc-PAH versus non-CTD PH despite the more favourable haemodynamics and right heart function observed in the former patient sub-group. Further work should be directed at determining the prognostic capacity of these metrics in SSc-PAH.

Acknowledgement/Funding
British Heart Foundation, Action Pharmaceuticals Ltd