Left ventricular ischemia in pre-capillary pulmonary hypertension: a cardiovascular magnetic resonance study

Karthigesh Sree Raman; Ranjit Shah; Michael Stokes; Angela Walls; Richard J Woodman; Rajiv Ananthakrishna; Jennifer G Walker; Susanna Proudman; Peter M Steele; Carmine G De Pasquale; David S Celermajer; Joseph B Selvanayagam

doi:10.21037/cdt-20-698

Left ventricular ischemia in pre-capillary pulmonary hypertension: a cardiovascular magnetic resonance study

Cardiovasc Diagn Ther. 2020 Oct;10(5):1280-1292. doi: 10.21037/cdt-20-698.

Authors

Karthigesh Sree Raman^{1

2

3

4

5}, Ranjit Shah^{1

2

3}, Michael Stokes⁶, Angela Walls⁷, Richard J Woodman⁸, Rajiv Ananthakrishna^{1

2

3}, Jennifer G Walker², Susanna Proudman⁹, Peter M Steele⁶, Carmine G De Pasquale^{1

2}, David S Celermajer^{10

11}, Joseph B Selvanayagam^{1

2

3}

Affiliations

¹ College of Medicine and Public Health, Flinders University, Flinders, Australia.
² Flinders Medical Centre, Flinders, Australia.
³ Cardiac Imaging Research, South Australian Health & Medical Research Institute, Australia.
⁴ Whangarei Hospital, Northland District Health Board, Whangarei, New Zealand.
⁵ Department of Medicine (Northland Campus), Faculty of Medicine and Health Sciences, University of Auckland, Auckland, New Zealand.
⁶ Department of Cardiology, Royal Adelaide Hospital, Adelaide, South Australia, Australia.
⁷ Clinical Research and Imaging Centre, South Australian Health & Medical Research Institute, Adelaide, South Australia, Australia.
⁸ Flinders Centre of Epidemiology and Biostatistics, College of Medicine and Public Health, Flinders University, Flinders, Australia.
⁹ Discipline of Medicine, University of Adelaide, Adelaide, Australia.
¹⁰ Sydney Medical School, University of Sydney and Royal Prince Alfred Hospital, Sydney, Australia.
¹¹ Department of Cardiology, Royal Prince Alfred Hospital, Sydney, Australia.

Abstract

Background: Prognosis in pulmonary arterial hypertension (PAH) is largely dependent on right ventricular (RV) function. However, recent studies have suggested the presence of left ventricular (LV) dysfunction in PAH patients. The potential role of LV ischemia, as a contributor to progressive LV dysfunction, has not been systematically studied in PAH. We aim to assess the presence and extent of LV myocardial ischemia in patients with known PH and without obstructive coronary artery disease (CAD), using oxygen-sensitive (OS) cardiovascular magnetic resonance (CMR) and stress/rest CMR T1 mapping.

Methods: We prospectively recruited 28 patients with right heart catheter-proven PH and no significant CAD, 8 patients with known CAD and 11 normal age-matched controls (NC). OS-CMR images were acquired using a T2* sequence and T1 maps were acquired using Shortened Modified Look-Locker Inversion recovery (ShMOLLI) at rest and adenosine-induced stress vasodilatation; ΔOS-CMR signal intensity (SI) index (stress/rest SI) and ΔT1 reactivity (stress-rest/rest T1 mapping) were calculated.

Results: Global LV ΔOS SI index was significantly lower in PH patients compared with controls (11.1%±6.7% vs. 20.5%±10.5%, P=0.016), as was ΔT1 reactivity (5.2%±4.5% vs. 8.0%±2.9%, P=0.047). The ischemic segments of CAD patients had comparable ΔOS SI (10.3%±6.4% vs. 11.1%±6.7%, P=0.773) to PH patients, but lower ΔT1 reactivity (1.1%±4.2% vs. 5.2%±4.5%, P=0.036).

Conclusions: Decreased OS-CMR SI and T1 reactivity signify the presence of impaired myocardial oxygenation and vasodilatory response in PH patients. Given their unobstructed epicardial coronary arteries, this is likely secondary to coronary microvascular dysfunction (CMD).

Keywords: Pulmonary hypertension; cardiac magnetic resonance (CMR); coronary microvascular dysfunction (CMD); oxygen-sensitive cardiac magnetic resonance; stress/rest T1 mapping.