Hyperaemic effects of adenosine and dobutamine in heart failure with reduced ejection fraction: A quantitative perfusion CMR study

Aims In patients with heart failure with reduced ejection fraction (HFrEF), determining the aetiology of cardiac dysfunction has important therapeutic and prognostic implications. Cardiovascular magnetic resonance (CMR) enables comprehensive phenotyping of HFrEF; however, it remains uncertain whether the choice of pharmacological stress agent influences the hyperaemic response required for reliable ischaemia assessment. We sought to compare the hyperaemic effects of adenosine and dobutamine in patients with HFrEF using quantitative perfusion CMR. Methods and results Patients with HFrEF (left ventricular ejection fraction [LVEF] ≤ 40%) prospectively underwent 3-Tesla CMR comprising functional cine imaging, late gadolinium enhancement (LGE) and first-pass perfusion imaging at rest and during pharmacological stress with (1) adenosine [140-210μg/kg/min] and (2) dobutamine [10-30 µg/kg/min]. Perfusion maps were reconstructed inline with automated, pixel-wise quantification of myocardial blood flow (MBF). The hyperaemic response, defined by global myocardial perfusion reserve (MPR) was calculated as the quotient of stress and rest MBF and compared between stress protocols. Fifty-three patients with HFrEF (mean age 63 ± 10 years, 77% male, mean LVEF 36 ± 10%, infarction 59%, and non-ischaemic focal fibrosis 21%) with paired adenosine- and dobutamine-stress perfusion data were analysed. Compared with dobutamine, adenosine produced a higher global MPR (mean difference: +0.61 [95% CI: 0.35, 0.88], p < 0.001), which remained significant at the segmental level following adjustment for age, sex, type II diabetes, LVEF and LGE presence (mean difference: +0.63 [95% CI: 0.55, 0.71]; p < 0.001). Conclusions In patients with HFrEF, despite the greater haemodynamic response to dobutamine, adenosine induces a greater hyperaemic response; however, whether this impacts on the diagnostic assessment of ischaemia remains to be established (Trial registration: NCT03661827).