Vasoactive breathing manoeuvres as an effective coronary vasodilator in patients with suspected coronary artery disease: a prospective comparative oxygenation-sensitive CMR study

Aims In the assessment of myocardial ischaemia, vasoactive breathing manoeuvres have been proposed as a potential alternative to pharmacological vasodilator stress. However, it remains unclear whether the resultant physiological responses are comparable to those induced by adenosine in patients with suspected coronary artery disease (CAD). We sought to compare the myocardial oxygenation responses to a hyperventilation-breath hold (HVBH) manoeuvre with those elicited by adenosine, using oxygenation-sensitive cardiovascular magnetic resonance (OS-CMR). Methods and results Patients with suspected angina underwent 3-Tesla OS-CMR with (1) HVBH and (2) adenosine [140-210 μg/kg/min] prior to invasive coronary angiography. The primary outcome was the maximal percentage change in OS-CMR signal intensity for (1) HVBH (breathing-induced myocardial oxygenation reserve [B-MOREmax]) and (2) adenosine (adenosine-induced myocardial oxygenation reserve [A-MORE]). Significant CAD was defined as fractional flow reserve ≤0.80 in epicardial vessels ≥2mm diameter. From 53 prospectively recruited patients, 44 had complete, paired OS-CMR sequences (mean age 69±9 years, 75% male, CAD prevalence 59%). The HVBH manoeuvre elicited a myocardial oxygenation response comparable to that of adenosine (B-MOREmax 7.0±9.5% vs. A-MORE 8.6±12.3%, mean difference: -1.6% [-6.0%, 2.8%]; p=0.469), which remained similar at the segmental level following adjustment for age, sex, cardiovascular comorbidities, CAD and infarction (mean difference: -1.7% [-4.0%, 0.5%]; p=0.126). Conclusion In patients with suspected CAD, HVBH shows a comparable physiological response to adenosine. Future prospective studies evaluating the diagnostic accuracy of OS-CMR combined with vasoactive breathing manoeuvres for detecting significant CAD are warranted.