Hyperventilation-breath-hold maneuver to detect ischemia by strain-encoded CMR: a pilot study to evaluate a needle-free stress protocol

Abstract

\n \n \n Type of funding sources: None.\n \n \n \n Safety concerns for gadolinium-containing contrast agents and pharmacological stressors, together with tremendous costs and inconsistent reimbursement modalities are still limiting a widespread application of CMR stress testing despite proven benefits. Like the effect of adenosine, hyperventilation-breath-hold-maneuver (HVBH) has demonstrated to induce myocardial vasodilation and might serve as a stressor to induce coronary steal with consecutive hypokinesia.\xa0\n \n \n \n To evaluate the diagnostic accuracy of a needle-free, ultrafast stress test to detect myocardial ischemia by strain-encoded CMR (fSENC) after HVBH.\n \n \n \n Patients referred for CMR stress testing underwent an extended protocol in order to evaluate three different stress forms: (1) Adenosine first-pass perfusion (Ad-FPP), (2) Adenosine-fSENC (Ad-fSENC) and (3) HVBH-fSENC. Diagnostic accuracy was assessed using quantitative coronary angiography as reference.\xa0\n \n \n \n One-hundred-twenty-two predominantly male patients (age 66\u2009±\u200911years; 80% men) suspected for obstructive CAD were enrolled. Ad-fSENC and HVBH-fSENC provided significantly better diagnostic accuracy than Ad-FPP, both on a patient-level (Ad-fSENC: sensitivity 82%[65-93], specificity 83%[73-90], p\u2009<\u20090.05; HVBH-fSENC: sensitivity 81%[64-93], specificity 86%[77-93], p\u2009<\u20090.05) and territory-level (Ad-fSENC: sensitivity 67%[52-80], specificity 93%[90-96], p\u2009<\u20090.05; HVBH-fSENC: sensitivity 63%[47-76], specificity 95%[91-97], p\u2009<\u20090.05). The stress response of longitudinal strain differs significantly between ischemic and non-ischemic segments to Adenosine (LSischemic\u2009=\u20090.6\u2009±\u20095.4%, LSnon-ischemic\u2009=\u20090.9\u2009±\u20092.7%, p\u2009<\u20090.05) and HVBH (LSischemic\u2009=\u20091.3\u2009±\u20093.8%, LSnon-ischemic=-0.3\u2009±\u20091.8%, p\u2009=\u20090.002). Stress test duration of HVBH-fSENC (t\u2009=\u200964\u2009±\u20092s) was significantly shortened compared to Ad-fSENC (t\u2009=\u2009184\u2009±\u200959s, p\u2009<\u20090.0001) or Ad-FPP (t\u2009=\u2009Ad-FPP: 172\u2009±\u200959s, p\u2009<\u20090.0001).\xa0\n \n \n \n Stress testing by HVBH-fSENC provides promising diagnostic accuracy to detect myocardial ischemia and is faster than established methods without the necessity to apply contrast agent or pharmacological stressors.\n