Comparison and Effectiveness of Regadenoson versus Dipyridamole on Stress Electrocardiographic Changes during Positron Emission Tomography Evaluation of Patients with Hypertrophic Cardiomyopathy

摘要

Dipyridamole (Dip) is the most common vasodilator employed with positron emission tomography (PET) for the evaluation of individuals with hypertrophic cardiomyopathy (HC). The aim of this study was to evaluate whether PET quantification of regional myocardial perfusion (rMP), myocardial blood flow (MBF) and coronary flow reserve (CFR) are comparable between Dip and the newer vasodilator agent, Regadenoson (Reg) in HC. An additional aim was to evaluate the association between vasodilator-induced ST segment depression on ECG and myocardial flow in HC. N-13 ammonia PET was performed in 57 symptomatic HC patients at rest and during vasodilator stress (peak) with either Dip (0.56 mg/kg during 4-min infusion) or Reg (0.4 mg fixed bolus dose) for assessment of ECG, rMP (17 AHA-summed difference score [SDS]), MBF and CFR. The Dip and Reg groups consisted of 28 and 29 patients respectively. Baseline characteristics, including resting MBF (0.92 ± 0.22 vs. 0.89 ± 0.23 ml/min/g; P = 0.6) were similar between the Dip and Reg groups. During stress, the presence and severity of abnormal rMP (SDS 5.5 ± 5.5 vs. 5.8 ± 6.7, P=0.8), peak MBF (1.81 ± 0.44 vs. 1.82 ± 0.50 ml/min/g; P = 0.9) and CFR (2.02 ± 0.53 vs. 2.12 ± 0.12; P = 0.5) were comparable between Dip and Reg. Fewer patients exhibited side effects with Reg (2 vs.7; p=0.06). Vasodilator-induced ST segment depression showed a high specificity (~92%) but low sensitivity (~34%) to predict abnormal rMP (SDS ≥ 2). In conclusion, measurement of rMP and quantitative flow with PET is similar between Regadenoson and Dipyridamole in patients with symptomatic HC. Regadenoson is tolerated better than Dipyridamole and is easier to administer. Vasodilator-induced ST segment depression is a specific but non-sensitive marker for prediction of abnormal rMP in HC.