title: Comparison and effectiveness of regadenoson versus dipyridamole on stress electrocardiographic changes during positron emission tomography evaluation of patients with hypertrophic cardiomyopathy.
abstract: Dipyridamole is the most common vasodilator used with positron emission tomography for the evaluation of patients with hypertrophic cardiomyopathy (HC). The aim of this study was to evaluate whether positron emission tomographic quantification of regional myocardial perfusion (rMP), myocardial blood flow (MBF), and coronary flow reserve are comparable between dipyridamole and the newer vasodilator regadenoson in HC. An additional aim was to evaluate the association between vasodilator-induced ST-segment depression on electrocardiography and myocardial flow in HC. Nitrogen-13 ammonia positron emission tomography was performed in 57 patients with symptomatic HC at rest and during vasodilator stress (peak) with either dipyridamole (0.56 mg/kg during 4-minute infusion) or regadenoson (0.4 mg fixed bolus dose) for assessment of electrocardiographic findings, rMP (17-segment American Heart Association summed difference score), MBF, and coronary flow reserve. The dipyridamole and regadenoson groups consisted of 28 and 29 patients respectively. Baseline characteristics, including rest MBF (0.92 ± 0.22 vs 0.89 ± 0.23 ml/min/g, p = 0.60), were similar between the 2 groups. During stress, the presence and severity of abnormal rMP (summed difference score 5.5 ± 5.5 vs 5.8 ± 6.7, p = 0.80), peak MBF (1.81 ± 0.44 vs 1.82 ± 0.50 ml/min/g, p = 0.90), and coronary flow reserve (2.02 ± 0.53 vs 2.12 ± 0.12, p = 0.50) were comparable between the dipyridamole and regadenoson groups. Fewer patients exhibited side effects with regadenoson (2 vs 7, p = 0.06). Vasodilator-induced ST-segment depression showed high specificity (about 92%) but low sensitivity (about 34%) to predict abnormal rMP (summed difference score ≥2). In conclusion, measurement of rMP and quantitative flow with positron emission tomography 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 nonsensitive marker for the prediction of abnormal rMP in patients with HC.
authors: Department of Radiology, Johns Hopkins Medical Institutions, Baltimore, Maryland, USA. pbravov1@jhmi.edu
authors: Paco E
authors: PE
authors: Bravo
authors: Iraklis
authors: I
authors: Pozios
authors: Aurélio
authors: A
authors: Pinheiro
authors: Jennifer
authors: J
authors: Merrill
authors: Benjamin M W
authors: BM
authors: Tsui
authors: Richard L
authors: RL
authors: Wahl
authors: Frank M
authors: FM
authors: Bengel
authors: M Roselle
authors: MR
authors: Abraham
authors: Theodore P
authors: TP
authors: Abraham
mesh_terms: D058917:Adenosine A2 Receptor Antagonists / Q000008:administration & dosage; D002312:Cardiomyopathy, Hypertrophic / Q000175:diagnosis* / Q000503:physiopathology; D003326:Coronary Circulation / Q000187:drug effects*; D004176:Dipyridamole / Q000008:administration & dosage; D004562:Electrocardiography / Q000187:drug effects*; D005080:Exercise Test / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007275:Injections, Intravenous; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000379:methods*; D011687:Purines / Q000009:adverse effects; D011720:Pyrazoles / Q000009:adverse effects; D012372:ROC Curve; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012720:Severity of Illness Index; D013318:Stroke Volume / Q000187:drug effects; D014665:Vasodilator Agents / Q000008:administration & dosage
chemical_list: D058917:Adenosine A2 Receptor Antagonists; D011687:Purines; D011720:Pyrazoles; D014665:Vasodilator Agents; C430916:regadenoson; D004176:Dipyridamole