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INTRODUCTION: Adenosine is the most widely used vasodilator stress agent for cardiovascular magnetic resonance (CMR) perfusion studies. With the standard dose of 140 mcg/kg/min some patients fail to demonstrate characteristic haemodynamic changes: a significant increase in heart rate (HR) and mild decrease in systolic blood pressure (SBP). Whether an increase in the rate of adenosine infusion would improve peripheral and, likely, coronary vasodilatation in those patients is unknown. The aim of the present study was to assess the tolerance and safety of a high-dose adenosine protocol in patients with inadequate haemodynamic response to the standard adenosine protocol when undergoing CMR perfusion imaging. METHODS: 98 consecutive patients with known or suspected coronary artery disease (CAD) underwent CMR perfusion imaging at 1.5 Tesla. Subjects were screened for contraindications to adenosine, and an electrocardiogram was performed prior to the scan. All patients initially received the standard adenosine protocol (140 mcg/kg/min for at least 3 minutes). If the haemodynamic response was inadequate (HR increase < 10 bpm or SBP decrease < 10 mmHg) then the infusion rate was increased up to a maximum of 210 mcg/kg/min (maximal infusion duration 7 minutes). RESULTS: All patients successfully completed the CMR scan. Of a total of 98 patients, 18 (18%) did not demonstrate evidence of a significant increase in HR or decrease in SBP under the standard adenosine infusion rate. Following the increase in the rate of infusion, 16 out of those 18 patients showed an adequate haemodynamic response. One patient of the standard infusion group and two patients of the high-dose group developed transient advanced AV block. Significantly more patients complained of chest pain in the high-dose group (61% vs. 29%, p = 0.009). On multivariate analysis, age > 65 years and ejection fraction < 57% were the only independent predictors of blunted haemodynamic responsiveness to adenosine. CONCLUSIONS: A substantial number of patients do not show adequate peripheral haemodynamic response to standard-dose adenosine stress during perfusion CMR imaging. Age and reduced ejection fraction are predictors of inadequate response to standard dose adenosine. A high-dose adenosine protocol (up to 210 mcg/kg/min) is well tolerated and results in adequate haemodynamic response in nearly all patients.

Original publication

DOI

10.1186/1532-429X-12-66

Type

Journal article

Journal

J Cardiovasc Magn Reson

Publication Date

16/11/2010

Volume

12

Keywords

Adenosine, Adolescent, Adult, Age Factors, Aged, Aged, 80 and over, Atrioventricular Block, Blood Pressure, Chest Pain, Chi-Square Distribution, Coronary Artery Disease, Coronary Circulation, Dose-Response Relationship, Drug, Electrocardiography, England, Feasibility Studies, Female, Heart Rate, Hemodynamics, Humans, Infusions, Intravenous, Logistic Models, Magnetic Resonance Imaging, Male, Middle Aged, Myocardial Perfusion Imaging, Predictive Value of Tests, Risk Assessment, Risk Factors, Stroke Volume, Vasodilation, Vasodilator Agents, Young Adult