Combined protocols for myocardial perfusion imaging in patients with hypertension

Objective - Patients diagnosed previously with hypertension submitted to ex ercise testing for myocardial scintigraphy often respond with excessive ele vation of the blood pressure, even when baseline blood pressure is normal, resulting in interruption of the test or false positive results for coronar y artery disease. The aim of this study was to evaluate the haemodynamic ch anges and the safety of the combined examination protocols of dipyridamole plus handgrip exercise and of dipyridamole plus symptom-limited exercise te sting on a treadmill in patients with hypertension. Methods and results - We performed scintigraphic myocardial single photon e mission computed tomography in 240 patients with hypertension as follows: i n 27 patients who were administered dipyridamole alone, in 126 patients who were administered dipyridamole and were also submitted to isometric handgr ip exercise and in 87 patients who were administered dipyridamole and were also submitted to treadmill, symptom-limited exercise (modified Bruce proto col). Mean systolic blood pressure, mean diastolic blood pressure and heart rate did not rise excessively in patients submitted to exercise testing (1 92 +/- 18 mm Hg, 106 +/- 14 mm Hg and 111 +/- 21 bpm for the dipyridamole p lus hand-grip group and 180 +/- 28 mm Hg, 104 +/- 10 mm Hg and 149 +/- 19 b pm for the dipyridamole plus treadmill group, respectively), with two patie nts from each exercise group presenting a maximum systolic blood pressure h igher than 220 mm Hg and no subsequent major cardiac complications (such as death, myocardial infarction, unstable angina or life-threatening arrhythm ia). Moreover, patients in these exercise groups experienced fewer non-card iac side effects than with dipyridamole alone, while attaining a good level of exercise stress. Conclusions - Both combined dipyridamole and exercise protocols for scintig raphic myocardial single photon emission computed tomography in patients wi th hypertension are safe and increase heart rate without an excessive eleva tion in blood pressure. Consequently, they can be recommended for clinical use. Dipyridamole combined with treadmill, symptom-limited exercise would b e the first choice, with dipyridamole and isometric handgrip exercise reser ved for patients with physical handicaps.