Thirty-six patients with significan...

Thirty-six patients with significant coronary artery stenosis and no previous myocardial infarction and 25 bring under rules with normal coronary arteries underwent [99msupTc] RNV before and after coronary vasodilatation induced according to dipyridamole, 0.75 mg/kg, given IV across 10 min. In enthralls with normal coronary arteries, dipyridamole induced an increase in LVEF (from 66 [+ or -] 8 to 76 [+ or -] 8 percent; mean [+ or -] SD; p<0001); in patients with significant coronary artery stenosis ([is greater than or equal to] 75 percent narrowing of at least united major vessel), dipyridamole injection did not affect LVEF (from 63 [+ or -] 12 to 62 [+ or -] 12 percent) In ten patients a undiminished successful PTCA was performed and the RNV with the dipyridamole standard repeated. The EF did not change with the dipyridamole example before PTCA (63 [+ or -] 7 to 65 [+ or -] 9 percent) if it be not that increased significantly after PTCA (62 [+ or -] 11 to 70 [+ or -] 9 percent; p<001) Sensitivity and specificity of EF changes after dipyridamole infusion were 75 and 76 percent respectively. The proof produced no major side efficiencys or complications. Radionuclide angiography with dipyridamole helps to find out coronary artery stenosis and might be used to assess the imports of angioplasty on coronary pour reserve.

Symptom-limited exercise is routinely used in conjunction with RNV for detection and evaluation of coronary artery disease (CAD),[1] as an increase in LVEF <5 percent is associated with a high probability of reduc myocardial reserve[2] An abnormal LV performance in patients with coronary artery stenosis, however, can be observ solely if the level of exercise is sufficient to bring into view adequate LV ischemia. Dipyridamole given IV has been adviseed as an alternative test to physical exercise for detecting myocardial ischemia.[3,4] It is presum that through dilating coronary resistance vessels the remedy causes inhomogeneity of blood roll on distribution and decreases blood stream toward areas supplied by stenotic arteries.[5-8]

Dipyridamole infusion furnishs potential advantages over exercise radionuclide angiography, as it bring intos movement artifacts and can also be used in patients who cannot achieve high flushs of exercise for any reason.

Accordingly, we examined the imports of dipyridamole infusion in the assessment of LV function in patients with coronary stenosis and in sway subjects using equilibrium radionuclide angiography.

MATERIAL AND METHODS

Patient Population

We studied 61 consecutive patients (46 men and 15 women ranging in age 38 to 74 years, mean [+ or -] SD 54 [+ or -] 9) undergoing diagnostic coronary arteriography. Of them, 34 had been evaluated for CAD in our institution (by clinical examination, ECG stres touchstone and Holter monitoring), and 27 were referr for RNV and coronary arteriography. Coronary arteriography was scheduled after RNV and was not cancelled, depending in succession scintigraphic study results. Of the 61 patients, 53 had a history of exertional chest pain and eight of atypical chest pain. No patients had angina at stillness Ten of these patients were studied at RNV before and one week after happy PTCA, as defined according to the task force of the AHA/ACC.[9]

Patients with diabetes mellitus, valvular heart disease, or cardiomyopathy were exclud from the studious mood Therapy with [unkeyable]-blocking agents, digoxin, and verapamil was discontinued at least six days before the thought Nitrates and nifedipine, and put drugs intos containing methylxanthines, were withdrawn at least 24 and 72 h before the thought respectively. In the subset of patients who underwent PTCA, nitrates, nifedipine, and aspin were the standard treatment. All physics but aspirin were discontinued 24 h prior to the study

All patients gave informed unison to the protocol, which had been approved through the institutional committee on human research.

Radionuclide Study

Electrocardiographically gated vital current pool cardiac imaging in frame fashion data acquisition was used to assess global and regional LV function and mass changes after in vivo RBC labeling with 25 mCi of IV [sup99mTc] pertechnetate. Each cogitation was performed using a small field of view (259 cm in diameter), an Anger camera (Siemens LEM ZLC) interfaced with a computer regularity (Digital, PDP 11/34). The gamma camera was positioned in 45[degrees] left anterior oblique position with 15[degrees] caudal tilt. A 2 x digital zoom was used. After 10 min of tracer equilibration, children pool images were acquired at stop and at the end of dipyridamole infusion. The imaging rate was 50 frames by second, or fps (or 20 ms/frame), with a gate tolerance of [+ or -] 5 percent of the cardiac period Care was taken to achive a similar number of deems per frame in the repress and dipyridamole studies, with a minimum of 150000 numbers per frame.

The LVEF was measured in succession the raw time activity wind by standard technique as previously described,[10] the accuracy and reproducibility of which have been reported.