Assessment of left ventricular function using radionuclide angiography after dipyridamole infusion

Thirty-six patients with significant coronary artery stenosis and no previous myocardial infarction and 25 subjects with normal coronary arteries underwent 99mTc RNV before and after coronary vasodilatation induced by dipyridamole, 0.75 mg/kg, given IV over 10 min. In subjects with normal coronary arteries, dipyridamole induced an increase in LVEF (from 66 +/- 8 to 76 +/- 8 percent; mean +/- SD; p less than 0.001); in patients with significant coronary artery stenosis (greater than or equal to 75 percent narrowing of at least one major vessel), dipyridamole injection did not affect LVEF (from 63 +/- 12 to 62 +/- 12 percent). In ten patients a complete, successful PTCA was performed and the RNV with the dipyridamole test repeated. The EF did not change with the dipyridamole test before PTCA (63 +/- 7 to 65 +/- 9 percent), but increased significantly after PTCA (62 +/- 11 to 70 +/- 9 percent; p less than 0.01). Sensitivity and specificity of EF changes after dipyridamole infusion were 75 and 76 percent, respectively. The test produced no major side effects or complications. Radionuclide angiography with dipyridamole helps to detect coronary artery stenosis and might be used to assess the effects of angioplasty on coronary flow reserve.