Role of collateral flow in a pharmacological stress test (a combination of low-dose dobutamine and a vasodilator) as a predictor of wall motion reversibility.

The role of collateral flow was evaluated in a pharmacological stress test [a combination of low-dose dobutamine (DOB) and a vasodilator] as a predictor of wall motion reversibility at rest after percutaneous transluminal coronary angioplasty (PTCA) using ultrafast computed tomography (UFCT). Segments with wall motion abnormalities before PTCA were divided into two groups; ie, either with or without collateral flow. Patients were scanned at rest for baseline and again after 5 min of intravenous administration of 4 micrograms/kg per min of DOB after nitroglycerin (0.3 mg sublingually) or isosorbide dinitrate (2.5 mg bolus intravenous injection). Three months after PTCA, patients were scanned again and wall motion was compared with the previous findings. In collateral-dependent segments, the sensitivity of the pharmacological stress test as a predictor of wall motion reversibility was 87.5% and the specificity was 83.3%. In collateral-independent segments, the sensitivity was only 41.7%, while the specificity was 95.2%. Our findings demonstrate that the pharmacological stress test we used satisfactorily predicted wall motion reversibility in collateral-dependent segments, but tended to underestimate wall motion reversibility in collateral-independent segments. Therefore, collateral flow may be an important factor in accurately predicting wall motion reversibility by this pharmacological stress test.