[Effects of the time interval between the first and second balloon inflations on ischemic preconditioning during...

Ischemic preconditioning is an attenuation of myocardial ischemia by repeated brief coronary occlusions observed during percutaneous transluminal coronary angioplasty (PTCA). The effects of the time delay between balloon inflations during PTCA on ischemic preconditioning were investigated in 48 patients with chronic stable angina but no rich collateral vessels. After successful predilatation, two 2-min balloon inflations were performed and the ST segment elevation in the electrocardiogram and chest pain were measured during each balloon inflation and compared. Patients were divided into three groups according to the interval between balloon inflations; 1 min (I1), 2 min (I2) and 5 min (I5). There were no significant differences in ST elevation (3.4, 3.2 and 3.7 mm) and chest pain during the first balloon inflation between these three groups. ST elevation and chest pain were decreased in groups I2 and I5 (2.6 and 2.8 mm) during the second balloon inflation compared with those during the first balloon inflation. However, there was no significant difference in ST elevation and chest pain during the first and second (3.7 mm) balloon inflations in group I1. ST elevation and chest pain were reduced more in group I5 than in I2. These results suggest that an interval of more than 2 min between balloon inflations is necessary to obtain the effect of ischemic preconditioning during PTCA.