Does repeated balloon inflation during coronary angioplasty induce ischemic tolerance? Analysis based on regional work.

It has been reported that repeated brief balloon inflation during coronary angioplasty (PTCA) alleviates myocardial dysfunction. However, it has also been reported that PTCA does not induce ischemic tolerance. Six patients with stable angina pectoris were recruited for this study. They were scheduled for PTCA to a significant stenosis of the proximal left anterior descending artery (LAD). All patients had single-vessel coronary artery disease without angiographic evidence of collateral circulation and with normal wall motion. After the stenosis of LAD was dilated by a 30-s inflation, 60 s of balloon inflation was performed five times at 60-s intervals. Left ventricular regional work was determined in the first and fifth inflations, and the data were compared. Regional work of the interventricular septum decreased immediately after the balloon inflation (the first inflation: 5.3 +/- 1.0 --> 0.6 +/- 0.2 mJ/cm3; fifth inflation; 5.3 +/- 1.0 --> 0.6 +/- 0.3 mJ/cm3) and no statistically significant differences were found between the first and fifth inflations. After balloon deflation, the time required for the recovery of regional work was 30s in the fifth inflation, compared with 40 s in the first inflation (at 30 s after deflation, first inflation: 3.6 +/- 1.3 mJ/cm3; fifth inflation: 5.2 +/- 1.2 mJ/cm3). Although repeated balloon inflation did not change the amount of reduction in regional work, it improved the postischemic recovery of regional work. These results suggest ischemic tolerance.