Background: Controversy exists regarding inhibition of ischemic preconditioning in hyperlipidemic animals. In this study, we tested the hypothesis that hyperlipidemia inhibits the normal reduction of myocardial ischemia on repeated balloon inflations (BIs) during angioplasty.
Methods: We studied 33 patients undergoing coronary angioplasty. All underwent a minimum of three BIs. Patients were grouped according to the following plasma cholesterol levels: 13 patients had total cholesterol levels < 200 mg/dL (the normal cholesterol group); and 20 patients had total cholesterol levels ≥ 200 mg/dL (the elevated cholesterol group). Surface ST-segment elevations were recorded at the end of each BI.
Results: In the normal cholesterol group, the mean (± SD) ST-segment elevation decreased from 0.21 ± 0.15 mV during the first BI to 0.11 ± 0.11 mV during the third BI (p < 0.05). In the elevated cholesterol group, the respective decrease was from 0.18 ± 0.16 to 0.14 ± 0.15 mV (p = not significant) [between-group comparisons: F = 3.97; p = 0.02]. The decrease in ST-segment elevation was correlated with the total cholesterol levels (r = −0.48; p = 0.005), the low-density lipoprotein (LDL) cholesterol levels (r = −0.50; p = 0.003), and the high-density lipoprotein/LDL levels (r = 0.44; p = 0.01).
Conclusion: Hyperlipidemia prevents the normal reduction of myocardial ischemia on repeated BIs during angioplasty. This leads to the clinical implication that reduction of cholesterol plasma levels, apart from its other known benefits, could also have a beneficial effect on cardioprotection.