Delayed protective effect of telmisartan on lung ischemia/reperfusion injury in valve replacement operations

The present study aimed to investigate the delayed protective effect of telmisartan on lung ischemic/reperfusion injury in patients undergoing heart valve replacement operations. In total, 180 patients diagnosed with rheumatic valve diseases were randomly divided into the telmisartan (T), captopril (C) and placebo (P) groups. In the telmisartan group, the patients were pretreated with telmisartan (1 mg/kg/day), at the time period 96-48 h before the operation, whereas in the C group, the patients were treated with captopril (1 mg/kg/day) at the time period 96-48 h prior to the operation control group. Each drug treatment group included a corresponding placebo treatment. The variables pulmonary vascular resistance (PVR) and A-aDO₂ were measured prior to CPB and at 1, 3, 6 and 12 h after CPB. Pulmonary neutrophil (PMN) count in the left and right atrium blood as well as SOD malondialdehyde (MDA), NO, angiotensin II (AngII) value in the left atrium blood, were measured 30 min prior to and after CPB. The PVR parameters of the telmisartan and captopril groups were significantly lower than those of the placebo group (P<0.05). The A-aDO₂ values in the telmisartan and captopril groups were significantly lower than those in the placebo group at 1, 3 and 6 h following CPB treatment. The difference between the right and left atrium blood PMN was significantly lower in the telmisartan and captopril intervention groups compared to that in the placebo group 30 min following CPB treatment. The left atrium blood SOD and NO values were significantly higher, whereas the MDA value was significantly lower in the telmisartan group compared to the control group 30 min following CPB treatment. As for AngII, there was no difference between the C and T groups, compared with the P group. In the two groups 30 min after treatment with CPB, 24 patients experienced varying degrees of cough, with the telmisartan group showing a significant difference (P<0.05). The hospitalization time was compared in the three groups of patients and it was found to be significantly shorter in the telmisartan group than the captopril and placebo groups (P<0.05). In conclusion, it was found that for the time period 96-48 h before heart valve replacement operations telmisartan (1 mg/kg/day) delayed the protective effect on lung ischemia/reperfusion injury in patients with rheumatic valve diseases. The results of the present study indicated that the protective effect may be associated with the increment of endogenetic NO and the enhanced ability against lipid peroxidation.