Endothelial Function and Hypoxic-Hyperoxic Preconditioning in Coronary Surgery with a Cardiopulmonary Bypass: Randomized Clinical Trial.

A hypoxic-hyperoxic preconditioning (HHP) may be associated with cardioprotection by reducing endothelial damage and a beneficial effect on postoperative outcome in patients undergoing cardiac surgery with cardiopulmonary bypass (CPB). Patients (n = 120) were randomly assigned to an HHP and a control group. A safe, inhaled oxygen fraction for the hypoxic preconditioning phase (10-14% oxygen for 10 min) was determined by measuring the anaerobic threshold. At the hyperoxic phase, a 75-80% oxygen fraction was used for 30 min. The cumulative frequency of postoperative complications was 14 (23.3%) in the HHP vs. 23 (41.1%), p = 0.041. The nitrate decreased after surgery by up to 20% in the HHP group and up to 38% in the control group. Endothelin-1 and nitric oxide metabolites were stable in HHP but remained low for more than 24 h in the control group. The endothelial damage markers appeared to be predictors of postoperative complications. The HHP with individual parameters based on the anaerobic threshold is a safe procedure, and it can reduce the frequency of postoperative complications. The endothelial damage markers appeared to be predictors of postoperative complications.

Influence of Hypoxic and Hyperoxic Preconditioning on Endothelial Function in a Model of Myocardial Ischemia-Reperfusion Injury with Cardiopulmonary Bypass (Experimental Study).

The aim of the experiment was to evaluate the effect of preconditioning based on changes in inspiratory oxygen fraction on endothelial function in the model of ischemia-reperfusion injury of the myocardium in the condition of cardiopulmonary bypass. The prospective randomized study included 32 rabbits divided into four groups: hypoxic preconditioning, hyperoxic preconditioning, hypoxic-hyperoxic preconditioning, and control group. All animals were anesthetized and mechanically ventilated. We provided preconditioning, then started cardiopulmonary bypass, followed by induced acute myocardial infarction (ischemia 45 min, reperfusion 120 min). We investigated endothelin-1, nitric oxide metabolites, asymmetric dimethylarginine during cardiopulmonary bypass: before ischemia, after ischemia, and after reperfusion. We performed light microscopy of myocardium, kidney, lungs, and gut mucosa. The endothelin-1 level was much higher in the control group than in all preconditioning groups after ischemia. The endothelin-1 even further increased after reperfusion. The total concentration of nitric oxide metabolites was significantly higher after all types of preconditioning compared with the control group. The light microscopy of the myocardium and other organs revealed a diminished damage extent in the hypoxic-hyperoxic preconditioning group as compared to the control group. Hypoxic-hyperoxic preconditioning helps to maintain the balance of nitric oxide metabolites, reduces endothelin-1 hyperproduction, and enforces organ protection.

Causes of repeated remodeling of left ventricle after Dor procedure.

OBJECTIVES: To reveal morphological factors causing unfavorable follow-up outcome of surgical treatment of patients with ischemic cardiomyopathy (ICMP) and with left ventricle (LV) aneurysm according to the data of intraoperative biopsies of LV myocardium and right atrium (RA) auricle. METHODS: The object of the study was to examine biopsy material of LV myocardium and RA auricle from 36 patients with ICMP. Clinical criteria of patients' inclusion into the study were: ESI LV >80 ml/m(2), EDP LV >30 mmHg, LV EF <40%, presence of akinetic and dyskinetic areas in LV, angina of II-IV class CCS, heart failure of II-IV class NYHA. The following morphometrical parameters were estimated for revelation of postoperative remodeling risk factors: parenchymal-stromal ratio (PSR), trophic index (TI), pericapillar diffusion zone (PDZ), Kernogan index (KI) and specific volume of granules of natriuretic factor (NUF) in atrial cardiomyocytes. RESULTS: In all the patients LV EF increased significantly (from 36.4+/-4.1% to 46.3+/-4.2%) (P<0.05) in the early postoperative period; LV EDI decreased (from 139.3+/-11.2 ml/m(2) to 108.4+/-8.9 ml/m(2)) (P<0.05). In the follow-up period (one year) all the patients were divided into two groups: in 28 patients (the 1st group) volume of the cavity, contractile function of LV remained satisfactory. In the other eight patients (the 2nd group) there was significant decrease of LV EF (up to 33.9+/-10.2%) due to increase of LV EDI [up to 129.2+/-10.1 ml/m(2) (P<0.05)]. Grade of MR preoperatively was 1.21+/-0.5 and 1.47+/-0.9, correspondingly, for the patients with positive and negative changes in the follow-up postoperative period. Drawing morphological parallels of postoperative heart remodeling in patients with ICMP showed that diffusive, lymphocytic-macrophage inflammatory infiltration of myocardial stroma in combination with severe fibrosis (PSR<1.5), low TI (<0.015) and greater value of PDZ (>1000 microm) and KI (>1.6) of LV myocardium are the factors connected with unfavorable follow-up results of surgical treatment. Moreover, we showed an inverse correlative relationship between content of NUF granules in the cardiomyocytes of RA auricle and the outcomes of the Dor procedure. CONCLUSIONS: Thus, a combination of the foregoing features is a morphological predictor of postoperative heart remodeling in patients with ICMP.