Cardiovascular Medicine and Cardiac Surgery

Renalase is an enzyme that mediates lowering of blood pressure by destroying catecholamines. Hypertension is one of the most common complications after coronary artery bypass (CABG) surgery, and this complication is usually averted by administration of sodium nitroprusside (SNP), which lowers blood pressure by dilating blood vessels through nitric oxide (NO). Thus, the aim of the present study is to examine the changes in renalase, catecholamine and nitric oxide (NO) before and after administration of sodium nitroprusside to lower blood pressure in patients developing hypertension following coronary artery bypass (CABG) surgery using biological samples collected in the first 6 to 8 hours, and at 24^th, 48^th and 72^nd hours and to find out its relations with certain hemodynamic parameters. The study registered 26 patients who developed hypertension in the first 6 to 8 hours after CABG, 12 patients who had normal blood pressure after CABG, and 22 healthy individuals. ELISA method was used to measure renalase concentrations and catecholamine levels, and nitric oxide levels were quantified by spectrophotometry. Renalase concentrations and NO levels of the patients who developed hypertension in the first 6 to 8 hours were found significantly lower and catecholamine levels were significantly higher than those in controls and cases who did not develop hypertension. After starting sodium nitroprusside (SNP) administration, these patients showed a statistically significant increase in renalase concentrations and NO levels and a noteworthy decrease in catecholamine levels at 6 to 8, 24, 48 and 72 hours. In addition, a slight increase was found in heart rate and decreases was recorded in the systolic arterial pressure (SAP), diastolic arterial pressure (DAP) and mean arterial pressure (MAP) following sodium nitroprusside administration. Consequently, the data obtained in this study suggest that administration of nitroprusside lowers the blood pressure by not only increasing NO production (vasodilation), but also elevating the quantities of the renalase enzyme, which destroys catecholamines. It is believed that addition of renalase to medications used to lower blood pressure in the future can help in preventing hypertension.