[Scintigraphic assessment of alterations in cardiopulmonary haemodynamics and renal functional activity in patients with endured coronary artery bypass grafting].

OBJECTIVE: By means of scintigraphic methods to assess alterations in cardiopulmonary haemodynamics and renal functional activity in patients with coronary artery disease (CAD) after endured coronary artery bypass grafting (CABG) performed in conditions of extracorporeal circulation (EC) and on the functioning heart.

MATERIAL AND METHODS: We examined a total of 40 patients presenting with CAD (mean age 54.90±1.12 years) after endured CABG. All patients were subdivided into 2 groups: Group One consisting of 20 patients subjected to CABG performed on the beating heart with the use of myocardial "stabilizer" "Acrobat" (Study Group) and Group Two also comprising 20 patients but undergoing surgery with the use of extracorporeal circulation (Comparison Group). All patients included into the study were subjected to radiocardiopulmonography with (99m)Tc-pertechnetate and dynamic radionuclide renoscintigraphy with (99m)Tc-DTPA before and 6-7 days after operative treatment.

RESULTS: In the early postoperative period after CABG, the patients of the both groups were found to have a significant increase in the minute volume, cardiac index, and circulation efficiency coefficient, accompanied by a significant decrease in the period of half-emptying of the left ventricle, thus suggesting improvement of LV contractility. Improved pulmonary microcirculation resulting from operative treatment in the compared groups of patients was confirmed by significantly shortened time of the indicator's passing through pulmonary vessels at the expense of both arterial (TAM) and venous (TVM) components. At the same time, a decrease in these parameters in the Study Group patients was more pronounced as compared with the Comparison Group patients. Thus, the means of the difference between the pre- and postoperative values of TAM and TVM in the Study Group amounted to 1.78 ± .40 s and 1.78 ± 0.32 s, and in the Comparison Group to 0.95 ± 0.22 s and 0.98 ± 0.16 s, respectively (p=0.029 and p=0.031 for TAM and TVM, respectively). The Comparison Group patients after CABG were found to have a significant decrease in the mean values of the total glomerular filtration rate (GFR) in combination with decelerated clearance of the indicator from blood. 30% of patients under the effect of nonpulsating blood flow developed relatively pronounced renal dysfunction (a decrease in the total GFR and/or GRF of one of the kidneys by 15% and more as compared with the initial level). Besides, these patients also demonstrated significant changes in the half-clearance of the radiopharmaceutical from the renal parenchyma and the index of cortical retention of the indicator on the both sides. Unlike the Comparison Group, in patients without EC the average values of the majority of parameters of renal filtration activity underwent no statistically significant alterations as compared with the baseline (prior to CABG) values.

CONCLUSION: Coronary artery bypass grafting without cardiac arrest exerts less pronounced negative influence upon the state of the renal function as compared with the open-heart surgery with extracorporeal circulation, which may partially be conditioned by statistically more significant positive dynamics of microcirculation in the system of pulmonary circulation under the effect of myocardial revascularization with the use of the myocardial stabilizer "off-pump".