Is using metaproterenol sulfate reliable in hypertension management during the coronary artery bypass graft surgery in terms of graft patency?

Abstract

INTRODUCTION: Coronary artery bypass graft (CABG) surgery that is a basic revascularization method is used commonly and hypertension appears frequently during and after CABG operations. In the treatment of hypertension, metaproterenol sulfate (MS) is one of the main agents; however, the effects of this agent on grafts are not known at an adequate level. The aim of the present study was to determine whether MS could be used safely in CABG operations by examining its effects on coronary grafts. MATERIAL AND METHODS: This cross-sectional, prospective, experimental study was conducted at a University hospital. In this study, internal thoracic artery (ITA), radial artery (RA) and saphenous vein (SV) graft materials were studied in organ bath in patients who underwent CABG surgery between 2013 and 2016. In the organ bath, 10-6 phenylephrine was added to the grafts to ensure that the ITA, RA and SV grafts contracted submaximally. Then, by adding MS with the cumulative method, the resulting relaxation results were recorded and dose-response curves were created. The p < 0.05 was considered as significant. RESULTS: A total of 30 patients were included in the study. The average age of the participants was 59.3 (45–81) years. Minimum 1 and maximum 6 grafts (2.96 in average) were taken from all patients. Relaxation response was formed in the ITA at a rate of 40.49% ± 13.52, in the RA at a rate of 28.41% ± 9.08 and in the SV at a rate of 23.87% ± 8.36 by adding MS with the cumulative method. In the statistical work that was done by comparing the relaxation values among the SV grafts, ITA and RA grafts, it was determined that the efficacy of MS in the SV grafts was significantly lower when compared with the ITA and RA grafts. CONCLUSIONS: In the present study, it was concluded that the risk of developing vasospasm was low in all three grafts when MS was used in intraoperative and postoperative periods. However, in the long-term, this made us consider that better graft patency rates might be obtained. Multicenter in-vivo studies with larger patient groups are needed to support our findings.