Koroner Bypass Cerrahisinde Kullanılan İnternal Mammarian Arter, Radial Arter ve Safen Ven Greftlerinde Endotelyal Ox-LDL Reseptör Miktarlarının Karşılaştırılması

Abstract

Oğuz Arslantürk, MD. Comparison Of The OX-LDL Receptor Quantities In Internal Mammarian Artery, Radial Artery And Saphenous Vein Grafts In Coronary Bypass Surgery, Hacettepe University Faculty of Medicine, Department of Cardiovascular Surgery Graduate Thesis, Ankara 2020. The number one cause of death in the world is cardiovascular diseases, the leading cause of these is coronary artery disease and one of the most effective treatment methods is Coronary Artery Bypass Grafting (CABG) operation. The most commonly used grafts for CABG in the world and in our country are Internal Mammarian Artery (IMA), Radial Artery (RA) and Saphenous Vein (SV) grafts. The success of CABG depends on the long-term patency of the grafts and the prolongation of the patient's life span without impairing the quality of life. Atherosclerosis is primarily responsible for the failure of the grafts. With the increase in plasma LDL (low density lipoprotein) concentration, the risk of atherosclerosis increases in direct proportion. LDLR (LDL receptor) carries most of the LDL circulating cholesterol to hepatic and extrahepatic tissues by mediated endocytosis. LDLR dysfunction leads to retention of LDL in circulating blood and lipid accumulation in the vascular walls, eventually causing atherosclerosis. On the other hand, after LDL enters the vascular wall from the damaged endothelium, LDL is oxidized by free radicals and initiates the pathological process of atherosclerosis. The oxidized LDL is then absorbed by the fixed tissue macrophages via LOX-1 (lectin like low density lipoprotein receptor-1), thus transforming into lipid-filled foam cells. Foam cell groups accumulate under the endothelium and the first lesion of atherosclerosis becomes fatty streaks. In our study; we aimed to see the advantages of IMA, RA and SV over the LDLR, LOX-1 receptor. In our study; we consisted of 21 patients and decided to treat CABG, all of whom will be used in bypass surgery by means of IMA, RA and SV. We used the remaining vessel fragments during surgery. We used CD31 to identify endothelial cells. We evaluated endothelial LOX-1, LOX-1 expression from all cells produced in culture, and endothelial LDLR. At first, we could not see a significant relationship between the grafts and the receptor (p> 0,05). But as we looked into subgroups, we found striking results. In our study, we found that the percentage of CD31+&LOX-1 in IMA was higher in women than in men (p=0,019). Another result on gender is that we found a significantly lower percentage of CD31+&LDLR+ in the saphenous vein in women (p=0,002). Although there are studies stating that IMA and SV are worse in women compared to men, we found a guiding result for future studies. We found that the percentage of LOX-1 receptors in the saphenous vein was significantly higher in those with hypertension (p=0,040). We found that the percentage of receptors for CD31+&LDLR+ cells in the saphenous vein was low in patients with hypertension (p=0,014). We found that LOX-1 in the radial artery was significantly higher in smokers (p=0,015). This result demonstrated the radial artery-smoking relationship supporting the literature. We believe that to be a pioneer randomized controlled trials which will be held in the future. In our study, we found another striking result between HDL level and receptors. A strong positive correlation was found between the HDL level and the receptor percentage of CD31+/LOX-1+ cells in IMA (r=0,414, p=0,040). A positive significant correlation between HDL values and the percentage of LOX-1+ in the saphenous vein (r=0,609, P=0,005), a positive moderate correlation in the radial artery (r=0.488, P=0.029), a moderate positive correlation in IMA (r=0.530, P=0.016) was found. Studies have shown that modified HDL binds to LOX-1. All of the patients in our study are the group diagnosed with coronary artery disease. We think that these patients have dysfunctional HDL. We see that all graft types correlate the LOX-1+ receptor percentage in all cells in cell culture. There is no study in the literature that correlates the number of LOX-1 receptors in the saphenous vein, radial artery and IMA by means of HDL. We believe that our study will be a pioneer in this regard. The advantages of the grafts to each other will continue to be discussed for many years. We believe that we show a different view of the grafts used in coronary bypass surgery and we will guide new studies in the future.