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    Body mass index as a determinant of postoperative morbidity
    (Cardiology Academic Press, 2013) Gurkan, Selami; Gur, Ozcan; Gur, Demet Ozkaramanli; Ege, Turan; Canbaz, Suat; Iscan, Sahin
    BACKGROUND: The impact of obesity on postoperative mortality and morbidity in coronary artery bypass grafting (CABG) operations is a widely studied but poorly defined topic. OBJECTIVE: To investigate the effect of body mass index (BMI) on in-hospital mortality and morbidity after isolated CABG surgery. METHODS: Prospectively collected data of a series of 1057 consecutive patients who underwent on-pump isolated CABG surgery were retrospectively analyzed. Patients were divided into five groups according to WHO BMI categorization (defined as underweight [BMI <20 kg/m(2)]; normal weight [BMI >= 20 kg/m(2) to <25 kg/m(2)]; overweight [BMI >= 25 kg/m(2) to <30 kg/m(2)]; obese, [BMI >= 30 kg/m(2) to <35 kg/m(2)]; and morbidly obese, [BMI >= 35 kg/m(2)]). RESULTS: Of 1057 patients, 13 patients (1.2%) were underweight, 298 (28.2%) were normal weight, 462 (43.7%) were overweight, 218 (20.6%) were obese and 66 (6.2%) were morbidly obese. The mean age was significantly lower in underweight patients, who were also more likely to be male. In contrast, obese and morbidly obese patients were older, and more likely to have comorbidities such as diabetes and hypertension. The incidence of postoperative bronchodilator use (P<0.001), leg wound infection (P=0.038), sternal dehiscence (P=0.039) and development of new-onset atrial fibrillation (P<0.001) was significantly higher in obese and morbidly obese groups. In contrast, postoperative prolonged ventilation (P<0.001), need for blood transfusions (P<0.001) and revision for bleeding (P=0.041), as well as gastrointestinal complications (P<0.001), were significantly higher in underweight patients. Multivariate logistic regression analysis showed that not BMI but female sex, older age and diabetes mellitis were independent risk factors for early mortality after CABG surgery. CONCLUSION: No effect of BMI on early postoperative mortality after CABG surgery could be demonstrated. However, in terms of morbidity, postoperative bleeding and revision for bleeding were increased in underweight patients while sternal dehiscence, wound infections and occurrence of atrial fibrillation were increased in obese and morbidly obese patients.
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    A comparison of the vasodilatory effects of verapamil, papaverine and nitroglycerin on isolated rat aorta
    (Baycinar Medical Publ-Baycinar Tibbi Yayincilik, 2013) Ege, Turan; Halici, Umit; Gur, Ozcan; Gurkan, Selami; Gur, Demet Ozkaramanli; Duran, Enver
    Background: This study aims to compare the vasodilatory effects of verapamil, papaverine and nitroglycerin on rat aortic preparations in in vitro isolated tissue bath system and to evaluate the role of vascular endothelium on vasodilatory responses of the isolated rat aorta samples. Methods: The thoracic aorta segments collected from 30 male Wistar rats (20 endothelialized and 20 de-endothelialized vascular rings for each drug in 2 mm wide strips, total number of 120 vascular rings) were suspended into the Krebs solution of the isolated tissue bath system. Phenylephrine was used to induce isometric contraction and tissue samples were treated with verapamil, papaverine and nitroglycerin separately to draw concentration-response curves of isometric vasodilatory responses. This procedure was repeated for de-endothelialized aorta samples. Results: Papaverine and verapamil induced vasodilatatory responses starting from the concentration of 10(-8) M and reached its maximum at concentration of 10(-3) M, while nitroglycerin induced vasodilation at lower concentrations starting from a concentration of 10(-12) M, reaching its maximum at 10(-6) M. Nitroglycerin was the most potent agent, followed by verapamil and papaverine. Efficacy analysis revealed that the most efficient agents were papaverine (140 +/- 6.7%), nitroglycerin (110.8 +/- 1.35%) and verapamil (99 +/- 4.14%), respectively. The results were similar in aorta samples without endothelium (p >= 0.05, F test). Conclusion: In this study examining isolated rat aorta, nitroglycerin was the most potent agent, while papaverine was the most efficient agent. Our study results showed that endothelium played no role in vasodilatation responses of these drugs.
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    Early results of monopolar versus bipolar radiofrequency ablation for atrial fibrillation during open heart surgery
    (Cardiology Academic Press, 2013) Gur, Ozcan; Gurkan, Selami; Gur, Demet Ozkaramanli; Cakir, Habib; Yuksel, Volkan; Huseyin, Serhat; Canbaz, Suat
    BACKROUND: In patients with atrial fibrillation (AF) for whom open heart surgery is scheduled, it is suggested to treat AF by ablation. OBJECTIVE: To compare the efficacy of monopolar and bipolar surgical radiofrequency ablation systems in patients undergoing concomitant open heart surgery and reveal the factors affecting the conversion to sinus rhythm. METHODS: Forty-three patients (19 male and 24 female) who underwent irrigated monopolar or bipolar radiofrequency ablation for persistent AF at concomitant cardiac surgery between 2007 and 2012 were included in the study. RESULTS: Monopolar ablation was performed in 24 and bipolar ablation was performed in 19 patients. Twenty of the 24 patients who underwent monopolar radiofrequency ablation and 15 of the 19 patients in the bipolar ablation group were in sinus rhythm at the three-month follow-up. There was no statistically significant difference between the two ablation procedures on the conversion of AF to sinus rhythm. When the effect of left atrial diameter on conversion to sinus rhythm was compared, left atrial diameter >60 mm was found to have pronounced negative influence on procedural success, while left atrial diameter <60 mm had no effect. CONCLUSION: A concomitant monopolar or bipolar modified Cox maze procedure during open heart surgery is equally effective technique for AF ablation at three months of follow up. Left atrial diameters >60 mm significantly reduced the rate of conversion to sinus rhythm.
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    The effect of distension pressure on endothelial injury and vasodilatation response in saphenous vein grafts: conversion of a bypass graft to a dead pipe
    (Termedia Publishing House Ltd, 2014) Gurkan, Selami; Gur, Ozcan; Yuksel, Volkan; Tastekin, Ebru; Huseyin, Serhat; Gur, Demet Ozkaramanli; Canbaz, Suat
    Introduction: Endothelial damage caused by high pressure applied for spasm relaxation during graft preparation is one of the most plausible theories explaining early graft failure. Aim of the study: We aimed to demonstrate the extent of endothelial damage in saphenous vein grafts distended to different pressure levels by using immunohistochemical methods and in vitro tissue baths. Material and methods: Saphenous vein grafts (SVGs) of 25 patients who underwent isolated elective CABG surgery were used in this study. By using a specific mechanism, SVGs were distended to five different pressure levels for two minutes: 0 mmHg, 50 mmHg, 100 mmHg, 200 mmHg, 300 mmHg. In vitro tissue baths and immunohistochemical examinations were performed. Results: None of the grafts distended to 300 mmHg pressure were functional in the tissue bath system. The relaxation response to carbachol of SVGs distended to 0, 50, 100 and 200 mmHg was 97.87 +/- 4.47%, 98.52 +/- 3.95%, 93.78 +/- 3.64%, and 30.87 +/- 4.11%, respectively. There were no statistically significant differences in terms of relaxation responses between samples distended to 0, 50, and 100 mmHg (p = 0.490). The relaxation response of samples distended to 200 mmHg was significantly decreased (p = 0.021). The endothelia of samples distended to 0 mmHg were almost intact in CD31 staining. Endothelial cell loss occurred at all tested distension pressures at different degrees. Conclusion: In vitro and immunohistochemical studies revealed that distending an SVG used for coronary artery bypass grafting with pressures of 100 mmHg or less results in less endothelial damage and increases graft patency.
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    The impact of body mass index on mortality and morbidity in patients undergoing isolated valve surgery
    (Baycinar Medical Publ-Baycinar Tibbi Yayincilik, 2013) Gur, Ozcan; Gurkan, Selami; Gur, Demet Ozkaramanli; Yuksel, Volkan; Huseyin, Serhat; Iscan, Sahin; Canbaz, Suat
    Background: This study aims to investigate the impact of body mass index (BMI) on early mortality and morbidity in patients undergoing isolated valve surgery. Methods: Between January 2004 and December 2012, medical records of 196 patients (115 males, 81 females; mean age 62.0 years; range 28 to 81 years) who underwent isolated valve surgery in our clinic with prospective follow-up data were retrospectively analyzed. The patients were divided into three groups according to their BMI values. Group 1 consisted of patients with a BMI <25 kg/m(2), group 2 consisted of patients with a BMI of >= 25 kg/m(2) to <30 kg/m(2) and group 3 consisted of patients with a BMI of >= 30 kg/m(2). Obesity was defined as a BMI of >= 30 kg/m(2). Groups were compared in terms of morbidity parameters including bleeding, respiratory, renal, neurological and sternal complications and in-hospital mortality. Results: Increased BMI was associated with increased diabetes prevalence and use of bronchodilator. According to postoperative data, there was no significant difference in duration of extubation, postoperative renal functions, neurological complications such as stroke and transient ischemic attack, length of intensive care unit or hospital stay among three groups. Obese patients in group 3 had significantly higher rates of respiratory complications including re-intubation (p=0.011) and postoperative bronchodilator need (p=0.034), sternal dehiscence and sternal infections (p=0.023) and in-hospital mortality (p=0.021). The bleeding complications were significantly higher in group 1 (p=0.004). Conclusion: Our study results suggest that obesity results in increased 30-day mortality and several morbidity parameters such as respiratory and sternal complications in patients undergoing isolated valve surgery.
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    Vasodilation Responses to Non-Selective ?-Adrenergic Blockage of Coronary Bypass Grafts in Diabetic and Non-Diabetic Patients: In Vitro Study
    (Medical Tribune Inc, 2015) Gurkan, Selami; Gur, Ozcan; Gur, Demet Ozkaramanli; Gocmez, Semil Selcen; Ege, Turan
    Background: Adrenergic tonus is increased in atherosclerotic coronary arteries. In this study, we aimed to demonstrate in vitro effects of phentolamine, a reversible nonselective alpha (a) adrenergic blocker, on coronary artery bypass grafts (CABG) and compare its effects in diabetic and nondiabetic patients. Methods: A total number of 30 patients (15 diabetic and 15 nondiabetic) who were assigned to elective CABG surgery were enrolled into the study. For both groups of patients, 16 internal mammarian artery (IMA) samples, 16 saphenous vein (SV) samples and 16 radial artery (RA) samples were collected and studied in the tissue bath system. The vasodilatation responses to increasing doses of phentolamine were recorded. Results: When grafts were compared in terms of amount of vasodilatation to phentolamine, IMA had the most prominent vasodilatation followed by RA and SV respectively. Although the vasodilatation responses in nondiabetic patients were numerically higher than diabetic patients, there was no statistically difference between the groups. Conclusion: Phentolamine, a nonselective a adrenergic blocker, is proven to have equal vasodilatory effects in diabetic and nondiabetic CABG grafts and can safely be used both intravenously and topically in the perioperative period.