Enver Duran

Electrophysiological evaluation of phrenic nerve injury during cardiac surgery--a prospective, controlled, clinical study.

BackgroundAccording to some reports, left hemidiaphragmatic paralysis due to phrenic nerve injury may occur following cardiac surgery. The purpose of this study was to document the effects on phrenic nerve injury of whole body hypothermia, use of ice-slush around the heart and mammary artery harvesting.MethodsElectrophysiology of phrenic nerves was studied bilaterally in 78 subjects before and three weeks after cardiac or peripheral vascular surgery. In 49 patients, coronary artery bypass grafting (CABG) and heart valve replacement with moderate hypothermic (mean 28°C) cardiopulmonary bypass (CPB) were performed. In the other 29, CABG with beating heart was performed, or, in several cases, peripheral vascular surgery with normothermia.ResultsIn all patients, measurements of bilateral phrenic nerve function were within normal limits before surgery. Three weeks after surgery, left phrenic nerve function was absent in five patients in the CPB and hypothermia group (3 in CABG and 2 in valve replacement). No phrenic nerve dysfunction was observed after surgery in the CABG with beating heart (no CPB) or the peripheral vascular groups. Except in the five patients with left phrenic nerve paralysis, mean phrenic nerve conduction latency time (ms) and amplitude (mV) did not differ statistically before and after surgery in either group (p > 0.05).ConclusionsOur results indicate that CPB with hypothermia and local ice-slush application around the heart play a role in phrenic nerve injury following cardiac surgery. Furthermore, phrenic nerve injury during cardiac surgery occurred in 10.2 % of our patients (CABG with CPB plus valve surgery).

The Role of Inflammation in Atrial Fibrillation following Open Heart Surgery

This study investigated the role of systemic inflammation in the development of atrial fibrillation (AF) after coronary artery bypass grafting (CABG). CABG was performed using cardiopulmonary bypass in 77 patients. Pre-operative AF was present in six patients (7.8%) and post-operative AF developed in 13 (18.3%) of the 71 patients with pre-operative sinus rhythm. Post-operative mediastinal drainage was significantly increased in patients with post-operative AF compared with those with sinus rhythm. Plasma E-selectin, P-selectin and vascular cell adhesion molecule levels were not significantly different between patients with pre- and post-operative sinus rhythm, those with pre-operative sinus rhythm and post-operative AF, and those with pre- and post-operative AF. There were significant differences between pre-and post-operative C-reactive protein, interleukin (IL)-6 and IL-10 levels within all three groups, but no differences in these parameters between the groups. Thus, in all groups there were significant alterations in mediators indicative of systemic inflammation following CABG, but comparisons between the groups revealed no differences predictive of AF.

Analysis of C-Reactive Protein and Biochemical Parameters in Pericardial Fluid

This study was designed to examine the relationship between pericardial fluid and plasma CRP levels, and to alterations in other biochemical parameters in patients undergoing Coronary Artery Bypass Grafting (CABG). The study group consisted of 96 Coronary Artery Disease (CAD) patients who were referred to our clinic for a CABG procedure and from whom sufficient amount of pericardial fluid could be collected. The patients were classified into 3 groups: Stable Angina Pectoris (SAP) (n = 27), Unstable Angina Pectoris (USAP) (n = 36), and Post-Myocardial Infarction (PMI) (n = 33). Levels of CRP, glucose, albumin, total protein, Creatine Kinase (CK), Creatine Kinase-MB (CK-MB), and Lactate Dehydrogenase (LDH) were determined in pericardial fluid samples and in simultaneously collected blood samples from radial artery. The pericardial CRP and LDH levels in the PMI group were higher than in the SAP (p = 0.015 and p = 0.000, respectively) and USAP (p = 0.011, p = 0.047) groups. Serum CRP levels in USAP (p = 0.014) and PMI (p = 0.000) groups were higher than those in the SAP group. Pericardial albumin levels in the PMI group were higher than in the USAP group (p = 0.038). In all groups, the pericardial fluid/serum protein ratio was > 0.5, the LDL ratio was > 0.6, and pericardial fluid LDH concentrations were > 300 mg/dl. CRP level of pericardial fluid was significantly higher in the PMI group than in other groups. However, pericardial fluid LDH levels were higher than blood LDH levels in this group and were also higher than pericardial fluid LDH levels of other groups.

Excision of Aortic Vegetation in Brucella Endocarditis

A 19-year-old man with brucella endocarditis was treated by antimicrobial therapy and surgical excision of vegetation with preservation of the native aortic valve.

Evaluation of Iloprost to Prevent Vasospasm in Coronary Artery Bypass Grafts

This study assessed the efficacy of iloprost in relieving vasospasm in coronary artery bypass grafts. Radial artery (RA), left internal thoracic artery (LITA) and saphenous vein (SV) grafts were taken from 20 patients (13 men and seven women, mean age 63.8 years [range 48 − 74 years]) scheduled to undergo coronary artery bypass grafting. Ten 3 mm vascular rings were cut from each graft and kept under tension for at least 60 min. They were kept alive with 37°C oxygenated Krebs solution. Smooth muscle contraction was achieved with phenylephrine before iloprost was administered every 2 min, starting at a concentration of 10−9 mol/l and increasing in logarithmic increments to a concentration of 10−5 mol/l. The vasodilation response to iloprost started in all samples at a concentration of 10−9 mol/l and increased with each incremental increase in iloprost concentration up to 10−5 mol/l. These data suggest that local administration of iloprost has a role in relieving graft vasospasm during harvesting and preparation for coronary artery bypass grafting.

Effect of pericardial fluid pro-inflammatory cytokines on hemodynamic parameters.

We investigated the effects of pro-inflammatory cytokines of pericardial fluid on hemodynamic parameters in patients undergoing coronary artery surgery. Seventy-eight patients were included in the study and they were allocated to three groups: group 1, stable angina pectoris (SAP, n = 15); group 2, unstable angina pectoris (USAP, n = 34); group 3, post-myocardial infarction (PMI, n = 29). Pericardial fluid and arterial blood samples were obtained from all patients and interleukin (IL)-1beta, IL-2 receptor, IL-6, IL-8 and tumor necrosis factor-alpha (TNF-alpha) levels were measured. Pericardial IL-1beta concentration (pg/mL) was significantly higher in the USAP group (26.6 +/- 10.9) compared to the SAP (5.0 +/- 0.1) and PMI (5.8 +/- 1.0) groups. IL-2R, IL-6, IL-8 and TNF-alpha concentrations of pericardial fluid were significantly higher than serum in all groups; difference was more prominent in the PMI group compared to the SAP and the USAP groups. Serum IL-1beta concentrations (pg/mL) were significantly higher in the USAP group (21.8 +/- 3.4) compared to the SAP group (5.0 +/- 0.1) and the PMI group (5.4 +/- 1.6). Cardiac index (CI) before opening the pericardial sac was found to be lower in the USAP group (1.6 +/- 0.3 L/min/m2) compared to the SAP (2.2 +/- 0.5 L/min/m2) and the PMI (2.1 +/- 0.5 L/min/m2) groups (p = 0.028 and p = 0.011, respectively). In the USAP group, there was a relationship between reduction of CI and increase of IL-1beta levels in serum and pericardial fluid.

The effects of cardiopulmonary bypass on androgen hormones in coronary artery bypass surgery.

The effects of testosterone on coronary vasomotor regulation have been described by several recent reports. Here we investigated changes in serum androgen levels during and after cardiopulmonary bypass (CPB) in patients who had undergone coronary artery bypass surgery. Serum luteinizing hormone, free testosterone and dihydroepiandrestenedione sulphate (DHEA sulphate) levels were evaluated in 38 male coronary artery bypass surgery patients using a chemical immunoassay technique. All hormone levels were corrected to account for haemodilution. Serum-free testosterone level decreased significantly during weaning from CPB (from 15.7 ± 4.2 nmol/l to 6.2 ± 2.8 nmol/l), and an even greater decrease was observed in the first post-operative day (5.4 ± 3.1 nmol/l). On the seventh post-operative day, free testosterone levels reached a normal value (11.8 ± 5.5 nmol/l), although they were still significantly lower compared with the pre-operative value. There were slight alterations in serum DHEA sulphate levels, although the only significant decrease occurred from the first to the seventh day post-operation (from 4.7 ± 2.2 μmol/l to 3.7 ± 1.8 μmol/l, respectively). Serum luteinizing hormone levels were decreased during weaning from CPB (from 4.8 ± 2.1 mIU/ml to 3.9 ± 1.8 mIU/ml), but increased rapidly to the pre-operative value (5.5 ± 2.5 mIU/ml) at the first post-operative day. These results show that CPB affects serum luteinizing hormone, free testosterone and dihydroepiandrestenedione sulphate levels. The free testosterone level decreases significantly both during and after CPB surgery.

Cytokine Response in Lower Extremity Ischaemia/Reperfusion

We studied the local and systemic concentrations of pro-inflammatory cytokines produced during acute lower extremity ischaemia and following reperfusion in 19 patients undergoing thromboembolectomy of the femoral artery. Blood samples were taken from the femoral vein (local response) and radial artery (systemic response) in the ischaemic (baseline) phase, and 2, 12 and 24 h post-reperfusion. Associated lung injury was measured by the alveolar-arterial (A-a) oxygen gradient and post-reperfusion femoral vein plasma concentrations of creatinine kinase and lactic dehydrogenase were also measured. Local and systemic concentrations of interleukin (IL)-2 receptor and IL-6 (but not IL-1β) increased significantly after reperfusion. IL-8 concentration increased significantly in the radial artery. The high and progressively increasing concentration of IL-6 in the femoral vein suggests local production. The parallel increase in creatinine kinase concentration and A-a oxygen gradient indicates that IL-6 plays an important role in acute arterial occlusion and reperfusion injury.

Aspirin versus clopidogrel for synthetic graft patency after peripheral arterial bypass grafting.

Usually, aspirin used as an antiplatelet agent is thought to be sufficient to ensure graft patency after surgical bypass procedures. However, clopidogrel can also be considered as an alternative to aspirin. – 4 We have performed a preliminary fact-finding study in an attempt to compare the efficacies of aspirin and clopidogrel on long-term synthetic graft patency following peripheral arterial revascularisation. Seventy-six peripheral arterial bypass operations were performed in 54 patients using polytetrafluoroethylene synthetic grafts. Twelve aortafemoral bypass, 45 above-knee femoro-popliteal bypass, three ilio-femoral bypass, seven aorta-bi-femoral bypass (two cases in this latter group were aorta-bi-femoral plus femoro-popliteal bypass) were performed. Eight-mm ringless grafts in the aorta-femoral location and 6-mm full ringed grafts in the above-knee femoro-popliteal location were preferred. Twenty-eight patients who had 39 bypass procedures each received 300 mg single daily dose acetylsalicylic acid (Aspirin®, Bayer) and 26 patients who had 37 bypass procedures each received 75 mg single daily dose clopidogrel (Plavix®, Sanofi). Arterial examination consisted of peripheral arterial pulses and monthly evaluation of synthetic grafts and peripheral arteries using Doppler ultrasound. Early graft occlusion occurred in two patients within 30 days of operation and these were excluded from the study. Details of the patients, follow-up times, patency rates and complications are summarised in Table 1. The aspirin group was followed up for a mean of 11±4.0 months and the clopidogrel group for a mean of 7.2±3.9 months. Graft patency rate was 81% in the aspirin group and 84% in the clopidogrel group. The mean time to graft occlusion was 8.4±4.6 months in the aspirin group and 5.5±1.7 months in the clopidogrel group. The difference was not statistically significant. There were less unpleasant side effects in the clopidogrel group compared to the aspirin group. Nausea, vomiting, diarrhoea, rash and bleeding were observed in the aspirin group. Diarrhoea in one case and nausea and vomiting in one case were observed in the clopidogrel group. Graft occlusions occur as a result of thrombosis of the graft due to an insufficient peripheral arterial system and constriction at the proximal or distal arteries due to progression of the systemic atherosclerosis. Another pathology is intimal and neo-intimal hyperplasia in the suture line. Antiplatelet drugs as aspirin are used for the prevention of anastomotic neointimal fibrous hyperplasia. The effects of clopidogrel on ischaemic events were evaluated in the multicenter CAPRIE study and it was suggested that clopidogrel is more effective and safer than aspirin. However, in our study no clear difference was found between the efficacy of aspirin and clopidogrel. Although times of follow-up were not equal,

Autogenous arterial radial-basilic forearm looped transposition

We describe the use of radial artery as a conduit for arteriovenous hemodialysis access in the forearm. The advantages of this type of fistula are use of autogenous material and its localization because forearm fistula is easily cannulated and is more convenient for the patient. This fistula may be an alternative solution in selected hemodialysis patients for the difficult access in whom superficial arm veins are exhausted and lower extremity access is unsuitable.