İsa Durmaz

Prophylactic dialysis in patients with renal dysfunction undergoing on-pump coronary artery bypass surgery

BACKGROUND Preoperative creatinine values higher than 2.5 mg/dL are associated with markedly increased risk for both mortality and morbidity in patients undergoing coronary artery bypass surgery. We aimed to determine the effects of prophylactic perioperative hemodialysis on operative outcome in patients with nondialysis-dependent moderate renal dysfunction. METHODS Forty-four adult patients with creatinine levels greater than 2.5 mg/dL but not requiring dialysis underwent coronary artery bypass surgery with cardiopulmonary bypass. The patients were randomly divided into two groups. In group 1 (dialysis group, 21 patients), perioperative prophylactic hemodialysis was performed in all patients. Group 2 (23 patients) was taken as a control group and hemodialysis was performed only if postoperative acute renal failure was diagnosed. RESULTS The hospital mortality was 4.8% (1 patient) in the dialysis group, and 30.4% (7 patients) in the control group (p = 0.048). Postoperative acute renal failure requiring hemodialysis was seen in 1 patient (4.8%) in the dialysis group and in 8 patients (34.8%) in the control group (p = 0.023). Thirty-three postoperative complications were observed in the control group for an early morbidity of 52.2% (12 patients) and 13 complications occurred in 8 patients in the dialysis group (38.1%). The average length of the intensive care unit and postoperative hospital stay were shorter in the dialysis group than in the control group (p = 0.005 and p = 0.023, respectively). CONCLUSIONS Preoperative creatinine levels higher than 2.5 mg/dL, increase the risk of mortality and the development of acute renal failure and prolong the length of hospital stay after on-pump coronary artery bypass surgery. Perioperative prophylactic hemodialysis decreases both operative mortality and morbidity in these high-risk patients.

Effect of pulsatile flow during cardiopulmonary bypass on thyroid hormone metabolism

Changes in thyroid hormone levels during and after cardiopulmonary bypass (CPB) are well documented. However, little is known about the effects of pulsatile flow during CPB on thyroid hormone metabolism. To examine the effect of flow pattern, a prospective study was carried out using 30 patients undergoing coronary artery bypass grafting. Fifteen patients had pulsatile flow during CPB and 15, nonpulsatile flow. Serum samples were obtained preoperatively, during bypass, and at 2 and 24 hours postoperatively. Thyroid-stimulating hormone, thyroxine (T4), triiodothyronine (T3), free T4, and free T3 levels were measured by radioimmunoassay. All measured hormone levels except free T4 and thyroid-stimulating hormone decreased after the initiation of CPB. There were no differences in preoperative values between the two groups. However, levels of T3 and free T3 during and after CPB showed a significant difference between the two groups, with a smaller decrease in patients in whom pulsatile flow was used during bypass (p < 0.05). Thyroxine, and thyroid-stimulating hormone free T4 values showed no difference between the two groups at any sampling time. These data provide support for the use of pulsatile flow during CPB to establish a more physiologic state and maintain better thyroid hormone metabolism.

Comparison of different dose regimens of enoxaparin in deep vein thrombosis therapy in pregnancy

IntroductionPregnant women have a higher risk of developing deep vein thrombosis (DVT) and consequent thrombogenic events, including pulmonary embolisms. Low-molecular-weight heparin (LMWH) products have been shown to successfully treat DVT with few significant side effects. The purpose of this study was to compare the effects of two dose regimens of enoxaparin (a LMWH) in the management of DVT in pregnancy.MethodsA total of 35 pregnant patients with DVT were enrolled in this study. As first-line anticoagulation therapy, patients were administered an intravenous unfractionated heparin infusion for 5 days, followed by a subcutaneous injection of enoxaparin 1 mg/kg twice a day until discharge. The enoxaparin therapy continued at home with 1 mg/kg twice a day for 18 patients (group I) and 1.5 mg/kg once a day for the other 17 patients (group II). Enoxaparin was discontinued 12–24 hours before delivery and restarted within 8-12 hours after delivery. Warfarin was given as adjuvant therapy along with enoxaparin in the post-partum period. Enoxaparin was discontinued when an international normalised ratio of 2 or above was reached. Differences between the two groups in terms of therapy response, complications and efficacy were recorded.ResultsThrombophilic disease was observed in three patients in each group. The iliac vein had the highest incidence of DVT in both groups. During therapy, two patients in group I were diagnosed with a mild haemorrhage; one patient (in group II) had abortion. There were no significant differences between groups in terms of recanalisation (measured by venous ultrasonography examination), post-thrombotic symptoms or safety parameters.ConclusionEnoxaparin can be used safely in DVT therapy during pregnancy. Our results indicate that therapy consisting of a single daily dose of 1.5 mg/kg enoxaparin is as effective as twice-daily administration.

Bicuspid mitral bioprosthesis.

A bicuspid mitral bioprosthesis was prepared by mounting glutaraldehyde-processed porcine pericardium onto commercially available Brownlee-Yates stents. The bioprostheses were inserted into 17 dogs. Haemodynamic performance and long-term function of the valve was assessed. Of the 11 animals in the survival group, eight died within the 24-72 hour postoperative period. The clinical picture of these animals revealed progressive left ventricular failure although the bioprostheses were tested and found competent both at insertion and at necropsy. The causes of the late deaths were deterioration of the porcine pericardium in two, and cerebral embolism in another. The acute haemodynamic studies showed a significantly high closing reflux from within the tubular bioprosthesis, and this reflux was found to be inherent in the design. It was concluded that any stented bicuspid valve where the stent assumes the function of the papillary muscles, has to be tailored so that parts of the tissue can assume the function of the chordae tendineae to minimise the closing reflux.

Effect of pleurotomy on blood loss during coronary artery bypass grafting.

Abstract  Background: We conducted a retrospective study to compare two different techniques of internal mammarian artery (IMA) preparation concerning pleurotomy upon the effects of blood loss and pulmonary functions. Methods: Between January 1998 and November 2006, 1357 consecutive patients undergoing coronary artery bypass grafting (CABG) using the left IMA, either alone or in combination with saphenous vein graft, were included in this study. The patients were divided into two groups according to the pleural opening: Group I (n = 1046) patients underwent IMA harvesting with pleurotomy and Group 2 (n = 311) patients with intact pleura. Results: During the study, 27 hospital deaths (1.9%) occurred. The amount of postoperative blood loss and blood transfusion requirements were significantly higher in Group 1 than in Group 2 (p = 0.029 and p = 0.0001). The mechanical ventilation stay was significantly higher in Group 1 than in Group 2 (p = 0.0001). The incidence of left pleural effusion and atelectasis was significantly higher in Group 1 than in Group 2 on day 1 and day 3 after operation. Conclusions: These results demonstrate that preserving pleural integrity has beneficial effects on the postoperative blood loss. Postoperative blood loss and transfusion requirements were higher in patients with pleurotomy. Left pleural effusion, atelectasis, and mechanical ventilatory stay were significantly reduced in patients with preserved pleural integrity.

The role of 99Tcm-tetrofosmin myocardial perfusion scintigraphy in the assessment of patients with previous myocardial infarction: a comparative study with 201Tl.

The aim of this study was to determine the utility of 99Tcm-tetrofosmin cardiac imaging in patients with previous myocardial infarction and with significant coronary artery disease (CAD) compared with that of 201T1 cardiac imaging. Sixteen patients (14 males, 2 females) were studied by same-day exercise-rest 99Tcm-tetrofosmin imaging and exercise, rest and reinjection 201T1 cardiac imaging. For each study, semi-quantitative visual analysis was performed in 20 segments using a 4-point scale. The regional distribution and defect reversibility with the two tracers were compared with the results of coronary angiography. A total of 320 segments were analysed.There was a statistically significant concordance between the numbers of fixed and reversible segments in both studies in myocardial segments supplied by totally occluded coronary arteries (Group 1), as well as in segments supplied by significantly stenosed coronary vessels (Group 2). The exercise and rest uptake of both 99Tcm-tetrofosmin and 201T1 in myocardial segments supplied by totally occluded coronary arteries with poor collateral flow was significantly lower compared with segments supplied by totally occluded coronary arteries with efficient collateral flow (P ≤ 0.05). When the uptake of both tracers was analysed according to each major vascular territory, the mean exercise and rest uptake grades of 99Tcm-tetrofosmin and 201T1 were similar. There was also no significant difference in defect reversibility between the two tracers. Discordant results were observed in the territory of the right coronary artery in Group 1 (mean exercise grade of 99Tcm-tetrofosmin = 2.26 ± 0.7 and of 201T1 = 1.92 ± 0.8; P ≤ 0.001) and in Group 2 (mean grade of 99Tcm-tetrofosmin = 0.79 ± 0.65 and of 201T1 = 0.95 ± 0.65; P ≤ 0.05).The results of the present study indicate that the overall diagnostic utility of 99Tcm-tetrofosmin in the identification of individual stenosed vessels is comparable with 201T1 in both patients with totally occluded coronary arteries and those with significantly stenosed vessels. The regional distribution of both tracers was lower in myocardial segments supplied by totally occluded coronary arteries with poor collateral flow.

Renal failure after coronary bypass surgery and the associated risk factors.

OBJECTIVE We aimed to evaluate the risk factors associated with acute renal failure in patients who underwent coronary artery bypass surgery. METHODS One hundred and six patients who developed renal failure after coronary artery bypass grafting (CABG) constituted the study group (RF group), while 110 patients who did not develop renal failure served as a control group (C group). In addition, the RF group was divided into two subgroups: patients that were treated with conservative methods without the need for hemodialysis (NH group) and patients that required hemodialysis (HR group). Risk factors associated with renal failure were investigated. RESULTS Among the 106 patients that developed renal failure (RF), 80 patients were treated with conservative methods without any need for hemodialysis (NH group); while 26 patients required hemodialysis in the postoperative period (HR group). The multivariate analysis showed that diabetes mellitus and the postoperative use of positive inotropes and adrenaline were significant risk factors associated with development of renal failure. In addition, carotid stenosis and postoperative use of adrenaline were found to be significant risk factors associated with hemodialysis-dependent renal failure (P < .05). The mortality in the RF group was determined as 13.2%, while the mortality rate in patients who did not require hemodialysis and those who required hemodialysis was 6.2% and 34%, respectively. CONCLUSIONS Renal failure requiring hemodialysis after CABG often results in high morbidity and mortality. Factors affecting microcirculation and atherosclerosis, like diabetes mellitus, carotid artery stenosis, and postoperative vasopressor use remain the major risk factors for the development of renal failure.