Suat Büket

Cardiac surgery with cardiopulmonary bypass in patients with chronic renal failure.

OBJECTIVE Renal failure is known to increase the morbidity and mortality in patients undergoing cardiac surgery. The results of heart surgery in patients with non-dialysis-dependent, mild renal insufficiency are not clear. METHODS One hundred nineteen adult patients with chronic renal failure underwent cardiac surgery. Group I consisted of 93 patients who had creatinine levels between 1.6 and 2.5 mg/dL but who were not supported by dialysis. Group II consisted of 18 patients with creatinine levels higher than 2.5 mg/dL who were not supported by dialysis. Group III consisted of 8 patients with end-stage renal disease who were receiving hemodialysis. RESULTS The hospital mortality rates were 11.8%, 33.0%, and 12.5%, respectively. Morbidity was 21.5%, 44.4%, and 75.0%, respectively, in groups I, II, and III. Postoperative hemodialysis was needed in 2 (2.15%) patients from group I and 6 (33%) patients from group II. On multivariable logistic regression analysis, risk factors for mortality were preoperative creatinine level more than 2.5 mg/dL, angina class III-IV, emergency operation, excessive mediastinal hemorrhage, postoperative pulmonary insufficiency, low cardiac output, and rhythm disturbances. Risk factors for morbidity were preoperative creatinine level more than 2.5 mg/dL and postoperative dialysis. CONCLUSIONS Chronic renal failure increases the mortality and morbidity in patients undergoing cardiac surgery. Renal insufficiency with creatinine levels higher than 2.5 mg/dL increases the risk of postoperative dialysis and prolongs the length of hospital stay. Careful preoperative management and intraoperative techniques, such as avoiding low perfusion pressure and using low-dose dopamine, may be useful for a good operative outcome.

Amiodarone reduces the incidence of atrial fibrillation after coronary artery bypass grafting

OBJECTIVE The purpose of this study was to evaluate the safety and efficacy of postoperative administration of prophylactic amiodarone in the prevention of new-onset postoperative atrial fibrillation in patients undergoing coronary artery bypass grafting. METHODS In this prospective study 157 patients were randomly divided into two groups: 77 patients (amiodarone group) received intravenous amiodarone in a dose of 10 mg/kg/d for postoperative 48 hours. On postoperative day 2 oral amiodarone was started with a dose of 600 mg/d for 5 days, 400 mg/d for the following 5 days, and 200 mg/d for 20 days, and 80 patients received placebo (control group). RESULTS Preoperative patient characteristics and operative variables were similar in the two groups. Postoperative atrial fibrillation occurred in 8 patients (10.4%) receiving amiodarone and in 20 (25.0%) patients receiving placebo (P =.017). Duration of atrial fibrillation was 12.8 +/- 4.8 hours for the amiodarone group compared with 34.7 +/- 28.7 hours for the control group (P =.003). The maximum ventricular rate during atrial fibrillation was slower in the amiodarone group than in the control group (105.9 +/- 19.1 beats per minute and 126.0 +/- 18.5 beats per minute, respectively, P =.016). The two groups had a similar incidence of complication other than rhythm disturbances (20.8% vs 20.0%, P =.904). Amiodarone group patients had shorter hospital stays than that of control group patients (6.8 +/- 1.7 days vs 7.8 +/- 2.9 days, P =.014). The in-hospital mortality was not different between two groups (1.3% vs 3.8, P =.620). CONCLUSIONS Postoperative intravenous amiodarone, followed by oral amiodarone, appears to be effective in the prevention of new-onset postoperative atrial fibrillation. It also reduces ventricular rate and duration of atrial fibrillation after coronary artery bypass grafting. It is well tolerated and decreases the length of hospital stay.

Easy Harvesting of Radial Artery With Ultrasonically Activated Scalpel

BACKGROUND The radial artery was proposed and then abandoned as a coronary artery bypass graft in the 1970s. Development of new pharmacologic antispasmodic agents and minimally traumatic harvesting techniques has led to a revival of the use of the radial artery in coronary artery bypass surgery. Usually the main reasons for the spasm are thermal injury caused by electrocautery and traumatic harvesting technique. METHODS In our technique an ultrasonically activated scalpel (Harmonic Scalpel; Ultracision Inc, Smithfield, RI) was used for radial artery harvesting without using hemostatic clips for vessel side branches. The patients in the study were divided into two groups of 10 patients each. In the first group radial arteries were harvested with this technique, and in the second group with hemostatic clips, scissors, and minimal electrocautery. Harvesting time, frequency of spasm, and use of hemostatic clips were compared between the two groups. RESULTS The Harmonic Scalpel decreased the harvesting time, frequency of spasm, and excessive use of hemostatic clips. CONCLUSIONS Good coagulation capacity with markedly decreased use of hemostatic clips and minimized thermal injury offers the surgeon the ability to perform less traumatic, spasm free, and rapid radial artery harvesting.

Perioperative Risk Factors for Mortality in Patients With Acute Type A Aortic Dissection

BACKGROUND This study was undertaken to identify the perioperative risk factors for death in patients with acute type A aortic dissection (AADA). METHODS Between 1993 and 2001, 108 consecutive patients (86 men; mean age, 53 years) underwent emergent operations for AADA. All patients but 2 underwent replacement of the ascending aorta with an open distal anastomosis during a period of hypothermic circulatory arrest. In addition, 22 patients had hemiarch and 5 had total arch replacement. Aortic root was replaced in 20 and repaired with gelatin-resorcinol-formaldehyde glue in 39 patients; aortic valve was separately replaced in 3, resuspended in 24, and remained untouched in 22 patients. RESULTS Overall in-hospital mortality was 25%. Mortality rate was significantly higher in patients with preoperative dissection complications than in those without (21/36 [58%] vs 6/72 [8%], p < 0.001). In multivariate analysis, predictors of mortality were presence of rupture, renal failure, and intestinal malperfusion, duration of cardiopulmonary bypass > or = 200 minutes, blood loss > or = 500 mL, and transfusion of blood > or = 4 units. Location of the intimal tear, extent of the replacement, type of the aortic root repair, and duration of hypothermic circulatory arrest did not emerge as predictors of mortality. CONCLUSIONS Major determinants of surgical mortality in patients with AADA are preoperative complications. Earlier diagnosis remains essential to improve the survival rate.

Importance of early dialysis for acute renal failure after an open-heart surgery.

Coronary artery disease is a major cause of death in patients with a renal dysfunction. Among the patients who undergo coronary artery bypass grafting, renal dysfunction is known to be a major predictor of in‐hospital and out‐of‐hospital mortality. From 2004 to 2007, we performed elective open‐heart surgeries on 2380 patients in whom there was no primary renal failure. Of those patients, only 185 in whom acute renal failure (ARF) was developed were included in the study. The patients were divided into 2 groups: a late dialysis group (n=90) and an early dialysis group (n=95). The mean age of the patients was 62.3±6.4 in the late dialysis group and 64.5±5.2 in the early dialysis group. There were 32 female and 58 male patients in the late dialysis group and 36 female and 59 male patients in the early dialysis group. Acute renal failure developed only in 185 patients out of 2380 open‐heart surgery patients. The overall mortality in the 2380 open‐heart surgery patients was 1.97%. Mortality among the ARF patients was 5.9%. However, there was no significant difference in hospital mortality between the 2 groups. Major complications, such as postoperative pneumonia, prolonged ventilation time, arrhythmia, the number of times postoperative hemodialysis was performed, development of chronic renal failure, time spent in the intensive care unit and the period of hospitalization, sepsis, and low cardiac output, were significantly higher in the late dialysis group. There was no difference in mortality between the 2 groups. Early dialysis for open‐heart surgery patients who develop ARF postoperatively does not decrease mortality. However, it decreases morbidity, the amount of time spent in intensive care, and the period of hospitalization and thus reduces patient costs.

The effects of modified hemofiltration on inflammatory mediators and cardiac performance in coronary artery bypass grafting

Cardiopulmonary bypass increases the blood levels of various immune mediators, thereby leading to a systemic inflammatory response syndrome, e.g. sepsis, with some hemodynamic alterations, such as vasodilatation, tachycardia, and a decrease in systemic vascular resistance. Perioperative hemofiltration is one of the treatment modalities proposed to prevent this syndrome. Modified hemofiltration has been introduced recently by investigators who recommend that the former standard techniques are ineffective in eliminating the inflammatory mediators. The purpose of this study was to determine the effects of the modified technique on these mediators and on hemodynamic parameters. Forty patients undergoing coronary artery bypass grafting were randomized into equal control and hemofiltered groups. The hemodynamic parameters, as well as blood samples, were taken before and after hemofiltration to assess blood concentrations of interleukin-6, interleukin-8 and neopterin. The hemodynamic parameters and immune mediator levels did not differ between the two groups during the course of the study, except in the immediate postoperative periods, where cardiac output, cardiac index, and systemic vascular resistance values were significantly greater in the hemofiltered group while there were no differences in the immune mediators. The results of our study suggest that the effects of modified hemofiltration on immune mediators are still debatable. The improvement found in cardiac performance could be attributed to the prevention of hemodilution and hypervolemia.

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.

Intermittent infusion of 0.25% bupivacaine through an intrapleural catheter for post-thoracotomy pain relief

BACKGROUND The present study was designed to evaluate the effectiveness of intrapleural 0.25% bupivacaine delivered by intermittent infusions for post-thoracotomy pain relief. METHODS Forty patients undergoing elective lobectomy were randomly, but equally, placed into two groups. An intrapleural catheter was inserted under direct vision during surgery. Group I received intrapleural 40 mL of 0.25% bupivacaine, group II was administered 40 mL of saline solution as a control group. Diclofenac sodium was administered as an additional analgesic, if required. Postoperative pain was evaluated using a visual analog scale (VAS), and Prince Henry pain scale. Arterial oxygen saturation, heart rate, and systemic arterial pressures were monitored. All observations were recorded 5, 10, 15, 20, 25, and 30 minutes after the injection, and thereafter at hourly intervals through the postoperative 24 hours. RESULTS The mean analgesia times were 5 hours and 2 hours in group I and group II, respectively. Therefore, bupivacaine administrations were repeated every 6 hours in group I, and saline with additional analgesic were administered every 4 hours in group II. The heart rate and arterial pressures did not show a significant difference. While the additional analgesic requirement was 180 +/- 10 mg/d in group II, there was no need for additional analgesic administration in the group I patients. Arterial oxygen was significantly higher in group I than in group II. Arterial carbon dioxide tension of group II was significantly higher than that of group I. While the postoperative atelectasis and pneumonia developed in four patients and one, respectively, in group II, no such complication was observed in group I. CONCLUSIONS The easy placement of an intrapleural catheter and better pain relief observed in the present study suggest that intermittent pleural infusion of 0.25% bupivacaine has proven to be a safe and effective method for relief of post-thoracotomy pain.

Effects of flow types in cardiopulmonary bypass on gastric intramucosal pH

The aim of this study was to determine the relationship between splanchnic perfusion and oxygen consumption, and flow types in cardiopulmonary bypass (CPB), by measuring gastric intramucosal pH. Twenty patients undergoing elective open-heart surgery were prospectively randomized to receive either pulsatile or nonpulsatile flow during CPB. Gastric intramucosal pH was measured using gastric tonometry. A flowmeter was used to measure the inferior caval vein flow. A catheter was inserted through the femoral vein to sample blood from the iliac vein. Systemic vascular resistance index, gastric intramucosal pH, inferior caval vein flow and arterial, inferior vena caval and iliac venous blood gases were recorded at different times. Gastric intramucosal pH decreased in all patients; only in the nonpulsatile group was this decrease statistically significant. After 45 min of CPB, the pH was 7.37 ± 0.03 compared with the prebypass value of 7.48 ± 0.04 (p = 0.00016). After weaning from CPB, the pH was 7.358 ± 0.02 compared with the prebypass value (p = 0.000037). At 2 h post-operatively the pH was 7.416 ± 0.025 (p = 0.02). Systemic vascular resistance index rose in all patients during bypass in both groups. These changes did not have any statistical significances and after weaning from bypass returned to prebypass levels. We conclude that nonpulsatile flow in CPB is associated with reduced gastric intramucosal pH and the measurement of intramucosal pH during open-heart surgery provides important information about splanchnic perfusion.

Determinants of Early Mortality and Neurological Morbidity in Aortic Operations Performed Under Circulatory Arrest

Abstract Objective: Aneurysms and dissections of the thoracic aorta continue to present a surgical challenge and their incidence is increasing in recent years. The mortality rate of surgical treatment is still higher than those of other cardiovascular operations. Neurological injury is the most feared complication resulting from repair of these lesions. This study aims to determine the factors that influence the neurological outcome and mortality after thoracic aortic operations. Methods: During the period from November 1993 through May 1999, 144 patients were operated on for conditions involving the ascending aorta and/or aortic arch. Ninety‐five (66.0%) were operated for aortic dissection and 49 (34.0%) were for aortic aneurysms. Sixty‐two patients (43.1%) had replacement of ascending aorta with distal open technique; 82 patients (56.9%) had hemiarch or total arch replacement or repair of the distal arch. Results: Twenty‐seven (18.7%) early deaths occurred. New stroke occurred in two patients (1.4%) and temporary neurological dysfunction in nine patients (6.3%). Deep hypothermic circulatory arrest with retrograde cerebral perfusion was used in all patients. On multivariate logistic regression analysis, risk factors for mortality were chronic renal failure, preoperative organ malperfusion, rupture, total circulatory arrest time > 60 minutes, postoperative acute renal failure, postoperative low cardiac output, sepsis, and multiple organ failure. Risk factors for neurological morbidity were preoperative chronic renal failure, preoperative hemodynamic instability, postoperative low cardiac output, and pulmonary complications. Conclusions: Hypothermic circulatory arrest with retrograde cerebral perfusion was not an independent predictor of neurological morbidity on multivariate analysis, even if the arrest period was more than 60 minutes. Lengths of circulatory arrest periods and clinical presentations of the patients are important determinants of mortality.