Short- and long-term prognostic value of postoperative cardiac troponin I concentration in patients undergoing coronary artery bypass grafting

BACKGROUND: The value of postoperative cardiac troponin I (cTnI) has been shown to indicate a higher risk of in-hospital death after cardiac surgery. The authors therefore assessed the long-term prognostic value of cTnI in patients undergoing elective coronary artery bypass grafting. METHODS: Consecutive patients (n = 202) were included and divided into two groups according to the postoperative value of cTnI (< or >/= 13 ng/ml). In-hospital mortality and nonfatal cardiac events (delayed extubation > 24 h; postoperative requirement of inotropic agent; ventricular and supraventricular arrhythmia; postoperative myocardial infarction) were recorded. Survivors were then followed up over a 2-yr period. Data are median and odds ratio (95% confidence interval). RESULTS: Of all patients, 174 (86%) had a low cTnI (4.1 ng/ml; range, 1.1-12.6) and 28 (14%) had a high cTnI (23.8 ng/ml; range, 13.4-174.6). In-hospital mortality was not significantly different (4 vs. 2%), whereas long-term mortality (18 vs. 3%, P = 0.006) and mortality from cardiac cause (18 vs. 1%, P < 0.001) was greater in patients with a high cTnI. A high cTnI was a significant factor predicting death (odds ratio, 7.3 [2.0-27.1]) or death from cardiac causes (odds ratio, 37.4 [4.2-334.4]). Nonfatal cardiac events were also more frequent in the hospital (64 vs. 41%, P = 0.02) and within the 2-yr follow-up period (39% vs. 16%, P = 0.03) in patients with high cTnI. CONCLUSION: A high postoperative peak of cTnI is associated with increased risk of death, death from cardiac causes, and nonfatal cardiac events within 2 yr after coronary artery bypass grafting.     

Isoflurane, 0.5 minimum alveolar concentration administered through the precardiopulmonary bypass period, reduces postoperative dobutamine requirements of cardiac surgery patients: a randomized study

OBJECTIVE: Cardioprotective properties have been shown with halogenated volatile agents. It was hypothesized that low-dose isoflurane administered before aortic cross-clamping may reduce the amount of dobutamine required to improve impaired postoperative cardiac function after various types of cardiac surgery. DESIGN: A prospective, randomized trial. SETTING: An anesthesia and intensive care unit, university hospital. PARTICIPANTS: Two hundred eighty cardiac surgery patients. INTERVENTIONS: All patients allocated to either isoflurane treatment (T) or no treatment (control group [C]) received total intravenous anesthesia. In the treatment group, isoflurane was administered at a 0.5 minimum alveolar concentration (MAC) from tracheal intubation to initiation of cardiopulmonary bypass (CPB). During weaning from CPB, dobutamine was introduced by using a hemodynamically driven decision tree. MEASUREMENTS AND MAIN RESULTS: The number of patients receiving dobutamine was comparable (66 v 78, p = 0.07, in T and C groups, respectively). The total amount of postoperative dobutamine indexed to patient weight, considered as the primary endpoint, was reduced in the isoflurane-treated group (4.2 +/- 8 v 7.2 +/- 15, p < 0.02, in T and C, respectively). Isoflurane was identified as an independent variable significantly (odds ratio [confidence interval]) influencing the total amount of postoperative dobutamine (0.53 [0.31-0.92], p < 0.02). Postoperative troponin I release at 20 hours was not affected by isoflurane treatment. CONCLUSIONS: This study revealed that exposure to 0.5 MAC isoflurane before CPB reduced the total amount of dobutamine required to normalize postoperative cardiac dysfunction in various types of cardiac surgical patients.     

Short- and Long-term Prognostic Value of Postoperative Cardiac Troponin I Concentration in Patients Undergoing Coronary Artery Bypass Grafting

Background: The value of postoperative cardiac troponin I (cTnI) has been shown to indicate a higher risk of in-hospital death after cardiac surgery. The authors therefore assessed the long-term prognostic value of cTnI in patients undergoing elective coronary artery bypass grafting.

Methods: Consecutive patients (n = 202) were included and divided into two groups according to the postoperative value of cTnI (< or >= 13 ng/ml). In-hospital mortality and nonfatal cardiac events (delayed extubation > 24 h; postoperative requirement of inotropic agent; ventricular and supraventricular arrhythmia; postoperative myocardial infarction) were recorded. Survivors were then followed up over a 2-yr period. Data are median and odds ratio (95% confidence interval).

Results: Of all patients, 174 (86%) had a low cTnI (4.1 ng/ml; range, 1.1-12.6) and 28 (14%) had a high cTnI (23.8 ng/ml; range, 13.4-174.6). In-hospital mortality was not significantly different (4 vs. 2%), whereas long-term mortality (18 vs. 3%, P = 0.006) and mortality from cardiac cause (18 vs. 1%, P < 0.001) was greater in patients with a high cTnI. A high cTnI was a significant factor predicting death (odds ratio, 7.3 [2.0-27.1]) or death from cardiac causes (odds ratio, 37.4 [4.2-334.4]). Nonfatal cardiac events were also more frequent in the hospital (64 vs. 41%, P = 0.02) and within the 2-yr follow-up period (39%vs. 16%, P = 0.03) in patients with high cTnI.     

Risk stratification with cardiac troponin I in patients undergoing elective coronary artery bypass surgery.

OBJECTIVE: Cardiac troponin I (cTnI) is a highly sensitive and specific marker for postoperative prediction of patients outcome after coronary artery bypass surgery (CABG). Whether preoperatively elevated cTnI levels similarly predict the outcome in patients scheduled for elective CABG is currently unknown. METHODS: Therefore, a possible correlation between preoperative cTnI levels and perioperative major adverse events and in-hospital mortality after CABG was investigated. CTnI was measured within 24h before surgery in 1405 out of 3124 consecutive elective CABG patients. Out of these patients, 1178 had a preoperative cTnI level below 0.1ng/ml (group 1), 163 patients had a cTnI level between 0.11 and 1.5ng/ml (group 2), and 64 patients had a cTnI level above 1.5ng/ml (group 3). CTnI levels, electrocardiograms, clinical data, adverse events and in-hospital mortality were recorded prospectively. Patients with ST-elevation myocardial infarction less than 7 days before surgery were excluded from the study. RESULTS: Perioperative myocardial infarction (PMI) occurred in 69/1178 patients (5.9%) in group 1, 14/163 patients (8.6%; odds ratio (OR) 1.5, 95% confidence interval (CI): 0.8-2.8) in group 2, and 11/64 patients (17.2%; OR 3.3, CI: 1.6-7.0) in group 3 (overall: P<0.001, Cochran-Armitage trend test). Low cardiac output syndrome (LCOS) occurred in 19/1178 patients (1.6%), 9/163 (5.5%; OR 3.6, CI: 1.5-8.5), and 7/64 patients (10.9%; OR 7.5, CI: 2.7-19.8) (overall: P<0.001, group 1 vs. group 2: P<0.002), respectively. In-hospital mortality was 1.7% in group 1 and 3.1% in group 2, but 6.3% (OR 3.9, CI: 1.1-12.5) in group 3 (overall: P<0.01, group 1 vs. group 2: P=NS). Intensive care and hospital stay were significantly longer in group 3 compared to groups 1 and 2. Univariate and multivariate logistic regression analysis confirmed the statistically significant relationship between cTnI and PMI, LCOS and in-hospital mortality, respectively (P<0.001). CONCLUSIONS: Risk stratification by measurement of cTnI levels within 24h before elective CABG clearly identifies a subgroup of patients with increased risk for postoperative adverse outcome and in-hospital mortality.     

冠状动脉旁路移植术围术期心肌肌钙蛋白I动态变化

目的　观察心肌肌钙蛋白I(cTnI)和CK -MB在冠状动脉旁路移植术 (CABG)围术期变化 ,以判断心肌损伤状况。方法　 19例CABG病人 ,其中 3例同时行左室室壁瘤切除。平均体外循环时间12 1min ,阻断升主动脉 5 6min。灌注冷血停跳液保护心肌 ,平均每例搭桥 3 2支。围术期 2 0个时间点取静脉血标本 ,留血浆测cTnI和CK MB。术前及术后第 7d作标准 12导联心电图 (ECG)。结果　cTnI术前 5例升高者 ,停机后全部升高 ,第 8h达高峰 ,术后第 7d有 7例 (36 8% )仍高于正常 ;CK MB阻断升主动脉前正常 ,停机后升高 ,第 6h达高峰 ,术后第 2d全部恢复正常 ;2例发生围术期心梗 (PMI)者 ,整个围术期cTnI高于无PMI者 ;cTnI阻断升主动脉前已升高者 ,术后升高更显著。结论　cTnI与CK MB在CABG术后变化规律相似 ,但cTnI高于正常的持续时间长于CK MB ,有利于回顾性诊断 ;若阻断升主动脉前cTnI已升高 ,术后水平更高 ;cTnI诊断心肌损伤敏感性高于CK -MB。     

Atrial fibrillation and plasma troponin I elevation after cardiac surgery: relation to inflammation-associated parameters

BACKGROUND: Recent studies have demonstrated correlation between inflammation to plasma troponin (cTnI) levels elevation and atrial fibrillation (AF) in noncardiac surgery settings. The goal of this prospective study was to examine the relation between inflammation associated parameters (IAPs) to post cardiac surgery cTnI elevation and AF. METHODS: A single post CABG cTnI measurement was assessed in 156 consecutive patients. Clinical, operative and postoperative data, IAPs (hypophosphatemia, preoperative statin treatment, immediate postoperative fever, and prolonged mechanical ventilation) and in-hospital AF episodes were prospectively recorded. RESULTS: Mean cTnI level was 14.4 +/- 12.4 ng/mL. In the two in-hospital deaths (1.2%) cTnI concentration was less than 12 ng/mL. Cardiac troponin-I levels were significantly higher in patients not preoperatively treated with statins (21.6 +/- 4.1 vs. 13.3 +/- 0.9, p = 0.05), in patients who needed intraoperative cardioversion (16.7 +/- 2.2 vs. 12.2 +/- 0.9, p = 0.07), in patients with postoperative hypophosphatemia (16.9 +/- 10.0 vs. 11.1 +/- 13.7, p = 0.04), postoperative fever (18.6 +/- 3.0 vs. 13.7 +/- 1.0, p = 0.07) and postoperative respiratory complications (23.9 +/- 4.3 vs. 13.5 +/- 1.0, p = 0.04). Step-wise logistic regression analysis revealed the following parameters as independently associated with elevated cTnI levels: preoperative statin treatment (CI 95%-15.9; -1.7, p = 0.02), intraoperative ventricular arrhythmia (CI 95%-0.7; 13.8, p = 0.08), hypophosphatemia (CI 95% 0.9; 8.6, p = 0.02), postoperative fever (CI 95% 0.9; 11.0, p = 0.02), and postoperative respiratory complications (CI 95% 0.1; 0.5, p = 0.01). Of the 156 patients, 50 (32.1%) had postoperative AF. The first episode of AF occurred between postoperative day 1 and 6 (mean-day 2). Mean duration of AF was 21.8 +/- 8.1 hours. Postoperative AF was significantly associated with age above 75 (50% vs. 29.4%, p = 0.01), hypertension (37% vs. 18%, p = 0.02), preoperative calcium channel blockers treatment (44% vs. 26%, p = 0.02), furosemide treatment (58% vs. 30%, p = 0.05), and preoperative left atrial diameter above 40 mm (56% vs. 29%, p = 0.01). Postoperatively, AF was significantly associated with postoperative renal failure (70% vs. 29%, p = 0.01), respiratory complications (61% vs. 29%, p = 0.02), and prolonged hospital stay (OR 1.1; CI 1.0-1.3; p < 0.05). No association was found between troponin levels and postoperative AF. Multivariable analysis found only left atrial enlargement and prolonged hospital stay independently associated with AF. CONCLUSIONS: A significant correlation between clinical IAPs and cTnI plasma level elevation was found after cardiac surgery. There was no correlation between these parameters and postoperative AF, and there was no correlation between postoperative plasma cTnI levels and the occurrence of AF. Preoperative treatment with statins may be beneficial in reducing postoperative inflammatory response but further study has to be carried out.     

Comparison of propofol and isoflurane anesthesia in orthotopic pig-to-baboon cardiac xenotransplantation

BACKGROUND: Orthotopic pig-to-baboon xenogeneic heart transplantation (oXHTx) is the only accepted preclinical animal model for cardiac xenotransplantation. We compared the hemodynamic stability of a propofol- and isoflurane-based anesthetic regimen during oXHTx. METHODS: Hearts from 12 hDAF or hCD46 transgenic pigs (Sus scrofa; body weight 7 to 32 kg) were transplanted into baboons (Papio anubis and Papio hamadryas; body weight 9 to 26 kg) in the orthotopic life-supporting position. Animals received a propofol-based intravenous regimen or inhalation anesthesia with isoflurane. Analgesia was achieved with fentanyl in both groups. Systemic hemodynamic variables were measured before, during and after cardiopulmonary bypass (CPB) and the need for inotropic or vasoactive pharmacological support was compared before and after CPB. RESULTS: Global hemodynamic variables [i.e. heart rate, mean arterial pressure (MAP) and cardiac output] were not significantly different in propofol-anesthetized baboons compared to baboons anesthetized with isoflurane. Baboons anesthetized with isoflurane showed a trend towards less pharmacological support required to achieve an adequate MAP of >60 mmHg after CPB (propofol: epinephrine 0.13 [0.05; 0.16] and norepinephrine 0.15 [0.02; 0.16] microg/kg/min vs. isoflurane: epinephrine 0.05 [0.02; 0.08] and norepinephrine 0.06 [0.02; 0.19] microg/kg/min; no significant difference). CONCLUSIONS: Propofol and isoflurane appear to provide equal hemodynamic stability in orthotopic cardiac pig-to-baboon xenotransplantation prior to the start of CPB. The trend of a reduced catecholamine support needed after CPB, however, suggests that isoflurane may be the preferred drug for maintenance of anesthesia in this primate model.     

Hypomagnesemia is common following cardiac surgery

Hypomagnesemia is a common disorder in noncardiac surgical patients in the postoperative period, but the effect of cardiac surgery on serum magnesium concentrations remains unclear. The authors hypothesized that cardiac surgery is associated with hypomagnesemia, and prospectively studied 101 subjects (60 +/- 13.1 years of age) undergoing coronary artery revascularization (n = 70), valve replacement (n = 24), or both simultaneously (n = 7). Blood samples and clinical biochemical data were collected before induction of anesthesia, prior to cardiopulmonary bypass (CPB), immediately after CPB, and on postoperative day 1. Blood samples were analyzed for ultrafilterable magnesium, total magnesium, ionized calcium, parathyroid hormone, and free fatty acid concentrations. Outcome variables were also determined. Eighteen of 99 (18.2%) subjects had hypomagnesemia preinduction and this number increased to 71 of 100 (71.0%) following cessation of CPB (P less than 0.05). Patients with postoperative hypomagnesemia had a higher frequency of atrial dysrhythmias (22 of 71 [31.0%] v 3 of 29 [10.3%], P less than 0.05) and required prolonged mechanical ventilatory support (22 of 63 [34.9%] v 4 of 33 [12.1%], P less than 0.05). Hypomagnesemia is common following cardiac surgical procedures with CPB and is associated with clinically important postoperative morbidity.     

Aprotinin and renal dysfunction after pediatric cardiac surgery

BACKGROUND: Aprotinin is a potent antifibrinolytic drug, which reduces postoperative bleeding and transfusion requirements. Recently, two observational studies reported increased incidence of renal dysfunction after aprotinin use in adults. Therefore, the aim of the study was to investigate the safety of aprotinin use in pediatric cardiac surgery patients. METHODS: Data were prospectively and consecutively collected from 657 pediatric patients undergoing cardiac surgery with cardiopulmonary bypass (CPB). The database was assessed with regard to a possible relationship between aprotinin administration and dialysis and between aprotinin and postoperative renal dysfunction [defined as 25% decrease in the creatinine clearance (Ccr) compared with the preoperative value] by propensity-score adjustment and multivariable methods. RESULTS: The incidence of dialysis (9.6% vs 4.1%; P = 0.005) and renal dysfunction (26.3% vs 16.1%; P = 0.019) was higher in patients who received aprotinin; however, propensity adjusted risk ratios were not significant [odds ratio (OR) of dialysis: 1.22; 95% confidence interval (CI) 0.46-3.22; OR of renal dysfunction 1.26; 95% CI: 0.66-1.92]. Aprotinin significantly reduced blood loss in the first postoperative 24 h. The main contributors of renal dysfunction were CPB duration, cumulative inotropic support, age, preoperative Ccr, amount of transfusion and pulmonary hypertension. CONCLUSIONS: Despite the higher incidences of renal dysfunction and failure in the aprotinin group, an independent role of the drug in the development of renal dysfunction or dialysis could not be demonstrated in pediatric cardiac patients undergoing CPB.     

High-dose aprotinin reduces activation of hemostasis,allogeneic blood requirement,and duration of postoperative ventilation in pediatric cardiac surgery

BACKGROUND: Though multiple studies have affirmed the effectiveness of aprotinin in reducing blood loss in adult cardiac surgery, the possible benefit in pediatric cardiac surgery is controversial. METHODS: In a double-blind, randomized, and placebo-controlled study, the efficacy of aprotinin in attenuating the hemostatic and inflammatory activation during cardiopulmonary bypass in 60 patients weighing less than 10 kg was investigated. Secondary endpoints were the influence of aprotinin on the reduction of blood loss and allogeneic blood requirement, as well as postoperative oxygenation and length of mechanical ventilation. Aprotinin was administered in a high-dose of 3 x 10(4) KIU/kg plus a bolus of 5 x 10(5) KIU (not weight adjusted) added to the pump prime. RESULTS: Aprotinin plasma concentration at the end of cardiopulmonary bypass (CPB) was with 184 +/- 45 KIU/mL, within the targeted range of 200 KIU/mL. Coagulation and fibrinolysis were suppressed (F1.2 1 hour after CPB: 5.35 +/- 2.9 nmol/L vs 14.5 +/- 23.1 nmol/L; D-dimer 1 hour after CPB: 0.63 +/- 0.6 ng/mL vs 2.3 +/- 3.1 ng/mL; p < 0.05), inflammatory markers (interleukin [IL]-6, IL-8, IL-10) increased over time without significant differences between the groups, and only complement C3a activation was significantly attenuated at the end of CPB in the aprotinin group. Chest tube drainage was significantly reduced (24 hours: median 13.5 [IQR 12.2] mL/kg vs 19.4 [8.2] mL/kg; p < 0.05). All patients received one unit of packed cells to prime the heart lung machine. A second unit was needed significantly less often in the aprotinin group (13% vs 47%; p < 0.05). Postoperative oxygenation (pO2/FIO2 172 [IQR 128] mm Hg vs 127 [74]; p < 0.05) improved, and the time on ventilator was shorter in the aprotinin group (median 45 hours [IQR 94] vs 101 [IQR 74]; p < 0.05). No side effects were attributable to the use of aprotinin. CONCLUSIONS: High-dose aprotinin effectively attenuated hemostatic activation and reduced blood loss and transfusion requirement in pediatric cardiac surgery. Postoperative ventilation was also shortened in the aprotinin group.     

Minimal versus conventional cardiopulmonary bypass: assessment of intraoperative myocardial damage in coronary bypass surgery.

OBJECTIVE: Minimal extracorporeal circulation (mini-ECC) is a new technology, consisting of a centrifugal pump, an oxygenator, and a modified suction system. The main advantage of mini-ECC is the reduction of tubing length (reduction of the priming volume). Additional beneficial effects are a decrease of coagulation cascade and a reduction of blood transfusion in patients undergoing coronary artery bypass grafting (CABG) surgery. We compared the intraoperative and early postoperative myocardial damage and outcome of patients who underwent CABG surgery with conventional cardiopulmonary bypass (CPB) or mini-ECC. METHODS: One hundred and thirty-six consecutive patients who underwent isolated CABG surgery at our institution were prospectively studied. Fifty-four patients (39.7%) were operated with mini-ECC. Patient characteristics were similar in both groups. The most interesting intraoperative details as well as in-hospital outcome were assessed. RESULTS: There was no difference in mortality between the two groups. Cross-clamping time was similar in both groups (p = 0.07). Defibrillation was required in one patient in the mini-ECC group (1.9%) and in 38 patients (46.3%) in the CPB group (p < 0.001). In the mini-ECC group, the requirement of inotropic support and incidence of atrial fibrillation was significantly lower than in the CPB group. Postoperative creatine kinase isoenzyme MB (CK-MB) and cardiac Troponin I (cTnI) were significantly lower in the mini-ECC group (p < 0.05). Duration of ventilation, length of stay in the intensive care unit and total hospitalization time were significantly shorter in patients operated with mini-ECC (p < 0.05). CONCLUSION: Mini-ECC is a safe procedure and is followed by a diminished release of CK-MB and cTnI than after CPB. Postoperative recovery is accelerated following mini-ECC and there is a significantly lower incidence of postoperative atrial fibrillation.     

Predictive value of perioperative cardiac troponin I for adverse outcome in coronary artery bypass surgery.

OBJECTIVES: Cardiac Troponin I (cTnI) is a well-known marker for myocardial damage in patients undergoing aorto-coronary bypass grafting (CABG) peaking 6-8 h after aortic declamping. The aim of this study was to evaluate cTnI release in the course of CABG procedures early, i.e. after the cessation of cardiopulmonary bypass (CPB) in order to recognize unstable cardiac function leading to hemodynamic deterioration and resulting in an adverse outcome (AO). AO is defined as the onset of myocardial infarction and/or death peri/postoperatively. METHODS: Five-hundred and forty consecutive patients who underwent CABG were evaluated for cTnI release immediately prior to the induction of anesthesia (IND) and after termination of CPB (END). Standard CPB with ante/retrograde cold blood cardioplegia was used. Patients with any of the following criteria were excluded: (1), CABG within 7 days of myocardial infarction; (2), emergency operation for both unstable angina and for coronary occlusion at angioplasty; (3), CABG with concomitant surgical cardiac procedures; (4), preoperative renal dysfunction requiring hemodialysis; (5), redos. Troponin I was measured with the Stratus CS fluorometric enzyme immunoassay analyzer (Dade-Behring) running on site in the operation room (OR), so values of cTnI could be obtained within 15 min. RESULTS: There were six deaths (1.1%) in the entire series, Q-wave myocardial infarction occurred in 19 patients (3.5%), AO was experienced by 21 patients (3.9%). The mean preoperative cTnI level was 0.04+/-0.17 ng/l (mean+/-standard deviation) for the entire group. The END cTnI level for the AO-group was 0.91+/-0.5 ng/l; for all other patients, this was 0.37+/-0.3 ng/l (P<0.001). Changes in intraoperative cTnI levels relative to time course showed a marked increase for the AO-group (0.0038+/-0.0035 ng/l*min) as compared with non-AO patients (0.0019+/-0.0015 ng/l*min; P=0.028). The receiver operating characteristic curve indicates a cTnI level at CPB-end of higher than 0.495 ng/l with an area under the curve of 0.83 as the optimal cut-off point for predicting AO with a sensitivity and specificity of 76.2%. Stepwise logistic regression analysis revealed END cTnI level (odds ratio, 17.24; P<0.001), CPB time (odds ratio, 1.03; P=0.001), female sex (odds ratio, 3.8; P=0.011) as significant independent predictors for AO. Age of over 70 years (P=0.8), Cleveland Clinic risk score (P=0.65), diabetes (P=0.26), elevated preoperative creatinine level (P=0.77), severe left ventricular dysfunction (P=0.51), the number of grafts performed (P=0.15), and change of intraoperative cTnI level relative to time course (P=0.94) did not reach statistical significance. CONCLUSIONS: cTnI release as determined at the end of CABG procedures represents a strong predictor of an AO after surgery. Analyzing blood samples for cTnI with an automated device on site in the OR provides for immediate results, so specific diagnostic and therapeutic interventions can be performed before hemodynamics deteriorate.     

Renal dysfunction after cardiac surgery with normothermic cardiopulmonary bypass: incidence,risk factors,and effect on clinical outcome

Renal dysfunction is a frequent and severe complication after conventional hypothermic cardiac surgery. Little is known about this complication when cardiopulmonary bypass (CPB) is performed under normothermic conditions (e.g., more than 36 degrees C). Thus, we prospectively studied 649 consecutive patients undergoing coronary artery bypass surgery or valve surgery with normothermic CPB. The association between renal dysfunction (defined as a > or =30% preoperative-to-maximum postoperative increase in serum creatinine level) and perioperative variables was studied by univariate and multivariate analysis. Renal dysfunction occurred in 17% of the patients. Twenty-one (3.2%) patients required dialysis. Independent preoperative predictors of this complication were: advanced age, ASA class >3, active infective endocarditis, radiocontrast agent administration <48 h before surgery, and combined surgery. When all the variables were entered, active infective endocarditis, radiocontrast agent administration, postoperative low cardiac output, and postoperative bleeding were independently associated with renal dysfunction. The in-hospital mortality rate was 27.5% when this complication occurred (versus 1.6%; P < 0.0001). Furthermore, postoperative renal dysfunction was independently associated with in-hospital mortality (odds ratio, 4.1 [95% confidence interval, 1.3-12.8]). We conclude that advanced age, active endocarditis, and recent (within 48 h) radiocontrast agent administration, as well as postoperative hemodynamic dysfunction, are more consistently predictive of postoperative renal dysfunction than CPB factors. IMPLICATIONS: We found that postoperative renal dysfunction was a frequent and severe complication after normothermic cardiac surgery, independently associated with poor outcome. Independent predictors of this complication were advanced age, active endocarditis, and recent (within 48 h) radiocontrast agent administration (the only preoperative modifiable factor), as well as postoperative hemodynamic dysfunction.     

Changes in respiratory mechanics during cardiac surgery

We investigated the role of cardiopulmonary bypass (CPB) in compromised lung function associated with cardiac surgery. Low-frequency respiratory impedance (Zrs) was measured in patients undergoing cardiac surgery with (n = 30; CPB group) or without (n = 29; off-pump coronary artery bypass [OPCAB] group) CPB. Another group of CPB patients received dopamine (DA) (n = 12; CPB-DA group). Extravascular lung water was determined in five CPB subjects. Zrs was measured before skin incision and after chest closure. Airway resistance and inertance and tissue damping and elastance were determined from Zrs data. Airway resistance increased in the CPB group (74.9% +/- 20.8%; P < 0.05), whereas it did not change in the OPCAB group (11.8% +/- 7.9%; not significant) and even decreased in the CPB-DA patients (-40.6% +/- 9.2%; P < 0.05). Tissue damping increased in the CPB and OPCAB groups, whereas it remained constant in the CPB-DA patients. Significant increases in elastance were observed in all groups. There was no difference in extravascular lung water before and after CPB, suggesting that edema did not develop. These results indicate a significant and heterogeneous airway narrowing during CPB, which was counteracted by the administration of DA. The mild deterioration in tissue mechanics, reflecting partial closure of the airways, may be a consequence of the anesthesia itself. IMPLICATIONS: We observed that cardiopulmonary bypass deteriorates lung function by inducing a heterogeneous airway constriction, whereas no such effects were observed in patients undergoing cardiac surgery without bypass. The impairment in parenchymal mechanics, which was obtained in both groups, may result from peripheral airway closure and/or be a consequence of mediator release.     

Cardiac troponin I is an independent predictor of in-hospital death after adult cardiac surgery

BACKGROUND: Although myocardial injury during cardiac surgery is associated with impaired clinical outcome, little is known about the prognostic value of cardiac troponin I (cTnI), a cardiac-specific biologic marker. The purpose of this prospective study was to evaluate the prognostic value of cTnI concentrations measured 20 h after the end of surgery in adult patients undergoing coronary artery bypass grafting or conventional valve surgery. METHODS: Baseline and perioperative characteristics of 502 consecutive patients undergoing conventional heart surgery during a 1-yr period were collected. In-hospital death (n = 28) and major clinical outcomes, e.g., low cardiac output, ventricular arrhythmia, and renal failure, were recorded. RESULTS: Multivariate analysis, using a stepwise logistic regression, showed that cTnI concentration was an independent predictor of in-hospital mortality (for cTnI concentration > 13 ng/ml, odds ratio = 6.7 [95% confidence interval, 2.3-19.3]), as were diabetes, altered preoperative cardiac function, emergent surgery, cardiopulmonary bypass duration, postoperative Pao2 level and total chest drainage volume. Further, elevated cTnI concentrations were associated with a cardiac cause of death and with major clinical outcomes. CONCLUSIONS: Our results demonstrated that cTnI concentration measured 20 h after the end of surgery is an independent predictor of in-hospital death after cardiac surgery. In addition, elevated concentrations of cTnI are associated with a cardiac cause of death and with major postoperative complications.     

Adult cardiac surgery outcomes: role of the pump type.

OBJECTIVE: This study was carried out to evaluate whether the type of pump used for cardiopulmonary bypass (CPB; roller vs. centrifugal) can affect mortality or the neurological outcomes of adult cardiac surgery patients. METHODS: Between 1994 and June 1999, 4000 consecutive patients underwent coronary and/or valve surgery at our hospital; of these, 2213 (55.3%) underwent surgery with centrifugal pump use, while 1787 (44.7%) were operated on with a roller pump. The effect of the type of the pump and of 36 preoperative and intraoperative risk factors for perioperative death, permanent neurological deficit and coma were assessed using univariate and multivariate analyses. RESULTS: The overall in-hospital mortality rate was 2.2% (88/4000), permanent neurological deficit occurred in 2.0% (81/4000) of patients, and coma in 1.3% (52/4000). There was no difference in hospital mortality between patients operated with the use of centrifugal pumps and those operated with roller pumps (50/2213 (2.3%) vs. 38/1787 (2.1%); P=0.86). On the other hand, patients who underwent surgery with centrifugal pumps had lower permanent neurological deficit (34/2213, (1.5%) vs. 47/1787 (2.6%); P=0.020) and coma (20/2213 (0.9%) vs. 32/1787 (1.8%); P=0.020) rates than patients operated with roller pumps. Multivariate analysis showed CPB time, previous TIA and age as risk factors for permanent neurological deficit, while centrifugal pump use emerged as protective. Multivariate risk factors for coma were CPB time, previous vascular surgery and age, while centrifugal pump use was protective. CONCLUSIONS: Centrifugal pump use is associated with a reduced rate of major neurological complications in adult cardiac surgery, although this is not paralleled by a decrease in in-hospital mortality.     

Outcome with high blood lactate levels during cardiopulmonary bypass in adult cardiac operation

Background. High blood lactate levels during cardiopulmonary bypass (CPB) are associated with tissue hypoperfusion and may contribute to postoperative complications or death. The objective of this study was to determine an association between blood lactate levels during CPB and perioperative morbidity and mortality.

Methods. We reviewed 1,376 patients who underwent cardiac operation with CPB. Patients with abnormal preoperative blood lactate levels were excluded (n = 101). Blood lactate concentration during CPB, clinical data, and perioperative events were recorded.

Results. Peak blood lactate levels of 4.0 mmol/L or higher during CPB were present in 227 patients (18.0%). Postoperative mortality was higher in this group than in the patients who had peak blood lactate levels of less than 4.0 mmol/L during CPB (11.0% versus 1.4%; p < 0.001, relative risk [RR] = 9.0). Postoperative hemodynamic instability occurred in 29.5% of patients with elevated levels of lactate during CPB compared with 10.9% of patients with lower lactate levels (p < 0.001, RR = 3.4). Overall, major postoperative complications occurred in 43.2% and 21.8% of patients in each group, respectively (p < 0.001, RR = 2.7). Logistic regression analysis revealed that peak blood lactate levels of 4.0 mmol/L or higher during CPB were strongly associated with postoperative mortality (p = 0.0001) and morbidity (p = 0.013).

Conclusions. Blood lactate concentration of 4.0 mmol/L or higher during CPB identifies a subgroup of patients with increased risk of postoperative morbidity and mortality.     

Postoperative hypoalbuminemia is an independent risk factor for acute kidney injury after cardiac surgery under cardiopulmonary bypass

Objective To investigate the effect of postoperative hypoalbuminemia on acute kidney injury (AKI) after cardiac surgery under cardiopulmonary bypass (CPB). Methods The clinical data of adult patients undergoing cardiac surgery under CPB were retrospectively analyzed. The difference between preoperative and postoperative serum albumin level was compared. The patients were divided into hypoalbuminemia group (≤35 g/L) and non-hypoalbuminemia group (＞35 g/L) according to the lowest serum albumin concentration within 48 hours after surgery. The incidence and severity of postoperative AKI were compared between the two groups. Univariate analysis and binary logistic regression analysis were used to evaluate the effect of postoperative hypoalbuminemia on the incidence of postoperative AKI. Results Among the 749 patients, the serum albumin level after cardiac surgery was significantly lower than that before surgery (Z=-15.739, P＜0.001), and the proportion of patients with hypoalbuminemia increased from 9.6% to 27.6%( χ2=83.516, P＜0.001). Postoperative AKI occurred in 273 patients, including 109 cases (52.7%) in hypoalbuminemia group and 164 cases (30.3%) in non-hypoalbuminemia group. The incidence of AKI in hypoalbuminemia group was significantly higher than that in non-hypoalbuminemia group ( χ2=32.443, P＜0.001), and the severity of AKI in hypoalbuminemia group increased than that in non-hypoalbuminemia group (Z=-2.098, P=0.036), and the time of hospital stay extended (Z=-2.442, P=0.015). After adjusted by gender, age, preoperative hypoalbuminemia, comorbidities (hypertension, hyperuricemia, diabetes mellitus, cerebrovascular disease), renal insufficiency, preoperative heart function, coronary angiography, CPB time, aorta blocking time, type of heart surgery and postoperative hypotension, binary logistic regression analysis revealed that postoperative hypoalbuminemia was an independent risk factor for CPB-associated AKI (OR=2.319, 95%CI 1.586-3.392, P＜0.001). Conclusions AKI is a common complication following cardiac surgery under CPB. Serum albumin after CBP is significantly lower than that before CBP, and postoperative hypoalbuminemia within 48 hours after surgery is an independent risk factor for AKI.     

Atrial fibrillation after cardiac surgery/cardiopulmonary bypass is associated with monocyte activation

Atrial fibrillation (AF) contributes significantly to morbidity and mortality in as many as one-third of patients after cardiac surgery that requires cardiopulmonary bypass (CPB). Recent data suggest that inflammatory infiltration of the myocardium may predispose to AF. We conducted an exploratory pilot study to determine if there was an association between the perioperative leukocyte inflammatory response to cardiac surgery/CPB and postoperative AF. We enrolled 72 patients undergoing cardiac surgery with CPB; all patients were in sinus rhythm before surgery. Leukocyte activation (CD11b upregulation) was perioperatively measured in monocytes and neutrophils (PMN). Preoperative C-reactive protein (CRP) and perioperative neutrophil myeloperoxidase (MPO) were also monitored for inflammation, and troponin I was assayed for perioperative cardiac muscle damage. All markers were evaluated for differences between the subset of patients who developed AF versus those who remained in normal sinus rhythm after surgery. All 72 patients completed the study. Postoperative AF developed in 26 (36%) patients. Perioperative monocyte CD11b upregulation was significantly increased in patients who developed AF (P = 0.01), but increases in PMN CD11b were not significantly associated with AF (P = 0.057). The increase in both monocyte and PMN counts after aortic cross-clamp release was significantly associated with postoperative AF (P = 0.007 and P = 0.005, respectively). By contrast, preoperative CRP and perioperative MPO did not differ between AF and normal rhythm patients. Similarly, the peak value of troponin I did not differ between groups. In this pilot study of cardiac surgery/CPB patients, perioperative upregulation of the monocyte adhesion receptor, CD11b, and higher circulating monocyte and PMN numbers were associated with postoperative AF, suggesting that the induction of cellular inflammation during cardiac surgery/CPB may contribute to this pathophysiology.     

Cardiac troponin I versus creatine kinase-MB in the detection of postoperative cardiac events after coronary artery bypass grafting surgery

AIM: Several studies suggest that postoperarive concentrations of cardiac troponin-I (cTnI) may increase in patients undergoing aorto-coronary bypass grafting (CABG). The degree and pattern of release appears to be associated with perioperative myocardial damage. METHODS: This was a prospective observational study with serial sampling conducted at the Departments of Cardiothoracic Surgery and Anesthesiology, University Hospital of Ioannina, Ioannina, Greece. The levels of cTnI and creatine kinase-MB (CK-MB) preoperatively, upon admission to the intensive care unit and at 12, 24, 36 and 48 hours after surgery, as well as daily from postoperative days 3-7 were determined in 41 consecutive patients (33 males and 8 females, aged 64.8+/-6.1 years) who underwent CABG with cardiopulmonary bypass. The Authors compared the patterns and variation of cTnI and creatine kinase (CK)-MB after CABG in patients with or without postoperative cardiac events (PCEs). RESULTS: Eleven patients experienced a PCE (postoperative ventricular and supraventricular arrhythmia, need for intra-aortic balloon pump (IABP) for >12 hours, or postoperative myocardial infarction, [MI]). In patients without PCE the elevation of cTnI peaked at 24 hours after surgery, while in patients with PCE maximal values of cTnI occurred after 36 hours. CTnI levels correlated with CK-MB after the procedure. Receiver-operating characteristic (ROC) curve analysis indicated that cTnI is superior to CK-MB with regard to PCE diagnosis following CABG (area under the ROC curve, 0.73, 95% CI (0.53-0.93) versus 0.54, 95% CI, (0.25-0.83). CONCLUSION: CTnI seems to be more valuable compared to CK-MB in the detection of PCEs in patients undergoing coronary surgery.