Longer Aortic Cross-clamp Time Research Articles

Point of care serum lactate levels as a prognostic marker of outcome in complex pediatric cardiac surgery patients: Can we utilize it?

Background:Post-operative course after complex pediatric cardiac surgery is unpredictable. Although, change in arterial lactate levels has been used as a surrogate marker for many years, scientific evidence correlating the early perioperative lactate levels with outcome is still lacking.Objective:To evaluate the trends in lactate levels from intraoperative period to an extended post-operative period in pediatric intensive care unit (PICU) and to assess its usefulness as a prognostic marker.Design:Prospective observational study.Setting:Tertiary pediatric cardiac surgical unit.Patients:Thirty-five non-consecutive children aged 1-140 months who underwent surgery for congenital heart diseases (CHD) on cardiopulmonary bypass (CPB).Intervention:None.Materials and Methods:Arterial blood lactate levels were obtained at the following time points: After induction of anesthesia, 15 and 45 min after institution of CPB, at the start of rewarming, after sternotomy closure, then at 1, 6, 24, and 48 h in PICU. Other hemodynamic and clinical variables, CPB variables, blood gas values, and laboratory variables were also recorded.Results:Four patients died out of 35 patients (11.4%). Non-survivors showed significant persistent elevation in lactates (>4.0 mmol/l). Peak lactates correlate significantly with longer aortic cross clamp time, CPB duration, ventilation hours and PICU stay.Conclusion:Early point of care lactate can be a useful prognostic marker in post-cardiac surgery patients in adjunct with other parameters measured in PICU. This reiterates the importance of measuring lactates and timely recognition of at-risk patients, which on early intervention can help in reducing post-operative morbidity and mortality.

Does Gender Affect the Outcomes of Multiple Valve Heart Surgery?

Background: Multiple valve surgery exposes patients to major morbidity and mortality. Little is known about the effect of gender on the outcomes of multiple valve surgery. Methods: In 69 patients who had multiple valve surgery for rheumatic valvular heart disease, 51 patients had mitral and aortic valve replacement, 9 patients had mitral and aortic valve replacement and tricuspid valve repair, 4 patients had mitral valve replacement and tricuspid valve repair, 4 patients had mitral and tricuspid valve repair, and 1 patient had mitral and tricuspid valve replacement. Outcomes were evaluated with univariate analysis. Results: Women had significantly smaller body surface area and smaller left ventricular end-systolic area than men. Women and men had similar left ventricular ejection fraction and New York Heart Association functional class. Univariate analysis showed that in women (but not men), older age, atrial fibrillation, lower left ventricular ejection fraction, and New York Heart Association functional class II and III were associated with longer hospital and intensive care unit stay. In men (but not women), longer cardiopulmonary bypass time was associated with increased left ventricular end-systolic area at 12 months after surgery. Longer aortic cross-clamp time was associated with increased left ventricular end-systolic area in men but only weakly in women. Conclusion: We concluded that gender is an independent predictor of outcomes after multiple valve heart surgery.

Training in mitral valve surgery need not affect early outcomes and midterm survival: a multicentre analysis

Mitral valve surgery may be regarded as less favourable for training, due to greater mortality risk, technical complexity, and difficulty for the supervisor to observe. We examined this perception by reviewing a multicentre experience. We analysed a multicentre database over a 7-year period containing 2216 isolated and combined mitral procedures. Of these, 2048 were performed by consultants and 168 by trainees (92% vs 8%) of varying seniority. Preoperative characteristics, early postoperative outcomes and 6-year survival were compared between groups. Propensity-score matching was performed to correct for group differences. Trainees were less likely to operate on patients, who had previously undergone coronary surgery (consultant 4.3% vs trainee 1.2%, p=0.043) and those with moderate to severe mitral regurgitation (86% vs 81%, p=0.012). There were no other statistically significant differences in preoperative variables, such as urgency, endocarditis and left-ventricular dysfunction. There were similar rates of mitral valve repair (48% vs 51%, p=0.48). Trainees were more likely to operate on rheumatic valve pathology (20% vs 28%, p=0.012). Intra-operatively, trainees had longer aortic cross-clamp times (119 ± 52 vs 136 ± 50 min, p=0.0001). At 30 days, mortality was comparable (4.5% vs 3.6%, p=0.56) with a trend towards higher any mortality/morbidity in consultant procedures (33% vs 26%, p=0.059). At 6 years, survival was similar (79 ± 1.4% vs 78 ± 4.0%, p=0.73). After derivation of 142 propensity-score-matched patient pairs, trainees cases still experienced longer cross-clamp times (121 ± 58 vs 137 ± 52 min, p=0.023), but there was similar 30-day mortality (4.2% vs 3.5%, p>0.99) and any mortality/morbidity (28% vs 24%, p=0.52). Six-year survival between matched pairs was also similar (74 ± 7.2% vs 80 ± 4.4%, p=0.64). Trainee status did not predict early or late adverse events after multivariate Cox regression with and without propensity-score adjustment. Trainee outcomes are not inferior even when corrected for risk. This suggests that excellent operative training and supervision can be achieved in mitral valve surgery.

Analysis of 14,843 Neonatal Congenital Heart Surgical Procedures in the European Association for Cardiothoracic Surgery Congenital Database

Early outcomes of congenital heart surgery in neonates have significantly improved during the last decade. Further improvements require identification of specific risk factors correlating with early mortality and morbidity. Between January 1999 and May 2008 data on 14,843 congenital heart procedures performed in 118 congenital heart surgery centers in 34 countries were submitted to the European Association for Cardiothoracic Surgery Congenital Database. Mean age at surgery was 11.8 days and mean body weight was 2.9 kg. Multivariate stepwise regression analysis was used to assess the risk factors for postoperative complications and death. Thirty-day mortality of 9.1% was significantly different from hospital mortality (10.7%). Postoperative complications occurred in 29.2% of neonates. In multivariate analysis, early death rate was statistically significantly modified by body weight, Aristotle basic score (ABS), cardiopulmonary bypass time (CPB time), aortic cross-clamp time, circulatory arrest time, and univentricular physiology. The rate of complications was associated with ABS, CPB time, and circulatory arrest time. In neonatal congenital heart surgery significant risk of early death extends beyond 30 postoperative days. Multivariate analysis confirmed that lower body weight, higher ABS, longer CPB time, longer aortic cross-clamp time, longer circulatory arrest time, and univentricular physiology are risk factors for hospital mortality. Higher ABS as well as longer CPB time and circulatory arrest time are associated with the rate of complications.

Cardiac-surgery associated acute kidney injury requiring renal replacement therapy. A Spanish retrospective case-cohort study

BackgroundAcute kidney injury is among the most serious complications after cardiac surgery and is associated with an impaired outcome. Multiple factors may concur in the development of this disease. Moreover, severe renal failure requiring renal replacement therapy (RRT) presents a high mortality rate. Consequently, we studied a Spanish cohort of patients to assess the risk factors for RRT in cardiac surgery-associated acute kidney injury (CSA-AKI).MethodsA retrospective case-cohort study in 24 Spanish hospitals. All cases of RRT after cardiac surgery in 2007 were matched in a crude ratio of 1:4 consecutive patients based on age, sex, treated in the same year, at the same hospital and by the same group of surgeons.ResultsWe analyzed the data from 864 patients enrolled in 2007. In multivariate analysis, severe acute kidney injury requiring postoperative RRT was significantly associated with the following variables: lower glomerular filtration rates, less basal haemoglobin, lower left ventricular ejection fraction, diabetes, prior diuretic treatment, urgent surgery, longer aortic cross clamp times, intraoperative administration of aprotinin, and increased number of packed red blood cells (PRBC) transfused. When we conducted a propensity analysis using best-matched of 137 available pairs of patients, prior diuretic treatment, longer aortic cross clamp times and number of PRBC transfused were significantly associated with CSA-AKI.Patients requiring RRT needed longer hospital stays, and suffered higher mortality rates.ConclusionCardiac-surgery associated acute kidney injury requiring RRT is associated with worse outcomes. For this reason, modifiable risk factors should be optimised and higher risk patients for acute kidney injury should be identified before undertaking cardiac surgery.

Epicardial Maze Procedure on the Beating Heart With an Infrared Coagulator

Maze surgery is widely used to treat atrial fibrillation (AF) but requires cardiopulmonary bypass and longer aortic cross-clamping time. Percutaneous transcatheter pulmonary vein (PV) isolation is time consuming and relies on fluoroscopy and contrast media, and PV obstruction and cardiac tamponade are still major problems. To overcome these drawbacks, we developed an epicardial maze procedure with an infrared coagulator on the beating heart, and the aim of this study was to confirm electrophysiologically the efficacy of this method. Light from a lamp in the infrared coagulator is focused into a quartz rod, and the distal exit-plane of the rod is connected to a sapphire tip that allows 10 mm of linear photocoagulation. In an experiment in 5 dogs with AF, instead of making all of the incisions usually required for maze surgery, the infrared coagulator was applied epicardially to create a continuously overlapping linear lesion that was the same as the incision line in the maze III procedure except for the intraatrial incision. After the procedure, 11 electrodes were attached to both atria, and an electrophysiologic study was performed. The electrophysiologic study confirmed electrophysiologic isolation of both atrial appendages and within the PV encircling lesion. Sustained atrial fibrillation could no longer be induced. The epicardial maze procedure was successfully performed on a beating heart with the infrared coagulator.

Lateral tunnel versus extracardiac conduit fontan procedure: a concurrent comparison

Background The aim of this study was to compare the outcomes of the lateral tunnel (LT) and extracardiac conduit (ECC) Fontan procedures at a single institution over the same time period. Methods From November 1995 through October 2002, 70 Fontan procedures were performed: 37 LT and 33 ECC. All were fenestrated; 96% were staged with a prior superior cavopulmonary connection. Compared with the ECC patients, the LT patients were younger (2.7 ± 1.1 vs 3.9 ± 2.5 years; p = 0.01), had a higher incidence of hypoplastic left heart syndrome (57% vs 21%; p < 0.01), and a longer aortic cross-clamp time (55 ± 13 vs 26 ± 15 min; p < 0.01). Weight, gender, preoperative cardiac catheterization values, and cardiopulmonary bypass time did not differ between the two groups. Results Operative mortality was 2.8%, 1 patient in each group ( p = 1.0). Over the first 24 hours following operation the mean Fontan pressure, transpulmonary gradient, and common atrial pressure did not differ between LT and ECC patients. The median duration of mechanical ventilation (LT 12 vs ECC 18 hours), intensive care unit stay (LT 2 vs ECC 3 days), chest tube drainage (LT 10 vs ECC 8 days), and hospital stay (LT 11 vs ECC 12 days) did not differ. The ECC patients had a higher incidence of sinus node dysfunction both in the postoperative period (27% vs LT 8%; p = 0.09), and persisting at hospital discharge (10% vs LT 0%; p = 0.02). Mean follow-up was 3.6 ± 1.6 years in LT, and 3.0 ± 2.2 years in ECC patients ( p = 0.2). There was one late death. Actuarial survival at 5 years is 97% for LT, and 91% for ECC patients ( p = 0.4); 96% of patients are in NYHA class I, and 4% in class II, with no difference between groups. Sinus node dysfunction was seen during follow-up in 15% LT vs 28% ECC patients ( p = 0.2). Conclusions The LT and ECC approaches had comparable early and mid-term outcomes, including operative morbidity and mortality, postoperative hemodynamics, resource use, and mid-term survival and functional status. ECC patients had a higher incidence of sinus node dysfunction early after operation.

Influence of bilateral skeletonized harvesting on occurrence of deep sternal wound infection in 1,000 consecutive patients undergoing bilateral internal thoracic artery grafting.

To evaluate the risk of deep sternal infection in a large patient cohort following bilateral internal thoracic artery (BITA) grafting using skeletonized BITA dissection. Complete myocardial revascularization using BITAs improves long-term survival and lowers the rate of repeat operations. Harvesting of ITAs as skeletonized vessels preserves sternal collateral blood supply, thus enabling rapid sternal healing with less risk of deep sternal infection. One thousand consecutive patients (763 men, 340 patients >70 years old, 304 diabetics) underwent skeletonized BITA grafting from April 1996 to July 1999. The 30-day mortality rate was 3.4%. There were 10 perioperative infarcts, 16 strokes, and 22 deep sternal infections. There was an increased risk of deep sternal infection in repeat coronary artery bypass grafting (CABG) operations (15%), chronic obstructive pulmonary disease (COPD) (6.2%), congestive heart failure (4.7%), left ventricular dysfunction (ejection fraction < 35%, 4.5%), and longer aortic cross-clamping time. After adjustment for other demographic, clinical, and surgical predictors, the only independent predictors of deep sternal infection were repeat operations, COPD, and duration of aortic cross-clamping. No patients in the reoperation subgroup died, but three of six COPD patients with deep sternal infection died, and COPD was an independent predictor of overall (early + late) mortality. Skeletonized BITA grafting carries an acceptable risk of deep sternal infection but is not recommended for repeat CABG or for patients with COPD.

Risk factors to hospital mortality in valvar reoperations

OBJECTIVE: Analyze the risk factors for hospital mortality in valvar reoperations. METHOD: A prospective analysis was performed of 194 patients that underwent valvar reoperations between July 1995 and June 1999. The following variables were analyzed: gender, age, functional class, number and type of previous operations, cardiac rhythm, urgency at operation, creatinine level, left ventricular ejection fraction, left ventricular systolic and diastolic diameters, right ventricular systolic pressure, prothrombin activity, activated partial thromboplastin time relation, platelet count, cardiopulmonary bypass time, aortic cross-clamp time, number and position of valves, type of procedure, associated procedures and intraoperative bleeding volume. Univariate and multivariate statistical analyses were performed to determine the risk factors for hospital mortality. RESULTS: The overall hospital mortality was 8.8% (17 patients). Univariate analysis showed that the following variables were associated with higher mortality rates: advanced New York Heart Association functional class, decreased left ventricular ejection fraction, decreased prothrombin activity, increased creatinine level, longer aortic cross-clamping time, prolonged cardiopulmonary bypass time, concomitant associated procedures, and higher intraoperative bleeding volume. Logistic multivariate analysis identified advanced New York Heart Association functional class, creatinine level higher than 1.5 mg/dl, and cardiopulmonary bypass time longer than 120 minutes as independent predictors of hospital mortality. CONCLUSIONS: The variables functional class IV, creatinine level > 1.5 mg/dl and cardiopulmonary bypass time > 120 min were independent predictors of hospital mortality in valvar reoperations.

Cardiac troponin I in neonates undergoing the arterial switch operation

Background Cardiac troponin I (TnI) is a sensitive and specific marker of myocardial injury, but little is known about its release after complex congenital heart surgery. We investigated whether TnI correlates with early clinical outcome in neonates undergoing the arterial switch operation (ASO) for transposition of the great arteries (TGA). Methods Troponin I was measured serially up to 48 hours postoperatively in 31 neonates undergoing the ASO alone (simple TGA) and 9 neonates undergoing the ASO combined with other procedures (complex TGA) (eg, closure of a ventricular septal defect) and correlated with intraoperative and postoperative clinical parameters. Results There was no mortality. Troponin I peaked at either 4 or 12 hours postoperatively in all patients (median for simple TGA = 3.4 ng/mL, interquartile range 2.4 to 4.6; median for complex TGA = 4.7 ng/mL, interquartile range 3.2 to 6.8, p = 0.20). Peak TnI correlated with the durations of inotropic support ( r = 0.54, p < 0.001), ventilation ( r = 0.51, p < 0.01), and intensive care unit stay ( r = 0.50, p < 0.01). The duration of cardiopulmonary bypass, aortic cross-clamping, and circulatory arrest did not correlate with the peak or total TnI release. The duration of aortic cross-clamping correlated poorly with the duration of inotropic support ( r = 0.40, p < 0.05). The complex TGA group had longer aortic cross-clamp times, required more postoperative inotropic support, and had significantly higher total TnI release compared with the simple TGA group. Conclusions There are weak but statistically significant correlations between peak TnI and clinical outcome. Complexity of the defect and ischemic times may be as useful to predict outcome in this group of patients.

Minimal access aortic valve replacement: effects on morbidity and resource utilization

Background The aim of this study was to compare outcomes in patients undergoing minimal access versus conventional aortic valve replacement (AVR). Methods We reviewed prospectively gathered data on all patients who were undergoing first-time AVR, with or without replacement of the ascending aorta, over a 1-year period at our institution. Results A total of 176 patients underwent minimal access and 258 underwent conventional AVR. The conventional group was older, had more incidence of diabetes, and more aortic stenosis (all p < 0.05). Eight minimal access AVR patients (2%) required conversion to a complete sternotomy. Minimal access AVR patients had longer aortic crossclamp times than conventional AVR patients (60 ± 22 vs 55 ± 23 minutes, p = 0.03) but similar CPB times (93 ± 38 vs 88 ± 42 minutes, p = 0.20). Postoperative creatine kinase–MB levels were similar for the two groups. Total postoperative blood loss was significantly lower in the minimal access group, and these patients received less red blood cell and fresh frozen plasma transfusions. Minimal access AVR patients were less likely to have postoperative respiratory failure (3% vs 10%); they had shorter intensive care unit stays (3.7 ± 5.4 vs 4.5 ± 5.6 days) and shorter hospital stays (10 ± 6 vs 12 ± 7 days, all p < 0.05). Mortality was lower in patients undergoing minimal access surgery (3% vs 9%, p = 0.008) by univariate analysis. Multivariate predictors of mortality were age, hypertension, and CPB time. Conclusions Although patient selection may have influenced some of the observed differences between our patient groups, minimal access surgery appears to be associated with decreased morbidity and resource use when compared to conventional AVR.

Fatores de risco para mortalidade hospitalar nas reoperações valvares

OBJETIVO: Identificar fatores de risco para mortalidade hospitalar em reoperações valvares. MÉTODO: Foi realizada análise prospectiva de 194 pacientes submetidos a reoperações valvares no período entre julho de 1995 e junho de 1999. As variáveis estudadas foram: sexo, idade, classe funcional, número e tipo de operações prévias, intervalo entre as operações, caráter da operação, creatinina sérica, fração de ejeção do ventrículo esquerdo, diâmetros diastólico e sistólico do ventrículo esquerdo, pressão sistólica de ventrículo direito, atividade de protrombina, relação do tempo de tromboplastina parcial ativada, contagem de plaquetas, tempo de circulação extracorpórea, tempo de pinçamento aórtico, posição e número de valvas, tipo de procedimento, operações associadas e volume de sangramento intra-operatório. Análise univariada e multivariada foi realizada para determinar os fatores de risco para mortalidade hospitalar. RESULTADOS: A mortalidade hospitalar foi de 8,8% (17 pacientes). A análise univariada identificou as seguintes variáveis associadas a maior mortalidade: classe funcional avançada, fração de ejeção do ventrículo esquerdo baixa, atividade de protrombina baixa, creatinina elevada, tempo de circulação extracorpórea prolongado, tempo de pinçamento aórtico prolongado, procedimentos associados e volume de sangramento intra-operatório elevado. Na análise multivariada foram significativas: classe funcional IV, creatinina > 1,5 mg/dl e tempo de circulação extracorpórea > 120 minutos. CONCLUSÕES: As variáveis classe funcional IV, creatinina > 1,5 mg/dl e tempo de circulação extracorpórea > 120 minutos são fatores de risco independentes para mortalidade hospitalar nas reoperações valvares.

The modified fontan operation: An analysis of risk factors for early postoperative death or takedown in 702 consecutive patients from one institution

To better understand risk factors associated with early postoperative death or failure, we reviewed our entire experience with 702 consecutive patients who had the modified Fontan operation at the Mayo Clinic between October 1973 and December 1989. The event rate for takedown of repair or death during the initial hospitalization or within 30 days of the operation was 14.8% (successful takedown of the repair, n = 6; death, n = 98). To identify variables associated with early death or Fontan takedown, we analyzed 33 clinical and hemodynamic variables in a univariate and multivariate manner. On the basis of a stepwise logistic discriminant analysis, patients who were younger and operated on before 1980 with a higher preoperative pulmonary artery mean pressure, asplenia, higher intraoperative (after Fontan operation) right atrial pressure, longer aortic crossclamp time, and pulmonary artery ligation were more likely to have the outcome event of interest ( p values < 0.05). A new variable, corrected pulmonary artery pressure (that is, mean preoperative pulmonary artery pressure divided by the ratio of pulmonary to systemic flow if the ratio of pulmonary to systemic flow is greater than 1.0), was significantly associated with the outcome event univariately ( p = 0.002), but was no more predictive than the preoperative pulmonary artery mean pressure. Variables less predictive of the outcome event in this analysis included multiple prior operations, polysplenia syndrome, complex anatomy other than asplenia syndrome, and systemic atrioventricular valve regurgitation. These results represent the largest single-institution review of the Fontan operation and suggest that some anatomic and hemodynamic variables previously predictive of poor early outcome have been nullified by current operative methods. (J T HORAC C ARDIOVASC S URG 1995;109:1237-43)

Descending Aortic Aneurysm Repair Utilizing Moderate Hypothermia (30°C) in Conjunction with Left Heart Bypass

Thoracic and thoracoabdominal aortic aneurysm repair are frequently associated with ischemic paraplegia, renal failure and death. In order to decrease the incidence of ischemic events and allow for a longer aortic cross clamp time, we combined our previous technique of segmental sequential repair, left heart bypass and cerebral spinal fluid drainage in conjunction with moderate hypothermia (30°C). Twenty-seven adult patients underwent elective thoracic (n=6) or thoracoabdominal (n=21) aortic aneurysm repair from January 1992 to September 1993 utilizing this hypothermic technique. A heat exchanger was integrated in the centrifugal left heart bypass circuit to achieve moderate hypothermia (30°C) and regain normothermia (37°C) prior to partial bypass termination. Cannulation for left heart bypass was aortafemoral artery (n=10) or left atrium-femoral artery (n=17). The surgical technique of segmental sequential repair helps to minimize visceral, kidney and spinal cord ischemia. Among these 27 patients, one developed delayed paraplegia on postoperative day #3 and three suffered postoperative death. The average aortic cross clamp time was 76 ± 7 minutes. Previous studies have demonstrated a significant increase of ischemic morbidity (11-25%) when cross clamp times exceeded 30 minutes. We conclude that the combination of left heart bypass, moderate hypothermia and cerebral spinal fluid drainage allow for a longer duration of aortic cross clamp time and a relatively low incidence of ischemic complications.

Value of C-reactive protein in reflecting the magnitude of complement activation in children undergoing open heart surgery

The kinetics of C-reactive protein (CRP) were studied prospectively in 30 children (aged 21 days - 16 years) undergoing open heart surgery. CRP was related to the kinetics of total haemolytic complement, complement C3a and postoperative complications. Two (7%) patients died and ten (33%) had postoperative complications. The patients with complications were younger (p less than 0.035), underwent longer perfusions (p less than 0.001) and had longer aortic cross-clamping times (p less than 0.003). The mean peak CRP level after surgery (108 mg/l) was reached, on the average, in 43 h. No statistical difference in CRP concentrations was found between the complication and non-complication groups. Extensive complement activation was seen in every patient. CRP did not reflect the magnitude of complement activation induced by cardiopulmonary bypass. The patient sample was too small to draw reliable conclusions about the value of CRP in detecting postoperative complications after open heart surgery in children.

Risk factors for myocardial infarction during coronary artery bypass graft surgery

Patients with a particular thrombotic profile may be at greater risk of myocardial infarction during coronary artery bypass graft surgery. The thrombotic profile of 50 patients admitted to hospital with stable angina pectoris was determined prior to haemodynamic investigation. ECG results and determination of cardiac enzymes showed that 12 patients had suffered a perioperative myocardial infarction. These patients had a higher mean atherosclerotic score (42.1 +/- 10.5 vs 32.9 +/- 13, P less than 0.02), a longer aortic cross clamp time (59 +/- 15.2 vs 45.7 +/- 16.3 min, P less than 0.05), lower serum levels of protein C (101.2 +/- 26 vs 124.7 +/- 31.4%, P less than 0.05) and tissue plasminogen activator (322 +/- 580 vs 2307 +/- 2830 IU ml-1, P less than 0.01). There were no differences between the two groups in Jenkin's coronary score, the number and type of grafts, ejection fraction, left ventricular end-diastolic pressure, lipid profile or levels of markers of platelet release. In addition to a more severe distal coronary atheroma and a longer aortic cross-clamp time, patients with impaired endothelial fibrinolytic activity appeared to be at greater risk of myocardial infarction during coronary artery bypass graft surgery.

Prolonged mechanical ventilation of infants after open heart surgery.

Records of 140 infants younger than 2 yr of age who had undergone open heart surgery were studied to evaluate the duration of postoperative mechanical ventilation (MV), to determine the relationship between prolonged MV and mortality, and to identify variables predisposing the patient to prolonged MV. MV was required beyond the first postoperative day in 56 infants, and was prolonged for at least 7 days in 19 infants. Mortality was approximately the same (16% to 17%) whether or not MV was required for more than 7 days. Preoperative and intraoperative variables associated with longer MV included younger age, longer cardiopulmonary bypass time, longer aortic cross-clamp time, and preoperative MV. Multiple predisposing factors increased the probability of prolonged MV. Postoperative variables including premature extubation and a second surgical procedure also were associated with prolonged MV. The consequences of prolonged MV may be minimized by early nutritional support, aggressive surveillance for treatable complications, and avoidance of premature extubation.