Deep sternal wound infection after bilateral internal thoracic artery grafting: Insights from a Japanese national database

Objectives

Despite its survival benefits, bilateral internal thoracic artery (BITA) grafting is not commonly utilized due to concerns over deep sternal wound infection (DSWI). The present study investigated the early outcome of BITA grafting and analyzed the risk of DSWI using a Japanese national database (the Japan Adult Cardiovascular Surgery Database).

Does bilateral ITA grafting increase perioperative complications? Outcome of 4462 patients with bilateral versus 4204 patients with single ITA bypass.

OBJECTIVE: Superior patency of internal thoracic artery (ITA) grafting to saphenous veins is conclusive. The aim of the present study was to compare the early outcome of patients receiving either bilateral ITA (BITA) or single ITA (SITA) grafts and to identify risk factors for perioperative complications, such as obesity, diabetes mellitus, or advanced age. METHODS: All 8666 patients with isolated coronary artery bypass grafting (CABG, including emergent cases or redos) operated between January 1994 and June 2004 receiving either BITA (n=4462) or SITA (n=4204) grafting were analyzed retrospectively. Demographic data were comparable for both groups concerning mean age (65.3+/-9.4 years vs 64.9+/-9.3 years), range (35-89 years (p=0.05)), diabetes incidence (29.3% vs 2.6% (p=0.08)), dialysis-dependent renal failure (0.7% vs 0.6% (p=0.4)), preoperative ejection fraction (EF) mean (61.8% vs 61.2% (p=0.07)) but not for gender (80.4% vs 76.7% males (p=0.00)), body mass index (BMI) mean (27.2+/-3.6 vs 26.9+/-3.5 (p=0.00)), COPD (7.0% vs 8.5% (p=0.00)), and hyperlipidemia (78.3% vs 74.3% (p=0.00)). In the BITA group, right ITA (RITA) was directed preferentially to the left anterior descending artery (LAD), left ITA (LITA) to the lateral wall. In the SITA group, the LAD was revascularized with the left ITA. Additional bypasses were performed with saphenous vein grafts (SVG). RESULTS: The number of anastomoses was higher in the BITA group (3.8+/-0.9 vs 3.1+/-0.9 (p=0.00)); therefore, duration of surgery (mean: 189+/-46.3 min vs 164+/-46.2 min) and cross-clamp time (62.0+/-17.9 min vs 51.0+/-18.0 min) significantly prolonged (p=0.00). Incidence of rethoracotomy due to bleeding (2.9% vs 0.6%; p=0.00) or sternal refixation with (0.7% vs 0.2%; p=0.00) or without infection (1.4% vs 0.6%; p=0.00) was higher in the BITA group, strongly associated with diabetes mellitus and duration of surgery but not with BMI>27. Thirty-day mortality revealed 2.6% versus 3.2% (p=0.1) but was significantly lower for diabetic patients in the BITA group (3.1% vs 4.7%; p=0.00). CONCLUSIONS: CABG using both ITAs can be performed routinely with good clinical results and low mortality. Compared with single ITA grafting, sternal and bleeding complications were slightly increased. Diabetes mellitus, BITA grafting, duration of surgery but not obesity or COPD could be identified as independent risk factors for sternal complications. Dialysis-dependent renal failure, EF<30%, emergent cases, and the absence of BITA grafting were predictors for increased perioperative mortality.     

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

OBJECTIVE: To evaluate the risk of deep sternal infection in a large patient cohort following bilateral internal thoracic artery (BITA) grafting using skeletonized BITA dissection. SUMMARY BACKGROUND DATA: 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. METHODS: One thousand consecutive patients (763 men, 340 patients >70 years old, 304 diabetics) underwent skeletonized BITA grafting from April 1996 to July 1999. RESULTS: 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. CONCLUSIONS: Skeletonized BITA grafting carries an acceptable risk of deep sternal infection but is not recommended for repeat CABG or for patients with COPD.     

Risk analysis of deep sternal wound infections and their impact on long-term survival: a propensity analysis

The objectives of this study are to determine risk factors associated with deep sternal wound infections (DSWIs) following cardiac surgery, and to describe their impact on long-term survival. Data was obtained from a departmental database. Analysis included 7,978 consecutive patients who underwent cardiac surgery between 1997 and 2003. To identify risk factors for DSWI, regression analysis was performed. The probability scores obtained from logistic regression were used for propensity analysis of 2 groups. Kaplan-Meier analysis with log-rank test and Cox proportional hazard models were then used in survival analysis. DSWI developed in 123 of 7,978 patients (1.5%). Preoperative predictors of DSWI were body mass index >30 kg/m(2) (odds ratio [OR], 1.6; 95% confidence interval [CI], 1.1 to 2.4; P < 0.05), diabetes mellitus (OR, 2.4; 95% CI, 1.6 to 3.4; P < 0.001), urgent operation (OR, 1.7; 95% CI, 1.2 to 2.6; P < 0.05), smoking history within past year (OR, 2.7; 95% CI, 1.5 to 4.9; P < 0.001), smoking history within past 2 weeks (OR, 2.6; 95% CI, 1.5 to 4.5; P < 0.001), and a history of stroke (OR, 1.9; 95% CI, 1.1 to 3.1; P < 0.005). In addition, total length of hospital stay (OR, 1.01; 95% CI, 1.01 to 1.02; P < 0.05) and sepsis and/or endocarditis following surgery (OR, 5.1; 95% CI, 2.9 to 9.0; P < 0.001) were also predictive of DSWI. Patients with DSWI had a prolonged total length of hospital stay (40.3 days versus 16.1 days; P < 0.001), and higher 30-day mortality (1.6% versus 7.3% in DSWI group, P < 0.05). There were no differences between groups in 4-year and 8-year survival rates, with 77.2% and 61.8%, respectively, in patients with DSWI compared with 78.0% and 67.5% in patients without DSWI (P = 0.16). After adjustments for preoperative, intraoperative, and postoperative factors, the adjusted hazard ratio of long-term mortality for patients with DSWI was 0.9 (95% CI, 0.6 to 1.2, P = 0.39). Though DSWIs are associated with increased early mortality, patients undergoing cardiac surgery complicated by DSWI do not experience worse long-term survival.     

Deep sternal wound infection requiring revision surgery: impact on mid-term survival following cardiac surgery.

OBJECTIVE: To assess the impact of deep sternal wound infection on in-hospital mortality and mid-term survival following adult cardiac surgery. METHODS: Prospectively collected data on 4586 consecutive patients who underwent a cardiac surgical procedure via a median sternotomy from 1st January 2001 to 31st December 2005 were analysed. Patients with a deep sternal wound infection (DSWI) were identified in accordance with the Centres for Disease Control and Prevention guidelines. Nineteen variables (patient-related, operative and postoperative) were analysed. Logistic regression analysis was used to calculate a propensity score for each patient. Late survival data were obtained from the UK Central Cardiac Audit Database. Mean follow-up of DSWI patients was 2.28 years. RESULTS: DSWI requiring revision surgery developed in 1.65% (76/4586) patients. Stepwise multivariable logistic regression analysis identified age, diabetes, a smoking history and ventilation time as independent predictors of a DSWI. DSWI patients were more likely to develop renal failure, require reventilation and a tracheostomy postoperatively. Treatment included vacuum assisted closure therapy in 81.5% (62/76) patients and sternectomy with musculocutaneous flap reconstruction in 35.5% (27/76) patients. In-hospital mortality was 9.2% (7/76) in DSWI patients and 3.7% (167/4510) in non-DSWI patients (OR 1.300 (0.434-3.894) p=0.639). Survival with Cox regression analysis with mean propensity score (co-variate) showed freedom from all-cause mortality in DSWI at 1, 2, 3 and 4 years was 91%, 89%, 84% and 79%, respectively compared with 95%, 93%, 90% and 86%, respectively for patients without DSWI ((p=0.082) HR 1.59 95% CI (0.94-2.68)). CONCLUSION: DSWI is not an independent predictor of a higher in-hospital mortality or reduced mid-term survival following cardiac surgery in this population.     

Skeletonization of bilateral internal thoracic artery grafts lowers the risk of sternal infection in patients with diabetes

OBJECTIVE: Deep sternal wound infection is a dreaded complication of coronary artery bypass surgery, particularly in patients with diabetes. This study determines whether skeletonization of internal thoracic artery conduits compared with pedicled harvesting reduces the risk of deep sternal wound infection in patients with diabetes undergoing bilateral internal thoracic artery grafting. METHODS: We reviewed prospectively gathered data on all patients who have undergone coronary artery bypass grafting and received bilateral internal thoracic artery grafts at our institution since 1990. We compared patients with diabetes who received skeletonized (n = 79) versus conventional pedicled (n = 36) internal thoracic artery conduits. RESULTS: The proportion of patients taking insulin (19.0% vs 14.0% for skeletonized vs conventional grafts, respectively, P =.6) or oral hypoglycemic agents (68.4% vs 69.4%, P =.9), as well as the prevalence of type I diabetes (2.5% vs 8.3%, P =.18), were similar in both groups. Patients who received skeletonized grafts were more likely to receive a free rather than an in situ right internal thoracic artery graft (93.7% vs 30.6%, P <.001). The prevalence of deep sternal wound infection was significantly lower in patients who received skeletonized grafts compared with patients who received conventional grafts (1.3% vs 11.1%, P =.03). Patients in the skeletonized group were also less likely to develop any (superficial or deep) sternal wound infection postoperatively (5.1% vs 22.2%, P =.03). There was no significant difference in the prevalence of deep sternal wound infection between patients with diabetes who received skeletonized internal thoracic arteries and patients without diabetes who underwent conventional internal thoracic artery grafting (n = 578) (1.2% vs 1.6%, respectively, P =.8). CONCLUSIONS: Skeletonization of internal thoracic artery conduits lowers the risk of deep sternal wound infection in patients with diabetes undergoing bilateral internal thoracic artery grafting. We no longer consider diabetes a contraindication to bilateral internal thoracic artery grafting, provided the internal thoracic arteries are skeletonized.     

Management of closed sternal incision after bilateral internal thoracic artery grafting with a single-use negative pressure system

Single-use, closed incision management (CIM) systems offer a practical means of delivering negative pressure wound therapy to patients. This prospective study evaluates the Prevena? Therapy system in a cohort of coronary patients at high risk of deep sternal wound infection (DSWI). Fifty-three consecutive patients undergoing bilateral internal thoracic artery (BITA) grafting were preoperatively elected for CIM with the Prevena? Therapy system, which was applied immediately after surgery. The actual rate of DSWI in these patients was compared with the expected risk of DSWI according to two scoring systems specifically created to predict either DSWI after BITA grafting (Gatti score) or major infections after cardiac surgery (Fowler score). The actual rate of DSWI was lower than the expected risk of DSWI by the Gatti score (3.8 vs. 5.8%, p = 0.047) but higher than by the Fowler score (2.3%, p = 0.069). However, while the Gatti score showed very good calibration (χ² = 4.8, p = 0.69) and discriminatory power (area under the receiver-operating characteristic curve 0.838), the Fowler score showed discrete calibration (χ² = 10.5, p = 0.23) and low discriminatory power (area under the receiver-operating characteristic curve 0.608). Single-use CIM systems appear to be useful to reduce the risk of DSWI after BITA grafting. More studies have to be performed to make stronger this finding.     

Is Bilateral Internal Thoracic Artery Use Safe in the Elderly?

Abstract Background: The strategy of bilateral mammary artery grafting is often not considered for elderly patients due to perceived concerns of increased morbidity and mortality. The objective of this study is to explore the safety of bilateral mammary in elderly patients. Methods: Out of 7746 patients who underwent coronary artery bypass grafting using at least one internal thoracic artery (ITA), there were 3940 patients aged 65 years or greater, and of those, 3581 patients had a single ITA (SITA) and 359 patients had bilateral ITAs (BITAs). The primary outcome was the incidence of major adverse cardiac or cerebrovascular events (MACCEs). Secondary outcomes included re‐exploration for bleeding, blood transfusions, sternal wound infections, and intensive care unit and hospital length of stay. Results: The incidence of mortality and MACCE were similar in both groups (mortality BITA 2.6%, SITA 3.6%, p = 0.25, MACCE BITA 8.5%, SITA 6.1%, p = 0.13). Superficial and deep sternal site infections were significantly more prevalent in the BITA group than the SITA group [superficial OR 0.42, 95% CI [0.23 – 0.75] (p = 0.003) and deep OR 0.29, 95% CI [0.14 – 0.58 (p = 0.0005)]. Conclusion: Use of BITA is safe in the elderly with respect to mortality and early cardiovascular outcome. BITA use in the elderly is associated with an increased risk of sternal wound infection. Our experience in this situation suggests that there is a maximum age (approximately 74 years) beyond which the combined risk of MACCE and wound complications supersedes the benefits in terms of sternal infections. (J Card Surg 2012;27:1‐5)     

Analysis of risk factors for myocardial infarction and cardiac mortality after major vascular surgery

BACKGROUND: Patients undergoing vascular surgical procedures are at high risk for perioperative myocardial infarction (PMI). This study was undertaken to identify predictors of PMI and in-hospital death in major vascular surgical patients. METHODS: From the Vascular Surgery Registry (6,948 operations from January 1989 through June 1997) the authors identified 107 patients in whom PMI developed during the same hospital stay. Case-control patients (patients without PMI) were matched at a 1x:x1 ratio with index cases according to the type of surgery, gender, patient age, and year of surgery. The authors analyzed data regarding preoperative cardiac disease and surgical and anesthetic factors to study association with PMI and cardiac death. RESULTS: By using univariable analysis the authors identified the following predictors of PMI: valvular disease (P = 0.007), previous congestive heart failure (P = 0.04), emergency surgery (P = 0.02), general anesthesia (P = 0.03), preoperative history of coronary artery disease (P = 0.001), preoperative treatment with beta-blockers (P = 0.003), lower preoperative (P = 0.03) and postoperative (P = 0.002) hemoglobin concentrations, increased bleeding rate (as assessed from increased cell salvage; P = 0.025), and lower ejection fraction (P = 0.02). Of the 107 patients with PMI, 20.6% died of cardiac cause during the same hospital stay. The following factors increased the odds ratios for cardiac death: age (P = 0.001), recent congestive heart failure (P = 0.01), type of surgery (P = 0.04), emergency surgery (P = 0.02), lower intraoperative diastolic blood pressure (P = 0.001), new intraoperative ST-T changes (P = 0.01), and increased intraoperative use of blood (P = 0.005). Patients who underwent coronary artery bypass grafting, even more than 12 months before index surgery, had a 79% reduction in risk of death if they had PMI (P = 0.01). Multivariable analysis revealed preoperative definitive diagnosis of coronary artery disease (P = 0.001) and significant valvular disease (P = 0.03) were associated with increased risk of PMI. Congestive heart failure less than 1 yr before index vascular surgery (P = 0. 0002) and increased intraoperative use of blood (P = 0.007) were associated with cardiac death. The history of coronary artery bypass grafting reduced the risk of cardiac death (P = 0.04) in patients with PMI. CONCLUSIONS: The in-hospital cardiac mortality rate is high for patients who undergo vascular surgery and experience clinically significant PMI. Stress of surgery (increased intraoperative bleeding and aortic, peripheral vascular, and emergency surgery), poor preoperative cardiac functional status (congestive heart failure, lower ejection fraction, diagnosis of coronary artery disease), and preoperative history of coronary artery bypass grafting are the factors that determine perioperative cardiac morbidity and mortality rates.     

Sternal closure techniques and postoperative sternal wound complications in elderly patients.

OBJECTIVE: Postoperative sternal wound complications (PSWC) including deep sternal wound infection (DSWI) and sternal dehiscence (SD) cause significant morbidity and mortality. Elderly patients with several risk factors are particularly prone to suffer PSWC. METHODS: We present (I) a subset of 86 patients, all aged > or =75 years out of 339 cardiac surgery patients prospectively randomised to receive either conventional sternal closure or a Robicsek type closure. Primary end-points were SD and DSWI; secondary end-points included a composite of clinical parameters; (II) we retrospectively assessed data of 54/5273 patients with mediastinitis regarding the influence of advanced age. In addition, we report an epidemiological overview of different sternal closure techniques. RESULTS: (I) The Robicsek technique showed an impact on SD and DSWI, and several secondary end-points: ventilator support (p=0.03), postoperative blood loss (p=0.04), and chest pain >3 days (p=0.04). (II) A total of 54/5273 (1.02%) patients developed postoperative mediastinitis. Twelve out of 54 (22%) patients died within 6 months of the initial operation. Predictors of mortality were insulin-dependent diabetes mellitus (p=0.05), renal insufficiency (p=0.01), delayed sternal closure (p=0.05), ICU-stay >10 days (p=0.01), and methicillin-resistant Staphylococcus aureus (p=0.03) or fungal infection (p=0.02). CONCLUSIONS: No statistical difference in sternal dehiscence or mediastinitis was found irrespective of whether the bilateral and longitudinal parasternal closure or the conventional peri/trans-sternal wiring technique was used, but there was an obvious, positive influence on sternal dehiscence, deep sternal wound infection, and clinical parameters. However, the study population is relatively small.     

Bilateral internal thoracic artery grafting in insulin-treated diabetics: should it be avoided?

BACKGROUND: It has been advocated that skeletonized bilateral internal thoracic artery (BITA) grafting may be implemented safely in diabetics, thus bestowing these patients with the long-term benefits of this strategy. However, the feasibility of this approach in insulin-treated patients has yet to be determined. METHODS: One-hundred twenty-four insulin-treated diabetics, operated on between April 1996 and December 2001, were compared according to the surgical technique used: BITA (n = 50) or single internal thoracic artery (SITA; n = 74). In the latter, complementary grafts used were saphenous veins and radial arteries. RESULTS: The groups had comparable risk profiles, with the exception of more neurologic events in the SITA group (21% vs 4%, p = 0.008). There was no significant difference in 30-day mortality (6% vs 4%, p = 0.684), nor in the incidence of neurologic complications (2% vs 8%, p = 0.240). The rate of sternal infection was comparable (4% vs 2.7%, p = 1.000). Use of BITAs was associated with a lower return of angina (4% vs 20%, p = 0.025), less cardiac events (17% vs 38%, p = 0.01), and reduced cardiac mortality (none vs 10%, p = 0.04). Despite the similar 6-year survival (80.5% and 77.4%, p = NS), cardiac-related event-free survival was better in BITA patients (69% vs 23%, p < 0.0001). Multivariate analysis identified use of BITA as a protective factor resulting in less return of angina (p = 0.007) and improved cardiac-related event-free survival (p = 0.001). CONCLUSIONS: Skeletonized BITA grafting can be performed in insulin-treated diabetics at acceptable risk. This approach may confer improved cardiac outcome. Thus, it should be considered in selected patients.     

What Is the Mortality and Recuperative Difference of Bilateral Versus Single Thoracic Artery Coronary Revascularization in Patients with Reoperation or Over 80 Years of Age?†

BACKGROUND: We examined whether bilateral internal thoracic artery revascularization (BITA) is safe for reoperative coronary revascularization (reop CABG) or primary CABG at age > or = 80 (CABG > or = 80 yrs) as, these two groups are thought to be at higher risk for death or sternal infection. METHODS: We analyzed 329 such patients between January 1, 1993 and March 31, 2002. These are subgroups of 3200 prospectively New York State risk stratified patients for BITA or SITA (single internal thoracic artery revascularization) of equivalent preoperative risk. In 37/39, BITA > or = 80 since 1996 (1996 > or = 80) the microscope was used and the free right internal thoracic artery was anastomosed to the aorta. Long-term survival was analyzed by Kaplan-Meier curves and in particular among the 36 patients between 1996 and 1997, who were operated five and six years ago (1997 > or = 80). CONCLUSIONS: Mortality and recuperative difference of BITA versus SITA in the reop CABG and CABG > or = 80 years are negligible, as there was no significant difference in hospital mortality, sternal infections, LOS, or Kaplan-Meier survival curves and average long-term survival. However BITA appears to have long-term advantage over SITA in the newer period and beyond 48 months (1996-1997 > or = 80).     

Vacuum-assisted closure therapy for deep sternal wound infections: the impact of learning curve on survival and predictors for late mortality

The aim of this study was to evaluate the possible learning curve effects on survival during the introduction of vacuum-assisted closure (VAC) therapy in patients with deep sternal wound infection (DSWI). Furthermore, predictors of late mortality were analysed and causes of late death were examined. Fifty-three patients (early Group, n = 26, January 1999 to July 2001 versus late group, n = 27, August 2001 to March 2003) were all treated with VAC for DSWI. A follow-up was carried out in September 2006. Multivariate analyses were used to evaluate the predictors of late mortality. The 90-day mortality was 0% in both groups. The survival rates at 5 years were 69.2 +/- 9.1% (early group) versus 58.5 +/- 11.7% (late group), P = ns (non significant). The time interval from cardiac surgery to diagnosis of DSWI and prolonged VAC therapy were identified as independent predictors of late mortality. Our concept for VAC therapy in DSWI seems to be readily introduced in clinical practice. There was no difference in survival between our initial cases and later cases. Late diagnosis and prolonged wound therapy were identified as predictors for late mortality.     

Earlier recovery with beating-heart surgery: a comparison of 300 patients undergoing conventional versus off-pump coronary artery bypass graft surgery

OBJECTIVE: To compare outcomes and cost of off-pump coronary artery bypass (OP-CAB) surgery versus cardiopulmonary bypass-assisted coronary artery bypass graft (CABG) surgery. DESIGN: Retrospective review. SETTING: A tertiary care university teaching hospital. PARTICIPANTS: Patients (n = 300) undergoing isolated CABG surgery performed by a single surgeon between July 1998 and February 2000. INTERVENTIONS: Two groups of patients were compared: 150 consecutive patients undergoing OP-CAB surgery and a matched cohort of 150 consecutive patients undergoing conventional CABG surgery. MEASUREMENTS AND MAIN RESULTS: The 2 groups were evenly matched in terms of age and incidence of diabetes, hypertension, peripheral vascular disease, left main disease, prior strokes, congestive heart failure, and recent infarctions. OP-CAB procedures required 3.3 grafts per patient versus 3.8 grafts per patient required for CABG surgery (p = 0.02). Overall mortality was 2.0% (1.3% in the OP-CAB surgery group v 2.7 % in the CABG surgery group; p = NS). Extubation times (6.6 hours v 9.5 hours; p = 0.003), surgical intensive care unit length of stay (39 hours v 49 hours; p = 0.03), and hospital length of stay (6.1 days v 7.0 days; p = 0.04) were all significantly shorter for the OP-CAB surgery group. The combined aggregate endpoints of death and major morbidity were significantly less in the OP-CAB surgery group (5.3% v 12.7%; p = 0.02). CONCLUSION: OP-CAB surgery is associated with low morbidity and mortality and accelerated recovery compared with conventional CABG surgery. OP-CAB surgery may represent the ideal revascularization strategy for patients at high risk for undergoing cardiopulmonary bypass.     

Risk factors and treatment of deep sternal wound infection after cardiac operation.

OBJECTIVE: Although deep sternal wound infection (DSWI) after cardiac surgery is infrequent, its consequences are serious. The purposes of this study were to define the risk factors, and to establish the best surgical treatment for DSWI. METHODS: Retrospective analysis for 863 patients who underwent cardiac surgery was performed. The patients were divided into the DSWI group (n=17) and the non-infection group (n=846). Preoperative, perioperative, and postoperative variables were compared between the two groups using univariate and multivariate logistic regression analysis. The modality of treatment for DSWI was also analyzed. RESULTS: The incidence of DSWI was 1.97%. Independent predictors for DSWI were concomitant coronary artery bypass grafting (CABG) with valve or aortic surgery [odds ratio, 4.1; 95% confidence interval, (1.1, 15.1)] and postoperative use of intraaortic balloon pumping [4.4, (1.6, 12.3)]. An independent predictor in isolated CABG patients was emergency operation [10.9, (2.7, 44.7)]. Four of 17 patients died. Methicillin-resistant Staphylococcus aureus (MRSA) was cultured from 10 (58.8%) patients, and all four of the deceased subjects died of its infection. Seventeen patients were treated by debridement, primary closure, and the addition of an omentum or muscle flap if necessary. CONCLUSIONS: Patients in poor perioperative condition are at high risk for the development of this infection. It was difficult to establish the best treatment, owing to the small series of this study. Mortality and morbidity of DSWI due to MRSA was high.     

Eliminating the diabetic disadvantage: the Portland Diabetic Project

The Portland Diabetic Project is an ongoing prospective study of 5534 diabetic cardiac surgery patients that elucidates the effects of hyperglycemia, and its subsequent reduction with continuous insulin infusions (CII), on in-hospital outcomes. Increasing glucose levels were found to be directly associated with increasing rates of death, deep sternal wound infections (DSWI), length of stay (LOS), and hospital costs. In separate multivariable analyses, hyperglycemia was found to be independently predictive of mortality (P < 0.0001), DSWI (P = 0.0001), and LOS (P < 0.002). Conversely, CII, designed to achieve predetermined target glucose levels, independently reduced the risks of death and DSWI by 65% and 63%, respectively (P < 0.001 for both). Target glucose levels <150 mg/dL and a 3-day postoperative duration of CII therapy are both important variables that determine the impact of the CII therapy on improved outcomes. Perioperative hyperglycemia in cardiac surgery patients adversely alters mortality, LOS, and infection rates. CII eliminate the increased risks of these complications previously seen in diabetic patients. CII protocols are the standard-of-care for glycometabolic control in cardiac surgery patients.     

Gender-related differences in morbidity and mortality during combined valve and coronary surgery

BACKGROUND: Gender-related differences in morbidity and mortality are well described for coronary artery bypass grafting but are not well understood for combined valve and bypass surgery. METHODS: We reviewed retrospectively the morbidity and mortality of 1570 consecutive patients who underwent combined valve and bypass procedures at the Toronto General Hospital between January 1990 and October 2000. RESULTS: There were 1073 men (68%) and 497 women (32%). The mean ages (+/- 1 SD) of women and men were 69 +/- 9 and 68 +/- 9 years, respectively (P =.02). Of the 1570 total patients, 973 patients (62%) underwent aortic valve and coronary bypass surgery, 481 patients (31%) had mitral valve and coronary bypass operations, and 116 (7%) patients had double or triple valve and coronary bypass operations. Preoperative hypertension (P =.002), diabetes (P =.001), and atrial fibrillation (P =.001) were seen more frequently in women. Body surface area was significantly lower in women (P =.0001). At presentation, more women were in congestive heart failure (69% vs 58%, P =.001) and in New York Heart Association functional class III or IV (25% vs 19%, P =.001). Although there was no difference in the number of women with three or more diseased vessels (32% vs 38%), only 35% of women received three or more grafts compared with 44% of men (P =.001). The use of left internal thoracic grafts, although uncommon in the whole study population (36%), was less common in women than in men (26% vs 41%, P =.001). Multivariable logistic analyses for morbidity and mortality showed female gender to be an independent risk factor. Mitral valve replacement, age, left ventricular dysfunction, New York Heart Association classes III and IV, and association of tricuspid valve disease, diabetes, peripheral vascular disease, and preoperative renal failure were found to be independent risk factors for mortality. CONCLUSION: Female gender is an independent risk factor for combined morbidity and mortality during and after combined valve and coronary bypass surgery. As with isolated coronary artery bypass grafting, women undergoing combined procedures have more premorbid conditions, are more often in heart failure, had an equal incidence of triple vessel disease but received fewer grafts than men, and, therefore, were more frequently incompletely revascularized.     

Influence of diabetes mellitus on early and late outcome after coronary artery bypass grafting.

BACKGROUND: Diabetes mellitus is an established independent risk factor for significant morbidity and mortality after coronary artery bypass grafting. METHODS: The impact of diabetes on short- and longterm follow-up after coronary artery bypass grafting was studied by comparing the outcomes between 9,920 patients without diabetes mellitus and 2,278 patients with diabetes from 1978 to 1993. RESULTS: Compared with nondiabetic patients, the group with diabetes was older (62+/-10 years versus 60+/-10 years), comprised more women (31% versus 19%), had a greater incidence of hypertension (61% versus 44%) and previous myocardial infarction (51% versus 48%), had class III-IV angina more commonly (69% versus 63%), showed a higher incidence of congestive heart failure (11% versus 5%) or triple-vessel or left main disease (60% versus 50%), and had lower ejection fractions (0.54 versus 0.57) (all, p< or =0.05). Diabetic patients had a higher incidence of postoperative death (3.9% versus 1.6%) and stroke (2.9% versus 1.4%) (both, p< or =0.05), but not Q wave myocardial infarction (1.8% versus 2.9%). Diabetics had lower survival (5 years, 78% versus 88%; 10 years, 50% versus 71%; both, p< or =0.05) and lower freedom from percutaneous transluminal coronary angioplasty (5 years, 95% versus 96%; 10 years, 83% versus 86%; latter, p< or =0.05), but diabetics did not have lower freedom from either myocardial infarction (5-years, 92% versus 92%; 10-years, 80% versus 84%) or additional coronary artery bypass grafting (5-years, 98% versus 99%; 10-years, 90% versus 91%). Multivariate correlates of long-term mortality were diabetes, older age, reduced ejection fraction, hypertension, congestive heart failure, number of vessels diseased, and urgent or emergent operation. CONCLUSIONS: Diabetics have a worse hospital and longterm outcome after coronary artery bypass grafting. The increased risk in such patients can only partially be explained by other demographic characteristics.     

Sternal wound infections and use of internal mammary artery grafts

Previous studies have provided conflicting evidence as to whether an increased risk of mediastinitis is associated with use of the internal mammary artery as a coronary bypass graft. In this study the effects of internal mammary artery grafts on wound complications were analyzed in a prospective, nonrandomized fashion. At New York University Medical Center from January 1985 through May 1988, 2356 patients underwent isolated coronary revascularization. Among these patients 1394 received one or more internal mammary artery grafts (group I) and 962 had vein grafts only (group II). Group I had a mean age of 59.5 years versus 67.7 years in group II; diabetes was equally present in both groups (22.7% versus 24.7%). Operative mortality rate was 1.3% in group I and 5.6% in group II. Sternal infection was significantly more prevalent in group I (2.2%, 31/1394) than in group II (0.8%, 8/962). Multivariate analysis revealed that aortic crossclamp time, use of a single internal mammary artery graft, use of a double mammary graft, and diabetes were associated with increased risk of sternal infection. The use of bilateral internal mammary artery grafting doubled the odds ratio of the risk compared with use of a single mammary graft, and the combination of diabetes and double internal mammary artery grafts increased the odds ratio 13.9-fold. Patients with an internal mammary artery graft who had sternal infection had a longer period of hospitalization than patients without a mammary artery graft who had sternal infection. We conclude that the risk of sternal infection is increased by the use of an internal mammary artery graft, especially use of double mammary grafts in the presence of diabetes.     

Does bilateral internal mammary artery grafting increase surgical risk?

The risk of bilateral internal mammary artery grafting was studied in three groups of patients who were computer matched for recognized risk factors: year of operation, age, gender, extent of coronary artery disease, left ventricular function, completeness of myocardial revascularization, and history of congestive heart failure. The patient groups differed in the fact that they received veins only, one internal mammary artery graft, or two internal mammary artery grafts. The operative mortality rates for these three groups were 1.8%, 0.3%, and 0.9%, respectively (no significant difference). Analysis of perioperative morbidity demonstrated no significant differences except for a slight increase in transfusion requirements in the group receiving two internal mammary artery grafts (p = 0.04). None of the patients with only vein grafts had wound complications. One patient in the group with one internal mammary artery graft had a wound complication (0.03%). Eight patients receiving two internal mammary artery grafts had wound complications (2.4%) (p = 0.002). The prevalence of wound complications in patients with diabetes mellitus was 5.7% and in those without diabetes mellitus, 0.3% (p = 0.01). The prevalence of wound complications in patients less than 60 years of age was 0.2%, in patients in their 60s, 1.6%, and in patients older than 70, 3.1% (p = 0.01). Multivariate logistic regression analysis identified diabetes mellitus and age and not bilateral internal mammary artery grafting as risk factors for wound complications. We conclude that bilateral internal mammary artery grafting does not increase surgical mortality and increases surgical morbidity by a slight increase in the mean transfusion requirement.