Late outcomes after radial artery versus saphenous vein grafting during reoperative coronary artery bypass surgery.

OBJECTIVE: We investigated whether use of radial artery versus saphenous vein grafts during coronary artery bypass grafting reoperations is associated with a significant long-term survival benefit. METHODS: We reviewed a series of 347 consecutive coronary artery bypass grafting reoperations (1996-2007; 270 [78%] male patients; age, 65.3 +/- 9.2 years). Internal thoracic artery grafts were used in 248 (71%) patients at the time of the first coronary artery bypass grafting operation and in 154 (44%) patients at reoperation. Patients were grouped based on whether a functional radial artery graft was present after coronary artery bypass grafting reoperation (radial artery cohort, n = 203 [59%]) or not (saphenous vein cohort, n = 144 [41%]). Median time to reoperation was similar for the radial artery (10.3 years) and saphenous vein (10.1 years) cohorts (P = .55). Angiographic data were used to ascertain the number and type of grafts that remained functional from initial coronary artery bypass grafting. Survival data (< or = 12 years) were time segmented based on multiphase hazard modeling at 90 days, and late survival was then analyzed by using proportional hazard Cox regression, with risk adjustment based on a radial artery-use propensity score computed from 48 covariates, including time to reoperation, month of surgical intervention, and total arterial and vein grafts after reoperation. Propensity-matched and propensity quintile comparisons were also done. RESULTS: Follow-up was similar for the radial artery versus saphenous vein cohorts (5.7 +/- 3.4 vs 5.8 +/- 4.0 years, P = .86), and 112 (50 in the radial artery and 62 in the saphenous vein cohorts) deaths were documented. Early mortality (< or = 90 days) did not differ for the radial artery (7.4%) and saphenous vein (12.5%) cohorts (P = .14). Unadjusted late outcomes were superior for the radial artery versus saphenous vein cohorts, with survival of 97.3% versus 92.9%, 84.9% versus 77.2%, and 74.1% versus 60.3% at 1, 5, and 10 years, respectively. Propensity-adjusted radial artery survival was superior, with a hazard ratio of 0.58 (P = .04), and this result was confirmed in a propensity-matched comparison. CONCLUSIONS: We conclude that the use of radial artery as opposed to saphenous vein grafting for reoperative coronary artery bypass grafting, either with or without concomitant internal thoracic artery grafts, is associated with a substantial improvement in late survival. This benefit is likely derived from the increased overall number of arterial grafts.

The effect of diabetic medications on creatine kinase-myocardial band levels in patients undergoing coronary artery bypass surgery.

Ischemic preconditioning has been shown to attenuate the rise in creatine kinase-myocardial band levels that occur with coronary artery bypass surgery (CABG). Recently, concerns have been raised that some sulfonylureas particularly glibenclamide may block ischemic preconditioning. The purpose of this study was to determine the effect of various diabetic medicines on creatine kinase-myocardial band levels after CABG. In this retrospective study of 799 patients undergoing CABG, patients continued their routine diabetic medicines up to the day of surgery. Intra-operatively and postoperatively, tight glycemic control was maintained with an insulin infusion. Anesthesia was maintained with isoflurane supplemented by fentanyl. Creatine kinase-myocardial band levels were determined the day after surgery at 05:00 h and the mean levels compared between diabetics and non-diabetics and further compared by type of diabetic medicine. After univariable comparisons, linear regression was used to determine the statistically significant predictors of creatine kinase-myocardial band levels. After correction for other factors, none of the diabetic medicines was a statistically significant predictor of creatine kinase-myocardial band levels. We found that the use of glibenclamide or other diabetic medications had no effect on creatine kinase-myocardial band levels the morning after patients underwent CABG.

Sequential radial artery grafts for multivessel coronary artery bypass graft surgery: 10-year survival and angiography results.

BACKGROUND: Increasing the number of arterial grafts for coronary artery bypass grafting (CABG) has been linked to improved late survival. Currently, it is not known if these long-term benefits are also true when sequential radial artery (RA) grafts are the primary means to maximizing arterial revascularization. METHODS: We compared late survival of 532 consecutive patients receiving sequential RA grafts (sequential RA group: 438 men; 462 with three-vessel disease) with that of a 4,131 contemporaneous internal thoracic artery (ITA) with saphenous vein (SV) multivessel CABG cohort (conventional group). Graft failure rates were determined from symptom-driven repeat angiography films in 122 sequential RA patients performed 2 to 4,317 days after surgery. Median survival sequential RA follow-up was 5.3 years (range, 0.5 to 12.3). RESULTS: The sequential RA patients received a total of 1,181 RA grafts (538 sequential [30 triple] and 75 single) along with 636 SV and 533 ITA. Overall RA graft failure (80 of 272; 29%) was intermediate to that for ITA (7 of 121; 5.8%; p < 0.001) and vein (54 of 133, 41.6%; p = 0.032) grafts. Sequential versus nonsequential RA failure did not differ (77 of 252 [31%] versus 3 of 20 [15%]; p = 0.202), while failure of the proximal (36 of 123; 29%) and distal (40 of 129; 31%) components of sequential RA grafts were essentially identical. A total of 69 deaths (6 operative; 1.1%) have occurred in the sequential RA cohort. Unadjusted 10-year sequential RA cohort survival was 76.2% overall, and 79.0% for the 454 primary isolated CABG subgroup. The risk-adjusted 10-year survival using a logit propensity score was substantially better for the sequential RA cohort versus the conventional CABG cohort (risk ratio [95% confidence interval] 0.61 [0.44 to 0.85]; p = 0.003). CONCLUSIONS: Sequential RA grafting is a safe method for maximizing arterial revascularization and is associated with excellent 10-year survival that seems to be superior to conventional or ITA/SV CABG results. Also, the similar proximal and distal sequential RA patency mitigates concerns of a clinically significant effect of increased vasoreactivity of distal segments of RA conduits.

The effect on long-term survival of erythrocyte transfusion given for cardiac valve operations.

BACKGROUND: Studies in patients undergoing coronary artery bypass grafting (CABG) have shown an increased long-term mortality rates associated with perioperative blood transfusions. However, some studies in other patient populations have shown no effect on death or even a lowered mortality rate in patients receiving blood transfusions, which suggests that the effects of blood transfusion may be disease-dependent. METHODS: Data of all patients who underwent valve operations with or without associated CABG between October 2, 1991, and November 14, 2007, were obtained from the department's database and analyzed using logistic regression for 30-day and Cox models for long-term mortality to determine the effects of transfusion on death. To control for the potential interaction between transfusion and complications and sicker patients being more likely to receive blood, we separately analyzed the data for the different valve populations and used propensity analysis to control for sicker patients being more likely to receive blood. RESULTS: Of 1823 patients who underwent valve operations, the operation was isolated in 993 and combined with CABG in 830. By 30 days, 125 patients (6.9%) had died, and 717 (39%) were dead at follow-up. After controlling for type of operation and factors that influenced the transfusion decision, transfusion was associated with increased death only in patients who had combined valve and CABG, and not in isolated valve operations. CONCLUSIONS: Transfusion had no effect on the mortality rate after isolated valve operations but was associated with increased mortality when valve operations were combined with CABG.

Late results of conventional versus all-arterial revascularization based on internal thoracic and radial artery grafting.

BACKGROUND: Use of one or more arterial grafts to revascularize two-vessel and three-vessel coronary artery disease has been shown to improve coronary artery bypass graft surgery (CABG) survival. Yet, the presumed long-term survival benefits of all-arterial CABG have not been quantified. METHODS: We compared propensity-adjusted 12-year survival in two contemporaneous multivessel primary CABG cohorts with all patients receiving 2 or more grafts: (1) all-arterial cohort (n = 612; 297 three-vessel disease [49%]); and (2) single internal thoracic artery (ITA) plus saphenous vein (SV) cohort (n = 4,131; 3,187 three-vessel disease [77%]). RESULTS: Early (30-day) deaths were similar for the all-arterial and ITA/SV cohorts (8 [1.30%] versus 69 [1.67%]) whereas late mortality was substantially greater for the ITA/SV cohort (85 [13.9%] versus 1,216 [29.4%]; p < 0.0001). The risk-adjusted 12-year survival was significantly better for all-arterial (with a risk ratio [RR] = 0.60; 95% confidence interval [CI]: 0.48 to 0.75; p < 0.001), but this benefit was true only for three-vessel disease (RR = 0.58; 95% CI: 0.43 to 0.78; p < 0.001) and not for two-vessel disease (RR = 0.97; 95% CI: 0.66 to 1.43; p = 0.89). The all-arterial survival benefit was also true for varying risk subcohorts: no diabetes mellitus (RR = 0.50; 95% CI: 0.37 to 0.69), diabetes mellitus (RR = 0.77; 95% CI: 0.56 to 1.07), ejection fraction 40% or greater (RR = 0.60; 95% CI: 0.45 to 0.78), and ejection fraction less than 40% (RR = 0.62; 95% CI: 0.40 to 0.98). Lastly, the multivariate analysis indicated a strong long-term effect of completeness of revascularization, particularly for all-arterial patients, so that compared with patients with two grafts, survival was significantly better when three grafts (RR = 0.54; 95% CI: 0.33 to 0.87) or four grafts (RR = 0.40; 95% CI: 0.21 to 0.76) were completed. CONCLUSIONS: All-arterial revascularization is associated with significantly better 12-year survival compared with the standard single ITA with saphenous vein CABG operation, in particular for triple-vessel disease patients. The completeness of revascularization of the underlying coronary disease is critical for maximizing the long-term benefits of arterial-only grafting.

The prevalence of elevated hemoglobin A1c in patients undergoing coronary artery bypass surgery.

BACKGROUND: Diabetes mellitus has become a major health issue in the United States and contributes to morbidity and mortality from coronary artery disease. Despite lifestyle changes and medications that have been shown to decrease complications and death, many persons have poor glycemic control. The purpose of this study is to determine the prevalence of elevated Hemoglobin A1c levels, a marker of glycemic control in patients presenting for coronary artery bypass surgery, and to determine if risk factors for diabetes mellitus could identify those patients with an elevated hemoglobin A1c. METHODS: All patients undergoing coronary artery bypass surgery had hemoglobin A1c levels determined immediately preoperatively. Proportions were used to describe the number of patients with elevated levels. Linear regression and receiver operator characteristic curves were used to evaluate the accuracy of risk factors to identify patients with elevated levels. RESULTS: 83 of 87 (95%) diabetic patients had elevated A1c levels (>or= 6.0%), with 55 of 87 (63%) having inadequate control - A1c levels >or= 7.0. 93 of 163 (57%) non-diabetic patients had elevated A1c levels (>or= 6.0%), with 19 (12%) having levels >or= 7.0%. Risk factors for diabetes mellitus poorly predicted which patient had elevated A1c levels. CONCLUSION: The prevalence of elevated hemoglobin levels in patients undergoing coronary artery bypass surgery is high and routine measurement should be done to permit institution of lifestyle modifications and medication changes that decrease complications and death from diabetes mellitus.

Does radial use as a second arterial conduit for coronary artery bypass grafting improve long-term outcomes in diabetics?

OBJECTIVES: The evidence supporting the survival benefit of multiple arterial grafts in the general coronary bypass surgery (CABG) population is compelling. Alternatively, results of studies comparing 2 versus 1 internal thoracic artery (ITA) grafts in diabetics have reported conflicting survival data. The use of radial versus ITA as the second arterial conduit has not been studied. METHODS: We obtained complete death follow-up in 1516 consecutive diabetic [64+/-10 years (mean+/-SD). Insulin/no insulin: There were 540 (36%)/976 (64%)] primary isolated CABG patients all with >or=1 ITA grafts. The series included 626 ITA/radial (41%) and 890 ITA/vein (59%) patients. Using separate radial-use propensity models, we matched one-to-one 475 (76%) ITA/radial to 475 (53%) unique ITA/vein patients; each including 166 insulin and 309 no insulin patients. RESULTS: Unadjusted survival was markedly better for (1) ITA/radial (94.3%, 86.7% and 70.4% at 1, 5 and 10 years, respectively) versus ITA/vein (91.8%, 74.5% and 53.8%; p<0.0001) and (2) for no insulin (94.2%, 82.8% and 65.5%) versus insulin (90.4%, 73.1% and 49.2%; p<0.0001). In matched patients, 11-year Kaplan-Meier analysis showed essentially identical ITA/radial and ITA/vein survival for all diabetics combined (p=0.53; log rank) and for the no insulin (p=0.76) cohort. Lastly, a trend for better ITA/radial survival in insulin dependent diabetics after the second postoperative year did not reach significance (p=0.13). CONCLUSIONS: Using radial as a second arterial conduit as opposed to vein grafting did not confer a survival benefit in diabetics. This unexpected result is perhaps related to relatively diminished radial graft patency and/or the augmented radial vasoreactivity characteristic of diabetics. These findings indicate that the radial survival advantage demonstrated in the general CABG population lies primarily in non-diabetics in whom this advantage may be underestimated.

Postoperative analgesia with ketorolac is associated with decreased mortality after isolated coronary artery bypass graft surgery in patients already receiving aspirin: a propensity-matched study.

OBJECTIVE: This study was designed to determine the effect of ketorolac on mortality after cardiac surgery. DESIGN: A retrospective multivariable analysis with propensity matching and propensity scoring. SETTING: A tertiary care university-affiliated medical center. PARTICIPANT: Eleven hundred eighty-six patients undergoing isolated coronary artery bypass surgery. MAIN RESULTS: Between January 1, 2002, and November 1, 2004, 168 patients undergoing isolated coronary artery bypass surgery received ketorolac, whereas 1,018 patients did not. There were 2 deaths (1%) in the ketorolac group compared with 104 (10%) in the nonketorolac group (p < 0.001). Within 90 days of surgery, there was 1 death (1%) in the ketorolac group compared with 51 (5%) in the nonketorolac group (p = 0.01). By Cox modeling, ketorolac use was associated with a 7-fold lower risk of death (p = 0.02). In the patients who survived at least 90 days, there was 1 death (1%) in the ketorolac group compared with 53 (5%) in the nonketorolac group (p = 0.01). By Cox modeling, ketorolac use was associated with a 2.4-fold lower risk of death (p = 0.03) in the late hazard period. In the propensity-matched groups, Kaplan-Meier survival was better in patients who received ketorolac (p = 0.02). CONCLUSION: The use of ketorolac was associated with a statistically significant decrease in mortality at follow-up.

Survival and graft patency after coronary artery bypass grafting with coronary endarterectomy: role of arterial versus vein conduits.

BACKGROUND: Coronary artery bypass grafting with concomitant coronary endarterectomy (CABG/CE) is used in patients with severe coronary atherosclerosis to revascularize otherwise ungraftable targets. This study investigates the efficacy of arterial versus vein grafting for CABG/CE surgery. METHODS: We reviewed our experience in 288 CABG/CE patients (63 +/- 10 years, 207 men). A total of 1,056 grafts (275 internal thoracic artery [ITA] [26%]; 221 radial [21%], 560 vein [53%]) were constructed including 325 (31%) placed to CE targets. RESULTS: Eighteen of 288 patients died in-hospital (6.3%). Unadjusted one-year and five-year survival for the 270 discharged patients was 95.2% and 83.0%, respectively. Survival (0 to 7 years) was significantly better for patients with radial (n = 154) versus no-radial (n = 134) artery grafting (p = 0.021). Multivariate Cox regression analysis associated increased number of arterial grafts (hazard ratio [HR] = 0.64 [0.44 to 0.92]; HR [95% confidence interval]) to improved survival, while RCA endarterectomy (HR = 1.8 1.0 3.3; p = 0.054) was associated with worse survival. Repeat angiography (495 days [median]) in 68 patients encompassed 78 CE (38 vein, 24 ITA, and 16 radial) and 162 non-CE (84 vein, 40 ITA, and 38 radial) grafts. Graft failure was similar (p = 0.37) for radial (10 of 54 [19%]) and ITA (7 of 64 [11%]), and worst for vein (50 of 122 [41%]; p < 0.001). For CE targets, graft failure was worse for vein (55% vs 35%; p = 0.05) and unchanged for arterial (13% vs 15%; p = 0.88) grafts. CONCLUSIONS: Combined CABG/CE is associated with good long-term outcomes. Increased arterial grafting achieved by radial artery utilization confers a survival benefit in this high-risk population. The latter is probably derived from superior radial versus vein graft patency.

Obesity and risk of new-onset atrial fibrillation after cardiac surgery.

BACKGROUND: New-onset postoperative atrial fibrillation (AF) is a common complication of cardiac surgery that has substantial effects on outcomes. In the general (nonsurgical) adult population, AF has been linked to increasing obesity, which correlates with left atrial enlargement. It is not known whether postoperative AF is similarly linked to obesity. METHODS AND RESULTS: This was a retrospective analysis of the incidence of AF in terms of body mass index (BMI). A total of 8051 consecutive cardiac surgery patients (1994 to 2004; mean age 64 [SD 11] years; 5372 men [67%]) who were free of any history of preoperative AF or flutter were included in the analysis. This series included 3164 obese patients (39%; median age 62 years) and 4887 nonobese patients (61%; median age 66 years), who were further divided on the basis of BMI (kg/m2) into 6 groups: BMI <22 kg/m2, 22< or =BMI< or =25 kg/m2 (normal), 25 or =30 kg/m2 (overweight), 30 or =35 kg/m2 (obese I), 35 or =40 kg/m2 (obese II), and BMI >40 kg/m2 (obese III). Unadjusted AF incidence was similar in obese and nonobese patients (n=742 [23.5%] versus n=1068 [21.9%], respectively; P=0.099). Covariate-adjusted ORs for AF were systematically greater for larger patients than for patients in the normal group (adjusted OR [95% CI]=1.18 [1.00 to 1.40], 1.36 [1.14 to 1.63], 1.69 [1.35 to 2.11], and 2.39 [1.81 to 3.17] for overweight, obese I, obese II, and obese III, respectively). Other AF predictors included age (adjusted OR=1.52 [95% CI 1.46 to 1.58] per 10 years), mitral valve surgery (adjusted OR=2.42 [95% CI 1.92 to 3.06]), aortic valve surgery (adjusted OR=1.79 [95% CI 1.45 to 2.22]), chronic obstructive pulmonary disease (adjusted OR=1.28 [95% CI 1.12 to 1.46]), male gender (adjusted OR=1.24 [95% CI 1.10 to 1.40]), preoperative beta-blocker use (adjusted OR=1.17 [95% CI 1.05 to 1.32]), vascular disease (adjusted OR=1.18 [95% CI 1.05 to 1.32]), white race (adjusted OR=1.33 [95% CI 1.07 to 1.66]), history of arrhythmia other than AF/flutter (adjusted OR=0.80 [95% CI 0.68 to 0.96]), ejection fraction <40% (adjusted OR=1.16 [95% CI 1.03 to 1.31]), left main disease (adjusted OR=1.15 [95% CI 1.00 to 1.32]), and off-pump surgery (adjusted OR=0.61 [95% CI 0.44 to 0.83]). The obesity-AF association was confirmed in 4 1-to-1 propensity-matched obese versus nonobese comparisons and in 2 separate derivation/validation subcohort analyses. CONCLUSIONS: Obesity is an important determinant of new-onset AF after cardiac surgery. Future postoperative AF risk models should incorporate BMI or obesity levels. Studies examining the efficacy of AF-minimizing prophylactic interventions in high-BMI patients, particularly in the elderly, may be warranted.

Operative and late coronary artery bypass grafting outcomes in matched African-American versus Caucasian patients: evidence of a late survival-Medicaid association.

OBJECTIVES: This study sought to determine whether African-American versus Caucasian race is a determinant of early or late coronary artery bypass surgery (CABG) outcomes. BACKGROUND: African Americans are referred to CABG less frequently than Caucasians and Medicaid coverage is disproportionately common among those who are referred. How these factors affect the relative early and late CABG outcomes in these groups is incompletely elucidated. METHODS: A retrospective cohort comparison of operative and 12-year outcomes for 304 African-American and 6,073 Caucasian consecutive patients who underwent isolated CABG (1991 to 2003) at an urban community hospital was used. Results were further confirmed in propensity-matched subgroups (n = 301 each). RESULTS: African Americans were younger (62 vs. 64 years, median), more were female (46% vs. 30%), more were on Medicaid (29% vs. 6.3%) and had more comorbidities. These differences were eliminated after matching. A total of 161 operative and 1,080 late deaths have been documented. Operative mortality was similar (African American versus Caucasian: 3.0% vs. 2.5%; p = 0.81). Unadjusted Kaplan-Meier survival at 1, 5, and 10 years (93.4%, 80.3%, and 66.1% vs. 94.8%, 86.5%, and 71.7%) was worse in African Americans (hazard ratio [HR] = 1.38; p = 0.004), but similar for matched groups (HR = 1.03; p = 0.97). After risk adjustment, race did not predict operative (odds ratio = 1.17; p = 0.69) or late (HR = 1.15; p = 0.28) mortality. However, Medicaid status (HR = 1.54; p < 0.005) predicted worse survival, which was verified in a case-matched Medicaid (n = 469) versus non-Medicaid analysis. The latter showed that in younger Medicaid patients without companion Medicare coverage, late mortality was nearly doubled (HR = 1.96; p = 0.003) with systematically increasing death hazard after the second year. CONCLUSIONS: African-American race per se is not associated with worse operative or late outcomes underscoring that CABG should be based on clinical characteristics only. Alternatively, Medicaid status, which is more prevalent among African Americans, is associated with worse late survival, especially in non-Medicare patients. Studies are needed to elucidate this late Medicaid-CABG outcome association.

Role of hemodilutional anemia and transfusion during cardiopulmonary bypass in renal injury after coronary revascularization: implications on operative outcome.

OBJECTIVE: Acute renal injury and failure (ARF) after cardiopulmonary bypass (CPB) has been linked to low on-pump hematocrit (hematocrit). We aimed to 1) elucidate if and how this relation is modulated by the duration of CPB (TCPB) and on-pump packed red blood cell transfusions and 2) to quantify the impact of post-CPB renal injury on operational outcome and resource utilization. DESIGN: Retrospective review. SETTING: A Northwest Ohio community hospital. PATIENTS: Adult coronary artery bypass surgery patients with CPB but no preoperative renal failure. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: We quantified post-CPB renal injury via 1) the peak postoperative change in serum creatinine (Cr) level relative to pre-CPB values (%DeltaCr) and 2) ARF, defined as the coincidence of post-CPB Cr > or =2.1 mg/dL and >2 times pre-CPB Cr. The separate effects of lowest hematocrit, intraoperative packed RBC transfusions, and TCPB on %DeltaCr and ARF were derived via multivariate regression, overlapping quintile subgroup analyses, and propensity matching. Lowest hematocrit (22.0% +/- 4.6% sd), TCPB (94 +/- 35 mins), and pre-CPB Cr (1.01 +/- 0.23 mg/dL) varied widely. %DeltaCr varied substantially (24 +/- 57%), and ARF was documented in 89 patients (5.1%). Both %DeltaCr (p < .001) and ARF (p < .001) exhibited sigmoidal dose-dependent associations to lowest hematocrit that were 1) modulated by TCPB such that the renal injury was exacerbated as TCPB increased, 2) worse in patients with relatively elevated pre-CPB Cr (> or =1.2 mg/dL), and 3) worse with intraoperative packed red blood cell transfusions (n = 385; 21.9%), in comparison with patients at similar lowest hematocrit. Operative mortality (p < .01) and hospital stays (p < .001) were increased systematically and significantly as a function of increased post-CPB renal injury. CONCLUSIONS: CPB hemodilution to hematocrit <24% is associated with a systematically increased likelihood of renal injury (including ARF) and consequently worse operative outcomes. This effect is exacerbated when CPB is prolonged with intraoperative packed red blood cell transfusions and in patients with borderline renal function. Our data add to the concerns regarding the safety of currently accepted CPB practice guidelines.

The association of elevated creatine kinase-myocardial band on mortality after coronary artery bypass grafting surgery is time and magnitude limited.

OBJECTIVE: The joint European Society of Cardiology and American College of Cardiology consensus statement on myocardial necrosis after revascularization stated that any amount of myocardial necrosis as detected by cardiac enzymes should be labeled a myocardial infarct. However, it also stated that more data collection is necessary to better interpret the elevation of cardiac enzymes after coronary artery bypass grafting. We sought to determine if a single postoperative value of creatine kinase-myocardial band could be used as a risk factor to help predict mortality after coronary artery bypass surgery. METHODS: A retrospective analysis of prospectively collected data on 1161 patients undergoing first-time, isolated coronary artery bypass surgery utilizing normothermic cardiopulmonary bypass was conducted. Creatine kinase-myocardial band was measured the morning after surgery. Binary logistic regression, Cox proportional hazard models, and overlapping quintiles were used to illuminate the association between creatine kinase-myocardial band elevation and mortality after coronary artery bypass surgery. RESULTS: We found a threshold value of creatine kinase-myocardial band, 40 ng/mL, above which elevations were associated with increased death rates. This association held after adjustment for other factors known to contribute to postoperative mortality. However, after 1 year, there was no longer a statistically significant higher mortality associated with elevated creatinine kinase-myocardial band > 40 ng/mL. CONCLUSION: Elevation of creatine kinase-myocardial band the morning after surgery above a threshold 40 ng/mL is associated with an increased risk of mortality.

Is hospital procedure volume a reliable marker of quality for coronary artery bypass surgery? A comparison of risk and propensity adjusted operative and midterm outcomes.

BACKGROUND: Worse operative mortality has been reported for hospitals with low versus high coronary artery bypass grafting surgery volumes. Despite a lack of comparisons beyond the early postoperative period and evidence of surgeon-volume confounding, some have suggested that regionalization of coronary artery bypass grafting in favor of high volume institutions is warranted. METHODS: We retrospectively compared operative mortality and 3-year survival in coronary artery bypass grafting patients (2001 to 2003) at a low-volume hospital (n = 504; 160 per year [median]) versus a high-volume hospital (n = 1,410; 487 per year) served by the same high-volume surgeon team. Covariate risk adjustment was done via multivariate and propensity modeling. RESULTS: The two hospital cohorts exhibited multiple demographic and risk factor differences. Unadjusted low-volume hospital vs high-volume hospital operative mortality was similar overall (2.38% vs 2.98%; p = 0.59) with nearly identical Society of Thoracic Surgeons observed-to-expected ratios (0.83 vs 0.82), irrespective of preoperative risk category. Hospital volume did not predict operative mortality (odds ratio, 95% confidence interval = 0.82; p = 0.602). At follow-up, a total of 28 low-volume hospital deaths (5.6%) and 135 high-volume hospital deaths (9.6%) occurred at similar surgery-to-death intervals (p = 0.7). Unadjusted 0 to 3-year survival was significantly worse for high-volume hospitals (risk ratio = 1.59; 1.06 to 2.39; p = 0.026). Yet procedure volume was not independently associated with worse midterm survival after covariate (risk ratio = 1.28; 0.84 to 1.96; p = 0.247) or propensity score (risk ratio = 1.11; 0.72 to 1.71; p = 0.648) adjustment. CONCLUSIONS: Hospital and surgeon volume effects on coronary artery bypass grafting outcomes are interdependent, and therefore hospital coronary artery bypass grafting volume per se is not a reliable marker of quality. Instead, outcome quality markers should rely on thorough risk-adjustment based on detailed clinical databases, possibly including annual and cumulative surgeon volume.

Effects of obesity and small body size on operative and long-term outcomes of coronary artery bypass surgery: a propensity-matched analysis.

BACKGROUND: The effects of body habitus on coronary artery bypass graft surgery (CABG) operative and long-term outcomes are not well defined. We aimed to elucidate the independent effects of small body size and obesity on CABG outcomes. METHODS: Primary isolated CABG patients were grouped based on body surface area (BSA, m2) and body mass index (BMI, kg/m2) as follows: 611 very small (BSA < or = 1.70); 933 slightly small (1.70 < BSA < or = 1.85); 945 moderately obese (32 < BMI < 36); 594 very obese (BMI > or = 36); and 3,018 normal (BSA >1.85; BMI = 22 to 32). Subcohorts of very small (371 pairs, 61%), slightly small (717, 77%), moderately obese (874, 92%), and very obese (516, 87%) patients were propensity-matched to normal. RESULTS: Compared with normal, very small had more transfusions (46% versus 32%; p < 0.001), reoperation for bleeding (3.2% versus 0.3%; p = 0.002), and pulmonary edema (2.4% versus 0.5%; p = 0.033). For slightly small, transfusion (41% versus 29%; p < 0.001) and bleeding (2.5% versus 1.0%; p = 0.04) were increased. For moderately obese, sternal wound infections (1.9% versus 0.8%; p = 0.04) were greater. Complications were most frequent in very obese: reoperation (5.2% versus 1.6%; p < 0.001), sternal wound infections (3.5% versus 0.2%; p < 0.001), pulmonary edema (2.9% versus 1.2%; p = 0.047), renal failure (6.0% versus 2.3%; p = 0.003), atrial fibrillation (20% versus 12%; p = 0.001), gastrointestinal problems (3.7% versus 1.6%; p = 0.032), and postoperative stay (8.0 versus 6.4 days; p = 0.003). When slightly small and very small are considered together, operative mortality was significantly greater (3.22% versus 1.65%; p = 0.026). Both very small (risk ratio [RR] = 1.39; p = 0.044) and very obese (RR = 1.44; p = 0.020) were independent predictors of worse 0- to 12-year mortality. CONCLUSIONS: Large deviations from normal body size in either direction--particularly extreme obesity--are associated with increased postoperative morbidity and worse long-term survival.