Long-Term Survival After Off-Pump Coronary Artery Bypass Grafting.

BACKGROUND: The aim of this study was to compare the long-term survival rates of patients undergoing isolated first-time coronary artery bypass grafting (CABG) by off-pump CABG with the long-term survival rates in patients undergoing CABG using cardioplegic cardiopulmonary bypass techniques. METHODS: All patients undergoing isolated CABG at a single center (Manchester Heart Centre, Manchester, United Kingdom) between 2000 and 2014 were included. Propensity score matching was performed on the basis of on demographic variables. The in-hospital morbidity and long-term all-cause mortality rates for matched patients were compared. RESULTS: A total of 8,055 patients were identified, with a median follow-up of 7.0 years. With patients matched for preoperative patient characteristics, there was no significant difference in long-term survival between cardiopulmonary bypass and off-pump CABG (n = 2,082 each; 11.5 years vs 11.3 years; p = 0.178). In the off-pump CABG group, there were significantly fewer in-hospital cerebrovascular complications (0.5% vs 1.1%; p = 0.017), and mean length of stay was shorter (7.6 days vs 8.1 days; p < 0.0001). Arterial conduit use was significantly higher in the off-pump group, with more right mammary artery grafts (16.3% vs 4.3%; p < 0.0001) and sequential grafts (27.1% vs 13.5%; p < 0.0001). The mean number of grafts was higher in the on-pump group (3.28 ± 0.94 vs 3.10 ± 1.10; p < 0.0001). CONCLUSIONS: Long-term survival after off-pump CABG is not inferior to long-term survival after on-pump CABG despite a lower mean number of grafts. A statistically significant difference in cerebrovascular complications may be related to conduit choice and reduced aortic manipulation.

Effect of risk-adjusted, non-dialysis-dependent renal dysfunction on mortality and morbidity following coronary artery bypass surgery: a multi-centre study.

OBJECTIVE: As little is known about the impact of non-dialysis-dependent renal dysfunction on short- and mid-term outcomes following coronary surgery we have conducted a large multi-centre study comparing patients with no history of renal dysfunction to those with preoperative renal dysfunction. METHODS: Data was prospectively collected on 19,625 consecutive patients undergoing isolated coronary surgery between 1997 and 2003 from four institutions. Sixty-seven patients had a history of dialysis support prior to coronary surgery, and were excluded from the main analysis of the study. The remaining 19,558 patients were divided into two groups based on preoperative serum creatinine level, patients with preoperative renal dysfunction with serum creatinine levels >200 micromol/L without dialysis support and control patients with preoperative serum creatinine levels <200 micromol/L. Case-mix was accounted for by developing a propensity score, which was the probability of belonging to the non-dialysis-dependent renal dysfunction group, and included in the multivariable analyses. RESULTS: There were 19,172 patients with preoperative serum creatinine levels <200 micromol/L and 386 patients with serum creatinine levels >200 micromol/L without dialysis support. The propensity score included sex, body mass index, co-morbidity factors (respiratory disease, diabetes, cerebrovascular disease, hypertension, and hypercholesterolemia), ejection fraction, left main stem stenosis, emergency status, prior cardiac surgery, off-pump surgery, and the logistic EuroSCORE. After adjusting for the propensity score, patients with preoperative non-dialysis-dependent renal dysfunction had significantly higher in-hospital mortality (adjusted odds ratio 3.0, p < 0.001), stroke (adjusted odds ratio 2.0, p = 0.033), atrial arrhythmia (adjusted odds ratio 1.5, p = 0.003), prolonged ventilation (adjusted odds ratio 2.1, p < 0.001), and post-op stay > 6 days (adjusted odds ratio 2.6, p < 0.001). One thousand one hundred and eighty-three (6.1%) deaths occurred during 58,062 patient-years follow-up. After adjusting for the propensity score, the adjusted hazard ratio of mid-term mortality for non-dialysis-dependent renal dysfunction was 2.7 (p < 0.001). CONCLUSIONS: Patients undergoing coronary surgery with non-dialysis-dependent renal dysfunction have significantly increased perioperative morbidity and mortality. Mid-term survival is also significantly reduced at 5-years.

Limitations of additive EuroSCORE for measuring risk stratified mortality in combined coronary and valve surgery.

OBJECTIVE: To study the use of the additive and logistic European System for Cardiac Operative Risk Evaluation (EuroSCORE) to predict mortality following adult combined coronary artery bypass grafting (CABG) and valve surgery. METHODS: Data were collected prospectively, from all four centres providing adult cardiac surgery in the north west of England, on 1769 consecutive patients undergoing combined CABG and valve surgery between April 1997 and March 2002. Observed in-hospital mortality was compared to predicted mortality as determined by both additive and logistic EuroSCORE. RESULTS: Observed mortality for simultaneous CABG and valve surgery was 8.7%, compared to 6.7% (additive) and 9.4% (logistic). Sixty-five percent of patients were classified as high-risk (additive EuroSCORE >5); the observed mortality was 11.5%, compared to 8.1% (additive) and 12.8% (logistic). Discrimination was similar in both systems as measured by the C statistic (additive 0.73, logistic 0.73). CONCLUSIONS: The logistic EuroSCORE is more accurate at predicting mortality in simultaneous CABG and valve surgery, as the additive EuroSCORE significantly under-predicts in this high-risk group.

Coronary surgery in patients with peripheral vascular disease: effect of avoiding cardiopulmonary bypass.

BACKGROUND: An increasing number of patients with peripheral vascular disease are undergoing coronary artery bypass grafting. Such patients have an increased risk of adverse outcomes. Our aim was to quantify the effect of avoiding cardiopulmonary bypass in this group of patients. METHODS: Between April 1997 and March 2002, 3,771 consecutive patients underwent coronary artery bypass grafting performed by five surgeons. Four hundred and twenty-two (11.2%) had peripheral vascular disease and of these, 211 (50%) received off-pump surgery. We used multivariate logistic regression analysis to assess the effect of off-pump surgery on in-hospital mortality and morbidity, while adjusting for treatment selection bias. Treatment selection bias was controlled for by constructing a propensity score, which was the probability of receiving off-pump surgery and included core patient characteristics. The C statistic for this model was 0.8. RESULTS: Off-pump patients were more likely to have preoperative renal dysfunction, previous gastrointestinal surgery, and less extensive disease. The left internal mammary artery was used more in off-pump compared to on-pump cases (90.1% vs 82.9%; p = 0.033). In the univariate analyses, off-pump patients were less likely to have a postoperative stroke (p = 0.007), and had shorter postoperative hospital stays (p < 0.001). However, the incidence of new atrial arrhythmia was higher (p = 0.028). After adjustment for differences in case-mix (propensity score), avoidance of cardiopulmonary bypass was still associated with a significant reduction in postoperative stroke (adjusted odds ratio 0.09 [95% confidence interval 0.02 to 0.50]; p = 0.005), and shorter postoperative hospital stay (p = 0.001). CONCLUSIONS: Off-pump coronary surgery is safe in patients with peripheral vascular disease, with acceptable results. The incidence of postoperative stroke is substantially reduced when avoiding cardiopulmonary bypass in patients with peripheral vascular disease.

Effect of avoiding cardiopulmonary bypass in non-elective coronary artery bypass surgery: a propensity score analysis.

OBJECTIVE: Non-elective coronary artery surgery (emergent/salvage or urgent) carries an increased risk in most risk-stratification models. Off-pump coronary surgery is increasingly used in non-elective cases. We aimed to investigate the effect of avoiding cardiopulmonary bypass on outcomes following non-elective coronary surgery. METHODS: Of the 3771 consecutive coronary artery bypass procedures performed by five surgeons between April 1997 and March 2002, 828 (22%) were non-elective and 417 (50.4%) of these patients had off-pump surgery. Multivariate logistic regression was used to assess the effect of off-pump on in-hospital outcomes, while adjusting for treatment selection bias. Treatment selection bias was controlled for by constructing a propensity score from core patient characteristics, which was the probability of avoiding cardiopulmonary bypass. The C statistic for this model was 0.8. RESULTS: Off-pump patients were more likely to be hypertensive, stable, had less extensive disease and better left ventricular function. The left internal mammary artery was used in 91.8% (n=383) of off-pump patients compared to 79.3% (n=326) of on-pump cases (P<0.001). After adjusting for the propensity score, no difference in in-hospital mortality was observed between off-pump and on-pump (adjusted odds ratio (OR) 0.83 (95% confidence intervals (CI) 0.36-1.93); P=0.667). Off-pump patients were less likely to require intra-aortic balloon pump support (adjusted OR 0.44 (95% CI 0.21-0.96); P=0.039), less likely to have renal failure (adjusted OR 0.44 (95% CI 0.22-0.90); P=0.025), and have shorter lengths of stay (adjusted OR 0.51 (95% CI 0.37-0.70); P<0.001). Other morbidity outcomes were similar in both groups. CONCLUSIONS: In this experience, off-pump coronary surgery in non-elective patients is safe with acceptable results. Non-elective off-pump patients have a significantly reduced incidence of renal failure, and shorter post-operative stays compared to on-pump coronary artery bypass surgery.

Surgeon specific mortality in adult cardiac surgery: comparison between crude and risk stratified data.

OBJECTIVE: As a result of recent failures in clinical governance the government has made a commitment to bring individual surgeons' mortality data into the public domain. We have analysed a database to compare crude mortality after coronary artery bypass surgery with outcomes that were stratified by risk. DESIGN: Retrospective analysis of prospectively collected data. SETTING: All NHS centres in the geographical north west of England that undertake cardiac surgery in adults. PARTICIPANTS: All patients undergoing isolated bypass graft surgery for the first time between April 1999 and March 2002. MAIN OUTCOME MEASURES: Surgeon specific postoperative mortality and predicted mortality by EuroSCORE. RESULTS: 8572 patients were operated on by 23 surgeons. Overall mortality was 1.7%. Observed mortality between surgeons ranged from 0% to 3.7%; predicted mortality ranged from 2% to 3.7%. Eighty five per cent (7286) of the patients had a EuroSCORE of 5 or less; 49% of the deaths were in this lower risk group. A large proportion of the variability in predicted mortality between surgeons was due to a small but differing number of high risk patients. CONCLUSIONS: It is possible to collect risk stratified data on all patients undergoing coronary bypass surgery. For most the predicted mortality is low. The small proportion of high risk patients is responsible for most of the differences in predicted mortality between surgeons. Crude comparisons of death rates can be misleading and may encourage surgeons to practise risk averse behaviour. We recommend a comparison of death rates that is stratified by risk and based on low risk cases as the national benchmark for assessing consultant specific performance.

Off-pump coronary artery bypass surgery does not reduce gastrointestinal complications.

OBJECTIVES: Gastrointestinal (GI) complications following on-pump coronary artery bypass grafting (CABG) are rare, but carry a high mortality rate. Prolonged cardiopulmonary bypass (CPB) has been associated with a higher incidence of such complications. Little is known about the effect of avoiding CPB on GI complications. Our hypothesis was that off-pump CABG might reduce such complications. METHODS: A total of 2327 consecutive cases undergoing isolated CABG between April 1997 and May 2001 were identified from four consultants' practice at the two cardiothoracic centres involved in this study. We performed a multivariable logistic regression analysis to identify the risk factors for development of post-operative GI complications. Potential risk factors considered in the logistic model were age, sex, angina, ejection fraction, peripheral vascular disease, renal dysfunction, redo operations, previous GI complications, priority of surgery and the use of CPB. RESULTS: A total of 1210 cases were performed on CPB, compared to 1117 off-pump. The incidence of GI complications was 1.2% (n = 14) in the on-pump group and 1.6% (n = 18) in the off-pump group (P = 0.347). The incidence of in-hospital mortality, in the patients who had a GI complication, was 28.6% (n = 4) and 22.2% (n = 4), respectively (P = 0.681). The results of the logistic regression analysis showed that renal dysfunction, advancing age and previous history of GI surgery are significant risk factors for GI complications after coronary bypass surgery whether CPB is used or not. CONCLUSIONS: Our study suggests that off-pump and on-pump techniques are similar in the rates of GI complications. We suggest that a properly designed randomized control trial is needed to verify our findings.

Neurological outcomes in coronary surgery: independent effect of avoiding cardiopulmonary bypass.

BACKGROUND: Recent studies examining neuroprotective effects of off-pump coronary artery bypass grafting (CABG) have shown inconsistent results. We examined our database to quantify the independent effects of avoidance of cardiopulmonary bypass (CPB) and aortic manipulation on neurologic outcomes after CABG. METHODS: A total of 2,327 consecutive cases undergoing isolated CABG between April 1997 and May 2001 were identified at our two institutions. Patients were divided into three groups: on CPB, off-pump with aortic manipulation, and off-pump without aortic manipulation. To control for the confounding effects of other risk factors, we performed a multivariate logistic regression analysis. Potential covariates considered in the logistic model included age, sex, redo operations, diabetes, chronic obstructive pulmonary disease, neurologic disease, peripheral vascular disease, ejection fraction, and priority of operation. RESULTS: A total of 1,210 cases were performed on CPB, compared with 520 off-pump with aortic manipulation, and 597 off-pump without aortic manipulation. The incidence of focal neurologic deficit was 1.6% (n = 19) in the on-pump group, 0.4% (n = 2) in the off-pump with aortic manipulation group, and 0.5% (n = 3) for the off-pump without aortic manipulation group (p for trend = 0.027). The results of the multivariate logistic regression analysis demonstrated that use of CPB was a risk factor for focal neurologic deficit, with an odds ratio of 3.82 (95% confidence interval, 1.41 to 10.34; p = 0.005). Aortic manipulation did not significantly influence neurologic outcome in off-pump patients. CONCLUSIONS: Off-pump operation, with or without aortic manipulation, reduces adverse neurologic outcomes compared with on-pump procedures.