Leukodepletion reduces renal injury in coronary revascularization: a prospective randomized study

BACKGROUND: Cardiopulmonary bypass (CPB) is an important contributor to renal failure, which is a well-recognized complication after coronary artery bypass grafting (CABG). Leukodepletion reduces CPB-associated inflammation and resultant end-organ injuries. However, its effectiveness in renal protection has not been evaluated in a prospective randomized clinical setting. METHODS: Forty low-risk patients awaiting elective CABG with normal preoperative cardiac and renal function were prospectively randomized into those undergoing nonpulsatile CPB without (group A: n = 20) and with leukodepletion (group B: n = 20). Renal glomerular and tubular injury were assessed by urinary excretion of microalbumin and retinol binding protein (RBP) indexed to creatinine (Cr), respectively. Daily measurements were taken from admission to postoperative day 5. Fluid balance, serum creatinine, and blood urea were also monitored. RESULTS: No mortality or renal complication occurred. Both groups had similar demographic makeups, Parsonnet scores, extents of coronary revascularization and, durations of CPB and aortic cross-clamping. Daily fluid balance, serum creatinine, and blood urea remained comparable in both groups throughout the study period. From equal preoperative values, a significantly higher release of urinary RBP:Cr (7,807 +/- 2,227 vs 3,942 +/- 2,528; p < 0.001) and urinary microalbumin:Cr (59.4 +/- 38.0 vs 4.7 +/- 6.7; p < 0.0001) occurred in group A, peaking on day 1 before returning to approximate baseline levels. CONCLUSIONS: Although clinically overt renal complications were absent, sensitive indicators revealed significantly more injury to both renal tubules and glomeruli after nonpulsatile CPB without leukodepletion. These data suggest that leukocytes play an important role in post-CPB renal dysfunction, and leukodepletion may offer some renal protection in low-risk patients during CABG.     

Myocardial Revascularization of the Beating Heart in High-Risk Patients

OBJECTIVE: Myocardial revascularization without cardiopulmonary bypass (CPB) has been proposed as an alternative technique in patients at high risk for conventional coronary artery bypass grafting (CABG). The purpose of this article is to evaluate the potential benefit of such an approach. METHODS: We retrospectively evaluated the perioperative results of off-pump CABG (OPCAB) performed from January 1995 to December 1999. Patients were divided into three groups on the basis of their preoperative risk factors: age greater than 80 years, reoperative CABG, and left ventricular ejection fraction percentage (LVEF%) less than 40%. The three subgroups were compared with patients operated on-CPB (ONCAB) during the same period of time. A total of 172 octogenarians had ONCAB versus 97 OPCAB, 307 reoperations were ONCAB versus 274 OPCAB, and 514 patients with LVEF% less than 40% were operated ONCAB versus 220 OPCAB. RESULTS: Preoperative comorbidities were homogeneously distributed in the OPCAB and ONCAB groups. More extensive coronary artery disease was found in the ONCAB groups. A trend for a lower number of perioperative complications was reported in the OPCAB groups. Freedom from overall complications was significantly higher (p < 0.005) in the OPCAB group. Actual mortality rates in the OPCAB and ONCAB groups were comparable (p = NS). CONCLUSIONS: CABG can be performed safely without CPB in patients with a high preoperative risk profile. Freedom from perioperative complications is markedly higher when the OPCAB approach is utilized.     

Does off-pump coronary artery bypass (OPCAB) surgery improve the outcome in high-risk patients?: a comparative study of 1398 high-risk patients.

OBJECTIVE: Although there has been some evidence supporting the theoretical and practical advantages of off-pump coronary artery bypass (OPCAB) over the conventional coronary artery bypass grafting (CABG) with cardiopulmonary bypass (CPB), it has not yet been determined which group of patients would benefit most from it. It has been advocated recently that high-risk patients could benefit most from avoidance of CPB. The aim of this retrospective study is to assess the efficacy of the OPCAB technique in multi-vessel myocardial revascularization in a large series of high-risk patients. METHODS: The records of 1398 consecutive high-risk patients who underwent primary isolated CABG at Harefield Hospital between August 1996 and December 2001 were reviewed retrospectively. Patients were considered as high-risk and included in the study if they had a preoperative EuroSCORE of > or =5. Two hundred and eighty-six patients were operated on using the OPCAB technique while 1112 patients were operated on using the conventional CABG technique with CPB. The OPCAB patients were significantly older than the CPB patients (68.1+/-8.3 vs. 63.7+/-9.9 years, respectively, P<0.001). The OPCAB group included significantly more patients with poor left ventricular (LV) function (ejection fraction (EF) < or =30%) (P<0.001) and more patients with renal problems (P<0.001). RESULTS: There was no significant difference in the number of grafts between the groups. The CPB patients received 2.8+/-1.2 grafts per patient while OPCAB patients received 2.8+/-0.5 grafts per patient (P=1). Twenty-one (7.3%) OPCAB patients had one or more major complications, while 158 (14.2%) CPB patients (P=0.008) developed major complications. Thirty-eight (3.4%) CPB patients developed peri-operative myocardial infarction (MI) while only two (0.7%) OPCAB patients developed peri-operative MI (P=0.024). The intensive therapy unit (ITU) stay for OPCAB patients was 29.3+/-15.4 h while for CPB patients it was 63.6+/-167.1 h (P<0.001). There were ten (3.5%) deaths in the OPCAB patients compared to 78 (7%) deaths in the CPB patients (P=0.041) within 30 days postoperatively. CONCLUSIONS: This retrospective study shows that using the OPCAB technique for multi-vessel myocardial revascularization in high-risk patients significantly reduces the incidence of peri-operative MI and other major complications, ITU stay and mortality. Even though the OPCAB group included a significantly higher proportion of older patients with poor LV function (EF < or =30%) and renal problems, the beneficial effect of OPCAB was evident.     

Total arterial off-pump versus on-pump coronary revascularization: comparison of early outcome

BACKGROUND AND AIM: To assess differences in the early outcome after complete arterial myocardial revascularization with (ONCAB) or without cardiopulmonary bypass (OPCAB). METHODS: Out of 870 consecutive CABG procedures 58 OPCAB and 91 ONCAB patients receiving exclusive arterial grafts were analyzed. OPCAB patients had more single-vessel (p < 0.0001), less triple-vessel (p < 0.0001) or left main disease (p = 0.0021), higher angina class (p = 0.003), unstable angina (p < 0.0001) or previous PTCAs (p < 0.0001). RESULTS: ONCAB was associated with longer operations (182.5 +/- 38 vs. 147 +/- 56 min; p = 0.0001) and more anastomoses/patient (3.2 +/- 1 vs. 2 +/- 0.9; p < 0.0001), but incomplete revascularization was similar in both groups (11% vs. 17%; p = ns). ITA use was identical, whereas single left internal thoracic artery (LITA) use (25.9% vs.1%; p < 0.0001) and LITA jump anastomoses (10.3% vs. 7.7%; p < 0.0001) were more frequent in OPCAB. Radial artery (RA) use (89% vs. 46.6%; p < 0.0001) and RA jump anastomoses (57.1% vs. 12.1%; p < 0.0001) were more frequent in ONCAB. Mortality, arrhythmias, cerebro-vascular accidents (CVA), and renal failure were similar, but ventilatory support shorter (8.8 +/- 11.8 vs. 15.6 +/- 9.4 h; p < 0.0001) and cardiac enzyme release smaller (p < 0.0001) after OPCAB with a trend toward less myocardial infarction (1.7% vs. 7.7%; p = 0.12) and low output (1.7% vs. 8.8%; p = 0.089), and more respiratory complications (10.3% vs. 2.2%; p = 0.056). CONCLUSIONS: Arterial OPCAB patients have less extensive CAD, but more severe symptoms. Early outcome is similar concerning mortality, arrhythmias, CVA, renal failure, or ICU and hospital stay, but with shorter ventilatory support and lower cardiac enzymes with a trend toward lower myocardial infarction and low output, but higher respiratory complication rates after OPCAB.     

Postoperative hyperthermia following off-pump versus on-pump coronary artery bypass surgery

OBJECTIVE: Hyperthermia is common in the first 24 hours following coronary artery bypass graft surgery (CABG) with cardiopulmonary bypass (CPB). An inflammatory response to CPB is often implicated in the pathophysiology of this fever. Unlike CABG with CPB, the temperature pattern after off-pump CABG (OPCAB), where CPB is avoided, has not yet been described. The purpose of this study was to describe the postoperative temperature pattern following OPCAB and to compare it with that following on-pump cardiac surgery. DESIGN: Retrospective, observational study. SETTING: Tertiary care university hospital. PARTICIPANTS: Consenting patients undergoing CABG or OPCAB procedures. INTERVENTIONS: Observational. MEASUREMENTS AND MAIN RESULTS: Of the CABG patients, 89% had temperature elevations above 38 degrees C, versus 44% of the OPCAB patients (P = 0.04). Peak body temperature was higher in the on-pump patients (CABG 38.5 degrees C +/- 0.4 degrees C versus OPCAB 37.9 degrees C +/- 0.5 degrees C; P = 0.002), as was the area under the curve for temperatures greater than 38 degrees C (CABG 1.6 +/- 1.7 degrees C/hr versus OPCAB 0.4 +/- 1.2 degrees C/hr; P = 0.02). CONCLUSIONS: Off-pump CABG surgery patients experience less hyperthermia compared with on-pump CABG patients. The reasons for a lower incidence and severity of hyperthermia after OPCAB surgery are not known, but may be related to a reduced inflammatory response.     

A prospective randomized study to evaluate splanchnic hypoxia during beating-heart and conventional coronary revascularization

Objective: Cardiopulmonary bypass (CPB) is associated with gut mucosal hypoxia, which may contribute to gastrointestinal complications. We examined gastric mucosal oxygenation together with whole-body oxygen flux in low-risk patients undergoing coronary artery bypass grafting (CABG) with and without CPB. Methods: Fifty-four patients undergoing primary CABG by the same surgeon were randomized into either on-pump (ONCAB, n=27) or off-pump (OPCAB, n=27) groups. The ONCAB group underwent mild hypothermic (35°C) pulsatile CPB with arterial line filtration. Each patient underwent perioperative monitoring with continuous tonometry and cardiac output devices. Gastric intramucosal pH (pHi), gastric-arterial carbon dioxide partial pressure difference (CO₂ gap), whole-body oxygen delivery (DO₂) and consumption (VO₂) and whole-body oxygen extraction fraction were measured at sequential time-points intraoperatively and up to 6 h postoperatively. Anaesthetic management was standardized. Results: Both groups had similar demographic makeup and extent of revascularization (ONCAB 2.6±0.9 grafts versus OPCAB 2.5±0.8 grafts; P=0.55). The ONCAB group had a mean (±SD) CPB time of 62±25 min and aortic cross-clamp time of 32±11 min. In both groups there was a similar and progressive drop in pHi intraoperatively. Postoperatively, there was a gradual separation between the groups with ONCAB patients showing no further decline in pHi, while further deterioration was observed in the OPCAB group up to 6 h postoperatively. There was a significant difference between the groups over time (P=0.03). There was a corresponding progressive rise in CO₂ gap perioperatively in both groups, with ONCAB patients demonstrating superior preservation of gastric mucosal oxygenation in the early postoperative period. Global oxygen utilization measurements showed superior DO₂ and VO₂ in the OPCAB group throughout the study. Conclusions: Despite superior global oxygen flux associated with beating-heart revascularization, gastric mucosal hypoxia occurred to similar extents in both groups with worsening trends for the OPCAB patients postoperatively. The splanchnic pathophysiology during beating-heart revascularization should be further explored.     

Comparison of minimally invasive closed circuit extracorporeal circulation with conventional cardiopulmonary bypass and with off-pump technique in CABG patients: selected parameters of coagulation and inflammatory system.

OBJECTIVE: Closed circuit extracorporeal circulation (CCECC) has been developed to reduce deleterious effects of standard cardiopulmonary bypass (CPB). This study compares the effects of CCECC (CORx system), CPB, and off-pump coronary artery bypass grafting (OPCAB) on red blood cell damage, coagulation activation, fibrinolysis and cytokine expression. METHODS: Thirty patients underwent coronary artery bypass grafting (CABG). Twenty of them were randomized into two groups: CCECC (n = 10), CPB (n = 10). While not randomized, OPCAB (n = 10) served as a separate reference group. CCECC and CPB patients received cardioplegic arrest. Interleukin 6 (IL-6), free hemoglobin (fHb), von Willebrand factor activity (vWf), thrombin-antithrombin-III-complex (TATc), prothrombin fragment 1.2 (F 1+2) and plasmin-antiplasmin complex (PAPc) were assessed preoperatively, perioperatively and 24 h postoperatively. RESULTS: CCECC showed significantly lower red blood cell damage than CPB (fHb: CCECC, 7.1+/- 5.7 micromol/l; CPB, 16.8+/-11.4 micromol/l; P = 0.025; OPCAB, 3.4+/-1.1 micromol/l). Perioperatively, CCECC exhibited significantly lower activation of coagulation and fibrinolysis than CPB, but did not differ from OPCAB (vWf: CCECC, 133+/-52%; CPB, 241+/-128%; P = 0.052; OPCAB, 153+/-58%; TATc: CCECC, 4.7+/-0.9 ng/ml; CPB, 31.1+/-15.8 ng/ml; P < 0.001; OPCAB, 2.4+/-0.6 ng/ml; PAPc: CCECC, 214+/-30 ng/ml; CPB, 897+/-367 ng/ml; P < 0.001; OPCAB, 253+/-98 ng/ml). In contrast, fibrinolysis markers and IL-6 were markedly increased in CCECC postoperatively (PAPc: CCECC, 458+/-98 ng/ml; CPB, 159+/-128 ng/ml; P < 0.001; OPCAB, 262+/-174 ng/ml; IL-6: CCECC, 123.4+/-49.8 pg/dl; CPB, 18.8+/-13.1 pg/dl; P < 0.001; OPCAB, 31.6+/-26.2 pg/dl). CONCLUSIONS: CCECC for CABG is associated with a significant reduction of red blood cell damage and activation of coagulation cascades similar to OPCAB when compared with conventional CPB while a delayed fibrinolytic and inflammatory activity was observed. These findings require further investigation to verify the promising concept of CCECC.     

Multivessel off-pump coronary artery bypass surgery in the elderly.

OBJECTIVE: Coronary artery bypass grafting in the elderly patient is associated with increased perioperative morbidity and mortality. The avoidance of cardiopulmonary bypass (CPB) in this population is potentially beneficial. We examined our initial experience with off-pump multivessel coronary artery revascularization in patients aged 70 years and older. METHODS: In a consecutive series of 300 off-pump coronary artery bypass (OPCAB) operations performed by a single surgeon between 1996 and 1999, 98 patients were aged 70 years and older. These patients were compared with a consecutive cohort of 497 patients aged 70 years and older operated on with CPB in the same institution from 1995 to 1996, period where OPCAB surgery was not performed in our institution. RESULTS: Patients in the beating heart group were older (75+/-4 vs. 74+/-3 years; P=0.001). Gender distribution and other preoperative risk factors were comparable for the two groups. On average, 3.0+/-0.8 and 2.8+/-0.7 grafts per patient were completed in the OPCAB and the CPB groups, respectively (P=0.007). Perioperative mortality rates (OPCAB group, 3.1%; CPB group, 3.6%), perioperative myocardial infarction (OPCAB, 2.0%; CPB, 5.1%) and neurologic events (OPCAB, 1.0%; CPB, 3.2%) were comparable for the two groups. The incidence of postoperative atrial fibrillation was lower in the OPCAB group (42 vs. 54%; P=0.05). The need for allogenic blood transfusions was significantly less in the OPCAB group (53 vs. 82%; P=0.001). CONCLUSIONS: In patients aged 70 years and older, multivessel OPCAB surgery is associated with lower rates of postoperative atrial fibrillation and reduced transfusion requirements. Multivessel OPCAB in the elderly patient is an acceptable alternative to procedures performed with CPB.     

Off-pump versus on-pump coronary artery bypass surgery and postoperative renal dysfunction

Renal dysfunction is a serious complication after coronary bypass surgery with cardiopulmonary bypass (CABG). Because duration of cardiopulmonary bypass (CPB) is associated with renal outcome, it has been proposed that avoidance of CPB with off-pump coronary bypass (OPCAB) may reduce perioperative renal insult. We therefore tested the hypothesis that OPCAB is associated with less postoperative renal dysfunction compared with CABG surgery. With IRB approval, we gathered data for 690 primary elective coronary bypass patients (OPCAB, 55; CABG, 635). Perioperative change in creatinine clearance (DCrCl) was calculated by using preoperative (CrPre) and peak postoperative (CrPost) serum creatinine values, and the Cockroft-Gault equation (DCrCl = CrPreCl - CrPostCl). Univariate and linear multivariate tests were used in this retrospective analysis; P: < 0.05 was considered significant. Multivariate analysis did not identify OPCAB surgery as an independent predictor of DCrCl. However, previously reported associations of PreCrCl, age, and diabetes with DCrCl were confirmed. Power analysis demonstrated an 80% power to detect a 7.0 mL/min DCrCl difference between study groups. In this retrospective study, we could not confirm that OPCAB significantly reduces perioperative renal dysfunction compared with CABG surgery. Our findings suggest that reduction of renal risk alone should not be an indication for OPCAB over CABG surgery. Implications: Retrospective analysis did not identify any significant difference in perioperative change in creatinine clearance after coronary revascularization with cardiopulmonary bypass compared with off-pump coronary surgery.     

Totally arterial off-pump vs. on-pump coronary revascularization: comparison of early outcome

Our objective was to assess differences in early outcome after completely arterial myocardial revascularization with (on-pump coronary artery bypass grafting or ONCAB) or without cardiopulmonary bypass (off-pump coronary artery bypass grafting or OPCAB). Fifty-eight OPCAB and 91 ONCAB patients receiving exclusively arterial grafts were analyzed. OPCAB patients had more single-vessel (P<0.0001), less triple-vessel (P<0.0001) or left main disease (P=0.0021), higher angina class (P=0.003), more unstable angina (P<0.0001) and previous percutaneous transluminal coronary angioplasty (PTCA; P<0.0001), but similar EuroScores (P=n.s.). ONCAB was associated with longer operation time (P=0.0001) and more anastomoses/patient (P<0.0001). Internal thoracic artery (ITA) use was identical, whereas single left ITA use (P<0.0001) and left ITA jump anastomoses (P<0.0001) were more frequent in OPCAB. Radial artery (RA) use (P<0.0001) and RA jump anastomoses (P<0.0001) were more frequent in ONCAB. Complication rates were similar concerning mortality, arrhythmias, cerebro-vascular accidents (CVA), and renal failure with shorter ventilatory support (P<0.0001) and a trend towards less perioperative myocardial infarction (PMI) (P=0.12) and low output (P=0.089), and more respiratory complications (P=0.056) after OPCAB. Arterial OPCAB patients have less extensive CAD, but more severe symptoms. Early outcome is similar concerning mortality, arrhythmias, CVA, renal failure, or intensive care unit and hospital stay, but with shorter ventilatory support and a trend towards lower PMI and low output, and higher respiratory complication rates after OPCAB.     

Coronary artery bypass grafting with cardiopulmonary bypass versus off-pump cardiopulmonary bypass grafting: does eliminating the pump reduce morbidity and cost?

BACKGROUND: Cardiopulmonary bypass (CPB) may contribute to the complications and cost of coronary artery bypass grafting (CABG). Off-pump CABG (OPCAB) allows coronary revascularization without CPB. We hypothesized that OPCAB provides satisfactory graft patency while reducing complications and cost compared with CABG with CPB. METHODS: We prospectively followed 80 patients undergoing CABG: 40 patients undergoing OPCAB and 40 patients undergoing CABG with CPB. OPCAB patients underwent angiography within 48 hours of surgery to determine early graft patency. Incidence of complications, length of stay, and costs were recorded for each patient. The influence of the number of vessels bypassed was analyzed. RESULTS: OPCAB patients (n = 40) underwent grafting of 2.7 +/- 0.7 vessels per patient compared with 3.6 +/- 0.8 vessels per patient in the CABG with CPB group (n = 40) (p < 0.0001). Angiography demonstrated 105 of 108 (97%) of grafts were patent in the OPCAB group. Incidence of complications, length of stay, and costs did not differ between the OPCAB and CABG with CPB groups. Number of vessels grafted showed a positive correlation to total costs in both groups. CONCLUSIONS: While OPCAB provided satisfactory early graft patency, there was no significant difference between OPCAB and CABG with CPB with regard to cost, length of stay, or incidence of complications. In this study, eliminating CPB did not reduce morbidity or cost after CABG.     

Is cardiopulmonary bypass a reason for aspirin resistance after coronary artery bypass grafting?

OBJECTIVE: 'Off-pump' coronary artery bypass grafting (OPCAB) is an alternative to conventional coronary artery bypass grafting (CABG) using cardiopulmonary bypass (CPB). While midterm results after OPCAB have become available, systematic studies of changes in platelet function after OPCAB are still missing. Since we have previously shown that oral aspirin treatment (100mg) does not achieve sufficient platelet inhibition in the majority of patients operated on with CPB, we hypothesized that bypass surgery without CPB (off-pump coronary artery bypass, OPCAB) causes less impairment of platelet inhibition by aspirin. The aim of this study was to investigate platelet function and the antiplatelet effect of aspirin after off-pump coronary artery bypass grafting in comparison with conventional on-pump surgery. METHODS: We compared platelet function (in vitro aggregation and thromboxane formation) before and at days 1 and 5 after coronary artery bypass grafting, performed with (n=15) or without (n=14) CPB. Oral aspirin treatment (100mg/d) was started at day 1 after surgery. RESULTS: After a 5 day oral treatment with aspirin, platelet aggregation was inhibited significantly in OPCAB-patients to 55.7+/-16.3% of control before surgery (P<0.05), whereas aggregation remained unchanged after CPB (105.8+/-26.9% of control before surgery; P>0.05). Since aspirin primarily inhibits platelet thromboxane formation, thromoboxane was determined after in vitro aggregation. According to platelet aggregation, thromboxane formation was only inhibited significantly after OPCAB (29.2+/-13.0% of control before surgery, P<0.05), but not after CPB (74.5+/-21.4% of control before surgery, P>0.05). This resistance to aspirin after CPB may be caused by an increased release of new platelets which are competent to form thromboxane, since the number of platelets decreased from 237+/-11x10(3)/microl before CPB to 174+/-13x10(3)/microl at day 1 after surgery and increased significantly the following days reaching 303+/-17x10(3)/microl at day 5. Platelet counts of patients operated on without CPB showed no significant changes (236+/-16x10(3)/microl before OPCAB, 220+/-16x10(3)/microl at day 1 and 266+/-31x10(3)/microl at day 5 after surgery). CONCLUSIONS: The antiplatelet effect of aspirin is largely impaired after CPB, but not after CABG without CPB. Hence, increased platelet turnover after CPB seems to contribute to aspirin resistance, since an increased number of platelets might be competent to form thromboxane within the dosing intervals.     

Perioperative and mid-term results of coronary bypass surgery in patients undergoing chronic dialysis.

PURPOSE: The goal of this study was to evaluate perioperative and mid-term results of coronary artery bypass grafting (CABG) in patients with end-stage renal disease (ESRD). METHODS: Thirty-five consecutive dialysis patients who required CABG over a 5-year period were investigated retrospectively. RESULTS: Mean patient age was 62.5+/-11.5 years. The mean number of diseased vessels was 2.3W0.8. Off-pump CABG (OPCAB) was performed in 12 patients. The mean number of anastomoses per patient was 2.5+/-1.1. The perioperative mortality was 5.7%, and the average duration of hospitalization was 25.3+/-13.4 days. Overall 5-year survival rates were 63.7%. The cardiac-related 5-year survival rate was 89.3%, and the cardiac event-free rate was 51.7%. Multivariate analysis failed to identify any significant prognosticators for perioperative or long-term outcomes. The morbidity rate was significantly lower in patients undergoing OPCAB than in patients undergoing conventional CABG (8.3 vs. 47.8%; p=0.03). Perioperative mortality in the OPCAB group was 0%, and the average duration of hospitalization was shorter in the OPCAB group than in the conventional CABG group (19.7 days vs. 28.5 days; p=0.1). CONCLUSION: In the context of coronary artery bypass surgery, OPCAB produced better outcomes than conventional CABG procedure in patients undergoing chronic dialysis. Further-more, OPCAB procedure seems to offer a greater benefit to dialysis patients than non-dialysis patients.     

Off-pump versus on-pump reoperative CABG via a left thoracotomy for circumflex coronary artery revascularization

OBJECTIVE: Reoperative CABG via a left thoracotomy (RCLT) has become a useful approach for revascularization of the circumflex coronary territory for patients who are at high risk for conventional approach. This study compares the results of RCLT using cardiopulmonary bypass (CPB) with those of a beating heart technique (OPCAB). METHODS: Thirty-two patients who underwent RCLT over the past 10 years were included. Fourteen patients undergoing on-pump RCLT (CPB) were compared to 18 patients undergoing off-pump RCLT (OPCAB). Baseline characteristics of the study groups were similar. Follow-up was 100% complete. A single graft was performed in all patients except one who had two grafts. RESULTS: There were no deaths or perioperative myocardial infarctions in either group. The incidence of atrial fibrillation (CPB: 29% vs. OPCAB: 11%) and the percentage of patients requiring ventilator support longer than 24 hours (21% vs. 6%) was not significantly different between the groups. However, allogeneic blood product utilization (0.9 +/- 1.2 vs. 0.3 +/- 0.7 units, p = 0.04), ICU stay (65 +/- 79 vs. 28 +/- 16 hours, p = 0.04) and total hospital length of stay (8 +/- 4 vs. 5 +/- 1 days, p = 0.001) were significantly lower in the OPCAB group. Average follow-up for the entire cohort was 33 +/- 9.8 months (range 2-102 months). Three-year survival was 74 +/- 9% with 9 deaths (28%) during the follow-up, but only 3 (9%) were cardiac related. Reinterventions were indicated in 6 patients (19%) (PTCA; 5, CABG: 1). Follow-up was longer for the CPB group (51 +/- 33 vs. 19.5 +/- 14 months, p = 0.001). Three-year survival (CPB 69 +/- 13%, OPCAB: 82 +/- 12%, p = 0.47) and reintervention rates (CPB: 3 [21%], OPCAB: 3 [17%], p = 0.33) were similar between the groups. CONCLUSIONS: RCLT is an effective and safe approach for circumflex artery revascularization with excellent short- and mid-term results using either technique. The OPCAB technique is associated with reduced blood product utilization and shorter ICU and hospital length of stay and, therefore, is more cost-effective.     

Does off-pump coronary artery bypass reduce the incidence of clinically evident renal dysfunction after multivessel myocardial revascularization?

In this prospective, observational trial, we determined whether off-pump coronary artery bypass (OPCAB) was associated with less postoperative renal dysfunction (RD) compared with coronary bypass surgery with cardiopulmonary bypass (CABG). All patients undergoing primary, isolated coronary surgery at our institution in the year 2000 participated. Data collected on each patient included demographics, preoperative risk factors for RD, perioperative events, and serum creatinine concentrations from date of admission until discharge or death. The criteria for RD was both a >or=50% increase from preoperative creatinine and an absolute postoperative creatinine >or=2.0 mg/dL (177 microM). Student's t-test or the Fisher's exact test was used to compare groups. Stepwise multiple logistic regression identified determinants of RD; P < 0.05 significant. The CABG group (n = 119) differed from the OPCAB group (n = 220) with respect to age (64 +/- 13 versus 67 +/- 10 yr, P = 0.0074) and number of distal grafts (median 4 versus 3, P = 0.0003). Type of operation did not associate with the presence of postoperative RD: 18 (8.2%) of 220 OPCAB patients versus 12 (10%) of 119 CABG patients (P = 0.55). Our data suggest that choice of operative technique (OPCAB versus CABG) is not associated with reduced renal morbidity.     

Conversion in off-pump coronary artery bypass grafting: an analysis of predictors and outcomes

BACKGROUND: The incidence, predictive factors, and outcomes related to conversion from off-pump coronary artery bypass (OPCAB) to on-pump coronary artery bypass grafting (ONCAB) have not been well defined. We sought to determine the incidence of conversion, predictive factors, and any associated adverse consequences. METHODS: From January 2000 through June 2002, 1,644 patients underwent nonemergent OPCAB with 61 patients requiring conversion from OPCAB to ONCAB. These groups were retrospectively compared by univariate and multivariate regression analysis. The converted group was then computer matched 1:3, to a cohort of ONCAB patients to determine differences in outcomes. RESULTS: The overall conversion rate was 3.71%. Converted patients compared with a computer-matched ONCAB patients had a higher incidence of operative mortality (18.0% versus 2.7%, p < 0.001). Urgently converted patients had a higher incidence of postoperative cardiac arrest (25% versus 1.1%, p < 0.001), multisystem organ failure (10.7% versus 0.6%, p < 0.001), vascular complications (7.1% versus 1.1%, p = 0.03), and perioperative myocardial infarction (10.7% versus 1.1%, p = 0.02). Predictive factors for conversion were surgeon early in OPCAB experience (odds ratio [OR] 4.4), previous CABG (OR 2.8), and congestive heart failure (OR 2.0). The need for urgent-emergent conversion was highly predictive for operative mortality (OR 7.3) compared with elective conversion. CONCLUSIONS: Patients undergoing urgent-emergent but not elective conversion from OPCAB to ONCAB had a significantly higher risk of mortality and morbidity compared with patients whose procedure was initially ONCAB. Variables predictive of conversion included previous CABG, congestive heart failure, and surgeons early in OPCAB experience.     

Coronary artery bypass grafting: an off-pump versus on-pump review

There has been a proliferation in the number of coronary artery bypass grafts (CABG) being performed without the use of cardiopulmonary bypass (CPB). However, the benefits of off-pump coronary artery grafting (OPCAB) are still being determined. The aim of this retrospective review was to compare the perioperative outcomes of CPB patients with OPCAB patients and to identify the patients most likely to benefit from the off-pump procedure. We reviewed the perioperative data of all isolated CABG patients at two metropolitan hospitals for the period of August 2000 to September 2001. The two groups (OPCAB vs. CPB) were further divided into subgroups identifying patients by their predicted mortality (higher-risk and lower-risk) and the number of distal graft anastomoses received (1, 2, 3, 4, or 5). A p value less than .05 was considered significant. Out of the total of 882 patients, 46.2% were OPCAB cases. Both CPB and OPCAB groups were similar in terms of demographics and predicted risk of mortality. Intraoperatively, OPCAB patients had fewer distal graft anastomoses (2.4 +/- 1.0 vs. 3.2 +/- 1.0, p < .001). Postoperatively, patients in the OPCAB group had less chest drainage (889 +/- 588 vs. 989 +/- 662 mls, p < .001), sustained fewer strokes (0.2 vs. 1.9%, p < .05), were transfused less (15.4 vs. 32.5%, p < .001) and were discharged earlier (7.3 +/- 5.6 vs. 8.5 +/- 9.1 days, p < .05). For higher-risk patients, OPCAB was associated with fewer reoperations for bleeding (1.3 vs. 6.4%, p < .05), a lower stroke rate (0 vs. 3.2%, p < .05), and a trend toward lower mortality (7.1 vs. 15.1%, p = .08). However, lower-risk OPCAB patients' stroke incidences (0.5% OPCAB group vs. 1.4% CPB group), and mortality rates (0.5 vs. 0.5%) were similar. Comparisons by number of grafts performed revealed that only the single-grafted OPCAB patients had statistically fewer postoperative complications, reduced chest drainage, and a shorter intensive care stay. Differences between either operation groups in transfusion rates were only statistically significant for the one to three grafted patients, while postoperative stays were similar for patients having four grafts. These results suggest that OPCAB is associated with a reduction in mortality and morbidity, particularly within the higher-risk patients. However, the benefits of OPCAB diminished with an increasing number of distal anastomoses performed.     

Does Off‐Pump Revascularization Reduce Coronary Endothelial Dysfunction?

BACKGROUND: Off-pump coronary revascularization (OPCAB) has been shown to reduce markers of acute inflammation but its effect on coronary endothelial function is unknown. This experimental study sought to determine whether OPCAB reduces endothelial dysfunction, compared to standard cardiopulmonary bypass (CPB) with and without the anticomplement agent soluble complement receptor-1 (sCR(1)). METHODS: In 10 pigs, OPCAB was simulated by snaring the left anterior descending (LAD) artery for 15 minutes followed by 3 hours of reperfusion. On-pump revascularization was simulated in 20 pigs by 15 minutes of LAD occlusion on CPB with cold blood cardioplegic arrest followed by 3 hours of reperfusion. Ten of these animals received sCR(1) (10 mg/kg) prior to CPB. Inflammatory response was monitored by percent (%) lung water increase, wall motion scores (WMS) with transthoracic echocardiography where 4 = normal to -1 = dyskinesia, and endothelial function in the distal LAD with bradykinin-induced coronary artery relaxation using organ chamber methodology. RESULTS: OPCAB had no effect on lung edema (% increase = 1.7 +/- 1.4 OPCAB vs. 3.4 +/- 0.5 CPB vs. 2.3 +/- 0.9 CPB + sCR(1)) and failed to prevent wall motion changes (WMS = 2.65 +/- 0.08 OPCAB vs. 2.70 +/- 0.04 CPB vs. 3.10 +/- 0.07* CPB + sCR(1), *p < 0.01) and coronary endothelial dysfunction (% relaxation = 41 +/- 9 OPCAB vs. 40 +/- 9 CPB vs. 78 +/- 8** CPB + sCR(1), **p < 0.001), which was best preserved with sCR(1). CONCLUSIONS: This study suggests that agents which directly inhibit complement activation such as sCR(1) are more important in preventing endothelial dysfunction during coronary revascularization than merely avoiding CPB.     

Off-pump surgery decreases postoperative complications and resource utilization in the elderly.

BACKGROUND: Bypass surgery in the elderly (age >70 years) has increased mortality and morbidity, which may be a consequence of cardiopulmonary bypass. We compare the outcomes of a cohort of elderly off-pump coronary artery bypass (OPCAB) patients with elderly conventional coronary artery bypass grafting (CABG) patients. METHODS: Chart and provincial cardiac care registry data were reviewed for 30 consecutive elderly OPCAB patients (age 74.7 +/- 4.2 years) and 60 consecutive CABG patients (age 74.9 +/- 4.1 years, p = 0.82) with similar risk factor profiles: Parsonnet score 17.2 +/- 8.1 (OPCAB) versus 15.6 +/- 6.5 (CABG), p = 0.31; and Ontario provincial acuity index 4.5 +/- 1.9 (OPCAB) versus 4.3 +/- 2.0 (CABG), p = 0.65. RESULTS: Mean hospital stay was 6.3 +/- 1.8 days for OPCAB patients and 7.7 +/- 3.9 days for CABG patients (p < 0.05). Average intensive care unit stay was 24.0 +/- 10.9 h for OPCAB patients versus 36.6 +/- 33.5 h for CABG patients (p < 0.05). Atrial fibrillation occurred in 10.0% of OPCAB patients and 28.3% of CABG patients (p < 0.05). Low output syndrome was observed in 10% of OPCAB patients and 31.7% of CABG patients (p < 0.05). Cost was reduced by $1,082 (Canadian) per patient in the OPCAB group. Postoperative OPCAB graft analysis showed 100% patency. CONCLUSIONS: OPCAB is safe in the geriatric population and significantly reduces postoperative morbidity and cost.     

Cumulative sum failure analysis of a policy change from on-pump to off-pump coronary artery bypass grafting

BACKGROUND: Use of the sequential probability cumulative sum (CUSUM) technique may be more sensitive than standard statistical analyses in detecting a cluster of surgical failures. We applied CUSUM methods to evaluate the learning curve after a policy change by a single surgeon from routine on-pump (cardiopulmonary bypass [CPB]) to off-pump coronary artery bypass grafting (OPCAB). METHODS: Fifty-five consecutive first-time coronary artery bypass patients (CPB group) were compared with the next 55 patients undergoing an attempt at routine OPCAB using the same coronary stabilizer. The goal in OPCAB patients was to obtain complete revascularization, albeit with a low threshold for conversion to CPB to maximize patient safety during the learning curve. Preoperative patient risk was calculated using previously validated models of the Cardiac Care Network of Ontario. The occurrence of operative mortality and nine predefined major complications (myocardial infarction, bleeding, stroke, renal failure, balloon pump use, mediastinitis, respiratory failure, life-threatening arrhythmia, and sepsis) was compared between the CPB and OPCAB groups using Wilcoxon, Fisher exact, and two-tailed t tests, as well as CUSUM methodology. An intention to treat analysis was performed. RESULTS: The CPB and OPCAB groups had similar predicted mortality and length of stays (2.2% +/- 2.5%, 8.1 +/- 2.5 days versus 2.4% +/- 3.5%, 8.1 +/- 2.4 days, respectively). The mean number of grafts per patient was 3.1 +/- 0.7 in the CPB group versus 3.0 +/- 0.7 in the OPCAB group (p = 0.45). Two of 55 (3.6%) CPB patients died, as opposed to 1 of 55 (1.8%) OPCAB patients (p = 0.99). Eight of 55 CPB patients (14.5%) incurred major complications, as opposed to 4 of 55 (7.3%) OPCAB patients (p = 0.36). Median hospital length of stay was 6.0 days in the CPB group versus 5.0 days in the OPCAB group (p = 0.28). On CUSUM analysis, the failure curve in CPB patients approached the upper 80% alert line after eight cases, whereas the curve in OPCAB patients reached below the lower 80% (reassurance) boundary 28 cases after the policy change, indicating superior results in the OPCAB group despite the learning curve. CONCLUSIONS: A policy change from coronary artery bypass on CPB to routinely attempting OPCAB can be accomplished safely despite the learning curve. CUSUM analysis was more sensitive than standard statistical methods in detecting a cluster of surgical failures and successes.