Off-pump coronary revascularization: current state of the art

Patients presenting for surgical coronary artery bypass grafting (CABG) are older and have more comorbidity than patients in prior decades. Cardiopulmonary bypass (CPB) may add to the elevated morbidity and mortality seen in these higher-risk patients. After the re-introduction of single-vessel bypass without CPB, surgeons have developed techniques for multivessel off-pump coronary artery bypass (OPCAB) through sternotomy. Understanding the causes of the hemodynamic disturbances seen during cardiac displacement has led to surgical techniques that minimize mechanical compression and the effects of temporary regional ischemia. With careful attention to detail, OPCAB has been shown to be feasible in nearly all patients needing coronary artery bypass. The procedure has been demonstrated to be safe and effective. Early outcomes and graft patency rates appear to be at least as good as those seen with traditional CPB-supported CABG. Certain high-risk groups may be better treated with OPCAB, but further studies are necessary to elucidate which patients should be offered OPCAB and which should receive standard CABG.     

Myocardial revascularization without extracorporeal circulation

Contemporary treatment of coronary disease includes: drug treatment, percutaneous coronary angioplasty (PCI), with or without stent implantation and surgical myocardial revascularization. For more than 30 years, conventional coronary bypass (on-pump CABG), using cardiopulmonary bypass (CPB), represented the standard regarding myocardial revascularization, particularly in patients suffering from three vessel disease or left main coronary artery stenosis. Recent development of invasive cardiology and increased interest in coronary surgery on the beating heart (OPCAB), challenging traditional on-pump CABG procedure, as optimal strategy for the treatment of coronary artery disease. In order to improve clinical outcome, OPCAB seems to be a good choice in patients with co-morbidities critical for use of CPB. Results of OPCAB revascularization in general patient population are considerably different and require further evaluation. This review article shows the development of OPCAB and elaborates potential advantages and weaknesses of this method of revascularization, from both, theoretical and clinical point of view, compared to standard surgical myocardial revascularization.     

Off-pump coronary surgery: how do the anesthetic considerations differ?

In recent years, there has been much interest in performing coronary artery bypass graft (CABG) surgery without the aid of cardiopulmonary bypass (CPB). Initial efforts focused on "minimally invasive" direct coronary artery bypass, wherein the left anterior descending artery is bypassed with an in situ left internal mammary artery graft through a small left anterior thoracotomy. A more widely adopted approach however, is off-pump CABG (OPCAB), in which CABG surgery is performed on one or more vessels through the usual median sternotomy approach without the aid of CPB. This article reviews the differences in the anesthetic considerations of OPCAB compared to conventional CABG using CPB.     

Beating‐Heart Coronary Artery Bypass Grafting With Miniaturized Cardiopulmonary Bypass Results in a More Complete Revascularization When Compared to Off‐Pump Grafting

The technique of miniaturized cardiopulmonary bypass (M‐CPB) for beating‐heart coronary artery bypass grafting (CABG) is relatively new and has potential advantages when compared to conventional cardiopulmonary bypass (CPB). M‐CPB consists of less tubing length and requires less priming volume. The system is phosphorylcholine coated and results in minimal pump‐related inflammatory response and organ injury. Finally, this technique combines the advantages of the off‐pump CABG (OPCAB) with the better exposure provided by CPB to facilitate complete revascularization. The hypothesis is that CABG with M‐CPB has a better outcome in terms of complete coronary revascularization and perioperative results as that compared to off‐pump CABG (OPCAB). In a retrospective study, 302 patients underwent beating‐heart CABG, 117 (39%) of them with the use of M‐CPB and 185 (61%) with OPCAB. After propensity score matching 62 patients in both groups were demographically similar. The most important intra‐ and early‐postoperative parameters were analyzed. Endpoints were hospital mortality and complete revascularization. Hospital mortality was comparable between the groups. The revascularization was significantly more complete in M‐CPB patients than in patients in the OPCAB group. Beating‐heart CABG with M‐CPB is a safe procedure and it provides an optimal operative exposure with significantly more complete coronary revascularization when compared to OPCAB. Beating‐heart CABG with the support of a M‐CPB is the operation of choice when total coronary revascularization is needed.     

糖尿病病人行OPCAB与CCABG的早期结果对比

目的 比较糖尿病病人非体外循环和经典体外循环冠状动脉旁路移植(OPCAB和CCABG)的术后早期临床结果.方法 1999年4月至2008年1月,318例糖尿病病人行冠状动脉旁路移植术(CABG).OPCAB 210例,CCABG 108例.两组术前总体情况差异无统计学意义.OPCAB在非体外循环、心脏跳动下完成,CCABG在体外循环、心脏停跳下完成.正中开胸,胸膜外游离带蒂左乳内动脉(LIMA),与左前降支(LAD)吻合,大隐静脉(GSV)与其他靶血管吻合,吻合口超过2个采用序贯吻合.术前口服降糖药或皮下注射胰岛素将血糖控制在6 mmol/L以下,术后早期在ICU时持续泵入胰岛素,将血糖控制在6～8mmol/L.结果 两组共5例(1.57%)死亡,7例(2.20%)发生并发症.两组均达到完全再血管化,平均移植旁路血管OPCAB组(2.6±1.1)支,低于CCABG组的(3.1±1.3)支,P＜0.05.OWCAB组死亡1例(0.48%),明显低于CCABG组4例(3.70%),P＜0.05.OPCAB组发生并发症5例(2.30%),CCABG组2例(1.85%),组间差异无统计学意义,P＞0.05.结论 糖尿病者冠状动脉旁路移植手术围术期严格控制血糖至接近正常水平,住院病死率和并发症率低.OWAB术后早期病死率明显低于CCABG.     

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.     

Off-pump coronary artery bypass grafting: initial experience at one community hospital

BACKGROUND: This study reports one cardiac surgical center's experience with off-pump coronary artery bypass (OPCAB) and compares clinical risk factors and outcomes with a group of patients undergoing coronary artery bypass grafting (CABG) with cardiopulmonary bypass at the same institution. METHODS: Data on preoperative risk factors, intraoperative clinical markers, and postoperative outcomes were collected prospectively on all patients undergoing cardiac surgical procedures at our institution. From January 1, 1999, through October 7, 1999, 332 patients underwent OPCAB procedures at our institution. This group was compared with 445 consecutive patients undergoing CABG at the same institution during the period of January 1, 1998, through November 30, 1998. RESULTS: The two groups were similar with respect to preoperative clinical risk factors. Intraoperative data showed OPCAB patients tended to have fewer grafts performed and had a lower frequency of multiple grafts to obtuse marginal vessels. Outcomes showed no differences in the incidence of perioperative stroke, mediastinitis, reexploration for bleeding, pulmonary complications, new renal failure, postoperative atrial fibrillation, or transfusion of blood products. Patients in the OPCAB group had fewer perioperative myocardial infarctions and lower incidence of postoperative low cardiac output syndrome. A higher percentage of OPCAB patients had surgical lengths of stay of 5 days or less. The OPCAB group tended to have a lower in-hospital mortality rate but this difference did not reach statistical significance. CONCLUSIONS: Off-pump coronary artery bypass grafting with revascularization of all coronary artery segments is a safe and effective procedure that can be performed with equal or improved outcomes and shorter surgical lengths of stay compared with CABG with cardiopulmonary bypass.     

Off-pump coronary artery bypass grafting in Japan

The number of coronary artery bypass grafting (CABG) procedures has reached more than 20,000 per year in Japan, and the operative mortality rate has decreased to less than 1.5% including emergent surgery. The mortality and morbidity rates of CABG are still high in patients with risk factors such as cerebrovascular disease, chronic renal failure on hemodialysis, atheromatous and calcified ascending aorta, and older age when cardiopulmonary bypass is used. Minimally invasive direct coronary bypass on a beating heart through a small left lateral anterior thoracotomy, in which the left internal thoracic artery (LITA) is used to revascularize the left anterior descending artery, was introduced for high-risk patients with single-vessel disease in the mid-1990s, although is not widely performed at present. Since the late 1990s off-pump coronary artery bypass grafting (OPCAB) has been widely performed as a treatment for multivessel disease through a median sternotomy with the evolution of stabilizers and apical suction devices, refined anesthetic management, and sophisticated surgical techniques. In 2004, 60% of all CABG procedures in Japan were performed without cardiopulmonary bypass. Due to competition from percutaneous coronary intervention with drug-eluting stents and better long-term outcomes, CABG with arterial grafts alone was carried out in 52% of total cases and in 66% of OPCAB cases. OPCAB is becoming the standard CABG in Japan.     

Current status of coronary artery bypass grafting

The number of coronary artery bypass grafting (CABG) has reached more than 21,000 cases per year in Japan, and the operative mortality has decreased less than 1% including emergent operation. There are 2 trends in CABG. One is the revival and wide spread of off-pump CABG (OPCAB). The other is multiple arterial coronary revascularization. In 2004 and 2005, 60% of all CABG procedures in Japan were performed without cardiopulmonary bypass. For competition with percutaneous coronary intervention with drug eluting stents and better long-term outcomes, CABG with only arterial grafts was carried out in 52% of total cases and 66% of OPCAB cases. OPCAB with multiple arterial grafts has been becoming the standard CABG in Japan. We reviewed OPCAB and arterial CABG including new technology.     

Nonthyroidal illness syndrome in off-pump coronary artery bypass grafting

BACKGROUND: Cardiopulmonary bypass (CPB) is an established cause of nonthyroidal illness syndrome (NTIS). Off-pump coronary artery bypass (OPCAB) has been reported to be less invasive than coronary artery bypass grafting (CABG) with CPB. We prospectively evaluated thyroid metabolism in OPCAB patients. METHODS: We analyzed free thyroid hormones (FT3 and FT4), thyroid-stimulating hormone (TSH), and reverse T3 (rT3) in 20 consecutive patients undergoing CABG surgery. Nine patients underwent CABG with CPB, and 11 underwent OPCAB. Blood samples were taken on admission, on the day of surgery (7:30 AM), after sternotomy, at the end of the operation, and at 2, 6, 12, 24, 36, 48, 72, 96, 120, and 144 hours postoperatively. The concentrations of FT3, FT4, and TSH were determined on each sample. Reverse T3 concentration was measured in 10 patients up to 48 hours and at 144 hours postoperatively. RESULTS: Baseline, operative, and postoperative variables were similar in the two groups. FT3 concentration dropped significantly (p < 0.0001), reaching its lowest value 12 hours postoperatively. There were no significant differences between CPB and OPCAB patients. FT4 varied significantly in both groups (p < 0.0001), but remained in the normal range. TSH variation was not significant. rT3 concentration rose significantly (p = 0.0002) in both groups, peaking 24 hours after surgery. CONCLUSIONS. OPCAB induces a NTIS similar to that observed after CPB, probably due to the inhibition of T4 conversion to T3. This finding suggests that NTIS is a nonspecific response to stress. CPB should not be considered as the sole trigger of NTIS in cardiac surgical patients.     

70岁以上患者不停跳冠状动脉搭桥术的临床分析

目的　探讨 70岁以上患者冠状动脉外科治疗的术式选择及不停跳搭桥术的安全性。方法　选择我科 1997年 9月至 2 0 0 3年 2月完成的≥ 70岁行不停跳搭桥术治疗患者 6 3例 ,分别与同期同一年龄组行单纯常规搭桥术的 94例患者及同期 <70岁行不停跳搭桥术的 5 8例患者进行比较、分析。结果　在术后正性肌力药物的使用率 (12例、19%与 34例、36 % )、输血率 (47例、75 %与 81例、86 % )、二次开胸率 (0例、0与 4例、4 % )、辅助呼吸时间 [(8± 6 )h与 (16± 12 )h]、院内病死率 (1例、2 %与 4例、4 % )等方面 ,≥ 70岁患者的不停跳搭桥术均优于常规搭桥术 ;≥ 70岁与 <70岁患者不停跳搭桥的术后并发症发生率 (19%与 19% )及院内病死率 (1例、2 %与 1例、2 % )差异无显著意义。结论　与行常规冠状动脉搭桥术的患者相比 ,高龄患者进行不停跳搭桥术有明显的优越性。对高龄患者行不停跳搭桥术 ,安全、临床效果确切     

Clinical outcomes, angiographic patency, and resource utilization in 200 consecutive off-pump coronary bypass patients

BACKGROUND: This retrospective study compared clinical outcomes and resource utilization in patients having off-pump coronary artery bypass grafting (OPCAB) versus conventional coronary artery bypass grafting (CABG). Angiographic patency was documented in the OPCAB group. METHODS: From April 1997 through November 1999, OPCAB was performed in 200 consecutive patients, and the results were compared with those in a contemporaneous matched control group of 1,000 patients undergoing CABG. Patients were matched according to age, sex, preexisting disease (renal failure, diabetes, pulmonary disease, stroke, hypertension, peripheral vascular disease, previous myocardial infarction, and primary or redo status. Follow-up in the OPCAB patients was 93% and averaged 13.4 months. RESULTS: Hospital death (1.0%), postoperative stroke (1.5%), myocardial infarction (1.0%), and re-entry for bleeding (1.5%) occurred infrequently in the OPCAB group. There were reductions in the rates of transfusion (33.0% versus 70.0%; p < 0.001) and deep sternal wound infection (0% versus 2.2%; p = 0.067) in the OPCAB group compared with the CABG group. Angiographic assessment of 421 grafted arteries was performed in 167 OPCAB patients (83.5%) prior to hospital discharge. All but five were patent (98.8%) (93.3% FitzGibbon A, 5.5% FitzGibbon B, 1.2% FitzGibbon O). All 163 internal mammary artery grafts were patent. Off-pump coronary artery bypass grafting reduced postoperative hospital stay from 5.7 +/- 5.3 days in the CABG group to 3.9 +/- 2.6 days (p < 0.001), with a decrease in hospital cost of 15.0% (p < 0.001). CONCLUSIONS: Off-pump coronary artery bypass grafting reduces hospital cost, postoperative length of stay, and morbidity compared with CABG on cardiopulmonary bypass. Off-pump coronary bypass grafting is safe, cost effective, and associated with excellent graft patency and clinical outcomes.     

Inflammatory response after coronary revascularization: off-pump versus on-pump (heparin-coated circuits and poly2methoxyethylacrylate-coated circuits).

OBJECTIVE: Off-pump coronary artery bypass grafting (OPCAB) may reduce the inflammatory response associated with cardiopulmonary bypass (CPB) and contribute to minimizing postoperative complications. Heparin-coated circuits and poly2methoxyethylacrylate (PMEA)-coated circuits were developed to reduce such complications. We compared the postoperative inflammatory response with or without CPB. METHODS: Eighteen consecutive patients undergoing isolated coronary artery bypass grafting (CABG) were divided into three groups: OPCAB group (n=6), heparin-coated circuits group (n=6), PMEA-coated circuits group (n=6). The plasma concentrations of the following inflammatory markers were measured: cytokines [interleukin (IL-10)], polymorphonuclear elastase (PMNE), coagulofibrinolytic factor [thrombin-antithrombin III complex (TAT)], complement factor (C3a). RESULTS: At the end of CPB, IL-10 and TAT concentrations were significantly different among the three groups (OPCAB group < PMEA-coated group < heparin-coated group). The PMNE concentration was significantly lower in the OPCAB group and the heparin-coated group as compared to the PMEA-coated group both at the end of CPB and 4 hours after CPB. C3a concentration was significantly lower in the OPCAB group than in the CPB groups at the end of CPB. Clinical variables did not differ significantly among the three groups. CONCLUSION: Off-pump CABG is associated with a reduction in the inflammatory response when compared with on-pump CABG, using either PMEA-coated or heparin-coated circuits.     

Current status of coronary artery bypass grafting

The number of cases of coronary artery bypass grafting (CABG) reached more than 21 000 in Japan in 2002, and the operative mortality decreased to less than 1%, including emergency operations. The annual number of CABGs in Japan declined 17% after 2003 to 18 000 cases in 2005 owing to unrestricted percutaneous coronary intervention (PCI) with drug-eluting stents. However, CABG is the best treatment for multivessel coronary artery disease based on the comparative data of PCI versus CABG. There have been two trends in CABG during the last decade. One is the widespread use of off-pump (OP) CABG, and the other is multiple coronary artery revascularization. In 2004 and 2005, approximately 60% of all isolated CABG procedures in Japan were performed without cardiopulmonary bypass. In a study of long-term outcomes comparing PCI with drug-eluting stents versus CABG with only arterial grafts, the latter was carried out in 52% of total cases and in 66% of OPCAB cases. OPCAB with multiple arterial grafts has become the standard CABG in Japan.     

Quantification of fat mobilization in patients undergoing coronary artery revascularization using off-pump and on-pump techniques

Fat mobilization during cardiopulmonary bypass (CPB) is a recognized risk of the procedure. Intravascular mobilization of fat emboli subsequent to CPB has been implicated in some of its recognized pathophysiologies, particularly with regard to cerebral embolic injury. The aim of this study was to investigate whether fat mobilization is still a real issue in modern perfusion practice and to determine whether off pump coronary artery bypass techniques minimize this risk. Thirty patients undergoing routine elective coronary artery bypass graft (CABG) surgery were divided into two groups. Group 1 patients underwent off pump coronary artery bypass (OPCAB) procedures, and group 2 underwent CABG supported with CPB. Blood samples were taken from the CPB patients at the beginning, middle, and end of the procedure, from the suction line, from the arterial line, and from the venous line for measurement of fat emboli present. Samples were taken at corresponding time-points from the OPCAB patients for similar measurements. Fat emboli were counted manually using Oil red O staining and light microscopy. The fat emboli were sized using calibrated microspheres as a visual size contrast. No fat emboli were observed in any of the blood samples taken from the OPCAB patients. There were fat emboli present in all samples taken during CPB from all sources. The count was highest in the suction system and lowest in the venous blood and tended to increase during CPB. There was an absence of large fat emboli in the venous blood, which tends to indicate that the larger fat emboli lodge in the microvasculature. OPCAB surgery eliminates the risk of fat embolization in patients undergoing coronary revascularization. The suction system is the major source of fat emboli during CPB, and despite the multiple filtration components of the CPB system, fat emboli of various and significant sizes do reach the patient. Fat embolization remains a risk in routine elective CABG surgery. Cardiotomy suction should be eliminated where possible.     

The clinical outcome of off-pump coronary artery bypass surgery in the elderly patients

Objective: There has been a body of evidence showing that off-pump coronary artery bypass (OPCAB) may reduce morbidity and mortality in the elderly patients. We reviewed our experience, retrospectively, on elderly patients aged 75 years and older who were operated on using the OPCAB technique. We compared their outcome to a similar group of elderly patients who were operated on using conventional coronary artery bypass grafting (CABG) with cardiopulmonary bypass (CPB) during the same period of time. Methods: Registry data and patients' notes and charts were reviewed for 56 consecutive elderly OPCAB patients (age 78.5±3.5 years) and 87 consecutive CPB patients (age 77.2±2.4 years, P=0.01). Both groups had similar risk factor profiles: Parsonnet score 17.4±4.4 (OPCAB) versus 16.6±5.2 (CPB), P=0.19. We studied in detail their preoperative and postoperative data in order to compare the outcomes of both techniques. Results: The length of stay in the intensive therapy unit (ITU) was 35.4±52.9 h for OPCAB patients and 77.6±144.9 h for CPB patients (P=0.0008). No patient died within 30 days in the OPCAB group, whilst ten (11%) CPB patients (P=0.0066) died within 30 days. The incidence of serious complications (including pulmonary oedema, septicaemia, permanent stroke and renal dysfunction requiring haemofiltration or haemodialysis) was one (2%) in the OPCAB group and 11 (13%) in the CPB group (P=0.028). CPB patients required a significantly higher number ten (12%) of intra-aortic balloon pumps (IABP) inserted compared to only one patient (2%) in the OPCAB group who required IABP insertion (P=0.05). Nine (11%) CPB patients were re-operated on for bleeding compared to no OPCAB patient (0%) needing re-operation, P=0.011. Conclusions: Although the mean age of the OPCAB group was significantly higher than the CPB group, the OPCAB group showed a significant reduction in postoperative serious morbidity, ITU stay and mortality. We believe that such a conclusion may have some effect on the decision-making and cost-effectiveness when performing coronary bypass surgery on the elderly population.     

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.     

老年人非体外循环冠状动脉旁路移植术的心肌保护作用

目的比较70岁以上老年人非体外循环冠状动脉旁路移植术(OPCAB)和体外循环冠状动脉旁路移植术(CABG)围术期心肌损伤程度,探讨OPCAB的心肌保护效果。方法30例老年患者分为两组,A组15例,为CABG组,B组15例,为OPCAB组。分别于术前、术中30min、术中1h、术后6h、12h、24h、72h、120h取静脉血标本,分别测定心肌肌钙蛋白I(cTnI)水平和CKMB活性;另外记录围手术期各项临床指标。结果OPCAB组术后辅助呼吸时间较CABG组短(P<0.01),而且主动脉球囊反搏和输血例数较低(P<0.05)。CABG组与OPCAB组cTnI、CKMB的术前水平相,术后6hcTnI即有升高而后下降,术后30min至72h均较OPCAB组明显升高(P<0.05或0.01)。结论与CABG相比,OPCAB的心肌损伤较轻,心肌保护效果较好。     

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.     

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.