On-pump Bypass Research Articles

The effects of on-pump and off-pump coronary artery bypass grafting on intraoperative graft flow in arterial and venous conduits defined by a flow/pressure ratio

Despite profound differences in the neurohumoral milieu in patients undergoing on-pump and off-pump coronary artery bypass grafting, it is uncertain how this affects graft blood flow. We prospectively recorded intraoperative transit-time flow measurements (MediStim BF 2004; MediStim AS, Oslo, Norway) in all internal thoracic artery, radial artery, and long saphenous vein conduits in patients undergoing off-pump and on-pump bypass grafting by a single surgeon. We calculated a flow/pressure ratio as a ratio of mean graft flow to mean arterial pressure for all the conduits just before chest closure. Transit-time flow measurements were recorded in 266 grafts (203 off-pump; 63 on-pump) in 100 patients (80 off-pump; 20 on-pump). Overall, mean graft flow (milliliters per minute) was higher for all grafts in the on-pump group despite a significantly lower mean arterial pressure compared with the off-pump group (P < .05). Consequently the flow/pressure ratio was greater for all grafts in the on-pump group (internal thoracic artery 0.55 vs 0.35, radial artery 0.61 vs 0.36, long saphenous vein 0.77 vs 0.55). Overall mean graft flow was significantly greater in the long saphenous vein than in the internal thoracic artery (P < .001) and radial artery (P = .001), but there was no significant difference in mean graft flow in internal thoracic artery or radial artery grafts within each group. In comparison with the off-pump group, the overall mean graft flow and flow/pressure ratio were significantly higher and mean arterial pressure significantly lower for all grafts in the on-pump group. These findings are probably a result of vasodilatation resulting from cardiopulmonary bypass and reactive hyperemia resulting from a period of ischemia. There was no difference in the mean graft flow and flow/pressure ratio of arterial grafts, which were significantly less than for long saphenous vein grafts. In patients with unstable angina and/or hemodynamic instability, in whom rapid and maximum restoration of myocardial perfusion is a priority, potentially lower graft flow in arterial grafts and off-pump surgery should be considered.

Cardiac Troponin I Concentrations during On-Pump Coronary Artery Surgery

Perioperative myocardial infarction remains a frequent complication after coronary artery bypass grafting, and is associated with a poor prognosis. This retrospective study compared cardiac troponin I concentrations after on-pump bypass grafting in 2 groups of patients: 100 operated on using a single-clamp technique to perform anastomoses, and 80 operated on using a double-clamp technique. Postoperative cardiac troponin I levels were not significantly different between groups. It was concluded that the double-clamp technique did not reduce the incidence of myocardial infarction after elective on-pump coronary artery bypass grafting, and use of a single clamp is safe with no adverse effect on postoperative outcome.

Combined Coronary Artery Re-Operation and Pulmonary Resection for Hemoptysis

We present a 59-year-old woman who underwent combined pulmonary resection for bronchiectasis with massive, recurrent hemoptysis and redo coronary artery bypass. She had previously been hospitalized four times for massive hemoptysis. She had also undergone coronary artery bypass and had symptomatic severe graft disease. We performed simultaneous right middle lobectomy and redo triple bypass. At surgery, lobectomy was performed before heparinization, then redo bypass was performed using on-pump cardiopulmonary bypass. The postoperative course was uneventful.

Coronary artery bypass grafting with or without cardiopulmonary bypass in patients with preoperative non–dialysis dependent renal insufficiency: A randomized study

Preoperative renal insufficiency is a predictor of acute renal failure in patients undergoing coronary artery revascularization with cardiopulmonary bypass. Off-pump coronary artery bypass grafting has been shown to be less deleterious than on-pump bypass in patients with normal renal function, but the effect of this technique in patients with non-dialysis dependent renal insufficiency in a randomized study is unknown. From August 2004 through October 2005, 116 consecutive patients with preoperative non-dialysis-dependent renal insufficiency (glomerular filtration rate measured using the Modification of Diet in Renal Disease equation [MDRD GFR] < or = 60 mL x min(-1) x 1.73 m(-2)) undergoing primary coronary artery bypass grafting were randomized to on-pump (n = 60) and off-pump (n = 56) groups. MDRD GFR and serum creatinine levels were measured preoperatively and postoperatively at days 1 and 5. The changes in renal function and clinical outcomes were compared between the two groups. Preoperative characteristics were comparable between the two groups. The repeated-measures analysis of variance was performed on the data that showed worsening of renal function in the on-pump group compared with the off-pump group (serum creatinine, P < .000; glomerular filtration rate, P < .000). Further analysis of subgroups of patients with diabetes alone, hypertension alone, and combined hypertension and diabetes also showed significant deterioration renal function in the on-pump group compared with the off-pump group. In covariate analysis, diabetes has emerged as a significant covariate by serum creatinine criteria while compromised left ventricular function has emerged as a significant covariate by glomerular filtration rate criteria. These analyses showed that the use of cardiopulmonary bypass is significantly associated with adverse renal outcome (P < .000). Three patents required hemodialysis in the on-pump group and none in the off-pump group. The mean number of grafts per patient was 3.85 +/- 0.86 and 3.11 +/- 0.89 in the on-pump and off-pump groups, respectively (P < .001), but the indices of completeness of revascularization, 1.00 +/- 0.08 for off-pump coronary bypass and 1.01 +/- 0.08 for on-pump coronary bypass, were similar (P = .60). This study suggests that on-pump as compared with off-pump coronary artery bypass grafting is more deleterious to renal function in diabetic patients with non-dialysis dependent renal insufficiency. MDRD GFR is a more sensitive investigation than serum creatinine levels to assess renal insufficiency in patients undergoing coronary bypass.

Coronary by-pass for bad ventricle; adoption of "hybrid-pump" bypass

BackgroundThe outcomes of on-pump and hybrid-pump bypass surgery in patients with depressed left ventricular function (EF<30%) were analyzed.Methods109 patients with preoperative left ventricular ejection fraction of <30% and bypassable circumflex coronary disease were randomized in a double blind fashion to undergo hybrid-pump (combination of off-pump and on-pump) procedure (54 patients), or on-pump coronary bypass (55 patients). In patients who underwent hybrid-pump procedure only circumflex system was bypassed on-pump to shorten CPB and myocardial ischemic time. Pre- peri and postoperative variables were analyzedResultsMean LVEF 24.4 ± 4.8%. The patients in hybrid-pump group received less graft than others, but difference was not significant. Duration of the surgery was not different statistically between hybrid-pump and on-pump groups. A longer intraoperative duration of ischemia and extra corporeal circulation was found in on-pump group. Significant improvement in the postoperative course such as shorter mechanical ventilation, less catecholamines and IABP usage, less ICU and hospital stay, less stroke, less need for hemodyalisis and most importantly less hospital mortality was observed in hybrid-pump group.ConclusionShortening the CPB and myocardial ischemic time and avoiding related problems, adoption of hybrid-pump strategy, in patients with severely impaired LVEF and bypassable circumflex coronary disease results in better outcome than conventional on-pump bypass.

Neurocognitive Outcomes in Off-Pump Versus On-Pump Bypass Surgery: A Randomized Controlled Trial

Cognitive difficulties have been reported after coronary artery bypass graft surgery using cardiopulmonary bypass. However, the cognitive benefit of off-pump surgery remains unclear. Consecutively listed candidates for elective bypass were randomly assigned to either off-pump or on-pump techniques (n = 107). A battery of 11 standardized neuropsychological tests was administered before surgery, and again at 2 and 6 months after surgery. The two groups were compared using a range of statistical procedures, including growth modeling. There were no significant differences in cognitive test scores between the off-pump and on-pump groups using t tests at any of the time points. There were no differences between off-pump and on-pump groups in the incidence of cognitive deficits at 2 months or 6 months, with the exception that fewer off-pump patients showed impairment on one test of verbal fluency at 6 months. When the pattern of cognitive change over time between the two groups was compared using sophisticated modeling techniques, the two groups were again comparable, except for results on the test of verbal fluency, in which the off-pump group showed more rapid postsurgical cognitive gains than the on-pump group. The off-pump group appears to be generally comparable to the on-pump group in terms of short-term and long-term postsurgical neurocognitive outcomes.

Activation of the coagulation system during coronary artery bypass grafting: Comparison between on-pump and off-pump techniques

The activation of the coagulation and fibrinolytic systems and platelet function in patients undergoing coronary artery bypass surgery on-pump or off-pump techniques was compared. Thirty-two patients were randomly assigned to on-pump or off-pump coronary artery bypass grafting. Heparin was given at the same dose. Activation of the coagulation and fibrinolytic systems was evaluated by measurement of several markers. Platelet function was evaluated by in vitro bleeding time test. Blood samples were collected at 7 different times, up to postoperative day 6. Overall tissue factor production was similar in the two groups. Thrombin formation was more elevated in the on-pump group (P < .001), particularly during the operation; prothrombin fragment 1.2 discharge values were higher than the preoperative ones (P = .002). Levels of tissue-plasminogen activator showed no difference between the groups (P = .1). D-dimers release was higher in the on-pump group (P = .0002). In vitro bleeding time was longer in the on-pump group (P < .0001), particularly in the first 24 hours; it was not prolonged in the off-pump group. In both groups, regardless of aspirin treatment, discharge in vitro bleeding times were lower than the preoperative ones (P < .01). Although the extrinsic coagulation pathway is similarly activated, thrombin formation is more pronounced in patients having on-pump bypass grafting. Patients subjected to off-pump bypass grafting have normally functioning platelets and a weak activation of the fibrinolytic system. At discharge, both groups have preserved platelet function and increased thrombin formation. Further studies with angiographic evaluation are needed to establish a correlation between coagulation parameters, platelet function, and graft patency.

Clinical outcomes of nonelective coronary revascularization with and without cardiopulmonary bypass

Patients who undergo emergent coronary artery bypass grafting pose a greater challenge in terms of intraoperative and postoperative mortality and morbidity compared to elective coronary artery bypass. Coronary artery bypass without cardiopulmonary bypass (off-pump coronary artery bypass) might benefit these high-risk patients by eliminating the cardiopulmonary bypass and therefore decreasing the systemic inflammatory response associated with it. The aim of this study was to compare the early clinical outcome after nonelective off-pump coronary artery bypass with a matched set of patients undergoing coronary artery bypass with cardiopulmonary bypass (on pump). Between January 2000 and October 2003, 2273 patients underwent nonelective (urgent or emergent) off-pump coronary artery bypass and were compared with a contemporaneous control group of 3487 patients undergoing on-pump coronary artery bypass. Logistic regression analysis was used to compare operative mortality, postoperative stroke, length of stay, postoperative placement of intra-aortic balloon pump, postoperative renal failure, and hemorrhage-related re-exploration between the groups, controlling for preoperative risk factors. The patients undergoing off-pump coronary artery bypass were matched to patients undergoing on-pump bypass by propensity scores. Patients undergoing off-pump coronary artery bypass had comparable operative mortality (odds ratio, 0.8; 95% confidence interval, 0.57-1.15; P = .24) and stroke rate (odds ratio, 0.6; 95% confidence interval, 0.33-1.08; P = .09) with the patients undergoing on-pump coronary artery bypass after controlling for preoperative risk factors through matching. Off-pump coronary artery bypass was associated with an abbreviated length of stay (odds ratio, 0.5; 95% confidence interval, 0.47-0.64; P < .01), lower rate of postoperative renal failure (odds ratio, 0.5; 95% confidence interval, 0.37-0.72; P < .01), intra-aortic balloon pump placement (odds ratio, 0.5; 95% confidence interval, 0.3-0.71; P < .01), and hemorrhage-related re-exploration rate (odds ratio, 0.70; 95% confidence interval, 0.5-1.0; P = .5) compared with on-pump coronary artery bypass after matching by propensity scores. Nonelective coronary revascularization without cardiopulmonary bypass is associated with comparable operative mortality and stroke and abbreviated length of stay. Off-pump coronary artery bypass might also decrease the need for intra-aortic balloon pump placement and lower the rate of postoperative renal failure and hemorrhage-related re-exploration compared with that of conventional on-pump coronary artery bypass in this subset of patients.

Aborted Off-Pump Coronary Artery Bypass Patients Have Much Worse Outcomes Than On-Pump or Successful Off-Pump Patients

Off-pump coronary artery bypass graft (CABG) surgery is purported to reduce perioperative mortality and morbidity compared with on-pump coronary bypass graft surgery. However, the outcomes of patients for whom an off-pump strategy must be changed to an on-pump procedure during surgery have not been extensively studied. The Merged Cardiac Registry (Health Data Research, Inc) contains 70 514 isolated CABG performed from January 1998 to March 2004 in 40 facilities. Among them, 62 634 patients begun and completed on-pump bypass (CPB); 7880 patients begun off-pump, of which 7424 (94.2%) completed off-pump coronary artery bypass (OPCAB), whereas 456 (5.8%) were converted to on-pump (CONVERT). CONVERT patients were more severely ill. The observed mortality of CONVERT, CPB, and OPCAB was 9.9%, 3.0%, and 1.6%, respectively, and the observed-to-predicted ratio was 2.77, 1.20, and 0.74, respectively. CONVERT also had more morbidity than either OPCAB or CPB. Finally, a risk model was created to identify patients who might be at risk for conversion from off-pump to on-pump CABG. Patients who are intended for an off-pump strategy and then require conversion to on-pump have significantly higher operative mortality and morbidity than either completed OPCAB or CPB patients. In addition, the operative mortality and morbidity are far in excess of that predicted preoperatively. Based on these results, strong consideration should be given for a planned strategy of CPB for those patients with preoperative hemodynamic instability requiring a salvage CABG operation, left ventricular hypertrophy, or previous CABG.

Markers for Perioperative Myocardial Ischemia: What Both Interventional Cardiologists and Cardiac Surgeons Need to Know

All novel markers of myocardial ischemia (ischemia-modified albumin, choline, unbound free fatty acids) lack cardiac specificity. Therefore, for the specific detection of myocardial ischemia selective blood sampling from an inserted coronary sinus catheter is needed, which limits the applicability of these markers in most clinical routine settings. In addition, the superiority of these novel markers over the calculation of myocardial lactate production, the current criterion standard for the laboratory diagnosis of myocardial ischemia, has not been demonstrated so far, and even comparative data is frequently lacking. Further the superiority of these new candidate markers over lactate determination for the diagnosis of myocardial ischemia in peripherally drawn blood samples has not been demonstrated either, and these novel parameters appear not to be a breakthrough for laboratory diagnosis of myocardial ischemia during or after percutaneous coronary interventions or coronary artery bypass grafting. The determination of cardiac troponin I or troponin T is the current criterion standard for the laboratory diagnosis of myocardial damage due to their higher sensitivities and specificities compared to creatine kinase isoenzyme MB. According to current knowledge, troponin increases in peripherally drawn blood samples must be regarded as an indicator of myocardial necrosis which, however, may be limited, only detectable by troponin and may be missed by creatine kinase isoenzyme MB determination. After on-pump coronary artery bypass grafting the generally applied troponin discriminator limits are not valid as there is limited, inevitable cardiac tissue damage occurring during the surgical procedure. Therefore, troponins are significantly increased after reperfusion of the arrested heart over values seen before bypass and also in patients without complications. Perioperative myocardial infarctions can be reliably identified by their characteristic troponin time courses, and both peak concentrations and time of peak values are diagnostic criteria. Troponin release is lower in off-pump compared to on-pump bypass surgery. Despite the controversy over the significance of troponin elevations after clinically uncomplicated and successful procedures, it is tempting to postulate that less myocardial damage as detected by troponin release is beneficial for the patient. After elective percutaneous coronary interventions, only troponin increases >8-fold the upper reference limit were associated with increased mortality in long-term follow-up.

Aortic Dissection With Potential Origin From a Mechanical Bypass Anastomosis

Ascending aortic dissection is a known complication of cardiac surgery. Off-pump coronary artery bypass surgery seems to be associated with a higher risk for this event as compared with on-pump bypass surgery. This increased risk may result from aortic side-clamping under pulsatile flow as opposed to continuous flow in conventional bypass surgery. Mechanical devices allowing performance of proximal bypass anastomoses without aortic side-clamping are supposed to reduce the risk for aortic dissection. We report a case in which ascending aortic dissection occurred 8 days after off-pump bypass surgery, most likely arising from a mechanically performed proximal bypass anastomosis.

Do Coronary Bypass Graft Flows Differ Between On-Pump and Off-Pump Operations?

The aim of this study is to compare hemodynamic factors in coronary bypass grafts on-pump and off-pump. Two propensity score-matched groups of 89 patients each including 408 dual beam Doppler flow measurements were compared. The study included only patent and single terminolateral bypass grafts. Flow was 64.9 +/- 37.3 mL/min in the on-pump group versus 58.6 +/- 35.0 mL/min in the off-pump group (p = 0.063); velocity was 23.8 +/- 10.5 versus 20.5 +/- 10.4 cm/s (p = 0.004); resistance measured as mm Hg/(mL/min(-1)) was 1.50 +/- 1.09 versus 1.76 +/- 1.14 (p = 0.020); pulsatility index was 1.98 +/- 1.52 versus 2.44 +/- 1.62 (p = 0.004). The hematocrit was 23.5 +/- 3.8% in the on-pump and 32.9 +/- 4.1% in the off-pump groups (p < 0 0.001). Multivariate analysis showed that hematocrit was the most significant factor influencing flow (p < 0.001) and velocity (p < 0.001), along with resistance (p = 0.004) and pulsatility index (p < 0.001). In a subset of 50 hemodynamic measurements made on left internal thoracic arteries implanted onto left anterior descending arteries and matched for hematocrit, there were no differences between on-pump and off-pump groups regarding flow, velocity, resistance, or pulsatility index. Off-pump compared with on-pump bypass surgery is associated with lower velocity and higher resistance in the grafts, mainly caused by changes in hematocrit and viscosity related to hemodilution.

Cost-effectiveness of on-pump and off-pump bypass surgery

We read with great interest the comprehensive review by Murphy et al. 1 This review of the published literature critically examines the potential benefits of off-pump coronary artery bypass surgery (OPCAB) compared with conventional coronary artery bypass grafting (CABG). A number of important endpoints were examined, …

Novadaq SPY: Intraoperative Quality Assessment in Off-Pump Coronary Artery Bypass Grafting

Off-pump coronary artery bypass grafting may decrease operative morbidity when compared to on-pump bypass grafting; however, it is technically demanding and thus quality control is essential. This study assesses the clinical feasibility of a new, indocyanine green (ICG)-based imaging system (SPY; Novadaq Technologies; Toronto, ON, Canada) to monitor the quality of anastomoses and grafts in off-pump revascularization. Thirty-eight consecutive patients undergoing nonemergent coronary artery bypass grafting without the use of extracorporeal circulation at two Swiss cardiac surgery clinics were included. On completion of bypass grafts, the quality of the grafts was assessed using the ICG-based imaging system. The imaging device comprises an 806-nm laser light source that is used to cause ICG to fluoresce and a near infrared-sensitive charged couple device videocamera that is used to capture the fluorescence images. ICG was administered through the central venous line, and images were acquired during the first pass of the ICG through the field of view. Graft flow (qualitative) and the quality of the grafts and anastomoses were assessed intraoperatively. Between March 2002 and September 2002, a total of 38 patients (26 men and 12 women; mean +/- SD age, 64.6 +/- 10.5 years; body mass index, 27.1 +/- 2.9) underwent surgery and imaging at two institutions. One hundred seven of 124 grafts (45 arteries and 62 veins) were analyzed. Seventeen grafts could not be assessed due to difficulties in positioning. The imaging system was easy to handle, and no adverse reactions to ICG were observed. Four of the 107 grafts imaged required revision (three anastomotic constrictions and one graft dissection). Each imaging sequence required approximately 1.25 to 2.5 mg of ICG. The images were equivalent to angiography without the need for radiographs and catheter insertion. In addition, the course of coronaries that would otherwise be difficult to locate in obese patients could be detected using the imaging system. Biochemical and ECG data demonstrated an absence of intraoperative or postoperative myocardial damage, and no liver enzyme elevation or renal dysfunction. This study supports the clinical utility of a ICG-based imaging system for the assessment of the quality of bypass grafts, which appears to be safe and simple to use.

Cost considerations in selecting coronary artery revascularization therapy in the elderly.

This article presents some of the cost factors involved in selecting coronary artery revascularization therapy in an elderly patient. With the percentage of gross national product allocated to healthcare continuing to rise in the US, resource allocation has become an issue. Percutaneous coronary intervention continues to be a viable option for many patients, with lower initial costs. However, long-term angina-free results often require further interventions or eventual surgery. Once coronary artery revascularization therapy is selected, it is worthwhile to evaluate the cost considerations inherent to various techniques. Off-pump coronary artery bypass graft surgery has seen a resurgence, with improved technology and lower hospital costs than on-pump bypass surgery. Numerous factors contributing to cost in coronary surgery have been studied and several are documented here, including the potential benefits of early extubation and the use of standardized optimal care pathways. A wide range of hospital-level cost variation has been noted, and standardization issues remain. With the advent of advanced computer-assisted robotic techniques, a push toward totally endoscopic bypass surgery has begun, with the eventual hope of reducing hospital stays to a minimum while maximizing outcomes, thus reducing intensive care unit and stepdown care times, which contribute a great deal toward overall cost. At the present time, these techniques add a significant premium to hospital charges, outweighing any potential length-of-stay benefits from a cost standpoint. As our elderly population continues to grow, use of healthcare resource dollars will continue to be heavily scrutinized. Although the clinical outcome remains the ultimate benchmark, cost containment and optimization of resources will take on a larger role in the future.

Invited commentary

Surgical revascularization for ischemic cardiomyopathy remains a controversial topic. Patient selection clearly is a major issue. In fact the STICH Trial funded by the NHLBI has been developed to give us better information on this topic. Dr Al-Ruzzeh and colleagues started with the hypothesis that off-pump revascularization was clearly superior to on-pump revascularization in patients with ischemic cardiomyopathy. The univariate analysis demonstrated that the off-pump group actually did better. More thorough statistical analysis demonstrated that in fact, the presence of cardiopulmonary by-pass was not a significant factor. The major finding that the author’s noted was preoperative VT or VF was in fact a harbinger of a poor outcome. The author’s are to be congratulated for their thorough statistical analysis in this difficult group of patients. The other question is why such a high mortality in the on-pump group? This mortality is 14%, which is certainly higher than most reported series. Our most recent publication in this group of patients has an operative mortality for less than 4% in patients undergoing on-pump bypass for ischemic cardiomyopathy [1Cope JT, Kaza AK, et al. A cost comparison of heart transplantation versus alternative operations for cardiomyopathy. Ann Thorac Surg 2001;72:1298–305Google Scholar]. The question therefore is why did this group do so poorly? Since VT/VF was a marker for poor outcome one would wonder if the mortality didn’t relate to arrhythmia deaths. In fact the majority of both the on-pump and off-pump group’s deaths were due to heart failure. Myocardial infarction also did not seem to be prevalent in either group of patients, suggesting against acute graft closure. I believe the answer is clear based on the author’s own data. Only approximately 50% in both on-pump and off-pump group of patients had angina preoperatively. Viability studies were not done by these authors in the belief that this was not necessary and could potentially exclude some patients who would benefit from having bypass surgery. I believe this is a serious error. The fact of the matter is that there was very significant mortality rate in both groups of patients and the majority of the deaths relate to heart failure. This seems to speak against patients getting much improvement in ejection fraction. This also suggests some of these patients did not have viable myocardium that could have been predicted by preoperative viability studies. We and others have suggested that ischemic cardiomyopathy can be treated with coronary revascularization if two conditions are met. There must be some viable myocardium that will be revascularized, and there should be good targets for the revascularization. We believe the absence of either of these conditions will markedly increase the mortality and have demonstrated this previously [2Langenburg SE, Buchanan SA, Sabik JF III. Predicting survival after coronary revascularization for ischemic cardiomyopathy. Ann Thorac Surg 1995;60:1193–7Google Scholar]. These authors have touched on this in that preoperative VT/VF may predict less viable myocardium. It is probably important to return to the issue of on-pump versus off-pump for this group of patients. What do we know about off-pump revascularization? Puskas and colleagues demonstrated in an excellent randomized study that off-pump surgery provided complete revascularization, was safe, with a patency equivalent to on-pump surgery. He was able to demonstrate no survival advantage in stable patients undergoing coronary bypass. He was able to demonstrate reduced blood utilization in off-pump surgery [3Hart JC, Puskas JD, et al. Off-pump coronary revascularization: current state of the art. Sem Thorac Cardiovasc Surg 2002;14:70–81Google Scholar]. It would be exciting if off pump surgery provided a survival advantage in patients undergoing coronary bypass for ischemic cardiomyopathy. Unfortunately, the present does not demonstrate that. It will take a well-designed randomized study to prove that off-pump by-pass is superior to on-pump in patients with limited ventricular reserve.

P3364 Cardiac outcome and cost-effectiveness one year after on-pump and off-pump bypass surgery

P3364 Cardiac outcome and cost-effectiveness one year after on-pump and off-pump bypass surgery

Does off-pump coronary surgery reduce morbidity and mortality?

Objective: To compare hospital outcomes of on-pump and off-pump coronary artery bypass surgery. Methods: From 1997 to 2000, primary coronary artery bypass grafting was performed in 481 patients off pump and in 3231 patients on pump. Hospital outcomes were compared between propensity-matched pairs of 406 on-pump and 406 off-pump patients. The 2 groups were similar in age (P =.9), left ventricular function (P =.7), extent of coronary artery disease (P =.5), carotid artery disease (P =.4), and chronic obstructive pulmonary disease (P =.5). However, off-pump patients had more previous strokes (P =.05) and peripheral vascular disease (P =.02); on-pump patients had a higher preoperative New York Heart Association class (P =.01). Results: In the matched pairs the mean number of bypass grafts was 2.8 ± 1.0 in off-pump patients and 3.5 ± 1.1 in on-pump patients (P <.001). Fewer grafts were performed to the circumflex (P <.001) and right coronary (P =.006) artery systems in the off-pump patients. Postoperative mortality, stroke, myocardial infarction, and reoperation for bleeding were similar in the 2 groups. There was more encephalopathy (P =.02), sternal wound infection (P =.04), red blood cell use (P =.002), and renal failure requiring dialysis (P =.03) in the on-pump patients. Conclusions: Both off- and on-pump procedures produced excellent early clinical results with low mortality. An advantage of an off-pump operation was less postoperative morbidity; however, less complete revascularization introduced uncertainty about late results. A disadvantage of on-pump bypass was higher morbidity that seemed attributable to cardiopulmonary bypass.J Thorac Cardiovasc Surg 2002;124:698-707

Off-pump coronary surgery: Effect on early mortality and stroke

Background: Avoiding cardiopulmonary bypass in coronary artery bypass grafting is thought to reduce early mortality and morbidity. Methods: We used our prospective database to compare all patients having off-pump coronary surgery (n = 389) with those having on-pump coronary surgery (n = 2412) between March 15, 1995, and November 1, 2000. Patients were grouped by age (years) in decades (>90, 80-89, 70-79, 60-69, <60 years). The Northern New England risk model was applied. Thirty-two independent variables were entered into a stepwise logistic regression analysis with the end points being surgical mortality and postoperative stroke. Results: Patients undergoing off-pump operations were older (70.9 ± 12 vs 68.1 ± 11 years; P <.001), and their Northern New England predicted risk was higher (11.9% ± 13% vs 9.2% ± 10%; P <.001). However, patients having on-pump bypass had significantly more bypass grafts constructed (3.3 ± 0.8 vs 1.9 ± 0.8; P <.001) and triple-vessel coronary artery disease (58% vs 28%; P <.001). There were no significant differences in postoperative mortality, stroke rate, complications, and length of stay between the groups. Logistic regression analysis did not show that cardiopulmonary bypass was a risk factor for either surgical mortality (odds ratio, 1.08; P =.83) or stroke (odds ratio, 1.59; P =.27). Conclusion: Off-pump coronary bypass did not reduce early mortality and morbidity. Early and late results should be compared in a prospective randomized study.J Thorac Cardiovasc Surg 2002;124:313-20

Neurocognitive dysfunction after coronary artery bypass surgery: A systematic review

Objective: Substantial, albeit scattered, evidence suggests that coronary artery bypass grafting may impair cognitive function. As methods and definitions differ greatly across studies, the reported incidence of cognitive decline after coronary bypass surgery varies widely as well. The aim of the present study was to systematically review those studies on cognitive decline that are relatively comparable and meet with certain quality criteria. Methods: Four electronic databases and the references of several abstract books and earlier reviews were used to identify relevant literature. Stringent criteria, based in part on the 1994 consensus meeting on assessment of neurobehavioral outcomes after cardiac surgery, were used to assess the studies that were found. In total, 256 different titles were found, of which 23 met with the formulated selection criteria. Results: Twelve cohort studies and eleven intervention studies were evaluated. A pooled analysis of six highly comparable studies yielded a proportion of 22.5% (95% confidence interval, 18.7%-26.4%) of patients with a cognitive deficit (a decrease of at least 1 standard deviation in at least two of nine or ten tests) 2 months after the operation. Conclusions: Neurocognitive dysfunction is a frequently occurring complication of coronary artery bypass grafting. The etiologic contribution of cardiopulmonary bypass to this complication will remain unclear until a randomized trial that directly compares off-pump and on-pump bypass surgery is carried out. (J Thorac Cardiovasc Surg 2000;120:632-9)