A review of 1,582 consecutive Octopus off-pump coronary bypass patients

Cardiac Output Values and Correlation of Renal Injury with Neutrophil Gelatinase-Associated Lipocalin Levels in Off-Pump Coronary Artery Bypass Patients

Objective

To investigate the correlation between cardiac output values and renal neutrophil gelatinase-associated lipocalin (NGAL) levels as a biomarker of renal ischemia.

Methods

Forty patients, who underwent off-pump coronary artery bypass (OPCAB) surgery and in whom the positioning of the heart was fixed with simple suspension sutures without a mechanical stabilizer, were included in the study. Continuous cardiac output (CO) measurements were recorded using the arterial pressure waveform analysis method (FloTrac sensor system) in the perioperative period. CO was recorded every minute during non-anatomical cardiac positioning for left anterior descending artery (LAD), diagonal artery (D), circumflex artery (Cx), and right coronary artery (RCA) bypasses. Serum NGAL samples were analyzed in the preoperative, perioperative, and postoperative periods.

Results

The CO values measured at various non-anatomical cardiac positions during distal anastomosis for LAD, D, Cx, and RCA were significantly lower than pre- and postoperative values measured with the heart in normal anatomical position (3.45±0.78, 2.9±0.71, 3.11±0.56, 3.19±0.81, 5.03±1.4, and 4.85±0.78, respectively, P=0.008). There was no significant difference between CO values measured at various non-anatomical cardiac positions during distal anastomosis. Although there was no significant correlation between NGAL levels and age, duration of surgery, preoperative CO, D-CO, RCA-CO, and postoperative CO measurements, there was a significant correlation between NGAL levels and LAD-CO (P=0.044) and Cx-CO (P=0.018) at the postoperative 12^th hour.

Conclusion

Full revascularization may be achieved by employing the OPCAB technique while using simple suspension sutures without a mechanical stabilizer and by providing safe CO levels and low risk of renal ischemia.

Off-Pump versus Conventional Coronary Artery Bypass Grafting: A Meta-Analysis and Consensus Statement from the 2004 ISMICS Consensus Conference

Background

The purpose of this evidence-based consensus statement is to systematically review and meta-analyze the randomized and nonrandomized evidence comparing off-pump (OPCAB) to conventional coronary artery bypass (CCAB) surgery and to provide consensus on the role of OPCAB in low- and high-risk surgical patients.

Methods and Results

This consensus conference was conducted according to the American College of Cardiology (ACC)/American Heart Association (AHA) standards for development of clinical practice guidelines. The Steering Committee collated all published studies of OPCAB versus CCAB through May 2004 and developed six questions central to controversies surrounding OPCAB surgery in mortality, morbidity, and resource utilization. For mixed-risk patient populations, meta-analysis of 37 randomized clinical trials (3,369 patients, Level A) reported across a total of 53 papers, and two meta-analyses of nonrandomized trials (Level B) comparing OPCAB versus CCAB were identified. For high-risk patient populations, we performed a meta-analysis of 3 randomized and 42 nonrandomized trials (26,349 patients, Level B).

Conclusion

Meta-analysis of Level A and B evidence provided the basis for the following consensus statements in patients undergoing surgical myocardial revascularization: (1) OPCAB should be considered a safe alternative to CCAB with respect to risk of mortality [Class I, Level A]; (2) With appropriate use of modern stabilizers, heart positioning devices, and adequate surgeon experience, similar completeness of revascularization and graft patency can be achieved [Class IIa, Level A]; (3) OPCAB is recommended to reduce perioperative morbidity [Class I, Level A]; (4) OPCAB may be recommended to minimize midterm cognitive dysfunction [Class IIa, Level A]; (5) OPCAB should be considered as an equivalent alternative to CCAB in regard to quality of life [Class I, Level A]; (6) OPCAB is recommended to reduce the duration of ventilation, ICU and hospital stay, and resource utilization [Class I, Level A]; (7) OPCAB should be considered in high-risk patients to reduce perioperative mortality, morbidity, and resource utilization [Class IIa, Level B].

Off-pump versus on-pump complete coronary artery bypass grafting: Comparison of the effects on the renal damage in patients with renal dysfunction

BACKGROUND

We aimed to compare off-pump technique with on-pump technique on renal function in patients with nondialysis-dependent renal dysfunction who underwent coronary artery bypass grafting.

METHODS

The 94 patients with renal dysfunction undergoing isolated coronary artery bypass grafting were retrospectively analyzed. No patient was receiving dialysis. Patients were randomly assigned to conventional revascularization with cardiopulmonary bypass and beating heart. Both groups were compared in terms of renal dysfunction parameters and dialysis requirement. The logistic regression models were constructed to identify risk factors associated with dialysis requirement.

RESULTS

Renal dysfunction requiring dialysis developed in 9 patients in the on-pump group. The 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. Cardiopulmonary bypass is significant as independent predictor for the development of postoperative dialysis.

CONCLUSION

These results suggest that off-pump coronary revascularization offers a superior renal protection and has a significantly lower risk for renal complications in patients with nondialysis-dependent renal dysfunction when compared with conventional coronary revascularization with cardiopulmonary bypass.

Morphologic Evaluation of the Mitral Annulus During Displacement of the Heart in Off-Pump Coronary Artery Bypass Surgery

OBJECTIVE

To evaluate the morphologic changes of the mitral annulus using 3-dimensional transesophageal echocardiography during heart displacement to expose the anastomosis site in off-pump coronary artery bypass surgery (OPCAB).

DESIGN

Prospective case series.

SETTING

Single center, university hospital.

PARTICIPANTS

The study comprised 34 consecutive patients who underwent OPCAB of the left circumflex artery (LCX) and the right coronary artery (RCA).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Mitral annulus parameters were measured using the Mitral Valve Quantification program after sternotomy (physiologic position) and during displacement of the heart to expose the LCX (LCX position) and the RCA (RCA position). The height of the mitral annulus was significantly lower in the LCX (5.76 ± 0.90 mm) and RCA (5.92 ± 0.97 mm) positions than in the physiologic position (6.96 ± 0.99 mm; both p < 0.0001). The percent change in the height of the mitral annulus was significantly greater in the mitral regurgitation group than in the mitral regurgitation nondeterioration group when in the LCX (-16.3% ± 6.0% v -11.9% ± 3.3%, p = 0.0203) and RCA (-16.9% ± 6.3% v -12.1% ± 3.8%, p = 0.0207) positions. The anteroposterior and intercommissural diameters, annulus perimeter, and surface area of the mitral annulus did not differ significantly among all heart positions.

CONCLUSIONS

The mitral annulus flattened and lost its saddle shape without expanding while in the LCX and RCA positions. The greater percent change in the height of the mitral annulus may aggravate mitral regurgitation.

Suction catheter for enhanced control and accuracy of transseptal access

AIMS

Percutaneous structural heart therapies, such as mitral value repair, require site-specific transseptal access (TSA). This can be challenging for interventional cardiologists. We describe a TSA catheter (TSAC) that utilises suction for enhanced control and puncture accuracy. Here, we aim to evaluate the safety and efficacy of the device.

METHODS AND RESULTS

Ex vivo interatrial septum preparations were dissected from swine (n=8) and diseased human hearts (n=6) to quantify TSAC suction and needle puncture force. TSAC suction was 6.5-fold greater than the opposing needle puncture force, and thus provides sufficient stabilisation for punctures. The safety and efficacy of TSAC was evaluated in a chronic mitral regurgitation swine model (n=10) and compared to a conventional TSA device. MR was induced by disrupting one to three mitral chordae tendineae, and the progression of heart disease was followed for three weeks. During device testing, procedure time and fluoroscopy exposure were not statistically different between devices. TSAC reduced septal displacement from 8.7±0.30 mm to 3.60±0.19 mm (p<0.05) and improved puncture accuracy 1.75-fold.

CONCLUSIONS

TSAC provides controlled TSA and improves puncture accuracy, while maintaining procedure time and workflow. These findings provide a strong rationale for a first-in-man study to demonstrate the clinical utility of the device.

Stroke Rate of Off-pump Coronary Artery Bypass; Aortocoronary Bypass Versus in-Situ Bypass

Off-pump coronary artery bypass (OPCAB) using in-situ grafts does not require aortic manip ulation, and it is theoretically free from the risk of stroke. Because of the limited availability of in-situ grafts, aortocoronary bypass has been conducted in addition to in-situ grafting. In this paper, the authors prospectively investigated whether or not on aortocoronary bypass increases the incidence of stroke after off-pump bypass. Perioperative data were collected prospectively from patients who underwent isolated off-pump bypass at their hospital group between March 1997 and February 2002. The patients were divided into 2 groups; group AC (patients with at least 1 aortocoronary bypass, n = 280) and group IS (patients with all in-situ grafts, n = 234). Patients with 3-vessel disease more frequently underwent aortocoronary bypass and patients with a history of stroke, calcified ascending aorta, or renal failure more often underwent in-situ graft. The number of distal anastomoses was greater in group AC (3.5 ± 1.0) than in group IS (2.7 ± 1.1), p < 0.0001. Patient recovery and complication rates were similar, including the occurrence of postoperative stroke: 3.0% (7/234) in group IS vs 0.7% (2/280) in group AC, p=0.051, NS. The graft patency and remote results were not significantly different between the 2 groups. Side clamping of the aorta used in off-pump aortocoronary bypass does not increase the risk of postoperative strokes compared to in-situ bypass. Postoperative stroke after OPCAB may depend on the patient's preoperative comorbidities.

Effect of Pre-operative Angiotensinconverting Enzyme Inhibitors on Haemodynamic Parameters and Vasoconstrictor Requirements in Patients Undergoing Off-pump Coronary Artery Bypass Surgery

The effects of pre-operative angiotensin-converting enzyme inhibitor (ACEI) treatment on haemodynamic status and vasoconstrictor requirements during off-pump coronary artery bypass surgery (OPCAB) were studied. Eighty patients selected for OPCAB were divided into those who had been treated with ACEIs for 4 weeks or more pre-operatively (ACEI group) (n = 43) and those who had not been treated with ACEIs (control group) (n = 37). Noradrenaline was infused during the operation when the mean systemic arterial pressure (SAP) fell below 60 mmHg. No significant differences in the haemodynamic parameters measured were detected between the two groups, except for cardiac output, which was found to be significantly greater in the control group. During anastomosis of the obtuse marginal branch of the left circumflex artery (OM), a significantly larger amount of noradrenaline was required by the ACEI group compared with the control group. In conclusion, pre-operative treatment with ACEIs significantly increased the amount of vasoconstrictor necessary to maintain the target SAP during OM anastomosis during OPCAB.

The effect of milrinone infusion on right ventricular function during coronary anastomosis and early outcomes in patients undergoing off-pump coronary artery bypass surgery

Background

During coronary anastomosis in off-pump coronary artery bypass surgery (OPCAB), hemodynamic alternations can be induced by impaired diastolic function of the right ventricle. This study was designed to examine the effect of milrinone on right ventricular function and early outcomes in patients undergoing OPCAB.

Methods

Forty patients undergoing OPCAB were randomly assigned in a double-blind manner to receive either milrinone (milrinone group, n = 20) or normal saline (control group, n = 20). Hemodynamic variables were measured after pericardiotomy (T1), 5 min after stabilizer application for anastomosis of the left anterior descending coronary artery (LAD, T2), the obtuse marginalis branch (OM, T3), the right coronary artery (RCA, T4), 5 min after sternal closure (T5), and after ICU arrival. The right ventricular ejection fraction (RVEF) and right ventricular volumetric parameters were also measured using the thermodilution technique. For evaluation of early outcomes, the 30-day operative mortality and morbidity risk models were used.

Results

There was no significant difference in hemodynamic variables, including mean arterial pressure, between the 2 groups, except for the cardiac index and RVEF. The cardiac index and RVEF were significantly greater at T3 in the milrinone group than in the control group.

Conclusions

Continuous infusion of milrinone demonstrated a beneficial effect on cardiac output and right ventricular function in patients undergoing OPCAB, especially during anastomosis of the graft to the OM artery, and it had no adverse effect on early outcomes.

Off-Pump versus On-Pump Coronary Artery Bypass Procedures: Postoperative Renal Complications in an Asian Population

Introduction: Diabetes and habitual smoking cause advanced coronary artery disease (CAD) in Asian patients at a younger age. No definite data exist as to whether off-pump (OPCAB) is better than conventional on-pump coronary artery bypass grafting (CCAB) in terms of postoperative renal complications. Thus, we aimed to compare the renal outcomes of on-pump and off-pump coronary artery bypass grafting (CABG) on our patients, which constituted a predominantly Asian population. Materials and Methods: A cohort of 395 patients following CCAB were compared with 293 patients who underwent OPCAB. Baseline demographics, comorbidities, intraoperative data, intensive care unit stay, number of grafts, New York Heart Association (NYHA) score, American Society of Anesthesiologists (ASA) score, EuroSCORE risk assessment model, and postoperative complications particularly renal, were collected and analysed. Results: The off-pump group consisted of significantly older patients with higher Canadian Cardiovascular Society (CCS) and ASA scores. Additionally, the off-pump group involved a significantly greater number of smokers and chronic obstructive pulmonary disease (COPD) patients. Other demographic parameters were not different between the groups. Postoperative investigations showed a significantly elevated serum creatinine (100.3 ± 42.5 vs 127.6 ± 114.2 μmol/L; off-pump vs on-pump; P = 0.039) and urea levels (5.9 ± 3.1 vs 10.6 ± 15.6 mg/dL; off-pump vs on-pump; P = 0.006) in the on-pump group. Moreover, there was a high tendency towards a higher rate of renal dysfunction associated death in this group. Conclusions: OPCAB is a safe and equally efficient operative method compared to CCAB, and has a significant lower risk for postoperative renal complications as a treatment modality for surgical coronary revascularisation. Key words: Cardiopulmonary bypass, Renal dysfunction

Temporal pattern of strokes after on-pump and off-pump coronary artery bypass graft surgery

BACKGROUND

The incidence of strokes has not decreased after coronary artery bypass graft surgery (CABG). The purpose of this study is to identify incidence, risk factors, and temporal pattern of strokes after on-pump and off-pump CABG.

METHODS

We analyzed 2,516 consecutive patients who underwent first elective isolated CABG. The primary endpoint was strokes within 30 days. The temporal onset of the deficits was classified by consensus as either an "early stroke," which is present just after emergence from anesthesia, or a "delayed stroke," which is present after first awaking from surgery without a neurologic deficit.

RESULTS

More than half of strokes (29 of 46; 63%) were delayed strokes. Patients undergoing off-pump CABG had significantly lower risk of early stroke (0.1% versus 1.1%, p = 0.0009), whereas the incidence of delayed strokes was not different significantly (0.9% versus 1.4%, p = 0.3484) between patients undergoing on-pump and off-pump CABG. In multivariate analyses, undergoing off-pump CABG was an independent protective factor for all strokes (relative risk 0.29, 95% confidence interval: 0.14 to 0.56, p = 0.0005) and early strokes (relative risk 0.05, 95% confidence interval: 0.003 to 0.24, p < 0.0001), but it was not an independent protective factor for delayed strokes (relative risk 0.54, 95% confidence interval: 0.24 to 1.17, p = 0.1210).

CONCLUSIONS

Undergoing off-pump CABG reduces the incidence of perioperative stroke mainly by minimizing early strokes; however, the risk of delayed strokes is not different between patients undergoing on-pump and off-pump CABG.

Influence of intracoronary shunt on myocardial damage: a prospective randomized study

OBJECTIVE

We aimed to evaluate whether surgical intracoronary shunt protects myocardium in patients with moderate left ventricular dysfunction (MLVD).

METHODS

Thirty-nine patients consisted the shunt group and 43 patients consisted the shuntless group. Troponin I, CK, and CK-MB were measured preoperatively, and at 6 and 24h postoperatively. Cardiac enzymes, rate of postoperative atrial fibrillation (AF) and third month ejection fraction (EF) were compared between the groups.

RESULTS

There were no significant differences between the groups for preoperative troponin I, CK, CK-MB, and postoperative CK levels (at 6 and 24h). Postoperative troponin I and CK-MB levels were significantly lower in the shunt group (p<0.001). Although preoperative EF of the patients were not significantly different between groups, the third month EF were significantly increased in both groups, and this increment was significantly higher in the shunt group than the shuntless group. One patient (2.3%) died in the shuntless group whereas there was no death in the shunt group.

CONCLUSION

Intracoronary shunt has protective effects on myocardium in patients with moderate left ventricular dysfunction.

A coronary active perfusion system for off-pump coronary artery bypass grafting in an experimental porcine model: the relationship between flow rate and myocardial function

We developed a coronary active perfusion system (synchronized arterial flow ensuring system [SAFE-System]) to prevent myocardial ischemia during distal anastomosis in off-pump coronary artery bypass grafting (CABG). The purpose of this study was to identify the relationship between the flow rate of the SAFE-System and myocardial function. Studies were performed on pigs, which were divided into five groups: external shunt perfusion group (group A, n = 6); 0.1 mL/beat flow rate for the SAFE-System group (group B, n = 6); 0.2 mL/beat flow rate group (group C, n = 6); 0.3 mL/beat flow rate group (group D, n = 6); and 0.4 mL/beat flow rate group (group E, n = 6). Regional myocardial blood flow and left ventricular function were monitored for 30 min. The regional myocardial blood flow in group A was severely decreased (P < 0.001), and was significantly lower than in the other groups (P < 0.001). The slope of the end-systolic pressure-volume relationship, and the slope of the preload recruitable stroke work relationship in groups A, D, and E were lower than in groups B and C. As compared with the use of a passive external shunt, a coronary active perfusion system provides adequate myocardial blood flow and hemodynamics. It was possible to maintain left ventricular function when using 0.1 or 0.2 mL/beat flow rate. The use of a coronary active perfusion system appears to make the off-pump CABG procedure safer and may increase the application of off-pump bypass grafting.

[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 versus on-pump coronary artery bypass graft surgery: differences in short-term outcomes and in long-term mortality and need for subsequent revascularization

BACKGROUND

Off-pump coronary artery bypass graft surgery (OPCAB) has been performed for many years, but its use is increasing in frequency, and it remains an open question whether OPCAB is associated with better outcomes than on-pump coronary artery bypass graft (CABG) surgery.

METHODS AND RESULTS

New York State patients who underwent either OPCAB with median sternotomy (13 889 patients) or on-pump CABG surgery (35 941 patients) between 2001 and 2004 were followed up via New York databases. Short- and long-term outcomes were compared after adjustment for patient risk factors and after patients were matched on the basis of significant predictors of type of CABG surgery. OPCAB had a significantly lower inpatient/30-day mortality rate (adjusted OR 0.81, 95% confidence interval [CI] 0.68 to 0.97), lower rates for 2 perioperative complications (stroke: adjusted OR 0.70, 95% CI 0.57 to 0.86; respiratory failure: adjusted OR 0.80, 95% CI 0.68 to 0.93), and a higher rate of unplanned operation in the same admission (adjusted OR 1.47, 95% CI 1.01 to 2.15). In the matched samples, no difference existed in 3-year mortality (hazard ratio 1.08, 95% CI 0.96 to 1.22), but OPCAB patients had higher rates of subsequent revascularization (hazard ratio 1.55, 95% CI 1.33 to 1.80). The 3-year OPCAB and on-pump survival rates for matched patients were 89.4% and 90.1%, respectively (P=0.20). For freedom from subsequent revascularization, the respective rates were 89.9% and 93.6% (P<0.0001).

CONCLUSIONS

OPCAB is associated with lower in-hospital mortality and complication rates than on-pump CABG, but long-term outcomes are comparable, except for freedom from revascularization, which favors on-pump CABG.

Deep pericardial suture vs apical suction for off-pump bypass grafting

Hemodynamic changes during heart luxation and stabilization are major problems in off-pump coronary artery bypass surgery. The hemodynamic effects of an apical suction device were compared with those of the classic posterior pericardial suture in 45 patients with multivessel coronary disease undergoing off-pump coronary artery bypass. Mean age was 63.78 +/- 8.11 years; 31 patients were male and 14 were female. Transesophageal Doppler echocardiography was used for hemodynamic monitoring. All hemodynamic parameters were significantly better when the apical suction device was used to position the heart for anastomoses on the posterior descending and circumflex arteries.

Living with off-pump coronary artery surgery: evolution, development, and clinical potential for coronary heart disease patients

The enormous progress in interventional cardiology during the last 10 years has resulted in a major change in the spectrum of patients referred for coronary bypass surgery. These patients are older and sicker and frequently have had previous percutaneous coronary interventions. Consequently, cardiac surgery is responding by adding new surgical techniques: off-pump open-chest coronary bypass surgery (OPCAB), minithoracotomy bypass surgery, videothoracoscopic (robotic) procedures, etc. Several registries published to date have proved OPCAB to be safe and clinically effective. Randomized studies and meta-analysis research in this field provide scientific support and suggest that myocardial, renal, and neurological functions, amongst others, are better preserved by OPCAB than by classic techniques that use a cardiopulmonary bypass pump (CPB). Moreover, avoidance of CPB yields significantly reduced oxidative stress and systemic inflammatory response. This results in higher safety for ischemic heart disease patients undergoing revascularization, thus offsetting the propensity to lower costs. The present review examines the physiological advantages and clinical outcomes of this simple mode of myocardial revascularisation and evaluates the wider implications arising from its evolution.

Surgical revascularization for acute coronary syndrome

OBJECTIVE

The purpose of this study was to evaluate the adequate timing of coronary artery bypass grafting (CABG) for acute coronary syndrome (ACS).

METHODS

In our institution, emergency CABG has been avoided when possible for ACS patients favoring stabilization with medical therapies, including intra-aortic balloon pumping or percutaneous coronary intervention. After thorough preoperative examinations, an urgent CABG is performed. A total of 67 patients with ACS underwent CABG, comprised of 33 patients receiving an emergency CABG (emergent group: E-G) and 34 patients receiving an urgent CABG (urgent group: U-G). The early and long-term results were evaluated retrospectively.

RESULTS

Preoperatively, the incidences of acute myocardial infarction and cardiogenic shock were significantly higher in E-G. No significant differences were found in the intraoperative factors except for the number of distal anastomoses (2.5 in E-G vs. 3.1 in U-G, p=0.01). The hospital mortality was 9.1% in E-G, and 2.9% in U-G, with no significant difference between the groups. Moreover, no patient in U-G necessitated emergency CABG while waiting for surgery. The patency rate of the grafts was 100% in E-G, and 96.2% in U-G. The 5-year survival rate excluding in-hospital death was 80.3% in E-G, and 78% in U-G (p>0.05). The 5-year cardiac event-free rate was 80.3% in E-G, and 80.9% in U-G (p>0.05).

CONCLUSION

An emergency CABG can be reserved for ACS patients when symptoms and hemodynamic state are stabilized with medical therapies. Improvements in long-term results can be expected after high quality and complete surgical revascularization.

[Off-pump coronary artery bypass: analysis of 1080 patients]

A consecutive cohort including 1080 patients undergoing "off-pump" myocardial revascularization was reviewed. An average of 2.22 bypass/patients was performed. The death-rate during the first 30 days after surgery was 0.65%. Four cases needed cross-over to on-pump. The postoperative events were: need of inotropic drugs (2.7%), atrial fibrillation (12.4%), myocardial infarction (6.6%). The extubation was performed before the first postoperative 24 h in 91.9% of cases. The majority of patients was discharged from hospital before 8 days after surgery. Off pump coronary artery bypass surgery exhibit good results for most of the patients even if they present multiple vessel disease and high operating risk.

Off-pump coronary artery bypass grafting reduces postoperative neurologic complications

OBJECTIVE

Complications occurring after coronary artery bypass graft (CABG) surgery, particularly neurologic damage, have been mainly correlated with the use of cardiopulmonary bypass (CPB). The aim of this work was to compare postoperative outcomes of patients undergoing CABG surgery, with or without the use of CPB, focusing on neurologic events.

DESIGN

Observational study.

SETTING

University tertiary care hospital.

PARTICIPANTS

Two thousand seven hundred and forty consecutive patients who underwent CABG surgery in the period January 1998 to January 2003.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

For 738 patients, the operation was performed off-pump (OP group), and for 2002 patients CPB was used (CPB group). OP and CPB groups were compared with regard to preoperative status, anesthetic management, and postoperative outcomes, by means of univariate and multivariate analyses. Surgeons' propensity to operate off-pump was based on patients' age, renal conditions, and hemodynamics. Univariate and multivariate analyses showed that CPB was associated with a higher incidence of type I neurologic events compared with OP technique (2.1% versus 0.9%, odds ratio [OR]: 2.6, 95% confidence interval [CI], 1.2-5.9). A history of previous stroke (OR: 2.7, 95% CI, 1.2-5.9) and advanced age (OR: 1.06 per year, 95% CI, 1.02-1.09) were additional independent predictors of postoperative type I neurologic events.

CONCLUSIONS

In the authors' experience, off-pump CABG surgery offers some benefits compared with CPB in respect to major neurologic complications.

Emergency conversion to cardiopulmonary bypass during attempted off-pump revascularization results in increased morbidity and mortality

OBJECTIVE

We sought to evaluate outcomes and predictors of emergency conversion to cardiopulmonary bypass during attempted off-pump coronary bypass surgery.

METHODS

From January 1999 through July 2002, 1678 consecutive isolated coronary artery bypass operations were performed at Lenox Hill Hospital, with the intention to treat all patients with off-pump coronary bypass surgery. Fifty (2.97%) patients required urgent conversion to cardiopulmonary bypass. All the preoperative, intraoperative, and postoperative variables were collected and analyzed in accordance with the New York State Cardiac Surgery Reporting System. Multivariate regression analysis was performed to determine predictors for conversion.

RESULTS

In-hospital mortality and major morbidity were significantly lower in the nonconverted group compared with the converted patients (mortality: 1.47% [n = 24] vs 12% [n = 6], P = .001; stroke: 1.1% [n = 18] vs 6% [n = 3], P = .02; renal failure: 1.23% [n = 20] vs 6% [n = 3], P = .02; deep sternal wound infection: 1.54% [n = 25] vs 8% [n = 4], P = .009; respiratory failure: 3.75% [n = 61] vs 28% [n = 14], P < .0001; nonconverted vs converted patients, respectively). The annual incidence of conversion decreased during the study period. There was a significant reduction in the incidence of conversion after routine use of a cardiac positioning device to performing lateral and inferior wall grafts (4.2% [n = 27] vs 2.3% [n = 23], P = .04). None of the preoperative variables were independent predictors of conversion on multivariate regression analysis.

CONCLUSIONS

Because emergency conversion to cardiopulmonary bypass during attempted off-pump coronary bypass surgery results in significantly higher morbidity and mortality, studies comparing off-pump coronary bypass surgery with conventional coronary artery surgery should include converted patients in the off-pump group. In our experience, emergency conversion is an unpredictable event. The incidence of conversion decreases with increasing experience of surgeons in performing off-pump coronary surgery and use of a cardiac positioning device.

[Off-pump versus on-pump coronary artery bypass surgery. Comparison of 270 case-matched elderly patients]

INTRODUCTION

Off-pump versus on-pump coronary artery bypass surgery: it still remains a matter of debate which method results in a lower incidence of perioperative morbidity and mortality. This case-matched study evaluates the outcome of elderly patients in both groups.

METHODS

All patients aged 75 and older, who underwent CABG from 1998 to 2002, were examined retrospectively. They were matched according to Euroscore and the number of diseased vessels. The Student's t-test and chi-square test were used where appropriate.

RESULTS

270 CABG patients were considered: 135 off-pump and 135 on-pump patients. Mean age was 78.4 +/- 3.1 versus 77.5 +/- 2.9 years, respectively. EuroSCORE was 7.11 +/- 2.3 in both groups; number of distal anastomoses per patient 1.7 +/- 0.74 versus 2.6 +/- 0.63 (p < 0.001), operation time 138 versus 177 minutes (p < 0.001). There were no significant differences in postoperative complications including hospital mortality 3.0 versus 3.7%, renal failure 8.9 versus 12.1% (new onset), acute myocardial infarction 1.5 versus 4.4% and cerebral events 0 versus 1.5%, respectively. The number of transfused packed cells was 2.6 +/- 2.8 versus 4.6 +/- 5.3 (p < 0.001). Intubation time and ICU stay were similar in both groups.

CONCLUSION

OPCAB is not associated with a reduction of perioperative mortality and morbidity in patients aged 75 and older.

Ninety-degree anterior cardiac displacement in off-pump coronary artery bypass grafting: the Starfish cardiac positioner preserves stroke volume and arterial pressure

PURPOSE

In off-pump coronary surgery through sternotomy, exposure of posterior circumflex branches causes circulatory deterioration in both patients and pigs. We assessed cardiac pump function when displacing the pig heart anteriorly with a suction cardiac positioner.

DESCRIPTION

Six pigs (+/-80 kg) underwent sternotomy for hemodynamic instrumentation using catheter-tipped manometers and paced at 80 beats/min. Ultrasound flow probes were placed around the aorta and proximal coronary arteries. The heart was retracted anteriorly to 90 degrees with the Starfish cardiac positioner attached to the apex by means of suction (-400 mm Hg). Retraction was guided by cardiac output monitoring.

EVALUATION

Anterior displacement to 90 degrees facilitated full exposure of posterior arteries. Stroke volume and mean arterial pressure decreased to 94% +/- 13% (mean +/- SD, p = 0.135) and 95% +/- 13% (p = 0.09) of control values, respectively. Right and left ventricular end-diastolic pressure increased to 129% +/- 37% (p = 0.009) and to 128% +/- 57% (p = 0.235), respectively. Coronary flow remained unchanged. Additional 15-degree head-down positioning increased stroke volume to 113% +/- 17% (p = 0.015) and mean arterial pressure to 113% +/- 25% (p = 0.087) at the expense of further increased right and left ventricular end-diastolic pressure (186% +/- 63%, p < 0.001 and 157% +/- 49%, p < 0.001, respectively).

CONCLUSIONS

When lifting the porcine heart ninety degrees anteriorly, the Starfish cardiac positioner facilitated exposure of posterior branches and, when guided by cardiac output, preserved stroke volume and arterial pressure.

Haemodynamic effects of a milrinone infusion without a bolus in patients undergoing off-pump coronary artery bypass graft surgery

The haemodynamic effects of a continuous infusion of milrinone without an initial bolus dose were evaluated in patients undergoing off-pump coronary artery bypass graft surgery. After internal mammary artery harvest, milrinone 0.5 microg.min(-1).kg(-1) (29 patients) or a normal saline infusion (33 patients) was started and continued until all graft anastomoses were completed. Haemodynamic variables were recorded before application of the tissue stabiliser, at 1, 3, 5 and 10 min after the application of the stabiliser, and after its removal. The administration of a milrinone infusion was associated with a smaller decrease in cardiac output and mixed venous oxygen saturation during all the coronary artery anastomoses, with no severe complications and a decreased dose of norepinephrine infused to maintain systemic arterial pressure.

Coronary Bypass Surgery Performed off Pump Does Not Result in Lower In-Hospital Morbidity Than Coronary Artery Bypass Grafting Performed on Pump

BACKGROUND

There is increasing evidence that cardiopulmonary bypass (CPB) may be responsible for the morbidity associated with coronary artery bypass grafting (CABG) surgery. Recent developments in cardiac stabilization devices have made CABG without CPB feasible. However, there is conflicting evidence to date from published trials comparing outcomes between CABG performed with and without CPB, with some trials indicating an advantage to the avoidance of CPB and others showing little benefit.

METHODS AND RESULTS

In a single-center randomized trial, 300 patients requiring CABG surgery at a single institution were prospectively randomized to have the procedure performed with CPB (n=150) or on the beating heart (n=150). Exclusion criteria for the trial included emergency procedure, concomitant major cardiac procedures, ejection fraction <30%, and reoperation. In-hospital outcomes were analyzed on an intention-to-treat basis. A mean of 3.0+/-0.9 grafts were performed in the CPB group compared with 2.8+/-0.9 grafts in the beating-heart group (P=0.06). There were no significant differences between the CPB group and the beating-heart group in mortality (0.7% versus 1.3%; P=1.0), transfusion (8.7% versus 9.3%), perioperative myocardial infarction (0.7% versus 2.7%; P=0.37), permanent stroke (0% versus 1.3%; P=0.50), new atrial fibrillation (32% versus 25%; P=0.20), and deep sternal wound infection (0.7% versus 0%; P=1.0). The mean time to extubation was 4 hours, the mean stay in the intensive care unit was 22 hours, and the median length of hospitalization was 5 days in both groups (P=NS).

CONCLUSIONS

In contrast to published trials, we were unable to demonstrate any advantage with CABG performed without CPB in terms of patient morbidity. Excellent results can be obtained with either surgical approach.

A comparison of short- and long-term outcomes after off-pump and on-pump coronary artery bypass graft surgery with sternotomy

OBJECTIVES

This study was designed to compare in-hospital mortality and complications and three-year mortality and revascularization for off-pump and on-pump coronary artery bypass graft (CABG) surgery after adjusting for patient risk.

BACKGROUND

The use of off-pump CABG surgery has increased tremendously in recent years, but little is known about its long-term outcomes relative to on-pump CABG surgery, and most studies have been very small.

METHODS

Short- and long-term outcomes (inpatient mortality and complications, three-year risk-adjusted mortality, and mortality/revascularization) were explored for patients who underwent off-pump CABG surgery (9135 patients) and on-pump CABG surgery (59044 patients) with median sternotomy from 1997 to 2000 in the state of New York.

RESULTS

Risk-adjusted inpatient mortality was 2.02% for off-pump versus 2.16% for on-pump (p = 0.390). Off-pump patients had lower rates of perioperative stroke (1.6% vs. 2.0%, p = 0.003) and bleeding requiring reoperation (1.6% vs. 2.2%, p < 0.001) and higher rates of gastrointestinal bleeding, perforation, or infarction (1.2% vs. 0.9%, p = 0.003). Off-pump patients had lower postoperative lengths of stay (median 5 days vs. 6 days, p < 0.001). On-pump patients had higher three-year survival (adjusted risk ratio [RR] =1.086, p = 0.045) and higher freedom from death or revascularization (adjusted RR = 1.232, p < 0.001). When analyses were limited to 1999 to 2000, the two-year adjusted hazard ratio for survival was not significant (adjusted RR = 0.99, p = 0.81).

CONCLUSIONS

On-pump patients experience better long-term survival and freedom from revascularization than off-pump patients. However, the survival benefit from on-pump procedures was no longer present in the last two years of the study.

Initial experience with a new right ventricular support device for beating heart surgery

OBJECTIVE

Device supported beating heart surgery has been advocated to extend patient selection criteria for off-pump surgery. This article reports the initial experimental and clinical results with a novel paracardial right ventricular support device.

METHODS

Preclinical experiments were performed in two pigs. Ten elective patients with triple vessel disease were subjected to beating heart coronary artery bypass grafting surgery during right ventricular support by the paracardial device. Measurements included intraoperative hemodynamics during cardiac tilting, perioperative left ventricular ejection fraction (LVEF), hemolysis parameters, mortality and major morbidity events.

RESULTS

A mean of 3.2 +/- 0.2 distal anastomoses per patient were performed. Mean arterial pressure and central venous oxygen saturation remained stable during cardiac tilting. Perioperative LVEF did not vary significantly. Sixty-day mortality and postoperative infarction rate were 0%. Functional Canadian Cardiovascular Society class at 6 days after surgery was 1.2 +/- 0.1 vs. 3.3 +/- 0.2 pre-operatively.

CONCLUSION

In this initial clinical experience, application of the novel paracardial right ventricular support device proved to be safe and efficient.

Innovative surgical strategies: Minimally invasive CABG and off-pump CABG

Minimally invasive coronary artery bypass grafting (CABG) and off-pump coronary artery bypass grafting (OPCAB) have made up a significant facet of the recent attempts of surgical myocardial revascularization to evolve. Driven by an effort to limit the deleterious effects of cardiopulmonary bypass (CPB), along with a response to both the growing interests in performing procedures through smaller incisions and the successes of catheter-based therapies, these therapeutic options have found themselves moving into the future by resurrecting their past. Minimally invasive CABG is the procedure by which coronary grafting is performed through a small anterior thoracotomy, without the use of CPB. Although feasible, the inability to offer a more thorough degree of revascularization has limited the applicability of this procedure and, therefore, accounts for its overall minor contribution to the number of coronary revascularizations performed annually. Conversely, as the technical feasibility of performing complete revascularization without CPB has been achieved with OPCAB, its place as a mode of therapy remains uncertain. Several clinical trials have been performed to date with only a few being done in a prospective, randomized fashion. From this data has come a mix of information regarding either improvements or, at a minimum, no change in the rate of complications between CABG with, and without, CPB, while at the same time maintaining equivalent short-term graft patencies. The question remains, however, to which patient population is this approach to CABG optimal? Our practice has largely reserved OPCAB for those patients in whom manipulation of the aorta is considered not feasible due to severe calcification or in "high-risk" patients who are felt to be unable to tolerate the adverse physiologic effects of CPB. This makes up approximately 15% of our CABG population, roughly equal to the national average, with the remaining patients being revascularized with the assistance of CPB.

Automated distal coronary bypass with a novel magnetic coupler (MVP system)

OBJECTIVE

We sought to assess the feasibility of performing sutureless distal coronary artery bypass anastomoses with a novel magnetic coupling device.

METHODS

From May 2000 to April 2001, single-vessel side-to-side coronary artery bypass grafting on a beating heart was performed in 39 domestic white pigs (35-60 kg) without the use of mechanical stabilization, shunts, or perfusion bridges. Animals were divided into 2 groups. Seventeen pigs underwent right internal thoracic artery to right coronary artery bypass grafting through a median sternotomy (group 1) with a novel magnetic vascular positioning system (MVP system; Ventrica, Inc, Fremont, Calif). Twenty-two pigs underwent left internal thoracic artery to left anterior descending artery grafting with the MVP anastomotic device through a left anterior minithoracotomy (group 2). This system consists of 2 pairs of elliptical magnetic implants and a deployment device. One pair of magnets forms the anastomotic docking port within the graft; the other pair forms an identical anastomotic docking port within the target vessel. The anastomosis is created when the 2 docking ports magnetically couple. Anastomotic patency was evaluated by means of angiography during the first postoperative week and at 1 month. Histologic studies were performed at different time points as late as 6 months.

RESULTS

Right internal thoracic artery to right coronary artery anastomoses and left internal thoracic artery to left anterior descending artery anastomoses were successfully performed with the system in all animals. The self-adherent and self-aligning properties of the implants allowed for immediate and secure approximation of the arteries (total anastomotic time between 2-3 minutes). Anastomoses were constructed without a stabilization platform. Five nondevice-related deaths occurred postoperatively. One-week angiography, performed in 35 surviving animals, showed a patent graft and anastomosis in all cases. The patency rate at 1 month was 97% (33/34). Histologic studies as late as 6 months demonstrated neointimal coverage of the magnets without any significant luminal obstruction. Histology also confirmed the presence of viable tissue between magnets.

CONCLUSION

The MVP anastomotic system uses magnetic force to create rapid and secure distal coronary artery anastomoses, which might facilitate minimally invasive and totally endoscopic coronary artery bypass surgery.

Limitations for manual and telemanipulator-assisted motion tracking—implications for endoscopic beating-heart surgery

BACKGROUND

Surgical performance is limited by human factors. Beating-heart surgery requires full dexterity and motion tracking. Currently techniques for total endoscopic beating-heart bypass grafting using telemanipulation systems are being developed. The aim of this study was to assess the limitations for manual and telemanipulator-assisted motion tracking using the da Vinci telemanipulator system.

METHODS

To simulate beating-heart conditions an endoscopic trainer was developed. Twenty subjects were asked to touch targets manually and with telemanipulator assistance with different patterns of increasing index of difficulty (resting model, unstabilized, and stabilized model with a frequency of 35, 60, and 90 beats per minute). In addition one task was performed using different scaling ratios on a resting model. The times between hits as well as errors were electronically recorded.

RESULTS

There was no significant impact of various frequencies and amplitudes for manual tracking. The average values for the delay (k(m)[ms]) and information-processing (c(m) [ms/bit]) constants for the manual tasks were 201 ms and 86 ms/bit respectively. Both the delay constant (k(t) = 630 ms; p < 0.0005) and the information-processing constant (c(t) = 250 ms/bit; p < 0.0005) were increased for the telemanipulator-assisted tasks at rest. When working on moving targets telemanipulator-assisted tracking required significantly more time and led to more errors. At a frequency of 90 beats per minute telemanipulator-assisted tracking became more difficult.

CONCLUSIONS

Endoscopic beating-heart bypass grafting requires optimal stabilization to avoid inaccuracies due to incomplete motion tracking. At higher frequencies telemanipulator-assisted tracking became more difficult, demonstrating the technical limits of current telemanipulator technology.

Off-pump coronary artery bypass graft surgery: the incidence of postoperative atrial fibrillation

Atrial fibrillation (AF) occurs in one quarter to one third of patients after coronary artery bypass graft surgery (CABG). Conventional CABG uses cardiopulmonary bypass, a process that is itself associated with a systemic vascular inflammatory response that contributes to postoperative morbidity. The avoidance of cardiopulmonary bypass is associated with a significant reduction in the inflammatory response and in the release of markers of myocardial necrosis when compared with conventional CABG. There is speculation that off-pump CABG may reduce the incidence of postoperative AF through reduced trauma, ischaemia, and inflammation. Current data, however, do not emphatically answer the question of whether the incidence of post-CABG AF is reduced by off-pump surgery. The evidence from both observational and randomised studies is conflicting and many studies have weaknesses in design, conduct, or interpretation. It remains an attractive hypothesis that postoperative AF is reduced by off-pump CABG but more robust data are required.

Off-pump coronary artery bypass grafting provides complete revascularization with reduced myocardial injury, transfusion requirements, and length of stay: a prospective randomized comparison of two hundred unselected patients undergoing off-pump versus conventional coronary artery bypass grafting

OBJECTIVE

Retrospective comparisons of selected patients undergoing off-pump versus conventional on-pump coronary artery bypass grafting have yielded inconsistent results and raised concerns about completeness of revascularization in off-pump coronary artery bypass grafting.

METHODS

Two hundred unselected patients referred for elective primary coronary artery bypass grafting were randomly assigned to undergo off-pump coronary artery bypass grafting with an Octopus tissue stabilizer (Medtronic, Inc, Minneapolis, Minn) or conventional coronary artery bypass grafting with cardiopulmonary bypass by a single surgeon. Revascularization intent determined before random assignment was compared with the revascularization performed. All management followed strict, unbiased, criteria-driven protocols. Patients and nonoperative care providers were blinded to surgical group.

RESULTS

Baseline characteristics were similar. The number of grafts performed per patient (mean +/- SD 3.39 +/- 1.04 for off-pump coronary artery bypass grafting, 3.40 +/- 1.08 for conventional coronary artery bypass grafting) and the index of completeness of revascularization (number of grafts performed/number of grafts intended, 1.00 +/- 0.18 for off-pump coronary artery bypass grafting, 1.01 +/- 0.09 for conventional coronary artery bypass grafting) were similar. Likewise, the index of completeness of revascularization was similar between groups for the lateral wall. Combined hospital and 30-day mortalities and stroke rates were similar. Postoperative myocardial serum enzyme measures were significantly lower after off-pump coronary artery bypass grafting, suggesting less myocardial injury. Adjusted postoperative thromboelastogram indices, fibrinogen, international normalized ratio, and platelet levels all showed significantly less coagulopathy after off-pump coronary artery bypass grafting. Patients undergoing off-pump coronary artery bypass grafting received fewer units of blood, were more likely to avoid transfusion altogether, and had a higher hematocrit at discharge. Cardiopulmonary bypass was an independent predictor of transfusion (odds ratio 2.42, P =.0073) by multivariate analysis. More patients undergoing off-pump coronary artery bypass grafting were extubated in the operating room and within 4 hours. Postoperative length of stay (in days) was shorter for off-pump coronary artery bypass grafting (5.1 +/- 6.5 for off-pump coronary artery bypass grafting, 6.1 +/- 8.2 for conventional coronary artery bypass grafting, P =.005 by Wilcoxon test). One patient (in the conventional coronary artery bypass grafting group) required angioplasty for graft closure within 30 days.

CONCLUSIONS

When compared with conventional coronary artery bypass grafting with cardiopulmonary bypass, off-pump coronary artery bypass grafting achieved similar completeness of revascularization, similar in-hospital and 30-day outcomes, shorter length of stay, reduced transfusion requirement, and less myocardial injury.

Maintaining hemodynamic stability and myocardial performance during off-pump coronary bypass surgery

Patients presenting for coronary artery bypass (CAB) surgery are now older and have more comorbid conditions. Off-pump (OPCAB) methods may reduce morbidity and mortality in these higher risk patients. Multivessel surgery has been limited by the difficulty in maintaining hemodynamic stability during lateral wall vessel grafting. Techniques for providing safe access to lateral wall vessels were applied in a largely unselected group of 665 OPCAB patients with emphasis on the avoidance of right ventricular compression. Safe access to essentially all target coronary arteries was achieved with very little need for pharmacological or mechanical support. No patient required new intraaortic balloon pumping and no patient required urgent conversion to cardiopulmonary bypass. Access to essentially all target coronary arteries can be achieved and myocardial performance can be maintained when strict attention is paid to operative strategies designed to minimize right-side heart compression.

A comparison of on-pump and off-pump coronary bypass surgery in low-risk patients

BACKGROUND

The performance of coronary bypass surgery without cardiopulmonary bypass ("off pump") may reduce perioperative morbidity and costs, but it is uncertain whether the outcome is similar to that involving the use of cardiopulmonary bypass ("on pump").

METHODS

In a multicenter, randomized trial, we randomly assigned 139 patients with predominantly single- or double-vessel coronary disease to on-pump surgery and 142 to off-pump surgery. Cardiac outcome and cost effectiveness were determined one year after surgery. The uncertainty surrounding the cost-effectiveness ratio (cost differences per quality-adjusted year of life gained) was addressed by bootstrapping.

RESULTS

At one year, the rate of freedom from death, stroke, myocardial infarction, and coronary reintervention was 90.6 percent after on-pump surgery and 88.0 percent after off-pump surgery (absolute difference, 2.6 percent; 95 percent confidence interval, - 4.6 to 9.8). Graft patency in a randomized subgroup of patients was 93 percent after on-pump surgery and 91 percent after off-pump surgery (absolute difference, 2.0 percent; 95 percent confidence interval, - 6.5 to 10.4). On-pump surgery was associated with $1,839 in additional direct costs per patient ($14,908 vs. $13,069--a difference of 14.1 percent) and an increase in quality-adjusted years of life of 0.83 as compared with 0.82 (difference, 0.01 year; 95 percent confidence interval, - 0.03 to 0.04). Off-pump surgery was more cost effective than on-pump surgery in 95 percent of bootstrap estimates.

CONCLUSIONS

In low-risk patients, there was no difference in cardiac outcome at one year between those who underwent on-pump bypass surgery and those who underwent off-pump surgery. Off-pump surgery was more cost effective.