Coronary artery bypass without cardiopulmonary bypass: analysis of short-term and mid-term outcome in 220 patients

The top 100 manuscripts in emergency cardiac surgery. Potential role in cardiothoracic training. A bibliometric analysis

Background

Emergency Cardiac Surgery (ECS) is a component of cardiothoracic training. Citations are considered to represent a papers influence. Bibliometric analyses allow us to identify the most influential work, and future research. We aim to highlight the key research themes within ECS and determine their potential impact on cardiothoracic training.

Methods

Thomas Reuters Web of Science was searched using terms [Emergency AND Card* AND Surg*]. Results were ranked by citation and reviewed by a panel of cardiac surgeons to identify the top 100 cited papers relevant to ECS. Papers were analysed by topic, journal and impact. Regression analysis was used to determine a link between impact factor and scientific impact.

Results

3823 papers were identified. Median citations for the top 100 was 88. The paper with the highest impact was by Nashef et al. focusing on the use of EuroSCORE (2043 citations). The Annals of Thoracic Surgery published most papers (n = 18:1778 citations). The European Journal of Cardiothoracic Surgery coveted the most citations (n = 2649). The USA published most papers (n = 55).The most ubiquitous topics were; risk stratification, circulatory support and aortic surgery. A positive relationship between journal impact fact and the scientific impact of manuscripts in ECS (P = 0.043) was deduced.

Conclusion

This study is the first of its kind and identified the papers which are likely to the contribute most to training and understanding of ECS. A papers influence is partially determined by journal impact factor. Bibliometric analysis is a potent tool to identify surgical training needs.

Off-pump grafting does not reduce postoperative pulmonary dysfunction

Objectives Pulmonary dysfunction is a recognized postoperative complication that may be linked to use of cardiopulmonary bypass. The off-pump technique of coronary artery bypass aims to avoid some of the complications that may be related to cardiopulmonary bypass. In this study, we compared the influence of on-pump or off-pump coronary artery bypass on pulmonary gas exchange following routine surgery. Methods Fifty patients (mean age 60.4 ± 8.4 years) with no preexisting lung disease and good left ventricular function undergoing primary coronary artery bypass grafting were prospectively randomized to undergo surgery with or without cardiopulmonary bypass. Alveolar/arterial oxygen pressure gradients were calculated prior to induction of anesthesia while the patients were breathing room air, and repeated postoperatively during mechanical ventilation and after extubation while inspiring 3 specific fractions of oxygen. Results Baseline preoperative arterial blood gases and alveolar/arterial oxygen pressure gradients were similar in both groups. At both postoperative stages, the partial pressure of arterial oxygen and alveolar/arterial oxygen pressure gradients increased with increasing fraction of inspired oxygen, but there were no statistically significant differences between patients who underwent surgery with or without cardiopulmonary bypass, either during ventilation or after extubation. Conclusions Off-pump surgery is not associated with superior pulmonary gas exchange in the early postoperative period following routine coronary artery bypass grafting in patients with good left ventricular function and no preexisting lung disease.

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.

Minimally invasive direct coronary artery bypass surgery with right gastroepiploic artery for redo patients

Coronary artery bypass grafting (CABG) has been widely performed for coronary artery disease. Therefore, cases requiring reoperative CABG are increasing. We performed a minimally invasive direct coronary artery bypass (MIDCAB) procedure on four patients, as reoperative CABG surgery for the right coronary artery (RCA), employing the right gastroepiploic artery (RGEA). The target sites were the distal RCA in two patients and the posterior descending (PD) branch in the other two. Complete revascularization was accomplished in all patients without sternotomy, cardiopulmonary bypass (CPB), or blood transfusion. The mean operative time was 3.0 h (range: 2.4-3.7 h). Postoperative coronary angiography showed all grafts to be patent. All patients were discharged without postoperative complications and remained free from cardiac events during a mean follow-up period of 1.5 years (range: 0.5-3.0 years). MIDCAB for the RCA, employing the RGEA via a subxiphoid incision showed, excellent revascularization in redo CABG cases. This technique is a safe and effective method for redo cases.

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.

Vettath's anastamotic obturator--our experience of 269 proximal anastomoses

BACKGROUND

Coronary artery bypass grafting (CABG) has come full circle-it started as an off-pump affair, then became an on pump one and now we are trying to keep off the pump again. One of the main reasons for this has been the neurological sequelae subsequent to CABG. But neurological problems kept causing concern even in off-pump CABGs (OPCAB). Side clamping the aorta was thought to be the major factor and thus came the concept of 'no touch proximal anastomoses' onto the aorta (1). Though a variety of proximal anastamotic devices are available in the market, high cost is a matter of real concern in third world countries like India. Hence, this endeavor of ours to fabricate an anastamotic device of our own-'the Vettath's anastamotic obturator' (VAO) for proximal anastomoses of saphenous vein grafts (SVG) onto the aorta. VAO is a stainless steel rod with three grooves and a guard at the end, which sinks into the aorta, through a punch hole, cordoned off by two wide purse string sutures.

METHODS

After trials on perfused animal heart models, we started using this device on humans. We have performed 269 proximal anastomoses using the VAO in 177 of our OPCAB patients in the past 1 year (till July 2003). Ninety-five of them had single top ends, 72 had 2 top ends and 10 had 3 top ends onto the aorta. We have used this on disease free islands on four patients with palpable aortic plaques. Initially all anastomoses were of the proximal first type (to ensure that the flow was adequate). Now-a-days, with confidence, distal first anastomoses are being performed.

RESULTS

We had no operative mortality in this group. None of our patients needed IABP support. One patient reported back with angina, after 3 months-he was studied and his grafts were found to be patent. All patients, except three, are being followed up till date and they are leading active symptom free and event free lives.

DISCUSSION

It is logical to think that avoidance of side clamp on the aorta reduces the risk of neurologic complications. Vettath's anastamotic obturator is an indigenous, cheap and reusable alternative to the other costlier devices, which serve the same purpose. Though there is a small learning curve, results are gratifying and complications are few.

Effects on Lung Function in Patients Undergoing Coronary Artery Surgery on versus off Cardiopulmonary Bypass: A Randomized Trial

Background

Coronary revascularization is associated with respiratory dysfunction and poor gas exchange postoperatively. Cardiopulmonary bypass (CPB) has been implicated as a possible explanation for this phenomenon. This study investigated respiratory function in patients undergoing coronary artery bypass grafting (CABG) on-CPB versus off-CPB to determine whether the off-CPB condition results in improved postoperative pulmonary function.

Methods

Forty patients were randomized into 1 of 2 groups: CABG on-CPB (group A) or off-CPB (group B). Pulmonary function tests, including spirometry and diffusion studies, were performed preoperatively and on postoperative day 5. Arterial blood gases on 100% oxygen were taken preoperatively (TP1), 15 minutes after sternal closure (TP2), and 3 hours postoperatively (TP3).

Results

The arterial partial pressure of oxygen (PaO2) on FiO2 1.0 decreased from 59.5 ± 11.5 kPa and 55.7 ± 12.2 kPaat TP1 to 39.5 ± 16 kPa and 39.7 ± 13 kPa at TP2 in groups A and B, respectively (P < 0.001), with no significant difference between groups. At TP3, the PaO2 partially recovered toward preoperative levels (P < 0.05). Spirometry revealed a significant reduction in FEV1 and FVC on the fifth postoperative day (P < 0.001), with no significant difference between groups. The corrected transfer factor for carbon monoxide reduced significantly in group A from 7.9 ± 2.5 mmolmin–1 · kPa–1 preoperatively to 5.1 ± 1.6 mmolmin–1 · kPa–1 postoperatively (P < 0.05). This reduction was not seen in group B.

Conclusions

Coronary artery surgery is associated with a marked reduction in lung function as measured by pulmonary function tests and PaO2. Diffusion studies revealed that on-CPB patients had significantly reduced diffusion capacities postoperatively compared with patients in the off-CPB group.

CARDIOMED CORONARY FLOW METER FOR PREVENTION OF EARLY OCCLUSION IN AORTOCORONARY BYPASS GRAFTING

INTRODUCTION

The number of patients undergoing technically demanding off-pump myocardial revascularization is increasing, these days. Some researchers question the quality of the aortocoronary bypasses done on the beating heart and consequently their good patency.

MATERIAL AND METHODS

50 consecutive patients underwent off pump coronary surgery using sequential bypass technique, at our department. The quality of constructed grafts was evaluated using the CardioMed Trace System (CM4008, Medi-Stim As, Oslo, Norway) (TTFM).

RESULTS

All sequential bypasses showed good per-operative quality with a mean fl ow of 69.4 ml/min.

CONCLUSION

TTFM seems to be an effective tool for the per-operative aortocoronary bypass patency verification and should help to prevent early graft occlusion.

ABBREVIATIONS

TTFM transit time flow meter.

Trainees operating on high-risk patients without cardiopulmonary bypass: a high-risk strategy?

BACKGROUND

The safety of teaching off-pump coronary artery bypass grafting to trainees is best tested in high-risk patients, who are more likely to experience significant morbidity after surgery. This study compared outcomes of off-pump coronary artery bypass grafting operations performed by consultants and trainees in high-risk patients.

METHODS

Data for consecutive patients undergoing off-pump coronary artery bypass grafting were collected prospectively. Patients satisfying at least one of the following criteria were classified as high-risk: age older than 75 years, ejection fraction less than 0.30, myocardial infarction in the previous month, current congestive heart failure, previous cerebrovascular accident, creatinine greater than 150 micromol/L, respiratory impairment, peripheral vascular disease, previous cardiac surgery, and left main stem stenosis greater than 50%. Early morbidity, 30-day mortality, and late survival were compared.

RESULTS

From April 1996 to December 2002, 686 high-risk patients underwent off-pump coronary artery bypass grafting revascularization. Operations by five consultants (416; 61%) and four trainees (239; 35%) were the focus of subsequent analyses. Nine visiting or research fellows performed the other 31 operations. Prognostic factors were more favorable in trainee-led operations. On average, consultants and trainees grafted the same number of vessels. There were 18 (4.3%) and 5 (1.9%) deaths within 30 days, and 14 (3.4%) and 5 (1.9%) myocardial infarctions in consultant and trainee groups, respectively. After adjusting for imbalances in prognostic factors, odd ratios for almost all adverse outcomes implied no increased risk with trainee operators, although patients operated on by trainees had longer postoperative stays and were more likely to have a red blood cell transfusion. Kaplan-Meier cumulative mortality estimates at 24-month follow-up were 10.5% (95% confidence interval, 7.7% to 14.2%) and 6.4% (95% confidence interval, 3.8% to 10.9%) in consultant and trainee groups, respectively (hazard ratio = 0.60 [95% confidence interval, 0.37 to 0.99]; p = 0.05).

CONCLUSIONS

Off-pump coronary artery bypass grafting surgery in high-risk patients can be safely performed by trainees.

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.

Anaesthesia for coronary artery bypass: should it differ off-pump and on-pump?

The advent of suction myocardial stabilizers has caused a resurgence in offpump coronary artery bypass (OPCAB). It may avoid end-organ injury associated with cardiopulmonary bypass, e.g. stroke, neuropsychological and renal dysfunction. Both low- and high-risk patients have improved outcomes with OPCAB (Moshkovitz et al, 1995; Nierich et al, 1999; Arom et al, 2000).

Off-pump multivessel revascularization: efficacy of suction type of coronary stabilizer

OBJECTIVE

Off-pump coronary artery bypass grafting (CABG) has come into widespread use with the availability adequate coronary stabilization devices. We studied the efficacy of second-generation coronary stabilization devices (suction device) comparing to the first-generation device (compression device).

METHODS

We prospectively analyzed consecutive patients who underwent isolated off-pump CABG via a midline sternotomy at Shin-Tokyo Hospital Group between July 1, 1996, and August 31, 2000, comparing perioperative, and follow-up data in the group using a suction device (group S) to that in the group using a compression device (group C).

RESULTS

Preoperative risk factors were identical between the two groups, with the exception of a higher incidence of three vessel disease in group S. Complete revascularization increased from 47.3% in group C to 88.1% in group S, and the number of distal anastomoses from 2.1 +/- 0.6 in group C to 2.9 +/- 0.9 in group S. Revascularization of the circumflex artery was achieved in 21.7% of group S patients, which was significantly higher than that in group C (2.2%). Postoperative recovery, mortality, and morbidity did not differ significantly between groups. Calculated event-free rates at 2 years was 88.7% in group C and 92.0% in group S (p = NS).

CONCLUSIONS

Anastomosis to the posterior wall of the heart using the suction device is safe. An increased number of distal anastomoses may reduce the occurrence of cardiac events related to incomplete revascularization.

Daily comparison of respiratory functions between on-pump and off-pump patients undergoing CABG

OBJECTIVE

Widespread application of on-pump revascularization procedures is increasing due to the thought of elimination of untoward effects of cardiopulmonary circuit. Thus, whether off-pump coronary artery surgery eliminates side effects especially related to respiratory functions is still controversial. Although many previous studies have evaluated these respiratory functions, daily comparison of 12 parameters was not included in any of the studies. The aim of our prospective study was to ascertain whether off-pump coronary operation improves pulmonary functions and postoperative recovery period when compared with on-pump technique and whether early discharge of patients with off-pump surgery is the result of respiratory improvement.

METHODS

Eighteen patients in each group were included: on-pump group underwent coronary revascularization with cardiopulmonary bypass and off-pump with stabilization. Respiratory function tests and arterial blood gas analyses were performed preoperatively and daily after operation function tests included forced expiratory volume (FEV) in 1s, forced vital capacity (FVC), expiratory reserve volume, vital capacity, quotient of FEV in 1s to FVC, maximal voluntary ventilation (MVV), tidal volume, and forced midexpiratory flow. Blood gas analyses included partial arterial oxygen and carbon dioxide pressure, arterial pH and hematocrit (Hct).

RESULTS

Preoperative pulmonary functions and arterial blood gases were not statistically significant between groups except MVV and partial arterial oxygen pressure. MVV was slightly higher in on-pump group and partial arterial oxygen pressure was slightly lower in on-pump group. During postoperative first day Hct (P=0.004) and FEV in 1s (P=0.049) values and third day partial arterial oxygen pressure (P=0.011) and Hct (P=0.011) values were lower in on-pump group. Mean extubation, duration in postoperative suit and hospital discharge times, mean blood loss were not statistically significant between groups postoperatively.

CONCLUSION

Pulmonary functions and arterial blood gases were not improved in off-pump patients when compared with on-pump patients. Patients going to be surgically revascularized should not be altered to off-pump surgery merely with the hope of improving respiratory functions with off-pump technique. As the postoperative stay times at surgical theatre and hospital is not different and the extubation times were similar, early discharge of patients with off-pump surgery cannot be related merely to better preservation of respiratory functions.

Experimental coronary artery occlusion: relevance to off-pump cardiac surgery

Mechanical coronary artery occlusion is required for minimally invasive direct coronary artery bypass and off-pump coronary artery bypass surgery. It is important that the method of occlusion be minimally traumatic. Chronic effects of these methods have never been studied. Temporary occlusion of coronaries utilizing suture snare, silastic loop snare, and bulldog clamp was carried out in 12 Yucatan pigs. Three animals each were sacrificed acutely and at 3, 6, and 12 months. The area of occlusion of each vessel was examined by light microscopy and the degree of damage recorded. In the animals sacrificed acutely, there was more damage using the suture snare than with the other 2 methods, but there was minimal damage at longer intervals. There was slight damage acutely and chronically with the bulldog technique. No damage was seen acutely with the silastic loop technique, but some late damage was found. The techniques of coronary artery dissection and occlusion used for minimally invasive and off-pump bypass surgery may contribute to early postoperative graft occlusion.

Urgent off-pump coronary artery bypass grafting

OBJECTIVES

The use of off-pump coronary artery bypass grafting (CABG) has become widespread, since it has proven less invasive and to promote early recovery. In this study, we investigated the efficacy of off-pump CABG in patients in the evolving phase of acute myocardial infarction.

METHODS

Retrospective chart review was carried out for patients undergoing urgent isolated off-pump and on-pump CABG at Shin-Tokyo Hospital Group between January 1991 and June 2001. The patients' demographic, operative data, and postoperative results were collected.

RESULTS

The off-pump group consisted of 19 males and 11 females with a mean age of 72.0 years and the on-pump group of 91 males and 38 females with a mean age of 64.3 years. Preoperative use of intraaortic balloon pumping and preoperative shock was more frequently observed in the on-pump group. The mean number of distal anastomoses was 3.1 +/- 0.9 in the off-pump group and 3.2 +/- 1.1 in the on-pump group (p = NS). Intubation time (18.5 vs 32.9 hours), ICU stay (3.4 vs 4.9 days), and postoperative stay (13.5 vs 24.3 days) were significantly shorter in the off-pump group than in the on-pump group (P < 0.05). The frequency of the major complications was significantly lower in the off-pump group (9/30, 30%) than the on-pump group (65/129, 50.4%), especially for postoperative low output syndrome (p < 0.05). Multivariate analysis demonstrated a significant reduction in the recovery period by use of off-pump CABG. Early follow-up results were similar between the two groups, in terms of late cardiac events and survival.

CONCLUSION

Urgent off-pump CABG is safe and provides early recovery, provided that the patient's intraoperative hemodynamics are taken into account.

Evaluation of the effectiveness of off-pump coronary artery bypass grafting in high-risk patients: an observational study

BACKGROUND

Coronary artery bypass grafting in high-risk patients carries substantial morbidity. We compared the effectiveness of off-pump revascularization with that of conventional coronary artery bypass grafting using cardiopulmonary bypass and cardioplegic arrest in consecutive high-risk patients.

METHODS

From April 1996 to December 2000, clinical data for consecutive patients undergoing coronary artery revascularization were prospectively entered into a database. Data were extracted for all patients considered to be high risk, defined as the presence of one or more of ten adverse prognostic factors. Hospital mortality and early morbidity were compared between two groups of patients, the on-pump and off-pump groups.

RESULTS

The study group comprised 1,570 consecutive high-risk patients, 332 (21.1%) of whom underwent an off-pump operation. Patients in the on-pump group had fewer high-risk factors and lower Parsonnet scores and were less likely to be 75 years of age or older, to have peripheral vascular disease or hypercholesterolemia, or to have sustained a previous transient ischemic attack. However, they were more likely to be assigned to a higher Canadian Cardiovascular Society class and had more extensive coronary artery disease and were more likely to have unstable angina, to require urgent or emergency operations, and to receive more grafts than those undergoing off-pump procedures. Unadjusted odds ratios for intensive care unit or high-dependency unit stay, total length of stay, blood loss of more than 1,000 mL, postoperative hemoglobin and transfusion requirement all showed a highly significant benefit for the off-pump group (p < or = 0.005; odds ratios, 0.33 to 0.65). After adjustment for prognostic variables, odds ratios remained essentially unaltered (adjusted odds ratio estimates 0.36 to p < 0.05) except for blood loss of more than 1,000 mL (adjusted odds ratio estimate, 0.82; p = 0.22). Sensitivity analyses confirmed the robustness of these findings.

CONCLUSIONS

Off-pump coronary artery bypass grafting is safe, effective, and associated with reduced morbidity in high-risk patients compared with conventional coronary artery revascularization.

Intraoperative evaluation of coronary anastomosis by transit-time ultrasonic flow measurement

BACKGROUND

Intraoperative assessment of the anastomosis is important during coronary bypass on a beating heart. The purpose of this study is to predict the quality of anastomosis using transit-time flow measurement and to find out the most accurate indicator.

METHODS

Eight swine underwent internal thoracic-anterior descending coronary artery bypass grafting on a beating heart. Flow measurement and angiography were performed at various degrees of stenosis created on the graft. As flow parameters, total flow, systolic flow, diastolic flow, diastolic/total flow ratio, systolic peak flow, diastolic peak flow, systolic/diastolic peak flow index, and pulsatility index were used. Mixed procedure and probability test (negative means successful anastomosis) were used to analyze the diagnostic ability.

RESULTS

Diastolic flow, diastolic/total flow ratio, diastolic peak flow, systolic/diastolic peak flow index, and pulsatility index showed significant variance with increased stenosis. Among these measures, diastolic/total flow ratio showed the highest value of area under the curve (0.91) and the highest specificity (82%) at 90% sensitivity with actual value of 42%.

CONCLUSIONS

Diastolic/total flow ratio was the most reliable indicator to predict critical stenosis in coronary artery bypass grafting.

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.

Early outcome after off-pump versus on-pump coronary bypass surgery: results from a randomized study

BACKGROUND

The use of cardiopulmonary bypass during coronary artery bypass surgery (CABG) has been associated with substantial morbidity. The recent introduction of cardiac stabilizers facilitates CABG without cardiopulmonary bypass (off-pump CABG), but it is unknown whether cardiac outcome after off-pump surgery is similar to that for the on-pump procedure.

METHODS AND RESULTS

In a multicenter trial, 281 patients (mean age 61 years, SD 9 years) were randomly assigned to off-pump or on-pump CABG. In-hospital results and cardiac outcome and quality of life after 1 month are presented. Cardiac outcome was defined as survival free of stroke, myocardial infarction, and coronary reintervention. The mean numbers of distal anastomoses per patient were 2.4 (SD 1.0) and 2.6 (SD 1.1) in the off-pump and on-pump groups, respectively. Completeness of revascularization was similar in both groups. Blood products were needed during 3% of the off-pump procedures and 13% of the on-pump procedures (P<0.01). Release of creatine kinase muscle-brain isoenzyme was 41% less in the off-pump group (P<0.01). Otherwise, no differences in complications were found postoperatively. Off-pump patients were discharged 1 day earlier. At 1 month, operative mortality was zero in both groups, and quality of life had improved similarly. In both groups, 4% of the patients had recurrent angina. The proportions of patients surviving free of cardiovascular events were 93.0% in the off-pump group and 94.2% in the on-pump group (P=0.66).

CONCLUSIONS

In selected patients, off-pump CABG is safe and yields a short-term cardiac outcome comparable to that of on-pump CABG.

Comparison of coronary-artery bypass surgery and stenting for the treatment of multivessel disease

BACKGROUND

The recent recognition that coronary-artery stenting has improved the short- and long-term outcomes of patients treated with angioplasty has made it necessary to reevaluate the relative benefits of bypass surgery and percutaneous interventions in patients with multivessel disease.

METHODS

A total of 1205 patients were randomly assigned to undergo stent implantation or bypass surgery when a cardiac surgeon and an interventional cardiologist agreed that the same extent of revascularization could be achieved by either technique. The primary clinical end point was freedom from major adverse cardiac and cerebrovascular events at one year. The costs of hospital resources used were also determined.

RESULTS

At one year, there was no significant difference between the two groups in terms of the rates of death, stroke, or myocardial infarction. Among patients who survived without a stroke or a myocardial infarction, 16.8 percent of those in the stenting group underwent a second revascularization, as compared with 3.5 percent of those in the surgery group. The rate of event-free survival at one year was 73.8 percent among the patients who received stents and 87.8 percent among those who underwent bypass surgery (P<0.001 by the log-rank test). The costs for the initial procedure were $4,212 less for patients assigned to stenting than for those assigned to bypass surgery, but this difference was reduced during follow-up because of the increased need for repeated revascularization; after one year, the net difference in favor of stenting was estimated to be $2,973 per patient.

CONCLUSION

As measured one year after the procedure, coronary stenting for multivessel disease is less expensive than bypass surgery and offers the same degree of protection against death, stroke, and myocardial infarction. However, stenting is associated with a greater need for repeated revascularization.

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.

Off-pump coronary artery bypass. Mid-term results

OBJECTIVES

Off-pump coronary artery bypass grafting (CABG) on the beating heart has become popular procedure in cardiac surgery and its initial results appeared favorable. We report our early and mid-term results of off-pump CABG performed at Shin-Tokyo Hospital.

METHODS

Medical records of patients undergoing off-pump or conventional on-pump CABG from September 1, 1996, to August 31, 1999 were retrospectively reviewed. Patients underwent off-pump CABG were further classified into 2 groups; MIDCAB (Off-pump CABG for single vessel revascularization via a small skin incision) and OPCAB (off-pump CABG mainly approached via midline sternotomy) group. Their preoperative, perioperative, and follow-up data were collected and analyzed.

RESULTS

Among a total of 995 cases of CABG, 194 cases were off-pump CABG (male/female 142/52, mean age 66.9). The mean number of distal anastomoses in off-pump CABG was 1.9 +/- 0.9 (1.0 +/- 0.0 in MIDCAB and 2.3 +/- 0.7 in OPCAB), which was significantly fewer than in on-pump CABG (3.6 +/- 1.1), with p < 0.0001. Intubation time (5.3 +/- 5.7 hours in off-pump CABG vs 13.1 +/- 24.2 hours in on-pump CABG), ICU stay (1.7 +/- 1.1 vs 3.2 +/- 3.0 days), and postoperative hospital stay (14.0 +/- 7.9 vs 18.1 +/- 12.1 days) in off-pump CABG were significantly shorter than in on-pump CABG (p < 0.0001). In the off-pump CABG group, there were no in-hospital deaths and 14 major complications, fewer than in on-pump CABG (8 hospital deaths and 114 major complications). Postoperative angiography before hospital discharge was conducted in 80 patients (41.2%) and showed 2 occlusions, giving a graft patency rate of 98.6% in the off-pump group. During follow-up (0.9 +/- 0.6 year) period, there were 5 non-cardiac deaths and 20 cardiac events in the off-pump group. The actuarial survival rate at 36 months was 94.6% for off-pump CABG, showing no significant difference from the rate for conventional CABG patients (95.2% at 36 month, p = NS) The event-free rate was 84.0% at 36 months in off-pump CABG patients; however, which was less favorable than on-pump CABG patients (88.0% at 36 months, p < 0.05).

CONCLUSIONS

Both in-hospital and mid-term results for off-pump CABG patients were acceptable. Isolated CABG can thus be safely performed without cardiopulmonary bypass. Advances in coronary stabilization have contributed to these improved results. The observed long-term cardiac events may be related to incomplete revascularization.

Revascularization of severe hibernating myocardium in the beating heart: early hemodynamic and metabolic features

BACKGROUND

We investigated the effects of coronary artery bypass grafting (CABG) without cardiopulmonary bypass (CPB) in selected patients with severe hibernating myocardium.

METHODS

Twelve patients (EF = 25% +/- 0.7%) with reversible ventricular dysfunction (from 2.0 +/- 0.06 to 1.6 +/- 0.05 left ventricular score index by echodobutamine, p < 0.01) in the territory of the left anterior descending artery (LAD) have been studied. Revascularization was achieved by anastomosing the left internal mammary artery to the LAD. The ischemic time of LAD was 9.0 +/- 0.4 minutes.

RESULTS

Left ventricular function increased 6 hours and 48 hours after revascularization (left ventricular stroke work index from 32 +/- 1.8 to 42 +/- 1.5 and 40 +/- 0.6 gxm/m2, respectively: p = 0.0001). During the surgical procedure, the heart did not release lactate or creatine phosphokinase. There were no perioperative deaths or severe complications.

CONCLUSIONS

Early hemodynamic and metabolic features of CABG without CPB in patients with hibernating myocardium suggest that this procedure is safe and results in a significant improvement of cardiac function without affecting myocardial metabolism.

The Octopus Study: rationale and design of two randomized trials on medical effectiveness, safety, and cost-effectiveness of bypass surgery on the beating heart

The Octopus Study consists of two multicenter randomized clinical trials in which coronary artery bypass grafting on the beating heart (off-pump CABG) using the Utrecht Octopus Method is compared to intracoronary stent implantation and conventional CABG. The primary endpoint in the comparison of off-pump CABG versus stent implantation (OctoStent Trial) is medical effectiveness (i.e., absence of reintervention and major adverse cardiac and cerebrovascular events at 1 year after treatment). The primary endpoint in the comparison of off-pump CABG versus conventional CABG (OctoPump Trial) is cerebral safety (i.e., absence of cognitive deficits and cerebrovascular events at 3 months after treatment). Secondary endpoints in both trials include presence and severity of angina, quality of life, exercise capacity, and cost-effectiveness. A total of 560 patients will be enrolled. A random sample of 210 patients will undergo repeat angiography at 1 year to assess angiographic restenosis rate and graft patency. Including 1-year follow-up, the study will last for 3 years. Control Clin Trials 2000;21:595-609

Coronary Artery Bypass Grafting without Cardiopulmonary Bypass

Between March 1994 and April 1998, 2869 patients underwent coronary artery bypass grafting at our institution. Of these, 415 (14.5%) with a mean age of 54.4 ± 9.9 years were operated on without cardiopulmonary bypass. Internal thoracic artery was used in 402 cases (97%) and the left anterior descending artery was revascularized in all except 1. Distal anastomoses ranged from 1 to 3, with a mean of 1.45 ± 0.58. Major postoperative complications comprised reoperation because of internal thoracic artery spasm in 1 patient, lower extremity ischemia due to intraaortic balloon pumping in 1 patient, revision for excessive bleeding in 3, and perioperative myocardial infarction in another 3. Hospital mortality was 1.2% (5 deaths). Coronary angiography was performed in 38 patients, 1 to 44 months postoperatively. Examination of 56 distal anastomoses revealed a patency rate of 86.1% for internal thoracic artery grafts and 55% for saphenous vein grafts. It was concluded that coronary bypass surgery without cardiopulmonary bypass gave favorable results in the early postoperative period. However, considering the late graft patency rates, either patient selection or the technique should be reevaluated.

Pulmonary abnormalities after coronary arterial bypass grafting operation: cardiopulmonary bypass versus mechanical stabilization

BACKGROUND

Cardiopulmonary bypass has been implicated in causing poor pulmonary gas exchange postoperatively in patients undergoing coronary artery bypass grafting procedures. This randomized prospective study was conducted to determine whether patients undergoing coronary artery bypass grafting operations using cardiac stabilization and thereby avoiding cardiopulmonary bypass will have improved pulmonary function postoperatively.

METHODS

Fifty-eight patients were randomized to one of two groups: coronary artery bypass grafting operation with stabilization or coronary artery bypass grafting operation with cardiopulmonary bypass. Preoperative and postoperative pulmonary gas exchange measurements were performed on intubated patients, including the arterial partial pressure of oxygen on 100% inspired oxygen, the alveolar-arterial oxygen gradient, and pulmonary shunt. Static and dynamic lung compliance measurements were performed postoperatively. Hemodynamic variables (including creatine kinase-MB and troponin levels), intubation time, postoperative bleeding, and blood transfusions were compared.

RESULTS

Both study groups had a large decrease in arterial partial pressure of oxygen on 100% inspired oxygen (p < 0.0001) and a significant postoperative increase in the alveolar-arterial oxygen gradient (p < 0.0001). There was no statistical difference in the postoperative gas exchange between the two groups; however, the postoperative pulmonary shunt was significantly better in the stabilization group (24% versus 31%, p = 0.03). The patients were extubated in the intensive care unit earlier in the stabilization group (8.2 hours versus 9.2 hours, not significant). The mean static and dynamic lung compliance postoperatively was lower in the stabilization group, although not statistically significant (p = 0.06).

CONCLUSIONS

Coronary artery bypass grafting operation using cardiac stabilization technique is safe and avoids the risk of cardiopulmonary bypass. The pulmonary gas exchange postoperatively is comparable to standard cardiopulmonary bypass procedures, but a reduced postoperative pulmonary shunt was seen in the stabilization group.

Minimally invasive coronary artery bypass surgery

Advances in videoscopic instrumentation and expanding experience with the performance of coronary artery bypass surgery without cardiopulmonary circulatory support is changing the surgical approach to many patients requiring coronary arterial revascularization. We describe the present status of minimally invasive coronary artery bypass surgery being used today.

Surgical myocardial revascularization without cardiopulmonary bypass

BACKGROUND

Though coronary artery bypass grafting (CABG) without cardiopulmonary bypass is being performed with increasing frequency, in the absence of adequate angiographic follow-up, safety, reproducibility, and efficacy of the procedure remain doubtful. In this prospective study, we report the results obtained by 100% angiographic follow-up of 96 consecutive patients.

METHODS

A total of 96 patients (age range 33 to 76 years) underwent CABG without cardiopulmonary bypass. Single vessel disease was present in 46 (47.9%) patients, double vessel disease in 31 (32.3%), and triple vessel disease in 19 (19.8%) patients. All patients were operated through a standard midsternotomy and an optimal combination of pharmacological and mechanical methods were used to restrict cardiac movements during anastomosis. All patients underwent coronary angiography before discharge from the hospital.

RESULTS

A total of 160 grafts were placed (range 1 to 4 grafts per patient, average 1.7+/-0.3 grafts per patient). A single graft was placed in 46 patients, double grafts in 38, triple grafts in 10, and quadruple grafts in 2 patients. Various grafts included pedicled left internal mammary artery (LIMA) (n = 95), free LIMA (n = 1), right internal mammary artery (n = 14), radial artery (n = 24), right gastroepiploic artery (n = 5), and saphenous vein grafts (n = 21). Operative mortality was 1.0% (1 of 96). Two patients required reoperation for excessive bleeding. Mean hospital stay was 5.7+/-1.2 days. Overall angiographic patency was 95.0% with LIMA patency of 97.9% (93 of 95). One patient with block in midsegment of LIMA was reoperated using cardiopulmonary bypass. Follow-up ranged from 4 to 17 months (mean 8.2+/-3.1 months). Two patients (one with narrowed LIMA to left anterior descending artery anastomosis, and one with patent anastomosis) had residual angina.

CONCLUSIONS

Coronary artery bypass grafting without cardiopulmonary bypass is a reproducible, effective, and safe option in selected group of patients. A conscientious approach in patient selection and route of operation is required.

Systematic off-pump coronary artery revascularization in multivessel disease: experience of three hundred cases

OBJECTIVE

We sought to report our recent experience with off-pump coronary artery revascularization in multivessel disease.

METHODS

Between October 1996 and December 1998, 300 off-pump beating heart operations were performed at the Montreal Heart Institute by a single surgeon, representing 94% of all procedures undertaken during this same time frame (97% for 1998). This cohort of patients was compared with 1870 patients operated on with cardiopulmonary bypass from 1995 to 1996.

RESULTS

Mean age, sex distribution, and preoperative risk factors were comparable for the two groups. On average, 2.92 +/- 0.8 and 2.84 +/- 0.6 grafts per patient were completed in the beating heart and cardiopulmonary bypass groups, respectively. A majority of patients (70%) had either a triple or quadruple bypass. Coronary anastomoses were achieved with myocardial mechanical stabilization and heart "verticalization." Ischemic time was shorter in the beating heart group (29.8 +/- 0.9 vs 45 +/- 0.4 minutes, P <.05). Similarly, the need for transfusion was significantly less in the beating heart group (beating heart operations, 34%; cardiopulmonary bypass, 66%; P <.005). Reduced use of postoperative intra-aortic counterpulsation, as well as a lower rise in creatine kinase MB isoenzyme, was observed in the beating heart group. Operative mortality rates (beating heart operations, 1. 3%; cardiopulmonary bypass, 2%) and perioperative myocardial infarction (beating heart operations, 3.6%; cardiopulmonary bypass, 4.2%) were comparable for the two groups.

CONCLUSION

In a majority of patients, off-pump complete coronary artery revascularization is an acceptable alternative to conventional operations, yielding good results given progressive experience, rigorous technique, and adequate coronary artery stabilization.

Outcome analysis of coronary artery bypass grafting: minimally invasive versus standard techniques

Minimally invasive coronary artery bypass grafting (MIDCAB) procedures are purported to result in improvements in patient management over standard techniques. A comparative study was performed on risk-stratified patients treated with either technique. Following institutional review board approval, a retrospective random chart review was conducted on 27 MIDCAB and 37 standard coronary artery bypass grafting (CABG) patients who were operated on over a 12-month period at the University of Nebraska Medical Center. Risk stratification was accomplished by dividing the two patient populations, MIDCAB and 'standard', into one of four subgroups based on a preoperative risk score. Risk stratification was achieved by dividing the patient populations into one of four subgroups: good, fair, poor and high risk. Both groups received similar operations and surgical interventions, except for the inclusion of cardiopulmonary bypass (CPB). Approximately 200 parameters were collected and analyzed in the following categories: anthropometric, operative and postoperative outcomes. The MIDCAB group had a significantly lower number of vessels bypassed (2.0+/-0.7 vs 3.4+/-0.9, p < 0.0001). Total postoperative blood product transfusions trended higher in the standard group (6.1+/-12.6 U) when compared to the MIDCAB patients (2.3+/-5.5 U, p < 0.15), although not statistically significant. Postoperative inotrope use was significantly less in the MIDCAB group (19% vs 59%, p < 0.002). Ventilator time in the MIDCAB group was 10.5+/-5.4 h vs 15.0+/-12.3 h in the standard group (p < 0.07). The MIDCAB group had an overall greater length of stay, but was only statistically different within the poor-risk subgroup (12.2+/-10.7 vs 7.5+/-3.9, p < 0.04). The results of this study show that when CPB is not utilized in treating patients undergoing CABG procedures, the benefits in regards to patient outcomes are unclear. This necessitates the need for further work when comparing outcomes for risk-stratified patients.

Multivessel coronary artery bypass surgery without cardiopulmonary bypass

BACKGROUND

There is limited experience with complete myocardial revascularization on a beating heart. Using a mechanical stabilization system, we sought to determine if complete coronary revascularization is feasible without cardiopulmonary bypass and what the short-term clinical outcome would be.

METHODS

From February through September 1998, 26 patients underwent complete myocardial revascularization with Medtronics Octopus Tissue Stabilization System. Mean age for the group was 62 +/- 7 years (range 48 to 78 years); 11% had prior interventions. Mean preoperative ejection fraction was 49% +/- 14% (range 20% to 66%); 38% of operations were performed urgently. The mean number of vessels grafted was 3.0 +/- 0.9 (range 1 to 5 grafts/patient). In 96% of patients, at least one arterial graft was used. Fifteen percent of patients had 2 or more arterial grafts. In 58% of patients, a branch of circumflex coronary artery was bypassed.

RESULTS

The median time to extubation was 2 hours (range 0 to 37 hours). None of the patients had perioperative myocardial infarction, cerebrovascular accident, or renal failure requiring dialysis. The 30-day survival rate was 100%. Angiographic follow-up was not available. At a mean follow-up period of 3.8 +/- 2.9 months, all patients remained free of angina and none has required cardiac reintervention.

CONCLUSIONS

Complete myocardial revascularization on a beating heart can be achieved with the currently available stabilization systems and is associated with low perioperative complications and satisfactory short-term clinical outcomes. The long-term outcomes and graft patency remain to be determined.

Minimally invasive direct coronary artery bypass grafting using the gastroepiploic artery for reoperation after the Cabrol procedure

Obstruction of the right coronary ostial anastomosis is a rare late complication after composite graft replacement of the ascending aorta and the aortic valve with separate Dacron coronary grafts (Cabrol method). Occlusion at the right coronary ostial anastomosis in a 36-year-old woman with aortitis syndrome who underwent a composite graft with a Dacron coronary graft is described. She underwent a third successful operation for right coronary reconstruction by minimally invasive direct coronary artery bypass grafting technique using the right gastroepiploic artery. This approach is likely to be extremely useful in avoiding resternotomy and cardiopulmonary bypass in patients requiring coronary reoperation.

Exposure of circumflex branches in the tilted, beating porcine heart: echocardiographic evidence of right ventricular deformation and the effect of right or left heart bypass

OBJECTIVE

In off-pump coronary surgery, exposure of posterior vessels via sternotomy causes deterioration of cardiac function. Changes in ventricular geometry, valve competence, and hemodynamics after retraction of the beating heart were studied. Subsequently, the modifying effect of right or left heart bypass was investigated.

METHODS

In six 80-kg pigs, an ultrasound probe was attached to the backside of the left ventricle and the heart was fully retracted with a suction tissue stabilizer. Five pigs underwent additional pump support.

RESULTS

During retraction, the right ventricle was squeezed between the pericardium and interventricular septum, thereby decreasing its diastolic cross-sectional area by 62% +/- 6% (P <.001) while, concomitantly, right ventricular end-diastolic pressure increased to 165% +/- 19% (P =.004) of basal values. Stroke volume and mean arterial pressure decreased by 29% +/- 6% and 23% +/- 8% (P =.007 and P =.02, respectively). Left ventricular shape became somewhat elliptic without changes in preload pressure, and its diastolic cross-sectional area decreased by 20% +/- 3% (P =.001). All valves were competent. Right heart bypass restored left ventricular cross-sectional area, stroke volume, and mean arterial pressure. In contrast, left heart bypass increased blood pressure only marginally.

CONCLUSIONS

Ninety-degree anterior displacement of the beating porcine heart caused primarily right ventricular dysfunction as a result of mechanical interference with diastolic expansion without concurring valvular incompetence. Right heart bypass normalized stroke volume and mean arterial pressure by increasing left ventricular preload; in contrast, left heart bypass failed to restore systemic circulation.

Coronary artery bypass without cardiopulmonary bypass for patients with acute myocardial infarction

OBJECTIVE

Between January 1992 and December 1994, 57 patients having an acute myocardial infarction with coronary anatomy suitable for coronary artery bypass grafting without cardiopulmonary bypass underwent this procedure within 1 week of the infarction. We describe the surgical results of these high-risk patients.

METHODS

The study population included 43 male patients (75%) and 14 female patients (25%) whose mean age was 58.5 +/- 10.4 years. Thirty-two patients (56%) underwent emergency bypass grafting within 48 hours of an acute myocardial infarction, 4 of them (12.5%) as a bailout procedure after complicated percutaneous transluminal coronary angioplasty. Of these 32 patients, 7 patients (22%) were in cardiogenic shock, and 10 patients (31%) required preoperative intra-aortic balloon pump. Twenty-five patients (44%) underwent coronary bypass grafting 2 to 7 days after an acute myocardial infarction. The mean number of grafts per patient was 1.8 (range, 1-4), and the internal thoracic artery was used in 47 patients (82%). Only 7 patients (12%) received grafts to a circumflex marginal branch.

RESULTS

Operative mortality was 1.7% (1 patient), and the mean postoperative hospital stay was 6.8 +/- 3 days. One- and 5-year actuarial survivals were 94.7% and 82.3%, respectively. Angina returned in 7 patients (12%), 1 of whom underwent reoperation. Multivariate analysis revealed renal failure and preoperative cardiogenic shock to be independent predictors of overall mortality. Old myocardial infarction and operation within the first 48 hours were independent predictors of overall unfavorable outcome events.

CONCLUSIONS

These results suggest that coronary artery bypass grafting without cardiopulmonary bypass is a relatively low-risk procedure for patients having an infarction with coronary anatomy suitable for this technique.

Beating versus arrested heart revascularization: evaluation of myocardial function in a prospective randomized study

OBJECTIVE

Conventional coronary artery bypass grafting (CABG) is both safe and effective. Nevertheless, the use of cardiopulmonary bypass (CPB) and cardioplegic arrest are associated with several adverse effects. Over the last 2 years there has been a revival of interest in performing CABG on the beating heart. In this prospective randomized study we evaluated the efficacy and safety of on and off pump coronary revascularization on myocardial function.

METHODS

Eighty patients (65 males, mean age 61+/-9.7 years) undergoing first time CABG were prospectively randomized to: (i) conventional revascularization with CPB at normothermia and cardioplegic arrest with intermittent warm blood cardioplegia (on pump) or (ii) beating heart revascularization (off pump). Troponin I (Tn I) release was serially measured as a specific marker of myocardial damage. Haemodynamic measurements as well as inotropic requirement, incidence of arrhythmia and postoperative myocardial infarction were also recorded.

RESULTS

There were no significant differences between the two groups in terms of age, sex, extent of disease, left ventricular function and number of grafts. There were no deaths or intraoperative myocardial infarctions in either group. Tn I release was constantly lower in the off pump group and this was significant at 1, 4, 12 and 24 h postoperatively. Furthermore, in this group there was a significantly reduced incidence of arrhythmias. Inotropic requirements were less in the off pump group but this did not reach statistical significance.

CONCLUSION

These results suggest that off pump coronary revascularization is a safe and effective strategy for myocardial revascularization. Myocardial injury as assessed by Tn I release is also reduced when compared with conventional coronary revascularization with CPB and cardioplegic arrest.

Embracing the heart: perioperative management of patients undergoing off-pump coronary artery bypass grafting using the octopus tissue stabilizer

OBJECTIVE

To describe hemodynamic alterations during coronary artery bypass grafting (CABG) without extracorporeal circulation using the Octopus Tissue Stabilizer, and to describe the two anesthetic management protocols based on either general anesthesia with opioids (34 patients) or general anesthesia with high thoracic epidural anesthesia (TEA; 66 patients).

DESIGN

A prospective observational report.

SETTING

An academic university heart center.

PARTICIPANTS

First 100 patients undergoing CABG using the Octopus Tissue Stabilizer.

INTERVENTIONS

None.

MAIN RESULTS

Current management provided satisfactory results in preventing hypoperfusion of the heart and inadequate systemic circulation without the use of major pharmacologic interventions. Movement of the heart to reach the target site of anastomosis caused hemodynamic alterations. These could easily be corrected by anesthetic interventions, such as fluid load and low doses of inotropes. High TEA allows earlier extubation compared with the opioid anesthesia technique (0.9 v 4.5 hours). Perioperative management and the incidence of postoperative complications did not differ between anesthetic techniques. Major complications, such as death, intraoperative myocardial infarction, and stroke, did not occur.

CONCLUSION

Both anesthetic protocols are safe and effective in handling these patients. Off-pump CABG surgery requires anesthetic interventions because hemodynamic alterations are caused by the presentation of the heart to the surgeon. The complication rate is low but needs to be evaluated, compared with conventional CABG, in a prospective randomized study. High thoracic epidural anesthesia allows early recovery, but improved outcome could not be proved in this patient group.

Myocardial metabolism and hemodynamics during coronary surgery without cardiopulmonary bypass

BACKGROUND

Although renewed interest has recently been shown in coronary artery bypass grafting without cardiopulmonary bypass, no reports are available on myocardial metabolism and hemodynamics during temporary coronary occlusion and rotation of the contracting heart.

METHODS

Changes in myocardial energy metabolism and hemodynamics were monitored in 12 patients undergoing elective coronary artery bypass grafting without cardiopulmonary bypass, and the postoperative efflux of creatine kinase-MB mass and troponin T were also determined.

RESULTS

There was a significant increase in myocardial production of ATP degradation products (p = 0.026) and lactate (p = 0.004) during the operation. Myocardial oxygen extraction decreased (p = 0.012) in correlation with use of the short-acting beta-blocker, esmolol (r = -0.71). Apart from a decrease in mean arterial blood pressure (p = 0.002), there were no significant hemodynamic changes during the operation. The overall postoperative troponin T and creatine kinase-MB mass changes remained nonsignificant during the first two postoperative days. One patient had a myocardial infarction, diagnosed by electrocardiography, on the second postoperative day, but otherwise there were no major complications.

CONCLUSIONS

Coronary artery bypass grafting without cardiopulmonary bypass seems to be well tolerated as only minor changes in myocardial energy metabolism and hemodynamics are observed during the operation.