Con: beating-heart surgery for coronary revascularization: is it the most important development since the introduction of the heart-lung machine?

Methodological approach in adopting off-pump coronary artery bypass surgery in a British cardiothoracic unit: Harefield experience

The theoretical and practical disadvantages of coronary artery bypass graft surgery using cardiopulmonary bypass with cardioplegic arrest are well reported in the literature. Encouraged by our work and others, we adopted a systematic approach to the application of off-pump coronary artery bypass surgery. We aimed to validate the non-selective use of the off-pump technique in all patients and assess the outcome in specific patient groups including: patients with ischaemic left ventricular dysfunction, female and high-risk patients. We investigated specific technical details related to off-pump surgery including: the potential effect of the distortion of the mitral valve on haemodynamic stability intraoperatively and the feasibility of sequential coronary artery bypass grafting using the off-pump technique. We also compared the outcome to the national United Kingdom performance in a risk-stratified manner. An extensive retrospective data review for comparative analysis of outcome was carried out at both local and multi-centre levels. This showed that off-pump surgery was feasible for all patients, and provided a better outcome in patients with ischaemic left ventricular dysfunction, female and high-risk patients. The distortion of the mitral valve contributed to the haemodynamic instability. In conclusion, off-pump surgery is safe and provides better outcome in specific patient groups.

Impact of off-pump coronary artery bypass grafting on survival: current best available evidence

The superiority of either off-pump (OPCAB) or on-pump (ONCAB) coronary artery bypass grafting (CABG) remains unclear despite a large body of literature evidence comparing the two approaches. The potential advantages of avoiding cardiopulmonary bypass (CPB), minimizing aortic manipulation and maintaining pulsatile flow may be associated with reduced inflammatory responses and embolic events. Numerous studies compared OPCAB with ONCAB and the cumulative data have been presented in meta-analyses of both randomized and observational studies. Although there is an abundance of data with respect to the operative morbidity and mortality and the short-term outcomes associated with these two strategies, not much is known about how they impact long-term survival and recurrence of myocardial ischaemic events. Recent studies and meta-analyses have focused on long-term survival and major secondary outcomes in OPCAB vs. ONCAB within the general population. Significant limitations in methodology, however, have raised concerns about the strength of several randomized trials with restrictive inclusion criteria that reduced the populations to those at low risk only, thus creating result bias. Here, we present a review of the best available evidence with a focus on long-term outcomes.

Off-Pump Coronary Artery Bypass Surgery

Off-pump coronary artery bypass surgery has been adopted enthusiastically worldwide. However, despite more than 6 years’ experience and refinement, many surgeons use it only sporadically and some hardly at all. This reluctance persists despite support for the procedure because of the lack of properly designed risk models and/or randomized studies. Although it has not been overwhelmingly shown that off-pump surgery is superior to the conventional on-pump procedure, the technique has its place in our specialty. It has been shown to be better for noncritical end points in selected patients in the hands of selected surgeons. That there are differences in surgical skill among surgeons is something we all know but rarely discuss in public. Until now, disparities in skill have been most salient with uncommon and extraordinarily challenging operations. Perhaps the off-pump procedure should be regarded as the “challenging” aspect of coronary artery bypass surgery, and self-restraint may need to remain in force if we are to continue to achieve the highest level of clinical excellence.

Robot-assisted coronary artery bypass grafting improves short-term outcomes compared with minimally invasive direct coronary artery bypass grafting

BACKGROUND

Robot-assisted coronary artery bypass grafts (RACAB) utilizing the da Vinci surgical system are increasingly used and allow the surgeon to conveniently harvest internal mammary arteries (IMAs). The aim of this study was to compare the outcomes of off-pump RACAB and minimally invasive direct coronary artery bypass grafting (MIDCAB) in the short and medium term.

METHODS

We performed a retrospective review of 132 patients with single- or multiple-vessel coronary artery disease who underwent minimally invasive off-pump CABG (OPCAB) between May 2009 and May 2014. The patients were divided into two groups based on the surgical approach, MIDCAB and RACAB group. The anastomosis of the left internal mammary artery (LIMA) to the left anterior descending artery (LAD) was performed as regular OPCAB through the incision on the beating heart using regular stabilization devices (Genzyme Corporation). The preoperative, intraoperative, postoperative, and follow-up data, including major adverse cardiac and cerebrovascular events (MACCE), were compared.

RESULTS

The preoperative data were similar. RACAB significantly shorten the intensive care unit (ICU) stay and postoperative compared with the MIDCAB group (P<0.05). There were 12 (19.7%) patients treated with a two-stage hybrid procedure in the MIDCAB group and 34 (47.9%) patients in the RACAB group (P=0.001). Thirty-day mortality was 1.6% in the MIDCAB group. There were 9 (14.7%) MIDCAB patients and 2 (2.8%) RACAB patients (P=0.013) that developed new arrhythmia. The two groups showed comparable mid-term survival (P=0.246), but the MACCEs were significantly different (P=0.038).

CONCLUSIONS

RACAB may be a valuable alternative for patients requiring single or simple multi-vessel coronary artery bypass grafting (CABG). Although the mid-term mortality outcomes are similar, RACAB improves short-term outcomes and mid-term MACCE-free survival compared with MIDCAB.

Effects of Cardiopulmonary Bypass on Mediastinal Drainage and the Use of Blood Products in the Intensive Care Unit in 60- to 80-Year-Old Patients Who Have Undergone Coronary Artery Bypass Grafting

OBJECTIVE

The present study consisted of patients who underwent on-pump coronary artery bypass grafting (CABG) and off-pump CABG and investigated effect of using cardiopulmonary bypass (CPB) on the amount of postoperative drainage and blood products, red blood cell (RBC), free frozen plasma (FFP) given in the intensive care unit in 60-80-year-old patients who underwent CABG.

METHODS

The present study comprises a total of 174 patients who have undergone coronary artery bypass graft (off-pump or on-pump CABG) surgery in our clinic in between 2012-2015 year.

RESULTS

It was observed that the amount of drainage in the first 24 postoperative hours was lower in the on-pump CABG group (Group 1) when compared to off-pump group (Group 2) (Group 1 vs. Group 2; 703.5±253.8 ml vs. 719.6±209.4 ml; P =0.716). However, the amount of drainage in the second 24 hours was statistically significantly lower in the off-pump CABG group (Group 1 vs. Group 2; 259.8±170.6 ml vs. 190.1±129.1 ml; P =0.016). With regard to the amount of overall drainage, no statistically significant difference was observed between the two groups. Group 1 needed RBC transfusion higher than Group 2 (Group 1 vs. Group 2; 2.2±1.3 bag vs. 1.2±0.9 bag; P <0.001).

CONCLUSION

We can say that CPB influences the amount of second 24-hour drainage which indexed body surface area. In addition, CPB decreases hct, hb, thrombocyte count in ICU arrived, after 24 hours in postoperative period. Reduced thrombocyte counting effect can be appeared after 48 hours in the postoperative period of CPB.

Robot-assisted cardiac surgery

Recognition of the significant advantages of minimizing surgical trauma has resulted in the development of minimally invasive surgical procedures. Endoscopic surgery offers patients the benefits of minimally invasive surgery, and surgical robots have enhanced the ability and precision of surgeons. Consequently, technological advances have facilitated totally endoscopic robotic cardiac surgery, which has allowed surgeons to operate endoscopically rather than through a median sternotomy during cardiac surgery. Thus, repairs for structural heart conditions, including mitral valve plasty, atrial septal defect closure, multivessel minimally invasive direct coronary artery bypass grafting (MIDCAB), and totally endoscopic coronary artery bypass graft surgery (CABG), can be totally endoscopic. Robot-assisted cardiac surgery as minimally invasive cardiac surgery is reviewed.

Ultra-minimally invasive cardiac surgery: robotic surgery and awake CABG

The recognition of the significant advantages of minimizing surgical trauma has resulted in the development of minimally invasive surgical procedures. Endoscopic surgery confers the benefits of minimally invasive surgery upon patients, and surgical robots have enhanced the ability and precision of surgeons. Consequently, technological advances have facilitated totally endoscopic robotic cardiac surgery, which has allowed surgeons to operate endoscopically, rather than through a median sternotomy, during cardiac surgery. Thus, repairs for structural heart conditions, including mitral valve plasty, atrial septal defect closure, multivessel minimally invasive direct coronary artery bypass grafting and totally endoscopic coronary artery bypass graft surgery (CABG), can be totally endoscopic. On the other hand, general anesthesia remains a risk in patients who have severe carotid artery stenosis before surgery, as well as in those with a history of severe cerebral infarction or respiratory failure. In this study, the potential of a new awake CABG protocol using only epidural anesthesia was investigated for realizing day surgery and was found to be a promising modality for ultra-minimally invasive cardiac surgery. We herein review robot-assisted cardiac surgery and awake off-pump coronary artery bypass grafting as ultra-minimally invasive cardiac surgeries.

Robot-assisted minimally invasive direct coronary artery bypass grafting. ThoraCAB

BACKGROUND

 The aim of this study was to assess the outcome of robot-assisted minimally invasive direct coronary artery bypass grafting (MIDCAB), which is also termed "ThoraCAB".

METHODS AND RESULTS

 From 2005 to 2013, 35 consecutive patients underwent MIDCAB via a small thoracotomy on a beating heart. Before performing MIDCAB, the internal thoracic arteries (ITAs) were endoscopically harvested through 3 ports using the da Vinci Surgical System in a completely skeletonized fashion. Distal anastomosis was hand-sewn using a vacuum stabilizer, and a coronary artery active perfusion system was used to prevent myocardial ischemia during anastomosis. Successful robot-assisted ITA harvesting was achieved in all patients. There was an average of 1.7±0.8 grafts (range, 1-3 grafts) per patient. No patient needed mechanical ventilation for more than 24h. There were no deaths, strokes or myocardial infarctions, and none of the patients required conversion to median sternotomy.

CONCLUSIONS

 Robot-assisted ITA harvesting is safe and feasible. ThoraCAB is a relatively simple procedure and allows multivessel bypass grafting after a small thoracotomy. Therefore, it is expected that ThoraCAB will become the standard procedure for minimally invasive coronary revascularization and will be used in totally endoscopic CABG in the future. 

Landiolol reduces coronary artery motion in an open-chest porcine model: implications for off-pump coronary artery bypass surgery

Reduction of target coronary artery motion is imperative for successful off-pump coronary artery bypass surgery. We hypothesized that landiolol, a novel ultra-short-acting selective β-1 blocker, would reduce such coronary artery motion. To test this hypothesis, the motion of the left anterior descending artery of the porcine heart (n = 8) was analyzed by three-dimensional digital motion capture and reconstruction technology with or without continuous landiolol infusion. Landiolol (0.12 mg/kg/min) significantly decreased the heart rate (105 ± 16 vs. 90 ± 9 beats/min), three-dimensional distance moved (-20.4% vs. control), maximum velocity (-30.0% vs. control), acceleration (-31.1% vs. control), and deceleration (-28.6% vs. control) without inducing a significant change in the systolic blood pressure (85 ± 18 vs. 81 ± 22 mmHg), cardiac output (4.3 ± 1.4 vs. 4.1 ± 1.3 l/min), or pulmonary wedge pressure (7.8 ± 3.0 vs. 8.7 ± 2.9 mmHg). Landiolol reduces the heart rate and coronary artery motion with stable hemodynamics, which may facilitate performing precise anastomosis on the beating heart.

Selective beta-1 receptor blockade further reduces the mechanically stabilized target coronary artery motion during beating heart surgery

OBJECTIVE

Adequate stabilization of anastomosis sites during off-pump coronary artery bypass is essential to obtain excellent graft patency. We examined the effect of beta-1 adrenergic receptor blockade on the target coronary artery motion by three-dimensional (3D) digital motion capture and reconstruction technology.

METHODS

Eight pigs underwent a sternotomy. Reflection markers were attached to the surface coronary arteries, followed by a mechanical stabilizer application. Two high-speed digital cameras captured two-dimensional (2D) motion of the markers from different angles. These 2D data were reconstructed into 3D data points, representing the motion of each coronary artery. Landiolol hydrochloride, a novel selective beta-1 receptor blocker, was infused intravenously after acquisition of control data.

RESULTS

Beta-1 receptor blockade decreased heart rate (105 ± 16 vs. 90 ± 9 beat/min; P = 0.007) without decreasing arterial blood pressure. The 3D distance moved (millimeter) during one cardiac cycle was significantly reduced on the left anterior descending (9.6 ± 2.8 vs. 6.6 ± 1.9 mm; P = 0.003), left circumflex (10.5 ± 6.3 vs. 6.4 ± 2.6 mm; P = 0.038), and right coronary (8.3 ± 3.6 vs. 6.5 ± 2.1 mm; P = 0.028) arteries. Reduction in the maximal velocity, maximal acceleration, and maximal deceleration of the anastomosis site in all coronary arteries was also found in a quantitative fashion.

CONCLUSIONS

Selective beta-1 receptor blockade significantly reduces the 3D motion at anastomosis sites on the beating heart, with stable systemic blood pressure. Further quantitative investigations of pharmacological stabilization are warranted to achieve better outcome of the patients undergoing off-pump coronary artery bypass surgery.

Role of procurement-related injury in early saphenous vein graft failure after coronary artery bypass surgery

Saphenous vein graft thrombosis after coronary artery bypass graft surgery is a poorly understood problem that lessens the benefits of this procedure. Recent studies highlight the importance of injury sustained at the time of saphenous vein graft procurement in the pathogenesis of acute graft thrombosis. In particular, damage to the graft endothelium that occurs secondary to ex vivo pressure distention, a common practice during vein harvest, leads to a loss of antithrombotic factors and increased activity of subendothelial prothrombotic factors. The prothrombotic potential of damaged grafts is further exacerbated by an ischemic storage interval and subsequent exposure to arterial flow conditions after grafting. A clearer understanding of the mechanisms by which endothelial disruption leads to acute saphenous vein graft thrombosis may result in interventions for improving our procurement techniques, interrupting the downstream effects of the damaged saphenous vein graft and/or discriminating damage that is beyond an acceptable threshold of thrombotic risk.

Rationale, design and methodology for a Prospective Randomized Study of graft patency in Off-pump and On-pump MultI-vessel coronary artery bypasS Surgery (PROMISS) using multidetector computed tomography

Background

Off-pump coronary artery bypass grafting has been accused of possibly compromising graft patency. Sixteen slice computed tomography has shown good diagnostic accuracy in the assessment of coronary bypass graft patency when compared with conventional coronary artery angiography and is less invasive. The study hypothesis is that coronary artery bypass grafting (CABG) performed without cardiopulmonary bypass (Off-Pump) has equivalent early graft patency as if performed with cardiopulmonary bypass (On-Pump) and may have reduced complication rate.

Methods/Design

The Prospective Randomized Comparison of Off-Pump and On-Pump MultI-vessel Coronary Artery BypasS Surgery (PROMISS) is a controlled, single blinded, single centre clinical trial, comparing early graft patency using 16-slice computed tomography in patients with multi-vessel coronary artery disease operated either without or with extracorporeal circulation. Inclusion criteria are multivessel disease with an indication for first time, isolated, non emergent coronary artery bypass grafting with a minimum of three distal anastomoses. Secondary end points are peri-operative mortality, combined morbidity, length of stay, neuro-cognitive testing at 6 weeks and adverse events, stress test and quality of life at 6 months and one year. The sample size of one hundred and fifty patients was calculated in order to enable the detection of a 5% difference in graft patency, with 80% power, considering a minimum of 3 distal anastomoses per patient. Enrolment started in April 2005 and ended July 2007 with study closure in July 2008.

Conclusion

The PROMISS trial aims to shed new light on the effect of Off-Pump as compared to On-Pump coronary artery bypass surgery on graft patency, assessed by multidetector computed tomography, in unselected patients with multivessel coronary artery disease.

Trial Registration

Current Controlled Trials ISRCTN58800729

Current Status of Off-Pump Coronary Artery Bypass Surgery

The expanding indications for angioplasty coupled with the successful short and mid-term results of randomized controlled trials of drug-eluting stents have already had an unquestionable impact on the practice of coronary revascularization operations. However, coronary artery bypass grafting remains a major mode of therapy for coronary artery disease. It is likely that surgery will continue to be preferred for more complex subsets and that surgeons will have to continue to maintain good results in patients with more complex problems. Concerns regarding morbidity associated with conventional surgical myocardial revascularization on cardiopulmonary bypass have led to a resurgence of interest in off-pump bypass surgery during the last decade, with the expectation that it would be safer if cardiopulmonary bypass could be avoided. This review summarizes the impact of off-pump bypass surgery in reducing the morbidity and mortality associated with conventional coronary artery bypass on cardiopulmonary bypass by evaluating the current best-available evidence from randomized controlled trials and meta-analyses comparing off-pump surgery with conventional bypass grafting.

Impact of off-pump coronary artery bypass surgery on graft patency: current best available evidence

For more than three decades cardiac surgeons have been used to perform delicate coronary anastomoses on cardiopulmonary bypass (CPB). However, the price of a still and bloodless field is ultimately paid by the patients in the form of sequelae of negative effects of CPB including blood trauma, activation of a series of inflammatory responses, nonpulsatile flow, and possible embolization of air or debris. In an attempt to avoid these deleterious effects of CPB, off-pump coronary artery bypass surgery (OPCAB) has been rediscovered and refined. Although abundant evidence is available to suggest that excellent results can be achieved when CPB is avoided, concerns have been raised about quality of anastomosis and graft patency rates after OPCAB surgery. We are currently practicing in an era of evidence-based medicine that mandates the prospective randomized controlled trial (RCT) as the most accurate tool for determining a treatment benefit compared with a control population. This review article attempts to evaluate the current best available evidence from RCTs on the impact of OPCAB surgery on graft patency.

Revascularization with off-pump coronary artery surgery: what appears new is actually the old rediscovered

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 artery bypass grafting. Several large retrospective analyses, meta-analyses, and the randomized trials that addressed different aspects of ONCAB and OPCAB to date have compared the two surgical strategies. It is suggested that patients may achieve an excellent outcome with either type of procedure, and individuals' outcomes more likely depend on factors other than whether they underwent ONCAB or OPCAB. Nevertheless, there appear to be trends in most studies. These trends include less blood loss and need for transfusion, less myocardial enzyme release up to 24 h, less early neurocognitive dysfunction, and less renal insufficiency after OPCAB and propensity to lower costs, thereafter proving OPCAB to be safe and clinically effective. Here, we review the physiological advantages and clinical outcomes of OPCAB for myocardial revascularization and examine whether either strategy is superior and in which patients.

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.

Why Is Off-Pump Coronary Surgery Uncommon in Canada? Results of a Population-Based Survey of Canadian Heart Surgeons

BACKGROUND

Off-pump coronary artery bypass (OPCAB) is proposed to improve clinical outcomes and decrease resource use. However, off-pump surgery is not widely used in Canada. The purpose of this study was to determine the current use of OPCAB in Canada and determine why surgeons have not adopted this technique.

METHODS AND RESULTS

The study was a population-based survey of all adult Canadian cardiac surgeons in practice >1 year. Eligible division heads and surgeons were contacted by mail. Of 19 806 isolated coronary bypass surgeries performed by respondents in Canada last year, 3164 (16.0%) were performed off-pump. More than 50% of Canadian surgeons performed OPCAB in <5% of coronary cases, and only 17% of surgeons performed OPCAB in >25% of coronary cases. Only 4 responding centers performed OPCAB in >25% of cases. Respondents were divided into those who performed <5% of cases off-pump (nonadopters), 5% to 25% off-pump (intermediate users), or >25% off-pump (enthusiasts). Mean number of distal anastomoses in off-pump cases were 1.7+/-0.6, 1.6+/-0.6, and 3.3+/-0.5 for nonadopters, intermediate users, and enthusiasts, respectively (P=0.001). Eleven percent of nonadopters, 55% of intermediate users, and 81% of enthusiasts believed OPCAB improved clinical outcomes (P<0.0001). Only 23% of all respondents felt OPCAB use would increase in the next 5 years.

CONCLUSIONS

Concerns regarding incomplete revascularization and lack of proven clinical benefit have limited OPCAB to being performed routinely by only a small number of surgeons in Canada.

Inflammatory response to cardiac surgery: cardiopulmonary bypass versus non-cardiopulmonary bypass surgery

Cardiac surgery has been routinely performed using cardiopulmonary bypass (CPB) ever since its clinical introduction during the 1950s. CPB is, however, associated with an intense inflammatory response because of conversion to laminar flow, blood contact with the artificial bypass surface, cold cardiac ischaemia and hypothermia. The inflammatory reaction can intensify to a systemic inflammatory response syndrome (SIRS) associated with serious morbidity and mortality. Strategies to suppress inflammation had some success but fell short of controlling SIRS. The development of cardiac immobilization techniques allowing complete revascularization has caused a renaissance of coronary artery bypass grafting surgery on the beating heart (OPCAB). This strategy avoids all inflammation caused by CPB and reduces the pro-inflammatory stimulus to sternotomy and the revascularization procedure itself. This review summarises the pathophysiological features of the inflammatory response to CPB, revisits therapeutic anti-inflammatory strategies designed to suppress CPB-induced inflammation and balances the clinical evidence available comparing off-pump and on-pump revascularization.

Comparison of off-pump and on-pump coronary artery bypass grafting in midterm results

OBJECTIVE

Off-pump coronary artery bypass grafting (OPCAB) has become a procedure of choice for surgical treatment of coronary artery disease. Although early advantages of OPCAB were confirmed in comparison with conventional on-pump coronary artery bypass grafting (CABG), late cardiac complications are still controversial. We examined midterm results of OPCAB compared with standard CABG.

METHODS

Between July 1997 and April 2002, 736 consecutive patients who underwent isolated CABG were retrospectively reviewed. The OPCAB group (Group I) comprised 357 patients (49%), and the on-pump CABG group (Group II) 379 patients (51%). Their preoperative, intraoperative, and follow-up data were analyzed.

RESULTS

The mean number of distal anastomoses and the early graft patency were not greatly different between the two groups. The actuarial survival rate at 3 years was not significantly different between Group I (98.3%) and Group II (98.2%) (p = 0.71). The frequency of cardiac events was 4.2%/patient-year in Group I and 2.6%/patient-year in Group II (p = 0.12). The actuarial event free rates were not different between the two groups (p = 0.61). The cardiac event free rates at 3 years were significantly (p = 0.011) higher in patients with complete revascularization (96.7%) than without complete revascularization in Group I (69.2%) and in Group II (92.7% versus 85.9%, p = 0.026).

CONCLUSIONS

Midterm clinical outcome in OPCAB is as good as conventional on-pump CABG. Incomplete revascularization caused cardiac events more frequently than complete revascularization both in OPCAB and on-pump CABG in the intermediate follow-up.

Off-pump versus on-pump coronary surgery: final results from a prospective randomized study PRAGUE-4

BACKGROUND

Off-pump coronary artery bypass surgery is becoming increasingly popular despite the lack of sufficient evidence from randomized trials. The aim of our prospective, randomized, single-center study was to examine the role of off-pump revascularization among nonselected patients.

METHODS

A total of 400 consecutive nonselected patients (mean age 63 years) scheduled for isolated coronary revascularization were randomized by a cardiologist into two groups: A (on-pump) and B (off-pump). The cardiac surgeon was allowed to change the operative technique at any time after randomization. The only exclusion criterion was an emergency procedure. The primary end point was any of the following within 30 days: death, myocardial infarction, stroke, or new renal failure requiring hemodialysis. The study was analyzed on the intention-to-treat principle.

RESULTS

The primary end point occurred in 4.9% of patients in group A versus 2.9% in group B (not significant). Mortality was 1.1% in group A versus 2.0% in group B (not significant). Preoperative crossover occurred in 5.4% of patients in each group (not significant). Intraoperative conversion was necessary in 9.8% of patients in group B versus 1.1% of patients in group A (p < 0.001). Group B patients had fewer distal anastomoses (2.3 versus 2.7 in group A; p < 0.001), less blood loss (560 versus 680 mL; p < 0.001), lower postoperative creatine kinase MB levels (0.15 versus 0.56 microkat/L; p < 0.001) and lower total hospital costs (3,451 versus 4,387; p < 0.001).

CONCLUSIONS

In our study off-pump technique was applicable in 85% of nonselected patients and is at least as clinically safe and effective as on-pump surgery.

Transit time flow measurement in on-pump and off-pump coronary artery surgery

OBJECTIVE

Transit time flow measurement is frequently used during coronary artery bypass with and without cardiopulmonary bypass to detect graft dysfunction resulting from technical errors.

METHODS

Intraoperative transit time flow measurement measurements of 896 patients requiring surgery for double- or triple-vessel disease were reviewed retrospectively. Six-hundred and ninety-five patients were operated on-pump (Group A: coronary artery bypass with cardiopulmonary bypass), and 201 patients off-pump (Group B: coronary artery bypass without cardiopulmonary bypass). Transit time flow measurement measurements were analyzed for mean flow (mL/min). In total, measurements of 2247 grafts were analyzed.

RESULTS

Transit time flow measurement flows were lower in coronary artery bypass without cardiopulmonary bypass patients (left internal thoracic artery to left anterior descending artery: Group A, 37 [31, 40] mL/min vs Group B, 24 [20, 26] mL/min; saphenous vein graft to left anterior descending artery: Group A, 46.5 [40, 56] mL/min vs Group B, 21 [14, 57] mL/min. Troponin I release was reduced in the coronary artery bypass without cardiopulmonary bypass patients, with median values of 7.8 [7.0, 8.3] microg/L in Group A and 1.2 [0.9, 2.3] microg/L in Group B.

CONCLUSION

Evaluation of transit time flow measurement is valuable in determining coronary graft patency after coronary artery bypass with cardiopulmonary bypass and coronary artery bypass without cardiopulmonary bypass. Decreased troponin I release suggests a myocardial benefit of coronary artery bypass without cardiopulmonary bypass compared to coronary artery bypass with cardiopulmonary bypass, although the intraoperative transit time flow measurement flow measurements are markedly lower.

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.

Off-pump coronary artery bypass grafting: not a flash in the pan

During the past decade, technical improvements have made off-pump coronary artery bypass operations a routine procedure. During this time, off-pump coronary artery bypass has been audited against conventional techniques by many observational, case-matched, and prospective randomized studies. There is evidence in the literature suggesting that off-pump coronary artery bypass operations reduce postoperative morbidity, organ dysfunction, and costs, without compromising midterm outcome compared with conventional coronary operations. The available evidence also supports the view that high-risk patients might benefit the most from revascularization on the beating heart. High quality follow-up data are still needed to assess the impact of off-pump coronary artery bypass operations on long-term clinical outcome.

Off-pump coronary revascularization: is it all that it's cracked up to be?

There has been a recent resurgence in the use of off-pump coronary artery surgery. This article provides the critical care nurse with information about the procedure.

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

BACKGROUND

Avoiding cardiopulmonary bypass in coronary artery bypass grafting is thought to reduce early mortality and morbidity.

METHODS

We used our prospective database to compare all patients having off-pump coronary surgery (n = 389) with those having on-pump coronary surgery (n = 2412) between March 15, 1995, and November 1, 2000. Patients were grouped by age (years) in decades (>90, 80-89, 70-79, 60-69, <60 years). The Northern New England risk model was applied. Thirty-two independent variables were entered into a stepwise logistic regression analysis with the end points being surgical mortality and postoperative stroke.

RESULTS

Patients undergoing off-pump operations were older (70.9 +/- 12 vs 68.1 +/- 11 years; P <.001), and their Northern New England predicted risk was higher (11.9% +/- 13% vs 9.2% +/- 10%; P <.001). However, patients having on-pump bypass had significantly more bypass grafts constructed (3.3 +/- 0.8 vs 1.9 +/- 0.8; P <.001) and triple-vessel coronary artery disease (58% vs 28%; P <.001). There were no significant differences in postoperative mortality, stroke rate, complications, and length of stay between the groups. Logistic regression analysis did not show that cardiopulmonary bypass was a risk factor for either surgical mortality (odds ratio, 1.08; P =.83) or stroke (odds ratio, 1.59; P =.27).

CONCLUSION

Off-pump coronary bypass did not reduce early mortality and morbidity. Early and late results should be compared in a prospective randomized study.

Early and midterm outcome after off-pump and on-pump surgery in Beating Heart Against Cardioplegic Arrest Studies (BHACAS 1 and 2): a pooled analysis of two randomised controlled trials

BACKGROUND

Although no randomised controlled trial has assessed the midterm effects of coronary-artery bypass surgery on the beating heart, this technique is being used in more and more patients. We did two randomised trials to compare the short-term morbidity associated with off-pump and on-pump myocardial revascularisation. Our aim was to pool the results to assess midterm outcomes.

METHODS

From March, 1997, to November, 1999, we randomly allocated 200 patients to off-pump and 201 to on-pump coronary surgery. In Beating Heart Against Cardioplegic Arrest Study (BHACAS) 1, we excluded patients who had had myocardial infarction in the past month or who required grafting of the circumflex artery distal to the first obtuse marginal branch. In BHACAS 2, we included such patients. Primary outcomes were all-cause mortality and cardiac-related events at midterm follow-up (1-3 years). Analysis was by intention to treat.

FINDINGS

Analyses of combined data from both trials showed the following risk differences with off-pump compared with on-pump surgery: atrial fibrillation -25% (95% CI -33% to -16%); chest infection -12% (-19% to -5%); inotropic requirement -18% (-25% to -10%); transfusion of red blood cells -31% (-41 to -21); and hospital stay longer than 7 days -13% (-21 to -5). Mean follow-up was 25 0 months (SD 9.1) for BHACAS 1 and 13.7 months (5 5) for BHACAS 2. Four (2%) of 200 patients in the off-pump groups died from any cause, compared with seven (3%) of 201 in the on-pump group (hazard ratio 0.57, 95% CI 0.17-1.96). 33 (17%) of 200 patients in the off-pump group died or had a cardiac-related event, compared with 42 (21%) of 201 in the on-pump group (0.78, 0 49-1.22).

INTERPRETATION

Off-pump coronary surgery significantly lowers in-hospital morbidity without compromising outcome in the first 1-3 years after surgery compared with conventional on-pump coronary surgery.

Conversion to off-pump coronary bypass without increased morbidity or change in practice

BACKGROUND

This article examines the feasibility of complete conversion from conventional coronary artery operation to routine off-pump coronary bypass operation.

METHODS

Data on our first 285 off-pump procedures using the Octopus system (Medtronic Inc, Minneapolis, MN) represent our learning curve. This is a complete experience in coronary bypass surgery over 16 months.

RESULTS

The cohort was nonselected. All patients had at least two-vessel disease. Eight hundred seven grafts were performed (mean, 2.8 per patient) of which 647 grafts (84%) were arterial (mean, 2.3 per patient). One hundred seventy nine patients (63%) underwent total arterial revascularization. Eight patients required cardiopulmonary bypass; all other operations were completed off-pump. Complications were: mortality, 3 patients (1.5%); renal failure, 24 patients (8%); stroke, 2 patients (< 1%); and atrial fibrillation, 60 patients (21%). The morbidity data and frequency of arterial grafting did not differ from that of 355 patients who underwent coronary bypass operations in a preceding 18-month period.

CONCLUSIONS

Complete shift from routine use of cardiopulmonary bypass to nonselective off-pump coronary bypass operation is possible with a low conversion rate and without an apparent increase in morbidity or change in technique. Whereas short-term safety and efficacy seem certain, studies of long-term outcome are necessary before the eventual role of off-pump coronary bypass in myocardial revascularization can be defined.

A new intracardiac microaxial pump: first results of a multicenter study

As coronary artery bypass grafting (CABG) surgery in the beating heart technique is progressing, new devices have been developed to overcome hemodynamic instabilities while tilting the heart for exposure of back wall vessels. A new device for in heart biventricular intracorporeal circulation was applied in 42 patients undergoing CABG surgery (Group 1). The control group consisted of 38 patients operated on using a conventional cardiopulmonary bypass setup (Group 2). The study protocol of the prospective, randomized multicenter study was approved by the local ethics committees. Patients were included following inclusion criteria and patient informed consent. Mean age, procedure time, mean arterial pressure (MAP), and hemolysis by means of plasma free hemoglobin (fHb) were assessed preoperatively, perioperatively, on postoperative Days 1 to 3, at discharge, and at a 3 month follow-up. The mean age was 62.1 (range 59-74) years (Group 1), 62.7 (range 48-72) years (Group 2); procedure time was 112 min +/- 31.9 min (Group 1), 137.4 min +/- 36.2 min (Group 2); and 2.3 +/- 0.6 (Group 1), 2.2 +/- 0.7 (Group 2), vessels were revascularized. The flow on pump was 3.7 (2.5/4.4) L/min (Group 1), 4.9 (3.6/6.2) L/min (Group 2) which resulted in a MAP of 69.8 (4.0/143) mm Hg (Group 1), 58.3 (5.3/94) mm Hg while assessing the vessels of the back wall. Hemolysis defined by fHB was lower than 20 mg/dl at all times pre- and postoperatively. Intraoperative maximum values were up to 100 mg/dl in 4 patients (2 in Group 1 and 2 in Group 2). Body mass index was 26.4 +/- 2.6 (Group 1), 27.9 +/- 3.2. New York Heart Association Class was II to III in both groups. There were no pump related life threatening or severe adverse events. Beating heart procedures with ICC can be reliably and safely achieved. As the device is easy to use, it may deserve a more widespread use in the future.

Beating heart surgery or conventional CABG: are neurologic outcomes different?

Although there has been much debate about the causes of neurologic complications associated with coronary artery bypass grafting (CABG), there is good evidence linking such complications with some of the pathophysiologic changes associated with use of conventional cardiopulmonary bypass (CPB). Several studies indicate that it is possible to significantly lower risk of stroke and other central nervous system (CNS) morbidity in patients undergoing CPB for CABG by application of selected techniques and equipment modifications. The resurgence of interest in coronary revascularization by using beating heart surgery (BHS) offers a unique opportunity to evaluate neurologic outcome independent of CPB. Currently, BHS would appear to significantly reduce morbidity in the elderly and to decrease the costs and resource use in coronary revascularization patients. It is hoped that by understanding the mechanisms of CNS injury associated with CABG, techniques can be developed to decrease the risk of neurologic injury associated with coronary revascularization, whether or not CPB is used. Definitive conclusions regarding outcomes after best practice CPB or BHS await large-scale, risk-stratisfied multicenter trials.