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

Impact of impaired renal function on kinetics of high-sensitive cardiac troponin following cardiac surgery

BACKGROUND

Impaired renal function can increase cardiac troponin levels due to reduced elimination, potentially affecting its diagnostic utility. Limited data exist on high-sensitivity cardiac troponin I (hs-cTnI) kinetics after cardiac surgery relative to renal function. This study evaluates how impaired renal function influences hs-cTnI kinetics following cardiac surgery, distinguishing between patients with and without postoperative myocardial infarction (PMI).

METHODS

We conducted a retrospective analysis of adult patients who underwent elective cardiac surgery at our hospital from January 2013 to May 2019. Serial hs-cTnI measurements were taken from baseline up to 48 h post-surgery. Renal function was assessed using the MDRD formula, defining impaired renal function as a GFR < 60 ml/min. Acute kidney injury (AKI) was based on postoperative creatinine levels, and PMI was defined by ARC-2 criteria. Predictors of long-term all-cause mortality were analyzed using Cox regression.

RESULTS

Out of 14,355 patients (51.4% CABG, 39.4% valvular procedures, 9.2% thoracic aortic procedures), 139 (1.0%) had PMI. Hs-cTnI levels were higher in patients with impaired renal function across the cohort and in those without PMI. However, in patients with PMI, hs-cTnI levels did not vary significantly with renal function. Elevated hs-cTnI ≥ 213 times the upper limit of normal was a significant predictor of long-term mortality regardless of renal function (hazard ratio: 1.28, 95% CI: 1.17-1.40, p < 0.001), but early postoperative hs-cTnI measures held poor discriminatory yield to predict PMI with an AUC of 0.55 (95% confidence intervals: 0.54-0.56).

CONCLUSION

Renal function and acute kidney injury affect hs-cTnI kinetics post-surgery only in patients without PMI. Elevated hs-cTnI remains a strong predictor of long-term mortality, independent of renal function, but early postoperative detection of PMI requires additional metrics, including ECG, transthoracic echocardiography (TTE), and signs of hemodynamic instability.

Cardiopulmonary bypass associated acute kidney injury: better understanding and better prevention

Cardiopulmonary bypass (CPB) is a common technique in cardiac surgery but is associated with acute kidney injury (AKI), which carries considerable morbidity and mortality. In this review, we explore the range and definition of CPB-associated AKI and discuss the possible impact of different disease recognition methods on research outcomes. Furthermore, we introduce the specialized equipment and procedural intricacies associated with CPB surgeries. Based on recent research, we discuss the potential pathogenesis of AKI that may result from CPB, including compromised perfusion and oxygenation, inflammatory activation, oxidative stress, coagulopathy, hemolysis, and endothelial damage. Finally, we explore current interventions aimed at preventing and attenuating renal impairment related to CPB, and presenting these measures from three perspectives: (1) avoiding CPB to eliminate the fundamental impact on renal function; (2) optimizing CPB by adjusting equipment parameters, optimizing surgical procedures, or using improved materials to mitigate kidney damage; (3) employing pharmacological or interventional measures targeting pathogenic factors.

The outcomes of three different techniques of coronary artery bypass grafting: On-pump arrested heart, on-pump beating heart, and off-pump

OBJECTIVE

Conventional coronary artery bypass grafting (CABG) or on-pump arrested heart CABG (ONCAB) is a standard and simple technique. However, adverse effects can occur due to the use of aortic cross-clamp and cardiopulmonary bypass. Performing off-pump CABG (OPCAB) aims to avoid these adverse effects but may result in incomplete revascularization. On-pump beating heart CABG (ONBHCAB) combines the benefits of both ONCAB and OPCAB. This study focuses on comparing the short- and long-term outcomes of different CABG techniques.

METHOD

Retrospective observational cohort included 2,028 patients who underwent ONCAB, OPCAB, and ONBHCAB. The short-term outcomes including postoperative ischemic injury, hemodynamic functions, and adverse events were compared. The long-term outcomes were overall survival and the occurrence of major adverse cardiovascular events (MACE). Propensity score matching ensured comparability among the three patient groups.

RESULTS

After matching, there were no differences in baseline characteristics. Regarding ischemic injury, OPCAB showed the lowest peak cardiac enzyme levels (all p≤0.001). There were no statistically significant differences in the change of hemodynamic function (cardiac index) between the three groups (p = 0.158). Ten-year survival for OPCAB, ONBHCAB, and ONCAB were 80.5%, 75.9%, and 73.7%, respectively. OPCAB was associated with a significant reduction in mortality risk and MACE when compared to others (Mortality HR = 0.33, p = 0.001, MACE HR = 0.52, p = 0.004).

CONCLUSION

OPCAB implementation resulted in a lower occurrence of postoperative ischemic injury than ONCAB and ONBHCAB. No differences in postoperative hemodynamic function in all three techniques were observed. OPCAB respectively were preferable techniques beneficial for long-term outcomes.

On-pump beating heart versus off-pump myocardial revascularization-a propensity-matched comparison

Objective

On-pump beating heart (OP-BH) coronary artery bypass grafting (CABG) is often undertaken as an alternative between off-pump coronary artery bypass (OPCAB) and conventional on-pump coronary artery bypass grafting (On-pump CABG), especially in India. However, outcome data following OP-BH surgery is sparse. The aim of this study was to compare the outcomes of OP-BH CABG with OPCAB.

Methods

From our institutional database, all patients undergoing OP-BH CABG (n = 531) were identified. A propensity-matched cohort undergoing OPCAB (n = 531) was identified from the database. Nearest neighbor matching technique was used and the groups were matched for variables including age, gender, body mass index, EuroSCORE, history of recent myocardial infarction or unstable angina, hypertension, peripheral vascular disease, chronic obstructive airway disease, diabetes, pre-op renal impairment, pre-op neurological events, and left ventricular function.

Results

The propensity-matched groups were well matched in terms of baseline characteristics. The mean EuroSCORE was 3.17 and 3.20 in the OP-BH and the OPCAB groups. The unadjusted 30-day mortality in the propensity-matched OPCAB group was 2.07% (11/531) while mortality in the on-pump beating heart group was significantly higher at 6.9% (37/531). Multivariate analysis showed that OP-BH CABG was an independent risk factor for 30-day mortality as well as major adverse post-operative outcomes including renal, neurological, and respiratory outcomes and post-operative atrial fibrillation.

Conclusions

OP-BH CABG is associated with worse clinical outcomes compared to patients undergoing OPCAB.

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

Background

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

Methods and Results

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

Conclusion

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

Shortening cardioplegic arrest time in patients undergoing combined coronary and valve surgery: results from a multicentre randomized controlled trial: the SCAT trial

OBJECTIVES

Combined coronary artery bypass grafting and valve surgery requires a prolonged period of cardioplegic arrest (CA) predisposing to myocardial injury and postoperative cardiac-specific complications. The aim of this trial was to reduce the CA time in patients undergoing combined coronary artery bypass grafting and valve surgery and assess if this was associated with less myocardial injury and related complications.

METHODS

Participants were randomized to (i) coronary artery bypass grafting performed on the beating heart with cardiopulmonary bypass support followed by CA for the valve procedure (hybrid) or (ii) both procedures under CA (conventional). To assess complications related to myocardial injury, we used the composite of death, myocardial infarction, arrhythmia, need for pacing or inotropes for >12 h. To assess myocardial injury, we used serial plasma troponin T and markers of metabolic stress in myocardial biopsies.

RESULTS

Hundred and sixty patients (80 hybrid and 80 conventional) were randomized. Mean age was 66.5 years and 74% were male. Valve procedures included aortic (61.8%) and mitral (33.1%) alone or in combination (5.1%). CA time was 16% lower in the hybrid group [median 98 vs 89 min, geometric mean ratio (GMR) 0.84, 95% confidence interval (CI) 0.77-0.93, P  = 0.0004]. Complications related to myocardial injury occurred in 131/160 patients (64/80 conventional, 67/80 hybrid), odds ratio 1.24, 95% CI 0.54-2.86, P  = 0.61. Release of troponin T was similar between groups (GMR 1.04, 95% CI 0.87-1.24, P  = 0.68). Adenosine monophosphate was 28% lower in the hybrid group (GMR 0.72, 95% CI 0.51-1.02, P  = 0.056).

CONCLUSIONS

The hybrid procedure reduced the CA time but myocardial injury outcomes were not superior to conventional approach.

TRIAL REGISTRATION

ISRCTN65770930.

Efficacy and effectiveness of on- versus off-pump coronary artery bypass grafting: A meta-analysis of mortality and survival

BACKGROUND

Despite many studies comparing on- versus off-pump coronary artery bypass graft (CABG), there is no consensus as to whether one of these techniques offers patients better outcomes.

METHODS

We searched PubMed from inception to June 30, 2015, and identified additional studies from bibliographies of meta-analyses and reviews. We identified 42 randomized controlled trials (RCTs) and 31 rigorously adjusted observational studies (controlling for the Society of Thoracic Surgeons-recognized risk factors for mortality) reporting mortality for off-pump versus on-pump CABG at specified time points. Trial data were extracted independently by 2 researchers using a standardized form. Differences in probability of mortality (DPM) were estimated for the RCTs and observational studies separately and combined, for time points ranging from 30 days to 10 years.

RESULTS

RCT-only data showed no significant differences at any time point, whereas observational-only data and the combined analysis showed short-term mortality favored off-pump CABG (n = 1.2 million patients; 36 RCTs, 26 observational studies; DPM [95% confidence interval (CI)], -44.8% [-45.4%, -43.8%]) but that at 5 years it was associated with significantly greater mortality (n = 60,405 patients; 3 RCTs, 5 observational studies; DPM [95% CI], 10.0% [5.0%, 15.0%]). At 10 years, only observational data were available, and off-pump CABG showed significantly greater mortality (DPM [95% CI], 14.0% [11.0%, 17.0%]).

CONCLUSIONS

Evidence from RCTs showed no differences between the techniques, whereas rigorously adjusted observational studies (with >1.1 million patients) and the combined analysis indicated that off-pump CABG offers lower short-term mortality but poorer long-term survival. These results suggest that, in real-world settings, greater operative safety with off-pump CABG comes at the expense of lasting survival gains.

Surgery for mitral regurgitation in patients with aortic root aneurysm: Transaortic or transseptal approach?

OBJECTIVE

Mitral regurgitation is common in patients with aortic root aneurysm. Mitral valve repair (MVP) or replacement (MVR) can be performed for these patients through either a transverse aortotomy (TA) or transseptal approach (TS). This study sought to compare the early outcomes of mitral valve surgery through the TA and TS approaches and decide which is optimal for this subset of patients.

METHODS

Between March 2013 and April 2015, we operated on 99 patients (81 males, 81.8%) with aortic root aneurysm who developed mitral regurgitation. Mean age was 47.8±16.5years. MVR was performed in 66 patients (TAR=27; TSR=39) and MVP in 33 (TAP=8; TSP=25). The baseline and operative outcomes data were compared between patients with MVR and MVP through the TA vs TS approaches.

RESULTS

Preoperatively, the mitral regurgitation area was significantly larger in the MVR than MVP groups (8.9±2.0 vs 7.8±3.8 cm², p=0.0009), and in the TSP vs TAP groups (8.5±4.1 vs 5.6±1.3cm², p=0.0049), but no significant difference was found between the TAR and TSR groups (8.7±2.2 vs 9.0±1.8cm², p=0.4681); the aortic sinus size was significantly larger in the TAR than TSR group (66.7±15.8 vs 52.1±8.8mm, p=0.0061). Subvalvular structure was preserved in 12 MVR patients (18.2%). In MVP patients, Kay annuloplasty was used in 11 (33.3%) and annuloplastic ring in 22 (66.7%). The times of cardiopulmonary bypass (CPB) and cross-clamp in patients with TA approach were significantly shorter compared to those with the TS approach (139±34 vs 176±38min, p=0.0001; 101±26 vs 129±31min, p=0.0002). No cases of mortality, stroke and renal failure occurred in the whole series. The amount of transfusion, lengths of ICU and hospital stay did not differ between patients with MVR and MVP, and between the TA and TS approaches.

CONCLUSIONS

Both the TA and TS approaches achieved good early outcomes in MV surgery for patients with root aneurysm. The transverse aortotomy was associated with shorter CPB and cross-clamp times. Surgical approaches should be selected according to the underlying mitral valve etiology and the size of the aortic root.

Off Pump Coronary Artery Bypass Graft Surgery Versus Conventional Coronary Artery Bypass Graft Surgery: A Systematic Review of the Literature

The recent development of off-pump coronary artery bypass (OPCAB) graft surgical techniques has led to numerous observational and several randomized trials that have investigated outcomes compared with the current gold standard of conventional on-pump coronary bypass (CCAB) graft surgery. This systematic review assesses the current randomized trials that compare OPCAB and CCAB. Numerous end points were investigated, including mortality, stroke, myocardial infarction, atrial fibrillation, blood transfusions, wound infections, and renal failure. In addition to these important outcomes, resource utilization markers were also examined such as hospital length of stay, intensive care unit length of stay, and duration of intubation/ventilation. Finally, when level I evidence from randomized trials was unavailable, level II evidence was examined. This was done for subgroup analysis, where currently no randomized trials exist, looking at OPCAB in high-risk patients. Recommendations were made as to who should receive OPCAB and the potential benefits in this patient population.

Equivalence of the Acute Cytokine Surge and Myocardial Injury after Coronary Artery Bypass Grafting with and without a Novel Extracorporeal Circulation System

Cardiopulmonary bypass (CPB) contributes to a morbidity-inducing systemic Inflammatory response after cardiac surgery. We compared this response in patients receiving coronary artery bypass grafting (CABG) with (CPB group; n = 7) or without (off-pump group; n = 8) the Minimal Extracorporeal Circulation (MECC®) system. Serum concentrations of tumour necrosis factor (TNF)-α, soluble TNF receptors, pro- and anti-inflammatory interleukins (ILs) and other myocardial injury markers were measured after anaesthetic induction, at 1 h, 4 h and 24 h after completing all anastomoses or serially. Soluble TNF receptor type I (sTNFRI) and IL-8 peaked early after CABG in both groups and did not decline. Serum sTNFRI was significantly higher in the CPB compared with the off-pump group at 1 h, whereas IL-8 was significantly lower in the CPB group throughout. The MECC® system, therefore, produces an equivalent acute cytokine response and degree of myocardial injury to off-pump CABG, and may be useful when CABG cannot be performed without CPB.

A comparison of off- and on-pump beating-heart coronary artery bypass surgery on long-term cardiovascular events

Objective

Our aim was to compare short-term outcomes and long-term major adverse cardiovascular event (MACE)-free survival and independent predictors of long-term MACE after off-pump (OPCAB) versus on-pump beating-heart (ONBHCAB) coronary artery bypass grafting (CABG).

Methods

We retrospectively reviewed data of all consecutive patients who underwent elective CABG, performed by the same surgeon, from January 2003 to October 2009. A propensity score analysis was carried out to adjust for baseline characteristics and a total of 398 patients were included: ONBHCAB (n = 181), OPCAB (n = 217).

Results

OPCAB was associated with significantly shorter ventilation times (p < 0.001), intensive care unit stay (p < 0.001) and hospital stay (p < 0.001). The total blood loss was significantly more in the ONBHCAB group (p < 0.001), and accordingly, the number of transfused blood units was significantly lower in the OPCAB group (p < 0.001). Incidence of peri-operative renal complications were significantly higher in the ONBHCAB group (p = 0.004). The OPCAB group showed significantly lower long-term MACE-free survival (p = 0.029). The mean number of transfused blood units was the only independent predictor of MACE (HR: 1.218, 95% CI: 1.089–1.361; p = 0.001).

Conclusion

OPCAB provided better long-term MACE-free survival compared with ONBHCAB. Fewer units of blood transfused following OPCAB surgery may have been the main reason for this result.

Malignant ventricular arrhythmias after off-pump coronary artery bypass

BACKGROUND/PURPOSE

Sustained ventricular tachycardia and ventricular fibrillation (VT/VF) are rare complications after coronary surgery. Off-pump coronary artery bypass (OPCAB) was developed to decrease postoperative complications. No studies to date have specifically addressed VT/VF after OPCAB. We sought to assess the incidence, risk factors, and outcome of VT/VF after OPCAB.

METHODS

The study included a retrospective review of 1010 patients undergoing OPCAB between 2000 and 2012. Data were compared between the VT/VF patients and control patients who were the first cases of OPCAB in each month during the study period and did not have VT/VF.

RESULTS

Twenty-three patients (2.3%) developed VT/VF after OPCAB. The hospital mortality rate was 17.4%. In univariate analysis, the risk factors for VT/VF were old age, rapid heart rate, prolonged corrected QT interval, severe congestive heart failure, poor left ventricular ejection fraction, large left ventricular end-diastolic diameter, chronic kidney disease, preoperative dialysis, low blood hemoglobin level, preoperative intubation, recent myocardial infarction, high European System for Cardiac Operative Risk Evaluation, urgent/emergent operation, use of intra-aortic balloon pump, conversion to on-pump beating heart, postoperative dialysis, and no use of beta-blockers after operation. Multivariate analysis identified preoperative corrected QT interval > 426 milliseconds [odds ratio (OR) = 4.501; 95% confidence interval (CI) = 1.153-17.570] and estimated glomerular filtration rate < 30 mL/minute/1.73 m(2) (OR = 4.876; 95% CI = 1.112-21.374) as independent risk factors.

CONCLUSION

Postoperative VT/VF was rare after OPCAB but was associated with high mortality. Prolonged corrected QT interval and chronic kidney disease were independent risk factors. Recognition of these risk factors, proper prevention, and early intervention may improve survival.

Superior haemodynamic stability during off-pump coronary surgery with thoracic epidural anaesthesia: results from a prospective randomized controlled trial

OBJECTIVES

Off-pump coronary artery bypass (OPCAB) surgery is a technically more demanding strategy of myocardial revascularization compared with the standard on-pump technique. Thoracic epidural anaesthesia, by reducing sympathetic stress, may ameliorate the haemodynamic changes occurring during OPCAB surgery. The aim of this randomized controlled trial was to evaluate the impact of thoracic epidural anaesthesia on intraoperative haemodynamics in patients undergoing OPCAB surgery.

METHODS

Two hundred and twenty-six patients were randomized to either general anaesthesia plus epidural (GAE) (n = 109) or general anaesthesia (GA) only (n = 117). Mean arterial blood pressure (MAP), heart rate (HR) and central venous pressure (CVP) were measured before sternotomy and subsequently after positioning the heart for each distal anastomosis.

RESULTS

Both groups were well balanced with respect to baseline characteristics and received a standardized anaesthesia. The MAP decreased in both groups with no significant difference (mean difference (GAE minus GA) -1.11, 95% CI -3.06 to 0.84, P = 0.26). The HR increased in both groups after sternotomy but was significantly less in the GAE group (mean difference (GAE minus GA) -4.29, 95% CI -7.10 to -1.48, P = 0.003). The CVP also increased in both groups after sternotomy, but the difference between the groups varied over time (P = 0.05). A difference was observed at the third anastomosis when the heart was in position for the revascularization of the circumflex artery (mean difference (GAE minus GA) +2.09, 95% CI 0.21-3.96, P = 0.03), but not at other time points. The incidence of new arrhythmias was also significantly lower in the GAE compared with the GA group (OR = 0.41, 95% CI 0.22-0.78, P = 0.01).

CONCLUSION

Thoracic epidural with general anaesthesia minimizes the intraoperative haemodynamic changes that occur during heart positioning and stabilization for distal coronary anastomosis in OPCAB surgery.

Off-Pump coronary artery bypass surgery is associated with worse arterial and saphenous vein graft patency and less effective revascularization: Results from the Veterans Affairs Randomized On/Off Bypass (ROOBY) trial

BACKGROUND

The Department of Veterans Affairs Randomized On/Off Bypass (ROOBY) trial compared clinical and angiographic outcomes in off-pump versus on-pump coronary artery bypass graft (CABG) surgery to ascertain the relative efficacy of the 2 techniques.

METHODS AND RESULTS

From February 2002 to May 2007, the ROOBY trial randomized 2203 patients to off-pump versus on-pump CABG. Follow-up angiography was obtained in 685 off-pump (62%) and 685 on-pump (62%) patients. Angiograms were analyzed (blinded to treatment) for FitzGibbon classification (A=widely patent, B=flow limited, O=occluded) and effective revascularization. Effective revascularization was defined as follows: All 3 major coronary territories with significant disease were revascularized by a FitzGibbon A-quality graft to the major diseased artery, and there were no new postanastomotic lesions. Off-pump CABG resulted in lower FitzGibbon A patency rates than on-pump CABG for arterial conduits (85.8% versus 91.4%; P=0.003) and saphenous vein grafts (72.7% versus 80.4%; P<0.001). Fewer off-pump patients were effectively revascularized (50.1% versus 63.9% on-pump; P<0.001). Within each major coronary territory, effective revascularization was worse off pump than on pump (all P≤0.001). The 1-year adverse cardiac event rate was 16.4% in patients with ineffective revascularization versus 5.9% in patients with effective revascularization (P<0.001).

CONCLUSIONS

Off-pump CABG resulted in significantly lower FitzGibbon A patency for arterial and saphenous vein graft conduits and less effective revascularization than on-pump CABG. At 1 year, patients with less effective revascularization had higher adverse event rates.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00032630.

Off-pump versus on-pump coronary artery bypass grafting for ischaemic heart disease

BACKGROUND

Coronary artery bypass grafting (CABG) is performed both without and with cardiopulmonary bypass, referred to as off-pump and on-pump CABG respectively. However, the preferable technique is unclear.

OBJECTIVES

To assess the benefits and harms of off-pump versus on-pump CABG in patients with ischaemic heart disease.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) on The Cochrane Library (Issue 1, 2011), MEDLINE (OVID, 1950 to February 2011), EMBASE (OVID, 1980 to February 2011), Science Citation Index Expanded on ISI Web of Science (1970 to February 2011) and CINAHL (EBSCOhost, 1981 to February 2011) on 2 February 2011. No language restrictions were applied.

SELECTION CRITERIA

Randomised clinical trials of off-pump versus on-pump CABG irrespective of language, publication status and blinding were selected for inclusion.

DATA COLLECTION AND ANALYSIS

For statistical analysis of dichotomous data risk ratio (RR) and for continuous data mean difference (MD) with 95% confidence intervals (CI) were used. Trial sequential analysis (TSA) was used for analysis to assess the risk of random error due to sparse data and to multiple updating of accumulating data.

MAIN RESULTS

Eighty-six trials (10,716 participants) were included. Ten trials (4,950 participants) were considered to be low risk of bias. Pooled analysis of all trials showed that off-pump CABG increased all-cause mortality compared with on-pump CABG (189/5,180 (3.7%) versus 160/5144 (3.1%); RR 1.24, 95% CI 1.01 to 1.53; P =.04). In the trials at low risk of bias the effect was more pronounced (154/2,485 (6.2%) versus 113/2,465 (4.6%), RR 1.35,95% CI 1.07 to 1.70; P =.01). TSA showed that the risk of random error on the result was unlikely. Off-pump CABG resulted in fewer distal anastomoses (MD -0.28; 95% CI -0.40 to -0.16, P <.00001). No significant differences in myocardial infarction, stroke, renal insufficiency, or coronary re-intervention were observed. Off-pump CABG reduced post-operative atrial fibrillation compared with on-pump CABG, however, in trials at low risk of bias, the estimated effect was not significantly different.

AUTHORS' CONCLUSIONS

Our systematic review did not demonstrate any significant benefit of off-pump compared with on-pump CABG regarding mortality, stroke, or myocardial infarction. In contrast, we observed better long-term survival in the group of patients undergoing on-pump CABG with the use of cardiopulmonary bypass and cardioplegic arrest. Based on the current evidence, on-pump CABG should continue to be the standard surgical treatment. However, off-pump CABG may be acceptable when there are contraindications for cannulation of the aorta and cardiopulmonary bypass. Further randomised clinical trials should address the optimal treatment in such patients.

On-pump coronary surgery with and without cardioplegic arrest: comparison of inflammation, myocardial, cerebral and renal injury and early and late health outcome in a single-centre randomised controlled trial

OBJECTIVE

To assess the safety and efficacy of on-pump beating heart coronary surgery on organ function, and early and late health outcome as compared with conventional technique.

METHODS

A total of 81 patients were randomised to (1) coronary surgery with cardiopulmonary bypass (CPB) and cardioplegic arrest (CA) (on-pump with CA, n=41) or to (2) CPB without CA (on-pump without CA, n=40). Primary outcomes included serial measurement of interleukins (IL-6, IL-8 and IL-10) for inflammation, troponin I for myocardial injury, protein S100 for cerebral injury and creatinine clearance (CrCl) and urinary N-acetyl-β-d-glucosaminidase (NAG) for renal injury. In-hospital health outcome and 5-year event-free survival were secondary outcomes.

RESULTS

Baseline and intra-operative characteristics were similar between groups. A marked release of ILs was observed in both groups, but no significant differences between the groups were found (IL-6 +9%, 95% confidence interval (CI) -15% to +39%, p=0.49; IL-8 +4%, 95% CI -34% to +63%, p=0.86; IL-10 -0.1%, 95% CI -19% to +21%, p=0.93). Troponin I rose in both groups and was on average 34% higher in the on-pump without CA group but this did not reach statistical significance (95% CI -0.4% to +87%, p=0.08). S100 protein was higher in the on-pump without CA group at 12h (p=0.04) but did not differ at other times (p=0.16). The level of CrCl was higher 1h in the on-pump without CA group (+23%, 95% CI +1% to +50%, p=0.04), but not thereafter. NAG release was similar in both groups (+1% 95% CI -23% to +33%, p=0.91). Early and 5-year health outcomes were similar.

CONCLUSIONS

On-pump without CA coronary surgery does not provide any obvious advantage when compared with the conventional technique of on-pump with CA in elective patients. Both techniques provide a comparable degree of inflammatory activation, myocardial, cerebral and renal injury with similar 5-year event-free survival.

Postoperative Functional Outcome After Off-Pump Versus On-Pump Coronary Artery Bypass Grafting Using Gated Myocardial SPECT: A Comparison by Propensity Score Analysis

PURPOSE

We evaluated the short-term and mid-term differences in perfusion and function after off-pump and on-pump coronary artery bypass grafting (CABG) using gated myocardial single photon emission computed tomography.

MATERIALS AND METHODS

A total of 70 patients with coronary artery disease who underwent CABG were included based on the propensity score matching results from 165 patients. Thirty-five patients underwent off-pump and 35 patients on-pump CABG. Rest (201)Tl/dipyridamole stress (99 m)Tc-methoxyisobutylisonitrile gated single photon emission computed tomographies were performed preoperatively and postoperatively at short-term (103 ± 23 days after surgery) and mid-term follow-up (502 ± 111 days after surgery). Changes in left ventricular ejection fraction, end systolic volume, stress and rest segmental perfusion, and segmental wall thickening were compared between the two groups. The segments with preoperative rest (201)Tl uptake under 60% of maximum uptake were included in the segmental analysis.

RESULTS

Left ventricular ejection fraction (P = 0.001) and end systolic volume (P = 0.008) showed significant improvement in both groups. There were no significant short-term and mid-term differences between the two groups in terms of left ventricular ejection fraction (P = 0.309) and end systolic volume (P = 0.938). Likewise, segmental rest (P = 0.178) and stress perfusion (P = 0.071), and systolic wall thickening (P = 0.241) showed significant improvement in both groups with similar time courses.

CONCLUSION

Off-pump CABG resulted in significant improvements in left ventricular ejection fraction, end systolic volume, and regional myocardial perfusion and function that are comparable to on-pump CABG at short-term and mid-term. Gated myocardial SPECT successfully revealed that off-pump CABG is as good as on-pump CABG from the viewpoint of myocardial perfusion and function.

A randomized trial of on-pump beating heart and conventional cardioplegic arrest in coronary artery bypass surgery patients with impaired left ventricular function using cardiac magnetic resonance imaging and biochemical markers

BACKGROUND

Beating heart coronary artery bypass grafting (CABG) improves early postoperative cardiac function in patients with normal ventricular function, but its effect in patients with impaired function is uncertain. We compared a novel hybrid technique of on-pump beating heart CABG (ONBEAT) with conventional on-pump CABG (ONSTOP) in patients with impaired ventricular function.

METHODS AND RESULTS

In a single-center randomized trial, 50 patients with impaired ventricular function were randomly assigned to ONBEAT or ONSTOP. Patients underwent cardiac magnetic resonance imaging for function and delayed hyperenhancement early and later after surgery. Serial assessment of biochemical markers was also undertaken. Preoperative characteristics were well matched; cardiac index was 2.85+/-0.53 (ONBEAT) and 2.62+/-0.59 L x min(-1) x m(-2) (ONSTOP). Early after surgery, there was a trend toward a greater reduction in end-systolic volume index in ONSTOP patients versus ONBEAT (-9+/-8 versus -4+/-11 mL x m(-2); P=0.06). The changes were sustained and significant at 6 months (-14+/-18 versus -2+/-19 mL x m(-2); P=0.04). Furthermore, the incidence of new hyperenhancement at 6 days was higher in ONBEAT patients (P=0.05), with 6 of 17 (35%) sustaining 8.2+/-5.2 g of new hyperenhancement each versus 2 of 23 (9%) in the ONSTOP group, each with 9.8+/-9.0 g (P=0.86). Finally, median area under the curve for troponin was higher in ONBEAT at 461 (interquartile range, 226 to 1141) microg/L versus 160 (interquartile range, 98 to 357) microg/L for ONSTOP (P=0.002).

CONCLUSIONS

The incidence of new irreversible myocardial injury was significantly higher in ONBEAT than in ONSTOP patients. Furthermore, at 6 months, only ONSTOP patients demonstrated an improvement in ventricular geometry. The most likely mechanism is inadequate coronary perfusion to distal myocardial territories in patients with severe proximal coronary disease.

Using decision-analysis and meta-analysis to predict coronary artery bypass surgical outcomes – a model for comparing off-pump surgery to miniaturized cardiopulmonary bypass circuits

Coronary artery bypass (CABG) surgery with cardiopulmonary bypass (CPB) has been the “gold standard” for many years. However, methods to conduct off-pump coronary artery bypass (OPCAB) surgery with a beating heart have decreased the use of CPB. Improvements in cardiopulmonary bypass technology, using low-prime circuits with retrograde autologous prime, have demonstrated a reduction in blood use while maintaining the surgical advantage of increased revascularization associated with on-pump surgery. A meta-analysis of published randomized clinical trials was used to compare the outcomes. These outcomes included the number of grafts, hospital length of stay, and transfusion rate. They were then incorporated into a decision-analysis model to compare OPCAB with the on-pump surgery, using both conventional high-prime (HP) and low-prime circuits with retrograde autologous prime (LP/RAP). The meta-analysis of randomized clinical trials revealed that OPCAB surgery had 0.33 less grafts (p < .05), a reduction of 0.97 days in hospital length of stay (LOS) (p < .05), and a 63.2% reduction in percentage of patients transfused (p < .05). Based on the decision-analysis model, a relatively low major event rate (defined as myocardial infarction, need for angioplasty or surgery) at 4 years of 2% can eliminate the savings associated with OPCAB when compared to a low-prime circuit with RAP. Using a 5% major event rate at 4 years, the predicted cost savings of LP/RAP over OPCAB is $510 per patient or $51,036,746 per 100,000 patients. The development and implementation of low-prime circuits with retrograde autologous prime is an import step in matching the outcomes associated with OPCAB surgery.

Clinical outcomes in randomized trials of off- vs. on-pump coronary artery bypass surgery: systematic review with meta-analyses and trial sequential analyses

AIMS

To assess the clinical outcomes of off- vs. on-pump coronary artery bypass surgery in randomized trials.

METHODS AND RESULTS

We searched electronic databases and bibliographies until June 2007. Trials were assessed for risk of bias. Outcome measures were all-cause mortality, myocardial infarction, stroke, atrial fibrillation, and renewed coronary revascularization at maximum follow-up. We applied trial sequential analysis to estimate the strength of evidence. We found 66 randomized trials. There was no statistically significant differences regarding mortality [relative risk (RR) 0.98; 95% confidence interval (CI) 0.66-1.44], myocardial infarction (RR 0.95; 95% CI 0.65-1.37), or renewed coronary revascularization (RR 1.34; 95% CI 0.83-2.18). We found a significant reduced risk of atrial fibrillation (RR 0.69; 95% CI 0.57-0.83) and stroke (RR 0.53; 95% CI 0.31-0.91) in off-pump patients. However, when continuity correction for zero-event trials was included, the reduction in stroke became insignificant (RR 0.62; 95% CI 0.32-1.19). Trial sequential analysis demonstrated overwhelming evidence supporting that off-pump bypass surgery reduces atrial fibrillation.

CONCLUSION

Off-pump surgery reduces the risks of postoperative atrial fibrillation compared with on-pump surgery. For death, myocardial infarction, stroke, and renewed coronary revascularization, the evidence is still weak and more low-bias risk trials are needed.

Mid-term outcomes of off-pump versus on-pump coronary artery bypass graft surgery

OBJECTIVE

To evaluate survival and readmissions to hospital for cardiac events or coronary revascularization (REVASC) in patients having off-pump (OPCAB) versus conventional on-pump (CCAB) coronary artery bypass graft surgery (CABG).

METHODS

Of 11,368 consecutive patients undergoing isolated CABG between 1996 and 2002, 514 had OPCAB surgery. Using propensity scores, 503 CCAB patients were randomly matched to 503 OPCAB patients.

RESULTS

There were no clinical or statistical differences between the two groups for any prognostic variable. However, OPCAB patients received significantly fewer distal anastomoses than the CCAB group (2.6+/-1.0 versus 3.1+/-1.0; P<0.001). There was no difference in operative mortality (OPCAB 1.0%, CCAB 1.4%; P=0.6), but the OPCAB group had significantly fewer operative strokes (0.2% versus 1.8%; P=0.01). Follow-up was 99.7% complete at 2.2+/-1.2 years (range 0 to 6 years). Twice as many OPCAB patients (n=24) required REVASC compared with the CCAB (n=11) group. The following five-year actuarial outcomes are presented for CCAB and OPCAB, respectively: survival: 77+/-6%, 76+/-8%, P=0.8; freedom from REVASC: 95+/-3%, 92+/-2%, P=0.02; and cardiac event-free survival: 76+/-5%, 62+/-8%; P=0.05. Cox regression revealed that OPCAB was a significant independent predictor of poorer freedom from REVASC (RR 2.2, 95% CI 1.0 to 4.6; P=0.04) and cardiac event-free survival (RR 1.6, 95%CI 1.1 to 2.2; P=0.02).

CONCLUSIONS

The use of OPCAB remains controversial. These results, from this early experience, suggest that despite improved hospital outcomes, the lesser degree of REVASC raises concerns about the need for repeat revascularization in the OPCAB group.

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.

Inflammatory response and cardioprotection during open-heart surgery: the importance of anaesthetics

Open-heart surgery triggers an inflammatory response that is largely the result of surgical trauma, cardiopulmonary bypass, and organ reperfusion injury (e.g. heart). The heart sustains injury triggered by ischaemia and reperfusion and also as a result of the effects of systemic inflammatory mediators. In addition, the heart itself is a source of inflammatory mediators and reactive oxygen species that are likely to contribute to the impairment of cardiac pump function. Formulating strategies to protect the heart during open heart surgery by attenuating reperfusion injury and systemic inflammatory response is essential to reduce morbidity. Although many anaesthetic drugs have cardioprotective actions, the diversity of the proposed mechanisms for protection (e.g. attenuating Ca(2+) overload, anti-inflammatory and antioxidant effects, pre- and post-conditioning-like protection) may have contributed to the slow adoption of anaesthetics as cardioprotective agents during open heart surgery. Clinical trials have suggested at least some cardioprotective effects of volatile anaesthetics. Whether these benefits are relevant in terms of morbidity and mortality is unclear and needs further investigation. This review describes the main mediators of myocardial injury during open heart surgery, explores available evidence of anaesthetics induced cardioprotection and addresses the efforts made to translate bench work into clinical practice.

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.

The Best Bypass Surgery Trial: Rationale and design of a randomized clinical trial with blinded outcome assessment of conventional versus off-pump coronary artery bypass grafting

BACKGROUND

Recent trials suggest that off-pump coronary artery bypass grafting (OPCAB) reduces the risk of mortality and morbidity compared with conventional coronary artery bypass grafting (CCAB) using cardiopulmonary bypass. Patients with a moderate- to high-risk of complications after CCAB may have additional benefit from OPCAB.

METHODS

The Best Bypass Surgery Trial is a randomized, single center trial comparing the effects of OPCAB versus CCAB. The inclusion criteria are 3 vessel coronary heart disease affecting one of the marginal arteries, age>54 years, and EuroSCORE>or=5. The primary composite outcome measure consists of all-cause mortality, myocardial infarction, stroke, cardiac arrest, cardiogenic shock, and cardiac revascularization procedure. Follow up involves collection of data of mortality and morbidity via linkage to public registers, quality of life assessment at 3 and 12 months postoperatively and angiographic control at 12 months. The sample size of 330 patients was based on an estimated 75% one-year event free rate of the primary outcome measure in the OPCAB arm and 60% in the control arm with alpha=.05 and beta=.20. Accordingly, the trial will be able to detect an absolute risk reduction of 15% or a relative risk reduction of 37.5%. The median follow-up time is scheduled to 3 years.

RESULTS

Enrollment started in April 2002 and ended March 2006.

CONCLUSION

The results may have implications on the treatment modality of moderate- to high-risk patients scheduled for coronary artery bypass grafting.

On-Pump Beating-Heart Coronary Artery Bypass: A Propensity Matched Analysis

BACKGROUND

It remains unclear how cardioplegic arrest affects surgical results after coronary artery bypass grafting surgery (CABG). This study compares early outcomes after on-pump beating-heart CABG and conventional CABG.

METHODS

From 2002 to 2005, 114 patients underwent on-pump beating-heart CABG. Multivariate logistic regression revealed five characteristics according to which technique is liable to be used: history of cerebral infarction, urgent or emergent operation, lower ejection fraction, preoperative creatine kinase, and lower number of diseased vessels. The early clinical outcome for these patients was compared against 114 conventional CABG patients, matched using a propensity score constructed with these five significant variables and with two nonsignificant variables: history of diabetes mellitus and hypertension.

RESULTS

On-pump beating-heart CABG significantly reduced the duration of operation and cardiopulmonary bypass, total blood loss, and peak creatine kinase (p < 0.05). The number of patients requiring additional intra-aortic balloon pump support was significantly lower in the on-pump beating-heart CABG group (2 versus 13, p < 0.01). No patients required percutaneous cardiopulmonary support after on-pump beating-heart CABG, whereas 4 patients needed it after conventional CABG. Complete revascularization was significantly lower (42.1% versus 77.2%, p < 0.0001), but in-hospital mortality was less in the on-pump beating-heart CABG group (2.6% versus 9.6%, p < 0.05). No significant difference was found in morbidity including stroke, renal failure, mediastinitis, and prolonged ventilation.

CONCLUSIONS

On-pump beating-heart CABG can be performed safely, including on high-risk patients. Use of cardiopulmonary bypass and the elimination of cardioplegic arrest may be of most benefit to hemodynamically unstable patients.

Functional status of patients during subacute recovery from coronary artery bypass surgery

BACKGROUND

Patients recovering from coronary artery bypass (CAB) surgery are particularly vulnerable to impaired functional status because in addition to the direct effects of heart disease on cardiac performance, many surgical factors may contribute to loss of function.

OBJECTIVES

The purposes of this study were to describe functional status across multiple domains using performance-based and self-report assessments and to determine the relationship among different domains of functional status in patients recovering subacutely (<6 months) from CAB surgery.

METHODS

The participants in this study (n = 25) had undergone CAB surgery in the past 6 months. This cross-sectional descriptive study measured functional status in several domains using self-report and performance-based assessments.

RESULTS

The study results indicate that participants had deficits in health-related quality of life, activities of daily living performance, endurance/aerobic capacity, and cognitive/memory ability. Several correlations between the scores for outcome measures in different domains were found in this study.

CONCLUSIONS

Impaired functional status occurs in patients recovering subacutely from CAB surgery. Different aspects of functional status are related, and an understanding of these relationships may help to improve the medical management of patients after CAB surgery.

Coronary Artery Revascularization (CARE) Registry: An Observational Study of On-Pump and Off-Pump Coronary Artery Revascularization

BACKGROUND

The Coronary Artery Revascularization (CARE) study is a multicenter observational registry of coronary revascularization by percutaneous and surgical techniques. As a substudy of this registry, we analyzed the current practice and outcomes of on-pump and off-pump coronary artery bypass graft (CABG) surgery.

METHODS

Procedural and outcomes data were prospectively collected for all patients undergoing isolated CABG in eight community-based hospitals in the HCA Hospital System between February 1 and July 31, 2004. Twelve-month follow-up was obtained by patient contact, phone, questionnaire, and the National Death Index.

RESULTS

Isolated coronary artery revascularization procedures were done in 1251 patients, with 12-month follow-up data available on 1149 (91.8%); 654 patients (52.3%) were operated on-pump and 597 (47.7%) had off-pump procedures. On-pump versus off-pump results were mean number of grafts, 3.4 +/- 1 versus 2.9 +/- 1.2 (p < 0.001); operative mortality, 1.7% versus 1.7% (p = 1.00); permanent stroke, 0.9% versus 0.7% (p = 0.51); reoperation for bleeding, 2.6% versus 1.0% (p = 0.037); prolonged ventilation, 10.0% versus 3.4% (p < 0.001); atrial fibrillation, 23.8% versus 14.9% (p < 0.001); need for transfusion, 51.0% versus 34.9% (p < 0.001); intensive care unit length of stay, 68.1 +/- 97.0 hours versus 59.3 +/- 109.4 hours (p = 0.16); and hospital length of stay, 7.5 days versus 6.2 days (p < 0.001). At 12 months, there was no difference in total cardiac mortality on-pump versus off-pump (4.9% versus 4.6%, p = 0.88), myocardial infarction (1.0% versus 0.7%, p = 0.76), need for repeat revascularization (2.8% versus 4.1%, p = 0.70), or total overall major adverse cardiac outcomes (8.7 versus 9.4, p = 0.69).

CONCLUSIONS

Current approaches to coronary revascularization using both on-pump and off-pump techniques at individual surgeon discretion, which varies significantly in the community setting, leads to acceptable outcomes. Although perioperative complications were less off-pump, mortality was the same, both in the perioperative period and at 12 months. Fewer grafts in the off-pump group appeared to be related to disease burden and not incomplete revascularization. Cardiac death, myocardial infarction, and the need for repeat revascularization were equal at 12 months.

Markers for perioperative myocardial ischemia: what both interventional cardiologists and cardiac surgeons need to know

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

Off-Pump Surgery Is Associated With Reduced Occurrence of Stroke and Other Morbidity as Compared With Traditional Coronary Artery Bypass Grafting

Background and Purpose— There is growing enthusiasm for coronary artery bypass grafting (CABG) without cardiopulmonary bypass (CPB). Although deleterious effects of CPB are known, it remains to be proven that avoiding CPB will result in reduction in morbidity. We sought to determine whether off-pump surgery is associated with reduced occurrence of adverse outcomes as compared with CABG with CPB.

Methods— Studies were identified by searching the MEDLINE, EMBASE and the Cochrane Register 1980 to 2006 (February). We also searched the reference lists of randomized clinical trials (RCT) and reviews to look for additional studies. Study selection: RCTs comparing off-pump surgery to CABG with CPB. No restriction applied on the size of the trial or end point reports. Data extraction: 2 reviewers independently searched for studies, read abstracts and abstracted all data. Data synthesis: combined estimates were obtained using fixed or random effect meta-analyses. Relative risks and risk differences were calculated. Heterogeneity was assessed using χ 2 and I 2 values.

Results— There were 3996 patients enrolled in 41 RCTs (mean age 62, 22% female). No study reported information on race. Off-pump CABG was associated with a 50% reduction in the relative risk of stroke (95% CI, 7% to 73%), 30% reduction in atrial fibrillation (AF; 95% CI, 16% to 43%) and 48% reduction in wound infection (95% CI, 26% to 63%) with no heterogeneity among RCTs. This translated into avoidance of 10 strokes, 80 cases of AF and 40 infections per 1000 CABG. Fewer distal grafts were performed and there was evidence for >10 reinterventions per 1000 with off-pump CABG. Long-term follow-up is not yet reported in the trials.

Conclusions— Off-pump CABG is associated with reduced risk of stroke, AF and infections as compared with CABG with CPB. Evidence should be generalized taking into account RCT enrollment limitations, drawbacks related to training requirements, propensity to perform fewer grafts and likely reinterventions after off-pump surgery.

Off-pump coronary artery bypass grafting through sternotomy: for whom?

PURPOSE OF REVIEW

Off-pump coronary artery bypass grafting hopes to avoid morbidity associated with cardiopulmonary bypass, improving clinical outcomes. Yet its technical difficulty and unfamiliarity raise concern that adoption of off-pump coronary artery bypass might be associated with poorer outcomes. Both surgeon-specific and patient-related factors are believed to play roles in the success of off-pump coronary artery bypass. This review sought to elucidate these factors.

RECENT FINDINGS

Current prospective data suggest that both techniques have similar rates of mortality but off-pump coronary artery bypass does provide patients with a lower morbidity. Multiple prospective studies suggest a decrease in stroke rates for off-pump coronary artery bypass grafting. There is a consensus that certain patients will have better outcomes if done off-pump. Surgeon experience with the procedure does impact patient outcome.

SUMMARY

Though every patient must be dealt with on an individual basis, it would appear that almost any patient is a candidate for off-pump coronary artery bypass and that, given time and an appropriate desire, most any surgeon can perform the procedure.

Release of Brain Natriuretic-Related Peptides (BNP, NT-proBNP) and Cardiac Troponins (cTnT, cTnI) in On-pump and Off-pump Coronary Artery Bypass Surgery

BACKGROUND

We studied the kinetic release of cardiac troponins (cTnI and cTnT) and B-type natriuretic peptides (BNP and NT-proBNP) in patients undergoing off-pump or on-pump coronary artery bypass surgery.

METHODS

Twenty-five consecutive patients were prospectively enrolled. The patients were divided into three groups: beating heart (I), and cardiopulmonary bypass (CPB) with warm (II) or cold cardioplegia (III). Plasma samples were obtained before anesthesia induction until the sixth day after surgery.

RESULTS AND CONCLUSIONS

The data were analyzed first for off-pump versus the CPB procedures and second for warm versus cold cardioplegia. The plasma troponin releases appeared to be significantly higher in the CPB groups in comparison to the beating heart group (P < 0.001 and P < 0.002 for cTnI and cTnT peak values, respectively). The peak of the B-type natriuretic peptide release appeared to be more delayed in the groups undergoing CPB than in the beating heart group (day 6 versus days 2 and 4 for NT-proBNP and BNP, respectively). Taken together, our results indicated that the new generation of cTnT assays seemed to be more sensitive than the cTnI assays for the diagnosis of myocardium injury. A lower increase in the cTnT values in the warm cardioplegic group indicated less damage of the myocardium than with cold cardioplegia. Our data also confirm better preservation of the myocardium with off-pump cardiac surgery than with CPB.

Troponin T elevation after coronary bypass surgery: clinical relevance and correlation with perioperative variables

OBJECTIVE

Elevation in markers of myocardial necrosis is a common feature following coronary artery bypass surgery, but its relevance is unclear. The objective of this study was to evaluate the association between postoperative troponin T elevation, perioperative variables and clinical outcomes.

METHODS

We evaluated 100 low-risk patients undergoing first-time elective on-pump coronary artery bypass surgery. The mean age was 62 +/- 9.8 years and 83% were male; patients with diabetes mellitus, renal failure and impaired left ventricular function (ejection fraction < 40%) were excluded. Troponin levels were measured at baseline and 12 and 24 h following the onset of cardiopulmonary bypass. Predefined clinical endpoints included death, new Q waves on 12-lead electrocardiogram and inotropic requirement.

RESULTS

Postoperative troponin elevation occurred in 95%. Troponin T elevation was related to the duration of cardiopulmonary bypass (P = 0.0001) and aortic cross-clamp time (P = 0.0003). There was also an inverse relationship with perioperative core temperature (P = 0.0001). There was no association between postoperative troponin elevation and clinical outcomes.

CONCLUSIONS

Postoperative troponin T elevation occurs in the majority of patients undergoing elective on-pump coronary artery bypass surgery. In this low-risk cohort, troponin T elevation was associated with procedural duration but not with clinical outcome.

Early outcome of a randomized comparison of off-pump and on-pump multiple arterial coronary revascularization

BACKGROUND

Previous randomized comparisons of off-pump and on-pump coronary artery bypass grafting (CABG) have yielded controversial results about the cardiac and neurological events and graft patency. In addition, these randomized studies were composed of CABG with a few arterial grafts. We performed a prospective randomized controlled study to compare off-pump and on-pump CABG with multiple arterial grafts.

METHODS AND RESULTS

Between July, 2002, and September, 2004, 167 consecutive unselected patients referred for elective primary CABG were randomly assigned to undergo multiple arterial off-pump CABG (n=81) or on-pump CABG (n=86). The clinical outcomes and S-100 protein, neuron-specific enolase, and maximum creatine kinase-MB levels were compared. Early graft patency was examined within 3 weeks after the operation by angiography. The number of grafts performed per patient (3.5+/-1.0 for off-pump CABG and 3.6+/-0.9 for on-pump CABG) and the number of arterial grafts performed per patient (3.3+/-1.0 for off-pump CABG and 3.4+/-0.9 for on-pump CABG) were similar. Completeness of revascularization (completed grafts/planned grafts) was 98% in both procedures. There were no hospital deaths in either group. The operation time was significantly (P<0.001) shorter in the off-pump group than in the on-pump group (267+/-60 minutes versus 307+/-59 minutes). The incidence of perioperative complications was similar. The frequency of no need for transfusion was higher in the off-pump group than in the on-pump group (80% versus 55%, P<0.001). The S-100 protein levels at the admission into the intensive care unit were significantly (P<0.001) lower in the off-pump group than in the on-pump group (0.20+/-0.11 ng/mL versus 0.34+/-0.22 ng/mL). The neuron-specific enolase levels at the intensive care unit admission were significantly (P<0.001) lower in the off-pump group than in the on-pump group (10.4+/-9.0 ng/mL versus 16.9+/-6.9 ng/mL). Maximum creatine kinase-MB levels were significantly (P=0.046) lower in the off-pump group than in the on-pump group (17.1+/-16.7 IU/L versus 21.5+/-10.6 IU/L). The overall early graft patency rate with or without stenosis was the same (98%) in both groups, but the rate without stenosis was slightly worse in the off-pump group (93%) than in the on-pump group (96%) (P=0.093). The stenosis-free patency rate in the right coronary area was significantly (P=0.028) worse in the off-pump CABG group (90%) than in the on-pump group (99%).

CONCLUSIONS

Off-pump CABG with multiple arterial grafts was as safe as the conventional on-pump CABG, with similar completeness of revascularization and early graft patency.

Off-Pump Versus On-Pump Coronary Artery Bypass Grafting in Consecutive Patients: Decision-Making Algorithm and Outcomes

BACKGROUND

Debate continues between on-pump or off-pump approach for coronary artery bypass grafting (CABG). We used off-pump coronary artery bypass grafting (OPCAB) as a tool within a decision-making algorithm driven by the patient-related factors of coronary anatomy and comorbidity. Our analysis presents this decision algorithm and describes outcomes using this approach.

METHODS

From January 2000 to December 2003, 592 consecutive patients undergoing isolated CABG were assigned by one surgeon to a technique: on-pump CABG or OPCAB according to (1) anatomy and (2) predicted risk. Anatomic factors against OPCAB were target vessel size less than 1.25 mm, calcification, poor quality, intramyocardial location, and multiple stenoses. Given that OPCAB could be performed safely, patients in the moderate risk range, ie, those elderly with multiple comorbidities, were preferentially treated using OPCAB.

RESULTS

The OPCAB group had higher predicted 30-day mortality compared with the on-pump CABG group, consistent with the protocol's intent. However, morbidity and mortality were similar between on-pump CABG and OPCAB. The OPCAB patients received the same number of internal mammary artery grafts but fewer distal grafts. Mortality and observed to expected ratios were favorable for both groups and below those The Society of Thoracic Surgeons' predicted for OPCAB.

CONCLUSIONS

Matching surgical strategy to patient-related factors and needs resulted in excellent outcomes. Our data support the use of a protocol based on patient characteristics to drive the surgeon's choice between an on-pump CABG or OPCAB approach. As such, OPCAB can be viewed as a tool to be used by the surgeon developing a best practice in treating coronary artery disease.

Impact of off-pump coronary artery bypass surgery on postoperative bleeding: current best available evidence

Cardiopulmonary bypass (CPB) is a prerequisite for open-heart surgery, and is a procedure routinely used. CPB exposes blood to artificial surfaces, to mechanical trauma from the pump, to alterations in temperature, and to dilution with fluids, whole blood, plasma products, and drugs, and leads to the activation of platelets, coagulation, and fibrinolysis. Coagulopathy during cardiac surgery with CPB results in impairment in hemostasis and subsequently higher morbidity and mortality. Recent advances in surgical techniques and postoperative management have aimed at reducing postoperative morbidity and mortality. Off-pump coronary artery bypass (OPCAB) surgery is one such advance that attempts to avoid the deleterious effects of extracorporeal circulation by performing myocardial revascularization without CPB. Emerging evidence from several randomized controlled trials (RCTs) as well as large registries such as the Society of Thoracic Surgeons (STS) database suggests that OPCAB reduces the postoperative morbidity and mortality. This review article attempts to evaluate the current best available evidence from RCTs on the impact of OPCAB on postoperative bleeding and transfusion requirements.

Right Ventricular Function After Coronary Surgery with or Without Bypass

BACKGROUND AND OBJECTIVE

Myocardial protection during aortic clamp period may sometimes be inadequate, especially for the right. The aim of this study was to compare right ventricle function after cardiac surgery with or without bypass.

METHODS

Patients undergoing multivessel coronary surgery with proximal severe right coronary lesion were included in a prospective observational cohort study including 29 patients undergoing coronary surgery with or without bypass. All patients were monitored with a pulmonary artery catheter with continuous right ventricular function. Right ventricular ejection fraction was measured at the arrival in ICU, 1, 3, 6, and 18 hours later.

RESULTS

The number of grafts that was higher in the bypass group (4.0 +/- 1.3) than in the off-pump group (2.6 +/- 0.6, p = 0.001). In the on-pump group, the right ventricular ejection fraction significantly decreased from 32.9 +/- 2.8 at arrival in ICU to 26.1 +/- 2.4, 6 hours later whereas in the off-pump group, it did not significantly change (32.4 +/- 1.8 to 31.9 +/- 2.3). Meanwhile, at the same time intervals, CVP was significantly lower in the off-pump group.

CONCLUSIONS

In patients with severe right coronary stenosis, off-pump cardiac surgery seemed to provide better right ventricular protection.

Technology insight: randomized trials of off-pump versus on-pump coronary artery bypass surgery

Coronary artery bypass grafting has proven a remarkably effective treatment for occlusive coronary artery disease, with demonstrable impact on both symptoms and survival. As conducted traditionally, cardiopulmonary bypass is required, and a global myocardial ischemic insult imposed with aortic occlusion under the protection of cardioplegic arrest. Despite the remarkable success of this approach, concerns over the systemic effects of bypass, including neurologic sequelae as well as ischemic myocardial injury, have stimulated development of techniques and technology to perform coronary bypass 'off-pump'. This technique obviates the need for the bypass machine and imposes only brief regional ischemia during construction of each individual anastomosis. Despite enthusiastic support by a devoted cohort of surgeons, and a host of nonrandomized retrospective studies demonstrating an apparent benefit to the off-pump technique, the technique has not been universally adopted. How can there be such controversy over what appears to be a superior approach? In part, many surgeons are concerned that the greater technical difficulty of the technique will impact long-term results adversely. There is also uncertainty with regard to the actual advantage of off-pump coronary artery bypass over the tried-and-true methods. Surgeons recognize that the results of any surgical series are particularly subject to the influence of subtle selection biases. Accordingly, prospective randomized studies add particular value to the debate. It is the aim of this review to examine the evidence for off-pump coronary artery bypass critically, from a surgeon's perspective, with particular emphasis on knowledge derived from a representative selection of published prospective randomized studies.