Coronary Revascularization Without Cardiopulmonary Bypass Versus the Conventional Approach in High-Risk Patients

Coronary artery bypass surgery for acute coronary syndrome: A network meta-analysis of on-pump cardioplegic arrest, off-pump, and on-pump beating heart strategies

BACKGROUND

Coronary artery bypass grafting (CABG) in the setting of an acute coronary syndrome is a high-risk procedure, and the best strategy for myocardial revascularisation remains debated. This study compares the 30-day mortality benefit of on-pump CABG (ONCAB), off-pump CABG (OPCAB), and on-pump beating heart CABG (OnBHCAB) strategies.

METHODS

A systematic search of three electronic databases was conducted for studies comparing ONCAB with OPCAB or OnBHCAB in patients with acute coronary syndrome (ACS). The primary outcome, 30-day mortality, was compared using a Bayesian hierarchical network meta-analysis (NMA). A random effects consistency model was applied, and direct and indirect comparisons were made to determine the relative effectiveness of each strategy on postoperative outcomes.

RESULTS

One randomised controlled trial and eighteen observational studies fulfilling the inclusion criteria were identified. A total of 4320, 5559, and 1962 patients underwent ONCAB, OPCAB, and OnBHCAB respectively. NMA showed that OPCAB had the highest probability of ranking as the most effective treatment in terms of 30-day mortality (odds ratio [OR], 0.50; 95% credible interval [CrI], 0.23-1.00), followed by OnBHCAB (OR, 0.62; 95% CrI, 0.20-1.57), however the 95% CrI crossed or included unity. A subgroup NMA of nine studies assessing only acute myocardial infarction (AMI) patients demonstrated a 72% reduction in likelihood of 30-day mortality after OPCAB (CrI, 0.07-0.83). No significant increase in rate of stroke, renal dysfunction or length of intensive care unit stay was found for either strategy.

CONCLUSIONS

Although no single best surgical revascularisation approach in ACS patients was identified, the significant mortality benefit with OPCAB seen with AMI suggests high acuity patients may benefit most from avoiding further myocardial injury associated with cardiopulmonary bypass and cardioplegic arrest.

Use of the Purified Poloxamer 407 for Temporary Coronary Occlusion in Off-Pump CABG Does Not Cause Myocardial Injury

Objective

The new poloxamer 407 (LeGoo), a thermoreversible gel, previously showed efficiency in temporarily occluding coronary arteries and preserving endothelial function. However, its long-term effect on the myocardium after dissolution in bloodstream is uncertain.

Methods

Two groups of pigs (12 total) were compared after being submitted to a 10-minute coronary occlusion either with silastic loops (snare group) or with poloxamer 407 injection (P407 group). Reflow was procured by snare removal or P407 dissolution with topical cooling. Animals were kept alive for 3 days with creatine kinase-MB and troponin T (TnT) plasmatic measurement at 3 hours and 3 days after surgery, when they were killed for myocardial histopathologic study.

Results

Each animal survived during the study. Baseline plasmatic levels of cardiac enzymes were similar between both groups. No variation in creatine kinase-MB level throughout the study was seen in either group. A significant rise in TnT from baseline was noted 3 hours after reperfusion in both groups, with a peak level significantly lower in the P407 group (P < 0.05). TnT plasmatic levels returned to baseline level in both groups on the day the animals were killed (3 days). Histopathologic examinations of the stained myocardial samples showed no evidence of myocardial infarction either in the snare group or in the P407 group.

Conclusions

Poloxamer 407 does not cause myocardial damage after elimination in the bloodstream. The safety of this hemostatic device is now established, and application for FDA approval for human clinical studies is under way.

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.

The Effects of Diabetes Mellitus in Patients Undergoing Off-Pump Coronary Artery Bypass Grafting

Objective. To investigate the effects of diabetes mellitus (DM) in patients undergoing off-pump coronary artery bypass grafting (OPCAB). Method. A total of 728 patients with DM and 1380 patients without DM who underwent OPCAB treatment from March 2012 to April 2015 were reviewed. The effects of DM on intraoperative variables and postoperative complications were determined using propensity score analysis. Results. Two well-matched subgroups were selected using propensity score analysis (DM = 728, no-DM = 728) to compare the perioperative outcome. The duration of the ICU stay, in hours (55.2 ± 53.0 versus 49.29 ± 51.30, P < 0.05), postoperative new-onset atrial fibrillation (20.9% versus 14.97%, P < 0.05), and postoperative infection (9.2% versus 4.67%, P < 0.05) were greater in DM patients, as indicated by univariate analysis. Conclusion. OPCAB was found to be effective in DM patients, but postoperative infection and postoperative new-onset atrial fibrillation were found to be more likely to occur in DM patients than in other patients. DM was found to be a powerful risk factor for postoperative infection and postoperative new-onset atrial fibrillation.

Short-term clinical outcomes after hybrid coronary revascularization versus off-pump coronary artery bypass for the treatment of multivessel or left main coronary artery disease: a meta-analysis

Background

Hybrid coronary revascularization (HCR) and off-pump coronary artery bypass grafting (OPCABG) are both feasible, less invasive techniques for coronary revascularization. Although both techniques utilize the left internal mammary artery to left anterior descending artery graft, HCR uses drug-eluting stents instead of saphenous vein bypass. It remains unclear whether HCR is equal to, better or worse than OPCABG.

Methods and results

A meta-analysis was carried out using a random-effects model. Seven observational studies were included. There was no significant difference either in in-hospital mortality [relative risk (RR) 0.57, 95% confidence interval (CI) 0.13–2.59, P=0.47] or in the MACCE rate (RR 0.63, 95% CI 0.24–1.64, P=0.34) between the HCR group and the OPCABG group. A significant difference was observed between the two groups in the length of hospitalization (RR 0.55, 95% CI 0.13–0.97, P=0.01), length of ICU stay (RR 0.45, 95% CI 0.10–0.80, P<0.05), intubation time (RR 0.48, 95% CI 0.13–0.84, P<0.01), need for red blood transfusion (RR 0.67, 95% CI 0.56–0.82, P<0.001), and total in-hospital costs (RR 0.90, 95% CI 0.39–1.42, P<0.01).

Conclusion

Compared with OPCABG, HCR did not improve early survival but decreased the length of hospitalization, length of ICU stay, intubation time, and need for red blood transfusion, and increased total in-hospitalcosts.

Nonthyroidal illness syndrome in off-pump coronary artery bypass surger

OBJECTIVE

It is well known that coronary artery bypass grafting (CABG) is often the cause of non-thyroidal illness syndrome (NTIS). Non-thyroidal illness syndrome (NTIS) is a state characterized by low levels of tri-iodo-thyronine (T3) and high levels of reverse T3 (rT3), with normal or low levels of thyroxin (T4) and normal, low-normal, or low levels of thyroid-stimulating hormone (TSH). Today, there are two main techniques of CABG: CABG with the use of cardiopulmonary bypass (on-pump coronary artery bypass - ONCAB) and CABG without the use of cardiopulmonary bypass (off-pump coronary artery bypass OPCAB), or 'beating-heart surgery.' The OPCAB technique is considered to be less invasive. We prospectively investigated the influence of these surgical techniques on the occurrence of NTIS.

METHODS

Serum levels of free fractions of thyroid hormones (FT3 and FT4) and TSH were analyzed in 70 consecutive patients subjected to CABG surgery, using the ONCAB technique in 36 patients and OPCAB technique in 34 patients. The measurements of hormone levels were performed prior to surgery and 12 hours and 14 days after surgery.

RESULTS

The basic, the early, and the late postoperative serum levels of FT3 (p=0.458, p=0.632, p=0.869, respectively), FT4 (p=0.664, p=0.301, p=0.417, respectively), and TSH (p=0.249, p=0.058, p=0.324, respectively) were similar in both groups. The levels of FT3 and TSH were significantly lower 12 hours after surgery (p<0.0001, p<0.0001, respectively), and the FT4 levels rose at the same time (p<0.0001). The third measurement showed the return of all investigated parameters back to physiological levels, although they were still not precisely within the initial values.

CONCLUSION

NTIS occurs significantly in patients subjected to CABG. Although the OPCAB technique is considered to be less invasive, its impact on the occurrence of NTIS does not differ significantly from the ONCAB technique.

Early outcome of off-pump versus on-pump coronary revascularization

Introduction

The use of coronary artery bypass surgery (CABG) with cardiopulmonary bypass (CPB) or without CPB technique (off-pump) can be associated with different mortality and morbidity and their outcomes remain uncertain. The goal of this study was to evaluate the early outcome of on-pump versus off-pump CABG.

Methods

We conducted a retrospective database review of 13866 patients (13560 patients undergoing on-pump CABG and 306 patients undergoing off-pump CABG) at Tehran Heart Center between January 2002 and January 2007. We compared preoperative, operative, and postoperative characteristics between them.

Results

In-hospital mortality in the on-pump group was 0.8% compared to 0.7% in the off-pump group (P=0.999) and in-hospital morbidity was 11.7% and 6.5%, respectively (OR: 1.533, 95%CI: 0.902-2.605, P=0.114). Postoperative atrial fibrillation was more prevalent in on-pump versus off-pump surgery (6.0% vs 3.0%, P=0.028), however there were no statistical significant differences in other postoperative complications with regard to cardiac arrest (P=0.733), prolonged ventilation (P=0.363), brain stroke (P=0.999), renal failure (P=0.525), and postoperative bleeding (P=0.999). The mean length of stay in hospital (P=0.156) and in ICU (P=0.498) was also similar between the two groups.

Conclusion

The results from an Iranian population-based study showed similar early mortality and morbidity of off-pump CABG in comparison to on-pump surgery.

Comparison between normothermic and mild hypothermic cardiopulmonary bypass in myocardial revascularization of patients with left ventricular dysfunction

AIMS

The aim of this study was to investigate whether normothermic bypass is superior to mild hypothermia in patients with poor left ventricular function. This was achieved by studying defibrillation rates, postoperative requirements of cardiac pacing or other morbidity issues and mortality in patients with left ventricular dysfunction operated upon for elective coronary revascularization.

METHODS

Data were collected retrospectively from 252 consecutive patients with left ventricular dysfunction (ejection fraction ≤35%) undergoing coronary revascularization between January 2005 and January 2011. Patients operated upon under mild hypothermia (32 ºC) were placed in Group 1 and under normothermia (≥35 ºC) were placed in Group 2. Comorbidities and postoperative complications were recorded.

RESULTS

There were 128 patients in Group 1 and 124 patients in Group 2. Plasma concentrations of CK-MB and troponin T peaked at 6 hours postoperatively, with no significant difference between the groups. Despite longer aortic cross-clamp time and total bypass time in Group 2, significantly less defibrillation requirement rates after aortic declamping was observed. Hospital mortality occured in 16 patients; 8 patients in each group.

CONCLUSIONS

Normothermia enables less requirement for defibrillation after aortic declamping and postoperative cardiac pacing in patients with left ventricular dysfunction, which may be interpreted as better myocardial protection under normothermic bypass. However, maintaining normothermia had no effect on postoperative stroke, postoperative atrial fibrillation, renal failure development and mortality.

Off-pump coronary surgery may reduce stroke, respiratory failure, and mortality in octogenarians

BACKGROUND

Octogenarians are a challenging group of patients referred for cardiac surgery. The aim of this study is to assess early outcomes of coronary artery bypass grafting (CABG) performed in the elderly population.

METHODS

We performed a meta-analysis of all published observational studies comparing early results of conventional CABG surgery and off-pump CABG surgery in patients aged 80 years or older. The outcomes of interest were mortality, stroke, respiratory failure, renal failure, incidence of support with intraaortic balloon pump, and incidence of postoperative atrial fibrillation. The random effects model was used.

RESULTS

Fourteen studies were analyzed. The total number of included subjects was 4,991, of whom 3,113 underwent conventional CABG surgery (62.4%), and 1,878 (37.6%) underwent off-pump CABG surgery. The rates of mortality, stroke, and respiratory failure were significantly higher in the conventional CABG surgery group.

CONCLUSIONS

These results confirm that off-pump CABG surgery remains a valuable option of surgical myocardial revascularization, and may optimize the outcome in senior patients.

On-pump versus off-pump coronary artery bypass surgery in high-risk patients: operative results of a prospective randomized trial (on-off study)

OBJECTIVE

To analyze the risk reduction of cardiopulmonary bypass complications between on-pump and off-pump coronary artery bypass grafting in high-risk patients.

METHODS

This multicenter, prospective, randomized, parallel trial enrolled patients for elective or urgent isolated coronary artery bypass grafting with an additive European System for Cardiac Operative Risk Evaluation of 6 or more. The patients in cardiogenic shock were excluded. The composite primary end point included operative mortality, myocardial infarction, stroke, renal failure, reoperation for bleeding and adult respiratory distress syndrome within 30 days after surgery. The total sample size was 693 patients, according to a scheduled interim analysis at 400 patients enrolled (α-spending = 0.029, Pocock method).

RESULTS

A total of 411 patients were included in the interim analysis. Randomization assigned 203 patients to on-pump and 208 patients to off-pump treatment. Of the 411 patients, 24 crossed over; thus, 195 patients were actually treated on-pump and 216 off-pump. According to the intention to treat analysis, the rate of the composite primary end point was significantly lower (unadjusted P = .009, adjusted P = .010) in the off-pump group (5.8% vs 13.3%). The risk of experiencing the primary end point was significantly greater for the on-pump group (unadjusted odds ratio, 2.51; 95% confidence interval, 1.23-5.10; P = .011; adjusted odds ratio, 3.07; 95% confidence interval, 1.32-7.14; P = .009).

CONCLUSIONS

Off-pump coronary artery bypass grafting reduces early mortality and morbidity in high-risk patients.

Safe introduction and quality control of new methods in coronary surgery

Introduction:

The first part of the paper analyses off pump coronary bypass surgery (OPCAB), which is compared with traditional on-pump procedures (ONCAB). Furthermore ,the paper evaluates the use of a new automatic device for performance of the proximal anastomosis and finally the effect of intracoronary shunt on myocardial ischemia during OPCAB. The main goal of the paper is to demonstrate the importance of careful clinical studies during introduction of the new techniques in cardiac surgery.

Methods:

Statistical analysis was performed on a large clinical database from Buffalo, NY, USA comparing OPCAB and ONCAB. Subsequently, a sequential controlled clinical study compared patients operated with a new automatic connector device to patients operated with classic suture technique. Finally a randomized study was performed to evaluate the effect of the use of an intracoronary shunt during construction of distal anastomosis.

Results:

The studies from Buffalo demonstrated reduced complications rates in high risk patients when OPCAB techniques were used. The use of connector devices in saphenous venous anastomosis was clearly inferior to standard technique. Intracoronary shunt was found to be beneficial by preventing ischemia.

Discussion:

Numerous studies have studied the results of OPCAB vs ONCAB and although results are variable it seems that OPCAB is advantageous in high risk patients, while in low risk patients there are much less if any benefit. The results of the studies of connector devices caused the product to be taken off the market. The value of shunt in OPCAB was clearly demonstrated by the randomized studies.

Conclusion:

The investigations presented in this paper clearly demonstrates the importance of well-designed studies when new surgical methods are introduced. In the present period of rapid technological development, carefully controlled, un-biased clinical trials are crucial to preserve patient safety and avoid unjustified societal cost.

Impact of incomplete surgical revascularization on survival

Complete revascularization is considered superior to incomplete revascularization (IR), with better long-term survival and a lower rate of reintervention. However, it has yet to be established whether this difference is due directly to IR as a surgical strategy or whether this approach is merely a marker of more severe coronary disease and more rapid progression. We believe that IR is a prognostic marker for a more complex coronary pathology, and adverse effects are probably due to the preoperative condition of the patient. In fact, although IR may negatively affect long-term outcomes, it may be, when wisely chosen, the ideal treatment strategy in selected high-risk patients. IR can derive from a surgical strategy of target vessel revascularization, where the impact of surgery is minimized to reduce perioperative mortality and morbidity, aiming to achieve the best feasible safe revascularization.

Off-pump surgery is not a contraindication for patients with a severely decreased ejection fraction

BACKGROUND

A severely impaired left ventricular ejection fraction (EF) (30%) increases the risk of surgical myocardial revascularization. We evaluated the safety and feasibility of off-pump coronary artery bypass (OPCAB) surgery in patients with a severely decreased EF.

METHODS

We compared 79 patients with an EF ≤30% (group A) with 863 patients with an EF >30% (group B) who underwent myocardial revascularization between 2003 and 2008. The relationship between EF and outcome after OPCAB was assessed by univariate and logistic regression analyses. A composite end point was constructed from 30-day mortality, renal failure, length of stay in the intensive care unit (ICU) >2 days, neurologic complications, and use of an intra-aortic balloon pump (IABP). Additionally, the completeness of revascularization was assessed.

RESULTS

The mortality rates for groups A and B were comparable (1.3% and 2.0%, respectively; P = .55), and the 2 groups did not differ with regard to serious postoperative complications, such as stroke (2.5% versus 1.4% for groups A and B, respectively; P = .42), peripheral neurologic complications (2.5% versus 0.7%, P = .14), renal failure (0% versus 1.1%, P = 1.00), use of an IABP (1.3% versus 0.8%, P = .50), ICU length of stay >2 days (17.7% versus 19.6%, P = .77). Similarly, groups A and B did not differ with regard to ventilation time (11.2 ± 12.7 hours versus 12.4 ± 15.5 hours, P = .82), indicating similar postoperative courses for the 2 groups of patients. In contrast, the composite end point occurred significantly more frequently in group A (43.0% versus 29.7%, P = .02), a result driven by the increased rate of rethoracotomy for bleeding in that group (11.4% versus 2.9%, P = .001). The 2 groups were similar with respect to the total number of grafts used per patient (3.82 ± 0.89 versus 3.63 ± 1.01, P = .10) and the completeness of revascularization (94% versus 93%, P = .49).

CONCLUSION

A standardized OPCAB approach is safe for patients with a severely decreased EF, and its use does not come at the cost of less complete revascularization.

The influence of a low ejection fraction on long-term survival in systematic off-pump coronary artery bypass surgery

OBJECTIVE

Poor left-ventricular ejection fraction (EF) is a recognized operative and long-term risk factor in coronary artery bypass surgery. Over the past decade, off-pump coronary artery bypass surgery has emerged as a new strategy to address myocardial revascularization in poor left-ventricular EF patients, but few reports have documented long-term results. The aim of this study was to investigate long-term clinical results in off-pump coronary artery bypass patients with ≤ 35% left-ventricular EF.

METHODS

From September 1996 to May 2006, 1250 patients underwent off-pump coronary artery bypass revascularization, and were prospectively followed-up at the Montreal Heart Institute. Among them, 137 patients (pts) had a preoperative left-ventricular EF ≤ 35%. Follow-up was completed in 97% of patients.

RESULTS

Mean follow-up was 66 ± 34 months. Rate of grafts per pts was comparable in both groups. Overall 30-day mortality was 1.7% (1.5% EF >35% pts vs 2.9% in EF ≤ 35% pts; p = 0.19). Ten-year survival was lower in poor EF patients (44 ± 7% vs 76 ± 2%), and remained significant even after adjusting for risk factors (p = 0.04). Freedom from cardiac death for both groups was also significantly reduced in poor EF patients (p = 0.008). After adjustment, freedom from the combined end point of cardiac or sudden death, myocardial infarction, repeat coronary revascularization, unstable angina, and cardiac failure was comparable in both groups (p = 0.5).

CONCLUSIONS

Off-pump coronary artery bypass surgery can be performed adequately and safely in poor EF patients. However, overall and cardiac survival was decreased in this subset of patients with a comparable freedom from major cardiac adverse related events.

Long-term influence of mild or moderate ischemic mitral regurgitation after off-pump coronary artery bypass surgery

BACKGROUND

The issue of mild to moderate ischemic mitral regurgitation (IMR) is controversial after conventional surgery, and has not been specifically studied after off-pump coronary artery bypass graft (OPCAB) surgery.

OBJECTIVE

To review the influence of mild or moderate IMR on longterm survival and recurrent cardiac events after OPCAB surgery.

METHODS

A total of 1000 consecutive and systematic OPCAB patients who underwent operations between September 1996 and March 2004 were prospectively followed. Sixty-seven patients (6.7%) had mild to moderate IMR at the time of surgery. Operative mortality, actuarial survival and major adverse cardiac event-free survival were studied to assess the effect of IMR.

RESULTS

The mean (+/- SD) follow-up period was 66+/-22 months and was completed in 97% of the cohort. IMR patients were older (P<0.001), and had lower ejection fractions (P<0.001) and more comorbidities. More female patients presented with IMR (P=0.002). Operative mortality (P=0.25) and prevalence of perioperative myocardial infarction (P=0.25) were comparable for both groups. Eight-year survival was decreased in IMR patients (P<0.001), but after adjusting for risk factors in the Cox regression model, mild to moderate IMR was not found to be a significant risk factor of long-term mortality (P=0.42). Major adverse cardiac event-free survival at eight years was significantly lower in IMR patients (P<0.001) and, more specifically, in patients with 2+ IMR. After adjusting for risk factors, IMR remained a significant cause of poor outcome (hazard ratio 2.09), especially for recurrent congestive heart failure and myocardial infarction.

CONCLUSIONS

OPCAB patients with preoperative mild or moderate IMR had a higher prevalence of preoperative risk factors than those without IMR. They had comparable perioperative mortality and morbidity but, over the long term, were found to be at risk for recurrent cardiac events.

No major differences in 30-day outcomes in high-risk patients randomized to off-pump versus on-pump coronary bypass surgery: the best bypass surgery trial

BACKGROUND

Off-pump coronary artery bypass grafting compared with coronary revascularization with cardiopulmonary bypass seems safe and results in about the same outcome in low-risk patients. Observational studies indicate that off-pump surgery may provide more benefit in high-risk patients. Our objective was to compare 30-day outcomes in high-risk patients randomized to coronary artery bypass grafting without or with cardiopulmonary bypass.

METHODS AND RESULTS

We randomly assigned 341 patients with a EuroSCORE > or = 5 and 3-vessel coronary disease to undergo coronary artery bypass grafting without or with cardiopulmonary bypass. Patients were followed through the Danish National Patient Registry. The primary outcome was a composite of adverse cardiac and cerebrovascular events (ie, all-cause mortality, acute myocardial infarction, cardiac arrest with successful resuscitation, low cardiac output syndrome/cardiogenic shock, stroke, and coronary reintervention). An independent adjudication committee blinded to treatment allocation assessed the outcomes. Baseline characteristics were well balanced between groups. The mean number of grafts per patient did not differ significantly between groups (3.22 in off-pump group and 3.34 in on-pump group; P=0.11). Fewer grafts were performed to the lateral part of the left ventricle territory during off-pump surgery (0.97 versus 1.14 after on-pump surgery; P=0.01). No significant differences in the composite primary outcome (15% versus 17%; P=0.48) or the individual components were found at 30-day follow-up.

CONCLUSIONS

Both off- and on-pump coronary artery bypass grafting can be performed in high-risk patients with low short-term complications. CLINICAL TRIAL REGISTRATION- clinicaltrials.gov. Identifier: NCT00120991.

Current practice and outcomes of off-pump multivessel coronary artery bypass

Outcomes of off-pump multivessel coronary artery bypass were compared with those of the on-pump procedure. From July 2001 to June 2006, 3,637 patients with multivessel coronary disease underwent off-pump coronary artery bypass, and 3,586 patients had on-pump coronary artery bypass in our center. The rates of operative mortality, permanent stroke, renal failure and perioperative myocardial infarction were significantly lower in the off-pump group, and these patients required fewer blood transfusions, shorter durations of ventilatory support, and shorter hospital stays. However, the patients who underwent on-pump coronary artery bypass were considered more high-risk and tended to have more complex procedures.

Evaluation of preoperative intra-aortic balloon pump in coronary patients with severe left ventricular dysfunction undergoing OPCAB surgery: early and mid-term outcomes

Background

The purpose of the present study was to evaluate the safety and the cost-effectiveness of using preoperative IABP as support compared with postoperative IABP treatment in coronary patients with severe left ventricular dysfunction (SLVD) who is undergoing off-pump coronary artery bypass surgery (OPCAB), including early outcomes, hospital mortality and morbidity, and mid-term follow-up outcomes.

Methods

Between March 2000 and December 2008, we prospectively and randomly studied the insertion of preoperative IABP in 115 (7.4%) and postoperative IABP in 106 (6.8%) of the 1560 consecutive patients. Group A is preoperative IABP therapy. Group B is postoperative IABP therapy.

Results

There was no significant difference in the number of grafts used between the two groups. Completeness of revascularization did not differ between the two groups. The statistically significant difference was hospital mortality (2.6% in group A vs. 3.8% in group B) (p < 0.05). And there was significant reduction in postoperative low cardiac output, malignant arrhythmia, acute renal failure and length of stay in ICU in group A, compared with group B (p < 0.05). In the two groups, six-, 12-, 24- and 48-month survival rates were similar. In the study the degree of improvement in angina and quality of life did not differ significantly between the two groups.

Conclusion

The use of preoperative IABP in SLVD patients undergoing OPCAB is of safety and effectiveness. The combined use of preoperative IABP and OPCAB allows complete revascularization in SLVD patients with an important reduction in operative mortality and excellent mid-term results.

Off-pump coronary artery bypass grafting improves in-hospital mortality in patients with dialysis-dependent renal failure

OBJECTIVE

Patients with chronic dialysis-dependent end-stage renal disease are increasingly referred for coronary artery bypass grafting (CABG) and their early outcome is less favorable. Off-pump CABG (OPCAB) has achieved encouraging results in high-risk patients. Therefore, we designed this retrospective study to test the hypothesis that OPCAB reduced surgical risks in dialysis patients.

METHODS

From January 2000 to December 2005, 294 dialysis-dependent patients received isolated CABG at the Washington Hospital Center. Among them, 168 underwent OPCAB (off-pump group), and 126, CABG with cardiopulmonary bypass (CPB) (on-pump group). The in-hospital outcomes were analyzed.

RESULTS

The two groups were comparable in terms of preoperative characteristics. The Parsonnet's Bedside Score of the off-pump group was similar to that of the on-pump group (32.0 vs. 32.0, P=.57). The in-hospital mortality of the off-pump group was significantly lower than that of the on-pump group (5.4% vs. 11.9%, P=.04). Although the percentage of patients who received transfusions was similar, the on-pump group received more total transfusions. Logistic regression analysis revealed that use of CPB independently predicted in-hospital mortality [odds ratio (OR), 5.0; 95% confidence interval, 1.78-13.85; P<.01] and perioperative myocardial infarction (MI; OR, 5.1; 95% confidence interval, 1.18-22.40; P=.03). No significant difference in long-term survival at 4 years was absorbed between the two groups of hospital survivors.

CONCLUSIONS

Our data suggest that OPCAB is a safe alternative to on-pump CABG in dialysis patients. Avoiding CPB resulted in less perioperative blood utilization, MI, and hospital mortality.

[Coronary artery bypass grafting in conscious patients: a procedure with a perspective?]

Patients undergoing coronary artery bypass grafting increasingly show severe co-morbidities, which can negatively affect the outcome. Recent developments in cardiac surgery have therefore focused on minimizing the invasiveness of the procedure by revascularization on the beating heart without cardiopulmonary bypass, and by reducing surgical trauma using smaller surgical incisions. Progress in minimally invasive cardiac surgery has led to minimally invasive anesthesia, i.e. using high thoracic epidural anesthesia as the sole technique in the conscious patient (awake coronary artery bypass grafting, ACAB). Published data on ACAB procedures in smaller cohorts have demonstrated that the procedure is safe. Significant complications occurred in 7.1% of patients. A particular cause of concern during ACAB surgery is the development of spinal epidural hematoma the risk of which has been estimated to be as high as 1:1,000. A thorough risk-benefit analysis has therefore to be made. Currently, ACAB surgery remains limited to few specialized centers and highly selected patients.

Influence of diabetes mellitus on long-term survival in systematic off-pump coronary artery bypass surgery

BACKGROUND

Diabetic patients generally present a more diffuse and calcified coronary artery disease than nondiabetic patients that can affect long-term outcome especially if an off-pump coronary artery bybass graft (OPCABG) technique is used. The aim of this study was to compare long-term results of OPCABG surgery for diabetic and nondiabetic patients.

METHODS

This is a retrospective analysis of prospectively gathered data over a 10-year period of 1,000 consecutive and systematic OPCABG patients operated on between September 1996 and April 2004. Average follow-up period was 66 +/- 28 months and was 97% complete. Overall survival as well as occurrence of major adverse cardiac events in diabetic and nondiabetic patients were specifically studied.

RESULTS

In all, 278 diabetic patients and 722 nondiabetic patients were treated. There was no difference in 30-day mortality between the two groups (p = 0.70). Diabetic patients had more postoperative acute renal insufficiency (p = 0.01) and infections (sepsis; p = 0.002), and deep sternal infections (p = 0.04) Ten-year survival (p = 0.006) and survival free of major adverse cardiac events (p = 0.02) was decreased in the diabetic group. Age (hazard ratio [HR] = 1.06), peripheral vascular disease (HR = 1.72), carotid disease (HR = 1.53), congestive heart failure (HR = 1.51), incomplete revascularization (HR = 2.37), chronic renal insufficiency (HR = 1.93), left ventricular ejection fraction (HR = 0.13), and a lesser use of multiple internal thoracic artery grafts (HR = 0.67), but not diabetes mellitus (p = 0.13) were significant determinants of long-term mortality. Similarly, peripheral vascular disease (HR = 1.92), chronic renal insufficiency (HR = 2.36), emergent operation (HR = 1.71), chronic obstructive pulmonary disease (HR = 1.76), previous percutaneous coronary intervention (HR = 1.66), left ventricular ejection fraction (HR = 0.26), ischemic mitral regurgitation (HR = 1.83), and a lesser use of multiple internal thoracic artery grafts (HR = 0.72) were determinants of decreased survival free of major adverse cardiac events but not diabetes (p = 0.2). Breaking down the major adverse cardiac events, diabetes was found an independent predictive factor of recurrent myocardial infarction (HR = 1.85) and a borderline cause of readmission for congestive heart failure (p = 0.06). Need for new revascularization was comparable for both population (p = 0.37).

CONCLUSIONS

In our series of OPCABG surgery patients, diabetic patients had a comparative operative mortality and perioperative myocardial infarction rate as nondiabetic patients. However, they had an increased prevalence of postoperative acute renal insufficiency and infections. They also had a worse outcome than nondiabetic patients, but that was mainly due to a higher prevalence of preoperative comorbidities and a lesser use of multiple internal thoracic artery grafts. However, diabetes itself was a potential risk factor for long-term occurrence of myocardial infarction and congestive heart failure.

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.

Reduced Mortality in High-Risk Coronary Patients Operated Off Pump With Preoperative Intraaortic Balloon Counterpulsation

BACKGROUND

Preoperative intraaortic balloon pump (IABP) counterpulsation has better outcomes compared with perioperative or postoperative insertion in critical patients, and off-pump surgical procedures have been advocated to reduce mortality in high-risk patients. However, some surgeons are reluctant to perform beating heart operations in specific patient subgroups, including those with unstable angina or patients with low ejection fraction, because of their possible perioperative hemodynamic instability.

METHODS

We evaluated combined beating heart procedures and preoperative IABP in selected high-risk patients and compared our results with the predictive European System for Cardiac Operative Risk Evaluation (EuroSCORE) model. Fifty-five high-risk patients with a mean logistic EuroSCORE of 24 were prospectively enrolled and then divided into emergency (group 1, n = 25) and nonemergency (group 2, n = 30) groups. IABP was inserted immediately before operation in group 1 and the day before the procedure in group 2.

RESULTS

Compared with the EuroSCORE predictive model, a dramatic decrease in mortality occurred in both groups. Group I predicted mortality was 36.8%, and observed was 20%; and group 2 predicted mortality was 15.2% and observed was 0%. No specific complications from the use of IABP were encountered. During mid-term (2 years) follow-up, no patient died from a cardiac cause or required percutaneous coronary intervention or subsequent reoperation due to incomplete revascularization.

CONCLUSIONS

The combined use of preoperative intraaortic counterpulsation and beating heart intervention allows complete revascularization in high-risk patients with a important reduction in operative mortality and excellent mid-term results.

Off-pump strategy in high-risk coronary artery bypass reoperations

OBJECTIVE

To determine the role of off-pump coronary artery bypass grafting in the treatment of patients with severe recurrent angina after coronary artery bypass grafting who are not suitable for percutaneous coronary intervention and are considered too high risk for conventional on-pump revascularization.

PATIENTS AND METHODS

All patients who needed single- or double-vessel revascularization at reoperation with a predicted operative mortality of 10% or higher between March 4, 1994, and December 31, 2002, were studied. Risk stratification was performed using both the Parsonnet risk scoring system and the European System for Cardiac Operative Risk Evaluation. Active follow-up by questionnaire investigated major adverse cardiac events.

RESULTS

This study consisted of 84 patients with a median age of 69 years (interquartile range, 62-75 years); 14 (17%) were female. All patients had class III/IV symptoms. Previous operations included multiple coronary artery bypass grafts (15 patients [18%]) and heart transplantation (1 patient [1%]). Internal thoracic artery graft from a previous operation was patent in 43 patients (51%). Perioperative hemodynamic support with inotropes (35%) and intra-aortic balloon pump (14%) or ventricular assist device (2%) was common. The surgical approach varied for each patient. One operative death (1%) occurred. Estimated survival at 5 and 7 years was 77% and 67%, respectively. Late major adverse cardiac events observed during follow-up were cardiac death (n=66), nonoperative reintervention (n=8), and nonfatal myocardial infarction (n=5).

CONCLUSION

Off-pump coronary artery bypass grafting can mitigate reoperative risk in patients with an estimated risk of 10% or higher who are undergoing single- or double-vessel revascularization with satisfactory long-term outcome.

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.

Intraoperative Transesophagial Echocardiography Modifies Strategy in Off-Pump Coronary Artery Bypass Grafting

BACKGROUND

Off-pump coronary artery bypass graft surgery (OPCAB) can improve operative morbidity and mortality in high risk patients. Intraoperative transesophageal echocardiography (ITEE) is being employed increasingly during cardiac surgery.

METHODS

Routine ITEE was performed in 744 OPCAB patients performed over a five year period. Mean patient age was 69.1 +/- 8.0 years. There were a high percentage of patients over 70 years (39%), diabetics (26%), poor left ventricular function (< or = 35%) (31%), recent myocardial infarction (24%), unstable angina (15%), and preoperative intraaortic balloon pump (5.6%); mean graft number was 3.4.

RESULTS

There was a major modification in intraoperative strategy in 117 patients (16%) and minor modification in 77 patients (10%) due to information available through the ITEE (total 26%). Graft revision was performed in 39 patients, graft construction was modified due to severe ascending aortic atherosclerosis in 31, and an intraoperative intraaortic balloon pump was placed due to previously underappreciated left ventricular dysfunction and new intraoperative left ventricular dysfunction in 37 patients. Ten patients were placed on cardiopulmonary bypass due to previously unknown intracardiac pathology (three atrial septal defect repairs and five valvular procedures, two others). Intracoronary shunts were placed due to new wall motion changes during anastomosis in 77 patients. There were two emergent conversions to cardiopulmonary bypass. There were no complications due to ITEE probe placement.

CONCLUSIONS

Intraoperative transesophageal echocardiography is a valuable adjunct and can result in a major change of surgical strategy in a significant number of patients when used routinely for OPCAB. It may also improve surgical outcome and add to the OPCAB benefits.

Coronary Endarterectomy on Beating Heart: Is It Worth Doing?

BACKGROUND

Management of patients with severely impaired left ventricular function (LVF) associated with diffusely atheromatous coronary artery disease is a real dilemma. Coronary revascularization can be done only after endarterectomy to facilitate anastomosis. The aim of the present work is to present our experience and see whether performing endarterectomy during off-pump bypass can be of any benefit.

PATIENTS AND METHODS

Five patients with a mean ejection fraction of 27 +/- 4.5 underwent coronary revascularization facilitated by endarterectomy using off-pump technique. There were three males and two females with a mean age of 64.4 +/- 7.4 years. All patients were in NYHA class III or IV. Close endarterectomy was done to left anterior descending artery (LAD), right coronary artery (RCA), and intermediate artery.

RESULTS

All patients survived the procedure. A total of seven closed endarterectomies were performed. Five of these were done on LAD and the other two were done on RCA and intermediate artery. Two patients (40%) received inotropic support. One patient had perioperative infarction (20%). Mean follow-up period was 14.2 months +/- 19.7 (range, 1 month to 48 months). All patients were free of angina according to Canadian Cardiovascular Society and were in class NYHA I or II except one, who was in class III. Postoperative catheterization showed that all bypasses to endarterectomized arteries were patent. Patency rate was 83.4%. The mean postoperative ejection fraction was 29.8 +/- 6.9, which was not significantly different from preoperative one (p= 0.12).

CONCLUSION

Performing endarterectomy on beating heart in patients with compromised left ventricle is not an easy task. But it can be done with difficulty. Although the procedure is associated with high incidence of infarction, our early results, follow-up clinical status, and graft patency justify its use among patients with compromised left ventricular function who were previously considered inoperable.

Long-term outcomes of the symmetry vein graft anastomosis device: a matched case-control analysis

BACKGROUND

The Symmetry Bypass Connector (St. Jude Medical) was developed to rapidly anastomose saphenous vein grafts to the aorta during coronary bypass surgery (CABG) without cross-clamping. Previous uncontrolled studies of this device observed vein graft closures at six months, possibly attributable to neointimal hyperplasia.

METHODS AND RESULTS

To assess the long-term clinical outcomes of the Symmetry device, we performed a retrospective matched case-control analysis of patients who underwent CABG at Duke Medical Center between January 1, 2002 and December 31, 2003. In 121 patients, at least one proximal anastomosis used a Symmetry device. Traditional suture methods were used in 178 control patients, matched by age group, gender, use of cardiopulmonary bypass, and Hannan perioperative risk score. One-year outcomes were compared using the log-rank test and Cox proportional hazards regression models. Major adverse events were more frequent among cases compared with controls. By unadjusted Kaplan-Meier analysis for the composite end point of death, nonfatal myocardial infarction, repeat cardiac catheterization, or repeat CABG, there was a trend towards increased events in the Symmetry device group (P=0.053). No significant differences were detected for stroke, all cause mortality, or the combined end point of death or nonfatal myocardial infarction.

CONCLUSIONS

Use of the Symmetry Bypass Connector was associated with increased risk for major adverse events at 1 year, suggestive of early graft closure. The potential reductions in operative stroke risk (from the elimination of aortic cross-clamping) must be weighed against the potential risk for later adverse events. These findings encourage close follow-up of patients who received this device.

Long-Term Results After Systematic Off-Pump Coronary Artery Bypass Graft Surgery in 1000 Consecutive Patients

Background— Off-pump coronary artery bypass surgery (OPCAB) is currently used as an alternative to conventional “on-pump” surgery, but there are very little data available on long-term follow-up. The aim of this study was to review our long-term experience with the use of systematic OPCAB.

Methods and Results— 1000 consecutive OPCAB surgeries were systematically performed between 1996 and 2004, representing 95% of all coronary revascularization during that same time frame, with a 97% complete follow-up. Average age of the patients was 64±10 years (778 men and 222 women). Seventy-three percent had triple-vessel disease. Operative 30-day mortality was 1.6%. Overall survival at 96 months was 74±3.5% and cardiac survival was 94±1.3%. By Cox regression analysis, age (odds ratio [OR], 1.07), congestive heart failure (CHF) (OR, 1.90), peripheral vascular disease (OR, 1.74), chronic renal insufficiency (OR, 2.04), previous myocardial infarction (MI) (OR, 1.60), and New York Heart Association functional class (OR, 1.60) were risk factors for long- term mortality. Survival free of any cardiac events (cardiac death, MI, unstable angina, heart failure, or reintervention) was 80±3.4%. Survival free of any type of reintervention alone was 90±3%. By Cox regression analysis, mitral regurgitation (OR, 2.3), peripheral vascular disease (OR, 2.1), and diffuse coronary disease (OR, 2.3) were significant predictors of recurrent cardiac events. Conversion to “on-pump” (OR, 14.3) was predictor of long-term need for repeat revascularization.

Conclusion— In this series, systematic OPCAB surgery was shown to be an acceptable alternative to conventional “on-pump” coronary artery bypass graft for the treatment of coronary artery disease.

Clinical Outcomes of Low-Risk Patients Undergoing Beating-Heart Surgery With or Without Pulmonary Artery Catheterization

OBJECTIVE

For patients who undergo off-pump coronary artery bypass (OPCAB) surgery, pulmonary artery catheterization (PAC) has been proposed as a useful intraoperative monitoring tool. This study was designed to determine if the choice of PAC versus central venous pressure monitoring (CVP) had any effect on outcome after OPCAB. This study compared these 2 methods of hemodynamic monitoring in low-risk patients undergoing beating-heart surgery via a median sternotomy and evaluated their effect on morbidity and in-hospital mortality.

DESIGN

Retrospective database and medical record review.

SETTING

Tertiary care teaching hospital.

PARTICIPANTS

Low-risk patients who had coronary revascularization via a median sternotomy on the beating heart.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

A population of 2,414 low-risk patients who had beating-heart coronary revascularization between January 2000 and December 2003 was reviewed. Most patients (1,671 or 69.2%) received a PAC, whereas 743 (30.8%) had CVP monitoring. Risk-adjusted logistic regression analyses were performed to investigate the effect of each technique on clinical outcomes. The groups were comparable in both baseline characteristics and Parsonett's mortality risk (1.5 +/- 0.9, p = 0.58). Univariate analysis failed to show a difference in operative mortality (p = 0.76), on-pump conversion rate for completion of aortocoronary bypasses (p = 0.82), postoperative low cardiac output (p = 0.10), or prolonged inotropic agent use (p = 0.22). Similarly, in the multivariate analysis, both groups had a similar rate of conversion to an on-pump procedure for completion of coronary artery grafting (p = 0.91), intraoperative intra-aortic balloon pump use (p = 0.69), low cardiac output state (p = 0.16), or in-hospital mortality (p = 0.51).

CONCLUSIONS

This single-institution, retrospective study suggests that in low-risk patients undergoing beating-heart surgery, CVP monitoring may be sufficient.

[Should we avoid cardiopulmonary bypass with diabetic patients?]

In the peri-operative and post-operative course of coronary bypass operations, the diabetic patient is susceptible to complications that cause morbidity and mortality. Morbidity might best be conceptualized as the cumulative effect of the diabetic patient chronically at risk and a variety of surgically related insults, including surgical stress, anaesthesia, hypo- and hypertension, anaemia, dysrhythmias, de- or hyperhydration and cardiopulmonary bypass (CPB) that exceed the compensatory capacities of the patient. Because all these factors for adverse outcome coexist, it becomes difficult to determine which ones are most important. However, it is reasonable that, in the presence of generalized atherosclerosis affecting the aorta ascendens, carotids and the cerebral arteries, the interaction of CPB-associated embolization, hypoperfusion and inflammation may cause neurologic morbidity. Many physiologic alterations (such as non-pulsatile perfusion and hemodilution) occur during CPB and may worsen renal dysfunction in patients with diabetic nephropathy. Pulmonary dysfunctions, associated with diabetic microangiopathy, could be unmasked by atelectasis, capillary leak and other pathophysiological conditions developing after the use of extracorporeal circulation. Actually, there is evidence that with the avoidance of CBP and the use of adequate OPCAB (Off Pump Coronary Artery Bypass) techniques, by experienced teams, the incidences of neurological, renal and pulmonary complications decrease, in high-risk patients, e. g. diabetics, as well as in unselected cohorts. Because it is not possible to identify confidently those patients who are at risk for CPB-associated complications, we use a strategy where all CABG (Coronary Artery Bypass Grafting) are performed in OPCAB technique. The total OPCAB approach will in addition ascertain the development of organizational OPCAB routines and expertise. The process of re-engineering the unit towards total OPCAB needs systematic training and re-training of cardiac surgeons by surgeons, experienced in both, OPCAB surgery and knowledge transfer, according to the principles of continuing medical education (CME). Thus, the chances of the OPCAB technique improving the outcome of diabetic patients can be fully realized.

Stroke and Encephalopathy After Cardiac Surgery

Background and Purpose— As a result of advances in surgical, anesthetic, and medical management, cardiac surgery can now be performed on older, sicker patients, some of whom have had prior cardiac interventions. As surgical mortality has declined in recent years, attention has focused on the complications of stroke and encephalopathy after cardiac surgery.

Summary of Review— Patients with preexisting cerebrovascular disease are at increased risk for these untoward neurological outcomes, which are associated with longer lengths of hospital stay, higher costs, and greater mortality. The mechanisms underlying these neurological events may include microemboli and hypoperfusion during surgery, and postoperative atrial fibrillation. Predictive models, based on information available before surgery, allow identification of these “high risk” patients.

Conclusion— Establishing the degree of functionally significant vascular disease of the brain before surgery should be an essential part of the preoperative evaluation, particularly when modifications in surgical technique or novel neuroprotective agents are being evaluated.

Myocardial Revascularization in Patients with Low Ejection Fraction <=35%: Effect of Pump Technique on Early Morbidity and Mortality

BACKGROUND AND AIM

Left ventricular dysfunction is an important predictor of in-hospital mortality. Surgical risk among these patients remains high. The present study is conducted to evaluate the difference in early morbidity and mortality among patients with compromised left ventricular function (LVF) after myocardial revascularization using either off-pump or on-pump coronary artery bypass graft.

METHODS

Between April 2000 and April 2004, 150 patients with ejection fraction (EF) < or =35% underwent isolated coronary artery bypass grafting. Eighty-four patients underwent conventional bypass (mean EF 30.1%+/- 4.2) and 66 patients had off-pump coronary artery bypass (mean EF 27.5%+/- 5.5). Different variables (preoperative, intraoperative, and postoperative) were evaluated and compared. Determination of operation risk was done using EuroSCORE. Patients who underwent OPCAB were more risky due to a high percentage of associated comorbidities, mean EuroSCORE was 12.96 +/- 13.21 in comparison to 8.47 +/- 10.22 in CCAB.

RESULTS

The mean operative mortality was 8.7%. Patients who underwent OPCAB had a lower operative mortality than CCAB (6.1% vs. 10.7%) inspite of a higher preoperative predicted risk score. Completeness of revascularization was higher among the CCAB group (85.7% vs. 69.7%; p = 0.01). Subsequently, the mean number of grafts was significantly higher among this group (3.4+/-0.7 vs. 2.0 +/-0.9; p < 0.001). On the other hand, morbidity was significantly higher in CCAB (35.7% vs. 19.7%; p = 0.03). However, the incidence of both myocardial infarction and atrial fibrillation was more among OPCAB.

CONCLUSIONS

Patients with left ventricular dysfunction are high-risk group. These patients can benefit from myocardial revascularization using either off-pump or conventional CABG, but both are associated with a higher mortality and morbidity than those with normal ventricle. The use of off-pump CABG resulted in better clinical outcome and mortality, but less number of grafts performed than those with conventional CABG especially in patients with lowest EF.