Off-pump versus on-pump coronary artery bypass surgery: does the pump influence outcome?1 1No competing interests declared

Outcome of coronary endarterectomy with coronary artery bypass grafting in patients with diffuse coronary artery disease in Bangladesh: A retrospective cohort study

BACKGROUND

In this study, we aimed to review the consequences of coronary endarterectomy with coronary artery bypass grafting, and assess outcomes of this combined surgical technique for patients with diffuse coronary artery disease in a single surgeon's practice.

METHODS

We retrospectively reviewed outcome of 1198 endarterectomized coronary artery in 1000 patients with diffuse coronary artery disease, who have had experienced coronary endarterectomy with off pump coronary artery bypass grafting in between 2009 and 2016.

RESULTS

The mean age was 61.5 ± 5.5 years. Coronary endarterectomy was performed on 74.7% in the left coronary territory (43.2% left anterior descending, 26.6% diagonal, 4.9% Obtuse Marginal), and 25.3% in the right coronary territory. Post-operative intensive care unit mortality rate was 1.9%, and there were 11 (1.1%) late deaths. Mean intensive care unit stay was 36.6 ± 6.7 hours. Patients were extubated following a mean of 9.8 ± 1.25 hours. The mean duration of hospital stay was 10 ± 1 days. One-year survival rate was 97.8% and 89.5% survival rate was at 5 years follow up. However, 91.8% of patients were angina free at median follow-up of 2.5 years.

CONCLUSION

Coronary endarterectomy with off pump coronary artery bypass grafting is attainable and accomplishes surgical revascularization in coronary artery disease patients when there is no other alternative for sufficient revascularization.

Pulmonary Protection Strategies in Cardiac Surgery: Are We Making Any Progress?

Pulmonary dysfunction is a common complication of cardiac surgery. The mechanisms involved in the development of pulmonary dysfunction are multifactorial and can be related to the activation of inflammatory and oxidative stress pathways. Clinical manifestation varies from mild atelectasis to severe respiratory failure. Managing pulmonary dysfunction postcardiac surgery is a multistep process that starts before surgery and continues during both the operative and postoperative phases. Different pulmonary protection strategies have evolved over the years; however, the wide acceptance and clinical application of such techniques remain hindered by the poor level of evidence or the sample size of the studies. A better understanding of available modalities and/or combinations can result in the development of customised strategies for the different cohorts of patients with the potential to hence maximise patients and institutes benefits.

Avoidance of aortic side-clamping for proximal bypass anastomoses: better short-term outcome?

OBJECTIVES

The benefit of off-pump coronary artery bypass (OPCAB) surgery may be reduced by strokes caused by microemboli produced after aortic side-clamping for proximal bypass anastomoses. The Heartstring device allows constructing proximal bypass anastomoses without side-clamping of the aorta.

METHODS

This retrospective study describes 260 consecutive patients who underwent OPCAB surgery; 442 proximal anastomoses were performed with the Heartstring device in this series. Ten percent of the patients were randomly sampled before discharge to undergo a coronary angiogram for assessment of graft patency.

RESULTS

Intraoperative Doppler measurements confirmed regular bypass function. Early mortality occurred in 4 patients (1.5%), and stroke occurred in 2 patients (0.8%). Device-related bleeding was negligible, and there were no cases of aortic dissection. Perioperative ischemia occurred in 8 patients (3.1%). Predischarge coronary angiography evaluations in 25 of the patients (of 260) showed that all 42 Heartstring-assisted anastomoses (of 442) were patent.

CONCLUSIONS

Clampless performance of proximal bypass anastomoses combined with OPCAB is associated with a very low incidence of stroke complications. Short-term follow-up has shown excellent results regarding bypass patency and other adverse events. Prospective randomized trials are required to confirm the advantage of this technique.

Resource utilization in off-pump versus conventional coronary artery bypass grafting in a community hospital: a comparative analysis using propensity scoring

BACKGROUND

At a time when cost containment in health care is under increased scrutiny, coronary artery bypass grafting remains the most widely performed cardiac surgical procedure in the world. This study compares 30-day mortality, morbidity, and resource use for off-pump coronary artery bypass (OPCAB) versus conventional coronary artery bypass (CCAB) revascularization.

METHODS

From January 2000 through December 2008, 1003 patients underwent OPCAB grafting by a single surgeon (S.C.S.). Data were prospectively collected, entered into a Society of Thoracic Surgeons adult cardiac surgery database, and analyzed retrospectively. We used propensity-matching techniques to match this cohort to a group of 1003 patients who underwent CCAB.

RESULTS

The hospital mortality rate was lower for the OPCAB patients than for the CCAB patients: 2.0% (20/1003) versus 2.8% (28/1003). Predictors of hospital mortality for the entire cohort included age (P = .001), cardiogenic shock (P = .001), congestive heart failure (P = .019), history of myocardial infarction (P = .001), and reoperation (P = .007). The overall incidence of morbidity was lower for the OPCAB patients (reoperation for bleeding, P = .011; prolonged ventilation, P = .035; stroke, P = .045; cardiac arrest, P = .004). OPCAB patients experienced significantly reduced procedure times (P = .001), postoperative ventilation times (P = .035), post-operative lengths of stay (P = .035), and blood product use (intraoperative, P = .001; postoperative, P = .001).

CONCLUSION

These outcomes clearly demonstrate that OPCAB is a safe and effective procedure for myocardial revascularization. This retrospective, nonrandomized observational study has shown that the patients who underwent OPCAB had reduced morbidity and mortality, as well as decreased resource use, compared with those who underwent CCAB.

Sex differences in resource use after on-pump and off-pump coronary artery bypass surgery: a propensity score-matched cohort

BACKGROUND

Previous studies have demonstrated that off-pump coronary artery bypass surgery (OPCAB) is associated with less use of hospital resources compared with on-pump coronary artery bypass surgery (ONCAB).

OBJECTIVE

To determine whether there is a sex effect between the two procedures regarding resource utilization.

METHODS

Between 1996 and 2004, 13,522 patients (10,637 men and 2885 women) underwent coronary artery bypass grafting surgery at the Toronto General Hospital (Toronto, Ontario). Among the men, 10,121 patients underwent ONCAB and 516 underwent OPCAB. The female population consisted of 2723 ONCAB and 162 OPCAB patients. Both groups were matched to standard preoperative risk factors. A propensity score macro-matched 471 OPCAB men to 471 ONCAB men, and 148 OPCAB women to 148 ONCAB women.

RESULTS

The mean (+/- SD) postoperative length of stay (7.5+/-6.5 days versus 6.4+/-5.5 days; P<0.0001) was significantly higher in ONCAB compared with OPCAB in the male population. The mean length of stay in the intensive care unit and the mean ventilation time was similar between the groups. However, in the female population, there were no differences in mean postoperative length of stay (8+/-5.9 days versus 8+/-6 days; P=0.4), mean length of stay in the intensive care unit (43+/-38 h versus 53+/-81 h; P=0.4) or mean ventilation time (9.8+/-9.7 h versus 11+/-13 h; P=0.8).

CONCLUSION

These results suggest that the benefits of OPCAB in terms of hospital resource use are influenced by sex. The potential beneficial effects are not demonstrated in the female population.

Pulmonary protection during cardiac surgery: systematic literature review

Ischemia-reperfusion injury occurs during heart surgery in which cardiopulmonary bypass is used. Current knowledge of the factors contributing to postoperative pulmonary dysfunction and the measures to avoid it are reviewed.

The Influence of Diabetes Mellitus in Patients Undergoing Coronary Artery Bypass Graft Surgery: A Prospective Cohort Study

This study was conducted to prospectively assess if there are any outcome differences between patients undergoing coronary artery bypass graft surgery with and without diabetes. This is an 11-year, prospective, hospitalization cohort study. Data were collected on 225 variables. A total of 8935 patients were available for our analysis (6023 nondiabetics, 319 diet-controlled diabetics, 1636 diabetics on oral medications, 957 insulin-controlled diabetics). Compared with nondiabetics, diet-treated diabetics possessed four significant comorbidities, diabetics treated with oral medications possessed 12 significant comorbidities, and insulin-treated diabetics possessed 13 significant comorbidities ( P < 0.05). There was no significant difference between diet-treated diabetics and nondiabetics for all outcomes. Diabetics treated with oral medications possessed a longer length of stay [relative risk (RR), 1.09; CI, 1.08–1.10], longer intensive care unit length of stay (RR, 1.56; CI, 1.12–2.00), and more intraoperative complications (RR, 1.42; CI, 1.12–1.66). Insulin-treated diabetics possessed more neurological complications (RR, 2.39; CI, 1.52–3.77), wound complications (RR, 2.42; CI, 1.19–4.95), and renal complications (RR, 2.43; CI, 1.70–3.49), longer length of stay (RR, 1.20; CI, 1.14–1.27), and longer intensive care unit length of stay (RR, 1.33; CI, 1.16–1.48). In diabetics undergoing coronary artery bypass graft surgery, as their diabetes progresses from diet treated with oral medications to insulin-dependent, this is associated with more comorbidities at surgical presentation and more morbidity after surgery.

Impact of residency status on perfusion times and outcomes for coronary artery bypass graft surgery

BACKGROUND

A price of training residents in cardiothoracic surgery is often perceived to be a loss in intraoperative efficiencies, leading to prolonged cardiopulmonary bypass and perfusion time. Because these indicators are also thought to adversely affect operative outcome, we investigated the association between residency training status, perfusion times, and outcomes.

METHODS

Using the Society of Thoracic Surgeons (STS) National Cardiac Database, we studied 369,906 CABG patients undergoing isolated coronary artery bypass graft (CABG) procedures during January 2002 through June 2005. Participating institutions were stratified by residency versus nonresidency status and by perfusion time categories and analyzed for association with clinical outcomes.

RESULTS

Overall, 57 (10%) of 594 STS participants had a residency training program. Residency programs had longer mean cross-clamp and perfusion times than nonresidency programs, 73.10 versus 67.44 minutes and 104.75 versus 98.00 minutes, respectively (p < 0.0001 for both. Longer perfusion time was significantly associated with higher operative mortality at the patient level. Unadjusted mortality rates were, however, similar for patients at residency and nonresidency programs (2.30% versus 2.27%), with an adjusted odds ratio of 0.96 (95% confidence interval, 0.84 to 1.09). Although perfusion times have not changed significantly over time between residency and nonresidency programs, mortality rates have significantly improved over time at each.

CONCLUSIONS

Residency programs have longer CABG perfusion times than nonresidency cardiothoracic surgery programs, but these differences are minor. Adjusted procedural outcomes at residency training programs are similar to those at nonresidency centers; thus, patients do not appear to be adversely impacted by the time costs of surgical training.

Mechanisms of pulmonary dysfunction after on-pump and off-pump cardiac surgery: a prospective cohort study

BACKGROUND

Pulmonary dysfunction following cardiac surgery is believed to be caused, at least in part, by a lung vascular injury and/or atelectasis following cardiopulmonary bypass (CPB) perfusion and collapse of non-ventilated lungs.

METHODS

To test this hypothesis, we studied the postoperative pulmonary leak index (PLI) for 67Ga-transferrin and (transpulmonary) extravascular lung water (EVLW) in consecutive patients undergoing on-pump (n = 31) and off-pump (n = 8) cardiac surgery. We also studied transfusion history, radiographs, ventilatory and gas exchange variables.

RESULTS

The postoperative PLI and EVLW were elevated above normal in 42 and 29% after on-pump surgery and 63 and 37% after off-pump surgery, respectively (ns). Transfusion of red blood cell (RBC) concentrates, PLI, EVLW, occurrence of atelectasis, ventilatory variables and duration of mechanical ventilation did not differ between groups, whereas patients with atelectasis had higher venous admixture and airway pressures than patients without atelectasis (P = 0.037 and 0.049). The PLI related to number of RBC concentrates infused (P = 0.025).

CONCLUSION

The lung vascular injury in about half of patients after cardiac surgery is not caused by CPB perfusion but by trauma necessitating RBC transfusion, so that off-pump surgery may not afford a benefit in this respect. However, atelectasis rather than lung vascular injury is a major determinant of postoperative pulmonary dysfunction, irrespective of CPB perfusion.

The potential advantage of “no-touch” aortic technique in off-pump complete arterial revascularization

OBJECTIVES

Off-pump coronary artery bypass grafting (OPCAB) and complete arterial revascularization without proximal anastomosis to the aorta may decrease neurological events after open-heart surgery. Few reports exist regarding the combination of OPCAB and complete arterial revascularization exploring the theoretical advantage of avoiding manipulation of the aorta. We review our results in 110 patients who underwent multiple grafts off-pump complete arterial revascularization.

METHODS

110 patients underwent multiple grafts OPCAB complete arterial revascularization, and were compared to 216 patients who underwent traditional multiple grafts on pump CABG. Preoperative renal failure was 12.7% (n=14) as compared to 5.1%, (n=11, p=0.01) in the control group and 33.6% (n=37) of the patients were 75 years or older as compared to 19.0% (n=41, p=0.003) in the control group.

RESULTS

The mean number of grafts per patient undergoing multiple OPCAB complete arterial revascularization was 2.3, as compared to 3.11 in the control group (p<0.001). The mortality rate was 2.73% as compared to 1.85% (NS) in the control group. The incidence of CVA was 0% as compared to 2.31% (p=0.17) in the control group.

CONCLUSIONS

Complete arterial OPCAB revascularization without manipulation of the aorta in high-risk patients can be performed with short-term similar results to conventional CABG and very low neurological complications.

Can surgeons do complete revascularization in diabetic patients using the off-pump technique?

BACKGROUND

: The arguments are discussed as to whether or not to proceed with multivessel percutaneous coronary intervention, with or without a drug-eluting stent, in patients with diabetes mellitus (DM), including (1) surgeons unable to complete revascularization because of smaller native arteries; and (2) diabetic patients being sicker and having higher operative mortality rates than nondiabetic patients (non-DM), particularly with the conventional coronary artery bypass surgery (on-pump) technique. To support or dispute the claims, a retrospective review of 480 consecutive patients at a single institution (195 DM and 285 non-DM) was carried out. Observations were made to see whether diabetes is a predictor of poor outcomes.

MATERIALS AND METHODS

: The preoperative comorbidity, intraoperative measurement of the size of the artery at the site of anastomosis with different gauged probes, and the number of grafts per patient were recorded. Intraoperative and postoperative variables between two groups were compared. The observed number of grafts (O) after surgery was compared with the number of grafts predicted (P) before surgery. The O/P ratio or "completion index" of ≥1 signifies complete revascularization. Logistic regression analysis was used to test the possibility that diabetes is a predictor of poor outcomes.

RESULTS

: Diabetic patients were older, with more comorbidity (congestive heart failure, peripheral vascular diseases, dialysis-dependent). The number of grafts per patient was 4.2 ± 1.3 (DM) and 4.2 ± 1.3 (non-DM). The size of 742 DM and 949 non-DM arteries were gauged. There was no statistical difference in size between DM and non-DM (in millimeters) at each artery. All ratios ranged from 0.9 to 1.2, indicating similarity between DM and non-DM. The only significant risk factor for operative death was low left ventricular ejection fraction (P = 0.001).

CONCLUSIONS

: Patients with DM were sicker but tolerated off-pump coronary artery bypass grafting as well as non-DM patients. The number of grafts per patient and O/P ratio signify the ability to perform complete revascularization. We are able to bypass the small target vessels, as anticipated. Diabetes is not a predictor of the outcomes.

Early and Late Outcome After Off-Pump Coronary Artery Bypass Graft Surgery With Coronary Endarterectomy: A Single-Center 10-Year Experience

BACKGROUND

We aimed to review the early and late results of off-pump coronary artery bypass graft surgery (OPCABG) with coronary endarterectomy in patients undergoing surgical revascularization at our institution.

METHODS

Between 1995 and 2004, of 680 OPCABG patients in a single surgeon's practice (W.R.D.), 70 patients (10.29%) who underwent concomitant coronary endarterectomy were studied. The mean age was 63.6 +/- 9.29 years. Thirty-three patients (55%) were Canadian Cardiovascular Society class III or IV, and 24 patients (40%) were New York Heart Association class III or IV. Eighteen patients (35%) had impaired left ventricular function. The mean EuroSCORE of these patients was 5.9 +/- 1.8.

RESULTS

Fifty-seven patients (81%) underwent right coronary artery endarterectomy, and 12 patients (17%) underwent left anterior descending artery endarterectomy (8 left interior mammary arteries used as conduits). Four patients (5.7%) had two vessels endarterectomized. The mean number of grafts were 2.0 +/- 0.4. The 30-day mortality rate was 2.85% (n = 2). Three patients (4.3%) suffered from postoperative myocardial infarction, and 3 patients (4.3%) required postoperative intra-aortic balloon pump counterpulsation. Mean intensive therapy unit stay was 17.6 +/- 8.1 hours. Patients were extubated after a mean of 10.38 +/- 4.9 hours. The mean length of hospital stay was 6.1 +/- 2.0 days. Fourteen patients (20%) had postoperative atrial fibrillation, and only 1 patient (1.42%) had a transient stroke with complete recovery. There were no conversions to cardiopulmonary bypass. A mean of 0.86 +/- 0.17 units of blood were transfused postoperatively. There was one reopening for bleeding, and 1 patient had renal failure requiring hemofiltration. The median follow-up was 4.91 years, 90% of patients were angina free, and the actuarial survival at 10 years was 78.04% +/- 7.6%.

CONCLUSIONS

Off-pump coronary artery bypass graft survery with coronary endarterectomy is feasible and achieves surgical revascularization in patients with diffuse coronary artery disease.

Elective Intraaortic Balloon Counterpulsation in High-Risk Off-Pump Coronary Artery Bypass Grafting

The beneficial effects of intraaortic balloon pump (IABP) in CABG with cardiopulmonary bypass (CPB) have been reported. However, the benefits of insertion of IABP electively in high-risk off-pump coronary artery bypass grafting (OPCAB) have not been established. Six hundred and twenty-five patients who underwent OPCAB form the study group. High-risk patients fulfilling two or more of the following: left main stem stenosis >70%, unstable angina, and poor left ventricular function, who had elective insertion of IABP preoperatively by the open technique (group I; n = 20) were compared with a similar high-risk group that did not (group II; n = 25). There were no significant differences in risk factors between the two groups (Euroscore 5.68). The mean number of grafts was similar. Postoperatively, there were no significant differences in the need for inotropes, duration of ventilation, arrhythmias, cerebrovascular, gastrointestinal, and infective complications (p = NS). There were no IABP-related complications. Acute renal failure requiring hemofiltration was higher in group II (n = 5; p < 0.05). Four patients (16%) in group II required postoperative IABP. Although intensive care stay was longer in group I (27.6 +/- 15.3 vs. 18.6 +/- 9.1 hours; p < 0.05), patients in group I were discharged earlier from hospital. There was no difference in mortality between the two groups (n = 1 in each group). In high-risk patients undergoing OPCAB, routine preoperative insertion of IABP electively reduces the incidence of acute renal failure. In addition it avoids the need for emergency insertion postoperatively and may result in earlier discharge.

Sternal wound complications in bilateral internal thoracic artery grafting: a comparison of the off-pump technique and conventional cardiopulmonary bypass

BACKGROUND

Sternal wound complication is a major concern in bilateral internal thoracic artery grafting. The purpose of this study was to assess whether avoiding cardiopulmonary bypass has beneficial effects with fewer wound complications in patients receiving bilateral internal thoracic artery grafting.

METHODS

Retrospective review was performed using prospectively gathered data of 69 patients who had undergone elective coronary artery bypass grafting and received conventional pedicled bilateral internal thoracic artery grafting from December 2002 through April 2004 by the same surgical team. The patients were divided into 2 groups: those who underwent coronary artery bypass grafting without cardiopulmonary bypass (off-pump group, n = 41), and those who underwent coronary artery bypass grafting with cardiopulmonary bypass (CPB group, n = 28). Chart review and 3-month follow-up were obtained for all patients. These 2 groups were compared for sternal wound complications and preoperative, intraoperative, and postoperative variables.

RESULTS

Deep sternal wound infection (SWI) was seen in 1 patient (2.4%), superficial SWI in 2 patients (4.8%), and sternal dehiscence in 1 patient (2.4%) in the off-pump group. Deep SWI was seen in no patients, superficial SWI in 2 patients (7.1%) and sternal dehiscence in 2 patients (7.1%) in the CPB group. No statistically significant difference in the frequency of occurrence of sternal complications was detected between the 2 study groups.

CONCLUSIONS

The results suggest that the avoidance of CPB has no beneficial effect on the number of sternal wound complications in patients receiving bilateral internal thoracic artery grafting. However, further prospective, randomized studies on large patient groups are required to assess this finding.

Acute ischemic cardiac dysfunction is attenuated via gene transfer of a peptide inhibitor of the beta-adrenergic receptor kinase (betaARK1)

Acute myocardial ischemia is a critical adverse effect potentially occurring during cardiac procedures. A peptide inhibitor of the beta-adrenergic receptor kinase (betaARK1), betaARKct, has been successful in rescuing chronic myocardial ischemia. The present study focused on the effects of adenoviral-mediated betaARKct (Adv-betaARKct) delivery on left ventricle (LV) dysfunction induced by acute coronary occlusion. Rabbits received intracoronary delivery of phosphate-buffered saline (PBS) (n=9) or 5x10(11) viral particles of betaARKct (n=8). A loose prolene 5-0 Potz-loop suture was placed around the circumflex coronary artery (LCx) with both ends buried under the skin. Four days later, the suture was retrieved and pulled to occlude the LCx. Ischemia was confirmed by immediate ECG changes. LV function was continuously recorded for 45 min. Contractility (LVdP/dtmax), relaxation (LVdP/dtmin) and end diastolic pressure (EDP) were less impaired in the betaARKct group as compared to PBS (P<0.05, two-way ANOVA). betaAR density was higher in the ischemic area of the LV in the betaARKct group (betaARKct: 71.9+/-4.6 fmol/mg protein, PBS: 54.5+/-4.0 fmol/mg protein, P<0.05). Adenylyl cyclase activity was also improved basally and in response to betaAR stimulation. betaARK1 activation was less in the betaARKct group (P<0.05). Therefore, inhibition of myocardial betaARK1 may represent a new strategy to prevent LV dysfunction induced by acute coronary ischemia.