Off-pump coronary bypass surgery for high-risk patients: only in expert centers?

Association of Hospital Volume and Outcomes Following Off-Pump Coronary Artery Bypass Grafting

BACKGROUND

Off-pump coronary artery bypass grafting (OPCAB) has been used to mitigate the negative systemic effects of cardiopulmonary bypass. Recent consortium and single-institution studies suggest an association between operator experience and long-term survival. We thus aimed to ascertain the relationship between institutional OPCAB volume and outcomes using a contemporary nationwide all-payer database.

METHODS

Adult admissions for elective isolated OPCAB were identified from the 2016-2019 Nationwide Readmissions Database. The primary outcome was major adverse events (MAE), defined as a composite of mortality, reoperation, prolonged mechanical ventilation, acute kidney injury requiring dialysis, or perioperative stroke during the index hospitalisation. Secondary outcomes included temporal trends, postoperative length of stay (pLOS), hospitalisation costs, non-home discharge, and 30-day readmission rate. High-volume hospitals (HVH) were defined to have annual caseloads >35 based on cubic spline analysis.

RESULTS

Of an estimated 41,154 patients, 59.9% were treated at HVH. The proportion of coronary artery bypass grafting operations that were OPCAB significantly decreased from 21.1% in 2016 to 18.3% in 2019. After adjustment, HVH status was associated with lower adjusted odds of MAE (adjusted odds ratio [AOR] 0.78, 95% confidence interval [CI] 0.70-0.88), compared to others. HVH were also associated with shorter pLOS (β -0.10, 95% -0.13, -0.07), reduced costs (β -US$4,900, - US$6,300, - US$3,600), non-home discharge (AOR 0.54, 95% CI 0.45-0.64), and 30-day readmission (AOR 0.86, 95% CI 0.77-0.96).

CONCLUSIONS

Our results suggest that OPCAB requires a distinct set of surgical expertise and institutional aptitude. As a result, centralisation of care to centres of excellence should be considered.

Defining the Role of Anaortic Coronary Artery Bypass Grafting

As the population ages and co-morbidities become more prevalent, the complexity of patients presenting for coronary artery bypass surgery is increasing. Cardiopulmonary bypass and aortic cross-clamping in these patients carry increased risk and, indeed, in some patients, with ascending aortic disease, the risks are prohibitive. Total-arterial anaortic coronary artery surgery is a technique that provides complete surgical coronary artery revascularization without cardiopulmonary bypass and without manipulating the ascending aorta. The technique essentially eliminates the risk of cerebral embolization of aortic atheroma and aortic injury. Anaortic techniques are an essential skillset for coronary artery surgery centers treating higher-risk patients.

Comparative effects of on-pump versus off-pump coronary artery bypass grafting surgery on serum cytokine and chemokine levels

Coronary artery bypass grafting (CABG) surgery with two methods (on-pump or off-pump) can be used to rescue individuals with severe coronary artery disease (CAD). Each method might cause an inflammatory response, which can lead to some complications. The aim of this study was to compare the changes in serum concentrations of IFN-γ, tumor necrosis factor (TNF)-α, interleukin (IL)-1α, IL-1β, IL-2, IL-4, IL-6, IL-8, IL-10, VEGF, MCP-1, and epidermal growth factor between the two CABG surgery methods. Forty-eight patients (22 = on-pump, 26 = off-pump) who underwent on-pump or off-pump CABG surgery were enrolled in this study. Serum cytokines levels were measured in two blood samples, the first sample was taken from each patient in the morning of the day of surgery after a 12-hr fasting and the second sample on the first postoperative day at 24-hr after surgery. In baseline, comparisons between the two groups of on-pump/off-pump surgery did not show any significant difference in demographic data, anthropometric parameters, lipid profile indices, and high-sensitivity C-reactive protein levels (p > .05). There was a significant difference between the serum levels of IL-4, IL-6, IL-10, vascular endothelial growth factor (VEGF), IFN-γ, and MCP-1 in patients with on-pump surgery and a significant increase in serum IL-6 (p < .001), IL8 (p < .05), VEGF (p < .001), and IFN-γ (p < .01) levels in patients with off-pump surgery in post-operation stage compared to pre-operation. Cardiopulmonary pump in patients under CABG surgery can activate systemic inflammation and the changes of serum cytokines levels in off-pump CABG were lower compared with on-pump CABG.

Robotic Beating Heart Totally Endoscopic Coronary Artery Bypass in Higher-Risk Patients: Can It be Done Safely?

OBJECTIVE

Patients with a high Society of Thoracic Surgeons (STS) predicted risk of mortality undergoing coronary artery bypass surgery are known to have worse outcomes. Less invasive approaches have been shown to improve morbidity and mortality for these patients. In this study, we examined perioperative outcomes in higher-risk patients undergoing robotic totally endoscopic beating heart coronary artery bypass surgery.

METHODS

The STS predicted risk of mortality was reviewed for patients undergoing robotic totally endoscopic beating heart coronary artery bypass surgery at our institution between January 2013 and May 2017. We identified a higher-risk cohort (n = 50) and compared them to a lower-risk cohort (n = 220) during the same period. The higher-risk group was formed from patients with the 50 highest STS scores. Perioperative data were collected retrospectively.

RESULTS

There were 50 patients in the higher-risk group (mean STS score = 7.05 ± 4.9, mean age = 73 years) and 220 patients in the lower-risk group (mean STS score = 0.89 ± 0.6, mean age = 64 years). The higher-risk group had significantly greater rates of renal insufficiency, peripheral vascular disease, and lower ejection fraction. The incidence of postoperative re-exploration for bleeding, stroke, myocardial infarction, and prolonged ventilation was similar. Perioperative blood transfusion and hospital length of stay were greater in the higher-risk group. Mortality was lower in the higher-risk group (0% vs 1.8% P = 0.045). Cardiac-related mortality was similar at midterm follow-up.

CONCLUSIONS

We conclude that beating heart totally endoscopic beating heart coronary artery bypass surgery can be performed in patients with a higher STS predicted risk of mortality with excellent outcomes. Further studies are warranted to evaluate long-term results of totally endoscopic beating heart coronary artery bypass surgery in this challenging group of patients.

Myocardial revascularization without extracorporeal circulation; Why hasn't it convinced yet?

Extracorporeal circulation has led to a great development in cardiovascular surgery during the last five decades. Its time-proven efficacy and safety have made on-pump coronary artery bypass grafting (CABG) the gold standard method of surgical revascularization. However, coronary revascularization on cardiopulmonary bypass and the accompanying aortic manipulation are related to plenty of deleterious complications. Therefore, off-pump CABG surgery was established to avoid complications. Nevertheless, despite the initial enthusiasm on this technique, only 20% of myocardial revascularization procedures worldwide are performed off-pump. Not only are off-pump cardiac procedures more technically difficult but also they do not provide better results in terms of graft patency, completeness of revascularization, repeat revascularization requirement, cost, and quality of life. Completeness of revascularization and anastomotic quality should not be compromised to avoid cardiopulmonary bypass.

Off-pump coronary surgery: current justifications

Although the literature has failed to project an overall superiority of off-pump vs. on-pump surgery, nevertheless, small randomized control trials and large meta-analysis studies have concluded that the incidence of a stroke is less than 1 % when anaortic off-pump techniques are advocated in patients with diseased ascending aorta. Furthermore, off-pump techniques or their combination with hybrid procedures may lead to a reduction of adverse outcome in the aged high-risk population with concomitant poor left ventricular function and co-morbidities. However, despite this, controversy still exists among the cardiac surgery community in terms of the benefit of this technique and its safety; hence, off-pump is becoming out of fashion. In this review paper, by looking at a "marginal group of patients" (elderly, high risks, atherosclerotic aortas) we attempt to re-establish and justify this technique and re-invent its usage.

Optimal anticoagulation during off pump coronary artery bypass in patients recently exposed to clopidogrel

PURPOSE

The aim of this study was to find an optimal range of activated clotting time (ACT) during off-pump coronary artery bypass surgery (OPCAB) yielding ischemic protection without the risk of hemorrhagic complications in patients with recent exposure to dual antiplatelet therapy.

MATERIALS AND METHODS

Three hundred and five patients who received aspirin and clopidogrel within 7 days of isolated multi-vessel OPCAB were retrospectively studied. Combined hemorrhagic and ischemic outcome was defined as the occurrence of 1 of the following: significant perioperative bleeding (>30% of estimated blood volume), transfusion of packed red blood cell (pRBC) ≥ 2 U, or myocardial infarction (MI). This was compared in relation to the tertile distribution of the time-weighted average ACT-212-291 sec (first tertile), 292-334 sec (second tertile), 335-485 sec (third tertile).

RESULTS

The amount of perioperative blood loss was 937 ± 313 mL, 1014 ± 340 mL, and 1076 ± 383 mL, respectively (p=0.022). Significantly more patients in the third tertile developed MI (4%, 4%, and 12%, respectively, p=0.034). The incidence of significant perioperative blood loss and transfusion of pRBC ≥ 2 U were lower in the first tertile than those of other tertiles without statistical significance. In the multivariate analysis, the first tertile was associated with a 52% risk reduction of combined hemorrhagic and ischemic outcomes (95% confidence interval: 0.25-0.92, p= 0.027).

CONCLUSION

A lower degree of anticoagulation with a reduced initial heparin loading dose should be carefully considered for patients undergoing OPCAB who have recently been exposed to clopidogrel.

Trends in acute kidney injury, associated use of dialysis, and mortality after cardiac surgery, 1999 to 2008

BACKGROUND

The development of acute kidney injury (AKI) after cardiac surgery is associated with significant mortality, morbidity, and cost. The last decade has seen major changes in the complexity of cardiac surgical candidates and in the number and type of cardiac surgical procedures being performed.

METHODS

Using data from the Nationwide Inpatient Sample, we determined the annual rates of AKI, AKI requiring dialysis (AKI-D), and inpatient mortality after cardiac surgery in the United States in the years 1999 through 2008.

RESULTS

Inpatient mortality with AKI and AKI-D decreased from 27.9% and 45.9%, respectively, in 1999 to 12.8% and 35.3%, respectively, in 2008. Compared with 1999, the odds of AKI and AKI-D in 2008, adjusted for demographic and clinical factors, were 3.30 (95% confidence interval [CI]: 2.89 to 3.77) and 2.23 (95% CI: 1.78 to 2.80), respectively. Corresponding adjusted odds of death associated with AKI and AKI-D were 0.31 (95% CI: 0.26 to 0.36) and 0.47 (95% CI: 0.34 to 0.65.) Taken together, the attributable risks for death after cardiac surgery associated with AKI and AKI-D increased from 30% and 5%, respectively, in 1999 to 47% and 14%, respectively, in 2008.

CONCLUSIONS

In sum, despite improvements in individual patient outcomes over the decade 1999 to 2008, the population contribution of AKI and AKI-D to inpatient mortality after surgery increased over the same period.

Is a cell saver necessary in off-pump coronary artery bypass surgery?

BACKGROUND

Off-pump coronary artery bypass surgery should have a significantly lower risk of postoperated bleeding than on-pump surgery. However, the use of a cell saver has been considered necessary, with significant additional cost incurred. Can we consider performing off-pump coronary artery bypass surgery without a cell saver?

PATIENTS AND METHODS

A prospective observational study was performed in 68 consecutive patients operated on for 2- or 3-vessel coronary lesions by the off-pump technique.

RESULTS

The mean number of distal anastomoses was 2.7 ± 0.7. Both internal thoracic arteries were used in 45 patients, and sequential revascularization was performed in 27, with 140 (77.8%) arterial grafts. Cell savers were used in 21 (30.9%) patients. In these 21 patients, the mean volume retransfused after treatment was 315 ± 177 mL. Postoperatively, 11 (16.2%) patients were transfused with packed red blood cells, with a mean volume of 636 ± 234 mL per patient. The 2 factors identified as associated with a higher risk of autotransfusion were female sex and a lower preoperative hemoglobin.

CONCLUSIONS

The use of a cell saver in off-pump surgery is useless in most cases. Careful surgical hemostasis is essential to limit hypovolemia.

Significance of off-pump coronary artery bypass grafting compared with percutaneous coronary intervention: a propensity score analysis

OBJECTIVE

Although there have been several studies that compared the efficacy of percutaneous coronary intervention (PCI) and coronary artery bypass grafting (CABG), the impact of off-pump CABG (OPCAB) has not been well elucidated. The objective of the present study was to compare the outcomes after PCI, on-pump CABG (ONCAB), and OPCAB in patients with multivessel and/or left main disease.

METHODS

Among the 9877 patients undergoing first PCI using bare-metal stents or CABG who were enrolled in the CREDO-Kyoto Registry, 6327 patients with multivessel and/or left main disease were enrolled into the present study (67.9±9.8 years old). Among them, 3877 patients received PCI, 1388 ONCAB, and 1069 OPCAB. Median follow-up was 3.5 years.

RESULTS

Comparing PCI with all CABG (ONCAB and OPCAB), propensity-score-adjusted all-cause mortality after PCI was higher than that CABG (hazard ratio (95% confidence interval): 1.37 (1.15-1.63), p<0.01). The incidence of stroke was lower after PCI than that after CABG (0.75 (0.59-0.96), p=0.02). CABG was associated with better survival outcomes than PCI in the elderly (interaction p=0.04). Comparing OPCAB with PCI or ONCAB, propensity-score-adjusted all-cause mortality after PCI was higher than that after OPCAB (1.50 (1.20-1.86), p<0.01). Adjusted mortality was similar between ONCAB and OPCAB (1.18 (0.93-1.51), p=0.33). The incidence of stroke after OPCAB was similar to that after PCI (0.98 (0.71-1.34), p>0.99), but incidence of stroke after ONCAB was higher than that after OPCAB (1.59 (1.16-2.18), p<0.01).

CONCLUSIONS

In patients with multivessel and/or left main disease, CABG, particularly OPCAB, is associated with better survival outcomes than PCI using bare-metal stents. Survival outcomes are similar between ONCAB and OPCAB.

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.

Risks of Stroke After Coronary Artery Bypass Graft - Recent Insights and Perspectives

Stroke is one of the most devastating complications after coronary artery bypass graft (CABG) surgery, entailing permanent disability, a 3-6 fold increased risk of mortality, an incremental hospital resource consumption and a longer length of hospital stay. Notwithstanding advances in surgical, anaesthetic and medical management across the last 10 years, the risk of stroke after CABG has not significantly declined, likely because an older and sicker population is now deemed suitable to undergo CABG. The pathogenesis of stroke is multifactorial, but two variables are believed to play a major role - cerebral embolisation of atheromatous debris arising from the ascending aorta during surgical manipulation and hypoperfusion during surgery. Identification of vulnerable patients at increased risk of stroke before CABG is of paramount importance for the surgical decision-making approach and informed consent. Several models including demographic, clinical and procedural variables have been developed to risk-stratify the hazard of stroke in patients undergoing CABG, but identification of severe atherosclerosis of the ascending aorta and pre-existing cerebrovascular disease are key determinants for appropriate risk stratification and decision-making. Atherosclerotic disease of the ascending aorta can be identified before surgery using transoesophageal echocardiography, computed tomography and magnetic resonance imaging. However, intra-operative ultrasound scanning of the ascending aorta is the diagnostic tool with the best sensitivity and specificity for the detection of atheromatous debris in the ascending aorta. Although many investigators have advocated the use of off-pump CABG to minimise the risk of peri-operative stroke, results from randomised trials and meta-analyses have been inconsistent. Anaortic approaches, including total arterial revascularisation with in situ grafting of both mammary arteries, or the use of the HEARTSTRING® seal device avoid any manipulation of the aorta, thus potentially minimising the risk of stroke in high-risk patients. Assessment and treatment of severe carotid artery disease, and aggressive and prompt treatment of post-operative atrial fibrillation are other important strategies that should be routinely implemented to reduce the risk of stroke in patients undergoing CABG.

Off-pump coronary artery bypass surgery in selected patients is superior to the conventional approach for patients with severely depressed left ventricular function

OBJECTIVES

Patients with coronary artery disease and left ventricular dysfunction have high mortality when kept in clinical treatment. Coronary artery bypass grafting can improve survival and the quality of life. Recently, revascularization without cardiopulmonary bypass has been presented as a viable alternative. The aim of this study is to compare patients with left ventricular ejection fractions of less than 20% who underwent coronary artery bypass graft with or without cardiopulmonary bypass.

METHODS

From January 2001 to December 2005, 217 nonrandomized, consecutive, and nonselected patients with an ejection fraction less than or equal to 20% underwent coronary artery bypass graft surgery with (112) or without (off-pump) (105) the use of cardiopulmonary bypass. We studied demographic, operative, and postoperative data.

RESULTS

There were no demographic differences between groups. The outcome variables showed similar graft numbers in both groups. Mortality was 12.5% in the cardiopulmonary bypass group and 3.8% in the off-pump group. Postoperative complications were statistically different (cardiopulmonary bypass versus off-pump): total length of hospital stay (days)-11.3 vs. 7.2, length of ICU stay (days)-3.7 vs. 2.1, pulmonary complications-10.7% vs. 2.8%, intubation time (hours)-22 vs. 10, postoperative bleeding (mL)-654 vs. 440, acute renal failure-8.9% vs. 1.9% and left-ventricle ejection fraction before discharge-22% vs. 29%.

CONCLUSION

Coronary artery bypass grafting without cardiopulmonary bypass in selected patients with severe left ventricular dysfunction is valid and safe and promotes less mortality and morbidity compared with conventional operations.

Comparison of inflammatory response during on-pump and off-pump coronary artery bypass surgery

PURPOSE

On-pump coronary artery bypass graft (CABG) surgery has been traditionally associated with a higher magnitude of inflammatory response than off-pump CABG. However with the development of polymer-coated biocompatible extracorporeal circuits, we wanted to see if cardiopulmonary bypass still played an important role in triggering this inflammatory response.

METHODS

In this prospective observational study, 33 patients undergoing CABG surgeries (25 on-pump and 8 off-pump patients) were studied. Serial plasma cytokine (TNF IL-6, IL-10) and procalcitonin concentrations were measured at different time-points during and after the surgery. Demographic and baseline clinical data, intra-operative management details and post-operative complications were also collected from the patients' charts.

RESULTS

Plasma levels of all 4 mediators increased during surgery and returned towards normal postoperatively. There were no differences between groups for any mediator at any time-point.

CONCLUSIONS

We conclude that with the use of recent polymer-coated biocompatible extracorporeal circuits, the inflammatory response triggered by on-pump CABG becomes very similar in magnitude and pattern to that triggered by off-pump CABG. Thus, the surgical procedure contributes to most of the inflammatory response, with the extra-corporeal circuit having minimal to no effect on this response.

Off-pump coronary artery revascularization in octogenarians: is it better?

PURPOSE OF REVIEW

Octogenarians are the fastest growing stratum of the population and have the highest prevalence of coronary artery disease. In the past, physicians have been reluctant to provide these patients with optimal care. Seniors are frequently excluded from large randomized trials and generally not included in published guidelines. The purpose of this review is to revisit the demography and epidemiology of coronary artery disease in this population as well as therapeutic strategies used.

RECENT FINDINGS

Recent publications have shown significant advancement in medical and invasive treatment of coronary artery disease in elderly, with special focus on the potential benefit of off-pump coronary artery bypass (OPCAB) surgery.

SUMMARY

Although OPCAB surgery has gained popularity over the past 15 years, its benefit regarding operative mortality and major complications has not been clearly defined in the general population. There is a body of literature supporting its benefit in the elderly population. OPCAB surgery has the potential of decreasing operative mortality and major postoperative complications such as stroke, delirium, atrial fibrillation, and decline in neurocognitive functions in these patients. Off-pump surgery is technically more demanding and has been blamed for providing less complete revascularization and lower graft patency rate, especially in less experienced hands. However, with the upcoming demographic explosion of senior citizens in western societies, OPCAB surgery has definitely to be a part of the armamentarium of modern cardiac surgeons.

Off-pump coronary artery bypass: techniques, pitfalls, and results

In an attempt to advance the surgical treatment of coronary artery disease, surgeons sought a way to offer the proven benefits of coronary revascularization and avoid the side effects of cardiopulmonary bypass by performing revascularization in the beating heart (off-pump coronary artery bypass). This review will describe the development and refinement of the technique, pitfalls to its widespread adoption, and an up-to-date assessment of current results.