Current outcomes of off-pump versus on-pump coronary artery bypass grafting: evidence from randomized controlled trials

Long-Term Outcomes After Hybrid Coronary Revascularization Versus Coronary Artery Bypass Grafting: Meta-Analysis of Kaplan-Meier-Derived Data

Hybrid coronary revascularization (HCR) is an alternative option to conventional coronary artery bypass grafting (CABG), but the long-term outcomes of HCR versus CABG remain unclear. We aimed to analyze the long-term outcomes after HCR and CABG for patients with multivessel coronary artery disease using meta-analysis. A systemic literature search of PubMed and EMBASE was performed from inception to March 2023. Studies reporting Kaplan-Meier curves with follow-up ≥1 year were included. The primary outcome was all-cause mortality, and the secondary outcomes were major adverse cardiac and cerebrovascular events (MACCEs) and repeat revascularization. In total, 13 studies (1 randomized controlled trial and 12 propensity-score matched observational studies) were analyzed. The mean follow-up period was 5.1 ± 3.1 years. HCR was associated with similar overall mortality (hazard ratio [HR] 1.09, 95% confidence interval [CI] 0.87 to 1.36), significantly higher incidence of MACCEs (HR 1.49, 95% CI 1.07 to 2.06), and repeat revascularization (HR 2.01, 95% CI 1.53 to 2.64) compared with CABG. In phase-specific analysis, the mortality rate was similar, and the incidence of repeat revascularization was higher in HCR regardless of phases. The incidence of MACCEs was higher in HCR during the mid-term phase (1 to 5 years), but it was similar during the long-term phase (long-term: ≥5 years). In conclusion, despite the higher incidence of MACCEs and repeat revascularization compared with CABG, HCR offered a similar long-term survival. Even longer-term follow-up and randomized controlled trials with a large population are warranted to investigate the role of HCR for multivessel coronary artery disease.

The gut microbiome and cardiac surgery an unusual symphony

The relationship between the gut microbiome and various organ systems has gained interest throughout the scientific community in recent times. The understanding of these complex relationships has greatly improved with clinical benefits now being seen. Cardiopulmonary bypass (CPB) is a form of extracorporeal circulation that provides circulatory and respiratory support during cardiac surgery. This physiological support facilitates a still and bloodless field facilitating operations on the heart to be performed. Through various mechanisms CPB results in a systemic inflammatory response syndrome (SIRS). This response can vary from mild hypotension to multiple organ failure. It remains difficult to predict the degree to which a patient will experience SIRS post-operatively. The relationship between the composition of the gut microbiome and inflammatory processes associated with disease has been seen across several fields including gastroenterology, neurology, psychiatry and cardiology. To date, minimal research has been undertaken to examine the impact the gut microbiome has on outcomes following cardiac surgery. This review paper explores the pathophysiology behind the SIRS response associated with CPB for cardiac surgery and the hypothesis that a correlation exists between a patients gut microbiome composition and the degree of inflammatory response experienced following cardiac surgery.

Trend and early clinical outcomes of off-pump coronary artery bypass grafting in the UK

OBJECTIVES

The popularity of off-pump coronary artery bypass grafting (CABG) varies across the world, ranging from 20% in Europe and the USA to 56% in Asia. We present the trend and early clinical outcomes in off pump in the UK.

METHODS

All patients who underwent elective or urgent isolated CABG from 1996 to 2019 were extracted from the National Adult Cardiac Surgery Audit database. The trend in operating surgeons and units volume and training in off pump were analysed. Early clinical outcomes between off- and on-pump CABG were compared using propensity score matching.

RESULTS

A total of 351 422 patients were included. The overall off-pump rate during the study period was 15.17%, it peaked in 2008 (19.8%), followed by a steady decreased to 2018 (7.63%). Its adoption varied across centres and surgeons, ranging from <1% to 48.36% and <1% to 85.5%, respectively, of total cases performed. After propensity score matching for the period 1996-2019, off pump, when compared to on pump, was associated with a lower in-hospital/30-day mortality (1.2% vs 1.5%, P < 0.001), return to theatre (3.7% vs 4.5%, P < 0.001), cerebrovascular accident (transient ischaemic attack: 0.3% vs 0.6%, stroke: 0.3% vs 0.6%, P < 0.001) and deep sternal wound infection (0.8% vs 1.2%, P ≤ 0.001). In a sub-analysis from the introduction of EuroScore II (2012-2019), there were no differences in-hospital/30-day mortality (1.0% vs 1.0%, P = 0.71). However, on pump, had a higher return to theatre (4.2% vs 2.7%, P < 0.001), cerebrovascular accident (transient ischaemic attack: 0.4% vs 0.2%, stroke: 0.5% vs 0.3%, P = 0.003) and deep sternal wound infection (1.0% vs 0.6%, P = 0.004).

CONCLUSIONS

Our data show a decreasing trend in the use of off pump in the UK since 2008. This is likely to be multifactorial and raises the question of whether it should be a specialized revascularization technique.

Quality control in a training course of off-pump coronary artery bypass grafting surgery

Objectives

Off-pump coronary artery bypass grafting (OPCAB) surgery is controversial in part because of the surgeon's experience, which correlates with how the surgeon is trained. Because the training model of OPCAB is not uniform, the quality control in the training process seems to be more important and needs to be further discussed.

Methods

Nine surgeons accepted and completed an OPCAB training course at a single center to become independent surgeons. This training program is characterized by 6 progressive levels supervised by experienced trainers. In total, 2307 consecutive cases of OPCAB performed by the 9 trainee surgeons were analyzed for monitoring and evaluation in quality control. The funnel plots and cumulative summation (CUSUM) analysis method were used to evaluate the performance of each surgeon.

Results

The mortality and complications of each surgeon were all within the 95% confidence interval of funnel plots. The CUSUM learning curves of first 3 trainees was analyzed and showed that the trainees need to complete approximately 65 cases to cross the CUSUM learning curve to reach a steady state.

Conclusions

The trainees can directly receive the OPCAB training course under the guidance of experienced surgeons with a rigorous schedule. It is feasible to perform quality control by funnel plots and CUSUM method in OPCAB surgery to ensure the safety of the training course.

Repeat Coronary Artery Bypass Grafting: A Meta-Analysis of Off-Pump versus On-Pump Techniques in a Large Cohort of Patients

BACKGROUND

Redo coronary artery bypass grafting (CABG) can be performed with either the off-pump (OPCAB) or the on-pump (ONCAB) technique.

METHOD

Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), this meta-analysis compared the safety and efficacy of OPCAB versus ONCAB redo CABG.

RESULTS

Twenty-three (23) eligible studies were included (OPCAB, n=2,085; ONCAB, n=3,245). Off-pump CABG significantly reduced the risk of perioperative death (defined as in-hospital or 30-day death rate), myocardial infarction, atrial fibrillation, and acute kidney injury. The two treatment approaches were comparable regarding 30-day stroke and late all-cause mortality.

CONCLUSIONS

Off-pump redo CABG resulted in lower perioperative death and periprocedural complication rates. No difference was observed in perioperative stroke rates and long-term survival between the two techniques.

Impact of avoiding cardioplegic arrest on clinical outcome in patients undergoing CABG in Bangladesh: a systematic review and meta-analysis

Objectives

Over the last decade, the practice of surgical revascularization for the coronary artery disease has been popularized in Bangladesh. Our aim was to compare the outcome of non-cardioplegic versus cardioplegic coronary artery bypass surgery in terms of early postoperative outcomes.

Methods

A literature search was conducted in March 2020 on Medline (via PubMed), Scopus and Bangladesh Journal Online electronic databases according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. All randomized controlled trials and observational studies reporting findings of coronary revascularization surgery comparing the outcomes were included.

Results

Fifteen studies were used quantitatively that included a total cohort of 4750 coronary artery bypass graft (CABG) patients in Bangladesh. After the meta-analysis, we observed a longer duration of operating time [mean difference (MD): - 52.30, confidence interval (CI): - 67.73 to - 36.86, I ² 18 = 89%, p < 0.00001] and a higher incidence of postoperative atrial fibrillation [risk ratio (RR): 0.43, CI: 0.14 to 0.80, I ² = 44%, p = 0.01] in the cardioplegic CABG group as compared with the non-cardioplegic group. Additionally, statistically significant longer duration of ventilation time (MD: - 8.64, CI: - 9.47 to - 7.82, I ² = 82%, p < 0.00001) and ICU stay (MD: - 17.25, CI: - 33.36 to - 1.14, I ² = 99%, p = 0.04) was observed in the cardioplegic group. No significant differences in number of grafts and in-hospital mortality were found between the two groups.

Conclusion

Non-cardioplegic CABG may be a viable alternative to cardioplegic CABG in Bangladeshi population, providing similar postoperative outcomes but offering additional advantage of shorter operation and ventilation times.

Timing of Recognition for Perioperative Strokes Following Cardiac Surgery

INTRODUCTION

More than half of reported perioperative strokes following cardiac surgery are identified beyond postoperative day one. The objective of our study was to determine preoperative and intraoperative factors that are associated with stroke following cardiac surgery and to identify factors that may contribute delayed recognition of perioperative stroke.

METHODS

Patients undergoing coronary artery bypass surgery or isolated valve surgery from January 2, 2015 to April 28, 2017 at an academic health system were identified from the Society of Thoracic Surgeons Registry. We determined preoperative and intraoperative factors associated with perioperative stroke. Two neurologists performed retrospective chart reviews on perioperative stroke patients to determine the last seen well time and the stroke cause.

RESULTS

During the study period, 2795 patients underwent coronary artery bypass surgery or isolated valve surgery (mean age 64 ± 11 years, 71% male, 72% Caucasian, 9% history of stroke), of which 43 (1.5%) had a perioperative stroke; 31 (72%) patients had an embolic mechanism of stroke based on neuroimaging. In multivariable analysis, perioperative strokes were independently associated with increasing age (OR 1.04, 95% 1.01-1.07), history of stroke (OR 2.73, 95% CI 1.47-5.06), and history of thoracic aorta disease (OR 3.36, 95% CI 1.16-9.71). Strokes were identified after postoperative day one in 32 (74%) patients of which 26 (81%) had a preoperative last seen well time.

CONCLUSION

Given the high frequency of preoperative last seen well time in perioperative stroke patients who are identified after postoperative day one, delayed stroke recognition may contribute to the bimodal distribution in timing of perioperative stroke. Frequent neurological monitoring within 24 hours after CABG or isolated valve surgery should be considered for all patients undergoing cardiac surgery, particularly elderly patients and those with a history of stroke or thoracic aorta disease, to improve early stroke recognition.

Does Intolerance of Single-Lung Ventilation Preclude Robotic Off-Pump Totally Endoscopic Coronary Bypass Surgery?

Objective

Robotic off-pump totally endoscopic coronary artery bypass (TECAB) usually requires isolated single (right) lung ventilation to adequately expose the surgical site. However, in some patients, persistent oxygen desaturation may occur and conversion to cardiopulmonary bypass (CPB) or sternotomy may be necessary. We reviewed the characteristics and clinical outcomes in patients who did not tolerate single-lung ventilation during TECAB surgery.

Methods

After Institutional Review Board approval we reviewed 440 patients undergoing robotic TECAB at our institution between July 2013 and April 2019. Patients were separated into 2 groups based on their ability to tolerate single-lung ventilation during the procedure. Group 1 included patients able to tolerate single-lung ventilation and Group 2 were patients who required double-lung ventilation to tolerate the procedure. Early and mid-term outcomes were compared.

Results

Group 2 (121 patients) had higher Society of Thoracic Surgeons scores, higher body mass index, and more triple-vessel disease than Group 1 (319 patients). Group 2 had more bilateral internal mammary artery use, multivessel grafting, and longer operative times. One patient underwent conversion to sternotomy and 5 required CPB (all in Group 1). Intensive care unit and hospital length of stay were longer in Group 2. Observed/expected mortality did not differ between groups (1.06% in Group 2 vs 0.4% in Group 1; P = 0.215). At mid-term follow-up, cardiac-related/overall mortality and freedom from major adverse cardiac events were similar.

Conclusions

In our cohort, intolerance of single-lung ventilation did not preclude robotic off-pump TECAB. Double-lung ventilation is feasible during the procedure and may prevent conversions to sternotomy or use of CPB, resulting in excellent early and mid-term outcomes.

Effect of octopus tissue stabilizer on cardiac output during off-pump coronary artery bypass graft surgery

Introduction

Significant hemodynamic derangements can occur during off-pump coronary artery bypass graft (OPCAB) surgery resulting from the displacement of the beating heart, which may necessitate conversion to on-pump surgery.

Aim

We proposed to evaluate the alterations in hemodynamic parameters in patients during the course of anastomosis in OPCAB surgery using the Octopus tissue stabilizer.

Material and methods

In 100 consecutive patients undergoing OPCAB surgery, hemodynamic variables including cardiac output (CO), heart rate (HR), mean arterial pressure (MAP) and central venous pressure (CVP) were recorded at baseline, during each coronary artery anastomosis at 2 min, 10 min and after release of the Octopus tissue stabilizer.

Results

CO decreased significantly after target stabilization and during all coronary anastomoses (5.42 ±1.1 l/min at baseline, 4.26 ±1.02 l/min at 2 min and 3.92 ±0.98 l/min at 10 min; p < 0.001), with the greatest decrease noted during obtuse marginal (OM) branch of left circumflex artery anastomosis (3.67 ±0.86 l/min at 2 min and 3.38 ±0.78 l/min at 10 min). Inotropic drugs were required to maintain mean arterial pressure (MAP) > 60 mm Hg in 43 patients, which was most frequently noted during OM anastomosis (p < 0.001). The incidence of bradycardia requiring inotropes was noted to be the highest during left anterior descending (LAD) artery anastomosis (p = 0.002).

Conclusions

During OPCAB surgery using the Octopus for coronary target stabilization, CO decreased the most during OM anastomosis requiring inotropes, while bradycardia was most frequent during LAD anastomosis. Careful monitoring and management of hemodynamic variables are therefore of utmost importance to avoid conversion to on-pump surgery.

Optimisation of laboratory methods for whole transcriptomic RNA analyses in human left ventricular biopsies and blood samples of clinical relevance

This study aimed to optimise techniques for whole transcriptome and small RNA analyses on clinical tissue samples from patients with cardiovascular disease. Clinical samples often represent a particular challenge to extracting RNA of sufficient quality for robust RNA sequencing analysis, and due to availability, it is rarely possible to optimise techniques on the samples themselves. Therefore, we have used equivalent samples from pigs undergoing cardiopulmonary bypass surgery to test different protocols for optimal RNA extraction, and then validated the protocols in human samples. Here we present an assessment of the quality and quantity of RNA obtained using a variety of commercially-available RNA extraction kits on both left ventricular biopsies and blood plasma. RNA extraction from these samples presents different difficulties; left ventricular biopsies are small and fibrous, while blood plasma has a low RNA content. We have validated our optimised extraction techniques on human clinical samples collected as part of the ARCADIA (Association of non-coding RNAs with Coronary Artery Disease and type 2 Diabetes) cohort study, resulting in successful whole transcriptome and small RNA sequencing of human left ventricular tissue.

Ligature of the Left Main Coronary Artery after Surgery in Kawasaki Disease: Case Report

We report a case of a 23-year-old man who was diagnosed with Kawasaki disease that progressed to a coronary aneurysm in the left main coronary artery (LMA). He had suffered from acute coronary syndrome and then underwent an emergent percutaneous coronary angioplasty, in which a polyurethane-covered stent was placed inside the aneurysm. The stent was thrombosed one year later, despite the patient had been treated with anticoagulant and antiplatelet therapy. Emergency percutaneous intervention was then performed. LMA was reopened and stent malposition was observed. Therefore, urgent coronary bypass grafting was performed in which a high degree of competitive flow was observed through the reopened stent. LMA was ligated at the inflow of the aneurysm, resulting in an improvement of graft flow. Left main ligature has not been previously reported.

Comparison of intestinal ischemia after on-pump versus off-pump coronary artery bypass grafting surgery

Background/aim

Acute mesenteric ischemia (AMI), one of the gastrointestinal system complications, which occurs following cardiac surgery, is challenged in the literature with a diminished incidence of AMI by heart surgery without cardiopulmonary bypass (CPB) or with pulsatile CPB. This study aims to compare the incidence and mortality rate of mesenteric ischemia in a series of consecutive patients undergoing coronary artery bypass grafting (CABG) through on-pump and off-pump techniques.

Materials and methods

This study included patients who underwent CABG between 1 January 2010 and 31 June 2016. All patients were divided into two groups: Group 1 comprised 6396 CABG patients operated on with the off-pump technique. Group 2 included 1210 patients who received CABG with the on-pump technique. Preoperative data were collected on the studied variables. Postoperative data included the development of intestinal ischemia and in-hospital mortality.

Results

Of 7606 consecutive CABG patients, a total of 31 (0.4%) developed intestinal ischemia. The incidence of postoperative mesenteric ischemia was 0.28% in Group 1 and 1.07% in Group 2 (P = 0.000). The survival rates after AMI were 61.1% in Group 1 (off-pump) and 7.7% in Group 2 (on-pump) (P = 0.003). Time from the first occurrence of nonspecific GI complaints to laparotomy was similar in the off-pump and on-pump groups and had no effect on mortality.Conclusions: With regard to the incidence of mesenteric ischemia and survival after laparotomy, off-pump CABG patients revealed significant improvement compared with those operated on with the on-pump technique.

Off- vs. On-Pump Coronary Artery Bypass Grafting Long-Term Survival is Driven by Incompleteness of Revascularisation

BACKGROUND

Off-pump coronary artery bypass grafting (CABG) negates the requirement for extracorporeal circulation used with the traditional on-pump approach. However, off-pump CABG is technically more challenging and may theoretically lead to less complete revascularisation. Recent data suggests a prognostic benefit for traditional on-pump CABG, but the mechanism for this remains unclear. We hypothesised that the inferior outcomes with off-pump CABG could be driven by the need for repeat revascularisation, with this benefit only becoming clear at long-term follow-up. We therefore evaluated short, medium and long-term outcomes of patients undergoing revascularisation with on vs. off-pump CABG.

METHODS

Electronic databases were searched to identify suitable randomised controlled trials enrolling ≥100 patients in each arm. Clinical outcomes were extracted at 30-days, 12-months or >4years. The primary outcome was long-term all-cause death, while secondary outcomes included 30-day, 12-month and >4-year cardiac death, stroke, myocardial infarction or revascularisation.

RESULTS

Thirteen (13) studies comprising 13,234 patients were included. Off-pump CABG was associated with an increased risk of all-cause death (Odds Ratio [OR] 1.18, 95% confidence interval [CI] 1.02-1.32, p=0.01) and repeat bypass surgery (OR 2.57, 95%CI 1.23-5.39, p=0.01) at long-term follow-up. A significant, increased requirement for revascularisation in off-pump was seen at 12-month follow-up (OR 1.59, 95%CI 1.09-2.33, p=0.02). No differences were noted between groups at 30-days, 12-months and >4years for myocardial infarction or stroke.

CONCLUSIONS

Off-pump CABG is associated with significantly higher rates of all-cause mortality rate at long-term follow-up. These outcomes demonstrate a temporal relationship that may be driven by a greater requirement for repeat revascularisation at 1- and 5-year follow-up.

STUDY REGISTRATION

CRD42018102019 (PROSPERO).

Automated Weaning from Mechanical Ventilation after Off-Pump Coronary Artery Bypass Grafting

BACKGROUND

The discontinuation of mechanical ventilation after coronary surgery may prolong and significantly increase the load on intensive care unit personnel. We hypothesized that automated mode using INTELLiVENT-ASV can decrease duration of postoperative mechanical ventilation, reduce workload on medical staff, and provide safe ventilation after off-pump coronary artery bypass grafting (OPCAB). The primary endpoint of our study was to assess the duration of postoperative mechanical ventilation during different modes of weaning from respiratory support (RS) after OPCAB. The secondary endpoint was to assess safety of the automated weaning mode and the number of manual interventions to the ventilator settings during the weaning process in comparison with the protocolized weaning mode.

MATERIALS AND METHODS

Forty adult patients undergoing elective OPCAB were enrolled into a prospective single-center study. Patients were randomized into two groups: automated weaning (n = 20) using INTELLiVENT-ASV mode with quick-wean option; and protocolized weaning (n = 20), using conventional synchronized intermittent mandatory ventilation (SIMV) + pressure support (PS) mode. We assessed the duration of postoperative ventilation, incidence and duration of unacceptable RS, and the load on medical staff. We also performed the retrospective analysis of 102 patients (standard weaning) who were weaned from ventilator with SIMV + PS mode based on physician's experience without prearranged algorithm.

RESULTS AND DISCUSSION

Realization of the automated weaning protocol required change in respiratory settings in 2 patients vs. 7 (5-9) adjustments per patient in the protocolized weaning group. Both incidence and duration of unacceptable RS were reduced significantly by means of the automated weaning approach. The FiO₂ during spontaneous breathing trials was significantly lower in the automated weaning group: 30 (30-35) vs. 40 (40-45) % in the protocolized weaning group (p < 0.01). The average time until tracheal extubation did not differ in the automated weaning and the protocolized weaning groups: 193 (115-309) and 197 (158-253) min, respectively, but increased to 290 (210-411) min in the standard weaning group.

CONCLUSION

The automated weaning system after off-pump coronary surgery might provide postoperative ventilation in a more protective way, reduces the workload on medical staff, and does not prolong the duration of weaning from ventilator. The use of automated or protocolized weaning can reduce the duration of postoperative mechanical ventilation in comparison with non-protocolized weaning based on the physician's decision.