ISMICS Consensus Conference and Statements of Randomized Controlled Trials of Off-Pump versus Conventional Coronary Artery Bypass Surgery

Effects of interventions targeting the systemic inflammatory response to cardiac surgery on clinical outcomes in adults

BACKGROUND

Organ injury is a common and severe complication of cardiac surgery that contributes to the majority of deaths. There are no effective treatment or prevention strategies. It has been suggested that innate immune system activation may have a causal role in organ injury. A wide range of organ protection interventions targeting the innate immune response have been evaluated in randomised controlled trials (RCTs) in adult cardiac surgery patients, with inconsistent results in terms of effectiveness.

OBJECTIVES

The aim of the review was to summarise the results of RCTs of organ protection interventions targeting the innate immune response in adult cardiac surgery. The review considered whether the interventions had a treatment effect on inflammation, important clinical outcomes, or both.

SEARCH METHODS

CENTRAL, MEDLINE, Embase, conference proceedings and two trial registers were searched on October 2022 together with reference checking to identify additional studies.

SELECTION CRITERIA

RCTs comparing organ protection interventions targeting the innate immune response versus placebo or no treatment in adult patients undergoing cardiac surgery where the treatment effect on innate immune activation and on clinical outcomes of interest were reported.

DATA COLLECTION AND ANALYSIS

Searches, study selection, quality assessment, and data extractions were performed independently by pairs of authors. The primary inflammation outcomes were peak IL-6 and IL-8 concentrations in blood post-surgery. The primary clinical outcome was in-hospital or 30-day mortality. Treatment effects were expressed as risk ratios (RR) and standardised mean difference (SMD) with 95% confidence intervals (CI). Meta-analyses were performed using random effects models, and heterogeneity was assessed using I2.

MAIN RESULTS

A total of 40,255 participants from 328 RCTs were included in the synthesis. The effects of treatments on IL-6 (SMD -0.77, 95% CI -0.97 to -0.58, I2 = 92%) and IL-8 (SMD -0.92, 95% CI -1.20 to -0.65, I2 = 91%) were unclear due to heterogeneity. Heterogeneity for inflammation outcomes persisted across multiple sensitivity and moderator analyses. The pooled treatment effect for in-hospital or 30-day mortality was RR 0.78, 95% CI 0.68 to 0.91, I2 = 0%, suggesting a significant clinical benefit. There was little or no treatment effect on mortality when analyses were restricted to studies at low risk of bias. Post hoc analyses failed to demonstrate consistent treatment effects on inflammation and clinical outcomes. Levels of certainty for pooled treatment effects on the primary outcomes were very low.

AUTHORS' CONCLUSIONS

A systematic review of RCTs of organ protection interventions targeting innate immune system activation did not resolve uncertainty as to the effectiveness of these treatments, or the role of innate immunity in organ injury following cardiac surgery.

Perioperative transfusion and long-term mortality after cardiac surgery: a meta-analysis

OBJECTIVES

Cardiac surgical procedures are associated with a high incidence of periprocedural blood loss and blood transfusion. Although both may be associated with a range of postoperative complications there is disagreement on the impact of blood transfusion on long-term mortality. This study aims to provide a comprehensive review of the published outcomes of perioperative blood transfusion, examined as a whole and by index procedure.

METHODS

A systematic review of perioperative blood transfusion cardiac surgical patients was conducted. Outcomes related to blood transfusion were analysed in a meta-analysis and aggregate survival data were derived to examine long-term survival.

RESULTS

Thirty-nine studies with 180,074 patients were identified, the majority (61.2%) undergoing coronary artery bypass surgery. Perioperative blood transfusions were noted in 42.2% of patients and was associated with significantly higher early mortality (OR 3.87, p < 0.001). After a median of 6.4 years (range 1-15), mortality remained significantly higher for those who received a perioperative transfusion (OR 2.01, p < 0.001). Pooled hazard ratio for long-term mortality similar for patients who underwent coronary surgery compared to isolated valve surgery. Differences in long-term mortality for all comers remained true when corrected for early mortality and when only including propensity matched studies.

CONCLUSIONS

Perioperative red blood transfusion appears to be associated with a significant reduction in long-term survival for patients after cardiac surgery. Strategies such as preoperative optimisation, intraoperative blood conservation, judicious use of postoperative transfusions, and professional development into minimally invasive techniques should be utilised where appropriate to minimise the need for perioperative transfusions.

Minimally invasive off-pump anaortic coronary artery bypass (MACAB)

BACKGROUND

Minimally invasive direct coronary artery bypass has enabled coronary artery bypass graft to compete with the appeal of less invasive percutaneous coronary procedures. Favorable results of coronary artery bypass surgery performed without the use of cardiopulmonary bypass and without touching the aorta (anOPCAB) have enabled the development and use of minimally invasive methods.

METHODS

Between 2016 and 2021, 112 patients underwent multivessel coronary bypass surgery performed using a minimally invasive method through a small thoracotomy in the left chest with off-pump, anaortic, and all-arterial grafts (Minimally Invasive Off-Pump Anaortic Coronary Artery Bypass [MACAB]). Patient data were collected and retrospectively analyzed. Eight series from the literature using the multivessel mini-OPCAB and MACAB technique were also evaluated.

RESULTS

Collectively, from the literature, 2729 patients underwent an average of 2.4 bypasses with an early mortality rate of 0.7% and a stroke rate of 0.16%. In our MACAB case series, 112 patients underwent an average of 2.9 bypasses with a mortality rate of 1.8% and a stroke rate of 0%.

CONCLUSION

MACAB can be performed safely by experienced surgeons and reduces neurological injury and surgical trauma and may be a good alternative for multivessel stenting. Simulation systems are essential for its dissemination, and teams dedicated to coronary surgery-with subspecialty expertise-are necessary to achieve good outcomes.

Influence of Mild Thyroid Dysfunction on Outcomes after Off-Pump Coronary Artery Bypass Surgery

We retrospectively evaluated the association between preoperative mild thyroid dysfunction (subclinical hypothyroidism [SCH] or low triiodothyronine [T3] syndrome) and outcomes in patients who underwent off-pump coronary surgery (OPCAB). Further, 800 patients (2015−2020) were divided into euthyroid, low T3, and SCH groups. The primary outcome assessed the association with composite endpoints (myocardial infarction, prolonged mechanical ventilation [>24 h], acute kidney injury, and 30-day/in-hospital mortality). The secondary outcome assessed the association with long-term mortality and 10% and 8% of the patients exhibited low T3 and SCH, respectively. Incidences of composite endpoints were significantly higher in the low T3 and SCH groups versus the euthyroid group (50.6%, 45.2%, 17.4%, respectively, p < 0.001). Multivariable regression analysis revealed chronic kidney disease, anemia, EuroSCORE, low T3, and SCH as independent risk factors of composite endpoints. The long-term mortality rate (median follow-up, 30 months) was higher in the low T3 and SCH groups than in the euthyroid group (9.6%, 11.3%, 2.4%, respectively, p < 0.001). In the absence of overt thyroid dysfunction, low T3 and SCH were associated with increased risk of adverse outcomes after OPCAB. Moreover, the adverse influences of low T3 and SCH seem to extend to long-term mortality, implying that routine thyroid function tests may enhance accurate risk stratification.

Ten-Year Outcomes of Off-Pump vs On-Pump Coronary Artery Bypass Grafting in the Department of Veterans Affairs: A Randomized Clinical Trial

IMPORTANCE

The long-term benefits of off-pump ("beating heart") vs on-pump coronary artery bypass grafting (CABG) remain controversial.

OBJECTIVE

To evaluate the 10-year outcomes and costs of off-pump vs on-pump CABG in the Department of Veterans Affairs (VA) Randomized On/Off Bypass (ROOBY) trial.

DESIGN, SETTING, AND PARTICIPANTS

From February 27, 2002, to May 7, 2007, 2203 veterans in the ROOBY trial were randomly assigned to off-pump or on-pump CABG procedures at 18 participating VA medical centers. Per protocol, the veterans were observed for 10 years; the 10-year, post-CABG clinical outcomes and costs were assessed via centralized abstraction of electronic medical records combined with merges to VA and non-VA databases. With the use of an intention-to-treat approach, analyses were performed from May 7, 2017, to December 9, 2021.

INTERVENTIONS

On-pump and off-pump CABG procedures.

MAIN OUTCOMES AND MEASURES

The 10-year coprimary end points included all-cause death and a composite end point identifying patients who had died or had undergone subsequent revascularization (ie, percutaneous coronary intervention [PCI] or repeated CABG); these 2 end points were measured dichotomously and as time-to-event variables (ie, time to death and time to composite end points). Secondary 10-year end points included PCIs, repeated CABG procedures, changes in cardiac symptoms, and 2018-adjusted VA estimated costs. Changes from baseline to 10 years in post-CABG, clinically relevant cardiac symptoms were evaluated for New York Heart Association functional class, Canadian Cardiovascular Society angina class, and atrial fibrillation. Outcome differences were adjudicated by an end points committee. Given that pre-CABG risks were balanced, the protocol-driven primary and secondary hypotheses directly compared 10-year treatment-related effects.

RESULTS

A total of 1104 patients (1097 men [99.4%]; mean [SD] age, 63.0 [8.5] years) were enrolled in the off-pump group, and 1099 patients (1092 men [99.5%]; mean [SD] age, 62.5 [8.5] years) were enrolled in the on-pump group. The 10-year death rates were 34.2% (n = 378) for the off-pump group and 31.1% (n = 342) for the on-pump group (relative risk, 1.05; 95% CI, 0.99-1.11; P = .12). The median time to composite end point for the off-pump group (4.6 years; IQR, 1.4-7.5 years) was approximately 4.3 months shorter than that for the on-pump group (5.0 years; IQR, 1.8-7.9 years; P = .03). No significant 10-year treatment-related differences were documented for any other primary or secondary end points. After the removal of conversions, sensitivity analyses reconfirmed these findings.

CONCLUSIONS AND RELEVANCE

No off-pump CABG advantages were found for 10-year death or revascularization end points; the time to composite end point was lower in the off-pump group than in the on-pump group. For veterans, in the absence of on-pump contraindications, a case cannot be made for supplanting the traditional on-pump CABG technique with an off-pump approach.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT01924442.

Mid-term outcomes of off-pump versus on-pump coronary artery bypass graft surgery; statistical challenges in comparison

BACKGROUND

Despite several studies comparing off- and on-pump coronary artery bypass grafting (CABG), the effectiveness and outcomes of off-pump CABG still remain uncertain.

METHODS

In this registry-based study, we assessed 8163 patients who underwent isolated CABG between 2014 and 2016. Propensity score matching (PSM), inverse probability of weighting (IPW) and covariate adjustment were performed to correct for and minimize selection bias.

RESULTS

The overall mean age of the patients was 62 years, and 25.7% were women. Patients who underwent off-pump CABG had shorter length of hospitalization (p < 0.001), intubation time (p = 0.003) and length of ICU admission (p < 0.001). Off-pump CABG was associated with higher risk of 30-days mortality (OR: 1.7; 95% CI 1.09-2.65; p = 0.019) in unadjusted analysis. After covariate adjustment and matching (PSM and IPW), this difference was not statistically significant. After an average of 36.1 months follow-up, risk of MACCE and all-cause mortality didn't have significant differences in both surgical methods by adjusting with IPW (HR: 1.03; 95% CI 0.87-1.24; p = 0.714; HR: 0.91; 95% CI 0.73-1.14; p = 578, respectively).

CONCLUSION

Off-pump and on-pump techniques have similar 30-day mortality (adjusted, PSM and IPW). Off-pump surgery is probably more cost-effective in short term; however, mid-term survival and MACCE trends in both surgical methods are comparable.

Long-Term Survival After On-Pump and Off-Pump Coronary Artery Bypass Grafting

BACKGROUND

Off-pump coronary artery bypass grafting (CABG) may be associated with increased hazard for long-term mortality as compared to on-pump CABG. We sought to evaluate risk-adjusted long-term survival after off-pump and on-pump CABG, particularly among high-volume and low-volume CABG surgeons.

METHODS

We evaluated 1,235,089 isolated CABGs (off-pump = 209,085; on-pump = 1,026,004) performed in Medicare beneficiaries from 2001-2015. Long-term hazard for mortality after off-pump versus on-pump CABG was compared with Kaplan-Meier and log-rank analysis among all CABG surgeons as well as high-volume and low-volume CABG surgeons, before and after inverse-probability of treatment weighting (IPTW) to adjust for confounding.

RESULTS

Among all surgeons, off-pump CABG was associated with a statistically-significant hazard for mortality as compared to on-pump CABG before and after IPTW (median survival: off-pump 9.8 years vs on-pump 10.2 years; difference in median survival -134 days; log-rank p<0.001). Cox regression analysis confirmed an interaction between surgeon volume and long-term mortality. The hazard for mortality associated with off-pump CABG was decreased among high-volume surgeons (difference in median survival: -84 days; log-rank p<0.001) and increased among low-volume surgeons (difference in median survival: -240 days; long-rank p<0.001).

CONCLUSIONS

Off-pump CABG was associated with a significant, but clinically modest, increased hazard for mortality as compared to on-pump CABG. The hazard was reduced when off-pump CABG was performed by high-volume CABG surgeons.

Real-World Outcomes of On- vs Off-Pump Coronary Bypass Surgery: Result from Korean Nationwide Cohort

BACKGROUND

While several randomized trials have shown conflicting results regarding the comparative effectiveness of on- and off-pump coronary arterial bypass grafting (CABG), research on long-term outcomes in large-scale, real-world clinical settings are limited. We sought to examine the comparative effectiveness of on- and off-pump CABG in a real-world clinical setting.

METHODS

Using the nationwide claims database of the Korean National Health Insurance Service, we identified patients who underwent isolated CABG from 2004 to 2013. Propensity-score matching with multivariable adjustment was used to assemble a cohort of patients with similar baseline characteristics.

RESULTS

Among 23,828 patients, 12,639 in the off-pump (53.0%) and 11,189 in the on-pump (47.0%) groups were enrolled. After matching, 6,483 pairs were included in the final analysis. At 30 days, there was no significant difference in adjusted mortality between the off- and on-pump groups (hazard ratio [HR], 1.00; 95% confidence interval [CI], 0.87-1.16). During long-term follow-up (100% complete; median 5.3yrs, maximum 13.2yrs), however, off-pump CABG was associated with a higher risk of mortality than on-pump CABG (HR, 1.09; 95% CI, 1.03-1.15). The risks of myocardial infarction (MI) (HR, 1.3; 95% CI, 1.16-1.45) and repeat revascularization (HR, 1.50; 95% CI, 1.37-1.63) were also significantly higher in the off-pump CABG group than in the on-pump CABG group, while the stroke risk was similar inter-groups (HR, 0.99; 95% CI, 0.87-1.13).

CONCLUSIONS

In this contemporary, nationwide, clinical practice claim registry, off-pump CABG was associated with higher long-term risks of mortality, MI, and repeat revascularization than on-pump CABG.

Challenges in Patient Blood Management for Cardiac Surgery: A Narrative Review

About 15 years ago, Patient Blood Management (PBM) emerged as a new paradigm in perioperative medicine and rapidly found support of all major medical societies and government bodies. Blood products are precious, scarce and expensive and their use is frequently associated with adverse short- and long-term outcomes. Recommendations and guidelines on the topic are published in an increasing rate. The concept aims at using an evidence-based approach to rationalize transfusion practices by optimizing the patient's red blood cell mass in the pre-, intra- and postoperative periods. However, elegant as a concept, the implementation of a PBM program on an institutional level or even in a single surgical discipline like cardiac surgery, can be easier said than done. Many barriers, such as dogmatic ideas, logistics and lack of support from the medical and administrative departments need to be overcome and each center must find solutions to their specific problems. In this paper we present a narrative overview of the challenges and updated recommendations for the implementation of a PBM program in cardiac surgery.

On-Pump Beating Heart versus Off-Pump Coronary Artery Bypass Graft Surgery: Short-Term Follow-up Outcomes of a Single Center

Background and Aim: Novel surgical approaches are gaining attention in an attempt to overcome possible adverse events following coronary artery bypass graft (CABG) surgery. This single-center study aimed to evaluate and compare the early postoperative outcomes of on-pump beating-heart (OPBH-CABG) versus off-pump CABG surgery in similar risk groups with a total number of 1–2 grafts.

Methods: The records of a total of 229 patients who underwent non-emergency, primary, isolated, either OPBH-CABG (n = 32) or off-pump CABG (n = 197) surgery were retrospectively evaluated. Reported outcome measures included baseline data, the number of coronary artery grafts, prophylactic intra-aortic balloon pump, time of extubation from mechanical ventilation, duration of stay in the coronary ICU and hospital, as well as early postoperative complications, in-hospital and early postoperative mortality.

Results: The groups were identical with regards to age and BMI. The patients in the off-pump group received a higher number of grafts (1.84 ± 0.36 vs. 1.18 ± 0.39, p <0.0001). The OPBH-CABG group had a higher Euroscore II score (2.514 ± 1.68 vs. 1.706 ± 1.93, p = 0.021). The time to extubation after the surgery, postoperative length of ICU stay, and total length of hospital stay were similar between the groups (p = 0.2228; p = 0.098; p = 0.717, respectively). The incidence of arrythmia and atrial fibrillation was higher in the on-pump group (12.5% vs. 2.53%, p <0.05). One patient in the on-pump, and four patients in the off-pump groups deceased due to postoperative complications.

Conclusions: OPBH-CABG surgery is comparable to off-pump CABG in terms of early postoperative outcomes. In patients who underwent OPBH-CABG, the risk of arrythmia and atrial fibrillation should be of concern and solved with optimal strategies.

Minimally invasive and robotic coronary artery bypass grafting-a 25-year review

During the mid-1990s cardiac surgery started exploring minimally invasive methods for coronary artery bypass grafting (CABG) and has over a 25-year period developed highly differentiated and less traumatic operations. Instead of the traditional sternotomy mini-incisions on the chest or ports are placed, surgery on the beating heart is applied, sophisticated remote access heart lung machine systems as well as videoscopic units are available, and robotic technology enables completely endoscopic approaches. This review describes these methods, reports on the cumulative intra- and postoperative outcome of these procedures, and gives an integrated view on what less invasive coronary bypass surgery can achieve. A total of 74 patient series published on the topic between 1996 and 2019 were reviewed. Six main versions of minimal access and robotically assisted CABG were applied in 11,135 patients. On average 1.3±0.6 grafts were placed and the operative time was 3 hours 42 min ± 1 hour 15 min. The procedures were carried out with a hospital mortality of 1.0% and a stroke rate of 0.6%. The revision rate for bleeding was 2.5% and a renal failure rate of 0.9% was noted. Wound infections occurred at a rate of 1.2% and postoperative hospital stay was 5.6±2.2 days. It can be concluded that less invasive and robotically assisted versions of coronary bypass grafting are carried out with an adequate safety level while surgical trauma is significantly reduced.

In situ skeletonized bilateral thoracic artery for left coronary circulation: a 20-year experience

OBJECTIVES

Our goal was to analyse the outcomes in a patient population using a standardized technique for coronary artery bypass grafting (CABG) consisting of total arterial myocardial revascularization utilizing the in situ skeletonized bilateral thoracic artery for left coronary circulation. We also explored potential predictors of long-time unfavourable outcomes.

METHODS

Patients undergoing total arterial myocardial revascularization using in situ skeletonized bilateral thoracic artery for left coronary circulation between January 1997 and May 2017 were included prospectively in this study. The median follow-up (100% complete) was 103 months (interquartile range 61-189 months) and ranged from 1 to 245 months.

RESULTS

A total of 1325 consecutive patients were recruited. During the follow-up period, there were 131 deaths (9.8%), 146 repeat revascularizations (11.0%) and 229 major adverse cardiac events (17.2%). The 18-year freedom from major adverse cardiac events was 62.6 ± 9.3%, 62.5 ± 6.3% and 53.9 ± 11.0%, respectively. Multivariable models showed that a left ventricular ejection fraction ≤35%, chronic obstructive pulmonary disease, peripheral vascular disease (P < 0.001), chronic kidney disease and age ≥80 years (P = 0.002) were independent predictors of diminished long-term survival. Moreover, peripheral vascular disease and off-pump coronary artery bypass (both, P < 0.001) predicted repeat revascularization. Finally, age ≥80 years, peripheral vascular disease, left ventricular ejection fraction ≤35%, off-pump coronary artery bypass and chronic pulmonary obstructive disease were independent predictors of major adverse cardiac events during the long-term follow-up period (all, P < 0.001).

CONCLUSIONS

Coronary artery bypass using the in situ skeletonized bilateral thoracic artery for left coronary circulation configuration for total arterial myocardial revascularization resulted in satisfactory long-term results with a low incidence of death and late events and may represent a technique of choice in selected patients having CABG. Larger and long-term prospective studies are, however, warranted.

Consensus Report on Patient Blood Management in Cardiac Surgery by Turkish Society of Cardiovascular Surgery (TSCVS), Turkish Society of Cardiology (TSC), and Society of Cardio-Vascular-Thoracic Anaesthesia and Intensive Care (SCTAIC)

Anemia, transfusion and bleeding independently increase the risk of complications and mortality in cardiac surgery. The main goals of patient blood management are to treat anemia, prevent bleeding, and optimize the use of blood products during the perioperative period. The benefit of this program has been confirmed in many studies and its utilization is strongly recommended by professional organizations. This consensus report has been prepared by the authors who are the task members appointed by the Turkish Society of Cardiovascular Surgery, Turkish Society of Cardiology (TSC), and Society of Cardio-Vascular-Thoracic Anaesthesia and Intensive Care to raise the awareness of patient blood management. This report aims to summarize recommendations for all perioperative blood- conserving strategies in cardiac surgery.

Current Readings on Outcomes After Off-Pump Coronary Artery Bypass Grafting

Off-pump coronary artery bypass grafting (CABG) gained popularity in the 1990s through early 2000s as surgeons sought to mitigate the purported adverse effects of cardiopulmonary bypass and reduce the risk of neurologic events from aortic manipulation. Since then, results of several large randomized controlled trials and meta-analyses have failed to demonstrate an advantage of off-pump CABG over traditional on-pump CABG and have even raised concerns about potential suboptimal outcomes. The modern debate about off- vs on-pump CABG centers around long-term outcomes, the role of surgeon experience, identification of specific patient populations for which off-pump CABG is most appropriate, and identification of novel techniques and technologies to improve long-term outcomes. We review the key findings of 5 contemporary papers that address these issues and provide a current perspective on the status of off-pump CABG.

Long-Term Survival Following Off-Pump Coronary Surgery: Does Surgeon Experience Make a Difference?

See Article by Gaudino et al .

Perioperative safety in coronary artery bypass grafting: the role of the anesthesiologist

PURPOSE OF REVIEW

As our population ages and cardiovascular disease increases in prevalence, a growing number of patients will be candidates for coronary artery bypass grafting (CABG). Outcomes from this common surgery can be improved by a coordinated team approach involving physicians, nurses, and healthcare professionals from multiple specialties. This review will discuss the role cardiovascular anesthesiologists play in the perioperative care of these complex patients.

RECENT FINDINGS

Cardiovascular anesthesiologists may play a variety of important roles throughout the entire perioperative period of patients undergoing CABG. This may include identification and optimization of preoperative comorbidities, employment of enhanced recovery pathways, perioperative echocardiographic assessment of complex cardiovascular states, management of patients on cardiopulmonary bypass, and others. There is growing evidence that each of these areas contributes to better care and improved outcomes.

SUMMARY

Care of the patient undergoing CABG requires a team approach. Optimal team dynamics translate into better care for patients and improved outcomes. The cardiovascular anesthesiologist is an integral member of this team whose role is central in the coordination of all aspects of perioperative care. Preoperative optimization begins the process, which continues throughout surgery, cardiopulmonary bypass, and into the postoperative period.

Bilateral internal thoracic arteries: what is the State of the ART?

PURPOSE OF REVIEW

To provide a broad overview of the current state of knowledge of coronary artery bypass grafting with bilateral internal thoracic artery (BITA).

RECENT FINDINGS

There exists a large body of literature from mostly observational studies supporting the use of BITA in patients undergoing coronary artery bypass grafting but selection bias is a major issue with nonrandomized data. The precise method of BITA use does not appear to impact graft patency nor clinical outcomes - in other words, BITA in any configuration appears to be protective. The major downside is the increased risk of sternal complications, which can be mitigated with sternal-sparring adjuncts. The 5-year interim results of the landmark Arterial Revascularization Trial comparing BITA versus single internal thoracic artery did not show a clinical benefit for BITA but the end-of-trial results are pending. Despite wide guideline support for BITA use, uptake in the surgical community remains low and this is likely because of technical and institutional barriers.

SUMMARY

The published literature thus far supports surgical revascularization with BITA and we eagerly await the 10-year Arterial Revascularization Trial results. The general consensus is that a greater proportion of surgical revascularization should be performed using BITA.

Systematic review and meta-analysis in cardiac surgery: a primer

PURPOSE OF REVIEW

The purpose of this article is to review the strengths and weaknesses of systematic reviews and meta-analyses to inform our current understanding of cardiac surgery.

RECENT FINDINGS

A systematic review and meta-analysis of a focused topic can provide a quantitative estimate for the effect of a treatment intervention or exposure. In cardiac surgery, observational studies and small, single-center prospective trials provide most of the clinical outcomes that form the evidence base for patient management and guideline recommendations. As such, meta-analyses can be particularly valuable in synthesizing the literature for a particular focused surgical question. Since the year 2000, there are over 800 meta-analysis-related publications in our field. There are some limitations to this technique, including clinical, methodological and statistical heterogeneity, among other challenges. Despite these caveats, results of meta-analyses have been useful in forming treatment recommendations or in providing guidance in the design of future clinical trials.

SUMMARY

There is a growing number of meta-analyses in the field of cardiac surgery. Knowledge translation via meta-analyses will continue to guide and inform cardiac surgical practice and our practice guidelines.

Clampless versus clamped coronary bypass grafting: does it make a difference?

PURPOSE OF REVIEW

The techniques of coronary artery bypass grafting (CABG) have evolved remarkably over the last two decades since the introduction of off-pump coronary artery bypass (OPCAB). This article focuses on the clinical outcomes of 'clampless' CABG strategies, that include OPCAB with a partial clamp, OPCAB with a proximal suture device, and aorta no-touch OPCAB.

RECENT FINDINGS

Observational studies have shown the superiority of OPCAB for preventing strokes and pulmonary complications. Conversely, recent large-scale randomized controlled trials (RCTs) have been unable to demonstrate the benefits of OPCAB. Because of these differing results across numerous studies, the debate about the overall superiority of OPCAB versus on-pump CABG remains controversial. However, the literature regarding the OPCAB technique with minimized manipulation of the aorta suggests this has likely benefits, especially for high-risk patients.

SUMMARY

Previous large RCTs did not focus on specific approaches of OPCAB or the importance of the experience of surgeons and institutions, and so further studies are needed. Observational studies and meta-analyses have indicated that improved outcomes can be achieved by applying specific OPCAB approaches according to each patient's characteristics.

Right atrium positioning for exposure of right pulmonary veins during off-pump atrial fibrillation ablation

OBJECTIVES

Concomitant surgical ablation of atrial fibrillation (AF) is recommended for patients undergoing off-pump coronary revascularization in the presence of this arrhythmia. Achievement of optimal visualization of pulmonary veins while maintaining stable haemodynamic conditions is crucial for proper completion of the ablation procedure. This study evaluates the safety and feasibility of right atrial positioning using a suction-based cardiac positioner as opposed to compressive manoeuvres for exposure during off-pump surgical ablation for AF.

METHODS

Thirty-four consecutive patients underwent pulmonary vein isolation, ganglionated plexi ablation and left atrial appendage occlusion during off-pump coronary artery bypass grafting. Right atrial suction positioning was used to visualize right pulmonary veins. Safety and feasibility end points were analysed intraoperatively and in the early postoperative course.

RESULTS

In all patients, right atrial positioning created optimal conditions to complete transverse and oblique sinus blunt dissection, correct placement of a bipolar ablation probe, detection and ablation of ganglionated plexi and conduction block assessment. In all patients, this entire right-sided ablation procedure was completed with a single exposure manoeuvre. Feasibility end points were achieved in all study patients.

CONCLUSIONS

This report documents the safety and feasibility of right atrial exposure using a suction-based cardiac positioner to complete ablation for AF concomitant with off-pump coronary revascularization. This technique may be widely adopted to create stable haemodynamic conditions and optimal visualization of the right pulmonary veins.

Minimally invasive coronary artery bypass grafting: a systematic review

To minimize surgical morbidity in coronary artery bypass grafting, minimally invasive cardiac surgery has gained popularity. Minimally invasive coronary artery bypass grafting offers unique advantages compared to conventional off-pump coronary artery bypass or minimally invasive direct coronary artery bypass in that it enables the surgeon to harvest and graft bilateral internal thoracic arteries via a small thoracotomy while being conducted completely off-pump. This review focuses on current evidence behind off-pump coronary artery bypass, multi-arterial revascularization, patient populations that would most benefit from bilateral internal thoracic artery minimally invasive coronary artery bypass grafting, the surgical technique, and early outcomes. By overcoming the perceived inability to utilize bilateral internal thoracic arteries in minimally invasive coronary artery bypass grafting, the new technique further expands the armamentarium of surgeons and cardiologists. Hybrid coronary revascularization with bilateral internal thoracic artery minimally invasive coronary artery bypass grafting further augments the appeal of the next generation of minimally invasive cardiac surgery.

A systematic review and meta-analysis of in situ versus composite bilateral internal thoracic artery grafting

OBJECTIVES

This meta-analysis examines whether there is any advantage of coronary artery bypass graft with bilateral internal thoracic artery (BITA) as an in situ versus composite graft.

METHODS

We searched MEDLINE and EMBASE Databases from 1996 to 2016 for studies that compared coronary artery bypass graft with BITA as in situ versus composite graft. Data were extracted by 2 independent investigators and meta-analyzed with the use of random effects.

RESULTS

Two randomized controlled trials (RCTs; n = 705), 2 matched (n = 1688), and 4 unadjusted observational studies (n = 3517) met inclusion criteria. Composite grafting trended towards greater distal anastomoses (+0.22, 95% confidence interval, -0.01 to +0.45 anastomoses/patient; P = .06 [4 unadjusted observational studies]) and greater distal anastomoses using an internal thoracic artery (+0.80, 95% confidence interval, 0.41-1.18 anastomoses/patient; P < .001 [1 RCT]). There were no differences in perioperative or longer-term composite cardiovascular outcomes comparing in situ versus composite BITA or individual outcomes of mortality, repeat revascularization, myocardial infarction, and cardiovascular mortality. Pooled results differed by study type with pooled results from lower-risk-of-bias RCTs typically showing increases in events rates, and pooled results from higher-risk-of-bias unadjusted observational studies typically showing decreases in event rates of in situ versus composite BITA. Post hoc subgroup analysis suggested possible improvements in all-cause mortality and revascularization for in situ BITA in studies with short-term (<5 years) versus longer-term follow-up, regardless of study type.

CONCLUSIONS

Our meta-analysis found that use of BITA as a composite graft configuration facilitated greater internal thoracic artery revascularization but both grafting strategies offer similar clinical outcomes. Our study supports the use of in situ and composite BITA for select patients but high-quality, long-term prospective trials are needed.

Hospital-Based HTA and Know4Go at MEDICI in London, Ontario, Canada

The majority of healthcare in Canada is universally provided and publicly funded through the provincial government.