“Anaortic” Off-Pump Coronary Artery Bypass Grafting Significantly Reduces Neurological Complications Compared to Off-Pump and Conventional On-Pump Surgery with Aortic Manipulation

Off-Pump Coronary Artery Bypass Grafting Surgery: A Valuable 2-Day Experience

Currently, coronary artery disease (CAD) has been identified as the leading cause of mortality in Malaysia and in other countries worldwide. Genetic predisposition and comorbidities such as hypertension and diabetes mellitus, gender, lifestyle, and several other risk factors can contribute to the development of CAD. Pharmacological and surgical treatments play a vital role in improving the quality of life of patients with CAD. New surgical techniques and continuous interventions have been introduced to improve the treatment outcome. Recently, cardiothoracic teams from Universiti Teknologi MARA (UiTM) and Universiti Sains Malaysia (USM) have conducted a 2-day live workshop on off-pump coronary artery bypass (OPCAB) surgery. In this brief communication, we share the highlights and clinical tips of the OPCAB surgery gained from the collaboration.

Survival benefit from a second arterial conduit to the circumflex circulation persists in elderly after coronary artery bypass surgery

BACKGROUND

This retrospective propensity matched study investigated the impact of age on the survival benefit from a second arterial conduit to the left-sided circulation.

METHODS

Data for isolated coronary artery bypass surgery were collected from October 2004 to March 2014. All patients with an internal mammary artery graft to left anterior descending artery and additional arterial or venous graft to the circumflex circulation were included. Propensity matching was used to balance co-variates and generate odds of death for each observation. Odds ratios (venous vs. arterial) were charted against age.

RESULTS

The in-hospital mortality rate was 1.12% (arterial) vs. 1.24% (venous) (p = 0.77). The overall 10-year survival was 74.6% (venous) vs. 82.6% (arterial) (p = 0.001). A total of 1226 patients were successfully matched to the venous or arterial (second conduit to circumflex territory after left internal mammary artery to left anterior descending artery) cohorts. Odds ratio for death (venous to arterial) showed a linear decremental overall survival benefit for the second arterial graft to circumflex circulation with increasing age.

CONCLUSIONS

The survival benefit of a second arterial graft persists through all age groups with a gradual decline with increasing age over the decades. Elderly patients should not be denied a second arterial graft to the circumflex circulation based on age criterion alone.

Total arterial off-pump coronary revascularization: The Holy Grail?

PURPOSE OF REVIEW

Coronary artery bypass grafting (CABG) remains the standard of care for patients with complex multivessel coronary artery disease. However, conventional CABG utilizing left internal mammary artery and supplemental vein grafts performed on cardiopulmonary bypass is marred by questionable long-term patency of vein grafts and risk of neurological injury. Total arterial off-pump CABG is a strategy associated with avoidance of neurological injury and vein graft failure. The aim of this review is to summarize recent evidence on safety and effectiveness of total arterial off-pump CABG.

RECENT FINDINGS

Two key studies have been published recently. One describes a dual inflow technique that achieves anaortic, off-pump complete revascularization using arterial grafts only. The other is single centre study that reports 10-year survival of 89.33%, rate of freedom from repeat revascularization of 91.33% and early stroke rate of 0.9% after total arterial off-pump CABG.

SUMMARY

Total arterial off-pump CABG with its advantages of improved survival, enhanced freedom from repeat revascularization and low stroke rate can be regarded as the Holy Grail of myocardial revascularization. However, the results of a large, multicenter, prospective trial are required to substantiate this status.

Anaortic coronary surgery using the Π-circuit is associated with a low incidence of perioperative neurological complications

OBJECTIVES

Our goal was to compare the observed and the expected rates of postoperative cerebrovascular accidents (CVA) in a large cohort of consecutive patients undergoing off-pump coronary artery bypass grafting (CABG) using the ∏-circuit as a no-touch technique.

METHODS

From January 2001 to May 2016, 3081 patients were consecutively submitted to an off-pump CABG operation using the ∏-circuit. A CVA was defined as a neurological deficit, lasting less (transient ischaemic attack) or more (stroke) than 24 h, diagnosed by a neurologist and confirmed by a computed tomography or magnetic resonance imaging scan of the brain. The primary end point was to compare the observed and the expected rates of CVAs; the latter was obtained using the Society of Thoracic Surgeons' calculator. The secondary end point was to compare the observed and the expected mortality rates using the Society of Thoracic Surgeons' calculator and the prevalence of postoperative complications. Moreover, we identified some subgroups at higher risk.

RESULTS

The postoperative rate of CVAs was 0.5% (14 cases): 2 (0.1%) were transient ischaemic attacks and 12 (0.4%) were strokes. The mean expected CVA rate (1.6%) was significantly higher than the observed rate (P < 0.001). None of patients who experienced postoperative CVAs died. The observed mortality was 1.3% (40 patients) vs the expected mortality (2.6%), which was significantly higher (P < 0.001). Multivariable analysis identified age >70 years old, diabetes, extracardiac vasculopathy and chronic renal failure as risk factors for postoperative CVAs. However, in all the subgroups of risk, except for those with chronic renal failure, the use of the ∏-circuit was associated with a low rate of CVAs.

CONCLUSIONS

The ∏-circuit should be included as a possible choice among no-touch techniques. The observed rate of CVAs of 75% is lower than the expected rate.

Minimally invasive direct coronary bypass surgery via distal mini-sternotomy : Promising clinical results with anaortic, multivessel, all-arterial technique

BACKGROUND

Minimally invasive direct coronary artery bypass grafting (MIDCAB) was developed to decrease perioperative morbidity, some of which may be related to the use of cardiopulmonary bypass and to cross-clamping of the aorta. We report our initial experience with multivessel MIDCAB via distal mini-sternotomy (DIMS). DIMS is performed to gain access to the left and right internal thoracic arteries and to reach the left anterior descending coronary artery (LAD), diagonal branches, and right coronary artery (RCA).

METHODS

Between January 2016 and January 2017, 12 patients with significant coronary artery disease of the LAD and the RCA underwent multivessel, all-arterial MIDCAB through a distal midline skin incision from the fourth intercostal space to the xyphoid process, with L‑ or T‑shaped division of the sternum. The mean age of the patients was 61.5 ± 5.2 years (range: 52-71 years).

RESULTS

We performed all-arterial revascularization using the left internal mammary artery in 12 patients, the radial artery in ten, and the right internal mammary artery in two patients. The mean number of grafts per patient was 2.08 ± 0.4 (range: 2-3). The mean length of the skin incision was 8.5 ± 1.3 cm (range: 7-11 cm). There was no perioperative ischemia, postoperative bleeding, or arrhythmia events. No postoperative cognitive dysfunction occurred. The mean hospital stay was 5.6 days. No major adverse cardiac events (MACE) occurred at the 12-month follow-up. At follow-up, all patients were in New York Heart Association class I and there were no wound complications.

CONCLUSION

Although MIDCAB-DIMS is technically more demanding than conventional procedures and our experience is limited, we conclude that this technique can be used safely in selected patients, with promising 12-month follow-up results.

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.

Coronary Artery Bypass Grafting With and Without Manipulation of the Ascending Aorta: A Network Meta-Analysis

BACKGROUND

Coronary artery bypass grafting (CABG) remains the standard of treatment for 3-vessel and left main coronary disease, but is associated with an increased risk of post-operative stroke compared to percutaneous coronary intervention. It has been suggested that CABG techniques that eliminate cardiopulmonary bypass and reduce aortic manipulation may reduce the incidence of post-operative stroke.

OBJECTIVES

A network meta-analysis was performed to compare post-operative outcomes between all CABG techniques, including anaortic off-pump CABG (anOPCABG), off-pump with the clampless Heartstring device (OPCABG-HS), off-pump with a partial clamp (OPCABG-PC), and traditional on-pump CABG with aortic cross-clamping.

METHODS

A systematic search of 6 electronic databases was performed to identify all publications reporting the outcomes of the included operations. Studies reporting the primary endpoint, 30-day post-operative stroke rate, were included in a Bayesian network meta-analysis.

RESULTS

There were 13 included studies with 37,720 patients. At baseline, anOPCABG patients had higher previous stroke than did the OPCABG-PC (7.4% vs. 6.5%; p = 0.02) and CABG (7.4% vs. 3.2%; p = 0.001) patients. AnOPCABG was the most effective treatment for decreasing the risk of post-operative stroke (-78% vs. CABG, 95% confidence interval [CI]: 0.14 to 0.33; -66% vs. OPCABG-PC, 95% CI: 0.22 to 0.52; -52% vs. OPCABG-HS, 95% CI: 0.27 to 0.86), mortality (-50% vs. CABG, 95% CI: 0.35 to 0.70; -40% vs. OPCABG-HS, 95% CI: 0.38 to 0.94), renal failure (-53% vs. CABG, 95% CI: 0.31 to 0.68), bleeding complications (-48% vs. OPCABG-HS, 95% CI: 0.31 to 0.87; -36% vs. CABG, 95% CI: 0.42 to 0.95), atrial fibrillation (-34% vs. OPCABG-HS, 95% CI: 0.49 to 0.89; -29% vs. CABG, 95% CI: 0.55 to 0.87; -20% vs. OPCABG-PC, 95% CI: 0.68 to 0.97), and shortening the length of intensive care unit stay (-13.3 h; 95% CI: -19.32 to -7.26; p < 0.0001).

CONCLUSIONS

Avoidance of aortic manipulation in anOPCABG may decrease the risk of post-operative stroke, especially in patients with higher stroke risk. In addition, the elimination of cardiopulmonary bypass may reduce the risk of short-term mortality, renal failure, atrial fibrillation, bleeding, and length of intensive care unit stay.

Off-pump coronary artery bypass grafting (OPCABG)-a 'personal' European perspective

Although popularised over two decades ago off-pump coronary artery bypass grafting (OPCABG) has seen a decrease in utilisation especially over the last decade. This has been due to publication of a number of trials which suggested inferior outcomes with OPCABG. However, the validity of the findings in these trials has been questioned on the basis of doubts over operator experience as witnessed by large numbers of cross-overs. Two more recent large randomised trials have shown very similar outcomes between on and off-pump surgery up to 1- and 5-year outcomes are imminently due. Furthermore several meta-analyses have reported that OPCABG reduces mortality, myocardial infarction and major morbidity in higher risk patients. Consequently there is a clear rationale for OPCABG in certain cohorts of patients and especially when combined with a no touch aortic technique in those with significant disease of the ascending aorta. The article discusses the importance of routine performance of OPCABG if it is to produce high quality results and especially in higher risk patients.

Cerebrovascular Events After No-Touch Off-Pump Coronary Artery Bypass Grafting, Conventional Side-Clamp Off-Pump Coronary Artery Bypass, and Proximal Anastomotic Devices: A Meta-Analysis

Background

Off‐pump coronary artery bypass (OPCAB) has been shown to reduce the risk of neurologic complications as compared to coronary artery bypass grafting performed with cardiopulmonary bypass. Side‐clamping of the aorta while constructing proximal anastomoses, however, still carries substantial risk of cerebral embolization. We aimed to perform a comprehensive meta‐analysis of studies assessing 2 clampless techniques: aortic “no‐touch” and proximal anastomosis devices (PAD) for OPCAB.

Methods and Results

PubMed, CINAHL, CENTRAL, and Google Scholar databases were screened for randomized controlled trials and observational studies comparing “no‐touch” and/or PAD with side‐clamp OPCAB and reporting short‐term (≤30 days) outcomes: cerebrovascular accident and all‐cause mortality. A total of 18 studies (3 randomized controlled trials) enrolling 25 163 patients were included. Aortic “no‐touch” was associated with statistically lower risk of cerebrovascular accident as compared to side‐clamp OPCAB: risk ratio 95% CI: 0.41 (0.27–0.61); P<0.01; I²=0%. Event rates were 0.36% and 1.28% for “no‐touch” and side‐clamp OPCAB, respectively. No difference was seen between PAD and side‐clamp OPCAB: 0.71 (0.33–1.55); P=0.39; I²=39%. A trend towards increased 30‐day all‐cause mortality with PAD and no difference with “no‐touch” were observed when compared to side‐clamp OPCAB. In a subset analysis, “no‐touch” consistently reduced the risk of cerebrovascular accident regardless of patients’ baseline risk characteristics. A benefit with PAD was observed in low‐risk patients.

Conclusions

Aortic “no‐touch” technique was associated with nearly 60% lower risk of postoperative cerebrovascular events as compared to conventional side‐clamp OPCAB with effect consistent across patients at different risk.

Partially anaortic clampless off-pump coronary artery bypass prevents neurologic injury compared to on-pump coronary surgery: a propensity score-matched study on 286 patients

Anaortic coronary artery bypass proved to prevent early neurologic injury compared to on-pump CABG. The Cardica PAS-Port(®) is a fully automated device that might be able to perform proximal aorto-venous anastomoses without an increased embolic risk. We evaluated early post-operative neurologic outcome in a matched population following clampless OPCAB (CCAB: either "all-arterial" or with automatically anastomosed venous grafts) or on-pump CABG. 366 consecutive patients were submitted to isolated coronary bypass by a single surgeon experienced in both off and on-pump procedures between January 2009 and December 2013. Of these patients, 223 underwent a clampless off-pump revascularization. After propensity score matching, 143 pairs were selected, who received either off-pump or on-pump surgery. In the off-pump group, CCAB was performed with an all-arterial approach (n = 33) or with automated proximal anastomosis of the venous graft(s) by means of the Cardica PAS-Port(®) connector (n = 110). Neurologic injury was defined as non-reversible (NRNI: lethal coma or stroke) or reversible (RNI: TIA or delirium). Operative mortality was 2.4 % (CCAB 1.4 %; CABG 3.5 %; p = 0.14). The global rate of early neurologic injury was 5.6 % (CCAB 2.1 vs. CABG 9.1 %; p = 0.006). Incidence was 1.4 % for NRNI (CCAB 0 vs. CABG 2.8 %; p = 0.04) and 4.2 % for RNI (CCAB 2.1 vs. CABG 6.3 %; p = 0.06). No differences were found among other major perioperative outcomes. CCAB prevents both early post-operative RNI and NRNI. This result can be achieved with a totally anaortic strategy and also with the aid of a fully automated device for proximal aorto-venous anastomoses.

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.

Effects of on-pump and off-pump surgery in the Arterial Revascularization Trial

OBJECTIVES

The Arterial Revascularization Trial (ART) is a randomized comparison of bilateral internal mammary artery (BIMA) versus single internal mammary artery (SIMA) grafting in coronary artery bypass graft (CABG) surgery and is one of the largest randomized trials of surgery ever conducted. ART is also one of the largest studies of contemporary CABG with a high proportion of off-pump surgeries (41%). The objective of this post hoc analysis was to evaluate the surgical process and 1-year outcomes for surgery performed on-pump compared with off-pump.

METHODS

ART randomized 3102 patients with multivessel coronary artery disease (CAD) to SIMA or BIMA grafts to determine if BIMA grafts have an additional survival advantage at 10 years. The 1-year interim analysis showed an overall very low mortality and major morbidity rate irrespective of whether the procedure was with an SIMA or BIMA. The surgical process and 1-year outcomes were analysed according to whether surgery was performed on-pump or off-pump.

RESULTS

Baseline variables were not statistically significantly different between on- and off-pump surgery within each treatment group after taking account of the effects of clustering by individual surgeons. At both 30 days and 1 year, there was a low incidence of death (1.2%, 2.3%), stroke (1.1%, 1.7%), myocardial infarction (MI) (1.4%, 1.9%), repeat revascularization (0.5%, 1.5%) and wound reconstruction (1.2%). A similar average number of grafts were performed with on- and off-pump surgery (median = 3), but the duration of surgery was 20-30 min and ventilation time ∼ 2 h shorter with off-pump surgery. Blood loss and platelet transfusions were lower in the off-pump group, with no difference in the need for balloon pump or renal support. Sternal wound reconstruction was similar with off-pump surgery in the SIMA group (0.5 vs 0.6%) and lower with off-pump surgery in the BIMA group (1.4 vs 2.2%). Repeat revascularization was marginally higher in off-pump patients at 30 days (0.8 vs 0.3%) and at 1 year (1.7 vs 1.3%).

CONCLUSIONS

The outcomes of contemporary CABG are excellent with low mortality, stroke, myocardial infarction and need for wound reconstruction and repeat revascularization whether performed on-pump or off-pump.

CLINICAL TRIAL REGISTRATION

Controlled-trials.com (ISRCTN46552265).