Outcomes of 881 Consecutive Coronary Artery Bypass Graft Patients Using Heartstring Device

BACKGROUNDS

 One of the strategies to prevent stroke after coronary artery bypass grafting (CABG) may be the use of a device for proximal anastomosis without partial clamp of the ascending aorta.

METHODS

 We retrospectively investigated early and late outcomes in consecutive 881 patients undergoing isolated CABG using Heartstring for proximal anastomosis from January 2008 to December 2022, to reveal the validity to use it. All patients underwent preoperative imaging workups to evaluate neurovascular atherosclerosis.

RESULTS

 The mean age of the patients was 68.9 years, 20% were female and 13% had previous history of stroke. CABG was on-pump beating heart (52.2%) or off-pump (47.8%) with a mean number of distal anastomoses of 3.38 ± 0.93, using 1.62 ± 0.53 Heartstring devices under different aortic manipulations. In-hospital mortality was 2.0% and perioperative stroke rate was 0.9%, none of them died during hospital stay. During the follow-up period of 70 ± 47 months, the overall actuarial survival rates were 86 and 66%, and major adverse cardiac and cerebrovascular events (MACCEs)-free rates were 86 and 70% at 5 and 10 years, respectively. On multivariable analysis, risk factors for late death included male, previous history of stroke, postoperative sternomediastinitis, late new-onset stroke, and MACCEs, but did not include the perioperative stroke.

CONCLUSION

 Low stroke rate, as low as 0.9%, after CABG using Heartstring for proximal anastomosis, although under a variety of aortic manipulations, may contribute to the improved long-term prognosis.

Comparison between Off-Pump and On-Pump Beating Heart Coronary Artery Bypass Grafting

BACKGROUND

 Although coronary artery bypass grafting (CABG) is performed via three different techniques, conventional, on-pump beating heart CABG (ONBHCAB), or off-pump CABG (OPCAB), data are limited to compare ONBHCAB with OPCAB.

METHODS

 We retrospectively investigated the postoperative cardiac biomarkers, creatine kinase-MB (CK-MB), and troponin I (cTnI), and early and late outcomes in 806 patients undergoing isolated ONBHCAB or OPCAB between February 2008 and September 2022. To eliminate the bias between different groups, propensity score matching was conducted to validate the findings.

RESULTS

 After matching, the number of each study group totaled 270 patients. In both complete and matched cohorts, early outcomes, including morbidities and mortalities, were similar. However, cTnI and CK-MB levels were significantly higher after ONBHCAB than after OPCAB with median peak cTnI of 9.85 versus 4.60 ng/mL and median peak CK-MB of 48.45 versus 17.10 ng/mL in the matched cohort, which were quite low, below the threshold for values defining perioperative myocardial infarction. At follow-up of 73 ± 45 months, the overall actuarial survival rates were similar between the ONBHCAB and OPCAB patients (86 vs. 87% at 5 years and 64 vs. 68% at 10 years, respectively, in the matched cohort).

CONCLUSION

 ONBHCAB may be a comparable alternative to OPCAB with similar early and late outcomes, despite higher elevation of postoperative cardiac biomarkers. ONBHCAB provides more efficient hemodynamic support, providing a better surgical visual field, than OPCAB while reducing the risk of incomplete revascularization.

Comparative efficacy on outcomes of C-CABG, OPCAB, and ONBEAT in coronary heart disease: a systematic review and network meta-analysis of randomized controlled trials

IMPORTANCE

Coronary artery bypass grafting (CABG) remains the gold standard for the treatment of multivessel and left main coronary heart disease. However, the current evidence about the optimal surgical revascularization strategy is inconsistent and is not sufficient to allow for definite conclusions. Thus, this topic needs to be extensively discussed.

OBJECTIVE

The aim of this present study was to compare the clinical outcomes of off-pump CABG (OPCAB), conventional on-pump CABG (C-CABG), and on-pump beating heart (ONBEAT) CABG via an updated systematic review and network meta-analysis of randomized controlled trials.

DATA SOURCES

PubMed, Web of Science, and the Cochrane Central Registry were searched for relevant randomized controlled trials that were published in English before 1 December 2021.

STUDY SELECTION

Published trials that included patients who received OPCAB, C-CABG, and ONBEAT CABG were selected.

DATA EXTRACTION AND SYNTHESIS

Two authors independently screened the search results, assessed the full texts to identify eligible studies and the risk of bias of the included studies, and extracted data. All processes followed the Preferred Reporting Items for Systematic Review and Meta-analysis of Individual Participant Data.

MAIN OUTCOMES AND MEASURES

The primary outcome was postoperative mortality in patients who underwent C-CABG, OPCAB, or ONBEAT CABG. The secondary outcomes were postoperative myocardial infarction, stroke, and renal impairment in the three groups. The time point for analysis of outcomes was all time periods during the postoperative follow-up.

RESULTS

A total of 39 385 patients (83 496.2 person-years) in 65 studies who fulfilled the prespecified criteria were included. In the network meta-analysis, OPCAB was associated with an increase of 12% in the risk of all-cause mortality when compared with C-CABG [odds ratio (OR): 1.12; 95% CI: 1.04-1.21], a reduction of 49% in the risk of myocardial infarction when compared with ONBEAT (OR: 0.51; 95% CI: 0.26-0.99), a reduction of 16% in the risk of stroke when compared with C-CABG (OR: 0.84; 95% CI: 0.72-0.99) and a similar risk of renal impairment when compared with C-CABG and ONBEAT.

CONCLUSIONS AND RELEVANCE

OPCAB was associated with higher all-cause mortality but lower postoperative stroke compared with C-CABG. OPCAB was associated with a lower postoperative myocardial infarction than that of ONBEAT. Early mortality was comparable among OPCAB, ONBEAT, and C-CABG.

The outcomes of three different techniques of coronary artery bypass grafting: On-pump arrested heart, on-pump beating heart, and off-pump

OBJECTIVE

Conventional coronary artery bypass grafting (CABG) or on-pump arrested heart CABG (ONCAB) is a standard and simple technique. However, adverse effects can occur due to the use of aortic cross-clamp and cardiopulmonary bypass. Performing off-pump CABG (OPCAB) aims to avoid these adverse effects but may result in incomplete revascularization. On-pump beating heart CABG (ONBHCAB) combines the benefits of both ONCAB and OPCAB. This study focuses on comparing the short- and long-term outcomes of different CABG techniques.

METHOD

Retrospective observational cohort included 2,028 patients who underwent ONCAB, OPCAB, and ONBHCAB. The short-term outcomes including postoperative ischemic injury, hemodynamic functions, and adverse events were compared. The long-term outcomes were overall survival and the occurrence of major adverse cardiovascular events (MACE). Propensity score matching ensured comparability among the three patient groups.

RESULTS

After matching, there were no differences in baseline characteristics. Regarding ischemic injury, OPCAB showed the lowest peak cardiac enzyme levels (all p≤0.001). There were no statistically significant differences in the change of hemodynamic function (cardiac index) between the three groups (p = 0.158). Ten-year survival for OPCAB, ONBHCAB, and ONCAB were 80.5%, 75.9%, and 73.7%, respectively. OPCAB was associated with a significant reduction in mortality risk and MACE when compared to others (Mortality HR = 0.33, p = 0.001, MACE HR = 0.52, p = 0.004).

CONCLUSION

OPCAB implementation resulted in a lower occurrence of postoperative ischemic injury than ONCAB and ONBHCAB. No differences in postoperative hemodynamic function in all three techniques were observed. OPCAB respectively were preferable techniques beneficial for long-term outcomes.

Case report: Conquer a complex variant: Coronary-pulmonary artery fistulas, atrial septal defect and bicuspid pulmonary valve, under beating heart surgery

Coronary artery to pulmonary artery fistula (CPAF) is a congenital or acquired abnormal channel between arteries, with a left-to-right cardiac shunting, which may lead to myocardial ischemia, arrhythmia, thrombotic complications, and heart failure. CPAF is usually detected by coronary angiography but few reports have used beating-heart surgery as a detection method. The patient in this case report is a 39-year-old male diagnosed with atrial septal defect (ASD), bicuspid pulmonary valve, and moderate tricuspid regurgitation (TR). He is asymptomatic. In preoperative evaluation, significant CPAF was suspected using echocardiography. The patient refused coronary angiography due to allergic history. Therefore, the cardiac team designed and performed on-pump beating-heart surgery (OPBHS) to detect and repair these disorders, and suggested OPBHS as a myocardial protection strategy for the patient at low surgical risk. A rare and complex cardiovascular case with CPAFs from two branches of the left anterior descending coronary (LAD) artery to the main pulmonary artery (MPA) with ASD, bicuspid pulmonary valve, and moderate TR has not yet been reported in the literature, and its embryological hypothesis has been further analyzed in this report.

On-pump beating heart versus conventional on-pump coronary artery bypass grafting on clinical outcomes: a meta-analysis

Background

A hybrid surgery method, on-pump beating heart coronary artery bypass graft (ON-BH CABG), is supposed to be a promising technology for coronary artery revascularization. Here, we conducted a comprehensive meta-analysis of the data derived from published studies on ON-BH CABG and conventional on-pump coronary artery bypass graft (C-CABG) to compare their short-term and long-term clinical outcomes.

Methods

We searched major electronic databases and 24 studies incorporating 6,862 patients (1,847 ON-BH CABG and 5,015 C-CABG) were included eventually, and 9 studies of them were focusing on high-risk patients.

Results

Compared with ON-BH CABG, C-CABG was associated with a higher risk in early mortality [odds ratio (OR), 1.45; 95% confidence interval (CI), 1.09 to 1.93; P=0.01], myocardial infarction (MI) (OR, 2.60; 95% CI, 1.41 to 4.78; P<0.01), low output syndrome (LOS) (OR, 2.56; 95% CI, 1.55 to 4.23; P<0.01), renal failure (OR, 1.84; 95% CI, 1.38 to 2.44; P<0.01). In contrast, there was no significant difference in long-term survival [hazard ratio (HR), 1.08; 95% CI, 0.81 to 1.43; P=0.60]. In systematic analysis of the studies in high-risk patients, ON-BH CABG showed a lower risk in terms of early mortality, intra-aortic balloon pump (IABP) usage, renal failure, hemodialysis, MI and pulmonary complication. No significant difference was observed in the long-term survival between ON-BH CABG and C-CABG.

Conclusions

With experienced and adept surgical team and mature ON-BH technology, ON-BH CABG may reduce the risk of postoperative death and complications in some patients. It might be an attractive alternative for high-risk patient populations.

Beating-heart on-pump coronary artery bypass grafting vs. off-pump coronary artery bypass grafting: a systematic review and meta-analysis

Background

Beating-heart on-pump coronary artery bypass grafting (CABG), otherwise known as BH-ONCAB, can reduce myocardial injury by preserving native coronary blood flow while maintaining hemodynamic stability by the effective support of cardiopulmonary bypass (CPB). This study aimed to identify whether BH-ONCAB confers a survival, mortality, or morbidity benefit over off-pump CABG (OPCAB).

Methods

A systematic literature review identified 18 studies incorporating 5,615 patients (1,548 BH-ONCAB and 4,067 OPCAB cases) who satisfied the inclusion criteria. Outcome measures were meta-analyzed using random-effects modeling. Between-study heterogeneity was investigated through quality assessment and risk of bias analysis.

Results

The results demonstrated comparable early mortality and long-term survival between BH-ONCAB and OPCAB coronary revascularization with no significant statistical differences. The incidences of stroke, renal failure, blood loss, and arrhythmias were significantly higher in patients who underwent BH-ONCAB than patients who underwent OPCAB. However, BH-ONCAB conferred lower rates of incomplete revascularization and greater numbers of distal anastomoses.

Conclusions

BH-ONCAB is a safe and comparable alternative to OPCAB in terms of early mortality and late survival. BH-ONCAB may confer particular advantages in preventing incomplete revascularization and allowing more distal anastomoses compared to OPCAB. However, BH-ONCAB was associated with more postoperative complications due to the use of CPB. Future work should focus on larger matched studies and multicenter randomized controlled trials to optimize our surgical revascularization strategies.

Surgical Risk Factors for Ischemic Stroke Following Coronary Artery Bypass Grafting. A Multi-Factor Multimodel Analysis

Background: Ischemic stroke after coronary artery bypass (CABG) has been often linked to aortic manipulation during surgery. Objectives: The objective of the study was to estimate the rate of postoperative ischemic stroke within 30 days from CABG by surgical risk factors alone or in combination. Methods: The multinomial propensity score for multiple treatments was used to create six models with a total of 16,255 consecutive patients undergoing isolated CABG. For each model, a different classification variable was used to stratify patients. Results: Balance achieved in all models was substantial, enabling unbiased estimation of the treatment estimand. Both off-pump techniques with (0.009; 95% CI 0.006-0.011) or without proximal anastomoses (0.005; 0.005-0.003), and surgery performed on the beating heart using cardiopulmonary bypass with (0.009; 0.006-0.011) or without proximal anastomoses (0.024; 0.021-0.029) showed a mean stroke estimate significantly lower than the other techniques. Off-pump surgery and on-pump surgery without an aortic cross-clamp yielded nearly equal incidences of stroke (0.012; 0.008-0.015 and 0.018; 0.012-0.023, respectively). Using an aortic cross-clamp significantly increased the stroke estimate (0.075; 0.061-0.088), whereas using a side-biting clamp did not (0.039; 0.033-0.044). The number of aortic touches (0.029; 0.026-0.031) and the number of proximal anastomoses (0.044; 0.035-0.047) did not significantly increase the incidence of stroke. Conclusions: Aortic cross-clamping was found to be the primary cause of post-CABG ischemic stroke. Instead, additional aortic manipulation from a side-biting clamp, on-pump surgery, multiple aortic touches, number of proximal anastomoses, and aortic cannulation were found not to increase the estimate of stroke significantly. Further research on this topic is warranted.

Off-Pump Coronary Artery Bypass Reduces Cardiac Death in Patients with Peripheral Arteriopathy

OBJECTIVE

 The aim of this study was to investigate whether the use of off-pump coronary artery bypass (OPCAB) may enhance early outcomes in subjects with peripheral artery disease (PAD) undergoing coronary artery bypass grafting (CABG).

METHODS

 We employed a propensity-score (PS) method to compare early postoperative results of OPCAB and on-pump CABG patients with associated PAD. The study population consisted of 1,961 patients: 284 in the OPCAB and 1,677 in the on-pump CABG group. The inverse probability of treatment weighting was used as PS method.

RESULTS

 The incidence of death (1.2% [95% confidence interval, CI: -0.9 to 3.3%], p = 0.262), stroke (2.2% [95% CI: -1.4 to 5.7%], p = 0.235), acute kidney disease (1.5% [95% CI: -3.8 to 6.8%], p = 0.586), limb ischemia (3.2% [95% CI: -0.6 to 7.0%], p = 0.315), and low output syndrome (1.2% [95% CI: -0.9 to 3.3%], p = 0.262) did not differ between the two groups. On the other hand, the rate of cardiac death (1.2% [95% CI: -0.1 to 2.3%], p = 0.038) was significantly higher in on-pump CABG group.

CONCLUSIONS

 The OPCAB procedure considerably reduced the occurrence of cardiac death after coronary revascularization. This finding might suggest that the OPCAB procedure should be considered as the first option in patients with higher cardiovascular risk scores. Further research is warranted.

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.

On-pump beating-heart coronary artery bypass grafting in high-risk patients: A systematic review and meta-analysis

BACKGROUND

Operative technique for surgical myocardial revascularization in high-risk patients remains an argument of debate. On-pump coronary artery bypass graft (CABG) with cardioplegic arrest and off-pump CABG have intrinsic limitations. The hybrid approach of on-pump beating-heart CABG (OPBHC) has been proposed over the years with conflicting results. This systematic review and meta-analysis intends to summarize the contemporary literature.

METHODS

A literature search was conducted through major electronic databases. The systematic review provided a total of 279 articles, of those 17 studies were included in the present study.

RESULTS

Compared with on-pump CABG, OPBHC patients showed a preoperative higher risk profile but had reduced early mortality (risk ratio [RR], 0.59, 95% CI, 0.36-0.97) and reduced postoperative stroke (RR, 0.60, 95% CI, 0.39-0.91). Also, interesting trends towards reduced postoperative intra-aortic balloon pump use (RR, 0.56, 95% CI, 0.31-1.01) and myocardial infarction (RR, 0.48, 95% CI, 0.22-1.07) were observed. Baseline characteristics and postoperative complications were similar between OPBHC and off-pump CABG, but limited data are available. The risk of incomplete revascularization in OPBHC is lower than off-pump CABG (RR, 0.53, 95% CI, 0.33-0.87) but higher than conventional on-pump CABG (RR, 1.71, 95% CI, 1.23-2.39).

CONCLUSION

OPBHC is an effective technique to perform surgical revascularization in high-risk patients as preventing haemodynamic deterioration and guaranteeing adequate end-organ perfusion. OPBHC represents an alternative technique to on-pump and off-pump CABG, in those cases in which complications deriving from cardioplegic arrest or manipulation of the heart are more likely. For these reasons, OPBHC might be useful in patients with recent myocardial infarction or with left ventricular dysfunction.

Simultaneous endovascular repair for abdominal aortic aneurysm and coronary artery bypass grafting in an octogenarian: A case report

INTRODUCTION

Coronary artery disease (CAD) is commonly associated with abdominal aortic aneurysms (AAAs) in elderly patients. When severe CAD requiring coronary artery bypass grafting (CABG) is associated with an impending AAA in a high-risk patient, the options for the suitable timing of CABG and AAA repair strategy (one-stage or two-stage) are still being debated.

PRESENTATION OF CASE

An 87-year-old man with non-ST-segment elevation myocardial infarction and a giant abdominal aortic aneurysm was transferred to our centre. Coronary angiography revealed triple-vessel coronary disease, and computed tomography confirmed a giant infrarenal fusiform abdominal aortic aneurysm 9 cm in maximal diameter. We simultaneously performed endovascular aneurysm repair prior to on-pump beating-heart coronary artery bypass grafting. The postoperative course was uneventful, and the patient was discharged on the 15th postoperative day.

CONCLUSION

Combined endovascular aneurysm repair and on-pump beating heart coronary artery bypass grafting in a one-stage operation is a promising strategy to improve therapeutic efficiency in octogenarians. More studies are needed to compare the efficacy and safety of one-stage and two-stage operations to treat concomitant coronary artery disease and aortovascular pathology in the high-risk octogenarian patients.

Intermittent on-pump beating-heart coronary artery bypass grafting-a safer option

Purpose

On-pump beating-heart coronary artery bypass grafting represents a merger of standard on and off-pump techniques and is thought to benefit patients by coupling the dual absence of cardioplegic arrest (conventional coronary surgery), with the hemodynamic instability during manipulation seen in off-pump surgery. However, the clinical benefits are still under discussion. We improvised on the standard on-pump beating-heart surgeries by introducing use of "intermittent" bypass as and when required.

Methods

This study involved 108 patients. "Intermittent" on-pump-beating heart coronary artery bypass grafting was done using suction stabilizer and placing aortic and venous cannula, electively in all patients (group 1) who were supported by pump intermittently (n = 54). Retrospective data of patients who underwent off-pump surgery electively by the same surgeon (group 2, n = 54) was collected.

Results

There was a significant advantage in the number of grafts performed for the lateral surface (circumflex branches) using the new technique compared to conventional technique (68vs22). Similarly, significant advantage was also noted in terms of total number of grafts along with shorter operating times. There were no mortalities in the new group compared to the off-pump group and blood loss was also lesser.

Conclusions

"Intermittent" on-pump coronary revascularization is a technically reliable method of coronary revascularization taking advantage of the off-pump and conventional on-pump techniques while considerably eliminating the disadvantages of both. It has shown its superiority in safety, number of grafts, blood loss, operating time and perioperative course.

On-pump beating heart versus conventional coronary artery bypass grafting: comparative study on early and long-term clinical outcomes

Background

We reviewed our experience with on-pump beating (OPB) heart coronary artery bypass grafting (CABG) to evaluate the impacts of obviating aortic cross-clamping and cardioplegic arrest on clinical outcomes compared with conventional CABG (C-CABG).

Methods

Between 2006 and 2012, elective isolated cardiopulmonary bypass (CPB)-assisted CABG was consecutively performed in 645 patients (mean patient age 63.3±9.1 years, 471 women) with 254 (39.4%) undergoing OPB-CABG and 391 (60.6%) undergoing C-CABG. The early and long-term clinical outcomes were compared between the two groups after adjusting for risk profiles through propensity score (PS) analyses.

Results

The OPB-CABG group presented significant morbidities more frequently than the C-CABG group, including severe chronic kidney disease (CKD) (P=0.026), severe chest pain (P<0.001), and poor left ventricular function (P<0.001). Early mortality occurred in 6 (2.4%) and 2 (0.5%) patients in the OPB- and C-CABG group, respectively (P=0.087). The number of distal anastomosis was comparable between the two groups (3.0±0.9 vs. 3.0±1.0, P=0.816). After PS matching, the incidence of major complications such as stroke (P>0.99) and new-onset dialysis (P=0.109) was comparable. During a median follow-up of 81.0 months (quartiles 1-3, 66.6-95.0 months), 118 patients died and the PS-matched models showed no significant between-group differences in the risk of overall death [hazard ratio (HR), 1.19; 95% confidence interval (CI), 0.72-1.95; P=0.507] and major adverse cardiac events (MACE) (HR, 1.49; 95% CI, 0.67-3.31; P=0.328).

Conclusions

The OPB strategy may be as safe and effective as the conventional strategy during CABG among patients with similar risk profiles. A prospective randomized trial is warranted to better ascertain the beneficial impact of OPB-CABG as both a viable and a durable alternative strategy to C-CABG.

Effect of different surgical type of coronary artery bypass grafting on kidney injury: A propensity score analysis

Acute kidney injury (AKI) after coronary artery bypass grafting (CABG) is associated with a less favorable outcome. Off-pump surgery results in lower kidney dysfunction than conventional on-pump arrest surgery. On-pump arrest surgery results in a lower revascularization rate compared with off-pump surgery. On-pump beating heart (OPBH) CABG combines the advantages of beating heart surgery and cardiopulmonary bypass. This study compared the renal outcomes of 3 cardiac surgical methods. From January 2010 to December 2012, 373 patients who underwent on-pump CABG were enrolled. Propensity analysis was performed to compare the postoperative outcomes of postoperative AKI, renal replacement therapy (RRT), intensive care unit (ICU) stay, mortality, and extubating time. In total, 98 patients received conventional on-pump surgery, 160 received OPBH surgery, and 115 received off-pump surgery. The Society of Thoracic Surgeons scores of these 3 groups were 6.1 ± 13.6, 7.4 ± 13.6, and 5.6 ± 10.9, respectively. Propensity analysis revealed lower AKI incidence in the off-pump group than in the on-pump surgery group. No substantial differences were observed in mortality, RRT, and the ICU stay between the off-pump and OPBH surgery groups. Among the 3 surgical methods, off-pump surgery results in lower AKI incidence. The short-term outcome, including kidney function, of OPBH surgery is similar to that of the off-pump group. Therefore, OPBH surgery is a considerable choice for patients with a high surgical risk.

Lipid emulsion enhances cardiac performance after ischemia-reperfusion in isolated hearts from summer-active arctic ground squirrels

Hibernating mammals, like the arctic ground squirrel (AGS), exhibit robust resistance to myocardial ischemia/reperfusion (IR) injury. Regulated preference for lipid over glucose to fuel metabolism may play an important role. We tested whether providing lipid in an emulsion protects hearts from summer-active AGS better than hearts from Brown Norway (BN) rats against normothermic IR injury. Langendorff-prepared AGS and BN rat hearts were perfused with Krebs solution containing 7.5 mM glucose with or without 1% Intralipid™. After stabilization and cardioplegia, hearts underwent 45-min global ischemia and 60-min reperfusion. Coronary flow, isovolumetric left ventricular pressure, and mitochondrial redox state were measured continuously; infarct size was measured at the end of the experiment. Glucose-only AGS hearts functioned significantly better on reperfusion than BN rat hearts. Intralipid™ administration resulted in additional functional improvement in AGS compared to glucose-only and BN rat hearts. Infarct size was not different among groups. Even under non-hibernating conditions, AGS hearts performed better after IR than the best-protected rat strain. This, however, appears to strongly depend on metabolic fuel: Intralipid™ led to a significant improvement in return of function in AGS, but not in BN rat hearts, suggesting that year-round endogenous mechanisms are involved in myocardial lipid utilization that contributes to improved cardiac performance, independent of the metabolic rate decrease during hibernation. Comparative lipid analysis revealed four candidates as possible cardioprotective lipid groups. The improved function in Intralipid™-perfused AGS hearts also challenges the current paradigm that increased glucose and decreased lipid metabolism are favorable during myocardial IR.