Off-pump minimally invasive coronary artery bypass grafting in patients with left ventricular dysfunction: the lampang experience

Introduction

The minimally invasive cardiac surgery off-pump coronary artery bypass (MICSOPCAB) is technically difficult; therefore, previous studies have indicated that MICSOPCAB should be contraindicated in patients with impaired left ventricular (LV) function. In this study, we investigated the feasibility of MICSOPCAB in patients with impaired LV function.

Methods

The 226 patients underwent MICSOPCAB between August 2017 and September 2022. Our study defined impaired LV function as ejection fraction (EF) in echocardiography 40% or less. The patients were divided into Low EF group (n = 39) and Normal EF group (n = 187).

Results

The Low EF group was in a more critical preoperative condition than Normal EF group (41.0% in the Low EF group vs. 14.4% in the Normal EF group; p < 0.001). For preoperative transthoracic echocardiography, LV end-diastolic diameter (5.5 ± 0.9 cm in the Low EF group vs. 5.0 ± 0.8 cm in the Normal EF group; p < 0.001) and LV end-systolic diameter (4.4 ± 1.0 cm in the Low EF group vs. 3.4 ± 1.0 cm in the Normal EF group; p < 0.001) were significantly larger in the Low EF group. No differences were found in the operative time (180 [160-240] min in the Low EF group vs. 205 [165-253] min in the Normal EF group; p = 0.231) and the median number of distal anastomoses (2 [1-2] in the Low EF group vs. 2 [1-3] in the Normal EF group; p = 0.073). Intensive care unit stay was longer in the Low EF group than in the Normal EF group (2 [1-2] in the Low EF group vs. 1 [1-2] in the Normal EF group; p = 0.010). Perioperative transfusion was more common in the Low EF group than in the Normal EF group (69.7% vs. 49.2%; p = 0.023). There were no differences in major complications, hospital stay, and 30-day mortality. The Kaplan-Meier curve showed no significant difference in postoperative major adverse cardiac or cerebrovascular events rates between the two groups (p = 0.185).

Conclusion

In this study, MICSOPCAB can be performed in patients with low EF having short- and mid-term outcomes similar to patients with normal EF. Therefore, low EF should not be contraindicated in MICSOPCAB.

The Significance of Systemic Immune-Inflammatory Index for Mortality Prediction in Diabetic Patients Treated with Off-Pump Coronary Artery Bypass Surgery

Diabetes mellitus (DM) represents a complex carbohydrate metabolism disorder characterized by inflammatory over-reactivity. The study aimed to investigate the potential influence of postoperative inflammatory activation on mortality risk after off-pump coronary artery bypass grafting in diabetic patients. There were 510 patients treated with off-pump coronary artery bypass grafting due to stable complex coronary artery disease, including 175 patients with type-2 DM (T2DM.) The mean follow-up time was 3.7 +/− 1.5 years with a 9% all-cause mortality rate in the diabetic group. In multivariable analysis, preoperative comorbidities (stroke, peripheral artery disease, postoperative systemic inflammatory index >952, and postoperative left ventricle ejection fraction (LVEF) < 45%) were revealed as prognostic factors. The receiver operator characteristics curve analysis for postoperative calculations of systemic immune-inflammatory index (SII) appeared significant (AUC = 0.698, p = 0.008), yielding sensitivity of 68.75% and specificity of 71.07%. Systemic immune-inflammatory index (SII) can be regarded as a predictive marker for long-term prognosis in diabetic patients after off-pump coronary artery bypass grafting. The role of perioperative inflammatory activation may play a crucial role in mortality prediction.

Gender differences in coronary artery diameters and survival results after off-pump coronary artery bypass (OPCAB) procedures

Background

Cardiovascular disease is still the leading cause of death among men and women. The gender related survival differences following off-pump surgery was the subject of the study with relation to coronary arteries diameters according to sizes of intraluminal shunts applied during surgery.

Methods

We retrospectively collected data of 2,772 patients who were referred for surgical revascularization in our department between 2010 and 2018 with mean follow up period of 76 months. Patients underwent coronary artery bypass grafting with off-pump technique (OPCAB) with intraluminal shunts application during each anastomosis.

Results

The multivariate Cox’s proportional hazards model revealed male sex as significant all-cause mortality risk factor [hazard ratio (HR) =4.62; 95% confidence interval (CI): (3.12–6.83)]. The survival proportion was significantly lower in male than female (73% vs. 94%; P<0.0001) within 130 months of follow up despite favorable results of coronary artery diameters. Mean ± standard deviation (SD) diameters of coronary arteries measured by shunts applied during off-pump revascularization were 1.81±0.28 vs. 1.7±0.26 mm (P<0.0001) for left anterior descending artery (LAD) anastomosis, 1.78±0.27 vs. 1.71±0.29 mm (P<0.0001) for circumflex artery (Cx) anastomosis and 1.77±0.28 vs. 1.72±0.31 mm (P>0.05) for right coronary artery (RCA) anastomosis in men and women subgroups, respectively.

Conclusions

Female sex is associated with better overall late survival following surgical revascularization despite smaller diameters of coronary arteries in direct measurement with the use of intraluminal shunt application.

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

Coronary artery bypass grafting remains the standard treatment for patients with extensive coronary artery disease. Coronary surgery without use of cardiopulmonary bypass avoids the deleterious systemic inflammatory effects of the extracorporeal circuit. However there is an ongoing debate surrounding the clinical outcomes after on-pump versus off-pump coronary artery bypass (ONCAB versus OPCAB) surgery. The current review is based on evidence from randomized controlled trials (RCTs) and meta-analyses of randomized studies. It focuses on operative mortality, mid- and long-term survival, graft patency, completeness of revascularisation, neurologic and neurophysiologic outcomes, perioperative complications and outcomes in the high risk groups. Early and late survival rates for both OPCAB and ONCAB grafting are similar. Some studies suggest early poorer vein graft patency with off-pump when compared with on-pump, comparable midterm arterial conduit patency with no difference in long term venous and arterial graft patency. A recent, pooled analysis of randomised trials shows a reduction in stroke rates with use off-pump techniques. Furthermore, OPCAB grafting seems to reduce postoperative renal dysfunction, bleeding, transfusion requirement and respiratory complications while perioperative myocardial infarction rates are similar to ONCAB grafting. The high risk patient groups seem to benefit from off-pump coronary surgery.

Lung cancer resection with concurrent off-pump coronary artery bypasses: safety and efficiency

BACKGROUND

To assess the safety and efficacy of combined surgery for patients with concurrent lung cancer and severe coronary heart disease (CHD).

METHODS

Between 2003 and 2014, 34 patients with stage I or II lung cancer and simultaneous severe CHD underwent combined off-pump coronary artery bypass (OPCAB) grafting and lung resection. Surgically, myocardial revascularization was performed first and followed by lobectomies through the same or a second incision. Video-assisted thoracoscopes were used in some cases. Five patients also received chemotherapy before or after combined surgery in an effort to improve the long-term survival.

RESULTS

All patients survived the operation and no new myocardial infarctions (MIs) occurred in the perioperative period. The most frequent complications were cardiac arrhythmias (5 cases), atelectasis (4 cases), and pulmonary infections (2 cases). All patients were followed up for 5-60 months. Within this period, 6 patients (17.6%) died due to cancer recurrence. The 3- and 5-year survivals were 75% and 67% for these lung cancer patients, respectively.

CONCLUSIONS

Combined OPCAB and pulmonary resection for early stage lung cancer patients with concurrent severe CHD is a relatively safe and effective treatment with satisfactory long-term survival rates, especially for those patients with three-vessel disease who are not usually candidates for percutaneous coronary intervention (PCI) before open surgery.

Impact of different dosage of protamine on heparin reversal during off-pump coronary artery bypass: a clinical study

INTRODUCTION

Currently, a dose of protamine equal to 1 mg for each 100 units of heparin given is used to reverse the residual heparin activity following off-pump coronary artery bypass. We hypothesized that a 1:1 ratio (ratio of protamine to heparin) could be higher than necessary inducing post-operative disturbance of hemostasis.

METHODS

Between January and March 2014 in 9 patients undergoing off-pump coronary artery bypass, we evaluated the effect of a dose of protamine equal to 1 mg per 100 units of heparin (Total Calculated Dose) on hemostasis as evaluated by means of thromboelastomery. Two data analyses were performed: the first after the administration of 2/3 of the Total Calculated Dose of protamine and the second after the administration of the Total Calculated Dose of protamine.

RESULTS

We found that the administration of 2/3 of Total Calculated Dose of protamine was always able to reverse the anticoagulant effect of heparin and that a significant clotting time elongation was induced by the infusion of the second part of the Total Calculated Dose of protamine. No modification in clot firmness was observed.

CONCLUSIONS

The present study seems to suggest that the commonly applied ratio equal to 1:1 (ratio of protamine to heparin) could be higher than needed with potential and hazardous impacts on the efficacy of the coagulation system.

Clopidogrel improves aspirin response after off-pump coronary artery bypass surgery

We sought to assess the incidence of aspirin resistance after off-pump coronary artery bypass (OPCAB) surgery, and investigate whether clopidogrel can improve aspirin response and be safely applied early after OPCAB surgery. Sixty patients who underwent standard OPCAB surgery were randomized into two groups. One group (30 patients) received mono-antiplatelet treatment (MAPT) with aspirin 100 mg daily and the other group received dual antiplatelet treatment (DAPT) with aspirin 100 mg daily plus clopidogrel 75 mg daily. Platelet aggregations in response to arachidonic acid (PL_AA) and adenosine diphosphate (ADP) (PL_ADP) were measured preoperatively and on days 1 to 6, 8 and 10 after the antiplatelet agents were administered. A PL_AA level above 20% was defined as aspirin resistance. Postoperative bleeding and other perioperative variables were also recorded. There were no significant differences between the two groups in baseline characteristics, average number of distal anastomosis, operation time, postoperative bleeding, ventilation time and postoperative hospital stay. However, the incidence of aspirin resistance was significantly lower in the DAPT group than that in the MAPT group on the first and second day after antiplatelet agents were given (62.1% vs. 32.1%, 34.5% vs. 10.7%, respectively, both P < 0.05). There was no significant difference in postoperative complication between the two groups. DAPT with aspirin and clopidogrel can be safely applied to OPCAB patients early after the procedure. Moreover, clopidogrel reduces the incidence of OPCAB-related aspirin resistance.

Off-pump coronary artery bypass grafting using skeletonized in situ arterial grafts

Skeletonization is an advanced technique of graft harvesting for coronary artery bypass grafting (CABG), and while it requires meticulous attention, it has many advantages. For example, skeletonization of internal thoracic artery (ITA) can minimize sternal ischemia and lower the risk of mediastinitis, and is longer and larger than pedicled ITA. In this article we describe the surgical techniques demonstrated in our video, which details our techniques of skeletonization of arterial grafts and off-pump coronary artery bypass (OPCAB) exclusively using these in situ grafts. Our method of right gastroepiploic artery (GEA) skeletonization has only three technical steps. The first step is to pass thin vessel loops under the GEA. The second step is to unroof the tissue surrounding the GEA. The last step is to seal and sever all the branches. Skeletonization of the GEA not only prevents vasospasm but also leads to GEA dilatation, and facilitates inspection and makes sequential anastomosis easier. Bilateral use of the skeletonized ITA and use of the skeletonized GEA can cover most coronary artery target sites without any manipulation of the ascending aorta. In our consecutive series of over 1,000 patients, the stroke rate was 0.5%. Our method helps to make the technique simple and secure in this technically demanding operation, and we believe that OPCAB with these grafts provides the best possible coronary revascularization.