Off-pump coronary artery bypass grafting decreases morbidity and mortality in a selected group of high-risk patients

Effects of different surgical strategies and left ventricular remodelling on the outcomes of coronary artery bypass grafting in heart failure patients with reduced ejection fraction

Background

Ischaemic heart failure with reduced ejection fraction (HFrEF) caused by coronary artery disease accounts for the largest proportion of heart failure cases with the worst prognosis. Coronary artery bypass grafting (CABG) is the most effective treatment for ischaemic HFrEF. On-pump and off-pump are the two surgical methods used for CABG. Whether patients with HFrEF should undergo on- or off-pump CABG is controversial in coronary heart disease surgery. The left ventricular end-systolic volume index (LVSEVI) is the gold standard for evaluating the severity of left ventricular remodelling; however, its effect on the perioperative risk and long-term survival rate of patients with HFrEF undergoing CABG remains unclear.

Methods

This single centre prospective cohort analysis included 118 coronary heart disease patients with symptoms and signs of heart failure and a left ventricular ejection fraction (LVEF) of <40% who were enrolled consecutively from January 2019 to December 2023. Operative mortality, perioperative complications, and long-term survival were compared among patients treated with various LVESVIs and surgical methods. The primary outcomes were cardiac death, myocardial infarction, heart failure, stroke, and revascularization, (percutaneous coronary intervention or redo CABG) with a median follow-up of 38 ± 10 months.

Results

The 30-day postoperative mortality of 118 patients was 6.8%. Patients in the off-pump group had significantly higher perioperative mortality than those in the on-pump group (12.5% vs. 3.8%, p = 0.03). In the off-pump group, a higher proportion of patients required perioperative mechanical assistance, such as intra-aortic artery balloon pump (IABP) or extracorporeal membrane oxygenation (ECMO), compared to those in the on-pump group (IABP: 75% vs. 47.4%, p = 0.004; ECMO: 22.5% vs. 1.3%, p = 0.000). Patients in the off-pump group were more likely to have postoperative atrial fibrillation (AF) (35% vs. 14.1%, p = 0.01). In the on-pump group, the incidence of postoperative AF (25% vs. 6.5%, p = 0.02) and IABP use (62.5% vs. 36.9%, p = 0.03) were significantly higher in patients with more severe left ventricular remodelling than in those with less severe left ventricular remodelling. In the off-pump group, patients with more severe left ventricular remodelling had higher ECMO usage (38.9% vs. 9.1%, p = 0.04), incidence of postoperative AF (61.1% vs. 13.6%, p = 0.02), and perioperative mortality (22.2%). Major adverse cardiac event (MACE)-free survival rate was significantly higher in the on-pump group than in the off-pump group, and there was no significant difference in MACE free survival rates between the two groups of patients with different degrees of left ventricular remodelling.

Conclusion

On-pump bypass is a better surgical procedure for patients with ischaemic HFrEF, especially those with severe left ventricular remodelling. Left ventricular remodelling increases perioperative mortality but has no effect on long-term survival.

Recent Advances in Coronary Artery Bypass Grafting Techniques and Outcomes: A Narrative Review

Coronary artery bypass grafting (CABG) has witnessed remarkable progress in recent years, driven by innovative techniques and refined approaches that have transformed patient outcomes and treatment paradigms. This review article comprehensively explores the latest advances in CABG techniques and their consequential impacts on patient outcomes. The advent of minimally invasive CABG techniques has revolutionized traditional surgical approaches. Robotic-assisted surgery and small thoracotomy methods offer reduced invasiveness, yielding shorter recovery times and improved patient satisfaction. Integrating CABG with percutaneous coronary intervention (PCI), hybrid procedures have emerged as a versatile strategy, providing tailored treatment solutions for complex coronary anatomies. The paradigm shift to off-pump CABG, which preserves the beating heart during surgery, has shown promise in reducing perioperative complications and neurocognitive deficits. Advances in graft selection, particularly the utilization of arterial grafts such as the internal thoracic artery and radial artery, have significantly enhanced graft patency rates and long-term survival. Adjunctive technologies, such as intraoperative imaging and graft flow assessment, have bolstered the precision of CABG procedures. Pharmacological agents have demonstrated their potential to improve graft outcomes. Surgical decision-making is now optimized based on patient characteristics and disease severity owing to the development of patient selection and risk stratification tools. Long-term results have also significantly improved. Patients undergoing CABG have higher survival rates, less angina, and better quality of life. Developing more resilient grafts through tissue engineering, using bioresorbable materials in graft fabrication, and using gene therapy to improve graft patency and overall cardiac recovery are all exciting future research directions. This review's summary of current developments in CABG procedures highlights their profoundly positive effects on patient outcomes. These developments can change the face of cardiovascular care by giving clinicians more tools to treat coronary artery disease (CAD) and enhance patients' quality of life.

On pump coronary artery bypass graft surgery versus off pump coronary artery bypass graft surgery: a review

There are two basic ways of performing coronary artery bypass graft surgery (CABG): on pump CABG and off pump CABG. Off pump CABG is relatively a newer procedure to on-pump CABG and does not require the use of the cardiopulmonary bypass machine. On pump CABG is the more traditional method of performing bypass surgery. However its resultant inflammatory effects cause renal dysfunction, gastrointestinal distress and cardiac abnormalities which have forced the surgeons to look for alternatives to the procedure. An extensive literature search revealed that on pump CABG causes better revascularization as compared to off pump CABG while off pump CABG has a much lower post operative morbidity and mortality especially in high risk patients. We suggest that the technique used should depend on the ease of the surgeon doing the operation as both the methods seem almost equally efficient according to the review.

On-pump vs. off-pump coronary artery bypass surgery at a non-academic community hospital: have biocompatibility improvements eliminated the superiority of off-pump surgery?

OBJECTIVES

Standard coronary artery bypass grafting (CABG) surgery involves cardiopulmonary bypass (CPB) but given concerns over neurological and inflammatory complications related to CPB, many patients receive so-called off-pump procedures (OPCABG). Our objective is to determine if the recent improvements in the biocompatibility of CPB circuitry have improved post-operative outcomes at the community hospital level, particularly in terms of hospital length of stay (LOS), stroke and post-operative infection.

METHODS

We analyzed hospital LOS, incidence of stroke, infection, and mortality along with several clinical variables in 209 patients (38% underwent OPCABG) at a single, non academic community hospital. We constructed a series of forward, stepwise, multiple-variable regression models using mediastinal infection, hospital LOS, and stroke as dependant variables.

RESULTS

OPCABG was associated with a shorter median hospital LOS (3 days vs. 4 days; p=0.0001) and a reduced occurrence of stroke (0% vs. 7.6%; p=0.03). However, mediastinal infections occurred more commonly in OPCABG cases (10% vs. 2.2%; p=0.02). CABG and pre-existing renal disease were predictors of increased hospital LOS (p< 0.0001) whereas CABG was the only factor associated with decreased risk of mediastinal infection (OR=0.21 (0.05-0.80); p=0.02).

CONCLUSIONS

At the community level, OPCABG appears to be superior in terms of LOS and incidence of stroke. Paradoxically, CABG surgery demonstrates a reduced rate of mediastinal infection.

Off-pump coronary artery bypass grafting in a high-risk dextrocardia patient: a case report

We present an interesting but high-risk case of an obese male patient aged 56 years with dextrocardia and a left diaphragmatic hernia. Anterior myocardial infarction was diagnosed in 1994, and the patient later presented with a history of unstable angina. The diagnosis for this chronic smoker was triple-vessel disease, impaired left ventricular function, chronic renal failure, chronic bronchitis, impaired lung function, pulmonary hypertension, hypertension, diabetes, and chronic active gastritis (EuroSCORE of 10). The patient underwent successful off-pump coronary artery bypass grafting with 3 saphenous vein grafts to the left anterior descending, obtuse marginal, and right posterior descending arteries. He was discharged home 8 days later.

Off-pump coronary artery bypass grafting through sternotomy: for whom?

PURPOSE OF REVIEW

Off-pump coronary artery bypass grafting hopes to avoid morbidity associated with cardiopulmonary bypass, improving clinical outcomes. Yet its technical difficulty and unfamiliarity raise concern that adoption of off-pump coronary artery bypass might be associated with poorer outcomes. Both surgeon-specific and patient-related factors are believed to play roles in the success of off-pump coronary artery bypass. This review sought to elucidate these factors.

RECENT FINDINGS

Current prospective data suggest that both techniques have similar rates of mortality but off-pump coronary artery bypass does provide patients with a lower morbidity. Multiple prospective studies suggest a decrease in stroke rates for off-pump coronary artery bypass grafting. There is a consensus that certain patients will have better outcomes if done off-pump. Surgeon experience with the procedure does impact patient outcome.

SUMMARY

Though every patient must be dealt with on an individual basis, it would appear that almost any patient is a candidate for off-pump coronary artery bypass and that, given time and an appropriate desire, most any surgeon can perform the procedure.

Comparison of the effects of on-pump versus off-pump coronary artery bypass surgery on serum prostate-specific antigen levels

AIM

To compare the effects of coronary artery bypass operation with or without extracorporeal circulation on serum total prostate-specific antigen levels.

METHODS

Seventy-six men with a mean age of 57.04+/-9.27 years (range 44-77 years), who underwent coronary artery bypass surgery were enrolled to the study. In 50 patients (Group I), coronary revascularization was performed using extracorporeal circulation, and in 26 patients (Group II) coronary bypass grafting was performed on the beating heart without using extracorporeal circulation. All the patients had serum total prostate-specific antigen levels measured preoperatively and twice postoperatively in the first and fifth postoperative days. Differences in mean total prostate-specific antigen levels between the two groups in the postoperative period were analysed.

RESULTS

The mean preoperative total prostate-specific antigen levels in Group I and Group II were 1.28+/-1.13 ng/mL and 1.11+/-0.93 ng/mL, respectively, and there was no significant difference in the preoperative total prostate-specific antigen values between the two groups (P=0.519). In Group I, postoperative means were 4.96+/-6.29 ng/mL and 5.86+/-9.09 ng/mL in the first and fifth days, respectively (P=0.0001, P=0.0001). Total prostate-specific antigen means in the same postoperative period for Group II were 2.13+/-2.72 ng/mL and 2.00+/-2.20 ng/mL, respectively (P=0.014, P=0.024). The comparison of total postoperative prostate-specific antigen levels between the groups showed significantly higher elevation in Group I (postoperative day 1: P=0.013; day 5: P=0.05).

CONCLUSIONS

Coronary revascularization can cause a statistically significant rise in serum total prostate-specific antigen levels. This rise is more marked in patients undergoing conventional coronary revascularization.

Midterm Results of Off-Pump Coronary Artery Bypass Surgery in 136 Patients: An Angiographic Control Study

BACKGROUND

Off-pump coronary artery bypass surgery may provide an alternative form of surgical revascularization by avoiding the complications of cardiopulmonary bypass (CPB). This study summarizes the midterm results of 136 off-pump bypass surgery patients.

METHODS

Between January 2000 and March 2002, out of 178 surgical myocardial revascularizations, 136 (76.4%) were off-pump bypass surgery. Complete revascularization was done and especially arterial grafts were used. All patients were followed clinically and with treadmill test for 2 years. Average control angiography was performed at the end of 2-year follow-up.

RESULTS

Of all the patients, 56.7% were male and the mean age of the patients was 63.6 +/- 7.4 years. A total of 481 anastomoses were performed-136 (28.27%) to the left anterior descending artery (LAD), 135 (28.07%) to the circumflex coronary artery (Cx) branches, 102 (21.20%) to the right coronary artery (RCA), 108 (22.46%) to the Di. The mean graft number was 3.46. We used 96.6% of patients' left internal mammarian artery (LITA), 29.2% radial artery (RA), 4.4% right internal thoracic artery (RITA), and 100% saphenous vein. There were ischemic changes within 12 patients. All ischemic changes came back to normal within 4 and 18 hours, postoperatively. Mean extubation time was 5.36 +/- 2.23 hours, mean stay in intensive care unit was 17.53 +/- 3.15 hours, mean hospital stay was 5.03 +/- 1.29 days. The LITA patency was 99.25%, RA patency was 97.84%, RITA patency was 100%, and saphenous vein patency was 91.79% with control angiography.

CONCLUSION

Off-pump coronary artery bypass graft (CABG) is efficient procedure with lower index of mortality, morbidity, ICU stay, hospital stay, good wound healing, early socialization, and results in lower costs.

Risk Factors for Myocardial Injury during Off-Pump Coronary Artery Bypass Grafting

BACKGROUND

Although off-pump coronary artery bypass grafting (CABG) is now used worldwide for coronary revascularization, the pre- and intraoperative risk factors for myocardial injury associated with the surgical procedure remain to be elucidated. We performed a multivariate analysis to investigate factors that contribute to myocardial injury during off-pump CABG.

METHODS

The study population consisted of 22 patients who underwent off-pump CABG without apparent intraoperative complications. Blood samples were obtained before surgery and at 3 and 12 hours after the last anastomosis and serum Troponin T (cTnT) levels were measured to assess myocardial injury. Patient characteristics and factors related to preoperative cardiac function and the intraoperative process were analyzed to determine their correlation with serum cTnT levels, and the Spearman's correlation coefficient (r(s)) was computed.

RESULTS

Neither age, preoperative cardiac function, time required for anastomosis, the number of grafts, nor the total amount of bleeding were associated with serum cTnT levels. Serum cTnT at 3 and 12 hours after completed anastomosis correlated with the product of mean systolic blood pressure and mean heart rate (double product) during anastomosis. The r(s) values at 3 and 12 hours were 0.62 (P = .002) and 0.58 (P = .004), respectively. With respect to the serum cTnT level at 12 hours, creatinine clearance (Ccr) had a slight effect on the serum cTnT values.

CONCLUSIONS

High blood pressure and an increased heart rate during anastomosis are unfavorable factors for off-pump CABG. However, strict control of the blood pressure and heart rate makes it possible to subject even patients at high-risk to off-pump CABG from the viewpoints of myocardial injury.

Routine Off-Pump Coronary Artery Bypass: Reasons for On-Pump Conversion

Objective

To assess the feasibility of routine off-pump coronary artery bypass (OPCAB) and investigate risk factors for on-pump conversion.

Methods

Between July 1, 2002, and June 30, 2004, OPCAB was attempted for all patients who required isolated coronary artery bypass in our institution. The perioperative results of patients were prospectively entered into a structured database, and the results were analyzed to identify the risks of requirement for cardiopulmonary bypass.

Results

Off-pump coronary artery bypass was successfully performed in all but 9 patients, giving an OPCAB success rate of 97.3% (329/338). The reason for cardiopulmonary bypass was hemodynamic instability occurring during reoperative surgery in 7, and cardiogenic shock in 2. The OPCAB success rate was significantly higher in primary coronary artery bypass grafting (99.3%, 314/316) than in reoperative coronary artery bypass grafting (68.1%, 15/22; P < 0.0001), and higher in patients without cardiogenic shock (97.9%, 329/336) than in those with cardiogenic shock (0%, 0/2; P < 0.0005). Mean number of distal anastomoses performed under OPCAB was 3.5 ± 1.4. There were 2 hospital deaths (0.6%). During a mean follow-up period of 1.0 ± 0.4 years, 7 patients developed angina, which was treated with catheter intervention; there were no other cardiac events.

Conclusion

Routine OPCAB is feasible with acceptable short-term results. Patients undergoing reoperation or in persistent cardiogenic shock are more likely to require conversion to on-pump coronary artery bypass grafting.

Comparing On-Pump and Off-Pump Coronary Artery Bypass Grafting

One of the most hotly debated and polarizing issues in cardiac surgery has been whether coronary artery bypass grafting (CABG) without the use of cardiopulmonary bypass or cardioplegia (off-pump CABG, or OPCAB) is superior to that performed with the heart-lung machine and the heart’s being chemically arrested (standard CABG). Various clinical trials are reviewed comparing the 2 surgical strategies, including several large retrospective analyses, meta-analyses, and the randomized trials that address different aspects of standard CABG and OPCAB. Although definitive conclusions about the relative merits of standard CABG and OPCAB are difficult to reach from these varied randomized and nonrandomized studies, several generalizations may be possible. Patients may achieve an excellent outcome with either type of procedure, and individuals’ outcomes likely depend more on factors other than whether they underwent standard CABG or OPCAB. Nevertheless, there appear to be trends in most studies. These trends include less blood loss and need for transfusion after OPCAB, less myocardial enzyme release after OPCAB up to 24 hours, less early neurocognitive dysfunction after OPCAB, and less renal insufficiency after OPCAB. Fewer grafts tend to be performed with OPCAB than with standard CABG. Length of hospital stay, mortality rate, and long-term neurological function and cardiac outcome appear to be similar in the 2 groups. To definitively answer the remaining questions of whether either strategy is superior and in which patients, a large-scale prospective randomized trial is required.

Perfusion Flow Assessment of Coronary Shunt during Off-Pump Coronary Artery Bypass Grafting

BACKGROUND

Coronary shunts are widely used to prevent myocardial ischemia during off-pump coronary artery bypass graft (OPCAB) procedures. Although clinical effectiveness has been reported, actual perfusion flow has not been well assessed. The purpose of this study was to evaluate actual shunt flow and its pattern during passive coronary perfusion in clinical OPCAB.

METHODS

In 15 OPCAB cases, the coronary perfusion flow of the external shunt (1.7 or 2.0 mm) during anastomosis and the free flow of the shunt were measured with an in-line electromagnetic or ultrasonic flow probe. The perfused coronary blood vessel was either the left anterior descending coronary artery or the right coronary artery. The inflow vessel of the external shunt was either the femoral artery (FA) or the ascending aorta (AA).

RESULTS

Free flow values of a 1.7-mm FA shunt, 1.7-mm AA shunt, and 2.0-mm FA shunt were 34+/- 7, 39 +/- 3, and 44 +/- 7 mL/min. Perfusion flows were 13 +/- 4, 14 +/- 3, and 22 +/- 4 mL/min, respectively. Perfusion flow was significantly lower than free flow and correlated well with coronary resistance. Although inflow site did not influence net perfusion flow, diastolic/systolic flow fraction ratio was significantly greater when the shunt was perfused from the FA.

CONCLUSIONS

External shunt from FA would provide limited but effective perfusion flow with a physiological pattern, which is passively regulated by coronary resistance.

Evaluation of Myocardial Flow Reserve Using Pharmacological Stress Thallium-201 Single-Photon Emission Computed Tomography: Is There a Difference between Total Arterial Off-Pump Coronary Artery Bypass Grafting and Conventional Coronary Artery Bypass

BACKGROUND

The advantage of total arterial off-pump coronary bypass grafting (OPCAB) over conventional onpump coronary artery bypass grafting with 1 internal thoracic artery and veins (CCAB) in terms of myocardial flow reserve has not been studied. We studied these procedures using thallium- 201 perfusion single-photon emission computed tomography (Tl-201 perfusion SPECT).

METHODS

Between 1997 and 2001, 152 patients were recruited from our database (OPCAB, n = 100; CCAB, n = 52). All patients underwent pharmacological stress Tl-201 perfusion SPECT 3 to 12 months after bypass surgery. Myocardial perfusion was analyzed semiquantitatively with a 5-point scoring system in a 20-segment model (0, normal, to 4, absence of uptake). Summed stress (SSS), rest (SRS), and difference score (SDS) of the entire myocardium as well as average scores (ASS, ARS, ADS) of individual walls (anterior, septal, lateral, and inferior) were compared by Student t test as well as by repeated-measures analysis of variance with Bonferroni correction.

RESULTS

The SSS, SRS, and SDS of OPCAB versus those of CCAB were 6.86 +/- 0.72 versus 7.17 +/- 0.92, 3.95 +/- 0.57 versus 3.75 +/- 0.73, and 2.91 +/- 0.47 versus 3.42 +/- 0.74 (P > .05). However, the lateral wall showed lower scores in OPCAB (ASS, 0.18 versus 0.41, P = .015; ARS, 0.12 versus 0.20, P = .168; ADS, 0.06 versus 0.21, P = .031). The septal wall had higher scores in OPCAB (ASS, 0.33 versus 0.12, P = .003; ARS, 0.18 versus 0.07, P = .037; ADS, 0.14 versus 0.04, P = .030). The anterior and inferior walls were not different between the 2 groups.

CONCLUSIONS

OPCAB led to results similar to those of CCAB. The better results in the lateral wall have been the effect of grafting radial artery rather than vein. The similarity in myocardial reserve in the inferior wall between the 2 groups needs further study. There was no deleterious effect of off-pump as opposed to on-pump CAB.

Why Is Off-Pump Coronary Surgery Uncommon in Canada? Results of a Population-Based Survey of Canadian Heart Surgeons

BACKGROUND

Off-pump coronary artery bypass (OPCAB) is proposed to improve clinical outcomes and decrease resource use. However, off-pump surgery is not widely used in Canada. The purpose of this study was to determine the current use of OPCAB in Canada and determine why surgeons have not adopted this technique.

METHODS AND RESULTS

The study was a population-based survey of all adult Canadian cardiac surgeons in practice >1 year. Eligible division heads and surgeons were contacted by mail. Of 19 806 isolated coronary bypass surgeries performed by respondents in Canada last year, 3164 (16.0%) were performed off-pump. More than 50% of Canadian surgeons performed OPCAB in <5% of coronary cases, and only 17% of surgeons performed OPCAB in >25% of coronary cases. Only 4 responding centers performed OPCAB in >25% of cases. Respondents were divided into those who performed <5% of cases off-pump (nonadopters), 5% to 25% off-pump (intermediate users), or >25% off-pump (enthusiasts). Mean number of distal anastomoses in off-pump cases were 1.7+/-0.6, 1.6+/-0.6, and 3.3+/-0.5 for nonadopters, intermediate users, and enthusiasts, respectively (P=0.001). Eleven percent of nonadopters, 55% of intermediate users, and 81% of enthusiasts believed OPCAB improved clinical outcomes (P<0.0001). Only 23% of all respondents felt OPCAB use would increase in the next 5 years.

CONCLUSIONS

Concerns regarding incomplete revascularization and lack of proven clinical benefit have limited OPCAB to being performed routinely by only a small number of surgeons in Canada.

New surgical therapies for heart failure

A growing number of patients present with heart failure. Some of them may qualify for surgical correction of their cardiac condition. Since heart transplantation will always be available to only a small number of patients, several new surgical techniques have been developed for approval in heart failure patients. Classic interventions such as revascularization, valve repair, or valve replacement have been improved and modified to meet the need of heart failure patients. Several of these techniques are currently under investigation in large clinical trials. These trials will definitely have an impact on the development of surgical treatment of patients with heart failure.