Incomplete Revascularization After Coronary Artery Bypass Graft Operations Is Independently Associated With Worse Long-Term Survival

Hybrid coronary revascularization: position paper of the European Society of Cardiology Working Group on Cardiovascular Surgery and European Association of Percutaneous Cardiovascular Interventions

Myocardial revascularization in coronary artery disease via percutaneous coronary intervention or coronary artery bypass graft (CABG) surgery effectively relieves symptoms, significantly improves prognosis and quality of life when combined with guideline-directed medical therapy. Hybrid coronary revascularization is a promising alternative to percutaneous coronary intervention or CABG in selected patients and is defined as a planned and/or intended combination of consecutive CABG surgery using at least 1 internal mammary artery to the left anterior descending (LAD), and catheter-based coronary intervention to the non-LAD vessels for the treatment of multivessel disease. The main indications for hybrid coronary revascularization are (i) to achieve complete revascularization in patients who cannot undergo conventional CABG, (ii) to treat patients with acute coronary syndromes and multivessel disease with a non-LAD vessel as the culprit lesion that needs revascularization and (iii) in highly select patients with multivessel disease with complex LAD lesions and simple percutaneous coronary intervention targets for all other vessels. Hybrid coronary revascularization patients receive a left internal mammary artery graft to the LAD artery through a minimal incision along with percutaneous coronary intervention to the remaining diseased coronary vessels using latest generation drug-eluting stents. A collaborative environment with a dedicated heart team is the optimal platform to perform such interventions, which aim to improve the quality and outcome of myocardial revascularization. This position paper analyses the rationale of hybrid coronary revascularization and the currently available evidence on the various techniques and delves into the sequence of the interventions and pharmacological management during and after the procedure.

Impact of complete revascularization in coronary artery bypass grafting for ischemic cardiomyopathy

Objective

In patients with ischemic cardiomyopathy, coronary artery bypass grafting ensures better survival than medical therapy. However, the long-term clinical impact of complete revascularization remains unclear. This observational study aimed to evaluate the effects of complete revascularization on long-term survival and left ventricular functional recovery in patients with ischemic cardiomyopathy undergoing coronary artery bypass grafting.

Methods

We retrospectively reviewed outcomes of 498 patients with ischemic cardiomyopathy who underwent complete (n = 386) or incomplete (n = 112) myocardial revascularization between 1993 and 2015. The baseline characteristics were adjusted using inverse probability of treatment weighting to reduce the impact of treatment bias and potential confounding. The mean follow-up duration was 77.2 ± 42.8 months in survivors.

Results

The overall 5-year survival rate (complete revascularization, 72.5% vs incomplete revascularization, 57.9%, P = .03) and freedom from all-cause death and/or readmission due to heart failure (54.5% vs 40.1%, P = .007) were significantly greater in patients with complete revascularization than those with incomplete revascularization. After adjustments using inverse probability of treatment weighting, the complete revascularization group demonstrated a lower risk of all-cause death (hazard ratio, 0.61; 95% confidence interval, 0.43-0.86; P = .005) and composite adverse events (hazard ratio, 0.59; 95% confidence interval, 0.44-0.79; P < .001) and a greater improvement in the left ventricular ejection fraction 1-year postoperatively (absolute change: 11.0 ± 11.9% vs 8.3 ± 11.4%, interaction effect P = .05) than the incomplete revascularization group.

Conclusions

In patients with ischemic cardiomyopathy undergoing coronary artery bypass grafting, complete revascularization was associated with better long-term outcomes and greater left ventricular functional recovery and should be encouraged whenever possible.

Clinical Insights to Complete and Incomplete Surgical Revascularization in Atrial Fibrillation and Multivessel Coronary Disease

Objectives

Although endorsed by international guidelines, complete revascularization (CR) with Coronary Artery Bypass Grafting (CABG) remains underused. In higher-risk patients such as those with pre-operative atrial fibrillation (AF), the effects of CR are not well studied.

Methods

We analyzed patients' data from the HEIST (HEart surgery In AF and Supraventricular Tachycardia) registry. Between 2012 and 2020 we identified 4770 patients with pre-operative AF and multivessel coronary artery disease who underwent isolated CABG. We divided the cohort according to the completeness of the revascularization and used propensity score matching (PSM) to minimize differences between baseline characteristics. The primary endpoint was all-cause mortality.

Results

Median follow-up was 4.7 years [interquartile range (IQR) 2.3-6.9]. PSM resulted in 1,009 pairs of complete and incomplete revascularization. Number of distal anastomoses varied, accounting for 3.0 + -0.6 vs. 1.7 + -0.6, respectively. Although early (< 24 h) and 30-day post-operative mortalities were not statistically different between non-CR and CR patients [Odds Ratio (OR) and 95% Confidence Intervals (CIs): 1.34 (0.46-3.86); P = 0.593, Hazard Ratio (HR) and 95% CIs: 0.88 (0.59-1.32); P = 0.542, respectively] the long term mortality was nearly 20% lower in the CR cohort [HR (95% CIs) 0.83 (0.71-0.96); P = 0.011]. This benefit was sustained throughout subgroup analyses, yet most accentuated in low-risk patients (younger i.e., < 70 year old, with a EuroSCORE II < 2%, non-diabetic) and when off-pump CABG was performed.

Conclusion

Complete revascularization in patients with pre-operative AF is safe and associated with improved survival. Particular survival benefit with CR was observed in low-risk patients undergoing off-pump CABG.

What does complete revascularization mean in 2021? - Definitions, implications, and biases

PURPOSE OF REVIEW

Coronary revascularization is known to be an excellent treatment for coronary artery disease. However, whether incomplete myocardial revascularization compromises long-term outcomes, as compared to complete revascularization (CR), remains contentious. Herein, we review the concept of and evidence on CR/incomplete revascularization (ICR) and discuss future perspectives.

RECENT FINDINGS

When possible, achieving CR in coronary artery bypass grafting is desirable; nonetheless, ICR is also a reasonable option to balance the therapeutic benefits against the risks.

SUMMARY

Although angiography-based assessment currently remains the standard of care, fractional flow reserve guidance may reduce the number of lesions requiring revascularization, which may be helpful for an appropriate surgical revascularization strategy. In particular, utilizing this approach may refine hybrid revascularization procedures, especially among high-risk patients.

Rate of Incomplete Revascularization Following Coronary Artery Bypass Grafting at a Single Institution Between 2007 and 2017

Incomplete revascularization following coronary artery bypass grafting (CABG) is associated with increased repeat revascularization, myocardial infarction and death. Whether the rate of incomplete revascularization is increasing over time has not been previously described. All patients with multivessel coronary artery disease who underwent isolated and elective CABG at our Institution in 2007 (n = 291) were compared to patients who underwent CABG in 2017 (n = 290). A Revascularization Index Score was created to compare rates of incomplete revascularization between the 2 years based on the coronary anatomy and degree of stenosis. Comparison of the 2 years disclose that the rate of incomplete revascularization increased from 17.9% in 2007 to 28.3% in 2017 (p = 0.003) and was accompanied by a decline in the Revascularization Index Score from 0.73 to 0.67 (p = 0.005). Left ventricular function improved in both groups following CABG. Two-year cardiovascular mortality was significantly higher in the 2017 cohort compared to the 2007 cohort. These differences may be attributable to patient factors including more severe coronary artery disease associated with older age, greater incidence of smoking and previous percutaneous coronary intervention. In conclusion, the rate of incomplete revascularization following CABG significantly increased in 2017 compared to 2007 and was associated with higher cardiovascular mortality.

Incomplete revascularization: what the surgeon needs to know

For many years, the concept of "complete revascularization" (CR) was considered an absolute truth in coronary surgery with improved long-term survival and a lower rate of reintervention. This was derived from early publications which showed a survival benefit for patients undergoing coronary artery bypass grafting (CABG) who received CR. Many advances in the field of coronary revascularization have been made in the years that passed since those publications, including more frequent use of percutaneous coronary intervention (PCI) in patients with multivessel disease (MVD). This has led some to question the importance of CR and raise the option of "reasonable incomplete revascularization" (IR) for selected patients. The definition of CR is variable in the literature with the two most common definitions being an anatomical (revascularization of all coronary segments with stenosis and larger than a predefined size) and a functional definition (where revascularization is considered complete if all ischemic and viable territories are reperfused). No randomized control trials have been conducted to compare complete versus IR, and a significant proportion of data is based on post hoc analysis of data from randomized control trials and registries. Multiple studies have proven that CR is achieved more frequently with CABG then with PCI. A review of the available data from the past three to four decades shows a trend toward improved results with CR, regardless of the reperfusion strategy chosen. This should impact the heart team discussion when choosing a revascularization strategy and impact the surgical decision making while preforming CABG. IR can be part of a hybrid revascularization strategy or be reserved for rare cases where the cost of achieving CR much outweighs the benefit.

Dual inflow, total-arterial, anaortic, off-pump coronary artery bypass grafting: how to do it

Coronary surgery performed on an arrested heart, using one internal mammary artery and a saphenous vein carries two main potential drawbacks: the known failure rate of vein grafts and the relatively high rate of neurologic injury. To address these concerns, we describe a technique that achieves complete revascularization without manipulating the ascending aorta (anaortic, off-pump) and utilizing total arterial grafts. All patients undergo thorough preoperative investigation, including bilateral carotid, vertebral and subclavian artery Duplex ultrasounds. A pulmonary artery catheter, transoesophageal echocardiography, and point-of-care coagulation testing are used in each case. The left and right internal mammary arteries and non-dominant radial artery are harvested using a fully skeletonised technique. Wide bilateral extrapleural retrothymic tunnels are developed and the pericardium is opened widely to facilitate cardiac positioning. A tandem graft is constructed with the right internal mammary artery (RIMA) in situ and radial artery using an end-to-end anastomosis. This graft is brought into the pericardium and through the transverse sinus in order to graft the lateral and inferior walls with multiple sequential distal anastomoses. The left internal mammary artery (LIMA) in situ is used to graft the anterior wall. Four main cardiac positions (high and low lateral walls, inferior and anterior walls) are obtained using a combination of off-pump stabilizer positioning, alternate tension on pericardial 'heart-strings', table tilting and folded wet sponges. All distal anastomoses are performed using silastic intracoronary shunts and an off-pump myocardial stabilizer. All grafts are checked using transit-flow time measurements. Milrinone is continued overnight and dual antiplatelet therapy is continued for 3 months postoperatively.