Revascularization of Left Coronary System Using a Skeletonized Left Internal Mammary Artery - Sequential vs. Separate Grafting

Reconstruction Technique Options for Achieving Total Arterial Revascularization and Multiple Arterial Grafting

Ischemic heart disease is the leading cause of morbidity and mortality worldwide and may require coronary revascularization when more severe or symptomatic. Coronary artery bypass grafting (CABG) is the most common cardiac surgical procedure and can be performed with different bypass conduits and anastomotic techniques. Saphenous vein grafts (SVGs) are the most frequently used conduits for CABG, in addition to the left internal thoracic artery. Outcomes with a single internal thoracic artery and SVGs are favorable, and the long-term patency of SVGs may be improved through novel harvesting techniques, preservation methods, and optimal medical therapy. However, increasing evidence points towards the superiority of arterial grafts, especially in the form of multiple arterial grafting (MAG). Nevertheless, the uptake of MAG remains limited and variable, both as a result of technical complexity and a scarcity of conclusive randomized controlled trial evidence. Here, we present an overview of CABG techniques, harvesting methods, and anastomosis types to achieve total arterial revascularization and adopt MAG. We further narratively summarize the available evidence for MAG versus single arterial grafting to date and highlight remaining gaps and questions that require further study to elucidate the role of MAG in CABG.

Angiographic Outcomes for Arterial and Venous Conduits Used in CABG

Coronary artery bypass grafting is the most commonly performed cardiac surgical procedure. Conduit selection is crucial to achieving early optimal outcomes, with graft patency being likely the main driver to long-term survival. We present a review of current evidence on the patency of arterial and venous bypass conduits and of differences in angiographic outcomes.

Is it safe to perform total arterial grafting in elderly patients lacking vein grafts? A single surgeon comparison

OBJECTIVES

The results of coronary artery bypass graft (CABG) surgery with total arterial revascularisation (TA-CABG) in elderly patients, who may have insufficient vein graft material for conventional CABG (CO-CABG), have not been fully established. We therefore sought to compare the short- and long-term outcomes of patients >70 years old undergoing CO-CABG and TA-CABG.

METHODS

We performed a retrospective observational study analyzing all consecutive adult patients aged >70 years undergoing first-time CABG over the 15-year period from 2004 to 2020 under a single surgeon. Primary outcomes of interest were in-hospital mortality, long-term mortality, and re-intervention rate. Secondary outcomes of interest included operative durations and the incidence of peri-operative complications.

RESULTS

There were 46 patients (age 76 ± 3 SD) in the TA-CABG group and 145 patients (age 76 ± 4 SD) in the CO-CABG group. Cardio-pulmonary bypass and cross-clamp durations were comparable between groups (p = .11 and p = .23, respectively). Stroke occurred in 1.0% undergoing CO-CABG compared to 0% in the TA-CABG group (p = .42). Hospital mortality was 3.0% with CO-CABG (EuroSCORE; mean [SD] 6.81 (5.81)) and 2.0% with TA-CABG (EuroSCORE; mean [SD] 6.38 (6.57)) (p = .93). On long-term follow-up, myocardial infarction occurred in 10.0% of CO-CABG patients compared to 4.0% of TA-CABG patients (p = .25). Re-intervention rates were 7% following CO-CABG, and 2% after TA-CABG (p = .23). There was no significant difference in long-term mortality between patients undergoing CO-CABG and TA-CABG (47% vs. 57%, p = .27). Long-term survival was comparable between grafting techniques (p = .27).

CONCLUSIONS

There were no significant differences in major adverse cardiac and cerebrovascular events, re-intervention rate, hospital or long-term mortality between CO-CABG and TA-CABG. TA-CABG represents a safe and feasible alternative to CO-CABG in elderly patients offering good long-term outcomes.

Comparative Analysis Following Implementation of Two Types of Y-Composite Multiarterial Revascularization Strategies at a Single Academic Institution

Background

We compared early outcomes, at a single academic institution, of implementing full coronary revascularization in coronary artery bypass grafting using multiarterial Y‐composite grafts with multiple sequential anastomoses.

Methods and Results

Clinical records of 425 consecutive patients who underwent coronary artery bypass grafting using Y‐grafting with left internal mammary artery and radial artery (Y‐RA group) or right internal mammary artery (Y‐RIMA group) from 2015 to 2019, were reviewed. These were compared with the institutional experience of isolated coronary artery bypass grafting cases (in situ on pump/off pump) for the same period of time. When comparing the 4 groups, the Y‐RIMA/RA groups revealed a higher number of distal anastomosis than the in situ on‐ or off‐pump groups. When the number of distal arterial anastomosis was analyzed, there was a superiority of using the Y‐configuration compared with the in situ approach. Moreover, there were no significant differences among groups for mortality and/or major adverse cardiac and cerebrovascular events in hospital or at 30‐day follow‐up. A subanalysis comparing the Y‐RIMA group with the Y‐RA group showed that complementary grafts to the Y‐construct were required to accomplish full revascularization more frequently in the Y‐RIMA group. Full‐arterial revascularization was achieved in 92.2% of the Y‐RA group and 72.0% of the Y‐RIMA group (P<0.001). In 82.8% of the Y‐RA group and 30.8% of the Y‐RIMA group, revascularization was completed as an anaortic procedure (P<0.001).

Conclusions

The 2 types of arterial Y‐composite grafting were able to be introduced in the routine practice of our institution showing comparable results to the established institutional practice. This procedure allowed for more arterial distal anastomosis to be performed safely without compromising outcomes.

The patency of graft and anastomoses in sequential and individual coronary artery bypass grafting: A meta-analysis

Objective:

To compare the patency of graft and anastomoses in sequential and individual coronary artery bypass grafting (CABG).

Methods:

Our study used the Cochrane Library database, Excerpta Medica database, Web of Science, and PubMed. Studies comparing the outcomes of graft or anastomosis patency were assessed independently by two reviewers to identify the literature of satisfaction. We used Review Manager and STATA software for statistical analysis.

Results:

Fifteen cohort studies were analyzed, including 10681 patients, 12957 grafts, and 4341 anastomoses, under sequential and individual CABG. Compared with the sequential group, the individual one is statistically significant in the graft patency [risk ratio (RR)=1.07, 95% confidence interval (CI ) 1.01–1.13; p=0.02] and anastomosis patency (RR=1.06, 95% CI 1.01–1.12; p=0.005).

Conclusion:

Our study suggested that the patency of the individual group, in terms of graft and anastomosis patency, is better than that of the sequential one.

Patients over 70 years of age with moderate ischemic mitral regurgitation undergoing surgical revascularization plus mitral valve repair: insights from a single-center study of propensity-matched data

Background

Elderly patients, compared with the young, have a higher burden of surgical risk factors with reduced functional capacity and increased comorbidities conditions, and may have worse clinical outcomes. So far, few reports have focused on clinical outcomes of patients over 70 years of age with moderate chronic ischemic mitral regurgitation (IMR) undergoing mitral valve repair at the time of coronary artery bypass grafting (CABG). This single-center study of propensity-matched data attempts to answer a question: compared with patients with age of 70 or less, whether patients over 70 years of age with moderate IMR undergoing CABG plus mitral valve repair receive poor outcomes.

Methods

All eligible patients were included in this study and were entered into either an elderly group (n=142) or a control group (n=182) according to patients' age. In-hospital outcomes (consisting of surgical mortality and major postoperative morbidity) and midterm clinical outcomes (including all-cause mortality and recurrent mitral regurgitation) were compared after propensity score matching (1:1).

Results

Using propensity-score matching, 103 pairs of patients were successfully established in a 1:1 ratio. No significant differences between the two matched groups were found with regard to surgical mortality (5.8% vs. 3.9%, P=0.754) and major postoperative morbidity. A total of 184 patients (91 in the elderly group and 93 in the control group) received regular follow-up visit with the median duration of 38 months [interquartile range (IQR), 27-56 months]. There were not any significant differences between the two matched groups regarding overall survival and recurrent IMR-free survival (stratified log-rank P=0.185 and stratified log-rank P=0.453, respectively). The elderly group as compared to the control group did not affect midterm mortality via cox proportional hazard regression (propensity score adjusted hazard ratio, 1.143; 95% confidence interval, 0.761-1.943; P=0.285).

Conclusions

Patients over 70 years of age with moderate chronic IMR undergoing combined CABG and mitral valve repair may receive favorable in-hospital and midterm clinical outcomes.

Elderly Patients with Moderate Chronic Ischemic Mitral Regurgitation: Coronary Artery Bypass Grafting Alone or Concomitant Mitral Annuloplasty?

Background

An increasing number of elderly patients with ischemic mitral regurgitation (IMR) are referred for coronary artery bypass grafting (CABG). However, data about the management of elderly patients with moderate IMR are scanty. This study evaluates the impacts of two surgical approaches (CABG alone or concomitant mitral annuloplasty (MAP)) on in-hospital and midterm outcomes, to attempt to determine an appropriate treatment option for elderly patients with moderate chronic IMR.

Methods

All eligible patients over 65 years of age were included and were entered into either a MAP group (patients undergoing CABG plus MAP, n = 96) or a CABG group (patients receiving CABG alone, n = 104). Baseline and surgical characteristics were analyzed, and in-hospital and midterm outcomes between groups were compared after propensity score-matching (1 : 1).

Results

Using propensity score-matching, 82 pairs of patients were successfully established in a 1 : 1 ratio. No significant differences between the two matched groups were found regarding surgical mortality (4.9% vs. 1.2%, p=0.173) and major postoperative morbidity. 150 patients (76 in the MAP group and 74 in the CABG group) received regular follow-up visit with the median duration of 37 months. Compared with the CABG group, the MAP group received a similar overall survival but a better recurrent MR-free survival (stratified log-rank p, 0.492 and < 0.001, respectively). Using Cox regression, the MAP group as compared with the CABG group did not affect midterm survival probability (propensity score-adjusted hazard ratio, 0.854; 95% confidence interval, 0.571–2.729, p=0.630). Additionally, patients in the MAP group had a significantly lower ratio of NYHA class III-IV at the latest follow-up by comparison with patients in the CABG group (19.7% vs. 35.5%, p=0.033).

Conclusion

Compared with CABG alone, concomitant mitral annuloplasty is associated with improved midterm outcomes (including reduced IMR recurrence and improved cardiac functional class) but shares similar surgical mortality and major postoperative morbidity and may be a promising treatment option for elderly patients with moderate chronic IMR.

Surgical treatment of symptomatic left anterior descending myocardial bridges: myotomy vs. bypass surgery

PURPOSE

To compare the effects of myotomy and bypass surgery for treating myocardial bridges (MBs) over the left anterior descending artery (LAD) in a single-center observation study.

METHODS

Fifty-four eligible patients (34 males, median age of 60 years old) with symptomatic LAD-MBs who underwent myotomy (31 patients) or bypass surgery (23 patients) were included in this study. The primary endpoints were the occurrence of major adverse cardiac events (MACEs) and angiographic demonstration of adverse angiographic results.

RESULTS

No surgical death was observed. During a median follow-up of 26 months, 11 patients developed MACEs (7.4% for myotomy vs. 40.9% for bypass surgery, p = 0.007). Surgical strategy (bypass surgery vs. myotomy) was an independent risk factor for MACEs (odds ratio = 3.681, 95% confidence interval 1.814-8.685, p = 0.011). Myotomy compared with bypass surgery had a significantly lower incidence of adverse angiographic results (3.7% of residual compression vs. 40.9% of LIMA graft failure, p = 0.003). Among ten patients suffering from LAD-MBs with concomitant proximal coronary stenosis who underwent bypass surgery, only one reported transient recurrent exertional chest pain, and all LIMA grafts were patent.

CONCLUSIONS

Myotomy of symptomatic LAD-MBs may be associated with encouraging midterm results. Bypass surgery may be recommended for treating symptomatic LAD-MBs with concomitant proximal coronary stenosis.

Long-Term Patency Rate of Radial Artery Conduits in Chinese Patients Undergoing Off-Pump Coronary Artery Bypass Grafting

Consensus has yet to emerge among experts as to whether the radial artery (RA) conduit was superior to the saphenous vein (SV) graft for coronary artery bypass grafting (CABG) in terms of long-term patency. This study aimed to evaluate long-term patency of the RA conduit compared to the SV conduit for off-pump CABG, and to screen the independent predictors of long-term RA graft failure.Patients < 80 years of age with graftable triple-vessel disease undergoing non-emergent, primary, isolated off-pump CABG, using both the RA and the SV conduits, were reviewed. Graft patency, all-cause mortality and repeat revascularization were followed-up. The independent predictors of long-term RA graft failure were identified.A total of 296 out of 320 eligible patients (42 females, 61.3 ± 9.9 years old) received follow-up with an observed period of 93.4 ± 16.5 months. All-cause mortality was 14.5%, and repeat revascularization was conducted on 6 RA grafts and 9 SV grafts. Superior patency of the RA grafts compared to the SV grafts was observed (84.4% versus 78.5%, P = 0.035). Independent predictors of long-term RA graft failure included proximal stenosis of target right coronaries < 90% (OR = 2.35, 95%CI 1.41-5.82) and diabetes mellitus (OR = 1.66, 95%CI 1.17-4.26).The RA graft had a superior long-term patency than the SV graft. Long-term patency of the RA graft may be poor in diabetics or in the case of proximal stenosis of target right coronary <90%. (Trial registration: ChiCTR-OCH-1200212).

Patency of Individual and Sequential Coronary Artery Bypass in Patients with Ischemic Heart Disease: A Meta-analysis

Objective

To evaluate the patency of individual and sequential coronary artery bypass in patients with ischemic heart disease.

Methods

We searched PubMed, Cochrane Library, Excerpta Medica Database, and ClinicalTrials.gov databases for controlled trials. Endpoints included graft patency, anastomosis patency, occluded rates in left anterior descending (LAD) system and right coronary artery (RCA) system, in-hospital mortality, and follow-up mortality. Pooled risk ratios (RRs) and standardized mean difference (SMD) were used to assess the relative data.

Results

Nine cohorts, including 7100 patients and 1440 grafts under individual or sequential coronary artery bypass. There were no significant differences between individual and sequential coronary artery bypass in the graft patency (RR=0.96; 95% CI=0.91-1.02; P=0.16; I²=87%), anastomosis patency (RR=0.95; 95% CI=0.91-1.00; P=0.05; I²=70%), occluded rate in LAD system (RR=1.03; 95% CI=0.92-1.16; P=0.58; I²=37%), occluded rate in RCA system (RR=1.36; 95% CI=0.72-2.57; P=0.35; I²=95%), in-hospital mortality (RR=1.57; 95% CI=0.92-2.69; P=0.10; I²=0%), and follow-up mortality (RR=0.96; 95% CI=0.36-2.53; P=0.93; I²=0%).

Conclusion

No significant differences on clinical data were observed regarding anastomosis patency, occluded rate in LAD system, occluded rate in RCA system, in-hospital mortality, and follow-up mortality, indicating that the patency of individual and the patency of sequential coronary artery bypass are similar to each other.

Impacts of incomplete revascularization following off-pump coronary artery bypass grafting on clinical outcomes of patients with triple-vessel lesions: insights from a single-center study of propensity-matched data

Background

Although complete revascularization (CR) has been a goal of surgical revascularization, comorbidities and anatomical variables often conspire against a successful surgical CR. Currently, incomplete revascularization (IR) has been also considered as an acceptable strategy of surgical revascularization in some categories of patients. In the past decade, off-pump coronary artery bypass grafting (CABG) became one of the mainstream procedures of CABG due to its low incidence of perioperative complications. However, the magnitude of the impacts of off-pump IR on clinical outcomes of patients with triple-vessel disease remained unclear.

Methods

Eligible patients who received isolated off-pump CABG with left internal mammary artery (LIMA) grafting to the left anterior descending coronary artery (LAD) in our institute from January 2011 to December 2013 were entered into an IR group or a CR group. The incidence of off-pump IR was investigated. In-hospital and follow-up outcomes were also evaluated by adjusting baseline characteristics using propensity score matching (1:1).

Results

A total of 1,349 patients (268 in the IR group and 1,081 in the CR group) were analyzed. The off-pump IR rate was 19.9%. Using matching propensity scores, 234 pairs were successfully established in a 1:1 manner. The two matched groups had similar surgical mortality and major postoperative morbidity. Multivariate Cox regression analysis showed that IR was not an independent predictor of cardiac death at follow-up (HR =1.215; 95% CI, 0.883-2.164; P=0.371). The two matched groups received a similar cumulative survival freedom from repeat revascularization in Kaplan-Meier curves (χ²=2.120, log-rank P=0.145).

Conclusions

CR can be achieved in the majority of off-pump CABG cases. Compared with off-pump CR, off-pump IR with the LIMA grafting to the LAD was associated with acceptable clinical outcomes.

Off-pump onlay-patch grafting using the left internal mammary artery for a diffusely diseased left anterior descending artery: in-hospital and mid-term outcomes

BACKGROUND

The aims of this study were to evaluate the in-hospital and mid-term outcomes of the off-pump onlay-patch grafting procedure using the left internal mammary artery (LIMA) for a diffusely diseased left anterior descending artery (LAD) and to identify the risk factors for postoperative LIMA graft failure in a single-center retrospective study.

PATIENTS AND METHODS

A total of 63 patients (52 males, 65.7±9.0 years) undergoing LAD arteriotomy with or without concomitant endarterectomy, followed by reconstruction using LIMA onlay-patch at the time of off-pump coronary artery bypass grafting at our institute from January 2014 to December 2016 were reviewed. The operative mortality, major postoperative morbidity, follow-up all-cause mortality, major adverse cardiac events at follow-up, and postoperative LIMA graft patency were analyzed. The risk factors for postoperative LIMA graft failure on the basis of baseline and surgical characteristics were identified by multivariable logistic regression analysis.

RESULTS

Eighteen (28.6%) patients underwent concomitant open LAD endarterectomy. The operative mortality rate was 1.6%. Major postoperative morbidity included perioperative myocardial infarction (3.2%), low cardiac output (1.6%), and reoperation for bleeding (1.6%). During the follow-up period of 24.2±9.5 months, all-cause mortality was 1.7% and the incidence of major adverse cardiac events was 6.8%. No repeat revascularization was recorded. In total, 88.1% of LIMA grafts showed FitzGibbon grade A patency determined by noninvasive coronary computed tomography angiography during follow-up. In addition, concomitant LAD endarterectomy and intraoperative LIMA graft flow were found to be independent risk factors for mid-term LIMA graft failure by multivariable logistic regression analysis (odds ratio=2.681, 95% confidence interval: 1.314-9.856, P=0.007 and odds ratio=0.932, 95% confidence interval: 0.791-0.976, P=0.021, respectively).

CONCLUSION

Revascularization of a diffusely diseased LAD using the off-pump LIMA onlay-patch technique results in encouraging clinical outcomes with favorable angiographic results. Concomitant LAD endarterectomy and intraoperative LIMA graft flow are associated with the risk of postoperative LIMA graft failure.

Bilateral internal thoracic artery grafting: in situ or composite?

Bilateral internal thoracic artery (BITA) grafting is considered a superior choice for coronary artery bypass grafting (CABG). While the 10-year outcomes of BITA grafting from the recent Arterial Revascularization Trial (ART) are still pending, numerous observational studies have demonstrated the advantages of BITA grafting. These include better long-term graft patency and freedom from arteriosclerosis, in addition to higher survival rate compared to CABG using only the left internal thoracic artery (ITA). The different BITA configurations are in situ and composite-the choice of optimal grafting configuration is challenging. Patient factors such as coronary anatomy, presence of a diseased ascending aorta and the potential need for a future redo sternotomy will influence the choice of the grafting strategy. In situ BITA grafting is associated with excellent clinical outcomes and has been extensively described in the literature. However, uncertainties remain regarding the ideal in situ configuration and design. Composite BITA grafting is the other option that maximizes right ITA (RITA) utilization. In this configuration, the RITA is able to reach the distal circumflex and right coronary artery branches. This approach decreases the need for a third graft conduit.

Sequential Saphenous Vein Coronary Bypass Grafting

The enormous majority of previous reports focused on evaluating the safety and efficacy of sequential saphenous vein (SV) coronary bypass grafting; however, no reports to date have revealed concern regarding the impacts of the number of distal anastomoses of sequential SV grafting on graft patency after coronary artery bypass grafting (CABG). This single-center retrospective study aimed to evaluate the impacts of three versus two distal anastomoses per single SV conduit on SV graft patency after off-pump CABG, and to determine the independent risk factors for sequential SV graft failure.From January 2011 to December 2014, 1320 eligible patients were assigned to either a triple group (three distal anastomoses of sequential SV grafting, n = 758) or a double group (two distal anastomoses of sequential SV grafting, n = 562). The primary endpoint was over a 2-year follow-up SV graft failure after off-pump CABG.The triple and double group received a similar total patency rate of sequential SV conduits (86.5% versus 87.1%, P = 0.757). The number of distal anastomoses of sequential SV grafting (three versus two) was not a predictive factor for the follow-up graft failure of sequential SV conduits (HR = 0.91, 95% CI: 0.66-2.29, P = 0.137). Moreover, the two groups received a similar follow-up survival freedom from repeat revascularization (χ² = 1.881, log-rank P = 0.170).Three versus two distal anastomoses per single SV conduit received a similar SV graft patency. The number of distal anastomoses of sequential SV grafting was not an independent risk factor for graft failure.