Long-term outcomes of patients with diabetes receiving bilateral internal thoracic artery grafts

Multiarterial vs Single-Arterial Coronary Surgery: 10-Year Follow-up of 1 Million Patients

BACKGROUND

Although many options exist for multivessel coronary revascularization, controversy persists over whether multiarterial grafting (MAG) confers a survival advantage over single-arterial grafting (SAG) with saphenous vein in coronary artery bypass grafting (CABG). This study sought to compare longitudinal survival between patients undergoing MAG and those undergoing SAG.

METHODS

All patients undergoing isolated CABG with ≥2 bypass grafts in The Society of Thoracic Surgeons Adult Cardiac Surgery Database (2008-2019) were linked to the National Death Index. Risk adjustment was performed using inverse probability weighting and multivariable modeling. The primary end point was longitudinal survival. Subpopulation analyses were performed and volume thresholds were analyzed to determine optimal benefit.

RESULTS

A total of 1,021,632 patients underwent isolated CABG at 1108 programs (100,419 MAG [9.83%]; 920,943 SAG [90.17%]). Median follow-up was 5.30 years (range, 0-12 years). After risk adjustment, all characteristics were well balanced. At 10 years, MAG was associated with improved unadjusted (hazard ratio, 0.59; 95% CI 0.58-0.61) and adjusted (hazard ratio, 0.86; 95% CI, 0.85-0.88) 10-year survival. Center volume of ≥10 MAG cases/year was associated with benefit. MAG was associated with an overall survival advantage over SAG in all subgroups, including stable coronary disease, acute coronary syndrome, and acute infarction. Survival was equivalent to that with SAG for patients age ≥80 years and those with severe heart failure, renal failure, peripheral vascular disease, or obesity. Only patients with a body mass index ≥40 kg/m2 had superior survival with SAG.

CONCLUSIONS

Multiarterial CABG is associated with superior long-term survival and should be the surgical multivessel revascularization strategy of choice for patients with a body mass index of less than 40 kg/m2.

Effect of bilateral internal thoracic artery harvesting on deep sternal wound infection in diabetic patients: Review of literature

Instead of its documented superiority of patency and long-term outcomes, the bilateral internal thoracic artery grafts are underused in the general population, and its use is controversial and debatable in diabetic patients due to long surgery duration, post-surgical bleeding, and sternal wound complications such as sternal wound infection, mediastinitis, and sternal wound dehiscence. This review article is particularly focused on deep sternal wound infection (DSWI) of bilateral internal thoracic artery (BITA) grafts in diabetic patients with comparison to single internal thoracic artery (SITA) graft.

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Bilateral internal thoracic artery grafting is superior to single internal thoracic artery grafting in terms of outcomes.

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Bilateral internal thoracic artery grafting is underused, especially in diabetic patients.

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The risk of DSWI in skeletonized BITA grafting in diabetic patients is almost similar to SITA grafting.

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Skeletonized BITA grafting should be encouraged in selected diabetic patients.

The risk of mediastinitis and deep sternal wound infections with single and bilateral, pedicled and skeletonized internal thoracic arteries

Bilateral internal thoracic artery (BITA) grafting may prolong survival in coronary artery bypass graft (CABG) patients, but its use has been curtailed due to concerns of deep sternal wound infections (DSWI) resulting in mediastinitis. This article examines the association of single internal thoracic artery (SITA) and BITA grafting and the role of harvesting techniques with the development of DSWI in CABG patients. The development of DSWI following BITA grafting is multifactorial and is independent of the harvesting technique.

Saphenous graft atherosclerosis as assessed by optical coherence tomography data for stenotic and non-stenotic lesions from the OCTOPUS registry

Introduction

Coronary artery bypass grafting (CABG), although widely used for a long time in diffuse coronary artery disease (CAD), has serious limitations associated with graft aging and its degeneration.

Aim

The relationship between saphenous vein graft (SVG) plaque morphology assessed by optical coherence tomography (OCT) and clinical findings has not been elucidated yet.

Material and methods

We compared the morphology of SVG in stenotic vs. non-stenotic lesions using OCT imaging in 29 patients hospitalized in our center within the OCTOPUS registry.

Results

Stenotic lesions were characterized by higher incidence of thin-cap fibroatheroma (TCFA) (33% vs. 0%, p = 0.0048), thrombus (28% vs. 0%, p = 0.0008), lipid-rich plaque (LRP) (75% vs. 35%, p = 0.0013) and plaque within the SVG valve (19% vs. 0%, p = 0.0114) as compared to non-stenotic lesions. Patients with intimal tearing or rupture (ITR) were older (75.8% vs. 68.9 years, p = 0.047) and had lower left ventricular ejection fraction (LVEF) (32.0% vs. 49.7%, p = 0.001) and glomerular filtration rate (GFR) (36.0 vs. 73.6 ml/min/1.73 m², p = 0.010). Patients with calcified lesions vs. those without had lower high-density lipoprotein (HDL) cholesterol (33.2 vs. 44.1 mg/dl, p = 0.018), similarly to those with ruptured plaque vs. those without (28.3 vs. 41.7 mg/dl, p = 0.047).

Conclusions

Presence of ITR was associated with advanced age, decreased LVEF and renal insufficiency. Decreased concentration of HDL was associated with higher occurrence of calcified and ruptured plaque.

Bilateral internal thoracic arteries: what is the State of the ART?

PURPOSE OF REVIEW

To provide a broad overview of the current state of knowledge of coronary artery bypass grafting with bilateral internal thoracic artery (BITA).

RECENT FINDINGS

There exists a large body of literature from mostly observational studies supporting the use of BITA in patients undergoing coronary artery bypass grafting but selection bias is a major issue with nonrandomized data. The precise method of BITA use does not appear to impact graft patency nor clinical outcomes - in other words, BITA in any configuration appears to be protective. The major downside is the increased risk of sternal complications, which can be mitigated with sternal-sparring adjuncts. The 5-year interim results of the landmark Arterial Revascularization Trial comparing BITA versus single internal thoracic artery did not show a clinical benefit for BITA but the end-of-trial results are pending. Despite wide guideline support for BITA use, uptake in the surgical community remains low and this is likely because of technical and institutional barriers.

SUMMARY

The published literature thus far supports surgical revascularization with BITA and we eagerly await the 10-year Arterial Revascularization Trial results. The general consensus is that a greater proportion of surgical revascularization should be performed using BITA.

Scoring system to guide decision making for the use of bilateral internal mammary arteries: The BIMA score

OBJECTIVE

Currently, surgeons are unable to estimate whether the survival benefit from bilateral internal mammary artery (BIMA) grafting outweighs the increased deep sternal infection (DSWI) risk in the individual cases. As a consequence BIMA grafting is still largely underutilized. We aimed to develop and validate a scoring system to predict the individual risk for DSWI and 10 year survival probability to guide surgeons in decision making process for the use of BIMA over single internal mammary artery (SIMA).

METHODS

Fast backward elimination on predictors was performed using Lawless and Singhal method. BIMA score was reported as a partial nomogram that can be used to manually obtain predicted individual risk of DSWI and 10 year survival probability from the regression models. Bootstrapping validation of the regression models was performed.

RESULTS

The study population consisted of 5234 patients of which a total of 960 (18%) received BIMA and the remaining 4274 (82%) underwent conventional strategy using SIMA. A total of 119 patients experienced DSWI (2.3%). A total of 489 deaths were recorded after a median follow-up time of 5.68 years (interquartile range 2.7-8.8, range 0-12.1). BIMA grafting was found to have effect on both risk of DSWI and 10 year survival probability and was included into partial nomograms. Bootstrapping validation confirmed a good discriminative power of the models.

CONCLUSION

The BIMA score provides an impartial assessment of the decision making process for clinicians to establish the optimum revascularization strategy for individual patients.

Liberal bilateral internal thoracic artery use in people with diabetes neutralizes the negative impact of insulin-requiring status

AIMS

Bilateral internal thoracic artery (BITA) grafts are underused in insulin-dependent diabetic patients because of increased risk of postoperative complications. The impact of the insulin-requiring status on outcomes after routine BITA grafting was investigated in this retrospective study.

METHODS

Skeletonized BITA grafts were used in 3228 (71.6%) of 4508 consecutive patients having multivessel coronary disease who underwent isolated coronary bypass surgery at the authors' institution from January 1999 to August 2015. Among these BITA patients, diabetes mellitus and the insulin-requiring status were present in 972 (30.1%) and 237 (7.3%) cases, respectively. After the one-to-one propensity score-matching, 215 pairs of insulin-dependent/noninsulin-dependent people with diabetes were compared as the postoperative outcomes. The operative risk was calculated for each patient according to the logistic European System for Cardiac Operative Risk Evaluation (logistic EuroSCORE).

RESULTS

As expected, insulin-dependent people with diabetes had higher risk profiles than noninsulin-dependent people with diabetes (median logistic EuroSCORE, 4.1 vs. 3.5%, P = 0.086). However, there were no differences in in-hospital mortality both in unmatched and propensity score-matched series (2.5 vs. 2%, P = 0.65 and 2.8 vs. 1.9%, P = 0.52, respectively). In propensity score-matched pairs, only prolonged invasive ventilation (P = 0.0039) and deep sternal wound infection (P = 0.071) were more frequent in insulin-dependent people with diabetes. No differences were found as the late outcomes.

CONCLUSION

In diabetic patients, the insulin-requiring status is by itself a risk factor neither for in-hospital death nor for poor late outcomes after routine BITA grafting. Only the risk of prolonged invasive ventilation and deep sternal wound infection are increased early after surgery.

Can the onset of heart failure be delayed by treating diabetic cardiomyopathy?

The pathophysiology of diabetic cardiomyopathy (DC) is not fully understood. This frequently undiagnosed complication of chronic hyperglycemia leads to heart failure (HF). However, it is suggested that an appropriate metabolic control of diabetes at an early stage of this deleterious disease, is able to inhibit the development and progression of DC to HF. Recently, it has been postulated that myocardial ischaemia plays an important role in the development of this pathology. Results of the antianginal pharmacological treatment and revascularization are unsatisfactory and reveal a gap in our knowledge and current approaches to treating DC. Most recent studies emphasize the ischaemic component of DC as a key target for therapeutic strategies, which could change its unfavorable history. More stress is put on an early diagnosis of coronary artery disease (CAD), promoting prompt revascularization. Choosing the accurate time of surgical revascularization, with the inclusion of the metabolic background, can ensure complete revascularization with better prognosis. This review will focus on the complexity of DC and summarize contemporary knowledge of treatment strategies for patients with diabetes and CAD.

Prospective validation of a predictive scoring system for deep sternal wound infection after routine bilateral internal thoracic artery grafting

OBJECTIVES

The Gatti score is a weighted scoring system based on risk factors for deep sternal wound infection (DSWI) that has been specifically created to predict DSWI risk after routine bilateral internal thoracic artery (BITA) grafting. It has not undergone an external validation. The aim of the present study was to perform this validation.

METHODS

BITA grafts were used as skeletonized conduits in 304 (90.7%) of 335 consecutive patients with multivessel coronary artery disease who underwent isolated coronary bypass surgery at the authors' institution between January 2014 and July 2015. Baseline characteristics, operative data and immediate outcomes of every patient were prospectively collected in a computerized data registry. A score was assigned to each patient preoperatively. The goodness-of-fit and the discrimination power of both models, preoperative and combined, of the Gatti score were assessed with the Hosmer-Lemeshow test and the calculation of the area under the receiver-operating characteristic curve, respectively.

RESULTS

Eighteen (5.9%) patients suffered from DSWI. Major differences were found between the original series whence the Gatti score has been derived and the present prospective series. The Gatti score goodness-of-fit was satisfactory for both the preoperative (P = 0.61) and the combined model (P = 0.81). The area under the receiver-operating characteristic curve was 0.82 (95% confidence interval: 0.72-0.91) for the preoperative model and 0.8 (95% confidence interval: 0.71-0.9) for the combined model.

CONCLUSIONS

On the basis of the results of the present prospective study, the Gatti score has proved to be effective in predicting DSWI following BITA grafting despite some differences between the original and the present series of patients. More studies have to be performed in order to strengthen the evidence of this first external validation.

The Impact of Diabetes on Early Outcomes after Routine Bilateral Internal Thoracic Artery Grafting

BACKGROUND

Increased risk of postoperative complications limits use of bilateral internal thoracic artery (BITA) grafting in diabetic patients. The authors' experience in routine BITA grafting was reviewed to investigate the impact of diabetes on early outcomes.

METHODS

Among the 4508 consecutive patients with multivessel coronary artery disease who underwent isolated coronary bypass surgery from January 1999 throughout August 2015, skeletonised BITA grafts were used in 3228 (71.6%) patients, 972 diabetic and 2256 non-diabetic. After one-to-one propensity score (PS)-matched analysis, 819 pairs of diabetic/non-diabetic patients were compared for postoperative outcomes. The operative risk was calculated for each patient according to the European System for Cardiac Operative Risk Evaluation II (EuroSCORE II).

RESULTS

Although diabetic had higher risk profiles than non-diabetic patients both in unmatched (EuroSCORE II: 5.3±7.3% vs. 3±4.2%, p<0.0001) and PS-matched series (EuroSCORE II: 5.1±7.1% vs. 3.6±4.3%, p<0.0001), there were no differences in hospital mortality (2.2% vs. 1.8%, p=0.52 and 2.1% vs. 2.3%, p=0.74, respectively). In PS-matched pairs, the use of adrenergic agonists (p=0.03), postoperative bleeding (p=0.0055) and deep incisional sternal wound infection (p=0.0018) were more frequent in diabetic patients who had a mean of longer hospital stays (p=0.023).

CONCLUSIONS

Bilateral internal thoracic artery grafting may be routinely performed even in diabetic patients despite higher risk profiles. Increased postoperative complications prolong hospital stay but do not impact on early mortality.

The Society of Thoracic Surgeons Clinical Practice Guidelines on Arterial Conduits for Coronary Artery Bypass Grafting

Internal thoracic arteries (ITAs) should be used to bypass the left anterior descending (LAD) artery when bypass of the LAD is indicated (class of recommendation [COR] I, level of evidence [LOE] B). As an adjunct to left internal thoracic artery (LITA), a second arterial graft (right ITA or radial artery [RA]) should be considered in appropriate patients (COR IIa, LOE B). Use of bilateral ITAs (BITAs) should be considered in patients who do not have an excessive risk of sternal complications (COR IIa, LOE B). To reduce the risk of sternal infection with BITA, skeletonized grafts should be considered (COR IIa, LOE B), smoking cessation is recommended (COR I, LOE C), glycemic control should be considered (COR IIa, LOE B), and enhanced sternal stabilization may be considered (COR IIb, LOE C). As an adjunct to LITA to LAD (or in patients with inadequate LITA grafts), use of a RA graft is reasonable when grafting coronary targets with severe stenoses (COR IIa, LOE: B). When RA grafts are used, it is reasonable to use pharmacologic agents to reduce acute intraoperative and perioperative spasm (COR IIa, LOE C). The right gastroepiploic artery may be considered in patients with poor conduit options or as an adjunct to more complete arterial revascularization (COR IIb, LOE B). Use of arterial grafts (specific targets, number, and type) should be a part of the discussion of the heart team in determining the optimal approach for each patient (COR I, LOE C).

Pure Bilateral Internal Thoracic Artery Grafting in Diabetic Patients With Triple-Vessel Disease

BACKGROUND

Despite the documented superior long-term patency of bilateral internal thoracic artery (BITA) grafting, use of BITAs remains low, especially in diabetic patients. We analyzed the results of pure BITA grafting to determine whether the potential survival advantage outweighs the risk of wound infection in diabetic patients.

METHODS

We performed a retrospective analysis of 791 consecutive patients (389 diabetic, 402 nondiabetic) with triple-vessel disease who underwent off-pump coronary artery bypass using only skeletonized BITAs from 2001 to 2010. We used propensity score matching to match 315 nondiabetic patients with diabetic patients.

RESULTS

The groups did not differ significantly regarding 10-year survival (diabetic, 84.2% ± 4.5%; nondiabetic, 80.8% ± 4.7%; p = 0.828) or freedom from major adverse cardiovascular events (diabetic, 73.5% ± 5.2%; nondiabetic, 71.8% ± 5.3%; p = 0.431). Diabetes was not predictive of deep sternal infection (odds ratio, 1.11; 95% confidence interval, 0.23 to 5.31; p = 0.895). Results of stratified competing risks regression analysis showed that the risk of target vessel revascularization in diabetic patients was similar to that of nondiabetic patients (subdistribution hazard ratio, 0.67; 95% confidence interval, 0.16 to 2.80; p = 0.585).

CONCLUSIONS

Off-pump coronary artery bypass grafting using pure BITAs produced excellent clinical outcomes in both diabetic and nondiabetic patients. This strategy did not increase the incidence of deep sternal infection in diabetic patients. We recommend BITA grafting, which has proven long-term patency, as a strategy of choice in diabetic patients.

Off-pump Bilateral Internal Thoracic Artery Grafting

BACKGROUND

The long-term benefit of bilateral internal thoracic grafts (BITA) is well established. BITA grafting is often avoided in diabetic, female, obese, elderly and other high-risk patients because of concerns for deep sternal wound infection. The objective of this study is to analyse early results of our BITA grafting and to establish the safety of BITA use in all patients.

METHODS

All cases of isolated consecutive unselected CABG were included in this retrospective study. BITA were used in-situ - one was used to graft left anterior descending artery and the other was used as inflow for a composite graft with radial artery. Dual inflow using in situ BITA grafting allows easy bailout by using an additional vein graft.

RESULTS

BITA was used in 574 patients out of 602 (95.35%). Incidence of early death was 1.33% (8/602), stroke 0.5% (3/602), reoperation for bleeding 0.17% (1/602). Deep sternal wound infection was not seen in any patient but nine patients (1.5%) had superficial wound infection which healed with dressing.

CONCLUSION

We have used BITA in 95% of our unselected, consecutive off-pump CABG patients without any major wound complications. Our limited experience has shown off-pump CABG using BITA grafting can be safely adopted routinely with excellent early result.

Surgical revascularization techniques that minimize surgical risk and maximize late survival after coronary artery bypass grafting in patients with diabetes mellitus

OBJECTIVE

To identify surgical revascularization techniques that minimize surgical risk and maximize late survival in patients with diabetes undergoing coronary artery bypass grafting (CABG).

METHODS

From January 1972 to January 2011, 11,922 patients with diabetes underwent primary isolated CABG. The revascularization techniques investigated included bilateral internal thoracic artery (BITA) grafting (n=938; 7.9%) versus single ITA (SITA) grafting, off-pump (n=602; 5.0%) versus on-pump CABG, and incomplete (n=2109; 18%) versus complete revascularization. The median follow-up was 7.8 years and total follow-up, 104,516 patient-years. Multivariable analyses were performed to assess the effects of surgical techniques on hospital outcomes and long-term mortality.

RESULTS

After adjusting for patient characteristics, BITA versus SITA grafting was associated with a 21% lower late mortality (68% confidence limits, 16%-26%). However, BITA grafting was also associated with more deep sternal wound infections (DSWIs), but the considerable mortality from DSWI minimally affected overall survival because of its rare occurrence. The risk factors for DSWI were female sex (80% increased risk), higher body mass index (7% increased risk per kg/m2), medically treated diabetes (73% increased risk), previous myocardial infarction (58% increased risk), and peripheral arterial disease (73% increased risk). Off-pump and on-pump CABG had similar results. Complete versus incomplete revascularization had similar hospital outcomes; however, complete revascularization was associated with 10% lower late mortality (68% confidence limits, 7.0%-13%).

CONCLUSIONS

BITA grafting with complete revascularization maximizes long-term survival and is recommended for patients with diabetes undergoing CABG. BITA grafting should be used in all patients with diabetes whose risk of DSWI is low. It might be best avoided in obese diabetic women with diffuse atherosclerotic burden-those at greatest risk of developing these infections.

Conduits for coronary bypass: strategies

Strategic planning is integral to any operation but complexity varies immensely and therefore the effort necessary to create the optimal plan. The previous three reports have discussed individual conduits and herein is an attempt to present approaches to common situations which the author favors. Although much has been learned over 45 years about use and subsequent behavior of venous and arterial grafts we continue to learn and, as a result, evolve new strategies or modify those now popular. Thus the reader must recognize that in spite of trying to be balanced and inclusive all surgeons have personal opinions and also prejudices which influence the approach taken and which may not be the optimal one for others or for the patient.