Internal Thoracic Artery Bypass Grafts Research Articles

Bilateral versus single internal thoracic coronary artery bypass grafting: the ART RCT

Background There is debate whether the use of more arterial grafts during coronary artery bypass graft surgery provides advantages to the standard operation using the left internal thoracic artery plus vein grafts. We review data from the Arterial Revascularisation Trial to determine whether there is support for the multiple arterial graft hypothesis. Methods Patients undergoing coronary artery bypass graft for clinical reasons and who provided written informed consent were randomised to standard coronary artery bypass graft using the single internal thoracic artery or use of bilateral internal thoracic arteries. Additional vein grafts could be used. The primary outcome was all-cause mortality at 10 years and exploratory analyses were carried out to test the multiple arterial graft hypothesis. Results A total of 3102 patients were enrolled (1548 bilateral internal thoracic artery and 1554 single internal thoracic artery). Follow-up to 10 years for vital status was 98% complete. In the bilateral group, 14% of patients received a single internal thoracic artery only and use of radial artery grafts occurred in about 20% of patients in both groups. Aspirin was used in 81% of the patients, beta-blockers in 74%, statins in 90% and angiotensin-converting enzyme inhibitors or angiotensin receptor blockers in 73%. At 10 years, death rates were 20.3% and 21.2% in the bilateral internal thoracic artery and single internal thoracic artery groups, respectively (hazard ratio 0.96, 95% confidence intervals 0.82 to 1.12; p = 0.62) and composite of all-cause mortality, myocardial infarction or stroke 24.9% and 27.3%, respectively (hazard ratio 0.90, 95% confidence interval 0.79 to 1.03; p = 0.12). Exploratory analyses using the ‘as-treated’ approach indicate that outcomes were better in patients who received multiple arterial grafts (adding the right internal thoracic and/or radial arteries) compared with a single arterial graft. This effect appeared to be greater in patients with diabetes and those aged 70 years or less. Use of total arterial grafting without vein grafts may provide the best outcomes. Limitations The elevated cross-over rate between bilateral internal thoracic artery and single internal thoracic artery and the non-randomised use of radial artery grafts may have contributed to a loss of power to detect a difference in mortality between the two groups. Moreover, secondary analyses are prone to bias as they compare non-randomised groups. Conclusions The Arterial Revascularisation Trial is one of the largest long-term studies in cardiac surgery. The primary analysis did not show a mortality benefit for bilateral internal thoracic artery at 10 years, perhaps due to high crossover rates in the bilateral internal thoracic artery group and concomitant use of the radial artery. Secondary analyses suggest a mortality benefit for patients receiving multiple arterial grafts compared with single arterial graft with possible greater effects in patients with diabetes and separately in patients aged 70 years or above. The trial will follow patients to 15 years and the continuing Randomized Comparison of the Clinical Outcome of Single versus Multiple Arterial Grafts trial will further test the multiple arterial graft hypothesis. Trial registration This trial is registered as ISRCTN46552265. Funding This project was funded by the British Heart Foundation, the UK. Medical Research Council and the National Institute for Health and Care Research (NIHR) Efficacy and Mechanism Evaluation programme and will be published in full in Efficacy and Mechanism Evaluation; Vol. 10, No. 7. See the NIHR Journals Library website for further project information.

Left internal thoracic artery bypass graft.

A 77-year-old man presented with chest discomfort on exertion for several weeks. Thirty-one years prior, he had performed on-pump coronary artery bypass grafting (CABG) using the pedicled left internal thoracic artery (LITA) to left anterior descending artery (LAD) and saphenous vein grafts (SVGs). The SVGs to the left circumflex artery had already occluded and to the right coronary artery (RCA) had previously required percutaneous coronary intervention (PCI). Although an electrocardiogram showed no remarkable change and echocardiography showed findings of known old posterior myocardial infarction, single-photon emission computed tomography demonstrated new inferior myocardial ischemia. Coronary angiography showed occlusion of all native coronary artery and severe stenosis of the residual SVG to RCA. On the other hand, the 31-year-old LITA graft revealed excellent patency (Panel and Supplementary material online, Video). Since the 1980s, the LITA for LAD grafting has been a cornerstone of CABG surgery.1 The European Society of Cardiology guideline recommends grafting with internal thoracic artery to the LAD as Class I.2 Furthermore, LITA graft had better patency than SVG for 20 years post-operatively.3 This case showed the over 30 years patency of LITA graft, although the use of a pump or the harvesting method might affect patency. This case indicated that it is precisely in patients less than 50 years of age scheduled for CABG that LITA to the LAD should be utilized.

Coronary artery bypass in infants with left main coronary artery atresia using an internal thoracic artery bypass graft

Coronary artery bypass in infants with left main coronary artery atresia using an internal thoracic artery bypass graft

Bilateral internal thoracic artery coronary bypass grafting

The OBJECTIVEof the study was to assess the immediate results of the use of two internal thoracic arteries during coronary bypass surgery.MATERIAL AND METHODS. 200 patients with coronary artery disease underwent coronary artery bypass grafting in Samara cardiology dispensary from 2016 to 2018. Patients were divided into 2 groups. Group 1 (100 people) used both internal thoracic arteries (ITA) and the radial artery as conduits; group 2 (100 people) used the left ITA and the great saphenous vein as conduits. The duration of the operation, complications in the early postoperative period, and hospital mortality were evaluated.RESULTS. Groups (1 – 73 % of men, average age (59±12) years, average number of conduits – (3.1±0.4), 2 – 62 % of men, average age (67±7) years, average number of conduits – (3.3±0.6)) were significantly different only in age. The average duration of the operation in the group 1 was (174±25) min, in 2 – (165±18) min (p<0.05). Hospital mortality in the group 1 – 0 %, in 2 – 1 % (p>0.05). The number of complications in the early postoperative period did not have a statistically significant difference between the groups.CONCLUSION. Bilateral internal thoracic arteries coronary artery bypass grafting in CHD patients did not lead to a significant increase in the duration of the operation, an increase in mortality and infectious complications from the sternum, compared with single internal thoracic arteries grafting.

Bilateral internal thoracic artery versus radial artery multi-arterial bypass grafting: a report from the STS database†.

Multi-arterial bypass grafting with bilateral internal thoracic (BITA-MABG) or radial (RA-MABG) arteries improves long-term survival, but its increased complexity raises perioperative safety concerns. We compared perioperative outcomes of RA-MABG and BITA-MABG using the Society of Thoracic Surgeons Adult Cardiac Surgery Database (STS-ACSD). We analysed the 2004-2015 BITA-MABG and RA-MABG experience in STS-ACSD. Primary end points were operative mortality (OM) and deep sternal wound infections (DSWI). Risk-adjusted odds ratios [AOR (95% confidence interval)] were derived via multivariable logistic regression. Sensitivity analyses were done in patient sub-cohorts and based on institutional BITA-utilization rates (<5%, 5-10%, 10-20%, 20-40% and >40%). Eighty-five thousand nine hundred five RA-MABG (82.5% men; 61 years) and 61336 BITA-MABG (85.1% men; 59 years) patients were analysed; 41.6% of BITA-MABG and 27.3% of RA-MABG cases came from institutions with low MABG utilization rates (<10%). Unadjusted OM was equivalent for both techniques (BITA-MABG versus RA-MABG: 1.3% vs 1.2%, P = 0.79), while DSWI was lower for RA-MABG (1.0% vs 0.6%, P < 0.001). RA-MABG was associated with lower adjusted OM [AOR = 0.80 (0.69-0.96)] and DSWI [AOR = 0.39 (0.32-0.46)]. Sensitivity analyses confirmed robustness of these findings. Equivalent outcomes were observed at high BITA-use institutions where BITA cases comprised >20% of all cases for OM and ≥40% for DSWI. This analysis of the STS-ACSD showed that RA-MABG is a generally safer form of multi-arterial coronary artery bypass grafting surgery. However, this advantage is mitigated at institutions with substantial BITA experience.

Aortic valve replacement via a right parasternal approach in a patient with a history of coronary artery bypass surgery and pericardiectomy: a case report

BackgroundThe number of patients who require aortic valve replacement after coronary artery bypass grafting continues to increase. Re-operative cardiovascular surgery after coronary artery bypass grafting has various risk factors related to median re-sternotomy. It is particularly essential to avoid damage to the living graft. We successfully performed aortic valve replacement via right parasternal thoracotomy in a patient who had undergone coronary artery bypass grafting.Case presentationAn 80-year-old man who had undergone coronary artery bypass grafting was referred to our hospital for syncope caused by severe aortic valve stenosis. He also had a history of pericardiotomy for constrictive pericarditis. His left internal thoracic artery bypass graft was patent. Aortic valve replacement was performed through a small right parasternal thoracotomy during cardiac arrest following cardiopulmonary bypass under moderate hypothermia and hyperkalemia by intermittent selective antegrade cardioplegia. His postoperative course was uneventful.ConclusionAortic valve replacement via right parasternal thoracotomy with moderate hypothermia and hyperkalemia was safe and effective for avoidance of re-sternotomy-related complications.

Bilateral Internal Thoracic Artery Bypass Grafting in a High Risk Population - A Four Year Experience with STS Database Derived Clinical Outcomes

The purpose of this retrospective review was to examine the morbidity and mortality associated with the routine use of skeletonized bilateral internal thoracic arteries (BITA) in coronary bypass surgery (CABG). The current rate of BITA use is reported to be 5% in the US. The literature reflects an increased incidence of wound complications, especially in obese, diabetic, and female patients. Our policy has been to use skeletonized BITA in patients regardless of comorbidities. Using the Society of Thoracic Surgery (STS) database, the postoperative markers of prolonged ventilation (PV), length of stay (LOS), wound infection, death, and 30 day readmission were evaluated for all isolated coronary bypass operations (isocab) to allow comparison of bilateral and single internal thoracic artery (ITA) use during this four year period. The incidence of BITA use was 60%. The groups had similar comorbities and postop complications were similar regardless of single or bilateral thoracic artery use. Specifically, there were no wound complications in the BITA group. Adjuncts such as ITA skeletonization, platelet rich plasma, negative pressure wound dressing, and absence of bone wax were utilized in all cases. The added expense is justified to allow the expanded use of BITA.

Invited Commentary

Invited Commentary

Maximal blood flow acceleration analysis in the early diastolic phase for in situ internal thoracic artery bypass grafts: a new transit-time flow measurement predictor of graft failure following coronary artery bypass grafting.

Maximal graft flow acceleration (max df/dt) determined by transit-time flowmetry (TTFM) in the diastolic phase was assessed as a possible predictor of graft failure in coronary artery bypass patients. Max df/dt was retrospectively measured in 57 in situ left internal thoracic artery grafts. TTFM data were fitted to a 5-polynomial curve, which was derived from the first-derivative curve to measure max df/dt (5-polymial max df/dt). Abnormal TTFM was defined as a mean flow of <15 ml/min, pulsatility index of >5 or diastolic filling ratio of <50%. Postoperative coronary angiography (CAG) or multidetector computed tomography (MDCT) was performed within 1 year after surgery. The grafts were classified into four groups: Normal TTFM/Patent MDCT/CAG (N/P), Normal TTFM/Failing MDCT/CAG (N/F), Abnormal TTFM/Patent MDCT/CAG (Ab-N/P) and Abnormal TTFM/Failing MDCT/CAG graft (Ab-N/F). By TTFM, 34 grafts were normal, 5 of which were occluded on CAG, and 23 grafts were abnormal, six of which were occluded on CAG. There were significant differences in 5-polynomial max df/dt between each group pair (P < 0.05, Mann-Whitney U-test) except for the N/F:Ab-N/P group pair; especially, 5-polynomial max df/dt was significantly lower in the Ab-N/F group compared with the other groups (Ab-N/F: 0.89 ± 0.41 vs N/P: 4.74 ± 3.18, N/F: 2.23 ± 0.65, Ab-N/P: 2.70 ± 1.31 ml/s(2), P < 0.01, Mann-Whitney U-test). The sensitivity and specificity of 5-polynomial max df/dt were, respectively, 72.7 and 80.4% (cut-off value, 1.918 ml/s(2)) for all grafts and 100 and 88.2% (cut-off value, 1.273 ml/s(2)) for abnormal TTFM grafts. The TTFM 5-polymial max df/dt value in the early diastolic phase may be a promising predictor of future graft failure.

Sequential Internal Thoracic Artery Bypass Is Safe but Does Not Improve Survival

The benefit of adding an internal thoracic artery (ITA) sequential bypass to single or bilateral ITA graft to improve arterial revascularization is not established. The goal of this study is to evaluate the safety and the potential benefit of ITA sequential bypass in coronary artery surgery. We retrospectively reviewed a cohort of 1,400 consecutive, prospectively followed patients who underwent off-pump coronary artery bypass surgery for multivessel disease between September 1996 and November 2007 at the Montreal Heart Institute. Among them, 1,315 (93.9%) patients had 2- or 3-vessel disease and received at least 1 ITA graft. The following 4 groups were investigated: group 1, single ITA grafting alone (n=758); group 2, single ITA+sequential grafting (n=151); group 3, bilateral ITA grafting alone (n=308); and group 4, bilateral ITA+sequential grafting (n=98). Mean follow-up was 63±33 months and completed in 97% of the cohort. Single ITA patients were older, had more diabetes, chronic obstructive pulmonary disease, peripheral vascular disease, emergency surgery, and heart failure. The rates of complete revascularization, conversion to cardiopulmonary bypass, perioperative mortality, and myocardial infarction were similar in all groups. After correcting for risk factors, better overall, cardiac, and major adverse cardiac event (MACE)-free survival were observed in the bilateral ITA groups compared with the single ITA groups. Adding sequential ITA bypass grafting did not significantly impact survival or MACE-free survival. In our series, bilateral ITA grafting improved overall and MACE-free survival. Adding a sequential ITA bypass grafting was safe but did not add significant benefit in off-pump coronary artery bypass surgery.

A meta-analysis of adjusted hazard ratios from 20 observational studies of bilateral versus single internal thoracic artery coronary artery bypass grafting

In 2001, a landmark meta-analysis of bilateral internal thoracic artery (BITA) versus single internal thoracic artery (SITA) coronary artery bypass grafting for long-term survival included 7 observational studies (only 3 of which reported adjusted hazard ratios [HRs]) enrolling approximately 16,000 patients. Updating the previous meta-analysis to determine whether BITA grafting reduces long-term mortality relative to SITA grafting, we exclusively abstracte, then combined in a meta-analysis, adjusted (not unadjusted) HRs from observational studies. MEDLINE and EMBASE were searched until September 2013. Eligible studies were observational studies of BITA versus SITA grafting and reporting an adjusted HR for long-term (≥4 years) mortality as an outcome. Meta-regression analyses were performed to determine whether the effects of BITA grafting were modulated by the prespecified factors. Twenty observational studies enrolling 70,897 patients were identified and included. A pooled analysis suggested a significant reduction in long-term mortality with BITA relative to SITA grafting (HR, 0.80; 95% confidence interval, 0.77 to 0.84). When data from 6 pedicled and 6 skeletonized internal thoracic artery studies were separately pooled, BITA grafting was associated with a statistically significant 26% and 16% reduction in mortality relative to SITA grafting, respectively (P for subgroup differences=.04). A meta-regression coefficient was significantly negative for the proportion of men (-0.00960; -0.01806 to -0.00114). Based on an updated meta-analysis of exclusive adjusted HRs from 20 observational studies enrolling more than 70,000 patients, BITA grafting seems to significantly reduce long-term mortality. As the proportion of men increases, BITA grafting is more beneficial in reducing mortality.

Thermal damage of internal thoracic artery and ultra high radiofrequency

The gold standard in left anterior descending branch coronary artery surgery is performing an internal thoracic artery (ITA)bypass.Seventy-four ITA specimens were divided into two groups depending on device used for harvesting (radiofrequency-knife (RF) or electrocauter (EC)). Demonstrated results suggest that the radiosurgery in comparison to conventional electrocautery could reduce thermal damage to the endothelial layer of ITA, compared to the conventional electrocautery and potentially optimize the quality of ITA bypass grafts.

Coronary steal phenomenon due to ipsilateral upper extremity arteriovenous fistula in a patient with internal thoracic artery bypass graft: an alternative treatment strategy

Coronary steal phenomenon due to ipsilateral upper extremity arteriovenous fistula in a patient with internal thoracic artery bypass graft: an alternative treatment strategy

Midterm Results of Beating Heart Coronary Bypass Surgery for Non-left Internal Thoracic Artery Anastomosis According to Grafting Design and Implications of Intraoperative Flow Characteristics on Graft Patency

The aim of the present study was to investigate the midterm patency of coronary artery bypass grafting (CABG) surgery according to the grafting design and intraoperative flow characteristics. Between March 2007 and July 2008, 218 beating heart CABG patients were prospectively divided into two groups according to the non-left internal thoracic artery (LITA) bypass grafting design; Group I (n = 161, aorta-saphenous vein) and Group II (n = 57, LITA-radial artery composite grafting). Preoperative patient characteristics and the additive EuroSCORE were similar between the two groups (p = 0.82). Mean flow (mL/min) and pulsatility index were measured intraoperatively and coronary multidetector computed tomography (MDCT) was performed immediately and 1 year postoperatively. For the non-LITA bypasses, the mean flow was significantly greater in group I than in group II (27.9 ± 17.7 mL/min vs. 17.6 ± 12.6 mL/min, p < 0.001). Uni- and multivariate analysis showed the grafting design (group I) to be the only predictive factor for the favorable midterm patency of the non-LITA grafts (p < 0.001). There were no significant intergroup differences in the incidence of complications including that of stroke or death in the immediate postoperative period. A total of four patients had cerebral events: three in group I (1.87%) and one in group II (1.75%). The overall rates of freedom from graft occlusion for the non-LITA to LAD bypasses at 100, 200, and 300 days were 99, 98, and 89%, respectively, in group I, and 95, 88, and 70%, respectively, in group II (P < 0.01). Overall freedom from graft occlusion for LITA to LAD bypasses showed no significant differences between the two groups (98 vs. 93%, p = 0.053). The results suggest superior intraoperative flow characteristics of the direct aorta-saphenous vein bypass grafting design to be attributable for its favorable patency results.

Cardiovascular System Modeling

Cardiovascular System Modeling

Impact of Competitive Flow on Hemodynamics in Coronary Surgery: Numerical Study of ITA-LAD Model

Competitive flow from native coronary artery is considered as a major factor in the failure of the coronary artery bypass grafts. However, the physiological effects are not very clear. The aim is to research the impact of competitive flow caused by different left anterior descending (LAD) artery stenosis degrees on hemodynamics in internal thoracic artery (ITA) bypass graft. An idealized ITA-LAD model was built in CAD tools. The degree of the competitive flow was divided into five classes according to different LAD stenosis degrees: higher (no stenosis), secondary (30% stenosis), reduced (50% stenosis), lower (75% stenosis) and no competitive flow (fully stenosis). Finite volume method was employed for the numerical simulation. The flow velocity distributions, wall shear stress and oscillatory shear index were analyzed. Results showed that higher competitive flow in the bypass graft would produce unbeneficial wall shear stress distribution associating with endothelial dysfunction and subsequent graft failure. The coronary bypass graft surgery was preferred to be carried out when the LAD stenosis was higher than 75%.

Long-term internal thoracic artery bypass graft patency and geometry assessed by multidetector computed tomography

The left internal thoracic artery (LITA) undergoes vascular remodelling when used for coronary artery bypass grafting. In this study we tested the hypothesis that the extent of the LITA remodelling late after coronary artery bypass grafting assessed by multidetector computed tomography is related to the severity of stenosis in the native coronary vessel. One hundred and forty-two patients who had undergone coronary artery bypass grafting including implantation of LITA as conduit to the left anterior descending artery were studied 5 years after surgery. Arterial graft patency and geometry was assessed with 64-slice multidetector computed tomography. Quantitative volumetric assessment of the LITA was performed to measure the average vessel lumen area (mm(2)/m(2)). The native coronary vessel subtended by the LITA was evaluated by multidetector computed tomography and defined as a high-grade stenosis patient group, when the diameter stenosis was >70% and an intermediate grade stenosis patient group when <70%. Among patients with intermediate-grade stenosis of the native vessel 11 out of 65 patients (17%) had a totally occluded LITA, as opposed to none among the 77 patients with a high-grade stenosis. In patients with intermediate-grade stenosis of the proximal native vessel, the LITA lumen area was 4.9 compared to 5.3 mm(2)/m(2) in patients with a high-grade stenosis of the proximal native vessel (P = 0.0043). Lumen area of the LITA when used as a conduit in patients with coronary artery disease seems to be inversely correlated with the severity of disease in the native coronary vessel proximal to the anastomosis. Volumetric vessel multidetector computed tomography appears to be useful for evaluation of coronary bypass remodelling.

Early Failure of Coronary Artery Bypass Grafts: An Albumin Cross-Linked Glutaraldehyde (BioGlue) Related Complication

Bioglue which constitutes albumin cross linked with glutaraldehyde (ACLG) produced by Cryolife, Inc, Kennesaw, GA was introduced as a better alternative to GRF glue with less tissue necrosis. We report a case of a 69-year-old male who developed stenosis of his saphenous vein and internal thoracic artery bypass grafts, requiring re-do coronary artery bypass grafting. Both fibrotic narrowing were in close proximity to the site of Bioglue application and appears to be a reaction to the glue. The advent of ACLG has facilitated surgery; however, this case highlights a potential side effect, emphasizing the judicious use of this hemostatic agent in patients.

Coronary Artery Bypass Surgery Versus Percutaneous Coronary Artery Intervention in Patients on Chronic Hemodialysis: Does a Drug-Eluting Stent Have an Impact on Clinical Outcome?

Coronary revascularization methods continue to be refined, and the emergence of the drug-eluting stent (DES) has especially changed clinical practice related to ischemic heart disease. For chronic hemodialysis (HD) patients, however, the impact of DES on clinical outcome is yet to be determined. Forty-six consecutive chronic HD patients who underwent myocardial revascularization in our institute were retrospectively reviewed. Twenty-eight patients underwent coronary artery bypass surgery (CABG) and 18 patients underwent percutaneous coronary artery intervention (PCI). Patient characteristics were similar between the two groups. In the CABG group, bilateral internal thoracic artery (ITA) bypass grafting was performed in 27 patients and off-pump CABG was performed in 20 patients. In the PCI group, a DES was used in 12 patients. The number of coronary vessels treated per patient was higher in the CABG group (CABG: 4.25 +/- 1.32 vs. PCI: 1.44 +/- 0.78; p < 0.001). Two-year survival rates were similar between the two groups (CABG: 94.1% vs. PCI: 73.9%; p = 0.41), but major adverse cardiac event-free survival (CABG: 85.9% vs. PCI: 37.1%; p = 0.001) and angina-free survival (CABG: 84.9% vs. PCI: 28.9%; p < 0.001) rates were significantly higher in the CABG group. The one-year patency rate for the CABG grafts was 93.3% (left ITA: 100%, right ITA: 84.6%, sapenous vein: 90.9%, gastro-epiploic artery: 100%), and six-month restenosis rate for PCI was 57.1% (balloon angio-plasty: 75%, bare metal stent 40%, DES: 58.3%). Even in the era of DES, clinical results favored CABG. The difference in clinical results is due to the sustainability of successful revascularization.

Does Bilateral Pedicle Internal Thoracic Artery Harvest Increase the Risk of Mediastinitis?

PurposeBilateral in situ internal thoracic artery (ITA) bypassing may result in excellent myocardial revascularization without increasing the risk of deep sternal wound infection. Although there have been concerns with the use of pedicled bilateral ITA, the risk of infection may not be greater than the use of skeletonized ITA.Materials and MethodsThe present study was retrospectively undertaken to determine if pedicled BITA grafts are associated with a higher risk of sternal wound complications. A total of 207 patients who underwent bilateral ITA bypasses with or without existing diabetes mellitus, and 162 patients of those received bilateral pedicled ITA and 98 patients received unilateral ITA bypass grafts.ResultsNo sternal wound complications were noted in either the bilateral ITA or unilateral left ITA groups.ConclusionBilateral pedicled ITA harvesting was not associated with a greater incidence of infectious sternal complications compared to patients receiving unilateral ITA bypass grafts.