Single Internal Thoracic Artery Grafting Research Articles

EARLY RESULTS OF MINIMALLY INVASIVE CORONARY ARTERY BYPASS GRAFTING

Abstract Coronary artery bypass grafting (CABG) is the benchmark in elective revascularization for Coronary Artery Disease (CAD), particularly for complex or multivessel CAD, left main coronary involvement, diabetes, or impaired heart function. Traditional CABG, via median sternotomy using cardiopulmonary bypass (CPB), has limitations like CPB–related morbidity and sternal complications. Alternatives like Minimally Invasive Cardiac Surgery (MICS CABG) and Hybrid Revascularization (HR) aim to address these drawbacks. We present a series of 215 consecutive patients (mean age 67±9 years, 27.9% females, EuroSCORE II 1.5±1.3%) between 2017–2023 who underwent elective minimally invasive surgical revascularization. Among the cohort, 164 (76.3%) had Minimally Invasive Direct Coronary Artery Bypass (MIDCAB) via anterolateral left mini–thoracotomy (ALMT) at the fifth intercostal space (IS), with 140 (85.4%) receiving a single left internal thoracic artery (LITA) graft to the left anterior descending (LAD) artery and 24 (14.6%) an additional distal anastomosis. Thirty–four (20.7%) had HR via percutaneous coronary intervention (PCI) on the right coronary artery (RCA). Of the total cohort, 35/215 patients (16.3%) underwent multivessel MICS CABG via ALMT, with mean 2.3±0.5 distal anastomoses using LITA, right ITA, radial artery, or saphenous vein. Heart manipulation was via a subxiphoid device. Four MICS CABG patients (11.4%) had HR. More than half of MICS CABG cases were performed with planned peripheral CPB, without cross–clamping the Aorta. Of the total cohort, 16/215 patients (7.4%) received MICS CABG in an endoscopic fashion, using 3D thoracoscopy for LITA and RITA harvesting via bilateral ports in the 2nd, 3rd, and 4th IS, employing peripheral CPB and aortic clamping by Chitwood clamp at the second IS, with cardioplegia delivery via a 4 cm right anterior MT. Distal anastomoses were performed via left anterior MT, with easy subxiphoid manipulation of the emptied heart. Transit time flowmetry was used in all cases. Conversion to sternotomy was needed in 3 cases, all were MIDCAB. Thirty–day mortality was 1.4%, median ventilation was 4 [2–5] hours, and Intensive Care Unit–stay was 1 [1–2] days. All patients received graft evaluation via computerized tomography before hospital discharge. Mean follow–up was 2.9±1.9 years (max 5 years), with no deaths and 4 (1.9%) requiring follow–up PCI. MICS CABG is a promising future technique for heart revascularization by dedicated teams.

Long-term results following off-pump coronary-artery bypass grafting in left ventricular dysfunction.

Severe left ventricular (LV) dysfunction is an independent risk factor for early and long-term mortality after coronary-artery bypass grafting (CABG). Off-pump CABG (OPCAB) significantly reduces the early incidence of major complications in high-risk patients. Moreover, bilateral internal thoracic artery (BITA) grafting after CABG is associated with improved long-term outcomes. We aimed to evaluate the impact of multivessel OPCAB with BITA grafting for complete revascularization on postoperative and long-term outcomes in patients with low LV ejection fraction (EF). We included 121 patients with EF ≤ 30.0% who underwent isolated multivessel OPCAB (average LVEF, 24.8%) between April 2007 and December 2019. Sixty-six patients received BITA grafts, while 55 had single internal thoracic artery (SITA) grafts. We conducted multivariate analyses to examine the correlation between perioperative data and late mortality rate. The early mortality rate was 1.65%. After excluding in-hospital mortality cases, we performed long-term follow-up of 119 patients. Early postoperative echocardiography showed significant LVEF improvement in 89 (75.2%) patients. However, LVEF remained ≤ 30.0% in 30 (24.8%) patients. We recorded 15 and 30 cases of cardiac death and cardiac events, respectively, during the long-term follow-up period. Postoperative LVEF ≤ 30.0% (P < 0.01) and no use of BITA grafting (P = 0.03) were significant predictors of cardiac death and events; moreover, hemodialysis was a significant predictor of all-cause mortality rather than cardiac death. Multivessel OPCAB in patients with severe LV dysfunction was associated with acceptable in-hospital mortality and early postoperative improvement in LV function. Additionally, OPCAB with BITA grafting may provide long-term benefits with respect to cardiac death and events. However, the long-term benefits were significantly limited in patients without early postoperative improvement in LV function and patients with chronic hemodialysis.Clinical registration number: 5590 (14/5/2020 Tokyo Women's Medical University).

Single versus bilateral internal thoracic artery grafting in patients with impaired renal function.

The optimal strategy for surgical revascularization in patients with impaired renal function is inconclusive. We compared early and late outcomes between bilateral internal thoracic artery (BITA) and single ITA (SITA) grafting in patients with renal dysfunction. This is a retrospective analysis of all the patients with multivessel disease and impaired renal function (estimated glomerular filtration rate <60mL/min/1.73m2) who underwent isolated coronary artery bypass graft (CABG) in our center during 1996-2011, utilizing either BITA or SITA revascularization. Of the 5301 patients with multivessel disease who underwent surgical revascularization during the study period, 391 were with impaired renal function: 212 (54.2%) underwent BITA, 179 (45.8%) underwent SITA. Patients who underwent BITA were less likely to have comorbidities. Statistically significant differences were not observed between the BITA and SITA groups in 30-day mortality (5.6% vs. 9.0%, p = 0.2) and in rates of early stroke, myocardial infarction, and sternal infection (4.5% vs. 6.1%, p = 0.467; 1.7% vs. 2.8%, p = 0.517; and 2.2% vs. 5.7%, p = 0.088, respectively). Long-term survival of the BITA group was better: median 8.36 vs. 4.14 years, p<0.001. In multivariable analysis, BITA revascularization was associated with decreased late mortality (HR = 0.704, 95% CI: 0.556-0.89, p = 0.003). In analysis of a matched cohort (134 pairs), early outcomes did not differ between the groups; however, in multivariable analysis, BITA revascularization was associated with decreased late mortality ‎‎(HR = 0.35 (95%CI 0.18-0.68), p = 0.002)‎. BITA revascularization did not impact early outcome in patients with CRF, but demonstrated a significant protective effect on long-term survival ‎in the unmatched and matched cohorts.

Off-pump bilateral internal thoracic artery grafting in patients with left main coronary artery disease

BackgroundTo compare postoperative outcomes in patients with left main coronary artery disease who underwent off-pump isolated coronary artery bypass grafting for multivessel disease using either skeletonized bilateral or single internal thoracic artery (ITA).MethodsAmong 1583 patients who underwent isolated coronary artery bypass grafting (CABG) in our hospital between 2002 and 2022, 604 patients with left main coronary artery disease underwent single (n = 169) or bilateral (n = 435) ITA grafting. We compared postoperative outcomes between the two groups after adjusting preoperative characteristics using inverse probability of treatment weighting.ResultsAfter adjustment using inverse probability of treatment weighting method, the sum of weights was 599.74 in BITA group and 621.64 in SITA group. There was no significant difference in postoperative deep sternal wound infection (p = 0.227) and 30-day mortality (p = 0.612). Follow-up was completed in 98.7% (596/604) of the patients, and the mean follow-up duration was 6.7 years. At 10 years, the overall survival following bilateral versus single ITA grafting was 71.2% and 60.6%, respectively (log-rank test, p = 0.040), and freedom from major adverse cardiac and cerebrovascular events (MACCE) was 63.3% and 46.3%, respectively (log-rank test, p = 0.008). In multivariate Cox proportional hazard models, bilateral ITA grafting was significantly associated with a lower risk of all-cause death (hazard ratio [HR]: 0.706, 95% confidence interval [CI]: 0.504–0.987; p = 0.042) and MACCE (HR: 0.671, 95% CI: 0.499–0.902; p = 0.008).ConclusionsBilateral skeletonized ITA grafting is associated with lower rates of all-cause death and MACCE than single ITA grafting in patients with left main coronary artery disease undergoing off-pump CABG.

Coronary artery bypass grafting using bilateral internal thoracic arteries in patients with diabetes and obesity: A systematic review and meta-analysis

BackgroundPatients with diabetes and obesity are at higher risk of adverse long-term outcomes following coronary artery bypass grafting. The use of bilateral internal thoracic arteries (BITA) can potentially offer survival benefit in higherrisk patientscompared to single internal thoracic artery (SITA), but BITAisnotroutinelyused due tolack of clear evidence of efficacy andconcerns over sternal wound complications. MethodsMedline, Embase and the Cochrane Library were searched forstudies comparing the efficacy and safety of BITA and SITA grafting in patients with diabetes and obesity. Meta-analysis of mortality and sternal wound complications was performed. ResultsWe identified eight observational and ten propensity matched studies, and one RCT, comparing BITA and SITA which included patients with diabetes (n = 19,589); two propensity matched studies and one RCT which included patients with obesity (n = 6,972); mean follow up was 10.5 and 11.3 years respectively. Meta-analysis demonstrated a mortality reduction for BITA compared to SITA in patients with diabetes (risk ratio [RR] 0.79; 95% confidence interval [CI] 0.70–0.90; p = 0.0003). In patients with obesity there was a non-significant reduction in mortality in the BITA group (RR 0.73, 95% CI 0.47–1.12; p = 0.15). There was a significantly higher rate of sternal wound complications following BITA observed in patients with diabetes (RR 1.53, 95% CI 1.23–1.90; p = 0.0001) and obesity (RR 2.24, 95% CI 1.63–3.07; p < 0.00001). ConclusionsBITA is associated with better long-term survival in patients with diabetes. The effects of BITA grafting in patients with obesity are uncertain. BITA is associated with higher rates of sternal wound complications compared to SITA in both patients with diabetes and obesity.

Bilateral Versus Single Internal Thoracic Artery Grafting for Elderly Patients Undergoing Coronary Revascularisation for Multivessel Disease: A Systematic Review and Meta-Analysis

International guidelines suggest that multiple arterial grafting is preferred for young patients undergoing coronary artery bypass graft (CABG) surgery for multivessel disease. Limited data exist comparing outcomes of single internal thoracic artery (SITA) with bilateral internal thoracic artery (BITA) grafting in elderly patients.

Bilateral versus Single Internal Thoracic Artery Grafting Strategies Supplemented by Radial Artery Grafting.

It is unclear if a second or third arterial graft can improve clinical outcomes in coronary artery bypass graft surgery. We compared the outcomes of bilateral internal thoracic artery (BITA) plus radial artery (RA) grafting versus left internal thoracic artery (LITA) plus RA grafting after off-pump coronary artery bypass grafting. Between January 2009 and December 2020, a total of 3007 patients with three-vessel coronary artery disease who underwent off-pump coronary artery bypass were analyzed. Among them, 971 patients received total arterial grafting using LITA. We divided the patients into two groups [group A, BITA+RA grafting (n=227) and group B, LITA+RA grafting (n=744)], and compared the survival and major adverse cardiac and cerebrovascular event (MACCE) rates between the two groups at 10 years. After risk adjustment with inverse probability treatment weighting methods, the freedom from all-cause mortality was 93.1% and 88.3% in groups A and B, respectively (p=0.140). The freedom from MACCE rates were 68.3% and 89.0%, respectively (p<0.0001). LITA plus RA grafting [hazard ratio (HR): 1.3, 95% confidence interval (CI): 1.05-2.37, p=0.025] and incomplete revascularization (HR 1.2, 95% CI: 0.70-2.15, p=0.046) were significant risk factors for MACCEs in multivariable Cox regression analysis. The rates of MACCEs were lower with LITA plus RA grafting than with BITA plus RA grafting in total arterial revascularization. Furthermore, complete revascularization improved long-term outcomes following total arterial grafting.

Meta-Analysis of Bilateral Versus Single Internal Thoracic Artery Grafting in Patients ≥70 Years of Age

The optimal choice of graft material in patients ≥70years of age undergoing coronary artery bypass grafting remains unknown. A systematic review of literature was conducted by searching PubMed, Embase, Web of Science, and Cochrane Library databases for original publications that compared bilateral internal thoracic artery (BITA) grafting with single internal thoracic artery grafting in patients ≥70years of age. Data were extracted by 2 independent investigators and meta-analyzed with the use of random effects. A total of 10 studies, including 11,185 patients, met the inclusion criteria. No differences in early mortality and morbidity, with the exemption of sternal wound complications which were more frequently observed in the BITA group (odds ratio 1.72, 95% 1.00 to 2.96 confidence interval [CI], p=0.05; propensity score-matched population odds ratio 1.58, 95% CI 1.09 to 2.29, p=0.02), were observed. Overall survival was superior in the overall patient population (hazard ratio [HR] 0.76, 95% CI 0.66 to 0.86, p <0.001), after applying a blanking period of 3months to the overall patient population (HR 0.77, 95% CI 0.64 to 0.92, p=0.005) as well as in the matched population (HR 0.72, 95% CI 0.58 to 0.89, p=0.002); in all cases, a benefit was readily seen within a few years after surgery. The difference in freedom from major adverse cardiac and cerebrovascular events failed to reach statistical significance (overall patient population HR 0.55, 95% CI 0.27 to 1.13, p=0.10; matched population HR 0.52, 95% CI 0.23 to 1.16, p=0.11). In conclusion, BITA grafting can be safely performed in patients ≥70years of age as late clinical benefits are expected to manifest themselves readily within a few years after surgery.

Bilateral internal thoracic artery coronary grafting: risks and benefits in elderly patients.

Whether bilateral internal thoracic artery (BITA) grafting benefits elderly patients in coronary artery bypass grafting (CABG) remains unclear since they tend to have a limited life expectancy and severe comorbidities. We aim to evaluate the outcomes of BITA vs. single internal thoracic artery (SITA) grafting in elderly patients. A meta-analysis was performed by database searching until May 2021. Studies comparing BITA and SITA grafting among elderly patients were included. One randomized controlled trial, nine propensity score matching, and six unmatched studies were identified, with a total of 18146 patients (7422 received BITA grafting and 10724 received SITA grafting). Compared with SITA grafting, BITA grafting had a higher risk of deep sternal wound infection (DSWI) [odds ratio: 1.67; 95% confidence interval (CI): 1.22-2.28], and this risk could not be significantly reduced by the skeletonization technique. Meanwhile, BITA grafting was associated with a higher long-term survival [hazard ratio: 0.83; 95% CI: 0.77-0.90], except for the octogenarian subgroup. Reconstructed Kaplan-Meier survival curves revealed 4-year, 8-year, and 12-year overall survival rates of 85.5%, 66.7%, and 45.3%, respectively, in the BITA group and 79.3%, 58.6%, and 34.9%, respectively, in the SITA group. No significant difference was observed in early mortality, perioperative myocardial infarction, perioperative cerebral vascular accidents, or re-exploration for bleeding. Compared with SITA grafting, BITA grafting could provide a long-term survival benefit for elderly patients, although this benefit remained uncertain in octogenarians. Meanwhile, elderly patients who received BITA were associated with a higher risk of DSWI and such a risk could not be eliminated by the skeletonization technique.

Additional survival benefit of bilateral in situ internal thoracic artery grafting with composite radial artery graft in total arterial off-pump coronary artery bypass grafting

ObjectiveThis study aimed to elucidate whether the use of bilateral internal thoracic arteries (BITAs) confers additional survival benefits compared with a single internal thoracic artery (SITA) in total arterial grafting with the radial artery. MethodsBetween 2002 and 2016, 617 patients underwent a bilateral in situ internal thoracic artery grafting with the radial artery as a composite I-graft (BITA-I group) and 516 patients underwent single in situ internal thoracic artery grafting with the radial artery as a composite Y-graft (SITA-Y group). All anastomoses were performed without cardiopulmonary bypass and aortic manipulation. Propensity score matching was performed to adjust covariates and compared the outcomes between the 2 groups. Subanalysis was also performed to evaluate the effects of the BITA-I group on survival according to the covariates using Cox proportional hazards regression analysis. ResultsPropensity score matching yielded 348 well-matched pairs. Early postoperative outcomes were similar in the 2 groups. The BITA-I group showed significantly better survival than the SITA-Y group (79.3% vs 70.2% at 10 years, P = .015). The subanalysis revealed a significantly better survival in the BITA-I group among overall patients (hazard ratio, 0.68; 95% confidence interval, 0.49-0.93). There was a significant positive effect on survival in the BITA-I group among patients without comorbidities or those aged <77 years. ConclusionsBITA grafting with the radial artery provides better long-term survival than SITA grafting with the radial artery, which is enhanced among patients aged <77 years with minimum comorbidities.

Bilateral Internal Thoracic Artery Grafting Improves Survival for Severe Left Ventricular Dysfunction and Diabetes.

In patients with severe left ventricular (LV) dysfunction requiring coronary artery bypass grafting (CABG), the association between diabetic status and outcomes after surgery, as well as with survival benefit following bilateral internal thoracic artery (ITA) grafting, remain largely unknown.Methods and Results:Patients (n=188; mean [±SD] age 67±9 years) with LV ejection fraction ≤40% who underwent isolated initial CABG were classified into non-diabetic (n=64), non-insulin-dependent diabetic (NIDM; n=74), and insulin-dependent diabetic (IDM; n=50) groups. During follow-up (mean [±SD] 68±47 months), the 5-year survival rate was 84% and 65% among non-diabetic and diabetic patients, respectively (P=0.034). After adjusting for all covariates, both NIDM and IDM were associated with increased mortality, with hazard ratios (HRs) of 1.9 (95% confidence interval [CI] 1.0-3.7; P=0.049) and 2.4 (95% CI 1.2-4.8; P=0.016), respectively. Among non-diabetic patients, there was no difference in the 5-year survival rate between single and bilateral ITA grafting (86% vs. 80%, respectively; P=0.95), whereas bilateral ITA grafting increased survival among diabetic patients (57% vs. 81%; P=0.004). Multivariate analysis revealed that bilateral ITA was significantly associated with a decreased risk of mortality (HR 0.3; 95% CI 0.1-0.8; P=0.024). NIDM and IDM were significantly associated with worse long-term clinical outcome after CABG for severe LV dysfunction. Bilateral ITA grafting has the potential to improve survival in diabetic patients with severe LV dysfunction.

Multi-arterial Coronary Grafting

Arterial conduits, especially internal thoracic arteries (ITAs), are rarely affected by intimal hyperplasia or atherosclerosis, major contributors to early and late vein graft failure. Improved survival and freedom from reintervention with multi-arterial grafting (MAG) are reported in large observational studies, particularly when more than one anatomically important coronary territory is supplied. Several grafting configurations are possible depending on conduit and target characteristics, with the left ITA to the left anterior descending (LITA-LAD) typically being the cornerstone around which the rest of the conduits are constructed. The right ITA (RITA) or radial artery (RA) is used to bypass the second most important target after the LAD. The fundamentals of MAG depend on thorough preoperative evaluation, meticulous surgical technique and intraoperative flow assessment. Pitfalls to avoid include tension in short conduits or kinks in longer ones, poor ITA inflow, competitive native and graft flow, flow imbalance between segments of a composite graft, and sequentially grafting deep intramyocardial targets. Versatility and flexibility are critical in mitigating difficulties or potential complications in MAG. Refinements in complex bilateral ITA (BITA) and RA grafting require a deliberate iterative process that ideally incorporates dedicated training and mentorship by experienced MAG surgeons. Arterial conduits, especially internal thoracic arteries (ITAs), are rarely affected by intimal hyperplasia or atherosclerosis, major contributors to early and late vein graft failure. Improved survival and freedom from reintervention with multi-arterial grafting (MAG) are reported in large observational studies, particularly when more than one anatomically important coronary territory is supplied. Several grafting configurations are possible depending on conduit and target characteristics, with the left ITA to the left anterior descending (LITA-LAD) typically being the cornerstone around which the rest of the conduits are constructed. The right ITA (RITA) or radial artery (RA) is used to bypass the second most important target after the LAD. The fundamentals of MAG depend on thorough preoperative evaluation, meticulous surgical technique and intraoperative flow assessment. Pitfalls to avoid include tension in short conduits or kinks in longer ones, poor ITA inflow, competitive native and graft flow, flow imbalance between segments of a composite graft, and sequentially grafting deep intramyocardial targets. Versatility and flexibility are critical in mitigating difficulties or potential complications in MAG. Refinements in complex bilateral ITA (BITA) and RA grafting require a deliberate iterative process that ideally incorporates dedicated training and mentorship by experienced MAG surgeons. Corrigendum: Multi-arterial Coronary GraftingOperative Techniques in Thoracic and Cardiovascular SurgeryVol. 27Issue 4PreviewThe authors regret that in the article “Multi-arterial Coronary Grafting” by Rami Akhrass and Faisal G. Bakaeen in the Summer 2022 issue (27(2):126-146, 2022; https://doi.org/10.1053/j.optechstcvs.2021.09.001 ), (Figures 2 and 10) included an error with the course of the right internal thoracic artery (RITA). The corrected figures are included on the next 2 pages. Figure 2 was used as the cover image for the issue. In both Figures 2 and 10, the RITA should be anterior to the superior vena cava and posterior to the pulmonary artery. Full-Text PDF Commentary: Multiple Arterial Grafting for Coronary Artery Bypass Surgery: Choosing the Right Conduits for The Right Vessels for The Right PatientsOperative Techniques in Thoracic and Cardiovascular SurgeryVol. 27Issue 2PreviewDespite the known increased patency of arterial versus saphenous vein graft (SVG) conduits for Coronary Artery Bypass Graft (CABG) surgery, a recent Society of Thoracic Surgery (STS) national database study showed that while a single internal thoracic artery (SITA) graft was used in 89.4% of CABG patients, only 10.6% received multiple arterial grafts (MAG) and only 4.9% had bilateral internal thoracic artery grafts (BITA).1 What are the factors that have discouraged surgeons from embracing MAG and BITA grafting? In a 2018 national survey from the United Kingdom, almost one third of surgeons cited the lack of evidence in favor of MAG and BITA as a limiting factor for not adopting these techniques in their practices. Full-Text PDF Commentary: Time to Set New Standards for Coronary Bypass Surgery?Operative Techniques in Thoracic and Cardiovascular SurgeryVol. 27Issue 2PreviewAsk any cardiac surgeon who started their training in 90s, and you'll find that many of them, at some point, must have thought that surgical coronary revascularization was ill-fated. Especially in the mid 2000s, when drug-eluting stents appeared on the market and furtherly improved the outcomes of percutaneous revascularization1... God knew what would come next! History - and clinical trials - proved them wrong: almost 20 years later, coronary artery bypass grafting (CABG) is still the most common procedure in adult cardiac surgery and remains the gold standard for treatment of complex triple vessel disease and left main disease, particularly in younger patients and in case of diabetes or reduced left ventricular function. Full-Text PDF

Impact of Bilateral versus Single Internal Thoracic Artery Grafting on the Long-Term Survival in Adults: A Systematic Review.

ObjectiveTo analyse the survival of patients who had undergone bilateral internal thoracic artery grafting versus those with single internal thoracic artery grafting from the available literature. Moreover, this study will review the available literature regarding which of the two techniques seems to be the safest with long-term survival and reduced mortality rates.MethodsA literature search of the databases was conducted to retrieve studies that fall under the study design of cohort and randomized controlled clinical trials in English from January 2015 to July 2021. Finally, seven studies were selected: four cohort studies and three other from a randomized trial.ResultsThe cohort studies revealed that bilateral internal thoracic artery grafting is associated with lower mortality rates and better long-term survival outcomes than single internal thoracic artery grafting, while the ART randomized controlled clinical trials showed that there is no significant difference in mortality rates between both the coronary artery bypass grafting techniques. However, all studies concluded that bilateral internal thoracic artery grafting is associated with a higher frequency of deep sternal wound infections.ConclusionThe discrepancy in results between the cohort studies and randomized controlled clinical trial remains persistent. However, the stated advantages of bilateral internal thoracic artery grafting are not strong enough to convince surgeons to alter their practice and the wide magnitude of expectations from the ART study was reckoned as inadequate. This may well be due to the presence of limited criteria for bilateral internal thoracic artery grafting in identifying the impact on survival of extended arterial revascularization, and there is a new colossal expectation from the ongoing randomized trial based on multiple arterial grafting versus single arterial grafting.

Cost-effectiveness of bilateral vs. single internal thoracic artery grafts at 10 years.

AimsUsing bilateral internal thoracic arteries (BITAs) for coronary artery bypass grafting (CABG) has been suggested to improve survival compared to CABG using single internal thoracic arteries (SITAs) for patients with advanced coronary artery disease. We used data from the Arterial Revascularization Trial (ART) to assess long-term cost-effectiveness of BITA grafting compared to SITA grafting from an English health system perspective.Methods and resultsResource use, healthcare costs, and quality-adjusted life years (QALYs) were assessed across 10 years of follow-up from an intention-to-treat perspective. Missing data were addressed using multiple imputation. Incremental cost-effectiveness ratios were calculated with uncertainty characterized using non-parametric bootstrapping. Results were extrapolated beyond 10 years using Gompertz functions for survival and linear models for total cost and utility. Total mean costs at 10 years of follow-up were £17 594 in the BITA arm and £16 462 in the SITA arm [mean difference £1133 95% confidence interval (CI) £239 to £2026, P = 0.015]. Total mean QALYs at 10 years were 6.54 in the BITA arm and 6.57 in the SITA arm (adjusted mean difference −0.01 95% CI −0.2 to 0.1, P = 0.883). At 10 years, BITA grafting had a 33% probability of being cost-effective compared to SITA, assuming a cost-effectiveness threshold of £20 000. Lifetime extrapolation increased the probability of BITA being cost-effective to 51%.ConclusionsBITA grafting has significantly higher costs but similar quality-adjusted survival at 10 years compared to SITA grafting. Extrapolation suggests this could change over lifetime.

Outcomes after coronary artery bypass graft surgery: systematic review and meta-analysis comparing bilateral versus single internal thoracic artery grafts

Abstract Background Patients with diabetes and/or obesity are at higher risk of adverse outcomes following coronary artery bypass grafting (CABG). The use of bilateral internal thoracic arteries (BITA) can potentially offer survival benefit in higher risk patients compared to single internal thoracic artery (SITA) in patients undergoing CABG, but the overall evidence base for BITA has not influenced guidelines, and there are concerns over increased risk of sternal wound complications. Methods We conducted a systematic review of the literature to identify observational studies and randomised controlled trials (RCT) comparing the efficacy (mortality) and safety (sternal wound infection) of BITA and SITA in diabetic and obese patients. Results We identified 18 observational studies and one RCT to obtain data comparing BITA and SITA in 19,589 diabetic patients, and two observational studies and one RCT comparing BITA and SITA in 6972 obese patients. Pooled analysis demonstrated significant mortality benefit of BITA compared to SITA in diabetic patients (risk ratio [RR] 0.79; 95% confidence interval [CI] 0.70, 0.90; Z=3.62, p=0.0003; I2=88%) (Figure 1a). Pooled analysis in obese patients found no significant difference in mortality rates between BITA and SITA (RR 0.73, 95% CI 0.47, 1.12; Z=1.43, p=0.15; I2=78%) (Figure 1b). A significantly higher rate of sternal wound complications following BITA was observed in diabetic (RR 1.53, 95% CI 1.23, 1.90; Z=3.86, p=0.0001; I2=4%) and obese patients (RR 2.24, 95% CI 1.63, 3.07; Z=5.00, p&amp;lt;0.00001; I2=0%). Conclusions BITA is associated with better long-term survival in diabetic patients, but most of the supportive data comes from observational studies. The effects of BITA grafting in patients who are obese is uncertain due to low numbers. BITA is associated with higher rates of sternal wound complications than SITA in both diabetic and obese patients. Further research is needed to understand if BITA has a role in higher risk patients undergoing CABG. Figure 1. Pooled all-cause mortality Funding Acknowledgement Type of funding source: None

Single versus bilateral internal thoracic artery grafting in patients with low ejection fraction.

Coronary artery bypass grafting (CABG) is the standard of care for the treatment of complex coronary artery disease. However, the optimal surgical treatment for patients with reduced left ventricular function with low ejection fraction (EF) is inconclusive. In our center, left-sided coronary grafting with bilateral internal thoracic artery (BITA) is generally the preferred method for surgical revascularization, also for patients with low EF. We compared early and long-term outcomes between BITA grafting and single internal thoracic artery (SITA) grafting in patients with low EF.We evaluated short- and long-term outcomes of all patients who underwent surgical revascularization in our center during 1996 to 2011, according to EF ≥30% and <30%. Univariate and multivariate analyses were performed. In addition, patients who underwent BITA and SITA grafting were matched using propensity score matching.In total, 5337 patients with multivessel disease underwent surgical revascularization during the study period. Of them, 394 had low EF. Among these, 188 underwent SITA revascularization and 206 BITA grafting. Those who underwent SITA were more likely to have comorbidities such as chronic obstructive pulmonary disease, diabetes, congestive heart failure, chronic renal failure, and a critical preoperative condition including preoperative intra-aortic balloon pump insertion.Statistically significant differences were not observed between the SITA and BITA groups in 30-day mortality (8.5% vs 6.8%, P = .55), sternal wound infection (2.7% vs 1.0%, P = .27), stroke (3.7% vs 6.3%, P = .24), and perioperative myocardial infarction (5.9% vs 2.9%, P = .15). Long-term survival (median follow up of 14 years, interquartile range, 11.2–18.9) was also similar between the groups. Propensity score matching (129 matched pairs) yielded similar early and long-term outcomes for the groups.This study did not demonstrate any clinical benefit for BITA compared with SITA revascularization in individuals with low EF.

Bilateral internal thoracic artery grafting in elderly patients: Any benefit in survival?

The purpose of the present study was to compare survival outcomes in propensity score-matched patients aged 70years or greater receiving a bilateral internal thoracic artery graft with patients receiving a single internal thoracic artery graft. Among 4083 consecutive patients with isolated coronary artery bypass grafting who underwent operation between January 2001 and December 2018, we identified 1300 patients aged 70years or greater; of these, 968 received a bilateral internal thoracic artery (bilateral internal thoracic artery group) and 332 received a single internal thoracic artery (single internal thoracic artery group). Propensity score matching was used to reduce the preoperative patient differences. The 10-year survival and postoperative complications were compared between the 2 groups. A Kaplan-Meier curve at 10years of follow-up showed that crude survival was significantly superior in patients with bilateral internal thoracic artery grafts than in patients with single internal thoracic artery grafts (67.0%±2.5% vs 56.0%±3.4%, respectively; P<.016). In the actuarial survival, estimates for propensity score-matched patients with a bilateral internal thoracic artery showed a significantly higher rates of survival than patients with a single internal thoracic artery by the end of follow-up (66.0%±5.3% vs 53.0%±3.9%, respectively; hazard ratio, 0.64; 95% confidence interval, 0.44-0.94; P=.022, univariable Cox Model and multivariable analysis hazard ratio, 0.66; 95% confidence interval, 0.45-0.97; P=.036 Cox model). Postoperative complications were all similar between the single internal thoracic artery and bilateral internal thoracic artery groups. The use of bilateral internal thoracic artery grafting in older patients improves 10-year survival, with similar postoperative morbidity. This surgical technique might have beneficial effects in survival in patients aged more than 70years. Its use could be considered more frequently.

Is the Use of BITA vs SITA Grafting Safe and Beneficial in Octogenarians?

Bilateral internal thoracic artery (BITA) grafting is questionable in octogenarians because of shorter life expectancy and increased risk of perioperative complications. The aim of this study was to examine the safety and effectiveness of performing BITA and single internal thoracic artery (SITA) grafts in patients older than 80 years of age. This study compared outcomes in 201 consecutive octogenarians who underwent isolated BITA grafting with those of 280 consecutive octogenarians who underwent SITA and saphenous vein grafting during 1996 to 2011. Insulin-dependent diabetes, ejection fraction <30, and emergency operations were more common among patients who underwent SITA, and the prevalence of left main coronary artery disease was lower. Propensity score matching was used to control for these differences, thus generating well-matched groups of 190 patients each. There were no significant differences in early mortality between the unmatched groups: 3.2% in the BITA group and 8.6% in the SITA group (P= .12). Rates of sternal wound infection were also similar, 1.5% vs 1.7%, respectively. Differences were not observed in the occurrences of perioperative stroke (3.5% vs 2.5%; P= .999) and myocardial infarction (1.5% vs 3.6%; P= .166). The results were similar for the matched groups. Long-term survival between the unmatched groups and survival between the matched groups were not significantly different. This study shows equal long-term survival for BITA and SITA grafting in octogenarians. BITA is an acceptable alternative to SITA grafting in low-risk octogenarians and in the presence of a calcified aorta or poor-quality saphenous vein graft.

The Power and the Pitfalls of Randomized Clinical Trials

In this issue of The Annals of Thoracic Surgery, the review article by Gaudino and colleagues1Gaudino M. Ruel M. Obadia J.-F. et al.Methodologic considerations on four cardiovascular interventions trials with contradictory results.Ann Thorac Surg. 2021; 111: 690-700Abstract Full Text Full Text PDF PubMed Scopus (7) Google Scholar beautifully illustrates challenges associated with randomized clinical trials (RCTs) in surgery. The authors demonstrated the impact of differences in outcome definitions and patient populations—and potentially open-label design—on study results, calling for agreement on common outcomes definitions and duration of follow-up in study design and the involvement of statistical methodologists in guideline documents. Here, here! RCTs are widely accepted as the most objective method to evaluate treatment effect of an intervention by neutralizing known and unknown confounders. As such they stand at the top of the “evidence pyramid.” However they suffer significant limitations, particularly when related to interventional and operative procedures. First, bias is inescapable. The RCT design addresses “treatment selection bias” but inescapably substitutes “entry selectivity bias.” Despite complaints that the population studied in a given RCT are not representative of “real-world” clinical practice, such entry bias is necessary if one is to accurately study the treatment effect. This is analogous to using inbred mouse strains in basic science or when evaluating a specific pharmacologic agent for example. Appropriately these authors focus on the need to clarify and emphasize the impact of this bias rather than complain about its existence. Indeed they highlight the potential influence of heterogeneity in study population in the MITR-FR trial on study results. In fact in clever hands subtle manipulation of the study population (and other subtleties in RCT study design) can be used to demonstrate equivalence of empty backpacks to parachutes among individuals jumping from aircraft.2Yeh R.W. Valsdottir L.R. Yeh M.W. et al.Parachute use to prevent death and major trauma when jumping from aircraft: randomized controlled trial.BMJ. 2018; 363: k5094Crossref PubMed Scopus (65) Google Scholar The authors also emphasized the impact of differences in composite endpoints, perhaps notoriously including the definitions of their components, on study outcomes. It should be more broadly noted, however, that composite endpoints in all instances are potentially misleading. Used to increase the power of a study, they are commonly odd bedfellows chosen more as a matter of convenience than equivalence. Although repeat revascularization is indeed undesirable and potentially dangerous, would any of us seriously equate it with stroke or death? Among the challenges in surgical RCTs unaddressed by these authors is heterogeneity in the treatment administered (procedure performed). The consequences of this vulnerability is evident in the Arterial Revascularization Trial study, which demonstrated no impact of bilateral internal thoracic artery grafts when analyzed by intention to treat, but the opposite when considered by treatment received.3Taggart D.P. Benedetto U. Gerry S. et al.Arterial Revascularization Trial Investigators. Bilateral versus single internal thoracic artery grafts at 10 years.N Engl J Med. 2019; 380: 437-446Crossref PubMed Scopus (206) Google Scholar Operations are not drugs, and this impact increases with the complexity of the intervention. We are challenged to participate more enthusiastically in RCTs. I agree that it is incumbent on us to understand the nuances of their design and conduct. I also appreciate their call for statistical methodologists to participate in the construct of guidelines documents. Too often we call for “subject matter experts” to write these documents, which of course only serves to increase the impact of “expert opinion” which, despite our appetite, sits at the bottom of the aforementioned evidence pyramid. Methodologic Considerations on Four Cardiovascular Interventions Trials With Contradictory ResultsThe Annals of Thoracic SurgeryVol. 111Issue 2PreviewContradictory findings from randomized trials addressing similar research questions are not uncommon in medicine. Although differing results may reflect true differences in the treatment effects or in the deliverability of the intervention, more commonly it is as a consequence of small but important discrepancies in study design. Full-Text PDF

Bilateral internal thoracic artery grafting in patients with left main disease: a single-center experience.

We compared early and long-term outcomes between bilateral internal thoracic artery (BITA) grafting and single internal thoracic artery (SITA) grafting in patients with LM disease. We evaluated the outcomes of all patients with LM disease who underwent revascularization in our center during 1996-2011. Variables that were adjusted for in a multivariate analysis and in propensity matching included age, sex, comorbid diseases, repeat operation, the number of diseased vessels, other conduits used, the use of sequential grafting, the number of grafts constructed, and the operative era (1996-2000 vs. 2001-2011). In total, 949 patients with LM disease underwent BITA grafting and 564 underwent SITA grafting during the study period. SITA patients were more often female and more likely to have comorbidities such as chronic obstructive pulmonary disease, ejection fraction <30%, recent myocardial infarction, diabetes, congestive heart failure, chronic renal failure, and peripheral vascular disease, and to have undergone an emergency operation. We found no statistically significant difference between the SITA and BITA groups in 30-day mortality (4.8% vs. 3.3%, P = 0.136), sternal wound infection (2.0% vs. 2.4%, P = 0.548), and stroke (3.2% vs. 4.4%, P = 0.234). BITA patients had improved long-term survival (70.1% vs. 52.0% p<0.001), median follow-up of 15 years. In multivariate analysis, after propensity score matching (477 matched pairs), this finding was not statistically significant (P = 0.135). This study did not demonstrate a clear benefit of BITA grafts among patients with LM disease.