Up-to-Date, Skeletonized or Pedicle Bilateral Internal Mammary Artery; Does It Matter?

PURPOSE: In this article, we reported on the up-to-date literature regarding skeletonized bilateral internal mammary artery (BIMA) flow and the effect on sternal perfusion. We also reviewed the pros and cons of the skeletonization technique versus the conventional pedicle technique for harvesting the BIMA. METHODS: We performed an up-to-date review using the PubMed database, with a specific focus on the contemporary published literature. RESULTS: BIMA skeletonization can preserve the sternal microcirculation, minimize tissue damage, and maintain blood supply to the chest wall at the tissue level. This effect is also apparent in diabetics. Deep sternal wound infection (DSWI) rates are significantly less with skeletonization versus the conventional pedicle technique and are comparable to single internal mammary artery harvesting. CONCLUSIONS: Contemporary large-scale studies demonstrate that skeletonization of the BIMA increases conduit length, provides superior flow, reduces the incidence of DSWIs, and improves late survival. Hopefully, this review will increase awareness of the compelling evidence in favor of using skeletonized internal mammary arteries and stimulate increased uptake of BIMA revascularization surgery.

Long-term outcomes of percutaneous revascularization for internal mammary artery-left anterior descending artery bypass failure.

Despite the excellent long-term results of internal mammary artery (IMA)-left anterior descending (LAD) bypass, percutaneous revascularization of IMA is sometimes required for IMA-LAD bypass failure. However, its clinical outcomes have not been fully elucidated. The aim of this study was to investigate the long-term clinical outcomes, including target lesion revascularization (TLR) following contemporary percutaneous revascularization of failed IMA bypass graft. We examined data of 59 patients who had undergone percutaneous revascularization of IMA due to IMA-LAD bypass failure at nine hospitals. Patients with IMA graft used for Y-composite graft or sequential bypass graft were excluded. The incidence of TLR was primarily examined, whereas other clinical outcomes including cardiac death, myocardial infarction, and target vessel revascularization were also evaluated. Mean age of the enrolled patients was 67.4 ± 11.3 years, and 74.6% were men. Forty patients (67.8%) had anastomotic lesions, and 17 (28.8%) underwent revascularization within three months after bypass surgery. Procedural success was achieved in 55 (93.2%) patients. Stent implantation was performed in 13 patients (22.0%). During a median follow-up of 1401 days (interquartile range, 282-2521 days), TLR was required in six patients (8.5% at 1, 3, and 5 years). Patients who underwent percutaneous revascularization within 3 months after surgery tended to have a higher incidence of TLR. Clinical outcomes of IMA revascularization for IMA-LAD bypass failure were acceptable.

Risks and Outcomes of Reoperative Cardiac Surgery in Patients With Patent Bilateral Internal Thoracic Artery Grafts.

BACKGROUND: Reoperative cardiac surgery in patients with patent bilateral internal thoracic artery (ITA) grafts is technically challenging. METHODS: From 2008 to 2017, of 7640 patients undergoing reoperative cardiac surgery, 116 (1.5%) had patent bilateral ITA grafts, including 28 with a right ITA crossing the midline. Mean age was 70 ± 9.6 years, and 111 patients (96%) were men. Reoperations included isolated coronary artery bypass grafting (n = 11), isolated valve (n = 55), valve + coronary artery bypass grafting (n = 26), and other procedures (n = 24). Clinical details, intraoperative management, and perioperative outcomes were analyzed. RESULTS: Aortic cannulation was central in 64 patients (56%) and through the femoral or axillary artery in 50 (44%). Four patients (3.4%) had planned transection and reattachment of ITAs crossing the midline, and 4 (3.4%) had ITA injuries, all right ITAs, 3 crossing the midline; 3 were repaired with an interposition vein graft, and 1 was managed by translocating the right ITA as a Y-graft off another graft. Patent ITAs were managed by atraumatic occlusion during aortic clamping in 90 patients (78%) and by systemic cooling without ITA occlusion in 19. There were 6 operative deaths, all due to low cardiac output syndrome (5.2%); 4 strokes (3.4%); and 5 cases of new postoperative dialysis (4.3%). CONCLUSIONS: Risk of injury to bilateral ITA grafts during reoperation is high, and right ITAs crossing the midline present a particular risk of injury and should inform planning for primary coronary artery bypass grafting. Risk of low cardiac output syndrome underscores the challenge of ensuring adequate myocardial protection.

A New Current to The Armamentarium: Is the CHA2DS2-Vasc-HS Score Predictive of Low Left Internal Mammary Artery (LIMA) Flow in Patients Underwent Coronary Bypass Surgery?

INTRODUCTION: Left internal mammary artery (LIMA) grafts should be used in patients undergoing CABG. No other procedure results in patency equivalent to that of the left anterior descending coronary artery (LAD)-LIMA bypass graft. The CHA2DS2-Vasc-HS scoring system can be used to successfully predict CAD severity in stable CAD patients. We aimed to investigate the relationship between LIMA flow and the CHA2DS2-Vasc-HS score. METHODS: A total of 684 patients, who underwent CABG surgery, were included in this study. Previous history of bypass surgery, emergency operations, patients with Leriche syndrome and patients with severe obstructive pulmonary and subclavian artery disease were excluded from our study. Patients with a LIMA flow that was suitable for bypass grafting, as determined during the intraoperative evaluation, were included in the low LIMA flow group, and the CHA2DS2-Vasc-HS score was calculated for all patients. RESULTS: Patients in the low LIMA flow group (Group 1) were older. The CHA2DS2-Vasc-HS score (P < 0.001), presence of mild or moderate COPD (P = 0.022), number of severely diseased vessels (P = 0.036), and BMI (P < 0.001) were independent predictors of poor LIMA flow. The cutoff value of the CHA2DS2-VASc-HS score for the prediction of poor LIMA flow was >5.5, with a sensitivity of 92.9% and specificity of 83.4% (AUC: 0.938, 95% Cl: 0.906 - 0.970, P < 0.001). CONCLUSION: A preoperative high CHA2DS2-Vasc-HS score can be used to predict low intraoperative LIMA flow. The CHA2DS2-Vasc-HS score is an easy-to-use and reliable estimation method and can be used as an additional preoperative of LIMA flow in patients undergoing CABG due to severe CAD.

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

Background We compared early outcomes, at a single academic institution, of implementing full coronary revascularization in coronary artery bypass grafting using multiarterial Y-composite grafts with multiple sequential anastomoses. Methods and Results Clinical records of 425 consecutive patients who underwent coronary artery bypass grafting using Y-grafting with left internal mammary artery and radial artery (Y-RA group) or right internal mammary artery (Y-RIMA group) from 2015 to 2019, were reviewed. These were compared with the institutional experience of isolated coronary artery bypass grafting cases (in situ on pump/off pump) for the same period of time. When comparing the 4 groups, the Y-RIMA/RA groups revealed a higher number of distal anastomosis than the in situ on- or off-pump groups. When the number of distal arterial anastomosis was analyzed, there was a superiority of using the Y-configuration compared with the in situ approach. Moreover, there were no significant differences among groups for mortality and/or major adverse cardiac and cerebrovascular events in hospital or at 30-day follow-up. A subanalysis comparing the Y-RIMA group with the Y-RA group showed that complementary grafts to the Y-construct were required to accomplish full revascularization more frequently in the Y-RIMA group. Full-arterial revascularization was achieved in 92.2% of the Y-RA group and 72.0% of the Y-RIMA group (P<0.001). In 82.8% of the Y-RA group and 30.8% of the Y-RIMA group, revascularization was completed as an anaortic procedure (P<0.001). Conclusions The 2 types of arterial Y-composite grafting were able to be introduced in the routine practice of our institution showing comparable results to the established institutional practice. This procedure allowed for more arterial distal anastomosis to be performed safely without compromising outcomes.

Myocardial Bridge Bypass Graft: A Novel Surgical Procedure for Extensive Myocardial Bridges.

In patients with myocardial bridges (MBs) and insufficient medical management, the optimal surgical strategy remains undetermined. Based on computer simulations we developed a novel procedure, MB bypass grafting, that showed better hemodynamics compared with coronary artery bypass grafting in a simulation study. In this novel procedure the left internal mammary artery was used to connect the proximal and distal ends of the MB. For the first time we used MB bypass grafting to treat a patient with extensive MB. The patient recovered well after surgery, and the left internal mammary artery graft remained patent 3 months postoperatively.

Association of Age With 10-Year Outcomes After Coronary Surgery in the Arterial Revascularization Trial.

BACKGROUND: The association of age with the outcomes of bilateral internal thoracic arteries (BITAs) versus single internal thoracic arteries (SITAs) for coronary bypass grafting (CABG) remains to be determined. OBJECTIVES: The purpose of this study was to evaluate the association between age and BITA versus SITA outcomes in the Arterial Revascularization Trial. METHODS: The primary endpoints were all-cause mortality and a composite of major adverse events, including all-cause mortality, myocardial infarction, or stroke. Secondary endpoints were bleeding complications and sternal wound complications up to 6 months after surgery. Multivariable fractional polynomials analysis and log-rank tests were used. RESULTS: Age did not affect any of the explored outcomes in the overall BITA versus SITA comparison in the intention-to-treat analysis and in the analysis based on the number of arterial grafts received. However, when the intention-to-treat analysis was restricted to the populations of patients between age 50 and 70 years, younger patients in the BITA arm had a significantly lower incidence of major adverse events (p = 0.03). CONCLUSIONS: Our results suggest that BITA may improve long-term outcome in younger patients, although more randomized data are needed to confirm this hypothesis.

The Growth Potential and Patency of Free Right Internal Thoracic Arteries Verified by Computed Tomography Angiography.

BACKGROUND: The use of the left internal thoracic artery (LITA) is the gold standard in coronary artery bypass graft surgery (CABG). Multiarterial grafting for CABG is being increasingly emphasized. This study aimed to resolve the utility of the right internal thoracic artery (RITA) for multiple CABG as "free" RITA and described new evidence. METHODS: One hundred sixty-three patients received solo CABG with bilateral internal thoracic arteries between 2005 and 2018. The RITA was used as in situ RITA, group A (n = 62), and the composite graft created with saphenous vein graft (SVG), group B (n = 101). The patency rate and graft size of the composite free RITA and SVG were examined by coronary computed tomography angiography. RESULTS: The average number of distal anastomoses per patient was 3.4 ± 1.0 in group A, and 4.2 ± 1.1 in group B (P < .001). The sequential grafting with free RITA was in 86 patients. The patency rate of both LITA and RITA was similar in both groups. In group B, 40 patients received late computed tomography angiography at a mean of 46 months (range, 17 to 175). The late patency rate was 95.1% in LITA and 96.9% in free RITA. The diameter of free RITA increased from 2.06 ± 0.34 mm to 2.37 ± 0.23 mm (P = .036); that of in situ LITA increased from 2.08 ± 0.51 mm to 2.44 ± 0.49 mm (P = .047); and that of composite SVG decreased from 4.1 ± 0.9 mm to 2.6 ± 0.7 mm (P < .001). CONCLUSIONS: Multiple bypass grafting can be sufficiently achieved with LITA and free RITA. The growth potential of free RITA and in situ LITA might play the important role of expected long-term patency.

Application of bilateral internal mammary artery with different configurations in coronary artery bypass grafting.

BACKGROUND: A large number of studies have shown that BIMA grafting is superior to single internal mammary artery grafting in cardiac function protection and long-term survival after surgery. While, there is still no consensus on how is the best configuration to use BIMA. This study aims to compare intraoperative blood flow, early clinical results and early postoperative patency of different configurations of BIMA. METHODS: There were 74 patients who underwent CABGs with bilateral internal mammary artery with different configurations we included. According to the different target territories that RIMA grafted to, the patients were divided into bilateral group (group I) with 20 cases and left group (group II) with 54 cases. Intraoperative blood flow, early clinical results and early postoperative patency of different configurations of BIMA were compared. RESULTS: There was no difference in the early postoperative death and major complications between group I and Group II(P>0.05). Compared with the LIMA in group II, the LIMA in group I had a slightly higher DF value (76.7 ± 6.2 vs 73.1 ± 6.8, P = 0.040). Compared with the RIMA in group II, the RIMA in group I had a slightly higher MGF (51.7 ± 34.4 ml/min vs 31.4 ± 21.4 ml/min, P = 0.024). There was no difference in the other TTFM parameters of LIMA and RIMA between group I and Group II(P>0.05). Further subgroup analysis revealed that compared with free RIMA in group II, in situ RIMA had a higher DF value (71.4 ± 7.8 vs 61.8 ± 18.1,P = 0.025). The PI of LIMA in free RIMA subgroup was higher than the PI of LIMA in in-situ RIMA subgroup (3.0 ± 1.6 vs 2.1 ± 1.0,P = 0.018). The results of early postoperative CTA examination showed that all IMAs grafts were completely patent. CONCLUSIONS: The use of BIMA for CABG is safe and efficacious, RIMA used in right coronary artery received more satisfactory graft flow. BIMA with no stenosis and occlusion in the early stage, therefore is the ideal and stable coronary bypass graft.

Radial Artery vs Bilateral Mammary Composite Y Coronary Artery Grafting: 15-Year Outcomes.

BACKGROUND: Total arterial coronary revascularization for three coronary territory disease can be achieved with a second arterial conduit joined to the left internal mammary artery as a Y graft, by using either a radial artery (RAY) or a second mammary artery (BIMAY). METHODS: Patients undergoing total arterial revascularization for three coronary territory disease were identified from two cardiac surgical databases (in Sydney and Melbourne, Australia) using Society of Thoracic Surgeons-based definitions. BIMAY-treated patients underwent surgery between 1994 and 2009, mostly using an age-limited protocol, whereas RAY-treated patients underwent surgery between 1996 and 2003 without age limits. All-cause mortality data were acquired from the national death registry, and survival was estimated by the Kaplan-Meier method. Propensity score matching was performed using 13 variables. Given the age imbalance between the groups, the primary comparison was performed for age 66 years or younger. RESULTS: Overall, 1896 patients underwent RAY procedures, and 720 patients underwent BIMAY operations. Older age at surgery was the strongest independent predictor of mortality, with a hazard ratio of 2.06, and a 95% confidence interval of 1.93, 2.22 (P < .001). After propensity score matching, we identified 299 pairs of patients 66 years of age or younger with no preoperative or operative differences and similar ages at surgery: RAY 56.4 ± 7.0 years of age vs BIMAY 56.4 ± 6.8 years of age (P = .96). The RAY group had 4.0 ± 0.9 grafts, and the BIMAY group had 3.9 ± 0.9 grafts (P = .814). All-cause mortality was not different, with the proportion surviving at 15 years at 74.9% for the RAY group vs 76.2% for the BIMAY group (P = .211). CONCLUSIONS: Survival was not different between the RAY and BIMAY groups for total arterial revascularization of three coronary territory bypass grafting.

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

BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

Bilateral vs Single Internal Mammary Artery Grafts for Coronary Artery Bypass in the United States.

BACKGROUND: The use of the bilateral internal mammary artery (BIMA) in coronary artery bypass grafting remains controversial. The objective of this study was to investigate the long-term outcomes using the BIMA vs the single internal mammary artery (SIMA) in the United States. METHODS: Medicare beneficiaries who underwent primary isolated coronary artery bypass surgery using the SIMA or BIMA from 1999 to 2010 were included in this retrospective study, with follow-up through 2014. Greedy matching algorithms were used for 1:4 matching on propensity score based on age, gender, year of surgery, and comorbidities. Kaplan-Meier survival analyses were performed. The primary outcome was death from any cause. RESULTS: A total of 1,156,339 and 25,005 patients who were 72 ± 7.6 years of age and 70.3 ± 7.9 years of age underwent primary isolated coronary artery bypass surgery using SIMA and BIMA, respectively. Matching created comparable groups with 95,780 SIMA and 24,160 BIMA patients. Matched median survival using SIMA vs BIMA was 11.8 vs 12.4 years (P < .001) and 9.6 vs 10 years in diabetic patients (P = .006), respectively. At 10 years of follow-up, the respective survival rates of using SIMA vs BIMA were 58.3% vs 61.1%, respectively. The stratified matched median survival using SIMA vs BIMA with 1, 2, 3, and 4 or more aortocoronary bypasses were 11.8 vs 12.3 years (P = .005), 11.7 vs 12.5 years (P < .001), 11.9 vs 12.3 years (P = .01), and 11.4 vs 12 years (P = .02), respectively. CONCLUSIONS: Primary isolated coronary artery bypass surgery using the BIMA rather than the SIMA was associated with improved long-term survival. This survival advantage was independent of aortocoronary bypass grafts or patient diabetes status.

Computational fluid dynamics of internal mammary artery-left anterior descending artery anastomoses.

OBJECTIVES: The aim of this study was to elucidate the remodelling of the internal mammary artery (IMA)-left anterior descending artery anastomosis and compare 2 different anastomosis techniques (end-to-side versus side-to-side) using computational fluid dynamics. METHODS: This study included 9 patients. Computed tomography (CT) angiography was performed immediately after coronary artery bypass grafting (CABG) and at 3-6 months later. The computational fluid dynamics models were made using the CT data. The pulsatile 3-dimensional blood flow was achieved with the finite volume method to evaluate the postoperative morphological and haemodynamic changes at the anastomosis in each patient. Flow velocity distribution, wall shear stress (WSS) and its fluctuation oscillatory shear index were measured. RESULTS: No early or mid-term graft occlusion was observed in the study series. In the side-to-side anastomosis, pouch formation at the distal end of IMA caused a vortex flow with low WSS immediately after CABG. However, at 3-6 months after surgery, this pouch disappeared. As a result, the laminar straight flow with uniform WSS distribution was achieved inside the anastomosis. In the end-to-side anastomosis, the anastomosis shape was remodelled, resulting in a laminar flow pattern with uniform WSS distribution. A patchy high oscillatory shear index was detected at the IMA wall on the top of anastomosis in either anastomosis techniques immediately after the surgery, but it disappeared at 3-6 months after surgery. CONCLUSIONS: Regardless of the anastomosis technique used, a successful remodelling of the IMA-left anterior descending artery anastomosis shape was achieved a few months after surgery, resulting in a straightforward flow streamline, with uniform WSS distribution and minimal oscillatory shear index.

MIDCAB Tips and tricks for a successful procedure.

Minimally invasive direct coronary artery bypass (MIDCAB) for a left internal mammary artery on left anterior descending (LIMA-LAD) graft, is a safe and relatively less traumatic surgical technique. Adoption in some centers has been slow because of perceived technical difficulty, but it should be considered a first-choice therapy for patients with isolated proximal LAD lesions or multi-vessel disease, and as a component of a hybrid revascularization strategy.  Results in our institute, where we have been using MIDCAB for more than 20 years, confirm both its short- and long-term efficacy. This video tutorial demonstrates the technical aspects of the procedure.

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

OBJECTIVE: 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. METHODS: 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). RESULTS: 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). CONCLUSION: This study did not demonstrate a clear benefit of BITA grafts among patients with LM disease.

Uncommon Anatomic Variation of Left Internal Mammary Artery: God-Created Y-Graft Conduit.

The left internal mammary artery is the most accepted and widely used conduit in coronary artery bypass grafting. This report presents a rare case of very early bifurcation of the left internal mammary artery at the level of the third intercostal space.

Bilateral Internal Thoracic Artery In Situ Versus Y-Composite Graftings: Long-term Outcomes.

BACKGROUND: We compared 10-year graft patency rates and long-term clinical outcomes after off-pump coronary artery bypass grafting using bilateral internal thoracic arteries (ITAs) as in situ grafts with those using bilateral ITAs as Y-composite grafts. METHODS: Of 509 patients who underwent off-pump coronary artery bypass grafting using bilateral ITAs, bilateral ITAs were used as in situ grafts in 172 patients (group I) and as Y-composite grafts in 337 patients (group Y). A propensity score-matched analysis was used to match group I patients (n = 153) with group Y patients (n = 153). Ten-year angiographic patency rates and long-term clinical outcomes were compared. The follow-up data were complete in 99.2% of patients (505/509) with a median follow-up duration of 175 months. RESULTS: Ten-year overall patency rates and patency rates for distal anastomoses using bilateral ITAs were 87.5% (356/407) and 89.2% (297/333), respectively, in the propensity score-matched groups. No differences in overall patency rates (groups I vs Y, 84.9% vs 89.5%, P = .277) and bilateral ITA patency rates (groups I vs Y, 86.5% vs 91.1%, P = .282) were found between the propensity score-matched groups. There were no differences in the overall survival and cumulative incidence of cardiac death between the propensity score-matched groups (P = .312 and P = .812, respectively) up to 15 years after surgery. Cumulative incidences of target vessel revascularization (P = .606), reintervention (P = .849), and major adverse cardiac events (P = .672) were also similar between the propensity score-matched groups up to 15 years after surgery. CONCLUSIONS: Off-pump coronary artery bypass grafting using bilateral ITAs as in situ versus Y-composite grafts demonstrated no differences in terms of 10-year patency rates and long-term clinical outcomes between the groups.