Internal Mammary Artery Conduit Research Articles

Anomalous right coronary artery managed with bypass and proximal ligation

BackgroundAn anomalous origin and inter-arterial course of the right coronary artery is a rare anomaly that can lead to sudden ischemic cardiac death if left untreated. We present a case of a patient with an anomalous right coronary artery originating from the left coronary sinus and an inter-arterial course that was managed with coronary artery bypass surgery using a suitable internal mammary artery conduit. The proximal right coronary artery was ligated to prevent competitive flow.Case PresentationA 69 year-old-male with a ten-year history of intermittent chest pain and dyspnea with a negative workup underwent a cardiac catheterization, which showed an anomalous right coronary artery (RCA) originating from the left coronary sinus, with an inter-arterial course between the ascending aorta and pulmonary artery, and approximately 70% narrowing of the proximal RCA. The patient underwent an on-pump coronary artery bypass using the right internal mammary artery (RIMA) as a conduit, with segment 2 of the RCA being the target. The proximal RCA was ligated. Intra-operatively, there were no signs of ischemia or arrhythmia. The patient was successfully taken off cardiopulmonary bypass and eventually discharged home.ConclusionSymptomatic anomalous origin of the right coronary artery with an inter-arterial course can be treated successfully with coronary artery bypass surgery with the internal mammary artery as a conduit. Ligation of the proximal right coronary artery is essential to minimize competitive flow through the bypass graft.

Male-female differences following concomitant coronary artery bypass grafting and aortic valve replacement surgery.

Combined coronary artery bypass grafting (CABG) and aortic valve replacement (AVR), and female sex are associated with increased perioperative mortality in clinical risk scores. This study investigated male-female differences in short-term outcome stratified by age groups. All patients undergoing AVR and CABG between January 2001 and June 2021 at our institution were included. 1963 patients were grouped by decades into: 59years and younger (n=127), 60-69 (n=471), 70-79 (n=1070), and 80years and older (n=295). The primary end points of this study were 30 and 180days mortality. Secondary end points were influence of preoperative risk factors and impact of sex on survival and postoperative major adverse events. Female patients showed higher 30 and 180days mortality after combined CABG and AVR surgery (8.3% vs. 4.2%, P<0.01; 15.8% vs. 9.4%, P<0.01). Stratified by age groups, 30 and 180days mortality remained significantly higher in septuagenarians (9.6% vs. 2.5%, P<0.01; 16.3% vs. 7.7%, P<0.01). Females were significantly older, had better preserved left ventricular function, and higher incidence of diabetes mellitus compared with male patients in this subgroup (P<0.01; P=0.01; P<0.01). Additionally, females received significantly less internal mammary artery (IMA) conduits (P<0.01). Female sex (OR: 3.33, 95% CI: [1.76-6.31]; 1.93, [1.22-3.06]), higher age (1.28, [1.13-1.45]; 1.16, [1.06-1.26]), diabetes mellitus (1.93, [1.03-3.60]; 1.70, [1.08-2.67]) and LVEF <30% (3.26, [1.48-7.17]; 2.23, [1.24-4.02]) were correlated with 30 and 180days mortality, respectively. Upon multivariable testing, sex (1.77, [1.21-2.58]) and LVEF <30% (3.71, [2.39-5.76]) remained independent predictors for major adverse postoperative events. Infrequent use of IMA grafts was associated with increased 30 and 180days mortality as well as adverse events (0.47, [0.25-0.87]; 0.46, [0.29-0.72]; 0.61, [0.42-0.88]). Sex disparities in baseline characteristics may delay operative intervention in female patients. The inherent risk profiles might be responsible for outcome differences in septuagenarians.

Coronary Artery Bypass Surgery: Evidence-Based Practice.

Coronary artery bypass graft (CABG) surgery remains a pivotal cornerstone, offering established symptomatic alleviation and prognostic advantages for patients grappling with complex multivessel and left main coronary artery diseases. Despite the lucid guidance laid out by contemporary guidelines regarding the choice between CABG and percutaneous coronary intervention (PCI), a notable hesitation persists among certain patients, characterized by psychological reservations, knowledge gaps, or individual beliefs that sway their inclination toward surgical intervention. This comprehensive review critically synthesizes the prevailing guidelines, modern practices, and outcomes pertaining to CABG surgery, delving into an array of techniques and advancements poised to enhance both short-term and enduring surgical outcomes. The exploration encompasses advances in on-pump and off-pump procedures, conduit selection strategies encompassing the bilateral utilization of internal mammary artery and radial artery conduits, meticulous graft evaluation methodologies, and the panorama of minimally invasive approaches, including those assisted by robotic technology. Furthermore, the review navigates the terrain of hybrid coronary revascularization, shedding light on the pivotal roles of shared decision-making and the heart team in shaping treatment pathways. As a comprehensive compendium, this review not only navigates the intricate landscape of CABG surgery but also aligns it with contemporary practices, envisioning its trajectory within the evolving currents of healthcare dynamics.

Outcomes of Coronary Artery Bypass Grafting With Bilateral Internal Mammary Artery in Obese Patients

BackgroundThe purpose of this study was to evaluate postoperative outcomes with the use of bilateral internal mammary artery (BIMA) conduits in obese patients. MethodsBetween January 2003 and December 2018, 8109 patients underwent isolated coronary artery bypass grafting, including 7218 (89%) treated with single internal mammary artery (SIMA) and 891 (11%) treated with BIMA grafts. Patients were divided into 3 groups according to preoperative body mass index (BMI): normal, BMI <25 kg/m2 (22.2%); overweight, BMI of 25 to <30 kg/m2 (37.2%); and obese, BMI ≥30 kg/m2 (40.6%). In each group, BIMA and SIMA patients were compared to investigate 30-day mortality and postoperative complications. Significant baseline differences were observed between the 3 BMI groups, and such differences were adjusted by inverse probability weighting matching. ResultsThirty-day mortality, deep sternal wound infection (DSWI) rates, and length of hospital stay were 1.4%, 0.5%, and 6.0 ± 9.1 days for the normal group; 0.2%, 1.0%, and 5.5 ± 4.2 days for the overweight group; and 0.9%, 1.8%, and 5.5 ± 4.0 days for the obese group. There was no significant difference in 30-day mortality, incidence of DSWI, and hospital stay between BIMA and SIMA groups, except in the obese group, in which the rate of DSWI was significantly higher in the BIMA patients (3.4% vs 0%; P = .02). ConclusionsBIMA grafts in obese patients can be used without an increase of the 30-day mortality and hospital stay. However, the use of BIMA grafts in obese patients may lead to an increase of postoperative DSWI.

The percutaneous coronary angioplasty gets better, but the surgical coronary artery bypass does not stay behind

Coronary artery bypass grafting remains one of the most frequently performed cardiac operations, with well-established prognostic benefits in patients with multivessel coronary artery disease and left main disease. Despite an increasingly higher patients' risk profile, the results of this procedure have significantly improved over time, with an evident and striking decrease in operative mortality and peri-operative complications. A fair amount of technical and technological refinements has further improved the short- and long-term results of coronary artery bypass surgery. The improvements in the beating heart coronary surgery and aortic 'no-touch' technique, in the appropriate use of conduits (bilateral internal mammary artery, radial artery, and composite conduits configuration), and in the optimization of venous grafts' patency are reviewed.

Abstract 13096: Outcomes After Coronary Artery Bypass Grafting With Bilateral Internal Mammary Arteries in Obese Patients

Introduction: The purpose of this study was to evaluate the postoperative outcomes with the use of bilateral internal mammary artery (BIMA) conduits in obese patients. Methods: Between January 2003 and December 2018, 8109 patients underwent isolated coronary artery bypass grafting (CABG) at our institution, including 7218 (89.0%) treated with single internal mammary artery (SIMA) and 891 (11.0%) treated with BIMA. Patients were divided into three groups according to preoperative body mass index (BMI), normal or BMI&lt;25 (22.2%), overweight or 25-BMI&lt;30 (37.2%), and obese or BMI&gt;30 (40.6%). In each group, BIMA and SIMA patients were compared to investigate the thirty-day mortality and postoperative complications. Significant baseline differences were observed between the three BMI groups and such differences were adjusted via inverse probability weighting matching. Results: The thirty-day mortality, deep sternal wound infection (DSWI) rates and length of hospital stay were 1.4%, 0.5%, and 6.0 ± 9.1 days for the normal group, 0.2%, 1.0% and 5.5 ± 4.2 days for overweight group and 0.9%, 1.8% and 5.5 ± 4.0 days for the obese group. There was no significant difference in the thirty-day mortality, incidence of DSWI and hospital stay between BIMA and SIMA groups, except in the obese group where the rate of DSWI was significantly higher in the BIMA patients (3.4 vs 0.0%, p=0.02). Conclusions: BIMA for isolated CABG in obese patients can be used without an increase of the thirty-day mortality and hospital stay. However, the use of BIMA in obese patients may lead to an increase of postoperative DSWI.

Refractory Angina Secondary to Large Unligated Side Branch of Internal Mammary Artery

Coronary artery disease (CAD) has become a common diagnosis. Managing the symptoms of CAD continues to be an ongoing dilemma requiring optimal medication management or potential revascularization with either percutaneous coronary interventions or coronary artery bypass grafting (CABG). We present a case of debilitating refractory angina in a patient with severe CAD after optimal medical therapy and CABG secondary to coronary steal phenomenon via the left internal mammary artery conduit supplying a large unligated side branch to the internal chest wall. While current data are inconclusive on this phenomenon, our patient had complete resolution of angina following coil embolization of unligated side branch of the internal mammary artery.

OC16 CORONARY ARTERY ENDARTERECTOMY DURING CORONARY ARTERY BYPASS GRAFTING: A SOLUTION FOR COMPLETE REVASCULARIZATION

Abstract Background: Coronary Artery Bypass Grafting (CABG) is one of the most frequently done cardiac surgical procedures. However, with the advancements in catheter-based interventional procedures, the category of patients taken up for CABG is gradually being restricted to more high-risk group. Performance of Off pump coronary artery bypass grafting (OPCAB) with concomitant coronary artery endarterectomy(CE) in patients with severe coronary disease provides more complete revascularization.We examined the technique and early outcomes of OPCAB with coronary endarterectomy (CE). Materials and methods: This is a single institutional retrospective study with 32 patients (26 males, 6 females) underwent concomitant off-pump CE and CABG from 1 october 2016 through 31 october 2017. which was about 11.26 % (32/284) of the OPCAB cases. Average number of coronary bypass grafts were 2.4 ± 0.8. 10 CE procedures were performed with saphenous vein patch. 7 involved left anterior descending artery (LAD) CE with left internal mammary artery (LIMA) conduits. The remaining 3 were diagonal branch artery (D1) CE with saphenous vein bypass conduits. Results: The incidence of postoperative MI was 9%. The 30-day mortality was 3.12% from complications of bowel ischaemia and three patients with septicaemia associated with prolonged intubation. The mean operating time was 138 ± 22 minutes. Conclusion: We have shown that the effect of OPCABG with CE appears to be safe and early outcomes are encouraging. Hence, diffuse disease requiring endarterectomy should not be considered a contraindication to OPCABG. Surgical skills and the suitability criteria of the patients are very important in this regard.

Sequential Grafting of in Situ Skeletonized Left Internal Mammary Artery to the Left Coronary System.

Sequential grafting may be an effective way to maximize the benefits of the left internal mammary artery (LIMA) conduit. Despite increasing clinical application, the strategy of sequential LIMA grafting has not been proven its superiority. This single-center retrospective study aimed to evaluate the in-hospital and mid-term outcomes of sequential grafting of in situ skeletonized LIMA to the left coronary system.According to the use of sequential or separate LIMA grafting, 1505 eligible patients were assigned to a sequential group (n = 230) and a control group (n = 1275). According to sequential LIMA graft configurations, patients with sequential LIMA grafting were divided into a DOM subgroup (n = 113) and a DLAD subgroup (n = 117). The clinical outcomes and LIMA graft patency were investigated and compared.Sequential LIMA grafting compared with separate LIMA grafting was not an independent predictor either of in-hospital adverse events or follow-up survival free from repeat revascularization during the follow-up period of 32.4 ± 8.5 months. Sequential LIMA grafting had similar LIMA graft patency with separate LIMA grafting (99.5% of 1st sequential sites and 97.7% of 2nd sites versus 98.2% of LIMA-LAD grafts) at 32.3 ± 8.5 months after coronary artery bypass grafting (CABG) surgery. Additionally, the two subgroups received similar mid-term clinical outcomes and graft patency of LIMA segments.Sequential grafting of in situ skeletonized LIMA to the left coronary system resulted in excellent clinical outcomes and graft patency. The two sequential LIMA graft configurations received similar clinical outcomes and graft patency.

A comparison of left ventricular function in patients undergoing beating heart bypass surgery using mixed versus pure venous conduits

Background: The pathophysiology of coronary artery disease was established in 1876 by Adam Hammer when he postulated that angina is caused by interruption of coronary blood supply and that myocardial infarction occurred after the occlusion of at least one coronary artery. Aims of the study were to compare the left ventricular function in patients who have undergone beating heart bypass surgery using mixed (internal mammary artery and venous conduits) versus pure Venous conduits, and to compare the incidence of postoperative complications.Methods: It was an observational, analytical study. All patients admitted with triple vessel disease requiring CABG (n=50), with ejection fraction &gt;30%, were subjected to either left internal mammary artery and venous conduits (group A, n=25) or only venous conduits (group B, n=25). Patient who had undergone prior surgical myocardial revascularization, preexisting valvular disease, any evidence of raised pulmonary arterial pressure more than 40/15 mmHg, operated using cardiopulmonary bypass machine, pre-operative use of Intra-Aortic Balloon Pump, any history of neurological dysfunction/Transient ischemic attack, left atrium size more than 5.5 cm were excluded from the studyResults: Improvement in left ventricular function after coronary artery bypass grafting was objectively demonstrated in both the groups. There was a statistically significant increase in mean LVEF in group B (56.16±4.13) compared to group A (51.96±5.30) at 3 months of follow up (p=0.009). The most common complication in both the groups were atrial fibrillation group A=36% (n=9), group= B 16 % (n=4), renal failure group A=12% and group B=8% and sternal wound infection. The post-operative bleeding (Drain output) in first 24 hours was similar in both the groups, 295.56 ml in group A and 265.20ml in group B (p=) with similar hospital stay (group A=9days, group B=8.5days).Conclusions: Patients with venous conduits have better postoperative LVEF as compared to Mixed conduit with similar rate of post-operative complications.

Internal mammary artery conduit re-use in coronary artery bypass grafting: Case series and review

Left internal mammary artery (LIMA) conduit is the gold standard graft for coronary artery bypass. Due to excellent patency rates with this graft it can safely be used in re-operative coronary bypass surgery. The safety of this technique is demonstrated with our report of re-used LIMA conduits in patients with extensive coronary artery disease (CAD). The success of this technique was evaluated by postoperative computerized tomographic angiography which demonstrated patent conduits and flow to the left anterior descending artery (LAD).

A Single Center Experience with Coronary Endarterectomy and Vein Patch Reconstruction

Background: To evaluate the medium and late term outcomes of coronary artery bypass grafting with pull-through coronary endarterectomy using a saphenous vein patch for bypass distal anastomosis site. Methods: Retrospective review of all coronary artery bypass graft (CABG) procedures performed from January 1, 2000 through June 30, 2013 with and without concomitant coronary endarterectomy (CE), was carried out at the Veterans Affairs Medical Center in Washington DC. Patients who underwent concomitant valve operations were excluded. Primary outcome was overall survival, with analyses performed examining CE as well as the use of cardiopulmonary bypass. Secondary outcomes included 30-day mortality and post-operative MI. Results: 1255 CABG operations were performed, 10 of which included CE. All CE procedures were performed with saphenous vein patch. 7 involved left anterior descending artery (LAD) CE with left internal mammary artery (LIMA) conduits. The remaining 3 were diagonal branch artery (D1) CE with saphenous vein bypass conduits. 1-year survival was 70%. 5-year survival was 43% out of 7 patients. Conclusions: Pull-through CE with saphenous vein patch is a safe alternative technique for patients with diffuse coronary artery disease. Perioperative events and intermediate outcomes are favorable, although long-term survival is less than patients without CE.

Intraoperative Administration of Clevidipine to Prevent Vasospasm After Radial and Internal Mammary Artery Grafts During Coronary Artery Bypass Grafting

During coronary artery bypass graft surgery, various arterial and venous conduits have been used to carry blood flow from the aorta to the coronary vasculature. Arterial conduits provide certain advantages over the saphenous vein, including superior long-term patency, relative resistance to the development of atherosclerosis, and greater endothelium-dependent relaxation. However, the perioperative release of catecholamines and thromboxane A, mechanical manipulation, and underlying endothelial cell dysfunction may result in vasoconstriction or vasospasm of the arterial conduit and a compromise of myocardial perfusion. Given these issues, pharmacologic therapy is frequently initiated intraoperatively to prevent vasospasm. Clevidipine is a rapidly acting calcium channel antagonist. Like nicardipine, it is a member of the dihydropyridine subgroup. Its rapid metabolism by tissue and plasma esterases results in an effective half-life of 1 to 3 minutes. We report, for the first time, the perioperative use of clevidipine to prevent vasospasm after coronary artery bypass graft surgery with the use of internal mammary artery and bilateral radial artery conduits. Its potential application in this scenario and advantages when compared with other commonly used agents is discussed.

Recurrence of Coronary-Subclavian Steal Syndrome After Successful Angioplasty of Malfunctioning Arteriovenous Fistula

We report a case of coronary-subclavian steal syndrome, which had been masked by a malfunctioning hemodialysis access vessel and then reappeared after a successful angioplasty of multiple stenoses in the arteriovenous fistula of the left arm in a 61-year-old man. This case suggests that coronary-subclavian steal syndrome should be considered before a coronary artery bypass grafting surgery using internal mammary artery conduit is done, especially when hemodialysis using the left arm vessels is expected.

Relief of Angina Pectoris When Carrying Heavy Loads with the Left Hand in a Patient with Previous Coronary Artery Bypass Graft Operation Who Has Severe Exercise Angina: A Case Report

In patients with known coronary artery disease and/or a history of revascularization, angina pectoris or unstable coronary syndromes are usually attributed to the progression of atherosclerotic lesions rather than an unrecognized great vessel disease. However, for patients with a previous coronary artery bypass graft operation (CABG), during which a left internal mammary artery (LIMA) conduit has been used, great vessel disease, especially subclavian artery stenosis should also be suspected. We present a case of a patient with a LIMA conduit who has angina pectoris on exertion, but interestingly the pain is relieved when he carries heavy loads with his left hand, which can be due to increased blood flow to the LIMA conduit during heavy lifting because of increased peripheral resistance.

Regulation of cell cycle entry by PTEN in smooth muscle cell proliferation of human coronary artery bypass conduits

Proliferation of smooth muscle cells (SMCs) is the key event in the pathogenesis of intimal hyperplasia (IH) leading to coronary artery bypass graft (CABG) occlusion. The saphenous vein (SV) conduits are often affected by IH, while the internal mammary artery (IMA) conduits remain remarkably patent. SMC proliferation is mediated by the cell cycle, under the control of cyclin-dependent kinases (cdks), cdk-inhibitors and the retinoblastoma protein (Rb). Early passage of the SMCs through the cell cycle involves crossing the non-reversible G1 checkpoint, the restriction (R) point. In this study, we investigated the effect of mitogenic insulin-like growth factor (IGF)-1 stimulation on the R-point and its relationship with the phosphorylation of Rb protein and the cdk inhibitors p21 and p27 in SV and IMA SMCs. We observed no change in the R-point following IGF-1 activation in either SV or IMA SMCs. However, Rb-phosphorylation occurred much earlier and was quantitatively greater in SV SMCs than IMA. Overexpression of phosphatase and tensin homologue deleted on chromosome 10 (PTEN) in SV SMCs followed by IGF-1 activation significantly decreased the expression of cyclin E and pRb and induced p27 expression in SV SMCs, while, pRb levels were markedly decreased and p27 levels were significantly increased in IMA SMCs. Silencing the PTEN gene by siRNA transfection of IMA SMCs significantly induced the expression of pRb and inhibited p27 expression, while, the expression levels of cyclin E, pRb, p21 and p27 were unaffected by the silencing of PTEN in SV SMCs. These results demonstrate that the PTEN plays a critical role in regulating cell cycle entry. Therefore, overexpression of PTEN possibly by means of gene therapy could be a viable option in regulating the cell cycle in SV SMCs in the treatment of vein graft disease.

Outcomes after Off-Pump Reoperative Coronary Artery Bypass Grafting

: Application of off-pump techniques to reoperative coronary artery bypass (redo CABG) has been limited by technical difficulty and potential for embolism of atheromatous debris from diseased grafts, resulting in myocardial infarction and rapid hemodynamic deterioration. We compared outcomes after off-pump (OPCAB) and on-pump (ONCAB) in redo CABG. : A retrospective chart review was performed for patients who underwent redo CABG at a single academic institution between January 1997 and December 2004. Outcomes were compared between groups based on intention to treat. Propensity scores were calculated for each patient using 23 preoperative risk factors. Logistic regression was applied for each end point as a function of group and propensity score. : A total of 771 consecutive patients had redo CABG (639 ONCAB and 132 OPCAB); 22 patients (16.7%) were converted from OPCAB to ONCAB for hemodynamic in stability, severe adhesions, or graft injury; 7 patients (1.1%) were converted from ONCAB to OPCAB for severe aortic calcification. Propensity-matched comparison of outcomes after OPCAB versus ONCAB for redo CABG showed that OPCAB was associated with a reduction in postoperative complications, transfusion, atrial fibrillation, and length of stay. OPCAB patients received fewer grafts with similar use of left internal mammary artery conduit; conversion from OPCAB to ONCAB did not reduce the benefit of OPCAB. : OPCAB can be safely and effectively applied to reoperative CABG in selected cases.

Letter by Brilakis and Banerjee Regarding Article, “Impact of Internal Mammary Artery Conduit on Long-Term Outcomes After Percutaneous Intervention of Saphenous Vein Graft”

To the Editor: Mehta and colleagues1 observed 2119 patients with coronary bypass grafts undergoing coronary angiography and then compared (1) patients with and without a patent internal mammary graft and (2) patients who did versus those who did not undergo saphenous vein graft (SVG) percutaneous coronary intervention (PCI). The authors found that patients who underwent PCI of the SVG at the time of angiography had significantly worse clinical outcomes …

Response to Letter Regarding Article, “Impact of Internal Mammary Artery Conduit on Long-Term Outcomes After Percutaneous Intervention of Saphenous Vein Graft”

We thank Drs Brilakis and Banerjee for their insightful comments concerning our recently published study.1 Our goal was to evaluate whether percutaneous interventions of saphenous vein graft (SVG) had any influence on long-term outcomes. In accordance with the retrospective and observational nature of our study, we used currently accepted methodology that included adjustments using a Cox proportional hazard model to account for differences in baseline confounders in the 4 groups. In …

Invited commentary

Gaudino and colleagues [1] have made an interesting and provocative observation that saphenous vein grafts (SVGs) fare poorly in patients undergoing coronary bypass grafting (CABG) after failed intracoronary stents. They hypothesize that patients with in-stent stenosis have an aggressive atherosclerotic disorder that prejudices the fate of both the stent and a subsequent vulnerable vein bypass compared with the internal mammary artery (IMA) or other arterial conduit.