Left Internal Mammary Artery Versus Coronary Stents: Impact on Downstream Coronary Stenoses and Conduit Patency

Impacts of the SYNTAX score I, II and SYNTAX score II 2020 on left main revascularization

Patients with left main coronary artery disease (LMCAD) with a high SYNTAX score (SS) were excluded from randomized studies that comparing percutaneous coronary intervention (PCI) and coronary artery bypass grafting (CABG). We sought to compare PCI and CABG in the real-world practice and investigate the impact of SS I, SS II, and SS II 2020 on clinical outcomes. In total, 292 Patients with LMCAD (173 PCI, 119 CABG) treated between 2017 and 2021 were enrolled. The primary outcome was major adverse cardiovascular events (MACE), a composite of all-cause death, stroke, or myocardial infarction (MI). The mean SS I was high in both groups (PCI vs. CABG: 31.64 ± 11.45 vs. 32.62 ± 11.75, p = 0.660). The primary outcome occurred in 28 patients (16.2%) in the PCI group and in 19 patients (16.0%) in the CABG group without significant difference [adjusted hazard ratio, 95% CI = 0.98 (0.51-1.90), p = 0.97] over the follow-up period (26.9 ± 17.7 months). No significant difference was observed in all-cause mortality (11.6% vs. 11.8%, p = 0.93) or stroke rates (3.5% vs. 5.0%, p = 0.51) between groups. However, PCI was associated with higher MI (4.6% vs. 0.8%, p < 0.05) and revascularization rates (26% vs. 5.9%, p < 0.001). Prognostic value of the SS I, SS II and SS II 2020 on the primary outcome was not relevant in the PCI group. Among patients with LMCAD, PCI and CABG did not significantly differ in the composite endpoint of all-cause death, stroke, and MI. These results support the potential expansion of PCI indications in LMCAD management for whom are ineligible for CABG with complex coronary artery disease.

Twenty-year outcomes of minimally invasive direct coronary artery bypass surgery: The Leipzig experience

OBJECTIVE

Minimally invasive direct coronary artery bypass (MIDCAB) surgery involving left anterior descending coronary artery grafting with the left internal thoracic artery through a left anterior small thoracotomy is being routinely performed in some specified centers for patients with isolated complex left anterior descending coronary artery disease, but very few reports regarding long-term outcomes exist in literature. Our study was aimed at assessing and analyzing the early and long-term outcomes of a large cohort of patients who underwent MIDCAB procedures and identifying the effects of changing trends in patient characteristics on early mortality.

METHODS

A total of 2667 patients, who underwent MIDCAB procedures between 1996 and 2018, were divided into 3 groups on the basis of the year of surgery: group A, 1996-2003 (n = 1333); group B, 2004-2010 (n = 627) and group C, 2011-2018 (n = 707). Groupwise characteristics and early postoperative outcomes were compared. Long-term survival for all patients was analyzed and predictors for late mortality were identified using Cox proportional hazards methods.

RESULTS

The mean age was 64.5 ± 10.9 years and 691 (25.9%) patients were female. Group C patients (log EuroSCORE I = 4.9 ± 6.9) were older with more cardiac risk factors and comorbidities than groups A (log EuroSCORE I = 3.1 ± 4.5) and B (log EuroSCORE I = 3.5 ± 4.7). Overall and groupwise in-hospital mortality was 0.9%, 1.0%, 0.6%, and 1.0% (P = .7), respectively. Overall 10-, 15-, and 20-year survival estimates for all patients were 77.7 ± 0.9%, 66.1 ± 1.2%, and 55.6 ± 1.6%, respectively.

CONCLUSIONS

MIDCAB can be safely performed with very good early and long-term outcomes. In-hospital mortality remained constant over the 22-year period of the study despite worsening demographic profile of patients.

Investigation of the effects of diabetes mellitus on left internal thoracic artery flow patterns in patients scheduled to undergo coronary bypass graft surgery

PURPOSE

Diabetes mellitus (DM) plays a key role in the formation and prognosis of cardiovascular diseases. In this study, we aimed to investigate the effects of DM and glycemic control on left internal thoracic artery (LITA) Doppler flow in patients scheduled to undergo coronary artery bypass graft (CABG) surgery.

METHODS

Patients who were hospitalized with a planned isolated CABG operation to our clinic between October 1, 2019 and March 1, 2020 were consecutively included in this prospective study. The patients were divided into three groups as those without DM (Group 1), those with DM and HbA1c values of below 7.5 (Group 2), and those with DM and HbA1c values of 7.5 and above (Group 3). The differences between the LITA Doppler flow patterns of the patients were analyzed.

RESULTS

The mean ages of Group 1 (n = 103), Group 2 (n = 42), and Group 3 (n = 47) were 59.8 ± 9.6 years, 60.5 ± 9.3 years, and 61.9 ± 8.1 years, respectively. The groups differed in terms of diameter, volume, Vmax, pulsality index (PI), and resistive index (RI) values, both when the groups were compared among themselves (P < .001, for all), and when they were compared between those with (Groups 2 and 3) and without DM (Group 1) (P < .001, for all). Volume (R = -0.627, P < .001) and Vmax (R = -.450, P < .001) were moderately negatively correlated, while PI (R = .523, P < .001) and RI (R = 0.598, P < 0.001) were moderately positively correlated with HbA1c levels.

CONCLUSION

In this study, we showed that increased HbA1c levels may be associated with significant functional and structural changes of LITA.

IACTS position statement on "2021 ACC/AHA/SCAI Guideline for Coronary Artery Revascularization": section 7.1-a consensus document

American College of Cardiology (ACC), American Heart Association (AHA) and Society for Cardiovascular Angiography and Interventions (SCAI) recently released the Clinical Practice Guidelines for myocardial revascularization [1]. The guidelines were the felt need of the fraternity and this single all-encompassing document, relegating the previous six guidelines on the subject to archives, is indeed welcome. However, the downgrading of coronary artery bypass surgery for stable multivessel coronary artery disease and its bracketing with percutaneous coronary interventions has caused a lot of anguish in the surgical fraternity. This document presents the official viewpoint of the Indian Association of Cardiovascular and Thoracic Surgeons on the matter.

Resilience of the Internal Mammary Artery to Atherogenesis: Shifting From Risk to Resistance to Address Unmet Needs

Fueled by the global surge in aging, atherosclerotic cardiovascular disease reached pandemic dimensions putting affected individuals at enhanced risk of myocardial infarction, stroke, and premature death. Atherosclerosis is a systemic disease driven by a wide spectrum of factors, including cholesterol, pressure, and disturbed flow. Although all arterial beds encounter a similar atherogenic milieu, the development of atheromatous lesions occurs discontinuously across the vascular system. Indeed, the internal mammary artery possesses unique biological properties that confer protection to intimal growth and atherosclerotic plaque formation, thus making it a conduit of choice for coronary artery bypass grafting. Its endothelium abundantly expresses nitric oxide synthase and shows accentuated nitric oxide release, while its vascular smooth muscle cells exhibit reduced tissue factor expression, high tPA (tissue-type plasminogen activator) production and blunted migration and proliferation, which may collectively mitigate intimal thickening and ultimately the evolution of atheromatous plaques. We aim here to provide insights into the anatomy, physiology, cellular, and molecular aspects of the internal mammary artery thereby elucidating its remarkable resistance to atherogenesis. We propose a change in perspective from risk to resilience to decipher mechanisms of atheroresistance and eventually identification of novel therapeutic targets presently not addressed by currently available remedies.

Prognostic Effect of the SYNTAX Score on 10-Year Outcomes After Left Main Coronary Artery Revascularization in a Randomized Population: Insights From the Extended PRECOMBAT Trial

Background

The long‐term prognostic effect of the SYNTAX (Synergy Between Percutaneous Coronary Intervention With Taxus and Cardiac Surgery) score (SS) after percutaneous coronary intervention (PCI) or coronary artery bypass graft (CABG) for left main coronary artery disease is controversial.

Methods and Results

In the PRECOMBAT (Premier of Randomized Comparison of Bypass Surgery Versus Angioplasty Using Sirolimus‐Eluting Stent in Patients With Left Main Coronary Artery Disease) trial, 600 patients with left main coronary artery disease were randomized to undergo PCI with drug‐eluting stents (n=300) or CABG (n=300). We compared 10‐year outcomes after PCI and CABG according to SS categories and evaluated the predictive value of SS in each revascularization arm. The primary outcome was a major adverse cardiac or cerebrovascular event (composite of death, myocardial infarction, stroke, or ischemia‐driven target‐vessel revascularization) at 10 years. Among 566 patients with valid SS measurement at baseline, 240 (42.4%) had low SS, 200 (35.3%) had intermediate SS, and 126 (22.3%) had high SS. The 10‐year rates of major adverse cardiac or cerebrovascular events were not significantly different between PCI and CABG in low (21.6% versus 22.2%, P=0.97), intermediate (31.8% versus 22.2%; P=0.13), and high SS (46.2% versus 35.7%; P=0.31) (P‐for‐interaction=0.46). There were no significant interactions between SS categories and revascularization modalities for death (P=0.92); composite of death, myocardial infarction, or stroke (P=0.87); and target‐vessel revascularization (P=0.06). Higher SS categories were associated with higher risks for major adverse cardiac or cerebrovascular events in the PCI arm but not in the CABG arm.

Conclusions

Ten‐year clinical outcomes between PCI and CABG were not significantly different according to the SS. The SS was predictive of major adverse cardiac or cerebrovascular events after PCI but not after CABG.

Registration

URL: https://www.clinicaltrials.gov; Unique identifier: NCT03871127.

A Practical Approach to Hybrid Coronary Revascularization

Combined surgical and percutaneous coronary revascularization, ie, hybrid coronary revascularization (HCR) consists of surgical left internal mammary artery (LIMA) bypass to the left anterior descending artery (LAD) and percutaneous revascularization of other diseased coronary arteries. Developed as a 1-stage procedure, HCR has not been widely adopted by the cardiovascular community. The recommended minimally invasive approach through a small left thoracotomy incision is technically demanding, and same-day percutaneous revascularization requires a hybrid operating room that is not available in most hospitals. In this review, we consider present HCR protocols, barriers to widespread adoption of HCR, and we give special attention to the surgical approach for the LIMA graft to the LAD and the timing of percutaneous revascularization. We conclude that grafting the LIMA to the LAD through a median sternotomy approach and delaying the percutaneous revascularization may facilitate the widespread use of HCR in patients with multivessel coronary artery disease and a low to intermediate Synergy between Percutaneous Coronary Intervention with Taxus and Cardiac Surgery score.

The association between coronary graft patency and clinical status in patients with coronary artery disease

The concept of a direct association between coronary graft patency and clinical status is generally accepted. However, the relationship is more complex and variable than usually thought. Key issues are the lack of a common definition of graft occlusion and of a standardized imaging protocol for patients undergoing coronary bypass surgery. Factors like the type of graft, the timing of the occlusion, and the amount of myocardium at risk, as well as baseline patients' characteristics, modulate the patency-to-clinical status association. Available evidence suggests that graft occlusion is more often associated with non-fatal events rather than death. Also, graft failure due to competitive flow is generally a benign event, while graft occlusion in a graft-dependent circulation is associated with clinical symptoms. In this systematic review, we summarize the evidence on the association between graft status and clinical outcomes.

Arterial Grafts for Coronary Bypass

Observational and randomized evidence shows that arterial grafts have better patency rates than saphenous vein grafts (SVGs) in coronary artery bypass grafting. Observational studies suggest that the use of multiple arterial grafts is associated with longer postoperative survival, but this must be interpreted in the context of treatment allocation bias and hidden confounders intrinsic to the study designs. Recently, a pooled analysis of 6 randomized trials comparing the radial artery with the SVG as the second conduit and the largest randomized trial comparing the use of single and bilateral internal thoracic arteries have provided apparently divergent results about a clinical benefit with the use of >1 arterial conduit. However, both analyses have methodological limitations that may have influenced their results. At present, it is unclear whether the well-documented increased patency rate of arterial grafts translates into clinical benefits in the majority of patients undergoing coronary artery bypass grafting. A large randomized trial testing the arterial grafts hypothesis (ROMA [Randomized Comparison of the Clinical Outcome of Single Versus Multiple Arterial Grafts]) is underway and will report the results in a few years.

Implications of coronary artery bypass grafting and percutaneous coronary intervention on disease progression and the resulting changes to the physiology and pathology of the native coronary arteries

Myocardial revascularization can be achieved through 2 different methods: coronary artery bypass grafting (CABG) and percutaneous coronary intervention (PCI). Clinical trials comparing PCI and CABG generally use the composite end points of death, stroke, myocardial infarction and target vessel revascularization to determine superiority. Other effects of these interventions, including the preservation of normal coronary physiology, the response of the coronary tree to stressors and the response of the vessel wall to the revascularization intervention, are not routinely considered, but these may have significant implications for patients in the medium and long term. For PCI, relatively small differences in clinical outcomes have been reported between bare metal and drug-eluting stents, and the latter seems to have inconsistent and somewhat unpredictable effects on the vascular biology of the coronary arteries. In coronary bypass, the use of arterial conduits is associated with superior clinical outcomes, better long-term patency and the preservation of essentially normal coronary function after intervention. This review assembles the clinical, physiological, angiographic and pathological literature currently available and attempts to provide a more complete picture of the effects of CABG and PCI on coronary arteries.

RhoA/rho-kinase, nitric oxide and inflammatory response in LIMA during OPCABG with isoflurane preconditioning

Background

Grafting vessel with LIMA to the left anterior descending coronary artery plays a most important role in the long-term prognosis of OPCABG surgery. The aim of this study was to compare the effects of isoflurane preconditioning on miRs and mRNAs levels in the left internal mammary arterie (LIMA) graft with propofol in patients undergoing off-pump coronary artery bypass surgery (OPCABG).

Methods

Patients were randomly assigned to receive either propofol (n = 15), or interrupted isoflurane (n = 15). In group P, propofol administration was continued at 3–5 mg/kg/h intravenous injection for the duration of surgery. Five minutes prior to incision, patients of the isoflurane group (group Iso) received 2 cycles of 1 MAC isoflurane.

Results

miR-221 were significantly lower in group Iso (P < 0 .05). E-selectin mRNA, RhoA mRNA and ROK mRNA were significantly lower at specimens of LIMA in group Iso compared with those in group P patients (P < 0 .05). The expression of NOS3 mRNA was significantly higher in group Iso patients (P < 0 .05).

Conclusion

Our findings provide some insight that prior interrupted isoflurane administration could regulate miR-221, and downstream effectors (mRNAs) and resulted in actual attenuation of inflammation and spasm of LIMA in patients undergoing OPCABG surgery.

Trial registration

NCT No. (ClinicalTrials.gov): NCT02678650; Registration date: January 23, 2016.

Early Venous Stent Failure Predicted by Platelet Count and Neutrophil/Lymphocyte Ratio

BACKGROUND

Inflammation and platelet activation have been shown to be involved in acute thromobogenicity following venous occlusive conditions. The aim of this study was to identify the association of baseline platelet count and neutrophil/lymphocyte ratio (NLR) with venous stent failure. Methods and Results: Patients who underwent technically successful iliocaval venous stent placement with available baseline complete blood count and follow-up stent patency data were selected (n=50). Stent failure was defined as >50% stenosis or occlusion at follow-up angiography, contrast-enhanced CT, MRI or duplex US. Median patient age was 49.5 years (range, 13-76 years), and 62% were female. Median follow-up time was 10.2 months (range, 0.1-76.4 months). Stent failure occurred in 13 patients (26%) after a median of 1.2 months (range, 1 day-76.4 months). On multivariable-adjusted Cox modeling, baseline platelets (HR, 2.28; P=0.004) and WBC count (HR, 2.03; P=0.013) were significantly associated with stent failure on follow-up; neutrophils (HR, 16.10; P=0.050); and NLR (HR, 12.19; P=0.050) had borderline significance. Compared with patients without stent failure, those with early, but not late, stent failure had higher baseline platelets (P=0.031) and neutrophils (P=0.025), and NLR (P=0.026).

CONCLUSIONS

Baseline platelet count and NLR are associated with early but not late failure of iliocaval venous stents. This suggests different pathophysiologic mechanisms and a role for both platelet activation and inflammatory mechanisms in early rather than late stent thrombosis. Future research is needed to better explain this novel finding.

Percutaneous coronary intervention vs. coronary artery bypass grafting for left main revascularization: an updated meta-analysis

Aims

The optimal revascularization strategy for left main coronary artery disease (LMD) remains controversial, especially with two recent randomized controlled trials showing conflicting results. We sought to address this controversy with our analysis.

Methods and results

Comprehensive literature search was performed. We compared percutaneous coronary intervention (PCI) and coronary artery bypass grafting (CABG) for LMD revascularization using standard meta-analytic techniques. A 21% higher risk of long-term major adverse cardiac and cerebrovascular event [MACCE; composite of death, myocardial infarction (MI), stroke, and repeat revascularization] was observed in patients undergoing PCI in comparison with CABG [risk ratio (RR) 1.21, 95% confidence interval (CI) 1.05-1.40]. This risk was driven by higher rate of repeat revascularization in those undergoing PCI (RR 1.61, 95% CI 1.34-1.95). On the contrary, MACCE rates at 30 days were lower in PCI when compared with CABG (RR 0.55, 95% CI 0.39-0.76), which was driven by lower rates of stroke in the PCI arm (RR 0.41, 95% CI 0.17-0.98). At 1 year, lower stroke rates (RR 0.21, 95% CI 0.08-0.59) in the PCI arm were balanced by higher repeat revascularization rates in those undergoing PCI (RR 1.78, 95% CI 1.33-2.37), resulting in a clinical equipoise in MACCE rates between the two revascularization strategies. There was no difference in death or MI between PCI when compared with CABG at any time point.

Conclusion

Outcomes of CABG vs. PCI for LMD revascularization vary over time. Therefore, individualized decisions need to be made for LMD revascularization using the heart team approach.

Long term outcomes of drug-eluting stent versus coronary artery bypass grafting for left main coronary artery disease: a meta-analysis

Background

It is still controversial whether percutaneous coronary intervention with drug-eluting stent (DES) is safe and effective compared to coronary artery bypass graft surgery (CABG) for unprotected left main coronary artery (ULMCA) disease at long-term follow up (≥ 3 years).

Methods

Eligible studies were selected by searching PubMed, EMBASE, and Cochrane Library up to December 6, 2016. The primary endpoint was a composite of death, myocardial infarction (MI) or stroke during the longest follow-up. Death, cardiac death, MI, stroke and repeat revascularization were the secondary outcomes.

Results

Four randomized controlled trials and twelve adjusted observational studies involving 14,130 patients were included. DES was comparable to CABG regarding the occurrence of the primary endpoint (HR = 0.94, 95% CI: 0.86–1.03). Besides, DES was significantly associated with higher incidence of MI (HR = 1.56, 95% CI: 1.09–2.22) and repeat revascularization (HR = 3.09, 95% CI: 2.33–4.10) compared with CABG, while no difference was found between the two strategies regard as the rate of death, cardiac death and stroke. Furthermore, DES can reduce the risk of the composite endpoint of death, MI or stroke (HR = 0.80, 95% CI: 0.67–0.95) for ULMCA lesions with SYNTAX score ≤ 32.

Conclusions

Although with higher risk of repeat revascularization, PCI with DES appears to be as safe as CABG for ULMCA disease at long-term follow up. In addition, treatment with DES could be an alternative interventional strategy to CABG for ULMCA lesions with low to intermediate anatomic complexity.