Drug-Eluting Stenting for Unprotected Left Main Coronary Artery Disease

Left Main Percutaneous Coronary Intervention

Significant unprotected left main stem (ULMS) disease is in approximately 5% to 7% of patients undergoing coronary angiography. Historically, coronary artery bypass grafting has been the gold standard treatment of these patients. With recent advances in stent technology, adjunctive pharmacotherapy, and operator experience, percutaneous coronary intervention (PCI) is increasingly regarded as a viable alternative treatment option, especially in patients with favorable coronary anatomy (low and intermediate SYNTAX (Synergy Between Percutaneous Coronary Intervention with TAXUS and Cardiac Surgery) scores). This article aims to discuss the evidence supporting PCI for ULMS disease, current guidelines, and technical aspects.

Approach to Treatment of Bifurcation Lesions

OPINION STATEMENT

Bifurcation lesions are frequently encountered in the cath lab [1] and remain a challenge for conventional percutaneous coronary intervention (PCI) techniques. Although provisional stenting remains the default approach for most bifurcation lesions [2-6], the two-stent technique is more appropriate in certain situations. If a two-stent strategy is selected, then final kissing balloon inflation (KBI) should be performed. Adjunctive assessment with intravascular imaging (intravascular ultrasound (IVUS)/optical coherence tomography (OCT)) and physiologic testing (fractional flow reserve, FFR) should be performed liberally. Drug-eluting stents (DES) are typically utilized to reduce the risk of restenosis in bifurcation disease.

Drug-eluting stents in unprotected left main coronary artery disease

Though coronary bypass graft surgery (CABG) has traditionally been the cornerstone of therapy in patients with unprotected left main coronary artery (ULMCA) disease, recent evidence supports the use of percutaneous coronary intervention in appropriate patients. Indeed in patients with ULMCA disease, drug-eluting stents (DES) have shown similar incidence of hard end points, fewer periprocedural complications and lower stroke rates compared with CABG, though at the cost of increased revascularization with time. Furthermore, the availability of newer efficacious and safer DES as well as improvements in diagnostic tools, percutaneous techniques and, importantly, a better patient selection, allowed percutaneous coronary intervention a viable alternative to CABG of left main-patients with low disease complexity; however, even in this interventional era characterized by efficacious DES, patients with ULMCA disease remain a challenging high-risk population where outcomes strongly depend on clinical characteristics, anatomical disease complexity and extension and operator's experience. This review summarizes the role of DES in ULMCA disease patients.

One-Year Outcomes After Everolimus-Eluting Stents Implantation in Ostial Lesions of Left Anterior Descending Coronary Arteries

Background

In recent years, stents are increasingly used in variety of coronary lesions. Ostial lesion of left anterior descending coronary artery (LAD) however remains a challenge area because of the invariable involvement of distal left main coronary artery (LMCA). This study was designed to evaluate the clinical and angiographic outcomes of everolimus-eluting stent (EES) implantation for ostial LAD.

Methods

EESs were implanted in 45 consecutive patients with ostial LAD stenoses. For complete lesion coverage, stent positing was extended into the distal LMCA in 6 patients (13.3%) with intermediated LMCA narrowing. We assess MACE during one-year follow-up.

Results

In-hospital success rate was 100%; neither cardiac death nor stent thrombosis in our patients, but two patients had myocardial infarction in non-related coronary artery during follow-up. Two patients had angiographic restenosis and underwent TLR. The cumulative MACE-free survival rate was 95.6% at one year.

Conclusion

EES was in ostial LAD lesions with complete lesion coverage achieving high procedural success rate and acceptable clinical outcomes during one-year follow-up period.

Percutaneous revascularization of left main: role of imaging, techniques, and adjunct pharmacology

Refinement of interventional techniques, adjunctive pharmacological therapy, and the introduction of drug-eluting stents have fostered new interest for the percutaneous treatment of unprotected left main coronary artery (ULMCA) stenosis. Several observational registries, some randomized trials and several meta-analyses have consistently shown no difference in mortality and myocardial infarction between percutaneous coronary intervention (PCI) and coronary artery bypass graft (CABG) surgery in patients with ULMCA stenosis, but a higher rate of target vessel revascularization in patients treated with PCI. As a consequence, PCI of ULMCA stenosis has been upgraded to class IIa or IIb indication in the current European or American practice guidelines. However, several critical issues should be properly addressed when pursuing a percutaneous strategy for the treatment of ULMCA stenosis, such as the use of IVUS for procedural guidance, assessment of disease location, optimal technique for distal ULMCA stenosis, risk of stent thrombosis, optimal duration of dual antiplatelet therapy, and the most appropriate strategy for post-procedure follow up. Multidisciplinary team approach remains essential to provide a balanced information to the patient and to offer the beast treatment option.

Surgery for chronic total occlusion of the left main coronary artery

BACKGROUND AND OBJECTIVES

Chronic total occlusion of the left main coronary artery (LMCA) is a rare condition, and the information on surgical experiences is limited. Although total occlusion of the LMCA is accompanied by well-developed collateral circulation, the condition of circulation is unstable during manipulation of the heart. We report our experience with revascularization in cases with total occlusion of the LMCA using the on-pump beating-heart (OnP-BH) technique.

DESIGN AND SETTING

Retrospective case review of patients treated at The First Affiliated Hospital of China Medical University over a 10-year period (1999 to 2009).

PATIENTS AND METHODS

The on-pump coronary artery bypass grafting with the beating heart was applied to 8 patients with chronic total occlusion of the LMCA. The extracorporeal circulation period, intubation duration, intensive care unit stay period, discharge period, preoperative and postoperative treatments, and follow-up were observed.

RESULTS

The mean extracorporeal circulation period was 80.4 (19.7) minutes. The mean intubation duration was 13.0 (4.6) hours. The mean intensive care unit stay period was 3.2 (0.7) days, and the mean discharge period was 16.8 (3.3) days. No perioperative myocardial infarction occurred. The mean follow-up period was 50.9 (34.8) months. All patients were asymptomatic, and no deaths were recorded during the follow-up period. The results of echocardiography showed improvement in the left ventricular function.

CONCLUSIONS

The OnP-BH myocardial revascularization seems to be a valid alternative for chronic total occlusion of the LMCA.

Treatment of patients with left main coronary artery disease

OPINION STATEMENT

Considering lesion priority and its clinical consequences, coronary artery bypass grafting (CABG) has been a treatment of choice for revascularization in patients with significant left main coronary artery (LMCA) disease, However, with remarkable advancements in techniques of percutaneous coronary intervention (PCI), supporting devices, and adjunctive pharmacologic therapy, PCI with stenting has emerged to be a less invasive and feasible revascularization treatment for these patients. The cumulative evidence suggests that the safety outcomes such as mortality or composite of death, myocardial infarction, and stroke are similar among PCI and CABG, with the only difference being the rate of repeat revascularization. Based on these data, the current guideline of revascularization of LMCA disease has adopted an increasing off-label experience with stenting and clinical studies and been updated to partly approve PCI as a viable alternative (in level of class IIb) in selected patients. The choice of PCI or CABG for unprotected LMCA disease depends on several clinical and anatomic features, ensuring crucial patient selection to be a cornerstone for achieving favorable long-term outcomes. In patients with very complex anatomic features and concomitant diffuse multivessel disease, CABG is preferred so as to avoid procedural and future thrombotic risks and to provide more complete revascularization. By contrast, in patients with relatively simple LMCA disease, such as ostial/shaft LMCA disease, isolated LMCA disease (with or without one or two-vessel involvement), and LMCA disease with low SYNTAX score, PCI is an alternative, and in some cases a preferred, strategy to reduce surgical risks (eg, stroke and in-hospital events following major surgery). For the future, ongoing large clinical trials might also boost interventional cardiologists to select PCI with stenting as an alternative revascularization strategy for unprotected LMCA disease. This evidence will most likely change the current clinical practice and guidelines of optimal revascularization strategy for unprotected LMCA disease.

Revascularization of left main coronary artery disease

Coronary artery disease with left main stenosis is associated with the highest mortality of any coronary lesion. Studies in the 1970s and 1980s comparing coronary artery bypass grafting (CABG) and medical therapy showed a significant survival benefit with revascularization. In the angioplasty era, initial experience with percutaneous intervention was associated with poor clinical outcomes. As a result, percutaneous coronary intervention (PCI) was restricted to patients who were considered inoperable, or those with prior CABG with a functional graft to the left anterior descending or circumflex artery ("protected left main disease"). With the introduction of drug-eluting stents, there are new studies demonstrating comparable survival in patients who were revascularized using PCI and CABG, although percutaneous revascularization is associated with a higher rate of repeat revascularization. In the SYNTAX (Synergy between PCI with Taxus and Cardiac Surgery) trial, the combined incidence of death, myocardial infarction, and stroke was similar between the CABG and PCI groups; however, the stroke rate was higher in the CABG group. The degree and extent of disease as defined by the SYNTAX scoring system has allowed for stratification of risk and improved assignment of patients with left main stenosis to either PCI or CABG.

Percutaneous coronary intervention with stent implantation versus coronary artery bypass surgery for treatment of left main coronary artery disease: is it time to change guidelines?

On the basis of clinical trials comparing coronary-artery bypass grafting (CABG) with medical therapy, current guideline recommend CABG as the treatment of choice for patients with asymptomatic ischemia, stable angina, or unstable angina/non-ST elevation myocardial infarction who have left main coronary artery disease. Percutaneous coronary intervention can be selectively performed in patients who are candidates for revascularization but who are ineligible for CABG. However, because of advances in periprocedural and postprocedural medical care in patients undergoing either CABG or percutaneous coronary intervention with stenting, new evaluation, and a review of current indications, may be required to determine the standard of care for patients with left main coronary artery disease. Current evidences indicate that stenting results in mortality and morbidity rates that compared favorably with those seen after CABG, suggesting that a current guideline (the Class III recommendation of percutaneous coronary intervention for unprotected left main coronary artery disease) may no longer be justified. Data from several extensive registries and a large clinical trial may have prompted many interventional cardiologists to select percutaneous coronary intervention with stenting as an alternative revascularization strategy for such patients. In addition, these data may inform future guidelines and support the need for well-designed, adequately powered, prospective, randomized trials comparing the 2 revascularization strategies. The cumulative evidence from ongoing and future clinical trials will change the current clinical practice of revascularization for unprotected left main coronary artery disease, which was introduced several decades ago and which has continued to date without major revision.

Two-year outcomes of the sirolimus-eluting stent according to unprotected left main lesion

BACKGROUND

The data of long-term outcomes of sirolimus-eluting stent (SES) according to lesion location of unprotected left main coronary artery (LMCA) is scarce.

HYPOTHESIS

The purpose of this study was to evaluate the long-term outcomes after implantation of the SES in LMCA.

METHODS

A total of 84 patients (51 males) who had undergone SES implantation for the treatment of native LMCA stenosis were enrolled. The patients were divided into 2 groups based on angiographic lesion location: those with significant stenosis in the ostium and/or body (group 1; n = 39) and those involving bifurcation (group 2; n = 45).

RESULTS

All of the group 1 patients were treated with simple lesion coverage while different stenting techniques were used in group 2 (cross-over: 44.8%, T: 6.7%, kissing: 37.8%, and crush techniques: 11.1%). The 8-month quantitative angiographic findings and in-hospital and 2 year rates of major adverse cardiac events (MACE) were compared between the 2 groups. Although angiographic success and in-hospital MACE rates were similar in both groups with 1 cardiac death due to acute stent thrombosis in group 2, at 2-year follow-up, the MACE rate was significantly higher in group 2 than in group 1 at 2 years (22.2% vs 2.6%, respectively, P = 0.008). Coronary angiography revealed a significantly higher binary restenosis rate in group 2 compared with group 1 (20% vs 0%, respectively, P = 0.003).

CONCLUSIONS

Interventional treatment using SES in left main lesions showed favorable short-term and long-term outcomes in selected patients with lesion location being an important determinant of clinical and angiographic outcomes.

Effectiveness of drug-eluting stent implantation for patients with unprotected left main coronary artery stenosis

This study was aimed to evaluate outcomes of patients with unprotected left main coronary artery (LMCA) stenosis who were treated with drug-eluting stents. Sixty-three consecutive patients with unprotected LMCA stenosis were treated with sirolimus-eluting stents in 52 (83%) patients and paclitaxel-eluting stents in 11 (17%) patients, in whom percutaneous intervention was considered the sole alternative because of high surgical risk and/or patient preference. Urgent percutaneous coronary intervention within 24 hours after angiography was performed in 6 (10%) patients. The patients were predominantly at high surgical risk with 35 (56%) having EuroSCORE >6 and 39 (62%) having Parsonnet score >15. Involvement of the distal LMCA was observed in 46 (73%) patients. Procedural success was achieved in all patients. Intravascular ultrasound was used in 51 (81%) patients. Single-stenting strategy was adopted in 36 (78%) patients with bifurcation stenosis. There were no death, Q-wave myocardial infarction, stent thrombosis, or urgent repeat revascularization events during hospitalization. Over a mean follow-up of 11.7 +/- 7.7 months, 18 (29%) patients experienced major adverse cardiac events, including 3 (5%) deaths, 7 (11%) myocardial infarctions, and 10 (16%) target lesion revascularizations. Stent thrombosis developed in 1 (0.6%) patient at 35 days after the procedure. Bifurcation involvement was an independent predictor of major adverse cardiac events by multivariate analysis (hazard ratio 12.90, 95% confidence interval 1.36 to 122.45, p = 0.0259). In conclusion, drug-eluting stent placement for unprotected LMCA stenosis may be a feasible therapeutic alternative in patients at high surgical risk. However, bifurcation stenosis remains a significant predictor of unfavorable clinical outcome.

Percutaneous coronary artery stenting of unprotected left main coronary artery disease using drug-eluting stents: the initial Baylor University Medical Center experience

Significant narrowing of the left main coronary artery is a high-risk condition with significant mortality risk. Bypass surgery is the current gold-standard treatment for unprotected left main (ULM) disease. Stenting utilizing drug-eluting stents (DES) is another therapeutic option for patients with ULM disease considered too high risk for bypass surgery or for patients who simply refuse bypass surgery. We have had great initial success with ULM stenting using DES in 10 selected patients at Baylor University Medical Center. Ongoing multicenter, international randomized studies comparing percutaneous coronary intervention with DES and bypass surgery will shed more light on the best treatment strategy for ULM coronary disease.

Transition from bare metal to drug eluting stenting in contemporary US practice: effect on incidence and predictors of clinically driven target lesion revascularization

BACKGROUND

The performance of drug eluting stents (DES) and impact on every day practice in the USA, where complex, nonselective cases are the rule, remain unknown.

METHODS

The Brigham and Women's Hospital interventional experience in the bare metal stents (BMS) (6/2002 to 2/2003) and after abrupt and near universal adoption of DES (4/2003 to 9/2004) were compared. Demographic, procedural and in-hospital outcomes for all consecutive cases where investigated. Predictors and angiographic characteristics of patients returning for clinically driven target lesion revascularization (TLR) in both eras were analyzed.

RESULTS

Of 2,555 DES cases (3,061 lesions, 87.9% Cypher, 12.1% Taxus), 47 underwent TLR during follow-up (68 lesions, 2.2%). Of the 1,731 BMS cases (1,798 lesions), 162 underwent clinically indicated TLR (209 lesions, 11.6%), representing an 81% DES era TLR risk reduction. Multivariate predictors of TLR in the DES era: left main lesion (LM) (odds ratio (OR) 7.65, 95% confidence interval (CI) 3.33-17.53, P<0.01, treatment of restenosis (OR 5.96, CI 3.21-11.08, P<0.01), and diabetes (OR 1.68, CI 0.92-3.04, P=0.07). Predictors of restenosis in the BMS era included additional clinical, lesion, and stent characteristics, while LM lesion was absent. Angiographic patterns of stent restenosis differed in the DES (focal) and BMS (diffuse) era.

CONCLUSIONS

The transition from BMS to DES in the setting of a large USA hospital practice is safe and associated with significant reduction in clinically driven TLR. Treatment of specific lesions types (repeat restenosis, distal LM) and diabetic patients remain suboptimal and warrant further investigation.

Favorable Long-Term Outcome After Drug-Eluting Stent Implantation in Nonbifurcation Lesions That Involve Unprotected Left Main Coronary Artery

Background— The presence of a lumen narrowing at the ostium and the body of an unprotected left main coronary artery but does not require bifurcation treatment is a class I indication of surgical revascularization.

Methods and Results— A total of 147 consecutive patients who had a stenosis in the ostium and/or the midshaft of an unprotected left main coronary artery (treatment of the bifurcation not required) and were electively treated with percutaneous coronary intervention and sirolimus-eluting stents (n=107) or paclitaxel-eluting stents (n=40) in 5 centres were included in this registry. In 72 patients (almost 50%), intravascular ultrasound guidance was performed. Procedural success was achieved in 99% of the patients; in 1 patient with stenosis in the left main coronary artery ostium, a >30% residual stenosis persisted at the end of the procedure, and the patient was referred for coronary artery bypass graft surgery. During hospitalization, no patients experienced a Q-wave myocardial infarction or died. One patient died 19 days after the procedure because of pulmonary infection. At long-term clinical follow-up (886±308 days), 5 patients had died; 7 patients had target vessel revascularization (5 repeat percutaneous coronary interventions and 2 coronary artery bypass graft surgeries), and of these only 1 patient had a target lesion revascularization. Angiographic follow-up was performed in 106 patients (72%) with a late loss of −0.01 mm. Restenosis in the left main trunk occurred only in 1 patient (0.9%).

Conclusions— Percutaneous coronary intervention with sirolimus-eluting stents or paclitaxel-eluting stents implantation in nonbifurcation left main coronary artery lesions appears safe with a long-term major adverse clinical event rate of 7.4% and a restenosis rate of 0.9%.

Left main coronary artery stenosis: state-of-the-art

Patients with stenosis of the left main coronary artery present difficult challenges. The risks associated with this lesion have been known since the early days of angiography when patients were found to have increased mortality during follow-up. This information led to the general guidelines that surgical revascularization should be considered the treatment of choice in patients with significant left main coronary artery stenosis. Current advances in invasive cardiology have brought important information to the field. Intravascular ultrasound is now used routinely to evaluate angiographically indeterminate lesions with criteria now set forward as to what constitutes an indication for revascularization. Stents have even further dramatically changed the landscape. There are substantial issues, however, that need to addressed. These include the following: (1) the effect of specific lesion location on outcome - it is known that patients with distal bifurcation left main disease have worse outcome; (2) the potential for subacute thrombosis of the left main coronary artery; (3) the impact of left ventricular function and patient comorbidities irrespective of the degree and location of left main coronary artery stenosis; and (4) the risk-benefit ratio of stenting versus coronary artery bypass graft surgery. These issues are currently being addressed in two seminally important trials including the SYNTAX trial, which randomizes patients with left main and/or three-vessel disease to either coronary artery bypass graft surgery or a TAXUS drug-eluting stent. This trial is in the final stages of patient recruitment and will have important implications for the field. The other trial is the COMBAT trial, which is focused exclusively on left main coronary artery stenosis and randomizes patients with left main coronary artery disease either to a Sirolimus-eluting stent (Cypher, Johnson and Johnson Cordis, USA) or to coronary artery bypass graft surgery. The field of left main coronary artery disease continues to expand in terms of the evidence available for optimal patient evaluation and selection of treatment modalities.

Stenting of unprotected left main coronary artery stenosis

Unprotected left main stenosis greater than 50% has traditionally been managed with coronary artery bypass surgery. There is now emerging evidence to support a percutaneous strategy adopting drug-eluting stents, especially in patients at high risk for surgery. This paper will review recent outcomes of both bare-metal and drug-eluting stent use for unprotected left main stenosis and summarise results of an Australian registry. Results of studies comparing the percutaneous approach to surgery will also be reviewed together with ESC and AHA/ACC current guidelines. Although percutaneous intervention of unprotected left main has been shown to be a safe and feasible procedure, unanswered questions remain. Large multi-centre randomised trials underway comparing percutaneous to surgical intervention will help clarify these ongoing issues.

Impact of three-dimensional characteristics of the left main coronary artery bifurcation on outcome of crush stenting

BACKGROUND

Crush stenting with drug-eluting stents is used to treat left main coronary artery (LMCA) bifurcations. However, the rate of restenosis at the left circumflex (LCX) artery ostium is high. The impact of the three-dimensional (3D) structure of LMCA bifurcation on the outcome of crush stenting with respect to restenosis has not been described.

OBJECTIVES

This study examined the stent expansion, deformity, overlapping, and apposition after crush stenting of LMCA bifurcations.

METHODS

Bare metal stents were crushed at LMCA bifurcations in a 3D model that reproduced actual angles, such that the stent deployed from the LMCA to the left anterior descending (LAD) artery crushed the stent deployed from the LMCA to the LCX, followed by kissing balloon inflation. The stents were inspected under fluoroscopy and endoscopy. The effect of the bifurcation angle on stent expansion was also examined.

RESULTS

In the 3D model, one stent overlapped the other in the distal LMCA, in contrast to the nearly parallel position of the stents observed in a separate two-dimensional model. When the LAD stent overlapped the LCX stent, the latter was crushed on the myocardial side of the vessel, and an unstented segment was observed on the nonmyocardial side, at the LCX ostium. When the overlap was reversed, the LCX stent was crushed on the nonmyocardial side and an unstented segment was observed on the myocardial side. A narrow LMCA-LCX angle was associated with less expansion of the LCX stent at the ostium than more distally, and with a higher likelihood of incomplete stent apposition.

CONCLUSIONS

Overlap of the LAD stent over, as opposed to under, the LCX stent was associated with close apposition of the stent to the vessel on the myocardial side, at the ostium of the LCX artery, where atherosclerotic plaques are likely to be present. The spatial plaque burden and bifurcation angle should be closely examined before crush stenting, and segments should not be left unstented over large plaques.

Complex Coronary Interventions: Unprotected Left Main and Bifurcation Lesions

Percutaneous coronary intervention has moved forward with great speed since the advent of stents and now more recently the introduction of drug-eluting technologies. This has seen the modern interventional cardiologist tackle more and more complex coronary lesions, of which unprotected left main (ULM) and bifurcations still remain challenging and controversial. ULM coronary artery stenosis traditionally remains a surgical indication although there have been recent reports and studies demonstrating the feasibility of a percutaneous strategy in select patient groups. Furthermore, drug-eluting stents have shown great benefit in reducing the problem of restenosis and have also become the mainstay treatment modality for bifurcation lesions with a choice between one- or two-stent strategies determined by the extent of disease burden in the main vessel and side branch and the response of the side branch ostium following treatment of the main vessel. This article will provide a contemporary review of percutaneous intervention for these two lesion subsets and describe the relative merits of each of the different strategies in current use with a glimpse into what the future may hold.