Computing Methods for Composite Clinical Endpoints in Unprotected Left Main Coronary Artery Revascularization: A Post Hoc Analysis of the DELTA Registry

Prognostic value of pan immune-inflammation value in patients undergoing unprotected left main coronary artery stenting

Aim: This study aimed long-term prognostic factors for percutaneous coronary intervention (PCI) in left main coronary artery (LMCA) disease, focusing on inflammatory parameters like Pan Immune-Inflammation Value (PIV) and Systemic Immune-Inflammation Index (SII).Materials & methods: This retrospective, observational study involved 121 patients receiving unprotected LMCA PCI.The study's primary end point was MACE, including all-cause death, repeat revascularization and myocardial reinfarction.Results: The PIV and SII scores emerged as independent predictors of MACE occurrence in patients undergoing PCI for unprotected LMCA disease (p:0.045,p:0.048;respectively).In addition, age, ejection fraction, creatinine, shock presentation and the residual syntax score were identified as significant independent predictors of MACE in both models.Conclusion: This study showed a significant, independent correlation between PIV, SII and MACE in patients undergoing PCI for LMCA disease, with PIV showing slightly better predictive capability than SII.

Application of the Win Ratio Method in the ENGAGE AF-TIMI 48 Trial Comparing Edoxaban With Warfarin in Patients With Atrial Fibrillation

BACKGROUND

Cardiovascular trials often use a composite end point and a time-to-first event model. We sought to compare edoxaban versus warfarin using the win ratio, which offers data complementary to time-to-first event analysis, emphasizing the most severe clinical events.

METHODS

ENGAGE AF-TIMI 48 (Effective Anticoagulation With Factor Xa Next Generation in Atrial Fibrillation-Thrombolysis in Myocardial Infarction 48) was a double-blind, randomized trial in which patients with atrial fibrillation were assigned 1:1:1 to a higher dose edoxaban regimen (60/30 mg daily), a lower dose edoxaban regimen (30/15 mg daily), or warfarin. In an exploratory analysis, we analyzed the trial outcomes using an unmatched win ratio approach. The win ratio for each edoxaban regimen was the total number of edoxaban wins divided by the number of warfarin wins for the following ranked clinical outcomes: 1: death; 2: hemorrhagic stroke; 3: ischemic stroke/systemic embolic event/epidural or subdural bleeding; 4: noncerebral International Society on Thrombosis and Haemostasis major bleeding; and 5: cardiovascular hospitalization.

RESULTS

21 105 patients were randomized to higher dose edoxaban regimen (N=7035), lower dose edoxaban regimen (N=7034), or warfarin (N=7046), yielding >49 million pairs for each treatment comparison. The median age was 72 years, 38% were women, and 59% had prior vitamin K antagonist use. The win ratio was 1.11 (95% CI, 1.05-1.18) for higher dose edoxaban regimen versus warfarin and 1.11 (95% CI, 1.05-1.18) for lower dose edoxaban regimen versus warfarin. The favorable impacts of edoxaban on death (34% of wins) and cardiovascular hospitalization (41% of wins) were the major contributors to the win ratio. Results consistently favored edoxaban in subgroups based on creatine clearance and dose reduction at baseline, with heightened benefit among those without prior vitamin K antagonist use.

CONCLUSIONS

In a win ratio analysis of the ENGAGE AF-TIMI 48 trial, both dose regimens of edoxaban were superior to warfarin for the net clinical outcome incorporating ischemic and bleeding events. As the win ratio emphasizes the most severe clinical events, this analysis supports the superiority of edoxaban over warfarin in patients with atrial fibrillation.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT00781391.

Generalized Pairwise Comparisons to Assess Treatment Effects: JACC Review Topic of the Week

A time-to-first-event composite endpoint analysis has well-known shortcomings in evaluating a treatment effect in cardiovascular clinical trials. It does not fully describe the clinical benefit of therapy because the severity of the events, events repeated over time, and clinically relevant nonsurvival outcomes cannot be considered. The generalized pairwise comparisons (GPC) method adds flexibility in defining the primary endpoint by including any number and type of outcomes that best capture the clinical benefit of a therapy as compared with standard of care. Clinically important outcomes, including bleeding severity, number of interventions, and quality of life, can easily be integrated in a single analysis. The treatment effect in GPC can be expressed by the net treatment benefit, the success odds, or the win ratio. This review provides guidance on the use of GPC and the choice of treatment effect measures for the analysis and reporting of cardiovascular trials.

Making Sense of Composite Endpoints in Clinical Research

Multiple drugs currently used in clinical practice have been approved by regulatory agencies based on studies that utilize composite endpoints. Composite endpoints are appealing because they reduce sample size requirements, follow-up periods, and costs. However, interpreting composite endpoints can be challenging, and their misuse is not uncommon. Incorrect interpretation of composite outcomes can lead to misleading conclusions that impact patient care. To correctly interpret composite outcomes, several important questions should be considered. Are the individual components of the composite outcome equally important to patients? Did the more and less important endpoints occur with similar frequency? Do the component endpoints exhibit similar relative risk reductions? If these questions receive affirmative answers, the use and interpretation of the composite endpoint would be appropriate. However, if any component of the composite endpoint fails to satisfy the aforementioned criteria, interpretation can become difficult, necessitating additional steps. Regulatory agencies acknowledge these challenges and have specific considerations when approving drugs based on studies employing composite endpoints. In conclusion, composite endpoints are valuable tools for evaluating the efficacy and net clinical benefit of interventions; however, cautious interpretation is advised.

Risk Burden of Coronary Perforation in Chronic Total Occlusion Recanalization: Latin American CTO Registry Analysis

Background

Coronary perforation is a life‐threatening complication of acute percutaneous coronary intervention (PCI) for chronic total occlusions (CTO), but data on midterm outcomes are limited.

Methods and Results

Data from LATAM (Latin American)‐CTO Registry (57 centers; 9 countries) were analyzed. We assessed the risk of 30‐day, 1‐year major adverse cardiac events of coronary perforation using time‐to‐event and weighted composite end point analysis having CTO PCI without perforation as comparators. Additionally, we studied the independent predictors of perforation in these patients. Of 2054 patients who underwent CTO PCI between 2015 and 2018, the median Multicenter CTO Registry in Japan and Prospective Global Registry for the Study of Chronic Total Occlusion Intervention‐Chronic total occlusions scores were 2.0 (1.0–3.0) and 1.0 (0.0–2.0), respectively. The perforation rate was 3.7%, of which 55% were Ellis class 1. After 1‐year coronary perforation had higher major adverse cardiac events rates (24.9% versus 13.3%; P<0.01). Using weighted composite end point, perforation was associated with increased bleeding and ischemic events at 6 months (P=0.04) and 1 year (P<0.01). We found as independent predictors associated with coronary perforation during CTO PCI: maximum activated clotting time (P<0.01), Multicenter CTO Registry in Japan score ≥2 (P=0.05), antegrade knuckle wire (P=0.04), and right coronary artery CTO PCI (P=0.05).

Conclusions

Coronary perforation was infrequent and associated with anatomical and procedural complexity, resulting in higher risk of hemorrhagic and ischemic events. Landmark and weighted analysis showed a sustained burden of major events between 6 months and 1 year follow‐up.

Statistical methods for composite endpoints

Composite endpoints are commonly used in clinical trials, and time-to-first-event analysis has been the usual standard. Time-to-first-event analysis treats all components of the composite endpoint as having equal severity and is heavily influenced by short-term components. Over the last decade, novel statistical approaches have been introduced to overcome these limitations. We reviewed win ratio analysis, competing risk regression, negative binomial regression, Andersen-Gill regression, and weighted composite endpoint (WCE) analysis. Each method has both advantages and limitations. The advantage of win ratio and WCE analyses is that they take event severity into account by assigning weights to each component of the composite endpoint. These weights should be pre-specified because they strongly influence treatment effect estimates. Negative binomial regression and Andersen-Gill analyses consider all events for each patient -rather than only the first event - and tend to have more statistical power than time-to-first-event analysis. Pre-specified novel statistical methods may enhance our understanding of novel therapy when components vary substantially in severity and timing. These methods consider the specific types of patients, drugs, devices, events, and follow-up duration.

Prioritised endpoints for device-based hypertension trials: the win ratio methodology

AIMS

Multiple endpoints with varying clinical relevance are available to establish the efficacy of device-based treatments. Given the variance among blood pressure measures and medication changes in hypertension trials, we performed a win ratio analysis of outcomes in a sham-controlled, randomised trial of renal denervation (RDN) in patients with uncontrolled hypertension despite commonly prescribed antihypertensive medications. We propose a novel prioritised endpoint framework for determining the treatment benefit of RDN compared with sham control.

METHODS AND RESULTS

We analysed the SPYRAL HTN-ON MED pilot study data using a prioritised hierarchical endpoint comprised of 24-hour mean ambulatory systolic blood pressure (SBP), office SBP, and medication burden. A generalised pairwise comparisons methodology (win ratio) was extended to examine this endpoint. Clinically relevant thresholds of 5 and 10 mmHg were used for comparisons of ambulatory and office SBP, respectively, and therefore to define treatment "winners" and "losers". For a total number of 1,596 unmatched pairs, the RDN subject was the winner in 1,050 pairs, the RDN subject was the loser in 378 pairs, and 168 pairs were tied. The win ratio in favour of RDN was 2.78 (95% confidence interval [CI]: 1.58 to 5.48; p<0.001) and corresponding net benefit statistic was 0.42 (95% CI: 0.20 to 0.63). Sensitivity analyses performed with differing blood pressure thresholds and according to drug adherence testing demonstrated consistent results.

CONCLUSIONS

The win ratio method addresses prior limitations by enabling inclusion of more patient-oriented results while prioritising those endpoints considered most clinically important. Applying these methods to the SPYRAL HTN-ON MED pilot study (ClinicalTrials.gov Identifier: NCT02439775), RDN was determined to be superior regarding a hierarchical endpoint and a "winner" compared with sham control patients.

Complete Revascularization in Acute and Chronic Coronary Syndrome

In patients with multivessel disease, complete revascularization (CR) is the most biologically plausible approach irrespective of definition or type or clinical setting (acute or chronic coronary syndrome [ACS or CCS]). It aims at minimizing residual ischemia, relieving symptoms and reducing the risk of future cardiovascular events. Large evidence supports CR benefits in ACS, predominantly ST-segment elevation myocardial infarction, except cardiogenic shock, although optimal assessment and timing remain debated. In patients with CCS, when revascularization is indicated, a functional CR should be attempted. Therefore, heart-team is crucial in selecting the ideal strategy for each patient to optimize decision-making.

Comparative Methodological Assessment of the Randomized GLOBAL LEADERS Trial Using Total Ischemic and Bleeding Events

BACKGROUND

Time-to-first-event analysis considers only the first event irrespective of its severity. There are several methods to assess trial outcomes beyond time-to-first-event analysis, such as analyzing total events and ranking outcomes. In the GLOBAL LEADERS study, time-to-first-event analysis did not show superiority of ticagrelor monotherapy following one-month dual antiplatelet therapy (DAPT) after percutaneous coronary intervention to conventional 12-month DAPT followed by aspirin monotherapy in the reduction of the primary composite end point of all-cause mortality or new Q-wave myocardial infarction. This study sought to explore various analytical approaches in assessing total ischemic and bleeding events after percutaneous coronary intervention in the GLOBAL LEADERS study.

METHODS AND RESULTS

Total ischemic and bleeding events were defined as all-cause mortality, any stroke, any myocardial infarction, any revascularization, or Bleeding Academic Research Consortium grade 2 or 3 bleeding. We used various analytical approaches to analyze the benefit of ticagrelor monotherapy over conventional DAPT. For ischemic and bleeding events at 2 years after percutaneous coronary intervention, ticagrelor monotherapy demonstrated a 6% risk reduction, compared with conventional 12-month DAPT in time-to-first-event analysis (hazard ratio, 0.94 [95% CI, 0.88-1.01]; log-rank P=0.10). In win ratio analysis, win ratio was 1.05 (95% CI, 0.97-1.13; P=0.20). Negative binomial regression and Andersen-Gill analyses which include repeated events showed statistically significant advantage for ticagrelor monotherapy (rate ratio, 0.92 [95% CI, 0.85-0.99; P=0.020] and hazard ratio, 0.92 [95% CI, 0.85-0.99; P=0.028], respectively), although in weighted composite end point analysis, the hazard ratio was 0.93 (95% CI, 0.84-1.04; log-rank P=0.22).

CONCLUSIONS

Statistical analyses considering repeated events or event severity showed that ticagrelor monotherapy consistently reduced ischemic and bleeding events by 5% to 8%, compared with conventional 1-year DAPT. Applying multiple statistical methods could emphasize the multiple facets of a trial and result in accurate and more appropriate analyses. Considering the recurrence of ischemic and bleeding events, ticagrelor monotherapy appeared to be beneficial after percutaneous coronary intervention. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT01813435.

Mortality After Repeat Revascularization Following PCI or CABG for Left Main Disease: The EXCEL Trial

OBJECTIVES

The aim of this study was to investigate the incidence and impact on mortality of repeat revascularization after index percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG) for left main coronary artery disease (LMCAD).

BACKGROUND

The impact on mortality of the need of repeat revascularization following PCI or CABG in patients with unprotected LMCAD is unknown.

METHODS

All patients with LMCAD and site-assessed low or intermediate SYNTAX (Synergy Between PCI With Taxus and Cardiac Surgery) scores randomized to PCI (n = 948) or CABG (n = 957) in the EXCEL (Evaluation of XIENCE Versus Coronary Artery Bypass Surgery for Effectiveness of Left Main Revascularization) trial were included. Repeat revascularization events were adjudicated by an independent clinical events committee. The effect of repeat revascularization on mortality through 3-year follow-up was examined in time-varying Cox regression models.

RESULTS

During 3-year follow-up, there were 346 repeat revascularization procedures among 185 patients. PCI was associated with higher rates of any repeat revascularization (12.9% vs. 7.6%; hazard ratio: 1.73; 95% confidence interval: 1.28 to 2.33; p = 0.0003). Need for repeat revascularization was independently associated with increased risk for 3-year all-cause mortality (adjusted hazard ratio: 2.05; 95% confidence interval: 1.13 to 3.70; p = 0.02) and cardiovascular mortality (adjusted hazard ratio: 4.22; 95% confidence interval: 2.10 to 8.48; p < 0.0001) consistently after both PCI and CABG (p_int = 0.85 for both endpoints). Although target vessel revascularization and target lesion revascularization were both associated with an increased risk for mortality, target vessel non-target lesion revascularization and non-target vessel revascularization were not.

CONCLUSIONS

In the EXCEL trial, repeat revascularization during follow-up was performed less frequently after CABG than PCI and was associated with increased mortality after both procedures. Reducing the need for repeat revascularization may further improve long-term survival after percutaneous or surgical treatment of LMCAD. (EXCEL Clinical Trial; NCT01205776).

Choosing primary endpoints for clinical trials of health care interventions

The purpose of late phase clinical trials is to generate evidence of sufficient validity and generalisability to be translated into practice and policy to improve health outcomes. It is therefore crucial that the chosen endpoints are meaningful to the clinicians, patients and policymakers that are the end-users of evidence generated by these trials. The choice of endpoints may be improved by understanding their characteristics and properties. This narrative review describes the evolution, range and relative strengths and weaknesses of endpoints used in late phase trials. It is intended to serve as a reference to assist those designing trials when choosing primary endpoint(s), and for the end-users charged with interpreting these trials to inform practice and policy.

Percutaneous Coronary Intervention vs Coronary Artery Bypass Grafting in Patients With Left Main Coronary Artery Stenosis: A Systematic Review and Meta-analysis

Importance

In patients with left main coronary artery (LMCA) stenosis, coronary artery bypass grafting (CABG) has been the standard therapy for several decades. However, some studies suggest that percutaneous coronary intervention (PCI) with drug-eluting stents may be an acceptable alternative.

Objective

To compare the long-term safety of PCI with drug-eluting stent vs CABG in patients with LMCA stenosis.

Data Sources

PubMed, Scopus, EMBASE, Web of Knowledge, and ScienceDirect databases were searched from December 18, 2001, to February 1, 2017. Inclusion criteria were randomized clinical trial, patients with LMCA stenosis, PCI vs CABG, exclusive use of drug-eluting stents, and clinical follow-up of 3 or more years.

Data Extraction and Synthesis

Trial-level hazard ratios (HRs) and 95% CIs were pooled by fixed-effect and random-effects models with inverse variance weighting. Time-to-event individual patient data for the primary end point were reconstructed. Sensitivity analyses according to drug-eluting stent generation and coronary artery disease complexity were performed.

Main Outcomes and Measures

The primary end point was a composite of all-cause death, myocardial infarction, or stroke at long-term follow-up. Secondary end points included repeat revascularization and a composite of all-cause death, myocardial infarction, stroke, or repeat revascularization at long-term follow-up.

Results

A total of 4 randomized clinical trials were pooled; 4394 patients were included in the analysis. Of these, 3371 (76.7%) were men; pooled mean age was 65.4 years. According to Grading of Recommendations, Assessment, Development and Evaluation, evidence quality with respect to the primary composite end point was high. Percutaneous coronary intervention and CABG were associated with a comparable risk of all-cause death, myocardial infarction, or stroke both by fixed-effect (HR, 1.06; 95% CI, 0.90-1.24; P = .48) and random-effects (HR, 1.06; 95% CI, 0.85-1.32; P = .60) analysis. Sensitivity analyses according to low to intermediate Synergy Between PCI With Taxus and Cardiac Surgery (SYNTAX) score (random-effects: HR, 1.02; 95% CI, 0.74-1.41; P = .89) and drug-eluting stent generation (first generation: HR, 0.90; 95% CI, 0.68-1.20; P = .49; second generation: HR, 1.19; 95% CI, 0.82-1.73; P = .36) were consistent. Kaplan-Meier curve reconstruction did not show significant variations over time between the techniques, with a 5-year incidence of all-cause death, myocardial infarction, or stroke of 18.3% (319 events) in patients treated with PCI and 16.9% (292 events) in patients treated with CABG. However, repeat revascularization after PCI was increased (HR, 1.70; 95% CI, 1.42-2.05; P < .001). Other individual secondary end points did not differ significantly between groups. Finally, pooled estimates of trials with LMCA stenosis tended overall to differ significantly from those of trials with multivessel coronary artery disease without left main LMCA stenosis.

Conclusions and Relevance

Percutaneous coronary intervention and CABG show comparable safety in patients with LMCA stenosis and low to intermediate-complexity coronary artery disease. However, repeat revascularization is more common after PCI.

New-generation drug-eluting stents for left main coronary artery disease according to the EXCEL trial enrollment criteria: Insights from the all-comers, international, multicenter DELTA-2 registry

BACKGROUND

Percutaneous coronary intervention (PCI) has been established as an alternative treatment option to coronary artery by-pass graft (CABG) surgery in patients with left main coronary artery disease (LMCAD). Whether the findings of randomized controlled trials are applicable to a real-world patient population is unclear.

METHODS

We compared the outcomes of PCI with new-generation DES in the all-comer, international, multicenter DELTA-2 registry retrospectively evaluating mid-term clinical outcomes with the historical CABG cohort enrolled in the DELTA-1 registry according to the EXCEL key inclusion or exclusion criteria. The primary endpoint was the composite of death, myocardial infarction, or stroke at the median time of follow-up time of 501 days. The consistency of the effect of DELTA-2 PCI versus DELTA-1 CABG according to the EXCEL enrollment criteria was tested using propensity score-adjusted Cox regression models.

RESULTS

Out of 3986 patients enrolled in the DELTA-2 PCI registry, 2418 were EXCEL candidates and 1568 were not EXCEL candidates. The occurrence of the primary endpoint was higher among non-EXCEL candidates compared with EXCEL candidates (15.4% vs. 6.9%; hazard ratio 2.52; 95% confidence interval 2.00-3.16; p < 0.001). Among 901 patients enrolled in the historical DELTA-1 CABG cohort, 471 were EXCEL candidates and 430 were not EXCEL candidates. When comparing the DELTA-2 PCI with the DELTA-1 CABG cohort, the occurrence of the primary endpoint was lower in the PCI group compared with the historical CABG cohort among EXCEL candidates (6.9% vs. 10.7%; adjusted hazard ratio: 0.65; 95% confidence interval: 0.45-0.92), while no significant difference was observed among non-EXCEL candidates (15.4% vs. 12.5%; adjusted hazard ratio: 0.94; 95% confidence interval: 0.67-1.33) with evidence of statistical interaction (adjusted interaction p-value = 0.002).

CONCLUSIONS

In a real-world population, PCI can be selected more favorably as an alternative to CABG in patients fulfilling the enrollment criteria of the EXCEL trial.

The DELTA 2 Registry: A Multicenter Registry Evaluating Percutaneous Coronary Intervention With New-Generation Drug-Eluting Stents in Patients With Obstructive Left Main Coronary Artery Disease

OBJECTIVES

The aim of this study was to evaluate clinical outcomes of unprotected left main coronary artery percutaneous coronary intervention (PCI) with new-generation drug-eluting stents in a "real world" population.

BACKGROUND

PCI of the unprotected left main coronary artery is currently recommended as an alternative to coronary artery bypass grafting (CABG) in selected patients.

METHODS

All consecutive patients with unprotected left main coronary artery stenosis treated by PCI with second-generation drug-eluting stents were analyzed in this international, all-comers, multicenter registry. The results were compared with those from the historical DELTA 1 (Drug Eluting Stent for Left Main Coronary Artery) CABG cohort using propensity score stratification. The primary endpoint was the composite of death, myocardial infarction (MI), or stroke at the median time of follow-up.

RESULTS

A total of 3,986 patients were included. The mean age was 69.6 ± 10.9 years, diabetes was present in 30.8%, and 21% of the patients presented with acute MI. The distal left main coronary artery was involved in 84.6% of the lesions. At a median of 501 days (≈17 months) of follow-up, the occurrence of the primary endpoint of death, MI, or cerebrovascular accident was lower in the PCI DELTA 2 group compared with the historical DELTA 1 CABG cohort (10.3% vs. 11.6%; adjusted hazard ratio: 0.73; 95% confidence interval: 0.55 to 0.98; p = 0.03). Of note, an advantage of PCI was observed with respect to cerebrovascular accident (0.8% vs. 2.0%; adjusted hazard ratio: 0.37; 95% confidence interval: 0.16 to 0.86; p = 0.02), while an advantage of CABG was observed with respect to target vessel revascularization (14.2% vs. 2.9%; adjusted hazard ratio: 3.32; 95% confidence interval: 2.12 to 5.18; p < 0.0001).

CONCLUSIONS

After a median follow-up period of 17 months, PCI with new-generation drug-eluting stents was associated with an overall low rate of the composite endpoint of death, MI, or cerebrovascular accident.

Long-term outcomes following left main bifurcation stenting in Indian population-Analysis based on SYNTAX I and II scores

Background

Syntax 1 and recently Syntax 2 (SS2) scores are validated risk prediction models in coronary disease.

Objectives

To find out the long term outcomes following stenting for unprotected left main bifurcation disease (LMD) and to validate and compare the performance of the SYNTAX scores 1 and 2 (SS1 and SS2 PCI) for predicting major adverse cardiac events (MACE) in Indian population.

Methods

Single-center, retrospective, observational study involving patients who underwent percutaneous coronary intervention (PCI) with at least one stent implanted for the LMD. Discrimination and calibration models were assessed by ROC curve and the Hosmer-Lemeshow test.

Results

Data of 103 patients were analyzed. The mean SS1 and SS2 scores were 27.9 and 30.7 and MACE was 16.5% at 4 years. The target lesion revascularization (TLR) rate at 4 years was 11(10.7%). There were 4 deaths (3.8%). The mean left ventricular ejection fraction (LVEF) was the only variable in SS2, which predicted cardiac events. ROC curve analysis showed both models to be accurate in predicting TLR and mortality following LM PCI. SS2 score showed a better risk prediction than SSI with AUC for TLR (SSI 0.560 and SS2PCI 0.625) and AUC for mortality (SS1 0.674 and SS2PCI 0.833). Hosmer-Lemeshow test validated the accuracy of both the risk models in predicting the events.

Conclusions

Both risk models were applicable for Indian patients. The SS2 score was a better predictor for mortality and TLR. In the SS2 score, the LVEF was the most useful predictor of events after LM PCI.

Percutaneous coronary intervention versus coronary artery bypass grafting: where are we after NOBLE and EXCEL?

PURPOSE OF REVIEW

The publication of the NOBLE and EXCEL trials, with seemingly conflicting results, brought into question whether percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG) is better for low-risk patients with left main coronary artery stenosis (LMCAS). This review appraises the methods and results of NOBLE and EXCEL, contextualizes them within the literature, and determines how they may affect clinical practice.

RECENT FINDINGS

We appraised the trials and describe differences in methodology and results. NOBLE recruited primarily isolated LMCAS, and found that CABG was superior to PCI. EXCEL's population included patients LMCAS in the context of multivessel CAD, and found PCI and CABG were comparable. Both trials enrolled young patients with few comorbidities, and there was more protocol-mandated consistency in the procedural techniques and medical therapy of patients receiving PCI.

SUMMARY

The generalizability of these trials is limited by the use of young, healthy patients at highly skilled centres that rarely reflect typical clinical practice. If these studies are to maintain relevance, trialists must address the lack of protocolization of surgical interventions and inconsistent medical therapies. Unfortunately, the limitations of NOBLE and EXCEL mean that we are no closer to answering the question of what is the optimal treatment for patients with LMCAS.

The Current State of Left Main Percutaneous Coronary Intervention

PURPOSE OF REVIEW

While coronary artery bypass grafting (CABG) remains the standard of care, advances in stenting technology and procedural technique are changing the role of percutaneous coronary intervention (PCI) in the treatment of severe left main coronary artery (LMCA) disease. We review contemporary evidence comparing PCI and CABG for the treatment of severe LMCA disease, discuss optimal techniques during left main PCI, and provide guidance on studied revascularization strategies within specific patient subgroups.

RECENT FINDINGS

Results from randomized control trials of patients treated with PCI or CABG for severe LMCA disease demonstrate comparable short- and mid-term rates of death, myocardial infarction (MI), and stroke, but increased rates of repeat or target-vessel revascularization after PCI. Though extended follow-up data has suggested lower long-term rates of MI and stroke in patients with severe LMCA disease treated with CABG, results from patients undergoing PCI with second-generation drug-eluting stents (DES) demonstrate non-inferiority in these outcomes. These findings are generalizable to patients with severe LMCA disease having low to intermediate anatomic complexity. Intravascular ultrasound and double kissing (DK) crush stenting also reduce adverse event rates among patients undergoing left main PCI and improve long-term outcomes. In patients with severe LMCA disease having low to intermediate anatomic complexity, both CABG and PCI with second-generation DES are effective methods of revascularization with comparable long-term rates of death, MI, and stroke. The roles of multi-vessel coronary artery disease and anatomic complexity on long-term outcomes after CABG or PCI for severe LMCA disease remain under investigation.

Composite End Points in Clinical Research

Advances in cardiovascular medicine fueled by innovative clinical trials have dramatically improved the lives of patients worldwide. Commensurate with this progress has been a decline in morbid and mortal events. Accordingly, an increased propensity to collate patient outcomes in clinical trials has emerged that combines death and nonfatal complications into a single composite event. Despite the acknowledged benefits in trial efficiency from such an approach, this method assumes uniform directionality of each component, does not distinguish the relative clinical significance of each, and counts only the first occurrence of any event in the final tally within a conventional time to first event analysis. In this article, we evaluate the criticisms that have been leveled at this approach and provide an overview of recently published phase III cardiovascular trials using primary composite end points. We then explore what to anticipate from the large cohort of as-yet unpublished clinical trials in this arena. Last, we propose a variety of novel approaches that use composite end points and suggest a path forward to enhancing their use in future clinical trials.