Improving the Design of Future PCI Trials for Stable Coronary Artery Disease: JACC State-of-the-Art Review

STICH3C: Rationale and Study Protocol

BACKGROUND

Coronary artery bypass grafting (CABG) is the recommended mode of revascularization in patients with ischemic left ventricular dysfunction (iLVSD) and multivessel disease. However, contemporary percutaneous coronary intervention (PCI) outcomes have improved with the integration of novel technologies and refinement of revascularization strategies, and PCI is often used in clinical practice in this population. There is a lack of evidence from randomized trials comparing contemporary state-of-the-art PCI versus CABG for the treatment of iLVSD and multivessel disease. This was the impetus for the STICH3C trial (Canadian CABG or PCI in Patients With Ischemic Cardiomyopathy), described here.

METHODS

The STICH3C trial is a prospective, unblinded, international, multicenter trial with an expected sample size of 754 participants from ≈45 centers. Patients with multivessel/left main coronary artery disease and iLVSD with left ventricular ejection fraction ≤40% considered by the local Heart Team appropriate for and amenable to revascularization by both modes of revascularization will be randomized in a 1:1 ratio to state-of-the-art PCI or CABG.

RESULTS

The primary end point is the composite of death from any cause, stroke, spontaneous myocardial infarction, urgent repeat revascularization, or heart failure readmission, summarized as a time-to-event outcome. The key hierarchical end point is time to death and frequency of hospitalizations for heart failure. The key safety outcome is a composite of major adverse events. Disease-specific quality-of-life and health economics measures will be compared between groups. Participants will be followed for a median of 5 years, with a minimum follow-up of 4 years.

CONCLUSIONS

STICH3C will directly inform patients, clinicians, and international practice guidelines about the efficacy and safety of CABG versus PCI in patients with iLVSD. The results will provide novel and broad evidence, including clinical events, health status, and economic assessments, to guide care for patients with iLVSD and severe coronary artery disease.

REGISTRATION

URL: https://clinicaltrials.gov/; Unique identifier: NCT05427370.

Long-term mortality in asymptomatic patients with stable ischemic heart disease undergoing percutaneous coronary intervention

OBJECTIVES

Patients with stable ischemic heart disease (SIHD) may present with a variety of symptoms including typical angina, angina equivalents such as dyspnea or no symptoms. We sought to determine whether symptom status affects periprocedural safety and long-term mortality in patients undergoing PCI.

METHODS

Prospectively enrolled consecutive patients undergoing PCI for SIHD at six hospitals in Australia between 2005 to 2018 as part of the Melbourne Interventional Group registry. Symptom status was recorded at the time of PCI and patients undergoing staged PCI were excluded.

RESULTS

Overall, 11,730 patients with SIHD were followed up for a median period of 5 years (maximum 14.0 years, interquartile range 2.2-9.0 years) with 1,317 (11.2%) being asymptomatic. Asymptomatic patients were older, and more likely to be male, have triple-vessel disease, with multiple comorbidities including renal failure, diabetes and heart failure (all P < .01). These patients had significantly higher rates of periprocedural complications and major adverse cardiovascular events at 30-days. Long-term mortality was significantly higher in asymptomatic patients (27.2% vs 18.0%, P < .001). On cox regression for long-term mortality, after adjustment for more important clinical variables, asymptomatic status was an independent predictor (Hazard ratio (HR) 1.39 95% CI 1.16-1.66, P < .001).

CONCLUSIONS

In a real-world cohort of patients undergoing revascularization for SIHD, absence of symptoms was associated with higher rates of periprocedural complications and, after adjustment for more important clinical variables, was an independent predictor of long-term mortality. As the primary goal of revascularization in SIHD remains angina relief, the appropriateness of PCI in the absence of symptoms warrants justification.

A Call to Action for New Global Approaches to Cardiovascular Disease Drug Solutions

While we continue to wrestle with the immense challenge of implementing equitable access to established evidence-based treatments, substantial gaps remain in our pharmacotherapy armament for common forms of cardiovascular disease including coronary and peripheral arterial disease, heart failure, hypertension, and arrhythmia. We need to continue to invest in the development of new approaches for the discovery, rigorous assessment, and implementation of new therapies. Currently, the time and cost to progress from lead compound/product identification to the clinic, and the success rate in getting there reduces the incentive for industry to invest, despite the enormous burden of disease and potential size of market. There are tremendous opportunities with improved phenotyping of patients currently batched together in syndromic "buckets." Use of advanced imaging and molecular markers may allow stratification of patients in a manner more aligned to biological mechanisms that can, in turn, be targeted by specific approaches developed using high-throughput molecular technologies. Unbiased "omic" approaches enhance the possibility of discovering completely new mechanisms in such groups. Furthermore, advances in drug discovery platforms, and models to study efficacy and toxicity more relevant to the human disease, are valuable. Re-imagining the relationships among discovery, translation, evaluation, and implementation will help reverse the trend away from investment in the cardiovascular space, establishing innovative platforms and approaches across the full spectrum of therapeutic development.

Posttranslational Modifications: Emerging Prospects for Cardiac Regeneration Therapy

Heart failure (HF) following ischemic heart disease (IHD) remains a hard nut to crack and a leading cause of death worldwide. Cardiac regeneration aims to promote cardiomyocyte (CM) proliferation by transitioning the cell cycle state of CMs from arrest to re-entry. Protein posttranslational modifications (PTMs) have recently attracted extensive attention in the field of cardiac regeneration due to their reversibility and effects on the stability, activity, and subcellular localization of target proteins. The balance of PTMs is disrupted when neonatal CMs withdraw from the cell cycle, resulting in significant dysfunction of downstream substrate protein localization, expression, and activity, ultimately limiting the maintenance of cardiac regeneration ability. In this review, we summarize recent research concerning the role of PTMs in cardiac regeneration, while focusing on phosphorylation, acetylation, ubiquitination, glycosylation, methylation, and neddylation, and the effects of these modifications on CM proliferation, which may provide potential targets for future treatments for IHD.

A call to action for new global approaches to cardiovascular disease drug solutions

Whilst we continue to wrestle with the immense challenge of implementing equitable access to established evidence-based treatments, substantial gaps remain in our pharmacotherapy armament for common forms of cardiovascular disease including coronary and peripheral arterial disease, heart failure, hypertension, and arrhythmia. We need to continue to invest in the development of new approaches for the discovery, rigorous assessment, and implementation of new therapies. Currently, the time and cost to progress from lead compound/product identification to the clinic, and the success rate in getting there reduces the incentive for industry to invest, despite the enormous burden of disease and potential size of market. There are tremendous opportunities with improved phenotyping of patients currently batched together in syndromic 'buckets'. Use of advanced imaging and molecular markers may allow stratification of patients in a manner more aligned to biological mechanisms that can, in turn, be targeted by specific approaches developed using high-throughput molecular technologies. Unbiased 'omic' approaches enhance the possibility of discovering completely new mechanisms in such groups. Furthermore, advances in drug discovery platforms, and models to study efficacy and toxicity more relevant to the human disease, are valuable. Re-imagining the relationships among discovery, translation, evaluation, and implementation will help reverse the trend away from investment in the cardiovascular space, establishing innovative platforms and approaches across the full spectrum of therapeutic development.

Myocardial Ischemia in the Management of Chronic Coronary Artery Disease: Past and Present

For many years, stress-induced myocardial ischemia has been considered important in the management of chronic coronary artery disease. Early evidence focused on the exercise ECG and the Duke treadmill score. In the 1970s, randomized clinical trials, which compared coronary artery bypass surgery to medical therapy, enrolled patients who were very different from contemporary practice and had inconsistent results. Surgery appeared to be of greatest benefit in high-risk patients defined by anatomy (such as left main disease) or stress-induced ischemia. However, randomized clinical trials of revascularization versus contemporary medical therapy over the past 20 years have been surprisingly negative. Nuclear cardiology substudies from these trials reported inconsistent results. Two observational studies from a single-center provided the best evidence for the use of stress-induced ischemia to identify patients who were most likely to benefit from revascularization. The recently completed ISCHEMIA trial (International Study of Comparative Health Effectiveness With Medical and Invasive Approaches) was designed to test the hypothesis that revascularization would improve outcomes in patients with moderate-severe ischemia on stress testing. Unfortunately, 14.2% of the randomized patients had either mild or no ischemia on core lab review. Nearly one-quarter of the patients were randomized on the basis of an exercise ECG without imaging. The negative results of the trial reflect the long-term population decline in coronary artery disease and abnormal stress tests, as well as improvements in patient outcome due to optimal medical therapy. Topics requiring further research are presented. The implications of the trial for the use of both stress imaging and coronary computed tomography angiography in clinical practice are examined.