External applicability of the ISCHEMIA trial: an analysis of a prospective, nationwide registry of patients with stable coronary artery disease

Deferred Versus Performed Revascularization for Left Main Coronary Disease With Hemodynamic Significance

BACKGROUND

The majority of randomized controlled trials of revascularization decision-making excludes left main coronary artery disease (LMD). Therefore, contemporary clinical outcomes of patients with stable coronary artery disease and LMD with proven ischemia remain poorly understood. The aim of this study was to assess the long-term clinical outcomes of physiologically significant LMD according to the treatment strategies of revascularization versus revascularization deferral.

METHODS

In this international multicenter registry of stable LMD interrogated with the instantaneous wave-free ratio, patients with physiologically significant ischemia (instantaneous wave-free ratio ≤0.89) were analyzed according to the coronary revascularization (n=151) versus revascularization deferral (n=74). Propensity score matching was performed to adjust for baseline clinical characteristics. The primary end point was a composite of death, nonfatal myocardial infarction, and ischemia-driven target lesion revascularization of left main stem. The secondary end points were as follows: cardiac death or spontaneous LMD-related myocardial infarction; and ischemia-driven target lesion revascularization of left main stem.

RESULTS

At a median follow-up period of 2.8 years, the primary end point occurred in 11 patients (14.9%) in the revascularized group and 21 patients (28.4%) in the deferred group (hazard ratio, 0.42 [95% CI, 0.20-0.89]; P=0.023). For the secondary end points, cardiac death or LMD-related myocardial infarction occurred significantly less frequently in the revascularized group (0.0% versus 8.1%; P=0.004). The rate of ischemia-driven target lesion revascularization of left main stem was also significantly lower in the revascularized group (5.4% versus 17.6%; hazard ratio, 0.20 [95% CI, 0.056-0.70]; P=0.012).

CONCLUSIONS

In patients who underwent revascularization for stable coronary artery disease and physiologically significant LMD determined by instantaneous wave-free ratio, the long-term clinical outcomes were significantly improved as compared with those in whom revascularization was deferred.

Health Status and Clinical Outcomes in Older Adults With Chronic Coronary Disease: The ISCHEMIA Trial

BACKGROUND

Whether initial invasive management in older vs younger adults with chronic coronary disease and moderate or severe ischemia improves health status or clinical outcomes is unknown.

OBJECTIVES

The goal of this study was to examine the impact of age on health status and clinical outcomes with invasive vs conservative management in the ISCHEMIA (International Study of Comparative Health Effectiveness with Medical and Invasive Approaches) trial.

METHODS

One-year angina-specific health status was assessed with the 7-item Seattle Angina Questionnaire (SAQ) (score range 0-100; higher scores indicate better health status). Cox proportional hazards models estimated the treatment effect of invasive vs conservative management as a function of age on the composite clinical outcome of cardiovascular death, myocardial infarction, or hospitalization for resuscitated cardiac arrest, unstable angina, or heart failure.

RESULTS

Among 4,617 participants, 2,239 (48.5%) were aged <65 years, 1,713 (37.1%) were aged 65 to 74 years, and 665 (14.4%) were aged ≥75 years. Baseline SAQ summary scores were lower in participants aged <65 years. Fully adjusted differences in 1-year SAQ summary scores (invasive minus conservative) were 4.90 (95% CI: 3.56-6.24) at age 55 years, 3.48 (95% CI: 2.40-4.57) at age 65 years, and 2.13 (95% CI: 0.75-3.51) at age 75 years (Pinteraction = 0.008). Improvement in SAQ Angina Frequency was less dependent on age (Pinteraction = 0.08). There were no age differences between invasive vs conservative management on the composite clinical outcome (Pinteraction = 0.29).

CONCLUSIONS

Older patients with chronic coronary disease and moderate or severe ischemia had consistent improvement in angina frequency but less improvement in angina-related health status with invasive management compared with younger patients. Invasive management was not associated with improved clinical outcomes in older or younger patients. (International Study of Comparative Health Effectiveness with Medical and Invasive Approaches [ISCHEMIA]; NCT01471522).

Clinical application of results of the ISCHEMIA trial

More than a decade after the Clinical Outcomes Utilising Revascularization and Aggressive Drug Evaluation (COURAGE) trial, International Study of Comparative Health Effectiveness With Medical And Invasive Approaches (ISCHEMIA) is the second large clinical trial to challenge the concept of revascularization in chronic coronary syndromes whilst addressing some of the shortfalls of its predecessor.

Trends and Real-World Safety of Patients Undergoing Percutaneous Coronary Intervention for Symptomatic Stable Ischaemic Heart Disease in Australia

BACKGROUND

Percutaneous coronary intervention (PCI) in stable ischaemic heart disease (SIHD) has not been shown to improve prognosis but can alleviate symptoms and improve quality of life. Appropriately selected patients with symptoms refractory to medical therapy therefore stand to benefit, provided safety is proven.

METHODS

Consecutive patients undergoing PCI for SIHD between 2005-2018 in a prospective registry were included. Yearly comparisons evaluated trends, and a sub-analysis was performed comparing proximal left anterior descending artery (prox-LAD) to other-than-proximal LAD (non-pLAD) PCI. Outcomes included peri-procedural characteristics, in-hospital and 30-day event rates including MACE, and 5-year National Death Index (NDI) linked mortality.

RESULTS

There were 9,421 procedures included. Over time, patients were increasingly co-morbid and had higher rates of AHA/ACC class B2/C lesions, ostial stenoses, bifurcation lesions, and chronic total occlusions (all p-for-trend ≤0.001). Over 14 years, major bleeding reduced (1.05% in 2005/06 vs 0.29% in 2017/18, p-for-trend <0.001), while other in-hospital and 30-day event rates were stably low. There were only seven (0.07%) in hospital deaths and 5-year mortality was 10.3%. No differences were found in outcomes between patients who underwent prox-LAD compared to non-pLAD PCI. Major independent predictors of NDI linked all-cause mortality included an eGFR <30 mL/min/1.73 m² (HR 4.06, 95% CI 3.26-5.06), chronic obstructive pulmonary disease (COPD) (HR 2.25, 95% CI 1.89-2.67) and LVEF <30% (HR 2.13, 95% CI 1.57-2.89).

CONCLUSIONS

Although patient and procedural complexity increased over time, a high degree of procedural success and safety was maintained, including in those undergoing prox-LAD PCI. These real-world data can enhance shared decision making discussions regarding whether PCI should be pursued in patients with symptomatic SIHD refractory to medical therapy.

Ischemia Trial: Does the Cardiology Community Need to Pivot or Continue Current Practices?

PURPOSE OF REVIEW

For decades, the standard of care for stable ischemic heart disease (SIHD) has been an ischemia-centric approach based on largely observational data suggesting a survival benefit of revascularization in patients with moderate-or-severe ischemia. In this article, we will objectively review the evolution of the ischemia paradigm, the trial evidence comparing revascularization to medical therapy in SIHD, and what contemporary practice should be in 2022.

RECENT FINDINGS

Randomized trials, including COURAGE and, most recently, the ISCHEMIA trial, have shown no reduction in "hard outcomes" like death and myocardial infarction (MI) in SIHD compared to medical therapy. The trial excluded high-risk patients with left main disease, low ejection fraction (EF) < 35%, and severe unacceptable angina. Irrespective of the severity of ischemia and the extent of coronary artery disease (CAD), revascularization did not offer any prognostic advantage over medical therapy. On the other hand, there was a durable improvement in symptoms. While there are many caveats to the ISCHEMIA trial, the overall strengths of the trial outweigh these limitations. The findings of ISCHEMIA are consistent with previous trials. It is time for the cardiology community to pivot towards medical therapy as the initial step for most patients with SIHD. Physicians should have the "COURAGE" to embrace "ISCHEMIA" and be comfortable with treating ischemia medically.

Does the ISCHEMIA Trial Apply to My Patients?

PURPOSE OF REVIEW

The ISCHEMIA trial demonstrated no difference in myocardial infarction or death in patients with stable coronary disease and moderate or large ischemia territory treated either with invasive revascularization or optimal medical therapy. Whether the findings of the randomized control trial relates to real-world outcomes is uncertain.

RECENT FINDINGS

Contemporary guideline-directed medical therapy has had a significant impact on the prognosis of coronary artery disease. Various observational data appear to indicate limited generalizability of the ISCHEMIA trial in different populations. Further studies are warranted to evaluate the optimal modality of therapy in patients with stable coronary disease and moderate or severe ischemia. The applicability of ISCHEMIA and ISCHEMIA-CKD trials still requires further validation.

Comparison of Patients Undergoing Percutaneous Coronary Intervention in Contemporary U.S. Practice With ISCHEMIA Trial Population

OBJECTIVES

The study sought to assess the proportion of patients in modern U.S. interventional practice that fulfilled criteria for enrollment in the ISCHEMIA (International Study of Comparative Health Effectiveness With Medical and Invasive Approaches) trial.

BACKGROUND

The ISCHEMIA trial, which enrolled patients with stable ischemic heart disease (SIHD), showed that revascularization improved angina symptoms with little effect on death or myocardial infarction.

METHODS

A cross-sectional analysis of the National Cardiovascular Data Registry CathPCI Registry (v5.0), including 1,662 hospitals, was performed. Patients undergoing percutaneous coronary intervention (PCI) for SIHD in routine clinical practice meeting ISCHEMIA trial inclusion criteria and those that did not were evaluated.

RESULTS

During the study period, 388,212 patients underwent PCI for SIHD, comprising 41.88% of all patients undergoing PCI during the study period. Of these, 125,302 (32.28%; 13.52% of all patients undergoing PCI) met criteria for enrollment in the ISCHEMIA trial. Among SIHD patients that did not meet criteria, 71,852 (18.51%) had SIHD with high-risk features (35.2% left main disease, 43.7% left ventricular systolic dysfunction, 16.8% end-stage renal disease), 67,159 (17.3%) had SIHD with negative or low-risk functional testing, and 123,899 (31.92%) either had no stress testing or did not have ischemic burden reported. At the median hospital, 32.1% (interquartile range: 23.5%-40.6%) of SIHD patients met criteria for enrollment in the ISCHEMIA trial, with these patients experiencing lower unadjusted in-hospital mortality rate than comparator groups who met exclusion criteria for the trial (0.11%) (P < 0.01 for all comparisons).

CONCLUSIONS

Among contemporary U.S. patients undergoing PCI for SIHD, 32.28% clearly met enrollment criteria for the ISCHEMIA trial. There was significant variation among individual centers in the proportion of SIHD patients meeting criteria for the ISCHEMIA trial.

Stent visualization methods to guide percutaneous coronary interventions and assess long-term patency

Evaluation of acute percutaneous coronary intervention (PCI) results and long-term follow-up remains challenging with ongoing stent designs. Several imaging tools have been developed to assess native vessel atherosclerosis and stent expansion, improving overall PCI results and reducing adverse cardiac events. Quantitative coronary analysis has played a crucial role in quantifying the extent of coronary artery disease and stent results. Digital stent enhancement methods have been well validated and improved stent strut visualization. Intravascular imaging remains the gold standard in PCI guidance but adds costs and time to the procedure. With a recent shift towards non-invasive imaging assessment and coronary computed tomography angiography imaging have shown promising results. We hereby review novel stent visualization techniques used to guide PCI and assess stent patency in the modern PCI era.

Non-invasive Imaging in Patients With Chronic Total Occlusions of the Coronary Arteries-What Does the Interventionalist Need for Success?

Chronic total occlusion (CTO) of coronary arteries is a common finding in patients with known or suspected coronary artery disease (CAD). Although tremendous advances have been made in the interventional treatment of CTOs over the past decade, correct patient selection remains an important parameter for achieving optimal results. Non-invasive imaging can make a valuable contribution. Ischemia and viability, two major factors in this regard, can be displayed using echocardiography, single-photon emission tomography, positron emission tomography, computed tomography, and cardiac magnetic resonance imaging. Each has its own strengths and weaknesses. Although most have been studied in patients with CAD in general, there is an increasing number of studies with positive preselectional factors for patients with CTOs. The aim of this review is to provide a structured overview of the current state of pre-interventional imaging for CTOs.

Role of Concomitant Coronary Artery Bypass Grafting in Valve Surgery for Infective Endocarditis

BACKGROUND

It is current practice to perform concomitant coronary artery bypass grafting (CABG) in patients with infective endocarditis (IE) who have relevant coronary artery disease (CAD). However, CABG may add complexity to the operation. We aimed to investigate the impact of concomitant CABG on perioperative outcomes in patients undergoing surgery for IE.

METHODS

We retrospectively used data of surgically treated IE patients between 1994 and 2018 in six German cardiac surgery centers. We performed inverse probability weighting (IPW), multivariable adjustment, chi-square analysis, and Kaplan-Meier survival estimates.

RESULTS

CAD was reported in 1242/4917 (25%) patients. Among them, 527 received concomitant CABG. After adjustment for basal characteristics between CABG and no-CABG patients using IPW, concomitant CABG was associated with higher postoperative stroke (26% vs. 21%, p = 0.003) and a trend towards higher postoperative hemodialysis (29% vs. 25%, p = 0.052). Thirty-day mortality was similar in both groups (24% vs. 23%, p = 0.370). Multivariate Cox regression analysis after IPW showed that CABG was not associated with better long-term survival (HR: 1.00, 95% CI: 0.82-1.23, p = 0.998).

CONCLUSION

In endocarditis patients with CAD, adding CABG to valve surgery may be associated with a higher likelihood of postoperative stroke without adding long-term survival benefits. Therefore, in the absence of critical CAD, concomitant CABG may be omitted without impacting outcome. The results are limited due to a lack of data on the severity of CAD, and therefore there is a need for a randomized trial.

What Is the Clinical Impact of Stress CMR After the ISCHEMIA Trial?

After progressively receding for decades, cardiovascular mortality due to coronary artery disease has recently increased, and the associated healthcare costs are projected to double by 2030. While the 2019 European Society of Cardiology guidelines for chronic coronary syndromes recommend non-invasive cardiac imaging for patients with suspected coronary artery disease, the impact of non-invasive imaging strategies to guide initial coronary revascularization and improve long-term outcomes is still under debate. Recently, the ISCHEMIA trial has highlighted the fundamental role of optimized medical therapy and the lack of overall benefit of early invasive strategies at a median follow-up of 3.2 years. However, sub-group analyses excluding procedural infarctions with longer follow-ups of up to 5 years have suggested that patients undergoing revascularization had better outcomes than those receiving medical therapy alone. A recent sub-study of ISCHEMIA in patients with heart failure or reduced left ventricular ejection fraction (LVEF <45%) indicated that revascularization improved clinical outcomes compared to medical therapy alone. Furthermore, other large observational studies have suggested a favorable prognostic impact of coronary revascularization in patients with severe inducible ischemia assessed by stress cardiovascular magnetic resonance (CMR). Indeed, some data suggest that stress CMR-guided revascularization assessing the extent of the ischemia could be useful in identifying patients who would most benefit from invasive procedures such as myocardial revascularization. Interestingly, the MR-INFORM trial has recently shown that a first-line stress CMR-based non-invasive assessment was non-inferior in terms of outcomes, with a lower incidence of coronary revascularization compared to an initial invasive approach guided by fractional flow reserve in patients with stable angina. In the present review, we will discuss the current state-of-the-art data on the prognostic value of stress CMR assessment of myocardial ischemia in light of the ISCHEMIA trial results, highlighting meaningful sub-analyses, and still unanswered opportunities of this pivotal study. We will also review the available evidence for the potential clinical application of quantifying the extent of ischemia to stratify cardiovascular risk and to best guide invasive and non-invasive treatment strategies.

Revascularization decisions in patients with chronic coronary syndromes: Results of the second International Survey on Interventional Strategy (ISIS-2)

BACKGROUND

In chronic coronary syndromes, guidelines mandate invasive functional guidance of revascularization whenever non-invasive proof of ischemia is missing. ISIS-2 survey aimed to evaluate how the adoption of guideline recommendation on ischemia-guided revascularization has evolved over the last 5-7 years.

METHODS

In ISIS-2 participants assessed five complete angiograms, presenting only intermediate stenoses without information on non-invasive pre-testing. Fractional flow reserve was known for each stenosis, but remained undisclosed. Participants could determine stenosis significance either by angiography or by requesting an adjunctive invasive diagnostic method (intravascular imaging or functional tests). Primary endpoint was the rate of requesting adjunctive functional assessment. Secondary endpoints were the rate of concordance between angiography-based decisions and know functional severity. ISIS-2 utilized the same web-based platform as ISIS-1 in 2013. (NCT04001452).

RESULTS

334 participants performed 2059 lesion evaluations: 1202 (59%) decisions were based solely on angiography without expressed need for further evaluation. These decisions were discordant with known functional significance in 39%, mainly with potential of overtreatment. Participants requested invasive functional assessment in 643 (31%) and intravascular imaging in 214 (10%) cases. Compared to ISIS-1 the rate of purely angiography-based decisions has decreased (59% vs 66%; p < 0.001), while invasive functional tests were more frequently requested (31% vs 25%; p < 0.001).

CONCLUSIONS

ISIS-2 suggests an evolving pattern in the intention to integrate invasive coronary physiology into the revascularization decisions. However, the disconnect between recommendations and current thinking is still dominant.

Implementation of a Myocardial Perfusion Imaging Risk Algorithm to Inform Appropriate Downstream Invasive Testing and Treatment

BACKGROUND

To risk stratify patients undergoing single-photon emission computed tomography myocardial perfusion imaging (SPECT-MPI) in accordance with appropriate use criteria for referral to coronary angiography, we developed a risk classification algorithm incorporating appropriate use criteria-defined risk features. We evaluated the association between this algorithm with downstream angiography, revascularization, and all-cause mortality.

METHODS

We studied consecutive patients who underwent SPECT-MPI from January 1, 2015, to December 31, 2017, and assigned a scan risk of low, intermediate, high, or indeterminate. With this stratification, we assessed referral for angiography and revascularization within 3 months of SPECT-MPI and intermediate-term mortality.

RESULTS

Among 12 799 patients, the mean age was 66 years, and a majority were men (56.8%). Most patients were low risk (83.6%) followed by intermediate (9.9%) and high risk (5.2%). Compared with low-risk patients, intermediate- and high-risk patients were more frequently referred for angiography (14.8% and 13.6% versus 2.0%; P<0.001) and revascularization (7.7% and 6.8% versus 0.7%; P<0.001). In 1008 propensity-matched patients, scan risk was independently associated with angiography after adjustment for ischemia, scar, or stress ejection fraction. At a mean follow-up of 2.3 years, mortality was higher with increased scan risk (high, 10.4%; intermediate, 7.1%; low, 4.1%; P<0.001). Compared with low scan risk, intermediate (hazard ratio, 1.37 [95% CI, 1.09-1.72]; P=0.008) and high scan risk (hazard ratio, 1.98 [95% CI, 1.53-2.56]; P<0.001) were associated with mortality in multivariable analysis. Similar findings were observed for those undergoing pharmacological and exercise SPECT-MPI with comparatively worse prognosis among pharmacological patients.

CONCLUSIONS

This appropriate use criteria-derived risk classification algorithm for SPECT-MPI guided referral for coronary angiography and revascularization and was significantly associated with mortality. This algorithm may serve as an important tool to reaffirm appropriate use criteria and direct management of patients with stable ischemic heart disease undergoing stress testing.

Clinical implications and debates on the ISCHEMIA trial

The ISCHEMIA was eagerly awaited study in the field of ischemic heart disease. Following the presentation and publication of ISCHEMIA, multiple opinions and viewpoints get complicated. The ongoing debates have been including the relevance of coronary revascularization, non-invasive diagnostic methods, and invasive ischemic testing in patients with stable ischemic heart disease (SIHD). Prior to ISCHEMIA, observational studies indicated the potential of coronary revascularization for improving clinical outcomes, while the randomized COURAGE trial did not support the plausible concept. Although the FAME 2 trial implied the superiority of percutaneous coronary intervention over medical therapy alone, the clinical relevance of coronary revascularization to improve outcomes and quality of life has been questioned. As a consequence, the ISCHEMIA trial did not demonstrate clear benefits in reducing clinical events but showed antianginal effects of revascularization. This landmark trial also suggested the difficulties of non-invasive ischemia testing rather than computed tomography angiography. Despite the complex results, the ISCHEMIA trial may simplify the clinical indications of coronary revascularization in patients with SIHD. Future publications from the ISCHEMIA trial and debates on the results will sharpen our thinking and understanding.