Impact of ischaemia and scar on the therapeutic benefit derived from myocardial revascularization vs. medical therapy among patients undergoing stress-rest myocardial perfusion scintigraphy

DIagnostic accuracy oF electrocardiogram for acute coronary OCClUsion resuLTing in myocardial infarction (DIFOCCULT Study)

Background

Although ST-segment elevation (STE) has been used synonymously with acute coronary occlusion (ACO), current STE criteria miss nearly one-third of ACO and result in a substantial amount of false catheterization laboratory activations. As many other electrocardiographic (ECG) findings can reliably indicate ACO, we sought whether a new ACO/non-ACO myocardial infarction (MI) paradigm would result in better identification of the patients who need acute reperfusion therapy.

Methods

A total of 3000 patients were enrolled in STEMI, non-STEMI and control groups. All ECGs were reviewed by two cardiologists, blinded to any outcomes, for the current STEMI criteria and other subtle signs. A combined ACO endpoint was composed of peak troponin level, troponin rise within the first 24 h and angiographic appearance. The dead or alive status was checked from hospital records and from the electronic national database.

Results

In non-STEMI group, 28.2% of the patients were re-classified by the ECG reviewers as having ACO. This subgroup had a higher frequency of ACO, myocardial damage, and both in-hospital and long-term mortality compared to non-STEMI group. A prospective ACOMI/non-ACOMI approach to the ECG had superior diagnostic accuracy compared to the STE/non-STEMI approach in the prediction of ACO and long-term mortality. In Cox-regression analysis early intervention in patients with non-ACO-predicting ECGs was associated with a higher long-term mortality.

Conclusions

We believe that it is time for a new paradigm shift from the STEMI/non-STEMI to the ACOMI/non-ACOMI in the acute management of MI. (DIFOCCULT study; ClinicalTrials.gov number, NCT04022668.).

Coronary Flow Capacity to Identify Stenosis Associated With Coronary Flow Improvement After Revascularization: A Combined Analysis From DEFINE FLOW and IDEAL

Background Coronary flow capacity (CFC), which is a categorical assessment based on the combination of hyperemic coronary flow and coronary flow reserve (CFR), has been introduced as a comprehensive assessment of the coronary circulation to overcome the limitations of CFR alone. The aim of this study was to quantify coronary flow changes after percutaneous coronary intervention in relation to the classification of CFC and the current physiological cutoff values of fractional flow reserve, instantaneous wave-free ratio, and CFR. Methods and Results Using the combined data set from DEFINE FLOW (Distal Evaluation of Functional Performance With Intravascular Sensors to Assess the Narrowing Effect -Combined Pressure and Doppler FLOW Velocity Measurements) and IDEAL (Iberian-Dutch-English), a total of 133 vessels that underwent intracoronary Doppler flow measurement before and after percutaneous coronary intervention were analyzed. CFC classified prerevascularization lesions as normal (14), mildly reduced (40), moderately reduced (31), and severely reduced (48). Lesions with larger impairment of CFC showed greater increase in coronary flow and vice versa (median percent increase in coronary flow by revascularization: 4.2%, 25.9%, 50.1%, and 145.5%, respectively; P<0.001). Compared with the conventional cutoff values of fractional flow reserve, instantaneous wave-free ratio, and CFR, an ischemic CFC defined as moderately to severely reduced CFC showed higher diagnostic accuracy with higher specificity to predict a >50% increase in coronary flow after percutaneous coronary intervention. Receiver operating characteristic curve analysis demonstrated that only CFC has a superior predictive efficacy to CFR (P<0.05). Multivariate analysis revealed lesions with ischemic CFC to be the independent predictor of a significant coronary flow increase after percutaneous coronary intervention (odds ratio, 10.7; 95% CI, 4.6-24.8; P<0.001). Conclusions CFC showed significant improvement of identification of lesions that benefit from revascularization compared with CFR with respect to coronary flow increase. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT02328820.

[Myocardial perfusion single-photon emission computer tomography and coronary angiography results in patients with different pretest probability of ischemic heart disease]

AIM

To study the relationship between pretest probability (PTP) of ischemic heart disease (IHD), calculated according to the recommendations of the European Society of Cardiology (ESC) of 2013 and 2019, with the perfusion of the left ventricle of the myocardium according to the single-photon emission tomography (SPECT) and the results of the invasive coronary angiography (CAG).

MATERIAL AND METHODS

The study included 220 patients with a preliminary diagnosis of ischemic heart disease and planned invasive CAG. All patients underwent rest-stress perfusion myocardial SPECT within 1 month prior to or after CAG, standard quantitative parameters of left ventricular perfusion were assessed. Retrospectively clinical data was analyzed and PTP of IHD was assessed according to ESC recommendations for 2013 and 2019.

RESULTS

Invasive CAG revealed obstructive lesion of one or more coromary arteries in 204 of the 220 patients (92.7%). In a retrospective analysis, taking into account gender, age and nature of the complaints, as recommended by ESC in 2013, PTP was rated as low (15%) in 13 patients (5.9%), as intermediate (1585%) in 207 patients (94.1%). Following the comprehensive survey (SPECT and CAG) 8 patients with low PTP (61.5%) underwent coronary revascularization. Among patients with intermediate PTP significant transient ischemia according to SPECT was detected in 31 (15.0%), initial at 107 (51.7%). According CAG among patients with intermediate PTP obstructive lesion was found in 192 (92.7%), 113 patients (58.8%) underwent revascularization. According to ESC recommendations of 2019, PTP was rated as low (15%) in 117 patients (53.2%), including 514% in 98 (44.5%). According to a survey (SPECT and CAG) 68 of them (58.1%) underwent revascularization.

CONCLUSION

PTP measurements proposed by ESC can not be applied to patients of the Russian population with suspected ischemic heart disease without significant corrections. 2013 ESC recommendations with higher PTP values for all categories of patients reflect Russian population better, while 2019 recommendations mistakenly attribute patients to low PTP in at least 58% of cases. These results are preliminary and will be expanded in subsequent studies with more detailed analysis of PTP in included patients with suspected IHD.

Percutaneous or surgical revascularization is associated with survival benefit in stable coronary artery disease

Aims 

We assessed the association between early invasive therapy, burden of ischaemia, and survival benefit separately for percutaneous coronary intervention (PCI) and coronary artery bypass grafting (CABG). Ischaemia involving more than 10% of the left ventricular myocardium may identify patients who benefit from revascularization. However, it is not clear whether this association exists with both PCI and CABG.

Materials and results

Patients who underwent single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) between 1992 and 2012 were identified. Early revascularization was defined as PCI or CABG performed within 90 days of SPECT MPI. The association between early PCI or CABG and all-cause mortality was assessed using a doubly robust, propensity score matching analysis. In total, 54 522 patients were identified, with median follow-up 8.0 years. Early PCI was performed in 2688 patients and early CABG in 1228. In the matched cohorts, early revascularization was associated with improved survival compared to medical therapy in patients with more than 15% ischaemia for both PCI [adjusted hazard ratio (HR) 0.70, P = 0.002] and CABG (adjusted HR 0.73, P = 0.008).

Conclusion 

In this observational analysis, both PCI and CABG were associated with reduced all-cause mortality in the presence of moderate to severe ischaemia after adjusting for factors leading to revascularization. As the threshold for improved outcomes with revascularization was similar for PCI and CABG, our results suggest that decisions for PCI vs. CABG for early revascularization should be determined by coronary anatomy, patient characteristics, and shared decision making, but not by the burden of ischaemia.

ACR Appropriateness Criteria® Chest Pain-Possible Acute Coronary Syndrome

Chest pain is a frequent cause for emergency department visits and inpatient evaluation, with particular concern for acute coronary syndrome as an etiology, since cardiovascular disease is the leading cause of death in the United States. Although history-based, electrocardiographic, and laboratory evaluations have shown promise in identifying coronary artery disease, early accurate diagnosis is paramount and there is an important role for imaging examinations to determine the presence and extent of anatomic coronary abnormality and ischemic physiology, to guide management with regard to optimal medical therapy or revascularization, and ultimately to thereby improve patient outcomes. A summary of the various methods for initial imaging evaluation of suspected acute coronary syndrome is outlined in this document. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Transient ischaemic dilation and post-stress wall motion abnormality increase risk in patients with less than moderate ischaemia: analysis of the REFINE SPECT registry

AIMS

Ischaemia on single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) is strongly associated with cardiovascular risk. Transient ischaemic dilation (TID) and post-stress wall motion abnormalities (WMA) are non-perfusion markers of ischaemia with incremental prognostic utility. Using a large, multicentre SPECT MPI registry, we assessed the degree to which these features increased the risk of major adverse cardiovascular events (MACE) in patients with less than moderate ischaemia.

METHODS AND RESULTS

Ischaemia was quantified with total perfusion deficit using semiautomated software and classified as: none (<1%), minimal (1 to <5%), mild (5 to <10%), moderate (10 to <15%), and severe (≥15%). Univariable and multivariable Cox proportional hazard analyses were used to assess associations between high-risk imaging features and MACE. We included 16 578 patients, mean age 64.2 and median follow-up 4.7 years. During follow-up, 1842 patients experienced at least one event. Patients with mild ischaemia and TID were more likely to experience MACE compared with patients without TID [adjusted hazard ratio (HR) 1.42, P = 0.023], with outcomes not significantly different from patients with moderate ischaemia without other high-risk features (unadjusted HR 1.15, P = 0.556). There were similar findings in patients with post-stress WMA. However, in multivariable analysis of patients with mild ischaemia, TID (adjusted HR 1.50, P = 0.037), but not WMA, was independently associated with increased MACE.

CONCLUSION

In patients with mild ischaemia, TID or post-stress WMA identify groups of patients with outcomes similar to patients with moderate ischaemia. Whether these combinations identify patients who may derive benefit from revascularization deserves further investigation.

Prognostic significance of previous myocardial infarction and previous revascularization in patients undergoing SPECT MPI

BACKGROUND

Accurate risk stratification in patients with known coronary artery disease (CAD) is critical for patient management. Prior myocardial infarction (MI) or revascularization without MI are often equated as known CAD. We compared the prognostic significance of prior MI and previous revascularization in patients undergoing single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI).

METHODS

Consecutive patients undergoing SPECT MPI at Cedars-Sinai Medical Center between 1992 and 2012 were included. Medical history, including history of MI or revascularization, was collected prospectively. Association with all-cause mortality was assessed with multivariable Cox analysis, adjusted for patient demographics, medical history, medications, and SPECT MPI results.

RESULTS

In total, 50,121 patients were identified including 7428 (14.8%) with a history of previous MI and 3608 (7.2%) with a history of revascularization without prior MI. During a median follow-up of 8.0 years, 19,696 (39.3%) patients died including 4467 (60.1%) with a history of MI and 1880 (52.1%) with a history of revascularization. Prior MI (adjusted HR 1.12, p=0.001) and prior revascularization without MI (adjusted HR 1.15, p<0.001) were independently associated with increased all-cause mortality. Previous MI (adjusted HR 1.27, p<0.001) and previous revascularization without MI (adjusted HR 1.21, p<0.001) were significantly associated with increased all-cause mortality only in patients without ischemia.

CONCLUSIONS

In this large cohort of patients undergoing SPECT MPI, previous MI and previous revascularization without MI were independent predictors of all-cause mortality, with no significant difference in associated risk. History of CAD may be particularly important for risk stratification in patients without ischemia.

Effect of Coronary Anatomy and Myocardial Ischemia on Long-Term Survival in Patients with Stable Ischemic Heart Disease

Background The severity of coronary artery disease (CAD) and of ischemia are evaluated to guide therapy, but their relative prognostic importance remains uncertain. Accordingly, we sought to clarify their association with long-term survival in the COURAGE trial (Clinical Outcomes Utilizing Revascularization and Aggressive Drug Evaluation). Methods and Results Survival data from after the original trial period ended was obtained at 15 Veterans Affairs sites and 13 of 18 United States non-Veterans Affairs sites. Date of death was obtained from the Veterans Affairs system-wide Corporate Data Warehouse and the National Death Index. Of the original 2287 patients in COURAGE, 1370 (60%) had both stress perfusion imaging and quantitative coronary angiography available, with extended survival evaluated in 767 subjects. Survival was calculated by the Kaplan-Meier method, and a Cox proportional-hazards model adjusted for baseline differences. There were 369 all-cause deaths during a median follow-up of 7.9 years (range, 0-15 years). The number of coronary arteries diseased predicted survival (HR, 1.25; 95% CI, 1.09-1.43), whereas severity of ischemia did not (HR, 0.99; 95% CI, 0.80-1.22). Percutaneous coronary intervention did not offer a survival advantage over optimal medical therapy (HR, 0.95; 95% CI, 0.77-1.16) and there was no interaction between therapeutic strategy and number of coronary arteries diseased or severity of ischemia. In fully adjusted models, the number of coronary arteries diseased was not associated with increased mortality. Conclusions In univariate analysis, the number of coronary arteries diseased predicted long-term mortality, but severity of ischemia did not. Adjusted for baseline variables, neither assessment approach predicted mortality. Overall, there was no survival benefit from percutaneous coronary intervention in any subset defined by either angiographic or ischemic severity. Clinical Trial Registration: URL: https://www.clinicaltrials.gov . Unique identifier: NCT00007657.

Using High-Sensitivity Cardiac Troponin for the Exclusion of Inducible Myocardial Ischemia in Symptomatic Patients: A Cohort Study

BACKGROUND

The optimal noninvasive method for surveillance in symptomatic patients with stable coronary artery disease (CAD) is unknown.

OBJECTIVE

To apply a novel approach using very low concentrations of high-sensitivity cardiac troponin I (hs-cTnI) for exclusion of inducible myocardial ischemia in symptomatic patients with CAD.

DESIGN

Prospective diagnostic cohort study. (ClinicalTrials.gov: NCT01838148).

SETTING

University hospital.

PATIENTS

1896 consecutive patients with CAD referred with symptoms possibly related to inducible myocardial ischemia.

MEASUREMENTS

Presence of inducible myocardial ischemia was adjudicated using myocardial perfusion imaging with single-photon emission computed tomography, as well as coronary angiography and fractional flow reserve measurements where available. Staff blinded to adjudication measured circulating hs-cTn concentrations. An hs-cTnI cutoff of 2.5 ng/L, derived previously in mostly asymptomatic patients with CAD, was assessed. Predefined target performance criteria were at least 90% negative predictive value (NPV) and at least 90% sensitivity for exclusion of inducible myocardial ischemia. Sensitivity analyses were based on measurements with an hs-cTnT assay and an alternative hs-cTnI assay with even higher analytic sensitivity (limit of detection, 0.1 ng/L).

RESULTS

Overall, 865 patients (46%) had inducible myocardial ischemia. The hs-cTnI cutoff of 2.5 ng/L provided an NPV of 70% (95% CI, 64% to 75%) and a sensitivity of 90% (CI, 88% to 92%) for exclusion of inducible myocardial ischemia. No hs-cTnI cutoff reached both performance characteristics predefined as targets. Similarly, using the alternative assays for hs-cTnI or hs-cTnT, no cutoff achieved the target performance: hs-cTnT concentrations less than 5 ng/L yielded an NPV of 66% (CI, 59% to 72%), and hs-cTnI concentrations less than 2 ng/L yielded an NPV of 68% (CI, 62% to 74%).

LIMITATION

Data were generated in a large single-center diagnostic study using central adjudication.

CONCLUSION

In symptomatic patients with CAD, very low hs-cTn concentrations, including hs-cTnI concentrations less than 2.5 ng/L, do not generally allow users to safely exclude inducible myocardial ischemia.

PRIMARY FUNDING SOURCE

European Union, Swiss National Science Foundation, Kommission für Technologie und Innovation (Innosuisse), Swiss Heart Foundation, Cardiovascular Research Foundation Basel, University of Basel, University Hospital Basel, Roche, Abbott, and Singulex.

Contemporary Cardiac MRI in Chronic Coronary Artery Disease

Chronic coronary artery disease remains an unconquered clinical problem, affecting an increasing number of people worldwide. Despite the improved understanding of the disease development, the implementation of the many advances in diagnosis and therapy is lacking. Many clinicians continue to rely on patient's symptoms and diagnostic methods, which do not enable optimal clinical decisions. For example, echocardiography and invasive coronary catheterisation remain the mainstay investigations for stable angina patients in many places, despite the evidence on their limitations and availability of better diagnostic options. Cardiac MRI is a powerful diagnostic method, supporting robust measurements of crucial markers of cardiac structure and function, myocardial perfusion and scar, as well as providing detailed insight into myocardial tissue. Accurate and informative diagnostic readouts can help with guiding therapy, monitoring disease progress and tailoring the response to treatment. In this article, the authors outline the evidence supporting the state-of-art applications based on cardiovascular magnetic resonance, allowing the clinician optimal use of this insightful diagnostic method in everyday clinical practice.

Quantitative Clinical Nuclear Cardiology, Part 1: Established Applications

Single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) has attained widespread clinical acceptance as a standard of care for patients with known or suspected coronary artery disease (CAD). A significant contribution to this success has been the use of computer techniques to provide objective quantitative assessment in the standardization of the interpretation of these studies. Software platforms have been developed as a pipeline to provide the quantitative algorithms researched, developed and validated to be clinically useful so diagnosticians everywhere can benefit from these tools. The goal of this CME article (PART 1) is to describe the many quantitative tools that are clinically established and more importantly how clinicians should use them routinely in the interpretation, clinical management and therapy guidance of patients with CAD.

Baseline Characteristics and Risk Profiles of Participants in the ISCHEMIA Randomized Clinical Trial

Importance

It is unknown whether coronary revascularization, when added to optimal medical therapy, improves prognosis in patients with stable ischemic heart disease (SIHD) at increased risk of cardiovascular events owing to moderate or severe ischemia.

Objective

To describe baseline characteristics of participants enrolled and randomized in the International Study of Comparative Health Effectiveness With Medical and Invasive Approaches (ISCHEMIA) trial and to evaluate whether qualification by stress imaging or nonimaging exercise tolerance test (ETT) influenced risk profiles.

Design, Setting, and Participants

The ISCHEMIA trial recruited patients with SIHD with moderate or severe ischemia on stress testing. Blinded coronary computed tomography angiography was performed in most participants and reviewed by a core laboratory to exclude left main stenosis of at least 50% or no obstructive coronary artery disease (CAD) (<50% for imaging stress test and <70% for ETT). The study included 341 enrolling sites (320 randomizing) in 38 countries and patients with SIHD and moderate or severe ischemia on stress testing. Data presented were extracted on December 17, 2018.

Main Outcomes and Measures

Enrolled, excluded, and randomized participants' baseline characteristics. No clinical outcomes are reported.

Results

A total of 8518 patients were enrolled, and 5179 were randomized. Common reasons for exclusion were core laboratory determination of insufficient ischemia, unprotected left main stenosis of at least 50%, or no stenosis that met study obstructive CAD criteria on study coronary computed tomography angiography. Randomized participants had a median age of 64 years, with 1168 women (22.6%), 1726 nonwhite participants (33.7%), 748 Hispanic participants (15.5%), 2122 with diabetes (41.0%), and 4643 with a history of angina (89.7%). Among the 3909 participants randomized after stress imaging, core laboratory assessment of ischemia severity (in 3901 participants) was severe in 1748 (44.8%), moderate in 1600 (41.0%), mild in 317 (8.1%) and none or uninterpretable in 236 (6.0%), Among the 1270 participants who were randomized after nonimaging ETT, core laboratory determination of ischemia severity (in 1266 participants) was severe (an eligibility criterion) in 1051 (83.0%), moderate in 101 (8.0%), mild in 34 (2.7%) and none or uninterpretable in 80 (6.3%). Among the 3912 of 5179 randomized participants who underwent coronary computed tomography angiography, 79.0% had multivessel CAD (n = 2679 of 3390) and 86.8% had left anterior descending (LAD) stenosis (n = 3190 of 3677) (proximal in 46.8% [n = 1749 of 3739]). Participants undergoing ETT had greater frequency of 3-vessel CAD, LAD, and proximal LAD stenosis than participants undergoing stress imaging.

Conclusions and Relevance

The ISCHEMIA trial randomized an SIHD population with moderate or severe ischemia on stress testing, of whom most had multivessel CAD.

Trial Registration

ClinicalTrials.gov Identifier: NCT01471522.

PCI and CABG for Treating Stable Coronary Artery Disease: JACC Review Topic of the Week

Percutaneous coronary intervention (PCI) and coronary artery bypass grafting (CABG) are considered revascularization procedures, but only CABG can prolong life in stable coronary artery disease. Thus, PCI and CABG mechanisms may differ. Viability and/or ischemia detection to guide revascularization have been unable to accurately predict treatment effects of CABG or PCI, questioning a revascularization mechanism for improving survival. By contrast, preventing myocardial infarction may save lives. However, the majority of infarcts are generated by non-flow-limiting stenoses, but PCI is solely focused on treating flow-limiting lesions. Thus, PCI cannot be expected to significantly limit new infarcts, but CABG may do so through providing flow distal to vessel occlusions. All comparisons of CABG to PCI or medical therapy that demonstrate survival effects with CABG also demonstrate infarct reduction. Thus, CABG may differ from PCI by providing "surgical collateralization," prolonging life by preventing myocardial infarctions. The evidence is reviewed here.

Comparison of Exercise Performance and Clinical Outcome Between Functional Complete and Incomplete Revascularization

Background and Objectives

Although percutaneous coronary intervention (PCI) is recommended to improve symptoms in patients with stable ischemic heart disease (SIHD), improvement of exercise performance is controversial. This study aimed to investigate changes in exercise duration after PCI according to functional completeness of revascularization by comparing pre- and post-PCI exercise stress test (EST).

Methods

Patients with SIHD were enrolled from a prospective PCI registry, and divided into 2 groups: 1) functional complete revascularization (CR) group had a positive EST before PCI and negative EST after PCI, 2) functional incomplete revascularization (IR) group had positive EST before and after PCI. Primary outcome was change in exercise duration after PCI and secondary outcome was major adverse cardiac events (MACE, a composite of any death, any myocardial infarction, and any ischemia-driven revascularization) at 3 years after PCI.

Results

A total of 256 patients (149 for CR group, and 107 for IR group) were eligible for analysis. Before PCI, exercise duration was not significantly different between the functional CR and IR groups (median 540 [interquartile range; IQR, 414, 602] vs. 480 [402, 589] seconds, p=0.091). After PCI, however, the CR group had a significantly higher increment of exercise duration than the IR group (median 62.0 [IQR, 12.0, 141.0] vs. 30.0 [−11.0, 103.5] seconds, p=0.011). The functional CR group also had a significantly lower risk of 3-year MACE (6.2% vs. 26.1%; adjusted hazard ratio, 0.19; 95% confidence interval, 0.09–0.41; p<0.001).

Conclusions

Functional CR showed a higher increment of exercise duration than functional IR.

Long-Term Outcomes in Patients Undergoing Percutaneous Coronary Intervention with or without Preprocedural Exercise Stress Test

BACKGROUND

Although current guidelines recommend noninvasive stress tests prior to elective percutaneous coronary intervention (PCI), it is unknown whether antecedent exercise stress test (EST) affects the outcomes of patients undergoing PCI for stable ischemic heart disease (SIHD). This study aimed to investigate long-term outcomes in patients undergoing elective PCI with or without EST.

METHODS

We studied 2,674 patients undergoing elective PCI using drug-eluting stents for SIHD. Patients were divided into the 2 groups: the test group underwent EST with a positive result within 180 days prior to PCI (n = 668), whereas the non-test group did not undergo any noninvasive stress tests (n = 2,006). The primary outcome was all-cause death or myocardial infarction (MI).

RESULTS

Over 5 years after the index PCI, the risk of all-cause death or MI was significantly lower in the test group than in the non-test group in overall population (3.3% vs. 10.9%; adjusted hazard ratio [HR], 0.34; 95% confidence interval [CI], 0.22-0.55; P < 0.001), and in propensity score-matched population (668 pairs) (3.3% vs. 6.3%; adjusted HR, 0.52; 95% CI, 0.30-0.89; P = 0.018). However, the incidence of any revascularization was similar between the 2 groups in overall (16.7% vs. 16.8%; adjusted HR, 0.99; 95% CI, 0.79-1.25; P = 0.962) and matched population (16.7% vs. 18.3%; adjusted HR, 0.91; 95% CI, 0.70-1.19; P = 0.509).

CONCLUSION

Patients who underwent elective PCI with EST had a reduced risk of all-cause death or MI than those undergoing PCI without stress tests.

Nuclear investigative techniques and their interpretation in the heart and vascular disease

Over the last several decades, myocardial perfusion imaging with single photon emission tomography and positron emission tomography has been a mainstay for the evaluation of patients with known or suspected coronary artery disease non-invasively. Technical advances in imaging modalities and radiopharmaceutical have revolutionaries the understanding of pathogenesis and management of various diseases. In this article, we shall discuss the various available imaging nuclear medicine techniques, radiopharmaceutical, and common indications. In the era of “precision medicine,” imaging has to be patient centered. We will briefly review the upcoming areas of nuclear medicine imaging apart from perfusion imaging, such as advances in myocardial blood flow quantitation and molecular imaging.

Comparing Cardiac Magnetic Resonance-Guided Versus Angiography-Guided Treatment of Patients With Stable Coronary Artery Disease: Results From a Prospective Randomized Controlled Trial

OBJECTIVES

The purpose of this study was the prospective and randomized evaluation of cardiovascular endpoints and quality of life in patients with stable coronary artery disease comparing a cardiac magnetic resonance (CMR)-based management strategy with a coronary angiography-based approach.

BACKGROUND

Evidence from trials prospectively evaluating the role of CMR in clinical pathways and decision processes is limited.

METHODS

Patients with symptomatic CAD were randomized to diagnostic coronary angiography (group 1) or adenosine stress CMR (group 2). The primary endpoint was the composite of cardiac death and nonfatal myocardial infarction. Quality of life was assessed using the Seattle Angina Questionnaire at baseline and during follow-up.

RESULTS

Two hundred patients were enrolled. In group 1, 45 revascularizations (45.9%) were performed. In group 2, 27 patients (28.1%) were referred to revascularization because of ischemia on CMR. At 12-month follow-up, 7 primary events occurred: 3 in group 1 (event rate 3.1%) and 4 in group 2 (event rate 4.2%), with no statistically significant difference (p = 0.72). Within the next 2 years, 6 additional events could be observed, giving 4 events in group 1 and 9 events in group 2 (event rate 4.1% vs. 9.4%; p = 0.25). Group 2 showed significant quality-of-life improvement after 1 year in comparison to group 1.

CONCLUSIONS

A CMR-based management strategy for patients with stable coronary artery disease was safe, reduced revascularization procedures, and resulted in better quality of life at 12-month follow-up, though noninferiority could not be proved. Optimal timing for reassessment remains to be investigated. (Magnetic Resonance Adenosine Perfusion Imaging as Gatekeeper of Invasive Coronary Intervention [MAGnet]; NCT02580851).

Imaging in ESC clinical guidelines: chronic coronary syndromes

The European Society of Cardiology (ESC) has recently published new guidelines on the diagnosis and management of chronic coronary syndromes (CCS). The 2019 guideline identified six common clinical scenarios of CCS defined by the different evolutionary phases of coronary artery disease (CAD), excluding the situations in which an acute coronary event, often with coronary thrombus formation, dominates the clinical presentation. This review aims at providing a summary of novel or revised concepts in the guidelines together with the recent data underlying the major changes on the use of cardiac imaging in patients with suspected or known CCS.

Based on data from contemporary cohorts of patients referred for diagnostic testing, the pre-test probabilities of CAD based on age, sex and symptoms have been adjusted substantially downward as compared with 2013 ESC guidelines. Further, the impact of various risk factors and modifiers on the pre-test probability was highlighted and a new concept of ‘Clinical likelihood of CAD’ was introduced. Recommendations regarding diagnostic tests to establish or rule-out obstructive CAD have been updated with recent data on their diagnostic performance in different patient groups and impact on patient outcome. As the initial strategy to diagnose CAD in symptomatic patients, non-invasive functional imaging for myocardial ischaemia, coronary computed tomography angiography or invasive coronary angiography combined with functional evaluation may be used, unless obstructive CAD can be excluded by clinical assessment alone. When available, imaging tests instead of the exercise electrocardiogram are recommended when following the non-invasive diagnostic strategy.

Extent of Myocardial Ischemia on Positron Emission Tomography and Survival Benefit With Early Revascularization

BACKGROUND

Prior studies with single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) have shown a survival benefit with early revascularization in patients with >10% to 12.5% ischemic myocardium. The relationship among positron emission tomography (PET)-derived extent of ischemia, early revascularization, and survival is unknown.

OBJECTIVES

The purpose of this study was to evaluate the association among percent ischemia on PET MPI, revascularization, and survival.

METHODS

A total of 16,029 unique consecutive patients who were undergoing Rubidium-82 rest-stress PET MPI from 2010 to 2016 were included. Patients with known cardiomyopathy and nondiagnostic perfusion results were excluded. Percent ischemic myocardium was estimated from a 17-segment model. Propensity scoring was used to account for nonrandomized referral to early revascularization (90 days of PET). A Cox model was developed, adjusting for propensity scores for early revascularization and percent ischemia, and an interaction between ischemia and early revascularization was tested.

RESULTS

Median follow-up was 3.7 years. Overall, 1,277 (8%) patients underwent early revascularization and 2,493 (15.6%) died (738 cardiac). Nearly 37% of patients (n = 5,902) had ischemia, with 13.5% (n = 2,160) having ≥10%. In propensity-adjusted analyses, there was a significant interaction between ischemia and early revascularization (p < 0.001 for all-cause and cardiac death), such that patients with greater ischemia had improved survival with early revascularization, with a potential ischemia threshold at 5% (upper limit 95% confidence interval at 10%). There was no differential association between ischemia and early revascularization on death based on history of known coronary artery disease (interaction p = 0.72).

CONCLUSIONS

In a contemporary cohort of patients undergoing PET MPI, patients with greater ischemia had a survival benefit from early revascularization. On exploratory analyses, this threshold was lower than that previously reported for SPECT. These findings require future validation in prospective cohorts or trials.

Assessment of coronary physiology - the evidence and implications

Use of angiography for the assessment of coronary lesions is limited by its inability to provide information regarding the functional significance of stenoses. A number of studies have demonstrated the presence of ischaemia to be the most important determinant of the benefit associated with coronary revascularisation in stable coronary artery disease. Assessment of intra-coronary physiology can guide percutaneous coronary intervention, and is often used for angiographically borderline stenoses. There is now increasing evidence to suggest that more routine use can improve clinical outcomes. Fractional flow reserve (FFR) is the most established measure of intra-coronary physiology, but is currently under-utilised. The main drawback of FFR is the dependence on a pharmacological infusion to maintain hyperaemia. An alternative technique which measures flow at a specific point in the cardiac cycle (instantaneous wave-free ratio) has been developed which obviates the need for hyperaemia and may replace FFR as the default measure.

WITHDRAWN: Comparative accuracy of myocardial perfusion imaging: The final answer has yet to come

The Publisher regrets that this article is an accidental duplication of an article that has already been published, https://dx.doi.org/10.1016/j.ijcard.2019.07.027. The duplicate article has therefore been withdrawn. The full Elsevier Policy on Article Withdrawal can be found at https://www.elsevier.com/about/our-business/policies/article-withdrawal.

Cardiovascular magnetic resonance: Stressing the future

Non-invasive cardiac stress imaging plays a central role in the assessment of patients with known or suspected coronary artery disease. The current guidelines suggest estimation of the myocardial ischaemic burden as a criterion for revascularisation on prognostic grounds despite the lack of standardised reporting of the magnitude of ischaemia on various non-invasive imaging methods. Future studies should aim to accurately describe the relationship between myocardial ischaemic burden as assessed by cardiovascular magnetic resonance imaging and mortality.

Is There an Age When Myocardial Perfusion Imaging May No Longer Be Prognostically Useful?

BACKGROUND

Heart disease continues to be the leading cause of death, and the prevalence of coronary artery disease is expected to increase as the population ages. It is important to understand the clinical utility of medical tests, or its lack thereof, in the aging population. The objective of this study was to understand the incremental prognostic value of positron emission tomographic (PET) myocardial perfusion imaging in the elderly (≥85 years of age).

METHODS AND RESULTS

A total of 3343 patients enrolled in a multicenter observational PET registry were analyzed. Participants were initially divided into 3 age categories: 65 to 74.9, 75 to 84.9, and ≥85 years of age and followed for all-cause death. Median follow-up time was 3 years. Of the total patient population, 248 patients (49% men) were ≥85 years old. When compared with younger patients, individuals ≥85 years had a higher prevalence of hypertension (79%) and a lower incidence of dyslipidemia (54%) and diabetes mellitus (24%). On multivariable analysis, %left ventricular stress defect and %left ventricular ischemia were predictors of patient outcome for those <85 years of age but was not statistically significant in those ≥85 years of age. The prognostic value of PET (%left ventricular stress defect and %left ventricular ischemia) appeared to decrease with advancing age.

CONCLUSIONS

The elderly is a high-risk population irrespective of PET myocardial perfusion imaging results, and incremental prognostic value of PET myocardial perfusion imaging appears to wane in those ≥85 years of age. Although PET myocardial perfusion imaging may be diagnostically useful in the elderly, its prognostic value in this population requires further evaluation.

Quantitative Clinical Nuclear Cardiology, Part 1: Established Applications

SPECT myocardial perfusion imaging has attained widespread clinical acceptance as a standard of care for patients with known or suspected coronary artery disease. A significant contribution to this success has been the use of computer techniques to provide objective quantitative assessment in the standardization of the interpretation of these studies. Software platforms have been developed as a pipeline to provide the quantitative algorithms researched, developed and validated to be clinically useful so diagnosticians everywhere can benefit from these tools. The goal of this continuing medical education article (part 1) is to describe the many quantitative tools that are clinically established and, more importantly, how clinicians should use them routinely in interpretation, clinical management, and therapy guidance for patients with coronary artery disease.

Quantification of Myocardial Mass Subtended by a Coronary Stenosis Using Intracoronary Physiology

Background:

In patients with stable coronary artery disease, the amount of myocardium subtended by coronary stenoses constitutes a major determinant of prognosis, as well as of the benefit of coronary revascularization. We devised a novel method to estimate partial myocardial mass (PMM; ie, the amount of myocardium subtended by a stenosis) during physiological stenosis interrogation. Subsequently, we validated the index against equivalent PMM values derived from applying the Voronoi algorithm on coronary computed tomography angiography.

Methods:

Based on the myocardial metabolic demand and blood supply, PMM was calculated as follows: PMM (g)=APV×D 2 ×π/(1.24×10 − 3 ×HR×sBP+1.6), where APV indicates average peak blood flow velocity; D, vessel diameter; HR, heart rate; and sBP, systolic blood pressure. We calculated PMM to 43 coronary vessels (32 patients) interrogated with pressure and Doppler guidewires, and compared it with computed tomography–based PMM.

Results:

Median PMM was 15.8 g (Q1, Q3: 11.7, 28.4 g) for physiology-based PMM, and 17.0 g (Q1, Q3: 12.5, 25.9 g) for computed tomography–based PMM ( P =0.84). Spearman rank correlation coefficient was 0.916 ( P <0.001), and Passing-Bablok analysis revealed absence of both constant and proportional differences (coefficient A: −0.9; 95% CI, −4.5 to 0.9; and coefficient B, 1.00; 95% CI, 0.91 to 1.25]. Bland-Altman analysis documented a mean bias of 0.5 g (limit of agreement: −9.1 to 10.2 g).

Conclusions:

Physiology-based calculation of PMM in the catheterization laboratory is feasible and can be accurately performed as part of functional stenosis assessment.

Percutaneous coronary intervention for the management of stable ischemic heart disease

PURPOSE OF REVIEW

The purpose of this review is to summarize landmark studies and recent evidence in support for and against benefits of routine percutaneous coronary intervention (PCI) in the management of patients with stable ischemic heart disease (SIHD).

RECENT FINDINGS

Randomized controlled trials have raised uncertainty regarding the prognostic benefits of routine PCI in patients with SIHD. The benefits of PCI to improve symptoms and quality of life (QOL), thought to be more established, was brought into question recently by the ORBITA trial. Two hundred participants with single vessel SIHD optimized first on antianginal therapy were randomized to PCI or sham PCI procedure. At 6 weeks, there was no significant difference in the primary endpoint of exercise time increment (PCI minus sham PCI 16.6 s, 95% confidence interval -8.9 to 42.0 s, P = 0.20), or secondary endpoints of change in angina or QOL scores between the groups.

SUMMARY

Findings from this first placebo-controlled trial of PCI in patients with single vessel SIHD suggest that PCI need not necessarily be the first line or default strategy for symptomatic improvement. Results from the ongoing ISCHEMIA (International Study of Comparative Health Effectiveness with Medical and Invasive Approaches) trial will provide further guidance regarding symptomatic and prognostic benefits of early angiography and revascularization for higher risk SIHD patients with moderate-severe ischemia.

Complete revascularization determined by myocardial perfusion imaging could improve the outcomes of patients with stable coronary artery disease, compared with incomplete revascularization and no revascularization

OBJECTIVES

To compare the outcomes among patients treated by complete coronary revascularization (CCR) or incomplete coronary revascularization (ICR) and no coronary revascularization (NCR) by myocardial perfusion imaging (MPI), as well as to evaluate the impact of severity of ischemia on patients with coronary artery disease (CAD) by different therapy strategies.

BACKGROUND

Using myocardial ischemia severity determined by MPI guiding treatment strategies for CAD patients still lacks strong clinical evidences.

METHODS

Consecutive patients (N = 286) underwent clinical stress-rest SPECT MPI and were retrospectively followed-up. For assessment of outcome of treatment, all patients were classified into three groups (CCR, ICR, and NCR), and further divided into two subgroups as mild ischemia (< 10% ischemic myocardium) and moderate-severe ischemia (≥ 10% ischemic myocardium). All-cause death was defined as the primary endpoint, and the composite of deaths, nonfatal myocardial infarction, and repeat revascularization (MACE) as the secondary endpoint.

RESULTS

Two-hundred eighty-six patients were followed-up for 46 ± 21 months. Thirty deaths and 65 MACEs were recorded. Patients treated by revascularization had significantly lower MACE (P < .001) but not mortality (P = .158) than patients treated by NCR. Outcomes of CCR related to mortality rate were greater than ICR and NCR (death: P = .019, MACE: P < .001). In patients with moderate-severe ischemia, CCR showed improved outcomes than ICR and NCR (death: P = .034; and MACE: P < .001). In patients with mild ischemia, the outcomes of CCR, ICR, and NCR had no significant difference (P > .05). Multivariate regression Cox analysis revealed that summed difference score [death: HR 1.09 (1.03, 1.15), P = .004] was an independent risk factor and CCR was an independent negative predictor [death: HR 0.31 (0.12, 0.81), P = .017; MACE: HR 0.30 (0.16, 0.57), P < .001].

CONCLUSIONS

Outcomes of patients treated by CCR were most likely more promising in comparison with treatment of ICR and NCR, especially when patients had over 10% ischemic myocardium.

Quantification of Ischemia As a Prognostic Mandate for Coronary Revascularization in Asymptomatic Patients: How Much Is Enough?

The aim of this study was to investigate whether asymptomatic patients with known coronary artery disease and demonstrable myocardial ischemia warrant revascularization on prognostic grounds. A Medline and PubMed search was performed, including 7 trials with data discussed and concise reviews of prominent articles in the field. The magnitude of inducible ischemia in those with known coronary disease correlates closely with poor cardiovascular outcomes in terms of death, myocardial infarction, hospitalization, and revascularization. Patients with ≥10% inducible ischemia experience a survival advantage when revascularized with a reduction in mortality of greater than 50% regardless of symptoms (P < 0.00001). Evidence also suggests that left ventricular function remains preserved in those who are revascularized when compared with medical therapy alone; left ventricular ejection fraction 53.9% versus 48.8% (P < 0.001). Silent ischemia is a useful prognostic marker in those with known coronary disease. It is recommended that asymptomatic patients with known coronary disease be revascularized on prognostic grounds if ≥10% ischemia can be demonstrated on nuclear or myocardial perfusion scan, ≥3 segments of regional wall motion abnormality on stress echocardiography/cardiac magnetic resonance imaging, or ≥2 segments with perfusion deficits on stress perfusion cardiac magnetic resonance imaging.

Artificial Intelligence in Cardiovascular Medicine

PURPOSE OF REVIEW

The ripples of artificial intelligence are being felt in various sectors of human life. Machine learning, a subset of artificial intelligence, extracts information from large databases of information and is gaining traction in various fields of cardiology. In this review, we highlight noteworthy examples of machine learning utilization in echocardiography, nuclear cardiology, computed tomography, and magnetic resonance imaging over the past year.

RECENT FINDINGS

In the past year, machine learning (ML) has expanded its boundaries in cardiology with several positive results. Some studies have integrated clinical and imaging information to further augment the accuracy of these ML algorithms. All the studies mentioned in this review have clearly demonstrated superior results of ML in relation to conventional approaches for identifying obstructions or predicting major adverse events in reference to conventional approaches. As the influx of data arriving from gradually evolving technologies in health care and wearable devices continues to be more complex, ML may serve as the bridge to transcend the gap between health care and patients in the future. In order to facilitate a seamless transition between both, a few issues must be resolved for a successful implementation of ML in health care.

Artificial Intelligence in Cardiovascular Imaging: JACC State-of-the-Art Review

Data science is likely to lead to major changes in cardiovascular imaging. Problems with timing, efficiency, and missed diagnoses occur at all stages of the imaging chain. The application of artificial intelligence (AI) is dependent on robust data; the application of appropriate computational approaches and tools; and validation of its clinical application to image segmentation, automated measurements, and eventually, automated diagnosis. AI may reduce cost and improve value at the stages of image acquisition, interpretation, and decision-making. Moreover, the precision now possible with cardiovascular imaging, combined with "big data" from the electronic health record and pathology, is likely to better characterize disease and personalize therapy. This review summarizes recent promising applications of AI in cardiology and cardiac imaging, which potentially add value to patient care.

Coronary Angiography With Pressure Wire and Fractional Flow Reserve

BACKGROUND

Approximately 800 000 coronary angiography procedures are per- formed in Germany each year, mainly in order to identify coronary artery stenoses. As a rule, revascularization is indicated only when coronary artery stenoses cause relevant ischemia, but this cannot be determined unequivocally by angiography alone. Pressure wire measurement and the measurement of fractional flow reserve (FFR) enable direct evaluation of the hemodynamic relevance of coronary artery stenoses during diagnostic coronary angiography.

METHODS

This review is based on publications retrieved by a selective search in PubMed focusing especially on large randomized trials, registry studies, and meta- analyses on either pressure wire measurement or FFR.

RESULTS

According to a registry study from France, the hemodynamic evaluation of a stenosis during coronary angiography affected decisions about revascularization in 43% of cases. Randomized multicenter trials have shown that a combined end- point consisting of death, myocardial infarction, or revascularization arose signifi- cantly less commonly in the FFR group than in the group receiving angiography without FFR (13.2% versus 18.3%; p = 0.02), and that patients with one or more hemodynamically significant coronary artery stenoses (FFR ≤ 0.80) benefited more from revascularization than from medical management alone (event rate, 8.1% versus 19.5%; p <0.001). It was also shown that revascularization yields no benefit if relevant ischemia has been ruled out, even if the angiogram shows high-grade coronary artery stenoses.

CONCLUSION

All cardiac catheter laboratories should be capable of performing pres- sure wire measurements and measurements of FFR and should do so regularly if ischemia due to coronary artery stenosis cannot be demonstrated non-invasively. A pathological FFR measurement is an indication for revascularization.

Most Important Prognostic Values to Predict Major Adverse Cardiovascular, Cerebrovascular, and Renal Events in Patients with Chronic Kidney Disease Including Hemodialysis for 2 Years

Patients with chronic kidney disease (CKD) have an increased risk of adverse cardiovascular/cerebrovascular events. The aim of this study is to clarify whether stress myocardial perfusion single-photon emission computed tomography (SPECT) could predict cardiovascular/cerebrovascular events. In the Gunma-CKD SPECT Study, a multicenter prospective cohort trial, 311 patients with CKD (estimated glomerular filtration rate < 60 min/mL/1.73 m2) including 50 patients on hemodialysis underwent stress 99mTc-tetrofosmin SPECT for suspected ischemic heart disease and were followed for 2 years. The primary endpoint was the occurrence of cardiac death (CD), while the secondary endpoint was major adverse cardiovascular/cerebrovascular and renal events (MACCRE). MACCRE occurred in 91 out of 286 patients (CD in 13 and other MACCRE in 78 patients). According to a multivariate Cox analysis, hemoglobin (Hb) and end-systolic volume (ESV) were associated with CD (p < 0.05), while the summed difference score, diabetes mellitus (DM), and Hb were associated with MACCRE (p < 0.05). Kaplan-Meier analysis showed that the CD-free rate was higher in patients with ESV < 105 mL (log-rank, p = 0.0013), Hb > 12 g (log-rank, p = 0.0036), and a summed stress score < 6 (log-rank, p = 0.0058). The MACCRE-free rate was higher in patients with SDS = 0 (log-rank, p = 0.0097), without DM (log-rank, p = 0.0091), and with Hb > 12 g (log-rank, p = 0.0023). Myocardial perfusion SPECT parameters as well as renal anemia and DM can be reliable prognostic markers in patients with CKD including hemodialysis.

Advances in Management of Stable Coronary Artery Disease: the Role of Revascularization?

PURPOSE OF REVIEW

Coronary artery disease remains the most common cause of death worldwide. In patients with biomarker-positive acute coronary syndrome, the combination of guideline-directed medical therapy with routine revascularization is associated with improved outcomes. However, the role of routine revascularization in stable ischemic heart disease, in addition to medical therapy, remains a matter of debate. In this review, we aimed to describe the role of revascularization in stable ischemic heart disease.

RECENT FINDINGS

Revascularization is indicated in patients with stable ischemic heart disease and progressive or refractory symptoms, despite medical management. When guided by ischemia presence, revascularization has failed to show survival benefit, compared with medical therapy alone in multiple clinical trials. On the other hand, revascularization guided by coronary lesion severity, assessed by FFR or iFR, has been shown to offer survival benefit and improvement in symptom severity. PCI-revascularization of unprotected left main disease is feasible with comparable to surgical approach outcomes. Clinical decision to perform revascularization in stable ischemic heart disease necessitates a heart team approach, and no simple algorithm can guide this process. Further studies are required to assess the benefit of routine revascularization, in combination to medical therapy, in this population.

Prognostic Value of Vasodilator Stress Cardiac Magnetic Resonance Imaging: A Multicenter Study With 48 000 Patient-Years of Follow-up

Importance

Stress cardiac magnetic resonance imaging (CMR) is not widely used in current clinical practice, and its ability to predict patient mortality is unknown.

Objective

To determine whether stress CMR is associated with patient mortality.

Design, Setting, and Participants

Real-world evidence from consecutive clinically ordered CMR examinations. Multicenter study of patients undergoing clinical evaluation of myocardial ischemia. Patients with known or suspected coronary artery disease (CAD) underwent clinical vasodilator stress CMR at 7 different hospitals. An automated process collected data from the finalized clinical reports, deidentified and aggregated the data, and assessed mortality using the US Social Security Death Index.

Main Outcomes and Measures

All-cause patient mortality.

Results

Of the 9151 patients, the median (interquartile range) patient age was 63 (51-70) years, 55% were men, and the median (interquartile range) body mass index was 29 (25-33) (calculated as weight in kilograms divided by height in meters squared). The multicenter automated process yielded 9151 consecutive patients undergoing stress CMR, with 48 615 patient-years of follow-up. Of these patients, 4408 had a normal stress CMR examination, 4743 had an abnormal examination, and 1517 died during a median follow-up time of 5.0 years. Using multivariable analysis, addition of stress CMR improved prediction of mortality in 2 different risk models (model 1 hazard ratio [HR], 1.83; 95% CI, 1.63-2.06; P < .001; model 2: HR, 1.80; 95% CI, 1.60-2.03; P < .001) and also improved risk reclassification (net improvement: 11.4%; 95% CI, 7.3-13.6; P < .001). After adjustment for patient age, sex, and cardiac risk factors, Kaplan-Meier survival analysis showed a strong association between an abnormal stress CMR and mortality in all patients (HR, 1.883; 95% CI, 1.680-2.112; P < .001), patients with (HR, 1.955; 95% CI, 1.712-2.233; P < .001) and without (HR, 1.578; 95% CI, 1.235-2.2018; P < .001) a history of CAD, and patients with normal (HR, 1.385; 95% CI, 1.194-1.606; P < .001) and abnormal left ventricular ejection fraction (HR, 1.836; 95% CI, 1.299-2.594; P < .001).

Conclusions and Relevance

Clinical vasodilator stress CMR is associated with patient mortality in a large, diverse population of patients with known or suspected CAD as well as in multiple subpopulations defined by history of CAD and left ventricular ejection fraction. These findings provide a foundational motivation to study the comparative effectiveness of stress CMR against other modalities.

Clinical significance of chronic myocardial ischemia in coronary artery disease patients

Myocardial ischemia is considered the cornerstone of the treatment of patients with coronary artery disease (CAD). Although the deleterious effects of myocardial infarction, the maximum expression of ischemia, have been extensively studied and described, the clinical effects of chronic, documented myocardial ischemia are not completely clarified. The first studies that compared therapies for coronary disease focused on the presence of anatomical features and assessed ischemia based on the interpretation of the findings of obstructive atherosclerotic lesions. They suggested that revascularization interventions did not confer any clinical advantage over medical therapy (MT), in terms of cardiac or overall death. Other retrospective studies that were dedicated to assessing the impact of documented stress-induced ischemia on cardiovascular outcomes have suggested a prognostic impact of chronic ischemia. However, this has been questioned in recent studies. Moreover, the previous understanding that chronic ischemia could lead to worsening of ventricular function was not confirmed in a recent study. Thus, the prognostic significance of stress-induced ischemia has been questioned. Regarding treatment options, although some previous analyses have suggested that interventional therapies would reduce cardiovascular events in CAD patients with documented ischemia, recent post-hoc studies and metanalysis have shown distinct results. In this review article, the authors discuss myocardial ischemia, the different responses of the myocardium to ischemic insults, ischemic preconditioning, and the main findings of recent studies about the clinical aspects and treatment of patients with chronic, documented myocardial ischemia.