An EAPCI Expert Consensus Document on Ischaemia with Non-Obstructive Coronary Arteries in Collaboration with European Society of Cardiology Working Group on Coronary Pathophysiology & Microcirculation Endorsed by Coronary Vasomotor Disorders International Study Group

The performance of angiography-derived index of microcirculatory resistance for ischemia in angina with non-obstructive coronary artery disease: Validated by wire-based IMR and SPECT-MPI

BACKGROUND

Coronary microvascular dysfunction (CMD) accounts for a significant part of angina with non-obstructive coronary artery (ANOCA). Angiography-derived index of microcirculatory resistance (angio-IMR) has been developed for the evaluation of CMD but not yet validated sufficiently in ANOCA.

AIMS

To validate angio-IMR against wire-based IMR and to investigate its diagnostic performance for ischemia in ANOCA patients.

METHODS

This study included two independent cohorts. The angio-IMR and wire-based IMR were measured in 74 patients (74 vessels) in the wire-based IMR validation cohort. The angio-IMR and single-photon emission computed tomography-myocardial perfusion imaging (SPECT-MPI) were successfully completed in 136 patients (408 vessels) in the SPECT-MPI validation cohort. The ischemia was defined as the myocardial perfusion defect on SPECT-MPI and a summed difference score (SDS) ≥ 2.

RESULTS

In the wire-based IMR validation cohort, the angio-IMR ≥ 25 had the high diagnostic efficiency (area under the receiver-operating characteristics curve (AUC): 0.917, 95 %CI: 0.843-0.922; p < 0.001) and classification agreement (CA) (91.9 %) with the referenced wire-based IMR ≥ 25. In the SPECT-MPI validation cohort, more ischemia was observed in the high angio-IMR group (angio-IMR ≥ 25) compared to the low angio-IMR group (angio-IMR < 25) (55.2 % vs 10.4 %, p < 0.001). The angio-IMR ≥ 25 had a moderate diagnostic performance for ischemia (AUC: 0.759, 95 %CI: 0.670-0.849; p < 0.001), and it could improve the ability to discriminate ischemia in ANOAC patients (integrated discrimination improvement (IDI): 0.184; p < 0.001; net reclassification improvement (NRI): 0.217; p < 0.001).

CONCLUSION

The study demonstrates that angio-IMR, validated through both wire-based IMR and SPECT-MPI, presents a promising and convenient diagnostic approach for identifying ischemia in patients with ANOCA.

Invasive coronary function testing in clinical practice: Implementing the 2024 ESC guidelines on chronic coronary syndromes

Angina with non-obstructive coronary arteries (ANOCA) is increasingly recognized as a significant aspect of chronic coronary syndromes. These patients frequently experience recurrent angina, resulting in high healthcare costs and impaired quality of life. Invasive coronary function testing (ICFT) is able to identify ANOCA endotypes, which can guide treatment and improve quality of life. Despite Class II recommendations for invasive microvascular assessments in the previous 2019 European Society of Cardiology (ESC) Guidelines, ICFT has yet to translate into widespread clinical practice. Patients with ANOCA experience poor quality of life and reduced functional capacity, highlighting the need for earlier ICFT implementation. The 2024 ESC Guidelines now strongly recommend ICFT (Class I, level of evidence B) for patients with non-obstructive coronary arteries and persistent angina despite optimal medical therapy, and for confirming or excluding ANOCA in patients with uncertain diagnoses on non-invasive testing (Class I, level of evidence B). Consequently, a standardized approach to optimize the management of ANOCA patients is warranted. Therefore, this review aims to provide interventional cardiologists with a contemporary review of the literature and a practical guideline on implementation of ICFT. It will discuss the following subjects: the definitions of the different endotypes, an example of an ICFT protocol, discontinuation of medication prior to ICFT, use of radial cocktail, target vessel for testing, acetylcholine injection techniques and rechallenge, adenosine injection techniques, the order of testing, the interpretation of ICFT, safety and feasibility, and the pharmacological treatment.

Clinical standards in angina and non-obstructive coronary arteries: A clinician and patient consensus statement

Patients with angina and non-obstructive coronary arteries (ANOCA) or myocardial ischaemia with non-obstructive coronary arteries (INOCA) comprise a relatively large subgroup within those with ischaemic heart disease. Advances in the understanding of disease mechanisms, diagnostic tests and multidisciplinary care are improving awareness of the needs of affected individuals. However, practice variations and suboptimal management promulgate the health burden and increase health care resource consumption. Clinical standards represent a limited number of quality statements that describe the care patients should be offered by health professionals and providers for a specific clinical condition or defined clinical pathway in line with current best evidence. Clinical standards should address implementation of this evidence along with education of patients and healthcare professionals, multidisciplinary care networks, and research. In this consensus statement, we highlight contemporary evidence and stakeholder views, including clinicians and patients, to provide an international perspective for developing clinical standards for services involving ANOCA/INOCA patients. A clinical service for ANOCA/INOCA should "consider the whole patient" and provide a multidisciplinary, patient-centred service.

Association between the Tpeak-Tend interval on admission and coronary microvascular dysfunction in Takotsubo syndrome

AIMS

The Tpeak-Tend interval on electrocardiogram may be a predictor of worse outcomes in Takotsubo syndrome (TTS), but the mechanisms have not been fully determined. This study aimed to investigate the relationships between the corrected Tpeak-Tend (cTp-e) interval and coronary microvascular-dysfunction (CMD) assessed by the angiography-derived index of microvascular resistance (Angio-IMR) and the in-hospital prognosis in patients with TTS.

METHODS AND RESULTS

We retrospectively evaluated 111 consecutive patients admitted for TTS who underwent coronary angiography at Kindai University Hospital from October 2009 to July 2023. The Tpeak-Tend interval was defined as the time interval between the peak and the end of the T wave in electrocardiogram lead V5 on admission. Angio-IMR was assessed from aortic pressure, quantitative flow ratio (QFR), vessel length and hyperemic velocity using the formula described in validation studies. QFR, vessel length and hyperemic velocity was derived from coronary angiography and QAngio XA 3D software package. The degree of CMD was assessed by the maximum Angio-IMR value in each of the three coronary arteries. The primary endpoint was the relationship between the grade of a prolonged cTp-e interval on admission and Angio-IMR. The secondary endpoint was the relationship between the grade of a prolonged cTp-e interval on admission and in-hospital adverse cardiovascular events (composite of acute heart failure, cardiogenic shock, life-threatening arrhythmia, thrombotic events, stroke and all-cause death). The median age was 77.5 [71.0-83.0] years, and most patients were women (82.0%). The median cTp-e interval was 114.5 [91.2-147.0] ms. The patients were categorized according to the tertiles of the cTp-e interval (T1: 52.4-96.9 ms; T2: 100.1-129.1 ms; T3: 131.7-309.8 ms). There was a stepwise increment in the values of maximum Angio-IMR in each of the three coronary arteries in tertiles of the cTp-e interval (T1 vs. T2 vs. T3: 16.1 [14.7-19.3] vs. 21.8 [16.0-31.1] vs. 29.0 [27.2-31.9], P < 0.001). In-hospital adverse cardiovascular events occurred in 53 of 111 patients (47.7%). There was a stepwise increment in the incidence of in-hospital adverse cardiovascular events in tertiles of the cTp-e interval (T1 vs. T2 vs. T3: 27.1% vs. 54.1% vs. 62.2%, P = 0.007). The multivariable analysis showed that prolonged cTp-e interval (OR: 1.30; 95% CI: 1.12-1.56; P < 0.001) was independent predictors of in-hospital adverse cardiovascular events.

CONCLUSIONS

The Tpeak-Tend interval on admission reflected CMD and predicts in-hospital adverse cardiovascular events in patients with TTS.

Influence of fluctuations in fasting blood glucose on left ventricular function in patients with type 2 diabetes mellitus and coronary microcirculation dysfunction: a prospective cohort study

AIMS

To examine the effects of fluctuations in fasting blood glucose (FBG) levels on left ventricular function in patients with T2DM and coronary microcirculation dysfunction (CMD).

METHODS

A total of 290 patients with T2DM who received glucose-lowering therapy during hospitalization and were subsequently followed up for 18 months at the First Affiliated Hospital of Harbin Medical University, were enrolled in this study. 135 were diagnosed with CMD and were assigned to the CMD group, whereas 155 patients without CMD were allocated to the non-CMD group. The fasting blood glucose coefficient of variation (FBG-CV) was calculated for all participants. The CMD group was further stratified into three subgroups based on their FBG-CV values: CMD1 (FBG-CV > 25%), CMD2 (FBG-CV 15% ~ 25%), and CMD3 (FBG-CV < 15%). The left ventricular function, assessed by left ventricular ejection fraction (LVEF) and the E/e' ratio, was compared within each group before and after the follow-up period. This study was registered in the Chinese Clinical Trial Register, ChiCTR-ORC-16009800.

RESULTS

After the end of follow-up, the E/e' ratio in CMD1 was significantly higher than that in CMD2 and CMD3 (14.35 vs 8.57; p < 0.01; 14.35 vs 6.61; p < 0.01), and the E/e' ratio in CMD2 was significantly higher than that in CMD3 (8.57 vs 6.61; p < 0.01). Compared to the baseline measurements, the E/e' ratio in CMD1 showed a significant increase after an average 17.8 months of follow up (14.35 vs 8.44; p < 0.001). We found elevated E/e' ratio was associated with an increased FBG-CV level (odds ratio [OR]: 2.571; 95% CI 1.819-3.634; p < 0.001). In multivariate logistic analysis, course of diabetes (OR:1.062; 1.016-1.11; P = 0.007) and CMD (OR:2.231; 1.303-3.819; P = 0.003), were significantly associated with elevated E/e' ratio, while oral stains drugs (OR = 0.412 95% CI 0.237-0.715; P = 0.002) and insulin injections (OR = 0.536 95% CI 0.311-0.924; P = 0.025) behaved as a protective factor.

CONCLUSIONS

Our study clarified the association between FBG-CV levels and the E/e' ratio in a prospective cohort study. In T2DM patients with CMD, FBG-CV > 25% may adversely affect left ventricular diastolic function, whereas an optimal FBG-CV is considered to be less than 15%.

Novel Contrast-Derived Indices of Coronary Microvascular Function: Potential Clinical and Cost Benefits

BACKGROUND

Intravenous adenosine induces stable myocardial hyperemia for coronary microvascular function testing. Iodinated radiographic contrast media induce transient, submaximal hyperemia. We assessed the feasibility, diagnostic value, and potential cost-effectiveness of contrast-derived indices of microvascular function.

METHODS

Coronary flow reserve, index of microvascular resistance, and microvascular resistance reserve were assessed using a diagnostic guidewire. Intracoronary bolus thermodilution injections were performed at rest, immediately after an 8-mL bolus of iohexol, repeated after a second 8-mL bolus, and during intravenous adenosine infusion. Receiver operating characteristic analyses assessed the discriminatory ability of the contrast-derived indices (contrast-derived coronary flow reserve, contrast-derived index of microcirculatory resistance, contrast-derived microvascular resistance reserve) to detect abnormal adenosine-derived indices (coronary flow reserve <2.0, index of microvascular resistance ≥25, and microvascular resistance reserve <2.1).

RESULTS

Among 106 coronary arteries from 93 patients (median age 63 years; 62% female; 13% with diabetes), 88% of assessments were undertaken in the left anterior descending artery. Median fractional flow reserve was 0.88 (interquartile range, 0.85-0.92). Contrast-derived coronary flow reserve <2.0 (area under the curve 0.81; sensitivity 67%, specificity 80%, positive predictive value 40%, negative predictive value 92%), contrast-derived index of microcirculatory resistance >47 (area under the curve 0.82; 80%, 79%, 60%, 91%), and contrast-derived microvascular resistance reserve <1.9 (area under the curve 0.82; 67%, 89%, 35%, 97%) were best for predicting their adenosine-derived counterpart indices. There was good correlation on repeatability testing from the second contrast bolus. A hybrid approach reduced adenosine use by 40%, saving $30 800 (USA) or £8000 (UK) per 1000 vessels assessed.

CONCLUSIONS

Contrast-derived indices have high specificity and negative predictive value, enabling rapid exclusion of microvascular dysfunction. This method is feasible, clinically useful and cost-saving compared with routine adenosine testing.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT04674449.

Exercise-Induced Reduction in Left Ventricular Ejection Fraction in the Absence of Coronary Artery Disease: Clinical Characteristics and Outcomes

BACKGROUND

During exercise stress echocardiography (ESE), there are patients with normal left ventricular ejection fraction (LVEF) who paradoxically develop reduced LVEF during exercise despite absence of coronary artery disease (CAD) and a significant hypertensive response. This study sought to describe the clinical features and outcomes of this population.

METHODS

Among ESEs performed between 2003 and 2022, patients without CAD by angiogram within 90 days of ESE and resting LVEF ≥50% with a ≥5% LVEF decrease during ESE were included. Outcomes assessed were all-cause mortality, heart failure (HF) hospitalization, and atrial fibrillation (AF). Kaplan-Meier and Cox regression methods were used to analyze time-to-event outcomes.

RESULTS

Among 213,643 ESE, 134 patients met the eligibility criteria. The mean age of the population was 66 ± 10 years, 76% were women, and 16% had AF at baseline. Mean LVEF was 58% ± 4% at rest and 43% ± 4% at peak stress. Stress ECG met the criteria for ischemia in 14% of these patients. The 10-year estimated incidence of HF hospitalization was 17.6% (95% CI, 9.0%-26.2%). Among the subgroup without AF at baseline, the 10-year estimated incidence of developing AF was 23.4% (95% CI, 13.4%-33.4%). The 10-year estimated incidence of all-cause mortality was 12.9% (95% CI, 5.5%-20.3%), with 89% of deaths occurring due to noncardiovascular causes.

CONCLUSION

Patients with exercise-induced reduction in LVEF in the absence of obstructive CAD have a high incidence of HF hospitalizations and AF. The underlying pathophysiology of this disease process needs to be further investigated.

[Conservative Management of Chronic Coronary Syndrome]

CCS management, based on the 2024 ESC Guidelines, a cornerstone of contemporary cardiology, aims to prevent cardiovascular events, alleviate symptoms, and enhance quality of life through conservative and invasive strategies. Non-invasive approaches, encompassing patient education, lifestyle interventions, and optimized pharmacological treatments, have demonstrated significant benefits in prognosis and quality of life. The guidelines advocate for a patient-centered approach, tailoring therapies to pathophysiological mechanisms, comorbidities, and individual needs. Pharmacological strategies integrate antithrombotic, lipid-lowering, RAAS-blocking, anti-inflammatory, and antidiabetic agents for event prevention, alongside antianginal medications for symptom relief. Invasive interventions remain essential for high-risk patients with obstructive coronary artery disease (e.g., left main disease, three-vessel disease, or proximal LAD involvement) or refractory angina despite optimal medical therapy. However, the growing efficacy of medical management increasingly challenges the incremental benefits of early revascularization. The guidelines also highlight underdiagnosed conditions such as ANOCA (Angina with Non-Obstructive Coronary Arteries) and INOCA (Ischemia with Non-Obstructive Coronary Arteries). Recognizing diverse endotypes, including microvascular dysfunction and vasospastic angina, enables precise and individualized therapeutic approaches. Conservative therapy remains the foundation of CCS management, demanding a holistic, multidisciplinary, and patient-centered approach to optimize outcomes and improve quality of life.

Non-invasive imaging assessment in angina with non-obstructive coronary arteries (ANOCA)

Due to its significant prevalence and clinical implications, angina with non-obstructive coronary arteries (ANOCA) has become a major focus in modern cardiology. In fact, diagnosing ANOCA presents a significant challenge. The final diagnosis is often difficult, delayed, and frequently necessitates an invasive assessment through coronary angiography. However, recent improvements in non-invasive cardiac imaging allow a diagnosis of ANOCA using a combination of clinical evaluation, anatomical coronary imaging, and functional testing. This narrative review aims to critically assess various non-invasive diagnostic methods and propose a multimodal approach to diagnose ANOCA and tailor appropriate treatments.

Design and rationale of the efficacy of endothelin receptor antagonism in treatment of coronary artery spasm: a randomized controlled trial (EDIT-CAS)

Patients with angina and no obstructive coronary artery disease frequently have vasomotor dysfunction as the underlying mechanism for symptoms. Patients with vasomotor dysfunction have a high angina burden and their treatment frequently fails to reduce complaints sufficiently. Targeted therapies are currently unavailable due to heterogeneity in the patient population and incomplete understanding of the underlying pathophysiological mechanisms. One of the vasomotor dysfunction endotypes, epicardial spasm, is hypothesized to be a possible target for endothelin receptor antagonism treatment. The EDIT-CAS trial is a registry based, double blind, randomised, placebo-controlled clinical trial and aims to compare the efficacy of 10 weeks of add-on bosentan treatment versus placebo to prevent epicardial spasm at repeat spasm provocation test. Secondary and explorative outcomes are the effect on anginal complaints, safety of bosentan treatment, changes in coronary reactivity and the relationship between baseline endothelin levels and treatment success. We will include 100 patients with previously diagnosed epicardial vasospasm on a maximal triggering dose of 100 micrograms of acetylcholine and continuing angina(-like) symptoms at least weekly despite optimal medical treatment.

Challenges in diagnosing coronary microvascular dysfunction and coronary vasospasm

Chronic coronary syndromes (CCS) include 2 overlapping subgroups of patients - those with angina with nonobstructive coronary arteries (ANOCA), or ischaemia with non-obstructive coronary arteries (INOCA). A diagnosis of ANOCA-INOCA, is common and should be considered where angina is present and/or ischaemia is found on functional imaging in the absence of obstructive coronary artery disease (CAD) on coronary computed tomography angiography (CCTA) or invasive coronary angiography (ICA) (Ford and Berry, 2019). This review aims to provide an overview of contemporary challenges in the diagnosis of coronary microvascular dysfunction (CMD) and vasospastic disease, with a focus on recent guideline changes and current controversies. CMD and vasospastic angina (VSA) are increasingly acknowledged as an important and frequently overlooked, under investigated, and undertreated entities that contribute to ANOCA-INOCA (Samuels et al., 2023; Kunadian et al., 2020; Ford and Berry, 2019; Burgess and Mamas, 2024).

Non-invasive and quantitative evaluation of myocardial PET imaging: Next step for advanced therapy

Myocardial positron emission tomography (PET) is superior in detecting ischemia in patients with left main or multivessel disease, conditions that are challenging to assess using single-photon emission computed tomography (SPECT). Additionally, quantitative measurements of myocardial blood flow and myocardial flow reserve (MFR) have been established as significant prognostic indicators for patients with ischemic heart disease. Moreover, 13N-ammonia PET offers high temporal and spatial resolution, enabling the assessment of both left and right ventricular strain, a quantitative marker of regional myocardial wall motion. Ongoing research aims to translate these advanced PET-based methodologies into SPECT imaging. Furthermore, MFR has proven valuable for diagnosing and predicting cardiac allograft vasculopathy in heart transplant recipients. More recently, it has also been utilized to evaluate the efficacy of cardiac regeneration therapy in individuals with severe heart failure and reduced cardiac function. This review presents existing evidence and highlights recent advancements in myocardial PET.

Comparative outcomes of invasive versus conservative strategy in stable coronary artery disease patients: a risk-stratification-based hypothesis-generative study

BACKGROUND

Whether percutaneous coronary intervention (PCI) can improve the long-term prognosis of patients with stable coronary artery disease (SCAD) in comparison to conservative treatment remains controversial. The present study sought to evaluate the impacts of initial invasive versus conservative strategy on long-term clinical outcomes for patients with SCAD stratified by risk scores.

METHODS

This was a sub-analysis of the multicenter, observational Optimal antiPlatelet Therapy for Chinese patients with Coronary Artery Disease (OPT-CAD) study. Clinical outcomes were compared in SCAD patients who initially received PCI (invasive strategy) or conservative treatment according to risk stratification by OPT-CAD score. The primary outcome was ischemic events at 5 years, composed of cardiac death, myocardial infarction, and ischemic stroke. Secondary outcomes included all-cause death, Bleeding Academic Research Consortium (BARC) types 2, 3, or 5, and 3 or 5 bleeding.

RESULTS

The conservative group comprised 1767 (58.0%) patients and the invasive group comprised 1278 (42.0%) patients. Overall, invasive strategy did not reduce the risk of ischemic events compared with conservative strategy but was associated with an increased risk of BARC 2, 3, or 5 bleeding (adjusted hazard ratio (HR), 1.59; 95% confidence interval (CI), 1.13-2.26; P = 0.009). Similar results were observed in the low-risk patient subset (N = 2030). While in the moderate-to-high-risk subset (N = 1015), invasive strategy was associated with a reduced risk of ischemic events (HR, 0.67; 95% CI, 0.48-0.95; P = 0.02) and all-cause death (HR, 0.73; 95% CI, 0.51-1.03; P = 0.07), and with no excessive risk of bleeding.

CONCLUSIONS

Invasive strategy could not confer additional clinical benefits in patients with SCAD compared to conservative strategy, except in patients at moderate-to-high risk. The OPT-CAD risk score may be valuable to the guidance of optimal treatment strategy in SCAD patients.

The under-representation of women in cardiovascular clinical trials: State-of-the-art review and ethical considerations

This review describes and evaluates the representation of women in cardiovascular randomized controlled trials (RCT), it reports significant under-representation of women in clinical trials both as participants and researchers and discusses the ethical implications of under-representation. The under-representation of women as participants in cardiovascular RCTs is evident in trials investigating cardiovascular drugs, acute coronary syndrome, heart failure and interventional procedures and devices. Under-representation of women is also evident in the authorship of cardiovascular clinical trials and in trial leadership roles, and under-representation of women as trial investigators is independently associated with under- recruitment of women as trial participants. A notable lack of RCTs investigating conditions that disproportionately affect women is also evident, this triad of underrepresentation for women as participants, and investigators, and the lack of RCTs into conditions predominantly experienced by women, all contribute to the gender gap in cardiovascular outcomes. Better representation of women in clinical trials, in trial leadership and authorship is a key factor to address to equity, distributive justice and improve outcomes for women with cardiovascular disease.

Efficacy and safety of Shexiang Baoxin Pill in patients with angina and non-obstructive coronary arteries: A multicenter, randomized, double-blind, placebo-controlled, phase Ⅳ clinical trial

INTRODUCTION

Solid evidence generated from large studies supporting the recommendation of Shexiang Baoxin Pill (MUSKARDIA) as a promising treatment for angina and nonobstructive coronary arteries (ANOCA) populations is lacking.

OBJECTIVE

To evaluate the efficacy and safety of MUSKARDIA in patients with ANOCA.

METHODS

In this randomized, double-blind, placebo-controlled, phase IV trial, we enrolled 239 patients with ANOCA at 11 centers across China between May 2021 and July 2023. Patients were randomly assigned in a 1:1 ratio to receive MUSKARDIA or placebo (orally 4 pills thrice daily) based on conventional treatment for 12 weeks. The primary endpoint was the change in angina-related outcomes, assessed using the Seattle Angina Questionnaire (SAQ) scores for the treatment groups at week 12.

RESULTS

Among 239 randomized patients with ANOCA, 236 (MUSKARDIA group, n = 117; placebo group, n = 119) completed treatment and endpoint assessments. At week 12, patients in the MUSKARDIA group showed better angina-related outcomes, with a more rapid increase in SAQ scores, than those in the placebo group (all p < 0.0001). Statistically significant differences favoring MUSKARDIA over placebo were observed for change in angina attack frequency compared with baseline at week 12 (p < 0.0001). Meanwhile, according to the Canadian Cardiovascular Society grading of angina, the change in angina pectoris severity, compared with baseline, was significantly reduced in MUSKARDIA group compared with placebo group at week 12 (p < 0.0001). The percentage of patients who did not use sublingual nitroglycerin was noticeably higher in MUSKARDIA group than that in placebo group (84.16 % vs. 58.33 %; p < 0.001). The incidence of adverse events did not differ significantly between the two groups, and no serious adverse events occurred.

CONCLUSION

This randomized, placebo-controlled clinical trial firstly confirmed that MUSKARDIA was an effective, safe, and well-tolerated treatment for patients with ANOCA in clinical settings. This study was registered at ClinicalTrials.gov (NCT04897126).

Safety, Feasibility, and Diagnostic Yield of Invasive Coronary Function Testing: Netherlands Registry of Invasive Coronary Vasomotor Function Testing

Importance

Patients with angina and no obstructive coronary artery disease frequently have coronary vasomotor dysfunction as underlying pathophysiological mechanism, comprising epicardial spasm, microvascular spasm, and/or microcirculatory dysfunction. These endotypes can be diagnosed by invasive coronary function testing which has previously shown to be safe in tertiary and expert centers.

Objective

To determine the prevalence of vasomotor dysfunction in patients with angina and no obstructive coronary artery disease who were clinically referred for a coronary function test (CFT); and assess safety and feasibility of a CFT.

Design, Setting, and Participants

This quality improvement study was performed using the Netherlands Registry of Invasive Coronary Vasomotor Function Testing (NL-CFT), a prospective, observational registry, in 15 participating hospitals (2 tertiary and 13 nontertiary). Patients with angina and no obstructive coronary artery disease who were referred for a clinically indicated CFT between December 2020 and January 2024 were included.

Main Outcomes and Measures

A complete CFT consisted of acetylcholine spasm provocation testing and assessment of microcirculatory function. Prevalence of different endotypes based on test results and overall safety were assessed.

Results

Among a total of 1207 patients included, 978 (81%) were female; and the mean (SD) age was 60 (10) years. The prevalence of coronary vasomotor dysfunction was very high (78%). There were 11 (0.9%) major and 10 (0.8%) minor complications reported. Of them, 3 major and all minor were definitely related to the coronary function test. No procedural death, myocardial infarction, or stroke was observed. No differences were found in the occurrence of complications between tertiary and nontertiary centers.

Conclusions and Relevance

This study found that a CFT was feasible and safe to perform in both tertiary and nontertiary centers with a high diagnostic yield.

Diagnosing and treating stable angina: a contemporary approach for practicing physicians

Longer life expectancy and advancements in coronary artery disease management have improved life expectancy and survival, increasing the prevalence of chronic coronary syndromes (CCS). Angina is a common symptom in patients with CCS but remains underdiagnosed and undertreated. Contemporary guidelines provide detailed information on diagnosing and treating angina based on evidence and expert consensus; however, their extensive nature may hinder uptake by non-specialists. This review presents a practical approach to diagnosing stable angina, followed by the three pillars of CCS management: 1) healthy lifestyle including appropriate exercise, diet, and avoiding toxic habits; 2) optimal medical therapy, including treatment recommended to prevent cardiovascular events and drugs for the control of myocardial ischemia and angina tailored to the patient's comorbidities; and 3) myocardial revascularization when indicated. This approach may be useful for practicing physicians but is not intended to substitute more detailed and authoritative documents. Checklists are proposed to help focus patient-physician interactions and make follow-up visits more efficient. This approach seeks to increase the proportion of correct angina diagnoses and patients receiving evidence-based treatments, emphasizing the importance of patient education, managing residual angina, and reducing cardiovascular risk. We include reference to the recently published 2024 ESC guidelines on chronic coronary syndromes.

Evaluating patients with chest pain in the emergency department

Identifying patients with chest pain that is of cardiac origin is crucial owing to the high mortality and morbidity of cardiovascular diseases. History, electrocardiogram, and cardiac biomarkers are the core elements of the assessment. High sensitivity cardiac troponins (hs-cTn) are the preferred biomarkers for diagnosing acute myocardial infarction, allowing for more accurate detection and exclusion of myocardial injury. However, elevations in hs-cTn can occur in patients who are not experiencing acute myocardial infarction. Therefore, it is important for clinicians to recognize how to integrate hs-cTn levels into their clinical decision making process. Structured risk assessments, using evidence based diagnostic protocols, should be employed to estimate the risk of acute coronary syndrome and adverse events in patients with chest pain. Clinical decision pathways should be used routinely in emergency departments. Patients at intermediate or high risk of obstructive coronary artery disease might benefit from cardiac imaging and further testing. Patients should be involved in decision making, with information provided about risks, radiation exposure, costs, and alternative options to facilitate informed decision making.

Ischaemia with non-obstructive coronary arteries in the 2024 European Society of Cardiology guidelines for the management of chronic coronary syndromes

AIMS

Chronic coronary syndromes (CCS) occur commonly in the absence of flow-limiting epicardial coronary stenosis. Ischaemia or angina with non-obstructive coronary arteries (INOCA/ANOCA) may be caused by coronary microvascular disease, coronary artery spasm, myocardial bridging, diffuse atherosclerosis, or a combination of disorders.

METHODS AND RESULTS

We highlight the new recommendations in the 2024 European Society of Cardiology (ESC) guidelines on CCS relevant to the diagnosis and management of INOCA/ANOCA. The guidelines place a new emphasis on consideration of INOCA/ANOCA early during cardiovascular risk stratification and the initial diagnostic workup for chest pain. There is a new Class I recommendation for the availability of invasive coronary function testing (CFT) at the time of initial coronary angiography, when the mechanisms of chest pain are uncertain after non-invasive testing, and in patients with established INOCA/ANOCA who have persistent symptoms and poor quality of life despite medical therapy. Once underlying disorders have been identified based on the results of invasive CFT, the ESC guidelines emphasize a patient-centred, mechanism-based approach to medical treatment of INOCA/ANOCA to improve the symptoms and quality of life.

CONCLUSION

The 2024 ESC CCS guidelines provide a new vision for the diagnosis and management of ANOCA/INOCA, with an expanded role for invasive CFT and targeted medical therapy to improve symptoms and quality of life in patients with angina.

Management of angina pectoris

Angina pectoris, a primary manifestation of ischemic heart disease, imposes a significant clinical and economic burden globally. This review highlights recent advancements in the management of angina, emphasizing a patient-centred approach that integrates pharmacological, interventional, and lifestyle strategies to reduce cardiovascular risk and improve patient outcomes. For obstructive coronary artery disease, optimal medical therapy represents the cornerstone of treatment. Individualized regimens should be tailored to clinical factors such as blood pressure, heart rate, left ventricular function, comorbidities like heart failure and diabetes, concomitant medications, patient preferences, and drug availability. Myocardial revascularization is reserved for select cases to alleviate symptoms or improve prognosis. For angina or ischemia with non-obstructive coronary arteries (ANOCA/INOCA), precise endotype classification, differentiating microvascular angina, vasospastic angina, mixed type and non-coronary chest pain, enables personalized treatment strategies. Lifestyle interventions, including smoking cessation, weight management, adherence to Mediterranean diet, and exercise therapy, are essential components of care, promoting improved cardiovascular outcomes and quality of life. Structured exercise programs, particularly within cardiac rehabilitation settings, have demonstrated efficacy in enhancing functional capacity and reducing adverse events. Emerging therapies, including pharmacological agents and novel interventional approaches such as the coronary sinus reducer, hold promise for addressing unmet needs in refractory angina and challenging ANOCA/INOCA cases. Future directions should prioritize the integration of precision medicine, digital health technologies, and multidisciplinary care to optimize outcomes and advance personalized angina management.

Sex-Related Differences in the Prognostic Role of Acetylcholine Provocation Testing

BACKGROUND

Intracoronary provocation testing with acetylcholine (ACh) is helpful to diagnose and risk-stratify patients with ischemia with nonobstructed coronary arteries (NOCA) and myocardial infarction with NOCA. This study explored potential sex-related disparities on the prognostic significance of ACh provocative testing.

METHODS

Consecutive patients with ischemia with NOCA and those with myocardial infarction with NOCA who underwent ACh provocation testing were enrolled. The primary end point was the incidence of major adverse cardiovascular and cerebrovascular events at follow-up. Co-primary end points were angina recurrence and quality of life assessed by 12-month Seattle Angina Questionnaire (SAQ) summary score.

RESULTS

A total of 519 patients (mean age, 61.4±12.1 years; 275 [53.0%] women and 244 [47%] men) were enrolled: 346 (66.7%) with ischemia with NOCA and 173 (33.3%) with myocardial infarction with NOCA. A positive ACh test was observed in 274 (52.8%) patients, with a lower prevalence of epicardial spasm (82 [56.2%] versus 106 [82.8%]) and a higher prevalence of microvascular spasm (64 [43.8%] versus 22 [17.2%]) in women compared with men (P>0.001). After a median 22-month follow-up, major adverse cardiovascular and cerebrovascular events occurred in 53 (10.2%) patients, without significant sex differences (P>0.05). Men with a positive ACh test had a significantly higher rate of major adverse cardiovascular and cerebrovascular events (22 [17.2%] versus 5 [4.3%], P=0.002) compared with those with a negative test; no difference was observed in women (P>0.05) (P for interaction=0.003). Women with a positive test experienced a higher rate of angina recurrence (61 [41.8%] versus 32 [24.8%], P=0.005) and a lower SAQ summary score (82 [interquartile range, 72-90] versus 86 [interquartile range, 78-100], P<0.001) compared with those with a negative result; no difference was observed in men (P>0.05).

CONCLUSIONS

This study revealed the importance of recognizing sex-specific differences in the prognostic value of ACh testing for proper management of coronary vasomotor disorders.

Quantitative perfusion by cardiac magnetic resonance imaging reveals compromised myocardial perfusion in patients with angina with non-obstructive coronary artery disease

INTRODUCTION

Stress perfusion cardiac magnetic resonance (CMR) effectively detects myocardial ischemia. In angina with non-obstructive coronary arteries (ANOCA), visually assessed first-pass perfusion often appears normal. Automated quantitative perfusion (QP) might benefit ANOCA diagnosis, offering absolute quantification of myocardial blood flow (MBF) and myocardial perfusion reserve (MPR).

AIM

We aimed to evaluate the efficacy of QP in detecting ANOCA.

METHODS

This study compared fully automated QP CMR in ANOCA patients with age- and sex-matched healthy controls. Participants underwent adenosine stress perfusion CMR, including visual assessment and quantification of MBF and MPR. ANOCA patients underwent coronary function testing to identify vasospasm and/or coronary microvascular dysfunction.

RESULTS

Twenty-four ANOCA patients (83% women, 57 ± 9 years) and 25 healthy controls (80% women, 56 ± 7 years) were included. Visual perfusion assessment did not differ between groups (p = 0.54). Additionally, no differences in resting MBF were observed. However, ANOCA patients had significantly lower global MBF during stress (2.43 ± 0.72 vs 2.99 ± 0.65 ml/g/min, p < 0.01) and a significantly lower global MPR (2.24 ± 0.79 vs 2.68 ± 0.64, p = 0.04) compared to healthy controls. MPR was significantly reduced in the RCA territory in ANOCA patients (2.16 ± 0.71 vs 2.69 ± 0.69, p = 0.01), with no significant differences in other coronary territories. MPR did not significantly differ between ANOCA endotypes.

CONCLUSIONS

ANOCA patients display reduced global MPR, suggesting compromised perfusion. Variation in MPR across coronary territories highlights the importance of assessing perfusion in all teritories. These findings are promising and support the use of QP for non-invasive detection of vasomotor dysfunction in ANOCA patients.

PRE-REGISTERED CLINICAL TRIAL NUMBER

The pre-registered clinical trial number is NL-OMON23861.

Underpinnings of Heart Failure With Preserved Ejection Fraction in Women - From Prevention to Improving Function. A Co-publication With the American Journal of Preventive Cardiology and the Journal of Cardiac Failure

Heart failure with preserved ejection fraction (HFpEF) represents a major clinical challenge with rising global prevalence. Women have a nearly double lifetime risk of developing HFpEF compared to heart failure with reduced ejection fraction (HFrEF). In HFpEF, sex differences emerge both in how traditional cardiovascular risk factors (such as hypertension, obesity, and diabetes) affect cardiac function and through distinct pathophysiological mechanisms triggered by sex-specific events like menopause and adverse pregnancy outcomes. These patterns influence not only disease development, but also therapeutic responses, necessitating sex-specific approaches to treatment. This review aims to synthesize existing knowledge regarding HFpEF in women including traditional and sex-specific risk factors, pathophysiology, presentation, and therapies, while outlining important knowledge gaps that warrant further investigation. The impact of HFpEF spans a woman's entire lifespan, requiring prevention and management strategies tailored to different life stages. While understanding of sex-based differences in HFpEF has improved, significant knowledge gaps persist. Through examination of current evidence and challenges, this review highlights promising opportunities for innovative research, therapeutic development, and clinical care approaches that could transform the management of HFpEF in women.

ANOCA, INOCA, MINOCA: The New Frontier of Coronary Syndromes

The growing prevalence in the diagnosis of INOCA (Ischemia with Non-Obstructive Coronary Arteries), ANOCA (Angina with Non-Obstructive Coronary Arteries), and MINOCA (Myocardial Infarction with Non-Obstructive Coronary Arteries) highlights the need to reassess their clinical relevance. Historically regarded as benign syndromes, emerging evidence suggests that these conditions may cause serious cardiovascular events and considerable long-term disability. Additionally, emerging studies suggest that non-obstructive coronary artery disease (CAD) may have a higher prevalence compared to traditional obstructive forms of CAD. This leads to the need to better clarify the underlying pathogenic mechanisms as well as the risk factors associated with these syndromes. This is precisely the aim of this review, which focuses on the complex and heterogeneous mechanisms underlying these syndromes as well as the associated risk factors. This review also sums up the diagnostic steps necessary to achieve an accurate diagnosis, along with the interventional and pharmacological approaches to be implemented in light of the latest evidence.

Myocardial ischaemia following COVID-19: a cardiovascular magnetic resonance study

The pathophysiology of myocardial injury following COVID-19 remains uncertain. COVID-HEART was a prospective, multicentre study utilising cardiovascular magnetic resonance (CMR) to characterise COVID-related myocardial injury. In this pre-specified analysis, the objectives were to examine (1) the frequency of myocardial ischaemia following COVID-19, and (2) the association between ischaemia and myocardial injury. We studied 59 patients hospitalised with COVID-19 and elevated serum troponin (COVID + /troponin + , age 61 ± 11 years) and 37 control subjects without COVID-19 or elevated troponin and similar by age and cardiovascular comorbidities (COVID -/comorbidity + , 64 ± 10 years). Subjects underwent multi-parametric CMR (comprising assessment of ventricular volumes, stress perfusion, T1/T2 mapping and scar). The primary endpoint was the frequency of inducible myocardial ischaemia. Inducible ischaemia was evident in 11 (19%) COVID + /troponin + patients and in 8 (22%) control subjects (p = 0.72). In COVID + /troponin + patients with ischaemia, epicardial coronary disease pattern ischaemia was present in eight patients and microvascular disease pattern, in three patients. There was no significant difference in the frequency of inducible ischaemia in COVID + /troponin + patients with previous myocardial infarction and/or revascularisation compared to those without (2/12 [17%] vs. 9/47 [19%] respectively, p = 0.84), or in those with and without scar (7/27 [26%] vs. 4/32 [13%] respectively, p = 0.19). Myocardial ischaemia was present in ~ 20% of patients recently hospitalised with COVID-19 and with elevated cardiac troponin, but this was not different to matched comorbid controls. This finding coupled with the lack of an association between ischaemia and myocardial scar suggests that coronary artery abnormalities are unlikely to be the predominant mechanism underlying COVID-19 induced myocardial injury.

Clinical implications of coronary microvascular dysfunction in patients with non-obstructive coronary artery disease and role of the thermodilution method

More than 60% of patients undergoing coronary angiography present no coronary artery disease (CAD). Angina and myocardial ischemia are classically determined by epicardial vascular obstruction, but coronary microvascular dysfunction (CMD) may also represent a possible cause for these phenomena. Two endotypes of CMD have been recognized, with two different pathophysiological mechanisms: structural CMD, characterized by low coronary flow reserve (CFR) and high microvascular resistance (MVR) values; and functional CMD, characterized by low CFR and normal MVR values. According to the present data, almost half of patients with non-obstructive CAD have shown signs of CMD. For this reason, further investigations for microvascular function assessment should be considered when evaluating no-CAD patients complaining of angina or presenting signs of myocardial ischemia. The thermodilution method is currently becoming a widespread invasive technique due to its feasibility and high reproducibility for coronary physiology evaluation. Furthermore, a recently introduced technique - called continuous thermodilution - allows for direct measurement of absolute coronary flow and resistances. The role of this brand-new technique in the clinical scenario is however still to be fully investigated and its use is at present limited to research purposes only. Among no-CAD patients, both structural and functional CMD are related to a worse prognosis in term of mortality and major adverse cardiovascular events (MACE). In this review, we will discuss the present evidence supporting the definition, prevalence and clinical implication of the different forms of CMD and the technical aspects of its invasive assessment.

[Guidelines of the European Society of Cardiology on chronic coronary syndrome from 2024]

The 2024 European Society of Cardiology (ESC) guidelines on chronic coronary syndrome comprehensively summarize the symptoms, diagnostics and treatment of coronary artery disease, excluding acute coronary syndromes. The processing always begins with an estimation of the clinical probability, which should include not only the symptom profile but also the number of cardiovascular risk factors and is further modified by any conspicuous findings in electrocardiography (ECG), exercise testing, or echocardiography. For further diagnostics, coronary angiography via computed tomography is the first-line approach if the probability lies between 5% and 50%. For probabilities of 50-85% procedures for imaging-based ischemia detection are indicated, while for even higher probabilities immediate invasive diagnostics are given priority. The treatment includes intensive risk modification, medicinal anti-anginal treatment and finally revascularization by coronary intervention or bypass surgery. In the absence of high-risk constellations a medication-based approach should be initially preferred, with revascularization indicated if symptoms persist. The new guidelines also extensively address angina and ischemia without obstructive coronary lesions. In this context, intensive risk modification and initial medication treatment are again recommended.

Functional assessment in angina and non-obstructive coronary arteries: from microvascular resistance reserve to subtypes of coronary microvascular dysfunction

AIMS

Coronary microvascular dysfunction (CMD) is a heterogeneous condition defined by reduced coronary flow reserve (CFR). The new index 'microvascular resistance reserve' (MRR) has been developed, but its role is unclear. We investigate the relationships between functional indices in ANOCA (angina and non-obstructive coronary arteries) patients and evaluate the hemodynamic features of different CMD subtypes.

METHODS

We enrolled consecutive ANOCA patients assessed by using the bolus thermodilution technique. CFR, index of microcirculatory resistance (IMR) and MRR were estimated and correlated with each other. Patients were divided into two groups based on CMD presence (CFR < 2.5). Subsequently, high-hyperaemic-resistance (HHR) and low-hyperaemic-resistance (LHR) CMD subtypes were defined according to IMR values (cut-off 25). Microvascular flow and resistance were estimated both at rest and during hyperaemia with Tmnrest/IMRrest and Tmnhyp/IMR, respectively. All functional indices were compared between groups.

RESULTS

In total, 108 patients were enrolled: 66 patients in the normal group (CFR ≥ 2.5), 20 in the HHR-CMD group (CFR < 2.5 and IMR ≥ 25) and 22 in the LHR-CMD group (CFR < 2.5 and IMR < 25). MRR strongly correlated (r = 0.968, P < 0.01) with CFR, showing a good discriminatory power (area under the curve = 0.97) and accuracy (85%) for detecting CMD. LHR-CMD patients showed reduced microvascular resistance (IMRrest 34.3 ± 15.1, P < 0.01) and increased resting flow (Tmnrest 0.37 ± 0.17, P < 0.01), while HHR-CMD patients had impaired hyperaemic flow (Tmnhyp 0.45 ± 0.24 P < 0.01). MRR was reduced in CMD patients (P < 0.01), with no differences between CMD subtypes (P = 0.66).

CONCLUSIONS

In ANOCA patients, MRR and CFR are strongly correlated and could be considered as functionally interchangeable tools. IMR is crucial for differentiating CMD endotypes.

The role of non-invasive stress testing in the diagnosis of coronary microvascular disease

BACKGROUND

Angina with non-obstructive coronary artery disease (ANOCA) is commonly observed in patients with stable angina undergoing coronary angiography. Current guidelines recommend non-invasive stress testing as the first step in diagnosing coronary microvascular disease (CMD). This study aims to evaluate the diagnostic value of non-invasive stress testing in patients invasively diagnosed with CMD.

METHODS

We conducted a retrospective analysis of prospectively collected data. Eligible subjects were patients with angina who underwent NIST evaluation (echocardiography/ electrocardiography stress test or single-photon emission computerized tomography) prior to coronary angiography. All patients underwent invasive evaluation of microvascular function, which included the assessment of Coronary Flow Reserve, Index of Microcirculatory Resistance, and Resistive Reserve Ratio.

RESULTS

Overall, 140 patients (77 women, 67 ± 10 y/o) underwent NIST evaluation prior to coronary angiography, of whom 81 % were positive for ischemia. There was no difference in the prevalence of positive NIST between patients with abnormal compared with normal microvascular function tested invasively (81 % vs 82 %, p = 0.94). The prevalence of CMD was similar between patients with positive versus negative NIST (51 % vs 50 %, p = 0.94). Among 114 patients with positive NIST, 56 (49.2 %) had normal microvascular function, regardless of the type of stress test used (p = 0.94), the suspected territory of ischemia (p = 0.15), or the estimated severity of the ischemia (p = 0.63).

CONCLUSION

Non-invasive stress testing may have a limited predictive value in the diagnosis of CMD in ANOCA patients. Larger prospective studies are required for better understanding of the role these tests in the diagnosis and definition of CMD.

Paroxysmal Atrial Fibrillation during Spasm Provocation Test with Acetylcholine: Clinical Characteristics of Patients and Effect on Coronary Microvascular Function Measurements

BACKGROUND

Atrial fibrillation (AF) is a complication that occurs following a spasm provocation test (SPT) with acetylcholine (ACh). However, the characteristics of patients with AF remain unclear. Furthermore, the association of AF with the outcome of the coronary microvascular function test (CMFT) is unknown. This study aimed to evaluate whether patients with angina with non-obstructive coronary artery disease (ANOCA) who developed AF during SPT with ACh had any clinical characteristics. Additionally, we assessed the association of AF with the CMFT results.

METHODS

We included 123 patients with ANOCA who underwent SPT and CMFT. We defined AF as AF during ACh provocation. The coronary arteries that demonstrated AF before CMFT were defined as AF vessels (n = 21) and those in sinus rhythm (SR) were defined as SR-1 vessels (n = 165). Vessels that were restored to sinus rhythm immediately following AF were defined as AF-SR vessels (n = 29) and those that remained in sinus rhythm for some time were defined as SR-2 vessels (n = 136). Coronary flow reserve (CFR) and index of microcirculatory resistance (IMR) were obtained, and CFR of <2.0 and/or IMR of ≥25 were diagnosed as coronary microvascular dysfunction (CMD).

RESULTS

Of the 123 patients, 31 (25%) had AF but with no characteristic patient background. CFR was significantly lower in AF vessels than in SR-1 vessels (p = 0.035) and IMR did not differ between the two groups (p = 0.918). A study of the three groups that included AF-SR vessels revealed that IMR tended to be lower in AF-SR vessels than in the SR-2 and AF vessels (p = 0.089), and that the frequency of IMR of ≥25 was significantly lower than in the other two groups (p = 0.016).

CONCLUSIONS

AF occurred in 25% of SPTs with ACh, but the predictive clinical context remains unclear. Our results indicated that AF may affect the outcome of the CMFT. Thus, decisions for CMD management should be made with caution in the presence of AF.

FFR, iFR, CFR, and IMR: Results from clinical trials

In this review article, we provide an overview of the definition and application of fractional flow reserve (FFR), instantaneous wave-free ratio (iFR), coronary flow reserve (CFR), and index of microvascular resistance (IMR) in the diagnosis, prognosis, and management of coronary microvascular dysfunction. We discuss their respective limitations as it relates to microvascular dysfunction. In each section, we review the most recent evidence supporting their use in microvascular and epicardial coronary artery disease. We also highlight specific clinical conditions with emerging indications for the use of these indices, including in the setting of microvascular dysfunction due to acute myocardial infarction, heart failure with preserved ejection fraction, and post-cardiac transplant.

Diagnosis and Management of Acute Coronary Syndrome Patients Without Obstructive Epicardial Stenosis

PURPOSE OF REVIEW

What is the pathophysiology and clinical findings as well as management of patients presenting with INOCA/MINOCA (Ischemia/Myocardial Infarction with Non-Obstructive Coronary Arteries).

RECENT FINDINGS

INOCA/MINOCA has a complex pathophysiology. In this review article, we aim to summarize the complex pathophysiology and clinical diagnosis, and review the current management options.

Evolution of Coronary Microvascular Dysfunction Prevalence over Time and Across Diagnostic Modalities in Patients with ANOCA: A Systematic Review

Background: A considerable number of patients with angina undergo invasive coronary angiography, which might reveal non-obstructive coronary arteries (ANOCA). In this setting, they might have coronary microvascular disease (CMD). Its prevalence significantly varies in the literature. This systematic review aims to document the prevalence of CMD over time according to the diagnostic modalities. Methods: A systematic literature review was conducted using PubMed, the Cochrane Library, and Embase, covering publications from inception to 1 May 2024. Among 1471 identified articles, 297 full-text articles were assessed for eligibility. All studies reporting the prevalence of CMD in ANOCA patients based on invasive coronary artery (ICA), positron emission tomography-computed tomography (PET-CT), transthoracic echocardiography (TTE), or cardiac magnetic resonance (CMR) were included. Results: The review included 53 studies (published between 1998 and 2024), encompassing a total of 16,602 patients. Of these studies, 23 used ICA, 15 used PET-CT, 8 used TTE, and 7 used CMR. A statistically significant increase in CMD prevalence over time was observed across all diagnostic modalities (p < 0.05), except for PET-CT, which showed a consistent and stable prevalence over time. Notably, the prevalence rates from all of the diagnostic methods converged towards the 50% prevalence detected by PET-CT. Conclusions: The prevalence of CMD in patients with ANOCA is subject to debate. However, the current data suggest that regardless of the diagnostic method used, the most recent studies tend to converge towards a prevalence value of 50%, which has been consistently reported by PET-CT from the beginning.

Non-atherosclerotic coronary causes of myocardial infarction in women

Ischemic heart disease is the most common cardiovascular cause of death in women worldwide. Obstructive coronary atherosclerosis is the primary cause of myocardial infarction (MI), however, non-atherosclerotic mechanisms of MI, such as spontaneous coronary artery dissection, vasospasm, microvascular dysfunction, embolization, inflammation, coronary anomalies, infectious and infiltrative causes are increasingly being recognized. Emerging data suggest that women are two to five times more likely to have an MI in the absence of coronary atherosclerosis compared to men, but they continue to remain underdiagnosed and undertreated, partly due to underdiagnosis and limited understanding of these mechanisms. Recent advancements in invasive and noninvasive imaging techniques and physiological testing allow for distinguishing these mechanisms from each other, providing a definitive diagnosis and tailored treatment. This review summarizes the existing literature on the non-atherosclerotic coronary causes of MI with a focus on evidence pertaining to women, offering a basis for future studies.

Known yet underdiagnosed: Invasive assessment of coronary microvascular disease and its implications

Coronary microvascular disease (CMD) is one of the commonest causes of cardiac chest pain. The condition is more prevalent in women, and incidence is known to increase with age, hypertension, and diabetes. The pathophysiological pathways are heterogenous and related to intrinsic vascular and endothelial dysfunction. Furthermore, this entity is known to be associated with adverse cardiovascular outcomes. Despite this, there is inertia amongst cardiologists to further evaluate patients with non-critical coronary artery disease and suspected CMD. With refinement in technology, we have now better understanding of CMD and invasive testing in the catheterization laboratory is a viable option for confirming the diagnosis of CMD. However, despite advances in diagnosing and stratifying this entity, therapeutic options remain limited and poorly defined. In this editorial, we will briefly focus on the pathophysiology and invasive assessment and therapeutic options available for CMD.

The Role of Circulating Biomarkers in Patients with Coronary Microvascular Disease

Coronary microvascular disease (CMD) comprises a spectrum of conditions characterized by the functional and structural abnormalities of coronary microcirculation, affecting vessels typically smaller than 500 μm. Despite its clinical significance as a contributor to myocardial ischemia, CMD frequently remains underdiagnosed due to the limitations of current diagnostic approaches. Invasive testing, including coronary reactivity assessment, is considered the gold standard, but it is resource-intensive and not always accessible. Non-invasive methods, such as positron emission tomography (PET) and transthoracic Doppler echocardiography (TTDE), offer alternatives but are limited by varying accuracy and accessibility. Amid these diagnostic challenges, there is increasing interest in circulating biomarkers as adjuncts in CMD evaluation. Biomarkers associated with endothelial dysfunction, inflammation, and oxidative stress, detectable through routine blood tests, may assist in CMD diagnosis, risk stratification, and therapeutic monitoring. These biomarkers can offer insights into CMD pathogenesis and enable early, non-invasive screening to identify patients who may benefit from more invasive investigations. This narrative review examines studies assessing biomarkers in CMD patients with diagnoses confirmed through invasive techniques. Our objective is to focus on circulating biomarkers linked to the invasive evaluation of coronary microcirculation, aiming to advance the understanding of the underlying mechanisms of this prevalent condition and enhance diagnostic accuracy and the clinical management of affected patients.

Angina Severity and Symptom Improvement Are Associated With Diagnostic Acetylcholine Provocation Dose in Vasospastic Angina

BACKGROUND

A coronary function test (CFT) is the recommended diagnostic test to identify coronary vasomotor dysfunction as a cause of symptoms in patients with angina and nonobstructive coronary arteries (ANOCA). Acetylcholine is the commonly used pharmacological agent for spasm provocation. We aimed to investigate an association between severity of symptoms and provocative acetylcholine dose.

METHODS AND RESULTS

We included ANOCA patients undergoing clinically indicated CFT from the Netherlands Registry of Invasive Coronary Vasomotor Function Testing: NL-CFT. Patients with epicardial spasm (n=251) were divided according to acetylcholine spasm triggering dose: low (2-20 mcg, EpiLOW), middle (100 mcg, EpiMIDDLE) or high (200 mcg, EpiHIGH). Patients with microvascular spasm (n=157) were analyzed irrespective of triggering dose. The patient groups were compared to each other and to a control group with negative CFT results (n=101). We assessed mean Seattle Angina Questionnaire angina frequency and summary scores at baseline and follow-up and the proportion of patients improving or deteriorating. An inverse relationship between provocation dosage and angina frequency at baseline was found in epicardial spasm: the lower the triggering dose, the more frequently patients experienced angina (EpiLOW 48±20, EpiMIDDLE 53±21, EpiHIGH 57±19, microvascular spasm 61±21, controls 64±21, overall P=0.003). A trend was seen toward most patients improving in the high triggering dose group, and most patients deteriorating in the low triggering dose group.

CONCLUSIONS

A significant dose-dependent relationship between spasm provocation and anginal complaints exists. Acetylcholine provocation dose could be incorporated as a risk stratification factor or surrogate outcome in future clinical trials.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT06083155.

The additional impact of metabolic syndrome on left ventricular deformation and myocardial energetic efficiency impairment in ischemia with nonobstructive coronary arteries patients

BACKGROUND

Ischemia with nonobstructive coronary arteries (INOCA) has high morbidity, mortality, and poor quality of life. Metabolic syndrome (MetS) is a complex of multiple cardiac metabolic risk factors, significantly increasing the risk of major adverse cardiovascular events in INOCA patients. The study aimed to investigate the aggravating effect of MetS on left ventricular (LV) deformation and function impairment in INOCA patients.

MATERIALS AND METHODS

This study collected 104 INOCA patients (INOCA [MetS-]: n = 56; INOCA [MetS+]: n = 48) and 41 sex- and age-matched controls. LV function, indexed myocardial energetic efficiency (MEEI), and LV global peak strains (including radial, circumferential, and longitudinal directions) were measured among the three groups. The independent factors of reduced MEEI and impaired LV function and strain parameters for all INOCA patients were assessed using multivariable linear regression analyses.

RESULTS

In contrast to the INOCA (MetS-) group, the indexed LV stroke volume (LVSVI) (49.57 ± 11.58 mL/m2 vs. 42.58 ± 12.23 mL/m2, p = 0.007), MEEI [0.85(0.70-1.03) ml/s/g vs. 0.75(0.54-0.91) ml/s/g, p = 0.045] and LV global longitudinal peak strain (GLPS) (- 13.26 ± 2.86% vs. -10.95 ± 3.93%, p = 0.001) reduced in the INOCA (MetS+) group. Compared with the controls, LV GLPS decreased in the INOCA (MetS-) group (- 15.14 ± 2.83% vs. -13.26 ± 2.86%, p = 0.017). MetS was negatively associated with LVSVI, MEEI, and LV GLPS (all p < 0.05). After multivariable adjustment, MetS was found to be an independent factor of decreased LVSVI (β = -0.231, p = 0.012), MEEI (β = -0.262, p = 0.009), and LV GLPS (β = -0.266, p = 0.002) in INOCA patients. Using calcium channel blockers medication (β = 0.320, p = 0.001) and hypertension (β = -0.298, p = 0.002) were also independently associated with impaired MEEI.

CONCLUSIONS

MetS aggravated LV deformation and function impairment in patients with INOCA. MetS was found to be an independent factor of impaired MEEI and LV GLPS, the further decrease of MEEI and LV GLPS in INOCA patients caused by MetS might involve the synergistic injury mechanism. Early diagnosis and treatment of MetS in patients with INOCA are important.

Diagnostic performance of multi-branch coronary angiography-based index of microcirculatory resistance: a novel approach

Background

Wire-based index of microcirculatory resistance (IMR) utilizing pressure wires and thermodilution techniques for the assessment of coronary microcirculatory function, presents challenges for clinical routine use due to its complexity, time-consuming, and costly. This study introduces a novel multi-branch and wire-free method for IMR calculation based on coronary angiography. The diagnostic performance of CAG-IMR is validated within a retrospective single-center investigation.

Methods

In a retrospective single-center study, 139 patients with 201 vessels were evaluated using CAG-IMR for coronary microvascular dysfunction (CMD) detection, utilizing wire-based IMR as the reference standard. CMD was determined based on wire-based IMR ≥25U. CAG-IMR was independently calculated from diagnostic coronary angiography in a blinded fashion, employing the same diagnostic threshold of 25U for CMD identification.

Results

CAG-IMR demonstrated significant correlation (r = 0.84, p < 0.001) and good diagnostic performance AUC = 0.97 (95% CI: 0.95-0.99) compared to wire-based IMR. It exhibited the overall diagnostic accuracy at 95.0% (95% CI: 92.0%-98.0%), alongside high sensitivity (92.7%) and specificity (95.6%). The positive predictive value (PPV) stood at 84.4%, and the negative predictive value (NPV) reached 98.1%.

Conclusions

This study introduces CAG-IMR, a novel, multi-branch and wire-free method for IMR calculation. The indicator demonstrates good diagnostic accuracy and correlation with wire-based IMR in a cohort of 139 patients and 201 vessels, with the potential to enhance clinical CMD assessment.

Computed Tomography Angiography in the Catheterization Laboratory: A Guide Towards Optimizing Coronary Interventions

Cardiac computed tomography (CT) has become an essential tool in the pre-procedural planning and optimization of coronary interventions. Its non-invasive nature allows for the detailed visualization of coronary anatomy, including plaque burden, vessel morphology, and the presence of stenosis, aiding in precise decision making for revascularization strategies. Clinicians can assess not only the extent of coronary artery disease but also the functional significance of lesions using techniques like fractional flow reserve (FFR-CT). By providing comprehensive insights into coronary structure and hemodynamics, cardiac CT helps guide personalized treatment plans, ensuring the more accurate selection of patients for percutaneous coronary interventions or coronary artery bypass grafting and potentially improving patient outcomes.

Coronary microvascular function and atherosclerotic plaque burden in ischaemia and no obstructive coronary arteries: a secondary analysis of the CorMicA trial

BACKGROUND

The relationship between atherosclerosis and endotypes of myocardial ischaemia with no obstructive coronary artery disease (INOCA) is unclear. We investigated potential associations between cumulative atherosclerotic plaque burden quantified using the Gensini score, novel invasive indices of coronary microvascular function (microvascular resistance reserve (MRR); resistive reserve ratio (RRR)) and related INOCA endotypes.

METHODS

Coronary angiography and invasive coronary function tests were simultaneously acquired in the CorMicA cohort. A comprehensive physiological assessment was performed using both a thermodilution-based diagnostic guidewire and intracoronary acetylcholine provocation testing. Angiograms were examined for luminal stenosis in each segment of the SYNTAX coronary model. Cumulative plaque burden was quantified using the Gensini score, which incorporated both the number of diseased coronary segments and stenosis severity. Results were compared with indices of microvascular function and INOCA endotypes. Angiographic analyses were performed blind to coronary physiology findings.

RESULTS

In 151 participants (median age 61 years; 73.5% female) without flow-limiting coronary artery disease, medical history included 41.7% smoking, 63.6% hypertension and 19.2% diabetes mellitus. The left anterior descending artery underwent diagnostic guidewire testing in 85.4%, and 55.0% of participants had abnormal coronary flow reserve (CFR) and/or Index of Microcirculatory Resistance (IMR). The median Gensini score was 6.0 (IQR 2.5-11.0). CFR (p=0.012), MRR (p=0.026) and RRR (p=0.026), but not IMR (p=0.445), were univariably associated with raised Gensini scores. These significant effects persisted in multivariable models controlling for potential confounders. Considering INOCA endotypes, Gensini scores differed among participants with microvascular angina (MVA) (7.0 (2.5-11.0)), vasospastic angina (VSA) (4.5 (2.0-10.0)), mixed MVA/VSA (9.0 (5.0-11.5)) and non-cardiac symptoms (3.5 (1.5-8.0)); Kruskal-Wallis p=0.030.

CONCLUSIONS

Reduced CFR, MRR and RRR, and MVA were associated with increased coronary atherosclerotic plaque burden, as evidenced by higher Gensini scores. These novel findings provide a mechanistic link between INOCA and cardiovascular events, reinforcing the importance of antiatherosclerosis therapy in patients with MVA.

The role of coronary microcirculation in heart failure with preserved ejection fraction: An unceasing odyssey

Heart failure with preserved ejection fraction (HFpEF) represents an entity with complex pathophysiologic pathways, among which coronary microvascular dysfunction (CMD) is believed to be an important orchestrator. Research in the field of CMD has highlighted impaired vasoreactivity, capillary rarefaction, and inflammation as potential mediators of its development. CMD can be diagnosed via several noninvasive methods including transthoracic echocardiography, cardiac magnetic resonance, and positron emission tomography. Moreover, invasive methods such as coronary flow reserve and index of microcirculatory resistance are commonly employed in the assessment of CMD. As far as the association between CMD and HFpEF is concerned, numerous studies have highlighted the coexistence of CMD in the majority of HFpEF patients. Additionally, patients affected by both conditions may be facing an adverse prognosis. Finally, there is limited evidence suggesting a beneficial effect of renin-angiotensin-aldosterone system blockers, ranolazine, and sodium-glucose cotransporter-2 inhibitors in CMD, with further evidence being awaited regarding the impact of other pharmacotherapies such as anti-inflammatory agents.

Prognostic value of transient ischemic dilatation by 13N-ammonia PET MPI for short-term outcomes in patients with non-obstructive CAD

OBJECTIVE

Transient ischaemic dilatation (TID) had incremental diagnostic and prognostic value in obstructive coronary artery disease (CAD), but its clinical significance in patients with non-obstructive CAD remains unknown. We aimed to explore the prognostic value of TID in patients with non-obstructive CAD by 13N-ammonia PET imaging.

METHODS

We retrospectively studied 131 consecutive patients with non-obstructive CAD undergoing one-day rest-stress 13N-ammonia PET myocardial perfusion imaging (MPI). TID was automatically generated using CardIQ Physio software. The receiver operative characteristic (ROC) curve was used to determine the optimal threshold of TID. The follow-up outcome was major adverse cardiac events (MACE), a composite of re-hospitalization for heart failure or unstable angina, late revascularization, non-fatal myocardial infarction, and cardiac death. Cardiac event-free survivals for normal and abnormal TID were compared using Kaplan-Meier plots and log-rank tests.

RESULTS

During a median follow-up of 42.08 ± 17.67 months, 22 (16.7%) patients occurred MACE. The optimal cut-off value of TID was 1.03 based on MACE. Our preliminary outcome analysis suggests that TID-abnormal subjects had a lower overall survival probability. Furthermore, our multivariate analysis reveals abnormal TID was the only independent predictor for MACE in non-obstructive CAD. In the subgroup analysis, an abnormal TID was an independent predictor for MACE in patients with abnormal perfusion patterns.

CONCLUSION

Among patients with non-obstructive CAD, PET-derived TID ≥ 1.03 may identify those with a high risk of subsequent MACE independently. It was also an independent risk factor for poor prognosis in patients with abnormal perfusion.

The Clinical Approach to Angina in Women

Women presenting with angina are more likely to have cardiac chest pain accompanied more frequently by associated symptoms like abdominal pain and lightheadedness. The evaluation of women with suspected coronary disease can be complex because many have microvascular dysfunction, coronary vasospasm, and altered coagulation that require specific testing protocols beyond the conventional stress testing and a coronary angiogram. Therefore, terms such as angina, ischemia, and myocardial infarction with no obstructive coronary disease have been introduced in recent years. More studies are required to elaborate guidelines on the diagnosis and management of these entities.