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

Novel diagnostic approaches and management of coronary microvascular dysfunction

The mechanism underlying ischaemic heart disease (IHD) has been primarily attributed to obstructive coronary artery disease (CAD). However, non-obstructive coronary arteries are identified in >50% of patients undergoing elective coronary angiography, recently leading to growing interest in the investigation and management of angina/ischaemia with non-obstructive coronary arteries (ANOCA/INOCA). INOCA is an umbrella term encompassing a multiple spectrum of possible pathogenetic entities, including coronary vasomotor disorders which consist of two major endotypes: coronary microvascular dysfunction (CMD) and vasospastic angina. Both conditions can coexist and be associated with concomitant obstructive CAD. Particularly, CMD refers to myocardial ischaemia due to reduced vasodilatory capacity of coronary microcirculation secondary to structural remodelling or impaired resting microvascular tone (functional) or a combination of both. CMD is not a benign condition and is more prevalent in women presenting with chronic coronary syndrome compared to men. In this setting, an impaired coronary flow reserve has been associated with increased risk of major adverse cardiovascular events. ANOCA/INOCA patients also experience impaired quality of life and associated increased healthcare costs. Therefore, research in this scenario has led to better definition, classification, and prognostic stratification based on the underlying pathophysiological mechanisms. The development and validation of non-invasive imaging modalities, invasive coronary vasomotor function testing and angiography-derived indices provide a comprehensive characterisation of CMD. The present narrative review aims to summarise current data relating to the diagnostic approach to CMD and provides details on the sequence that therapeutic management should follow.

Lack of Class I Vasoreactivity Testing for Diagnosing Patients With Coronary Artery Spasm

BACKGROUND

Vasoreactivity testing, such as intracoronary acetylcholine (ACh) or ergometrine (EM), is defined as Class I for the diagnosis of patients with vasospastic angina (VSA) according to recommendations from the Coronary Vasomotion Disorders International Study (COVADIS) group and guidelines from the Japanese Circulation Society (JCS).

HYPOTHESIS

Although vasoreactivity testing is a clinically useful tool, it carries some risks and limitations in diagnosing coronary artery spasm.

METHODS

Previous reports on vasoreactivity testing for diagnosing the presence of coronary spasm are summarized from the perspective of Class I.

RESULTS

There are several problems such as reproducibility, underestimation, overestimation, and inconclusive/nonspecific results associated with daily spasm. Because provoked spasm caused by intracoronary ACh is not always similar to that caused by intracoronary EM, possibly due to different mediators, supplementary use of these vasoreactivity tests is necessary for cardiologists to diagnose VSA when a provoked spasm is not revealed by each vasoactive agent.

CONCLUSIONS

Cardiologists should understand the imperfection of these vasoreactivity tests when diagnosing patients with VSA.

Prognostic Value of Coronary Angiography-Derived Index of Microcirculatory Resistance in Non-ST-Segment Elevation Myocardial Infarction Patients

BACKGROUND

The index of microcirculatory resistance is a reliable measure for evaluating coronary microvasculature, but its prognostic value in patients with non-ST-segment elevation myocardial infarction (NSTEMI) remains unclear.

OBJECTIVES

This study aimed to evaluate the prognostic impact of postpercutaneous coronary intervention (PCI) angiography-derived index of microcirculatory resistance (angio-IMR) in patients with NSTEMI.

METHODS

The culprit vessel's angio-IMR was measured after PCI in 2,212 NSTEMI patients at 3 sites. The primary endpoint was 2-year major adverse cardiac events (MACEs), defined as a composite of cardiac death, readmission for heart failure, myocardial reinfarction, and target vessel revascularization.

RESULTS

The mean post-PCI angio-IMR was 20.63 ± 4.17 in NSTEMI patients. A total of 206 patients were categorized as the high post-PCI angio-IMR group according to maximally selected log-rank statistics. Patients with angio-IMR >25 showed a higher rate of MACEs than those with angio-IMR ≤25 (32.52% vs 9.37%; P < 0.001). Post-PCI angio-IMR >25 was an independent predictor of MACEs (HR: 4.230; 95% CI: 3.151-5.679; P < 0.001) and showed incremental prognostic value compared with conventional risk factors (AUC: 0.774 vs 0.716; P < 0.001; net reclassification index: 0.317; P < 0.001; integrated discrimination improvement: 0.075; P < 0.001).

CONCLUSIONS

In patients undergoing PCI for NSTEMI, an increased post-PCI angio-IMR is associated with a higher risk of MACEs. The addition of post-PCI angio-IMR into conventional risk factors significantly improves the ability to reclassify patients and estimate the risk of MACEs. (Angiograph-Derived Index of Microcirculatory Resistance in Patients With Acute Myocardial Infarction; NCT05696379).

The role of myocardial blood volume in the pathophysiology of angina with non-obstructed coronary arteries: The MICORDIS study

BACKGROUND

Angina with Non-Obstructed Coronary Arteries (ANOCA) involves abnormal vasomotor responses. While reduced coronary flow is an established contributor to myocardial hypoxia, myocardial blood volume (MBV) independently regulates myocardial oxygen uptake but its role in ANOCA remains unclear.

OBJECTIVES

We hypothesized that reduced MBV contributes to ANOCA, and associates with insulin resistance in ANOCA.

METHODS

MBV in ANOCA patients was compared to age- and sex-matched healthy controls. ANOCA patients underwent coronary angiography with invasive coronary function testing (CFT) to identify vasospasm and coronary microvascular dysfunction. In all subjects MBV was quantified at baseline, during hyperinsulinemia and during dobutamine-induced stress using myocardial contrast echocardiography (MCE). The hyperinsulinemic-euglycemic clamp was used to assess insulin resistance.

RESULTS

Twenty-eight ANOCA patients (21% men, 56.8 ± 8.6 years) and 28 healthy controls (21% men, 56.5 ± 7.0 years) were included. During CFT 11% of patients showed epicardial vasospasm, 39% microvascular vasospasm, 25% coronary microvascular dysfunction, and 11% of patients had a negative CFT. ANOCA patients had significant lower insulin-sensitivity (p < 0.01). During MCE, ANOCA patients showed a significantly lower MBV at baseline (0.388 vs 0.438 mL/mL, p = 0.04), during hyperinsulinemia (0.395 vs 0.447 mL/mL, p = 0.02), and during dobutamine-induced stress (0.401 vs 0.476 mL/mL, p = 0.030).

CONCLUSIONS

In ANOCA patients MBV is diminished at baseline, during hyperinsulinemia and dobutamine-induced stress in the absence of differences in microvascular recruitment. These findings support the presence of capillary rarefaction in ANOCA patients. ANOCA patients showed metabolic insulin resistance, but insulin did not acutely alter myocardial perfusion.

Exceptionally rare MINOCA: a case of acute myocardial infarction following surgery for Stanford type A aortic dissection

BACKGROUND

Aortic dissection is a severe cardiovascular condition associated with high mortality rates, particularly in cases of Stanford type A aortic dissection (TAAD). Myocardial infarction with non-obstructive coronary arteries (MINOCA) following surgery for TAAD is rare but potentially fatal.

CASE PRESENTATION

A 69-year-old woman presented with sudden chest pain and was diagnosed with acute TAAD. Emergency surgery was performed, during which complications arose, including significant hemodynamic instability. Despite efforts to manage the patient's condition postoperatively, she developed hemodynamic instability and myocardial infarction, leading to cardiogenic shock. MINOCA was diagnosed based on clinical presentation, echocardiographic findings, and coronary angiography ruling out significant stenosis or occlusion. The patient's condition deteriorated despite aggressive treatment, ultimately resulting in death.

CONCLUSION

MINOCA following surgery for TAAD is a rare but serious complication. Vigilant postoperative monitoring and timely intervention are essential for identifying and managing acute cardiac dysfunction in these patients. Further research is required to improve outcomes in this challenging clinical scenario.

Optimizing Management of Stable Angina: A Patient-Centered Approach Integrating Revascularization, Medical Therapy, and Lifestyle Interventions

Angina pectoris may arise from obstructive coronary artery disease (CAD) or in the absence of significant CAD (ischemia with nonobstructed coronary arteries [INOCA]). Therapeutic strategies for patients with angina and obstructive CAD focus on reducing cardiovascular events and relieving symptoms, whereas in INOCA the focus shifts toward managing functional alterations of the coronary circulation. In obstructive CAD, coronary revascularization might improve angina status, although a significant percentage of patients present angina persistence or recurrence, suggesting the presence of functional mechanisms along with epicardial CAD. In patients with INOCA, performing a precise endotype diagnosis is crucial to allow a tailored therapy targeted toward the specific pathogenic mechanism. In this expert opinion paper, we review the evidence for the management of angina, highlighting the complementary role of coronary revascularization, optimal medical therapy, and lifestyle interventions and underscoring the importance of a personalized approach that targets the underlying pathobiology.

Efficacy of BAY 60-2770, a Soluble Guanylate Cyclase Activator, for Coronary Spasm in Animal Models

Ischemia with non-obstructive coronary arteries (INOCA), caused by coronary artery spasm, has gained increasing attention owing to the poor quality of life of impacted patients. Therapeutic options to address INOCA remain limited, and developing new therapeutic agents is desirable. Here, we examined whether soluble guanylate cyclase (sGC) activators could be beneficial in preventing coronary spasms. In organ chamber experiments with isolated canine coronary arteries, prostaglandin F2 α -induced, endothelin-1-induced, 5-hydroxytryptamine-induced, and potassium chloride-induced contractions were suppressed by the sGC activator BAY 60-2770 (0.1, 1, and 10 nM). In isolated pig coronary arteries, BAY 60-2770 (0.1, 1, and 10 nM) could prolong the cycle length of phasic contractions induced by 3,4-diaminopyridine, as well as lower the peak and bottom tension of the contraction in a concentration-dependent manner. Additionally, BAY 60-2770 (1 pM-0.1 µM) evoked a concentration-related relaxation to a greater extent in small (first diagonal branch) coronary arteries than in large (left anterior descending) coronary arteries. In vasopressin-induced angina model rats, pretreatment with BAY 60-2770 (3 µg/kg) suppressed electrocardiogram S-wave depression induced by arginine vasopressin without affecting changes in mean blood pressure and heart rate. These findings suggest that BAY 60-2770 could be valuable in preventing both large and small coronary spasms. Therefore, sGC activators could represent a novel and efficacious therapeutic option for INOCA. SIGNIFICANCE STATEMENT: The soluble guanylate cyclase (sGC) activator BAY 60-2770 exerted antispastic effects on the coronary arteries in animal vasospasm models as proof-of-concept studies. These data can help to support potential clinical development with sGC activators, suitable for human use in patients with vasospastic angina.

Delayed ventricular septal rupture complicated with ventricular aneurysm in a case of myocardial infarction with non-obstructive coronary arteries

BACKGROUND

Myocardial infarction with non-obstructive coronary arteries (MINOCA) is a rare cause of heart attack, which may not receive sufficient attention from patients during post-discharge treatment, especially among those with normal coronary angiography results.

CASE PRESENTATION

We present the case of a 65-year-old woman who was readmitted to the hospital with ventricular septal rupture (VSR) complicated by ventricular aneurysm, occurring 2 weeks after myocardial infarction. During the initial admission, coronary angiography revealed normal coronary arteries, leading to a diagnosis of MINOCA. Epicardial coronary vasospasm or coronary embolism was considered as potential causes; however, the patient did not adhere to standardized treatment upon initial discharge. The delayed VSR led to a decline in cardiac function but did not result in severe hemodynamic impairment. Following correction of heart failure with medications, the patient underwent percutaneous VSR repair 19 days after diagnosis and was discharged with a favorable recovery.

CONCLUSIONS

The occurrence of delayed VSR complicated with ventricular aneurysm in patients with MINOCA is rare, highlighting the possibility of serious complications in MINOCA cases. Both cardioprotective therapies and cause-targeted therapies are essential in the management of patients with MINOCA.

Objective Ischemia, Subjective Angina, and Psychological Distress in Angina With No Obstructive Coronary Disease

BACKGROUND

Angina with no obstructive coronary disease (ANOCA) and ischemia with no obstructive coronary disease, prevalent yet underrecognized conditions, mostly affect women. Previous studies rarely distinguished between them. We aimed to compare the prevalence of objective ischemia through various examinations in women with ANOCA and assess the impact of objective and subjective ischemia on their mental health.

METHODS AND RESULTS

A total of 84 eligible women with ANOCA and 42 controls underwent mental stress, pharmacological stress, exercise stress, and Holter testing. Objective evidence of myocardial ischemia was assessed by positron emission tomography-computed tomography and ECG, and subjective symptoms were graded using the Canadian Cardiovascular Society scale (CCS). Psychological assessments were conducted using 6 scales. Among 84 women with ANOCA, 37 (44%) received a diagnosis of ischemia with no obstructive coronary disease following mental stress testing, 20 (28.6%) through pharmacological stress testing, 14 (21.2%) via exercise stress testing, and 24 (32.9%) from Holter. Mental stress-induced myocardial ischemia was more prevalent (P<0.05). Among 54 patients with ANOCA who completed all tests, 30% showed no ischemia, and only 1 (1.9%) showed ischemia in all tests. In addition, patients with ANOCA had higher psychological scores than controls (P<0.01). No significant differences was observed in psychological scores between ANOCA with positive and negative ischemia test results (P>0.05). However, ANOCA with milder angina (CCS I) exhibited higher scores across the Hospital Anxiety and Depression Scale, State-Trait Anxiety Inventory, Perceived Stress Scale, and Posttraumatic Stress Disorder Checklist-Civilian Version and a higher prevalence of Type D personality traits (P<0.05).

CONCLUSIONS

In patients with ANOCA, the positive rate of myocardial ischemia exhibits variability among several noninvasive tests. A worsened psychological state is more closely linked to milder angina symptoms than to ischemia performance, highlighting the importance of focusing on symptom management in their psychological care.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT03982901.

Prognostic Implications of Resistive Reserve Ratio in Patients With Nonobstructive Coronary Artery Disease With Myocardial Bridging

BACKGROUND

Myocardial bridging (MB) is accompanied by the dynamic extravascular compression of epicardial coronary arteries, leading to intracoronary hemodynamic disturbance with abnormal coronary flow profiles. We aimed to evaluate the prognostic implications of resistive reserve ratio (RRR), a composite measure of flow and pressure parameters that represents the vasodilatory capacity of the coronary arteries, in patients with angina with nonobstructive coronary artery disease (ANOCA) and MB, in comparison with coronary flow reserve (CFR).

METHODS AND RESULTS

In this retrospective cohort study, we included patients with ANOCA who underwent coronary reactivity testing, where MB was identified by transient constriction in coronary artery segments between systole and diastole. Abnormal CFR and RRR were defined as <2.5 and <2.62, respectively. Major adverse cardiac events, including cardiovascular death, stroke, myocardial infarction, heart failure, and late revascularization, served as outcomes. Among 1251 patients with ANOCA, 191 (15.3%) had MB. The prevalence of abnormal CFR or RRR was not significantly different between patients with and without MB (P=0.144 and P=0.398, respectively). Over a median follow-up time of 6.9 years, abnormal RRR predicted major adverse cardiac events in patients with MB (hazard ratio [HR], 4.38 [95% CI, 1.71-11.21]; P=0.002) and without MB (HR, 1.91 [95% CI, 1.38-2.64]; P<0.001). Abnormal CFR predicted major adverse cardiac events in patients without MB (HR, 2.15 [95% CI, 1.54-3.00]; P<0.001), whereas it was not predictive of major adverse cardiac events in patients with MB (HR, 2.29 [95% CI, 0.93-5.65]; P=0.073).

CONCLUSIONS

In patients with ANOCA and MB, impaired RRR was superior to impaired CFR in distinguishing patients at a higher risk of future adverse events, suggesting that RRR may serve as a risk stratification tool in patients with MB and ANOCA.

Is the peripheral microcirculation a window into the human coronary microvasculature?

An increasing body of evidence suggests a pivotal role for the microvasculature in the development of cardiovascular disease. A dysfunctional coronary microvascular network, specifically within endothelial cells-the inner most cell layer of vessels-is considered a strong, independent risk factor for future major adverse cardiac events. However, challenges exist with evaluating this critical vascular bed, as many of the currently available techniques are highly invasive and cost prohibitive. The more easily accessible peripheral microcirculation has surfaced as a potential surrogate in which to study mechanisms of coronary microvascular dysfunction and likewise may be used to predict poor cardiovascular outcomes. In this review, we critically evaluate a variety of prognostic, physiological, and mechanistic studies in humans to answer whether the peripheral microcirculation can add insight into coronary microvascular health. A conceptual framework is proposed that the health of the endothelium specifically may link the coronary and peripheral microvascular beds. This is supported by evidence showing a correlation between human coronary and peripheral endothelial function in vivo. Although not a replacement for investigating and understanding coronary microvascular function, the microvascular endothelium from the periphery responds similarly to (patho)physiological stress and may be leveraged to explore potential therapeutic pathways to mitigate stress-induced damage.

Female-specific risk variables: From innocent bystanders to key players in cardiovascular risk prediction

There is an increasing interest among professionals in cardiovascular medicine in women-specific risk variables related to gynecologic conditions over the life span. Although adverse lifestyle factors, hypertension, dyslipidemia and insulin resistance are recognized as the most important risk factors in older women, there is still uncertainty over how to account for other risk variables. For instance, migraine from puberty onwards, chronic inflammatory conditions and mental stress affect cardiovascular risk in women. As prevention should start as early in life as possible, appropriate risk estimation in women at middle age is crucial. In case of doubt, a coronary artery calcium score with a computed tomography scan at a radiology department can be helpful to discriminate between low and high risk for an individual. This may also pave the way for safe menopausal hormone therapy if needed. In this paper we summarize the current status of women-specific and other relevant risk variables from the perspective of the cardiologist.

Do electrocardiographic changes induced during intracoronary vasospasm provocation testing reflect those during spontaneous angina episodes in patients with vasospastic angina?: a case series

Background

According to the Coronary Vasomotor Disorders International Study (COVADIS) group, the ECG criteria supporting the diagnosis of vasospastic angina (VSA) in spontaneous episodes or induced during intracoronary spasm testing are similar. However, it remains elusive whether acetylcholine-induced ECG changes during epicardial spasms reflect ECG changes that occur during the height of a spontaneous episode.

Case summary

We present four patients diagnosed with VSA during intracoronary spasm testing, of whom the ECG characteristics during spasm testing and a spontaneous angina episode are described. All patients have >90% coronary epicardial vasoconstriction in one or more vessels during acetylcholine provocation. ECGs at the height of a spontaneous episode and during acetylcholine-induced coronary spasm are found to be different in three out of four patients.

Discussion

In patients with VSA, the ECG at the height of a spontaneous episode and during acetylcholine-induced coronary artery spasm may differ substantially. In patients with symptoms suspicious of VSA, every effort should be undertaken to obtain ECGs during the height of a spontaneous episode of angina pectoris and there should be a low threshold to perform intracoronary function testing.

Impact of coronary microvascular dysfunction in heart failure with preserved ejection fraction: a meta-analysis

AIMS

Several mechanisms have been identified in the aetiopathogenesis of heart failure with preserved ejection fraction (HFpEF). Among these, coronary microvascular dysfunction (CMD) may play a key pathophysiological role. We performed a systematic review and meta-analysis to investigate the prevalence, echocardiographic correlates, and prognostic implications of CMD in patients with HFpEF.

METHODS AND RESULTS

A systematic search for articles up to 1 May 2023 was performed. The primary aim was to assess the prevalence of CMD. Secondary aims were to compare key echocardiographic parameters (E/e' ratio, left atrial volume index [LAVi], and left ventricular mass index [LVMi]), clinical outcomes [death and hospitalization for heart failure (HF)], and prevalence of atrial fibrillation (AF) between patients with and without CMD. Meta-regressions according to baseline patient characteristics and study features were performed to explore potential heterogeneity sources. We identified 14 observational studies, enrolling 1138 patients with HFpEF. The overall prevalence of CMD was 58%. Compared with patients without CMD, patients with HFpEF and CMD had larger LAVi [mean difference (MD) 3.85 confidence interval (CI) 1.19-6.5, P < 0.01)], higher E/e' ratio (MD 2.76 CI 1.54-3.97; P < 0.01), higher prevalence of AF (odds ratio 1.61 CI 1.04-2.48, P = 0.03) and higher risk of death or hospitalization for HF [hazard ratio 3.19, CI 1.04-9.57, P = 0.04].

CONCLUSIONS

CMD is present in little more than half of the patients with HFpEF and is associated with echocardiographic evidence of more severe diastolic dysfunction and a higher prevalence of AF, doubling the risk of death or HF hospitalization.

Beyond Coronary Artery Disease: Assessing the Microcirculation

Ischemic heart disease (IHD) affects more than 20 million adults in the United States. Although classically attributed to atherosclerosis of the epicardial coronary arteries, nearly half of patients with stable angina and IHD who undergo invasive coronary angiography do not have obstructive epicardial coronary artery disease. Ischemia with nonobstructive coronary arteries is frequently caused by microvascular angina with underlying coronary microvascular dysfunction (CMD). Greater understanding the pathophysiology, diagnosis, and treatment of CMD holds promise to improve clinical outcomes of patients with ischemic heart disease.

Psychological burden in patients with angina and unobstructed coronary arteries-underestimated, underexplored, undertreated

Patients with angina and unobstructed coronary arteries (ANOCA) are frequently encountered in clinical practice. These cases represent a diagnostic and therapeutic challenge and are often characterized by a long patient journey until a diagnosis of coronary vasomotor disorders is established. Moreover, the unsatisfactory management of such patients leads to insecurity, ongoing symptoms, and psychological sequelae such as anxiety or depression. Currently, the psychological burden in patients with ANOCA is underestimated, underexplored, and undertreated. This review gives a new perspective on the pathophysiology of coronary vasomotor disorders including psychological risk factors and calls for comprehensive care by interdisciplinary ANOCA clinics.

Heterogeneity of coronary vascular function and myocardial oxygenation in women with angina and non-obstructive coronary artery disease

AIMS

Women with angina and non-obstructive coronary artery disease (ANOCA) have a heightened risk for cardiovascular events, and the pathophysiology for ischaemic symptoms may be related to alterations in microvascular structure and function. We examined the use of breathing-enhanced oxygenation-sensitive cardiac magnetic resonance imaging (OS-CMR) using vasoactive breathing manoeuvres to assess myocardial oxygenation in women with ANOCA.

METHODS AND RESULTS

We recruited women (aged 40-65 years) from two sites in Canada who presented to healthcare with persistent retrosternal chest pain and found to have ANOCA, or without a history of cardiovascular disease. All participants were scanned using a clinical 3T MRI scanner, and OS-CMR images were acquired over a breath hold following paced hyperventilation to measure global and regional measurements of heterogeneity. Fifty-four women with ANOCA (age: 55 ± 6.2 years) and 48 healthy controls (age: 51.2 ± 4.8 years) were recruited. There was no significant difference in volume, function, mass, or global myocardial oxygenation between the two groups [mean %Δ in signal intensity (SI): 4.9 (±7.3) vs. 4.5 (±10.1), P = 0.82]. Women with ANOCA had higher regional variations in myocardial oxygenation in circumferential [median %Δ in SI: 5.1 (2.0-7.6) vs. 2.2 (1.4-3.5), P = 0.0004] and longitudinal directions [median %Δ in SI: 11.4 (5.4-16.7) vs. 6.0 (3.0-7.0), P = 0.001], which remained present in a multivariate model.

CONCLUSION

Heterogeneous myocardial oxygenation may explain ischaemic symptoms without any associated epicardial obstructive coronary artery disease. Regional variations in myocardial oxygenation on OS-CMR could serve as an important diagnostic marker for microvascular dysfunction in women with ANOCA.

Ischemia with non-obstructive coronary artery (INOCA): Non-invasive versus invasive techniques for diagnosis and the role of #FullPhysiology

Ischemia with non-obstructive coronary arteries (INOCA) is an increasingly recognized entity. It encompasses different pathophysiological subtypes (i.e., endotypes), including coronary microvascular dysfunction (CMD), vasospastic angina (VSA) and mixed entities resulting from the variable combination of both. Diagnosing INOCA and precisely characterizing the endotype allows for accurate medical treatment and has proven prognostic implications. A breadth of diagnostic technique is available, ranging from non-invasive approaches to invasive coronary angiography adjuvated by functional assessment and provocative tests. This review summarizes the strength and limitations of these methodologies and provides the rationale for the routine referral for invasive angiography and functional assessment in this subset of patients.

Myocardial Ischemia: Differentiating between Epicardial Coronary Artery Atherosclerosis, Microvascular Dysfunction and Vasospasm in the Catheterization Laboratory

Ischemic heart disease is currently the most common cause of mortality and morbidity worldwide. Although myocardial ischemia is classically determined by epicardial coronary atherosclerosis, up to 40% of patients referred for coronary angiography have no obstructive coronary artery disease (CAD). Ischemia with non-obstructive coronary artery disease (INOCA) has typically been underestimated in the past because, until recently, its prognostic significance was not completely clear. This review aims to highlight differences and patterns in myocardial ischemia caused by epicardial obstructive CAD, coronary microvascular dysfunction (CMD) or vasomotor abnormalities and to elucidate the state of the art in correctly diagnosing these different patterns.

Hemodialysis-induced Myocardial Stunning with No Obstructive Coronary Artery Disease: Pathophysiological Significance of Coronary Microvascular Dysfunction

Hemodialysis (HD)-induced myocardial stunning, characterized by transient left ventricular systolic dysfunction during HD, has been reported to be common and associated with a poor prognosis. However, the pathophysiology is not fully understood. We herein report a case of HD-induced myocardial stunning without obstructive coronary artery disease complicated by coronary microvascular dysfunction (CMD), suggesting that CMD plays a crucial role in the pathophysiology of this disease.

Factors Contributing to Coronary Microvascular Dysfunction in Patients with Angina and Non-Obstructive Coronary Artery Disease

BACKGROUND

Coronary microvascular dysfunction (CMD), characterised by a reduced coronary flow reserve (CFR) or an increased index of microcirculatory resistance (IMR), has received considerable attention as a cause of chest pain in recent years. However, the risks and causes of CMD remain unclear; therefore, effective treatment strategies have not yet been established. Heart failure or coronary artery disease (CAD) is a risk factor for CMD, with a higher prevalence among women. However, the other contributing factors remain unclear. In this study, we assessed the risk in patients with angina and non-obstructive coronary artery disease (ANOCA), excluding those with heart failure or organic stenosis of the coronary arteries. Furthermore, we analysed whether the risk of CMD differed according to component factors and sex.

METHODS

This study included 84 patients with ANOCA (36 men and 48 women; mean age, 63 years) who underwent coronary angiography and functional testing (CFT). The CFT included a spasm provocation test (SPT), followed by a coronary microvascular function test (CMVF). In the SPT, patients were mainly provoked by acetylcholine (ACh), and coronary spasm was defined as >90% transient coronary artery constriction on coronary angiography, accompanied by chest pain or ischaemic changes on electrocardiography. In 15 patients (18%) with negative ACh provocation, ergonovine maleate (EM) was administered as an additional provocative drug. In the CMVF, a pressure wire was inserted into the left anterior descending coronary artery using intravenous adenosine triphosphate, and the CFR and IMR were measured using previously described methods. A CFR < 2.0 or IMR ≥ 25 was indicative of CMD. The correlations between various laboratory indices and CMD and its components were investigated, and logistic regression analysis was performed, focusing on factors where p < 0.05.

RESULTS

Of the 84 patients, a CFR < 2.0 was found in 22 (26%) and an IMR ≥ 25 in 40 (48%) patients, with CMD identified in 46 (55%) patients. CMD was correlated with smoking (p = 0.020) and the use of EM (p = 0.020). The factors that correlated with a CFR < 2.0 included the echocardiograph index E/e' (p = 0.013), which showed a weak but positive correlation with the CFR (r = 0.268, p = 0.013). Conversely, the factors correlated with an IMR ≥ 25 included RAS inhibitor usage (p = 0.018) and smoking (p = 0.042). Assessment of the risk of CMD according to sex revealed that smoking (p = 0.036) was the only factor associated with CMD in men, whereas the left ventricular mass index (p = 0.010) and low glycated haemoglobin levels (p = 0.012) were associated with CMD in women.

CONCLUSIONS

Our results indicated that smoking status and EM use were associated with CMD. The risk of CMD differed between the two CMD components and sex. Although these factors should be considered when treating CMD, smoking cessation remains important. In addition, CMD assessment should be performed carefully when EM is used after ACh provocation. Further validation of our findings using prospective studies and large registries is warranted.

Myocardial Bridging as a Trigger in Angina With No Obstructive Coronary Artery Disease

We present 2 patients with angina with no obstructive coronary artery disease and concomitant myocardial bridging. Despite maximal tolerated pharmacotherapy, symptoms remained. Invasive anatomical and hemodynamic assessment identified myocardial bridging as a contributing cause of angina. Following heart team discussion, both patients underwent successful coronary artery unroofing of the left anterior descending artery.

Innervation of the coronary arteries and its role in controlling microvascular resistance

The coronary circulation plays a crucial role in balancing myocardial perfusion and oxygen demand to prevent myocardial ischemia. Extravascular compressive forces, coronary perfusion pressure, and microvascular resistance are involved to regulate coronary blood flow throughout the cardiac cycle. Autoregulation of the coronary blood flow through dynamic adjustment of microvascular resistance is maintained by complex interactions among mechanical, endothelial, metabolic, neural, and hormonal mechanisms. This review focuses on the neural mechanism. Anatomy and physiology of the coronary arterial innervation have been extensively investigated using animal models. However, findings in the animal heart have limited applicability to the human heart as cardiac innervation is generally highly variable among species. So far, limited data are available on the human coronary artery innervation, rendering multiple questions unresolved. Recently, the clinical entity of ischemia with non-obstructive coronary arteries has been proposed, characterized by microvascular dysfunction involving abnormal vasoconstriction and impaired vasodilation. Thus, measurement of microvascular resistance has become a standard diagnostic for patients without significant stenosis in the epicardial coronary arteries. Neural mechanism is likely to play a pivotal role, supported by the efficacy of cardiac sympathetic denervation to control symptoms in patients with angina. Therefore, understanding the coronary artery innervation and control of microvascular resistance of the human heart is increasingly important for cardiologists for diagnosis and to select appropriate therapeutic options. Advancement in this field can lead to innovations in diagnostic and therapeutic approaches for coronary artery diseases.

A systematic review for the evidence of recommendations and guidelines in hybrid nuclear cardiovascular imaging

OBJECTIVES

This study aimed to evaluate the level of evidence of expert recommendations and guidelines for clinical indications and procedurals in hybrid nuclear cardiovascular imaging.

METHODS

From inception to August 2023, a PubMed literature analysis of the latest version of guidelines for clinical hybrid cardiovascular imaging techniques including SPECT(/CT), PET(/CT), and PET(/MRI) was performed in two categories: (1) for clinical indications for all-in primary diagnosis; subgroup in prognosis and therapy evaluation; and for (2) imaging procedurals. We surveyed to what degree these followed a standard methodology to collect the data and provide levels of evidence, and for which topic systematic review evidence was executed.

RESULTS

A total of 76 guidelines, published between 2013 and 2023, were included. The evidence of guidelines was based on systematic reviews in 7.9% of cases, non-systematic reviews in 47.4% of cases, a mix of systematic and non-systematic reviews in 19.7%, and 25% of guidelines did not report any evidence. Search strategy was reported in 36.8% of cases. Strengths of recommendation were clearly reported in 25% of guidelines. The notion of external review was explicitly reported in 23.7% of cases. Finally, the support of a methodologist was reported in 11.8% of the included guidelines.

CONCLUSION

The use of evidence procedures for developing for evidence-based cardiovascular hybrid imaging recommendations and guidelines is currently suboptimal, highlighting the need for more standardized methodological procedures.

Stratified medicine for acute and chronic coronary syndromes: A patient-tailored approach

The traditional approach to management of cardiovascular disease relies on grouping clinical presentations with common signs and symptoms into pre-specified disease pathways, all uniformly treated according to evidence-based guidelines ("one-size-fits-all"). The goal of precision medicine is to provide the right treatment to the right patients at the right time, combining data from time honoured sources (e.g., history, physical examination, imaging, laboratory) and those provided by multi-omics technologies. In patients with ischemic heart disease, biomarkers and intravascular assessment can be used to identify endotypes with different pathophysiology who may benefit from distinct treatments. This review discusses strategies for the application of stratified management to patients with acute and chronic coronary syndromes.

Ischaemia with no obstructive coronary arteries: a review with focus on the Asian population

ABSTRACT

Ischaemia with no obstructive coronary arteries (INOCA) has been a diagnostic and therapeutic challenge for decades. Several studies have demonstrated that INOCA is associated with an increased risk of death, adverse cardiovascular events, poor quality of life and high healthcare cost. Although there is increasing recognition of this entity in the Western population, in the Asian population, INOCA remains elusive and its prevalence uncertain. Despite its prognostic significance, diagnosis of INOCA is often delayed. In this review, we identified the multiple barriers to its diagnosis and management, and proposed strategies to overcome them.

Protocol Variation in Functional Coronary Angiography Among Patients With Suspected Angina With Non-Obstructive Coronary Arteries: A Nationwide Snapshot of Current Practice Within Australia and New Zealand

BACKGROUND

Functional coronary angiography (FCA) for endotype characterisation (vasospastic angina [VSA], coronary microvascular disease [CMD], or mixed) is recommended among patients with angina with non-obstructive coronary arteries. Whilst clear diagnostic criteria for VSA and CMD exist, there is no standardised FCA protocol. Variations in testing protocol may limit the widespread uptake of testing, generalisability of results, and expansion of collaborative research. At present, there are no data describing protocol variation across an entire geographic region. Therefore, we aimed to capture current practice variations in the approach to FCA to improve access and standardisation for diagnosis of coronary vasomotor disorders in Australia and New Zealand.

METHOD

Between July 2022 and July 2023, we conducted a national survey across all centres in Australia and New Zealand with an active FCA program. The survey captured attitudes towards FCA and protocols used for diagnosis of coronary vasomotor disorders at 33 hospitals across Australia and New Zealand.

RESULTS

Survey responses were received from 39 clinicians from 33 centres, with representation from centres within all Australian states and territories and both North and South Islands of New Zealand. A total of 21 centres were identified as having an active FCA program. In general, respondents agreed that comprehensive physiology testing helped inform clinical management. Barriers to program expansion included cost, additional catheter laboratory time, and the absence of an agreed-upon national protocol. Across the clinical sites, there were significant variations in testing protocol, including the technique used (Doppler vs thermodilution), order of testing (hyperaemia resistance indices first vs vasomotor function testing first), rate and dose of acetylcholine administration, routine use of temporary pacing wire, and routine single vs multivessel testing. Overall, testing was performed relatively infrequently, with very little follow-on FCA performed, despite nearly all respondents believing this would be clinically useful.

CONCLUSIONS

This survey demonstrates, for the first time, variations in FCA protocol among testing centres across two entire countries. Furthermore, whilst FCA was deemed clinically important, testing was performed relatively infrequently with little or no follow-on testing. Development and adoption of a standardised national FCA protocol may help improve patient access to testing and facilitate further collaborative research within Australia and New Zealand.

New avenues for the assessment of stable ischemic heart disease

Myocardial ischemia is a complex condition which may result from epicardial and/or microvascular causes involving functional and structural mechanisms. These mechanisms may overlap in a given patient illustrating the difficulties for appropriate management. Assessment of myocardial ischemia can be performed using noninvasive and invasive tools. However, despite living in the era of individualized precision medicine, these tools are not yet used in a broader fashion. Emerging noninvasive techniques such as quantitative perfusion cardiac magnetic resonance imaging (CMR) and stress perfusion computed tomography (CT) or photon-counting CT techniques may contribute to new standards in the assessment of stable angina patients. Invasive evaluation of myocardial ischemia should not only focus on hemodynamically relevant epicardial disease but also involve coronary vasomotor function testing (coronary spasm, coronary flow reserve, and microvascular resistance) where appropriate. Optimal patient management will depend on accurate and comprehensive diagnostic evaluation of myocardial ischemia and development of new treatment options in the future.

Multimodality assessment of the coronary microvasculature with TIMI frame count versus perfusion PET highlights coronary changes characteristic of coronary microvascular disease

Background

The diagnosis of coronary microvascular disease (CMVD) remains challenging. Perfusion PET-derived myocardial blood flow (MBF) reserve (MBFR) can quantify CMVD but is not widely available. Thrombolysis in Myocardial Infarction (TIMI) frame count (TFC) is an angiography-based method that has been proposed as a measure of CMVD. Here, we compare TFC and PET-derived MBF measurements to establish the role of TFC in assessing for CMVD. We use coronary modeling to elucidate the relationship between MBFR and TFC and propose TFC thresholds for identifying CMVD.

Methods

In a cohort of 123 individuals (age 58 ± 12.1, 63% women, 41% Caucasian) without obstructive coronary artery disease who had undergone perfusion PET and coronary angiography for clinical indications, we compared TFC and perfusion PET parameters using Pearson correlation (PCC) and linear regression modeling. We used mathematical modeling of the coronary circulation to understand the relationship between these parameters and performed Receiver Operating Curve (ROC) analysis.

Results

We found a significant negative correlation between TFC and MBFR. Sex, race and ethnicity, and nitroglycerin administration impact this relationship. Coronary modeling showed an uncoupling between TFC and flow in epicardial vessels. In ROC analysis, TFC performed well in women (AUC 0.84-0.89) and a moderately in men (AUC 0.68-0.78).

Conclusions

We established an inverse relationship between TFC and PET-derived MBFR, which is affected by patient selection and procedural factors. TFC represents a measure of the volume of the epicardial coronary compartment, which is increased in patients with CMVD, and performs well in identifying women with CMVD.

Transthoracic ultrasound localization microscopy of myocardial vasculature in patients

Myocardial microvasculature and haemodynamics are indicative of potential microvascular diseases for patients with symptoms of coronary heart disease in the absence of obstructive coronary arteries. However, imaging microvascular structure and flow within the myocardium is challenging owing to the small size of the vessels and the constant movement of the patient's heart. Here we show the feasibility of transthoracic ultrasound localization microscopy for imaging myocardial microvasculature and haemodynamics in explanted pig hearts and in patients in vivo. Through a customized data-acquisition and processing pipeline with a cardiac phased-array probe, we leveraged motion correction and tracking to reconstruct the dynamics of microcirculation. For four patients, two of whom had impaired myocardial function, we obtained super-resolution images of myocardial vascular structure and flow using data acquired within a breath hold. Myocardial ultrasound localization microscopy may facilitate the understanding of myocardial microcirculation and the management of patients with cardiac microvascular diseases.

Coronary computed tomography angiography for clinical practice

Coronary artery disease (CAD) is a common condition caused by the accumulation of atherosclerotic plaques. It can be classified into stable CAD or acute coronary syndrome. Coronary computed tomography angiography (CCTA) has a high negative predictive value and is used as the first examination for diagnosing stable CAD, particularly in patients at intermediate-to-high risk. CCTA is also adopted for diagnosing acute coronary syndrome, particularly in patients at low-to-intermediate risk. Myocardial ischemia does not always co-exist with coronary artery stenosis, and the positive predictive value of CCTA for myocardial ischemia is limited. However, CCTA has overcome this limitation with recent technological advancements such as CT perfusion and CT-fractional flow reserve. In addition, CCTA can be used to assess coronary artery plaques. Thus, the indications for CCTA have expanded, leading to an increased demand for radiologists. The CAD reporting and data system (CAD-RADS) 2.0 was recently proposed for standardizing CCTA reporting. This RADS evaluates and categorizes patients based on coronary artery stenosis and the overall amount of coronary artery plaque and links this to patient management. In this review, we aimed to review the major trials and guidelines for CCTA to understand its clinical role. Furthermore, we aimed to introduce the CAD-RADS 2.0 including the assessment of coronary artery stenosis, plaque, and other key findings, and highlight the steps for CCTA reporting. Finally, we aimed to present recent research trends including the perivascular fat attenuation index, artificial intelligence, and the advancements in CT technology.

INOCA: Ischemia in non-obstructive coronary arteries

This article provides a summary of the clinical spectrum of no obstructive coronary arteries. We describe the pathologies, invasive and noninvasive assessment, and management strategies.

Triglyceride-glucose index is associated with myocardial ischemia and poor prognosis in patients with ischemia and no obstructive coronary artery disease

BACKGROUND

Ischemia and no obstructive coronary artery disease (INOCA) is increasingly recognized and associated with poor outcomes. The triglyceride-glucose (TyG) index is a reliable alternative measure of insulin resistance significantly linked to cardiovascular disease and adverse prognosis. We investigated the association between the TyG index and myocardial ischemia and the prognosis in INOCA patients.

METHODS

INOCA patients who underwent both coronary angiography and myocardial perfusion imaging (MPI) were included consecutively. All participants were divided into three groups according to TyG tertiles (T1, T2, and T3). Abnormal MPI for myocardial ischemia in individual coronary territories was defined as summed stress score (SSS) ≥ 4 and summed difference score (SDS) ≥ 2. SSS refers to the sum of all defects in the stress images, and SDS is the difference of the sum of all defects between the rest images and stress images. All patients were followed up for major adverse cardiac events (MACE).

RESULTS

Among 332 INOCA patients, 113 (34.0%) had abnormal MPI. Patients with higher TyG index had a higher rate of abnormal MPI (25.5% vs. 32.4% vs. 44.1%; p = 0.012). Multivariate logistic analysis showed that a high TyG index was significantly correlated with abnormal MPI in INOCA patients (OR, 1.901; 95% CI, 1.045-3.458; P = 0.035). During the median 35 months of follow-up, 83 (25%) MACE were recorded, and a higher incidence of MACE was observed in the T3 group (T3 vs. T2 vs. T1: 36.9% vs. 21.6% vs. 16.4%, respectively; p = 0.001). In multivariate Cox regression analysis, the T3 group was significantly associated with the risk of MACE compared to the T1 group (HR, 2.338; 95% CI 1.253-4.364, P = 0.008).

CONCLUSION

This study indicates for the first time that the TyG index is significantly associated with myocardial ischemia and poor prognosis among INOCA patients.

Causes of Death in Patients Asking for Polyclinic Care for Coronary Heart Disease

AIM

Retrospective analysis of the underlying causes for death of patients who did and did not seek outpatient medical care (OPMC) for ischemic heart disease (IHD), and discussion of a possibility for using administrative anonymized but individualized databases for analysis.

MATERIAL AND METHODS

The electronic database of the Central Administration of the Civil Registry Office of the Moscow Region (Unified State Register of the Civil Registry Office of the Moscow Region), including medical death certificates (MDC) for 2021, was used to select all cases of fatal outcomes with the disease codes of the International Classification of Diseases, Tenth Revision (ICD-10) (codes of external causes, injuries, poisonings excluded) that were indicated as the primary cause of death (PCD). Personalized data of the deceased were combined with data from electronic medical records of patients who sought OPMC at institutions of the Moscow Region within up to 2 years before death. In addition to IHD, the following PCD codes were taken into account: malignant tumors, COVID-19, diabetes mellitus, cerebrovascular diseases, hypertension, chronic obstructive pulmonary disease, alcohol-associated diseases, and, as examples of unspecified PCD, old age and unspecified encephalopathy.Results In total, among those who died from diseases, the proportion of those who died from IHD was 18.9%; for another 8.4%, IHD was indicated as a comorbid disease in Part II of the MDC. Among those who sought OPMC for IHD, the IHD proportion indicated as PCD was 27.5%, and among those who did not seek OPMC 17.4% (p <0.0001). Those who died from IHD and who had sought OPMC were older (mean age, 75.59 ± 10.94 years) than those who died from IHD and had not sought OMPM (mean age, 73.96 ± 10.94 years; p < 0.0001). The frequency of myocardial infarction as PCD among those who had and had not sought OPMC was the same (12%), chronic forms of IHD were 83.9% and 79.7%, the frequencies of "unspecified" acute forms of IHD (codes I24.8-9) were 4.1% and 8.3%, respectively. The proportion of deaths from COVID-19 was the highest (21.7% and 24.3%, respectively), from malignant neoplasms 11.6% and 12.7%, respectively, and from unspecified encephalopathy 10.6% and 10.7%, respectively.

CONCLUSION

Only 25% of patients who had sought OPMC for IHD died from IHD, otherwise the causes of death were the same as for patients who had not sought OPMC for IHD. Analysis of administrative databases allows identifying disparities in the PCD structure and to direct the efforts of specialists to reconciling the criteria for death from various forms of IHD.

WNT Signaling Cascade Proteins and LRP6 in the Formation of Various Types of Coronary Lesions in Patients With Coronary Artery Disease

AIM

Assessment of WNT1, WNT3a, and LRP6 concentrations in patients with ischemic heart disease (IHD) and obstructive and non-obstructive coronary artery (CA) disease.

MATERIAL AND METHODS

This cross-sectional observational study included 50 IHD patients (verified by coronary angiography, CAG), of which 25 (50%) were men, mean age 64.9±8.1 years; 20 patients had non-obstructive CA disease (stenosis <50%), and 30 patients had hemodynamically significant stenosis. Concentrations of WNT1, WNT3a and LRP6 were measured in all patients.

RESULTS

The concentrations of WNT1 and WNT3a proteins were significantly higher in patients with IHD and obstructive CA disease (p < 0.001), while the concentration of LRP6 was higher in the group with non-obstructive CA disease (p = 0.016). Data analysis of the group with obstructive CA disease showed a moderate correlation between WNT1 and LRP6 (ρ=0.374; p=0.042). Correlation analysis of all groups of patients with CA disease revealed a moderate association between the concentrations of WNT1 and uric acid (ρ=0.416; p=0.007). Regression analysis showed that risk factors for the development of IHD, such as increased body mass index, age, smoking, dyslipidemia, and hypertension, did not significantly influence the type of CA disease in IHD patients. According to ROC analysis, the obstructive form of IHD was predicted by a WNT3a concentration higher than 0.155 ng/ml and a LRP6 concentration lower than 12.94 ng/ml.

CONCLUSION

IHD patients with non-obstructive CA disease had the greatest increase in LRP6, while patients with obstructive CA disease had significantly higher concentrations of the canonical WNT cascade proteins, WNT1 and WNT3a. According to the ROC analysis, a WNT3a concentration >0.155 ng/ml can serve as a predictor for the presence of hemodynamically significant CA stenosis in IHD patients (sensitivity 96.7%; specificity 70%), whereas a LRP6 concentration >12.94 ng/ml can predict the development of non-obstructive CA disease (sensitivity 76.7%; specificity 65%).

GSEA analysis identifies potential drug targets and their interaction networks in coronary microcirculation disorders

Coronary microcirculation dysfunction (CMD) is one of the main causes of cardiovascular disease. Traditional treatment methods lack specificity, making it difficult to fully consider the differences in patient conditions and achieve effective treatment and intervention. The complexity and diversity of CMD require more standardized diagnosis and treatment plans to clarify the best treatment strategy and long-term outcomes. The existing treatment measures mainly focus on symptom management, including medication treatment, lifestyle intervention, and psychological therapy. However, the efficacy of these methods is not consistent for all patients, and the long-term efficacy is not yet clear. GSEA is a bioinformatics method used to interpret gene expression data, particularly for identifying the enrichment of predefined gene sets in gene expression data. In order to achieve personalized treatment and improve the quality and effectiveness of interventions, this article combined GSEA (Gene Set Enrichment Analysis) technology to conduct in-depth research on potential drug targets and their interaction networks in coronary microcirculation dysfunctions. This article first utilized the Coremine medical database, GeneCards, and DrugBank public databases to collect gene data. Then, filtering methods were used to preprocess the data, and GSEA was used to analyze the preprocessed gene expression data to identify and calculate pathways and enrichment scores related to CMD. Finally, protein sequence features were extracted through the calculation of autocorrelation features. To verify the effectiveness of GSEA, this article conducted experimental analysis from four aspects: precision, receiver operating characteristic (ROC) curve, correlation, and potential drug targets, and compared them with Gene Regulatory Networks (GRN) and Random Forest (RF) methods. The results showed that compared to the GRN and RF methods, the average precision of GSEA improved by 0.11. The conclusion indicated that GSEA helped identify and explore potential drug targets and their interaction networks, providing new ideas for personalized quality of CMD.

Adenosine in Interventional Cardiology: Physiopathologic and Pharmacologic Effects in Coronary Artery Disease

This review article focuses on the role of adenosine in coronary artery disease (CAD) diagnosis and treatment. Adenosine, an endogenous purine nucleoside, plays crucial roles in cardiovascular physiology and pathology. Its release and effects, mediated by specific receptors, influence vasomotor function, blood pressure regulation, heart rate, and platelet activity. Adenosine therapeutic effects include treatment of the no-reflow phenomenon and paroxysmal supraventricular tachycardia. The production of adenosine involves complex cellular pathways, with extracellular and intracellular synthesis mechanisms. Adenosine's rapid metabolism underscores its short half-life and physiological turnover. Furthermore, adenosine's involvement in side effects of antiplatelet therapy, particularly ticagrelor and cangrelor, highlights its clinical significance. Moreover, adenosine serves as a valuable tool in CAD diagnosis, aiding stress testing modalities and guiding intracoronary physiological assessments. Its use in assessing epicardial stenosis and microvascular dysfunction is pivotal for treatment decisions. Overall, understanding adenosine's mechanisms and clinical implications is essential for optimizing CAD management strategies, encompassing both therapeutic interventions and diagnostic approaches.

Mental Stress-Induced Myocardial Ischemia Detected by Global Longitudinal Strain and Quantitative Myocardial Contrast Echocardiography in Women With Nonobstructive Coronary Artery Disease

BACKGROUND

The utility of radionuclide myocardial perfusion imaging including positron emission tomography (PET) for diagnosing mental stress-induced myocardial ischemia (MSIMI) is clinically restricted. This study aims to assess the diagnostic performance of novel echocardiographic techniques, including automated strain and quantitative myocardial contrast echocardiography (MCE) with dedicated software and deep neural network model, for MSIMI detection. The secondary objective was to explore the correlation between changes in myocardial blood flow and MSIMI.

METHODS

Seventy-two female patients ages 18 to 75 with angina and nonobstructive coronary artery disease (ANOCA) and 23 healthy controls were prospectively recruited. Both echocardiography with contrast agent and PET imaging were performed during structured mental stress testing. Mental stress-induced myocardial ischemia was defined as a summed difference score ≥3 on PET. Echocardiographic parameters including left ventricular global longitudinal strain, β, and A × β were obtained, and their trends during mental stress testing were observed. ΔGLS was defined as the ratio of difference between global longitudinal strain values at stress and rest to the rest data. β reserve and A×β reserve were respectively calculated.

RESULTS

Thirty-two ANOCA patients (44%) and 1 control (4%) were diagnosed with MSIMI (P < .01). For ANOCA patients with MSIMI, left ventricular GLS, β, and A × β declined to varied extents during mental stress testing compared with those without MSIMI and the controls (P < .05). Bland-Altman plots demonstrated good consistency between β reserve and A × β reserve output by the deep neural network model and iMCE software. Receiver operating characteristic curve analyses showed that ΔGLS, β reserve, and A × β reserve demonstrated favorable ability to predict MSIMI, especially the combination of A × β reserve using iMCE analysis and ΔGLS (area under the curve, 0.94; sensitivity, 83%; specificity, 97%).

CONCLUSIONS

Novel technologies in echocardiography exhibit the potential to be a clinical alternative to cardiac PET for effectively detecting MSIMI. Attenuated myocardial blood flow response during structured mental stress testing was correlated with MSIMI, providing a reasonable explanation for the chest discomfort persisting in ANOCA women.

Relation of Vasoreactivity in the Left and Right Coronary Arteries During Acetylcholine Spasm Provocation Testing

The diagnosis of vasospastic angina (VSA) according to Japanese guidelines involves an initial intracoronary acetylcholine (ACh) provocation test in the left coronary artery (LCA) followed by testing in the right coronary artery (RCA). However, global variations in test protocols often lead to the omission of ACh provocation in the RCA, potentially resulting in the underdiagnosis of VSA. This study assessed the validity of the LCA-only ACh provocation approach for the VSA diagnosis and whether vasoreactivity in the LCA aids in determining further provocation in the RCA. A total of 273 patients who underwent sequential intracoronary ACh provocation testing in the LCA and RCA were included. Patients with a positive ACh provocation test in the LCA were excluded. Relations between vasoreactivity in the LCA and ACh test outcomes (positivity and adverse events) in the RCA were evaluated. In patients with negative ACh test results in the LCA, subsequent ACh testing was positive in the RCA in 23 of 273 (8.4%) patients. In patients with minimal LCA vasoconstriction (<25%), only 3.0% had a positive ACh test in the RCA, whereas the ACh test in the RCA was positive in 13.5% of those with LCA constriction of 25% to 90% (p = 0.002). No major adverse events occurred during ACh testing in the RCA. In conclusion, for the VSA diagnosis, the omission of ACh provocation in the RCA may be clinically acceptable, particularly when vasoconstriction induced by ACh injection was minimal in the LCA. Further studies are needed to define ACh provocation protocols worldwide.

Coronary microvascular dysfunction and atrial reservoir function

BACKGROUND

Coronary microvascular dysfunction (CMD) refers to structural and functional abnormalities of the coronary microcirculation, which may be diagnosed using invasive coronary physiology. CMD is responsible for impaired diastolic cardiac function. It has recently been suggested that left atrial strain (LASr) represents a highly sensitive tool for detecting cardiac diastolic function abnormalities. Accordingly, the aim of this study was to investigate the relationship between CMD and LASr.

METHODS

Consecutively enrolled patients with non-obstructed coronary arteries (NOCA) underwent CMD and LASr evaluation by invasive thermodilution and noninvasive echocardiography, respectively.

RESULTS

Forty-two (42) patients were included, out of which 26 presented with CMD. There were no significant differences between CMD-positive and negative patients in terms of clinical and echocardiographic characteristics. LASr was significantly reduced in patients with CMD (24.6% ± 6.1 vs. 30.3 ± 7.8%, p = 0.01). A moderate correlation was observed between coronary flow reserve and LAsr (r = 0.47, p = 0.002). A multivariate logistic regression analysis demonstrated that CMD was independently associated with LASr (OR = 0.88, 95%CI 0.78-0.99.135, p = 0.04). A LASr cut-off of 25.5% enabled an optimal classification of patients with or without CMD.

CONCLUSION

Patients with NOCA and CMD had a significantly reduced LASr compared with patients without CMD, suggesting the early impairment of diastolic function in these patients.

Exploring the interplay between coronary microvascular dysfunction and mental health

BACKGROUND

The intricate relationship between mental health disorders, notably anxiety and depression, and chest pain associated with non-obstructive coronary artery disease has become a focus of investigation.

METHODS

This study from the Coronary Microvascular Disease Registry (CMDR) evaluated the association of mental health disorders and coronary microvascular dysfunction (CMD) among patients with angina with no obstructive coronary artery disease (ANOCA) who had undergone comprehensive invasive physiological testing for CMD. Clinical data regarding baseline characteristics, comorbidities, and noninvasive cardiac testing were obtained from chart review. The primary outcome of interest was the potential relationship between mental health diagnoses and the presence of CMD.

RESULTS

Of patients included in the CMDR, 27 % (41/152) had at least one documented mental health disorder diagnosis (International Classification of Diseases, Tenth Revision codes) and CMD. There was no difference in mental health diagnosis prevalence between CMD-positive and CMD-negative patients (21.1 % vs. 28.9 %, p = 0.34). The most common mental health diagnoses were depression (15.8 %) and anxiety (15.8 %). Furthermore, 46.3 % (19/41) of patients with mental health disorders were prescribed psychiatric medications, with the most common being benzodiazepines (26.8 %).

CONCLUSION

Patients with chest pain not due to CMD did not have an increased prevalence of mental health disorders compared with patients with ANOCA due to CMD, challenging the notion of a psychosomatic component in the pathogenesis of ANOCA.

Ejection Fraction-Related Differences of Baseline Characteristics and Outcomes in Troponin-Positive Patients without Obstructive Coronary Artery Disease

Background: The development and course of myocardial infarction with non-obstructive coronary artery (MINOCA) disease is still not fully understood. In this study, we aimed to examine the baseline characteristics of in-hospital outcomes and long-term outcomes of a cohort of troponin-positive patients without obstructive coronary artery disease based on different left ventricular ejection fractions (LVEFs). Methods and results: We included a cohort of 254 patients (mean age: 64 (50.8-75.3) years, 120 females) with suspected myocardial infarction and no obstructive coronary artery disease (MINOCA) in our institutional database between 2010 and 2021. Among these patients, 170 had LVEF ≥ 50% (84 females, 49.4%), 31 patients had LVEF 40-49% (15 females, 48.4%), and 53 patients had LVEF < 40% (20 females, 37.7%). The mean age in the LVEF ≥ 50% group was 61.5 (48-73) years, in the LVEF 40-49% group was 67 (57-78) years, and in the LVEF < 40% group was 68 (56-75.5) years (p = 0.05). The mean troponin value was highest in the LVEF < 40% group, at 3.8 (1.7-4.6) µg/L, and lowest in the LVEF ≥ 50% group, at 1.1 (0.5-2.1) µg/L (p = 0.05). Creatine Phosphokinase (CK) levels were highest in the LVEF ≥ 50% group (156 (89.5-256)) and lowest in the LVEF 40-49% group (127 (73-256)) (p < 0.05), while the mean BNP value was lowest in the LVEF ≥ 50% group (98 (48-278) pg/mL) and highest in the <40% group (793 (238.3-2247.5) pg/mL) (p = 0.001). Adverse in-hospital cardiovascular events were highest in the LVEF < 40% group compared to the LVEF 40-49% group and the LVEF ≥ 50% group (56% vs. 55% vs. 27%; p < 0.001). Over a follow-up period of 6.2 ± 3.1 years, the all-cause mortality was higher in the LVEF < 40% group compared to the LVEF 40-49% group and the LVEF ≥ 50% group. Among the different factors, LVEF < 40% and LVEF 40-49% were associated with an increased risk of in-hospital cardiovascular events in the multivariable Cox regression analysis. Conclusions: LVEF has different impacts on in-hospital cardiovascular events in this cohort. Furthermore, LVEF influences long-term all-cause mortality.

Clinical Significance of Coronary Arterial Dominance: A Review of the Literature

Coronary dominance describes the anatomic variation of coronary arterial supply, notably as it relates to perfusion of the inferior cardiac territories. Differences in the development and outcome in select disease states between coronary dominance patterns are increasingly recognized. In particular, observational studies have identified higher prevalence of poor outcomes in left coronary dominance in the setting of ischemic, conduction, and valvular disease. In this qualitative literature review, we summarize anatomic, physiologic, and clinical implications of differences in coronary dominance to highlight current understanding and gaps in the literature that should warrant further studies.

Usability of myocardial work parameters in demonstrating myocardial involvement in INOCA patients

BACKGROUND

Myocardial work (MW) is a novel echocardiographic modality, which has been shown to have diagnostic and prognostic values in patients with cardiovascular diseases, patients with obstructive coronary artery disease, in particular. However, only a handful of studies have examined the MW analysis in ischemia with nonobstructive coronary artery (INOCA) disease. This study, therefore, aimed to detect the early left ventricular involvement in INOCA patients diagnosed by an invasive coronary angiography performing the MW analysis.

METHODS

This study included a total of 119 patients with nonobstructive coronary artery disease diagnosed by invasive coronary angiography, who were checked for prior ischemia tests performing myocardial perfusion scintigraphy. Out of these 119 patients, 49 patients developed ischemia (i.e., ischemic group) diagnosed using cardiac single-photon emission computed tomography, whereas 70 patients did not (i.e., nonischemic group). The subjects were divided into three groups based on the global MW tertiles. The groups were compared in terms of the conventional, longitudinal strain, and MW findings by conducting echocardiographic examinations.

RESULTS

The study subjects were divided into three groups based on the global constrictive work (GCW) value. The three groups were not statistically different in terms of the mean age of the patients (53.0 ± 12 vs. 52.4 ± 13.3 vs. 52.1 ± 12.3; p = 0.96). Furthermore, the three groups were not statistically different regarding the gender, height, weight, and laboratory parameters of the patients except albumin. There was no statistically difference among the tertiles of GCW groups in the measurements of cardiac chambers, LA diameter, interventricular septum, E wave, and A wave. Also, there was no statistical difference in tissue Doppler recordings. The parameters associated with MW were examined, three groups were not statistically different in terms of the global waste work (GWW) (116 ± 92, 122 ± 73, 135 ± 62, p = 0.52, respectively). In contrast, the three groups were different regarding the Global work index (GWI) (1716 ± 300, 1999 ± 130, 2253 ± 195, p < 0.001, respectively), GCW (1888 ± 206, 2298 ± 75, 2614 ± 155, p < 0.001, respectively), and Global work efficiency parameters (92.8 ± 3.6, 94.4 ± 3.2, 95.1 ± 1.8 p = 0.004, respectively).

CONCLUSION

It was concluded that the MW parameters GCW and GWI may have been used for predicting INOCA in patients.

Impact of renal denervation on patients with coronary microvascular dysfunction: study rationale and design

AIMS

Long-standing hypertension may cause an impairment in microvascular coronary circulation, which is involved in many different cardiac conditions. Renal sympathetic denervation (RDN) has been successfully proven as a valuable therapeutic choice for patients with resistant hypertension; moreover, the procedure looks promising in other settings, such as heart failure and atrial fibrillation, given its ability to downregulate the sympathetic nervous system, which is a recognized driver in these conditions as well as in microvascular dysfunction progression. The aim of this study is to explore the effect of RDN on coronary physiology in patients with ascertained coronary microvascular dysfunction and resistant hypertension.

METHODS

This is a multicenter, prospective, nonrandomized, open-label, interventional study. Consecutive patients with resistant hypertension, nonobstructive coronary artery disease (NOCAD) and documented microvascular dysfunction will be enrolled. Patients will undergo RDN by Spyral Symplicity 3 (Medtronic Inc, Minneapolis, Minnesota, USA) and reassessment of coronary microvascular function 6 months after the procedure. Primary endpoint will be the difference in the index of microcirculatory resistance.

CONCLUSION

The IMPRESSION study seeks to evaluate if there is any pleiotropic effect of the RDN procedure that results in modulation of microvascular function; if observed, this would be the first evidence showing RDN as a valuable therapy to revert hypertension-related microvascular dysfunction.