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 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.

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.

Discordant Diagnosis of Coronary Microvascular Dysfunction by Microvascular Resistance Reserve: Transthoracic Doppler Echocardiography vs Bolus Thermodilution Method

BACKGROUND

Epicardial stenosis and coronary microvascular dysfunction (CMD) may coexist in patients with chronic coronary syndrome (CCS). Microvascular resistance reserve (MRR) has been demonstrated to be a valid cross-modality metric using continuous saline infusion thermodilution and intracoronary Doppler flow velocity methods. This study aimed to investigate the prevalence and diagnostic concordance of CMD defined by MRR using two methods-stress transthoracic Doppler echocardiography (S-TDE) and the invasive bolus thermodilution method (B-Thermo)-in patients with functionally significant epicardial stenosis.

METHODS

We retrospectively investigated 204 left anterior descending artery (LAD) territories in CCS. All patients underwent physiological assessment using a pressure-temperature wire and S-TDE before elective fractional flow reserve (FFR)-guided percutaneous coronary intervention. The concordance rate was evaluated using κ values.

RESULTS

In the final analysis, the median age was 72 years, and 72.5% of patients were male. The median FFR value was 0.69. MRRS-TDE and MRRB-Thermo were similar (3.41 vs. 3.48, P=0.877), whereas only a weak, albeit significant relationship was observed between these two metrics (r=0.167, P=0.017). CMD was diagnosed in 20.6% and 32.8% of patients using S-TDE and B-Thermo, respectively, when a cutoff MRR value of 2.7 was applied. The concordance rate of CMD diagnosis between the two methods was low (κ=0.079).

CONCLUSIONS

MRRS-TDE and MRRB-Thermo showed a very weak correlation in the LAD territory with functionally significant stenosis in patients with CCS. The prevalence of CMD diagnosed using MRRS-TDE and MRRB-Thermo was not comparable, and the diagnostic concordance of CMD using these two methods was very low.

[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.

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.

Incremental prognostic value of 18F-fluorodeoxyglucose myocardial ischemic memory imaging for major adverse cardiovascular events in patients with suspected unstable angina

BACKGROUND

The additional prognostic value of 18F-flurodeoxyglucose positron emission tomography (18F-FDG PET) myocardial ischemic memory imaging for patients with suspected unstable angina (UA) is not well established. This study aimed to determine whether 18F-FDG PET imaging provides incremental prognostic information for predicting major adverse cardiac events (MACEs) compared to clinical risk factors, Global Registry of Acute Coronary Events (GRACE) score, and coronary artery calcium score (CACS) in patients with suspected UA.

METHODS

In this post hoc analysis of a prospective study, 265 patients suspected with UA (62.3% male, mean age: 65.0±9.4 years) were enrolled. 18F-FDG positivity was defined as focal or focal on diffuse uptake patterns. MACEs included cardiovascular death, acute myocardial infarction, heart failure, rehospitalization for UA, and stroke. Multivariable Cox regression was used to identify predictors of MACEs, and the incremental prognostic value of 18F-FDG PET imaging was assessed using the Concordance Index (C-index), net reclassification improvement (NRI), and integrated discrimination improvement (IDI).

RESULTS

Over a median follow-up of 25 months, 51 patients (19.2%) experienced MACEs. 18F-FDG positivity (hazard ratio [HR]=3.220, 95% confidence interval [CI]: 1.630-6.360, P<.001), as well as 18F-FDG standardized uptake ratio (HR=1.330, 95% CI: 1.131-1.564, P=.0006) and Extent (HR=1.045, 95% CI: 1.028-1.062, P<.0001), were independent predictors of MACE. The addition of 18F-FDG PET imaging significantly improved risk stratification beyond clinical factors, the GRACE score, and CACS, with improved C-index (.769 vs .688, P=.045), NRI (.324, P=.020), and IDI (.055, P=.027).

CONCLUSION

18F-FDG PET myocardial ischemic memory imaging significantly improves prognostic assessment for patients with suspected UA, providing valuable additional risk stratification beyond clinical risk factors, GRACE score, and CACS.

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.

Zibotentan in Microvascular Angina: A Randomized, Placebo-Controlled, Crossover Trial

BACKGROUND

Microvascular angina is associated with dysregulation of the endothelin system and impairments in myocardial blood flow, exercise capacity, and health-related quality of life. The G allele of the noncoding single nucleotide polymorphism RS9349379 enhances expression of the endothelin-1 gene (EDN1) in human vascular cells, potentially increasing circulating concentrations of Endothelin-1 (ET-1). Whether zibotentan, an oral ET-A receptor selective antagonist, is efficacious and safe for the treatment of microvascular angina is unknown.

METHODS

Patients with microvascular angina were enrolled in this double-blind, placebo-controlled, sequential crossover trial of zibotentan (10 mg daily for 12 weeks). The trial population was enriched to ensure a G allele frequency of 50% for the RS9349379 single nucleotide polymorphism. Participants and investigators were blinded to genotype. The primary outcome was treadmill exercise duration (seconds) using the Bruce protocol. The primary analysis estimated the mean within-participant difference in exercise duration after treatment with zibotentan versus placebo.

RESULTS

A total of 118 participants (mean±SD; years of age 63.5 [9.2]; 71 [60.2%] females; 25 [21.2%] with diabetes) were randomized. Among 103 participants with complete data, the mean exercise duration with zibotentan treatment compared with placebo was not different (between-treatment difference, -4.26 seconds [95% CI, -19.60 to 11.06] P=0.5871). Secondary outcomes showed no improvement with zibotentan. Zibotentan reduced blood pressure and increased plasma concentrations of ET-1. Adverse events were more common with zibotentan (60.2%) compared with placebo (14.4%; P<0.001).

CONCLUSIONS

Among patients with microvascular angina, short-term treatment with a relatively high dose (10 mg daily) of zibotentan was not beneficial. Target-related adverse effects were common.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT04097314.

Feasibility and Improved Diagnostic Yield of Intracoronary Adenosine to Assess Microvascular Dysfunction With Bolus Thermodilution

BACKGROUND

Bolus thermodilution and intravenous adenosine are established methods for coronary microcirculatory assessment. Yet, its adoption remains low, partly due to procedural time and patient discomfort associated with intravenous adenosine. We investigated differences between intracoronary and intravenous adenosine using bolus thermodilution in terms of microcirculatory indices, procedural time, and side effects associated with adenosine in patients with myocardial ischemia and nonobstructive coronary arteries.

METHODS AND RESULTS

In this prospective, observational study, 102 patients with suspected myocardial ischemia and nonobstructive coronary arteries underwent measurements of mean transit time, coronary flow reserve, index of microcirculatory resistance, procedure time and patient tolerability with low-dose intracoronary adenosine, high-dose intracoronary adenosine (HDIC), and intravenous adenosine. HDIC induced greater hyperemia compared with low-dose intracoronary IC adenosine and intravenous adenosine with a shorter hyperemic mean transit time, P<0.0001. Coronary flow reserve was higher and index of microcirculatory resistance lowest with HDIC, compared with low-dose intracoronary IC adenosine and intravenous adenosine, P<0.05. Low coronary flow reserve was downgraded from 21% with intravenous adenosine to 10% with HDIC adenosine (P=0.031); high index of microcirculatory resistance was downgraded from 23% with intravenous adenosine to 14% with HDIC (P=0.098). Intracoronary adenosine was associated with lower procedural times (P<0.0001). More patients experienced chest pain with intravenous adenosine (P<0.01) and the chest pain intensity was higher compared with intracoronary adenosine (P<0.0001).

CONCLUSIONS

In patients with suspected myocardial ischemia and nonobstructive coronary arteries undergoing coronary microcirculatory assessment with bolus thermodilution, the use of HDIC compared with intravenous adenosine was associated with enhanced induction of hyperemia. The use of intracoronary adenosine allowed for a shorter procedure time and was better tolerated.

REGISTRATION+

URL: clinicaltrials.gov; Unique Identifier: NCT04827498.

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.

Diagnostic Yield of Comprehensive Coronary Function Testing in Patients with Angina and Unobstructed Coronary Arteries: Endotype Characterisation and Clinical Implications

Background

Coronary functional disorders (CFD) are significant contributors to angina with non-obstructed coronary arteries (ANOCA). Various endotypes, such as epicardial or microvascular spasm and/or coronary microvascular dysfunction (CMD), have been identified. Previous studies have shown a high prevalence of CFD in ANOCA cases, but often lacked comprehensive coronary functional testing (CFT), which ideally includes coronary spasm provocation testing and CMD assessment. This study aims to investigate the prevalence of CFD and to characterise endotypes in ANOCA patients using comprehensive CFT.

Methods

A total of 89 consecutive ANOCA patients (mean age 64, 69% women) who underwent comprehensive CFT were enrolled. CFT comprised acetylcholine (ACh) spasm provocation testing and assessment of coronary flow reserve (CFR) and hyperaemic microvascular resistance using Doppler technique.

Results

CFT identified at least one coronary vasomotion disorder in 91% of patients with ANOCA. Among them, microvascular spasm was the most common endotype (61%), followed by CMD (43%). Only 9% of patients had isolated CMD with the remaining CMD patients also showing coronary spasm. Low CFR was mainly associated with high resting coronary flow rather than impaired hyperaemic flow (R -0.60, p<0.0001). Additionally, 48% of patients with microvascular spasm exhibited moderate to severe coronary tortuosity.

Conclusion

CFT provides a high diagnostic yield of CFD in ANOCA patients. Coronary spasm, particularly microvascular spasm, is the most frequent endotype. Patients with isolated CMD are rare, highlighting the importance of spasm testing in the ANOCA population.

Assessment of Coronary Microvascular Dysfunction by Angiography-Based Index of Microcirculatory Resistance: An Indirect Meta-Analysis

INTRODUCTION

There is a lack of consensus on diagnosing coronary microvascular dysfunction (CMD) using the angiography-based index of microcirculatory resistance (Angio-IMR) due to the absence of evidence. This study aimed to explore the efficacy of Angio-IMR in diagnosing CMD.

METHODS

A systematic search was conducted in PubMed, Embase, Scopus, and the Cochrane Library for studies primarily focusing on Angio-IMR diagnosing CMD, using IMR as the gold standard. The primary results were pooled sensitivity, specificity, and the area under the curve (AUC).

RESULTS

A total of 15 studies involving 2,202 individuals and 2,330 vessels were included in our study, Angio-IMR demonstrated high performance in predicting IMR with overall pooled sensitivity and specificity of 0.84 (95% confidence interval (CI): 0.81-0.87) and 0.87 (95% CI: 0.83-0.99), respectively, and AUC = 0.91 (95% CI: 0.89-0.94). This indicates that Angio-IMR has good diagnostic characteristics. Subgroup analysis by indirect meta-analysis showed higher sensitivity in the rest state. However, there is no significant difference in sensitivity and specificity between the hyperemic and rest states when using the AccuIMR system. Furthermore, sensitivity and specificity were more pronounced in the group without coronary pressure monitoring compared to the group with monitoring.

CONCLUSION

Angio-IMR is an alternative tool to identify CMD.

Effects of statins in patients with coronary artery spasm: A nationwide population-based study

Controversies regarding the benefits of statin treatment on clinical outcomes in coronary artery spasm (CAS) without obstructive coronary artery disease (CAD) persist due to limited data. In this retrospective nationwide population-based cohort study from the Taiwan National Health Insurance Research Database during the period 2000-2012, the matched cohorts consisted of 12,000 patients with CAS. After propensity score matching with 1:1 ratio, 2216 patients were eligible for outcome analysis in either statin or nonstatin group, with the mean follow-up duration of 4.8 and 4.6 years, respectively. Statin users versus nonusers had a significantly reduced risk of major adverse cardiovascular events (MACEs) (6.7% vs. 9.5%, hazard ratio [HR] 0.68; 95% confidence interval [CI] 0.55-0.84) and all-cause mortality (6.0% vs. 7.6%; HR 0.77; 95% CI 0.61-0.96). While the results of MACEs were mainly contributed by cardiovascular death (1.9% vs. 3.2%; HR 0.56; 95% CI 0.38-0.83) and ischemic stroke (3.8% vs. 5.4%; subdistribution HR 0.69; 95% CI 0.52-0.91), they were primarily driven by reductions in ischemic but not hemorrhagic stroke. The benefit of statins was significantly pronounced in patients with hypertension and diabetes. Nevertheless, the effect on MACEs was consistent irrespective of age, sex, dyslipidemia, and mental disorder. Statins significantly reduced the risk of MACEs and all-cause mortality in CAS patients. The benefit of statin therapy in reducing MACEs appeared to be linear, with greater risk reduction with higher doses and longer duration without upper threshold, reflecting the dose-dependent relationship of statins with MACEs in CAS patients.

Age-related structural remodelling of the coronary circulation

BACKGROUND

While it is broadly accepted that ageing is associated with impairment of coronary microvascular function, little is known about the underlying mechanisms.

AIMS

We investigated age-related changes in coronary microvascular structure in patients with stable angina without epicardial coronary stenoses.

METHODS

In an analysis of the IDEAL registry, a total of 165 vessels without coronary stenosis were interrogated with combined pressure/Doppler guidewires. We calculated diastolic microvascular conductance (DMVC) and backward expansion wave (BEW), and compared them between age tertiles. We calculated the prevalence of CMD, defined by reduced coronary flow reserve (CFR), and the prevalence of low BEW and low DMVC in each group.

RESULTS

The three study groups were defined as having 37-53, 54-66, and 67-77 years of age, respectively. Oldest (3rd tertile) patients showed lower hyperemic flow velocity (46.7 ± 14.4 vs. 45.1 ± 12.4 vs. 38.4 ± 11.5 cm s-1, p = 0.019), lower DMVC (1.90 ± 0.71 vs. 1.44 ± 0.56 vs. 1.37 ± 0.67 cm s-1 mmHg-1, p < 0.001) and lower BEW intensity (5.9 [2.9-8.4] vs. 4.8 [2.9-6.8] vs. 4.4 [3.4-6.3] × 106 W m-2 s-1, p = 0.094). Older age was independently associated with lower BEW intensity (B: -0.10, 95% confidence interval [CI]: -0.17 to -0.09, p = 0.021) and DMVC (B: -0.25 95% CI: -0.45 to -0.09, p = 0.027). In patients with CFR < 2.5, the prevalence of BEW intensity and DMVC below the 25th percentile increased with age (25.0% vs. 52.0% vs. 72.7%, p = 0.010).

CONCLUSIONS

Ageing is independently associated with structural microcirculatory remodeling that is reflected in BEW intensity and DMVC measurements, and with an increased prevalence of structural CMD. These results are important to understand non-obstructive mechanisms of myocardial ischemia in the elderly.

Coronary microvascular dysfunction beyond the spectrum of chronic coronary syndromes

The prevalence of coronary microvascular dysfunction (CMD) beyond the spectrum of chronic coronary syndromes (CCS) is non-negligible, pertaining to pathophysiological and therapeutical implications. Thanks to the availability of accurate and safe non-invasive technique, CMD can be identified as a key player in heart failure, cardiomyopathies, Takotsubo syndrome, aortic stenosis. While CMD is widely recognized as a cause of myocardial ischemia leading to a worse prognosis even in the absence of obstructive coronary artery disease, the characterization of CMD patterns beyond CCS might provide valuable insights on the underlying disease progression, being potentially a "red flag" of adverse cardiac remodeling and a major determinant of response to therapy and outcomes. In this review, we aimed to provide an overview of the latest evidence on the prevalence, mechanistic and prognostic implications of CMD beyond the spectrum of CCS (i.e. heart failure, cardiomyopathies, Takotsubo syndrome, aortic stenosis).

Absolute coronary blood flow across different endotypes of ANOCA

BACKGROUND

Intracoronary continuous thermodilution is a novel technique to quantify absolute true coronary flow and microvascular resistance. However, few data are available in patients with angina with non-obstructive coronary arteries (ANOCA).

AIMS

This study aimed to investigate the diagnostic potential of hyperaemic absolute coronary flow (Qmax) and absolute microvascular resistance (Rμ,hyper) among different ANOCA endotypes, and to determine the correlation between continuous - and bolus - thermodilution indexes.

METHODS

A total of 222 patients were scheduled for clinically indicated coronary function testing (CFT), of whom 120 patients were included in this analysis. These patients underwent CFT including acetylcholine (ACh) provocation testing and microvascular function assessment using both bolus and continuous thermodilution.

RESULTS

CFT was negative (CFT-) in 32 (26.7%) patients. Endothelium-dependent dysfunction (ACh+) was present in 63 (52.5%) patients, and coronary microvascular dysfunction (CMD) identified at bolus thermodilution (CMD+) was present in 62 (51.7%) patients. Patients with a positive CFT (CFT+) showed significantly lower Qmax and higher Rμ,hyper values as compared to CFT-. Qmax was significantly lower in CMD+ versus CMD- patients (0.174 vs 0.222 L/min; p=0.04) but did not differ in patients with or without a positive ACh test (0.198 vs 0.219 L/min; p=0.86).

CONCLUSIONS

The prevalence of a CFT+ is high in a selected ANOCA population. In our study, Qmax and Rμ,hyper were associated with a positive CFT. Qmax was associated with the presence of microvascular dysfunction but not with a positive acetylcholine test. The novel continuous thermodilution method can provide further insights into ANOCA endotypes.

Mechanism of Coronary Microcirculation Obstruction after Acute Myocardial Infarction and Cardioprotective Strategies

ST-segment elevation myocardial infarction patients are best treated with emergency percutaneous coronary intervention (PCI), while coronary microvascular dysfunction and obstruction (CMVO) are indicated by the absence or slowing of antegrade epicardial flow on angiography, resulting in suboptimal myocardial perfusion despite the lack of mechanical vascular obstruction. CMVO occurs in up to half of patients who undergo PCI for the first time and is associated with poor outcomes. This review summarizes the complex mechanisms leading to CMVO and elaborates on the changes observed at the organism, tissue, organ, cellular, and molecular levels. It also describes the current diagnostic methods and comprehensive treatment methods for CMVO.

The ANOCA/INOCA Dilemma Considering the 2024 ESC Guidelines on Chronic Coronary Syndromes

Cardiovascular disease remains a significant cause of morbidity and mortality worldwide, and its manifestations continue to pose a challenge in clinical practice [...].

Non-Invasive Assessment of Coronary Microvascular Dysfunction Using Vascular Deformation-Based Flow Estimation

OBJECTIVE

Non-invasive computation of the index of microcirculatory resistance from coronary computed tomography angiography (CTA), referred to as IMR[Formula: see text], is a promising approach for quantitative assessment of coronary microvascular dysfunction (CMD). However, the computation of IMR[Formula: see text] remains an important unresolved problem due to its high requirement for the accuracy of coronary blood flow. Existing CTA-based methods for estimating coronary blood flow rely on physiological assumption models to indirectly identify, which leads to inadequate personalization of total and vessel-specific flow.

METHODS

To overcome this challenge, we propose a vascular deformation-based flow estimation (VDFE) model to directly estimate coronary blood flow for reliable IMR[Formula: see text] computation. Specifically, we extract the vascular deformation of each vascular segment from multi-phase CTA. The concept of inverse problem solving is applied to implicitly derive coronary blood flow based on the physical constraint relationship between blood flow and vascular deformation. The vascular deformation constraints imposed on each segment within the vascular structure ensure sufficient individualization of coronary blood flow.

RESULTS

Experimental studies on 106 vessels collected from 89 subjects demonstrate the validity of our VDFE, achieving an IMR[Formula: see text] accuracy of 82.08 %. The coronary blood flow estimated by VDFE has better reliability than the other four existing methods.

CONCLUSION

Our proposed VDFE is an effective approach to non-invasively compute IMR[Formula: see text] with excellent diagnostic performance.

SIGNIFICANCE

The VDFE has the potential to serve as a safe, effective, and cost-effective clinical tool for guiding CMD clinical treatment and assessing prognosis.

A recurrent typical angina pectoris without any finding in coronary angiography: Microvascular angina

Key Clinical Message

Microvascular angina (MVA) can present with recurrent chest pain and normal coronary angiography. Recognizing MVA is crucial as it significantly impacts patient morbidity and mortality. Early diagnosis and management with antianginal medications are essential for improving outcomes and quality of life.

Abstract

Cardiovascular diseases are still the main cause of death in many parts of the world. Chest pain and dyspnea are always concerning due to the implications of cardiovascular disease. However, in patients with the involvement of the small coronary vessels (Microvascular Angina), symptoms might be recurrent and persistent despite the presence of normal coronary vessel evaluations. A 45-year-old man with a 25-year smoking history presented with recurrent chest pain, especially during physical activity, and mild shortness of breath. He was admitted, and a coronary angiography the next day appeared normal. However, a cardiac PET scan revealed the involvement of small coronary vessels not visible on angiography. The Patient was a 45-year-old man who presented with recurrent chest pain, more prominent during physical activity. He also had mild shortness of breath. The patient was admitted, and the next day, he underwent normal coronary angiography. The cardiac positron emission tomography (PET scan) showed the involvement of small coronary vessels that were not obvious on angiography.

Coronary microvascular disease in women: epidemiology, mechanisms, evaluation, and treatment

Coronary microvascular dysfunction (CMD) involves functional or structural abnormalities of the coronary microvasculature resulting in dysregulation of coronary blood flow (CBF) in response to myocardial oxygen demand. This perfusion mismatch causes myocardial ischemia, which manifests in patients as microvascular angina (MVA). CMD can be diagnosed non-invasively via multiple imaging techniques or invasively using coronary function testing (CFT), which assists in determining the specific mechanisms involving endothelium-independent and dependent epicardial and microcirculation domains. Unlike traditional coronary artery disease (CAD), CMD can often occur in patients without obstructive atherosclerotic epicardial disease, which can make the diagnosis of CMD difficult. Moreover, MVA due to CMD is more prevalent in women and carries increased risk of future cardiovascular events. Successful treatment of symptomatic CMD is often patient-specific risk factor and endotype targeted. This article aims to review newly identified mechanisms and novel treatment strategies for managing CMD, and outline sex-specific differences in the presentation and pathophysiology of the disease.

Comparative study of myocardial perfusion and coronary flow velocity reserve derived from adenosine triphosphate stress myocardial contrast echocardiography in coronary lesions with no/mild stenosis

Background

Qualitative myocardial perfusion (QMP) derived from myocardial contrast echocardiography reflects the capillary flow, while coronary flow velocity reserve from Doppler spectrum (D-CFVR) of the left anterior descending coronary artery (LAD) is used to assess coronary microvascular function, particularly after excluding severe epicardial coronary stenosis. The present study aimed to assess the relationship of QMP and D-CFVR in detecting coronary microvascular disease (CMVD) by using adenosine triphosphate stress myocardial contrast echocardiography (ATP stress MCE).

Methods and results

Seventy-two patients (mean age: 54.22 ± 12.78 years) with chest pain and <50% coronary stenosis diagnosed by quantitative coronary angiography or dual-source CT underwent ATP stress MCE. The distribution of myocardial perfusion and CFVR value was estimated by experienced physicians. Of the 72 LAD with 0%-50% diameter stenosis, 15 (21%) exhibited abnormal CFVR and 31 (43%) displayed abnormal perfusion with ATP stress MCE. Eleven of the 15 LAD territories (73%) with abnormal CFVR values showed abnormal perfusion. However, CFVR was considered normal in 20 LAD territories (35%), despite the presence of perfusion defect in the territory.

Conclusion

Abnormal myocardial perfusion during ATP stress MCE was found in a sizable percentage of patients in whom CFVR of the supplying vessel was considered normal.

The Need for Separate Testing with Acetylcholine for the Assessment of Endothelial Dysfunction and Coronary Artery Spasm

Intracoronary acetylcholine (ACH) testing is clinically useful to diagnose the presence of the coronary vasomotor disorders coronary endothelial dysfunction and coronary epicardial/microvascular spasm. In Western countries, continuous intracoronary injection of ACH for 2-3 minutes without a pacemaker is the usual method, while rapid injection of ACH for 20-30 seconds with a pacemaker is the traditional procedure in Japan. Coronary microvascular spasm is often observed in Western populations, whereas coronary epicardial spasm is frequently seen in Japanese subjects. Methodological differences between Western and Japanese protocols may lead to the opposite prevalence of coronary vasomotor disorders. This article discusses the optimal method for diagnosing endothelial dysfunction and epicardial/microvascular spasm based on previous reports, and compares intracoronary ACH testing performed by Western cardiologists with that by Japanese physicians.

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.

Coronary Artery Aneurysm or Ectasia as a Form of Coronary Artery Remodeling: Etiology, Pathogenesis, Diagnostics, Complications, and Treatment

Coronary artery aneurysm or ectasia (CAAE) is a term that includes both coronary artery ectasia (CAE) and coronary artery aneurysm (CAA), despite distinct phenotypes and definitions. This anomaly can be found in 0.15-5.3% of coronary angiography. CAE is a diffuse dilatation of the coronary artery at least 1.5 times wider than the diameter of the normal coronary artery in a patient with a length of over 20 mm or greater than one-third of the vessel. CAE can be further subdivided into diffuse and focal dilations by the number and the length of the dilated vessels. Histologically, it presents with extensive destruction of musculoelastic elements, marked degradation of collagen and elastic fibers, and disruption of the elastic lamina. Conversely, CAA is a focal lesion manifesting as focal dilatation, which can be fusiform (if the longitudinal diameter is greater than the transverse) or saccular (if the longitudinal diameter is smaller than the transverse). Giant CAA is defined as a 4-fold enlargement of the vessel diameter and is observed in only 0.02% of patients after coronary. An aneurysmal lesion can be either single or multiple. It can be either a congenital or acquired phenomenon. The pathophysiological mechanisms responsible for the formation of CAAE are not well understood. Atherosclerosis is the most common etiology of CAAE in adults, while Kawasaki disease is the most common in children. Other etiological factors include systemic connective tissue diseases, infectious diseases, vasculitis, congenital anomalies, genetic factors, and idiopathic CAA. Invasive assessment of CAAE is based on coronary angiography. Coronary computed tomography (CT) is a noninvasive method that enables accurate evaluation of aneurysm size and location. The most common complications are coronary spasm, local thrombosis, distal embolization, coronary artery rupture, and compression of adjacent structures by giant coronary aneurysms. The approach to each patient with CAAE should depend on the severity of symptoms, anatomical structure, size, and location of the aneurysm. Treatment methods should be carefully considered to avoid possible complications of CAAE. Simultaneously, we should not unnecessarily expose the patient to the risk of intervention or surgical treatment. Patients can be offered conservative or invasive treatment. However, there are still numerous controversies and ambiguities regarding the etiology, prognosis, and treatment of patients with coronary artery aneurysms. This study summarizes the current knowledge about this disease's etiology, pathogenesis, and management.

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.

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.

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.

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.

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.

Prevalence of Coronary Microvascular Dysfunction and Epicardial Spasm in Patients With Angina and Myocardial Bridge

Background

Myocardial bridges (MB) are prevalent but not universally associated with angina. The mechanisms linking MB and angina are poorly defined. The objective of this study was to determine the prevalence of epicardial spasm, microvascular spasm, and/or endothelium-independent coronary microvascular dysfunction (CMD) in patients with MB which might explain symptoms.

Methods

Patients with known MB and chest pain at the University of Chicago Medical Center between 2020-2023 were included. All patients underwent dobutamine testing with measurement of resting full-cycle ratio to determine hemodynamic significance (resting full-cycle ratio ≤0.76). Endothelium-independent CMD was defined as coronary flow reserve <2.0 or index of microvascular resistance ≥25 on adenosine testing. Microvascular spasm was defined as chest pain and electrocardiogram changes with nonischemic fractional flow reserve with acetylcholine. Epicardial spasm was defined as dynamic stenosis of >90% of the epicardial vessel or ischemic fractional flow reserve (≤0.8) with acetylcholine.

Results

A total of 30 patients (mean age, 47 ± 10 years; 60% female) with MB were studied. Endothelium-independent CMD, microvascular spasm, and epicardial spasm occurred commonly in 60%, 29%, and 37% of patients respectively, with 77% having at least one abnormality. The MB was hemodynamically significant in 47% of patients, and the prevalence of these coexisting conditions was not affected by hemodynamic significance.

Conclusions

Epicardial spasm, microvascular spasm, and endothelium-independent CMD are prevalent in patients presenting with known MB and chest pain irrespective of the hemodynamic significance of the bridge. Invasive coronary function testing may play an important role in uncovering alternative explanations for angina in patients with known MB.

Increased circulating levels of malondialdehyde-modified low-density lipoprotein in patients with coronary microvascular dysfunction

BACKGROUND

Coronary microvascular dysfunction (CMD) is associated with angina symptoms and adverse clinical outcomes in patients without obstructive coronary artery disease (CAD). Malondialdehyde-modified low-density lipoprotein (MDA-LDL) is reportedly a marker of the initiation and acceleration of epicardial coronary atherosclerosis. However, its impact on CMD remains unclear.

OBJECTIVE

We aimed to investigate the relationship between CMD and MDA-LDL levels.

METHODS

This study included 95 patients who did not receive lipid-lowering medications and had no obstructive CAD. Obstructive CAD was defined as >50% diameter reduction on coronary angiography or fractional flow reserve of ≤0.80. We retrospectively analyzed coronary flow reserve (CFR), index of microcirculatory resistance (IMR), and MDA-LDL levels. CMD was defined as either CFR <2.0 or IMR ≥25.

RESULTS

CMD was observed in 29 (31%) patients. MDA-LDL levels were significantly higher in patients with CMD than in those without CMD (124.8 ± 37.6 vs. 95.3 ± 29.5 U/L; p < 0.01). Univariable logistic regression analysis indicated a significant relationship between CMD and MDA-LDL levels (odds ratio (OR): 1.03; p < 0.01). In the multivariable model, MDA-LDL levels were significantly associated with CMD (OR: 1.02; p < 0.01). Regression analysis showed a significant correlation between MDA-LDL levels and CFR (r = -0.42, p < 0.01) and IMR (r = 0.35, p < 0.01). In the multiple regression analysis, MDA-LDL levels were independently associated with CFR (β = -0.30, p < 0.01) and IMR (β = 0.26, p = 0.02).

CONCLUSION

MDA-LDL levels were associated with CMD in patients without obstructive CAD.

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.

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).

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.

Spectrum of Non-Obstructive Coronary Artery Disease and Its Relationship with Atrial Fibrillation

This article aims to analyze the relationship between non-obstructive coronary artery disease (NOCAD) and atrial fibrillation (AF), exploring the underlying pathophysiological mechanisms and implications for clinical management. NOCAD and AF are prevalent cardiovascular conditions that often coexist, yet their interrelation is not well understood. NOCAD can lead to ischemic necrosis of cardiomyocytes and their replacement with fibrous tissue, sustaining focal ectopic activity in atrial myocardium. Atrial fibrillation, on the other hand, the most common sustained cardiac arrhythmia, is able to accelerate atherosclerosis and increase oxygen consumption in the myocardium, creating a mismatch between supply and demand, and thus promoting the development or worsening of coronary ischemia. Therefore, NOCAD and AF seem to be a complex interplay with one begets another.

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.

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.

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.

Clinical Updates in Coronary Artery Disease: A Comprehensive Review

Despite significant goals achieved in diagnosis and treatment in recent decades, coronary artery disease (CAD) remains a high mortality entity and continues to pose substantial challenges to healthcare systems globally. After the latest guidelines, novel data have emerged and have not been yet considered for routine practice. The scope of this review is to go beyond the guidelines, providing insights into the most recent clinical updates in CAD, focusing on non-invasive diagnostic techniques, risk stratification, medical management and interventional therapies in the acute and stable scenarios. Highlighting and synthesizing the latest developments in these areas, this review aims to contribute to the understanding and management of CAD helping healthcare providers worldwide.

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.