Coronary slow flow and angiography-derived index of microcirculatory resistance as prognostic predictors in patients with angina and normal coronary arteries: a retrospective cohort study.

BACKGROUND: This study aims to investigate prognostic implications of coronary slow flow (CSF) and angiography-derived index of microcirculatory resistance (caIMR) in patients with angina and normal coronary arteries. METHODS: A total of 582 patients were enrolled with angiographically normal coronary arteries. caIMR was calculated using a commercial software. Patients were followed up for a median of 45 months. The primary endpoint was defined as major adverse cardiovascular events (MACEs) comprising death, myocardial infarction and readmission for angina or heart failure. RESULTS: CSF was diagnosed when TIMI grade 2 flow presented in at least one coronary artery. Multivariate analysis indicated TIMI-flow-based determination of CSF was not significantly associated with MACEs [hazard ratio (HR): 2.14; 95% confidence interval (CI): 0.87-5.31; p = 0.099), while caIMR >42 (HR: 2.53; 95% CI: 1.02-6.32; p = 0.047) were independent predictors of MACEs. Incorporation of caIMR improved the area under the curve from 0.587 to 0.642. CONCLUSIONS: caIMR was an independent prognostic factor of long-term cardiovascular events in patients with CSF. Evaluation of caIMR improved the risk stratification of patients with angiographically-normal coronary arteries.

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.

[Angina and no obstruction on coronary angiography : New approaches to the diagnosis and treatment of vasomotor disorders]. / Angina pectoris ohne Stenosen in der Koronarangiographie : Neue Wege zur Diagnose und Therapie von Vasomotionsstörungen.

BACKGROUND: Clinical management of patients with angina and no obstructive coronary artery disease (ANOCA) is still challenging. This scenario affects up to 50% of patients undergoing diagnostic coronary angiography due to suspected coronary artery disease. Many patients report a long and debilitating history before adequate diagnostics and management are initiated. OBJECTIVES: This article describes the current recommendations for diagnostic assessments and treatment in patients with ANOCA. Focus is placed on invasive diagnostics in the catheter laboratory, pharmacological/interventional treatment as well as the patient journey. RESULTS: In patients with ANOCA, the current European Society of Cardiology (ESC) guidelines suggest that invasive assessments using acetylcholine and adenosine for the diagnosis of an underlying coronary vasomotor disorder should be considered. Acetylcholine is used to diagnose coronary spasm, whereas adenosine is used in conjunction with a wire-based assessment for the measurement of coronary flow reserve and microvascular resistance. The invasive assessments allow the determination of what are referred to as endotypes (coronary spasm, impaired coronary flow reserve, enhanced microvascular resistance or a combination thereof). Establishing a diagnosis is helpful to: (a) initiate targeted treatment to improve quality of life, (b) reassure the patient that a cardiac cause is found and (c) to assess individual prognosis. CONCLUSIONS: Currently, patients with ANOCA are often not adequately managed. Referral to specialised centres is recommended to prevent long and debilitating patient histories until expertise in diagnosis and treatment becomes more widespread.

Snare technique failure in extracting an embolized coronary sinus reducer to the pulmonary artery.

We report the case of a 79-year-old male patient who benefited from the implantation of a coronary sinus reducer (CSR) (Reducer; Neovasc, Inc.) in the management of typical angina with mild exertion with optimal medical treatment.

Long-term prognostic factors for cardiovascular events in patients with chest pain without diabetes mellitus nor significant coronary stenosis.

Chest pain is the most common symptom of coronary artery disease (CAD) and diabetes mellitus (DM) is a well-known single strongest risk factor for cardiovascular diseases. Thus, the impact of CAD nor DM on long-term clinical effects is reported widely, but the prognostic factors of non-DM patients presenting with chest pain without significant CAD are limited. A total of 1,046 patients with chest pain without DM and significant CAD who underwent coronary angiography (CAG) and acetylcholine (ACH) provocation tests were finally enrolled. Propensity score matching and multivariate Cox-proportional hazard ratio analysis were performed to adjust for baseline potential confounders. Major adverse cardiac and cerebrovascular events (MACCE) were defined as the composite of total death, myocardial infarction (MI), revascularization, stroke, and recurrent angina. This study aimed to evaluate the long-term prognostic factors for MACCE in patients with chest pain without DM and CAD up to 5 years. Coronary artery spasm (CAS) was the most common cause of chest pain. However, long-term MACCE of CAS was not worse than those of patients with chest pain without CAS when patients with CAS had subsequent optimal antianginal medication therapy. However, a recurrent chest pain remains a problem even with continuous antianginal medication therapy. Up to 5 years, the incidence of MACCE was in 7.3%, including recurrent angina 6.9%. Dyslipidemia (HR: 2.010, 95% CI 1.166-3.466, P = 0.012), mild-moderate (30-70%) coronary stenosis (HR: 2.369, 95% CI 1.118-5.018, P = 0.024), the use of aspirin (HR: 2.885, 95% CI 1.588-5.238, P < 0.001), and the use of nitrates (HR: 1.938, 95% CI 1.094-3.433, P = 0.023) were independent risk factors for MACCE. Among the patients with chest pain without DM and significant CAD, the incidence of MACE were rare, but recurrent angina was still a challenging problem who had treated with antianginal medications.

Hyperventilation testing in the diagnosis of vasospastic angina: A clinical review and meta-analysis.

BACKGROUND: Given the limited access to invasive vasospastic reactivity testing in Western Countries, there is a need to further develop alternative non-invasive diagnostic methods for vasospastic angina (VSA). Hyperventilation testing (HVT) is defined as a class IIa recommendation to diagnose VSA by the Japanese Society of Cardiology. METHODS: In this systematic review and meta-analysis reported according to the PRISMA statement, we review the mechanisms, methods, modalities and diagnostic accuracy of non-invasive HVT for the diagnostic of VSA. RESULTS: A total of 106 articles published between 1980 and 2022 about VSA and HVT were included in the systematic review, among which 16 were included in the meta-analysis for diagnostic accuracy. Twelve electrocardiogram-HVT studies including 804 patients showed a pooled sensitivity of 54% (95% confidence intervals [CI]; 30%-76%) and a pooled specificity of 99% (95% CI; 88%-100%). Four transthoracic echocardiography-HVT studies including 197 patients revealed a pooled sensitivity of 90% (95% CI; 82%-94%) and a pooled specificity of 98% (95% CI; 86%-100%). Six myocardial perfusion imaging-HVT studies including 112 patients yielded a pooled sensitivity of 95% (95% CI; 63%-100%) and a pooled specificity of 78% (95% CI; 19%-98%). Non-invasive HVT resulted in a low rate of adverse events, ventricular arrhythmias being the most frequently reported, and were resolved with the administration of nitroglycerin. CONCLUSIONS: Non-invasive HVT offers a safe alternative with high diagnostic accuracy to diagnose VSA in patients with otherwise undiagnosed causes of chest pain.

Comparison of clinical outcomes in patients with mixed angina and pure vasospastic angina.

OBJECTIVE: This study investigated differences in clinical outcomes between mixed angina (MA) and pure vasospastic angina (PVA). METHODS: A total of 524 vasospastic angina patients who did or did not have >50% coronary artery stenosis from January 2005 to January 2021 were divided into two groups (Group 1: PVA, N  = 399; Group 2: MA, N  = 125) and then three groups [Group 1: PVA, N  = 399; Group 2: MA without percutaneous coronary intervention (PCI), N  = 67; Group 3: MA with PCI, N  = 58] for assessment. We recorded the incidence of major adverse cardiac and cerebrovascular events (MACCE: the composite of death, myocardial infarction, nonfatal stroke or rehospitalization) during 3-year clinical follow-up. RESULTS: Compared to the PVA group, there were significant differences in MACCE (20.8% vs. 11.8%, P  = 0.011) and rehospitalization (20.0% vs. 9.8%, P  = 0.002) in the MA group. Kaplan-Meier analysis showed that patients in the MA with PCI group had the highest cumulative incidence rate of MACCE during the 3-year follow-up (log-rank P  < 0.001). CONCLUSION: Compared with the PVA patients, MA patients had significantly worse clinical outcomes during long-term follow-up.

Antianginal effects of empagliflozin in patients with type 2 diabetes and refractory angina; a randomized, double-blind placebo-controlled trial (EMPT-ANGINA Trial).

INTRODUCTION: Sodium-glucose cotransporter 2 (SGLT2) inhibitors are emerging antidiabetic agents with various potential cardiovascular benefits. The EMPT-ANGINA trial examined the effect of empagliflozin on the angina burden in those with concurrent type 2 diabetes mellitus (T2DM) and refractory angina (RA). METHOD: In this 8-week, double-blind, randomized, placebo-controlled trial, 75 patients with T2DM and RA were randomly assigned to one of two groups: empagliflozin (n = 37) and placebo (n = 38). The primary outcome was an improvement in angina, which was assessed by the Seattle Angina Questionnaire (SAQ). The secondary outcomes of this study included alterations in the SAQ domains and exercise test components. RESULTS: The mean age of individuals in the empagliflozin and placebo groups was 67.46 ± 9.4 and 65.47 ± 7.0 years, respectively (p = .304). Patients who received empagliflozin showed a significant improvement in both the primary endpoint, which was the SAQ Summary Score (192.73 ± 20.70 vs. 224 ± 25.36, p < .001) and the secondary endpoints. Exercise test components, including treadmill exercise duration, time till angina, 1 mm ST-segment depression onset, and heart rate (HR) recovery, were all significantly improved in the empagliflozin group. This positive impact was reached with no clinically significant changes in resting and exertion HR or blood pressure. There were no significant side effects in the empagliflozin group (p = .125). CONCLUSION: Empagliflozin can be safely added as a metabolic modulator agent to existing antianginal medications in individuals with concurrent T2DM and RA to reduce angina symptoms and enhance exercise capacity with minimal side effects.

A proposed tree-based explainable artificial intelligence approach for the prediction of angina pectoris.

Cardiovascular diseases (CVDs) are a serious public health issue that affects and is responsible for numerous fatalities and impairments. Ischemic heart disease (IHD) is one of the most prevalent and deadliest types of CVDs and is responsible for 45% of all CVD-related fatalities. IHD occurs when the blood supply to the heart is reduced due to narrowed or blocked arteries, which causes angina pectoris (AP) chest pain. AP is a common symptom of IHD and can indicate a higher risk of heart attack or sudden cardiac death. Therefore, it is important to diagnose and treat AP promptly and effectively. To forecast AP in women, we constructed a novel artificial intelligence (AI) method employing the tree-based algorithm known as an Explainable Boosting Machine (EBM). EBM is a machine learning (ML) technique that combines the interpretability of linear models with the flexibility and accuracy of gradient boosting. We applied EBM to a dataset of 200 female patients, 100 with AP and 100 without AP, and extracted the most relevant features for AP prediction. We then evaluated the performance of EBM against other AI methods, such as Logistic Regression (LR), Categorical Boosting (CatBoost), eXtreme Gradient Boosting (XGBoost), Adaptive Boosting (AdaBoost), and Light Gradient Boosting Machine (LightGBM). We found that EBM was the most accurate and well-balanced technique for forecasting AP, with accuracy (0.925) and Youden's index (0.960). We also looked at the global and local explanations provided by EBM to better understand how each feature affected the prediction and how each patient was classified. Our research showed that EBM is a useful AI method for predicting AP in women and identifying the risk factors related to it. This can help clinicians to provide personalized and evidence-based care for female patients with AP.

Gelanxinning capsule improves coronary microvascular dysfunction by inhibiting inflammation and restoring endothelial function.

OBJECTIVE: Gelanxinning capsule (GXSC) is a Chinese medicine to cure coronary artery disease (CAD) and a compound of Pueraria lobata, hawthorn extract, and gypenosides. However, whether GXSC could improve coronary microvascular dysfunction (CMD) is unknown. We aimed to demonstrate the therapeutic effect of GXSC on CMD and its underlying mechanisms in CAD patients. PATIENTS AND METHODS: This was a single-center, randomized control trial. A total of 78 patients diagnosed by selective coronary angiography (CAG) participated in this study. Patients' demographics, medical history, medications, and results of laboratory testing were collected. The index of microcirculatory resistance (IMR) and coronary flow reserve (CFR) were obtained by CAG and single-photon emission computed tomography (SPECT) separately. Fasting blood samples were obtained on the morning following the admission day. Concentrations of several molecules of inflammation, endothelial function, and coronary microvascular function were measured by ELISA. Patients were followed-up two months after discharge and fasting blood samples were also acquired. RESULTS: All patients were randomly divided into 2 groups: GXSC, 38 (48.7%), and control, 40 (51.3%). The intergroup comparison revealed no significant differences with respect to all baseline variables. As for inflammation biomarkers, proinflammatory NOD-like receptor thermal protein domain associated protein 3 (NLRP3) and interleukin (IL)-1 were significantly decreased in GXSC compared with the control group (0.71±0.08 vs. 1.04±0.07, p<0.01 and 7.16±0.59 vs. 10.93±1.04, p<0.01). Anti-inflammatory adropin was increased in the GXSC group (7.75±0.59 vs. 5.71±0.68, p=0.03). As for indexes of endothelial function, the concentrations of syndecan (SDC) 1, SDC4 and heparan sulphates (HS) were significantly downregulated in 2 months GXSC treatment (3.31±0.28 vs. 4.85±0.43, p<0.01, 3.79±0.56 vs. 5.69±0.68, p=0.03 and 21.31±2.79 vs. 35.18±4.11 p<0.01). In addition, the level of SIRTUIN 1 (SIRT1), which is a vascular protective protein, was upregulated in GXSC group (5.63±0.30 vs. 4.22±0.37, p<0.01). As for molecules of coronary microvascular function, endocan, soluble urokinase plasminogen activator receptor (suPAR), and growth differentiation factor (GDF)-15 were significantly decreased consistently in GXSC compared with the control group (0.09±0.01 vs. 0.19±0.03, p<0.01, 4.44±0.40 vs. 5.73±0.40, p=0.03 and 2.08±0.17 vs. 2.69±0.18, p=0.02). CONCLUSIONS: In conclusion, GXSC could improve CMD by inhibiting inflammation and restoring endothelial function. GXSC might be an effective drug in CAD patients without obstructive epicardial coronary arteries but suffering from angina.

Microvascular cardiac amyloidosis-Cardiac involvement of amyloidosis presenting as typical chest pain.

Coronary microvascular angina from cardiac amyloidosis.

Combination of Nicorandil and Beta-Adrenergic Receptor Blockers in Patients with Coronary Artery Disease: A Real-World Observational Study.

BACKGROUND: The effect of combined nicorandil and beta-adrenergic receptor blockers (BBs) compared with that of BBs alone on long-term clinical outcomes in patients with coronary artery disease (CAD) remains undetermined. METHODS: A multicenter retrospective cohort study was performed. Adult patients who had been hospitalized for CAD and treated for angina with a combination of nicorandil and BBs or BBs alone were included. The effect of different treatments on the cumulative incidence of major adverse cardiovascular event (MACE) and their components within a follow-up duration of 2.5 years were analyzed using Kaplan-Meier survival curves. An inverse probability of treatment weighting (IPTW) method was used to adjust for the possible effect of confounding factors. RESULTS: A total of 137,714 patients were screened, of whom 16,912 individuals (mean age: 61.5 years, men: 67.1%) were successfully enrolled. Among the enrolled participants, 4669 received the combined treatment of nicorandil and BBs, while 12,243 received BBs alone. After IPTW, the results demonstrated that the combined treatment was associated with a significantly reduced incidence of MACE (hazard ratio [HR] 0.79, 95% conidence interval [CI] 0.72-0.87) and stroke (HR 0.48, 95% CI 0.42-0.54) but not of MI (HR 1.03, 95% CI 0.92-1.15) or all-cause mortality (HR 0.93, 95% CI 0.64-1.37). Sensitivity analyses revealed similar results. CONCLUSIONS: A combined antiangina treatment of nicorandil and BBs may be more effective than treatment of BBs alone in reducing the long-term incidence of MACE in patients with CAD.

Diseases of the Coronary Microcirculation: Diagnosis and Treatment.

BACKGROUND: Coronary microvascular dysfunction (CMD) comprises a variety of pathogenic mechanisms that impair the microcirculation of the heart. Clinical studies have shown that 30-50% of patients suffering from myocardial ischemia without significant coronary artery stenosis have CMD. The disease is associated with ele - vated mortality and poor quality of life. Whenever a patient presents with symptoms of angina pectoris and no underlying disease is detected by the usual methods, CMD should be considered a possible cause. METHODS: This review is based on publications retrieved by a selective search in PubMed and on current international guidelines and recommendations of specialty societies. RESULTS: The diagnosis of CMD is based on objective evidence of a microvascular origin of symptoms. The guidelines contain a class IIa recommendation for invasive coronary flow reserve and microvascular resistance measurements. Noninvasive tests such as positron emission tomography and cardiac magnetic resonance imaging are less accurate and are given a class IIb recommendation. No highquality therapeutic trials are available to date, and the treatment of CMD is thus based on that of chronic coronary syndrome. Lifestyle modification is performed to reduce risk factors. Patients with an abnormal coronary flow reserve or elevated microvascular resistance can be treated with an ACE inhibitor or angiotensin receptor blocker. Beta-blockers and calcium channel antagonists can relieve angina pectoris. Statins lower the LDL level and have positive pleiotropic effects. First-line treatment can be supplemented with further medications. CONCLUSION: Approximately 25% of patients with CMD have symptoms that do not respond to intensive treatment with the currently available modalities. New treatments, including interventional therapies, are being studied. Their long-term benefit remains to be assessed and compared to that of the existing methods.

Continuous Versus Bolus Thermodilution-Derived Coronary Flow Reserve and Microvascular Resistance Reserve and Their Association With Angina and Quality of Life in Patients With Angina and Nonobstructive Coronaries: A Head-to-Head Comparison.

Background Coronary flow reserve (CFR) and microvascular resistance reserve (MRR) are physiological parameters to assess coronary microvascular dysfunction. CFR and MRR can be assessed using bolus or continuous thermodilution, and the correlation between these methods has not been clarified. Furthermore, their association with angina and quality of life is unknown. Methods and Results In total, 246 consecutive patients with angina and nonobstructive coronary arteries from the multicenter Netherlands Registry of Invasive Coronary Vasomotor Function Testing (NL-CFT) were investigated. The 36-item Short Form Health Survey Quality of Life and Seattle Angina questionnaires were completed by 153 patients before the invasive measurements. CFR and MRR were measured consecutively with bolus and continuous thermodilution. Mean continuous thermodilution-derived coronary flow reserve (CFRabs) was significantly lower than mean bolus thermodilution-derived coronary flow reserve (CFRbolus) (2.6±1.0 versus 3.5±1.8; P<0.001), with a modest correlation (ρ=0.305; P<0.001). Mean continuous thermodilution-derived microvascular resistance reserve (MRRabs) was also significantly lower than mean bolus thermodilution-derived MRR (MRRbolus) (3.1±1.1 versus 4.2±2.5; P<0.001), with a weak correlation (ρ=0.280; P<0.001). CFRbolus and MRRbolus showed no correlation with any of the angina and quality of life domains, whereas CFRabs and MRRabs showed a significant correlation with physical limitation (P=0.005, P=0.009, respectively) and health (P=0.026, P=0.012). In a subanalysis in patients in whom spasm was excluded, the correlation further improved (MRRabs versus physical limitation: ρ=0.363; P=0.041, MRRabs versus physical health: ρ=0.482; P=0.004). No association with angina frequency and stability was found. Conclusions Absolute flow measurements using continuous thermodilution to calculate CFRabs and MRRabs weakly correlate with, and are lower than, the surrogates CFRbolus and MRRbolus. Absolute flow parameters showed a relationship with physical complaints. No relationship with angina frequency and stability was found.

Vasospastic angina: Past, present, and future.

Vasospastic angina (VSA) is characterized by episodes of rest angina that are responsive to short-acting nitrates and are attributable to coronary artery vasospasm. The condition is underdiagnosed as the provocation test is rarely performed. VSA, the most important component of non-obstructive coronary artery disease, can present with angina, be asymptomatic, or can even present with fatal arrhythmias and cardiac arrest. Although most patients with VSA respond well to vasodilating medications, prognosis does not improve as expected in most patients, suggesting the existence elusive prognostic factors and pathogenesis that warrant further exploration. Moreover, patients with either severe or refractory VSA barely respond to conventional treatment and may develop life-threatening arrhythmias or suffer sudden cardiac death during ischemic attacks, which are associated with immune-inflammatory responses and have been shown to achieve remission following glucocorticoid and immunoglobulin treatments. Our recent work revealed that inflammation plays a key role in the initiation and development of coronary spasms, and that inflammatory cytokines have predictive value for diagnosis. In contrast to the existing literature, this review both summarizes the theoretical and clinical aspects of VSA, and also discusses the relationship between inflammation, especially myocarditis and VSA, in order to provide novel insights into the etiology, diagnosis, and treatment of VSA.