Coronary plaque component in patients with vasospastic angina: a virtual histology intravascular ultrasound study

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

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

What is the meaning of provoked spasm phenotypes by vasoreactivity testing?

Coronary artery epicardial spasm is involved in the pathogenesis of many cardiac disorders. Vasoreactivity testing, such as intracoronary injection of acetylcholine (ACH) or ergonovine (ER), is the gold standard method for the diagnosis of vasospastic angina. Provoked epicardial spasm phenotypes are classified as focal spasm and diffuse spasm. Multiple factors, including sex, ethnicity, and use of coronary vasoactive stimulators, are related to the provoked phenotypes of epicardial spasm. Diffuse-provoked spasm is often observed in females, where focal-provoked spasm is markedly more common in males. ACH provokes more diffuse and distal spasms, whereas ER induces more focal and proximal spasms. Yellow plaque and coronary thrombi are often observed in lesions with focal spasms, and intimal thickness with a sonolucent zone is significantly more common in lesions with focal spasm. Furthermore, clinical outcomes in patients with focal spasm are unsatisfactory compared with those in patients with diffuse spasm. However, the reproducibility and eternality of provoked spasm phenotypes by vasoreactivity testing is uncertain. Coronary atherosclerosis or endothelial damage may affect coronary vasomotor tone. Although coronary artery spasm may persist in the same coronary artery, provoked coronary spasm phenotypes may exhibit a momentary coronary reaction by intracoronary ACH or ER testing.

Coronary artery spasm treated with intracoronary bioresorbable scaffold implantation under the guidance of treadmill test and optical coherence tomography: A case report

Coronary artery spasm (CAS) can cause unstable angina, and the treatment of this disease is controversial. We report an elderly male patient who was admitted to hospital due to chest tightness. CAG showed that 70% stenosis in the middle of the right coronary artery (RCA). A bioresorbable scaffold (BRS) was implanted in the lesion under the guidance of optical coherence tomography (OCT). One year later, the patient's symptoms were relieved. The repeated CAG showed that the stent was good. BRS implantation under the guidance of treadmill test and OCT is one of treatment options for CAS patients.

Coronary Vasospastic Angina: A Review of the Pathogenesis, Diagnosis, and Management

Vasospastic angina (VSA) is an under-appreciated cause of chest pain. It is characterised by transient vasoconstriction of the coronary arteries and plays a significant role in the pathogenesis of stable angina and acute coronary syndromes. Complex mechanistic pathways characterised by endothelial dysfunction and smooth muscle hypercontractility lead to a broad spectrum of clinical manifestations ranging from recurrent angina to fatal arrhythmias. Invasive provocation testing using intracoronary acetylcholine or ergonovine is considered the current gold standard for diagnosis, but there is a wide variation in protocols amongst different institutions. Conventional pharmacological therapy relies on calcium channel blockers and nitrates; however, refractory VSA has limited options. This review evaluates the pathophysiology, diagnostic challenges, and management strategies for VSA. We believe global efforts to standardise diagnostic and therapeutic guidelines will improve the outcomes for affected patients.

Layered Plaque in Organic Lesions in Patients With Coronary Artery Spasm

Background

Coronary artery spasm plays a vital role in the pathogenesis of coronary plaques. We sought to investigate the plaque characteristics of co‐existing organic lesions in patients with coronary artery spasm in comparison to those without coronary artery spasm by intracoronary optical coherence tomography (OCT).

Methods and Results

We included 39 patients who presented with a symptom suspected of coronary spastic angina and had an organic lesion, defined as ≥plaque burden of 50% assessed by OCT. Coronary artery spasm was diagnosed by positive acetylcholine provocation test, or by spontaneous spasm detected during coronary angiography. A total of 51 vessels with an organic lesion were identified. Of these, coronary artery spasm was observed in 30 vessels (spasm), while not in 21 vessels (non‐spasm). Organic lesions in the spasm vessels, compared with those in the non‐spasm vessels, had a higher prevalence of layered plaque (93% versus 38%, P<0.001), macrophages (80% versus 43%, P=0.016), and intraplaque microchannels (73% versus 24%, P<0.001), and lower prevalence of macrocalcification (23% versus 62%, P=0.009) as assessed by OCT.

Conclusions

Layered plaque, macrophages, and intraplaque microchannels, were frequently observed in organic lesions in patients with coronary artery spasm. These findings suggest that coronary artery spasm induces local thrombus formation as well as active inflammatory response, therefore increasing the risk of rapid plaque progression and ischemic events in patients with coronary artery spasm.

A pathophysiological compass to personalize antianginal drug treatment

Myocardial ischaemia results from coronary macrovascular or microvascular dysfunction compromising the supply of oxygen and nutrients to the myocardium. The underlying pathophysiological processes are manifold and encompass atherosclerosis of epicardial coronary arteries, vasospasm of large or small vessels and microvascular dysfunction - the clinical relevance of which is increasingly being appreciated. Myocardial ischaemia can have a broad spectrum of clinical manifestations, together denoted as chronic coronary syndromes. The most common antianginal medications relieve symptoms by eliciting coronary vasodilatation and modulating the determinants of myocardial oxygen consumption, that is, heart rate, myocardial wall stress and ventricular contractility. In addition, cardiac substrate metabolism can be altered to alleviate ischaemia by modulating the efficiency of myocardial oxygen use. Although a universal agreement exists on the prognostic importance of lifestyle interventions and event prevention with aspirin and statin therapy, the optimal antianginal treatment for patients with chronic coronary syndromes is less well defined. The 2019 guidelines of the ESC recommend a personalized approach, in which antianginal medications are tailored towards an individual patient's comorbidities and haemodynamic profile. Although no antianginal medication improves survival, their efficacy for reducing symptoms profoundly depends on the underlying mechanism of the angina. In this Review, we provide clinicians with a rationale for when to use which compound or combination of drugs on the basis of the pathophysiology of the angina and the mode of action of antianginal medications.

Relation Between Cancer and Vasospastic Angina

INTRODUCTION

Patients with cancer have an increased risk of cardiovascular disease including ischemic heart disease and vice versa. Anticancer drugs and radiotherapy are known to contribute to endothelial injury and vasospasm. However, the relations between vasospastic angina (VSA) and cancer or its treatment are poorly investigated.

METHODS

A total of 786 patients underwent intracoronary acetylcholine (ACh) provocation tests to diagnose VSA. The positive ACh provocation test was defined as angiographic coronary artery spasm accompanied by chest pain and/or ischemic electrocardiographic changes. Patients were divided into active cancer, a history of cancer, and no cancer according to the status of malignancy. The impact of types of cancer, anticancer drugs, and radiotherapy on VSA was evaluated.

RESULTS

Of 786 patients, 38 (4.8%) and 84 (10.7%) had active cancer and a history of cancer, respectively, and 401 (51.0%) were diagnosed as VSA. There was no significant difference in rates of positive ACh test among patients with active cancer, a history of cancer, and no cancer (39.5% vs. 57.1% vs. 50.9%, p = 0.20). Types of cancer and cancer treatment also had no impact on positive ACh provocation test.

CONCLUSIONS

In this cross-sectional observational study, we did not find an association of active and a history of cancer with the diagnosis of VSA. Anticancer treatment including chemotherapy and radiotherapy was not significantly associated with positive ACh provocation test.

Myocardial infarction with non-obstructive coronary arteries (MINOCA): Intracoronary imaging-based diagnosis and management

Myocardial infarction with non-obstructive coronary arteries (MINOCA) is defined by clinical evidence of myocardial infarction (MI) with normal or near-normal coronary arteries on angiography. This condition is present in about 5% to 25% of patients presenting with acute coronary syndromes. MINOCA is a working diagnosis. Current guidelines and consensus recommend identification of underlying causes of MINOCA in order to optimize treatment, improve prognosis, and promote prevention of recurrent myocardial infarction. An accurate evaluation of patient history, symptoms and use of invasive and non-invasive imaging should lead to identification of epicardial or microvascular causes of MINOCA and differentiation from non-ischemic myocardial injury due to both cardiac (e.g. myocarditis) and non-cardiac disease (e.g. pulmonary embolism). In this review, we highlight the role of coronary imaging in differential diagnosis of patients presenting with MINOCA. Intravascular ultrasound and optical coherence tomography are well known technologies used in different settings from acute to chronic coronary syndromes. In MINOCA patients, coronary imaging could help to identify pathological alterations of the epicardial vessels that are not visible by coronary angiography such as plaque disruption, coronary dissection, coronary thromboembolism, coronary spasm, and coronary artery disease in patients presenting with takotsubo syndrome. In future, the widespread use of these technologies, in the right clinical context, could lead to optimization and personalization of treatment, and to better prognosis of patients presenting with MINOCA.

Coronary Plaque Characteristics and Cut-Off Stenosis for Developing Spasm in Patients with Vasospastic Angina

Coronary plaque distribution, frequency and cut-off value of percent stenosis for developing vasospasm are uncertain in patients with vasospastic angina (VA). We enrolled 2960 patients who received coronary angiography (CAG) and ergonovine provocation test prospectively in 11 university hospitals in Korea. A total of 1836 patients with VA and 867 without VA were included. Plaque and % stenosis were defined as ≥1% luminal narrowing and mean of each segmental stenosis. Overall frequency of plaque and % diameter stenosis was compared among VA-patients with index coronary spasm positive, those with index arterial spasm negative/other arterial spasm positive (INOP) and non-VA patients. Diameter stenosis associated with the spasm positivity was investigated. Overall plaque frequency and % stenosis were higher in VA patients than non-VA patients. Plaque frequency was 27.6% (243/881) in spasm positive at LAD, 16.4% (157/955) in LAD INOP and 12.6% (109/867) in non-VA with statistic difference (P < 0.001). Same trend for higher rate was observed in LCx and RCA. For % stenosis, 36.6 vs 32.4% (p = 0.010) in LAD, 36.1 vs. 28% (p < 0.001) in LCx and 35.3 vs.30.0% (p = 0.047) in RCA, respectively. Diameter stenosis of LAD with spasm positive vs. LAD INOP vs. non-VA were 38.3%, 34.0%, 32% (P = 0.002) with similar pattern in LCx and RCA. By multivariate logistic regression analysis, coronary stenosis of LAD ≥ 35% or LCx ≥35% or RCA ≥ 40% were independent predictor of developing spasm (OR 2.019, 95% CI 1.315–3.100, P = 0.001). In conclusions, spastic coronary artery had more plaque frequency, higher % stenosis than in non-spastic coronary in VA patients. The spasm related and unrelated coronary in VA patients had more plaque than in matched and unmatched coronary arteries in non-VA patients. Coronary stenosis ≥35% in LAD and LCx was an independent predictor of developing spasm.

Role of acetylcholine spasm provocation test as a pathophysiological assessment in nonobstructive coronary artery disease

Coronary angiography (CAG) sometimes shows nonobstructive coronary arteries in patients with suspected angina or acute coronary syndrome (ACS). The high prevalence of nonobstructive coronary artery disease (CAD) in those patients has recently been reported not only in Japan but also in Western countries, and is clinically attracting attention. Coronary spasm is considered to be one of the leading causes of both suspected stable angina and ACS with nonobstructive coronary arteries. Coronary spasm could also be associated with left ventricular dysfunction leading to heart failure, which could be improved following the administration of calcium channel blockers. Because we rarely capture spontaneous attacks of coronary spasm with electrocardiograms or Holter recordings, an invasive diagnostic modality, acetylcholine (ACh) provocation test, can be useful in detecting coronary spasm during CAG. Furthermore, we can use the ACh-provocation test to identify high-risk patients with coronary spasm complicated with organic coronary stenosis, and then treat with intensive care. Nonobstructive CAD includes not only epicardial coronary spasm but also microvascular spasm or dysfunction that can be associated with recurrent anginal attacks and poor quality of life. ACh-provocation test could also be helpful for the assessment of microvascular spasm or dysfunction. We hope that cardiologists will increasingly perform ACh-provocation test to assess the pathophysiology of nonobstructive CAD.

Spontaneous multivessel coronary artery spasm diagnosed with intravascular ultrasound imaging: A case report

BACKGROUND

Coronary artery spasm is a major cause of myocardial ischemia. Although coronary artery spasm has been known for a long time, its mechanism has not yet been identified. Many clinicians, especially young clinicians pay less attention to coronary artery spasm, which may lead to some patients not being appropriately diagnosed and treated in time. We report a patient with spontaneous multivessel coronary artery spasm for more than 30 years diagnosed with intravascular ultrasound (IVUS) imaging.

CASE SUMMARY

A 66-year-old Chinese male patient had chest squeezing at rest for more than 30 years. He had a history of cigarette smoking for more than 40 years and hypertension for 10 years. Before presenting at our institution, the patient had undergone coronary angiography 4 times and percutaneous transluminal coronary angioplasty procedures twice at other hospitals without a diagnosis of coronary artery spasm. However, his chest symptoms worsened. Spontaneous multivessel coronary artery spasm occurred during IVUS without provocation testing, and the IVUS image was recorded. Thus, the diagnosis of multifocal spontaneous coronary artery spasm was confirmed. The patient was placed on oral diltiazem, isosorbide mononitrate, and nicorandil to suppress coronary artery spasms. All medications were given at the maximum dosages tolerated by the patient. He was discharged after 5 d without complications. During the six-month follow-up period, the patient was symptom-free.

CONCLUSION

Coronary artery spasm is still prevalent in Eastern countries. It is essential for clinicians to be aware of coronary artery spasm, which may be hard to detect and can be lethal, in order to diagnose and treat patients appropriately.

Coronary Artery Spasm: New Insights

Coronary artery spasm (CAS) defined by a severe reversible diffuse or focal vasoconstriction is the most common diagnosis among INOCA (ischemia with no obstructive coronary artery disease) patients irrespective to racial, genetic, and geographic variations. However, the prevalence of CAS tends to decrease in correlation with the increasing use of medicines such as calcium channel blockers, angiotensin converting enzyme inhibitor, and statins, the controlling management of atherosclerotic risk factors, and the decreased habitude to perform a functional reactivity test in highly active cardiac catheterization centers. A wide spectrum of clinical manifestations from silent disease to sudden cardiac death was attributed to this complex entity with unclear pathophysiology. Multiple mechanisms such as the autonomic nervous system, endothelial dysfunction, chronic inflammation, oxidative stress, and smooth muscle hypercontractility are involved. Regardless of the limited benefits proffered by the newly emerged cardiac imaging modalities, the provocative test remains the cornerstone diagnostic tool for CAS. It allows to reproduce CAS and to evaluate reactivity to nitrates. Different invasive and noninvasive therapeutic approaches are approved for the management of CAS. Long-acting nondihydropyridine calcium channel blockers are recommended for first line therapy. Invasive strategies such as PCI (percutaneous coronary intervention) and CABG (coronary artery bypass graft) have shown benefits in CAS with significant atherosclerotic lesions. Combination therapies are proposed for refractory cases.

Diagnosis of myocardial infarction at autopsy: AECVP reappraisal in the light of the current clinical classification

Ischemic heart disease is one of the leading causes of morbidity and death worldwide. Consequently, myocardial infarctions are often encountered in clinical and forensic autopsies, and diagnosis can be challenging, especially in the absence of an acute coronary occlusion. Precise histopathological identification and timing of myocardial infarction in humans often remains uncertain while it can be of crucial importance, especially in a forensic setting when third person involvement or medical responsibilities are in question. A proper post-mortem diagnosis requires not only up-to-date knowledge of the ischemic coronary and myocardial pathology, but also a correct interpretation of such findings in relation to the clinical scenario of the deceased. For these reasons, it is important for pathologists to be familiar with the different clinically defined types of myocardial infarction and to discriminate myocardial infarction from other forms of myocardial injury. This article reviews present knowledge and post-mortem diagnostic methods, including post-mortem imaging, to reveal the different types of myocardial injury and the clinical-pathological correlations with currently defined types of myocardial infarction.

Intracoronary focal nitroglycerin injection through drilled balloon is very effective in the resolution of coronary spasm versus into proximal coronary artery: A prospective randomized comparison study

BACKGROUND

In this study, we aimed to compare the effectiveness and safety of NTG administration via catheter and local NTG infusion through a perforated balloon in order to prevent coronary spasm from developing during percutaneous intervention.

METHOD

The study began with 1:1 randomization into two groups of a total of 1688 patients scheduled for PCT. A total of 91 patients in the proximal group who developed lesions received 500 mcg NTG through a catheter, while 85 patients in the local group with lesions developed during the procedure received 500 mcg local NTG through a perforated balloon. After excluding patients who did not develop lesions during the procedure, and those without any change in the lesion with NTG application, the study was completed with 74 patients in the local group, and 70 patients in the proximal group.

RESULTS

Both groups were similar in terms of basic characteristics. Incidences of procedure-related hypotension (10% vs 52%, P < 0.001) and tachycardia (20% vs 57%, P < 0.001) were significantly lower in the local NTG group. Success in addressing spasm was significantly higher in the local NTG than in the proximal NTG group (91.66 ± 14.09% vs 75.99 ± 16.86%, P < 0.001).

DISCUSSION

Intracoronary injection with a perforated balloon, a simple technique introduced worldwide with our publication, can be used for administration of local NTG. Using this method, NTG can be better delivered with the perforated balloon to the vascular epithelium because of lower output, higher eruption rate, and perpendicularity to the endothelium. In this application, the balloon can better deliver drugs to the desired area via back-and-forth movements using a 0.014 guidewire.

CONCLUSION

The local administration of NTG to a spasming area through a perforated balloon is more effective and safer than the proximal administration of NTG.

Atherosclerotic Coronary Plaque Development Visualized by In Vivo Coronary Imaging

In the past decades, coronary imaging has evolved as a valuable adjunct to angiography, providing scientific insights into vascular biology and practical guidance by direct visualization of atherosclerosis and other pathologic conditions within the vessel walls. Especially with intravascular ultrasound (IVUS), the signal is able to penetrate below the luminal surface, so the entire cross-section of an artery, including the complete thickness of the plaque, can be imaged in real-time. On the other hand, optical coherence tomography (OCT) has been offering higher image resolution of both the plaque and the luminal surface. These technologies offer the opportunity to gather diagnostic information about the process of atherosclerosis and to directly observe the effects of various interventions on the plaque and arterial walls. IVUS has proven itself to be a practical and useful tool in the evaluation and optimal guidance of interventional vascular medicine. In this review, we detail the current modalities of coronary imaging and their usefulness in the diagnosis and management of patients with high-risk coronary plaques.

Assessing Vessel Tone during Coronary Artery Spasm by Dual-Acquisition Multidetector Computed Tomography Angiography

BACKGROUND

Diminished vascular tone is an established biomarker of heart damage. Little is known about the extent of coronary vessel tone (CVT) with spasm as assessed by dual-acquisition multidetector computed tomography angiography (MCTA) in patients with vasospastic angina (VSA).

OBJECTIVE

We evaluated the CVT modulated by intravenous nitrate injection (INI) using MCTA imaging in VSA patients.

METHODS

Twenty-one VSA patients (60 ± 9 years; 76% males) who underwent initial MCTA (without morning vasodilation), followed by an intracoronary ergonovine provocation test were included. Within 3 days after the initial MCTA patients received INI followed by 28-vessel segment spasm analyzed by MCTA 3D software, applying the following formula as the definition of CVT index (CVTI): (CSAIV nitrate - CSAinitial/CSAIV nitrate) ×100 %, where CSA is the cross-sectional area.

RESULTS

Compared to the initial MCTA measures, the INI provocation resulted in the significant increase of average diameter and CSA at the spasm site (2.60 mm [2.11-3.16] vs. 1.42 mm [1.13-2.13]; 5.37 mm2 [3.67-7.54] vs. 1.62 mm2 [1.02-3.02]; p < 0.001). The CVTI at the spastic segments was higher than at the proximal reference segments (41.0% [21.8-52.3] vs. 18.8% [5.9-26.6] for CVTI diameter; 65.1% [38.6-77.0] vs. 33.9% [5.2-48.1] for CVTI CSA, respectively). To predict VSA, the cut-off value for CVTI diameter was 38.6% (AUC 0.777; 95% CI 0.653-0.901) and 62.5% (AUC 0.779; 95% CI 0.657-0.902) for CVTI CSA in a receiver-operating characteristic curve analysis, with 57.1% sensitivity and 92.9% specificity.

CONCLUSIONS

This novel imaging technique for assessing CVT by dual-acquisition MCTA after applying INI provocation is suitable for the detection of coronary artery spasm in patients with VSA.

In Vivo optical coherence tomography visualization of intraplaque neovascularization at the site of coronary vasospasm: a case report

Background

Coronary plaques in patients with coronary vasospastic angina have been characterized by diffuse intima-media thickening with homogeneous fibrous tissue, without confluent necrotic tissue. However, coronary vasospasm can trigger coronary thrombosis, and may play an important role in the pathogenesis of acute coronary syndromes, though the precise morphological mechanisms underlying this process remain unclear.

Case presentation

A 43-year-old man with a history of multivessel coronary vasospastic angina had been treated with long-acting diltiazem and fluvastatin since 2004. Eleven years later, following 1 month of medication nonadherence, he experienced recurrence of rest angina and myocardial infarction, with elevated high-sensitivity troponin T. An emergency coronary angiogram demonstrated no de novo lesions, and the current episode was diagnosed as intractable sustained coronary spasm-induced anterior myocardial infarction. Optical coherence tomography imaging revealed the coronary plaque with homogeneous high-intensity signal, and a clearly visualized intraplaque neovascular microchannel (NVMC) network.

Conclusions

Neovascularization within a coronary atheroma is known to accelerate coronary atherosclerosis. The current case with coronary vasospastic angina highlights the role of NVMC formation in this process.

Electronic supplementary material

The online version of this article (doi:10.1186/s12872-016-0408-y) contains supplementary material, which is available to authorized users.

Clinical and morphological presentations of acute coronary syndrome without coronary plaque rupture - An intravascular ultrasound study

BACKGROUND

Although acute coronary syndrome (ACS) mainly arises from plaque ruptures (PR), precise mechanisms underlying ACS without PR are unknown. We sought to examine clinical, angiographic and intravascular ultrasound (IVUS) characteristics of ACS without PR.

METHODS AND RESULTS

Culprit lesions of 161 ACS patients were categorized by the presence or absence of PR (PR group: n=57, Non-PR group: n=104). Lower abdominal circumference (86±10cm vs 90±9cm, p=0.02), lower prevalence of myocardial infarction (53% vs 82%, p=0.0002), and higher prevalence of definite vasospasm (15% vs 2%, p=0.006) were found in Non-PR group. Morphologically, Non-PR group was associated with simpler Ambrose classification (36% vs 14%, p=0.004), less hypoechoic plaque (45% vs 65%, p=0.04) and lower incidence of IVUS-detected thrombus (21% vs 54%, p<0.0001), compared with PR group. On quantitative IVUS, although minimum lumen area (MLA) was similar between the groups, vessel (14.2±5.4mm(2) vs 17.5±5.1mm(2), p=0.0002) and plaque (11.6±5.0mm(2) vs 14.9±4.9mm(2), p<0.0001) areas were significantly smaller at MLA site in Non-PR group than in PR group. On multivariate analysis, average plaque area was only an independent IVUS-predictor of non-rupture ACS (odds ratio: 0.85, p=0.01).

CONCLUSION

Compared to ACS with PR, non-rupture ACS arise from more hyperechoic (allegedly "stable") plaque with smaller vessel and plaque area, leading to lower incidence of thrombotic occlusion. Coronary vasospasm might be a possible pathogenic mechanism underlying non-rupture ACS.

A Case of Spontaneous Multivessel Coronary Artery Spasm That Underwent Stent Implantation Accompanying ST Segment Elevation on Inferior Electrocardiographic Leads

Coronary artery spasm is usually defined as a focal constriction of a coronary artery segment, which is reversible, and causes myocardial ischaemia by restricting coronary blood flow. A coronary spasm may rarely compromise all three epicardial arteries simultaneously. We present a case of severe coronary spasm afflicting all coronary arteries accompanying an ST segment elevation in leads D2-D3 and aVF.

Chest CT examinations in patients presenting with acute chest pain: a pictorial review

Acute chest pain (ACP) is one of the most common presenting symptoms at the emergency department. The differential diagnosis is vast. To exclude life-threatening causes, radiologists encounter an increasing amount of thoracic computed tomography (CT) examinations including CT angiography of the heart and great vessels. The dual- and triple-rule CT examinations are currently implemented in clinical practice. We retrospectively identified chest CT examinations in the setting of acute chest pain in our hospitals and collected a variety of common and uncommon cases. In this pictorial essay, we present the most educative cases from patients who presented with acute chest pain in the emergency department of our hospitals and for whom a thoracic CT was ordered. When aortic emergencies, acute coronary syndrome, and pulmonary embolism are excluded, these cases may help the radiologist to suggest alternative diagnoses in the diagnostic challenge of acute chest pain.

Teaching Points

• The number of chest CT examinations for ACP is increasing.

• Chest CT examinations may help suggesting alternative diagnosis in ACP.

• Radiologists should be aware of the differential diagnosis of ACP.

OCT-Defined Morphological Characteristics of Coronary Artery Spasm Sites in Vasospastic Angina

OBJECTIVES

The aim of this study was to define the morphological features of coronary artery spasm sites using optical coherence tomography (OCT) in patients with vasospastic angina (VSA).

BACKGROUND

Plaque characteristics at coronary artery spasm sites have not been investigated systematically.

METHODS

Sixty-nine consecutive patients (80 spasm sites) presenting with VSA who underwent OCT imaging were included in this study. Fibrous cap disruption was identified by the discontinuation of fibrous cap with or without intraplaque cavity formation. OCT-defined erosion was established by the presence of thrombus with or without lumen irregularity overlying an intact fibrous cap on multiple adjacent OCT frames. Other morphological features such as the absence of thrombus with or without lumen irregularity and those not in the previously mentioned criteria were also documented.

RESULTS

Plaque was seen on OCT in 79 of the 80 spasm sites. Fibrous cap disruption was detected at 3 sites (4%). OCT-defined erosion was observed at 21 spasm sites (26%). Thrombus with lumen irregularity was observed in 20 sites, whereas 1 site had thrombus without lumen irregularity. Lumen irregularity without thrombus was observed at 49 spasm sites (61%). Spontaneous spasm was seen more frequently in patients with acute myocardial infarction and out-of-hospital cardiac arrest than in patients without these conditions (50.0% vs. 19.3%, p = 0.025).

CONCLUSIONS

Our results show that OCT-defined erosion at spasm sites occurred in more than one-fourth of patients in this study. Luminal irregularity was observed in nearly two-thirds of the patients without overlying thrombus. These findings suggest the potential role of antiplatelet therapy in VSA.

Single-wire pressure and flow velocity measurement for quantifying microvascular dysfunction in patients with coronary vasospastic angina

Endothelial and vascular smooth muscle dysfunction of epicardial coronary arteries play a pivotal role in the pathogenesis of vasospastic angina (VSA). However, coronary microvascular (MV) function in patients with VSA is not fully understood. In the present study, subjects without coronary obstruction were divided into two groups according to the acetylcholine provocation test: VSA group ( n = 29) and non-VSA group ( n = 21). Hyperemic MV resistance (hMR) was measured using a dual-sensor (Doppler velocity and pressure)-equipped guidewire, and guidewire-derived hemodynamic parameters were compared. There were no between-group differences in clinical demographics, including potential factors affecting MV function (e.g., diabetes). Although coronary flow velocity reserve was similar between the two groups [2.4 ± 1.0 (VSA group) vs. 2.4 ± 0.9 (non-VSA group); P = 0.8], coronary vessel resistance and hMR were significantly elevated in the VSA group compared with the non-VSA group (2.6 ± 3.1 vs. 1.2 ± 0.8, P = 0.04; 1.9 ± 0.6 vs. 1.6 ± 0.5, P = 0.03, respectively). Coronary vasospasm, older age, E/e', and estimated glomerular filtration rate were significantly associated with MV dysfunction [defined as ≥ median value of hMR (1.6)] in univariate analysis. Coronary vasospasm most strongly predicted higher hMR in multivariate logistic regression analysis (odds ratio, 4.61; 95% confidence interval, 0.98–21.60; P = 0.053). In conclusion, coronary MV resistance is impaired in patients with VSA compared with non-VSA patients, whereas coronary flow velocity reserve is maintained at normal levels in both groups. In vivo assessment of hMR might be a promising index of coronary MV dysfunction in patients with VSA.

Some observations on and controversies about coronary arterial spasm

The pathogenesis, clinical features, diagnosis, and treatment of spasm of epicardial coronary arteries are reviewed briefly, especially with regard to some issues that remain controversial. For diagnosis, emphasis is placed on the need for objective observations during an attack, even if that requires an attempt at pharmacologic provocation during coronary arteriography, or during echocardiography when prior arteriography has demonstrated the absence of severe coronary stenosis.

Favorable outcomes of patients with vasospastic angina associated with cardiac arrest

BACKGROUND

The long-term survival of vasospastic angina (VSA) patients is generally good, so long as they remain on calcium channel blockers (CCBs) and avoid smoking. However, the pathogenesis, appropriate treatments, and prognosis of VSA associated with cardiac arrest remain unclear. This study aimed to elucidate the clinical features and long-term outcomes of patients with VSA associated with cardiac arrest.

METHODS AND RESULTS

Eighteen consecutive patients with VSA associated with cardiac arrest [13 patients resuscitated after out-of-hospital cardiac arrest (OHCA) and 5 resuscitated after in-hospital-cardiac arrest] were retrospectively analyzed. Sixteen of the eighteen patients were smokers. None had other cardiac diseases possibly causing cardiac arrest. Although 1 patient resuscitated after OHCA later died of cerebral hypoxia, the remaining 17 were discharged without complications. One patient died of cancer 50 months after resuscitation. The other 16 patients are still alive and none have shown ventricular arrhythmias, syncope, or cardiac arrest during a mean follow-up of 67 months. All are treated with long-acting CCBs/nitrates and successfully quit smoking. Six patients received implantable cardioverter defibrillators (ICD). However, none demonstrated any ventricular arrhythmias and appropriate ICD actuation was achieved.

CONCLUSION

Appropriate medical treatment can achieve favorable long-term outcomes even for patients with VSA associated with cardiac arrest.

Coronary spasm and acute myocardial infarction due to a mutation (V734I) in the nucleotide binding domain 1 of ABCC9

BACKGROUND

Alterations in coronary vasomotor tone may participate in the pathogenesis of acute myocardial infarction (AMI). Vascular ATP-sensitive K(+) (KATP) channels, formed by Kir6.x/SUR2B, are key regulators of coronary tone and mutations in cardiac (Kir6.2/SUR2A) KATP channels result in heart disease. Here we explore the pathophysiological mechanism of a rare mutation (V734I) found in exon 17 of the ABCC9 gene, estimated to cause a 6.4-fold higher risk of AMI before the age of 60.

METHODS AND RESULTS

Eleven patients carrying the mutation were identified; they presented AMI of vasospastic origin associated with increased plasma levels of endothelin-1 and increased leukocyte ROCK activity. The effects of the mutation on the functional properties of the two splice variants of ABCC9 (SUR2A and SUR2B) were studied using patch-clamp electrophysiology. The mutation reduced the sensitivity to MgATP inhibition of Kir6.2/SUR2B channels but not of Kir6.2/SUR2A and Kir6.1/SUR2B channels. Furthermore, the stimulatory effects of MgNDP (MgADP, MgGDP and MgUDP) were unaltered in mutant Kir6.2/SUR2A and Kir6.1/SUR2B channels. In contrast, mutant channels composed of Kir6.2 and SUR2B were less sensitive to MgNDP activation, assessed in the presence of MgATP. The antianginal drug nicorandil activated Kir6.2/SUR2B-V734I channels, thus substituting for the loss of MgNDP stimulation, suggesting that this drug could be of therapeutic use in the treatment of AMI associated with V734I.

CONCLUSIONS

The 734I allele in ABCC9 may influence susceptibility to AMI by impairing the response of vascular, but not cardiac, KATP channels to intracellular nucleotides. This is the first human mutation in an ion channel gene to be implicated in AMI.