Mechanisms of Coronary Artery Spasm

Recent clinical trials have highlighted that percutaneous coronary intervention in patients with stable angina provides limited additional benefits on top of optimal medical therapy. This has led to much more attention being paid to coronary vasomotion abnormalities regardless of obstructive or non-obstructive arterial segments. Coronary vasomotion is regulated by multiple mechanisms that include the endothelium, vascular smooth muscle cells (VSMCs), myocardial metabolic demand, autonomic nervous system and inflammation. Over the years, several animal models have been developed to explore the central mechanism of coronary artery spasm. This review summarises the landmark studies on the mechanisms of coronary vasospasm demonstrating the central role of Rho-kinase as a molecular switch of VSMC hypercontraction and the important role of coronary adventitial inflammation for Rho-kinase upregulation in VSMCs.

Management of Coronary Artery Spasm

Calcium channel blockers (CCBs) are the first-line treatment for coronary artery spasm (CAS). When CAS-related angina symptoms are not well controlled by CCB therapy, long-acting nitrates or (where available) nicorandil can be added as second-line medications. In the case of CAS refractory to standard treatments, several other alternative drugs and interventions have been proposed, including the Rho-kinase inhibitor fasudil, anti-adrenergic drugs, neural therapies and percutaneous coronary interventions. In patients with syncope or cardiac arrest caused by CAS-related tachyarrhythmias, or even bradyarrhythmias, implantation of an ICD or pacemaker, respectively, should be considered according to the risk of recurrence and efficacy of vasodilator therapy.

Association of the extent of myocardial ischemia with outcomes in patients with suspected coronary artery disease in Japan

BACKGROUND

There is an ongoing controversy regarding the necessity of single-photon emission computed tomography (SPECT) for patients with ischemic heart diseases after the publication of the results of the ISCHEMIA trial. We aimed to evaluate the association of the extent of myocardial ischemia with outcomes in patients with suspected coronary artery disease in Japan.

METHODS

From the data of 2780 patients with stable angina who were enrolled prospectively between January 2006 and March 2008 in Japan and had undergone physician-referrednon-invasive imaging tests (Japanese Coronary-Angiography or Myocardial Imaging for Angina Pectoris Study), 1205 patients managed with SPECT were stratified by 10% myocardial ischemia. Major adverse cardiac events (MACEs), including death, myocardial infarction, hospitalization for heart failure, and late revascularization, were followed-up for 1year.

RESULTS

Patients with ≥10% myocardial ischemia (n=173) were less likely to be women than patients with <10% myocardial ischemia (n=1032) and had a significantly higher 1-year cumulative incidence of MACEs (6.9% vs. 1.8%, p<0.0001). After adjusting for confounders, the risk of ≥10% myocardial ischemia relative to <10% myocardial ischemia for MACEs remained significant [adjusted hazard ratio (95% confidence interval), 2.40 (1.09-5.26), p=0.029]. After adjusting including treatments, the risk of MACEs became insignificant between the ≥10% myocardial ischemia group and the <10% myocardial ischemia group [adjusted hazard ratio (95% confidence interval), 1.04 (0.45-2.45), p=0.92].

CONCLUSION

The presence of ≥10% myocardial ischemia at diagnosis was significantly associated with the 1-year risk for MACEs in Japanese patients with suspected coronary artery disease.

New use of old medicine: Nifedipine acts on the TRP family and inflammatory proteins in the treatment of chilblain

As a calcium antagonist, the mechanism of nifedipine for treating chilblain has not been reported. In the present study, we established the chilblain model by using -20 ℃ 95% ethanol to freeze the right back foot of SD rats, and investigated the effects of this drug. Hematoxylin-eosin (HE) examination indicated most of pannus in the skin tissue of chilblain rats had disappeared, and the local inflammatory cells were also greatly reduced when given nifedipine at 15.0 mg/kg/d. The enzyme-linked immunosorbent assay (ELISA) revealed that nifedipine inhibited release of inflammatory factors TNF-α, IL-6, IL-1β and VEGF in serum. The RT-PCR analysis showed that nifedipine down regulated mRNA levels of TRPC-6 and VEGF in skin tissue. Furthermore, immunohistochemical examination showed nifedipine inhibited expression of IL-1β, IL-6, and TNF-α inflammatory protein and further inhibited expression of TRP (transient receptor potential) family proteins TRPM-7, TRPC-1, TRPC-3 and TRPC-6 and reduced expression of VEGF in skin and relieved erythema and oedema. This study demonstrated that nifedipine as an old medicine can be new use for the treatment of chilblain by acting on TRPs family and inflammatory proteins.

Prognostic Impacts of Comorbid Significant Coronary Stenosis and Coronary Artery Spasm in Patients With Stable Coronary Artery Disease

BACKGROUND Stable coronary artery disease is caused by a variable combination of organic coronary stenosis and functional coronary abnormalities, such as coronary artery spasm. Thus, we examined the clinical importance of comorbid significant coronary stenosis and coronary spasm. METHODS AND RESULTS We enrolled 236 consecutive patients with suspected angina who underwent acetylcholine provocation testing for coronary spasm and fractional flow reserve (FFR) measurement. Among them, 175 patients were diagnosed as having vasospastic angina (VSA), whereas the remaining 61 had no VSA (non-VSA group). The patients with VSA were further divided into the following 3 groups based on angiography and FFR: no organic stenosis (≤50% luminal stenosis; VSA-alone group, n=110), insignificant stenosis of FFR>0.80 (high-FFR group, n=36), and significant stenosis of FFR≤0.80 (low-FFR group, n=29). The incidence of major adverse cardiovascular events, including cardiovascular death, nonfatal myocardial infarction, urgent percutaneous coronary intervention, and hospitalization attributed to unstable angina was evaluated. All patients with VSA received calcium channel blockers, and 28 patients (95%) in the low-FFR group underwent a planned percutaneous coronary intervention. During a median follow-up period of 656 days, although the incidence of major adverse cardiovascular events was low and comparable among non-VSA, VSA-alone, and high-FFR groups, the low-FFR group had an extremely poor prognosis (non-VSA group, 1.6%; VSA-alone group, 3.6%; high-FFR group, 5.6%; low-FFR group, 27.6%) (P<0.001). Importantly, all 8 patients with major adverse cardiovascular events in the low-FFR group were appropriately treated with percutaneous coronary intervention and calcium channel blockers. CONCLUSIONS These results indicate that patients with VSA with significant coronary stenosis represent a high-risk population despite current guideline-recommended therapies, suggesting the importance of routine coronary functional testing in this population.

Beta blockers versus calcium channel blockers for provocation of vasospastic angina after drug-eluting stent implantation: a multicentre prospective randomised trial

Background

Drug-eluting stent-induced vasospastic angina (DES-VSA) has emerged as a novel complication in the modern era of percutaneous coronary intervention (PCI). Although beta blockers (BBs) are generally recommended for coronary heart disease, they may promote incidence of DES-VSA. This study aimed to compare the effects of calcium channel blockers (CCBs) perceived to be protective against DES-VSA and BBs on subsequent coronary events after second-generation drug-eluting stent implantation.

Methods

In this multicentre prospective, randomised study, 52 patients with coronary artery disease who underwent PCI for a single-vessel lesion with everolimus-eluting stent placement were randomised into post-stenting BB (N=26) and CCB (N=26) groups and followed for 24 months to detect any major cardiovascular events (MACE). A positive result on acetylcholine provocation testing during diagnostic coronary angiography (CAG) at 9 months was the primary endpoint for equivalence. MACE included all-cause death, non-fatal myocardial infarction, unstable angina, cerebrovascular disease or coronary revascularisation for stable coronary artery disease after index PCI.

Results

At 9 months, 42 patients (80.8%) underwent diagnostic coronary angiography and acetylcholine provocation testing. Among them, seven patients in each group were diagnosed with definite vasospasm (intention-to-treat analysis 26.9% vs 26.9%, risk difference 0 (−0.241, 0.241)). Meanwhile, the secondary endpoint, 24-month MACE, was higher in the CCB group (19.2%) than in the BB group (3.8%) (p=0.01). In detail, coronary revascularisation for stable coronary artery disease was the predominant endpoint that contributed to the greater proportion of MACE in the CCB group (CCB (19.2%) vs BB (3.8%), p=0.03).

Conclusions

The incidence of acetylcholine-induced coronary artery spasms did not differ between patients receiving BBs or CCBs at 9 months after PCI. However, a higher incidence of 2-year MACE was observed in the CCB group, suggesting the importance of BB administration.

Trial registration number

This study was registered at the Japanese University Hospital Medical Information Network (UMIN) Clinical Trial Registry (The Prospective Randomized Trial for Optimizing Medical Therapy After Stenting: Calcium-Beta Trial; UMIN000008321, https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000009536).

Mechanisms and diagnostic evaluation of persistent or recurrent angina following percutaneous coronary revascularization

Persistence or recurrence of angina after a percutaneous coronary intervention (PCI) may affect about 20-40% of patients during short-medium-term follow-up. This appears to be true even when PCI is 'optimized' using physiology-guided approaches and drug-eluting stents. Importantly, persistent or recurrent angina post-PCI is associated with a significant economic burden. Healthcare costs may be almost two-fold higher among patients with persistent or recurrent angina post-PCI vs. those who become symptom-free. However, practice guideline recommendations regarding the management of patients with angina post-PCI are unclear. Gaps in evidence into the mechanisms of post-PCI angina are relevant, and more research seems warranted. The purpose of this document is to review potential mechanisms for the persistence or recurrence of angina post-PCI, propose a practical diagnostic algorithm, and summarize current knowledge gaps.

Contentious role of 'Good Adiponectin' in pulmonary and cardiovascular diseases: Is adiponectin directed therapy a boon or a bane?

After two decades of its discovery, numerous facts of adiponectin (APN) biology has been uncovered, yet, APN remains an elusive adipokine. Findings from clinical studies and animal models established APN's ameliorative role in cardiovascular disease (CVD) and pulmonary disease (PD) but the same condition is prognostic for mortality in the same set of patients which cornered APN towards a dubious state. A repertoire of mechanisms associated with the positive association of APN in both lean/cachectic or obese CVD and PD patients from past publications are evaluated. Newer pharmacological agent may be explored to regulate elevated blood APN concentration in COPD or CHF patients whereas administration of recombinant APN as well as growth hormone may augment blood APN concentration in obese subjects associated with low blood and intracellular APN concentration. However, some APN directed therapy in clinical as well as in pre-clinical setup has pronounced some contentious effects. After reviewing the mechanisms of the contentious role of APN functioning in pathologic conditions of CVD and PD in both lean and obese conditions, the authors came to conclusion that APN directed therapy may be utilized with caution keeping in mind the different age group, sex and the different CVD as well as pulmonary diseases they are suffering from.

Coronary Adventitial and Perivascular Adipose Tissue Inflammation in Patients With Vasospastic Angina

BACKGROUND

Recent studies suggested that perivascular components, such as perivascular adipose tissue (PVAT) and adventitial vasa vasorum (VV), play an important role as a source of various inflammatory mediators in cardiovascular disease.

OBJECTIVES

The authors tested their hypothesis that coronary artery spasm is associated with perivascular inflammation in patients with vasospastic angina (VSA) using ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT).

METHODS

This study prospectively examined 27 consecutive VSA patients with acetylcholine-induced diffuse spasm in the left anterior descending artery (LAD) and 13 subjects with suspected angina but without organic coronary lesions or coronary spasm. Using CT coronary angiography and electrocardiogram-gated ¹⁸F-FDG PET/CT, coronary PVAT volume and coronary perivascular FDG uptake in the LAD were examined. In addition, adventitial VV formation in the LAD was examined with optical coherence tomography, and Rho-kinase activity was measured in circulating leukocytes.

RESULTS

Patient characteristics were comparable between the 2 groups. CT coronary angiography and ECG-gated ¹⁸F-FDG PET/CT showed that coronary PVAT volume and coronary perivascular FDG uptake significantly increased in the VSA group compared with the non-VSA group. Furthermore, optical coherence tomography showed that adventitial VV formation significantly increased in the VSA group compared with the non-VSA group, as did Rho-kinase activity. Importantly, during the follow-up period with medical treatment, both coronary perivascular FDG uptake and Rho-kinase activity significantly decreased in the VSA group.

CONCLUSIONS

These results provide the first evidence that coronary spasm is associated with inflammation of coronary adventitia and PVAT, where ¹⁸F-FDG PET/CT could be useful for disease activity assessment. (Morphological and Functional Change of Coronary Perivascular Adipose Tissue in Vasospastic Angina [ADIPO-VSA Trial]; UMIN000016675).

Regional differences of fat depot attenuation using non-contrast, contrast-enhanced, and delayed-enhanced cardiac CT

BACKGROUND

Regional fat density assessed by computed tomography (CT) has been suggested as a marker of perivascular adipose tissue inflammation. Dual energy CT (DECT) allows improved tissue characterization compared to conventional CT.

PURPOSE

To explore whether DECT might aid regional fat density discrimination.

MATERIAL AND METHODS

We included patients who had completed a non-enhanced cardiac CT scan, CT coronary angiography (CTCA), and a delayed enhancement CT. Attenuation levels (Hounsfield units [HU]) were assessed at the epicardial, paracardial, visceral, and subcutaneous fat. The number of coronary segments with disease (SIS) was calculated.

RESULTS

A total of 36 patients were included in the analysis. Twenty-six (72%) patients had evidence of obstructive disease at CCTA and 25 (69%) patients had evidence of previous myocardial infarction. At non-contrast CT, we did not identify significant attenuation differences between epicardial, paracardial, subcutaneous, and visceral fat depots (-110.8 ± 9 HU, vs. -113.7 ± 9 HU, vs. -114.7 ± 8 HU, vs. -113.8 ± 11 HU, P = 0.36). Significant attenuation differences were detected between fat depots at mid and low energy levels, both at CTCA and delayed-enhancement scans ( P < 0.05 for all). Epicardial fat showed the least negative attenuation, irrespective of the acquisition mode; epicardial fat evaluated at 40 keV was related to the SIS (r = 0.37, P = 0.03).

CONCLUSIONS

In this study, regional fat depots amenable to examination during thoracic CT scans have distinctive regional attenuation values. Furthermore, such differences were better displayed using contrast-enhanced monochromatic imaging at low energy levels.

Difference in clinical presentations and related angiographic findings among early, late, and very late sirolimus-eluting stent failures requiring target lesion revascularization

BACKGROUNDS

The difference in clinical presentations (acute coronary syndrome [ACS] and stable coronary artery disease [SCAD]) and related angiographic morphologies of sirolimus-eluting stent (SES) failure requiring target lesion revascularization (TLR) during early-term (<1year), late-term (1-5years), and very late-term periods (>5years) remains unknown.

METHODS

Among 4484 lesions undergoing SES implantation, clinically-driven TLR was performed on 105 lesions during early-term, 169 lesions during late-term, and 147 lesions during very late-term period. Angiographic morphological patterns were divided into focal or non-focal patterns and stent-edge or stent-body patterns.

RESULTS

The proportion of ACS substantially increased in very late TLR lesions (57.1%) from early (40.0%, p=0.01) and late TLR lesions (36.7%, p<0.001). The proportions of both stent-edge and non-focal patterns were higher in very late TLR lesions than in early and late TLR lesions. Although the stent-edge pattern tended to be more prevalent in SCAD lesions than in ACS lesions during the early- and late-term periods, it was more frequently observed in ACS lesions than in SCAD lesions during the very late-term period (65.5% vs. 47.6%, p=0.04). The non-focal pattern was more frequent in ACS lesions than in SCAD lesions during all 3 periods. However, the proportion of the non-focal pattern in ACS lesions was extremely high during the very late-term (90.5%) compared with the early- (47.6%, p<0.001) and late-term periods (48.4%, p<0.001).

CONCLUSIONS

Stent-related ACS became more common beyond 5years after SES implantation. Stent-edge and non-focal patterns were the main angiographic morphologies of very late SES failure, particularly causing ACS.

Renal Denervation Suppresses Coronary Hyperconstricting Responses After Drug-Eluting Stent Implantation in Pigs In Vivo Through the Kidney-Brain-Heart Axis

OBJECTIVE

Drug-eluting stent-induced coronary hyperconstricting responses remain an important issue. The adventitia harbors a variety of components that potently modulate vascular tone, including sympathetic nerve fibers (SNF) and vasa vasorum. Catheter-based renal denervation (RDN) inhibits sympathetic nerve activity. We, thus, examined whether RDN suppresses drug-eluting stent-induced coronary hyperconstricting responses, and if so, what mechanisms are involved.

APPROACH AND RESULTS

Protocol 1: pigs implanted with everolimus-eluting stents into the left coronary arteries underwent coronary angiography at 1 month after implantation for assessment of coronary vasomotion and adventitial SNF formation. Drug-eluting stent-induced coronary hyperconstricting responses were significantly enhanced associated with enhanced coronary adventitial SNF and vasa vasorum formation. Protocol 2: pigs implanted with everolimus-eluting stents were randomly assigned to the RDN or sham group. The RDN group underwent renal ablation. At 1 month, RDN significantly caused marked damage of the SNF at the renal arteries without any stenosis, thrombus, or dissections. Notably, RDN significantly upregulated the expression of α₂-adrenergic receptor-binding sites in the nucleus tractus solitarius, attenuated muscle sympathetic nerve activity, and decreased systolic blood pressure and plasma renin activity. In addition, RDN attenuated coronary hyperconstricting responses to intracoronary serotonin at the proximal and distal stent edges associated with decreases in SNF and vasa vasorum formation, inflammatory cell infiltration, and Rho-kinase expression/activation. Furthermore, there were significant positive correlations between SNF and vasa vasorum and between SNF and coronary vasoconstricting responses.

CONCLUSIONS

These results provide the first evidence that RDN ameliorates drug-eluting stent-induced coronary hyperconstricting responses in pigs in vivo through the kidney-brain-heart axis.

Adiponectin, lipids and atherosclerosis

PURPOSE OF REVIEW

Adiponectin is an adipokine with anti-inflammatory, antioxidant, antiatherogenic, pro-angiogenic, vasoprotective and insulin-sensitizing properties. Several factors may influence adiponectin levels, such as genetic polymorphisms, obesity / body fat distribution, diet and exercise as well as cardiovascular risk factors such as sleep deprivation and smoking as well as medications. Adiponectin has been proposed as a potential prognostic biomarker and a therapeutic target in patients with cardiometabolic diseases.

RECENT FINDINGS

This narrative review discusses the associations of adiponectin with obesity-related metabolic disorders (metabolic syndrome, nonalcoholic fatty liver disease, hyperuricaemia and type 2 diabetes mellitus). We also focus on the links between adiponectin and lipid disorders and with coronary heart disease and noncardiac vascular diseases (i.e. stroke, peripheral artery disease, carotid artery disease, atherosclerotic renal artery stenosis, abdominal aortic aneurysms and chronic kidney disease). Further, the effects of lifestyle interventions and drug therapy on adiponectin levels are briefly reviewed.

SUMMARY

Based on available data, adiponectin represents a multifaceted biomarker that may beneficially affect atherosclerosis, inflammation and insulin resistance pathways. However, there are conflicting results with regard to the associations between adiponectin levels and the prevalence and outcomes of cardiometabolic diseases. Further research on the potential clinical implications of adiponectin in the diagnosis and treatment of such diseases is needed.