Beneficial effects of intracoronary nicorandil on microvascular dysfunction after primary percutaneous coronary intervention: demonstration of its superiority to nitroglycerin in a cross-over study. Cardiovasc Drugs Ther. 2013;27:279-287. [PMID: 23722418 DOI: 10.1007/s10557-013-6456-y]

Coronary Microcirculation: The Next Frontier in the Management of STEMI

Although the widespread adoption of timely invasive reperfusion strategies over the last two decades has significantly improved the prognosis of patients with ST-segment elevation myocardial infarction (STEMI), up to half of patients after angiographically successful primary percutaneous coronary intervention (PCI) still have signs of inadequate reperfusion at the level of coronary microcirculation. This phenomenon, termed coronary microvascular dysfunction (CMD), has been associated with impaired prognosis. The aim of the present review is to describe the collected evidence on the occurrence of CMD following primary PCI, means of assessment and its association with the infarct size and clinical outcomes. Therefore, the practical role of invasive assessment of CMD in the catheterization laboratory, at the end of primary PCI, is emphasized, with an overview of available technologies including thermodilution- and Doppler-based methods, as well as recently developing functional coronary angiography. In this regard, we review the conceptual background and the prognostic value of coronary flow reserve (CFR), index of microcirculatory resistance (IMR), hyperemic microvascular resistance (HMR), pressure at zero flow (PzF) and angiography-derived IMR. Finally, the so-far investigated therapeutic strategies targeting coronary microcirculation after STEMI are revisited.

The Importance of Integrated Regulation Mechanism of Coronary Microvascular Function for Maintaining the Stability of Coronary Microcirculation: An Easily Overlooked Perspective

Coronary microvascular dysfunction (CMD) refers to a group of disorders affecting the structure and function of coronary microcirculation and is associated with an increased risk of major adverse cardiovascular events. At present, great progress has been made in the diagnosis of CMD, but there is no specific treatment for it because of the complexity of CMD pathogenesis. Vascular dysfunction is one of the important causes of CMD, but previous reviews mostly considered microvascular dysfunction as a whole abnormality so the obtained conclusions are skewed. The coronary microvascular function is co-regulated by multiple mechanisms, and the mechanisms by which microvessels of different luminal diameters are regulated vary. The main purpose of this review is to revisit the mechanisms by which coronary microvessels at different diameters regulate coronary microcirculation through integrated sequential activation and briefly discuss the pathogenesis, diagnosis, and treatment progress of CMD from this perspective.

Nicorandil, Novel Potassium Adenosine Triphosphate Channel (K+ ATP) Opener in Ischemia With Non-Obstructive Coronary Arteries (INOCA) and Atherosclerotic Cardiovascular Disease (ASCVD): Delphi Consensus Statement

BACKGROUND

Coronary artery disease (CAD) is a significant health concern today that has assumed epidemic proportions worldwide and in India.

OBJECTIVE

The pathobiology of CAD or ischemia with non-obstructive coronary arteries disease (INOCA) in most cases involves coronary microvascular dysfunction (CMD) that often requires personalized pheno-approach based on the risk stratification and diagnostic yield, especially in patients with recurrent angina episodes. Chronic therapy with anti-anginal is often fraught with challenges of unipolar action, tolerance, and oxidative stress that precludes consistent benefits in clinical cases of CMD represented by microvascular angina (MVA). To further elucidate the clinical role and relevance of long-term vasodilator therapy, including nicorandil, a Knowledge, Attitude, and Perception (KAP) survey was planned to be conducted.

METHODS

Based on responses to the KAP survey questionnaire, Delphi-mediated graded recommendations were developed by a specialist panel as per Agency of Health Care and Quality Systems (AHRQ) criteria.

RESULTS

Management of INOCA with MVA requires a multidisciplinary approach involving non- or invasive procedures that may be relevant for persistent or refractory angina before instituting symptomatic and long-term use of nicorandil for beta-blocker intolerant and associated clinical phenotypes.

CONCLUSION

The analyses provide a real-life approach to the management of INOCA and angina non-obstructive coronary artery disease (ANOCA) with underlying CMD that may be relevant in outpatient settings in India.

Lim E, Challis BG, Park S, Izatt L, Carroll PV, Velusamy A, Hulse T, Whitelaw BC, Martin E, Rodger F, Maranian M, Clark GR, A. Akker S, Maher ER, Casey RT. Investigating the role of somatic sequencing platforms for phaeochromocytoma and paraganglioma in a large UK cohort

OBJECTIVES

Phaeochromocytomas and paragangliomas (PPGL) are rare neuroendocrine tumours with malignant potential and a hereditary basis in almost 40% of patients. Germline genetic testing has transformed the management of PPGL enabling stratification of surveillance approaches, earlier diagnosis and predictive testing of at-risk family members. Recent studies have identified somatic mutations in a further subset of patients, indicating that molecular drivers at either a germline or tumour level can be identified in up to 80% of PPGL cases. The aim of this study was to investigate the clinical utility of somatic sequencing in a large cohort of patients with PPGL in the United Kingdom.

DESIGN AND PATIENTS

Prospectively collected matched germline and tumour samples (development cohort) and retrospectively collected tumour samples (validation cohort) of patients with PPGL were investigated.

MEASUREMENTS

Clinical characteristics of patients were assessed and tumour and germline DNA was analysed using a next-generation sequencing strategy. A screen for variants within 'mutation hotspots' in 68 human cancer genes was performed.

RESULTS

Of 141 included patients, 45 (32%) had a germline mutation. In 37 (26%) patients one or more driver somatic variants were identified including 26 likely pathogenic or pathogenic variants and 19 variants of uncertain significance. Pathogenic somatic variants, observed in 25 (18%) patients, were most commonly identified in the VHL, NF1, HRAS and RET genes. Pathogenic somatic variants were almost exclusively identified in patients without a germline mutation (all but one), suggesting that somatic sequencing is likely to be most informative for those patients with negative germline genetic test results.

CONCLUSIONS

Somatic sequencing may further stratify surveillance approaches for patients without a germline genetic driver and may also inform targeted therapeutic strategies for patients with metastatic disease.

Effects of Nicorandil Administration on Infarct Size in Patients With ST-Segment-Elevation Myocardial Infarction Undergoing Primary Percutaneous Coronary Intervention: The CHANGE Trial

Background Nicorandil was reported to improve microvascular dysfunction and reduce reperfusion injury when administered before primary percutaneous coronary intervention. In this multicenter, prospective, randomized, double-blind clinical trial (CHANGE [Effects of Nicorandil Administration on Infarct Size in Patients With ST-Segment-Elevation Myocardial Infarction Undergoing Primary Percutaneous Coronary Intervention]), we investigated the effects of nicorandil administration on infarct size in patients with ST-segment-elevation myocardial infarction treated with primary percutaneous coronary intervention. Methods and Results A total of 238 patients with ST-segment-elevation myocardial infarction were randomized to receive intravenous nicorandil (n=120) or placebo (n=118) before reperfusion. Patients in the nicorandil group received a 6-mg intravenous bolus of nicorandil followed by continuous infusion at a rate of 6 mg/h. Patients in the placebo group received the same dose of placebo. The predefined primary end point was infarct size on cardiac magnetic resonance (CMR) imaging performed at 5 to 7 days and 6 months after reperfusion. CMR imaging was performed in 201 patients (84%). Infarct size on CMR imaging at 5 to 7 days after reperfusion was significantly smaller in the nicorandil group compared with the placebo (control) group (26.5±17.1 g versus 32.4±19.3 g; P=0.022), and the effect remained significant on long-term CMR imaging at 6 months after reperfusion (19.5±14.4 g versus 25.7±15.4 g; P=0.008). The incidence of no-reflow/slow-flow phenomenon during primary percutaneous coronary intervention was much lower in the nicorandil group (9.2% [11/120] versus 26.3% [31/118]; P=0.001), and thus, complete ST-segment resolution was more frequently observed in the nicorandil group (90.8% [109/120] versus 78.0% [92/118]; P=0.006). Left ventricular ejection fraction on CMR imaging was significantly higher in the nicorandil group than in the placebo group at both 5 to 7 days (47.0±10.2% versus 43.3±10.0%; P=0.011) and 6 months (50.1±9.7% versus 46.4±8.5%; P=0.009) after reperfusion. Conclusions In the present trial, administration of nicorandil before primary percutaneous coronary intervention led to improved myocardial perfusion grade, increased left ventricular ejection fraction, and reduced myocardial infarct size in patients with ST-segment-elevation myocardial infarction. Registration URL: http://www.clinicaltrials.gov. Unique identifier: NCT03445728.

COlchicine to Prevent PeriprocEdural Myocardial Injury in Percutaneous Coronary Intervention (COPE-PCI): Coronary Microvascular Physiology Pilot Substudy

Aim

In this randomized pilot trial, we aimed to assess the anti-inflammatory effect of preprocedural colchicine on coronary microvascular physiology measurements before and after PCI.

Methods

Patients undergoing PCI for stable angina (SA) or non-ST-elevation myocardial infarction (NSTEMI) were randomized to oral colchicine or placebo, 6- to 24-hours before the procedure. Strict prespecified inclusion/exclusion criteria were set to ensure all patients were given the study medication, had a PCI, and had pre- and post-PCI culprit vessel invasive coronary physiology measurements. Fractional flow reserve (FFR), Index of Microvascular Resistance (IMR), Coronary Flow Reserve (CFR), and Resistive Reserve Ratio (RRR) were measured immediately before and after PCI. CMVD was defined as any one of post-PCI IMR >32 or CFR <2 or RRR <2. High-sensitive-(hs)-troponin-I, hsCRP, and leucocyte count were measured before and 24 hours after PCI.

Results

A total of 50 patients were randomized and met the strict prespecified inclusion/exclusion criteria: 24-colchicine and 26-placebo. Pre-PCI coronary physiology measurements, hs-troponin-I, and hsCRP were similar between groups. Although numerically lower in patients given colchicine, the proportion of patients who developed CMVD was not significantly different between groups (colchicine: 10 (42%) vs placebo: 16 (62%), p=0.16). Colchicine patients had higher post-PCI CFR and RRR vs placebo (respectively: 3.25 vs 2.00, p=0.03 & 4.25 vs 2.75, p < 0.01). Neutrophil count was lower after PCI in the colchicine arm (p=0.02), and hsCRP post-PCI remained low in both treatment arms (1.0 mg/L vs 1.7 mg/L, p=0.97). Patients randomized to colchicine had significantly less PCI-related absolute hs-troponin-I change (46 ng/L vs 152 ng/L, p=0.01).

Conclusion

In this pilot randomized substudy, colchicine given 6 to 24 hours before PCI did not statistically impact the post-PCI CMVD definition used in this study, yet it did improve post-PCI RRR and CFR measurements, with less procedure-related troponin release and less inflammation.

Novel Applications for Invasive and Non-invasive Tools in the Era of Contemporary Percutaneous Coronary Revascularisation

Percutaneous coronary intervention (PCI) is an expanding treatment option for patients with coronary artery disease (CAD). It is considered the default strategy for the unstable presentation of CAD. PCI techniques have evolved over the last 4 decades with significant improvements in stent design, an increase in functional assessment of coronary lesions, and the use of intra-vascular imaging. Nonetheless, the morbidity and mortality related to CAD remain significant. Advances in technology have allowed a better understanding of the nature and progression of CAD. New tools are now available that reflect the pathophysiological changes at the level of the myocardium and coronary atherosclerotic plaque. Certain changes within the plaque would render it more prone to rupture leading to acute vascular events. These changes are potentially detected using novel tools invasively, such as near infra-red spectroscopy, or non-invasively using T2 mapping cardiovascular magnetic resonance imaging (CMR) and ¹⁸F-Sodium Fluoride positron emission tomography/ computed tomography. Similarly, changes at the level of the injured myocardium are feasibly assessed invasively using index microcirculatory resistance or non-invasively using T1 mapping CMR. Importantly, these changes could be detected immediately with the opportunity to tailor treatment to those considered at high risk. Concurrently, novel therapeutic options have demonstrated promising results in reducing future cardiovascular risks in patients with CAD. This Review article will discuss the role of these novel tools and their applicability in employing a mechanical and pharmacological treatment to mitigate cardiovascular risk in patients with CAD.

The Role of Nicorandil in the Management of Chronic Coronary Syndromes in the Gulf Region

Chronic coronary syndromes (CCS) and stable angina are a growing clinical burden worldwide. This is of particular concern in the Gulf region given its high prevalence of cardiovascular risk factors, especially diabetes mellitus and smoking. Despite recommendations on the use of first- and second-line anti-anginal medication, management challenges remain. Current guidelines for pharmacologic treatment are not determined by the range of pathophysiological mechanisms of ischaemia and consequent angina, which may occur either in isolation or co-exist. In this article, we highlight the need to improve knowledge of the epidemiology of chronic coronary syndromes in the Middle East and Gulf region, and the need for studies of stratified pharmacologic approaches to improve symptomatic angina and quality of life in the large and growing number of patients with coronary artery disease from this region. We discuss the role of nicorandil, currently recommended as a second-line anti-anginal drug in CCS patients, and suggest that this may be a particularly useful add-on therapy for patients in the Gulf region.

The effect of nicorandil in patients with cardiac syndrome X: A meta-analysis of randomized controlled trials

BACKGROUND

The prevalence of cardiac syndrome X (CSX) is considerable. Some patients show recurrent angina attacks and have a poor prognosis. However, the knowledge of CSX pathophysiological mechanism is still limited, and the treatment fails to achieve a satisfactory suppression of symptoms. Nicorandil has a beneficial effect on improving coronary microvascular dysfunction (CMD). This study aims to evaluate the clinical effects and safety of nicorandil on CSX patients.

METHODS

The Cochrane Library, Pubmed, EMBASE, ClinicalTrials.gov and 4 Chinese databases were searched to identify relevant studies. The Cochrane "Risk of bias" tool was used to assess the methodological quality of eligible studies. Meta-analysis was performed by RevMan 5.3 software. The Eggers test and meta-regression were performed by software Stata 14.0. Quality of evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

RESULTS

Twenty four randomized controlled trials (RCTs) involving 2323 patients were included. Most of the included studies were classified as having an unclear risk of bias because of poor reported methodology. The main outcomes are angina symptoms improvement, resting electrocardiogram (ECG) improvement, treadmill test result, and endothelial function. Meta-analysis showed that nicorandil had some benefit on improving angina symptoms (RR 1.24, 95% CI 1.19 to 1.29, I = 20%, P < .00001), resting ECG (RR = 1.24, 95% IC: 1.15 to 1.33, I = 0%, P < .00001), and prolonged the time to 1 mm ST-segment depression in treadmill test result (WMD = 38.41, 95% IC: 18.46 to 58.36, I = 0%, P = .0002). Besides nicorandil could reduce the level of endothelin-1 (ET-1) (SMD = -2.22, 95% IC: -2.61 to -1.83, I = 77%, P < .00001) and increase the level of nitric oxide (NO) (WMD = 27.45, 95% IC: 125.65 to 29.24, I = 81%, P < .00001). No serious adverse drug event was reported. The Eggers test showed that significant statistical publication bias was detected (Eggers test P = .000). The quality of evidence ranged from very low to low.

CONCLUSIONS

Nicorandil shows the potential of improving angina symptoms, ECG, and endothelial dysfunction in patients with CSX. However, there is insufficient evidence for the clinical benefits of nicorandil due to the very low-quality evidence.

The Potential Use of the Index of Microcirculatory Resistance to Guide Stratification of Patients for Adjunctive Therapy in Acute Myocardial Infarction

The goal of reperfusion therapies in ST-segment elevation myocardial infarction has evolved to include effective reperfusion of the microcirculation subtended by the culprit epicardial coronary artery. The index of microcirculatory resistance is measured using a pressure- and temperature-sensing coronary guidewire and quantifies microvascular dysfunction. The index of microcirculatory resistance is an independent predictor of microvascular obstruction, infarct size, and adverse clinical outcomes. It has the advantage of being immediately measurable in the catheterization laboratory, before the results of blood biomarkers or noninvasive imaging become available. This provides an opportunity for additional intervention that may alter outcomes. In this review, the authors provide a critical appraisal of the published research on the emerging role of the index of microcirculatory resistance as a tool to guide the stratification of patients for adjunctive therapeutic strategies in acute ST-segment elevation myocardial infarction.

Kir6.2-D323 and SUR2A-Q1336: an intersubunit interaction pairing for allosteric information transfer in the KATP channel complex

ATP-sensitive potassium (K_ATP) channels are widely expressed and play key roles in many tissues by coupling metabolic state to membrane excitability. The SUR subunits confer drug and enhanced nucleotide sensitivity to the pore-forming Kir6 subunit, and so information transfer between the subunits must occur. In our previous study, we identified an electrostatic interaction between Kir6 and SUR2 subunits that was key for allosteric information transfer between the regulatory and pore-forming subunit. In this study, we demonstrate a second putative interaction between Kir6.2-D323 and SUR2A-Q1336 using patch clamp electrophysiological recording, where charge swap mutation of the residues on either side of the potential interaction compromise normal channel function. The Kir6.2-D323K mutation gave rise to a constitutively active, glibenclamide and ATP-insensitive K_ATP complex, further confirming the importance of information transfer between the Kir6 and SUR2 subunits. Sensitivity to modulators was restored when Kir6.2-D323K was co-expressed with a reciprocal charge swap mutant, SUR-Q1336E. Importantly, equivalent interactions have been identified in both Kir6.1 and Kir6.2 suggesting this is a second important interaction between Kir6 and the proximal C terminus of SUR.

Correlation between intracoronary thrombus components and coronary blood flow after percutaneous coronary intervention for acute myocardial infarction at different onset time

BACKGROUND

Acute myocardial infarction (AMI) is a leading cause of mortality. Early reperfusion to restore blood flow is crucial to successful treatment. In the current reperfusion regimen, an increasing number of patients have benefited from direct percutaneous coronary intervention (PCI). In order to understand whether there is a correlation between the components of coronary thrombosis and the absence of reflow or slow blood flow after coronary stent implantation in direct PCI, we collected data on direct PCI cases in our hospital between January 2016 and November 2018.

AIM

To investigate the correlation between intracoronary thrombus components and coronary blood flow after stent implantation in direct PCI in AMI.

METHODS

We enrolled 154 patients (85 male and 69 female, aged 36–81 years) with direct PCI who underwent thrombus catheter aspiration within < 3, 3–6 or 6–12 h of onset of AMI between January 2016 and November 2018. The thrombus was removed for pathological examination under a microscope. The patients of the three groups according to the onset time of AMI were further divided into those with a white or red thrombus. The thrombolysis in myocardial infarction (TIMI) blood flow after stent implantation was recorded based on digital subtraction angiography during PCI. The number of patients with no-reflow and slow blood flow in each group was counted. Statistical analysis was performed based on data such as onset time, TIMI blood flow.

RESULTS

There were significant differences in thrombus components between the patients with acute ST-segment elevation myocardial infarction and non-ST-segment elevation myocardial infarction (P < 0.01). In the group with PCI < 3 h after onset of AMI, there was no significant difference in the incidence of no-reflow and slow-flow between the white and red thrombus groups. In the groups with PCI 3-6 and 6-12 h after onset of AMI, there was a significant difference in the incidence of no-reflow and slow-flow between the white and red thrombus groups (P < 0.01). There was a significant correlation between the onset time of AMI and the occurrences of no-reflow and slow blood flow during PCI (P < 0.01).

CONCLUSION

In direct PCI, the onset time of AMI and color of coronary thrombus are often used to predict whether there will be no reflow or slow blood flow after stent implantation.

Effect of sequential nicorandil on myocardial microcirculation and short-term prognosis in acute myocardial infarction patients undergoing coronary intervention

Background

This study aims to observe the effects of the intracoronary and peripheral venous administration of nicorandil for the postoperative myocardial microcirculation and short-term prognosis of ST-segment elevation myocardial infarction (STEMI) patients undergoing primary percutaneous coronary intervention (PPCI) treatment.

Methods

A total of 140 STEMI patients were divided into three groups according to different patterns of administration: sequential nicorandil group, intracoronary nicorandil group and control group. The main observation indexes included coronary blood flow and myocardial perfusion immediately after PPCI, while the secondary observation indexes included major adverse cardiovascular events (MACE) and left ventricular ejection fraction (LVEF) during the period of hospitalization.

Results

After PPCI, the difference in the proportion of patients with thrombolysis in myocardial infarction (TIMI) flow grade 3 among the three groups was statistically significant (P=0.036), where this proportion was higher in the sequential nicorandil group and intracoronary nicorandil group than in the control group (P=0.022 and P=0.047); The difference in corrected TIMI frame count (CTFC) among the three groups was statistically significant (P=0.022), where CTFC was lower in the sequential nicorandil group and intracoronary nicorandil group than in the control group (P=0.010, P=0.031); The differences in the proportion of patients with complete ST resolution (STR) and advancing of enzyme peak time to within 12 h between each two groups were statistically significant (P<0.001), where this proportion was the highest in the sequential nicorandil group; The difference in the CK-MB peak among the three groups was statistically significant (P=0.036), where the CK-MB peak was lower in the sequential nicorandil group than in the control group (P=0.012); The difference in the incidence of MACE between each two groups was statistically significant (P<0.001), where this incidence was the lowest in the sequential nicorandil group; The differences in the proportion of patients with advancing of enzyme peak time to within 14 h and LVEF among the three groups were not statistically significant (P=0.722 and P=0.284).

Conclusions

Compared with intracoronary use alone, the intracoronary and peripheral intravenous use of nicorandil can better improve myocardial microcirculation and short-term prognosis.

Role of TLR4/MyD88/NF-κB signaling pathway in coronary microembolization-induced myocardial injury prevented and treated with nicorandil

Coronary microembolization (CME) is a common complication during the treatment of acute coronary syndrome (ACS) and percutaneous coronary intervention (PCI). Nicorandil can be used to prevent myocardial injury after PCI to reduce the incidence of coronary no-reflow and slow flow, and play a role in myocardial protection, suggesting that its mechanism may be related to the inhibition of CME-induced inflammation of cardiomyocytes. However, the specific mechanism remains unclear. This study investigated the myocardial protective effects of nicorandil pretreatment on CME-induced myocardial injury and the specific mechanism of its inhibition of myocardial inflammation. An CME rat model exhibited CME-induced myocardial inflammation and the elevation of serum tumor necrosis factor-alpha (TNF-α) and interleukin (IL)-1β based on echocardiography, myocardial enzyme detection, hematoxylin and eosin (HE) and hematoxylin-basic fuchsin-picric acid (HBFP) stainings, ELISA, quantitative real-time PCR, and western blotting. Nicorandil treatment seven days before CME induction effectively inhibited myocardial inflammation, ameliorated myocardial injury, and improved cardiac function, mainly by inhibiting Toll-like receptor 4 (TLR4)-mediated myeloid differentiation primary response protein 88 (MyD88)-dependent nuclear factor-kappa B (NF-κB) signaling. Rat neonatal cardiomyocyte experiments further confirmed that nicorandil ameliorated lipopolysaccharide (LPS)-induced myocardial inflammation and improved cardiomyocyte survival. The specific mechanisms mainly involved the inhibition of TLR4/MyD88/NF-κB signaling and the reduction of the inflammatory cytokines TNF-α and IL-1β released from cardiomyocytes. In summary, nicorandil significantly protected cardiomyocytes from CME-induced myocardial injury mainly by inhibiting TLR4/MyD88/NF-κB signaling, thereby reducing the onset of CME-induced myocardial inflammation. This could be one of the important mechanisms for reducing postoperative myocardial injury via PCI-preoperative prophylactic treatment with nicorandil.

Protective effect of nicorandil on myocardial injury following percutaneous coronary intervention in older patients with stable coronary artery disease: Secondary analysis of a randomized, controlled trial (RINC)

Background

Our previous study examined an effect of remote ischemic preconditioning (RIPC) or intravenous nicorandil on reduction of periprocedural myocardial injury (pMI) following percutaneous coronary intervention (PCI) in patients with stable coronary artery disease (CAD). We further investigated the effect of RIPC or nicorandil on pMI in older patients.

Methods

Patients with stable CAD who planned to undergo PCI were assigned to a 1:1:1 ratio to control, intravenous nicorandil, or upper-limb RIPC groups. This substudy analyzed patients aged >65 years (n = 282) from the principal cohort. The primary outcome was the incidence of pMI following PCI. We defined pMI as an elevated level of high-sensitive cardiac troponin T or creatine kinase myocardial band 12 or 24 hours after PCI.

Results

We found that pMI following PCI was significantly reduced in the nicorandil group compared with the control group (37.2% vs. 53.7%, multiplicity-adjusted p = 0.046), but not in the RIPC group compared with the control group (43.0% vs. 53.7%, multiplicity-adjusted p = 0.245). The adjusted odds ratios (95% confidence interval) for pMI in the RIPC and nicorandil groups versus the control group were 0.63 (0.34 to 1.16) and 0.51 (0.27 to 0.96), respectively.

Conclusion

Intravenous nicorandil significantly reduces pMI following PCI in a subgroup of older patients with stable CAD. Phase 3 trials are required to validate our results.

Trial registration

UMIN Clinical Trials Registry UMIN000005607.

Nicorandil and Long-acting Nitrates: Vasodilator Therapies for the Management of Chronic Stable Angina Pectoris

Nicorandil and long-acting nitrates are vasodilatory drugs used commonly in the management of chronic stable angina pectoris. Both nicorandil and long-acting nitrates exert anti-angina properties via activation of nitric oxide (NO) signalling pathways, triggering vascular smooth muscle cell relaxation. Nicorandil has additional actions as an arterial K⁺ _ATP channel agonist, resulting in more "balanced" arterial and venous vasodilatation than nitrates. Ultimately, these drugs prevent angina symptoms through reductions in preload and diastolic wall tension and, to a lesser extent, epicardial coronary artery dilatation and lowering of systemic blood pressure. While there is some evidence to suggest a modest reduction in cardiovascular events among patients with stable angina treated with nicorandil compared to placebo, this prognostic benefit has yet to be proven conclusively. In contrast, there is emerging evidence to suggest that chronic use of long-acting nitrates might cause endothelial dysfunction and increased cardiovascular risk in some patients.

Invasive Assessment of the Coronary Microvasculature

Traditionally, invasive coronary physiological assessment has focused on the epicardial coronary artery. More recently, appreciation of the importance of the coronary microvasculature in determining patient outcomes has grown. Several invasive modalities for interrogating microvascular function have been proposed. Angiographic techniques have been limited by their qualitative and subjective nature. Doppler wire-derived coronary flow reserve has been applied in research studies, but its clinical role has been limited by its lack of reproducibility, its lack of a clear normal value, and the fact that it is not specific for the microvasculature but interrogates the entire coronary circulation. The index of microcirculatory resistance—a thermodilution-derived measure of the minimum achievable microvascular resistance—is relatively easy to measure, more reproducible, has a clearer normal value, and is independent of epicardial coronary artery stenosis. The index of microcirculatory resistance has been shown to have prognostic value in patients with ST-segment–elevation myocardial infarction and cardiac allograft vasculopathy after heart transplantation. Emerging data demonstrate its role in evaluating patients with chest pain and nonobstructive coronary artery disease. Increasingly, the index of microcirculatory resistance is used as a reference standard for invasively assessing the microvasculature in clinical trials.

Combined analysis of the safety of intra-coronary drug delivery during primary percutaneous coronary intervention for acute myocardial infarction: A study of three clinical trials

Background

The local injection of novel cardioprotective study drugs prior to percutaneous coronary intervention could cause embolisation of thrombus, resulting in increased reperfusion injury and subsequent infarct size. The aim of this study was to assess the safety of the delivery of an intracoronary therapy delivered during primary percutaneous coronary intervention for acute myocardial infarction prior to the re-establishment of thrombolysis in myocardial infarction III flow.

Methods

One hundred sixty-seven patients with acute myocardial infarction successfully reperfused through primary percutaneous coronary intervention and undergoing Cardiac MRI within the first week after reperfusion were studied. Patients either underwent the delivery of an intracoronary agent (IMP or placebo) prior to balloon dilatation (n = 80) or standard primary percutaneous coronary intervention procedure (n = 117).

Results

Baseline characteristics were similar between the two groups. There were a similar number of successful procedures (IC IMP 75 (93.8%) vs. No IMP 114, (97.4%), p = 0.374), rates of no-reflow (IC IMP 1 (1.3%) vs. No IMP 2 (1.7%), p = 0.99) and levels of ST segment resolution (88.5% IC IMP vs. No IC IMP 87.0%, p = 0.669) between the two groups. Similar levels of microvascular obstruction were seen between the two groups with a trend to reduced infarct size, and improved ejection fractions in the IMP group. Lower MACE rates were seen in the IMP group.

Conclusion

The local intracoronary infusion of potential cardioprotective agents prior to the restoration of TIMI flow in patients undergoing primary percutaneous coronary intervention for acute myocardial infarction appears to be safe and does not increase microvascular damage. This route should be considered when testing novel cardioprotective agents.

Effects of nicorandil on PI3K/Akt signaling pathway and its anti-apoptotic mechanisms in coronary microembolization in rats

Coronary microembolization (CME) is a common complication of percutaneous coronary intervention (PCI) for acute coronary syndrome. It leads to myocardial apoptosis and cardiac dysfunction. Nicorandil pretreatment can prevent PCI-related myocardial injury and reduce the incidence of no- or slow-reflow phenomena. This cardioprotective effect is probably attributable to the suppression of CME-induced cardiomyocyte apoptosis, but the specific mechanisms have not been clarified. We aimed to investigate the protective effects of nicorandil pretreatment on CME-induced myocardial injury and clarify the underlying mechanisms. In vivo studies, we used echocardiography, cardiac-enzymes measurement, hematoxylin–basic fuchsin–picric acid staining, TUNEL assay, and western blot, and found that CME significantly increased apoptotic cardiomyocytes in the infarct and peri-infarct areas in rats. The PI3K/Akt signaling pathway was involved in cardiomyocyte apoptosis. Nicorandil pretreatment given 7 days before CME effectively reduced cardiomyocyte apoptosis and myocardial injuries in rats, mainly through the activation of PI3K/Akt signaling. In vitro studies further showed that nicorandil reduced hypoxia-induced cardiomyocyte apoptosis and improved cardiomyocyte-survival rate. The PI3K-specific inhibitor LY294002 reduced these cardioprotective effects, indicating that they were attributable to the activation of the PI3K/Akt signaling pathway. In conclusion, nicorandil has significant cardioprotective effects in CME mainly through the activation of the PI3K/Akt signaling pathway and reduction of CME-induced cardiomyocyte apoptosis. Our findings may provide important support for the pre-PCI use of nicorandil to reduce post-PCI myocardial injuries.

Cardioprotective Effects of Nicorandil on Coronary Heart Disease Patients Undergoing Elective Percutaneous Coronary Intervention

Background

Nicorandil is a nicotinamide ester commonly prescribed for treatment of patients with coronary heart disease (CHD). In the present study, we aimed to explore the cardioprotective effects of nicorandil on CHD patients undergoing elective percutaneous coronary intervention (PCI).

Material/Methods

One hundred patients with CHD undergoing PCI were randomly divided into a control group (n=48) and a nicorandil group (n=52). Patients in the control group received traditional therapy, and while patients in the nicorandil group received nicorandil before PCI in addition to the traditional therapy. After PCI, all patients underwent coronary angiogram, and TIMI frame count (TFC) was calculated. Plasma levels of cardiac troponin I (cTnI), creatine kinase-MB (CK-MB), myeloperoxidase (MPO), and malondialdehyde (MDA) were determined before and at 6, 18, and 24 h after PCI. Moreover, systolic blood pressure (SBP), mean blood pressure (DBP), heart rate (HR), and left ventricular ejection fractions (LVEF) were recorded before and 3 months after PCI.

Results

There was a significant difference in the rate of no-reflow (P=0.036) between the 2 groups. The blood frames and levels of cTnI, CK-MB, MPO, and MDA in the nicorandil group were significantly decreased compared to the control group (all P<0.05). Moreover, administration of nicorandil markedly decreased SBP, MBP, and HR, but obviously increased LVEF at 3 months after PCI (P<0.05 or P<0.01).

Conclusions

Nicorandil exerts cardioprotective effects on CHD patients undergoing elective PCI by decreasing PCI-related myocardial injury and rate of no-reflow and improvement of LVEF.

The clinical effect of nicorandil on perioperative myocardial protection in patients undergoing elective PCI: A Systematic Review and Meta-Analysis

Many scholars have studied the effect of nicorandil on perioperative myocardial protection in patients undergoing elective percutaneous coronary intervention (PCI), but results are inconsistent. Therefore, we performed this meta-analysis. Finally, 16 articles, including 1616 patients, were included into this meta-analysis. Meta-analysis results showed that: (1) Nicorandil can reduce the level of CK-MB after PCI, including at 6 hours, 12 hours, 18 hours and 24 hours. (2) Nicorandil can reduce the level of TnT after PCI, including at 6 hours, 12 hours, 18 hours and 24 hours. (3) Nicorandil can reduce the incidence of adverse reactions after PCI. (4) Nicorandil cannot reduce the level of MVP after PCI, including at 12 hours and 24 hours. (5) Subgroup analysis showed that nicorandil can reduce CK-MB and TnT level at 24 hours after PCI for Chinese's population (P < 0.05), but can not reduce CK-MB and TnT level at 24 hours after PCI for non Chinese's population (P > 0.05). Our meta-analysis indicate that nicorandil can reduce myocardial injury and reduce the incidence of adverse reaction caused by PCI for Chinese's population, but is not obvious for non Chinese's population. However, this conclusion still needs to be confirmed in the future.

Clinical benefit of adenosine as an adjunct to reperfusion in ST-elevation myocardial infarction patients: An updated meta-analysis of randomized controlled trials

BACKGROUND

Adenosine administered as an adjunct to reperfusion can reduce coronary no-reflow and limit myocardial infarct (MI) size in ST-segment elevation myocardial infarction (STEMI) patients. Whether adjunctive adenosine therapy can improve clinical outcomes in reperfused STEMI patients is not clear and is investigated in this meta-analysis of 13 randomized controlled trials (RCTs).

METHODS

We performed an up-to-date search for all RCTs investigating adenosine as an adjunct to reperfusion in STEMI patients. We calculated pooled relative risks using a fixed-effect meta-analysis assessing the impact of adjunctive adenosine therapy on major clinical endpoint including all-cause mortality, non-fatal myocardial infarction, and heart failure. Surrogate markers of reperfusion were also analyzed.

RESULTS

13 RCTs (4273 STEMI patients) were identified and divided into 2 subgroups: intracoronary adenosine versus control (8 RCTs) and intravenous adenosine versus control (5 RCTs). In patients administered intracoronary adenosine, the incidence of heart failure was significantly lower (risk ratio [RR] 0.44 [95% CI 0.25-0.78], P=0.005) and the incidence of coronary no-reflow was reduced (RR for TIMI flow<3 postreperfusion 0.68 [95% CI 0.47-0.99], P=0.04). There was no difference in heart failure incidence in the intravenous adenosine group but most RCTs in this subgroup were from the thrombolysis era. There was no difference in non-fatal MI or all-cause mortality in both subgroups.

CONCLUSION

We find evidence of improved clinical outcome in terms of less heart failure in STEMI patients administered intracoronary adenosine as an adjunct to reperfusion. This finding will need to be confirmed in a large adequately powered prospective RCT.

Stable Ischemic Heart Disease

Classical angina refers to typical substernal discomfort triggered by effort or emotions, relieved with rest or nitroglycerin. The well-accepted pathogenesis is an imbalance between oxygen supply and demand. Goals in therapy are improvement in quality of life by limiting the number and severity of attacks, protection against future lethal events, and measures to lower the burden of risk factors to slow disease progression. New pathophysiological data, drugs, as well as conceptual and technological advances have improved patient care over the past decade. Behavioral changes to improve diets, increase physical activity, and encourage adherence to cardiac rehabilitation programs, are difficult to achieve but are effective.

Evaluation of Microvascular Disease and Clinical Outcomes

Although coronary microcirculatory dysfunction occurs in numerous cardiac conditions and influences prognosis, it has been largely ignored in clinical practice due to the lack of adequate methods for its assessment. Microcirculatory dysfuntion may result from a variety of causes, including structural remodelling (arterioles or capillaries), dysregulation (paradoxical arteriolar vasoconstriction), hypersensitivity to vasoactive factors or adrenergic drive, and extravascular compression of collapsable elements. Thus, the selection of a method to interrogate coronary microcirculation should be based on the suspected cause of dysfunction. This article reviews such assessment tools and their prognostic information.

The effects of nicorandil on microvascular function in patients with ST segment elevation myocardial infarction undergoing primary PCI

Background

Nicorandil, as a selective potassium channel opener, has dual action including coronary and peripheral vasodilatation and cardioprotective effect through ischemic preconditioning. Considering those characteristics, nicorandil was suggested to reduce the degree of microvascular dysfunction.

Methods

Thirty-two patients with ST-elevation myocardial infarction undergoing primary percutaneous coronary intervention (pPCI) were included in the study. Index of microvascular resistance (IMR) was measured in all patients immediatelly after pPCI before the after administration of Nicorandil. ST segment resolution was monitored before intervention and 60 min after terminating the procedure. Echocardiographic evaluation of myocardial function and transthoracic Doppler derived Coronary flow reserve (CFR) of infarct related artery (IRA) was performed during hospitalization and 3 months later.

Results

IMR was significantly lower after administration of Nicorandil (9.9 ± 3.7 vs. 14.1 ± 5.1, p < 0.001). There was significant difference in ST segment elevation before and after primary PCI with administration of Nicorandil (6.9 ± 3.7 mm vs. 1.6 ± 1.6 mm, p < 0.001). Transthoracic Doppler CFR measurement improved after 3 months (2.69 ± 0.38 vs. 2.92 ± 0.54, p = 0.021), as well as WMSI (1.14 ± 0.17 vs. 1.07 ± 0.09, p = 0.004).

Conclusion

Intracoronary Nicorandil administration after primary PCI significantly decreases IMR, resulting in improved CFR and ventricular function in patients with STEMI undergoing primary PCI.

Stable ischemic heart disease

Classical angina refers to typical substernal discomfort triggered by effort or emotions, relieved with rest or nitroglycerin. The well-accepted pathogenesis is an imbalance between oxygen supply and demand. Goals in therapy are improvement in quality of life by limiting the number and severity of attacks, protection against future lethal events, and measures to lower the burden of risk factors to slow disease progression. New pathophysiological data, drugs, as well as conceptual and technological advances have improved patient care over the past decade. Behavioral changes to improve diets, increase physical activity, and encourage adherence to cardiac rehabilitation programs, are difficult to achieve but are effective.

Increased hyperaemic coronary microvascular resistance adds to the presence of myocardial ischaemia

AIMS

It has been argued that hyperaemic microvascular resistance (HMR), defined as the ratio of mean distal coronary pressure to flow velocity, is overestimated in the presence of a coronary stenosis compared to actual microvascular resistance (MR), due to neglecting collateral flow. We aimed to test the hypothesis that HMR allows accurate identification of microvascular functional abnormalities by evaluating the association between high or low HMR and the presence of myocardial ischaemia on non-invasive stress testing.

METHODS AND RESULTS

Myocardial perfusion scintigraphy was performed in 228 patients, with 299 lesions to identify reversible myocardial ischaemia. Intracoronary distal pressure and flow velocity were assessed during adenosine-induced hyperaemia (20-40 µg, intracoronary) to determine hyperaemic stenosis resistance (HSR) and HMR. HMR >1.9 mmHg/cm/s was defined as high. The diagnostic odds ratio (OR) for myocardial ischaemia for lesions associated with high compared to low HMR was 2.6 (95% confidence interval [CI]: 1.5-4.4; p<0.001) overall, 3.3 (95% CI: 1.2-9.0; p=0.02) for lesions with HSR >0.8 mmHg/cm/s, and 1.3 (95% CI: 0.6-2.9; p=0.52) for lesions with HSR ≤0.8 mmHg/cm/s.

CONCLUSIONS

The increased risk of myocardial ischaemia in the presence of high HMR, uncorrected for collateral flow, demonstrates that HMR is reflective of an increase in actual MR, identifying pertinent pathophysiological alterations in the microvasculature.

Cardioprotective effects of single oral dose of nicorandil before selective percutaneous coronary intervention

Objective:

Nicorandil, an opener of ATP-sensitive K+ channels, was used to treat angina in patients with coronary artery disease. In this study, we aim to investigate the cardioprotective effects of single oral dose of nicorandil in patients undergoing selective percutaneous coronary intervention (PCI).

Methods:

One hundred and thirty-eight patients with acute coronary syndrome undergoing PCI from July 2011 to October 2012 were randomly divided into control group (group 1, n=47), 10 mg oral nicorandil group (group 2, n=45), and 20 mg oral nicorandil group (group 3, n=46) about 2 hours before procedure, respectively. Cardiac troponin I (cTnI) levels were determined at 20 ~ 24 hours after PCI.

Results:

There was a significant difference in the rate of any cTnI elevation among the three groups (group 1: 36.17%, group 2: 20.00%, group 3: 15.22%, p=0.0176). With respect to the frequency of cTnI elevation ≥3 and 5×the upper limit of normal (ULN), there also had statistical difference among the three groups (17.02% in group 1, 8.89% in group 2, and 4.35% in group 3, respectively for cTnI elevation ≥3× ULN, p=0.0428; 12.77% in group 1, 6.67% in group 2, and 2.17% in group 3, respectively, for cTnI elevation ≥5× ULN, p=0.0487). Logistic regression analysis showed that LVEF (OR=0.915, 95% CI=0.853-0.981) and the use of nicorandil (OR=0.516, 95% CI=0.267-0.996) before PCI were independent protective factors of myocardial injury.

Conclusion:

Single oral dose of nicorandil (10 mg, 20 mg) 2 hours before the PCI procedure could decrease the incidence of peri-procedure myocardial injury and PCI-related myocardial infarction.