Nicorandil versus isosorbide dinitrate as adjunctive treatment to direct balloon angioplasty in acute myocardial infarction

Cardioprotective and Antianginal Efficacy of Nicorandil: A Comprehensive Review

ABSTRACT

Angina pectoris remains a significant burden despite advances in medical therapy and coronary revascularization. Many patients (up to 30%) with angina have normal coronary arteries, with coronary microvascular disease and/or coronary artery vasospasm being major drivers of the myocardial demand-supply mismatch. Even among patients revascularized for symptomatic epicardial coronary stenosis, recurrent angina remains highly prevalent. Medical therapy for angina currently centers around 2 disparate goals, viz secondary prevention of hard clinical outcomes and symptom control. Vasodilators, such as nitrates, have been first-line antianginal agents for decades, along with beta-blockers and calcium channel blockers. However, efficacy in symptoms control is heterogenous, depending on underlying mechanism(s) of angina in an individual patient, often necessitating multiple agents. Nicorandil (NCO) is an antianginal agent first discovered in the late 1970s with a uniquely dual mechanism of action. Like a typical nitrate, it mediates medium-large vessel vasodilation through nitric oxide. In addition, NCO has adenosine triphosphate (ATP)-dependent potassium channel agonist activity (K ATP ), mediating microvascular dilatation. Hence, it has proven effective in both coronary artery vasospasm and coronary microvascular disease, typically challenging patient populations. Moreover, emerging evidence suggests that cardiomyocyte protection against ischemia through ischemic preconditioning may be mediated through K ATP agonism. Finally, there is now fairly firm evidence in favor of NCO in terms of hard event reduction among patients with stable coronary artery disease, following myocardial infarction, and perhaps even among patients with congestive heart failure. This review aims to summarize the mechanism of action of NCO, its efficacy as an antianginal, and current evidence behind its impact on hard outcomes. Finally, we review other cardiac and emerging noncardiac indications for NCO use.

Clinical outcomes of nicorandil administration in patients with acute ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Primary percutaneous coronary intervention is the treatment of choice in ST-segment elevation myocardial infarction and no-reflow phenomenon is still an unsolved problem.

METHODS

We searched PubMed, EmBase, and Cochrane Central Register of Controlled Trials for relevant randomized controlled trials. The primary endpoint was the incidence of major adverse cardiac events and the secondary endpoint was the incidences of no-reflow phenomenon and complete resolution of ST-segment elevation.

RESULTS

Eighteen randomized controlled trials were enrolled. Nicorandil significantly reduced the incidence of no-reflow phenomenon (OR, 0.46; 95% CI, 0.36-0.59; P < 0.001; I² = 0%) and major adverse cardiac events (OR, 0.42; 95% CI, 0.27-0.64; P < 0.001; I² = 52%). For every single outcome of major adverse cardiac events, only heart failure and ventricular arrhythmia were significantly improved with no heterogeneity (OR, 0.36; 95% CI, 0.23-0.57, P < 0.001; OR, 0.43; 95% CI, 0.31-0.60, P < 0.001 respectively). A combination of intracoronary and intravenous nicorandil administration significantly reduced the incidence of major adverse cardiac events with no heterogeneity (OR, 0.24; 95% CI, 0.13-0.43, P < 0.001; I² = 0%), while a single intravenous administration could not (OR, 0.66; 95% CI, 0.40-1.06, P = 0.09; I² = 52%).

CONCLUSIONS

Nicorandil can significantly improve no-reflow phenomenon and major adverse cardiac events in patients undergoing primary percutaneous coronary intervention. The beneficial effects on major adverse cardiac events might be driven by the improvements of heart failure and ventricular arrhythmia. A combination of intracoronary and intravenous administration might be an optimal usage of nicorandil.

Effects of Intracoronary Nicorandil on Myocardial Microcirculation and Clinical Outcomes in Patients with Acute Myocardial Infarction: A Meta-Analysis of Randomized Controlled Trials

BACKGROUND

The amelioration of myocardial reperfusion in patients with acute myocardial infarction (AMI) undergoing primary percutaneous coronary intervention (PPCI) remains a significant issue.

OBJECTIVE

We conducted a meta-analysis of randomized controlled trials (RCTs) to better assess the effects of intracoronary nicorandil administration on myocardial microcirculation and clinical outcomes in these patients.

METHODS

The meta-analysis was performed according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement. A literature search was performed in the PubMed, Embase, Cochrane Library, and Web of Science databases up to April 2019, with no time or language limitations. Pooled risk ratios (RRs) were calculated to evaluate the treatment effects.

RESULTS

Seven RCTs involving a total of 562 patients were included. Compared with control, intracoronary nicorandil significantly reduced the incidence of thrombolysis in myocardial infarction (TIMI) grade ≤ 2 (RR 0.349; 95% confidence interval [CI] 0.199-0.611; P < 0.001) and TIMI myocardial perfusion grade ≤ 2 (RR 0.611; 95% CI 0.438-0.852; P = 0.004) and was associated with higher complete ST-segment resolution rates (RR 1.326; 95% CI 1.090-1.614; P = 0.005). However, no significant benefits were observed on clinical outcomes, including death (RR 0.370; 95% CI 0.085-1.618; P = 0.187), recurrent myocardial infarction (RR 0.507; 95% CI 0.156-1.655; P = 0.261), heart failure (RR 0.528; 95% CI 0.224-1.247; P = 0.145), and target lesion/vessel revascularization (RR 1.109; 95% CI 0.553-2.224; P = 0.770).

CONCLUSIONS

Intracoronary nicorandil can significantly improve myocardial microcirculation in patients with AMI undergoing PPCI, but it failed to offer clinically significant benefits.

Nicorandil prior to primary percutaneous coronary intervention improves clinical outcomes in patients with acute myocardial infarction: a meta-analysis of randomized controlled trials

Background: Nicorandil prior to reperfusion by primary percutaneous coronary intervention (PCI) in patients with ST-segment elevated myocardial infarction (STEMI) has been suggested to be beneficial. However, results of previous randomized controlled trials (RCTs) were not consistent. We aimed to perform a meta-analysis to systematically evaluate the effect of periprocedural nicorandil in these patients. Methods: Related studies were obtained by searching PubMed, Embase and Cochrane's Library. Effects of perioperative nicorandil on the incidence of no-reflow phenomenon (NRP), corrected thrombolysis in myocardial infarction (TIMI) frame count (CTFC), wall motion score (WMS), left ventricular ejection fraction (LVEF), heart failure (HF) exacerbation of rehospitalization and incidence of major cardiovascular adverse events (MACE) were analyzed. Results: Eighteen RCTs with 2,055 patients were included. Treatment of nicorandil prior to PCI significantly reduced the incidence of NRP (risk ratio [RR]: 0.47, P<0.001), and reduced CTFC (weighed mean difference [WMD]: -4.54, P<0.001) immediately after PCI. Moreover, although nicorandil did not significantly affect WMS (WMD: 0.04, P=0.91), treatment of nicorandil significantly increased LVEF in STEMI patients undergoing primary PCI (WMD: 1.89%, P<0.001). In addition, nicorandil significantly reduced the risk of HF exacerbation or rehospitalization (RR: 0.44, P=0.001) and the incidence of MACE (RR: 0.68, P<0.001). Further analyses showed that effects of nicorandil on LVEF, HF exacerbation and MACE were consistent within one month after PCI and during follow-up. Conclusions: Periprocedural nicorandil improves coronary blood flow, cardiac systolic function and prognosis in STEMI patients receiving primary PCI.

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.

Effects of Propranolol and Verapamil on Changes in TQ and ST Segment Potentials During Graded Coronary Flow Reduction in a Porcine Myocardial Ischemia Model

Acute myocardial ischemia causes TQ depression and ST elevation. However, the effects of cardioprotective drugs such as β-blockers and Ca⁺⁺-antagonists on the extent of TQ depression, ST elevation, and myocardial ischemic injury are not fully understood.We created a carotid-coronary shunt in 30 pigs, and extracellular K⁺ ([K⁺]_e), TQ, and ST segments were recorded simultaneously with K⁺-selective plunge electrodes placed in the left anterior descending artery (LAD) distribution during graded LAD flow reduction before and after administration of propranolol or verapamil. Unipolar DC-coupled electrograms were recorded from the reference pole of the K⁺-selective plunge electrodes. The microvolt readings from the K⁺-selective electrodes were converted to [K⁺]_e and then to the changes in potassium equilibrium potential (ΔE_K). The shunted LAD flow was reduced in a stepwise fashion at 5-minute intervals.segment depression at the similar ΔE_K was not affected by propranolol or verapamil. However, ST segment elevation was reduced by propranolol but exacerbated by verapamil at the similar ΔE_K.TQ-ST changes recorded by AC coupled ECG are not a reliable index of ischemia and therefore cannot be used to evaluate the effects of drugs that might affect the electrophysiologic properties of ischemic myocardium.

Intracoronary administration of anisodamine and nicorandil in individuals undergoing primary percutaneous coronary intervention for acute inferior myocardial infarction: A randomized factorial trial

In acute inferior myocardial infarction (AIMI), numerous conventional drugs that are used to improve the myocardial microcirculation can significantly reduce blood pressure (BP) and coronary perfusion pressure, aggravate bradyarrhythmia and cause a deterioration in the hemodynamic state of the whole body, which greatly limits the application of these drugs in clinical settings. The aim of the present study was to assess the effect of anisodamine and nicorandil regimens on the prevention of no-reflow (NR) and the amelioration of myocardial reperfusion in patients with AIMI undergoing primary percutaneous coronary intervention (PCI). A total of 104 consecutive patients with AIMI were included in this study and randomly assigned to one of four groups: A (control group), B (anisodamine group), C (nicorandil group) and D (anisodamine and nicorandil group). Patients underwent PCI via transradial artery access and the angiographic results were evaluated. Coronary diastolic BP (DBP) and systolic and mean BPs were measured by invasive catheterization. The primary end-point was a post-PCI Thrombolysis In Myocardial Infarction (TIMI) myocardial perfusion grade (TMPG) of 3. Composite end-points (mortality + new MI + target vessel revascularization) were evaluated during the hospital stay and 30 days after discharge. Following the procedure, the proportion of patients achieving TMPG 3 was significantly higher in group D than that in the other groups (P=0.014); furthermore, the incidence of a postprocedural TIMI score of 3 was the highest in group D. Three days after the procedure, the peak creatine kinase-MB and cardiac troponin I levels were the lowest and the left ventricular ejection fraction was the highest in group D. A thrombus score of 3/4 and low DBP were the independent risk factors for poor myocardial reperfusion (expressed as TMPG <3), while 2 mg anisodamine plus 2 mg nicorandil prior to PCI was protective for optimal myocardial reperfusion following the procedure. The combination of anisodamine and nicorandil can effectively ameliorate myocardial reperfusion and protect cardiac function in patients with AIMI undergoing primary PCI.

All-cause mortality and cardiovascular events with nicorandil in patients with IHD: systematic review and meta-analysis of the literature

BACKGROUND

Nicorandil is able to protect the cardiomyocytes from ischemic damage, but clear benefits of nicorandil in all-cause mortality and cardiovascular events were not consistently reported in patients with ischemic heart disease (IHD).

MATERIALS AND RESULTS

Cochrane, PubMed, EMBASE, CBM, CNKI and Wangfang databases were searched for randomized controlled trials. Data on all-cause mortality and cardiovascular events were collected. Nicorandil groups were pooled to perform a comparison with control groups and to get the pooled odds ratios (ORs) and associated 95% confidence intervals (CIs) for all-cause mortality, relative risks (RRs), and associated 95% CIs for cardiovascular events. STATA 11.0 software was used for all-cause mortality and cardiovascular events statistics. We retrieved 17 randomized controlled studies enrolling a total of 7305 patients. The addition of nicorandil treatment significantly reduced cardiovascular events (13.83% versus 18.01%; RR, 0.77; 95% CI, 0.69 to 0.86). No differences in all-cause mortality (3.83% versus 4.70%; OR, 0.81; 95% CI, 0.64 to 1.02), and repeat revascularization rate (13.06% versus 13.54%; RR, 0.95; 95% CI, 0.70 to 1.29) were observed. There was a weak linear association between cardiovascular events and nicorandil in IHD with diabetes (P=0.099).

CONCLUSIONS

The results suggest that nicorandil as an adjunct therapy to IHD is associated with reduced cardiovascular events in patients with IHD.

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.

A case of vasospastic angina in which the ergonovine provocation test with intracoronary isosorbide dinitrate and nicorandil was effective in the diagnosis of microvascular spasm

A 60-year-old man was admitted with early morning angina while at rest. Coronary angiogram revealed no organic lesions; therefore, a spasm provocation test with ergonovine was performed. Administration of intracoronary ergonovine induced total occlusion of the right coronary artery. The induced total occlusion improved but coronary flow velocity remained severely reduced and chest discomfort with ST-T changes in ECG remained in spite of repeated administration of isosorbide dinitrate (ISDN). Intracoronary administration of nicorandil following ISDN alleviated the chest discomfort, normalized the ST-T change in ECG, and improved the coronary flow. This suggested that microvascular spasm and the epicardial spasm were not relieved by ISDN but by nicorandil. Intracoronary nicorandil injection following ISDN administration may be useful for the diagnosis of microvascular spasm in the ergonovine provocation test.

No-Reflow Phenomenon

No-reflow is responsible for 40% of the primary percutaneous coronary intervention without complete myocardial reperfusion despite successful reopening of the infarct-related artery. This review describes the main pathophysiological mechanisms of no-reflow, its clinical manifestation, including the strong association with increased in-hospital mortality, malignant arrhythmias, and cardiac failure as well as the diagnostic methods. The latter ranges from simple angiographic thrombolysis in myocardial infarction grade score to more complex angiographic indexes, imaging techniques such as myocardial contrast echo or cardiac magnetic resonance, and surrogate clinical end points such as ST-segment resolution. This review also summarizes the strategies of prevention and treatment of no-reflow, considering the most recent studies results regarding medical therapy and devices.

Management of the no-reflow phenomenon

The lack of reperfusion of myocardium after prolonged ischaemia that may occur despite opening of the infarct-related artery is termed "no reflow". No reflow or slow flow occurs in 3-4% of all percutaneous coronary interventions, and is most common after emergency revascularization for acute myocardial infarction. In this setting no reflow is reported to occur in 30% to 40% of interventions when defined by myocardial perfusion techniques such as myocardial contrast echocardiography. No reflow is clinically important as it is independently associated with increased occurrence of malignant arrhythmias, cardiac failure, as well as in-hospital and long-term mortality. Previously the no-reflow phenomenon has been difficult to treat effectively, but recent advances in the understanding of the pathophysiology of no reflow have led to several novel treatment strategies. These include prophylactic use of vasodilator therapies, mechanical devices, ischaemic postconditioning and potent platelet inhibitors. As no reflow is a multifactorial process, a combination of these treatments is more likely to be effective than any of these alone. In this review we discuss the pathophysiology of no reflow and present the numerous recent advances in therapy for this important clinical problem.

Cardioprotection in the clinical setting-lessons from J-WIND studies

INTRODUCTION

Both prevention and attenuation of ischemic heart disease are important issues, and there are three different strategies to save patients from the deleterious sequelae of ischemic injury. The first strategy is to remove the causes of ischemic heart disease; the second is to attenuate on-going ischemic and reperfusion injury; the third is to prevent the progression of cardiac remodeling and chronic heart failure following ischemic injury.

EVIDENCE AND DISCUSSION

For prevention of acute myocardial infarction, it is widely accepted to treat high risk patients with aspirin and/or statins. On the other hand, several medications such as angiotensin converting enzyme inhibitors, aldosterone receptor antagonists and beta blockers have been used for the prevention of post-infarction heart failure in patients who have suffered from an acute myocardial infarction. However, at present we do not have an adjunctive drug therapy to reduce infarct size in the acute phase in patients with myocardial infarction. Recently, the J-WIND trials suggested that an infusion of human atrial natriuretic peptide in the acute phase and oral administration of nicorandil in the chronic phase of infarction result in a better outcome in patients with a myocardial infarction. In this article we propose potential mechanisms for cardioprotection in patients with an acute myocardial infarction.

Diabetes mellitus as a predictor of retinopathy associated with acute myocardial infarction

BACKGROUND

A unique transient retinopathy characterized by soft exudates around the optic disc after percutaneous coronary intervention (PCI) for acute myocardial infarction (AMI) has been reported, so in the present study the risk factors for retinopathy associated with AMI (RAMI) were investigated.

METHODS AND RESULTS

The study group comprised 62 patients with their first AMI who underwent successful PCI within 24 h of onset (48 men, 14 women; age 63 +/-10 years). The fundus of each eye was assessed on days 3-5, and again at 4 weeks after AMI onset. New soft exudates developed in 29 patients (47%) at 4 weeks. The frequency of diabetes mellitus (DM), and the hemoglobin A(1c) and peak creatine kinase concentrations were higher in patients with than in those without RAMI (55% vs 21%, P=0.008; 7.0 +/-2.0% vs 5.9 +/-1.4%, P=0.013; and 3,428 +/-2,210 IU/L vs 2,352 +/-1,652 IU/L, P=0.036, respectively). Multivariate analysis identified DM as an independent predictive factor for the occurrence of RAMI (odds ratio, 6.60; 95% confidence interval, 1.68-25.90; P=0.007).

CONCLUSIONS

DM might be a risk factor for RAMI.

Intracoronary boluses of adenosine and sodium nitroprusside in combination reverses slow/no-reflow during angioplasty: a clinical scenario of ischemic preconditioning

No or slow reflow following percutaneous coronary intervention (PCI), despite the presence of a patent epicardial vessel, is a serious complication resulting in increased morbidity and mortality. In the present study, we have evaluated the combination therapy of adenosine and sodium nitroprusside administered as sequential intracoronary (IC) boluses on no-reflow during PCI. Seventy-five high risk acute coronary syndrome patients who underwent PCI with evidence of initial less than TIMI (thrombolysis in myocardial infarction) III flow or developed deterioration in TIMI flow during the procedure were randomized to prophylactic administration of multiple boluses of IC saline solution, adenosine (12 microg/bolus) or the combination of adenosine (12 microg/bolus) and sodium nitroprusside (50 microg/bolus), sequentially. Assessment of TIMI and the TMP (tissue myocardial perfusion) grade was done and major adverse cardiac events (MACE) were assessed at the end of 6 months. Slow or no-reflow was persistent in 70% patients receiving saline solution, 31% patients receiving adenosine, and 4% patient receiving the combination. IC injection with saline solution did not produce improvement in TIMI flow or TMP grade. IC injection with combination resulted in greater improvement of TIMI flow and TMP grade. The crossover of patients with no-reflow in saline solution group or adenosine with combination treatment was associated with reestablishment of TIMI II in 4 and TIMI III in 20 patients. Our data suggest that combination therapy of adenosine and nitroprusside is safe and provides better improvement in coronary flow and MACE as compared with IC adenosine alone in cases of impaired flow during coronary interventions.

Nitric Oxide Inhalation Improves Microvascular Flow and Decreases Infarction Size After Myocardial Ischemia and Reperfusion

OBJECTIVES

The purpose of this study was to test if nitric oxide (NO) could improve microvascular perfusion and decrease tissue injury in a porcine model of myocardial ischemia and reperfusion (I/R).

BACKGROUND

Inhaled NO is a selective pulmonary vasodilator with biologic effects in remote vascular beds.

METHODS

In 37 pigs, the midportion of the left anterior descending coronary artery was occluded for 50 min followed by 4 h of reperfusion. Pigs were treated with a saline infusion (control; n = 14), intravenous nitroglycerin (IV-NTG) at 2 microg/kg/min (n = 11), or inhaled nitric oxide (iNO) at 80 parts per million (n = 12) beginning 10 min before balloon deflation and continuing throughout reperfusion.

RESULTS

Total myocardial oxidized NO species in the infarct core was greater in the iNO pigs than in the control or IV-NTG pigs (0.60 +/- 0.05 nmol/mg tissue vs. 0.40 +/- 0.03 nmol/mg tissue and 0.40 +/- 0.02 nmol/mg tissue, respectively; p < 0.01 for both). Infarct size, expressed as percentage of left ventricle area at risk (AAR), was smaller in the iNO pigs than in the control or IV-NTG pigs (31 +/- 6% AAR vs. 58 +/- 7% AAR and 46 +/- 7% AAR, respectively; p < 0.05 for both) and was associated with less creatine phosphokinase-MB release. Inhaled NO improved endocardial and epicardial blood flow in the infarct zone, as measured using colored microspheres (p < 0.001 vs. control and IV-NTG). Moreover, NO inhalation reduced leukocyte infiltration, as reflected by decreased cardiac myeloperoxidase activity (0.8 +/- 0.2 U/mg tissue vs. 2.3 +/- 0.8 U/mg tissue in control and 1.4 +/- 0.4 U/mg tissue in IV-NTG; p < 0.05 for both) and decreased cardiomyocyte apoptosis in the infarct border zone.

CONCLUSIONS

Inhalation of NO just before and during coronary reperfusion significantly improves microvascular perfusion, reduces infarct size, and may offer an attractive and novel treatment of myocardial infarction.

Reperfusion injury as a therapeutic challenge in patients with acute myocardial infarction

Cardiomyocyte death secondary to transient ischemia occurs mainly during the first minutes of reperfusion, in the form of contraction band necrosis involving sarcolemmal rupture. Cardiomyocyte hypercontracture caused by re-energisation and pH recovery in the presence of impaired cytosolic Ca(2+) control as well as calpain-mediated cytoskeletal fragility play prominent roles in this type of cell death. Hypercontracture can propagate to adjacent cells through gap junctions. More recently, opening of the mitochondrial permeability transition pore has been shown to participate in reperfusion-induced necrosis, although its precise relation with hypercontracture has not been established. Experimental studies have convincingly demonstrated that infarct size can be markedly reduced by therapeutic interventions applied at the time of reperfusion, including contractile blockers, inhibitors of Na(+)/Ca(2+) exchange, gap junction blockers, or particulate guanylyl cyclase agonists. However, in most cases drugs for use in humans have not been developed and tested for these targets, while the effect of existing drugs with potential cardioprotective effect is not well established or understood. Research effort should be addressed to elucidate the unsolved issues of the molecular mechanisms of reperfusion-induced cell death, to identify and validate new targets and to develop appropriate drugs. The potential benefits of limiting infarct size in patients with acute myocardial infarction receiving reperfusion therapy are enormous.

Coronary interventions and their impact on post myocardial infarction survival

Rapid reestablishment of infarct vessel patency and microvascular flow provides the best opportunity for minimizing mortality in the patient post myocardial infarction (MI). Early infarct artery patency can be restored by thrombolysis, primary angioplasty, or facilitated percutaneous coronary intervention (PCI). In comparative studies, primary angioplasty offers a greater mortality benefit than thrombolysis in patients with acute MI. Short-term rates of mortality and stroke were significantly lower in patients receiving primary angioplasty compared with thrombolysis, as was the risk of nonfatal reinfarction. The timing of reperfusion therapy after symptom onset affects outcomes. Patients presenting >3 h after symptom onset are likely to benefit more from PCI than from thrombolysis. Nevertheless, PCI should be performed as soon as possible for optimal results. If PCI is to be delayed, then immediate thrombolysis is likely to be as effective as PCI. Registry data indicate that reperfusion for acute MI is currently underused, with different techniques frequently misapplied. Outcomes tend to be better at centers that perform a high volume of reperfusion procedures, partly due to shorter treatment delays. Facilitated PCI combines fibrinolytic therapy with angioplasty. It is designed to promote very early patency in those who respond to drug therapy, with very high final patency rates assured by angioplasty. Clinical trials have generally found facilitated PCI to be more efficacious than thrombolysis alone. Rescue PCI in cases of failed fibrinolysis is associated with a modest mortality benefit compared with conservative treatment. Myocardial injury following reperfusion after ischemia can limit the benefits of PCI and fibrinolysis; however, strategies for minimizing reperfusion injury have not yet shown clinical efficacy.

Continuous Administration of Nicorandil Decreases QT Dispersion During the Chronic Phase of Acute Myocardial Infarction

We previously reported that continuous intravenous (IV) administration of nicorandil (NIC) inhibits QT dispersion (QTd). However, no prior study has evaluated the efficacy of NIC when administered orally to acute myocardial infarction (AMI) patients following continuous IV administration. Thirty patients with anteroseptal infarction in whom revascularization was performed successfully within 6 hours of AMI onset were included in the study and assigned to one of 3 groups: group A (continuous IV administration of NIC), group B (continuous IV and oral administration of NIC), and group C (no treatment with NIC). After 24 hours, QTd in groups A and B was significantly decreased compared to QTd in group C (P < 0.01) (group A, 58.1; group B, 58.2; and group C, 81.3). The QTd obtained 3 months later was significantly shorter in group B subjects who were orally administered NIC, and QTd before percutaneous coronary intervention (PCI) was restored in group A, in which no NIC had been administered orally [group A, 66.7; group B, 54.1; and group C, 73.9; P < 0.05 (group A versus group B) and P < 0.01 (group B versus group C)]. The effects were evaluated by comparing different routes of administration. Continuous IV and subsequent oral administration of NIC inhibited prolongation of QTd, suggesting that these effects may prevent the occurrence of cardiac events during both the acute and chronic phases of AMI.

Myocardial protective effects of nicorandil during percutaneous coronary intervention in patients with unstable angina

BACKGROUND

The purpose of the study was to prospectively evaluate the protective effect of nicorandil during percutaneous coronary intervention (PCI) in patients with unstable angina (UAP).

METHODS AND RESULTS

Two hundred patients (61+/-10 year-old, male 143) diagnosed with UAP at an emergency medical center were randomly assigned to 2 groups: intravenous isosorbide dinitrate, Group I (n=100), or intravenous nicorandil, Group II (n=100). PCI was performed 12-48 h after infusion of each agent. Serum concentrations of creatine kinase-MB (CK-MB), cardiac troponin T (cTnT), and I (cTnI) were measured before and 6, 12, 24 h after PCI. Patients with non-coronary chest pain, requiring emergency coronary angiogram, temporary pacemaker or glycoprotein IIb/IIIa receptor blocker were excluded. PCI was successfully performed in 96 patients (Group I=54, 61.7+/-8.2 years, 32 males; Group II=42, 60.4+/-11.7 years, 27 males). No significant differences in clinical or coronary angiographic characteristics were observed between the 2 groups. The concentration of CK-MB was elevated in 9 patients (17%) of Group I and 6 (14%) of Group II, cTnT in 16 (30%), 6 (14%) and cTnI in 25 (46%), 9 (21%) after PCI. Elevation of any troponin was less frequent in Group II [28/54 (52%) vs 10/42 (24%) patients, p=0.01]. Major adverse coronary events during the 6-month clinical follow-up occurred in 9 (17%) of Group I and 5 patients of Group II (12%, p=NS). Follow-up echocardiography revealed lower left ventricular ejection fraction in Group I than in Group II (65.4+/-7.2% vs 71.0+/-6.7%, p=0.03).

CONCLUSION

Nicorandil has a myocardial protective effect during PCI in patients with UAP.

Evaluation of Transmural Myocardial Perfusion by Ultra-Harmonic Myocardial Contrast Echocardiography in Reperfused Acute Myocardial Infarction

BACKGROUND

The transmural distribution of myocardial perfusion is important for predicting the contractile reverse of an infarcted wall in reperfused acute myocardial infarction (AMI). Evaluating transmural myocardial perfusion by myocardial contrast echocardiography (MCE) could predict the long-term recovery of left ventricular (LV) function.

METHODS AND RESULTS

The study group comprised 20 consecutive patients with a first-episode anterior AMI with total occlusion of the proximal left anterior descending artery, who underwent successful percutaneous coronary intervention within 24 h of onset. MCE was performed on the 15th day after the onset, using ultraharmonic gray-scale imaging with intermittent end-systolic triggering every 4 beats or every 6 beats. Regions of interest were placed over both the endocardial and epicardial region at the mid-septal level. Regional wall motion (RWM) of the infarcted anterior wall and global LV function were assessed by 2-dimensional echocardiography and left ventriculography in both the acute and chronic phase. The transmural distribution of myocardial perfusion by MCE demonstrated a significant relation with RWM score index (r = 0.75, p = 0.0004). Recovery of RWM and LV ejection fraction (LVEF) at 6 months after reperfusion was significantly greater in the group with good perfusion of the epicardium according to MCE than in the poor perfusion group [RWM (SD/cord); -1.23+/-0.91 vs -3.51+/-0.84, p = 0.001, LVEF (%); 63.8+/-10.4 vs 47.0+/-3.4, p = 0.04].

CONCLUSIONS

Assessing the transmural distribution of myocardial perfusion by MCE can predict the long-term recovery of LV function after a reperfused AMI.

Nicorandil: a review of its use in the management of stable angina pectoris, including high-risk patients

Nicorandil (Adancor, Angicor, Dancor, Nikoril [Europe], Ikorel [Europe and Oceania], Sigmart [Japan, Korea and Taiwan]) is an adenosine triphosphate (ATP)-sensitive potassium (KATP) channel agonist with nitrate-like properties used in the management of stable angina pectoris. With well established monotherapeutic antianginal activity and a beneficial effect (when added to optimal antianginal therapy) on clinical outcomes in high-risk patients with stable angina, twice-daily oral nicorandil is a useful alternative or addition to other antianginal therapy.

Effects of nicorandil on cardiac sympathetic nerve activity after reperfusion therapy in patients with first anterior acute myocardial infarction

PURPOSE

Ischaemic preconditioning (PC) is a cardioprotective phenomenon in which short periods of myocardial ischaemia result in resistance to decreased contractile dysfunction during a subsequent period of sustained ischaemia. Nicorandil, an ATP-sensitive potassium channel opener, can induce PC effects on sympathetic nerves during myocardial ischaemia. However, its effects on cardiac sympathetic nerve activity (CSNA) and left ventricular remodelling have not been determined. In this study, we sought to determine whether nicorandil administration improves CSNA in patients with acute myocardial infarction (AMI).

METHODS

We studied 58 patients with first anterior AMI, who were randomly assigned to receive nicorandil (group A) or isosorbide dinitrate (group B) after primary coronary angioplasty. The nicorandil or isosorbide dinitrate was continuously infused for >48 h. The extent score (ES) was determined from 99mTc-pyrophosphate scintigraphy, and the total defect score (TDS) was determined from 201Tl scintigraphy 3-5 days after primary angioplasty. The left ventricular end-diastolic volume (LVEDV) and left ventricular ejection fraction (LVEF) were determined by left ventriculography 2 weeks later. The delayed heart/mediastinum count (H/M) ratio, delayed TDS and washout rate (WR) were determined from 123I-meta-iodobenzylguanidine (MIBG) images 3 weeks later. The left ventriculography results were re-examined 6 months after treatment.

RESULTS

Fifty patients originally enrolled in the trial completed the entire protocol. After treatment, no significant differences were observed in ES or left ventricular parameters between the two groups. However, in group A (n=25), the TDSs determined from 201Tl and 123I-MIBG were significantly lower (26+/-6 vs 30+/-5, P<0.01, and 32+/-8 vs 40+/-6, P<0.0001, respectively), the H/M ratio significantly higher (1.99+/-0.16 vs 1.77+/-0.30, P<0.005) and the WR significantly lower (36%+/-8% vs 44%+/-12%, P<0.005) than in group B (n=25). Moreover, 6 months after treatment, LVEDV and LVEF were better in group A than in group B.

CONCLUSION

These findings indicate that nicorandil can have beneficial effects on CSNA and left ventricular remodelling in patients with first anterior AMI.

Effects of a Distal Protection Device During Primary Stenting in Patients With Acute Anterior Myocardial Infarction

BACKGROUND

The angiographic no-reflow phenomenon is an adverse prognostic factor in patients with acute myocardial infarction (AMI). The aim of the present study was to evaluate the effects of an occlusive balloon type distal protection device (PercuSurge GuardWire: GW) during primary stenting in patients with anterior AMI.

METHODS AND RESULTS

The GW group included 42 patients treated by primary stenting with GW protection and the control group included 30 patients treated by primary stenting after thrombectomy without distal protection. Left ventricular (LV) function was measured and compared by left ventriculography obtained soon after percutaneous coronary intervention (PCI) and 3 weeks after onset. The corrected TIMI frame count values were lower in the GW group than in the control group (27.5+/-2.3 vs 35.1 +/-2.5, p=0.030). The number of patients with myocardial blush grade 3 after PCI was higher in the GW group than in the control group (45.7 vs 20.0%, p=0.029). Peak concentration of creatine kinase myocardial fraction was lower in the GW group than in the control group (326.6+/-41.5 vs 454.9+/-46.2 mg/dl, p=0.043). GW patients showed greater improvement at 3 weeks after PCI in terms of LV ejection fraction (+4.6+/-1.2 vs -1.1+/-1.5, p=0.004), LV end-systolic volume index (+0.5+/-2.4 vs +9.0+/-2.7, p=0.023), and regional wall motion abnormalities (-2.03+/-0.14 vs -2.51+/-0.14, p=0.018).

CONCLUSION

Primary stenting with GW protection can restore epicardial coronary flow and myocardial perfusion, and also preserve LV function in anterior AMI.

Multi-Detector Computed Tomography for Imaging of Subendocardial Infarction-Prediction of Wall Motion Recovery After Reperfused Anterior Myocardial Infarction-

BACKGROUND

After reperfusion therapy for acute myocardial infarction (AMI), evaluation of transmural myocardial microcirculation can indicate prognosis. The aim of the present study was to determine whether the evaluation of transmural myocardial microcirculation by newly developed 4-slice computed tomography (CT) can estimate the recovery of left ventricular function.

METHODS AND RESULTS

Seventeen consecutive patients who had anterior AMI with a total occlusion in the proximal left anterior descending artery (LAD) and who had undergone successful balloon reperfusion therapy within 24 h of the onset of AMI were examined. Four-slice CT was performed 10-14 days after AMI onset. The median of the epicardial perfusion ratio (infarcted anterior epicardial CT number/intact lateral epicardial CT number ratio = 92%) was used to categorize the cases into 2 groups: the transmural infarction group (n=8) and the subendocardial infarction group (n=9). Although no significant difference was observed between myocardial enhancement by CT in the acute phase and anterior wall motion or ejection fraction in the acute phase, the transmural infarction group showed poor recovery of anterior wall motion at 6 months after AMI onset, whereas the subendocardial infarction group exhibited good recovery of regional and global left ventricular function.

CONCLUSIONS

Transmural myocardial microcirculation imaged by 4-slice CT can predict wall motion recovery after AMI.