A controlled trial with a novel anti-ischemic agent, ranolazine, in chronic stable angina pectoris that is responsive to conventional antianginal agents. Ranolazine Study Group

Effects of ranolazine on various outcomes in patients with stable angina: an updated meta-analysis

OBJECTIVE

We determined the effect of ranolazine vs. placebo in angina patients on 1) selective measures of the ischemic burden, 2) cardiovascular outcomes, including atrial fibrillation incidence, 3) the in-treatment glycohemoglobin levels and the permanent discontinuations because of side effects, and 4) the achieved between-arms blood pressure and heart rate difference.

METHODS

PubMed and Cochrane Collaboration Library databases were searched for eligible trials until end of September 2020. Trial quality was assessed by the Rob2 tool. Risk ratios or achieved mean differences during follow-up and 95% confidence interval (CI) of categorical or continuous outcomes, respectively, were calculated (random-effects model). The relationship between discontinuation rates and ranolazine's mean dose was investigated by meta-regression analysis.

RESULTS

We selected 18 trials (n = 12,995 patients in patients with macro or microvascular coronary heart disease. Achieved blood pressure and heart rate at rest were not different between randomized arms. Ranolazine administration compared to placebo was associated with an increase of 1) total exercise duration by 30 seconds (95% CI, 18-42), 2) time to 1 mm ST-segment depression by 44 seconds (95% CI, 30-54), and 3) time to angina onset by 40 seconds (95% CI, 30-54). On average, the incidence of atrial fibrillation was reduced by 25% following ranolazine treatment compared to placebo, while glycohemoglobin showed a mean decrease of 0.4% (95% CI, 0.3-0.5%).

DISCUSSION

Ranolazine remains an effective anti-ischemic drug, increases the angina-free exercise duration, delays the onset of ST-segment depression. The beneficial effects of ranolazine are extended to atrial fibrillation reduction rates and better glycemic control.

Role of ranolazine in heart failure: From cellular to clinic perspective

Ranolazine was approved by the US Food and Drug Administration as an antianginal drug in 2006, and has been used since in certain groups of patients with stable angina. The therapeutic action of ranolazine was initially attributed to inhibitory effects on fatty acids metabolism. As investigations went on, however, it developed that the main beneficial effects of ranolazine arise from its action on the late sodium current in the heart. Since late sodium currents were discovered to be involved in various heart pathologies such as ischemia, arrhythmias, systolic and diastolic dysfunctions, and all these conditions are associated with heart failure, ranolazine has in some way been tested either directly or indirectly on heart failure in numerous experimental and clinical studies. As the heart continuously remodels following any sort of severe injury, the inhibition by ranolazine of the underlying mechanisms of cardiac remodeling including ion disturbances, oxidative stress, inflammation, apoptosis, fibrosis, metabolic dysregulation, and neurohormonal impairment are discussed, along with unresolved issues. A projection of pathologies targeted by ranolazine from cellular level to clinical is provided in this review.

Stereoselective quantitative analysis of ranolazine in plasma and tissue samples: application in pharmacokinetics and tissue distribution studies

This study aimed to develop a rapid and sensitive reversed-phase mode high-performance liquid chromatography-electrospray ionization coupled with a tandem mass spectrometry method for the simultaneous determination of ranolazine enantiomers in rat plasma and tissues.

Pharmacokinetics and Safety of Extended-release Ranolazine in Korean and White Healthy Subjects

PURPOSE

Ranolazine, an inhibitor of late inward sodium current, is an antianginal agent. In this study, the pharmacokinetic (PK) properties and tolerability of single- and multiple-dose ranolazine were compared between healthy Korean and white subjects.

METHODS

An open-label, ascending single- and multiple-dose study was conducted with healthy male Korean and white subjects. Subjects were administered 375-750 mg of ranolazine once in a single-dose and twice daily in multiple-dose based on their dose groups. Blood samples for the PK assessment were collected up to 48 h after dosing. The geometric mean ratio and its 90% confidence interval in Korean to white subjects for C_max, C_max,ss, AUC_last, and AUC_0-12h,ss of ranolazine were calculated. A population PK analysis was also performed. Safety profiles were assessed throughout the study.

FINDINGS

A total of 70 Korean and 48 white subjects completed the study. Ranolazine exposure was similar between Korean and white subjects in all dose groups; however, ranolazine exposure at 750 mg was observed to increase by up to 29% in Korean subjects compared with that in white subjects. On the basis of previous studies, these differences in ranolazine exposure between the 2 ethnic groups may not result in any clinically significant difference. Furthermore, ethnicity was not significantly correlated with the PK properties of ranolazine in the ranolazine PK model. In addition, no significant difference was found in the safety profile of ranolazine between the 2 ethnic groups.

IMPLICATIONS

The PK properties of ranolazine had no clinically significant difference, and no difference was found in the safety profiles of ranolazine between Korean and white subjects. It is anticipated that ranolazine can be administered in Korean subjects without dose adjustment. ClinicalTrials.gov identifier: NCT02817932.

Drug-induced QT prolongation: Concordance of preclinical anesthetized canine model in relation to published clinical observations for ten CiPA drugs

INTRODUCTION

The Comprehensive In Vitro Proarrhythmia Assay (CiPA) initiative differentiates torsadogenic risk of 28 drugs affecting ventricular repolarization based on multiple in vitro human derived ionic currents. However, a standardized prospective assessment of the electrophysiologic effects of these drugs in an integrated in vivo preclinical cardiovascular model is lacking. This study questioned whether QTc interval prolongation in a preclinical in vivo model could detect clinically reported QTc prolongation and assign torsadogenic risk for ten CiPA drugs.

METHODS

An acute intravenous administered ascending dose anesthetized dog cardiovascular model was used to assess QTc prolongation along with other electrocardiographic (PR, QRS intervals) and hemodynamic (heart rate, blood pressures, left ventricular contractility) parameters at plasma concentrations spanning and exceeding clinical exposures. hERG current block potency was characterized using IC₅₀ values from automated patch clamp.

RESULTS

All eight drugs eliciting clinical QTc prolongation also delayed repolarization in anesthetized dogs at plasma concentrations within four-fold clinical exposures. In vitro QTc safety margins (defined based on clinical C_max values/plasma concentrations eliciting statistically significant QTc prolongation in dogs) were lower for high vs intermediate torsadogenic risk drugs. In comparison, hERG IC₁₀ values represented as total drug concentrations were better predictors of preclinical QTc prolongation than hERG IC₅₀ values.

CONCLUSION

There was good concordance for QTc prolongation in the anesthetized dog model and clinical torsadogenic risk assignment. QTc assessment in the anesthetized dog remains a valuable part of a more comprehensive preclinical integrated risk assessment for delayed repolarization and torsadogenic risk as part of a global cardiovascular evaluation.

Ranolazine Induced Bradycardia, Renal Failure, and Hyperkalemia: A BRASH Syndrome Variant

Ranolazine is a well-known antianginal drug, that was first licensed for use in the United States in 2006. It was objectively shown to improve exercise capacity and to lengthen the time to symptom onset in patients with coronary artery disease. The most commonly reported side effects of ranolazine include dizziness, headache, constipation, and nausea. Here, we describe a case of bradycardia, hyperkalemia, and acute renal injury in the setting of ranolazine use. Our patient is an 88-year-old female who presented with abdominal pain, nausea, and vomiting. Her medical comorbidities included hypertension, diabetes, CAD, heart failure with preserved ejection fraction, paroxysmal atrial fibrillation, hypothyroidism, and a history of cerebrovascular accident without any residual deficits. Her prescription regimen included amlodipine, furosemide, isosorbide mononitrate, levothyroxine, metformin, omeprazole, and ranolazine. Physical examination was remarkable for bradycardia and decreased breath sounds in the left lower lung field. Laboratory studies were significant for a serum potassium level of 6.8 mEq/L and a serum creatinine level of 1.6 mg/dL. She was given insulin with dextrose, sodium polystyrene, and calcium gluconate in addition to fluids. Her bradycardia and renal function worsened over the next 24 hours. Ranolazine was discontinued. Metabolic derangements were treated appropriately. After 48 hours from presentation, potassium and renal function returned to baseline and her heart rate improved to a range of 60-100 bpm. She was discharged with an outpatient cardiology follow-up. Ranolazine treatment was not continued upon discharge. In summary, our case illustrates an association between ranolazine and renal failure induced hyperkalemia, leading to conduction delays in the myocardium. Though further studies are warranted, we suspect that this is a variant of the recently described BRASH syndrome. We propose that in cases such as ours, along with treatment of the hyperkalemia, medication review and removal of any offending agent should be considered.

Ranolazine Reduces Angina in Women with Ischemic Heart Disease: Results of an Open-Label, Multicenter Trial

Background: Persistent angina is prevalent in women, who more often present with atypical angina, and experience less relief from antianginal therapies. The impact of ranolazine on female-specific angina is unclear. A single-arm, open-label trial was conducted to quantify the impact of ranolazine on angina in women with ischemic heart disease (IHD). Materials and Methods: Women with IHD and ≥2 angina episodes/week were recruited from 30 U.S. sites. Angina and nitroglycerin (NTG) consumption were assessed using patient-reported diaries, Seattle Angina Questionnaire (SAQ), Duke Activity Score Index (DASI), and Women's Ischemia Symptom Questionnaire (WISQ) at baseline and at 4 weeks of treatment with ranolazine 500 mg twice/day. A modified intent-to-treat analysis and parametric or nonparametric methods were used as appropriate to analyze changes. Results: Of 171 women enrolled, mean age was 65 ± 12 years. Of the 159 women included in the analysis, at week 4 compared to baseline, median angina frequency decreased with ranolazine treatment from 5.0 to 1.5 attacks/week and median change from baseline was -3.3 (95% confidence interval [CI]: -4.0 to -2.5; p ≤ 0.0001). Median NTG consumption decreased from 2.0 to 0.0 per week over the 4 weeks and median change was -1.0 (95% CI: -2.0 to -0.5; p < 0.0001). All five SAQ subscales showed mean improvements: physical limitation 9.2 (standard error [SE] 1.5; p < 0.0001), angina stability 31.8 (SE 2.7; p < 0.0001), angina frequency 17.7 (SE 1.6; p < 0.0001), treatment satisfaction 9.3 (SE 1.6; p < 0.0001), and disease perception 2.9 (SE 0.8; p < 0.0001). DASI score also improved 2.9 (SE 0.8; p = 0.0014). WISQ subscales also showed significant improvements (all p < 0.0001). Thirty-one women reported drug-related adverse events (AEs), predominantly mild to moderate gastrointestinal symptoms. Conclusions: Women with IHD treated with ranolazine for 4 weeks experienced less angina measured by SAQ and WISQ. NTG use decreased, physical activity improved, and treatment satisfaction improved. AEs were consistent with prior reports.

Single dose oral ranolazine pharmacokinetics in patients receiving maintenance hemodialysis

Purpose: Ranolazine is a novel anti-angina treatment approved in the United States for chronic stable angina. Ranolazine pharmacokinetics have not been studied previously in patients who receive maintenance hemodialysis. This study describes the pharmacokinetics of ranolazine and three major metabolites (CVT-2738, CVT-2512, CVT-2514) in patients receiving thrice weekly hemodialysis.

Methods: Eight participants receiving maintenance hemodialysis completed this prospective, open-label study (study identifier NCT01435174 at Clinicaltrials.gov). Three participants received a single tablet of ranolazine 500 mg (followed by an interim analysis), and five received 2 tablets of ranolazine 500 mg. Blood samples were collected over 65 h to determine the pharmacokinetic characteristics during and between hemodialysis sessions. Non-compartmental analysis was used to determine the individual pharmacokinetic parameters.

Results: Ranolazine off-hemodialysis elimination phase half-lives were 3.6 and 3.9 h for 500 mg and 1000 mg doses, respectively. The time to maximum concentration ranged from 2 to 18 hours and the average maximum concentration was 0.65 ± 0.27 mcg/mL and 1.18 ± 0.48 mcg/mL for ranolazine 500 mg and 1000 mg dose, respectively. The mean hemodialysis percent reduction ratio for the ranolazine 500 mg dose was 52.3 ± 8.1% and for the ranolazine 1000 mg dose was 69.2 ± 37.6%.

Conclusions: Data on ranolazine dosing in patients receiving maintenance hemodialysis is almost non-existent. Given the extent of pharmacokinetic variability observed with the 500 mg and 1000 mg oral doses of ranolazine, neither can be recommended as a starting dose in patients receiving maintenance hemodialysis. Guided by the information gained form this study about the extent of hemodialytic drug clearance, further multi-dose clinical trials of ranolazine are needed to optimize therapeutic outcomes in this patient population.

Management of stable angina pectoris in private healthcare settings in South Africa

Aim

Angina pectoris continues to affect multitudes of people around the world. In this study the management of stable angina pectoris in private healthcare settings in South Africa (SA) was investigated. In particular, we reviewed the frequency of medical versus surgical interventions when used as first-line therapy.

Methods

This was a retrospective inferential study carried out using records of patients in private healthcare settings. All cases that were authorised for reimbursement by medical aid schemes for revascularisation between 2009 and 2014 were retrieved and a database was created. Data were analysed using MicrosoftR Excel and GraphPad PrismR version 5. The differences (where applicable) were considered statistically significant if the p-value was ≤ 0.05.

Results

Nine hundred and twenty-two patients, consisting of 585 males (average age 64.7 years; SD 12.9) and 337 females (average age 65.5 years; SD 14.3), met the inclusion criteria. One hundred and seventy-eighty or 54%, 156 (43%) and 86 (63%) patients with hypertension, hyperlipidaemia and diabetes, respectively, were treated with surgery only. For these patients, percutaneous coronary interventions (PCIs) were significantly (p < 0.0001) preferred first-line interventions over optimal medical therapy (OMT). Four hundred and thirty-six or 47% of all patients studied were managed with surgery only, while only 25% (227) were managed with OMT. It took 60 months (five years) for patients who were treated with OMT before their first surgical intervention(s) to require the second revascularisation. About 71% of patients who received medical therapy were placed on only one drug, the so called sub-optimal medical therapy (SOMT).

Conclusion

The management of stable angina pectoris in private healthcare settings in SA is skewed towards surgical interventions as opposed to OMT. This is contrary to what consistent scientific evidence and international treatment guidelines suggest.

Daily Activity Measured With Wearable Technology as a Novel Measurement of Treatment Effect in Patients With Coronary Microvascular Dysfunction: Substudy of a Randomized Controlled Crossover Trial

BACKGROUND

Digital wearable devices provide a "real-world" assessment of physical activity and quantify intervention-related changes in clinical trials. However, the value of digital wearable device-recorded physical activity as a clinical trial outcome is unknown.

OBJECTIVE

Because late sodium channel inhibition (ranolazine) improves stress laboratory exercise duration among angina patients, we proposed that this benefit could be quantified and translated during daily life by measuring digital wearable device-determined step count in a clinical trial.

METHODS

We conducted a substudy in a randomized, double-blinded, placebo-controlled, crossover trial of participants with angina and coronary microvascular dysfunction (CMD) with no obstructive coronary artery disease to evaluate the value of digital wearable device monitoring. Ranolazine or placebo were administered (500-1000 mg twice a day) for 2 weeks with a subsequent 2-week washout followed by crossover to ranolazine or placebo (500-1000 mg twice a day) for an additional 2 weeks. The outcome of interest was within-subject difference in Fitbit Flex daily step count during week 2 of ranolazine versus placebo during each treatment period. Secondary outcomes included within-subject differences in angina, quality of life, myocardial perfusion reserve, and diastolic function.

RESULTS

A total of 43 participants were enrolled in the substudy and 30 successfully completed the substudy for analysis. Overall, late sodium channel inhibition reduced within-subject daily step count versus placebo (mean 5757 [SD 3076] vs mean 6593 [SD 339], P=.01) but did not improve angina (Seattle Angina Questionnaire-7 [SAQ-7]) (P=.83). Among the subgroup with improved angina (SAQ-7), a direct correlation with increased step count (r=.42, P=.02) was observed.

CONCLUSIONS

We report one of the first studies to use digital wearable device-determined step count as an outcome variable in a placebo-controlled crossover trial of late sodium channel inhibition in participants with CMD. Our substudy demonstrates that late sodium channel inhibition was associated with a decreased step count overall, although the subgroup with angina improvement had a step count increase. Our findings suggest digital wearable device technology may provide new insights in clinical trial research.

TRIAL REGISTRATION

Clinicaltrials.gov NCT01342029; https://clinicaltrials.gov/ct2/show/NCT01342029 (Archived by WebCite at http://www.webcitation.org/6uyd6B2PO).

Ranolazine for stable angina pectoris

BACKGROUND

Stable angina pectoris is a chronic medical condition with significant impact on mortality and quality of life; it can be macrovascular or microvascular in origin. Ranolazine is a second-line anti-anginal drug approved for use in people with stable angina. However, the effects of ranolazine for people with angina are considered to be modest, with uncertain clinical relevance.

OBJECTIVES

To assess the effects of ranolazine on cardiovascular and non-cardiovascular mortality, all-cause mortality, quality of life, acute myocardial infarction incidence, angina episodes frequency and adverse events incidence in stable angina patients, used either as monotherapy or as add-on therapy, and compared to placebo or any other anti-anginal agent.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase and the Conference Proceedings Citation Index - Science in February 2016, as well as regional databases and trials registers. We also screened reference lists.

SELECTION CRITERIA

Randomised controlled trials (RCTs) which directly compared the effects of ranolazine versus placebo or other anti-anginals in people with stable angina pectoris were eligible for inclusion.

DATA COLLECTION AND ANALYSIS

Two authors independently selected studies, extracted data and assessed risk of bias. Estimates of treatment effects were calculated using risk ratios (RR), mean differences (MD) and standardised mean differences (SMD) with 95% confidence intervals (CI) using a fixed-effect model. Where we found statistically significant heterogeneity (Chi² P < 0.10), we used a random-effects model for pooling estimates. Meta-analysis was not performed where we found considerable heterogeneity (I² ≥ 75%). We used GRADE criteria to assess evidence quality and the GRADE profiler (GRADEpro GDT) to import data from Review Manager 5.3 to create 'Summary of findings' tables.

MAIN RESULTS

We included 17 RCTs (9975 participants, mean age 63.3 years). We found very limited (or no) data to inform most planned comparisons. Summary data were used to inform comparison of ranolazine versus placebo. Overall, risk of bias was assessed as unclear.For add-on ranolazine compared to placebo, no data were available to estimate cardiovascular and non-cardiovascular mortality. We found uncertainty about the effect of ranolazine on: all-cause mortality (1000 mg twice daily, RR 0.83, 95% CI 0.26 to 2.71; 3 studies, 2053 participants; low quality evidence); quality of life (any dose, SMD 0.25, 95% CI -0.01 to 0.52; 4 studies, 1563 participants; I² = 73%; moderate quality evidence); and incidence of non-fatal acute myocardial infarction (AMI) (1000mg twice daily, RR 0.40, 95% CI 0.08 to 2.07; 2 studies, 1509 participants; low quality evidence). Add-on ranolazine 1000 mg twice daily reduced the fervour of angina episodes (MD -0.66, 95% CI -0.97 to -0.35; 3 studies, 2004 participants; I² = 39%; moderate quality evidence) but increased the risk of non-serious adverse events (RR 1.22, 95% CI 1.06 to 1.40; 3 studies, 2053 participants; moderate quality evidence).For ranolazine as monotherapy compared to placebo, we found uncertain effect on cardiovascular mortality (1000 mg twice daily, RR 1.03, 95% CI 0.56 to 1.88; 1 study, 2604 participants; low quality evidence). No data were available to estimate non-cardiovascular mortality. We also found an uncertain effect on all-cause mortality for ranolazine (1000 mg twice daily, RR 1.00, 95% CI 0.81 to 1.25; 3 studies, 6249 participants; low quality evidence), quality of life (1000 mg twice daily, MD 0.28, 95% CI -1.57 to 2.13; 3 studies, 2254 participants; moderate quality evidence), non-fatal AMI incidence (any dose, RR 0.88, 95% CI 0.69 to 1.12; 3 studies, 2983 participants; I² = 50%; low quality evidence), and frequency of angina episodes (any dose, MD 0.08, 95% CI -0.85 to 1.01; 2 studies, 402 participants; low quality evidence). We found an increased risk for non-serious adverse events associated with ranolazine (any dose, RR 1.50, 95% CI 1.12 to 2.00; 3 studies, 947 participants; very low quality evidence).

AUTHORS' CONCLUSIONS

We found very low quality evidence showing that people with stable angina who received ranolazine as monotherapy had increased risk of presenting non-serious adverse events compared to those given placebo. We found low quality evidence indicating that people with stable angina who received ranolazine showed uncertain effect on the risk of cardiovascular death (for ranolazine given as monotherapy), all-cause death and non-fatal AMI, and the frequency of angina episodes (for ranolazine given as monotherapy) compared to those given placebo. Moderate quality evidence indicated that people with stable angina who received ranolazine showed uncertain effect on quality of life compared with people who received placebo. Moderate quality evidence also indicated that people with stable angina who received ranolazine as add-on therapy had fewer angina episodes but increased risk of presenting non-serious adverse events compared to those given placebo.

Antiarrhythmic and Proarrhythmic Properties of QT-Prolonging Antianginal Drugs

In recent years there has been a major reorientation of drug therapy for cardiac arrhythmias, its changing role, and above all, a radical change in the class of arrhythmia drugs because of their impact on mortality. The decline in the use of sodium-channel blockers has led to an expanding use of β-blockers and simple or complex class III agents for controlling cardiac arrhythmias. Success with these agents in the context of their side effects has spurred the development of compounds with simpler ion-channel blocking properties that have less complex adverse reactions. The resulting so-called pure class III agents, such as dofetilide or ibutilide, were found to have antifibrillatory effects in atrial fibrillation and flutter and in ventricular tachyarrhythmias. Such agents are effective and have diversity, but they have come into therapeutics with a price: the sometimes-fatal torsades de pointes. The drug amiodarone, a complex compound that was synthesized as an antianginal agent, has been an exception in this regard. Its therapeutic use is associated with a negligibly low incidence of torsades de pointes, even though the drug produces significant bradycardia and QT lengthening to 500 to 700 msec. Recent electrophysiologic studies suggest that this paradox is likely due to the differential block of ion channels in endocardium, epicardium, midmyocardial (M) cells, and Purkinje fibers in the ventricular myocardium. There is also clinical evidence suggesting that amiodarone reduces the “torsadogenic” effects of pure class III agents. Ranolazine was also synthesized for the development of antianginal properties that stem from a partial inhibition of fatty acid oxidation; it too has been found to have electrophysioloigic properties. These are somewhat similar to those of amiodarone on ion channels in endocardium, epicardium, M cells, and Purkinje fibers in the ventricular myocardium, but the drug does not prolong the QT interval to the same extent as amiodarone does. Thus, the drug produces modest increases in repolarization as judged by its effects on the action potential duration (APD) without the potential for the development of torsades de pointes. By virtue of its suppressant action on early afterdepolarizations and triggered activity in Purkinje fibers and M cells, the drug appears to have a powerful potential for reducing the torsadogenic proclivity of conventional class III antiarrhythmic compounds. The rationale for the therapeutic niche for amiodarone, and especially in the case of ranolazine, in the prevention of drug-induced torsades de pointes is discussed.

Efficacy and Safety of a Metabolic Modulator Drug in Chronic Stable Angina: Review of Evidence from Clinical Trials

A number of newer antianginal agents, including nicorandil, trimetazidine, and ivabradine, have been synthesized in recent years, but ranolazine, a piperazine derivative that partially inhibits fatty acid oxidation and the late INa current in animal models, is of particular interest mechanistically. Earlier clinical trials with immediate-release ranolazine led to the current sustained-release version tested in the Monotherapy Assessment of Ranolazine In Stable Angina (MARISA) (n = 193) and Combination Assessment of Ranolazine In Stable Angina (CARISA) trials (n = 823) of patients with chronic angina and severe limitation of exercise capacity (ie, < 5 metabolic equivalents). MARISA was a placebo-controlled, randomized trial that compared ranolazine monotherapy (500 mg, 1000 mg, and 1500 mg, twice daily) to placebo. CARISA was a placebo-controlled trial that randomized patients on background 1-blocker or calcium antagonist therapy to placebo or ranolazine (750 mg or 1000 mg, twice daily). Both studies showed a significant increase in total exercise duration, time to angina onset, and time to 1 mm ST segment depression. The average magnitude of increase in exercise duration over placebo was 29 to 56 seconds at peak and 24 to 46 seconds at trough with the 3 doses tested in MARISA, and 24 to 34 seconds greater than placebo with the 2 doses used in CARISA. The beneficial effect was achieved without clinically important changes in rest or exercise heart rate or blood pressure. Weekly angina attack frequency and nitroglycerin usage were significantly reduced in a dose-dependent manner in the 12-week CARISA trial. Reported adverse effects were similar in MARISA and CARISA and consisted of asthenia, nausea, constipation, and dizziness. Syncope, reported in 8 patients at doses of 1000 mg twice daily or more may be related to attenuation of α-1 receptor activity. The mean QTc interval increased with dose and was less than 10 msec on ranolazine at 1000 mg twice daily. The mortality rates at 1 and 2 years in MARISA and CARISA open-label run-on studies were 2% and less than 5%, acceptable for this high-risk population with limited exercise capacity. In conclusion, clinical trial evidence with ranolazine to date is consistent with its proposed mechanism of action and demonstrates an effective antianginal profile that may benefit patients with severe chronic angina.

Ranolazine, an Inhibitor of the Late Sodium Channel Current, Reduces Postischemic Myocardial Dysfunction in the Rabbit

Ranolazine is a selective inhibitor of the late sodium current relative to peak sodium channel current, and via this mechanism, it may decrease sodium-dependent intracellular calcium overload during ischemia and reperfusion. Ranolazine reduces the frequency of angina attacks, but there is little information on its effects on myocardial stunning after short-term ischemia. The objective of this study was to test the effects of ranolazine on left ventricular (LV) function and myocardial stunning after ischemia/reperfusion in rabbits. Myocardial stunning was induced in rabbits by 15 minutes of coronary artery occlusion (CAO) followed by 3 hours reperfusion. Ten minutes before CAO, rabbits were randomly assigned to vehicle (n = 15) or ranolazine (2 mg/kg bolus plus 60 μg/kg/min infusion, IV, n = 15). Myocardial stunning was assessed by LV 2-dimensional echocardiography using, as a marker of severity, ischemic free-wall fractional thickening (FWft; systolic wall thickness – diastolic wall thickness/diastolic wall thickness). Regional ejection fraction (EF) was also assessed. During CAO, FWft was depressed in both groups, indicating an ischemic insult (FWft was reduced from 0.62 ± 0.05 at baseline to 0.10 ± 0.04 in vehicle and from 0.73 ± 0.05 to 0.26 ± 0.07 in ranolazine, P < 0.05, ranolazine vs vehicle). After reperfusion, previously ischemic myocardium remained stunned; however, FWft recovered significantly better in ranolazine (0.51 ± 0.05) than in vehicle (0.35 ± 0.04, P = .027). Baseline EF was 0.65 ± 0.02 in the ranolazine and 0.68 ± 0.02 in vehicle ( P = ns). During CAO, EF was reduced by 36% ± 6% in vehicle versus only 20% ± 6% in ranolazine ( P < .05). At the end of reperfusion, EF remained depressed in both groups, but the reduction in the vehicle group (25% ± 5%) was significantly worse than in ranolazine (9% ± 4%, P = .017). Improvement in function was independent of necrosis (negligible) or differences in hemodynamics (no differences between groups). Ranolazine treatment reduced myocardial stunning following brief ischemia/reperfusion suggesting that inhibiting the late sodium channel current may be a novel approach to treating stunning independent of effects on hemodynamics.

Ranolazine: Electrophysiologic Effect, Efficacy, and Safety in Patients with Cardiac Arrhythmias

Ranolazine is currently approved as an antianginal agent in patients with chronic angina (class IIA). Ranolazine exhibits antiarrhythmic effects that are related to its multichannel blocking effect, predominantly inhibition of late sodium (late INa) current and the rapid potassium rectifier current (IKr), as well as ICa, late ICa, and INa-Ca. It also suppresses the early and delayed after depolarizations. Ranolazine is effective in the suppression of atrial and ventricular arrhythmias (off-label use) without significant proarrhythmic effect. Currently, ongoing trials are evaluating the efficacy and safety of ranolazine in patients with cardiac arrhythmias; preliminary results suggest that ranolazine, when used alone or in combination with dronedarone, is safe and effective in reducing atrial fibrillation. Ranolazine is not currently approved by the US Food and Drug Administration as an antiarrhythmic agent.

Ranolazine and Ivabradine: two different modalities to act against ischemic heart disease

Among the innovative drugs recently introduced for the management of chronic stable angina, Ranolazine and ivabradine represent two most true innovations. In fact, even if both drugs act by reducing myocardial work and thus oxygen consumption, this happens by a peculiar mechanism unlike that of conventional antischemic drugs. Ranolazine mediates its antianginal effects by the inhibition of cardiac late sodium current. This improves myocardial relaxation favoring myocardial perfusion. Ivabradine is a selective If channel blocker and acts by reducing firing rate of pacemaker cells in the sinoatrial node, without affecting the duration of action potential. The reduction of heart rate causes a reduction of left ventricular end diastolic pressure and increases the time useful to coronary flow by a prolongation of the diastole. A body of evidence found that two drugs are useful in ischemic patients whether at rest or during exercise. In addition, they can be used in monotherapy or in association with other conventional anti-ischemic drugs. The two medications could be used with advantage also in microvascular angina when standard therapy is ineffective. Thus, the two drugs represent an adjunctive and powerful therapeutic modality for the treatment of chronic stable angina, especially when conventional antianginal drugs were insufficient or inadequate.

Antagonism of Nav channels and α1-adrenergic receptors contributes to vascular smooth muscle effects of ranolazine

Ranolazine is a recently developed drug used for the treatment of patients with chronic stable angina. It is a selective inhibitor of the persistent cardiac Na⁺ current (I_Na), and is known to reduce the Na⁺-dependent Ca²⁺ overload that occurs in cardiomyocytes during ischemia. Vascular effects of ranolazine, such as vasorelaxation,have been reported and may involve multiple pathways. As voltage-gated Na⁺ channels (Na_v) present in arteries play a role in contraction, we hypothesized that ranolazine could target these channels. We studied the effects of ranolazine in vitro on cultured aortic smooth muscle cells (SMC) and ex vivo on rat aortas in conditions known to specifically activate or promote I_Na. We observed that in the presence of the Na_v channel agonist veratridine, ranolazine inhibited I_Na and intracellular Ca²⁺ calcium increase in SMC, and arterial vasoconstriction. In arterial SMC, ranolazine inhibited the activity of tetrodotoxin-sensitive voltage-gated Na_v channels and thus antagonized contraction promoted by low KCl depolarization. Furthermore, the vasorelaxant effects of ranolazine, also observed in human arteries and independent of the endothelium, involved antagonization of the α₁-adrenergic receptor. Combined α₁-adrenergic antagonization and inhibition of SMCs Na_v channels could be involved in the vascular effects of ranolazine.

Effects of the antianginal drug, ranolazine, on the brain sodium channel Na(V)1.2 and its modulation by extracellular protons

BACKGROUND AND PURPOSE

Ranolazine is an antianginal drug currently approved for treatment of angina pectoris in the United States. Recent studies have focused on its effects on neuronal channels and its possible therapeutic uses in the nervous system. We characterized how ranolazine affects the brain sodium channel, Na(V)1.2, and how its actions are modulated by low pH. In this way, we further explore ranolazine's potential as an anticonvulsant and its efficacy in conditions like those during an ischaemic stroke.

EXPERIMENTAL APPROACH

We performed whole-cell patch-clamp experiments on the voltage-gated sodium channel, Na(V)1.2. Experiments were performed with extracellular solution titrated to either pH 7.4 or pH 6.0 before and after ranolazine perfusion.

KEY RESULTS

Ranolazine accelerates onset and slows recovery of fast and slow inactivation. Ranolazine increases the maximum probability of use-dependent inactivation and reduces macroscopic and ramp sodium currents at pH 7.4. pH 6.0 reduced the slowing of fast inactivation recovery and inhibited use-dependent block by ranolazine. In the presence of ranolazine, the time constants of slow inactivation recovery and onset were significantly increased at pH 6.0 relative to pH 7.4 with 100 μM ranolazine.

CONCLUSIONS AND IMPLICATIONS

Our work provides novel insights into the modulation of brain sodium channel, Na(V)1.2, by ranolazine. We demonstrate that ranolazine binds Na(V)1.2 in a state-dependent manner, and that the effects of ranolazine are slowed but not abolished by protons. Our results suggest that further research performed on channels with epilepsy-causing mutations may prove ranolazine to be an efficacious therapy.

Update on ranolazine in the management of angina

Mortality rates attributable to coronary heart disease have declined in recent years, possibly related to changes in clinical presentation patterns and use of proven secondary prevention strategies. Chronic stable angina (CSA) remains prevalent, and the goal of treatment is control of symptoms and reduction in cardiovascular events. Ranolazine is a selective inhibitor of the late sodium current in myocytes with anti-ischemic and metabolic properties. It was approved by the US Food and Drug Administration in 2006 for use in patients with CSA. Multiple, randomized, placebo-controlled trials have shown that ranolazine improves functional capacity and decreases anginal episodes in CSA patients, despite a lack of a significant hemodynamic effect. Ranolazine did not improve cardiovascular mortality or affect incidence of myocardial infarction in the MERLIN (Metabolic Efficiency with Ranolazine for Less Ischemia in Non-ST-Elevation Acute Coronary Syndrome)-TIMI (Thrombolysis In Myocardial Infarction) 36 trial, but significantly decreased the incidence of recurrent angina. More recently, ranolazine has been shown to have beneficial and potent antiarrhythmic effects, both on supraventricular and ventricular tachyarrhythmias, largely due to its inhibition of the late sodium current. Randomized controlled trials testing these effects are underway. Lastly, ranolazine appears to be cost-effective due to its ability to decrease angina-related hospitalizations and improve quality of life.

The usefulness of ranolazine for the treatment of refractory chronic stable angina pectoris as determined from a systematic review of randomized controlled trials

Despite the use of traditional antianginal medications (i.e., β blockers, calcium channel blockers, and nitrates) and revascularization therapies, symptoms of chronic stable angina pectoris (CSAP) persist in ≥25% of patients. The objective of this systematic review was to synthesize the available evidence from randomized controlled trials (RCTs) of ranolazine for the treatment of CSAP. We systematically searched the Cochrane Register of Controlled Trials, EMBASE, and MEDLINE through July 2013 for RCTs comparing ranolazine with placebo or antianginal medications administered as part of usual care for the management of CSAP. End points of interest included exercise stress test performance (duration, time to angina, and time to ST-segment depression), frequency of angina attacks/week, nitroglycerin use/week, and quality of life. We identified 7 RCTs (n = 3,317) of patients with CSAP due to coronary artery disease. Comparators included placebo, amlodipine, and atenolol. All but 1 trial showed a statistically significant improvement in all 3 exercise stress test parameters with ranolazine compared with placebo. Ranolazine also reduced angina frequency and nitroglycerin use compared with placebo. These findings were consistent whether or not patients were also prescribed traditional antianginal pharmacotherapy. In conclusion, ranolazine reduces anginal symptoms among patients with symptomatic CSAP despite their use of traditional antianginal medications.

Ranolazine: new approach for the treatment of stable angina pectoris

Myocardial ischemia is a metabolic problem involving reduced delivery of oxygen to cardiac mitochondria, resulting in less ATP formation, acceleration of glycolysis and production of lactate and H+ by the cell. Traditional therapies for ischemia aim at restoring the balance between mitochondrial ATP production and breakdown by reducing the need for ATP via suppression of heart rate, blood pressure and cardiac contractility, or by increasing oxygen delivery via increased myocardial blood flow. Despite optimal treatment with traditional hemodynamically oriented drugs (beta-adrenergic receptor antagonist, Ca2+ channel antagonist and nitrates), many patients continue to suffer from angina. Thus, there is a need for anti-anginal drugs that act directly on cardiomyocytes to lessen the metabolic abnormalities induced by ischemia and reduce the symptoms (chest pain and exercise intolerance). Ranolazine has been demonstrated to improve exercise time to angina or 1 mm of ST-segment depression in a manner similar to currently approved drugs, but without any significant effects on heart rate or blood pressure at rest or during exercise. In two Phase III trials, ranolazine improved exercise tolerance and reduced the frequency of angina attacks in chronic severe angina patients when administered either as monotherapy or on a background of atenolol, amlodinine or diltiazem. At present, ranolazine is under review for US Food and Drug Administration approval and, if approved, it will represent the first drug of its class in the USA.

Anti-anginal and anti-ischemic effects of late sodium current inhibition

The effective treatment of coronary artery disease targets two distinct goals, controlling symptomatic angina and decreasing the adverse events associated with ischemia. Traditional anti-anginal and anti-ischemic drugs function by altering the determinants of myocardial oxygen supply or demand, usually by altering loading conditions, changing the heart rate, or impacting contractility. Blockade of the late inward sodium current, late I(Na), offers another target for the treatment of ischemia. Blockade of late I(Na) reduces the sodium and calcium overload that follows ischemia. This improves myocardial relaxation and reduces left ventricular diastolic stiffness, in turn enhancing myocardial contractility and perfusion. Ranolazine, a late I(Na) inhibitor, has been shown to provide both anti-anginal and anti-ischemic benefits without significant alterations in the heart rate and blood pressure in patients with stable coronary artery disease. When evaluated in patients with acute coronary syndrome, ranolazine has been shown to decrease recurrent ischemia, but not significantly reduce the risk of death or myocardial infarction. This review will address the rationale that inhibition of the late sodium current is beneficial in reducing cardiac dysfunction during ischemia, and discuss the clinical studies supporting the use of ranolazine for its anti-anginal and anti-ischemic effects.

Ranolazine: clinical applications and therapeutic basis

Ranolazine is currently approved for use in chronic angina. The basis for this use is likely related to inhibition of late sodium channels with resultant beneficial downstream effects. Randomized clinical trials have demonstrated an improvement in exercise capacity and reduction in angina episodes with ranolazine. This therapeutic benefit occurs without the hemodynamic effects seen with the conventional antianginal agents. The inhibition of late sodium channels as well as other ion currents has a central role in the potential use of ranolazine in ischemic heart disease, arrhythmias, and heart failure. Despite its QTc-prolonging action, albeit minimal, clinical data have not shown a predisposition to torsades de pointes, and the medication has shown a reasonable safety profile even in those with structural heart disease. In this article we present the experimental and clinical data that support its current therapeutic role, and provide insight into potential future clinical applications.

Safety and Efficacy of Ranolazine for the Treatment of Chronic Angina Pectoris

Coronary heart disease is a global malady and it is the leading cause of death in the United States. Chronic stable angina is the most common manifestation of coronary heart disease and it results from the imbalance between myocardial oxygen supply and demand due to reduction in coronary blood flow. Therefore, in addition to lifestyle changes, commonly used pharmaceutical treatments for angina (nitrates, β-blockers, Ca2+ channel blockers) are aimed at increasing blood flow or decreasing O2 demand. However, patients may continue to experience symptoms of angina. Ranolazine is a relatively new drug with anti-anginal and anti-arrhythmic effects. Its anti-anginal mechanism is not clearly understood but the general consensus is that ranolazine brings about its anti-anginal effects by inhibiting the late Na+ current and the subsequent intracellular Ca2+ accumulation. Recent studies suggest other effects of ranolazine that may explain its anti-anginal and anti-arrhythmic effects. Nonetheless, clinical trials have proven the efficacy of ranolazine in treating chronic angina. It has been shown to be ineffective, however, in treating acute coronary syndrome patients. Ranolazine is a safe drug with minimal side effects. It is metabolized mainly in the liver and cleared by the kidney. Therefore, caution must be taken in patients with impaired hepatic or renal function. Due to its efficacy and safety, ranolazine was approved for the treatment of chronic angina by the Food and Drug Administration (FDA) in 2006.

Effect of ranolazine on rat intrarenal arteries in vitro

Ranolazine is mainly used to treat patients with chronic stable angina in clinical practice. However, ranolazine does not lower significantly systemic blood pressure. The direct effect of ranolazine on vascular tone remains unknown. In the present study, we investigated the vascular effects and mechanisms of action of ranolazine in isolated rat intrarenal arteries. Rings of intrarenal arteries were mounted in a small vessel myography using two stainless steel wires for the measurement of isometric tension. L-type Ca²⁺ currents were recorded in isolated single renal arterial smooth muscle cells using patch clamp techniques in whole-cell mode. Ranolazine induced concentration-dependent relaxations in rings contracted with phenylephrine, but ranolazine failed to cause any relaxation in rings pre-contracted by U46619, 5-HT or endothelin-1. Ranolazine also induced relaxations in norepinephrine pre-contracted rings. Yohimbine failed to induce relaxation in rings pre-contracted by norepinephrine. Propranolol did not affect ranolazine-induced relaxation but the relaxant effect of ranolazine was much less than that of prazosin. Ranolazine-induced relaxations were slight but significantly attenuated by endothelial denudation. Partial inhibition was observed in endothelium-intact arteries exposed to a combination of iberiotoxin and apamin. Ranolazine at higher concentration (>30 μM) inhibited Ca²⁺-induced contraction in a noncompetitive manner. Ranolazine reduced L-type Ca²⁺ currents at potentials between -30 and 50 mV in isolated renal artery myocytes. Therefore it can be said that ranolazine has significant α₁-adrenergic receptor and weak calcium channel antagonistic effects in rat intrarenal arteries.

Ranolazine improves cardiac diastolic dysfunction through modulation of myofilament calcium sensitivity

RATIONALE

Previously, we demonstrated that a deoxycorticosterone acetate (DOCA)-salt hypertensive mouse model produces cardiac oxidative stress and diastolic dysfunction with preserved systolic function. Oxidative stress has been shown to increase late inward sodium current (I(Na)), reducing the net cytosolic Ca(2+) efflux.

OBJECTIVE

Oxidative stress in the DOCA-salt model may increase late I(Na), resulting in diastolic dysfunction amenable to treatment with ranolazine.

METHODS AND RESULTS

Echocardiography detected evidence of diastolic dysfunction in hypertensive mice that improved after treatment with ranolazine (E/E':sham, 31.9 ± 2.8, sham+ranolazine, 30.2 ± 1.9, DOCA-salt, 41.8 ± 2.6, and DOCA-salt+ranolazine, 31.9 ± 2.6; P=0.018). The end-diastolic pressure-volume relationship slope was elevated in DOCA-salt mice, improving to sham levels with treatment (sham, 0.16 ± 0.01 versus sham+ranolazine, 0.18 ± 0.01 versus DOCA-salt, 0.23 ± 0.2 versus DOCA-salt+ranolazine, 0.17 ± 0.0 1 mm Hg/L; P<0.005). DOCA-salt myocytes demonstrated impaired relaxation, τ, improving with ranolazine (DOCA-salt, 0.18 ± 0.02, DOCA-salt+ranolazine, 0.13 ± 0.01, sham, 0.11 ± 0.01, sham+ranolazine, 0.09 ± 0.02 seconds; P=0.0004). Neither late I(Na) nor the Ca(2+) transients were different from sham myocytes. Detergent extracted fiber bundles from DOCA-salt hearts demonstrated increased myofilament response to Ca(2+) with glutathionylation of myosin binding protein C. Treatment with ranolazine ameliorated the Ca(2+) response and cross-bridge kinetics.

CONCLUSIONS

Diastolic dysfunction could be reversed by ranolazine, probably resulting from a direct effect on myofilaments, indicating that cardiac oxidative stress may mediate diastolic dysfunction through altering the contractile apparatus.

Role of ranolazine in angina, heart failure, arrhythmias, and diabetes

Ranolazine which is currently approved as an antianginal agent reduces the Na-dependent Ca overload via inhibition of the late sodium current (late I(Na)) and thus improves diastolic tone and oxygen handling during myocardial ischemia. According to accumulating evidence ranolazine also exerts beneficial effects on diastolic and systolic heart failure where late I(Na) was also found to be elevated. Moreover, late I(Na) plays a crucial role as an arrhythmic substrate. Ranolazine has been described to have antiarrhythmic effects on ventricular as well as atrial arrhythmias without any proarrythmia or severe organ toxicity as it is common for several antiarrhythmic drugs. In patients with diabetes, treatment with ranolazine led to a significant improvement of glycemic control. In this article possible new clinical indications of the late I(Na)-inhibitor ranolazine are reviewed. We summarize novel experimental and clinical studies and discuss the significance of the available data.

Antiadrenergic and hemodynamic effects of ranolazine in conscious dogs

Effects of ranolazine alone and in the presence of phenylephrine (PE) or isoproterenol (ISO) on hemodynamics, coronary blood flow and heart rate (HR) in the absence and presence of hexamethonium (a ganglionic blocker) were studied in conscious dogs. Ranolazine (0.4, 1.2, 3.6, and 6 mg/kg, intravenous) alone caused transient (<1 minute) and reversible hemodynamic changes. PE (0.3-10 μg/kg) caused a dose-dependent increase in blood pressure and decrease in HR. ISO (0.01-0.3 μg/kg) caused a dose-dependent decrease in blood pressure and an increase in HR. Ranolazine at high (11-13 mM), but not at moderate (4-5 mM) concentrations partially attenuated changes in mean arterial blood pressure and HR caused by either PE or ISO in normal conscious dogs. However, in dogs treated with hexamethonium (20 mg/kg) to cause autonomic blockade, ranolazine (both 4-5 and 11-13 μM) significantly attenuated both the PE- and ISO-induced changes in mean arterial blood pressure. The results suggest that a potential antiadrenergic effect of ranolazine was masked by autonomic control mechanisms in conscious dogs but could be observed when these mechanisms were inhibited (eg, in the hexamethonium-treated dog). Ranolazine, at plasma concentrations <10 μM and in conscious dogs with intact autonomic regulation, had minimal antiadrenergic (α and β) effects.

Class I/B antiarrhythmic property of ranolazine, a novel antianginal agent, in dog and human cardiac preparations

The aim of this study was to investigate the cellular electrophysiological effects of ranolazine on action potential characteristics. The experiments were carried out in dog and human cardiac preparations using the conventional microelectrode technique. In dog Purkinje fibres ranolazine produced a concentration- and frequency-dependent depression of the maximum rate of depolarization (V(max)) while action potential duration (APD) was shortened. In dog and human right ventricular papillary muscle ranolazine exerted no significant effect on APD, while it produced, like mexiletine, use-dependent depression of V(max) with relatively fast onset and offset kinetics. In dog midmyocardial preparations the drug did not exert statistically significant effect on repolarization at 10 μM, although a tendency toward prolongation was observed at 20 μM. A moderate lengthening of APD(90) by ranolazine was noticed in canine atrial preparations obtained from dogs in sinus rhythm and in tachypacing induced remodelled preparations. Use-dependent depression of V(max) was more pronounced in atria from dogs in sinus rhythm than those in remodelled atria or in the ventricle. These findings indicate that ranolazine, in addition to its known late sodium current blocking effect, also depresses peak I(Na) with class I/B antiarrhythmic characteristics. Although peak I(Na) inhibition by ranolazine is stronger in the atria, it is also substantial (at fast stimulation frequencies) in ventricular preparations. Ranolazine also decreased the dispersion of ventricular repolarization (the difference in APD(90) values between Purkinje fibres and papillary muscles), which can contribute to the antiarrhythmic property of the drug.

Y1767C, a novel SCN5A mutation, induces a persistent Na+ current and potentiates ranolazine inhibition of Nav1.5 channels

Long QT syndrome type 3 (LQT3) has been traced to mutations of the cardiac Na(+) channel (Na(v)1.5) that produce persistent Na(+) currents leading to delayed ventricular repolarization and torsades de pointes. We performed mutational analyses of patients suffering from LQTS and characterized the biophysical properties of the mutations that we uncovered. One LQT3 patient carried a mutation in the SCN5A gene in which the cysteine was substituted for a highly conserved tyrosine (Y1767C) located near the cytoplasmic entrance of the Na(v)1.5 channel pore. The wild-type and mutant channels were transiently expressed in tsA201 cells, and Na(+) currents were recorded using the patch-clamp technique. The Y1767C channel produced a persistent Na(+) current, more rapid inactivation, faster recovery from inactivation, and an increased window current. The persistent Na(+) current of the Y1767C channel was blocked by ranolazine but not by many class I antiarrhythmic drugs. The incomplete inactivation, along with the persistent activation of Na(+) channels caused by an overlap of voltage-dependent activation and inactivation, known as window currents, appeared to contribute to the LQTS phenotype in this patient. The blocking effect of ranolazine on the persistent Na(+) current suggested that ranolazine may be an effective therapeutic treatment for patients with this mutation. Our data also revealed the unique role for the Y1767 residue in inactivating and forming the intracellular pore of the Na(v)1.5 channel.

Recent advances in the management of chronic stable angina II. Anti-ischemic therapy, options for refractory angina, risk factor reduction, and revascularization

The objectives in treating angina are relief of pain and prevention of disease progression through risk reduction. Mechanisms, indications, clinical forms, doses, and side effects of the traditional antianginal agents - nitrates, β-blockers, and calcium channel blockers - are reviewed. A number of patients have contraindications or remain unrelieved from anginal discomfort with these drugs. Among newer alternatives, ranolazine, recently approved in the United States, indirectly prevents the intracellular calcium overload involved in cardiac ischemia and is a welcome addition to available treatments. None, however, are disease-modifying agents. Two options for refractory angina, enhanced external counterpulsation and spinal cord stimulation (SCS), are presented in detail. They are both well-studied and are effective means of treating at least some patients with this perplexing form of angina. Traditional modifiable risk factors for coronary artery disease (CAD) - smoking, hypertension, dyslipidemia, diabetes, and obesity - account for most of the population-attributable risk. Individual therapy of high-risk patients differs from population-wide efforts to prevent risk factors from appearing or reducing their severity, in order to lower the national burden of disease. Current American College of Cardiology/American Heart Association guidelines to lower risk in patients with chronic angina are reviewed. The Clinical Outcomes Utilizing Revascularization and Aggressive Drug Evaluation (COURAGE) trial showed that in patients with stable angina, optimal medical therapy alone and percutaneous coronary intervention (PCI) with medical therapy were equal in preventing myocardial infarction and death. The integration of COURAGE results into current practice is discussed. For patients who are unstable, with very high risk, with left main coronary artery lesions, in whom medical therapy fails, and in those with acute coronary syndromes, PCI is indicated. Asymptomatic patients with CAD and those with stable angina may defer intervention without additional risk to see if they will improve on optimum medical therapy. For many patients, coronary artery bypass surgery offers the best opportunity for relieving angina, reducing the need for additional revascularization procedures and improving survival. Optimal medical therapy, percutaneous coronary intervention, and surgery are not competing therapies, but are complementary and form a continuum, each filling an important evidence-based need in modern comprehensive management.

A novel mechanism for the treatment of angina, arrhythmias, and diastolic dysfunction: inhibition of late I(Na) using ranolazine

Inhibition of the persistent or late Na current (INa) using ranolazine (Ranexa) represents a novel mechanism of action that was approved in the United States in 2006 and only recently in the European Union for use in patients with stable angina pectoris. In general, myocardial ischemia is associated with reduced adenosine triphosphate fluxes and decreased energy supply, resulting in severe disturbances of intracellular ion homeostasis in cardiac myocytes. In the recent years, increased late INa was suggested to contribute to this phenomenon by elevating intracellular Na concentration with subsequent rise in diastolic Ca levels by means of the sarcolemmal Na-Ca exchange system. Ranolazine, a specific inhibitor of late INa, reduces Na influx and hence ameliorates disturbed Na and Ca homeostasis. This is associated with a symptomatic improvement of angina in patients unlike other antianginal drugs without affecting heart rate or systemic blood pressure as shown in placebo-controlled studies. Therefore, ranolazine is a useful new option for patients with chronic stable angina not only as an add-on therapy. New clinical and experimental studies even point to potential antiarrhythmic effects, beneficial effects in diastolic heart failure, and under hyperglycemic conditions. In the present article, the relevant pathophysiological concepts for the role of late INa inhibition are reviewed and the most recent data from basic studies and clinical trials are summarized.

Ranolazine, an antianginal agent, markedly reduces ventricular arrhythmias induced by ischemia and ischemia-reperfusion

We tested the effect of the antianginal agent ranolazine on ventricular arrhythmias in an ischemic model using two protocols. In protocol 1, anesthetized rats received either vehicle or ranolazine (10 mg/kg, iv bolus) and were subjected to 5 min of left coronary artery (LCA) occlusion and 5 min of reperfusion with electrocardiogram and blood pressure monitoring. In p rotocol 2, rats received either vehicle or three doses of ranolazine (iv bolus followed by infusion) and 20 min of LCA occlusion. With protocol 1, ventricular tachycardia (VT) occurred in 9/12 (75%) vehicle-treated rats and 1/11 (9%) ranolazine-treated rats during reperfusion ( P = 0.003). Sustained VT occurred in 5/12 (42%) vehicle-treated but 0/11 in ranolazine-treated rats ( P = 0.037). The median number of episodes of VT during reperfusion in vehicle and ranolazine groups was 5.5 and 0, respectively ( P = 0.0006); median duration of VT was 22.2 and 0 s in vehicle and ranolazine rats, respectively ( P = 0.0006). With p rotocol 2, mortality in the vehicle group was 42 vs. 17% ( P = 0.371), 10% ( P = 0.162) and 0% ( P = 0.0373) with ranolazine at plasma concentrations of 2, 4, and 8 μM, respectively. Ranolazine significantly reduced the incidence of ventricular fibrillation [67% in controls vs. 42% ( P = 0.414), 30% ( P = 0.198) and 8% ( P = 0.0094) in ranolazine at 2, 4, and 8 μM, respectively]. Median number (2.5 vs. 0; P = 0.0431) of sustained VT episodes, incidence of sustained VT (83 vs. 33%, P = 0.0361), and the duration of VT per animal (159 vs. 19 s; P = 0.0410) were also significantly reduced by ranolazine at 8 μM. Ranolazine markedly reduced ischemia-reperfusion induced ventricular arrhythmias. Ranolazine demonstrated promising anti-arrhythmic properties that warrant further investigation.

Utility of ranolazine in chronic stable angina patients

Chronic stable angina is a debilitating illness affecting at least 6.6 million US residents. Despite being optimally treated by pharmacotherapy and revascularization up to 26% of patients still experience angina. Diabetes mellitus is a common co-morbid condition in angina patients. Several new investigational medications are being tested for chronic angina. Advances in understanding of myocardial ischemia have prompted evaluation of a number of new antianginal strategies. In this review we discuss the utility of ranolazine, a recently approved novel antianginal agent and its efficacy in the diabetic patient population. In addition to its antianginal action in diabetic patients with chronic angina, ranolazine may have favorable effects on glycated hemoglobin levels.

Ranolazine for chronic stable angina

Ranolazine is a new and unique antianginal drug that has been approved for the treatment of chronic stable angina pectoris. The drug is administered as a sustained-release formulation. Although the drug's mechanism of action has not been fully elucidated, current thinking is that ranolazine, a selective inhibitor of late sodium influx, attenuates the abnormalities of ventricular repolarisation and contractility associated with ischaemia. Three randomised trials have shown efficacy for ranolazine in increasing exercise testing or reducing anginal episodes or use of glyceryl trinitrate. Side-effects include dizziness, constipation, nausea, and the potential for prolongation of the QT(c) interval. Ranolazine seems to be a safe addition to current traditional drugs for chronic stable angina, especially in aggressive multidrug regimens.

Late sodium current inhibition as a new cardioprotective approach

There is increasing evidence that the late sodium current of the sodium channel in myocytes plays a critical role in the pathophysiology of myocardial ischemia and thus is a potential therapeutic target in patients with ischemic heart disease. Ranolazine, an inhibitor of the late sodium current, reduces the frequency and severity of anginal attacks and ST-segment depression in humans, and unlike other antianginal drugs, ranolazine does not alter heart rate or blood pressure. In experimental animal models, ranolazine has been shown to reduce myocardial infarct size and to improve left ventricular function after acute ischemia and chronic heart failure. This article reviews published data describing the role of late sodium current and its inhibition by ranolazine in clinical and experimental studies of myocardial ischemia.

The Antianginal Agent, Ranolazine, Reduces Myocardial Infarct Size but Does Not Alter Anatomic No-Reflow or Regional Myocardial Blood Flow in Ischemia/Reperfusion in the Rabbit

It has been suggested that ranolazine protects the ischemic/reperfused heart by reducing diastolic wall pressure during ischemia. However, there is limited information regarding the effect of ranolazine on the anatomic zone of no-flow in a model of acute myocardial occlusion/reperfusion. Before coronary artery occlusion (CAO), open-chest anesthetized rabbits were assigned to vehicle or ranolazine. Hearts received 60 minutes of CAO and 3 hours reperfusion. Ischemic risk zone was comparable in the 2 groups. Ranolazine significantly reduced infarct size. There was a non-significant trend for the no-reflow defect to be smaller in the ranolazine group. Regional myocardial blood flow was similar in both groups in the risk zone during ischemia and at 3 hours reperfusion. Heart rates were similar in both groups, whereas mean arterial pressure was reduced in the ranolazine group. While ranolazine was effective in reducing myocardial infarct size, the mechanism by which it did this was independent of improving perfusion during either ischemia or reperfusion, suggesting that ranolazine's effect of reducing infarct size involves alternative mechanisms.