Treatment of stable angina

WITHDRAWN: Trimetazidine for stable angina

BACKGROUND

Patients with stable angina not controlled by monotherapy with nitrates, beta blockers, or calcium channel blockers are often treated with combinations of these drugs. There may be adverse effects from, or contraindications to, the use of combinations. In low risk groups, medical treatment appears to be as good an option as percutaneous transluminal coronary angioplasty in terms of averting myocardial infarction, death, or subsequent revascularization. Revascularization procedures are too costly or inaccessible for many patients in developing countries therefore effective and safe medical treatment is needed. Trimetazidine is a less well known anti-anginal drug that controls myocardial ischaemia through intracellular metabolic changes. Trimetazidine has been reported, in some studies, to be better tolerated than combined anti-anginal therapy; however it is not considered in published guidelines.

OBJECTIVES

To determine the efficacy and tolerability of trimetazidine in patients with stable angina.

SEARCH METHODS

We searched The Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, LILACS and SCISEARCH, without language restriction, from inception to October 2003. Experts in the field were contacted to locate unpublished studies.

SELECTION CRITERIA

Randomised studies comparing trimetazidine with placebo, or other anti-angina drug in adults with stable angina.

DATA COLLECTION AND ANALYSIS

Two reviewers independently applied the inclusion criteria, assessed trial quality and extracted data.

MAIN RESULTS

Twenty-three studies (1378 patients) met the inclusion criteria. There was a paucity of information about mortality, cardiovascular events and quality of life. Trimetazidine, compared with placebo, reduced the number of weekly angina attacks ( mean difference -1.44, 95% CI -2.10 to -0.79; P < 0.0001), reduced weekly nitroglycerin tablet consumption (95% CI -1.47 to -2.20, -0.73; P < 0.0001) and improved exercise time to 1 mm segment depression (P = 0.0002). Four small trials (263 patients) compared trimetazidine against other anti-anginal agents. One favoured trimetazidine over nitrates. Three tended to favour alternative regimens but with confidence intervals consistent with both major increases and decreases in frequency of angina episodes. In this subgroup, adverse events were considered in 5 trials (448 patients) and totals of 2 versus 12 drop outs due to adverse events were observed in the trimetazidine and alternative regimens respectively, but this was mostly driven by a single trial.

AUTHORS' CONCLUSIONS

Trimetazidine is effective in the treatment of stable angina compared with placebo, alone or combined with conventional anti-anginal agents. Trimetazidine may result in fewer dropouts due to adverse events. Large, long term trials comparing trimetazidine with other anti-anginal drugs assessing clinically relevant important outcomes are required to establish its role in clinical management.

Pharmacologic management of chronic stable angina

Chronic stable angina is a significant problem in older adults. The goal of therapy is to provide symptomatic relief, improve patient quality of life, and prevent subsequent angina or myocardial infarction that could lead to sudden death. The efficacy and safety of drugs such as beta-blockers and calcium channel blockers for managing chronic stable angina in older adults has not been rigorously investigated. Drug selection should be based on physiologic alterations, patient comorbidities, adverse reaction profile, and cost.

Conventional and novel drug therapeutics to relief myocardial ischemia

Effective management of stable angina usually includes drug therapy. There are several agents that are considered vasculoprotective such as aspirin, angiotensin converting enzyme inhibitors and statins. Conventional anti ischemic therapy includes nitrates, beta-blockers and calcium-channel blockers. In recent years, several other drugs with novel anti ischemic mechanisms have become available including ranolazine, ivabradine, nicorandil and many others. This article reviews drugs that alleviate the symptoms of chronic angina with emphasis on several novel pharmacological agents.

3D QSAR studies on 3,4-dihydroquinazolines as T-type calcium channel blocker by comparative molecular similarity indices analysis (CoMSIA)

A comparative molecular similarity indices analysis (CoMSIA) of a set of 42 3,4-dihydroquinazolines have been performed to find out the pharmacophore elements for T-type calcium channel blocking activity. The most potent compound, 33 (KYS05090) was used to align the molecules. As a result, we obtained 3D QSAR model which provided good predictivity for the training set (q(2)=0.642, r(2)=0.874) and the test set (r(pred)(2)=0.884). This model would guide the design of new chemical entities potentially having high potency.

Chinese herbal medicine suxiao jiuxin wan for angina pectoris

BACKGROUND

Suxiao jiuxin wan is widely used in China for angina pectoris.

OBJECTIVES

The objective of this review is to determine the effects (benefits and harms) of suxiao jiuxin wan in the treatment of angina pectoris.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials on The Cochrane Library (issue 4 2005), Medline (1995 to 2005), EMBASE (1995 to 2005), the Register of Chinese trials developed by the Chinese Cochrane Centre (to 2006), and the Chinese Biomedical Database (1995 to 2005), and handsearched 83 Chinese journals. We also searched reference lists, databases of ongoing trials and the Internet. Date of last search: November 2005.

SELECTION CRITERIA

Randomised controlled trials of suxiao jiuxin wan compared to standard treatment in people with angina. Studies with a treatment duration > 4 weeks were included.

DATA COLLECTION AND ANALYSIS

Two reviewers independently applied the inclusion criteria, assessed trial quality and extracted the data.

MAIN RESULTS

Fifteen trials involving 1776 people were included. There was weak evidence that suxiao jiuxin wan compared with nitroglycerin (xiaoxintong) improved ECG measurements (RR 1.16, 95% CI 1.05 to 1.27), reduced symptoms (RR 1.09, 95% CI 1.04 to 1.13), reduced the frequency of acute attacks of angina (difference in means -0.70, 95% CI -0.90 to -0.50), reduced diastolic pressure (difference in means -3mmHg, 95% CI -5.73 to -0.27) and reduced the need for supplementary nitroglycerin (difference in means of -0.60, 95% CI -0.94 to -0.26). There was also weak evidence that suxiao jiuxin wan compared with Salvia miltiorrhiza (danshen) reduced symptoms (RR 1.21, 95% CI 1.11 to 1.31) and improved ECG measurements (RR 1.55, 95% CI 1.30 to 1.84). There was no significant difference when comparing suxiao jiuxin wan with isosorbide dinitrate (xiaosuanyishanlizhi) both for ECG improvement (RR 1.34, 95% CI 0.91 to 1.98) and for symptom improvement (RR 1.11, 95% CI 0.86 to 1.43).

AUTHORS' CONCLUSIONS

Suxiao jiuxin wan appears to be effective in the treatment of angina pectoris and no serious side effects were identified. However, the evidence remains weak due to poor methodological quality of including studies.

Discovery of potent T-type calcium channel blocker

The intensive SAR study of 3,4-dihydroquinazoline series led to the most potent compound 10 (KYS05090: IC(50)=41+/-1 nM) against T-type calcium channel and its potency is nearly comparable to that of Kurtoxin. As a small organic molecule, this compound showed the highest blocking activity reported to date.

3D pharmacophore based virtual screening of T-type calcium channel blockers

Virtual screening of the commercial databases was done by using a three dimensional pharmacophore previously developed for T-type calcium channel blockers using CATALYSTtrade mark program. Biological evaluation of 25 selected virtual hits resulted in the discovery of a highly potent compound VH04 with IC(50) value of 0.10 microM, eight times as potent as the known selective T-type calcium channel blocker, mibefradil. Search for similar compounds yielded several hits with micro-molar IC(50) values and high T-type calcium channel selectivity. Based on the structure of the virtual hits, small molecule libraries with novel scaffolds were designed, synthesis and biological evaluation of which are currently in progress. This result shows a successful example of ligand based drug discovery of potent T-type calcium channel blockers.

Antianginal Efficacy of Ranolazine When Added to Treatment With Amlodipine

OBJECTIVES

The purpose of this study was to determine if ranolazine improves angina in stable coronary patients with persisting symptoms despite maximum recommended dose of amlodipine.

BACKGROUND

Ranolazine is a unique antianginal agent that has been effective in stable angina, but it has not been studied in the setting of maximum recommended doses of conventional antianginal agents.

METHODS

Stable patients with coronary disease and > or =3 anginal attacks per week despite maximum recommended dosage of amlodipine (10 mg/day) were randomized to 1,000 mg ranolazine or placebo twice a day for 6 weeks. Primary end point was the frequency of angina episodes per week during the double-blind treatment phase. Efficacy was also assessed by nitroglycerin consumption per week and the Seattle Angina Questionnaire (SAQ). Adjustment for multiple testing of secondary end points used a hierarchic closed testing procedure. Efficacy was assessed in subgroups based on baseline angina frequency, concomitant long-acting nitrate use, gender, and age. Safety was assessed by adverse events and electrocardiogram evaluations.

RESULTS

A total of 565 patients were randomized: 281 patients to ranolazine and 284 patients to placebo. Baseline characteristics were similar between treatment groups. At baseline, angina frequency averaged 5.63 +/- 0.18 episodes/week, and nitroglycerin consumption averaged 4.72 +/- 0.21 tablets/week. Compared with placebo, ranolazine significantly reduced frequency of angina episodes (2.88 +/- 0.19 on ranolazine vs. 3.31 +/- 0.22 on placebo; p = 0.028) and nitroglycerin consumption (2.03 +/- 0.20 on ranolazine vs. 2.68 +/- 0.22; p = 0.014), with treatment effect that appeared consistent across subgroups. The median angina weekly episode rate at baseline was 4.5 per week. Subgroup analysis showed statistically significant reductions of angina frequency, nitroglycerin use, and SAQ angina frequency for patients with a baseline frequency >4.5 per week but only of angina frequency for those with baseline frequency < or =4.5 per week. Patients with more frequent angina appeared to have a more pronounced treatment effect. No hemodynamic changes were observed. Ranolazine was well tolerated.

CONCLUSIONS

Ranolazine significantly reduced frequency of angina and nitroglycerin consumption compared with placebo and was well tolerated. (The ERICA [Efficacy of Ranolazine In Chronic Angina] Trial; http://clinicaltrials.gov; NCT00091429).

Angina pectoris: evaluation in the office

Angina pectoris is a clinical manifestation of myocardial ischemia. Complete evaluation consists of a review of risk factors, a careful history, and, typically, a provocative test. Stress testing can be performed with exercise(treadmill, bicycle, or arm ergometry) or pharmacologic agents that increase cardiac work (dobutamine) or dilate the coronary vessels (adenosine or dipyridamole). Patients who have high-risk features found by clinical history or by stress testing should be referred for coronary angiography and possible revascularization. Comprehensive management of patients who have angina (with or without revascularization) includes smoking cessation,diet and weight control, vasculoprotective drugs (aspirin, statins, and possibly ACE inhibitors), and antianginal medications (nitrates, D-blockers, and calcium channel blockers). These strategies have led to an important reduction in morbidity and mortality over the past 2 decades, and the focus on implementing guidelines for patients who are currently undertreated is expected to improve outcomes further.

Selection of optimal therapy for chronic stable angina

Patients with chronic stable angina (CSA) seek a medical opinion for relief of their symptoms and because of fear of having a heart attack. The underlying lesion responsible for CSA is often a severe narrowing of one or more coronary arteries. In addition, the coronary arteries of patients with CSA contain many more nonobstructive lesions, which progress at variable rates, and are prone to rupture and may manifest as acute coronary syndromes (myocardial infarction , unstable angina , or sudden ischemic death). Most patients with CSA can be managed with medical treatment. For angina relief, optimum doses of one of the antianginal drugs (beta blockers , long-acting organic nitrates, or calcium channel blockers ) should be used. If the patient remains symptomatic, combination treatment of BBs plus nitrates or BBs plus dihydropyridine CCBs, or nondihydropyridine CCBs plus nitrates should be tried. Triple therapy has not been shown to be more effective than treatment with two agents. To reduce the incidence of MI, UA, and sudden ischemic death, treatment strategies should include smoking cessation, daily aspirin, daily exercise, and pharmacologic therapy for dyslipidemias, and for elevated blood pressure. Patients who remain symptomatic despite medical therapy and those not willing to take or unable to tolerate antianginal drugs should be considered for percutaneous or surgical coronary revascularization. Patients who do not respond to medical therapy and are not candidates for a revascularization procedure may be considered for additional treatment with trimetazidine or nicorandil (these drugs are not available in the United States or approved by the US Food and Drug Administration, but are available in some other countries). Ranolazine also looks promising but is not yet available for clinical use. As a last resort, enhanced external counterpulsation, spinal cord stimulation, sympathectomy, or direct transmyocardial revascularization should be considered for symptom relief.

Trimetazidine for stable angina

BACKGROUND

Patients with stable angina not controlled by monotherapy with nitrates, beta blockers, or calcium channel blockers are often treated with combinations of these drugs. There may be adverse effects from, or contraindications to, the use of combinations. In low risk groups, medical treatment appears to be as good an option as percutaneous transluminal coronary angioplasty in terms of averting myocardial infarction, death, or subsequent revascularization. Revascularization procedures are too costly or inaccessible for many patients in developing countries therefore effective and safe medical treatment is needed. Trimetazidine is a less well known anti-anginal drug that controls myocardial ischaemia through intracellular metabolic changes. Trimetazidine has been reported, in some studies, to be better tolerated than combined anti-anginal therapy; however it is not considered in published guidelines.

OBJECTIVES

To determine the efficacy and tolerability of trimetazidine in patients with stable angina.

SEARCH STRATEGY

We searched The Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, LILACS and SCISEARCH, without language restriction, from inception to October 2003. Experts in the field were contacted to locate unpublished studies.

SELECTION CRITERIA

Randomised studies comparing trimetazidine with placebo, or other anti-angina drug in adults with stable angina.

DATA COLLECTION AND ANALYSIS

Two reviewers independently applied the inclusion criteria, assessed trial quality and extracted data.

MAIN RESULTS

Twenty-three studies (1378 patients) met the inclusion criteria. There was a paucity of information about mortality, cardiovascular events and quality of life. Trimetazidine, compared with placebo, reduced the number of weekly angina attacks ( mean difference -1.44, 95% CI -2.10 to -0.79; P < 0.0001), reduced weekly nitroglycerin tablet consumption (95% CI -1.47 to -2.20, -0.73; P < 0.0001) and improved exercise time to 1 mm segment depression (P=0.0002). Four small trials (263 patients) compared trimetazidine against other anti-anginal agents. One favoured trimetazidine over nitrates. Three tended to favour alternative regimens but with confidence intervals consistent with both major increases and decreases in frequency of angina episodes. In this subgroup, adverse events were considered in 5 trials (448 patients) and totals of 2 versus 12 drop outs due to adverse events were observed in the trimetazidine and alternative regimens respectively, but this was mostly driven by a single trial.

AUTHORS' CONCLUSIONS

Trimetazidine is effective in the treatment of stable angina compared with placebo, alone or combined with conventional anti-anginal agents. Trimetazidine may result in fewer dropouts due to adverse events. Large, long term trials comparing trimetazidine with other anti-anginal drugs assessing clinically relevant important outcomes are required to establish its role in clinical management.

First pharmacophoric hypothesis for T-type calcium channel blockers

A three-dimensional pharmacophore model was developed for T-type calcium channel blockers in order to map common structural features of highly active compounds by using CATALYST program. In the absence of three dimensional structure based information like binding mode and unavailability of more number of specific T-type calcium channel blockers, this hypothesis which consists of three hydrophobic regions, one hydrogen bond acceptor and one positive ionizable regions will act as a valuable tool in designing new ligands. Further more after the withdrawal of mibefradil, the first marketed T-type calcium channel blocker, due to the drug-drug interactions, there is an urgent need for more work in this interest.

3D QSAR studies on T-type calcium channel blockers using CoMFA and CoMSIA

Comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) were performed on a series of isoxazolyl compounds as a potent T-type calcium channel blockers. A set of 24 structurally similar compounds served to establish the model. Four different conformations of the most active compound were used as template structures for the alignment, three of which were obtained from Catalyst pharmacophore modeling and one by using SYBYL random search option. All CoMFA and CoMSIA models gave cross-validated r(2) (q(2)) value of more than 0.5 and conventional r(2) value of more than 0.85. The predictive ability of the models was validated by an external test set of 10 compounds, which gave satisfactory pred r(2) values ranging from 0.577 to 0.866 for all models. Best predictions were obtained with CoMFA std model of Conformer no: 3 alignment (q(2)=0.756, r(2)=0.963), giving predictive r(2) value of 0.866 for the test set. CoMFA and CoMSIA contour maps were used to analyze the structural features of the ligands accounting for the activity in terms of positively contributing physicochemical properties: steric, electrostatic, hydrophobic and hydrogen bonding fields.

External counterpulsation therapy improves endothelial function in patients with refractory angina pectoris

OBJECTIVES

The goal of this study was to investigate the influence of short-term external counterpulsation (ECP) therapy on flow-mediated dilation (FMD) in patients with coronary artery disease (CAD).

BACKGROUND

In patients with CAD, the vascular endothelium is usually impaired and modification or reversal of endothelial dysfunction may significantly enhance treatment. Although ECP therapy reduces angina and improves exercise tolerance in patients with CAD, its short-term effects on FMD in patients with refractory angina pectoris have not yet been described.

METHODS

We prospectively assessed endothelial function in 20 consecutive CAD patients (15 males), mean age 68 +/- 11 years, with refractory angina pectoris (Canadian Cardiovascular Society [CCS] angina class III to IV), unsuitable for coronary revascularization, before and after ECP, and compared them with 20 age- and gender-matched controls. Endothelium-dependent brachial artery FMD and endothelium-independent nitroglycerin (NTG)-mediated vasodilation were assessed before and after ECP therapy, using high-resolution ultrasound.

RESULTS

External counterpulsation therapy resulted in significant improvement in post-intervention FMD (8.2 +/- 2.1%, p = 0.01), compared with controls (3.1 +/- 2.2%, p = 0.78). There was no significant effect of treatment on NTG-induced vasodilation between ECP and controls (10.7 +/- 2.8% vs. 10.2 +/- 2.4%, p = 0.85). External counterpulsation significantly improved anginal symptoms assessed by reduction in mean sublingual daily nitrate consumption, compared with controls (4.2 +/- 2.7 nitrate tablets vs. 0.4 +/- 0.5 nitrate tablets, p <0.001 and 4.5 +/- 2.3 nitrate tablets vs. 4.4 +/- 2.6 nitrate tablets, p = 0.87, respectively) and in mean CCS angina class compared with controls (3.5 +/- 0.5 vs. 1.9 +/- 0.3, p <0.0001 and 3.3 +/- 0.6 vs. 3.5 +/- 0.5, p = 0.89, respectively).

CONCLUSIONS

External counterpulsation significantly improved vascular endothelial function in CAD patients with refractory angina pectoris, thereby suggesting that improved anginal symptoms may be the result of such a mechanism.

Efficacy of monotherapy compared with combined antianginal drugs in the treatment of chronic stable angina pectoris: a meta-analysis

OBJECTIVE

To determine the relative efficacy of antianginal drugs administered as monotherapy or in combination in patients with chronic stable angina.

METHODS

A meta-analysis was performed on randomized trials, published in English between 1980 and 1999, that directly compared combined treatment and monotherapy. Twenty-two articles were included, all on the comparison of -blocker monotherapies to their combination with a calcium antagonist and 10 on the comparison of calcium antagonist monotherapies to their combination with a -blocker.

RESULTS

Time to 1 mm ST-segment depression, total exercise duration and time to onset of anginal pain were significantly increased with the combined therapy compared to -blocker alone (by 8, 5 and 12%, respectively). Only time to 1 mm ST-segment depression was significantly increased with the combined therapy compared to calcium antagonist alone (by 9%). For all these parameters, the adjusted differences were significant only within 6 h following drug intake and were not significant after 6 h. No analysis of safety data could be performed.

CONCLUSION

As far as exercise testing is concerned, the combination of a calcium antagonist and a -blocker is statistically more effective than either monotherapy. Further studies are needed to confirm the higher efficacy after the first 6 h following drug intake.

Spinal Cord Stimulation: A Comparison of Efficacy versus Other Novel Treatments for Refractory Angina Pectoris

Recently much attention has been directed toward novel treatment alternatives for refractory angina pectoris. Refractory angina is persistent stable class III or IV angina despite maximally tolerated medical treatment in patients with end-stage coronary artery disease. Transmyocardial laser revascularization (TMLR), gene therapy, intermittent urokinase therapy, enhanced external balloon counterpulsation, and spinal cord stimulation have all been employed to treat refractory angina pectoris. TMLR and gene therapy are invasive open-chest procedures that have yielded controversial results. Intermittent urokinase and enhanced external balloon counterpulsation studies have limited follow-up times and require multiple clinic visits for treatment. Spinal cord stimulation has a proven short- and long-term efficacy and cost-effectiveness in the treatment of refractory angina. When compared to coronary artery bypass grafting (CABG), it has been shown to decrease the frequency of anginal attacks and consumption of short-acting nitrates to the same extent in refractory angina. Spinal cord stimulation's safety profile has also been well established and it can be used concurrently with cardiac pacemakers or MRI systems, provided the proper precautions are taken. Since spinal cord stimulation is a minimally invasive procedure with a favorable efficacy and safety profile, it should be considered as a valid treatment alternative after medical management has failed in refractory angina prior to implementing invasive modalities such as TMLR or gene therapy.

Enhanced external counterpulsation improves exercise tolerance, reduces exercise-induced myocardial ischemia and improves left ventricular diastolic filling in patients with coronary artery disease

OBJECTIVES

We examined whether enhanced external counterpulsation (EECP) improves myocardial ischemia, exercise tolerance and cardiac function in patients with coronary artery disease (CAD).

BACKGROUND

Enhanced external counterpulsation reduces angina and improves exercise tolerance in patients with CAD. Some objective improvements of ischemia by EECP have been reported, but they should be confirmed further. Detailed hemodynamic effects of EECP have been less well documented.

METHODS

Enhanced external counterpulsation was performed for a total of 35 h in patients with stable CAD (n = 12) who showed evidence of exercise-induced myocardial ischemia despite conventional medical or surgical therapies. All patients had significant stenotic lesions in major coronary arteries.

RESULTS

Enhanced external counterpulsation improved all exercise test parameters (p < 0.05): exercise duration, time to 1-mm ST segment depression, rate-pressure product at peak exercise and rate-pressure product at 1-mm ST segment depression. Moreover, the prevalence of exercise-induced reversible perfusion defects by thallium scintigraphy decreased after treatment (p < 0.01). Enhanced external counterpulsation did not alter systolic function but improved diastolic filling, left ventricular (LV) end-diastolic pressure (p < 0.05) by cardiac catheterization and LV peak filling rate end-diastolic volume/s (p < 0.01) and time to peak filling rate (p < 0.05) by radionuclide scintigraphy. These hemodynamic improvements were associated with decreased plasma brain natriuretic peptides levels after EECP (p < 0.05).

CONCLUSIONS

Thus, EECP treatment improves exercise tolerance and reduced myocardial ischemia by thallium scintigraphy in association with improved LV diastolic filling in patients with stable CAD.