Symptoms Of Stable Angina Research Articles

P-203 Associated Factors of Aspirin Resistance in Thais with CAD; A Subgroup Analysis, Royal Thai Army Hospital Experience

The study aim was to investigate the role of high sensitive C-reactive protein (hsCRP), flow-mediated dilatation of brachial artery and coronary artery calcium in the prognosis of patients with suspected CAD. We included 142 consecutive patients with typical stable angina symptoms (90 male subjects and 52 female subjects). We measured the serum hsCRP, coronary artery calcium by electron beam computerized tomography and flow-mediated dilatation of brachial artery. These baseline parameters were correlated to the clinical cardiovascular events within >12 months follow-up period. Compared to male subjects, female subjects were younger and they had less coronary artery calcium. Fewer cardiovascular events were noted in Female group. During the follow-up period up to 50 months (median 27 months), 14 cardiovascular events were recorded (13 in male group and 1 in female group). The male patients with events had elevated baseline hsCRP (0.375±0.37 versus 0.188±0.26mg/dl, p = 0.03). In multivariate Cox-regression analysis, after adjusted with conventional risk factors, flow mediated dilatation and coronary artery calcium, hsCRP was the only independent predictor of cardiovascular events in male subjects. (Relative risk [RR], 1.19; 95% confident interval [CI], 1.036 to 1.389; p = 0.015). (Kaplan-Meier curves). In Conclusion, Gender difference does exist in the atherosclerotic process of the patients with suspected CAD. In male subjects, baseline hsCRP level was still the independent predictor of cardiovascular events.

The ACTION study: nifedipine in patients with symptomatic stable angina and hypertension

Coronary heart disease and cerebrovascular disease continue to be the leading causes of illness and death in adults from developed countries. High blood pressure is the most prevalent cardiovascular risk factor and, in clinical practice, coronary disease and hypertension often occur concurrently. Calcium antagonists are used in the treatment of hypertension and angina. In the mid-1990s there was considerable debate concerning the safety of calcium antagonists in the treatment of cardiovascular disease. A Coronary Disease Trial Investigating Outcome with Nifedipine gastrointestinal therapeutic system (ACTION) study was designed as a consequence of this discussion on calcium antagonists to investigate the effects of the long-acting calcium antagonist nifedipine gastrointestinal therapeutic system on clinical outcomes in patients with stable, symptomatic coronary disease (52% of whom were hypertensive). The aim of this review is to provide an update on the status of the reported ACTION study results from different studies and subgroups.

Ivabradine: the evidence of its therapeutic impact in angina.

Introduction:Stable angina pectoris (SAP) is a widely prevalent disease affecting 30 000 to 40 000 per million people in Europe and the US. SAP is associated with reductions in quality of life and ability to work, and increased use of healthcare resources. Ivabradine is a drug with a unique therapeutic target, the If current of the sinus node, developed for the treatment of cardiovascular diseases including SAP. It has an exclusive heart rate reducing effect, without any negative effect on left ventricular function or coronary vasodilatation.Aims:The aim of this paper is to review the evidence concerning the use of ivabradine in the treatment of SAP.Evidence review:Ivabradine is an effective antianginal and antiischemic drug, not inferior to the beta blocker atenolol and the calcium channel antagonist (CCA) amlodipine. It decreases the frequency of angina attacks and increases the time to anginal symptoms during exercise. Because of its exclusive chronotropic effect, ivabradine is not associated with the typical adverse reactions associated with beta blockers or other antianginal drugs.Clinical value:Clinical evidence shows that ivabradine is a very good antiischemic and antianginal agent, being as effective as beta blockade and CCA therapy in controlling myocardial ischemia and symptoms of stable angina. Ongoing studies will determine the potential of ivabradine to improve morbidity and mortality in coronary artery disease and heart failure.

Nicht-invasive Diagnostik der koronaren Herzkrankheit bei Frauen: Belastungs-EKG oder ST-Strecken-Analyse im Langzeit-EKG?*

The diagnostic value of an exercise ECG in women with the clinical symptoms of stable angina is limited because of its low accuracy in demonstrating coronary heart disease. A study of ambulatory patients was undertaken, involving 143 men and 29 women (mean age 55 [37-70] years), to determine whether ST-segment analysis of the 24-hour ECG gives better results, the coronary arteriogram providing the standard of comparison. 24-hour monitoring and the exercise ECG gave similar diagnostic results (66% vs 67%) in the 143 men. But in the 29 women 24-hour monitoring was diagnostically superior to the exercise ECG (76% vs 45%; P less than 0.01), as a result of a significantly higher specificity (64% vs 29%; P less than 0.05) and a tendency towards higher sensitivity (87% vs 60%; P = 0.13). As expected, the accuracy of the exercise ECG was thus lower in women than in men (P less than 0.05). There were no significant gender-specific differences for accuracy of 24-hour monitoring (76% in women, 66% in men; P less than 0.15). These data indicate that in women ST-segment analysis of the 24-hour ECG is better than the exercise ECG for demonstrating coronary heart disease.

Effectiveness of Psychoeducational Interventions for Improving Symptoms, Health-Related Quality of Life, and Psychological well Being in Patients with Stable Angina.

Several primary trials report the adjunctive value of psychoeducational interventions for improving stable angina symptoms, health-related quality of life (HRQL) and psychological well-being; however, few high-quality meta-analyses have examined the overall effectiveness of these interventions. We used meta-analysis in order to determine the effectiveness of psychoeducational interventions for improving symptoms, HRQL and psychological well-being in stable angina patients. Seven trials, involving 949 participants total were included. Those who received psychoeducation experienced nearly 3 less angina episodes per week, delta (Δ)= -2.85, 95% CI, -4.04 to -1.66, and used sublingual (SL) nitrates approximately 4 times less per week, Δ= -3.69, 95% CI -5.50 to -1.89, post-intervention (3-6 months). Significant HRQL improvements (Seattle Angina Questionnaire) were also found for physical limitation, Δ= 8.00, 95% CI 4.23 to 11.77, and disease perception, Δ= 4.46, 95% CI 0.15 to 8.77, but CIs were broad. A pooled estimate of effect on psychological well-being was not possible due to heterogeneity of measures. Psychoeducational interventions may significantly reduce angina frequency and decrease SL nitrate use in the short-term. These encouraging results must be interpreted with caution due to heterogeneity in methods and small samples. Larger, robust trials are needed to further determine the effectiveness of psychoeducation for stable angina management.

Nifedipine gastrointestinal therapeutic system: an overview of its antiatherosclerotic effects

Atherosclerosis is the main underlying pathology of cardiovascular disease. Experimental studies in animal models provided early evidence of the antiatherosclerotic effects of nifedipine in reducing and reversing plaque formation and improving endothelial function. Over the past decade, clinical trials, including ‘Intervention as a Goal in Hypertension Treatment’, ‘Prospective Randomized Enalapril Study Evaluating Regression of Ventricular Enlargement’, ‘Evaluation of Nifedipine and Cerivastatin on Recovery of Coronary Endothelial Function’ and ‘A Coronary Disease Trial Investigating Outcome with Nifedipine Gastrointestinal System’, have further demonstrated that nifedipine gastrointestinal therapeutic system can slow the progression of various markers of atherosclerosis, restore endothelial function, and reduce the incidence of coronary events and the need for coronary interventions. These results are reviewed here, along with the impact they have had on therapy guidelines for patients with hypertension and symptomatic stable angina.

The recognition of acute coronary ischemia in the outpatient setting

The missed diagnosis of acute myocardial infarction has been studied in the Emergency Department, but few studies have investigated how often coronary ischemia is correctly identified in the outpatient setting. This was a single center retrospective observational study of patients with Health Alliance Plan medical insurance hospitalized at a US tertiary center with acute myocardial infarction in 2004. Outpatient encounters in the 30 days preceding acute myocardial infarction were reviewed by two independent cardiologists for presenting symptoms and diagnostic decision-making in order to classify patient presentations as acute coronary ischemia, stable angina or neither. There were 331 patients with acute myocardial infarction, including 190 (57%) with a primary diagnosis of AMI and evaluated by a physician in the preceding 30 days. This group included 68 patients with 95 documented outpatient encounters by a primary care physician, cardiologist, or other internal medicine specialist which formed the final study population. Mean interval between these encounters and AMI was 17 +/- 11 days. Of these patients, 7 (10%) had symptoms of acute coronary ischemia, 5 (7%) had stable angina symptoms, and 56 (83%) had no symptoms of coronary ischemia at their outpatient encounters. Of the 7 patients with acute coronary ischemic symptoms, 5 were correctly identified and 2 were misidentified. A majority of patients with subsequent AMI visit an outpatient provider in the month preceding AMI. However, few present with symptoms of coronary ischemia in the outpatient setting (10%) and these symptoms are not always identified as such.

Reestenose associada à fratura de stent com liberação de sirolimus

Os autores descrevem um caso de fratura de stent Cypher®. Inicialmente, a fratura foi acompanhada clinicamente (paciente era assintomatico, sem evidencia clara de isquemia a investigacao nao-invasiva). Entretanto, durante seguimento tardio, o paciente passou a apresentar sintomas de angina estavel, necessitando de nova intervencao percutânea e, posteriormente, implante de novo stent farmacologico.

Unidirectional communication between the circumflex and right coronary arteries: a very rare coronary anomaly and cause of ischemia

Intercoronary communication is an exceptionally rare congenital malformation. A 43-year-old male was admitted to our cardiology department with symptomatic stable angina. ECG and echocardiography was normal. Exercise electrocardiography showed ST depression in inferior leads. No atherosclerotic plaque in the coronary arteries was detected on coronary angiography. However, a unidirectional intercoronary communication between the circumflex and right coronary arteries, which was leading a coronary steal from right to left, was observed. Although intercoronary communication is generally not related with ischemia, ischemic symptoms and exercise ECG changes of this case suggested that unidirectional flow might cause myocardial ischemia via coronary steal. Consequently, intercoronary communication, a very rare coronary anomaly and a cause of ischemia, is discussed in this case report.

Effect of Long-Acting Nifedipine on Mortality and Cardiovascular Morbidity in Patients With Symptomatic Stable Angina and Hypertension: The ACTION Trial

Effect of Long-Acting Nifedipine on Mortality and Cardiovascular Morbidity in Patients With Symptomatic Stable Angina and Hypertension: The ACTION Trial

Clinical decision making in patients with stable anginal symptoms: combining functional assessment with morphology to guide treatment

Clinical decision making in patients with stable anginal symptoms: combining functional assessment with morphology to guide treatment

The effects of bivalirudin compared with those of unfractionated heparin plus eptifibatide on inflammation and thrombin generation and activity during coronary intervention

To characterize effects of bivalirudin compared with unfractionated heparin plus eptifibatide on inflammation, and thrombin generation and activity after percutaneous coronary intervention. We measured the concentration in blood of fibrinopeptide A, prothrombin fragment 1+2, soluble CD40 ligand, interleukin 1 receptor antagonist, interleukin 6, and high sensitivity C-reactive protein in 63 patients treated with aspirin and clopidogrel and undergoing elective percutaneous coronary intervention, who were randomized to treatment with either bivalirudin (n=34) or unfractionated heparin plus eptifibatide (n=29). Neither generation nor activity of thrombin increased 10 min after percutaneous coronary intervention in patients randomized to bivalirudin or unfractionated heparin plus eptifibatide. However, prothrombin fragment 1+2 increased modestly and comparably in both groups after 1 day. Inflammation, reflected by concentrations of interleukin 6 and high sensitivity C-reactive protein in blood, increased similarly 1 day after percutaneous coronary intervention in patients treated with either regimen. In a subset of patients (n=12 in each group) from whom blood was obtained 30 days after percutaneous coronary intervention, the concentration of high sensitivity C-reactive protein was lower in those who had been treated with bivalirudin (by 3.5 mg/l, P=0.002). The early effects on inflammation and thrombin generation and activity are similar after treatment with bivalirudin alone compared with unfractionated heparin plus eptifibatide in patients treated with aspirin and clopidogrel who are undergoing percutaneous coronary intervention for symptoms of stable angina. The decreased concentration of high sensitivity C-reactive protein seen 30 days after percutaneous coronary intervention in those treated with bivalirudin is consistent with greater attenuation of inflammation that may have contributed to the trend toward reduced mortality 1 year later in those treated with bivalirudin in REPLACE-2.

Effect of long-acting nifedipine on mortality and cardiovascular morbidity in patients with symptomatic stable angina and hypertension: the ACTION trial

To examine the effects of nifedipine GITS on clinical outcome in patients with concurrent stable angina and hypertension. Data from the double-blind placebo-controlled ACTION trial was stratified for hypertension (blood pressure > or = 140/90 mmHg), at baseline. A total of 52% of 7665 ACTION patients were hypertensive. Some 80% were on a beta blocker; hypertensives were more often treated with other blood pressure-lowering drugs. Mean baseline blood pressure was 122/74 mmHg among normotensives and 151/85 mmHg among hypertensives. Follow-up blood pressures were reduced by nifedipine (P < 0.001) on the average by 3.9/2.4 and 6.6/3.5 mmHg among normotensives and hypertensives, respectively. Nifedipine GITS significantly (P < 0.05) reduced the combined incidence of all-cause mortality, myocardial infarction, refractory angina, heart failure, stroke and peripheral revascularization by 13% in hypertensives only. Nifedipine significantly reduced the incidence of any stroke or transient ischemic attack by almost 30% in both subgroups and the need for coronary angiography by 21% in normotensives and 16% in hypertensives. Among hypertensives, the incidence of new overt heart failure was significantly reduced by 38% and of debilitating stroke by 33%. Among normotensives, the need for coronary bypass grafting was significantly reduced by 32%. Nifedipine did not affect all-cause death, cardiovascular death and myocardial infarction in either normo- or hypertensives, but increased the need for peripheral revascularization. The salutary effects of the addition of nifedipine GITS to the basic regimen of patients with concurrent stable symptomatic coronary artery disease and hypertension emphasize the need for blood pressure control.

Acute coronary lesions and troponin elevation in unstable angina pectoris or non-ST elevation acute myocardial infarction

Angiographic studies support an association between troponin elevation, intracoronary thrombus, and presumed embolization, but previous studies have indicated that only 20% to 25% of patients with positive troponin levels had angiographic evidence of intracoronary thrombus compared with 5% of patients who were troponin negative. 1–3 Although there already exists an association, 75% to 80% of patients with increased troponin levels had no evidence of intracoronary thrombus. It has been previously shown that the angiographic morphology of the culprit lesion in unstable angina pectoris (UAP) or non–Q-wave acute myocardial infarction (AMI) is characteristic, with 50% to 70% of patients having an acute coronary or complex lesion, which is the angiographic correlate of a disrupted or fi ssured atherosclerotic plaque and/or the presence or intracoronary thrombus. 4,5 This lesion is uncommon in culprit lesions from patients presenting with symptoms of stable angina. Therefore, it was hypothesized that this lesion classifi cation system might represent a more sensitive method for examining the association between elevated troponin and the presence of intracoronary thrombus.

Relation of the pattern of diastolic augmentation during a course of enhanced external counterpulsation (EECP) to clinical benefit (from the International EECP Patient Registry [IEPR

E external counterpulsation (EECP) is a noninvasive counterpulsation technique that reduces angina and extends time to exercise-induced ischemia in patients with symptomatic stable angina. In addition to relieving myocardial ischemia, EECP is associated with improved quality of life. It uses a sequential inflation of 3 sets of pneumatic cuffs wrapped around the lower extremities. The cuffs are inflated sequentially at the onset of diastole, producing aortic counterpulsation, diastolic augmentation (DA), and increased venous return. At the onset of systole, external pressure in the cuffs is released, producing a decrease in systolic pressure (systolic unloading). These hemodynamic effects are monitored noninvasively by assessing the finger plethysmographic waveforms. A typical course of EECP involves 1 to 2 hours/day for a total of 35 hours of therapy. It has been hypothesized that the sustained benefits of EECP result from effective DA, which promotes coronary collateral formation or recruitment. A previous study has demonstrated that patients who are younger, male, nonsmoking, and without multivessel coronary or noncardiac vascular disease are most likely to have higher DA at the end of an EECP treatment course. Patients with higher DA ratios at the end of EECP tended to have a greater reduction in angina class than those with lower DA ratios, suggesting that clinical benefit from EECP is associated with the magnitude of DA. That initial study was limited by assessing the DA ratios on the final day of EECP therapy. This present analysis further investigates the role of DA in EECP by assessing the impact of DA levels both at the first and last treatment session with EECP.

Autoantibody against, malondialdehyde-modified low density lipoprotein in patients with non-diabetic unstable angina: a potential role in immunologic reaction of plaque instability.

The role of autoantibody against oxidized low-density lipoprotein (LDL) in the pathogenesis of atherosclerosis is still unknown. The purpose of this study was to determine whether autoantibodies against malondialdehyde (MDA)-modified LDL are associated with coronary artery disease (CAD) and clinical presentations of CAD in non-diabetic patients without acute myocardial infarction (AMI). We determined the serum levels of autoantibody against MDA-modified LDL by ELISA in 71 patients with angiographically significant CAD (> or = 50% diameter stenosis in at least 1 vessel) and 80 controls without angiographically significant CAD. Among the total 151 subjects, 30 subjects did not have any clinical ischemic event, 90 subjects had stable angina symptoms, and 31 subjects had unstable angina symptoms. The autoantibody titer, expressed mean optical density units, was significantly higher in patients with CAD than in controls (0.177 +/- 0.014 versus 0.127 +/- 0.011, respectively; p=0.006) and higher in unstable angina group than in stable angina group (0.240 +/- 0.025 versus 0.145 +/- 0.007, respectively; p < 0.001). By logistic regression analysis, the high autoantibody titer was associated significantly with CAD (P=0.008), independent of age, gender, body mass index, triglyceride concentration, and the ratio of total cholesterol-high density lipoprotein (HDL) cholesterol. In multiple regression analysis, presence of CAD, smoking history and low HDL-cholesterol level were independent factors associated with a increased anti-oxLDL Ab titer. The autoantibody titer was significantly lower in nonsmoker than smoker (p=0.019) and higher in low HDL- cholesterol (< or = 35 mg/dl) group than in high HDL-cholesterol group (p=0.012). Elevated autoantibody titer was associated with CAD and the unstable clinical presentation of CAD. Our results suggest that immune response to oxidized LDL may play a role in the pathogenesis of atherosclerosis and plaque instability.

Enhanced external counterpulsation improved myocardial perfusion and coronary flow reserve in patients with chronic stable angina; evaluation by(13)N-ammonia positron emission tomography.

The mechanism by which enhanced external counterpulsation therapy exerts its beneficial effects on chronic and symptomatic stable angina is largely unknown. To clarify the mechanism of action of enhanced external counterpulsation, we used(13)N-ammonia positron emission tomography to evaluate myocardial perfusion. This was not a randomized controlled study. Eleven patients (eight male, age: 61.6+/-9.7) with angina pectoris underwent enhanced external counterpulsation therapy for 35 1 h sessions. They underwent a treadmill exercise test and(13)N-ammonia positron emission tomography, both at rest and with dipyridamole, before and after enhanced external counterpulsation therapy. Neurohumoral factors and nitric oxide were also evaluated. Myocardial perfusion increased at rest after therapy (0.69+/-0.27 to 0.85+/-0.47 ml x min(-1) x g(-1), P<0.05). In ischaemic regions, particularly the anterior region, myocardial perfusion at rest and with dipyridamole and coronary flow reserve improved significantly after therapy (at rest: 0.71+/-0.26 to 0.86+/-0.31;P<0.05, with dipyridamole: 1.26+/-0.65 to 1.84+/-0.94;P<0.02, coronary flow reserve: 1.75+/-0.24 to 2.08+/-0.28;P<0.04). Exercise time was prolonged and the time to 1-mm ST depression improved markedly (P<0.01). After therapy, nitric oxide levels increased (P<0.02) and neurohumoral factors decreased. Enhanced external counterpulsation therapy improved myocardial perfusion at rest and with dipyridamole and was associated with an increased exercise tolerance with(13)N-ammonia positron emission tomography and increased nitric oxide levels. These results suggest that one of the enhanced external counterpulsation mechanisms is development and recruitment of collateral vessels.

Unstable Angina: Are We Able to Recognize High-Risk Patients?

It is difficult to identify characteristics of patients with unstable angina that are predictive of a high likelihood of developing clinical events. However, several features have been recognized. Patients with a clinical history of previous stable exertional angina symptoms who began to experience rest pain appear to be at risk and tend to have more extensively underlying coronary disease. When the ischemic episodes are accompanied by rates, a new or worsening mitral regurgitation murmur, or hypotension, there is a high likelihood of significant coronary artery disease and one should triage these patients to early cardiac catheterization and prompt revascularization. An angiographic feature that carries a high risk is a lesion in the proximal left anterior descending or in the left main coronary artery. Certain typical ECG patterns are very suggestive for a critical narrowing in these coronary arteries. If chest pain and ST-segment changes recur on vigorous medical management, early invasive evaluation should be strongly considered. Even so, the left ventricular function is very important prognostically. According to serologic tests, the level of C-reactive protein and serum amyloid A protein suggesting that there may be active inflammation predicts an early poor outcome. However, these serologic abnormalities do not have much clinical value. An increased platelet activation and a reduced fibrinolytic capacity play a role in the pathogenesis of unstable angina, but thrombolytic therapy does not improve the prognosis in patients with unstable angina.

760-3 Vibrational Coronary Angioplasty Challenging Chronic Total Occlusions. Preliminary Clinical Data

Vibrational angioplasty is a novel method of angioplasty which is particularly suitable for the treatment of chronic total occlusions. Vibrational angioplasty utilises a hand held motor which is attached to a conventional catheter and guide wire. This device consists of a motor and gearing system producing a fine rapid reciprocation and random motion in a flexible guide wire. In vitro studies have shown that this system generates reciprocal motion in a guide wire with random oscillations of 2 times the reciprocating frequency. The range of movement of the wire is dependant on the frequency of vibration and degree of flexibility of the wire together with the lateral motion of the vibrating ‘shuttle’ ih the device. We present the first 18 cases (12 male 6 female, mean age 59.8 yrs range 40–73) of chronic total occlusion treated with the new version of this device. All patients had symptoms of stable angina. Arteries treated were left anterior descending:8,left circumflex:4, right coronary artery:6. In all 18 cases there was a failure to cross the lesion with conventional techniques and wires. The mean duration of the occlusions was 17.03 months (range:4–60 months). In 16/18 cases successful crossing was achieved with vibration In 2/18 cases where a wire managed to cross the lesion no balloon could subsequently cross the lesion. In 14/18 cases lesions were crossed successfully by a balloon and PTCA was performed with pressure ranging between 2.5–6 Atm. The post procedural result was: uncomplicated in 9/18, complicated by moderate dissection treated conservatively in 1/18 cases, by major dissection needed stenting in 2/18, compromised by the evidence of severe diffuse disease distally in 2/18 and regarded as unsuccessful in 4/18. The total procedural and screening times (mean ± SD) were 73.2 ± 31.3 and 41.2 ± 16.4 min respectively. “vibrational angioplasty” appears to achieve high primary success rates in the recanalisation of totally occluded arteries. Further studies are needed to clarify its mechanism of action, the vessel wall changes due to vibrational energy and their impact on restenosis.

Clinical presentation and functional prognosis in syndrome X.

To assess the effect of clinical presentation on functional prognosis in patients with syndrome X. A prospective study. Patients with syndrome X presenting with unstable angina and stable angina were followed up with a questionnaire to examine their functional state. 41 patients with syndrome X and unstable angina and 41 patients with syndrome X and stable angina. Syndrome X was defined as typical anginal chest pain, a positive exercise test, and normal coronary angiogram. Regional cardiothoracic centre. The mean follow up time was 36 (range 20-51) months for the unstable angina group and 35 (range 19-51) months for the stable angina group. No patient was lost to follow up in either group. At follow up 28 patients in the unstable angina group were pain free compared with 15 patients in the stable angina group (p = 0.008). Seven patients in the unstable angina group had further hospital admission with chest pain after the cardiac catheterisation compared wtih 12 patients in the stable angina group (NS). Seven patients in the unstable angina group believed that they had heart disease compared with 27 in the stable angina group (p < 0.001). 26 patients in the unstable angina group but only eight patients in the stable angina group were unlimited in their physical activity (p < 0.001). 12 patients in the unstable angina group compared with 27 patients in the stable angina group were unable to work normally because of chest pain (p < 0.001). The mean (SD) duration of symptoms before cardiac catheterisation was 7.9 (4.7) months in the unstable angina group and 13.4 (5.6) months in the stable angina group (p < 0.001). 10 patients in the unstable angina group and 24 patients in the stable angina group still attended hospital outpatient clinics because of chest pain (p = 0.004). 16 patients in the unstable angina group and 29 patients in the stable angina group were still taking regular antianginal medication (p < 0.001). Patients with syndrome X who present with unstable angina have a significantly better functional prognosis than those presenting with symptoms of stable angina. This may reflect differences in underlying pathophysiological mechanisms.