Unstable angina: natural history and determinants of prognosis

Evidence from a Smoking Management Service in a University Teaching Hospital in Dublin, Ireland monitored by repeat surveys, 1997-2022

St Vincent's University Hospital (SVUH) has a comprehensive smoking management programme and since 1997 has conducted periodic surveys of inpatients, outpatients, staff and visitors to establish prevalence of smoking and associated attitudes towards the hospital's smoke-free campus policy pioneered in 2009. We report trends and describe also the online community stop smoking course (SSC) developed more recently in response to COVID-19. A questionnaire examining attitudes and smoking status was administered by census surveys of inpatients, quota or random sub-sample surveys of staff, and quota surveys with outpatients and visitors in the time period of 1997-2018. Chi square test for trend was used. Smoking rates declined in all groups but significantly so in outpatients (19.5% vs. 10%; p < 0.01), visitors (27.4% vs. 9.5%; p < 0.0001) and staff (30.0% vs. 10.8%; p < 0.0001). Use of E-Cigarettes was low in all cohorts. Rates of smoking were borderline higher in inpatients eligible by income for state-funded General Medical Services (33.2% vs 26.8%, p = 0.099). Support for and awareness of the ban increased over time. Demographic and quit data was compared between participants of in-person or online SSC. The online courses were successful with a maintenance of quit rates (End of Course: 54.7% vs. 55.0%, 1 Month: 50.4% vs. 54.0%, 3 Month: 19.8% vs. 22.5%). While the hospital community's smoking prevalence has decreased over time and attitudes to the smoking ban have been increasingly positive, the campus is not without difficulties in keeping it smoke-free. We continue to advocate for hospital staff support in enacting this flagship initiative.

Potential role for pentoxifylline as an anti‑inflammatory drug for patients with acute coronary syndrome

The link between inflammation and acute coronary syndrome (ACS) remains to be sufficiently elucidated. It has been previously suggested that there is an inflammatory process associated with ACS. Pentoxifylline, a methylxanthine derivate, is known to delay the progression of atherosclerosis and reduce the risk of vascular events, especially by modulating the systemic inflammatory response. The present study is a single-blind, randomized, prospective study of pentoxifylline 400 mg three times a day (TID) added to standard therapy vs. standard therapy plus placebo in ACS patients with non-ST elevation myocardial infarction (NSTEMI). Patients with ACS were randomized to receive standard therapy plus placebo in one arm (group A; aspirin, clopidogrel or ticagrelor, statin) and in the other arm (group B) pentoxifylline 400 mg TID was added to standard therapy. The primary outcome was the rate of major adverse cardiovascular events (MACEs) at 1 year. A total of 500 patients underwent randomization (with 250 assigned to group A and 250 to group B) and were followed-up for a median of 20 months. The mean age of the patients was 62.3±10.3 years, 80.4% were male, 20.8% had diabetes, 49.4% had hypertension, and 42% were currently smoking. The statistical analysis was performed for 209 patients in group A and 210 patients in group B (after dropouts due to study drug discontinuation). A primary endpoint occurred in 12.38% (n=26) of patients in group B, as compared with 15.78% (n=33) of those in group A [relative risk (RR), 0.78; 95% confidence interval (CI), 0.486-0.1.263; P=0.40], including cardiovascular death (RR, 0.93; 95% CI, 0.48-1.80, P=0.84), non-fatal myocardial infarction (RR, 1.1; 95% CI, 0.39-3.39, P=0.78), stroke (RR, 0.99; 95% CI, 0.14-6.99, P=0.99) and coronary revascularization (RR, 0.12; 95% CI, 0.015-0.985, P=0.048). Thus, adding pentoxifylline to standard treatment in patients with ACS did not improve MACE at 1 year but had some benefit on the need for coronary revascularization.

Unstable angina: prognosis of the individual patient

Not all patients diagnosed with unstable angina have the same outcome. Thus, it is incumbent on the physician caring for these patients to try to identify factors that will risk-stratify them. These factors include the degree of coronary angiographic stenosis, the lesion morphology, severity of symptoms, presence or absence of transient myocardial ischemia, and state of left ventricular function. In addition, many other factors including the patient's age, gender, and coexisting medical disorders must be considered when trying to prognosticate an individual patient. Clinical experience indicates that clinical indices that combine information provided by all of the above related variables should have more powerful prognostic significance than any individual variable.

C-reactive protein and coronary artery disease

Evidence suggests that inflammation plays a key role in the pathogenesis of atherosclerosis. The chronic inflammatory process can develop to an acute clinical event by the induction of plaque rupture and therefore cause acute coronary syndromes. The aim of this study was to determine the serum levels of the circulating acute-phase reactant C-reactive protein (CRP), which is a sensitive indicator of inflammation, in patients with chronic stable coronary artery disease (CAD) and acute coronary syndromes (ACS). We studied 56 subjects: 1) 25 consecutive patients (18 men, 7 women; mean age, 68.5 +/- 14.3 years, range, 40-86) with unstable angina (UA) or acute myocardial infarction (AMI); 2) 31 consecutive patients (25 men, 6 women; mean age 64 +/- 12.7; range, 47-83, years) with signs and symptoms of clinically stable CAD. High-sensitivity-C-reactive protein (hs-CRP) levels were determined with a commercially available enzyme-linked immunoassay method. In patients with unstable angina and AMI before reperfusion therapy, CRP levels were not significantly different to those in patients with stable CAD (5.96 +/- 2.26 versus 4.35 +/- 2.6 mg/L; P = 0.12), but tended to be higher in patients with unstable angina and AMI. Baseline CRP levels in the subgroup of patients with AMI (6.49 +/- 2.28 mg/L) were significantly higher than levels in patients with stable CAD (4.35 +/- 2.6 mg/L; P = 0.02). CRP levels in patients with unstable angina and AMI were measured four times during a 72-hour period (0, 12, 24, and 72 hours). The lowest value was observed at baseline and differed significantly from values measured at any other time of the observation period (P < 0.001; 5.96 +/- 2.26; 9.5 +/- 9.04, 18.25 +/- 11.02; 20.25 +/- 10.61). CRP levels after 12, 24, and 72 hours were also significantly different to the initial values for patients with stable CAD (P < 0.01). There was no correlation between CRP and creatine kinase (CK), CK-MB isoenzyme, or troponin I positivity as markers for the extent of the myocardial injury during the observation period. Baseline levels of serum CRP tended to be higher in patients with unstable angina or AMI but were not significantly different from levels in patients with chronic stable CAD. In the subgroup of patients with AMI, baseline CRP levels were significantly higher than the levels in patients with stable CAD. CRP as a marker of inflammation is significantly increased in patients with AMI and unstable angina shortly after the onset of symptoms (after a period of 12 hours), supporting the hypothesis of an activation of inflammatory mechanisms in patients with an acute coronary syndrome or AMI.

Inflammation in acute coronary syndromes

Extensive evidence supports a pathogenic role for both local and systemic inflammation in acute coronary syndromes. However, several important questions remain unanswered. Is the observed inflammatory process a precursor or a consequence of coronary plaque rupture? Is the inflammatory component of unstable coronary disease a potential therapeutic target? Finally, do infectious agents have a pathogenic role in coronary atherosclerosis and acute coronary syndromes?

It is safe to manage selected patients with acute coronary syndromes in unmonitored beds

This prospective, observational study evaluated the safety of the Western Hospital admission protocol for patients with suspected acute coronary syndromes. The study included all patients admitted from the Emergency Department with an admission diagnosis of unstable angina, post infarct angina, atypical chest pain, or chest pain for evaluation. Data collected included demographic data, admission diagnosis, location of admission (bed with or without cardiac monitoring), past medical history and presenting chest pain history to determine Agency for Health Care Policy (AHCPR) and Western Hospital (WH) protocol classifications, cardiac enzyme assays, electrocardiogram analysis, adverse outcomes [death, myocardial infarction (MI), dysrhythmia, acute pulmonary edema, recurrent pain], diagnosis at hospital discharge, and length of stay-(LOS). There were 508 patients with a mean age of 63.7 years enrolled in the study. Three hundred nineteen (62.8%) were admitted to beds without any cardiac monitoring. There was one unexpected death in the unmonitored group, an 85 year-old patient who suffered a presumed dysrhythmia and whom the treating physician had decided was not for resuscitation. Twelve patients suffered nonfatal MI, and none suffered pulmonary edema. All MI patients made an uneventful recovery, and none required thrombolysis. If all patients had been admitted to an area of care based on AHCPR guidelines, an additional 310 admissions to monitored beds would have been required. The results of this study suggest that selected patients with suspected acute coronary syndromes can be safely managed in beds without continuous cardiac monitoring.

The prognostic value of small-sized platelet aggregates in unstable angina: detection by a novel laser-light scattering method

Platelet activation plays a pivotal role in the pathogenesis of acute coronary syndromes. This study was designed to evaluate the platelet aggregability in patients with unstable angina using a new aggregometer with laser-light scattering. We also examined whether there was a relationship between these platelet aggregabilities and unfavorable outcome during in-hospital stay. We measured platelet aggregability, in particular small-sized platelet aggregates in 31 patients with unstable angina, 31 patients with stable exertional angina, and 30 patients with chest pain syndrome. The patients with unstable angina were divided into two groups by their cardiac events during in-hospital stay, cardiac events (+)(n=11) group and cardiac events (-)(n=20) group. On admission, the number of small-sized platelet aggregates (V) was higher in patients with unstable angina (3.0+/-0.5x10(4)) than in those with stable exertional angina (1.4+/-0.3x10(4), P=.017) and chest pain syndrome (0.7+/-0.2x10(4), P=.0003). The number of small-sized platelet aggregates was higher in the cardiac events (+) group than in the cardiac events (-) group (5.5+/-0.9x10(4) vs. 1.6+/-0.4x10(4), P=.0001). A previous study elucidated that small-sized platelet aggregates ultimately developed into medium-sized and large-sized aggregates as platelet aggregation proceeds. Therefore, the production of small-sized platelet aggregates is more sensitive for hyperaggregability. Furthermore, the production of small-sized platelet aggregates increased significantly in patients with unstable angina than in those with stable exertional angina and chest pain syndrome. These findings suggest that a tendency toward thrombus formation increases markedly in patients with unstable angina and increased number of small-sized platelet aggregates on admission predicts poor prognosis during in-hospital stay in patients with unstable angina.

Dobutamine stress echocardiography and exercise electrocardiography for risk stratification in medically treated unstable angina

Previous reports have demonstrated the superiority of exercise echocardiography over exercise electro-cardiography (ex-ECG) for risk stratification in patients with medically stabilized unstable angina (UA). We sought to analyze the prognostic value of dobutamine stress echocardiography (DSE) compared with ex-ECG for risk stratification in patients with UA.

METHODS

Ninety-two patients with medically treated UA were studied (mean age 65 +/- 11 years, 24 women, 42% of patients had electrocardiographic abnormalities on admission). Dobutamine stress echocardiography and treadmill ex-ECG were performed on the third day after hospital admission. End points were recurrent UA, myocardial infarction (MI), or cardiac death.

RESULTS

Mean follow-up was 24 +/- 7 months. During follow-up, 22 patients had cardiac events (18 recurrent UA, 2 MI, 2 cardiac deaths). The event-free survival rate was 80% for patients with negative DSE results for ischemia and 52% for those with positive DSE results (log rank 9.57; P =.002), compared with an event-free survival rate of 79% for patients with negative ex-ECG results and 66% for those with positive ex-ECG results (log rank 2.06; P = not significant). Left ventricular dysfunction (P =.01) and a positive dobutamine stress echocardiogram (P =.03), but not a positive exercise electrocardiogram, were independent predictors of cardiac events during follow-up.

CONCLUSIONS

Dobutamine stress echocardiography performed early in medically treated patients with UA predicts cardiac events during follow-up more accurately and with more specificity than ex-ECG does in this population.

QT interval dispersion: non-invasive marker of ischemic injury in patients with unstable angina pectoris?

Prognostic assessment of unstable angina pectoris is a common clinical problem for physicians. Markers of myocardial cell injury, serial electrocardiographic findings and ST segment monitoring are mainly studied for prognosis. We investigated the relation between myocardial injury and the value of cardiac troponin T and QT interval dispersion in hospitalized unstable angina patients. This is a prospective study that includes adult patients admitted to an emergency department with Braunwald class IIIB unstable angina pectoris. Eighty-six patients were enrolled in the study (mean age of 57 +/- 12 years, 63 males and 23 females). Cardiac troponin T was assayed and QT dispersion calculated from surface ECG. Fifty-eight patients with troponin T < 0.1 ng/ml and 28 patients with troponin T levels > or = 0.1 formed group 1 and group 2, respectively. There were no significant differences in sex, age, history of coronary revascularization or ECG findings such as ST depression and T inversions between the two groups. The QT dispersion was significantly greater in patients with elevated cardiac troponin T levels (77 +/- 18 msec vs 38 +/- 13 mse; p < 0.014). Because QT interval dispersion exhibited an association with cardiac troponin T levels, it may be used as a non-invasive marker of ischemic injury in patients with unstable angina.

The health care burden of unstable angina

Worldwide, UA represents a significant allocation of resources. UA represents a syndrome where not only do many therapies exist, but considerable clinical trial evidence has accumulated. Universal application of effective practice patterns is warranted if we are to successfully reduce the burden of UA. Economic analyses cannot resolve many of the underlying societal issues that affect decision making. Often, the acceptability of an economic burden is dependent on the willingness of both individuals and society to pay. In an interesting study, Chestnut et al evaluated the willingness of 50 patients to pay for avoiding a worsening of their angina symptoms. On average, the patients were willing to pay between $210 and $499 to avoid four to eight additional angina episodes each month. The "rule of rescue" suggests that society is often willing to pay large sums of money to save those in extreme need, such as the 55-year-old man rushed to the emergency department clutching his chest. Only recently has attention been paid to how much this disease entity costs us. Whereas the 1980s and 1990s saw a focus on costs, the next century will increasingly focus on value--obtaining the best health outcome for the dollars spent. Debate has shifted, at least in part, from purely financial costs to medical effectiveness and outcomes management. Continuing assessments of value of interventions and application of evidence based-management strategies permit rational selection of therapy and allow us best to bear the burden of UA.

Interesting cases from the University of Texas Medical Branch

This article discusses the cases for four patients with unstable angina. The first case is an example of the "high-risk" patient with widespread ECG changes, heart failure, and enzymatic elevations during an episode of chest pain. The second patient illustrates an unusual cause of unstable angina in a young women. The third patient had a large thrombus visible on angiography and management strategies for dealing with intracoronary thrombus are discussed. The final patient had an extensive past cardiac history with two prior coronary artery bypass operations and we discuss the recent advances made in the treatment of degenerative vein graft disease.

Elevated cardiac troponin I predicts a high-risk angiographic anatomy of the culprit lesion in unstable angina

BACKGROUND

This study assessed the relation between the angiographic appearance of the culprit lesion and cardiac troponin I (cTnI) or C-reactive protein (CRP) elevations within the first 24 hours in unstable angina. Intracoronary thrombus or a complex morphology, is frequently observed on angiography in patients with unstable angina and is associated with a higher rate of spontaneous or coronary angioplasty-related complications. Biochemical parameters related to myocardial injury (eg, cTnI) or to systemic inflammation (eg, CRP) are known prognostic markers for clinical outcome and may help in angiographic risk stratification to provide new adjunctive therapy.

METHODS AND RESULTS

We studied 100 patients admitted for unstable angina with angiographically proven coronary artery disease (with normal creatine kinase [CK] and CK-MB mass). Serum concentrations of cTnI (N < 0.4 ng/mL) and CRP (N < 3 mg/L) were measured at admission and 12 and 24 hours later. Multivariate analysis showed that elevated cTnI (>/=0.4 ng/mL) within 24 hours (35 patients) was an independent predictor of an angiographic appearance of the culprit lesion carrying a high risk of major cardiac events in the outcome and whether angioplasty is attempted (coronary thrombus, occlusion, or type C lesions; odds ratio 4.1, 1. 6 to 10.5). cTnI levels at admission and CRP at 0, 12, and 24 hours were not predictive of high-risk angiographic anatomy.

CONCLUSIONS

In patients with unstable angina and angiographically proven coronary artery disease, increased cTnI within 24 hours of admission but not increased CRP is associated with an angiographic appearance of the culprit lesion carrying a high risk of complication, especially in the event of angioplasty.

Clinical predictors of in-hospital prognosis in unstable angina: ECLA 3. The ECLA Collaborative Group

OBJECTIVES

Because of recent changes in the treatment of unstable angina, we wanted to reassess the short-term prognostic value of clinical and echocardiographic variables.

METHODS

This was an observational, prospective study that included 1038 nonselected consecutive patients admitted to coronary care units for unstable angina.

RESULTS

Baseline characteristics were age 60.18 +/- 16 years, history of prior myocardial infarction in 336 patients (32%), and a history of previous angina in 817 patients (78.7%). Angina during the 48 hours before admission was observed in 1004 patients (96.7%) and ST-segment changes on admission electrocardiogram occurred in 385 patients (37%). In-hospital treatment consisted of nitrates in 81.4% of patients, aspirin in 88.6%, beta-blockers in 71%, intravenous heparin in 34.5%, subcutaneous heparin in 23%, and angioplasty or coronary artery bypass grafting in 25.1%. After admission, angina occurred in 443 patients (40.8%), refractory angina in 223 patients (21.5%), and death or myocardial infarction in 84 patients (8.1%). At admission, the independent predictors of myocardial infarction or death identified by multivariate logistic regression analysis were ST-segment depression (odds ratio [OR] 2.13, 95% confidence interval [CI] 1.23 to 3.68, P =.006), prior angina (OR 2.23, 95% CI 0.98 to 5.05, P =.05), number of episodes of angina within the previous 48 hours (OR 1.63, 95% CI 0.98 to 2.70, P =.05), and history of smoking (OR 0.69, 95% CI 0.56 to 0.85, P =.004). Age greater than 65 years (OR 1.49, 95% CI1.09 to 2.03, P = 0.03) was significantly related to in-hospital death. The area under the receiver operating characteristic curve for application of this model was 0.59. Sensitivity was 80% with a specificity of only 33%. Refractory angina after admission showed a strong relation with an adverse short-term outcome.

CONCLUSIONS

With current therapy, clinical and electrocardiographic variables provide useful information about the short-term outcome of unstable angina. However, this model has low specificity to identify high-risk patients. Future studies about the incremental value of the new serum markers such as troponin T and C-reactive protein to assist in identification of high-risk patients are necessary.

Comparison of the prognostic value of C-reactive protein and troponin I in patients with unstable angina pectoris

This study assessed the prognostic value of cardiac troponin I (cTnI) and C-reactive protein (CRP) in unstable angina, and specifically in patients with angiographically proven coronary artery disease. These biochemical parameters, which are related to myocardial injury or to systemic inflammation, may help in short-term risk stratification of unstable angina. We prospectively studied 195 patients with unstable angina, 100 of whom had angiographically proven coronary artery disease (with normal creatine kinase [CK] and CK-MB mass). Serum concentrations of cTnI (N < 0.4 ng/ml) and CRP (N < 3 mg/L) were measured at admission, 12, and 24 hours later. The rate of in-hospital major adverse cardiac events (death, myocardial infarction, or emergency revascularization) was higher in patients with increased cTnI within the first 24 hours, regardless of the results of coronary angiography (23% vs 7%; p < 0.001). Conversely, events occurred at similar rates in patients with or without increased CRP. In patients with angiographic evidence of coronary artery disease, multivariate analysis showed that increased cTnI within 24 hours of admission (35 patients) was an independent predictor of major adverse cardiac events (odds ratio 6.7, range 1.7 to 27.3), but not cTnI levels at admission and CRP at 0, 12, and 24 hours. Thus, both in unselected patients with unstable angina and in patients with angiographically proven coronary artery disease, increased cTnI within 24 hours of admission, but not CRP, is a predictor of in-hospital clinical outcome. We also found a temporal link between cTnI increase and late elevation of CRP, suggesting that systemic inflammation may partially be a consequence of myocardial injury.

Incremental prognostic value of serum levels of troponin T and C-reactive protein on admission in patients with unstable angina pectoris

Management of unstable angina is largely determined by symptoms, yet some symptomatic patients stabilize, whereas others develop myocardial infarction after waning of symptoms. Therefore, markers of short-term risk, available on admission, are needed. The value of 4 prognostic indicators available on admission (pain in the last 24 hours, electrocardiogram [ECG], troponin T, and C-reactive protein [CRP]), and of Holter monitoring available during the subsequent 24 hours was analyzed in 102 patients with Braunwald class IIIB unstable angina hospitalized in 4 centers. The patients were divided into 3 groups: group 1, 27 with pain during the last 24 hours and ischemic electrocardiographic changes; group 2, 45 with pain or electrocardiographic changes; group 3, 30 with neither pain nor electrocardiographic changes. Troponin T, CRP, ECG on admission, and Holter monitoring were analyzed blindly in the core laboratory. Fifteen patients developed myocardial infarction: 22% in group 1, 13% in group 2, and 10% in group 3. Twenty-eight patients underwent revascularization: 37% in group 1, 35% in group 2, and 7% in group 2 (p <0.01 between groups 1 or 2 vs group 3). Myocardial infarction was more frequent in patients with elevated troponin T (50% vs 9%, p=0.001) and elevated CRP (24% vs 4%, p= 0.01). Positive troponin T or CRP identified all myocardial infarctions in group 3. Only 1 of 46 patients with negative troponin T and CRP developed myocardial infarction. Among the indicators available on admission, multivariate analysis showed that troponin T (p=0.02) and CRP (p=0.04) were independently associated with myocardial infarction. Troponin T had the highest specificity (92%), and CRP the highest sensitivity (87%). Positive results on Holter monitoring were also associated with myocardial infarction (p=0.003), but when added to troponin T and CRP, increased specificity and positive predictive value by only 3%. Thus, in patients with class IIIB unstable angina, among data potentially available on admission, serum levels of troponin T and CRP have a significantly greater prognostic accuracy than symptoms and ECGs. Holter monitoring, available 24 hours later, adds no significant information.

Prognosis of medically stabilized unstable angina pectoris with a negative exercise test

Three hundred twenty seven patients with medically stabilized unstable angina and a negative exercise test were followed-up during a mean of 39 months. Male gender, diabetes mellitus, and previous myocardial infarction, but not exercise parameters, were predictors of death or acute myocardial infarction.

Predictors of multivessel disease in cases of acute chest pain

BACKGROUND

Patients with unstable angina not showing ischemia at the exercise treadmill test after medical stabilization usually have a low-risk coronary anatomy. However, some of them have multivessel disease, and it is not known what characteristics are associated with the extension of the coronary artery disease in this subset of patients.

OBJECTIVE

To determine clinical and exertional characteristics associated with multivessel disease in patients with unstable angina and a negative exercise test.

METHODS

312 hospitalised patients with unstable angina and a negative exercise test who had undergone cardiac catheterization were reviewed. The relationship between coronariographic findings (presence of multivessel disease) and clinical characteristics, exercise parameters and left ventricular function was studied.

RESULTS

Multivessel disease was present in 97 patients (31%). The following variables were associated with the presence of multivessel disease: age more than 65 years old, previous myocardial infarction, previous admissions because of unstable angina, peripheral artery disease, presence of more than two coronary risk factors, left ventricular dysfunction, functional capacity less than 6 METS, duration of exercise less than 8 min and less than 85% of the maximum heart rate. Multivariate analysis showed, as independent predictors of multivessel disease: previous myocardial infarction, previous admissions because of unstable angina, presence of more than two coronary risk factors and peripheral artery disease.

CONCLUSIONS

In patients with medically stabilized unstable angina and a negative exercise test, previous myocardial infarction, previous admissions because of unstable angina, presence of more than two coronary risk factors and peripheral artery disease, but not exercise parameters, are independent predictors of multivessel disease.

C-reactive protein elevation and early outcome in patients with unstable angina pectoris

C-reactive protein, a reactant of the acute phase of inflammation, has been shown to be increased in patients with unstable angina. Moreover, it has recently been found that increased C-reactive protein is associated with a poor outcome during hospitalization in selected patients with severe unstable angina. The aim of this study was to investigate the prognostic value of C-reactive protein elevation in a large population with unstable angina. We measured serum levels of this marker in 140 patients hospitalized with unstable angina (class IIIB of the Braunwald classification, mean time from last anginal episode 5 +/- 5 hours). Thirty-nine of them (28%) had increased serum levels on hospital admission and 33 (24%) experienced an adverse outcome (myocardial infarction or refractory angina) during hospitalization. Kaplan-Meier analysis showed that the probability of developing cardiac events during hospitalization was not different between patients with and without abnormal C-reactive protein levels. Furthermore, the incidence of ischemia at Holter monitoring during the first 72 hours after hospitalization was not different between patients with and without abnormal C-reactive protein. In a representative population of patients with unstable angina, a sizable proportion had increased serum C-reactive protein levels; however, abnormal concentrations of C-reactive protein do not predict an adverse outcome in the early phase after the acute episode.

Predictive validity of the Braunwald classification of unstable angina for angiographic findings, short-term prognoses, and treatment selection

The authors tested the Braunwald classification for its predictive validity for underlying coronary conditions, clinical courses, and responses to treatment. A reliable definition and classification of unstable angina is needed to help physicians make correct diagnoses of patients' conditions and to appraise findings from clinical trials critically. Many clinical trials have been conducted, but it is difficult to compare the results because of different entry criteria. Of 113 consecutive patients admitted with unstable angina, 89 who had primary angina were studied. Braunwald's classification was applied at admission. The outcomes of interest during hospitalization were coronary angiographic findings, short-term prognoses, and the treatment selected. Multivariate analysis showed that the severity class expressed significant positive predictivity for coronary thrombi (adjusted odds ratio [OR], 6.53; 95% confidence interval [CI], 2.82 to 15.1) and progress to impending infarction (OR, 10.43; CI, 3.35 to 32.49). The treatment (OR, 0.02; CI, 0.004 to 0.08) and electrocardiographic (OR, 0.22; CI 0.10 to 0.49) classes showed independent negative predictivity for coronary vasospasm. The treatment (OR, 3.50; CI, 1.94 to 6.33) and electrocardiographic (odds ratio, 3.27; CI, 1.87 to 5.71) classes showed positive predictivity for the necessity for recanalization treatment with coronary angioplasty or bypass grafting. The Braunwald classification used at admission is highly predictive of underlying coronary conditions, progression to impending infarction, and the final selection of treatment. This classification should be considered in determining patient eligibility in clinical trials and studies.

Prospective study of the role of cardiac troponin T in patients admitted with unstable angina

OBJECTIVE

To examine the prognostic significance and role in risk stratification of the biochemical marker troponin T in patients admitted with unstable angina.

DESIGN

Single centre, blinded, prospective study of patients admitted with chest pain.

SETTING

Coronary care unit of a district general hospital.

SUBJECTS

460 patients admitted with chest pain and followed up for a median of three years. 183 patients had a final diagnosis of unstable angina.

MAIN OUTCOME MEASURES

Cardiac death, need for coronary revascularisation, or readmission with non-fatal myocardial infarction as first events.

RESULTS

62 (34%) unstable angina patients were troponin T positive. This group had significantly increased incidence rates of subsequent cardiac death (12 cases (19%) v 14 (12%)), coronary revascularisation (22 (35%) v 26 (21%)), death or revascularisation (33 (53%) v 40 (33%)), and death or non-fatal myocardial infarction (18 (29%) v 21 (17%)) compared with the troponin T negative group. In multiple logistic regression troponin T status was a highly significant predictor for the end points coronary revascularisation and cardiac death or revascularisation as first events.

CONCLUSION

Troponin T in the serum of patients with unstable angina identifies a subgroup at higher risk of subsequent cardiac events and its measurement aids in risk factor stratification. The increased risk extends to two years after admission. Prospective randomised trials are required to identify optimum therapeutic strategies for this subgroup.

The prognostic value of serum troponin T in unstable angina

BACKGROUND

Cardiac troponin T is a regulatory contractile protein not normally found in blood. Its detection in the circulation has been shown to be a sensitive and specific marker for myocardial cell damage. We used a newly developed enzyme immunoassay for troponin T to determine whether its presence in the serum of patients with unstable angina was a prognostic indicator.

METHODS

We screened 72 patients with unstable angina (Class III, acute unstable angina) for serum creatine kinase activity, creatine kinase myocardial band (isoenzyme M) activity, and troponin T, every 8 h for 2 days after admission to the hospital. The outcomes of interest during the hospitalization were death and myocardial infarction.

RESULTS

Troponin T was detected in the serum of 24 of the 72 patients (34%) with acute angina at rest. Only four of these patients had elevated creatine kinase M activity. Of the 24 patients who were positive for troponin T, 12 had myocardial infarction, and 6 of these died during hospitalization. In contrast, only 2 of the 48 patients with angina at rest who were negative for troponin T had an acute myocardial infarction, and these patients died. Thus, 12 of the 14 patients with myocardial infarctions had detectable levels of troponin T; only 2 had elevated creatine kinase M activity.

CONCLUSIONS

Cardiac troponin T in serum appears to be a more sensitive indicator of myocardial-cell injury than serum creatine kinase MB activity, and its detection in the circulation may be a useful prognostic indicator in patients with unstable angina.

Angiographic stenosis progression and coronary events in patients with 'stabilized' unstable angina

BACKGROUND

Recent studies suggest that angiographically complex coronary stenoses are associated with an adverse short-term outcome. It is not known, however, if this applies to unstable angina patients who stabilize on medical therapy.

METHODS AND RESULTS

We prospectively studied 85 consecutive patients with unstable angina who stabilized on medical therapy but were found to require angioplasty for treatment of obstructive coronary disease. Angiography was carried out at admission, and patients were restudied 8 +/- 4 months (mean +/- SD) after the first angiogram. Ischemia-related stenoses were identified and classified as "complex" (irregular borders, overhanging edges, or thrombus) or "smooth" (absence of complex features). Stenosis progression (> or = 20% diameter reduction or new total occlusion) was assessed by automated edge detection. At initial angiography, there were 198 stenoses (> or = 50%, 102), of which 85 (54 complex and 31 smooth) were ischemia related. At restudy, 21 ischemia-related stenoses and 8 non-ischemia-related stenoses progressed (25% versus 7%, P = .001). Seventeen of the 21 ischemia-related stenoses that progressed developed into total occlusion compared with 3 of the 8 non-ischemia-related stenoses (P = .02). Changes in average stenosis severity and in absolute stenosis diameter were significantly larger in ischemia-related stenoses than in non-ischemia-related stenoses (P = .03). Eighteen (34%) complex stenoses progressed, compared with 3 (10%) smooth lesions (P = .02). During follow-up, 1 patient died (myocardial infarction) and 25 patients had nonfatal coronary events that were associated with progression of ischemia-related stenoses in 14 (56%).

CONCLUSIONS

In unstable angina patients who stabilize medically, subsequent short-term stenosis progression and coronary events are common. The unstable coronary lesion (particularly complex stenoses) is often not stabilized and will continue to progress over the ensuing months.

Incidence and follow-up of Braunwald subgroups in unstable angina pectoris

OBJECTIVES

This study was performed to establish the prognosis of patients with unstable angina within the subgroups of the Braunwald classification.

BACKGROUND

Among many classifications of unstable angina, the Braunwald classification is frequently used. However, the incidence and risk for each subgroup in clinical practice have not been established.

METHODS

Prospective data for 417 consecutive patients admitted for suspected unstable angina were analyzed. Patients were classified according to Braunwald criteria and followed up for 6 months. Survival, infarct-free survival and infarct-free survival without intervention are reported for each class.

RESULTS

After in-hospital observation the final diagnosis was acute myocardial infarction in 26 patients (6%), noncoronary chest pain in 109 (26%) and definite unstable angina in 282 (68%). Recurrence of chest pain was significantly different for the different severity classes (28%, 45% and 64% for classes I [accelerated angina], II [subacute angina at rest] and III [acute angina at rest], respectively) but not for clinical circumstances (49% and 53% for classes B [primary unstable angina] and C [postinfarction unstable angina], respectively). Six-month and infarct-free survival (96% and 88%, respectively) were not significantly different between severity classes but were significantly different (p = 0.01) between classes B (97% and 89%) and C (89% and 80%). Infarct-free survival without intervention was best for class II (72%), intermediate for class I (53%) and worst for class III (35%). In multivariate analysis, elderly age, male gender, hypertension, class C and maximal (intravenous) therapy were independent predictors for death; elderly age and class C for infarct-free survival; and male gender, class III, class C, electrocardiographic changes and maximal therapy were associated with infarct-free survival without intervention.

CONCLUSIONS

Braunwald classification is an appropriate instrument to predict outcome. Risk stratification by these criteria provides a tool for patient selection in clinical trials and for evaluation of treatment strategies.

Relation of severity of symptoms to transient myocardial ischemia and prognosis in unstable angina

OBJECTIVES

This study was undertaken to compare the relative power of the severity of angina versus that of any other clinical, electrocardiographic (ECG) and angiographic findings in predicting the risk of subsequent in-hospital coronary events in patients admitted to the coronary care unit for treatment of unstable angina.

BACKGROUND

The presence or absence of chest pain has traditionally been used to guide management and therapy of unstable angina. However, recent studies raised the possibility that the cumulative duration of ischemia may be an additional index of prognosis.

METHODS

We studied 104 consecutive patients admitted to the coronary care unit because of unstable angina. Diaries of symptoms were accurately kept. All patients underwent Holter ambulatory ECG monitoring during the 1st 24 h and angiography within 1 week of admission.

RESULTS

During the hospital stay, 41 patients (group 1) had subsequent coronary events; the remaining 63 patients (group 2) had a good clinical outcome. Recurrence of chest pain after admission was observed in 76% of patients: 36 of the 41 group 1 patients (sensitivity 88%) and 43 of the 63 group 2 patients (specificity 32%). Anginal scores (frequency and persistence of pain, duration of each single episode and pain-free interval) showed high specificity but low sensitivity for detecting evolution toward subsequent coronary events. On Holter monitoring, the duration/24 h of the total number of ischemic episodes was consistently greater in group 1 than in group 2. A cumulative duration of ischemia > or = 60 min/24 h was observed in 34 of the 41 group 1 patients (sensitivity 83%) but in only 16 of the 63 group 2 patients (specificity 75%). High risk coronary artery lesions (left main coronary artery disease or complex stenosis) were detected in 36 of the 41 group 1 patients and in 26 of the 63 group 2 patients.

CONCLUSIONS

Transient myocardial ischemia detected by Holter monitoring, but not chest pain, is the best predictor of unfavorable short-term clinical outcome. The decision to perform early angiography and revascularization cannot be based on symptoms alone.

Noninvasive testing in the diagnosis and management of unstable angina

Patients presenting with a clinical diagnosis of unstable angina comprise a heterogenous population and a wide spectrum of patients with varying degrees of underlying coronary artery disease, severity and prognosis are categorized in this syndrome. A very small number of patients with unstable angina who are refractory to adequate in-hospital medical therapy should undergo urgent coronary angiography and, if suitable, revascularization. The vast majority of patients do, however, stabilize on medical therapy and an invasive approach, such as a coronary angiography should not be performed routinely to all of these patients. Early recognition of clinical and non-invasive test variables indicating an adverse outcome is of paramount importance in unstable angina. This review focuses on the importance of baseline clinical markers and the usefulness of a non-invasive approach with exercise testing, myocardial perfusion imaging, stress echocardiography, and Holter monitoring in the diagnosis, risk stratification, and management of patients with unstable angina.

Clinical features and prognostic implications of myocardial ischemia at rest in patients with exertional angina pectoris

The prognosis of patients with coronary artery disease (CAD) is mainly influenced by organic factors such as cardiac muscle loss and extent of CAD. The aim of this study was to investigate whether a functional factor--reversible myocardial ischemia at rest--plays an independent prognostic role. Thus, 2 groups of patients were studied and followed up for 46 +/- 32 months: 1 group (483 patients) had ischemic electrocardiographic changes only on effort and another group (224 patients) both on effort and at rest. The 2 groups did not differ significantly as to age, gender, coronary risk factors, baseline electrocardiographic abnormalities, incidence of previous myocardial infarction, angiographic left ventricular dysfunction, and extent of coronary stenoses (> or = 50% diameter reduction). There were 65 deaths (40 of which were from cardiac causes) during the 5-year follow-up. Despite the similar incidence of known predictors of prognosis, Kaplan-Meier survival analysis revealed a significantly lower 5-year survival rate in patients with mixed (84.4%) rather than exertional (92.1%) ischemia (p < 0.05 by Mantel-Haenszel test). If only cardiac causes of deaths were considered, the 5-year survival rate was still lower in patients with mixed (89.6%) rather than exertional (93.9%) ischemia. Finally, reversible ischemia at rest was an independent predictor of survival by Cox multivariate regression analysis, preceded only by the extent of CAD and left ventricular dysfunction. Thus, reversible ischemia at rest plays an independent negative role in the long-term clinical outcome of patients with CAD and positive exercise stress test results.

The prognostic value of C-reactive protein and serum amyloid a protein in severe unstable angina

BACKGROUND

The pathogenesis of unstable angina is poorly understood, and predicting the prognosis at the time of hospital admission is problematic. Recent evidence suggests that there may be active inflammation, possibly in the coronary arteries, in this syndrome. We therefore studied the prognostic value of measurements of the circulating acute-phase reactants C-reactive protein and serum amyloid A protein, which are sensitive indicators of inflammation.

METHODS

We measured C-reactive protein, serum amyloid A protein, creatine kinase, and cardiac troponin T in 32 patients with chronic stable angina, 31 patients with severe unstable angina, and 29 patients with acute myocardial infarction.

RESULTS

At the time of hospital admission, creatine kinase and cardiac troponin T levels were normal in all the patients, but the levels of C-reactive protein and serum amyloid A protein were > or = 0.3 mg per deciliter (exceeding the 90th percentile of the normal distribution) in 4 of the patients with stable angina (13 percent), 20 of the patients with unstable angina (65 percent), and 22 of the patients with acute myocardial infarction (76 percent). The 20 patients with unstable angina who had levels of C-reactive protein and serum amyloid A protein > or = 0.3 mg per deciliter had more ischemic episodes in the hospital than those with levels < 0.3 mg per deciliter (mean [+/- SD] number of episodes per patient, 4.8 +/- 2.5 vs. 1.8 +/- 2.4; P = 0.004); 5 patients subsequently had a myocardial infarction, 2 died, and 12 required immediate coronary revascularization. In contrast, no deaths or myocardial infarction occurred among the 11 patients with levels of C-reactive protein and serum amyloid A protein < 0.3 mg per deciliter, and only 2 of them required coronary revascularization. Among the patients admitted with a diagnosis of acute myocardial infarction, unstable angina preceded infarction in 14 of the 22 patients (64 percent) with levels of C-reactive protein and serum amyloid A protein > or = 0.3 mg per deciliter but in none of the 7 patients with levels < 0.3 mg per deciliter.

CONCLUSIONS

Elevation of the sensitive acute-phase proteins C-reactive protein and serum amyloid A protein at the time of hospital admission predicts a poor outcome in patients with unstable angina and may reflect an important inflammatory component in the pathogenesis of this condition.

Unstable angina: prognosis, noninvasive risk assessment, and strategies for management

Risk stratification in patients with unstable angina is a major clinical problem with important therapeutic implications. Antiplatelet therapy is clearly effective in reducing the occurrence of myocardial infarction and death in this syndrome. Interventions including coronary bypass surgery and coronary angioplasty are frequently recommended for these patients, but the most appropriate application of these techniques needs to be further defined. After a brief discussion of the value of medical and interventional therapies, this review focuses on the clinical and noninvasive predictors of adverse events in unstable angina. An overall management strategy for these patients, based on current information, will be proposed.

Remodeling health care

Standard models of patient demand for health care and health care suppliers' response to that demand imply that some manner of manipulation of the prices faced by patients must be chief among the mechanisms of systemic cost control. However convenient econometrically, these standard models cannot reflect the complexity of patient demand behavior, and they say little about the predominant causes of health-care cost escalation. This paper describes a richer Jevonian political-economic model that sensibly portrays patient demand and physician and corporate supply behaviors and suggests a range of cost-controlling and care-enhancing compensatory steps, some professional, some societal. This new model implies that reformers in the United States could take respectful advantage of the fundamentally self-regulating nature of patient demand for health care by shifting their attention away from its further discouragement and toward the modulation of other factors.

Role of nitrates in unstable angina pectoris

Unstable angina pectoris is a clinically heterogeneous process with patient symptoms varying between reduced threshold for exertional angina and the occurrence of multiple episodes of rest pain. The major factors in the pathogenesis of unstable angina appear to be intracoronary platelet aggregation and thrombus formation secondary to fissuring or rupture of atheromatous plaques, with associated coronary vasoconstriction due to release of constrictor materials from aggregating platelets and deficiency of endothelium-related vasodilator activity. The latter factor is of particular interest in view of the similar biochemical mechanisms of action of nitroglycerin (NTG) and endothelium-derived relaxing factor (EDRF). The efficacy of NTG in limiting platelet aggregation is also of particular interest in this condition. Medical therapy in patients with unstable angina usually requires use of multiple agents. In the short term, there is a strong case for the use of intravenous heparin both to relieve pain and to reduce the risk of acute myocardial infarction. Aspirin is perhaps less effective in the short term, but very useful in long-term treatment of such patients. Despite their widespread clinical use, beta-adrenoceptor antagonists are probably only marginally beneficial, whereas dihydropyridine calcium antagonists such as nifedipine are potentially harmful as monotherapy and of questionable use in combination with other drugs. Other agents that are effective in relieving ischemic symptoms are the nondihydropyridine calcium antagonists verapamil and diltiazem and the oxygen-sparing agent perhexiline maleate. Despite a paucity of controlled trial data, nitrates are used in the vast majority of patients with unstable angina.

The prognostic value of serum troponin T in unstable angina

BACKGROUND

Cardiac troponin T is a regulatory contractile protein not normally found in blood. Its detection in the circulation has been shown to be a sensitive and specific marker for myocardial cell damage. We used a newly developed enzyme immunoassay for troponin T to determine whether its presence in the serum of patients with unstable angina was a prognostic indicator.

METHODS

We screened 109 patients with unstable angina (25 with accelerated or subacute angina and 84 with acute angina at rest) for serum creatine kinase activity, creatine kinase isoenzyme MB activity, and troponin T every eight hours for two days after admission to the hospital. The outcomes of interest during the hospitalization were death and myocardial infarction.

RESULTS

Troponin T was detected (range, 0.20 to 3.64 micrograms per liter; mean, 0.78; median, 0.50) in the serum of 33 of the 84 patients (39 percent) with acute angina at rest. Only three of these patients had elevated creatine kinase MB activity (two were positive for troponin T, and one was negative). Of the 33 patients who were positive for troponin T, 10 (30 percent) had myocardial infarction (3 after coronary-artery bypass surgery), and 5 of these died during hospitalization. In contrast, only 1 of the 51 patients with angina at rest who were negative for troponin T had an acute myocardial infarction (P less than 0.001), and this patient died (P = 0.03). Thus, 10 of the 11 patients with myocardial infarctions had detectable levels of troponin T; only 1 had elevated creatine kinase MB activity. Troponin T was not detected in any of the 25 patients with accelerated or subacute angina, and none of these patients died.

CONCLUSIONS

Cardiac troponin T in serum appears to be a more sensitive indicator of myocardial-cell injury than serum creatine kinase MB activity, and its detection in the circulation may be a useful prognostic indicator in patients with unstable angina.

Unstable angina: outcome according to clinical presentation

Unstable angina is a broad clinical diagnosis that includes patients at different levels of risk for an unfavorable outcome. Although, as in other categories of coronary artery disease, the state of left ventricular function and the extent of coronary artery disease will determine long-term prognosis, recognition of clinical markers of an early unfavorable course may be of value in defining management strategies. This review focuses on the relevance of baseline clinical characteristics and noninvasive data in assessing the prognostic significance of unstable angina in light of its presenting features. Recurrence of chest pain within 48 h after admission carries a reduction in likelihood of survival of about 20% in patients with progressive or prolonged angina. Similarly, ECG changes on admission have a negative prognostic implication, particularly in rest angina, as they predict recurrence of ischemia, myocardial infarction or need for revascularization in 80% of the patients. In variant angina, determinants of prognosis are level of disease activity, as judged by recurrence of pain, ECG changes and use of calcium channel antagonists. Patients with angina after a myocardial infarction who have more than one episode of either angina or silent ischemia in 24 h have a 10% reduction in probability of survival during the 1st year compared with that of asymptomatic patients. An abrupt course, or the rapidity with which symptoms develop, is the main determinant of prognosis in new onset angina. Thus, recurrent angina and ECG changes appear to be relevant prognostic markers in the patient subsets considered; if these are present, early coronary angiography must be performed and revascularization procedures should be considered without delay.

Predictors of risk in patients with unstable angina admitted to a district general hospital

OBJECTIVE

To observe the long-term prognosis of patients with unstable angina and select simple criteria to identify high and low risk subgroups.

DESIGN

A six month prospective survey with three year follow up.

SETTING

One eleven bed coronary care unit.

PATIENTS

All patients admitted with chest pain in whom no infarct was confirmed by subsequent electrocardiographic or enzyme changes and for whom no alternative cause of chest pain was found were studied. Unstable angina was also diagnosed if there was evidence of myocardial ischaemia in the form of previous effort angina, previous myocardial infarction, or if transient electrocardiographic changes accompanied the pain. When none of the above were present, chest pain without a known cause, was diagnosed.

INTERVENTIONS

No routine intervention. Angiography and revascularisation for persistent symptoms despite medical treatment.

OUTCOME MEASURES

Death or non-fatal infarction.

RESULTS

In the 141 patients with unstable angina there were eight deaths and five non-fatal infarctions during the first eight weeks. Symptoms of increasing angina before admission were similar in all three groups and did not help predict early complications. Recurrence of pain in hospital, a rise in cardiac enzymes to less than twice the upper limit of normal, and transient electrocardiographic changes were all associated with an increased risk of early events. The presence of either abnormal enzyme activity or more than five episodes of pain in hospital identified a group of 49 in whom 11 of the 13 early events occurred. After three years, 29 of the 141 patients had died and eight had had infarctions (overall event rate 26%). Seventeen had undergone revascularisation (12%) and 51 (36%) were on antianginal treatment. Thirty six (26%) were still alive, without new myocardial infarction, and were free of angina. In the 29 patients with chest pain without a known cause there were no early events and only one non-fatal infarction during the three year follow up.

CONCLUSION

When patients are admitted to the coronary care unit with chest pain not due to myocardial infarction, the history, electrocardiography and measurement of cardiac enzymes are sufficient to identify high and low risk subgroups.

Pharmacotherapy of unstable angina

All patients with unstable angina should be admitted to a coronary or an intensive care unit. There should be an attempt to classify the patient according to the proposed Braunwald nomenclature. If the patient has a secondary cause for unstable angina (e.g., tachyarrhythmia, heart failure, fever, thyrotoxicosis, severe hypertension, hypoxia, unusual emotional stress, or anemia), this condition should be treated initially with therapy specific for that etiology. If the patient does not have a secondary etiology, therapy should be initiated with nitrates, preferably intravenous nitroglycerin. Heparin should be concomitantly administered. If the patient cannot receive heparin, aspirin should be initiated. All patients should receive beta-blockers. If the patient cannot take a beta-blocker, a calcium antagonist (probably diltiazem) should be initiated. However, if the patient is refractory to beta-blockers, the dihydropyridine nifedipine should be added. Failure to all pharmacologic interventions necessitates a progressive invasive approach dictated by the potential surgical risk of the patient. Long-term aspirin and beta-blockers should be strongly considered.

Percutaneous transluminal coronary angioplasty for unstable angina

Coronary angioplasty is an effective treatment for patients with angina at rest, either refractory or initially stabilized but returning despite pharmacologic treatment, and with early postinfarction angina. The procedure has a high initial success rate, but there is an increased risk of major complications resulting from a higher incidence of acute closure, which may be related to preexisting thrombus. Resolution of this problem may be achieved by the use of more potent antiplatelet treatment, pretreatment with thrombolytic agents, or treatment that can be applied locally (e.g., laser energy, atherectomy) at the site of the unstable plaque. Results in this study have been obtained from selected groups of patients: those with predominantly single-vessel disease and well-preserved left ventricular function. It remains to be determined whether the same benefits can be achieved in patients with multivessel disease or in those who have severely reduced left ventricular function.

Higher recurrence rate after coronary angioplasty in unstable angina pectoris

PURPOSE

Recurrent stenosis after percutaneous transluminal coronary angioplasty (PTCA) is a significant problem, requiring repeat dilation in about one-third of all treated patients. Various clinical and procedure-related predictors have been proposed. Between 1983 and 1987, 257 patients underwent 322 procedures, where 380 stenoses were attempted. Indications were: stable angina pectoris 73%, unstable angina pectoris 22%, other indication 5%. The primary success rate was defined as a less than 50% remaining postprocedure stenosis.

FINDINGS

Repeat angiograms were done for 88% of the initially successful cases, either six months after PTCA or if there was a clinical recurrence. Restenosis was defined as a recurrence of a more than 50% diameter stenosis. The restenosis rate was 33% and was significantly higher (p less than 0.05) for unstable (46%) than for stable angina pectoris (29%). There was a nonsignificant tendency to a higher restenosis rate in the left anterior descending artery than in the other coronary vessels.

IMPLICATIONS

The increased restenosis rate seen after PTCA for unstable angina pectoris could be caused by a higher activity in systems affecting the proliferative processes in the smooth muscle cells of the arterial wall, which is thought to form the pathophysiologic basis for restenosis after PTCA.

Intracoronary urokinase for intracoronary thrombus accumulation complicating percutaneous transluminal coronary angioplasty in acute ischemic syndromes

Intracoronary urokinase was used to treat flow-limiting intracoronary thrombus accumulation that complicated successful percutaneous transluminal coronary angioplasty (PTCA) during acute ischemic syndromes in 48 patients who were followed up through the acute phase of their illness. The study group comprised 10 patients with unstable angina pectoris, 18 patients with an evolving acute myocardial infarction, and 20 patients with postinfarction angina. The initial mean percent coronary diameter stenosis for the entire population was 95 +/- 7% and decreased with initial PTCA to 41 +/- 20% (p less than 0.001), with improved corresponding coronary flow by Thrombolysis in Myocardial Infarction trial (TIMI) grade. However, thrombus accumulation then resulted in a significant increase in percent diameter stenosis to 83 +/- 17% (p less than 0.001); a corresponding significant reduction in coronary flow also occurred by TIMI grade. After administration of intracoronary urokinase (mean dose, 141,000 units; range, 100,000-250,000 units during an average period of 34 minutes), with additional PTCA, mean percent diameter stenosis significantly decreased to 34 +/- 17% (p less than 0.001); a correspondingly significant improvement in mean coronary flow by TIMI grade occurred to 2.9 +/- 0.2. Overall, the angiographic success rate was 90%. There were no ischemic events requiring repeat PTCA and no procedure-related myocardial infarctions or deaths before hospital discharge. One patient was referred for urgent coronary artery bypass graft surgery after a successful PTCA. Plasma fibrinogen levels were obtained in 15 patients, and in no patient was the level below normal for our laboratory.(ABSTRACT TRUNCATED AT 250 WORDS)

Recombinant tissue-type plasminogen activator followed by heparin compared with heparin alone for refractory unstable angina pectoris

Patients with unstable angina pectoris who remain symptomatic despite medical treatment are at high risk of death and myocardial infarction. The incidence of refractory unstable angina was examined in a consecutive series of 103 patients who received conventional medical treatment with nitrates, beta blockers, calcium antagonists and aspirin. During 48 hours of continuous electrocardiographic monitoring, 24 patients had greater than or equal to 1 anginal attack, 5 of whom had both painful and painless ischemic episodes. In these 24 patients with unstable angina refractory to conventional medical treatment, the short-term efficacy of recombinant tissue-type plasminogen activator (rt-PA) followed by heparin was assessed and compared with heparin alone in a randomized double-blind trial. Recurrences of ischemic attacks during a 72-hour follow-up period were documented in 9 of the 12 patients given heparin alone. All patients experienced at least 1 symptomatic ischemic episode and 1 patient had both painful and painless ischemia. No patient given rt-PA plus heparin had either symptomatic or asymptomatic ischemic attacks during follow-up. Kaplan-Meier curves analysis demonstrated a significantly higher probability of being ischemia free in the group of patients treated with rt-PA followed by heparin than in the group treated with heparin alone (p less than 0.01). Quantitative coronary arteriography failed to reveal any significant changes of ischemia-related lesions before and after each treatment. This study demonstrates that the combination of rt-PA and heparin has a greater protective effect than heparin alone in treating recurrent ischemic episodes in patients with refractory unstable angina.(ABSTRACT TRUNCATED AT 250 WORDS)

Unstable angina pectoris

The pathophysiology of unstable angina has been better elucidated in the past five years and has led to more rational therapy. Coronary arteries in patients with unstable angina have atherosclerotic plaques which are often complex and are the site of platelet activation and fibrin deposition. Nitrates, one of the oldest therapies, are efficacious and act not only by dilating coronary vessels but by reducing preload and afterload. Beta blockers have a salutary effect by decreasing myocardial oxygen demand. Calcium channel blockers attenuate smooth muscle contraction and thereby act to decrease coronary artery spasm. Beta blockers and calcium channel blockers are equally efficacious in unstable angina. The antiplatelet agent, aspirin, has been shown to reduce fatal or non-fatal myocardial infarction and probably overall mortality. The use of heparin acutely for unstable angina has been demonstrated to decrease refractory angina and myocardial infarction, and acutely is probably better than aspirin. For patients with reduced ejection fractions (0.30-0.49), a prospective randomized trial has shown that coronary artery bypass graft surgery offers an improved three-year survival compared with medical therapy; however, surgery does not prevent myocardial infarction. Percutaneous transluminal coronary angioplasty may be a reasonable therapeutic alternative for some patients with single-vessel disease who are refractory to medical therapy but there are as yet no controlled trials of this question. To date a clinical benefit from thrombolytic therapy has not been demonstrated.

Does intensive medical therapy influence the outcome in unstable angina?

Three hundred and forty-six patients of all ages and both sexes were admitted to coronary care with documented unstable angina. Management was conservative, without the routine use of beta-blockers or calcium antagonists. Mortality was 3.2%, and the nonfatal myocardial infarction rate was 10.1% during the first 28 days. After one year, coronary mortality was 10.5% with a nonfatal infarction rate of 13.1%. Twenty-six patients were subjected to coronary artery bypass surgery, eleven during the first 28 days and fifteen subsequently. No patient underwent coronary angioplasty. The factors influencing immediate and long-term prognosis in these patients were studied. Persistence of pain in hospital, previous chronic angina, and age had an adverse effect on outcome. A total of 143 patients complained of persistent pain lasting for 24 hours or more. The use of beta blockers or calcium antagonists in patients with persistent pain exceeding five days did not appear to influence outcome. The current widespread adherence to "intensive medical treatment," including the routine use of beta blockers and calcium antagonists, is questioned.

Comparison of the natural history of new onset and exacerbated chronic ischemic heart disease. The Chest Pain Study Group

To compare the natural history of patients with new onset ischemic heart disease with that of patients with exacerbations of chronic ischemic heart disease, short- and long-term outcomes of 3,465 emergency room patients with acute ischemic heart disease at four community and three university hospitals were evaluated. Acute myocardial infarction was diagnosed in 598 (33%) of the 1,835 patients with a prior history of infarction or angina and 934 (57%) of the 1,630 without such a history (p less than 0.001). Patients with new onset ischemic heart disease with acute myocardial infarction were more likely than patients with infarction and exacerbated chronic ischemic heart disease to have Q wave infarction (57% versus 36%) and to receive thrombolytic therapy (11% versus 5%); they also had higher maximal creatine kinase levels (1,088 +/- 1,299 versus 733 +/- 906 U/liter) (p less than 0.0001 for all three). After adjustment for differences in clinical presentation and initial triage, patients with new onset ischemic heart disease with acute myocardial infarction were less likely than the comparison group to have congestive complications (odds ratio 0.63, 95% confidence interval 0.47 to 0.84, p less than 0.01) but not less likely to have arrhythmic, ischemic or overall complications. Among patients with angina without acute myocardial infarction, patients with new onset ischemic heart disease were less likely to have recurrent ischemic pain and congestive heart failure. In multivariate analysis of long-term follow-up data on 457 patients from one hospital, patients with new onset ischemic heart disease had better cardiovascular survival rates.(ABSTRACT TRUNCATED AT 250 WORDS)

Antiplatelet treatment with ticlopidine in unstable angina. A controlled multicenter clinical trial. The Studio della Ticlopidina nell'Angina Instabile Group

We conducted a controlled multicenter trial with central randomization and evaluation of events under blind conditions involving 652 patients with unstable angina. Patients were treated either with conventional therapy alone (group C) (n = 338) or with conventional therapy combined with an inhibitor of platelet aggregation, ticlopidine 250 mg b.i.d. (group C + T) (n = 314). Patients were assigned randomly within 48 hours of admission and followed up for 6 months. With the "intention-to-treat" approach, the primary end points, vascular death and nonfatal myocardial infarction, were observed in 13.6% of the patients in group C and in 7.3% of the patients in group C + T, which is a reduction in risk of 46.3% (p = 0.009). Vascular mortality was 4.7% in patients in group C and 2.5% in patients in group C + T, which is a reduction in risk of 46.8% (p = 0.139). The risk of nonfatal myocardial infarction was reduced by 46.1% (p = 0.039), with a frequency of 8.9% in patients in group C and 4.8% in patients in group C + T. New Q wave myocardial infarction occurred with a frequency of 6.8% in patients in group C and 3.8% in patients in group C + T, which is a reduction in risk of 44.1% (p = 0.091). Fatal and nonfatal myocardial infarction was 10.9% in patients in group C and 5.1% in patients in group C + T, which is a reduction in risk of 53.2% (p = 0.006). These findings confirm the importance of platelets in the pathogenesis of unstable angina and the usefulness of antiplatelet treatment for the prevention of cardiovascular events.