Development and evaluation of the Seattle Angina Questionnaire: a new functional status measure for coronary artery disease

OBJECTIVES

This study sought to establish the validity, reproducibility and responsiveness of the Seattle Angina Questionnaire, a 19-item self-administered questionnaire measuring five dimensions of coronary artery disease: physical limitation, anginal stability, anginal frequency, treatment satisfaction and disease perception.

BACKGROUND

Assessing the functional status of patients is becoming increasingly important in both clinical research and quality assurance programs. No current functional status measure quantifies all of the important domains affected by coronary artery disease.

METHODS

Cross-sectional or serial administration of the Seattle Angina Questionnaire was carried out in four groups of patients: 70 undergoing exercise treadmill testing, 58 undergoing coronary angioplasty, 160 with initially stable coronary artery disease and an additional 84 with coronary artery disease. Evidence of validity was sought by comparing the questionnaire's five scales with the duration of exercise treadmill tests, physician diagnoses, nitroglycerin refills and other validated instruments. Reproducibility and responsiveness were assessed by comparing serial responses over a 3-month interval.

RESULTS

All five scales correlated significantly with other measures of diagnosis and patient function (r = 0.31 to 0.70, p < or = 0.001). Questionnaire responses of patients with stable coronary artery disease did not change over 3 months. The questionnaire was sensitive to both dramatic clinical change, as seen after successful coronary angioplasty, and to more subtle clinical change, as seen among outpatients with initially stable coronary artery disease.

CONCLUSIONS

The Seattle Angina Questionnaire is a valid and reliable instrument that measures five clinically important dimensions of health in patients with coronary artery disease. It is sensitive to clinical change and should be a valuable measure of outcome in cardiovascular research.

Coronary angioscopy in patients with unstable angina pectoris

To visualize intracoronary lesions in patients with different clinical expressions of coronary disease, we performed coronary angioscopy during coronary-artery bypass surgery in 10 patients with unstable angina and 10 patients with stable coronary disease. We examined a total of 32 vessels, using flexible fiberoptic angioscopes. Twenty-two vessels had no acute intimal lesion; three had complex plaques, six had thrombi, and one had both. Coronary angiography correctly identified the absence of complex plaque and thrombus in 22 vessels, but it detected only one of four complex plaques and one of seven thrombi. On angioscopy, none of the 17 arteries in the patients with stable coronary disease had either a complex plaque or thrombus. In the "offending" arteries of the patients with unstable angina, all three patients with accelerated angina had complex plaques and all seven with angina at rest had thrombi. We conclude that angioscopy frequently reveals complex plaques or thrombi not detected by coronary angiography. Our observations suggest that anginal syndromes that are refractory to medical treatment can be caused by unstable pathologic processes in the intima. Ulceration of plaques may increase the frequency and severity of effort angina, and the subsequent development of partially occlusive thrombi may cause unstable rest angina.

Real-time radionuclide cineangiography in the noninvasive evaluation of global and regional left ventricular function at rest and during exercise in patients with coronary-artery disease

Although coronary angiography defines regions of potential ischemia in patients with coronary-artery disease, accurate assessment of the presence and functional importance of ischemia requires appraisal of regional and global left ventricular function during stress. To perform such assessment, we developed a noninvasive real-time radionuclide cineangiographic procedure permitting continuous monitoring and analysis of left ventricular function during exercise. In 11 patients with coronary disease who had normal regional and global ventricular function at rest, new regions of dysfunction developed during exercise (P less than 0.001), and in 10, global ejection fraction dropped 7 to 47 per cent. Fourteen age-matched normal subjects were studied; during exercise none had regional dysfunction, and each increased global ejection fraction (average increase, 23 +/- 3 per cent [+/-S.E.], P less than 0.001 as compared with patients with coronary disease). Radionuclide cineangiography during exercise permits accurate assessment of the presence and functional severity of ischemic heart disease.

Predictors of outcome in patients with acute coronary syndromes without persistent ST-segment elevation. Results from an international trial of 9461 patients. The PURSUIT Investigators

BACKGROUND

Appropriate treatment policies should include an accurate estimate of a patient's baseline risk. Risk modeling to date has been underutilized in patients with acute coronary syndromes without persistent ST-segment elevation.

METHODS AND RESULTS

We analyzed the relation between baseline characteristics and the 30-day incidence of death and the composite of death or myocardial (re)infarction in 9461 patients with acute coronary syndromes without persistent ST-segment elevation enrolled in the PURSUIT trial [Platelet glycoprotein IIb/IIIa in Unstable angina: Receptor Suppression Using Integrilin (eptifibatide) Therapy]. Variables examined included demographics, history, hemodynamic condition, and symptom duration. Risk models were created with multivariable logistic regression and validated by bootstrapping techniques. There was a 3.6% mortality rate and 11.4% infarction rate by 30 days. More than 20 significant predictors for mortality and for the composite end point were identified. The most important baseline determinants of death were age (adjusted chi(2)=95), heart rate (chi(2)=32), systolic blood pressure (chi(2)=20), ST-segment depression (chi(2)=20), signs of heart failure (chi(2)=18), and cardiac enzymes (chi(2)=15). Determinants of mortality were generally also predictive of death or myocardial (re)infarction. Differences were observed, however, in the relative prognostic importance of predictive variables for mortality alone or the composite end point; for example, sex was a more important determinant of the composite end point (chi(2)=21) than of death alone (chi(2)=10). The accuracy of the prediction of the composite end point was less than that of mortality (C-index 0.67 versus 0.81).

CONCLUSIONS

The occurrence of adverse events after presentation with acute coronary syndromes is affected by multiple factors. These factors should be considered in the clinical decision-making process.

Silent ischemia as a marker for early unfavorable outcomes in patients with unstable angina

We examined the prevalence and prognostic importance of silent myocardial ischemia detected by continuous electrocardiographic monitoring in 70 patients with unstable angina. All the patients received intensive medical treatment with nitrates, beta-blockers, and calcium-channel blockers. Continuous electrocardiographic recordings were made during the first two days in the coronary care unit to quantify the frequency and duration of asymptomatic ischemic episodes, defined as a transient ST-segment shift of 1 mm or more. Thirty-seven patients (Group 1) had at least one episode of silent ischemia, and the other 33 patients had no silent ischemia (Group 2). Over the subsequent month, myocardial infarction occurred in 6 patients in Group 1 and in only 1 in Group 2 (P less than 0.01); bypass surgery or angioplasty was required for recurrent symptomatic angina in 10 patients in Group 1 and only 3 in Group 2 (P = 0.02). Survival-curve analysis demonstrated that silent ischemia was associated with these outcomes (P less than 0.002), and multivariate analysis showed that silent ischemia was the best predictor of these outcomes among the 15 variables tested (P less than 0.002). Patients in Group 1 with 60 minutes or more of silent ischemia per 24 hours had a worse prognosis than those with under 60 minutes per 24 hours (P = 0.04). Silent ischemia occurred in more than 50 percent of our patients with unstable angina, despite intensive medical therapy, and it identified a subset who were at high risk for early unfavorable outcomes.

Elevated levels of oxidized low density lipoprotein show a positive relationship with the severity of acute coronary syndromes

BACKGROUND

There is accumulating data that acute coronary syndromes relate to recent onset activation of inflammation affecting atherosclerotic plaques. Increased blood levels of oxidized low density lipoprotein (ox-LDL) could play a role in these circumstances.

METHODS AND RESULTS

Ox-LDL levels were measured in 135 patients with acute myocardial infarction (AMI; n=45), unstable angina pectoris (UAP; n=45), and stable angina pectoris (SAP; n=45) and in 46 control subjects using a sandwich ELISA method. In addition, 33 atherectomy specimens obtained from a different cohort of patients with SAP (n=10) and UAP (n=23) were studied immunohistochemically for ox-LDL. In AMI patients, ox-LDL levels were significantly higher than in patients with UAP (P<0.0005) or SAP (P<0.0001) or in controls (P<0.0001) (AMI, 1.95+/-1.42 ng/5 microgram LDL protein; UAP, 1.19+/-0.74 ng/5 microgram LDL protein; SAP, 0.89+/-0.48 ng/5 microgram LDL protein; control, 0.58+/-0.23 ng/5 microgram LDL protein). Serum levels of total, HDL, and LDL cholesterol did not differ among these patient groups. In the atherectomy specimens, the surface area containing ox-LDL-positive macrophages was significantly higher in patients with UAP than in those with SAP (P<0.0001).

CONCLUSIONS

This study demonstrates that ox-LDL levels show a significant positive correlation with the severity of acute coronary syndromes and that the more severe lesions also contain a significantly higher percentage of ox-LDL-positive macrophages. These observations suggest that increased levels of ox-LDL relate to plaque instability in human coronary atherosclerotic lesions.

Transient asymptomatic S-T segment depression during daily activity

The significance of asymptomatic episodes of ischemic type S-T segment depression was studied in 20 patients with coronary heart disease. Continuous 10 hour electrocardiographic recordings accompanied by detailed daily diaries of activity and symptoms were obtained periodically during a mean time of 16 months. All patients had ischemic type S-T depression associated with angina pectoris during treadmill exercise. Measurements of heart rate, S-T depression and exercise level at the onset of angina obtained during repeated controlled exercise tests at the start of each study period were compared with the measurements recorded during daily activity. After 2,826 hours of recording, 411 transient epidsodes of ischemic type S-T depression were noted during usual daily activity. Only 101 (25 percent) of these episodes were associated with angina. The remaining episodes were unrelated to other symptoms or to posture. All occurred at heart rates significantly lower than those observed at the onset of angina during exercise testing. Of these episodes of asymptomatic S-T depression, 72 percent occurred only at rest or during very light activity such as slow walking or sitting. Nitroglycerin administered hourly significantly reduced the frequency of these episodes, thus supporting the concept that they represent painless ischemia. Because the episodes of asymptomatic ischemic type S-T depression occurred more frequently than angina during usual daily activity and were evident at heart rates and activity levels well below those expected to evoke ischemia, they may be caused by factors other than those that cause angina.

Prognostic value of exercise testing soon after myocardial infarction

The prognostic value of a limited treadmill exercises test performed one day before hospital discharge after acute myocardial infarction was studied in 210 consecutive patients who had no over heart failure and had been free of chest pain for at least four days. No complications occurred. During a one-year follow-up period 28 of 43 patients (65 per cent) who had chest pain during the test reported angina, as compared with 60 of 167 (36 per cent) who had no chest pain during test (P less than 0.001). The one-year mortality rates were 2.1 per cent (three of 146) in patients without changes in the S-T segment during exercise and 27 per cent (17 of 64) in those with depression of the S-T segment (P less than 0.001). Sudden death occurred in one of 146 (0.7 per cent) patients who showed no change in the S-T segment and in 10 of 64 (16 per cent) with depression of the segment (P less than 0.001). Thus, a limited treadmill exercise test performed before hospital discharge after acute myocardial infarction is safe and can predict mortality in the subsequent year.

A computer protocol to predict myocardial infarction in emergency department patients with chest pain

To achieve more appropriate triage to the coronary care unit of patients presenting with acute chest pain, we used clinical data on 1379 patients at two hospitals to construct a simple computer protocol to predict the presence of myocardial infarction. When we tested this protocol prospectively in 4770 patients at two university hospitals and four community hospitals, the computer-derived protocol had a significantly higher specificity (74 vs. 71 percent) in predicting the absence of infarction than physicians deciding whether to admit patients to the coronary care unit, and it had a similar sensitivity in detecting the presence of infarction (88.0 vs. 87.8 percent). Decisions based solely on the computer protocol would have reduced the admission of patients without infarction to the coronary care unit by 11.5 percent without adversely affecting the admission of patients in whom emergent complications developed that required intensive care. Although this protocol should not be used to override careful clinical judgment in individual cases, the computer protocol for the most part yields accurate estimates of the probability of myocardial infarction. Decisions about admission to the coronary care unit based on the protocol would have been as effective as those actually made by the unaided physicians who cared for the patients, and less costly. Whether physicians who are aided by the protocol perform better than unaided physicians cannot be determined without further study.

Interleukin-18 is a strong predictor of cardiovascular death in stable and unstable angina

BACKGROUND

Interleukin (IL)-18 plays a central role in orchestrating the cytokine cascade and accelerates atherosclerosis and plaque vulnerability in animal models. However, epidemiological data evaluating the role of IL-18 levels in atherosclerosis are lacking.

METHODS AND RESULTS

In a prospective study of 1229 patients with documented coronary artery disease, we measured baseline serum concentrations of IL-18 and other markers of inflammation. During the follow-up period (median, 3.9 years), 95 patients died of cardiovascular causes. Median serum concentrations of IL-18 were significantly higher among patients who had a fatal cardiovascular event than among those who did not (68.4 versus 58.7 pg/mL; P<0.0001). The hazard risk ratio of future cardiovascular death increased with increasing quartiles of IL-18 (hazard risk ratio, 1.46; 95% CI 1.21 to 1.76; P for trend <0.0001). After adjustment for most potential confounders, including the strong predictor ejection fraction as well as the inflammatory variables IL-6, high-sensitive C-reactive protein, and fibrinogen, this relation remained almost unchanged, such that patients within the highest quartile of IL-18 had a 3.3-fold increase in hazard risk compared with those in the first quartile (95% CI, 1.3 to 8.4, P=0.01). This relation was observed in patients with stable angina and patients with unstable angina at baseline.

CONCLUSIONS

Serum IL-18 level was identified as a strong independent predictor of death from cardiovascular causes in patients with coronary artery disease regardless of the clinical status at admission. This result strongly supports recent experimental evidence of IL-18-mediated inflammation leading to acceleration and vulnerability of atherosclerotic plaques.

Endothelial progenitor cell capture by stents coated with antibody against CD34: the HEALING-FIM (Healthy Endothelial Accelerated Lining Inhibits Neointimal Growth-First In Man) Registry

OBJECTIVES

This study was designed to evaluate whether rapid endothelialization of stainless steel stents with a functional endothelium prevents stent thrombosis and reduces the restenotic process.

BACKGROUND

A "pro-healing" approach for prevention of post-stenting restenosis is theoretically favored over the use of cytotoxic or cytostatic local pharmacologic therapies. It is believed that the central role of the vascular endothelium is to maintain quiescence of the underlying media and adventitia.

METHODS

Sixteen patients with de novo coronary artery disease were successfully treated with implantation of endothelial progenitor cell (EPC) capture stents.

RESULTS

Complete procedural and angiographic success was achieved in all 16 patients. The nine-month composite major adverse cardiac and cerebrovascular events (MACCE) rate was 6.3% as a result of a symptom-driven target vessel revascularization in a single patient. There were no other MACCE despite only one month of clopidogrel treatment. At six-month follow-up, mean angiographic late luminal loss was 0.63 +/- 0.52 mm, and percent stent volume obstruction by intravascular ultrasound analysis was 27.2 +/- 20.9%.

CONCLUSIONS

This first human clinical investigation of this technology demonstrates that the EPC capture coronary stent is safe and feasible for the treatment of de novo coronary artery disease. Further developments in this technology are warranted to evaluate the efficacy of this device for the treatment of coronary artery disease.

Differentiation of transiently ischemic from infarcted myocardium by serial imaging after a single dose of thallium-201

Myocardial 201Tl uptake and regional blood flow by the microsphere technique were determined in anesthetized dogs undergoing either 20 min of coronary occlusion and 100 min of reperfusion (N = 10) or 120 min of occlusion (N = 4). In both groups, 201Tl was injected intravenously after 10 min of occlusion. In transiently occluded dogs, regional flow at the time of 201Tl administration was reduced to 8 +/- 3% of normal flow in endocardial layers of the central ischemic zone. After 100 min of reperfusion, flow values were not significantly different from normal. 201Tl activity after reperfusion rose to 56 +/- 5% of normal, demonstrating that redistribution of the radionuclide occurred during the reflow period. In animals with persistent occlusion, there was a significant relationship between 201Tl uptake and flow (r = 0.95) and no evidence of redistribution of 201Tl during the two hour occlusion period. In another five dogs receiving 201Tl, serial gamma camera images obtained during reperfusion showed increasing uptake of the tracer in apical defects which returned to normal by 4 hours of reflow. Thirteen patients with stable angina received 2 mCi of 201Tl intravenously at peak exercise, and multiple gamma camera images obtained serially. All demonstrated zones of diminished 201Tl uptake 10 min after exercise. Defects which partially or completely disappeared within 1-6 hours postexercise corresponded to areas supplied by coronary arteries with significant stenoses. Persistent defects were present in regions of old myocardial infarction. Six additional patients with acute myocardial infarction demonstrated 201Tl myocardial defects which showed no significant change over 6 hours. Thus, redistribution of 201Tl into ischemic myocardium was demonstrated during transient coronary occlusion in dogs and after exercise stress in man. Sequential imaging after a single dose of 201Tl at the time of exercise may provide a means for distinguishing between transient perfusion abnormalities or ischemia and myocardial infarction of scar.

Selective cine coronary arteriography. Correlation with clinical findings in 1,000 patients

The clinical records of 1,000 patients who had adequate selective cine coronary arteriography were reviewed. The clinical diagnoses were made by a physician who had no knowledge of the arteriographic findings. Correlation of the clinical diagnoses with the arteriographic findings was made subsequently.

Symptomatic coronary disease was accompanied by arteriographic evidence of significant obstruction of major coronary arteries in most instances. A close correlation existed between the clinical diagnosis of angina pectoris without rest pain and significant arterial obstruction (95%). A similar correlation was found between QRS evidence of myocardial infarction and severe arterial obstruction (99%). The demonstrated arterial obstruction in patients who had angina pectoris almost always was severe and usually almost total or total in one or more major vessels. In myocardial infarction the demonstrated obstruction was always severe and generally almost total or total.

The correlation between clinical and arteriographic findings was moderately close in patients who had angina with symptoms at rest. The correlation between the arteriographic findings and less characteristic clinical syndromes (rest pain only, 79%, coronary failure, 78%, and especially atypical angina pectoris, 65%) was not so close. In congestive failure secondary to coronary disease, arterial obstruction was extensive unless ventricular aneurysm, mitral insufficiency, arrhythmia, arterial hypotension, or some other complication was present. Most patients thought to have noncoronary symptoms had no significant obstructive lesions.

In 37% of the entire group of patients, almost all of whom had been suspected of having coronary disease by some physicians, no significant arteriographic obstruction was demonstrated; in 27% the arteriograms were normal.

Diagnoses, based on appraisal of the clinical records without knowledge of the arteriographic findings, yielded 83% correlation with abnormal arteriographic findings in 700 patients thought to have coronary disease.

High levels of circulating endothelial microparticles in patients with acute coronary syndromes

BACKGROUND

Endothelial injury plays a critical role in coronary artery disease (CAD), but the assessment of this injury has been problematical. Recently, it has been shown in vitro that endothelial cells (ECs) release endothelial microparticles (EMPs) on activation or apoptosis and that an assay of EMPs can provide useful information on EC status in patients with thrombotic disorders. This study is aimed at assessing possible correlations between EMPs, which are markers of endothelial injury, and clinical subgroups of patients with CAD.

METHODS

A prospective, case-controlled study was conducted on 84 patients with CAD and 42 control subjects to investigate EMP profiles. Included were 64 patients with acute coronary syndromes ([ACS], 38 with myocardial infarction [MI] and 26 with unstable angina [UA]) and 20 patients with stable angina (SA). EMPs in platelet-poor plasma were measured flow cytometrically with combinations of fluorescent antibodies (anti-CD31, -51, -42), allowing distinction of EMPs from platelet microparticles (PMPs). Clinical subgroups of patients were correlated with EMP and PMP levels in blood.

RESULTS

Two species of EMPs (CD31+ and CD51+) were evaluated. Both were significantly higher in patients with CAD than in control subjects. CD31+ EMP was higher in ACS than SA. Among patients with first MI, CD31+ EMP was higher in patients with MI than in patients with UA and was significantly higher than in patients with recurring MI. CD51+ EMP did not discriminate ACS from SA. A simultaneous assay of PMP showed correlation between EMPs and PMPs. However, PMPs did not discriminate patients with SA from control subjects.

CONCLUSIONS

EMP assay appears promising for assessing EC injury in CAD.

Prinzmetal's variant form of angina as a manifestation of alpha-adrenergic receptor-mediated coronary artery spasm: documentation by coronary arteriography

In four patients with Prinzmetal's variant form of angina, the attack was induced by the combined administration of epinephrine (0.4 to 0.5 mg, given subcutaneously at 7:30 to 8:00 A.M.) and propranolol (40 mg. given orally at 5:00 A.M.). Selective coronary cinearteriography was done before, during, and after the attack with constant monitoring of the ECG and blood pressure. Severe spasm of the right coronary artery occurred at the proximal portion in association with ST-segment elevation in Lead III during the attack and disappeared with the subsidence of the attack in all of them. These results strongly suggest that severe spasm of a large coronary artery mediated by alpha-adrenergic receptors is responsible for the attack of Prinzmetal's variant form of angina.

Exercise stress testing. Correlations among history of angina, ST-segment response and prevalence of coronary-artery disease in the Coronary Artery Surgery Study (CASS)

To determine to what extent the diagnostic accuracy of stress testing is influenced by the prevalence of coronary-artery disease, we correlated the description of chest pain, the result of stress testing and the results of coronary arteriography in 1465 men and 580 women from a multicentered clinical trial. The pre-test risk (prevalence of coronary-artery disease) varied from 7 to 87 per cent, depending on sex and classification of chest pain. A positive stress test increased the pre-test risk by only 6 to 20 per cent, whereas a negative test decreased the risk by only 2 to 28 per cent. Aothough the percentage of false-positive results differed between men and women (12 +/- 1 per cent versus 53 +/- 3 per cent P less than 0.001), this difference was not seen in a subgroup matched for prevalence of coronary-artery disease. We conclude that the ability of stress testing to predict coronary-artery disease is limited in a heterogeneous population in which the prevalence of disease can be estimated through classification of chest pain and the sex of the patient.

Transient ST-segment depression as a marker of myocardial ischemia during daily life

Patients with angina and coronary artery disease (CAD) have many episodes of transient ST-segment depression during ordinary daily life, and these are often asymptomatic. To investigate this signal as a marker of myocardial ischemia, 30 patients with chronic stable angina and CAD underwent positron tomography, recording the regional myocardial uptake of rubidium-82, pain and ST-segment changes before, during and after 59 technically satisfactory exercise tests, 35 cold pressor tests and 22 episodes of unprovoked ST depression. Exercise resulted in 53 episodes of ST depression with angina and in 5 episodes without pain. After cold pressor tests, there were 3 episodes of ST depression and pain and 12 of painless ST depression. Only 9 episodes of unprovoked ST depression were accompanied by pain. Tomography showed independent evidence of ischemia in 63 (97%) of the total 65 episodes of ST depression with angina and in all 30 episodes of painless ST depression. In each patient perfusion defects occurred in the same myocardial segment during painful and painless ST depression and responses were significantly different from those in 16 normal subjects studied in the same way. These findings support the use of transient ST depression in continuous monitoring to assess the activity of CAD, but only in patients with typical angina pectoris, ST depression during exercise and proved CAD. They strengthen the evidence derived from ambulatory monitoring for a wider picture of the disease than is generally appreciated, with more frequent episodes of silent myocardial ischemia than of angina pectoris.

Value of the history and physical in identifying patients at increased risk for coronary artery disease

OBJECTIVE

To determine whether information from the physician's initial evaluation of patients with suspected coronary artery disease predicts coronary anatomy at catheterization and 3-year survival.

DESIGN

Prospective validation of regression model estimates in an outpatient cohort.

SETTING

University medical center.

PATIENTS

A total of 1030 consecutive outpatients referred for noninvasive testing for suspected coronary artery disease; 168 of these patients subsequently underwent catheterization within 90 days.

MEASUREMENTS

Information from the initial history, physical examination, electrocardiogram, and chest radiograph was used to predict coronary anatomy (the likelihood of any significant coronary disease, severe disease [left main or three-vessel], and significant left main disease) among 168 catheterized patients and to estimate 3-year survival among all patients. These estimates were compared with those based on treadmill testing. Cardiovascular testing charges were calculated for all patients.

RESULTS

Predicted coronary anatomy and survival closely corresponded to actual findings. Compared with the treadmill exercise test, initial evaluation was slightly better able to distinguish patients with or without any coronary disease and was similar in the ability to identify patients at increased risk for dying or with anatomically severe disease. Based on arbitrary definitions, 37% to 66% of patients were at low risk and responsible for 31% to 56% of the charges for cardiovascular testing.

CONCLUSIONS

The physician's initial evaluation, despite the subjective nature of much of the information gathered, can be used to identify patients likely to benefit from further testing. The development of strategies for cost-conscious quality care must begin with the history, physical examination, and simple laboratory testing.