Using physiologic and pharmacologic stress testing in the evaluation of coronary artery disease

Evaluating and treating coronary artery disease (CAD), the leading cause of death in the United States, are priorities for primary care practitioners. Stress testing is a noninvasive, cost-effective technique to help diagnose CAD and evaluate its extent. The test can also be used to clarify the etiology of chest pain, evaluate a medical regimen, identify arrhythmias, risk-stratify patients preoperatively, and determine exercise tolerance. Myocardial perfusion imaging and echocardiography can increase the test's sensitivity and specificity. Pharmacologic testing is available to evaluate patients who are unable to exercise adequately. Test selection is based on the patient's ability to exercise, concurrent illnesses (for example, reactive airway disease), and desired findings. The evaluation of results should be based on history and the pretest probability of cardiovascular disease. A cardiologist should evaluate any results that fall to correlate with the patient's presentation or pretest likelihood of disease for possible coronary angiography.     

Musculoskeletal chest pain in patients with "angina": a prospective study

We prospectively evaluated 62 adults referred for coronary arteriography, using a systematic physical examination protocol to identify musculoskeletal sources of chest pain. In seven patients (11%) the chest pain was reproduced on physical examination; six of them ultimately had a diagnosis of nonanginal chest pain made by their cardiologist, based on history and data from noninvasive and coronary arteriographic studies. Five had normal coronary arteriograms. These patients described their pain in terms often associated with true angina. Musculoskeletal tenderness that did not reproduce the pain was common and was unrelated to coronary artery disease. Demonstration of musculoskeletal tenderness that reproduces chest pain, when combined with noninvasive findings suggesting low probability of coronary artery disease, may be useful in decreasing the incidence of unnecessary invasive cardiac evaluation, and appropriately directing initial therapy.     

The predictive value of chronic kidney disease for assessing cardiovascular events under consideration of pretest probability for coronary artery disease in patients who underwent stress myocardial perfusion imaging

Pretest probability of coronary artery disease (CAD) facilitates diagnosis and risk stratification of CAD. Stress myocardial perfusion imaging (MPI) and chronic kidney disease (CKD) are established major predictors of cardiovascular events. However, the role of CKD to assess pretest probability of CAD has been unclear. This study evaluates the role of CKD to assess the predictive value of cardiovascular events under consideration of pretest probability in patients who underwent stress MPI. Patients with no history of CAD underwent stress MPI (n = 310; male = 166; age = 70; CKD = 111; low/intermediate/high pretest probability = 17/194/99) and were followed for 24 months. Cardiovascular events included cardiac death and nonfatal acute coronary syndrome. Cardiovascular events occurred in 15 of the 310 patients (4.8 %), but not in those with low pretest probability which included 2 CKD patients. In patients with intermediate to high pretest probability (n = 293), multivariate Cox regression analysis identified only CKD [hazard ratio (HR) = 4.88; P = 0.022) and summed stress score of stress MPI (HR = 1.50; P < 0.001) as independent and significant predictors of cardiovascular events. Cardiovascular events were not observed in patients with low pretest probability. In patients with intermediate to high pretest probability, CKD and stress MPI are independent predictors of cardiovascular events considering the pretest probability of CAD in patients with no history of CAD. In assessing pretest probability of CAD, CKD might be an important factor for assessing future cardiovascular prognosis.     

Radiographic evaluation of the patient with chest pain of suspected myocardial origin

The evaluation of the patient with suspected angina pectoris is discussed and an approach presented which makes use of radiologic tests in conjunction with exercise testing to quickly and efficiently determine the likelihood and severity of coronary artery disease. The relative merits and limitations of chest radiography, cardiac fluoroscopy, nuclear medicine, and coronary arteriography are discussed.     

Early exercise thallium-201 single photon emission computed tomography in unstable angina: a prospective study

Summary. To evaluate the safety and diagnostic value of early symptom-limited exercise electrocardiography (ECG) and exercise thallium-201 single photon emission computed tomography (SPECT) in unstable angina (UA), 39 patients were studied prospectively soon after stabilization on medical treatment. No patient had a history of myocardial infarction (MI) or revascularization and patients with left bundle branch block were excluded. Exercise ECG and exercise thallium-201 SPECT were performed 8 plusmn; 4 days and 11 plusmn; 6 days respectively after admission to hospital. Seventeen out of 39 patients (44%) had positive exercise ECGs and 22 (56%) negative or inconclusive ones. Exercise thallium-201 SPECT was positive in 26 patients (67%) and negative in 13 patients (33%). Thirty-one patients underwent coronary arteriography and 24 of them proved to have significant coronary artery disease (CAD). The sensitivity, specificity and positive predictive value of exercise ECG in detecting CAD are 62%, 86%, and 94% respectively while the corresponding results are 96%, 100%, and 100% for exercise thallium-201 SPECT. Therefore, it is concluded that the early symptom-limited exercise test is safe in medically stabilized patients with UA. Early exercise thallium-201 SPECT is highly sensitive and predictive of the presence of significant CAD among patients in the early recovery phase of UA and can be used in selecting this group of patients for coronary angiography and other therapeutic strategies.     

Diagnostic and prognostic value of exercise electrocardiography for coronary artery disease

A positive exercise ECG with greater than or equal to 1.0 mm ischemic ST-segment depression, limited exercise duration, persistence of ischemic ST-segment depression past 8 minutes in the recovery period, and exertional hypotension is associated with increasing severity and extent of CAD. The sensitivity and specificity of the exercise ECG are not dependent on the prevalence of CAD in the population tested. The positive and negative predictive values of the exercise ECG are both dependent on the prevalence of CAD in the population tested. Exercise-induced ST-segment elevation greater than or equal to 1.0 mm is associated with severe myocardial ischemia, left ventricular aneurysm, left ventricular wall motion abnormalities, and coronary artery spasm in patients with variant angina. Ischemic ST-segment depression greater than or equal to 1.0 mm, exercise duration, maximal exercise heart rate, and blood pressure response to exercise are correlated with new coronary events in patients with documented CAD. Low-level exercise tests within 3 weeks of uncomplicated MI can identify patients at high risk for new cardiac events. Early post-MI patients with exercise-induced ischemic ST-segment depression greater than or equal to 1.0 mm, exercise-induced angina, an inadequate blood pressure response to exercise, or limited exercise duration during a low-level exercise test should undergo coronary angiography and be considered for possible coronary artery surgery or angioplasty. Exercise testing will also help in the medical treatment of patients with exercise-induced angina or malignant ventricular arrhythmias. An exercise test performed 6 months after MI also provides prognostic information not available from clinical evaluation.(ABSTRACT TRUNCATED AT 250 WORDS)     

Analysis of referral diagnoses of patients with normal coronary angiogram]

BACKGROUND AND AIMS: Angiography permits an evaluation of the morphology of the coronary artery, stratification of risk and optimal therapeutic management in patients with suspected coronary artery disease (CAD). The sophisticated apparatus, cost and invasiveness of the procedure necessitate well-considered application of this method. In spite of an exact documentation of the patient's medical history and careful establishment of the indication, the results of angiography are often normal. Therefore, it appears important to analyse the referral diagnoses in patients with normal coronary angiograms. PATIENTS AND METHODS: We studied 1000 consecutive patients (625 men, 375 women, mean age 63.1 years) who underwent coronary angiography at our institution from January to May 1998. All patients were included in the retrospective analysis of the referral diagnoses. RESULTS: 875 patients (554 men, 321 women) were referred due to suspected CAD; 173 of these had normal angiographic findings (20%; 73 men, 100 women; mean age 58.4 years). The referral diagnoses were as follows: unstable angina in 62 patients (36%), stable angina in 40 patients (23%), chest pain and pathological findings of non-invasive testing in 32 patients (19%), atypical chest pain in 25 patients (14%), previous myocardial infarction and multiple risk factors in 7 patients each (4% each). Gender-related differences were remarkable. Only 73 of the 554 referred men (13%) had normal angiographic findings, whereas in women the rate of normal results was more than twofold higher, i.e. 100 of the 321 referred women (31%) had normal angiographic findings (p < 0.01). CONCLUSIONS: Among 875 patients referred to our catheter laboratory for coronary angiography due to suspected CAD, normal angiographic results were documented in 20%. The high frequency of the referral diagnosis 'unstable angina' and 'pathological result of noninvasive testing' was as remarkable as the high proportion of women among patients with normal findings.     

Bioimpedance-derived differences in cardiac physiology during exercise stress testing in low-risk chest pain patients

BACKGROUND: Little has been written about the utility of thoracic electrical bioimpedance (TEB)-derived cardiac physiologic variables in evaluating patients with low-risk chest pain syndromes. Noninvasive bioimpedance can monitor cardiac physiology while a patient is performing an exercise stress test. In addition, the demographics of patients with chest pain, the incidence of coronary artery disease (CAD), and the methods used for evaluation have well-documented sex differences. OBJECTIVE: The objectives are to show that there are different cardiac physiologic responses to exercise stress test in Chest Pain Evaluation Unit patients with and without true CAD that could be used to stratify patients and that there is a sex difference in TEB results. METHODS: Patients 18 to 65 years of age with low-risk chest pain were eligible. Patients were attached to the TEB throughout the exercise stress test procedure. Heart rate (HR) was monitored. Primary dependent variables were TEB-measured cardiac output (CO, L/min) and stroke volume (SV, ml) at peak exercise. Secondary variables were TEB-measured ejection fraction (%), end-diastolic volume (EDV, ml), ventricular ejection time (ms), and thoracic fluid index (omega) at peak exercise. Outcome variables were either proved CAD or patient sex. CAD was proved by angiography, stress scintigraphy, or stress echocardiogram. Results were compared using a Student's t test assuming equal variances, with significance considered at a P < 0.05, and 95% confidence intervals were calculated for significant results. RESULTS: Nine patients had proved CAD, 82 patients did not. Forty-three women and 48 men were included in the study. At peak exercise, patients with CAD had a significantly smaller increase in EDV than patients without CAD (32.8 +/- 59.5 ml versus 89.3 +/- 101.8 ml) without a significant change in CO, SV, or HR. At peak exercise, women had a significantly smaller increase in CO and SV without a significant change in HR. In addition, women had a significantly smaller increase in EDV. CONCLUSION: When compared with patients without CAD, patients with CAD have a significantly smaller increase in EDV and a trend toward the same effect in CO and SV. Women have significantly smaller increases CO, SV, and EDV compared with men. Because there were no differences in HR, using HR as the sole end point would miss these differences. TEB is a practical means of measuring these variables.     

Tests for ischaemia and left ventricular function in young patients with effort-induced chest pain

The type of angina pectoris was determined in 47 women and 27 men aged 40 or less who then underwent quantitative left cineventriculography, coronary arteriography and atrial pacing test with determination of lactate concentrations from arterial and coronary sinus blood samples. The 29/74 patients with atypical angina and no narrowings on coronary arteriography (Group I) gave no pathological atrial pacing tests but 9 had pathological lactate tests. Group II consisted of 27/74 patients with typical angina but normal coronary arteriography. In these the atrial pacing test was pathological in 20 and the lactate test in 11. Coronary narrowings of 50% or more were found in 18/74 patients (Group III), who all had pathological pacing tests but only 9 pathological lactate tests. No statistical differences could be elicited between diagnostic groups in the quantitative evaluation of left ventricular function and it could be regarded as normal in 42/74 patients. The left ventricular mass index exceeded the control level in 6 patients in Group I and in 10 patients in Group II who all had a net lactate production upon pacing. The end-diastolic volume index was above control level in 11 patients in Group II, in whom the ST depression in pacing test was the only finding indicating ischemia. The hoop stress values exceeded the control level in both of these subgroups. In Group III 7 patients had a high left ventricular mass index and 4 a billowing mitral leaflet. The changes observed suggest disturbed functioning of left ventricle.     

Differences in clinical presentation of deep vein thrombosis in men and women

Summary. Background: As assessment of clinical pretest probability is the first step in the diagnostic evaluation of deep vein thrombosis (DVT), it is important to know if the clinical features of DVT are the same in men and women. Objectives: To compare the prevalence and clinical characteristics of DVT, and the accuracy of clinical pretest probability assessment, between men and women with suspected DVT. Methods: A retrospective analysis of individual patient data from three prospective studies by our group that evaluated diagnostic tests for a suspected first episode of DVT. Clinical characteristics, clinical pretest probability for DVT, and prevalence and extent of DVT was assessed in a total of 1838 outpatients. Results: The overall prevalence of DVT was higher in men than in women (14.4% vs. 9.4%) (P = 0.001). The prevalence of DVT was higher in men than in women who were categorized as having a clinical pretest probability that was low (6.9% vs. 3.5%; P = 0.025) or moderate (16.9% vs. 8.7%; P = 0.04), but similar in patients in the high category (40.2% vs. 44.0%; P = 0.6). In patients diagnosed with DVT, swelling of the entire leg occurred more often (41.5% vs. 15.7%; P < 0.001), and thrombosis was more extensive (involvement of both popliteal and common femoral veins in 47.9% vs. 21.6%), in women than in men. Conclusions: In outpatients with suspected DVT, the overall prevalence of thrombosis and the prevalence of thrombosis in those with a low or a moderate clinical pretest probability were higher in men than in women.     

Diagnosis and screening of coronary artery disease

Diagnostic testing for CAD is aided by the calculation of the pretest probability using either the Diamond-Forrester score or the Morise score. Patients who have a low risk of CAD should not undergo testing. Exercise ECG testing should be reserved for patients who have pretest probabilities lower than 20%, because a negative test does not adequately reduce the posttest probability of significant CAD. For patients who are at intermediate risk, either nuclear perfusion imaging or stress echocardiography is an acceptable choice depending on local availability and practice. Due to its low specificity, CAC scoring is currently limited in its usefulness for the diagnosis of CAD in symptomatic patients. Currently, screening for CAD among patients at low risk should not extend beyond screening for traditional risk factors. Physicians should use the Framingham Risk Score to stratify patients into levels of 10-year risk for cardiac events. Due to its high rate of false positive tests and low sensitivity, exercise ECG is of limited value in screening. Among patients with higher levels of risk, in whom further risk stratification would be of use in making decisions about risk factor management, measurement of CAC either with EBCT or multidetector row CT scanning is a promising option, but more research is required before its use should become widespread. Measures of endothelial function are in development but lack data to support their widespread use currently.     

潘生丁超声心动图试验诊断冠心病

选用了确诊的２５例冠心病进行潘生丁超声心动图试验（ＤＥＴ），以新出现节段性室壁运动异常（ＲＷＭＡ）为阳性指标。结果阳性率为６４％。对照组１６例均呈阴性。２例心绞痛患者ＰＴＣＡ前均可见与狭窄血管供血区相当的ＲＷＭＡ，术后５天复查均转为阴性。共２４例受试者出现副作用。大多数较轻，不需治疗自行缓解。但有１例患者诱发广泛心肌缺血并出现室颤，抢救无效死亡。本试验操作简便，特异性强，具有一定的敏感性，可用于不能进行运动试验的患者。但本试验亦非十分安全，故选择试验应从严掌握，试验过程需严密观察及备有急救措施。     

Comparison of peak and postexercise treadmill echocardiography with the use of continuous harmonic imaging acquisition.

OBJECTIVES: We sought to compare the feasibility and accuracy of peak and postexercise treadmill echocardiography with the use of continuous harmonic imaging capture. BACKGROUND: Previous work has demonstrated the superiority of peak exercise echocardiography (EE) as compared with post-EE for the diagnosis of coronary artery disease (CAD). However, most of these studies used fundamental imaging and view-per-view acquisition systems. Technical advantages in stress echocardiography include harmonic imaging and continuous imaging capture. METHODS: The study group included 650 patients (423 men; 60 +/- 12 years) who were submitted to peak and postexercise treadmill echocardiography. RESULTS: Postexercise images were acquired within 55 seconds after exercise (28 +/- 10). The number of segments visualized in each view were similar at peak and post-EE except for the parasternal short-axis view, which was better qualified at postexercise. For analysis of diagnostic capability we included 312 patients: 195 were included on the basis of having had an EE and a coronary angiography, whereas 117 patients with pretest probability of CAD < 10% who had atypical chest pain or were asymptomatic were also included and considered as having no CAD. CAD (>/=50% stenosis) was confirmed in 159 patients. Positive EE was defined as ischemia or necrosis. Sensitivity for CAD was higher with peak imaging (92% vs 77%, P <.001), with similar specificity (78% vs 87%, P = not significant) and accuracy (85% vs 82%, P = not significant). CONCLUSION: Peak treadmill EE is technically feasible and has higher sensitivity for CAD than posttreadmill EE. Therefore, in the clinical setting, peak EE should be performed for diagnostic purposes.     

Adenosine echocardiography — an alternative to dynamic stress echocardiography

Dynamic exercise echocardiography is sensitive and specific in detection and evaluation of coronary artery disease. Frequently, however, patients cannot achieve maximum exercise because of various factors. The aims of this study were to compare usefulness of adenosine infusion and dynamic exercise to induce myocardial ischemia detected with 2-D echocardiography and standard electrocardiography; to determine the sensitivity of the adenosine echo test; and to evaluate the safety and tolerability of adenosine infusion. In 31 men with clinical diagnosis of stable angina pectoris, myocardial ischemia was induced by: a) symptom-limited exercise test on a bicycle, and b) intravenous adenosine infusion. The two tests were performed with an average interval of 24 hours. Coronary angiography was performed in 29 of 31 patients and significant coronary artery disease (diameter narrowing >50%) was documented in 26 of these (12 single, 6 two- and 8 three-vessel disease). The criterion for echo positivity was a transient impairment of contraction as compared to the baseline examination in any of 10 segments, with an increase of left ventricular score index of 0.3 or more. ECG positivity was considered as ST₆₀ segment depression of 0.1 mV or more from the reference level in any lead. Adenosine echo test was positive in 22 out of 26 patients and exercise echo in 19 (sensitivity 85% and 73%, respectively, p=NS). Adenosine ECG test was positive in 14 of 26 patients and exercise ECG test in 21 (sensitivity 54% and 81% respectively, p= NS). In three patients with normal coronary arteriography adenosine echo was negative in all three, exercise echo, adenosine ECG and exercise ECG in two. Side effects due to adenosine infusion were always minor, well tolerated by the patients and disappeared within seconds after termination of infusion. The present study suggests that adenosine test is at least as useful as exercise echo test in the provocation of myocardial ischemia in patients with coronary artery disease and stable angina pectoris.     

Technical and Clinical Aspects of Coronary Computed Tomography Angiography

Coronary computed tomography angiography is an emerging imaging technique that has attracted much scientific attention over the past years. Improved scanner technology and dedicated protocols have made noninvasive coronary a reliable diagnostic test in patients with suspected coronary artery disease (CAD). Several technical steps such as the introduction of 64-slice scanners, multisegment reconstruction, and dual-source computed tomography have substantially improved temporal and spatial resolution. With these sophistications, coronary computed tomography angiography enables reliable exclusion of CAD in patients with low to intermediate pretest probability of having CAD or with inconsistent ischemia test results.     

Exercise tests in unstable angina suspects

The review is devoted to exercise tests (ET) potential in patients with different forms of coronary heart disease (CHD) exacerbation and suspected unstable angina. It is well known that unstable angina untreated pharmacologically is a contraindication for ET. Of interest in clinical practice is diagnosis, risk assessment and treatment policy in patients with chest pain. The main focus is on ET conduction in unstable angina suspects with low and intermediate risk, on safety and validity of ET conduction in these patients.     

The Effect of Rate Responsive Pacing in Patients with Angina Pectoris on the Extent of Ischemia on 201-Thallium Exercise Scintigraphy

VAN CAMPEN, L.C.M.C., et al. : The Effect of Rate Responsive Pacing in Patients with Angina Pectoris on the Extent of Ischemia on 201-Thallium Exercise Scintigraphy. In patients with coronary artery disease (CAD), rate responsive pacing is considered to be contraindicated because an increase in heart rate may increase oxygen demand. Although previous studies have shown no subjective increase in ischemia during rate responsive pacing, data from objective assessment have not been documented. The goal of this study was to determine if there was an increase in ischemia on 201-Thallium (²⁰¹TI) exercise scintigraphy in this mode of pacing in patients with CAD and angina. Eighteen consecutive patients with chronic atrial fibrillation and symptomatic bradyarrhythmias with a pacemaker for more than 6 months participated in the study. In VVI and VVIR modes a symptom-limited exercise ²⁰¹TI scintigram was performed in a single blind randomized crossover fashion. Exercise duration, anginal attacks, use of nitroglycerine (NTG) tablets, blood pressure, and analysis of the scintigrams were assessed during each pacing mode. Fifteen men and three women were included (  age 65.9 ± 4.9 years, LVEF 0.44 ± 0.07  ). Four were in Class III angina pectoris, and 14 in class II. The mean exercise duration increased 28% in the VVIR group without an increase in anginal attacks per week or the use of NTG tablets. On scintigrams, no differences were seen between the two groups. One patient was withdrawn from the study because of an increase in angina pectoris (AP) attacks during VVIR pacing. Rate responsive pacing is safe and effective in patients with CAD without an increase in subjective and objective signs of ischemia.     

Plasma levels of cyclic GMP and endothelin in postmenopausal women with unstable coronary artery disease.

Many women with typical anginal chest pain have normal coronary angiograms, which may be due to altered endothelial function. We evaluated the endothelial markers cyclic GMP (cGMP) and immunoreactive endothelin (ir-ET) regarding presence of coronary atherosclerosis in women with clinical signs of unstable coronary artery disease (CAD). Plasma levels of cGMP and ir-ET were determined in 118 patients and 84 controls. Ischaemia was evaluated at an exercise test. Of the patients 20% had normal vessels, 14% insignificant CAD and 66%, significant stenosis at coronary angiography. Mean (95% CI) concentration of cGMP (nmol/l) was higher in patients than in controls (5.05 (4.53; 5.58) vs. 3.79 (3.34; 4.23)). Separating patients according to daily intake of nitroglycerin, only patients with this medication had significantly higher cGMP level (5.73 (4.88; 6.58)), whereas the difference between those without (4.35 (3.76; 4.94)) and controls disappeared. Patients with ischaemia at exercise test had higher cGMP level than those without (6.01 (5.13; 6.88) vs. 4.30 (3.66; 4.94)), even after adjusting for nitroglycerin treatment. ir-ET (pmol/l) was lower in patients with normal vessels than patients with coronary atherosclerosis (0.83 (0.78; 0.88) vs. 0.98 (0.92; 1.04)) and than the control group (0.91 (0.87; 0.94)). The difference between the control group and patients with atherosclerosis was also significant. Patients with unstable CAD and long-term nitroglycerin treatment have increased cGMP level. Patients with exercise-induced ischaemia have higher cGMP level than those without, irrespective of nitroglycerin treatment, which may reflect a general compensatory mechanism. Patients with normal vessels have low level of ir-ET, indicating different mechanisms for ischaemia/angina in these patients compared with patients with atherosclerosis.     

平板运动试验在诊断女性冠状动脉疾病中的临床意义

目的：评价平板运动试验(treadmill exercise testing，TET)在诊断女性冠状动脉疾病(coronary artery disease，CAD)中的应用价值。方法：回顾性分析1995年3月-2002年11月在本院作冠状动脉造影(coronary arteriography,CAG)并同时行TET检查的104例女性患的临床资料。TET检查采用日本国立心血管疾病中心(NCVC)制定的方案，评价指标包括ST段压低程度、运动后3min收缩期血压(SBP)与运动高峰时SBP比值[SBP比(3’)]和是否发生心绞痛(angina pectoris，AP)。结果：单用ST段压低作为诊断指标，其灵敏度为98．2％，特异度为4．2％；ST段压低结合SBP比(3’)时，其灵敏度为83．9％，特异度为89．6％；ST段压低结合AP作为诊断指标，其灵敏度为89．3％．特异度为95．8％。结论：ST段压低与SBP比(3')及AP的综合评估可提高TET对女性CAD的临床诊断的准确性。