Probability Of Ischemia Research Articles

Clinical judgement in chest pain: a case report\xa0

BackgroundCardiac stress testing is a validated diagnostic tool to assess symptomatic patients with intermediate pretest probability of coronary artery disease (CAD). However, in some cases, the cardiac stress test may provide inconclusive results and the decision for further workup typically depends on the clinical judgement of the physician. These decisions can greatly affect patient outcomes.Case presentationWe present an interesting case of a 54-year-old Caucasian male with history of tobacco use and gastroesophageal reflux disease (GERD) who presented with atypical chest pain. He had an asymptomatic electrocardiogram (EKG) stress test with intermediate probability of ischemia. Further workup with coronary computed tomography angiography (CCTA) and cardiac catheterization revealed multivessel CAD requiring a bypass surgery. In this case, the patient only had a history of tobacco use but no other significant comorbidities. He was clinically stable during his hospital stay and his testing was anticipated to be negative. However to complete workup, cardiology recommended anatomical testing with CCTA given the indeterminate EKG stress test results but the results of significant stenosis were surprising with the patient eventually requiring coronary artery bypass grafting (CABG).ConclusionAs a result of the availability of multiple noninvasive diagnostic tests with almost similar sensitivities for CAD, physicians often face this dilemma of choosing the right test for optimal evaluation of chest pain in patients with intermediate pretest probability of CAD. Optimal test selection requires an individualized patient approach. Our experience with this case emphasizes the role of history taking, clinical judgement, and the risk/benefit ratio in deciding further workup when faced with inconclusive stress test results. Physicians should have a lower threshold for further workup of patients with inconclusive or even negative stress test results because of the diagnostic limitations of the test. Instead, utilizing a different, anatomical test may be more valuable. Specifically, the case established the usefulness of CCTA in cases such as this where other CAD diagnostic testing is indeterminate.

Spatial indices of repolarization correlate with non-ST elevation myocardial ischemia in patients with chest pain

Background Mild-to-moderate ischemia does not generally result in ST segment elevation on the ECG, but rather it frequently results in non-specific, dynamic changes in the T wave. These repolarization changes are frequently considered non-diagnostic for ischemia, warranting further diagnostics that are costly and time-consuming. Robust methods to quantify such T wave heterogeneity can have immediate clinical applications. We sought to evaluate the effects of spontaneous ischemia on the evolution of spatial T wave changes in patients undergoing nuclear cardiac imaging for evaluating intermittent chest pain. Methods We recruited non-traumatic chest pain patients (> 30 years old) referred for 2-stage, stress-rest, single-photon emission computed tomography (SPECT) scans to rule out focal myocardial ischemia. At baseline, consented subjects underwent 5-min, 12-lead ECG recordings using high-fidelity, digital ECG Holters (H12 + recorders, 1,000 s/s, 0.05–300 Hz, Mortara Instrument). Subjects then underwent a symptom-limited cardiac stress test with an abrupt recovery protocol (lying down supine when reaching peak test), where we recorded another 5-min peak-stress/recovery ECG while in supine position. After excluding those with LBBB or pacing, spatial variations in repolarization were quantified using T wave complexity (TWC) based on the eigenvalues of the spatial correlation matrix of the ECG (ratio of second to first eigenvalues of repolarization). Calculations were based on 10-second averaged beats, and we computed an ischemia change index based on the relative variation in TWC during peak stress to the normal variability observed in baseline recording. Results Our sample included 30 males and 20 females aged 63 ± 11 years. One in five patients developed mild-to-moderate ischemia on their stress SPECT scans. Although there were no differences in TWC values between groups at baseline, significant changes in TWC were seen during the entire peak-stress/recovery period in patients with active ischemia (n = 10), but not in those with negative ischemia (n = 40). Using a support vector machine model based on the ischemia change index, we predicted pre-SPECT probability of ischemia with a sensitivity of 0.8571 and specificity of 0.8000. Interestingly, we also observed that the magnitude of change in the ischemic index followed a pattern that depends on the severity of ischemia (greater dispersion with moderate ischemia) and the anatomic distribution of ischemic region (greater dispersion with LAD and LCX disease). Conclusions Our findings demonstrate that ischemia-induced changes in T wave morphology can be meaningfully quantified from the surface 12-lead ECG, suggesting an important opportunity for improving diagnostics in patients with chest pain.

Exaggerated hypertensive response to exercise and myocardial ischemia in patients with known or suspected coronary artery disease

ObjectivesThe association between an exaggerated hypertensive response to exercise (EHRE) and the probability of ischemia in stress tests is controversial. Our purpose was to determine the possible association between an EHRE and the development of chest pain and electrocardiographic or echocardiographic ischemia with exercise. Patients and methodsA retrospective observational study was conducted of 10,047 patients with known or suspected coronary artery disease referred for exercise echocardiography. A logistic regression analysis assessed the effect of developing an EHRE (defined as a maximum systolic blood pressure with exercise ≥220mmHg) and the onset of chest pain and electrocardiographic and echocardiographic changes suggestive of ischemia. ResultsA total of 402 patients developed an EHRE. The rates of angina, electrocardiographic ischemia and echocardiographic ischemia among the patients with an EHRE were 8.2, 16.2 and 22.6% versus 13.8, 14.7 and 27.5%, respectively, for patients without an EHRE (p=.001, p=.4, p=.032). After a multivariate fit, EHRE was associated with a lower probability of exercise-induced angina (OR, 0.44; 95% CI 0.30–0.65; p<.001) and echocardiographic ischemia (OR, 0.63; 95% CI 0.48–0.83; p=.001) but not with the onset of electrocardiographic ischemia. ConclusionsEHRE is associated with a lower prevalence of angina and echocardiographic ischemia in patients with known or suspected coronary artery disease.

Respuesta hipertensiva exagerada al ejercicio e isquemia miocárdica en pacientes con enfermedad coronaria conocida o sospechada

ObjectivesThe association between an exaggerated hypertensive response to exercise (EHRE) and the probability of ischaemia in stress tests is controversial. Our purpose was to determine the possible association between an EHRE and the development of chest pain and electrocardiographic or echocardiographic ischaemia with exercise. Patients and methodsA retrospective observational study was conducted of 10,047 patients with known or suspected coronary artery disease referred for exercise echocardiography. A logistic regression analysis assessed the effect of developing an EHRE (defined as a maximum systolic blood pressure with exercise ≥220mmHg) and the onset of chest pain and electrocardiographic and echocardiographic changes suggestive of ischaemia. ResultsA total of 402 patients developed an EHRE. The rates of angina, electrocardiographic ischaemia and echocardiographic ischaemia among the patients with an EHRE were 8.2, 16.2 and 22.6% versus 13.8, 14.7 and 27.5%, respectively, for patients without an EHRE (p=.001, p=.4, p=.032). After a multivariate fit, EHRE was associated with a lower probability of exercise-induced angina (OR, 0.44; 95% CI 0.30-0.65; p<.001) and echocardiographic ischaemia (OR, 0.63; 95% CI 0.48-0.83; p=.001) but not with the onset of electrocardiographic ischaemia. ConclusionsEHRE is associated with a lower prevalence of angina and echocardiographic ischaemia in patients with known or suspected coronary artery disease.

Abstract P273: Does Coronary Vessel Dominant System Dictate False Positive Results in Nuclear Stress Imaging?

Objective: We sought to investigate whether the coronary vessel dominance dictates the false positive results in nuclear stress imaging. Background: Atherosclerotic coronary artery disease is the leading cause of morbidity and mortality in men and women in the United States. Myocardial perfusion imaging (MPI) has provided incremental diagnostic and prognostic information in evaluation of patients with suspected or known coronary artery disease. It has a sensitivity of 87% but specificity of 64%. Tissue attenuation secondary to diaphragm or breast have been documented as a cause of false positive tests. It is also believed that patients with a left dominant coronary system are more prone to have a false positive test, however there is no conclusive literature available supporting this. Methods: A retrospective analysis was performed of all patients who underwent coronary angiography from January 2006 to December 2008, who had intermediate to high probability of ischemia as assessed by MPI. The location and the size of ischemia were documented. Patients were classified as either true positive (TP) or false positive (FP) based on presence of significant coronary stenosis (&gt;50%) by angiography. Furthermore, coronary vessel dominance (right, left or mixed) was documented. Results: A total of 991 patients were included in the analysis. 901 patients had a TP test (91%). As expected, females had a significantly higher FP rate compared to males (16.1% vs. 4.6%, p&lt;0.05).The population was divided into three groups, right, left and co-dominant system: 855, 93 and 43 patients respectively. There was no difference in the FP rate between the right and co-dominant systems (8.1% vs. 7.5%, p=0.7). Patients with left dominant systems were noted to have higher rate of false positive (12.9%) however, this did not achieve statistical significance (p=0.1). When location of lesion was taken into consideration, the far majority (92%) of anterior wall FP cases were females, regardless of system dominance. Conclusion: This is preliminary study supported previous study that female have a higher FP test on their MPI. Furthermore, patients with left dominant system are more prone for FP than either co dominant or right dominant system, especially in females.

Depression and increased myocardial ischemic activity in patients with ischemic heart disease

Background Depression is relatively common in patients with ischemic heart disease (IHD) and is associated with increased risk of mortality and morbidity. However, the mechanisms by which depression adversely affects clinical outcomes of patients with IHD are unknown. This study examined the relationship between depression and myocardial ischemia during mental stress testing and during daily living in patients with stable IHD. Methods and results The Center for Epidemiological Studies-Depression scale (CES-D) was administered to 135 patients with IHD to evaluate depressive symptoms. Radionuclide ventriculography was used to evaluate the occurrence of left ventricular wall motion abnormality (WMA) during mental stress and exercise testing. Forty-eight-hour ambulatory electrocardiography was used to assess myocardial ischemia during daily living. The mean CES-D score was 8.2 (SD 7.4, range 0-47) with a median of 7. Logistic regression models using restricted cubic splines revealed a curvilinear relation among CES-D scores and the probability of ischemia. For patients with CES-D scores ≤19 (81.5% of study population), a 5-point increment in the CES-D score was associated with roughly a 2-fold increase in the likelihood of ischemia during mental stress. For patients with CES-D scores >19, the relation among scores and ischemia during mental stress tended to be inversely related, but the portion of the sample is very small. Similar patterns of results were noted for CES-D scores and ischemia during daily life. Conclusions Patients with mild to moderate depressive symptoms (CES-D scores ≤19) are more likely to exhibit myocardial ischemia during mental stress testing and during daily living. Myocardial ischemia may be one mechanism by which depression increases the risk of mortality and morbidity in patients with IHD. The observed inverse association between higher level of depressive symptoms and ischemic activity needs to be further assessed in large samples.

Was it infarction or haemorrhage?

Since the clinical distinction between haemorrhagic and ischaemic stroke cannot be achieved with a simple clinical evaluation, and it is virtually impossible to submit all stroke patients to CT, a weighted clinical score may offer some advantages to physicians who are involved in stroke management. The Allen score (also referred to as the Guy's Hospital score), a validated clinical score, has been tested in two different clinical settings, comprising 289 patients. When only the values under 4 and those over 24 are taken into account (i.e. ‘> 90% probability of ischaemia and haemorrhage), the global accuracy of the score is 97%, and the diagnostic gain (given a pretest probability for haemorrhage of 11% and a likelihood ratio of 194) is 85%. Therefore, we conclude that this simple clinical method can be used for epidemiological studies of stroke incidence and outcome, as well as for a first bedside screening to decide which patients should have priority for CT.

201TI Myocardial SPECT and ß-Endorphin Levels in Patients with Suspected Silent Ischemia

Today silent myocardial ischemia (SMI) is a well-recognized phenomenon. However, in the absence of clinical signs suggesting coronary artery disease (CAD), a streamlined diagnostic approach for precise clarification has proved to be difficult. Sensitivity and specificity of ergometric results are rather poor in symptom-free patients. Thus the question arises, whether the necessity of coronary angiography can be established more precisely by 201Tl myocardial SPECT in these patients. Treadmill exercise according to the Bruce protocol, 201Tl myocardial SPECT and coronary angiography were performed in a total of 106 patients with suspected SMI. In group I (high probability of ischemia; n = 46), reversible defects detected by SPECT correlated well with significant stenoses and irreversible defects with subtotal stenoses or complete occlusions. SPECT sensitivity in the detection of ischemia was 91%, its specificity 96%. In group II (low probability of ischemia; n = 60), SPECT sensitivity was as high as in group I (94%) but due to a high number of false-positive results (e.g. cardiomyopathy) specificity was only 75%. However, SPECT was superior to exercise ECG (sensitivity 70%; specificity 56%) in the detection of SMI. In addition, beta-endorphin levels were determined in 180 healthy subjects, 37 patients with symptomatic CAD and in 34 patients with SMI before and during maximum exercise. Exercise values in patients with SMI were significantly higher than in healthy subjects or in patients with symptomatic CAD.