Diagnostic value and incremental contribution of bicycle exercise, first-pass radionuclide angiography, and 99mTc-labeled sestamibi single-photon emission computed tomography in the identification of coronary artery disease in patients without infarction

BACKGROUND

The diagnostic value and incremental contribution of different noninvasive tests to the identification of coronary artery disease in 128 patients from a general population with intermediate pretest likelihood (48.0%) were determined by ordered logistic regression analysis and receiver-operating characteristic (ROC) curves.

METHODS AND RESULTS

Patients referred for suspicion of coronary heart disease were submitted to bicycle exercise testing under clinical and electrocardiographic control. AT peak exercise, first-pass radionuclide angiography was performed after injection of 99mTc-labeled sestamibi, followed by single-photon emission computed tomographic (SPECT) acquisition. A comparative rest study was obtained within 1 week, and qualitative and quantitative analysis was applied to assess the presence and extent of disease. With coronary angiography and 50% stenosis used as a standard, the discriminative accuracy of each test was calculated. The accuracies to diagnose coronary heart disease were 71.3% +/- 4.7% for the bicycle test, 66.7% +/- 5.3% for radionuclide angiography, and 81.6% +/- 3.9% for the SPECT data. By ROC curves, the optimal criteria for positivity were determined for the visual and quantitative analysis for both presence and extent of coronary artery disease. Results of visual and quantitative SPECT were compared in terms of area under the ROC curves. The diagnostic performances showed no significant difference, ranging from 74.3% to 81.6%. The first-pass radionuclide angiographic and SPECT data were added progressively to the stress testing to evaluate their incremental diagnostic contribution. Only the addition of SPECT results significantly increased the accuracy to 85.6% +/- 3.3% (p < 0.0001).

CONCLUSION

Exercise electrocardiography and first-pass radionuclide angiography showed comparable accuracy to detect coronary artery disease. However, the combination of exercise testing and visual SPECT analytic data sufficed to ensure diagnostic accuracy, without significant benefit from the addition of other tests or the application of quantification.

Escherichia coli endocarditis of a native mitral valve with paravalvular pseudoaneurysm formation and fatal hemopericardium

Until recently only few cases have been described of acute infective endocarditis with E. Coli limited to a normal native mitral valve. Furthermore, mechanisms of so called abcess formation and rupture are still uncompletely understood. We report the case of an E. Coli endocarditis developing a rapidly progressive pseudoaneurysm of the mitral annulus. At necropsy diffuse infectious tissue weakening with pseudoaneurysm formation of the mitral ring and dissection into an hemorraghic pericard were seen. The authors further discuss the changing pattern of infectious agents causing acute infective endocarditis of the native mitral valve, transesophageal echocardiographic characteristics of paravalvular cavities and insights in mechanisms of pseudoaneurysm formation and dissection from clinicopathological findings.

Improvement in the efficacy of exercise first-pass radionuclide angiocardiography in detecting coronary artery disease and the effect of patient age

The most widely used criterion of normality during exercise radionuclide angiocardiography (a five EF units increase in left ventricular ejection fraction from rest to exercise) has been established in young, healthy volunteers resulting in a relatively low specificity when applied to older, less fit patients or in women. In a group of 57 patients ranging in age from 22 to 79 years with a low likelihood of coronary artery disease, the age of the patient was the only independent variable predicting left ventricular ejection fraction change during exercise. The efficacy of a new age-based criterion for the diagnosis of coronary artery disease was then evaluated in 115 patients with chest pain undergoing both exercise first-pass radionuclide angiocardiography and coronary arteriography. Compared to the classic five EF unit criterion, the age-based criterion had a higher specificity (73.2% vs 34.1% P less than 0.001) without significant loss in sensitivity (85.1% vs 92.6%; P = NS).

Comparison between exercise myocardial perfusion and wall motion using 201Tl and 191Irm simultaneously

By exploiting the ultrashort half-life 191Irm as tracer for left ventricular first-pass angiocardiography and 201Tl as myocardial perfusion agent, direct comparison between myocardial perfusion and regional wall motion was obtained during the same exercise stress test in patients with non-significant coronary artery disease, in patients with recent myocardial infarction, and in patients six weeks after successful percutaneous transluminal coronary angioplasty (PTCA). A good agreement between regional myocardial perfusion and regional wall motion was observed in patients with non-significant coronary artery disease and in most patients with recent myocardial infarction. In contrast, discrepancies occurred at maximal exercise in patients studied six weeks after successful PTCA: only 38% of the patients with no evidence of restenosis and with a completely normal myocardial perfusion scintigraphy had a normal regional wall motion at maximal exercise stress. According to these results, a normal uptake of 201Tl six weeks after PTCA would mean that the circulation has been successfully reestablished but without predicting the functional capacities of the myocardial cells which remain altered at least six weeks after the revascularization procedure in about two-thirds of the patients. We conclude that 191Irm in combination with 201Tl offers the opportunity of performing myocardial perfusion and wall motion studies simultaneously both at rest and during exercise.

Microfistulas from the left anterior interventricular coronary artery percolating the ventricular septum

We report a case with microfistulas originating from interventricular septal branches of the left anterior descending coronary artery and emptying in the right ventricle. To our knowledge, this anomaly has never previously been described.

Diagnosis of aortic dissection. Comparison of investigatory methods--case report

A case is presented of a patient with an acute aortic dissection, rapidly followed by thrombosis of the false channel. The classical aortoangiography failed to give adequate information, whereas newer, less invasive investigation methods gave images that finally led to the correct diagnosis. The value of these methods in the diagnosis of aortic dissection is discussed.

Effects of benfluorex on patients with endogenous hypertriglyceridaemia

Twenty-two patients showing persistent endogenous hypertriglyceridaemia after an individually designed diet for 1 month were randomly divided into two groups. Each was treated during two crossover consecutive 40-day periods, either starting with benfluorex (450 mg/day) or with placebo. They were followed as out-patients and were investigated at the start of the study, and at the end of each treatment period. A number of laboratory measurements were undertaken at each visit, including triglycerides, cholesterol, uric acid, fatty acids, and glucose and insulin after an oral glucose tolerance test. The results showed a significant (p less than 0.01) reduction in triglyceride blood levels of 32.7% after benfluorex treatment compared to 11.7% with placebo, irrespective of the treatment order. Other laboratory measurements were in the normal range, and there were no significant changes, except for uric acid which showed a small decrease but of little clinical significance. Benfluorex would appear to have an important therapeutic effect on endogenous hypertriglyceridaemia.

Systolic time intervals: a valuable parameter of thyroid function

Conventional systolic time interval measurements were made in 49 patients presenting with hypertyroidism, euthyroidism, or hypothyroidism. A linear correlation was observed over the entire range of thyroid function ( r = 0.75) between Δ PEP and the serum free T4 index. A linear correlation was also found between the PEP/LVET ratio and the serum free T4 index ( r = 0.70). A higher correlation was found between the PEP/LVET ratio and the serum free T4 index when plotted logarithmically ( r = 0.75).

During treatment of hyperthyroidism, the PEP progressively lengthens and the PEP/LVET ratio increases, whereas during treatment of hypothyroidism the PEP shortens progressively to normal values while the PEP/LVET ratio diminishes.

In amiodarone-induced hyperthyroidism, both a prolonged PEP and an increased PEP/LVET ratio were found. These controversial measurements, suggesting a diminished cardiac contractility, may be explained by a worsened cardiac ischemia due to the development of hyperthyroidism.

Systolic time interval measurements appear to be a valuable tool in the assessment of the cardiac response to thyroid hormone during both hypothyroidism and hyperthyroidism.

Metabolic effects and anti-obesity action of fenfluramine in prolonged-acting form

In a single-blind trial, 15 obese patients, selected because of their poor response to a weight reducing diet, were treated for 1 month with placebo plus a 1600 calorie diet and then for a further 2 months with a single daily dose of 120 mg fenfluramine plus diet. After the placebo period, the mean weight loss was only 0.89 kg. After the 2-month period on fenfluramine, there was a highly significant (p less than 0.001) additional mean weight loss of 10.18 kg. Biological investigations of the metabolic effects of fenfluramine showed that compared with the placebo period there was an improved glucose tolerance and insulin response after active treatment as well as statistically significant decreases in serum cholesterol (p less than 0.001) and triglycerides (p less than 0.01). During active treatment none of the patients complained of feeling hungry and only a few transient side-effects were reported at the start.