[Stress myocardial scintigraphy in the pre- and postoperative diagnosis of ischemic cardiopathy. The correlations between the clinical aspects and the coronary angiographic picture].

With radioisotopes it is possible to study the heart obtaining complementary or substitutive informations to those provided by the most common noninvasive methods of myocardial assessment and by coronarography. This paper aim is to report experience with thallium 201 and 99mTc isonitrile in the diagnosis and followup of ischemic heart disease, in particular correlating clinical, coronarographic and scintigraphic findings. MATERIAL AND METHODS. During the biennium 1989-91 we have used the myocardial perfusion imaging with thallium 201 in 29 patients (20 male age ranging from 40 to 60 years) injecting 2 mCi at exercise peak with immediate planar mapping, followed by a second registration at rest 4 hours later (thallium 201). Imaging with 99mTc SESTAMIBI has been carried out in 6 patients (two of whom previously studied with thallium 201) injecting 20-22 mCi both at stress peak and at rest, with SPECT mapping 60'-90' later. All these patients presented specific problems for the diagnosis of myocardial ischemia. The exercise testing has been performed by a bicycle ergometer and with a standardized procedure increasing every two minutes the workload to the maximum tolerated according to the clinical conditions and to the response. All antianginal treatments were discontinued for at least 48 hours before testing and the patients were fasted for 6 hours. The images were obtained using a small field scintillation camera with a low-energy general purpose collimator. We divided the patients in 4 groups: Group A. Six patients who had an open heart operation: in 5 coronary revascularization was carried out (plus left ventricular aneurysmectomy in one and plus aortic valve replacement in another); in 1 patient an aortic valve replacement was performed on. Group B. Six patients have been evaluated after coronary angiography. Group C. Seventeen patients with doubtful diagnosis of myocardial ischemia on the base of the symptoms and/or non invasive testing as rest or stress electrocardiogram (ECG). Group D. In 6 more patients (2 of those previously studied with thallium 201) the myocardium has been assessed with SESTAMIBI. RESULTS. In one patient of the group A the thallium 201 images detected silent ischemia; in 5 removed the diagnostic doubts of the ECG findings owing to left ventricular overload or to old infarctions in 2 patients and to electrolytes disturbances or pharmacological effects in 3 patients. In group B patients the thallium 201 further on could assess the extent of ischemic and necrotic areas suggesting the final indications to angioplasty in 3 patients, medical treatment in 2 and surgery in 1. We could not find correlations between the extent of the disease predicted by the coronarography and the findings of the thallium 201 images. In the diagnosis of myocardial ischemia, group C, the Thallium 201 has been very useful and specific excluding an ischemic origin in 4 patients with arrhythmias, in 2 patients without symptoms of angina but with doubts at rest and exercise ECG findings and in 4 with atypical thoracoalgia and doubtful ECG. On the contrary, this test could give the final diagnosis of ischemia in 6 patients displaying its sensitivity in detecting coronary artery disease. Among the patients assessed with SESTAMIBI, in 2 this test has been essential in evaluating the myocardial contractility and the segmental wall motion. DISCUSSION. The usefulness of Thallium 201 imaging, as a very sensitive mean in detecting coronary artery disease and in the assessment of myocardial viability, is well known. Although the most common indications of this technique are well standardized, in the clinical practice there are many situations in which the thallium 201 can contribute to the diagnosis and to the management. (ABSTRACT TRUNCATED)