Kvalitativna i semikvantitativna analiza perfuzione scintigrafije miokarda u dijagnostici, proceni težine i lečenju koronarne bolesti
AuthorStević, Miloš Lj.
Committee membersKoraćević, Goran
MetadataShow full item record
Introduction Coronary heart disease takes the first place in morbidity and mortality worldwide. As this disease increasingly affects younger people, especially in underdeveloped and developing countries, great efforts are being made aimed at prevention, early detection and treatment of coronary artery disease (CAD). Prevention of coronary heart disease is aimed at modifying risk factors such as obesity, physical inactivity, diabetes, and smoking tobacco, the role of which in the pathogenesis of this disease has unequivocally been proven. On the other hand, the diagnosis of coronary artery disease increasingly involves different methods of imaging in medical diagnostics, while percutaneous interventions are more oriented towards the therapy in terms of eliminating the causes of myocardial ischemia due to stenosis or occlusion of the coronary arteries. Myocardial perfusion scintigraphy with single photon emission tomography is non-invasive nuclear medicine diagnostic method by means of ...which it is possible to determine the possible existence of ischemic changes in the myocardium of the left ventricle, resulting from the existence of stenosis or occlusion of the coronary arteries in patients with existing symptoms, and in asymptomatic patients with existing risk factors. Aim The aim of this study was to estimate diagnostic accuracy of myocardial perfusion scintigraphy with single photon emission tomography in early detection of coronary artery disease in four groups of patients: the patients suspected of the existence of ischemic heart disease at moderate risk of existence of coronary artery disease without previous history; the patients suffering from diabetes mellitus at moderate risk of existence of ischemic heart disease without previous history of coronary artery disease; the patients who underwent non-surgical methods of treatment of coronary artery disease by means of transluminal percutaneous approach; and the patients who underwent surgical method of treatment of coronary artery disease. Kvalitativna i semikvantitativna analiza perfuzione scintigrafije miokarda u dijagnostici proceni težine i lečenju koronarne bolesti Miloš Stević doktorska disertacija 2015 9 Patients and methodology The study included patients with a moderate risk of coronary artery disease assessed by pretest probability calculated by means of the Duke Clinical Score's. The total number of examined patients was 394, 215 men and 179 women, mean age 59.4 ± 9.9 years who were divided into the following groups: patients with moderate risk of the existence of myocardial ischemia, without previously detected coronary artery disease (AP group, 258 patients); patients suffering from diabetes mellitus with moderate risk of myocardial ischemia, without previously detected coronary heart disease (DM group, 57 patients); patients who previously underwent non-surgical method of treatment of coronary artery disease (PCI group, 52 patients) and patients who underwent surgical method of treatment of coronary artery disease (BP group, 27 patients). All patients underwent myocardial perfusion scintigraphy with single photon emission tomography (SPECT MPI) made by two-day protocol. SPECT MPI was performed on double headed gamma camera. On the first day of the study application of radiopharmaceuticals was done immediately after the termination of exercise treadmill testing, while on the second day the study was done at resting state. In patients with perfusion defects recorded on stress study application of radiopharmaceuticals was preceded by a diagnostic application of coronary dilators at the rest study, in order to assess the viability of the affected myocardial ischemia. Application of dilators was made sublingually. Scintomograms obtained with SPECT MPI studies were evaluated qualitatively in terms of the existence of perfusion defects, which was a pathological finding. Quantitative parameters (summed score in stress, summed score at rest, summed difference score, diastolic and systolic volumes of the left ventricle, left ventricular ejection fraction, transient ischemic dilation of the left ventricle, schematic view of coronary artery irrigation zone, the percentage of affected myocardial perfusion defect) were determined by 4DMSPECT software package for quantification. Coronary angiography was performed in 128 patients, in 30 of 258 from the AP group, in 27 of 57 from DM groups, in 49 of 52 patients from the PCI group and in 22 of 27 subjects BP group. Finding on coronary angiography was categorized in group with stenosis under 30%, stenosis between 30% and 69%, and stenosis over 70% of coronary artery. Comparison of findings was done using statistical analysis software package, IBM® SPSS® Statistics 20. Values are shown as mean ± standard deviation or as individual values. For testing the significance of differences in mean values of independent samples, method of analysis of variance (ANOVA) was used. To test the differences in mean values of the same group in the repeated measurement Student paired t-test was used. To test the difference Kvalitativna i semikvantitativna analiza perfuzione scintigrafije miokarda u dijagnostici proceni težine i lečenju koronarne bolesti Miloš Stević doktorska disertacija 2015 10 between proportions Pearson Χ2 test was used. Sensitivity, specificity, positive and negative predictive value and diagnostic accuracy of SPECT MPI findings were calculated in relation to coronary angiography Results By comparing SPECT MPI with coronary angiographic findings under presumption that the level of stenosis of coronary artery of 70% was considered abnormal, the following results were obtained: 89% sensitivity, 42% specificity, 86% positive predictive value, 50% negative predictive value and 74 overall diagnostic accuracy. Correlation of findings obtained on coronarography with SPECT MPI method, with stenosis of coronary arteries obtained in coronarograms of 30% to 69%, for all four groups of patients showed 91% sensitivity of SPECT MPI, 100% specificity, 100% positive predictive value, 50% negative predictive value and 91% of overall diagnostic accuracy of the method. Discussion Reversible perfusion defects that indicate the existence of myocardial ischemia, which were found in patients without the existence of the specific anginal symptoms, coincided with the detection of "silent" myocardial ischemia. Type of myocardial ischemia that exists without symptomatology, occurs in the general population, and in specific populations of the patients such as those suffering from diabetes. The result corresponding to the facts found in the literature about the existence of "silent" myocardial ischemia was detected in our study. Detection of fixed perfusion defects corelated with the existance of clinicaly ―silent‖ fibrotic altered myocardium, recognised in the literature. Getting perfusion defects on myocardial perfusion scintigraphy in patients in which we had detected anatomically insignificant stenosis of the coronary arteries, explains precisely the existence of hemodynamic significance of stenosis. Comparing the results of myocardial perfusion scintigraphy with the existence or absence of stenosis in coronary angiography, when as a diagnostic tool for assessing the significance of stenosis was value of over 70%, the resulting parameters of diagnostic accuracy of nuclear medicine method was slightly lower. However, comparing the results obtained with myocardial perfusion scintigraphy with the results of coronary angiography, when presence of coronary artery stenosis of 30% to 69% was encountered, high sensitivity, specificity, positive and negative predictive value, and overall diagnostic accuracy of nuclear medicine method was achieved in diagnosis of coronary artery disease. Kvalitativna i semikvantitativna analiza perfuzione scintigrafije miokarda u dijagnostici proceni težine i lečenju koronarne bolesti Miloš Stević doktorska disertacija 2015 11 Conclusion The results provide information about great importance of SPECT MPI in detection of myocardial ischemia in the group of patients with intermediate risk of coronary artery disease. SPECT MPI has proven to be significant in detecting "silent" myocardial infarction in the same group of patients. In addition, it has turned out to be a reliable diagnostic tool in the detection of ischemia, in asymptomatic patients suffering from diabetes mellitus. The results of SPECT MPI studies in patients with DM without previous detection of coronary disease are extremely useful for strategy plan both in terms of additional diagnostics and adequate therapeutic approach. SPECT MPI has shown to be a reliable method in terms of selection of PCI patients for repeated invasive diagnostic and therapeutic non-surgical method of treatment of newly developed myocardial ischemia. At the same time, SPECT MPI shows its importance in assessing the selection of patients who would not benefit from the repeated PCI, whereby invasive diagnostic and therapeutic procedures are avoided. High sensitivity of SPECT MPI procedures is of great importance in the evaluation and selection of patients with ischemia after BP procedures in planning invasive diagnostics and therapy for the treatment of newly developed myocardial ischemia. Correlation of SPECT MPI studies and coronarography showed high sensitivity, specificity, positive and negative predictive value, as well as high overall accuracy of the procedure in AP, DM, PCI and BP groups of patients. This result suggests that SPECT MPI is of great importance in detecting ischemic heart disease in all groups of patients, and that it is an important diagnostic tool in the evaluation and planning of the therapeutic approach in patients with CAD.