Prognostic value of myocardial perfusion scintigraphy for patients suspected of and diagnosed with coronary artery disease.

BACKGROUND

The prognostic value of myocardial perfusion scintigraphy (MPS) continues to attract interest and provoke discussions.This study was an attempt to investigate the methods.

OBJECTIVE

Determination of the prognostic value of MPS for patients suspected of and diagnosed with coronary artery disease (CAD).

MATERIAL AND METHODS

The study group included 215 patients, 134 males and 81 females, aged 21-66, mean age 48. Tc-99m-MIBI myocardial perfusion scintigraphy was performed and information concerning the diagnosis, aim of the examination, past coronary episodes, clinical condition, duration and type of complaints, concomitant diseases, test results, revascularisation procedures and pharmacological treatment was gathered. Further history of the patients was monitored throughout the observation period of 52 months on average. The patients were divided into the following two groups: Group I - suspected coronary artery disease: 124 patients aged 21-65,59 males and 65 females; Group II - diagnosed coronary artery disease: 91 patients aged 31-66, 75 males and 16 females diagnosed with CAD, including 39 s/p myocardial infarct, 31s/p infarct and revascularisation, 21 s/p revascularisation. The probability of CAD was calculated using the Diamond method for the patients suspected of CAD. The obtained results were examined in a statistical analysis.

RESULTS

Normal MPS results were obtained for 94/124 patients suspected of CAD, 15/91 patients diagnosed with CAD,64/81 females and 45/134 males. In Group I, apart from pathological MPS results, reversible ischemia was determined in as many as 27/30 patients, and only 17/91 patients in Group II. No patients with normal MPS results suffered major cardiac events,only one of them underwent revascularisation. Major cardiac events occurred in the case of patients with pathological MPS results: Group I - 2 myocardial infarcts and 2 cardiac deaths,Group II - 3 infarcts and 10 cardiac deaths. Minor cardiac events, apart from one case, were also only observed in the case of patients with pathological MPS results: Group I - 10 revascularisations and one case of unstable CAD, Group II- 12 revascularisations and 7 cases of unstable CAD. Patients with normal MPS results and stenosis in coronary angioraphy suffered no cardiac events. Cardiac events occur mostly in the group with a medium and high risk of CAD and in the case of patients diagnosed with CAD.

CONCLUSIONS

1. Normal MPS results for patients suspected of or diagnosed with CAD: s/p infarct and/or CABG prognosticate a mild course of the disease, without or with a minimal number of cardiac events, also in a longer observation period.2. Pathological MPS results clearly imply a greater risk of cardiac events, and the number of events increases with the greater probability of CAD and with the patient's age. 3. Normal MPS results, even with significant stenosis in coronary angiography,prognosticate a low risk of cardiac events.