ABC | Volume 111, Nº6, December 2018

Original Article Andrade et al Prognostic Value of Myocardial Scintigraphy Arq Bras Cardiol. 2018; 111(6):784-793 the decision for the new approach was probably influenced by the initial procedure. This hypothesis was reinforced when it was observed that in the group of patients with ischemia, among the 36% who underwent the new revascularization, there was a predominance of males and, again, incomplete revascularization as an indication of MPS, and of the interval between PCI and MPS of less than 2 years. The extent of ischemia was also higher among those referred to repeated revascularization, but, unlike expected, this finding was not statistically significant. It is possible that in some cases the presence and not the extent of ischemia has been a variable with greater impact in the decisionmaking for revascularization. Regarding male gender, it shows a higher prevalence of coronary disease and greater precocity in the event occurrence; this may have contributed to the valorization of the findings and the indication of approach in the patients of this gender. Aldweib et al., 23 in the evaluation of 769 asymptomatic patients previously undergoing PCI with ischemia in MPS, subsequently referred for drug therapy or revascularization, found greater extent of ischemia and greater presence of DM among the revascularized patients. Different from the current study, the interval between PCI and MPS was similar between the groups and the presence of incomplete revascularization was not mentioned. After an average of 5.7 years, mortality rates were similar in the two treatment groups (p = 0.84). In our study, the mortality among those who revascularized was lower than those who received clinical treatment (9% × 12%), but with no statistical significance. Although this study was not designed for this purpose, and the possible impairment of the statistical analysis due to the small number of events, it is worth questioning whether the patients referred to the new revascularization would not be at greater risk and after the procedure had this risk matched to the ones targeted for clinical treatment. Although the current literature recommends the functional evaluation of asymptomatic patients after PCI only after 2 years, 2,5,16 in the present study, the clinical features and results of MPS, including perfusion findings, were similar among patients who underwent MPS in the smallest interval and in the one greater than 2 years. In this selected population, the delimitation currently recommended in 2 years did not separate distinct populations. Although incomplete revascularization is a satisfactory solution when the culprit lesion is identified and has a favorable anatomy for percutaneous approach, especially in the context of ACS, patients with remaining lesions need to be monitored and stratified, regardless of the presence of symptoms. In the present study, in this scenario MPS was shown to be a tool used in clinical practice capable of providing incremental prognostic information about the occurrence of events, directly interfering with the decision to indicate new revascularization. Previous studies 13,21 that performed MPS in the follow‑up of patients previously undergoing percutaneous revascularization described an excellent prognosis associated with normal perfusion, with an annual event rate of less than 1%. Similarly, in the current study, at the mean follow-up of 5 years, among patients with normal perfusion, the annual mortality rate was 1%, and cardiovascular mortality was 0.5%, characterizing this group as low risk. Limitations This is a single center retrospective study inwhich the patients were referred to the clinic for MPS at the recommendation of their attending physician. Therefore, extrapolation of the results should be done with caution. Another limitation is the lack of information on the type of stent used in the prior revascularization procedure in most patients. However, considering that only 11% of the procedures were performed before 2003, at which time drug‑eluting stents were introduced, and that the population was selected in a private clinic that mainly serves complementary health users with a DM prevalence of 30 %, it is believed that the stents used have been mostly drug-eluting ones. Conclusion In this study, MPS performed in asymptomatic patients after various periods of PCI was able to provide future prognostic information, the extent of the total perfusion defect was associated with a higher mortality rate and cardiovascular death, the presence and extent of ischemia were associated with higher rate of revascularization, while normal perfusion lead to an excellent prognosis with a low rate of events at the mean follow-up of 5 years. In spite of the recommendations of the guidelines, in this study, 42% of MPS were performed within less than 2 years after PCI and no relevant clinical differences were observed in relation to those who performed after this period. Author contributions Conception and design of the research and Acquisition of data: Andrade LF, Sousa AC, Peclat T, Bartholo C, Pavanelo T; Analysis and interpretation of the data and Statistical analysis: Andrade LF, Lima RSL; Writing of the manuscript: Andrade LF; Critical revision of the manuscript for intellectual content: Lima RSL. Potential Conflict of Interest No potential conflict of interest relevant to this article was reported. Sources of Funding There were no external funding sources for this study. Study Association This article is part of the thesis of master submitted by Larissa Franco de Andrade, from Universidade Federal do Rio de Janeiro. Ethics approval and consent to participate This study was approved by the Ethics Committee of the Hospital Universitário Clementino Fraga Filho under the protocol number 1643951. All the procedures in this study were in accordance with the 1975 Helsinki Declaration, updated in 2013. Informed consent was obtained from all participants included in the study. 791