ABC | Volume 111, Nº3, September 2018

Brief Communication Oliveira et al Silent cerebral infarctions in heart failure Arq Bras Cardiol. 2018; 111(3):419-422 Evaluation of transthoracic and transesophageal echocardiography The examinations were performed by two experienced echocardiographists, as recommended by the American Society of Echocardiography (ASE). 10 A commercially available device was used (Philips IE33, Philips Medical Systems, Andover, MA, USA), equipped with a 5 MHZ transducer with a multiplanar transesophageal probe. Subsequently, the images were recorded in a pen drive and reviewed by an echocardiographist. Themeasures analyzed by the Transthoracic Echocardiogram (TTE) were: diastolic and systolic diameter of the LV, anteroposterior diameter of the LA, aortic root diameter, interventricular septum and posterior wall thickness. These analyses were obtained in the parasternal short axis and the parasternal long axis planes using the M-mode. The calculation of the LVEF was carried out using the LV modified biplane Simpson's method. To perform the Transesophageal Echocardiography (TEE) images, the patient was placed in the left lateral decubitus position, and the left arm was extended over the head. The exams were performed under topical anesthesia with xylocaine spray at 10% and under intravenous sedation. The presence of spontaneous echo contrast and intracavitary thrombi were observed. The intracavitary thrombus was defined as an echodense intracardiac mass, and the spontaneous echo contrast was identified through its typical swirling movement, resembling smoke. 11 Statistical analysis The collected data were processed using the Statistical Program for Social Sciences (SPSS), version 21.0. For data analysis, descriptive statistics were used (proportions and measures of central tendency), mean and standard deviation. The Kolmogorov-Smirnov was used in the normality test. The means and proportions were evaluated by Student’s t test, according to the variable distribution. Pearson's chi-square test or Fisher's exact test was applied for association measures. Values were considered statistically significant when p ≤ 0.05 and the confidence interval ≥ 95%. Results Seventy-five patients were studied. Comparisons of clinical and echocardiographic parameters are described in Table 1. The mean LVEF was 46 ± 16.5%. Spontaneous echo contrast and intracavitary thrombi were observed in the rLVEF group (19.3%), followed by mrLVEF (15.3%) and pLVEF (9.6%). Silent cerebral infarction was observed in 14.7% of the study population (45.5% lacunar and 54.5% territorial) and was detected more frequently in patients in the rLVEF group (29%), when compared to mrLVEF (15.4%, p = 0.005). There were no cases of silent cerebral infarction in the pLVEF group. In the univariate analysis, an association was identified between silent cerebral infarction and rLVEF (Odds Ratio – OR = 8.59, 95% of Confidence Interval – 95%CI: 1.71-43.27, p = 0.009) and pLVEF (OR=0.05, 95%CI: 0.003-0.817, p=0.003). There was no association with mrLVEF (OR = 1.07, 95%CI: 0.20-5.65, p = 0.936). The association of silent cerebral infarction with diabetes mellitus (OR 4.28; 95%CI: 1.14‑16.15; p = 0.031) was also identified. Discussion In our study, patients with rLVEF had silent cerebral infarction in the territory region, and those withmrLVEF had silent cerebral infarction of the lacunar type. There was no silent cerebral infarction in patients with pLVEF. It was demonstrated that the lower the LVEF, the higher the prevalence of silent cerebral infarction. A previous study showed that reduced LVEF values are associated with patients with silent stroke (p = 0.030). 12 The prevalence of silent cerebral infarction in this study was considered small when compared to other studies of HF patients. In a study of 117 patients with HF evaluated for heart transplant, the prevalence of ischemic stroke was 34%. 13 In the study by Kozdag et al., 12 with 72 patients with ischemic dilated cardiomyopathy, the prevalence of silent cerebral infarction was 39%. However, it is worth mentioning that the high prevalence of silent infarctions in these studies was probably the result of increased HF severity in the studied populations. Another important finding was the association between diabetes mellitus and silent cerebral infarction. Chen et al. 14 found that abnormalities in early LV diastolic filling were commonly observed in diabetic patients, and the proposed mechanism includes, among other factors, microvascular disease, which may justify the data found in our study. In the case of patients with mrLVEF, silent cerebral infarctions were reported to be of the lacunar type, usually associated with cerebral small vessel disease, but eventually of embolic etiology. 15 A recent study clearly demonstrated that the clinical characteristics of mrLVEF are intermediate between pLVEF and rLVEF, or close to pLVEF or rLVEF, and suggest that mrLVEF is a transitional stage from pLVEF to rLVEF, or from rLVEF to pLVEF, rather than a distinct HF class. 16 However, data are still limited regarding these patients. Patients in the LVEFp group did not show silent cerebral infarction, differently from a study on LVEF groups, in which the rates of stroke or transient ischemic attack were slightly higher in patients with pLVEF vs. patients with rLVEF and mrLVEF. It is worth mentioning that AF was more common in these patients with pLVEF, although the AF was associated with an increased risk of stroke or transient ischemic attack, regardless of LVEF status. 17 Conclusion In patients with heart failure and without a clinical diagnosis of stroke, the reduced and mid-range left ventricular ejection fractions contributed to the occurrence of territorial and lacunar silent cerebral infarction, respectively. In cases of preserved left ventricular ejection fraction, there was no prevalence of silent cerebral infarction; reduced left ventricular ejection fraction and diabetes mellitus were associated with embolic cerebral infarction, and the lower the left ventricular ejection fraction, the higher the prevalence of silent cerebral infarction. Further studies are required to elucidate the mechanisms of silent cerebral infarction in the left ventricular ejection fraction groups. 420