ABC | Volume 114, Nº4, April 2020

Original Article Souza et al. Nocturnal BP fall in acute Chagas disease Arq Bras Cardiol. 2020; 114(4):711-715 Methods This was a single-center study conducted in a university hospital. ABPM was performed in 54 patients (convenience sample) with orally transmitted ACD, seen in an outpatient clinic of infectious and parasitic diseases and 54 age- and sex- matched healthy controls. This control group was used aiming at evaluating the prevalence of lack of nocturnal BP fall in individuals without comorbidities, since this variable has not been investigated in the Brazilian population. The healthy controls had no complaints or history of any disease, had a normal clinical examination and were not taking any medication at baseline. All participants or their legal representatives signed an informed consent form. The ABPM was carried out using a Dyna-MAPA ® device. Inclusion criteria were patients attending the outpatient clinic with a diagnosis of ACD confirmed by a positive parasitological and/or serological test, in addition to meeting the epidemiological criteria established by the Brazilian Ministry of Health’s protocol, available at: http://portalms. saude.gov.br/saude-de-a-z/doenca-de-chagas. Exclusion criteria were presence of diabetes mellitus, neurological diseases, arterial hypertension, cardiovascular disease, ongoing infection, hematological disease such as anemia, conditions that may affect renal function, thyroid disease or other important systemic changes, use of illicit drugs, pregnancy and alcoholism. In the control group, ABPM was performed with normotensive individuals. The test was ordered as a routine test (health check-up) rather than for suspected hypertension. Individuals with any type of cardiac disease were not included. The following ABPM parameters were assessed: 24-hour systolic (SBP) and diastolic BP (SBP), BP during sleep and awake states, and BP fall during sleep. Physiological fall in SBP and DBP was considered as a reduction ≥ 10% in mean BP registered during sleep. The awake period was considered the period from8 to 20 o’clock, whereas the sleep-period time from 20 to 8 o’clock on the day after, following the 2011 Brazilian Guidelines on ABPM and home blood pressure monitoring. 7 The study was approved by the ethics committee of the Hospital Universitário João de Barros Barreto (CAAE 01278918.4.00000017). Statistical analysis The chi-square test was used to compare individuals that did not show a nocturnal BP fall between patients and control group. A p<0.05 was set as statistically significant. Categorical variables were presented as frequency, absolute numbers and percentage. Normally distributed variables were presented as mean and standard deviation. The Kolmogorov-Smirnov test and the histogram-normality test were used, and measurement of asymmetry and kurtosis was performed. The SPSS 23.0 software for Windows (IBM SPSS Statistics para Windows version 23.0, launched in 2015, Armonk, NY: IBM Corp). Results In the total of 54 patients with acute infection with T. cruzi , mean age was 36.2 ±10.4 years, 30 were women (mean age 34.7 ± 19.0 years) and 24 men (mean age 38.3 ± 19.7 years). The ABPM showed that 40 patients (74.0%) did not show nocturnal fall in SBP, and 29 (53.7%) did not show nocturnal fall in DBP. This occurred concomitantly in 29 (53.7%) patients; seven (12.9%) showed nocturnal increase in SBP and 10 (18.5%) in DBP. No statistically significant difference was found in the mean 24-hour SBP and mean 24-hour DBP during sleep and awake states between patients with ACD and control group (Table 1). Significant differences were found between the groups for nocturnal fall in SBP and DBP in both sexes. Discussion Discussion Changes in autonomic nervous system are well characterized in chronic Chagas disease, with neuron loss and lesion in the parasympathetic pathway and increased sympathetic activity. Studies on patients with the indeterminate form of Chagas disease have shown a predominance of parasympathetic activity in these patients, which was correlated with autonomic dysfunction. 9 Results of an interesting study indicated a relationship between changes in autonomic modulation and endothelial function in patients with ACD. 10 Lesions in the central nervous system were found in anatomopathological studies in ACD patients, described as distant systemic lesions caused by Table 1 – Mean values of 24-hour blood pressure during sleep and awake states in 54 normotensive patients with acute Chagas disease and 54 normotensive individuals without Chagas disease (controls) Controls Acute Chagas disease 24h awake state sleep 24h awake state sleep Mean 114.1±10.3 117.3±10.4 100.9±10.0 111.0±10.6 112.7±10.5 105.1±11.7 SBP mmHg Mean 68.9±7.6 71.3±8.1 59.2±7.5 66.9±7.0 68.3±7.2 62.2±8.1 DBP mmHg Data expressed as mean and standard deviation; SBP: systolic blood pressure; DBP: diastolic blood pressure; ACD: acute Chagas disease 712