Análise do metabolismo do ferro na cardiopatia chagásica crônica

Abstract

The Chagas disease, caused by Trypanosoma cruzi (T.cruzi), was discovered and described by the Brazilian doctor, Carlos Chagas, in 1909 (CHAGAS, 1909). Unfortunately, even after having completed a century since its original description, it continues to have a terrible impact on humanity. Chagas heart disease and its consequent heart failure does not seem to differ from other forms of cardiomyopathies when looking at its pathophysiology. However, we believe that the results of studiesrelated to the prognostics and iron metabolism in heart failure can be extrapolated to those patients diagnosed with Chagasic cardiomyopathy. In this cross-sectional observational study, 80 consecutive patients with Chagas disease (Chd) were selected, of which 40 had Chronic Chagasic Cardiomyopathy (CCC) and 40 had an undetermined form. Another 40 patients had a non-Chagistic cardiomyopathy (NCh). The objectivewas to verify if the iron kinetic indicators have a relationship with the morbidity and etiology of Chagasic cardiomyopathy compared with the non-Chagasic cardiomyopathy. The selection was done at the renowned Chagas treatment outpatient unit of the Hospital das Clinicas of the Federal University of Minas Gerais (UFMG) and for the reference patients, at the Bias Fortes Cardiology outpatient unit. The selection criteria used was the presence of a left ventricular diastolic diameter (LVD) greater than 55 mm or 2.7 cm/m2 and at least one of the following: left ventricular ejection fraction (LVEF) less than 55% (Simpson, modified) and/or a function deficit of the left ventricular segment in the CCC and NCh groups, along with a serology that showed positive for T.cruzi for the CCC and IND groups. This latter criteria was in accordance with the ones for the classification of the undetermined form. Patients with any otherco-morbidity possibilities were excluded in order to avoid confusion in the analyses of the data. In group CCC, 50% were male, in the IND one, 52.2%, and in the NCh one, 12.5%. The average age was 50.98 ± 5.88 for CCC, 49.68 ± 5.28 for IND and 49.20±10.09 for NCh. Clinically, there were functionally distributed according to NYHA: 30% in functional class I, 37.5% in II, 20% in III, and 12.5% in IV for the CCC group; 100% of the IND group were in I, and 80% of the NCh were in I, while 15% were in II, 2.5% in III and 2.5% in IV. The iron kinetic indicators correlated negativelywith the left ventricular diastolic diameter (LVD) transferrin saturation index TSAT (r=-0.949, p=0.0035), FeSe (r=-0.959, p=0.0041), ferritin (r=-0.974, p=0.0026) and positively with the total iron bonding capacity TIBC (r=0.965, p=0.0035). The relationship E/e negatively correlated with TSAT (r=-0.970, p=0.0030) and FeSe (r=-0.998, p=0.0002) and positive with TIBC (r=0.949, p=0.0051). In addition, LVEF also positively correlated with TSA (r=0.894, p=0.0041), FeSe (r=0.958, p=0.0042) andferritin (r=0.949, p=0.0051), while TIBC correlated negatively (r=-0.894, p=0.0041) in the IND group. In the correlation analysis, the iron kinetic indicators correlated negatively with LVD (r=-0.950, p<0.05), TSAT (r=-0.894, p<0.004), TIBC (r=-0.983, p<0.0017) and ferritin (r=-0.997, p<0.003) in the CCC group, while the E/e relationship correlated negatively with STI (r=-0.918, p=0.0010) and FeSe (r=-0.990, p=0.0028),positively in TIBC (r=0.998, p=0.0020) and ferritin (r=0.975, p=0.0005) in the CCC group. In the correlation analysis for the NCh group, the LVD correlated negatively with TSAT (r=-0.895, p=0.0040), FeSe (r=-0.947, p=0.0015) and ferritin (r=-0.975, p=0.0005), and positively with TIBC (r=0.893, p=0.0042), while the E/e relationship correlated negatively with TSAT (r=-0.949, p=0.0024) and serum ferritin (r=-0.976, p=0.0024), and positively with FeSe (r=0.962, p=0.0009) and TIBC (r=0.962, p=0.0009). In addition, LVEF correlated negatively with serum iron (r=-0.953, p=0.0047) and ferritin (r=0.976, p=0.0024) and positively with TIBC (r=0.960, p=0.0047) in the same group. (T.cruzi), 41 males (34%) with ages varying between 26 and 56 years of age (average of 49.95±7.42) grouped together as non-Chagasic cardiomyopathy (CCC). The NCh group included 40 patients between the ages of 39 and 59.23 (average of 49.20±10.09), a majority of whom were in the functional classes Iand II of the New York Heart Association (NYHA). Consecutive selection was done among patients attended at the renowned Chagas treatment outpatient unit of the Hospital das Clinicas of the Federal University of Minas Gerais (UFMG) and for the reference patients, at the Bias Fortes Cardiology outpatient unit. The selection criteria used was the presence of a left ventricular diastolic diameter (LVD) greater than 55 mm or 2.7 cm/m2. Patients with any other co-morbidity possibilities were excluded in order to avoid confusion in the analyses of the data. The primary objective was to verify if the iron kinetic indicators have a relationship with the morbidity and etiology of Chagasic cardiomyopathy compared with the non-Chagasic cardiomyopathy. As a secondary objective, we analyzed the FeSe levels, TIBC, TSAT and ferritin. We observed the statistical difference (ANOVA-one Way) for FeSe among the CCC (93.15 ± 36.53),IND (125.30 ± 22.79) and NCh (114.77 ± 18.90) groups, as well as the transferrin saturation index (STI) in the CCC (29.48 ± 6.59), IND (30.95±7.06) and NCh (39.70 ±7.54). Also analyzed was the total iron bonding capacity for iron (TIBC) in the CCC (297.30 ± 36.46), in the IND (196.52 ± 56.95) and in the NCh (275.18 ± 33.48) groups, together with the ferritin in the CCC (134.55, 1.56-42.36), in the IND (156.25, 1.72 42.20) and in the NCh (112.95, 2.88-42.66) groups. It was also verified that the FeSe (IC% 95% 1.00-1.04; p<0.014), TSAT (IC 95% 1.02-1.22; p<0.012) and gender (IC 95% 1.07-14.43 p=0.038) associated independently of the degree of ventricular dysfunction in the Chagasic cardiomyopathy according the multivariable proportional risk model, Hard ration (HR). Therefore, it can be concluded that patients with CCCdemonstrated to have a greater alteration in the iron metabolism compared to the undetermined form and other forms of cardiomyopathies correlated with the degree of ventricular dysfunction and cardiomyopathy remodeling.Keywords: Chagasic cardiomyopathy, iron metabolism, ejection fraction, left ventricular diastolic diameter