Prolonged dipyridamole administration reduces myocardial perfusion defects in experimental chronic Chagas cardiomyopathy.

BACKGROUND: Myocardial perfusion defects (MPD) due to coronary microvascular dysfunction is frequent in chronic Chagas cardiomyopathy (CCC) and may be involved with development of myocardial damage. We investigated whether MPD precedes left ventricular systolic dysfunction and tested the hypothesis that prolonged use of dipyridamole (DIPY) could reduce MPD in an experimental model of CCC in hamsters. METHODS AND RESULTS: We investigated female hamsters 6-months after T. cruzi infection (baseline condition) and control animals, divided into T. cruzi-infected animals treated with DIPY (CH + DIPY) or placebo (CH + PLB); and uninfected animals treated with DIPY (CO + DIPY) or placebo (CO + PLB). The animals were submitted to echocardiogram and rest SPECT-Sestamibi-Tc99m myocardial perfusion scintigraphy. Next, the animals were treated with DIPY (4 mg/kg bid, intraperitoneal) or saline for 30 days, and reevaluated with the same imaging methods. At baseline, the CH + PLB and CH + DIPY groups showed larger areas of perfusion defect (13.2 ± 13.2% and 17.3 ± 13.2%, respectively) compared with CO + PLB and CO + DIPY (3.8 ± 2.2% e 3.5 ± 2.7%, respectively), P < .05. After treatment, we observed: reduction of perfusion defects only in the CH + DIPY group (17.3 ± 13.2% to 6.8 ± 7.6%, P = .001) and reduction of LVEF in CH + DIPY and CH + PLB groups (from 65.3 ± 9.0% to 53.6 ± 6.9% and from 69.3 ± 5.0% to 54.4 ± 8.6%, respectively, P < .001). Quantitative histology revealed greater extents of inflammation and interstitial fibrosis in both Chagas groups, compared with control group (P < .001), but no difference between Chagas groups (P > .05). CONCLUSIONS: The prolonged use of DIPY in this experimental model of CCC has reduced the rest myocardial perfusion defects, supporting the notion that those areas correspond to viable hypoperfused myocardium.

Prospective analysis of myocardial strain through the evolution of Chagas disease in the hamster animal model.

Speckle tracking echocardiography (STE) enables early diagnosis of myocardial damage by evaluating myocardial strain. We aimed to study sequential changes in structural and ventricular functional parameters during Chagas disease (CD) natural history in an animal model. 37 Syrian hamsters were inoculated intraperitoneally with Trypanosoma cruzi (Chagas) and 20 with saline (Control). Echocardiography was performed before the infection (baseline), at 1 month (acute phase), 4, 6, and 8 months (chronic phase) using Vevo 2100 (Fujifilm Inc.) ultrasound system. Left ventricular end-diastolic diameter, Left ventricular end-systolic diameter (LVESD), Left ventricular ejection fraction (LVEF), Global longitudinal (GLS), circumferential (GCS) and radial (GRS) strain were evaluated. Tricuspid annular plane systolic excursion (TAPSE) was used to assess right ventricular function. At 8 months, animals were euthanized and LV myocardial samples were analyzed for quantitation of inflammation and fibrosis. LVEF decreased over time in Chagas group and a difference from Control was detected at 6 months (p-value of groups#time interaction = 0.005). There was a pronounced decrease in GLS, GCS and TAPSE in Chagas group (p-value of groups#time interaction = 0.003 for GLS, < 0.001 for GCS and < 0.009 for TAPSE vs Control) since the first month. LVESD, LVEF and GLS were significantly correlated to the number of inflammatory cells (r = 0.41, p = 0.046; r = - 0.42, p = 0.042; r = 0.41, p = 0.047) but not to fibrosis. In the Syrian hamster model of CD STE parameters (GLS and GCS) showed an early decrease. Changes in LVEF, LVESD, and GLS were correlated to myocardial inflammation but not to fibrosis.

Seguimento pós-operatório em longo prazo de pacientes submetidos à cirurgia valvar / Long term follow up of patients undergoing valvular cardiac surgery

Fundamentos: A valva nativa pode ser substituída por uma prótese mecânica ou biológica e a escolha do tipo de substituto valvar é passível de discussão, pois implica morbimortalidade dos pacientes operados. Objetivo: Comparar a evolução dos pacientes que receberam próteses biológicas e mecânicas. Métodos: Estudo retrospectivo realizado em prontuários de pacientes submetidos à primeira cirurgia de troca de valva (mitral e/ou aórtica), no período de 1995 a 2000, em hospital terciário da rede pública. Foram selecionados 303 pacientes: 173 constituíram o grupo com prótese mecânica. As variáveis analisadas foram sexo, idade na época da cirurgia, comorbidades, tipo de cirurgia realizada, fração de ejeção ventricular no pré-operatório e no pós-operatório, ritmo cardíaco antes e pós-procedimento e desfechos: óbito, reoperação, acidente vascular encefálico (AVE), e endocardite infecciosa. Resultados: O tempo médio de seguimento foi 10 anos. A mortalidade tardia foi 3,46% (bioprótese) e 5,38% (mecânica), p=0,568. A reoperação foi maior no grupo bioprótese (43,4%) vs. grupo prótese mecânica (4,6%) - OR=15,83 (IC 95% 6,61-7,85; p>0,001). A prevalência de AVE foi semelhante (11% - bioprótese vs.9,5% - prótese mecânica, p=0,561), assim como a prevalência de endocardite (11,6% - bioprótese vs. 6,2% - prótese mecânica, p=0,115). Conclusões: A mortalidade, a prevalência de AVE e a endocardite foram estatisticamente semelhantes entre os grupos (prótese biológica e prótese mecânica) e o número de reoperações foi significativamente maior no grupo com bioprótese, tanto em posição mitral como em posição aórtica.

Background: The native valve may be replaced by a mechanical or biological prosthesis, with this choice often open to discussion, as it raises morbidity and mortality issues for operated patients. Objective: To compare the progress of patients receiving biological and mechanical prostheses. Methods: Retrospective study of the medical records of patients undergoing first valve replacements (aortic and/or mitral), from 1995 to 2000 at a tertiary hospital in the National Health network. Of the 303 records selected, 173 constituted the biological group and 130 the mechanical prosthesis group. The variables analyzed included gender, age when operated, comorbidities, type of surgery, ventricular ejection fraction and cardiac rhythm before and after surgery, and outcones: death, reoperation, stroke and infective endocarditis. Results: The median follow-up time was 10 years, with delayed mortality at 3.46% (bio-prothesis) and 5.38% (mechanical), p=0.568. There were more reoperations in the bio-prosthesis group (43,3%) than in the mechanical group (4.6%), with and OR of 15.83 (CI 95% 6.61 - 7.85; p<0.001). The stroke rate was similar (11% for bio-prosthesis vs 8.5% mechanical) p=0.561, with endocarditis at 11.6% for bio-prosthesis vs 6.2% mechanical (p=0.115). Conclusions: The mortality, stroke and endocarditis rates were statistically similar between the groups, but with significantly more reoperations in the mitral and aortic bio-prosthesis groups.

Síndrome coronariana aguda no idoso: diagnóstico e tratamento / Acute coronary syndrome in the elderly: diagnosis and treatment

As doenças cardiovasculares representam um importante problema de saúde pública em todo o mundo, visto que constituem uma das principais causas de morbidade e mortalidade, além de apresentarem altos custos em assistência médica. A incidência dessas doenças na população aumenta dramaticamente com o envelhecimento...