Base racional e plano de estudo prospectivo para avaliar o efeito de terapêutica antiplaquetária e vasodilatadora microcirculatória em pacientes com cardiopatia chagásica crônica e distúrbios microvasculares coronários

Abstract

Background: Studies on Trypanosoma cruzi infections and histopathologic studies in individuals with Chagas disease suggest that ischaemia plays a role in the pathogenesis of myocardial lesions in the chronic phase of the disease. These ischaemic disorders are caused by microcirculatory deregulation. Atypical angina is a common symptom in patients in the chronic phase of Chagas disease. In a large number of patients, despite the absence of significant angiographic coronary obstructions, the occurrence of perfusion abnormalities is documented by myocardial scintigraphy during stress, which is reversible after rest. Methods: This will be a single-centre, prospective, single cohort study with a therapeutic intervention followed by a late quantitative re-evaluation of myocardial perfusion defects initially detected in patients with Chagas disease and angiographically normal coronary arte ries. Myocardial perfusion single-photon emission computed tomography (SPECT) will be performed before and 90 days after therapeutic intervention using Technetium ( 99m Tc) sestamibi as a radiotracer and physical stress or vasodilation stimulation with dipyridamole. Therapeutic intervention will consist of acetylsalicylic acid (single daily dose of 100 mg) with verapamil (80 mg b.i.d.; a total daily dose of 160 mg). The primary endpoint of the study is a > 50% reduction of the area of ischaemic myocardium calculated by the polar scintigraphic map. Conclusions: This will be the first study of a therapeutic approach to attenuate or reverse ischaemic

Pathogenesis of chronic Chagas cardiomyopathy: the role of coronary microvascular derangements

“…One such study is currently ongoing, with the primary objective of testing the hypothesis that the prolonged administration of verapamil and acetylsalicylic acid to Chagas patients with normal epicardial coronary arteries, chest pain and reversible ischemic perfusion defects at baseline examination will lead to a reduction in the extent and intensity of the perfusion abnormalities and a mitigation of the angina-like symptoms 61 .…”

Efeitos de terapêutica antiplaquetária e vasodilatadora microcirculatória sobre os distúrbios microvasculares e sintomas anginosos que ocorrem na cardiopatia crônica da doença de Chagas. Estudo prospectivo com coronariografia e cintilografia miocárdica de perfusão

“…Durante a fase de planejamento do estudo, o cálculo amostral baseou-se na avaliação de área total de defeito perfusional quantificada em mapa polar pelo software específico de equipamento anteriormente disponível na Instituição (Sopha Medical Vision -General Eletric), conforme detalhado em publicação prévia sobre o desenho deste estudo (Macedo et al, 2012). Esta metodologia de avaliação cintilográfica fora utilizada em estudos anteriores conduzidos por nosso grupo (Hiss et al, 2009) (Miranda et al, 2011;Gadioli et al, 2018).…”