Aortic stenosis concomitant with microscopic polyangiitis: a challenge in medical reasoning and thinking

Microscopic polyangiitis (MPA) is part of the anti-neutrophil cytoplasmic antibodies (ANCA)-related vasculitis, which usually presents as renal pulmonary syndrome. It is defined as a pauci-immune necrotizing small vessel vasculitis, which usually affects the kidneys, followed by the lungs. It also presents systemic symptoms. The etiology of MPA is still unclear, but evidence reinforces the autoimmune mechanisms as the main etiopathogenic factor. Aortic valve stenosis (AS) is not an uncommon disease whose etiology varies according to geographical differences and the patient’s age. The natural history of AS begins with a prolonged asymptomatic period, but when symptomatic, respiratory failure is one of its main clinical presentations. The authors present the case of a 55-year-old woman who was admitted with the diagnosis of renal failure, anemia, and a cardiac murmur. The patient had been recently diagnosed with pneumonia. During hospitalization, diagnostic workup disclosed a normal kidney size as well as parenchymal thickness. A renal biopsy was undertaken but the specimen was exiguous, showing 4 sclerotic glomeruli and 1 glomerulus with crescentic glomerulonephritis. The search for ANCA was positive. The investigation of the cardiac murmur disclosed AS. The patient, on hemodialysis, presented episodes of respiratory failure, which was interpreted as acute pulmonary edema, but a suspicion of ANCA-related pulmonary renal syndrome was raised. However, the aortic valve replacement was prioritized. While awaiting cardiac surgery, the patient died because of respiratory insufficiency. Autopsy findings concluded that MPA with pulmonary hemorrhage due to vasculitis was the immediate cause of death. Although AS was present at autopsy and classified as moderate/severe, this lesion was a bystander in the process of this patient’s end of life, demonstrating the value of autopsy for medical learning and reasoning purposes

Diferentes padrões de remodelamento aterosclerótico na aorta torácica e abdminal

PURPOSE: To investigate the relationship between the vascular diameter and the extent and histologic characteristics of atherosclerosis in the thoracic and abdominal aortas of patients who died of atherosclerotic disease. METHOD: We measured the vascular diameter and evaluated the percentage atrophy of the medial layer of the thoracic and abdominal aortas of 19 patients who died due to atherosclerotic disease. The extent of plaques, calcification, ulceration, thrombosis, and the amount of fat in the plaques were evaluated semiquantitatively. RESULTS: Atherosclerosis was more severe in the abdominal than the thoracic aorta as indicated by the higher sum of the macroscopic scores (P = .02) and the higher percentage atrophy of the medial layer (P < .001). The diameter of the thoracic, but not of the abdominal aorta, correlated with age (r = 0.56; P = .01), plaque score (r = 0.59; P = .008), calcification score (r = 0.749; P < .001), and fat score (r = 0.48; P = .04). Multiple linear regression showed that age (P = .06) and calcification score (P = .001) were the parameters with the strongest association to thoracic aorta diameter. CONCLUSION: There are some differences regarding atherosclerosis in the thoracic compared to the abdominal aorta. Progressive thoracic aorta atherosclerosis is associated with fat deposition in the plaques, inducing arterial dilation. In the abdominal aorta, atherosclerosis can either have a similar evolution or be associated with less fat deposition in the arterial wall, which would result in more rigidity, hindering compensatory arterial enlargement.OBJETIVO: Estabelecer relações entre o diâmetro vascular e a intensidade e características histológicas da aterosclerose, nos segmentos torácico e abdominal da aorta. MÉTODO: Foi medido o diâmetro vascular e avaliada a porcentagem de atrofia da camada média da aorta torácica e abdominal de 19 pacientes que faleceram devido a doença aterosclerótica. A presença de placas, calcificação, ulceração, trombose e a quantidade de gordura das placas foi avaliada, semiquantitativamente, nas mesmas regiões. RESULTADOS: A aterosclerose foi mais intensa na aorta abdominal que na torácica, conforme demonstrado pela maior soma dos escores macroscópicos (p = 0,02) e pela maior porcentagem de atrofia da camada média (p < 0,001). O diâmetro da aorta torácica, porém não o da abdominal apresentou correlação positiva com a idade (r = 0,56; p = 0,01), escore de placa (r = 0,59; p = 0,008), escore de calcificação (r = 0,749; p < 0,001) e escore de gordura (r = 0,48; p = 0,04). O modelo de regressão linear múltipla evidenciou que as variáveis mais associadas ao diâmetro da aorta torácica foram a idade (p = 0,06) e o escore de calcificação (p = 0,001). CONCLUSÃO: A aterosclerose apresenta algumas características distintas nos segmentos torácico e abdominal da aorta. A progressão da aterosclerose na aorta torácica associa-se à deposição de gordura nas placas, ocorrendo dilatação arterial. Na aorta abdominal a aterosclerose pode apresentar evolução semelhante ou estar relacionada à menor deposição de gordura na parede arterial, que se tornaria mais rígida, impedindo a dilatação compensatória