Glomerular filtration rate measured by 51Cr-EDTA clearance: evaluation of captopril-induced changes in hypertensive patients with and without renal artery stenosis

INTRODUCTION: Renal artery stenosis can lead to renovascular hypertension; however, the detection of stenosis alone does not guarantee the presence of renovascular hypertension. Renovascular hypertension depends on activation of the renin-angiotensin system, which can be detected by functional tests such as captopril renal scintigraphy. A method that allows direct measurement of the baseline and post-captopril glomerular filtration rate using chromium-51 labeled ethylenediamine tetraacetic acid (51Cr-EDTA) could add valuable information to the investigation of hypertensive patients with renal artery stenosis. The purposes of this study were to create a protocol to measure the baseline and post-captopril glomerular filtration rate using 51Cr-EDTA, and to verify whether changes in the glomerular filtration rate permit differentiation between hypertensive patients with and without renal artery stenosis. METHODS: This prospective study included 41 consecutive patients with poorly controlled severe hypertension. All patients had undergone a radiological investigation of renal artery stenosis within the month prior to their inclusion. The patients were divided into two groups: patients with (n=21) and without renal artery stenosis, (n=20). In vitro glomerular filtration rate analysis (51Cr-EDTA) and 99mTc-DMSA scintigraphy were performed before and after captopril administration in all patients. RESULTS: The mean baseline glomerular filtration rate was 48.6±21.8 ml/kg/1.73 m² in the group wuth renal artery stenosis, which was significantly lower than the GFR of 65.1±28.7 ml/kg/1.73m² in the group without renal artery stenosis (p=0.04). Captopril induced a significant reduction of the glomerular filtration rate in the group with renal artery stenosis (to 32.6±14.8 ml/kg/1.73m², p=0.001) and an insignificant change in the group without RAS (to 62.2±23.6 ml/kg/1.73m², p=0.68). Scintigraphy with technetium-99m dimercapto-succinic acid (DMSA) did...

Medida da filtração glomerular determinada por EDTA-51Cr antes e após a administração de captopril: avaliação de pacientes hipertensos com ou sem estenose de artéria renal / Glomerular filtration rate measured by 51Cr-EDTA clearance before and after captopril administration: evaluation of hypertensive patients with and without renal artery stenosis

INTRODUÇÃO: A hipertensão renovascular (HRV) decorrente da estenose de artéria renal (EAR) é uma patologia potencialmente curável, mas os benefícios da revascularização não são alcançados por todos porque selecionar pacientes com base nos critérios clínicos ou angiográficos pode não ser suficiente para se obter o sucesso clínico. Existe um grande interesse em se desenvolver exames para detectar a presença de EAR e avaliar seu significado funcional. OBJETIVOS: avaliar se a redução da Taxa de Filtração Glomerular (TFG) medida com EDTA-51Cr após o uso de captopril consegue diferenciar pacientes hipertensos com EAR daqueles sem estenose da artéria e avaliar se existe correlação entre as variações da TFG e a evolução de pacientes submetidos a diferentes tratamentos. MÉTODOS: Foram estudados 41 pacientes com hipertensão arterial de difícil controle que foram divididos em dois grupos: GP: 21 pacientes com EAR e GH: 20 pacientes sem EAR. Os pacientes foram submetidos à medida de TFG com EDTA-51Cr pré e após a administração do captopril. Os pacientes do GP realizaram simultaneamente cintilografia com DMSA-99mTc para avaliação da função renal diferencial. Os pacientes com estenose de artéria renal foram subdivididos de acordo com o tratamento recebido: clínico (GP-CL) ou por intervenção (GP-I). As medidas das TFGs antes e após o captopril foram comparadas entre os grupos. Foi também, investigado se a relação pré/pós captopril tinha correlação com a resposta clínica dos pacientes. RESULTADOS: a média da TFG (ml/min./1,73m2) no total de pacientes estudados, foi de 56,7±26,5 na fase pré-captopril e 47,0±24,4 após o captopril. A modificação da TFG determinada pelo captopril,foi avaliada pela relação da filtração glomerular pré/pós-captopril. A média da relação TFG pré/pós-captopril foi 1,36 ±0,54 no grupo total de pacientes e quando foi feita a comparação entre a TFG pré e pós-captopril, houve uma redução significativa (p= 0,016). O GH mostrou relação média da...

INTRODUCTION: Renovascular hypertension (RVH) resulting from renal artery stenosis (RAS) is a potential curable pathology, but the revascularization benefits are not reached among all patients because selecting patients on the basis of clinical and angiographic criteria may not be sufficient to achieve clinical success. There has been increasing interest in developing screening tests capable of accurately detecting the presence of RAS and also of evaluating its functional consequences PURPOSE: the purpose of this study was to evaluate if captopril induced changes in 51Cr-EDTA clearance could be used to differentiate between hypertensive patients with and without renal artery stenosis and to investigate if there was a correlation between these changes and patients clinical response to therapy. METHODS: 41 patients with poor-controlled severe hypertension were studied. Patients were divided into two groups: GP=patients with renal artery stenosis (n=21), and GH=patients without renal artery stenosis (n=20). They were submitted to a Glomerular Filtration Rate (GFR) measurement with EDTA-51Cr pre and post captopril administration. The GP patients were submitted simultaneously to 99mTc-DMSA scintigraphies to estimate individual renal function. GP patients were further subdivided according to the treatment strategy: optimization of clinical treatment (GP-Cl) and interventional procedures (GP-I). The GFRs before and after captopril administration were compared between the groups. It was also investigated if baseline to post-captopril GFR ratio had a correlation to clinical response of patients. RESULTS: The GFR average (ml/min./1,73m2) on the total patients, was 56,7±26,5 on pre-captopril phase and 47,0±24,4 post captopril. The GFR alteration determinated by captopril was evaluated by Baseline/post-captopril GFR ratio. Baseline/post-captopril GFR mean ratio was 1,36 in total patients and the GFR had a significant decrease after captopril administration...

Metabolic test with fluorine-18-fluorodeoxyglucose in staging and detection of residual tumor or recurrence in Hodgkin lymphoma

OBJECTIVE: The metabolic test using 18F-fluorodeoxyglucose is a useful tool for the management of patients with Hodgkin lymphoma, either for staging purposes or for the evaluation of suspicious masses that can frequently occur after treatment. The aim of the present study was to investigate the value of the 18F-fluorodeoxyglucose test performed with a dual-head coincident gamma camera (CGC-PET with fluorodeoxyglucose) for the staging and the detection of residual tumor of patients with Hodgkin lymphoma. METHODS: Thirty-eight consecutive patients were included in this retrospective study; the metabolic test comprising CGC-PET with FDG was done in 18 patients for staging work-up (Group 1), and the results were compared to conventional clinical staging procedures that included computed tomography scans and bone marrow biopsy. The remaining 20 patients were evaluated with CGC-PET with fluorodeoxyglucose due to the presence of residual masses or a new lesion (Group 2). RESULTS: The 18F-Fluorodeoxyglucose metabolic test, CGC-PET with fluorodeoxyglucose, upstaged 5 (27 percent) of the Group 1 patients and detected more lesions (45) than conventional methods of staging (33). Of the 20 patients in Group 2, 11 had positive18F-fluorodeoxyglucosetests, and a viable tumor was confirmed in 9 patients. Regarding the 9 patients with negative fluorodeoxyglucose metabolic tests, the 1-year probability of recurrence was 11.8 percent. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of the CGC-PET with fluorodeoxyglucose test were 90 percent, 80 percent, 82 percent, 89 percent, and 85 percent respectively. CONCLUSIONS: The metabolic test comprising CGC-PET with fluorodeoxyglucose had a higher diagnostic accuracy than conventional methods in the staging of Hodgkin lymphoma and thus is a valuable noninvasive tool for the diagnosis of suspicious lesions.

OBJETIVO: O estudo metabólico com 18F-fluorodeoxiglicose é uma ferramenta útil para o manejo de portadores de linfoma de Hodgkin, tanto como método auxiliar no estadiamento da doença, quanto na avaliação de massas suspeitas encontradas após tratamento. O objetivo deste estudo foi investigar o valor do estudo com 18F-fluorodeoxiglicose em gama câmara híbrida no estadiamento e na detecção de tumor residual em pacientes com linfoma de Hodgkin. MÉTODOS: Trinta e oito pacientes foram incluídos neste estudo retrospectivo, 18 foram avaliados com o estudo metabólico durante o estadiamento (Grupo 1), sendo os resultados do estudo comparados com os obtidos com o estadiamento convencional, que incluiu tomografia e biópsia de medula óssea. Os 20 pacientes restantes realizaram o estudo metabólico devido à presença de massa residual ou de nova lesão suspeita (Grupo 2). RESULTADOS: O estudo metabólico aumentou o estádio de cinco (27 por cento) dos pacientes do Grupo 1 e pôde detectar mais lesões que os métodos convencionais de estadiamento (45 lesões detectadas com 18F-fluorodeoxiglicose versus 33 lesões métodos convencionais). Nos 20 pacientes do Grupo 2, 11 foram 18F-fluorodeoxiglicose positivos e tumor viável foi confirmado em 9 pacientes. Nos 9 pacientes com estudo metabólico negativo, a probabilidade de recidiva em um ano foi de 11.8 por cento. A sensibilidade, especificidade, valor preditivo positivo, valor preditivo negativo e a acurácia do estudo metabólico foram de 90 por cento, 80 por cento, 82 por cento, 89 por cento e 85 por cento respectivamente. CONCLUSÕES: O estudo com 18F-fluorodeoxiglicose apresentou melhor acurácia que os métodos convencionais de estadiamento do Linfoma de Hodgkin e foi útil para o diagnóstico não-invasivo de lesões suspeitas.