Optimized procedures for testing plasma metanephrines in patients on hemodialysis.

Diagnosis of pheochromocytomas and paragangliomas in patients receiving hemodialysis is troublesome. The aim of the study was to establish optimal conditions for blood sampling for mass spectrometric measurements of normetanephrine, metanephrine and 3-methoxytyramine in patients on hemodialysis and specific reference intervals for plasma metanephrines under the most optimal sampling conditions. Blood was sampled before and near the end of dialysis, including different sampling sites in 170 patients on hemodialysis. Plasma normetanephrine concentrations were lower (P < 0.0001) and metanephrine concentrations higher (P < 0.0001) in shunt than in venous blood, with no differences for 3-methoxytyramine. Normetanephrine, metanephrine and 3-methoxytyramine concentrations in shunt and venous blood were lower (P < 0.0001) near the end than before hemodialysis. Upper cut-offs for normetanephrine were 34% lower when the blood was drawn from the shunt and near the end of hemodialysis compared to blood drawn before hemodialysis. This study establishes optimal sampling conditions using blood from the dialysis shunt near the end of hemodialysis with optimal reference intervals for plasma metanephrines for the diagnosis of pheochromocytomas/paragangliomas among patients on hemodialysis.

Systematic and Multidisciplinary Evaluation of Fibromuscular Dysplasia Patients Reveals High Prevalence of Previously Undetected Fibromuscular Dysplasia Lesions and Affects Clinical Decisions: The ARCADIA-POL Study.

Fibromuscular dysplasia (FMD), regarded as a generalized vascular disease, may affect all vascular beds and may result in arterial stenosis, occlusion, aneurysm, or dissection. It has been proposed to systematically evaluate all vascular beds in patients with FMD, regardless of initial FMD involvement. However, the impact of this approach on clinical decisions and on management is unknown. Within the prospective ARCADIA-POL study (Assessment of Renal and Cervical Artery Dysplasia-Poland), we evaluated 232 patients with FMD lesions confirmed in at least one vascular bed, out of 343 patients included in the registry. All patients underwent a detailed clinical evaluation including computed tomography angiography of intracranial and cervical arteries, as well as computed tomography angiography of the abdominal aorta, its branches, and upper and lower extremity arteries. In the study group, FMD lesions were most frequently found in renal arteries (87.5%). FMD was also found in cerebrovascular (24.6%), mesenteric (13.8%), and upper (3.0%) and lower extremity (9.9 %) arteries. Newly diagnosed FMD lesions were found in 34.1% of the patients, and previously undetected vascular complications were found in 25% of the patients. Among all FMD patients included in the study, one out of every 4 evaluated patients qualified for interventional treatment due to newly diagnosed FMD lesions or vascular complications. The ARCADIA-POL study shows for the first time that the systematic and multidisciplinary evaluation of patients with FMD based on a whole-body computed tomography angiography scan has an impact on their clinical management. This proved the necessity of the systematic evaluation of all vascular beds in patients with FMD, regardless of initial FMD involvement.

Impact of 123I-MIBG Scintigraphy on Clinical Decision-Making in Pheochromocytoma and Paraganglioma.

CONTEXT: Cross-sectional imaging with CT or MRI is regarded as a first-choice modality for tumor localization in patients with pheochromocytoma and paraganglioma (PPGL). 123I-labeled metaiodobenzylguanidine (123I-MIBG) is widely used for functional imaging but the added diagnostic value is controversial. OBJECTIVE: To establish the virtual impact of adding 123I-MIBG scintigraphy to CT or MRI on diagnosis and treatment of PPGL. DESIGN: International multicenter retrospective study. INTERVENTION: None. PATIENTS: Two hundred thirty-six unilateral adrenal, 18 bilateral adrenal, 48 unifocal extra-adrenal, 12 multifocal, and 26 metastatic PPGL. MAIN OUTCOME MEASURES: Patients underwent both anatomical imaging (CT and/or MRI) and 123I-MIBG scintigraphy. Local imaging reports were analyzed centrally by two independent observers who were blinded to the diagnosis. Imaging-based diagnoses determined by CT/MRI only, 123I-MIBG only, and CT/MRI combined with 123I-MIBG scintigraphy were compared with the correct diagnoses. RESULTS: The rates of correct imaging-based diagnoses determined by CT/MRI only versus CT/MRI plus 123I-MIBG scintigraphy were similar: 89.4 versus 88.8%, respectively (P = 0.50). Adding 123I-MIBG scintigraphy to CT/MRI resulted in a correct change in the imaging-based diagnosis and ensuing virtual treatment in four cases (1.2%: two metastatic instead of nonmetastatic, one multifocal instead of single, one unilateral instead of bilateral adrenal) at the cost of an incorrect change in seven cases (2.1%: four metastatic instead of nonmetastatic, two multifocal instead of unifocal and one bilateral instead of unilateral adrenal). CONCLUSIONS: For the initial localization of PPGL, the addition of 123I-MIBG scintigraphy to CT/MRI rarely improves the diagnostic accuracy at the cost of incorrect interpretation in others, even when 123I-MIBG scintigraphy is restricted to patients who are at risk for metastatic disease. In this setting, the impact of 123I-MIBG scintigraphy on clinical decision-making appears very limited.

High incidence and clinical characteristics of fibromuscular dysplasia in patients with spontaneous cervical artery dissection: The ARCADIA-POL study.

The association between fibromuscular dysplasia (FMD) and spontaneous cervical artery dissection (SCeAD) has been recognized, but the available evidence on this relationship is scant. Therefore, the main goal of our study was to systematically evaluate FMD frequency, clinical characteristics and vascular bed involvement in patients with SCeAD. Among 230 patients referred to the ARCADIA-POL study, 43 patients (mean age 44.1 ± 8.9 years; 15 men and 28 women) with SCeAD were referred. Also, 135 patients with FMD were compared to patients with and without SCeAD. Patients underwent: ambulatory blood pressure measurements, biochemical evaluation, echocardiographic examination, and whole body computed tomographic angiography. FMD changes were found in 39.5% of patients with SCeAD. There were no differences in clinical characteristics between patients with SCeAD and FMD and those without FMD, except for a tendency towards a higher female ratio in SCeAD patients with FMD. There were no differences in other parameters describing target organ and SCeAD characteristics. Patients with SCeAD and FMD compared to those without SCeAD were characterized by a lower frequency of hypertension and a higher frequency of hyperlipidemia and history of contraceptive hormone use. Our study indicates a high incidence (39.5%) of FMD in subjects with SCeAD. Since there are no distinctive discriminating factors between patients with SCeAD and FMD and those without FMD, FMD should be suspected in all patients with SCeAD.

Echocardiographic assessment of left ventricular morphology and function in patients with fibromuscular dysplasia: the ARCADIA-POL study.

OBJECTIVE: To provide a comprehensive assessment of left ventricle (LV) structure, and function and to detect alterations in cardiac properties in relationship to presence, subtypes and extent of fibromuscular dysplasia (FMD). METHODS: We studied 144 patients with FMD. The control group consisted of 50 matched individuals. Office and ambulatory blood pressure levels were evaluated. Echocardiography was employed to assess: left ventricular mass index (LVMI), systolic function including speckle tracking echocardiography and diastolic function assessed by mitral flow and tissue Doppler imaging. RESULTS: There were no differences in LV morphology and function between patients with FMD and the control group. Among 128 patients with renal FMD, there were no differences in LVMI and LV systolic function between patients with unifocal and multifocal FMD. The patients with multifocal FMD were characterized by lower early diastolic velocity (e') as compared with unifocal FMD and control groups. However, in a multivariate regression model, e' was not independently correlated with FMD. There were no associations between echocardiographic indexes and vascular involvement of FMD. Also, there were no differences in LV morphology and function in patients with significant renal artery stenosis (RAS) compared with patients with history of significant RAS and patients with nonsignificant RAS. CONCLUSION: Our study in contrast to those with atherosclerotic RAS, did not show differences in LV morphology and function between FMD patients and matched controls. Although FMD can result in hypertension and serious vascular complications, there is no proof that it can alter LV regardless of FMD type and its extent.

Plasma methoxytyramine: clinical utility with metanephrines for diagnosis of pheochromocytoma and paraganglioma.

CONTEXT: Measurements of plasma methoxytyramine, the O-methylated dopamine metabolite, are useful for detecting rare dopamine-producing pheochromocytomas and paragangliomas (PPGLs) and head and neck paragangliomas (HNPGLs), but utility for screening beyond that achieved using standard measurements of normetanephrine and metanephrine is unclear. OBJECTIVE: Evaluation of the additional utility of methoxytyramine compared to plasma normetanephrine and metanephrine for diagnosis of PPGLs and HNPGLs. DESIGN: Comparative prospective study. METHODS: Comparison of mass spectrometric-based measurements of plasma methoxytyramine, normetanephrine and metanephrine in 1963 patients tested for PPGLs at six tertiary medical centers according to reference intervals verified in 423 normotensive and hypertensive volunteers. RESULTS: Of the screened patients, 213 had PPGLs and 38 HNPGLs. Using an upper cut-off of 0.10 nmol/L for methoxytyramine, 0.45 nmol/L for metanephrine and age-specific upper cut-offs for normetanephrine, diagnostic sensitivity with the addition of methoxytyramine increased from 97.2% to 98.6% for patients with PPGLs and from 22.1% to 50.0% for patients with HNPGLs, with a small decrease in specificity from 95.9% to 95.1%. Addition of methoxytyramine did not significantly alter areas under receiver operating characteristic curves for patients with PPGLs (0.984 vs 0.991), but did increase (P < 0.05) areas for patients with HNPGLs (0.627 vs 0.801). Addition of methoxytyramine also increased the proportion of patients with PPGLs who showed highly positive predictive elevations of multiple metabolites (70.9% vs 49.3%). CONCLUSIONS: While the benefit of additional measurements of plasma methoxytyramine for the detection of PPGLs is modest, the measurements do assist with positive confirmation of disease and are useful for the detection of HNPGLs.