Patients' perception of diagnostic tests in the preoperative assessment of esophageal cancer

OBJECTIVE

Defining an optimal staging strategy requires an evaluation of the effectiveness and costs of diagnostic tests and may include the burden of these tests for patients. This study evaluated the burden of cervical ultrasonography (US), endoscopic ultrasonography (EUS), computed tomography (CT) and positron emission tomography (PET) in patients with esophageal carcinoma (EC).

METHODS

Consenting consecutive patients underwent a standard preoperative work-up. Burden of testing was evaluated with a self-report questionnaire addressing anxiety, embarrassment, and discomfort, each measured on a 1(none) to 5 (extreme) point-scale. An overall burden score was calculated by summing the three item scores. In addition, patients were asked to rank the four tests from least to most inconvenient. Statistical analysis was performed with nonparametric tests.

RESULTS

82 patients (67 , 15 ; mean age 64.3 yrs) participated. For most tests and most dimensions of burden, the large majority of subjects was in categories 1 and 2.With respect to anxiety, the rank order (from highest burden to lowest burden) was EUS, US, PET, and CT (average scores 1.7, 1.5, 1.4, and 1.2, respectively). For embarrassment, the rank order was EUS, PET, US, and CT (1.9, 1.5, 1.4, and 1.3 respectively). For discomfort, the rank order was EUS, PET, US and CT (2.0, 1.6, 1.4, and 1.2, respectively). And for total burden, the rank order was EUS, PET, US and CT (5.6, 4.6, 4.2, and 3.7). PET was ranked as least inconvenient by 35% of patients and as most inconvenient by 16% compared with the other tests.

CONCLUSION

Significant but small differences were observed in patient burden for imaging tests to evaluate EC. The perceived burden of PET was lower than that of EUS, but higher than the burden of CT. However absolute values were low for all tests and therefore patient burden will not be a key feature for the construction of an optimal staging algorithm for EC.

Limited additional value of positron emission tomography in staging oesophageal cancer

BACKGROUND

The detection of distant metastases in patients with oesophageal cancer may be improved with [(18)F]fluorodeoxyglucose positron emission tomography (FDG-PET), preventing unnecessary surgical explorations. The aim of this study was to assess the additional value of FDG-PET after a state-of-the-art preoperative staging protocol.

METHODS

All patients in this prospective cohort study were staged with multidetector computed tomography, endoscopic ultrasonography and external ultrasonography of the neck, both combined with selective fine-needle aspiration cytology. Patients considered eligible for curative surgery after these investigations underwent FDG-PET.

RESULTS

FDG-PET revealed suspicious hot spots in 30 (15.1 per cent) of 199 patients. Metastases were confirmed in eight (4.0 per cent). In six of these, distant metastases were confirmed before surgery, but exploratory surgery was necessary for histological confirmation in the other two. All eight upstaged patients had clinical stage III-IV disease before FDG-PET (6.6 per cent of 122 with stage III-IV disease). In seven patients (3.5 per cent) hot spots appeared to be synchronous neoplasms, mainly colonic polyps. However, those in the remaining 15 (7.5 per cent) were false positive, leading to unnecessary additional investigations.

CONCLUSION

FDG-PET improves the selection of patients with oesophageal cancer for potentially curative surgery, especially in stages III-IV. However, the diagnostic benefit is limited after state-of-the-art staging, and so broad implementation in daily clinical practice is questionable.

Fluorine-18 fluorodeoxyglucose positron emission tomography (PET) to detect vital retinoblastoma in the eye: preliminary experience

BACKGROUND/AIMS

To report our first experience with FDG-PET in the detection of vital retinoblastoma.

METHODS

Four newly diagnosed retinoblastoma patients, two treated retinoblastoma patients, and four control patients were enrolled in this pilot study. F18-FDG uptake was assessed in the light of clinical and histopathological features.

RESULTS

PET discriminated between new patients and controls, although tumor uptake varied widely. PET added no useful information with regard to possible vital tissue in tumor scars in the eye of the two treated retinoblastoma patients. Moreover, PET findings did not correlate with clinical or histopathological features.

CONCLUSION

Based on this small pilot study, F18-PET shows little promise in the detection of retinoblastoma. More research on other radiofarmacons is recommended.

Prospective use of serial questionnaires to evaluate the therapeutic efficacy of 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) in suspected lung cancer

BACKGROUND

A study was undertaken to study the effect of (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET) on the diagnosis and management of clinically problematic patients with suspected non-small cell lung cancer (NSCLC).

METHODS

A prospective before-after study was performed in a cohort of all 164 patients (university/community settings) referred for PET between August 1997 and July 1999. PET was restricted to cases where non-invasive tests had failed to solve clinical problems. The impact on diagnostic understanding and management was assessed using questionnaires (intended treatment without PET, actual treatment choice after PET, post hoc clinical assessment).

RESULTS

Diagnostic problems especially pertained to unclear radiological findings (n=112; 63%), mediastinal staging (n=36; 20%), and distant staging issues (n=16; 9%). PET findings were validated by reviewing medical records. PET had a positive influence on diagnostic understanding in 84%. Improved diagnostic understanding solely based on PET was reported in 26%. According to referring physicians, PET resulted in beneficial change of treatment in 50%. Cancelled surgery was the most frequent change in treatment after PET (35%).

CONCLUSION

FDG PET applied as "add on" technology in patients with these clinical problems appears to be a clinically useful tool, directly improving treatment choice in 25% of patients. The value of increased confidence induced by PET scanning requires further evaluation.

Detection of osteomyelitis using FDG and positron emission tomography

A positron emission tomography (PET) scan with 2-[fluorine-18]fluoro-2-deoxy-D-glucose ((18)FDG) was performed on a patient with clinical and laboratory signs of infection after a removed hip prosthesis but with indistinct signs on the bone scan and radiographs. The PET scan confirmed the clinical and laboratory signs and revealed an unidentified focus of infection in the distal area of the right femur.

[Clinical thinking and decision making in practice. A patient with anal cancer and hypercalcemia]

A 57-year-old male patient, recently known with an anal carcinoma with inguinal lymph node involvement, was admitted because of anorexia, nausea, vomiting and constipation. On physical examination the patient was dehydrated, and a systolic murmur, grade III/VI, punctum maximum apex cordis, was heard. Serum calcium was raised (4.50 mmol/l), as was the serum creatinine (328 mumol/l). Both values had been normal 14 days before admission. Serum parathormone was suppressed. A bone scan did not reveal evident lesions in the skeleton. FDG-PET scan showed uptake of the tracer into the bone marrow. A bone biopsy showed metastasis of a squamous cell carcinoma. Shortly after that the patient died. Hypercalcaemia is associated with cancer. Colorectal/anal carcinomas have a low incidence of hypercalcaemia. The prognosis of patients with cancer associated with hypercalcaemia is poor.

Positron emission tomography for the detection of metastases of differentiated thyroid carcinoma

OBJECTIVE

To show the value of positron emission tomography (PET) with 18-F-fluorodeoxyglucose (18-FDG) for the detection of metastases of differentiated thyroid carcinoma in selected patients.

PATIENT HISTORIES

There were four patients, who had undergone total thyroidectomy for papillary (two) or follicular thyroid carcinoma (two). All patients had subsequent treatment with (131)iodine. Three patients had an increasing serum concentration of thyroglobulin, one patient had antibodies against thyroglobulin. A diagnostic (131)iodine scintigraphy was negative in two patients, and uncertain in two patients. Positron emission tomography was performed about 45 min after administration of 10 mCi 18-F-fluorodeoxyglucose. In three patients PET showed uptake in the cervical region, caused by lymph node metastases in two (confirmed by neck dissection) and recurrent tumor on the trachea in one patient (confirmed by surgery). In the fourth patient uptake of 18-FDG was seen in the neck and in both lungs. This led to discontinuation of treatment with (131)iodine because the lung metastases did not accumulate (131)iodine.

DISCUSSION

In selected patients with differentiated thyroid carcinoma with an increasing serum concentration of thyroglobulin, PET is an important diagnostic option when scintigraphy with (131)iodine is negative or uncertain. In the four presented case histories, the results of PET led to a therapeutic decision: surgery in three patients and discontinuation of (131)iodine in one patient. The development of guidelines for the use of PET in the diagnosis of recurrent thyroid cancer is discussed.

[Added value of positron emission tomography with fluoro-18-deoxyglucose as the tracer (FDG-PET) in clinical problem cases in oncology]

Positron emission tomography with fluoro-18-deoxyglucose as tracer molecule (FDG-PET) is a relatively new imaging technique used in oncology to study tumour metabolism in vivo. Both qualitative and quantitative data obtained by PET provide unique information to the clinician and may guide the therapeutic approach in selected patients, where conventional diagnostic tests like CT or MRI yield equivocal results. According to the experience obtained in the Vrije Universiteit Medical Centre in Amsterdam, the additional value of FDG-PET can be explained by the sensitivity and the specificity of the technique, combined with the visualization of the whole body. FDG-PET may reveal metastases and tumour tissue may be differentiated from scar tissue and necrosis. PET is expensive and its effects on patient outcome has yet to be established.

Metabolism of radioiodinated fatty acid analogs in ischemic and hypoxic canine myocardium

Myocardial metabolism of 17-[123I]-iodoheptadecanoic acid (IHDA), 15-(p-[131I]-iodophenyl)pentadecanoic acid (pIPPA) and 15-(p-[125I]-iodophenyl)-3,3-dimethylpentadecanoic acid (DMIPP) was assessed during ischemia and hypoxia. The simultaneous investigation allowed us to evaluate differences in metabolic handling of these three fatty acids.

METHODS

In 17 open-chest dogs, the left ascending coronary artery was cannulated and extracorporeal bypass (ECB) perfused. In 3 dogs, ECB flow was kept normal, and these control experiments showed that kinetics of the radioiodinated fatty acids were not affected by the ECB technique itself. In 9 dogs, ECB flow was reduced to one third (ischemia), and in 5 dogs, the ECB area was perfused with venous blood and was kept at control values (hypoxia). After simultaneous intravenous injection of IHDA, pIPPA and DMIPP, seven paired biopsy specimens from the native and ECB-perfused myocardium were taken over an assay period of 35 min. Total activity and the distribution in the aqueous phase and lipid fractions were determined, and time-activity curves were constructed.

RESULTS

In ischemic (Is) but not in hypoxic (Hy) myocardium, peak total activity of IHDA, pIPPA and DMIPP decreased significantly versus normal (N) myocardium (IHDA: N = 700 +/- 267 versus Is = 335 +/- 158 dpm/mg/mCi; pIPPA: N = 988 +/- 318 versus Is = 438 +/- 180 dpm/mg/mCi; DMIPP: N = 352 +/- 146 versus Is = 179 +/- 82 dpm/mg/mCi; all P values < 0.001). The relative decrease was similar for IHDA, pIPPA or DMIPP. Half-time values of total activity were prolonged for IHDA and pIPPA but were shortened for DMIPP in ischemic and hypoxic myocardium (IHDA: N = 22, Is = 44 and Hy = 50 min; pIPPA: N = 24, Is = 95 and Hy = 169 min; DMIPP: N = 528, Is = 409 and Hy = 115 min). The aqueous phase activity for IHDA, pIPPA and DMIPP decreased significantly versus normal myocardium in both ischemic (IHDA: N = 71% +/- 9% versus Is = 36% +/- 9%, P < 0.001; pIPPA: N = 62% +/- 10% versus Is = 25% +/- 8%, P < 0.001; DMIPP: N = 26% +/- 11% versus Is = 18% +/- 3%, P < 0.05) and hypoxic (IHDA: N = 76% +/- 8% versus Hy = 62% +/- 8%, P < 0.05; pIPPA: N = 66% +/- 8% versus Hy = 46% +/- 10%, P < 0.05; DMIPP: N = 32% +/- 6% versus Hy = 24% +/- 4%, P < 0.05) myocardium. The relative decrease was significantly highest for pIPPA and lowest for DMIPP. Incorporation into triacylglycerols increased significantly for IHDA, pIPPA and DMIPP in both ischemic and hypoxic myocardium. In normal myocardium, DMIPP was already mainly incorporated into triacylglycerols. Activity of IHDA and pIPPA in acylcarnitine increased significantly in ischemic and hypoxic myocardium.

CONCLUSION

Kinetics of the radioiodinated fatty acid analogs in myocardium are altered during oxygen deprivation in a similar fashion as documented in literature for natural fatty acids. However, the changes were different between IHDA, pIPPA and DMIPP, suggesting different metabolic handling and thus reflecting different aspects of myocardial fatty acid metabolism.

Sentinel lymph node biopsy in breast cancer: guidelines and pitfalls of lymphoscintigraphy and gamma probe detection

BACKGROUND

Sentinel node (SN) biopsy appears to offer an alternative to routine axillary lymph node dissection (ALND) for staging patients with breast cancer. Various techniques have been studied for identifying the SN, using vital blue dye or radioactive colloid, and initial reports are promising. The inherent limitations and pitfalls must be clearly understood before SN biopsy can be implemented in dinical practice.

STUDY DESIGN

In a prospective trial, the feasibility of using lymphoscintigraphy and gamma probe detection for performing SN biopsy was studied. In 130 consecutive patients with T1-T2, N0 breast cancer, preoperative lymphoscintigraphy was performed with technetium 99m-colloidal albumin. During ALND, the radioactive axillary SNs were localized by the gamma probe. Histopathologic examination of the harvested SNs was compared with the status of the axillary lymph nodes.

RESULTS

Axillary focal accumulations were clearly identified on lymphoscintigraphy in 116 patients (89%). The failure rate was significantly higher in patients who had a previous excision biopsy (36%) than in those with a palpable tumor in situ (4%). Using the gamma probe, radiolabeled axillary SNs were successfully biopsied in 122 patients (94%). Because 18 of these patients did not undergo formal lymphadenectomy, the predictive accuracy of SN biopsy was analyzed in 104 patients. Radioactive nodes revealed metastases in 44 of 104 patients (42%); in 26 of them (59%), these were the only involved axillary nodes. The SN was negative in 60 patients (58%); in one patient the ALND was found to contain metastatic disease (1.7% false negatives). Biopsy of the SN was 98% accurate in predicting the absence of nodal metastases.

CONCLUSIONS

There are certain guidelines for performing SN biopsy by lymphoscintigraphy and gamma probe detection. Success depends primarily on an adequate functional capacity of the SN, necessary for sufficient nodal uptake to ensure accurate identification. Lymphoscintigraphy defines the pattern of lymph flow and may prevent failure or false-negative biopsies. Biopsy of the SN is a highly accurate, minimally invasive method of staging patients with breast cancer and can substantially reduce the morbidity and costs of surgical treatment by avoiding unnecessary ALND in the majority of patients.

Sodium, blood pressure, and arterial distensibility in insulin-dependent diabetes mellitus

We investigated 24-hour ambulatory blood pressure and arterial distensibility, a marker of biophysical vessel wall properties, in 32 normoalbuminuric type I diabetic patients and 32 healthy control subjects on diets containing 50 mmol and 200 mmol sodium per day. The increase in daytime diastolic blood pressure from 50 to 200 mmol sodium was significantly higher in the diabetic patients than in the control subjects (2.3+/-4.9 versus 0.2+/-3.7 mm Hg, P<.05). On a high sodium regimen, femoral artery distensibility was decreased in the diabetic patients compared with the control subjects (19.2+/-7.6 versus 24.1+/-9.3 10[-3]/kPa, P<.05). Angiotensin-converting enzyme inhibition in the diabetic patients on a high sodium diet decreased daytime diastolic blood pressure and increased femoral artery distensibility. The blood pressure decrease in response to angiotensin-converting enzyme inhibition correlated significantly with the blood pressure increase to sodium (for 24-hour systolic and diastolic blood pressure, r=.72, P<.001 and r=.76, P<.001). In addition, we found that in the diabetic patients on a high sodium diet, the renal blood flow response to exogenous angiotensin II was not bimodally distributed, as is the case in essential hypertension, in which a subgroup of the patients are characterized by sodium sensitivity of the blood pressure and an abnormal renal blood flow response to exogenous angiotensin II ("nonmodulator phenotype"). These results show that blood pressure in insulindependent diabetes mellitus is sodium sensitive, but that this is not related to the nonmodulator phenotype, and suggest that in IDDM a relatively high sodium intake may be a factor that predisposes to the development of diabetic vascular disease.

Heterogeneity of DMIPP uptake and its relationship with heterogeneous myocardial blood flow

To assess its potential role as a new metabolic probe, the relationship between regional uptake of the 15-(p-[125I]-iodophenyl)-3,3-dimethylpentadecanoic acid (DMIPP) fatty acid analog and myocardial blood flow was studied.

METHODS

In 14 open-chest dogs, the left anterior descending coronary artery was cannulated and extracorporal bypass-perfused at normal (control group; n = 4) and reduced flow (intervention group; n = 10). Myocardial blood flow (MBF) was assessed with 46Sc-labeled microspheres. Forty minutes after intravenous injection of DMIPP, the heart was excised and cut into 120 samples. In each sample, MBF ml x g(-1) x min(-1) and DMIPP uptake (percentage of the injected dose per gram, %ID/g) were assessed.

RESULTS

In normal myocardium, MBF and DMIPP uptake were 1.10 +/- 0.18 ml x g(-1) x min(-1) and 1.18 +/- 0.42 x 10(-2) %ID/g, respectively. In the extracorporal bypass area, flow was reduced to 0.49 +/- 0.20 ml x g(-1) x min(-1) (p < 0.0001 compared to normal), and DMIPP uptake was decreased to 0.75 +/- 0.26 x 10(-2) %ID/g (p < 0.0001 compared to normal). DMIPP uptake and MBF positively correlated in normal (DMIPP uptake = 0.77 +/- 0.23 x MBF; r = 0.41; p < 0.0001) and hypoperfused (DMIPP uptake = 0.35 +/- 0.70 x MBF; r = 0.63; p < 0.0001) myocardium. The heterogeneity, indicated by the coefficient of variation, in normal myocardium was 0.23 +/- 0.05 for MBF and was lower (p < 0.0001) for DMIPP uptake: 0.13 +/- 0.05. During flow reduction, heterogeneity increased significantly (p < 0.0001) for both MBF (0.59 +/- 0.22) and DMIPP uptake (0.37 +/- 0.23). Also heterogeneity of the DMIPP uptake to MBF ratio, as an indicator of agreement, increased from 0.23 +/- 0.07 in normal to 0.46 +/- 0.19 in hypoperfused myocardium (p < 0.0001).

CONCLUSION

DMIPP detects regionally hypoperfused myocardium, in which agreement between MBF and fatty acid uptake deteriorates. DMIPP uptake shows a different relationship with MBF in hypoperfused compared to normal myocardium. These observations suggest that DMIPP uptake may provide additional, unique information on regional myocardial ischemia.

Impact of lymphoscintigraphy on sentinel node identification with technetium-99m-colloidal albumin in breast cancer

Identification of the sentinel node by using colloidal tracers and a gamma probe or lymphoscintigraphy could be an effective alternative for the complicated original dye-oriented approach. We studied the sentinel node detection rate using early and delayed imaging in breast cancer patients.

METHODS

Thirty-seven patients were imaged 2 hr and 18 hr after peritumoral injection of 99mTc-colloidal albumin. Preoperatively, axillary foci were located with a handheld gamma probe that was also used to isolate radiolabeled nodes from the axillary dissection specimens. The predictive value of the sentinel node for the axillary tumorstatus was evaluated with histological examination.

RESULTS

Two and 18 hr after injection, lymphoscintigraphy revealed one to three separate axillary lymph nodes in 33 and 34 patients, respectively. In 30 patients the axillary foci were easily localized with the gamma probe preoperatively. In all 34 patients (92%), with visualized axillary foci, at least one radioactive sample could be retrieved using the gamma probe (total 53 samples). Metastases were found in the sentinel nodes of 11 patients, in seven of 11 being the only tumor-positive lymph node in the axilla. There were no false-negative sentinel nodes.

CONCLUSION

The selective targeting and prolonged intranodal retention of 99mTc-colloidal albumin allows successful sentinel node identification in most (92%) patients.

Comparison of uptake, oxidation and lipid distribution of 17-iodoheptadecanoic acid, 15-(p-iodophenyl)pentadecanoic acid and 15-(p-iodophenyl)-3,3-dimethylpentadecanoic acid in normal canine myocardium

The kinetics of 17-[123I]iodoheptadecanoic acid (IHDA), 15-(p-[125I]iodophenyl)pentadecanoic acid (pIPPA) and 15-(p-[131I]iodophenyl)-3,3-dimethylpentadecanoic acid (DMIPPA) were investigated in normal canine myocardium. After simultaneous intravenous injection, myocardial biopsy specimens and samples of arterial blood were taken over 80 min. IHDA showed the highest myocardial uptake (995 +/- 248 dpm/mg.mCi versus pIPPA: 785 +/- 197 dpm/mg.mCi, ns) and the largest size of oxidation (74% +/- 4% versus pIPPA: 65% +/- 5%, p < 0.05). Myocardial activity of IHDA decreased with a half-time value of 11.2 min (pIPPA: 13.2 min). Phospholipids were the main lipid fraction into which IHDA was incorporated, whereas pIPPA was predominantly incorporated into triacylglycerols. DMIPPA myocardial activity remained constant during the assay period and instead of being oxidized, DMIPPA was mainly incorporated into triacylglycerols (55% +/- 12%). The myocardium-to-blood ratios of DMIPPA were greater than 10:1. The ratios at peak for IHDA and pIPPA were 4.1:1 and 3.9:1, respectively (both p < 0.0001 versus DMIPPA). In conclusion, differences have been found in the myocardial uptake, oxidation and lipid distribution of IHDA, pIPPA and DMIPPA. DMIPPA is a promising tracer for fatty acid uptake studies with single-photon emission computerized tomography because of its prolonged retention and high myocardium-to-blood ratios.

Incorporation of radioiodinated fatty acids into cardiac phospholipids of normoxic canine myocardium

The aim of this study was to assess the phospholipid distribution of radioiodinated 17-iodoheptadecanoic acid (IHDA), 15-(p-iodophenyl)pentadecanoic acid (p-IPPA) and 15-(p-iodophenyl)-3,3-dimethylpentadecanoic acid (DMIPPA) under normoxic conditions and to compare these data with the fatty acid composition of the phospholipid classes. After simultaneous i.v. injection of the radioiodinated fatty acids (I-123-IHDA; I-131-p-IPPA; I-125-DMIPPA) in open-chest dogs seven myocardial biopsies were taken over 40 min (n = 26). After lipid extraction of the biopsies the organic phase was analyzed for both neutral and polar lipids by two different TLC systems. The following polar lipid fractions were analyzed: lysophosphatidylcholine (LPC), sphingomyelin (SPH), phosphatidylcholine (PC; lecithin), phosphatidylinositol (PI), phosphatidylserine (PS), phosphatidylethanolamine (PE), diphosphatidylglycerol (DPG; cardiolipin) and neutral lipids. Fractions were counted in a gamma well counter and corrected for cross-over and recovery. Results of the polar phospholipids analysis showed that IHDA has the highest incorporation into the phospholipids. The IHDA was mainly incorporated into PI (45.6%) followed by PC (30.9%), PE (14.0%) and PS (5.6%). The p-IPPA was predominantly incorporated incorporated into PC (37.2%), followed by PS (20.1%) and PE (13.7%). In contrast to IHDA, incorporation of p-IPPA into PI was small (6.4%). The DMIPPA analogue was incorporated into phospholipids to only a very small degree, compared to IHDA and p-IPPA.(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of fenoldopam on renal haemodynamics and natriuresis in chronic renal failure

The effect of oral administration of fenoldopam, a dopamine-1 receptor agonist, on blood pressure, renal haemodynamics and natriuresis was studied in 12 patients with chronic renal insufficiency. In addition, the effect of administering a low intravenous dose of fenoldopam on top of the oral dose was compared with the effect of the same intravenous dose given immediately before oral fenoldopam. Oral administration of fenoldopam (50 mg t.i.d. for 3 +/- 1 days followed by 100 mg t.i.d. for 8 +/- 1 days) induced a significant fall in blood pressure (median MAP from 107 to 101 mm Hg). Compared to baseline values, body weight, effective renal plasma flow (ERPF), glomerular filtration rate (GFR) and fractional sodium excretion remained unchanged. Infusion of fenoldopam (0.05-0.1 micrograms/kg/min) on day 1 led to a significant fall in blood pressure (median mean arterial pressure from 107.0 to 98.5 mm Hg), and a significant rise in effective renal plasma flow (median ERPF from 132 to 146 ml/min/1.73 m2). Median fractional sodium excretion increased significantly from 2.1 to 3.3%. GFR, filtration fraction and plasma aldosterone concentration did not change. No relationship was found between the fenoldopam-induced changes in ERPF and natriuresis, nor between baseline GFR or ERPF and fenoldopam-induced urinary sodium loss. Infusion of fenoldopam while patients were on oral fenoldopam had no effect on blood pressure, ERPF or GFR. However, again natriuresis was induced, which did not differ significantly from the fenoldopam-induced natriuresis on day 1. We conclude that oral fenoldopam has a moderate blood pressure lowering effect in patients with chronic renal insufficiency, but exerts no effect on ERPF or GFR. Secondly, a fenoldopam-induced natriuresis does not appear to be related to changes in ERPF or aldosterone secretion.