Simultaneous evaluation of renal morphology and function in live kidney donors using dynamic magnetic resonance imaging.

BACKGROUND: Evaluation of potential kidney donors requires the assessment of both kidney anatomy and function. In this prospective study, we sought to expand the diagnostic yield of magnetic resonance (MR) by adding functional measurements of glomerular filtration rate (GFR) and split renal function. METHODS: Between 2007 and 2009, all potential kidney donors presenting to our facility underwent a comprehensive single-stop MR study that included an assessment of anatomy, angiography and functional measurements. GFR was measured after a bolus injection of gadobutrol (4 ml, approximately 0.05 mmol/kg) and calculated from the washout of the signal intensity obtained over the liver. Split renal function was calculated from the increase of signal intensity over the renal cortex. Values were compared to renal scintigraphy with (99m)Tc-DTPA from the same day. RESULTS: The MR investigation was successfully performed in 21 participants. The GFR derived from MR (MR-GFR) correlated well (r = 0.84) with the GFR derived from scintigraphy (DTPA-GFR). The mean value of the paired differences was 4 +/- 13 [SD] ml/min/1.73 m(2) and was not significantly different from zero. The ratio between right and left kidney function was similar with both techniques (1.01 +/- 0.17 with MR and 1.06 +/- 0.12 with scintigraphy, P = 0.20). CONCLUSIONS: We demonstrate an MR-based approach to comprehensively evaluate both kidney anatomy and function in a single investigation, thereby facilitating the evaluation of potential kidney donors.

Rituximab for treatment-resistant extensive Wegener's granulomatosis--additive effects of a maintenance treatment with leflunomide.

Extensive Wegener's granulomatosis (WG) is treated by glucocorticosteroids (GC) and cyclophosphamide (CYC). In some cases, the disease is refractory to CYC. For those patients the depletion of B-lymphocytes with rituximab is a promising new treatment modality. This is a retrospective study of six patients receiving rituximab (RTX) with 4 x 375 mg/m(2) body surface weekly because of inefficacy of CYC. Proteinase-3-antineutrophil cytoplasmic antibodies (PR3-ANCA) and c-ANCAs were assessed. For clinical follow-up the Birmingham Vasculitis Activity Score for WG (BVAS/WG) was used. In five of the six cases, leflunomide (LEF) was given as maintenance treatment. Mean follow up was 16 months (12-21 months). The median PR3-ANCA titer fell from 36.8 U/ml at baseline to 21.4 U/ml after 3 months, 8.3 after 6 months, and 4.3 at month 12. The median BVAS/WG at baseline was 5 and 0 after 1 month. Two minor relapses could be noticed at month 3. After 6 months, one patient still had a BVAS of 1, all the others had a BVAS of 0. At month 18, a major relapse occurred in one patient, which was successfully retreated with RTX. The RTX infusions were well tolerated. Rituximab is a well-tolerated, very effective medication for patients with Wegener's granulomatosis. Leflunomide maintenance may increase the efficacy of rituximab and prolong the disease-free period.

Improved estimation of GFR by serum cystatin C in patients undergoing cardiac catheterization.

Clinical assessment of glomerular filtration rate (GFR) mainly relies on single determinations of serum creatinine (crea) which is commonly insensitive to mild renal dysfunction. Serum cystatin C (cysC) has been proposed as an alternative endogenous marker of GFR showing higher correlation to standard clearance methods such as inulin or iohexol clearance. We compared serum crea and cysC levels in n=127 patients undergoing cardiac catheterization. The clearance of the iodinated contrast dye iopromide served as reference method for GFR. Serum cysC was determined by a particle-enhanced immunonephelometric method. CysC showed higher non-parametric correlation (r=0.805) to the iopromide clearance compared to crea (r=0.652) and to the estimated GFR according to the Cockcroft-Gault formula (r=0.690), which underestimated true GFR systematically. Receiver operating curves revealed a greater area-under-the-curve (AUC) for cysC (0.957 vs. 0.801, p<0.05). At a cut-off level of >1.3 mg/l cysC exhibited an 88% sensitivity and a 96% specificity for detecting renal dysfunction which was defined as an iopromide clearance less than 80 ml/min/1.73 m2; best values for crea were 63% for sensitivity and 80% for specificity at a cut-off of >1.2 mg/dl. In conclusion, cysC detected reduced GFR more reliably and at an earlier stage in patients undergoing cardiac catheterization allowing a better identification of patients with renal dysfunction and those at risk for contrast damage.

Microalbuminuria in essential hypertension. Reduction by different antihypertensive drugs.

The effects of four different antihypertensive drugs (the Ca(2+)-channel blocker felodipine, the beta-blocker metoprolol, the angiotensin converting enzyme inhibitor ramipril, and the alpha-blocking agent doxazosin) on microalbuminuria and renal hemodynamics were evaluated in a double-blind, crossover study in 17 patients (10 women, seven men, aged 39 +/- 14 years) with mild-to-moderate essential arterial hypertension and microalbuminuria. Patients were studied after a 2-week placebo phase preceded by 2 weeks off all medication and after 12 weeks of treatment with each drug. Between each drug treatment, there was another 14-day placebo washout period. At the end of the study, we performed two additional 2-week placebo periods. After each placebo and treatment period, we measured albumin excretion during a 3-day collecting period. Renal hemodynamics were assessed by clearance techniques (inulin and p-aminohippurate clearance) at the end of the first and last placebo periods and after each treatment period. All drugs reduced mean arterial pressure and microalbuminuria to a similar and statistically significant (p < 0.05) extent (mean arterial pressure: placebo phase, 116 +/- 5 mm Hg; felodipine, 101 +/- 4 mm Hg; metoprolol, 101 +/- 5 mm Hg; ramipril, 101 +/- 4 mm Hg; doxazosin, 102 +/- 5 mm Hg; urinary albumin excretion: placebo phase, 46 +/- 50 mg/day; felodipine, 18 +/- 23 mg/day; metoprolol, 14 +/- 12 mg/day; ramipril, 16 +/- 16 mg/day; doxazosin, 14 +/- 14 mg/day). Mean arterial pressure levels and urinary albumin excretion returned to baseline after the last placebo period (110 +/- 6 mm Hg and 40 +/- 46 mg/day, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

On the interaction between digoxin and disopyramide.

Combined oral therapy with digoxin (0.375 mg/dl) and disopyramide (300 and 600 mg/dl) in nine subjects did not alter steady-state digoxin serum concentrations just before the daily single digoxin dose. Digoxin and creatinine clearances were not changed. After a bolus IV dose of 0.8 mg digoxin, volume of distribution (from 672 +/- 176 l to 407 +/- 153 l) and elimination t1/2 beta of digoxin were reduced significantly in five subjects after 600 mg oral disopyramide daily (from 40.2 +/- 11.7 hr to 22 +/- 7.3 hr). Total clearance and digoxin distribution t1/2 alpha did not change significantly. The clinical significance of this interaction is not clear.

Successful transplantation of highly selected CD34+ peripheral blood stem cells in a HLA-sensitized patient treated with immunoadsorption onto protein A.

BACKGROUND: Haploidentical bone marrow transplantation with preexisting anti-HLA antibodies is associated with a high risk of graft failure. METHODS: A 27-year-old female patient with chronic myeloid leukemia and evidence of several osseous chloromas had no suitable matched bone marrow donor, and fluorescence cytometric cross-match (FCXM) revealed antibodies against donor-specific HLA-molecules. Immunoadsorption onto staphylococcal protein A was applied to remove these antibodies, and peripheral stem cell transplantation was performed from her haploidentical sister after a negative FCXM was documented after immunoadsorption and conditioning treatment. RESULTS: FCXM for donor lymphocytes and stem cells remained negative throughout the posttransplant period, and engraftment of donor cells was documented on day +69. CONCLUSION: Immunoadsorption onto protein A should be considered in stem cell transplantation even from an haploidentical donor where anti-HLA antibodies and a positive FCXM are documented.

Noninvasive procedures for diagnosis of renovascular hypertension in renal transplant recipients--a prospective analysis.

The purpose of this study was to clarify the selectivity and specificity of noninvasive procedures for diagnosis of clinically suspected posttransplant renovascular hypertension. We prospectively investigated 25 renal transplant recipients with arterial hypertension and clinically suspected stenosis of the graft artery (8 female and 17 male patients; ages 45 +/- 15 years). We performed a captopril test with 25 mg captopril (n = 25), renography with technetium-99m diethylene triamine penta-acetic acid (99mTc-DTPA) before and after angiotensin-converting enzyme (ACE) inhibition with determination of glomerular filtration rate (GFR) and effective renal plasma flow (ERPF) (n = 23) and color-coded duplex ultrasonography of the transplant kidney vessels (n = 24). Renal transplant artery stenosis (RTAS) was excluded by renal arteriography in 20 patients and by operative evaluation or clinical follow-up in 5 patients. We identified 4 patients with RTAS and renovascular hypertension. The noninvasive methods showed the following results (sensitivity/specificity): (1) captopril test: 75%/67%; (2) renography combined with ACE-inhibition: 75%/84%; and (3) color-coded duplex ultrasonography: 100%/75%. We conclude that in patients with clinical evidence of RTAS most noninvasive diagnostic procedures are not sufficiently accurate to exclude the diagnosis. Only color-coded duplex ultrasonography did not fail to detect all patients with RTAS and may act as a screening test. Intraarterial renal angiography remains the most reliable and as-yet indispensable diagnostic test for transplant recipients to rule out RTAS.

The efficacy of diuretics in acute and chronic renal failure. Focus on torasemide.

Loop diuretics in high doses are the drugs of choice in the treatment of both acute renal failure (ARF) and chronic renal failure (CRF). Their pharmacokinetic and pharmacodynamic properties give them a high efficacy, even in severely compromised renal function. The serum elimination half-life and duration of action of most loop diuretics are dependent on the glomerular filtration rate and are therefore prolonged in renal failure. Torasemide, a new high ceiling and long acting loop diuretic, is as potent as furosemide (frusemide) in patients with advanced renal failure. Unlike other loop diuretics, the half-life and duration of action of torasemide are not dependent on renal function and the parent drug does not accumulate in renal failure. The extent of metabolism is clinically negligible. A number of studies have demonstrated the efficacy of furosemide, bumetanide, piretanide and torasemide in patients with ARF and CRF. When compared with the other loop diuretics, torasemide has the following advantages: a longer half-life independent of renal function, no indications of toxic side effects and apparently less influence on calciuresis.

Adenosine and extracellular volume in radiocontrast media-induced nephropathy.

Renal hemodynamic changes could play a key role in radiocontrast media-induced nephropathy (RCIN), although the pathophysiological mechanisms are unclear. We investigated the role of adenosine in RCIN caused by sodium diatrizoate (Urografin, 3 ml/kg) in nitro-L-Arg methyl ester (L-NAME)-hypertensive rats in different hydration states [eight weeks of L-NAME (50 mg/liter) in drinking water; high or low sodium intake for the last two weeks]. In clearance experiments under thiobutabarbital anesthesia in these previously mentioned animals, glomerular filtration rate (GFR), renal blood flow (RBF), and mean arterial pressure (MAP) were measured in the presence or absence of the adenosine A1-receptor antagonist 8-cyclopropyl-1,3-dipropylxanthine (DPCPX, 100 microg/kg bolus plus 10 microg/kg/hr). DPCPX or pretreatment did not change control hemodynamics. Contrast medium caused GFR and RBF to fall significantly in volume-depleted rats (from 0.29 +/- 0.02 to 0.21 +/- 0.02 ml/min/100 g and 5.4 +/- 0.3 to 4.0 +/- 0.4 ml/min, respectively) without change in MAP. In volume-expanded rats, changes were not significant (0.25 +/- 0.01 to 0.24 +/- 0.02 ml/min/100 g and 5.6 +/- 0.3 to 5.3 +/- 0.4 ml/min, respectively). In the volume-depleted rats, changes were prevented by DPCPX (0.27 +/- 0.02 to 0.24 +/- 0.02 ml/min/100 g and 4.8 +/- 0.1 to 5.0 +/- 0.1 ml/min, respectively). The acute hemodynamic effects elicited by contrast medium in L-NAME hypertensive rats thus can be prevented by volume expansion. Adenosine, via A1-receptors, contributes to the adverse effects of contrast media.

The selective adenosine A1 receptor antagonist KW-3902 prevents radiocontrast media-induced nephropathy in rats with chronic nitric oxide deficiency.

Several studies have recently suggested a principal role of adenosine in the pathogenesis of radiocontrast media-induced nephropathy. In the present experiments, we therefore investigated the renal protective effects of 8-(noradamantan-3-yl)-1,3-dipropylxanthine (KW-3902), a potent and selective adenosine A1 receptor antagonist, on radiocontrast media-induced nephropathy in the model of the N-pi-nitro-L-arginine methyl ester (L-NAME) hypertensive, chronic nitric oxide (NO)-depleted rat. Chronic NO depletion was induced by pretreatment with L-NAME, 50 mg/ml, added to drinking water for 8 weeks. Clearance experiments were performed in anesthetized rats and glomerular filtration rate was assessed prior to and following the application of high osmolar radiocontrast media (sodium diatrizoate, 3 ml/kg, i.v.) or an equivalent volume of isoosmolar mannitol to examine the role of hyperosmolarity in radiocontrast media-induced nephropathy. Subgroups received KW-3902 (0.1 mg/kg, i.v.), 20 min prior to radiocontrast media administration. Age-matched, untreated rats served as controls. Radiocontrast media application induced a significant decline in glomerular filtration rate in L-NAME hypertensive animals, whereas no effects were observed in control rats. KW-3902 fully prevented the drop in glomerular filtration rate in response to radiocontrast media in L-NAME hypertensive rats. No renal hemodynamic alterations were observed in mannitol-infused animals. The present experiments demonstrate that the decrease in glomerular filtration rate following radiocontrast media occurred independently of the osmotic load, and that KW-3902 effectively prevented the radiocontrast media-induced deterioration in renal function. KW-3902 may be especially beneficial in patients at high risk for developing acute renal failure following radiocontrast media application or in patients in which extracellular fluid volume expansion is limited by clinical conditions such as congestive heart failure.

Randomized comparison of flecainide and cibenzoline in the conversion of atrial fibrillation.

The efficacy of oral cibenzoline (260 mg/day and 320 mg/day) and flecainide (200 mg/day and 300 mg/day) in the conversion of chronic atrial fibrillation to sinus rhythm were compared in 31 patients in a randomized order. If sinus rhythm was not restored on the 5th day of oral treatment with either cibenzoline or flecainide (phase of initial treatment) patients were switched to a second phase of treatment with the drug not given in the first phase after a washout phase of 3 days. Sinus rhythm was restored in 7/28 treatment trials with cibenzoline and in 7/23 treatment trials with flecainide (not significant). Trough levels of cibenzoline and flecainide in the plasma were not significantly different between patients in whom sinus rhythm was restored and patients with persisting atrial fibrillation. In patients successfully converted to sinus rhythm, long-term treatment was instituted with flecainide (n = 6) or cibenzoline (n = 6). Atrial fibrillation developed in 2 patients in each group of patients within 3 months. In all other patients, sinus rhythm was maintained during the follow-up period of 12 months. Non-cardiac side effects were observed in 2 patients during treatment with cibenzoline and flecainide respectively. With flecainide, one patient developed sinus arrest up to 5.6 seconds.

Chlamydia pneumoniae IgA seropositivity is associated with increased risk for atherosclerotic vascular disease, myocardial infarction and stroke in dialysis patients.

BACKGROUND: Atherosclerotic cardiovascular disease is the major cause of morbidity and mortality in patients with chronic renal failure undergoing dialysis therapy. Aim of the study was to evaluate whether there is a correlation between a past infection with Chlamydia pneumoniae inducing antibody production and the manifestation of symptomatic atherosclerotic disease in patients with chronic renal failure on hemodialysis. METHODS: A retrospective study was designed including 151 dialysis patients with a clinical apparent atherosclerotic disease (case subjects) and 116 dialysis patients without any symptomatic atherosclerotic manifestation (control group). An ELISA was used to measure seropositivity for IgA and IgG titers. RESULTS: Elevated IgA titers against Chlamydia pneumoniae were found in 67% of the case subjects, but only in 29% of the controls (OR 5.34, CI 2.98-9.56). Forty-five patients of the case subjects had a history of myocardial infarction (OR 5.14, CI 2.38-11.09). Prior stroke was found in 30 patients in case subjects (OR 4.37, CI 1.73-11.01). The follow-up after 3 years showed that only 20 patients died from cardiovascular disease in the control group in comparison to 57 patients in the case group (OR 2.51). IgG seropositivity revealed an OR of 1.02 (CI 1.0-2.1). CONCLUSION: These results indicate that IgA seropositivity is associated with an increased frequency of symptomatic atherosclerotic manifestations. Especially an increased number of patients was found with prior myocardial infarction or stroke when elevated IgA titers were detected. IgA positivity seems to be a separate prospective risk factor in patients with chronic renal failure and hemodialysis for premature cardiovascular death.

Subpressor doses of angiotensin II do not increase albumin excretion in humans.

The objective of our study was to evaluate the effects of subpressor doses of angiotensin II and mild physical stress on renal hemodynamics and urinary albumin excretion (UAE) in a group of young patients with essential hypertension compared to normotensive subjects. Eleven patients (26 +/- 6 years) and ten healthy control persons (25 +/- 2 years) were enrolled in the study. Secondary forms of hypertension had been excluded. Angiotensin II was infused at a dose of 0.3 and 1.0 ng/kg/min and physical stress testing was done with a cycle ergometer (50 W at 10 min for hypertensives, 100 W at 10 min for normotensives). Renal hemodynamics were assessed by clearance techniques (continuous insulin and p-aminohippurate clearance). Mean arterial pressure (MAP) and UAE were significantly higher in the hypertensive group than in normotensive control persons at any time of measurement. There was no significant increase in MAP or UAE under angiotensin II infusion either in the hypertensive group or in the normotensive group. MAP increased significantly under physical stress in the normotensive group only (83 +/- 7 mmHg baseline vs. 108 +/- mmHg during physical stress, p < 0.05). Angiotensin II infusion resulted in a significant change concerning renal hemodynamics in the hypertensive group only. The filtration fraction increased (18 +/- 3% baseline vs. 25 +/- 7% under infusion of 1.0 ng/kg/min angiotensin II, p < 0.05) due to a decline in ERPF and an increase in GFR in the hypertensive group. The amount of UAE correlated with the magnitude of the MAP in both groups. No correlation was found between renal hemodynamic parameters and the UAE. A significant correlation was found between the norepinephrine levels and the UAE in the control group. We could not demonstrate an albuminuric effect of subpressor doses of angiotensin II in normotensive or hypertensive subjects despite its well known effects on renal hemodynamics with an increase of the filtration fraction. These data provide evidence against a predominant role of angiotensin II and renal hemodynamics concerning the elevated urinary albumin excretion in young patients with arterial hypertension.

Does L-arginine alter proteinuria and renal hemodynamics in patients with chronic glomerulonephritis and hypertension?

Endogenous nitric oxide (EDRF) plays an important role in the regulation of systemic and renal blood pressure by an alteration of vascular tone. To assess the effect of L-arginine (160 mumol/min i.v. for 3 hours), the precursor of EDRF, on blood pressure, protein-excretion and renal function (GFR = glomerular filtration rate, RPF = renal plasma flow) we performed a prospective, double blind, placebo controlled study. 18 patients with chronic glomerulonephritis (51.3 +/- 11.5 years), renal insufficiency (GFR < 65 ml/min) and hypertension were investigated for changes in GFR and RPF by continuous inulin- and PAH-clearances and for changes in permselectivity by determination of protein-excretion. L-arginine infusion results in a reduction of proteinuria (p < 0.05, t-test). There is no significant effect on renal hemodynamics and mean arterial pressure (MAP). Comparing the excretion of the endogenous proteins, only albuminuria is decreased significantly (p < 0.01), whereas IgG-excretion is reduced slightly (p < 0.05). This can be considered as an indicator of a special influence on the mesangial cells or the basement membrane of the glomerulum itself by EDRF. In conclusion L-arginine reduces protein-excretion without significant alterations in renal hemodynamics and so might prevent a decline in renal failure.

Renal hemodynamics in essential hypertensives treated with losartan.

ACE-inhibitors are known to have special renal effects, i.e. they increase ERPF, decrease the filtration fraction and lower proteinuria. These effects can be due to a decrease in angiotensin II (AII) levels as well as an increase in bradykinin. New and more specific AII-receptor antagonists may help to distinguish between effects exerted by angiotensin II and those exerted by bradykinin. We investigated the effects of losartan in 9 patients with essential hypertension (sitting mean diastolic blood pressure 95-120 mmHg). Renal hemodynamics were measured by continuous inulin-and PAH-clearance (GFR and RPF) after stopping antihypertensive therapy for 1 week, followed by a 2-week placebo period and after a 4-week treatment phase with losartan (50 mg/die) followed by a therapy with an ACE-inhibitor (ramipril 5mg/die). Additionally, urine albumin excretion (UAE) was measured. Treatment of patients with essential hypertension with losartan resulted in a significant decrease of MAP after three weeks of treatment (121 +/- 8 mmHg under placebo and 114 +/- 10 mmHg under losartan; * = p < 0.05). MAP after four weeks of losartan treatment was 115 +/- 11 mmHg. Regarding changes in renal hemodynamics we could not demonstrate a significant change for neither losartan nor the ACE-inhibitor. Urine albumin excretion was reduced by both treatment regimens in correlation to the magnitude of blood pressure reduction. Our data indicate that losartan induced a significant reduction in MAP in patients with essential arterial hypertension with only moderate effects on renal hemodynamics.

What is the best hydration regimen to prevent contrast media-induced nephrotoxicity?

BACKGROUND: Hydration is a commonly used method to prevent the decline in GFR after contrast media (CM) application. So far, there have been no controlled, randomized trials investigating the most effective route of fluid administration. METHODS: Thirty-nine patients with normal renal function (65 +/- 9 years, serum creatinine 0.9 +/- 0.2 mg/dl, GFR = 110 +/- 31 ml/min/1.73 m2) receiving at least 80 ml of low-osmolality CM during an angiographic procedure were randomized to one of the following hydration regimens: Group 1: volume expansion with 300 ml saline during CM administration (n = 20, serum creatinine 0.8 +/- 0.1 mg/dl, GFR 119 +/- 27 ml/min/1.73 m2); Group 2: intravenous administration of at least 2,000 ml saline within 12 h before and after CM application (n = 19, serum creatinine 0.9 +/- 0.2 mg/dl, GFR 101 +/- 32 ml/min/1.73 m2). GFR was measured by CM clearance (Renalyzer) at baseline and 48 hours after CM administration. The primary end point was the mean change in the GFR after 48 hours, the secondary one was the incidence of CM-induced nephropathy (CMIN), defined as a decrease in GFR of more than 50% from the baseline GFR within 48 hours. RESULTS: Patients of group 1 showed a significantly (p < 0.05) higher decline in GFR (delta GFR 34.6 +/- 25.7 ml/min/1.73 m2) compared to patients receiving the intravenous prehydration regimen (delta GFR 18.3 +/- 25.0 ml/min/1.73 m2). The incidence of CMIN was lower in prehydrated patients (5.3%) compared to the other group (15%). CONCLUSION: In patients with normal renal function, intravenous prehydration seems to be a very effective and feasible method to prevent the decline in GFR after contrast media exposure. Volume expansion given only during the CM exposure appears not to be sufficient enough to prevent renal damage.

The "point of no return" and the rate of progression in the natural history of IgA nephritis.

BACKGROUND: Based on the observation of 7 patients with chronic IgA nephritis and on a course to end-stage renal failure after several years, D'Amico et al. [1993] reported on a "point of no return" at 2.5 to 3 mg/dl serum creatinine. After exceeding this limit all 7 patients exhibited an irreversible progressive renal failure. PATIENTS AND METHODS: Therefore, 115 patients with IgA nephritis from the "German Glomerulonephritis Therapy Study" were examined in order to look for the existence of such a "point of no return". RESULTS: Three different courses could be distinguished: a stable chronic course with constantly normal or only minor elevated serum creatinine lasting for years (91 patients), a progressive course with continuously increasing serum creatinine (22 patients), and a rare (only 2 patients) early acute course with a short-term increase of serum creatinine followed by a rapid return to the normal range. After exceeding 3 mg/dl serum creatinine no remissions were observed in the progressive cases. Sixteen patients showed a rapid, continuously progressive course until end-stage renal failure with exactly the same progression as the 7 patients of D'Amico et al. Six patients of the 22 progressors were not observed long enough. The serum creatinine level doubled on average from 3 to 6 mg/dl within 10 months. CONCLUSION: Our study confirmed the existence of a "point of no return" at 3 mg/dl (265 micromol/l) during the natural course of chronic IgA nephritis.

Posttransplant renal artery stenosis--outpatient intraarterial DSA versus color aided duplex Doppler sonography.

A prospective trial was conducted to assess the accuracy of color aided duplex Doppler (CADD) sonography to rule out transplant renal artery stenosis (TRAS) and to determine feasibility and safety of intraarterial digital subtraction angiography (DSA) in hypertensive renal allograft recipients on an outpatient basis. All patients were hypertensive (n = 18, mean age: 42 +/- 11 years) and underwent CADD and an i.a. DSA with 4F catheters. There was a 4 hour rest post DSA. Duplex Doppler measurements of maximum velocity were obtained. Absolute values of > or = 100 cm/s were considered indicative to suspect TRAS. DSA revealed severe TRAS in 4 patients (22%). The stenoses were located near the iliorenal anastomosis (n = 2) and at the bifurcation of the renal artery (n = 2). Duplex Doppler classified twelve (67%) renal artery pedicles normal (maximum velocity: 79 +/- 23 cm/s). TRAS was suspected in 6 patients with a maximum velocity of 159 +/- 48 cm/s (P < 0.01). False positive CADD diagnoses were due to tortuous graft vessels and a postbiopsy arteriovenous fistula. Sensitivity of CADD was 100%, specificity 86%. There were no DSA related complications. No impairment of graft function occurred. CADD allows renal angiography to be reserved to clarify an inconclusive ultrasound study and for definite diagnosis of angiomorphology and lesion classification. Intraarterial DSA of renal grafts in outpatients may be performed without an increased risk of procedure-related complications.

Randomized controlled trial of ACE-inhibitors and beta-blockers with and without vasodilating activity in chronic glomerulonephritis.

A prospective double-blind, randomized study was conducted to compare the effects of the beta 1 antagonist, beta 2 agonist celiprolol (200 mg daily) on renal hemodynamics and protein excretion with those of the beta 1 antagonist atenolol (50 mg daily), the ACE-inhibitor ramipril (2.5 mg daily), and placebo in 11 patients with proteinuria > 400 mg/24 h due to chronic glomerulonephritis. All 4 substances were given in a double-blind, randomized manner according to a latin-square design over a period of 4 weeks with a wash-out period of 2 weeks in between. Glomerular filtration rate (GFR) and effective renal plasma flow (ERPF) were measured by inulin and PAH clearance. Proteinuria was assessed by urine sampling at the end of each treatment period. Mean arterial pressure (MAP) was reduced significantly (p < 0.01) by all 3 drugs compared to placebo (108 +/- 9 mmHg placebo, 98 +/- 12 mmHg atenolol, 101 +/- 11 mmHg celiprolol, and 98 +/- 8 mmHg ramipril). Celiprolol induced a significant increase in ERPF compared to placebo (322 +/- 109 ml/min under placebo versus 391 +/- 110 ml/min under celiprolol, p < 0.05). GFR was slightly but insignificantly increased under atenolol and celiprolol. Filtration fraction (FF) remained unchanged in case of atenolol and celiprolol treatment and was slightly but not significantly reduced by ramipril. Proteinuria was significantly (p < 0.05) reduced compared to placebo by all 3 drugs (1.8 +/- 1.3 g/24 h under placebo, 1.2 +/- 1.2 g/24 h under atenolol, 1.2 +/- 1.1 g/24 h under celiprolol, and 1.4 +/- 1.4 g/24 h under ramipril). These data demonstrate that new beta-blocking agents show favorable effects on proteinuria and renal blood flow in patients with chronic glomerulonephritis and arterial hypertension. This may be attributed to their vasodilating properties.

[TrueFISP MR imaging to determine the influence of hemodialysis on the myocardial functional parameters in patients with terminal renal insufficiency]. / TrueFISP-MR-Bildgebung zur Bestimmung des Einflusses der Hämodialyse auf myokardiale Funktionsparameter bei Patienten mit terminaler Niereninsuffizienz.

PURPOSE: To assess the characteristic signs of uremic cardiomyopathy in patients with chronic renal failure (CRF) in comparison with healthy volunteers and to determine changes of left ventricular (LV) functional parameters in patients undergoing hemo-dialysis (HD). METHODS AND MATERIALS: Using a 1.5 T Magnetom Sonata system (Siemens, Erlangen), cardiac MR imaging was performed on 26 patients (20 men, 6 women, mean age 54.7 years) and 14 volunteers (8 men, 6 women, mean age 27.7 years). Single-slice true FISP sequences (TR 3.2 ms, TE 1.6 ms, flip angel 58 degrees, matrix 256 x 208, slice thickness 5 mm) were used to obtain contiguous short axis slices covering the whole left ventricle. Patients were examined before and immediately after HD. Cardiodynamic parameters [end-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV), ejection fraction (EF), myocardial mass (MM), cardiac output (CO)] were calculated using the modified Simpson's rule (Argus Software, Siemens). Patient data were compared to reference values taken from healthy volunteers. RESULTS: As a consequence of HD, significant differences (p < 0.01) were observed for EDV (150 + 47 ml/114 + 49 ml), ESV (71 + 46 ml/60 + 56 ml), SV (79 + 25 ml/57 + 27 ml) and CO (3.6 + 1.0 l/min*m (2)/2.6 + 1.1 l/min*m (2)). Although EF (56 + 15 %/53 + 18 %) was decreased after HD, values did not differ significantly (p > 0.05). MM (148 + 47 g/148 + 52 g) and myocardial mass index (80.7 +/- 27.4 g/m (2)/80.1 +/- 9.1 g/m (2)) did not change before and after HD. In all patients, signs of LV-hypertrophy (LVH) and increased CO were diagnosed compared to reference values. In 8 of 26 patients, additional pathology, such as valvular dysfunction or global cardiac insufficiency, was detected. CONCLUSION: Cardiac MRI is an accurate tool to identify uremic cardiomyopathy in patients with chronic renal failure undergoing HD. LV functional parameters could be monitored reliably.