Senescence rates in patients with end-stage renal disease: a critical appraisal of the Gompertz model.

The most frequently used model to describe the exponential increase in mortality rate over age is the Gompertz equation. Logarithmically transformed, the equation conforms to a straight line, of which the slope has been interpreted as the rate of senescence. Earlier, we proposed the derivative function of the Gompertz equation as a superior descriptor of senescence rate. Here, we tested both measures of the rate of senescence in a population of patients with end-stage renal disease. It is clinical dogma that patients on dialysis experience accelerated senescence, whereas those with a functional kidney transplant have mortality rates comparable to the general population. Therefore, we calculated the age-specific mortality rates for European patients on dialysis (n=274 221; follow-up=594 767 person-years), for European patients with a functioning kidney transplant (n=61 286; follow-up=345 024 person-years), and for the general European population. We found higher mortality rates, but a smaller slope of logarithmic mortality curve for patients on dialysis compared with both patients with a functioning kidney transplant and the general population (P<0.001). A classical interpretation of the Gompertz model would imply that the rate of senescence in patients on dialysis is lower than in patients with a functioning transplant and lower than in the general population. In contrast, the derivative function of the Gompertz equation yielded the highest senescence rates for patients on dialysis, whereas the rate was similar in patients with a functioning transplant and the general population. We conclude that the rate of senescence is better described by the derivative function of the Gompertz equation.

[Atherosclerotic renal artery stenosis]. / Atherosklerotische Nierenarterienstenose.

The most common cause of obstructive renal artery disease is atherosclerosis, accounting for 90 % of cases of renal artery stenosis. Atherosclerotic renal artery stenosis can be associated with renovascular hypertension, ischemic nephropathy, or both or it may occur alone. The prevalence of atherosclerotic renal artery stenosis among hypertensive patients is estimated between 1 and 5 %, but the frequency rises among patients with refractory hypertension (20 %) coronary heart disease (15 to 20 %) or peripheral arterial disease (30 to 40 %). The gold standard for diagnosing renal artery disease is contrast renal arteriography. MR angiography, CT angiography and color duplex ultrasonography have the highest sensitivity and specifity among the non invasive screening methods. Therapy is based on consequent medical treatment of hypertension, antiplatelet therapy and modification of risk factors for atherosclerosis. Revascularisation is advised in patients with severe hypertension, in patients with pulmonary edema and cases of acute worsening of renal function. Percutaneous angioplasty with stent implantation is the method of choice for revascularisation. The prognosis of patients with atherosclerotic renal artery stenosis is determined by cardiovascular and renal complications.

Measuring disease occurrence.

Different measures may be used to describe how often disease (or another health event) occurs in a population. Incidence expresses the development of new cases and is mostly used against the background of prevention, to assess disease etiology or to determine the risk factors of disease. Depending on the specific study question, incidence may be reported as risk or as incidence rate. This paper discusses that it is preferable to use incidence rate in case of a dynamic population or in cases where the observation period is sufficiently long for competing risks or loss to follow-up to play a significant role. Prevalence is the number of existing cases, which is affected by both the number of incident cases and the length of disease time. It reflects the burden of disease on a population that may, among others, be measured in terms of costs or morbidity. Knowledge about this burden can be used for the planning of health-care facilities. This paper discusses the different measures of disease occurrence using a number of examples taken from the nephrology literature.

Present status at the Vienna Transplantation Center after four thousand renal transplantations.

The Division of Transplantation at the Medical University of Vienna, Austria was established by Dr Franz Piza, who performed the first deceased donor kidney transplantation in Vienna in 1965. During the next 43 years, 4,849 transplants were performed at this unit. Data were analysed in the time period 1993-2006 for 2,165 deceased donor transplants (1,734 first and 431 regrafts) and 263 living donor transplants. Long-term follow-up was available for more than 95% of all grafts and all recipients had at least 9 months of follow-up. Two- and 6-year graft survival rates were 81.4% and 66.3%, respectively, for first deceased donor grafts, 76.1% and 61.8% for regrafts and 91.5% and 79.1% for living transplants. Appropriate immunosuppression, HLA matching and crossmatching supported by solid basic scientific research have proved successful in achieving good graft survival at our unit.

Long-term mortality and incidence of renal dialysis and transplantation in type 1 diabetes mellitus.

AIMS: We investigated long-term mortality and requirement of renal replacement therapy (RRT) in type 1 diabetes mellitus (T1DM) to study risk factors and late complication incidence of T1DM in a prospective cohort study at Lainz Hospital, Vienna, Austria. METHODS: In 1983-1984, T1DM patients [n = 648; 47% females, 53% males; age, 30 +/- 11 yr; T1DM duration, 15 +/- 9 yr; body mass index, 24 +/- 4 kg/m(2); glycated hemoglobin (HbA1c), 7.6 +/- 1.6%] were stratified into HbA1c quartiles [1st, 5.9 +/- 0.5% (range, 4.2-6.5%); 2nd, 6.9 +/- 0.3% (6.6-7.4%); 3rd, 7.9 +/- 0.3% (7.5-8.4%); and 4th, 9.6 +/- 1.3% (8.5-14.8%)]. Twenty years later, both endpoints (death and RRT) were investigated by record linkage with national registries. RESULTS: At baseline, creatinine clearance, blood pressure, and body mass index were comparable among the HbA1c quartiles, whereas albuminuria was more frequent in the 4th quartile (+15%; P < 0.03). After the 20-yr follow-up, 13.0% of the patients had died [rate, 708 per 100,000 person-years (95% confidence interval, 557-859)], and 5.6% had received RRT [311 per 100,000 person-years (95% confidence interval, 210-412)]. Patients with the highest HbA1c values (4th quartile) had a higher mortality rate and a greater incidence of RRT (P < 0.04). In the Cox proportional hazards analysis, age, male gender, increased HbA1c, albuminuria, and reduced creatinine clearance were predictors of mortality (P < 0.05). Predictors of RRT were albuminuria (P < 0.001), reduced creatinine clearance (P < 0.001), and belonging to the 4th HbA1c quartile (P = 0.06). In Kaplan-Meier analysis, mortality was linearly associated with poor glycemia, whereas RRT incidence appeared to rise at a HbA1c threshold of approximately 8.5%. CONCLUSION/INTERPRETATION: In the Lainz T1DM cohort, 13.0% mortality and 5.6% RRT were directly associated with and more frequently found in poor glycemia, showing that good glycemic control is essential for the longevity and quality of life in T1DM.

Renal replacement therapy in Europe: the results of a collaborative effort by the ERA-EDTA registry and six national or regional registries.

BACKGROUND: In June 2000 a new ERA-EDTA Registry Office was opened in Amsterdam. This Registry will only collect core data on renal replacement therapy (RRT) through national and regional registries. This paper reports the technical and epidemiological results of a pilot study combining the data from six registries. METHODS: Data from the national renal registries of Austria, Finland, French-Belgium, The Netherlands, Norway, and Scotland were combined. Patients starting RRT between 1980 and 1999 (n=57371) were included in the analyses. Cox proportional hazards regression was used to predict survival. RESULTS: The use of different coding systems for ESRD treatment by the registries made it difficult to merge the data. Incidence and prevalence of RRT showed a continuous increase with a marked variation in rates between countries. The 2-, 5- and 10-year patient survival was 67, 35 and 11% in dialysis patients and 90, 81 and 64% after a first renal allograft. Multivariate analysis showed a slightly better survival on dialysis in the 1990-1994 (RR 0.94, 95% CI 0.90-0.98) and the 1995-1999 cohort (RR 0.88, 95% CI 0.84-0.92) compared to the 1980-1984 cohort. In contrast, there was a much greater improvement in transplant-patient survival, resulting in a 56% reduction in the risk of death within the 1995-1999 cohort (RR 0.44, 95% CI 0.39-0.50) compared to the 1980-1984 cohort. CONCLUSIONS: This study provides support for the feasibility of a "new style" ERA-EDTA registry and the collection of data is now being extended to other countries. The improvement in patient survival over the last two decades has been much greater in transplant recipients than in dialysis patients.

[Angioleiomyoma of the gallbladder: a rare cause of hemobilia in a patient on dialysis]. / Angioleiomyom der Gallenblase. Seltene Ursache einer Hämobilie bei einem Dialysepatienten.

HISTORY AND FINDINGS: Acute colicky upper abdominal pain occurred in a 47-year-old man on renal dialysis who also had chronic recurrent pancreatitis. On physical examination he was noted to be slightly jaundiced and he had slight pain when the liver edge was palpated. A few days later melaena developed and the haemoglobin concentration fell from normal levels to 6.9 g/dl. INVESTIGATIONS: Serology gave no evidence of acute pancreatitis, but biochemical tests indicated cholestasis. Ultrasonography revealed widening of the intra- and extrahepatic biliary tract. Endoscopic retrograde cholecystopancreatography demonstrated bleeding from the biliary tract (haemobilia) as the source of the bleeding. Selective angiography of the coeliac trunk showed extravasation in the region of the gallbladder. TREATMENT AND COURSE: As a vascular anomaly in the gallbladder was suspected, a cholecystectomy was performed. The surgical specimen revealed an angioleiomyoma of the gallbladder. The postoperative course was without complications and there was no further haemobilia. CONCLUSIONS: Haemobilia is a relatively rare cause of upper gastrointestinal bleeding. It is usually due to trauma (accidental or iatrogenic) to the liver or the biliary tract. Rarely, as in this case, it can be caused by a benign mesenchymal neoplasm. Clotting disorder in uraemia or intermittent heparin administration for dialysis may in this patient have contributed to the bleeding.

[AL amyloidosis--a hematologic disease with initial cardiac manifestation. 2 case reports]. / AL-Amyloidose - Eine hämatologische Erkrankung mit kardialer Erstmanifestation. 2 Fallberichte.

Cardiac involvement in AL-amyloidosis due to a multiple myeloma is present in up to 90% of cases. We present two patients with cardiac symptoms in whom a hematologic disease could be diagnosed because of suspicious cardiac finding. The leading symptom was dyspnea. The routinely performed laboratory tests, especially the erythrocyte sedimentation rate and the electrophoresis, were normal. After exclusion of coronary artery disease an infiltrative cardiomyopathy was suspected because of the echocardiographic examination with marked left ventricular hypertrophy, the restrictive flow pattern at the mitral valve and the electrocardiogram with a low voltage in limb leads and absent R waves in left precordial leads. Further, hematologic workup confirmed the production of light chains due to a myeloma. If the echocardiographic examination and the electrocardiogram raises the suspicion of an infiltrative cardiomyopathy as the cause of dyspnea, an immunofixation should be done in spite of normal laboratory tests to confirm or rule out the presence of a light chain disease due to a myeloma.

[Aneurysm of the cystic artery as a rare cause of hemobilia]. / Aneurysma der Arteria cystica als seltene Ursache einer Hämobilie.

A 52-year old woman was admitted to the hospital because of upper abdominal pain and hematemesis. Laboratory parameters showed marked cholestasis. Endoscopic retrograde cholangiopancreatography (ERCP) lead to the diagnosis of hemobilia. CT-scan and angiography revealed an aneurysm of the cystic artery as the cause of hemobilia. Cholecystectomy was performed because of concomitant cholecystitis. Anatomical examination confirmed clinical diagnosis.

Portal hypertension due to traumatic hepatic arterioportal fistula: report of successful embolization.

We report a case of severe portal hypertension due to a post-traumatic hepatic arterioportal fistula. A 77-year-old male patient was admitted for abdominal pain, inappetence and weight loss. Further clinical signs were ascites and splenomegaly. Sonography showed a marked enlargement of an arterioportal fistula, which was diagnosed some years before as a consequence of abdominal trauma during the Second World War. Angiography demonstrated an imposing dilatation of the right hepatic artery filling an intrahepatic pseudoaneurysmatic cavity with fistula formation to the portal vein. By means of selective hepatic artery embolization, complete occlusion of the right hepatic artery and the arterioportal fistula was achieved. Within 4 weeks the patient recovered and sonography showed disappearance of ascites and splenomegaly.

Initial subcutaneous embedding of the peritoneal dialysis catheter--a critical appraisal of this new implantation technique.

BACKGROUND: The objectives of this open non-randomized study were to evaluate the impact of a new peritoneal catheter placement technique on catheter maintenance, and complications possibly related to the access, e.g. leakage, infectious complications, or drainage failure. METHOD: In a routine clinical setting, a two-cuff swan-neck catheter was implanted surgically, but its external segment was embedded in a subcutaneous pouch initially without exit site to enable uncontaminated wound healing and tight ingrowth of the cuffs. After 4 weeks at the earliest the distal catheter tip was set free by a small incision under local anaesthesia, and CAPD was started. RESULTS: Using this technique, 26 catheters were implanted in 17 males and nine females (mean age 52.3 +/- 17.4, range 19-83 years). The catheters were buried subcutaneously for a median of 79.5 (mean +/- SD 132.2 +/- 157.2, range 28-675) days, and were activated in 21 patients. No leaks were seen, and only one abdominal wall abscess secondary to a haematoma was found. Long-term follow up (mean duration of CAPD 467.0 +/- 338.1, range 32-1320 days) revealed a very low overall incidence of infectious complications, i.e. 0.80 per patient-year (1 episode per 14.9 patient-months), and the incidence of catheter-related peritonitis amounted to 0.036 per patient-year (1 episode per 27.2 patient-years), only. However, the postoperative course was complicated by seromas in two of 26, and subcutaneous haematomas in 12 of 26 patients, five of which were revised surgically. At catheter activation, fibrin thrombi were found in nine of 21 patients and two had to be operated. Omental catheter obstruction was diagnosed in four patients, and followed by omentectomy. No relationship was seen between thrombus formation and omental obstruction and duration of subcutaneous embedment (P = 0.27 and P = 0.5 respectively) or patient age (P = 0.06 and P = 0.13 respectively; Mann-Whitney-test). There was also no relationship with primary omentectomy or haematoma. CONCLUSION: We conclude that although the very low incidence of infectious episodes favours the new technique, further improvement is necessary to decrease the unacceptable rate of perioperative complications. Subcutaneous embedding of the catheter may then be considered in patients with expected problems of wound healing, and those who wish to be prepared for peritoneal dialysis in time.

[Comparison between ambulatory 24-hour blood pressure measurement and occasional blood pressure measurement in hemodialysis patients with left heart hypertrophy]. / Vergleich zwischen ambulanter 24-h-Blutdruckmessung und Gelegenheitsblutdruckmessung bei Hämodialysepatienten mit Linksherzhypertrophie.

Since 24-hour blood pressure monitoring seems to be superior to occasional blood pressure measurement as far as risk stratification is concerned, we compared the two methods in patients with secondary hypertension and left ventricular hypertrophy. In 26 haemodialysis patients (12 male, mean age 54 +/- 13 years), the mean occasional blood pressure values during haemodialysis were 147 +/- 18/82 +/- 9 mmHg, the mean 24-hour blood pressure values were 145 +/- 21/ 85 +/- 13 mmHg, during the day 145 +/- 23/86 +/- 13, during the night 143 +/- 25/81 +/- 13 mmHg. The nocturnal reduction of mean blood pressure was -3.6 +/- 7%. Both methods of blood pressure monitoring showed a significant correlation with the relevant echocardiographic parameters of left ventricular hypertrophy, cardiac mass and interventricular septum diameter. Patients with and without a nocturnal reduction in blood pressure could not be differentiated by the mean occasional blood pressure values. Therefore, 24 h ambulatory blood pressure monitoring seems warranted in this high risk group, especially to monitor antihypertensive drug therapy.

Parameters of prognostic relevance to the patency of vascular access in hemodialysis patients.

The objectives of this study were to evaluate whether age, sex, underlying renal disease, or the performing surgeon is of prognostic relevance to the patency of the vascular access. In a routine clinical setting, 139 first and 144 further fistula operations were done in 139 patients during 5 yr and were analyzed in retrospect. Within a group of 108 patients with first Cimino-Brescia fistulae, Cox multivariate regression analysis revealed the surgeon to be the only determinant with a continuous, significant effect on fistula patency throughout the observation period (P(out) < 0.1). The patency rates of the seven surgeons at 1, 2, and 3 yr differed from 34 to 69, 13 to 62, and 13 to 62%, respectively. Hazard ratios among the surgeons varied from 0.65 to 2.21. Additionally, age (P < 0.004) and diabetes mellitus (P < 0.02) were disclosed to be significant risk factors for impaired patency, but later in the course of disease (time dependent). Sex had no influence. After the failure of the first fistula, revisions of or new Cimino-Brescia fistulae (N = 56) were superior to polytetrafluoroethylene grafts (N = 61). The mean patency of the former amounted to 320 +/- 377 versus 156 +/- 281 days in polytetrafluoroethylene grafts (P < 0.05). It was concluded that increasing age and diabetes mellitus are time-dependent risk factors for the shortened patency of arteriovenous fistulae. The operating surgeon, however, seems to be the major determinant for the continuous patency of Cimino-Brescia fistulae.