Assessment of renal function in clinical medicine is of great importance especially in patients with renal transplants. Cystatin C has the characteristics of an ideal marker to assess renal glomerular filtration rate. Forty patients with renal transplants under steady-state post-transplant conditions were included in the study. Steady-state was defined as lack of acute rejection periods during the last 6 months and stable cyclosporin A medication during the past 4 weeks. Gender was balanced with 20 male and 20 female patients, the mean age was 51+/-14 years, time since transplantation was 5+/-3.5 years. Fifteen percent of the patients suffered from diabetes mellitus. Immunosuppression consisted of cyclosporin A, imuran, and prednisolon. To assess renal function cystatin C, creatinine clearance, serum creatinine, and serum beta2-microglobulin were tested. Creatinine was analysed in serum and urine to calculate the creatinine clearance related to 1.73 m(2) body surface. Cystatin C and beta2-microglobulin were determined by using a particle-enhanced turbidimetric assay. Cystatin C correlated best with creatinine clearance (r=0.66), beta2-microglobulin (0.57), and serum creatinine (0.56). The diagnostic accuracy of cystatin C was significantly better than serum creatinine (p<0.05), but did not differ significantly from creatinine clearance (p=0.73), and beta2-microglobulin (p=0.46). Our data show that patients with renal transplants, cystatin C has a similar diagnostic value as creatinine clearance. However, it is superior to serum determination of creatinine and beta2-microglobulin. Cystatin C allows for rapid and accurate assessment of renal function in patients with renal transplants and is clearly superior to the commonly used serum creatinine.

We discuss vascular surgical problems in 59 kidney transplantations using alive donors. From April 96 till May 99 we harvested 59 kidneys from relatives (44 women and 15 men), mean age 54.33 years. Those kidneys were transplanted to 37 men (mean age 55.71 years), and 22 women (mean age 36.85 years). Preoperative dialysis was performed for a period of 5.015 years (mean). Thirty eight of the kidneys are right, and 21 of them are left. Six kidneys have two renal veins (10.16%), and 5 of them have two renal arteries (8.47%). We prefer end-to-end anastomosis between the donor renal artery and the recipient hypogastric artery. It ensures best regional hemodynamics, long-term patency and best positioning of the kidney avoiding vascular compression. The venous anastomosis is performed end-to-side to the iliac vein of the recipient. In 7 cases of short renal artery of the donor kidney greater saphenous vein is used as arterial conduit to ensure tension-free anastomoses. Only 1 patient (1.74%) of 59 cases (71 venous anastomoses) suffered thrombosis of the iliac vein, which caused kidney rupture. We had 5 cases of postoperative bleeding (8.47%), three of them were from the kidney hilus, and two from exposure sites. After reexploration all of them have normal function. Vascular anomalies and/or vascular disease do not preclude the procedure. Atraumatic harvesting of the kidney is critical.

The aim of the study was to evaluate the vascular surgery problems in 59 kidney transplantations from live donor, performed by the team for kidney transplantations (vascular surgeons and urologists) of Medical University--Sofia, for the period from April 1996 to May 1999. Nephrectomy was performed on 59 relatives (44 female and 15 males)--54.33 years average age. Donor kidneys were transplanted to 37 males (55.71 years average age) and 22 females (36.85 years average age). The average duration of hemodialysis prior to transplantation was 60.18 months (5.015 years). Most of donor kidneys were right--38, while only 21 were left. In six kidneys duplex renal veins were presented (10.16%), while in other 7 cases (11.76%) there were duplex renal arteries. We preferred termino-terminal anastomoses of donor renal artery to the hypogastric artery of the recipient, which provides not only better regional hemodynamics guaranteeing long term patency of the anastomoses, but presents optimal positioning of new kidney to the retroperitoneal space of recipient avoiding external compression of renal vessels. The standard performance of venous anastomoses was termino-lateral to the iliac vein of the recipient. In 7 cases, saphenous vein graft was used to replace or prolong the donor arteries or veins. Postoperative results of live donor kidney transplantation were successful in all cases, except one case (1.74% of 71 venous anastomoses) with late deep venous thrombosis of recipient's iliac vein resulting in kidney rupture and unavoidable nephrectomy. There were also 5 cases of haemorrhage (8.47%): in 3 of them from the renal hilus and in 2--profuse bleeding from the operative approach, all successfully treated after reoperation. Our satisfactory results in live donor kidney transplantation prove this method as a method of choice in certain cases of chronic renal insufficiency, especially in lack of cadaver kidneys. Contemporary vascular surgery disposes of various techniques that makes possible transplantation even in cases with serious anomalies of renal vessels. The atraumatic nephrectomy of donor kidney remains one of the main factors contributing to the successful outcome of kidney transplantation.

A rare case (the first one described in Bulgaria) of malignant intestinal lymphoma, developing in a 50-year-old patient 9 years after transplantation of a normally functioning corpse kidney, is reported. Basic predisposing factor for the lymphoma was the long-term maintenance immunosuppressive therapy with azathioprine and corticosteroids. Apart from this finding, a dissecting aneurysm of the abdominal aorta with partially obliterating thrombus was found. The patient died in a state of severe toxemia of suppurative peritonitis after perforation of the intestines heavily affected by the lymphoma.

The incidence, predisposing factors, localization, evolution and outcome of neoplasms following kidney transplantation were studied in two groups of patients--120 and 146 patients for an observation period from 1 to 16 years. In patients with adequate renal function who received immunosuppressive treatment for more than one year (accordingly 78 and 88 patients) neoplasms developed in 4 and 10 patients with mean duration of immunosuppressive treatment 4.9 and 6.1 years respectively. The neoplasms were: 3 skin cancers, 2 lung cancers, 2 Kaposi sarcomas, 1 lymphosarcoma, 1 breast cancer, 1 prostate cancer, 1 renal cancer, 1 rectal cancer and 2 polyps of the colon. The case fatality rate was 3.6 per cent. The importance of precision of the immunosuppressive treatment for reducing the incidence of these complications is pointed out.

The incidence and causes of arterial hypertension following 110 kidney transplantations in 109 patients were studied. Seventy-five patients with satisfactory renal function were observed over a period of more than a year. Of these, 46 + 2 patients received Azathioprin and 27 of them had arterial hypertension; of the 29 + 5 patients who received cyclosporin A, 18 had arterial hypertension. The incidence of hypertension and its levels were significantly higher in Azathioprin treated patients, than those on cyclosporin A treatment. Slight counter relation between arterial hypertension and blood cyclosporin A level was found. Arterial hypertension reached peak values during the first month with slight decrease on the third month, followed by further elevation. The basic reasons for arterial hypertension were rejection reactions, the own kidneys left in situ and arterial stenosis of the grafted kidney.

For the first time in Bulgaria the authors present a case of tertiary (autonomous) hyperparathyroidism, persisting in a patient who had successful kidney transplantation. Subtotal parathyroidectomy six months after the transplantation led to complete cure. Associated with the underlying disease, a rare complication was also observed in the patient--calculosis in the grafted kidney, spontaneously eliminated 40 days after the parathyroidectomy.

The frequency and the causes of arterial hypertension following renal transplantation were studied in 109 patients (110 renal transplantations). 75 patients with efficient renal function were followed up for one year. 46 + 2 of these patients received Azathioprin and 27 of them had arterial hypertension. Cycloeporin A received 29 + 2 patients and 18 of them had arterial hypertension. In the patients treated with Azathioprin a significantly greater frequency and higher values of the arterial pressure were found than in the patients treated with Cycloprorin A. A weak reverse relation was established between the arterial pressure and the serum cyclosporin A level. The arterial pressure was highest during the first month, slightly decreased at the third month and then rose again, later. Basic causes of arterial hypertension were the rejection reactions, the patients' own kidneys which were left in their place, arterial stenosis of the transplant.

A case of an 11-year-old boy is presented who had developed a severe nephrotic syndrome with massive edema, ascites, hydrothorax (protein loss with the urine up to 19 gr/24 h) 7 months after a successful kidney transplantation from a 16 years dead donor and a successfully treated crisis of transplant rejection by a good tissue compatibility. The needle renal biopsy revealed membranous glomerulonephritis I-II histological stage with data of rejection crisis by a basic disease of vesicoureteral refluxes and chronic pyelonephritis. Treatment with heparin, dipyridamole, human albumin, diuretics, sandimun and prednisolone led to a substantial improvement--mastered nephrotic syndrome, lowered to 1 g/24 h proteinuria and normal renal function.

A case is presented of a 19-year-old man suffering from focal-segmental glomerulosclerosis with terminal chronic renal failure to whom a kidney taken from his mother was transplanted. There was high blood-group and tissue compatibility between mother and son. The initial result was good, the transplanted kidney functioned well-diuresis of 3300 ml with high proteinuria. Gradually the diuresis fell to 100-200 ml. From the 29th day following the transplantation pulse urbason therapy was applied for 3 days but without effect. This led to the resumption of hemodialysis and removal of the transplanted kidney. The microscopic examination of the kidney revealed massive focal-segmental glomerulosclerosis which had led to terminal chronic renal failure. The rapid severe relapse of the disease in the transplanted kidney is explained with the malignancy of the disease and the very high compatibility between donor and recipient. It is recommended that renal transplantation in patients with focal-segmental glomerulosclerosis should not be performed with a kidney taken from a parent.

A short literary review is presented on the frequency and characteristics of the stenosis of the arterial anastomosis or of sections next to it in patients with transplanted kidney. The histories of three patients are reported. In two of the patients in the 6th and 7th month following the transplantation a severe arterial pressure appeared and a systolic murmur could be heard medially from the transplanted kidney. By renal vasography a marked stenosis of the anastomosis of the renal artery with the hypogastric artery was found. The stenosis was not corrected in time which led to its thrombosis and explantation of the kidney. In the third patient the renal vasography did not reveal stenosis of the anastomosis. In this case the symptoms were due to a chronic crisis of rejection of vasal type. The appearance of severe persistent arterial hypertension 6-7 months after a kidney transplantation is a signal for possible stenosis of the arterial anastomosis which requires timely examination and surgical correction if found.

After a brief survey, stressing upon the high susceptibility of the focal-segmental glomerulosclerosis to recurrences in transplated kidney, the authors announced one of their own observations on a youth, aged 19, that was transplated a kidney from a living donor--his mother. The basic disease in the acceptor led to chroniodialysis after 20 months of the first clinical signs. In spite of the high diuresis, that was observed after the transplantation of the maternal kidney, proteinuria persisted as early as the first days after the transplantation, creatinine did not reach the normal values and after I month chroniodialysis was again included, followed by detransplantation. The cause of that malignant course of the disease and in the transplanted kidney, the authors admitted to be the high tissue compatibility between the donor-mother and acceptor--son, one antigen in locus A and two antigens in loci B and DR. They think that with a malignant course of the focal segmental glomurolosclerosis, living donor for kidney transplantation should not be used and on no account--in case of high tissue compatibility.

The echography of transplanted kidney is a modern noninvasive investigation method with significant information value. It is easily applicable even in cases of the gravest states of the patients, allowing the dynamic observation almost immediately in the post-transplantation period. The early and chronic crisis of transplant rejection is excellently diagnosed by echography as well as of perirenal liquid collections, arterial and venous thrombosis, obstructions of excretory ducts. Results are reported from 37 echographic examinations of II kidney transplanted patients, manifesting the following complications: 8 acute crises of transplant rejection, 6--acute tubular necrosis, 3--vascular thrombosis and renal infarctions, 2--perirenal collections. 3--lightly dilated pyelo-calix system. The majority of the echographic diagnoses were confirmed by clinical-laboratory methods, X-ray examination methods and at operation.