Roberto Rivolta

Effect of Cyclosporin A on Renal Cortical Resistances Measured by Color Doppler Flowmetry on Renal Grafts

Doppler spectra were recorded at different cyclosporin A (CSA) levels (trough and peak) in 30 stable renal-transplanted outpatients: 15 with unimpaired renal function (plasma creatinine < 150 mumol/l) and 15 with renal impairment (plasma creatinine 150-350 mumol/l). Pulsatility (PI) and resistive indexes (RI) have been measured in the renal artery at the hilum and in the renal cortex. RI and PI were markedly increased (p < 0.0001) in the cortex at peak time while in the renal artery no significant changes were observed. These variations were statistically related with CSA blood levels (PI = p < 0.02; r = 0.54, RI = p < 0.05; r = 0.45). These effects were also found in the presence of renal damage. CSA dose-dependently reduces cortical blood flow, causing a persistent arteriolar vasoconstriction and a reduction in diastolic flow. This effect can be measured in man in a noninvasive and repeatable way using color Doppler sonograms.

The well-functioning renal graft evaluated by color Doppler flowmetry

The value of color Doppler ultrasound in the renal transplant follow-up has been evaluated. To do so we used a standardized protocol of analysis on a group of 86 outpatients with different transplant ages and a good and stable graft function defined as a plasma creatinine level < 105 microM/l. Renal volume increased after transplantation and averaged 198 +/- 54 cm3. The graft volume was positively related to the transplant age (p = 0.04). Mean renal blood flow/1.73 m2 body surface area was 301 +/- 98 ml/min, a value at the lower limit of normality. A statistical inverse relationship between renal blood flow and transplant age was found (p = 0.04). Renal vascular resistances increased along with the transplant age (p = 0.003). Renal function evaluated by creatinine plasma levels and creatinine clearance values did not show any statistical correlation with color Doppler findings in normal grafts. In conclusion, ultrasound measures allow us to obtain more sensitive information about the graft status and might be used for a better evaluation of the transplant follow-up.

Effect of increased arterial resistance index on long-term outcome of well-functioning kidney grafts.

Abstract An abnormal vascular status is present in the transplanted kidney. To define whether vascular factors might influence kidney function of the graft, the renal volume, blood flow and vascular resistance of a group of healthy subjects were compared with those of a group of well functioning renal transplants by color Doppler ultrasonography. Sixty healthy subjects and 75 well functioning cadaver renal transplant recipients were compared by color Doppler ultrasonography. Subsequently, 15 couples of donors and recipients of a living related renal graft were compared to observe the differences between the two organs of the same subject in a different environment. The variables studied were: the diameters and the volume of the kindey, renal blood flow and renal resistance index (RI). The group of cadaver renal transplant patients showed higher mean blood pressure (P = 0.009), higher serum creatinine levels (P = 0.0001) and lower endogenous creatinine clearance (P < 0.0001) than healthy controls. The length (P < 0.00001) and volume (P < 0.001) of the kidneys of cadaver transplanted patients were significantly greater than those of healthy subjects, while the length and volume of the living donors kidneys were identical to those of the recipients. RI, measured on renal vessels, showed lower values in healthy subjects and in kidney donors than in transplantated patients (P < 0.00001). Well functioning transplanted kidneys showed increased renal arterial RI. This non‐immunologic factor did not appear to be detrimental with renal function in time, at least until 50 months after successful grafting.

Evaluation of kidney graft function by arterial flow using colour Doppler flowmetry

Objective: Two-hundred thirty-two stable renal transplant outpatients were studied to identify the most useful colour flow Doppler ultrasound indices defining graft function in the long-term follow-up. Method: Renal artery mean velocity (Vm), renal blood flow (RBF), and resistance index (RI) on the renal and interlobar arteries were measured by the same operator. Results: Vm and RBF averaged respectively 42.1 ± 18.4 cm/s and 321 ± 95 ml/min in 85 patients with normal creatinine levels ( 105 μmol/l (P < 0.0001). An inverse correlation with the degree of renal impairment, measured by plasma creatinine levels, was shown by RBF (r = 0.73) and Vm (r = 0.69). RI increased along with the reduction of renal function (interlobar artery: r = 0.63 and renal artery: r = 0.57). Conclusions: Vm, RBF and interlobar RI appear to be sensitive parameters to describe the hemodynamical status of the graft. The hemodynamical status appears to be influenced by the graft function. RBF appears the most useful index to evaluate the blood supply in the transplanted kidney.

Cyclosporine renal cortical vasoconstriction measured by colour Doppler imaging in kidney transplantation.

Important side-effects limit the use of cyclosporine A (CSA), the most insidious of which is nephrotoxicity, which manifests as a preglomerular arteriolar vasoconstriction causing a reduction in glomerular filtration rate (GFR) and renal plasma flow (RPF). This condition is initially purely functional, but with time can become anatomic and irreversible. In clinical practice we lack suitable methods for evaluating CSA vasoconstriction. Our present knowledge is based on indirect information obtained from repeated measurerments of plasma creatinine levels and from blood concentrations of the drug. Sometimes more complex and non-routine tests, such as the evaluation of GFR and RPF, or invasive methods, such as renal biopsy, are also employed. In this study we used the colour-Doppler technique to measure directly the vascular effects of CSA in patients with transplanted kidneys, evaluating changes in blood flow at the hilus and on the cortex of the kidney when the drug was at trough or peak levels.

An unusual case of renal involvement in non-Hodgkin lymphoma

Abstract Ultrasonography of a patient with non-Hodgkin lymphoma revealed a thick subcapsular layer of lymphomatous tissue surrounding the kidney, quite separate from retroperitoneal nodes, that simulated a perirenal fluid collection or hematoma; the solid appearance on computed tomography scans and fine needle biopsy led to the diagnosis.