[Pulsed-wave color Doppler echography of the intrarenal vessels in patients with insulin-dependent diabetes mellitus and incipient nephropathy].

Diabetic nephropathy affects a subset of about 40% patients with Insulin-Dependent Diabetes Mellitus (IDDM); it also develops in a less defined percentage (30-50%) of patients with non Insulin-Dependent Diabetes Mellitus (NIDDM), after a period of 15-20 years. It is usually divided in 5 stages: the first 3 are characterized by renal hypertrophy and increased glomerular filtration surface area (I stage) followed by glomerular histological lesions (II stage) and early nephropathy with microalbuminuria (III stage). At these stages nephropathy is still reversible by medical treatment (ACE inhibitors) and good metabolic control. Aim of this study was to assess the usefulness of duplex sonography with Doppler wave form analysis in the evaluation of early diabetic nephropathy, in order to detected patients at risk for irreversible renal disease. Fifteen patients (10 males and 5 females) aged 28-46 years, affected by IDDM were studied; 15 healthy subjects (7 males and 8 females) aged 20-45 years composed the control group. All of them underwent duplex Doppler sonography of kidney; a scanner with a 3.5 MHz transducer (Toshiba 270 SSA) was used. All patients had renal function tests within normal range. Pulsatily Index (P.I.) and Resistive Index (R.I. of Doppler waveform were obtained at the interlobar arteries; the average value of 3 bilateral measurements was taken. Doppler sonography was done by the same authors without knowledge of the patient group (case or control). Both indexes (P.I. and R.I.) resulted to have higher values in patients with IDDM compared to controls: P.I. = 1.46 +/- 0.30 vs. 1.07 +/- 0.06, p < 0.05; R.I. = 0.77 +/- 0.09 vs 0.60 +/- 0.03, p < 0.05. Even if our data have to be confirmed by further studies, they suggest that duplex Doppler sonography may be a useful complementary test in the evaluation of diabetic nephropathy, even in the early stages.