Year : 2010 | Volume
: 21 | Issue : 2 | Page : 295--299
Early evaluation of renal hemodynamic alterations in type I diabetes mellitus with duplex ultrasound
Aasem Saif1, Neveen A Soliman2, Alaa Abdel-Hameed3,
1 Department of Internal Medicine and Endocrinology, Center of Pediatric Nephrology and Transplantation, Cairo University, Egypt
2 Department of Pediatrics, Center of Pediatric Nephrology and Transplantation, Cairo University, Egypt
3 Vascular Laboratory, Cairo University, Egypt
Neveen A Soliman
Professor of Pediatrics, Center of Pediatric Nephrology and Transplantation, Cairo University, Egyptian Group for Orphan Renal Diseases Cairo, 11451
To evaluate the role of renal duplex ultrasonography in the detection of early alteration of renal blood flow in type I diabetic patients, we studied with duplex ultrasound 32 patients with type I diabetes mellitus (19 males, 13 females, age range 8-19 years) and 35 age and sex-matched controls. The resistivity indices (RIs) and pulsatility indices (PIs) of the main renal as well as intrarenal arteries were calculated. Compared with the healthy control subjects, diabetic patients had significantly higher resistivity indices (RIs) in the intrarenal (segmental, arcuate and interlobar) arteries (P= 0.001). The study, also revealed a significantly positive correlation between the RIs in the intrarenal arteries in diabetics and the albumin/creatinine ratio (r= 0.54, 0.52 and 0.51 respectively), glycated hemoglobin (r= 0.61, 0.59 and 0.63 respectively), as well as the estimated GFR (e-GFR) (r= 0.53, 0.51 and 0.57 respectively). We conclude that the current study documented early intrarenal hemodynamic alterations in the form of pathologically elevated intrarenal RIs. This denotes the potential usefulness of duplex evaluation of the intrarenal arteries, as a noninvasive procedure, for monitoring type 1 diabetic patients to predict those at risk of diabetic nephropathy.
|How to cite this article:|
Saif A, Soliman NA, Abdel-Hameed A. Early evaluation of renal hemodynamic alterations in type I diabetes mellitus with duplex ultrasound.Saudi J Kidney Dis Transpl 2010;21:295-299
|How to cite this URL:|
Saif A, Soliman NA, Abdel-Hameed A. Early evaluation of renal hemodynamic alterations in type I diabetes mellitus with duplex ultrasound. Saudi J Kidney Dis Transpl [serial online] 2010 [cited 2021 Dec 4 ];21:295-299
Available from: https://www.sjkdt.org/text.asp?2010/21/2/295/60198
Diabetic nephropathy affects about 40% of patients with type I diabetes mellitus. Once fully developed, this complication carries a poor prognosis where reltive mortality is almost 40-100 times that of non-diabetics.  Therefore it is considered one of the most common and most serious complications in type 1 diabetes. ,
Glomerular hyperfiltration is the first feature of renal involvement and can be observed soon after the inception of diabetes, accompanied by a loss of renal functional reserve.  Microalbuminuria coincides with the morphological changes such as thickening of the glomerular basement membrane and mesangial expansion. 
Clinically evident diabetes-related microvascular complications are extremely rare in childhood and adolescence. Nonetheless, early functional and structural abnormalities may be present a few years after the onset of the disease. ,,
Doppler ultrasonography is an easy and noninvasive tool for investigating renal hemodynamics. The resistivity index (RI) calculated from blood flow velocities in vessels reflects renovascular resistance and is known to increase in various disorders. , Moreover, vasoactive agents, such as angiotensin II and its inhibitors are known to affect RI. 
This prospective study was carried out to detect possible changes in renal blood flow velocity and vascular indices by duplex ultrasonography and to correlate these changes with clinical and laboratory parameters results in children and adolescents with type I diabetes mellitus.
Patients and Methods
This study was approved by the Institutional Review Board at Cairo University Children's Hospital. Thirty two patients with type I diabetes mellitus (19 males and 13 females) with age range from 8-19 years, with a mean of 11.9 ± 3.7 years). Thirty five age and sex matched healthy children and adolescents (20 males and 15 females, age range 7-18 years, with a mean of 11.7 ± 4.8 years) were enrolled in the study. The parents and children were informed about the study and fully informed consent was obtained. The duration of diabetes in the study patients ranged from 2-17 years. All patients were normotensive, had normal renal function tests and showed no evidence of retinopathy or clinical nephropathy.
The following was done for both patients and control subjects:
Blood pressure (BP) measurement with calculation of the mean blood pressure (MBP).Laboratory investigations including: urinary Albumin/Creatinine ratio (Alb/Cr), glycated hemoglobin, and serum creatinine (Cr). Glomerular filtration rate was estimated (e-GFR) using the adapted Schwartz formula. ,Color-coded duplex ultrasound scan using 3.5 or 5 MHz transducer (HP Sonos 1500 machine, Hewlett Packard, Santa Clara, CA, USA). Patients were scanned in the supine position. The transducer was placed in the midline with slight inclination to the left to get a coronal section of the aorta. Each renal artery was identified as lying between the superior mesenteric artery and the corresponding renal vein. Flow velocities were measured by real time pulsed Doppler ultrasonography.Recordings were obtained from the main renal artery as well as its main intrarenal branches (segmental, interlobar, and arcuate). For each artery, the resistivity index (RI), the pulsatility index (PI), and diastolic systolic ratio (D/S) were measured according to the following formulas:
The mean renal RIs, PIs, and D/S ratios were used for statistical analysis of differences between patients and controls using student t-test (P value); P 0.38 was accepted as statistically significant.
Comparative analysis of the duplex results in both patients and controls revealed that the resistivity indices (RIs) in the intrarenal (segmental, arcuate and interlobar) arteries were significantly elevated in the study group compared to controls (P= 0.001). Nevertheless, there was no significant difference between the two groups regarding the RI in the main renal artery (P=0.44), pulsatility index (PI) in the main renal artery (P= 0.10) or the pulsatility indices (PIs) in the intrarenal arteries (P= 0.26, 0.09, 0.43) [Table 1].
Moreover, the study revealed a significantlypositive correlation between the RIs in the intrarenal (segmental, arcuate and interlobar) arteries in diabetics and the albumin/creatinine ratio (r= 0.54, 0.52 and 0.51 respectively) as well as glycated hemoglobin (r= 0.61, 0.59 and 0.63 respectively). Also, there was a significantlypositive correlation between the RIs in the intrarenal arteries and the e-GFR in the diabetic patients (r= 0.53, 0.51 and 0.57 respectively). No other significant correlations could be found between any of the duplex indices and the different clinical and laboratory parameters studied [Table 2].
Our results showed that many of patients with type 1 diabetes of variable duration and without the usual signs of clinical diabetic nephropathy had evidence of increased intrarenal arterial resistance compared to control subjects. It is noteworthy that these hemodynamic changes even preceded the development of microalbuminuria in some of our patients denoting that renal duplex assessment might be used as an early and sensitive tool to detect early diabetic nephropathy.
Studies of the glomerular physiologic abnormalities in diabetic nephropathy demonstrated glomerular hypertension and hypertrophy  similar to that seen in rodent models of ablative nephrectomy.  Furthermore, the elevation in capillary pressure may be damaging to glomerular endothelial, epithelial and mesangial cells; thereby intiating and contributing to the progression of diabetic nephropathy. 
Boeri et al used renal duplex to prove that the RI of the interlobar arteries as a marker of the intra-renal circulation is higher in type II diabetics compared to normal controls.  Also, Sperandeo et al found that the RI of the interlobar arteries is higher in type I diabetics (aged between 28 and 46 years) compared to controls. 
Moreover, it was clearly shown that these elevated intrarenal RIs correlated strongly with glycated hemoglobin, being higher in the poorly controlled patients, therefore implying the necessity for tighter control of diabetes to prevent, or at least delay, the incidence of nephropathic complications. 
Our results are comparable with those of another study in diabetic children, which demonstrated that RI values were significantly greater in children with diabetes and no evidence of renal dysfunction than in age-matched healthy controls; therefore, suggesting a preclinical stage of diabetic nephropathy. Moreover, the authors found that RI correlated positively with HbA1c and diabetes duration. 
Our study further demonstrates the positive correlation between intrarenal RIs and e-GFR as none of our patients showed any evidence of clinical diabetic nephropathy. It has been previously demonstrated that the intrarenal arterial resistance correlates with creatinine clearance (Ccr) differently depending upon the stage of diabetic nephropathy. Soldo et al showed a positive correlation in IDDM patients with no evidence of clinical diabetic nephropathy.  Another study clearly demonstrated that intrarenal arterial resistance is significantly increased in chronic kidney disease patients with type 2 diabetes compared to non-diabetics.  However, Ishimura et al found a negative correlation in patients with evident clinical nephropathy. 
Two final points deserve to mention. Firstly, none of the duplex indices in our study showed a significant correlation with age, sex, mean blood pressure or serum creatinine. Intrarenal RIs were, however, higher in patients with longer duration of diabetes though it failed to reach statistical significance. Secondly, our study demonstrates a strongly positive correlation between intrarenal RIs (at the segmental, arcuate and interlobar levels) and albumin/creatinine ratio.
We conclude that the current study documented early intrarenal hemodynamic alterations in the form of pathologically elevated intrarenal RIs. This denotes the potential usefulness of duplex evaluation of the intrarenal arteries, as a noninvasive procedure, for monitoring type 1 diabetic patients to predict those at risk of diabetic nephropathy.
The authors thank the patients, the control subjects and their families for participation in this study.
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