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[Color-Doppler and angioplasty in renovascular hypertension]
P Pavlica1, L Barozzi, G Viglietta
1Servizio di Radiologia, Ospedale Malpighi, Bologna.
Insights
Color-Doppler ultrasound shows promise for screening renovascular hypertension, a condition caused by altered kidney blood flow. However, current methods lack standardization, limiting its widespread diagnostic use.
Area of Science:
- Nephrology
- Cardiology
- Medical Imaging
Background:
- Renovascular hypertension (RVH) stems from reduced renal perfusion, activating the renin-angiotensin system.
- Effective treatments exist for RVH, necessitating accurate and accessible screening methods.
- Color-Doppler ultrasound has been explored for RVH diagnosis and treatment monitoring.
Purpose of the Study:
- To evaluate the role of Color-Doppler ultrasound in screening for renovascular hypertension.
- To identify limitations and potential improvements in Color-Doppler for RVH assessment.
Main Methods:
- Utilized B-mode ultrasound with 3.5 and 5 MHz probes.
- Focused on identifying renal arteries, including accessory ones (5-25% of cases).
- Employed small sample volumes (3-5 mm) and analyzed flowmetric parameters like resistive index and pulsatility index.
Main Results:
- Color-Doppler faces challenges in RVH screening due to variable parameters and lack of standardized methods.
- Comparison of results across different centers is difficult.
- Technological advancements may enhance standardization and repeatability.
Conclusions:
- Current Color-Doppler techniques are not ideal for widespread renovascular hypertension screening.
- Standardization of qualitative and quantitative variables is crucial for improved diagnostic accuracy.
- Future technological evolution holds potential for more reliable Color-Doppler assessment of RVH.
Abstract:
Renovascular hypertension is defined as a kind of hypertension secondary to altered renal perfusion with the activation of the renin-angiotensin system. Since a large number of these patients benefits from treatment--be it medical, surgical or angioplastic--a non-invasive low-cost method allowing accurate screening was looked for. Color-Doppler was employed by many authors to evaluate renovascular hypertension, for both the early diagnosis of the condition and the evaluation of treatment results in renal artery stenoses. However, the authors agree that color-Doppler cannot play a major role in the screening of renovascular hypertension due to the various qualitative and quantitative variables not being adequately codified, to the lack of a single color-Doppler method and to the difficult comparison of the results from the different units. Nevertheless, improved results are promised by technological evolution, together with the possibility to codify color-Doppler variables more easily repeatable. B-mode units with 3.5 and 5 MHz probes were employed in the thinnest subjects. In 5-25% of cases accessory renal arteries were observed. After identifying the vessel to be studied with several spatial scans, the smallest possible sample volume (usually 3-5 mm) was positioned. The normal flowmetric range was 0.07-0.1 s: it must not exceed 0.16 s, with persistence of high diastolic flow. Some authors' criteria were followed to define either stenosis or renal artery obstruction; moreover, pulsatile flow index was considered, together with the resistive index, pulsatility index and stenosis index.