Type:
Educational Exhibit
Keywords:
Hypertension, Computer Applications-Detection, diagnosis, Ultrasound-Spectral Doppler, MR-Angiography, CT-Angiography, Vascular, Kidney, Abdomen
Authors:
V. Catala, T. Martí Ballesté, L. F. Granados Palacio, J. Samaniego, X. Alomar, P. de la Torre; Barcelona/ES
DOI:
10.1594/ecr2013/C-2245
Background
PHYSIOPATHOLOGY
Renovascular hypertension is produced by decreasing caliber of one or more renal arteries,
which leads to an ischemia stimulating the juxtaglomerular apparatus.
In the long term,
sustained ischemia produces a progressive size reduction with subsequent renal atrophy.
In Table 1 sumarizes the main physiopathological elements.
Often,
the unilateral atherosclerotic stenosis coexists with some degree of renal insufficiency nonischemic condition.
The insufficieny renal conditions the choice of imaging techniques.
Native kidneys:
- Atherosclerosis (80-90%): more common in men older than 55 years,
smokers with atherosclerotic lesions in other vascular territories.
It is typically located in the ostium of the renal artery or proximal to this (Fig. 1a).
- Fibromuscular dysplasia (10-15%): mainly young women.
Usually located in the distal two thirds of the renal artery (Fig. 1b).
- Other causes: renal artery aneurysm,
Takayasu arteritis,
extrinsic compression of the renal artery,
etc (1) (5-10 %).
Transplant kidneys:
- Most of the stenosis are associated with quirurgics surgical problems to at the level of the graft renal artery anastomosis of the graft.
- Ateroma plaques are less common,
and other causes ( Fig. 2 ).
CLINIC
In the Table 2 shows the main clinical data that suggest the existence of renovascular disease.
DEGREE OF STENOSIS AND CLINICAL RELEVANCE
A renal artery stenosis causes significantly hemodynamic deleterious effects when ≥ 70%.
The progression to hemodynamically significantly stenosis is usually associated with new clinical data as poorer control of blood pressure or a sudden deterioration of renal function.
In complete occlusion of the renal artery is important to restore renal perfusion in a few hours,
avoiding loss of function of compromised kidney.
TREATMENT.
The therapeutic management has changed in recent years:
- Atherosclerotic cause: currently,
renal revascularization (angioplasty,
stent) is limited to selected cases ( Table 3 ).
In the majority of situations,
pharmacological treatment is preferred even with a stenosis > 75%.
- Fibromuscular dysplasia and transplanted kidneys: interventional revascularization (angioplasty,
stent) in stenosis > 75%.
- Other causes: depend on the etiology (ex Takayasu's disease may be indicated associate immunosuppressive therapy).
In Renovascular hypertension is very effective the use of drugs that inhibit the renin angiotensin system.
Also in atherosclerotic stenosis must be associated lipid-lowering drugs (statins at high doses).