What is the natural history of atheromatous stenoses of the renal arteries?
The prognosis is primarily conditioned by the frequency of cardiovascular events that occur in the context of atheromatous disease. In a population of patients with renal artery stenosis, 40% will have a cardiovascular event and only 8% will have terminal renal insufficiency.
The spontaneous risk of thrombosis on an atheromatous stenosis of a renal artery is 3%.
Independently of these stenoses, we must take into consideration the atheromatous renal micro-vascular disease (nephro-angiosclerosis), the evaluation of which will condition the benefit of renal revascularization. In practice, there is no benefit of dilating a kidney severely affected with nephro-angiosclerosis.
How to detect and « bilant » an atheromatous stenosis of the renal artery?
The first-line biological assessment is the realization of a blood ionogram and a clearance of serum creatinine, a proteinuria of 24 hours (a proteinuria> 1 g / l shows an advanced renal involvement for which a possible revascularization will have a benefit modest).
The first examination to be performed is a renal arterial echo-doppler.
This examination describes:
- In doppler mode the systolic peak> 3m / seconds which is an excellent sign to evoke a tight stenosis.
- There are other indications for exploring kidney damage by nephro-angiosclerosis: kidney height <8 cm, cortico-medullary index <1, resistance index> 0.8. When these latter elements are combined, the volume of functional renal parenchyma to be reperfused is small, there is a modest benefit to the dilation of a possible stenosis.
In second intention, one realizes either an angio scanner or an angio MRI to confirm the diagnosis. They also make it possible to anticipate the accessibility to the stenosis if there is indication of dilatation.
Arteriography, scintigraphy are very limited indications examinations.
The objective of the assessment is to confirm the stenosis and at the same time to evaluate the functionality of the kidney to predict the benefit or not of a revascularization. Dilating a non-functioning or functional kidney does not in fact benefit the patient.
When to seek an atheromatous stenosis of the renal arteries?
– Severe HTA (> 180mmHg / 110mmHg) after 55 years.
- HTA resistant to 3 antihypertensive treatments.
- HTA rapidly progressive.
- Aggravation of renal function after introduction of an I.E.C.
- Unexplained renal atrophy or difference in diameter between the two kidneys of more than 15mm.
- OAP of sudden onset and undetermined aetiology.
- Unexplained renal insufficiency.
- HTA + occlusive arterial lesions in at least two territories (carotid, lower limbs, coronary …).
What treatment to introduce before the discovery of an atheromatous stenosis of the renal artery?
In the context of atheromatous pathology the patient should benefit from the following measures:
– Weight control.
– Blood glucose control.
– Control of dyslipidemia.
– Smoking cessation.
– Control of blood pressure with objective <140mmHg / 90mmHg.
– Physical activity.
– Introduction of a STATINE and ANTIAGREGANT PLAQUETTAIRE (aspirin) in the context of secondary prevention of cardiovascular event.
– The I.E.C. Seem to have a benefit both in secondary prevention of cardiovascular events and in nephronic protection.
However, I.E.C are contraindicated if bilateral stenosis or stenosis on single kidney.
What are the current indications for revascularization?
- Asymptomatic patients: Revascularization is considered only in the context of nephronic protection. It is therefore justified in patients with long life expectancy and particularly in the single kidneys.
- In symptomatic patients:
- –HTA resistant to medical treatment and / or renal insufficiency: The benefit of revascularization of stenoses of more than 70% is currently controversial and therefore suggests a very rigorous evaluation of the viability of the renal parenchyma with To propose a revascularization.
- –Renal failure rapidly progressive, acute renal failure after introduction of I.E.C., OAP « flash », malignant hypertension. In these cases, the discovery of an atheromatous stenosis of the tight renal artery leads to a revascularization.
What are the different revascularizations?
Endovascular techniques (dilation), which are usually the first-line techniques.
Conventional surgical techniques (bypass surgery, endarterectomy …), the indications of which are more rare.
Sources:
French College of Vascular Surgery: http://www.cfcv.fr/reperes.htm
European Society of Cardiology: http://eurheartj.oxfordjournals.org/content/ehj/32/22/2851.full.pdf