renovascular hypertension

RENOVASCULAR HYPERTENSION:

RENOVASCULAR HYPERTENSION Dr P.M.Sohal (M.D.Medicine;D.M.Nephrology) PGI(CHD) CONSULTANT NEPHROLOGIST LUDHIANA MEDICITI

Renovascular Hypertension:

Renovascular hypertension is chronically raised blood pressure due to a significant renal artery stenosis, which improves after correction of the stenosis Significant means >75% narrowing on angiography. Diagnosis can only be confirmed retrospectly after correction of stenosis. Renovascular Hypertension

Epidemiology :

Epidemiology Prevalence in the unselected , hypertensive population is not precisely known; estimates vary widely between well below 1 and 4 per cent. Atherosclerotic renal artery stenosis often coexists with peripheral vascular and aortic disease. 3698 patients with peripheral or coronary atherosclerosis, the prevalence of unsuspected renal artery stenosis was 23 per cent

Clinical features favouring RVH:

Clinical features favouring RVH Accelerated, treatment-refractory, or malignant hypertension Hypertension with peripheral vascular occlusive disease, with coronary artery disease, or with other signs of generalized arteriosclerosis Moderate to severe hypertension beginning before the age of 30 or after the age of 50 Sudden worsening of hypertension or renal function Decrease of glomerular filtration rate with inhibition of the renin system Hypertension with unexplained renal failure Unilaterally small kidney Abdominal bruits Flash pulmonary edema.

Common Causes Include:-:

Common Causes Include:- Atherosclerosis ( ca. 75% of cases) Fibromuscular dysplasia ( ca. 15% of cases)

Other rare causes are:- :

Other rare causes are:- Dissecting aneurysms of the aorta Dissecting aneurysms of the renal artery Arteritis (e.g. Takayashu's arteritis) Coarctation of the aorta Renal thrombosis and embolism Abdominal trauma with intimal tears Arteriovenous fistulas External compression by tumours After renal transplantation After radiation therapy von Recklinghausen's disease Angiomas

Pathological and radiological aspects:

Pathological and radiological aspects Atherosclerotic stenosis Stenosis is located in the proximal 2–3 cm. Ostial involvement three-fourths. The lesions are commonly bilateral in two-thirds of 109 cases. 30 per cent of cases had only one functioning kidney. There is no agreement as to whether atherosclerotic lesions predominantly occur on the left or on the right. Segmental lesions were seen in 10 per cent of patients.

Fibromuscular dysplasia:

Fibromuscular dysplasia The natural history is not well delineated most patients are invasively treated. In one study of 42 patients, all had progressive disease 50 per cent of the patients were male Lesions were bilateral in 79 per cent. A decrease in the size of the kidney of more than 0.5 cm occurred in 62 per cent; total occlusion was seen in one-fourth.

Radiological Features:

Radiological Features Renal artery aneurysm combined with fibromuscular disease.

DISSECTION OF RENAL ARTERY:

DISSECTION OF RENAL ARTERY

Atherosclerotic renovascular disease :

Atherosclerotic renovascular disease Progression of atherosclerotic renovascular stenosis is relentless . Original n No progression (%) Progression Progression luminal narrowing(%) without total occlusion toocclusion(%) 75–99 18 61 — 39 50–75 30 53 37 10 <50 78 69 26 5 ( Tollefson and Ernst 1991 ; Guzman et al . 1994 ; Zierler et al . 1994)

Diagnosis :

Diagnosis Clinical characteristics ( Working Group on Renovascular Hypertension 1987 ) Abdominal or flank bruits;. The presence of a diastolic component greatly increases the likelihood of renal artery stenosis. The blood pressure level above 160 and 100 mmHg, respectively, despite antihypertensive therapy was associated with a 30 per cent prevalence of renal artery stenosis. Recent onset, disease after the age of 50 years Negative family history of hypertension Severe retinopathy than those with essential hypertension. Proteinuria, which may reach nephrotic range, was also more prevalent in renovascular than in essential hypertension. atherosclerotic renovascular hypertension typically have signs and symptoms of atherosclerosis in other vascular beds. Recurrent sudden or 'flash' pulmonary oedema may also be a presenting symptom in patients with renovascular hypertension; most also have impaired renal function ( Missouris et al . 1993 ).

Natural History:

Natural History Atherosclerotic renovascular disease independent predictor for mortality. Risk factors for excess CVS mortality:- Widespread atherosclerosis, Severe hypertension Increased activity of the renin–angiotensin system Accelerated atherogenesis Left ventricular hypertrophy.

Management Approach:

Management Approach

Management:

Management The choice depends on Age Control of blood pressure Renal function Concomitant diseases Operative risk Type, extent and site of stenosis Renal vein renin tests Local surgical or angiological experience Preference of the patient and the physician.

Medical management:

Medical management Trend towards conservative treatment ( Plouin et al . 1998 ; Webster et al . 1998 ; van Jaarsveld et al . 2000 ). Medical care has to consider the high cardiovascular mortality, Statins and antiplatelet agents as well as antihypertensive drugs should be provided Smoking should be discouraged. Effect of statins and antiplatelet drugs on the progression of renal artery stenosis renovascular disease must be taken into account. (opinion) With unilateral disease, blood pressure is negatively correlated with sodium balance ( Davies et al . 1983 ). Diuretics to be used with caution Does not apply to bilateral disease or to single kidneys.

Medical management contd :-:

Medical management contd :- Even with good control of blood pressure In fact, roughly 20 per cent of patients with renal artery stenosis show a decline of GFR in the affected kidney with the administration of ACE inhibitors with wide interindividual variability. Patients with renovascular, a substantial number of patients will exhibit a decrease of renal mass with medical therapy ( Dean et al . 1991 ; Guzman et al . 1994 ; Zierler et al . 1994 ; Caps et al . 1998 ). Medical treatment may be preferred even in patients with high-grade renal artery stenosis ( Tullis et al . 1999 ). Long-term follow-up of patients ,the development of terminal renal failure is rare ( Leertouwer et al . 2001 ).

Medical management contd :-:

Medical management contd :- InhibiItors of the renin–angiotensin system are not the first choice, however they should be used, with caution, when blood pressure is not normalized because they are very effective antihypertensive agents with renovascular hypertension ( Franklin and Smith 1985;Van de Ven et al . 1998 ). In a trial comparing classical antihypertensive drugs or to ACE inhibitors. Serum creatinine increased somewhat more on ACE inhibitors, but blood pressure was much better controlled ( Franklin and Smith 1985 ). Reno vascular hypertension frequently require long-acting antihypertensive agents .

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PERCUTANIOUS TRANSLUMINAL RENAL ANGIOPLASTY PTRA started by (Dotter and Indkins (1964) and Grüntzig et al . (1978 ). A dvocated for the treatment of patients who had complications or were unlikely to survive surgery ( Weinberger et al . 1979 ). When compared with surgery, PTRA offers the following advantages: (a) brief hospitalization; (b) lower cost; (c) can be used in those with poor operative risk; (d) low mortality and relatively low morbidity associated with the technique; (e) ready availability in hospitals with departments of angiography.

PTRA Contd :-:

Major complications, even in experienced departments, occurred in 2–10 per cent of PTRAs; the death rate ranged from 0 to 3 per cent (mean < 1 per cent) ( Mahler et al . 1986 ). The major complications are listed in Table Occlusion of renal artery Cholesterol embolism (to renal or peripheral arteries) Puncture-site haemorrhage and aneurysm Dissection of renal or angiographic access artery or of aorta Spasm of renal artery with possible partial infarction (apparently a problem of guide-wire techniques) Renal artery perforation Cerebral or myocardial infarction Arterial embolism Haemorrhagic shock Infections Thyrotoxicosis (resulting from exposure to iodine) Death PTRA Contd :-

Results of PTRA:

Results of PTRA

PTRA V/S MEDICAL THERAPY:

PTRA V/S MEDICAL THERAPY There are few trials to draw conclusions those available lack standardization regarding BP level at entry. Unilateral disease had no significant difference in BP control over 6 months(Webster 1998). Greater BP benefit after PTRA in bilateral disease 27% crossed to PTRA group for refractory HTN(Plouin1998) DRASTIC trial (van jarsveld 2000) no BP difference in 2 groups 44% crossed over to PTRA group after 3 months Concluded that patients can be assigned to medical therapy and to review once therapy fails after 3 months

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Indications of Thrombo-Enderectomy With Reconstruction Ostial stenosis of the renal artery Simultaneous reconstruction of the aortoiliac vasculature Severe contrast-media hypersensitivity Renal artery aneurysm Renal artery aneurysm combined with stenosis Renal artery occlusion Renal artery rupture Re-stenosis after PTRA or unsuccessful PTRA Renal artery stenosis secondary to kinking Small non-functioning kidney (nephrectomy) Peripheral multifocal stenosis

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Results of reconstructive surgery

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