HTN &Renal vascular disorders

Ebadur RahmanFRCP (Edin),FRCPI,FASN, Specialty Certificate in Nephrology (UK)MRCP (UK), DIM (UK), DNeph (UK), MmedSciNephrology (UK).

Consultant & clinical tutorDepartment of NephrologyRiyadh Armed Forces Hospital

Definition

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Impact of Hypertension• 50 million individuals in

the United States have hypertension1

• 277,000 deaths annually in US due to hypertension2

1American Association of Clinical Endocrinologists Medical Guidelines For Clinical Practice for the Diagnosis and Treatment of Hypertension. Endocrine Practice, Vol 12 No. 2 March/April 20062National Center for Health Statistics. Health, United States, 2005, with Chartbook on the Health of Americans. Hyattsville, Maryland: 2004. Available at: http://www.cdc.gov/nchs/hus.htm

Consequences of Hypertension

Hypertension

Brain

Heart

Kidney End-stage renal disease

MI, heart failure,sudden death

Stroke, dementia

1. Weir et al. Am J Hypertens 1999;12:205S-213S. 2. Beers MH, Berkow R, eds. The Merck Manual of Diagnosis and Therapy. 17th ed. 1999:1629-1648. 3. Francis CK. In: Izzo JL Jr, Black HR, eds. Hypertension Primer: The Essentials of High Blood Pressure. 2nd ed. 1999:175-176. 4. Hershey LA. In: Izzo JL Jr, Black HR, eds. Hypertension Primer: The Essentials of High Blood Pressure. 2nd ed. 1999:188-189.

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25 years

Admitted with fits BP 160/100

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Diagnosis

• Posterior reversible leuko ephalopathy

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40 years BP 150/80 normal biochemestry

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What to do

• Observe • ACE• Nephrectomy • DIURETICS• ATENOLOL

ACE

More than 80% essential HTN

Renal causes of hypertension (2.5-6%)

• Polycystic kidney disease • Chronic kidney disease • Urinary tract obstruction • Renin-producing tumor • Liddle syndrome

Endocrine cuases 1-2%• Primary hyperaldosteronism • Cushing syndrome • Pheochromocytoma • Congenital adrenal

hyperplasia

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58 y BP 150/100

• Calcium channel blocker • ACE• ARB• DIURETICS• ATENOLOL

• Ace / arb

ModificationApproximate SBP

Reduction(range)

Weight Reduction 5-10 mmHg/10kg

Adopt DASH eating plan 8-14 mmHg

Dietary sodium reduction 2-8 mmHg

Physical activity 4-9 mmHg

Moderation of alcohol consumption

2–4 mmHg

Lifestyle ModificationsLifestyle Modifications

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Resistant hypertension —16% American Heart Association

defined - uncontrolled blood pressurein spite of concurrent use of 3 antihypertensive agents blood pressure is controlled with 4/ 4+ more medications.

• one of the three agents should be a diuretic and all agents should be prescribed at optimal doses

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Pseudoresistant hypertension —20-30%

1-Inaccurate measurement of blood pressure 2-Poor adherence to antihypertensive therapy. 3-White coat hypertension.

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ISOLATED SYSTOLIC HYPERTENSION

• Defined as a systolic BP above 160 mmHg, with a diastolic BP below 90 mmHg .

• ISH mostly occurs – in olderly ( 60 - 75 % )

• ISH – anemia, – hyperthyroidism, – aortic insufficiency, – arteriovenous fistula, – Paget disease of bone .

• ISH is associated with a 2- to 4 fold increase in the risk – MI, LVH, renal dysfunction, stroke.

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Diastolic hypertension — DBP 90+Goal diastolic pressure of 85 to 90 mmHg .

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Importance of systolic & diastolic pressure —

• Among elderly patients, – HIGHER THE the systolic BP- risk coronary heart

disease

• inversely with the diastolic pressure

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MASKED HTN

• NORMAL CLINIC PRESURE BUT ABNORMAL WITH DAILY ACTIVITY

• A 45-year-old man has just been found to have a persistently raised blood pressure. He considers himself a fit and healthy non-smoker and no other abnormalities were found during the examination.

• What investigations you would do?

Investigations for HTN

How often you will screen

The prevalence of renovascular hypertension

• less than 1 % in patients with mild hypertension

• but may be as high as 10 to 40 %– severe, or refractory hypertension

Types of RAS

• Atherosclerosis –– patients over the age of 45 years – involves the aortic orifice or the proximal main renal

artery.– common in patients with diffuse atherosclerosis

• Fibromuscular dysplasia – – fibromuscular dysplasia (FMD) most often affects women

under the age of 50 years– and typically involves the distal main renal artery or the

intrarenal branches

•Diagnosis

Some clinical clues

• A recent or rapid development of severe hypertension.

• sudden development of left ventricular failure (referred to as "flash pulmonary edema")

• Rapidly rising serum creatinine levels- following administration of angiotensin-converting enzyme (ACE) inhibitors or angiotensin II receptor blockers (ARBs).

Magnetic resonance angiography — MR imaging (MR angiography)

• MR angiography had a sensitivity of 100 percent and specificity of 96 percent

Spiral CT scan with CT angiography — Spiral (helical) CT scan with intravenous contrast injec

• Spiral CT scan – sensitivity and specificity for renal artery stenosis

of 98 and 94 percent, respectively..

Dopler

• Peak systolic velocity -specificity of 85 and 92 percent, respectively.

• It is time-consuming (taking up to two hours to perform).

• It is technically difficult, and is highly operator-dependent.

renal vein renin

• measurements are no longer considered suitable for screening patients because of their poor sensitivity and specificity.

Plasma renin activity —

• The baseline plasma renin activity is elevated in only 50 to 80%

• The sensitivity and specificity of the captopril renin test has ranged in different studies from 75 to 100 percent and 60 to 95 percent, respectively

Captopril renogram —

• Oral captopril (25 to 50 mg) is given one hour before the isotope is injected . The efficacy of this test is based upon the typical ACE inhibitor-induced decline in GFR in the stenotic kidney,– accompanied by an equivalent increase in GFR in the contralateral

kidney due to removal of angiotensin II-mediated vasoconstriction.• The net effect is that the difference between the two kidneys

is enhanced.• A marker of glomerular filtration, such as DTPA, or compounds

that are secreted by the proximal tubule, such as hippurate and MAG3, have been used.

• MAG3 more reliable in patients with renal insufficiency

• How ever most centers in US donot do this scan and preffer MRI OR CT ANGIO

Gold standard-angiogram

• Management issues

Three therapeutic options are available

• Medical therapy• Percutaneous angioplasty with or without

stent placement• Surgery

Medical management

The largest trial, ASTRAL, included 806 patients with either unilateral or bilateral atherosclerotic renal artery stenosis who were randomly assigned to either medical therapy alone or medical therapy plus revascularization

• showed no significant difference between the two groups in the rate of progression of the serum creatinine (the primary end point) at a median follow-up of almost three years.

it is generally recommended that the following patients undergo renal artery revascularization

• Those with recent onset hypertension,• younger patients

– less likely to have underlying atherosclerotic disease,– significantly reduce the number of antihypertensive medications.

• Patients whose blood pressure cannot be lowered to the desired goal despite compliance with a reasonable medication regimen.

• Patients who are unable to tolerate antihypertensive• Patients with loss of parenchymal mass from ischemic

nephropathy.

WHICH OF THE FOLLOWING DRUG CAN CAUSE ACUTE RENAL SHUT DOWN IN BILATERAL RAS

• LABETOLOL• AMLODIPINE• NEMODIPINE• NITROPRUSIDE• Ace/arb

WHICH OF THE FOLLOWING DRUG CAN CAUSE ACUTE RENAL SHUT DOWN IN BILATERAL RAS

• LABETOLOL• AMLODIPINE• NEMODIPINE• NITROPRUSIDE• Ace/arb

Surgical revascularization should be

• considered if angioplasty fails• who have multiple small renal arteries, • early primary branching of the main renal

artery, • require aortic reconstruction near the renal

arteries for other indications• aneurysm repair or severe aortoiliac occlusive

disease)

• Thank you