Renovascular Hypertension

Staci Smith DO

Case Presentation

• CC: dizziness

• HPI:62 yo WM presented to GVH w/ complaints of SOB and dizziness for the past three days. Dizziness occurs w/standing up. No LOC, numbness, or tingling. Positive for history of CVA with right sided upper extremity weakness. Pt’s wife has noticed that bp has been fluctuating.

Case Presentation

Case Presentation

• PMHx:– HTN x 20yrs– CKD 4-5– CVA– PVD– AAA– CAD– L Subclavian stenosis– DMT2 (IR)– L DVT

• PSHx:– GFF– Heart cath – CABG x 4v– IVC filter– Cervical diskectomy – EGD / colonoscopy

Medications

• Aggrenox 200/25 mg two b.i.d

• Allopurinol 100 mg b.i.d• Carvedilol 12.5 mg b.i.d• Clonidine 0.2 mg t.i.d• Ferrous sulfate 325 mg

daily • Finasteride 5 mg daily hs• Flomax 0.4 mg daily hs• Furosemide 80 mg daily• Glyburide 5 mg b.i.d

• Hydralazine 25 mg two tablets t.i.d

• Isosorbide 60 mg daily• Levemir at bedtime• Nexium 40 mg daily• Plavix 75 mg daily• Simvastatin 20 mg q.h.s

Secondary Causes of HTN• Renal Artery Stenosis• Obstructive Sleep Apnea / Obesity• Pheochromocytoma• Thyroid Disease• Cushing’s Syndrome• Hyperaldosteronism• Primary hyperparathyroidism• Congenital Adrenal Hyperplasia• Birth Control • Drugs of Abuse• Caffeine and Diet

Clues to Secondary Causes of Hypertension

• Severe or refractory hypertension• Acute rise in blood pressure over a previously

stable value• Proven age of onset before puberty • Age less than 30 years

– non-obese, non-black patients with a confirmed negative family history of hypertension

When to Suspect Renal Artery Stenosis

• Hypertension before the age of 30 years– negative family history and no other risk

factors • Onset of severe or stage II hypertension after

age 55 yo• Refractory or resistant hypertension

– three agents including a diuretic• Acute rise in blood pressure over a previously

stable baseline in patients

When to Suspect Renal Artery Stenosis

• Unexpected rise in Cr after starting ACE/ ARB• Atrophic kidney size • Flash pulmonary edema or unexplained heart

failure • An abdominal bruit that lateralizes to one side

Causes of Renal Artery Stenosis

• Atherosclerosis• Fibromuscular dysplasia• Cholesterol embolic disease• Acute arterial thrombosis or embolism• Aortic dissection• Renal arterial trauma or aneurysm• Arteriovenous malformation of the renal artery• Vasculitides

Fibromuscular Dysplasia Vs. Atherosclerosis

Pathophysiology

• clinical consequence of renin-angiotensin-aldosterone activation

• occlusion of the renal artery causes ischemia– renin release elevates bp– increased renin levels help in the conversion of

angiotensin I to angiotensin II– causing severe vasoconstriction and aldosterone

release

• presence of a functioning contralateral kidney – determines ultimate cascade of events

Pathophysiology

Pathophysiology

• Two kidneys are out of sync:– ischemic stenotic kidney produces excessive

renin and retains sodium– the comparatively normal kidney continues to

excrete sodium and water to maintain normal volume levels

• End result is systemic hypertension that is renin and angiotensin mediated

Screening and Diagnostic Testing

• Gold standard-renal angiography

• Magnetic resonance angiography

• Computed tomographic angiography

• Duplex Doppler ultrasonography

Screening and Diagnostic Testing

• MR Angiography:– increasingly used as the first-line screening

test – gadolinium during MR imaging

• nephrogenic systemic fibrosis• estimated glomerular filtration rate less than 30

mL/min, avoid gadolinium

MRA of Aorta and Renal Arteries

• Gadolinium enhanced MRA

• Bilateral RAS

Unilateral Renal Artery Stenosis

Fibromuscular Dysplasia

• Beads on a string• Females > Males

Fibromuscular Dysplasia

If GFR less than 30

• risk of radiocontrast nephropathy– Bicarbonate infusion– Mucomyst– IVF

• either spiral CT or arteriography can be performed– preferably digital subtraction arteriography

with iodinated contrast

Clinical Significance

• arteriographic finding of greater than a 75 percent stenosis – in one or both renal arteries– or a 50 percent stenosis with poststenotic

dilatation