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