Renal artery stenosis

Renal artery stenosis Dr. Alexander Woywodt Consultant Renal Physician, Royal Preston Hospital Preston, 31.10.2007

Menu anatomy of the renal arteries diseases of the large renal arteries atherosclerotic renal artery stenosis diagnostic approaches treatment other diseases of the large renal arteries

Anatomy Anatomy of of the the renal renal arteries arteries two two main main arteries arteries

Anatomy of the renal arteries Right renal artery Left renal artery

Anatomy of the renal arteries variants: precaval right renal artery (5%) [Radiology 2004;230:429-433 ]. supernumerary and early branching arteries in 16% and 21%, respectively (upper pole or lower pole arteries) [AJR 2007 188(1):105] multiple supernumerary arteries associated anomalies

Anatomy of the renal arteries

Diseases of the large renal vessels atherosclerotic renal artery stenosis fibromuscular dysplasia (FMD) obstruction of the renal arteries due to aortic dissection obstruction of the renal arteries after interventional stenting of the abdominal aorta for aneurysm renal artery embolism

Atherosclerotic renal artery stenosis

Natural history of atherosclerotic renal artery stenosis

A forefather of nephrology and hypertension Speculated that pale hypertension is mediated by factors secreted by the kidney This was later proven by Goldblatt Volhard also pioneered the saltfree diet A man of varied interests Franz Volhard 1872-1950

First experiments into renovascular hypertension Injection into other dogs Hypertension Hypertension Wolf G, Franz Volhard and his students tortuous road to hypertension. KI 57: 2156 92000)

Renin angiotensin aldosterone system Uptodate

Pathophysiology of atherosclerotic renal artery stenosis

Renal artery stenosis prevalence and diagnostic clues cause of end-stage renal failure in 8 to 55% of patients 14-29% of patients with ischemic heart disease 38% of patients with abdominal aortic aneurysm 39% of patients with peripheral vascular disease clinically evident vascular disease elsewhere blood pressure not controlled with three or more drugs abdominal bruit (maybe worthwhile to check lumbar area) kidneys of different size rise in creatinine and/or hyperkalemia after ACE inhibitor flash pulmonary edema

Diagnostic approaches clinical index of suspicion ultrasound angiography CT angiography magnetic resonance angiography

Ultrasound diagnosis of renal artery stenosis Hieronymus Bosch: The impostor. Copy in Saint-Germain-en-Laye (original lost)

Ultrasound diagnosis of renal artery stenosis Direct signs: Increased velocity at at site of of stenosis, at at least in in excess of of 180 cm/sec Insonation Angle R-RA x Aorta L-RA V -400/96 cm/sec V 100/27 cm/sec X In sonation Angle R ight Kidney within stenosis distal renal artery Indirect signs: Delayed acceleration time, Low renal resistive index

Renal resistive index RI=([1 - end-diastolic velocity divided by peak systolic velocity]) Depends on skilled operator Also affected by atrial fibrillation, fever, aortic stenosis etc.

Renal resistive index RI = 72 RI = 86 No microvascular disease Advanced microvascular disease RI=([1 - end-diastolic velocity divided by peak systolic velocity])

Hypertensive/vascular nephropathy

Issues with ultrasound diagnosis of renal artery stenosis non-invasive, no no radiocontrast highly highlydependent on on experience and and skills skills on on average, absorbs highly highlyskilled skilleddoctor doctorfor for45 45 min. min. 30 min 45 min 60 min

Angiography and magnetic resonance angiography From UpToDate (MR scanning currently not recommended with GFR < 30 ml/min)

Medical treatment risk factors should be addressed diabetes management, smoking cessation ASS, LDL <100 mg/dl antihypertensive therapy including ARB // ACE inhibitor these were once regarded as contraindicated - no longer the case great care must be taken (hyperkalemia) particularly dangerous: combination with spironolactone and NSAIDS bilateral renal atery stenosis possibly contraindication ARBs possibly preferable (no evidence)

Renal artery intervention Gruentzig A. et al., Treatment of renovascular hypertension with percutaneous transluminal dilatation of a renal-artery stenosis. Lancet 1: 801-802 (1978)

Renal artery intervention is not risk-free Fatal bleed after perforation with guide wire Journal of Vascular and Interventional Radiology 15:985-987 (2004)

Intervention or medical treatment Radermacher et al., N Engl J Med, Vol. 344, No. 6, February 8, 2001

Treatment of renal artery stenosis: Medical treatment vs. stent medical stenting old age very calcified atherosclerosis advanced renal failure (GFR < 30, changes on ultrasound) high renal resistive index? bilateral stenosis flash pulmonary edema stenosis > 65% with RI<0.8 BP uncontrolled on 3 drugs low renal resistive index?

Treatment of renal artery stenosis

Renal artery intervention - current dilemma Available evidence does not clearly support one treatment approach over another for atherosclerotic renal artery stenosis. Balk E et al. Ann Intern Med. 2006 145(12):901-12. Hieronymus Bosch: The ship of fools. Louvre, Paris

Renal artery intervention - current dilemma Srivastava and Beevers, J Hum Hypertens 2007: 21: 507

Treatment of renal artery stenosis: ASTRAL study 750-1000 patients with renovascular disease 500 medical treatment / 500 intervention Progression of renal failure as endpoint

Fibromuscular dysplasia (FMD) inborn error of vascular structure usually younger female patients with positive family history often bilateral and other large arteries affected no occlusion string of beads appearance amenable to stenting (very) From UpToDate

Obstruction of the renal arteries due to aortic dissection rarely the leading symptom of aortic dissection often found on angiography flank pain, acute renal failure, haematuria Woywodt et al., Nephrology, Dialysis, Transplantation 15(4): 544-546 (2000)

Obstruction of the renal arteries after aortic stenting Cotroneo et al., Radiol Med (2007) 112:252 263

Embolic renal artery occlusion sudden onset of flank pain, often in atrial fibrillation fever nausea, vomiting LDH and D-Dimer abnormal ultrasound with colour duplex, CT thrombolysis / surgery / heparin Fort et al., Nephrol Dial Transplant (1996) 11: 1843-1845

Messages Renal artery stenosis is isnot rare Older vascular patients vs. young females with a family history of hypertension Differences in in renal size, abdominal bruit and clinical vascular disease Controversies in in diagnostic approach and management