What are the causes of a renal artery infarct?

Causes of Renal Artery Infarct

Renal artery infarction results from three primary mechanisms: embolic events (predominantly cardiogenic), primary renal artery lesions (including atherosclerosis, dissection, and fibromuscular dysplasia), and thrombophilic conditions, with cardiogenic embolism being the most common cause overall.

Primary Etiologic Categories

Embolic Causes (Most Common Overall)

• Cardiogenic embolism accounts for approximately 55.7% of renal infarctions, making it the single most important cause 1
• Cardiac sources include atrial fibrillation with thrombus formation, valvular heart disease (particularly aortic and tricuspid valvulopathy), and recent myocardial infarction 2, 3
• Paradoxical embolism through patent foramen ovale can cause renal infarction, though this represents a small minority of cases 4
• The embolic mechanism typically involves thrombus formation in the heart with subsequent embolization to the renal arterial circulation 5

Primary Renal Artery Lesions (81.2% in Specialized Series)

In vascular specialty centers, renal artery lesions themselves are the predominant cause (81.2% of cases), emphasizing the importance of comprehensive arterial evaluation 6:

• Atherosclerotic disease represents 34.4% of renal artery lesions and approximately 90% of renovascular stenotic lesions overall 4, 6

  • Typically affects the aorto-ostial segment and proximal 1 cm of the main renal artery 4
  • Often part of systemic atherosclerosis involving coronary, cerebral, and peripheral arteries 4

• Dissecting hematoma accounts for 23.2% of renal artery lesions 6

  • Can occur spontaneously or following trauma 4

• Fibromuscular dysplasia (FMD) represents 19.2% of renal artery lesions and is the second most common cause of renal artery stenosis overall 4, 6

  • Characteristically involves the middle and distal two-thirds of the main renal artery 4
  • Most commonly presents in young women aged 25-50 years 4
  • Medial fibroplasia accounts for 80-85% of FMD cases 4

Thrombophilic Conditions

• Hypercoagulable states account for approximately 5.9% of renal infarctions 6
• Include inherited and acquired thrombophilias that predispose to in-situ thrombosis 1

Additional Causes

The ACC/AHA guidelines identify multiple other etiologies 4:

• Renal artery aneurysms can cause infarction through thrombosis or distal embolization 4
• Takayasu's arteritis and other vasculitides 4
• Atheroemboli from proximal aortic disease 4
• Trauma including direct injury, lithotripsy, or surgical complications 4
• Arteriovenous malformations or fistulas 4
• Neurofibromatosis and Williams syndrome 4
• Prior abdominal radiation therapy 4
• Retroperitoneal fibrosis causing external compression (rare) 4

Idiopathic Cases

• Approximately 3.8-30.1% of cases remain idiopathic despite thorough evaluation, with variation depending on the comprehensiveness of vascular imaging performed 6, 1
• The wide range in idiopathic cases (3.8% in specialized vascular centers vs. 30.1% in general hospitals) underscores the critical importance of extensive arterial exploration to identify underlying vascular disease 6

Clinical Context

• Both right and left kidneys are equally affected 6
• Renal artery stenosis is found in only 1.5% of acute kidney injury cases, though it may not be the causative factor 4
• The condition should be suspected in patients with sudden-onset abdominal or flank pain refractory to analgesics, especially with history of embolism, recent surgery, or trauma 2