高血壓-fibromuscular dysplasia

動脈化生不良 Fibromuscular dysplasia (FMD)

簡介:
  -a non-inflammatory, nonatherosclerotic disorder that leads to arterial stenosis, occlusion, aneurysm, and dissection.
  -部位:
      -最常見: renal & internal carotid arteries,
      -次常見: vertebral, iliac, subclavian, and visceral arteries.
      -nearly in every arterial bed.

  Disease presentation may vary widely, depending upon the arterial segment involved and the severity of disease.
  Common manifestations:
       -hypertension,
       -TIA, stroke,
       -headache, dizziness, tinnitus, and pulsatile tinnitus (abnormal swooshing sound in ears) [1].

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臨床表現:

renal FMD —

  -Hypertension (最常見於 renal artery FMD)

        -A decrease in renal perfusion activates the renin–angiotensin-aldosterone system, which has direct effects on sodium excretion, sympathetic nerve activity, intrarenal prostaglandin concentrations, and nitric oxide production.

        -These ultimately lead to renovascular hypertension.

  *Thus, renal artery FMD should be suspected, particularly in ->
          women (< 50 y/o), in the following settings:
               -Severe or resistant hypertension,
               -Onset of hypertension before the age of 35 years,
               -sudden rise in blood pressure over a previously stable baseline
               -A significant increase in serum Cr (≥ 0.5 to 1 mg/dL) that occurs after (ACEi) or (ARB) in the absence of an excessive reduction in blood pressure (see "Renal effects of ACE inhibitors in hypertension")
               -A systolic-diastolic epigastric bruit

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DDx:

-most commonly mimic the presentation of fibromuscular dysplasia (FMD) are
    -atherosclerotic vascular disease and
    -vasculitis.

■Both atherosclerosis and FMD may cause renal artery stenosis. Patients with atherosclerosis are usually older and have typical cardiovascular risk factors such as dyslipidemia, diabetes mellitus, and a history of tobacco use, whereas individuals with FMD are usually younger and have fewer cardiovascular risk factors [19]. However, given that FMD can occur in older patients, age alone does not exclude the diagnosis.
Atherosclerosis usually involves the ostial or proximal segments of the arteries, whereas FMD involves the middle or distal segments. In addition, the string of beads appearance is unique to FMD.
■Multi-system involvement is observed in both vasculitis and FMD. Unlike patients with a vasculitic process, those with FMD generally will not have associated anemia, thrombocytopenia, or abnormalities of acute phase reactants (eg, erythrocyte sedimentation rate or C-reactive protein) given that it is a non-inflammatory process. An exception might be in the setting of an acute infarction.
■Other possibilities that may be initially considered before renal artery FMD is diagnosed include
      -primary hypertension (formerly called "essential" hypertension) and
      -any of the potential causes of secondary hypertension,
      -pulmonary edema due to cardiovascular disease, and
      -slowly progressive CKD.
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診斷 —

    -the diagnosis is confirmed most frequently by:

          -CTA

          -MRA or

          -duplex ultrasonography, and

          -catheter-based digital subtraction angiography (DSA) (較少用)

 

DSA
    -the reference standard.
    -The performance of noninvasive techniques varies depending upon the involved vascular bed and the expertise of a given institution.
    -extracranial cerebrovascular FMD can be diagnosed with CTA, MRA, or duplex ultrasonography, while
    -mesenteric FMD is usually diagnosed with CTA.

Patients suspected of having FMD should
    -first undergo a noninvasive imaging test (such as duplex ultrasound or CTA) to search for FMD.
    -The choice of test should be based upon local expertise.
    -If the noninvasive test is inconclusive, the patient should undergo DSA provided that the pretest probability of FMD remains high and that an intervention would be performed if FMD were to be diagnosed [19].

Imaging techniques —
   -The gold standard for evaluating FMD in the renal artery and other vascular beds is catheter-based DSA, which improves visualization of the arteries by eliminating background soft tissue and bone [19]. However, noninvasive imaging techniques are usually sufficient, and therefore DSA is not commonly performed. The angiographic appearances of the different pathologic lesions are as follows:

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結論及建議:

 •It is more common among women and, while initially thought to only occur in the young, may occur at any age.
 •The most often involved arteries are the renal (70 %) and internal carotid and vertebral arteries (約65 %), and less often are the iliac, subclavian, and visceral arteries. (See 'Epidemiology' above.)

•The pathogenesis is uncertain,  genetic factors, hormonal influence, and ischemia may contribute. (See 'Pathogenesis' above.)

•The most common manifestations are hypertension, headache, dizziness, tinnitus, transient ischemic attack, and stroke, but other manifestations may occur, depending upon the arterial segment involved and the severity of disease. (See 'Clinical manifestations' above.)

•The diagnosis of renal artery FMD should be suspected in patients with severe or resistant hypertension and an increase in serum creatinine after initiation of an angiotensin-converting enzyme (ACE) inhibitor or angiotensin II receptor blocker (ARB) (particularly in women under the age of 50), onset of hypertension before the age of 35 years, and a systolic-diastolic epigastric bruit.

 •The conditions that most commonly mimic FMD are atherosclerotic vascular disease and vasculitis. (See 'Differential diagnosis' above.)

 •In patients in whom there is a suspicion for renovascular hypertension, a noninvasive imaging test (such as duplex ultrasound or CTA) should be performed first. The choice of test should be based upon local expertise. If noninvasive tests are inconclusive and pretest probability of FMD is high, the patient should undergo catheter-based digital subtraction arteriography. (See 'Imaging techniques' above.)

 •For patients treated medically, we suggest
                -following BP and serum Cr every 3-4 months, and
                -腎超: kidney size every 6 to 12 months. (See 'Monitoring disease progression' above)