Fibromuscular Dysplasia Workup
- Author: James A Wilson, MD, MSc, FRCPC; Chief Editor: Helmi L Lutsep, MD more...
Although usually nonproductive, routine laboratory investigations may show renal impairment (eg, with high creatinine or BUN levels).
For a more focused analysis of imaging studies in FMD, please see Fibromuscular Dysplasia (Carotid Artery).
The history of stroke or transient ischemic attack in a young individual or a subarachnoid hemorrhage in a person of any age should prompt imaging of the cerebrovascular system. Further, any individual known to have FMD (eg, renal disease detected) should undergo cerebrovascular imaging to assess for craniocervical involvement and aneurysms.
Conventional angiography remains the criterion standard to detect FMD and its associated vascular lesions (eg, aneurysms, dissections). (See images below.)
FMD lesions typically show a beading pattern. With the most common subtype of FMD, medial fibroplasias, the dilated arterial segments are often larger in diameter than the original vessel. This is not the case with perimedial fibroplasias, in which the beads are up to, but not greater than, the caliber of the original vessel. On the other hand, the intimal fibroplasia and the medial hyperplasia subtypes tend to show long tubular stenoses.
In the internal carotid arteries, these lesions are usually extracranial at the C1-2 level. Stenoses associated with arterial bifurcations, such as at the bifurcation of the common carotid, are more frequently atherosclerotic in nature. Four-vessel angiography should be performed because of the high incidence of multiple vessel involvement.
In 1986, Luscher et al identified 24 patients with cerebrovascular FMD and found that 17% had involvement of the vertebral arteries, 17% had brachiocephalic or subclavian involvement, and 4% had basilar artery disease.
Conventional cerebrovascular ultrasonography is unlikely to depict the carotid lesions of FMD because they are typically sufficiently distal to the carotid bifurcation so as to avoid detection by standard carotid duplex investigation.
Submandibular insonation with a transcranial Doppler probe directed at the high cervical segments can be used to investigate the distal cervical artery and has moderate sensitivity for detecting FMD.
Doppler scanning of the vertebrobasilar system may reveal reversal of flow (including subclavian steal), but it is not in any way sensitive or specific for FMD.
To the authors' knowledge, no large studies have been conducted to assess the sensitivity or specificity of CT angiography (CTA), time-of-flight (TOF) magnetic resonance angiography (MRA), or contrast-enhanced MRA (CE MRA) in the diagnosis of craniocervical FMD. However, these modalities, especially CTA and CE MRA, can show surprising vascular detail and may be sufficiently sensitive for the confident detection of FMD. Due to the risk of conventional angiography, there is certainly a need to identify comparably sensitive noninvasive imaging techniques. Fortunately, we have some clues from the renal literature that the above noninvasive techniques could be comparable.
CTA is continuously improving in resolution and may be used to detect the stenosis associated with FMD, but only recent-generation CTA equipment reliably shows sufficient detail to identify the classic string of beads pattern of most FMD cases. de Monye advocates the use of CTA as a noninvasive modality to diagnose FMD, albeit with only a series of 2 patients. Regarding FMD of the renal arteries, the sensitivity of CTA has been compared directly with conventional angiography. In their series of 21 patients with 40 total lesions identified on conventional angiography, all lesions were identified using several modalities of CTA (multiplanar reformatted images, maximum intensity projections, and shaded-surface display). Suspecting that CTA of the carotid arteries shares similar sensitivity to conventional angiography in identifying craniocervical FMD would be reasonable.
Findings on TOF MRA often suggest vessel stenoses, but this study has insufficient resolution to demonstrate a string-of-beads pattern suggestive of FMD.
Contrast-enhanced MRA will likely perform better than TOF MRA, but this has not yet been studied in detail regarding craniocervical FMD. However, similar to CTA, the renal literature has looked at FMD of the renal arteries using CE MRA. In a series of 25 patients, Willoteaux found the sensitivity and specificity of CE MRA in renal FMD to be 97% and 93% respectively. They found 68% sensitivity in diagnosing stenosis, 95% in identifying the string of pearls, and 100% sensitivity in identifying an aneurysm. Thus, although CE MRA in craniocervical FMD has not specifically been assessed, it is likely that this modality is reasonably sensitive as compared with the more invasive criterion standard.
Conventional CT scanning and MRI may be useful in finding ischemic strokes caused by arterial dissection or the FMD lesions themselves. These modalities can also be useful in detecting subarachnoid hemorrhage.
CTA and MRA can often detect aneurysms greater than about 0.3 cm.
Pathologically, FMD is a nonatherosclerotic noninflammatory narrowing of medium-sized arteries characterized by fibrodysplastic changes. In 1979, Bragin and Cherkasov described the ultrastructural changes that occur in FMD as smooth muscle assuming fibroblastic characteristics. FMD has been classified according to the arterial wall layer that is predominantly affected.
The pathologic classification of FMD is as follows:[10, 11, 12]
See the list below:
This accounts for fewer than 10% of all cases of renal FMD.
Collagen deposition occurs in the intima of the vessels.
Internal elastic lamina may be disrupted.
The lumen may be concentrically narrowed in a relatively short region, causing a ringlike stenosis on angiography, or it may be narrowed over a longer region as a smooth tubular stenosis.
Medial fibroplasia (3 subtypes)
This accounts for 80% of renal cases and most carotid cases.
Regions of thick, fibrodysplastic, collagenized tunica media alternate with regions of thinned media.
The result is the classic string-of-beads appearance on angiography.
This accounts for 10-15% of all renal cases of FMD.
Patchy collagen deposition is observed in the outer media without disruption of the external elastic lamina.
This subtype can also result in the string-of-beads appearance on angiography, but the beads are not dilated to a larger diameter than that of the original vessel.
This accounts for 1-2% of all renal cases of FMD.
True smooth muscle concentric hyperplasia without fibrotic changes is noted.
The result is a smooth stenosis on radiographic study.
See the list below:
This form results in fewer than 1% of all renal cases of FMD.
Dense collagen replaces the normally loose connective tissue of the adventitia.
The percentage occurrence of each type of FMD is largely based on findings from large renal studies and may not reflect the distribution of FMD types in carotid disease. In fact, the medial dysplasia type may be even more predominant when carotid FMD is considered alone.
No formal staging system exists for FMD, although 4-vessel angiography of the cerebrovasculature is used to identify the extent of the craniocervical disease and the presence of comorbid dissections and aneurysms.
Luscher TF, Lie JT, Stanson AW, et al. Arterial fibromuscular dysplasia. Mayo Clin Proc. 1987 Oct. 62(10):931-52. [Medline].
Gray GH, Young JR, Olin JW. Miscellaneous arterial diseases. Young JR, Olin JW, Bartholomew J, eds. Peripheral Vascular Diseases. 2nd ed. St Louis: Mosby-Yearbook; 1996. 425-40.
James TN. Morphologic characteristics and functional significance of focal fibromuscular dysplasia of small coronary arteries. Am J Cardiol. 1990 Apr 3. 65(14):12G-22G. [Medline].
Campman SC, Holmes JF, Sokolove PE, et al. Pulmonary arterial fibromuscular dysplasia: a rare cause of fulminant lunghemorrhage. Am J Forensic Med Pathol. 2000 Mar. 21(1):69-73. [Medline].
Maresi E, Becchina G, Ottoveggio G, et al. Arrhythmic sudden cardiac death in a 3-year-old child with intimal fibroplasia of coronary arteries, aorta, and its branches. Cardiovasc Pathol. 2001 Jan-Feb. 10(1):43-8. [Medline].
Luscher TF, Keller HM, Imhof HG, et al. Fibromuscular hyperplasia: extension of the disease and therapeutic outcome. Results of the University Hospital Zurich Cooperative Study on Fibromuscular Hyperplasia. Nephron. 1986. 44 Suppl 1:109-14. [Medline].
Hill LD, Antonius JI. Arterial dysplasia: an important surgical lesion. Arch Surg. 1965 Apr. 90:585-95. [Medline].
Heffelfinger MJ, Holley KE, Havrison EG. Arterial fibromuscular dysplasia studied at autopsy [abstract]. Am J Clin Pathol. 1970. 54:274.
Schievink WI, Bjornsson J. Fibromuscular dysplasia of the internal carotid artery: a clinicopathological study. Clin Neuropathol. 1996 Jan-Feb. 15(1):2-6. [Medline].
Harrison EG Jr, McCormack LJ. Pathologic classification of renal arterial disease in renovascular hypertension. Mayo Clin Proc. 1971 Mar. 46(3):161-7. [Medline].
Stanley JC, Gewertz BL, Bove EL, et al. Arterial fibrodysplasia. Histopathologic character and current etiologic concepts. Arch Surg. 1975 May. 110(5):561-6. [Medline].
Begelman SM, Olin JW. Fibromuscular dysplasia. Curr Opin Rheumatol. 2000 Jan. 12(1):41-7. [Medline].
Reiher L, Pfeiffer T, Sandmann W. Long-term results after surgical reconstruction for renal artery fibromuscular dysplasia. Eur J Vasc Endovasc Surg. 2000 Dec. 20(6):556-9. [Medline].
Mettinger KL, Ericson K. Fibromuscular dysplasia and the brain. I. Observations on angiographic, clinical and genetic characteristics. Stroke. 1982 Jan-Feb. 13(1):46-52. [Medline].
Cloft HJ, Kallmes DF, Kallmes MH, et al. Prevalence of cerebral aneurysms in patients with fibromuscular dysplasia:a reassessment. J Neurosurg. 1998 Mar. 88(3):436-40. [Medline].
Arunodaya GR, Vani S, Shankar SK, et al. Fibromuscular dysplasia with dissection of basilar artery presenting as "locked-in-syndrome". Neurology. 1997 Jun. 48(6):1605-8. [Medline].
Eachempati SR, Sebastian MW, Reed RL 2nd. Posttraumatic bilateral carotid artery and right vertebral artery dissections in a patient with fibromuscular dysplasia: case report and review of the literature. J Trauma. 1998 Feb. 44(2):406-9. [Medline].
Rushton AR. The genetics of fibromuscular dysplasia. Arch Intern Med. 1980 Feb. 140(2):233-6. [Medline].
Bigazzi R, Bianchi S, Quilici N, et al. Bilateral fibromuscular dysplasia in identical twins. Am J Kidney Dis. 1998 Dec. 32(6):E4. [Medline].
Tromp G, Wu Y, Prockop DJ, et al. Sequencing of cDNA from 50 unrelated patients reveals that mutations inthe triple-helical domain of type III procollagen are an infrequent causeof aortic aneurysms. J Clin Invest. 1993 Jun. 91(6):2539-45. [Medline].
McKusick VA. Heritable Disorders of Connective Tissue. 4th ed. St Louis: Mosby-Yearbook; 1972. 382-6.
Schievink WI, Meyer FB, Parisi JE, Wijdicks EF. Fibromuscular dysplasia of the internal carotid artery associated with alpha1-antitrypsin deficiency. Neurosurgery. 1998 Aug. 43(2):229-33; discussion 233-4. [Medline].
de Bray JM, Marc G, Pautot V, Vielle B, Pasco A, Lhoste P. Fibromuscular dysplasia may herald symptomatic recurrence of cervical artery dissection. Cerebrovasc Dis. 2007. 23(5-6):448-52. [Medline].
Lee EK, Hecht ST, Lie JT. Multiple intracranial and systemic aneurysms associated withinfantile-onset arterial fibromuscular dysplasia. Neurology. 1998 Mar. 50(3):828-9. [Medline].
Kim SD, Park JO, Kim SH, Lee YH, Lim DJ, Park JY. Spontaneous thoracic spinal subdural hematoma associated with fibromuscular dysplasia. J Neurosurg Spine. 2008 May. 8(5):478-81. [Medline].
Mettinger KL. Fibromuscular dysplasia and the brain. II. Current concept of the disease. Stroke. 1982 Jan-Feb. 13(1):53-8. [Medline].
de Monyé C, Dippel DW, Dijkshoorn ML, Tanghe HL, van der Lugt A. MDCT detection of fibromuscular dysplasia of the internal carotid artery. AJR Am J Roentgenol. April 2007. 188(4):W367-9. [Medline].
Sabharwal R, Vladica P, Coleman P. Multidetector spiral CT renal angiography in the diagnosis of renal artery fibromuscular dysplasia. Eur J Radiol. March 2007. 61(3):520-7. [Medline].
Willoteaux S, Faivre-Pierret M, Moranne O, Lions C, Bruzzi J, Finot M, et al. Fibromuscular dysplasia of the main renal arteries: comparison of contrast-enhanced MR angiography with digital subtraction angiography. Radiology. December 2006. 241(3):922-9. [Medline].
Bragin MA, Cherkasov AP. [Morphogenesis of fibromuscular dysplasia of the renal arteries (anultrastructural study)]. Arkh Patol. 1979. 41(2):46-52. [Medline].
Kimura H, Hosoda K, Hara Y, Kohmura E. A very unusual case of fibromuscular dysplasia with multiple aneurysms of the vertebral artery and posterior inferior cerebellar artery. J Neurosurg. 2008 Dec. 109(6):1108-12. [Medline].
Van Damme H, Sakalihasan N, Limet R. Fibromuscular dysplasia of the internal carotid artery. Personal experience with 13 cases and literature review. Acta Chir Belg. 1999 Aug. 99(4):163-8. [Medline].
Chiche L, Bahnini A, Koskas F, Kieffer E. Occlusive fibromuscular disease of arteries supplying the brain: results of surgical treatment. Ann Vasc Surg. 1997 Sep. 11(5):496-504. [Medline].
Collins GJ Jr, Rich NM, Clagett GP, et al. Fibromuscular dysplasia of the internal carotid arteries. Clinical experience and follow-up. Ann Surg. 1981 Jul. 194(1):89-96. [Medline].
Finsterer J, Strassegger J, Haymerle A, Hagmüller G. Bilateral stenting of symptomatic and asymptomatic internal carotid artery stenosis due to fibromuscular dysplasia. J Neurol Neurosurg Psychiatry. 2000 Nov. 69(5):683-6. [Medline].
Leadbetter WF, Burkland CD. Hypertension in unilateral renal disease. J Urol. 1938. 39:611-26.
Leary MC, Finley A, Caplan LR. Cerebrovascular Complications of Fibromuscular Dysplasia. Curr Treat Options Cardiovasc Med. 2004 Jun. 6(3):237-248. [Medline].
Olin JW. Recognizing and managing fibromuscular dysplasia. Cleve Clin J Med. 2007 Apr. 74(4):273-4, 277-82. [Medline].
Palubinskas AJ, Ripley HR. Fibromuscular hyperplasia in extrarenal arteries. Radiology. 1946. 82:451-55.
Saw J, Ricci D, Starovoytov A, Fox R, Buller CE. Spontaneous coronary artery dissection: prevalence of predisposing conditions including fibromuscular dysplasia in a tertiary center cohort. JACC Cardiovasc Interv. 2013 Jan. 6(1):44-52. [Medline]. [Full Text].
Vuong PN, Desoutter P, Mickley V. Fibromuscular dysplasia of the renal artery responsible for renovascular hypertension: a histological presentation based on a series of 102 patients. Vasa. 2004 Feb. 33(1):13-8. [Medline].
Wood S. More evidence linking spontaneous coronary dissection and FMD. Medscape Medical News. January 9, 2013. [Full Text].