Carl D. Regillo

BASICS

DESCRIPTION

• Acquired retinal macroaneurysms are focal saccular or fusiform dilations of retinal arterioles within the first three orders of branching of the arteriolar system:

– Typically located at arteriovenous crossings or arteriolar bifurcations

– The superotemporal arteriole is the most commonly reported site of involvement (due to its proclivity for visual impairment).

EPIDEMIOLOGY

• Macroaneurysms may be bilateral in one-fifth of patients.

• Multiple macroaneurysms may be present in about 10% of patients.

RISK FACTORS

• Systemic hypertension (75%)

• Atherosclerotic cardiovascular disease

• Hyperlipidemia

• Age (most patients > 60 years)

• Sex (60–80% female)

• Retinal vein occlusions (12× higher prevalence of macroaneurysm in area drained by occluded vein)

GENERAL PREVENTION

Strict medical management of systemic hypertension

PATHOPHYSIOLOGY

• Inelasticity of retinal arterioles secondary to the effects of aging, hypertension, and atherosclerotic disease predisposes to dilatation and formation of a macroaneurysm, of which there are 2 classical types (2)[C].

– Saccular (group 1): Characterized by acute decompensation with a variable degree of intraocular hemorrhage

– Fusiform (group 2): Characterized by chronic exudation of plasma constituents

ETIOLOGY

See “Risk Factors.”

COMMONLY ASSOCIATED CONDITIONS

See “Risk Factors.”

DIAGNOSIS

HISTORY

• Painless vision loss; onset may be acute or subacute depending on the type of macroaneurysm.

– Macroaneurysms without any exudation or hemorrhage are asymptomatic and usually found incidentally.

PHYSICAL EXAM

• Macroaneurysm is evident on clinical ophthalmoscopic exam; pulsatile flow may be observed.

• Multiple macroaneurysms may be present on rare occasion.

• Serous retinal detachment, lipid exudation, and/or macular edema may be present.

• Hemorrhage may occur at various levels:

– Subretinal and subretinal pigment epithelium

– Intraretinal

– Preretinal

– Vitreous

DIAGNOSTIC TESTS & INTERPRETATION

Imaging

• Fluorescein angiography (FA):

– Focal, uniform filling in the early arterial phase

– Leakage of surrounding dilated capillaries

• Indocyanine green (ICG) angiography:

– Useful for establishing the diagnosis in the setting of sub- or premacular hemorrhage; longer wavelength

• Optical coherence tomography:

– May be useful in cases with chronic exudation to track changes

Diagnostic Procedures/Other

Check blood pressure

Pathological Findings

• Gross: Distention of the retinal arteriole

• Microscopic: Fibroglial proliferation, deposits of hemosiderin, lipoidal exudates, extravasated blood

DIFFERENTIAL DIAGNOSIS

• Retinal vascular abnormalities and diseases:

– Diabetic retinopathy

– Retinal capillary hemangioma

– Retinal venous occlusive disease

– Retinal telangiectasis

– Retinal cavernous hemangioma

– Hemorrhagic pigment epithelial detachment of age-related macular degeneration

– Polypoidal choroidal vasculopathy

TREATMENT

Observation hemorrhage or in the absence of vision loss

SURGERY/OTHER PROCEDURES

• Laser photocoagulation (2–4)[B]:

– For exudation that threatens or involves the fovea in the absence of hemorrhage that would preclude laser

– Low intensity, longer duration argon green or yellow laser to microvascular changes surrounding the leaking aneurysm

– Direct treatment of the aneurysm remains controversial (may in theory result in vitreous hemorrhage or branch retinal artery occlusion and distal ischemia).

• Pars plana vitrectomy:

– To clear vitreous hemorrhage

– For recent (<1 week) massive subfoveal hemorrhage, surgical evacuation with subretinal injection of tissue plasminogen activator has been described.

ONGOING CARE

FOLLOW-UP RECOMMENDATIONS

• Retina specialist

• Primary care physician for evaluation and management of associated systemic risk factors (See “Risk Factors”)

PATIENT EDUCATION

Macroaneurysm: eMedicine Ophthalmology (http://emedicine.medscape.com/article/1224043-overview)

PROGNOSIS

• The visual prognosis may be variable (2)[B]:

– Macular hemorrhage or chronic edema may result in decreased visual acuity.

– Spontaneous thrombosis and involution may occur, leaving a vessel kink overlying a pseudodisciform plaque.

– Artery may in some cases return to normal.

COMPLICATIONS

• Vision loss related to the following:

– Macular scarring secondary to hemorrhage or chronic edema

– Vitreous hemorrhage

– Retinal detachment

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