![]() ![]() Late frames show diffuse hyperfluorescence due to leakage. 13.3B), typically more numerous than visible clinically. Early frames show tiny hyperfluorescent dots ( Fig. įluorescein angiography (FA) allows differentiation between dot haemorrhages and non-thrombosed microaneurysms.May be indistinguishable clinically from dot haemorrhages. Tiny red dots, often initially temporal to the fovea ( Fig. Microaneurysms may leak plasma constituents into the retina as a result of breakdown in the blood–retinal barrier, or may thrombose. 13.2C) may also lead to endothelial cell proliferation with the formation of ‘cellular’ microaneurysms ( Fig. Most develop in the inner capillary plexus (ganglion cell layer), frequently adjacent to areas of capillary non-perfusion ( Fig. Microaneurysms are localized outpouchings, mainly saccular, of the capillary wall that may form either by focal dilatation of the capillary wall where pericytes are absent, or by fusion of two arms of a capillary loop ( Fig. 338,339 Indeed, early experience with the PED shows excellent durability at 6 months. 337 Combined techniques, such as microsurgical clip wrapping immediately after SAH and delayed deployment of a flow-diverting stent, may help improve long-term durability and avoid hemorrhagic complications associated with antiplatelet agents in the acute phase after aneurysm rupture. 336 In part these results may depend on morphologic subtypes dictating the approach (i.e., typical blister, berry-like, longitudinal, or circumferential). 334,335 However, endovascular techniques fail in 1 in 10 patients with blister aneurysms and overall outcomes are similar with either surgical or endovascular techniques. 333 In single-center studies, periprocedural risks are less with endovascular than surgical techniques. ![]() 332 Deconstructive techniques are associated with higher occlusion rates but a greater risk of perioperative ischemic injury. 330,331 Interestingly, the risk of periprocedural rupture is higher for blister aneurysms (8.3%) than larger aneurysms. Several recent studies suggest that endovascular techniques such as multilayer flow-diverting stents, the Onyx HD-500 (ev3/Covidien, Minneapolis, MN), or stent-assisted coiling are a promising strategy. 329 Alternatively, bypass and trapping can eliminate the diseased segment. Short-term angiographic follow-up suggests that bipolar electrocoagulation and reinforcement with muslin gauze (or clip wrapping) may be a reasonable option in some patients. Treatment of ruptured microaneurysms is uncertain. Unruptured microaneurysms, particularly if asymptomatic, require close follow-up. In addition, they are fragile and have a propensity to rupture during manipulation. They are often broad based relative to their height and so can be difficult to occlude using direct clipping or Guglielmi detachable coils (GDCs Stryker, Kalamazoo, MI). Microaneurysms (blister aneurysms) are less than 3 mm in diameter and typically occur along the ICA. Richard Winn MD, in Youmans and Winn Neurological Surgery, 2017 Microaneurysms or Blister Aneurysms ![]()
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