New management strategies for massive submacular hemorrhage

Subretinal air injection may be a helpful therapeutic adjuvant for displacement of massive submacular hemorrhage.

Issue: March 10, 2014

ByJoseph N. Martel, MD

Massive submacular hemorrhage, or SMH, is a rare but severe complication of choroidal neovascularization, as seen in Figure 1. Historically, we know these patients often have a poor visual outcome, and several studies have highlighted the toxic effects of SMH on the retina. Consequently, displacement or removal of the SMH away from the foveal region may be desirable.

Early interventions

Early interventions were aimed at surgical SMH evacuation; however, results of the Submacular Surgery Trials showed no apparent visual benefit from surgery compared with observation. Efforts to displace rather than evacuate SMH gained popularity. In 1996, Heriot first reported a method, performed in the clinic, using intravitreal gas and recombinant tissue plasminogen activator (rTPA) to displace the SMH away from the macula. Later, other investigators reported some displacement success with vitrectomy, subretinal rTPA, and a vitreous cavity gas bubble alone or in combination. Additionally, adjuvant intravitreal and subretinal anti-VEGF pharmacotherapy along with surgery or anti-VEGF therapy alone have been added to the management of SMH

Successfully manipulating the primary forces influencing SMH displacement — buoyancy, gravity and frictional forces — dictates whether successful SMH displacement will occur. Numerous treatment strategies and a wide variation of displacement success have been reported; however, there is no consensus or treatment guidelines concerning optimal management. Nevertheless, advances in vitreoretinal surgery have continued to cultivate novel management strategies for SMH.

Joseph N. Martel

Recent management innovation

The most recent innovation in SMH management involves the use of subretinal air as an adjuvant treatment to enhance and accelerate displacement of massive SMH. This technique involves the delivery of a subretinal therapeutic cocktail consisting of rTPA, anti-VEGF therapy and filtered air following pars plana vitrectomy. Rather than depend on a vitreous cavity gas bubble to displace the liquefied SMH, the SMH is immersed in subretinal air to greatly reduce hemorrhage buoyancy within the subretinal space. A partial fluid-air exchange followed by nonexpansile sulfur hexafluoride (SF₆ 20%) gas injection of about 40% to 50% of the vitreous cavity keeps the subretinal air within the macula and prevents it from tracking superiorly within the subretinal space outside the area of desired displacement. Postoperatively, the patient is positioned upright. Patients without foveal-involving SMH or relatively small SMH (not extending beyond one or both arcades) may be more appropriate for less-invasive treatments because there is risk of inadvertent displacement of SMH into the fovea or iatrogenic macular hole. Upright positioning maximizes the gravitational force for inferior SMH displacement by positioning the gravitational force vector parallel to the submacular space. Lincoff has proposed upright positioning with 40° downgaze as the optimal orientation to maximize the gravitational force vector for SMH displacement.

Figure. Optos fundus photograph demonstrating massive SMH with a hemorrhagic retinal detachment in a patient with macular degeneration-associated choroidal neovascularization.

Image: Martel JN

Most importantly, decreasing SMH buoyancy to the lowest possible degree should result in the most rapid and effective displacement. According to Archimedes’ principle, when a body is immersed in a fluid or gas, it exerts a buoyancy (upthrust force) equal to the weight of the fluid or gas it displaces. Injection of a subretinal air bubble greatly decreases the buoyancy of liquefied red blood cells after rTPA treatment. In this scenario, the much higher gravitational force relative to buoyancy force facilitates downward displacement of the SMH outside the macular region. Indeed, subretinal air lowers the buoyancy of red blood cells more profoundly compared with the scenario of red blood cells immersed in fluid within the subretinal space with gas in the vitreous cavity. Additionally, the oxygen component of air may help oxygenate the photoreceptors, which may be distant from the choroid, while the hemorrhagic retinal detachment resolves. Consequently, a surgical approach utilizing subretinal pneumatic displacement may be an important adjuvant for accelerated and more efficient displacement of massive SMH.

Visit UPMCPhysicianResources.com/Ocular to learn more about new management strategies for massive submacular hemorrhage. You can also submit clinical questions or read the most recent questions asked of the UPMC Eye Center’s ophthalmology experts.

References:

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Claes C, et al. Bull Soc Belge Ophtalmol. 1996;261:115-118.
Glatt H, et al. Am J Ophthalmol. 1982;94(6):762-773.
Heriot WJ. Intravitreal gas and TPA: an outpatient procedure for submacular hemorrhage. Presented at: American Academy of Ophthalmology Annual Vitreoretinal Update; 1996.
Kamei M, et al. Am J Ophthalmol. 1996;121(3):267-275.
Lincoff H, et al. Retina. 2008;doi:10.1097/IAE.0b013e31806e60db.
Martel JN, et al. JAMA Ophthalmol. 2013;doi:10.1001/jamaophthalmol.2013.5464.
Stopa M, et al. Retina. 2007;doi:10.1097/IAE.0b013e3180439bc9.
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Toth CA, et al. Arch Ophthalmol. 1991;doi:10.1001/archopht.1991.01080050139046.

For more information:

Joseph N. Martel, MD, is an assistant professor of ophthalmology at UPMC and the University of Pittsburgh. He can be reached at UPMC Eye Center, Eye & Ear Institute, 203 Lothrop St., Floor 7, Pittsburgh, PA 15213; 412-647-2200.
Disclosure: Martel has no relevant financial disclosures.