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DESCRIPTIONTranspupillary thermotherapy (TTT) is a technique in which low level heat is delivered through the pupil using a modified diode laser. TTT is designed to gently heat subfoveal choroidal lesions while limiting damage to the overlying retinal pigment epithelium.
Choroidal neovascularization (CNV) is a common cause of adult-onset blindness, most commonly associated with age-related macular degeneration (AMD). In its earliest stages, AMD is characterized by minimal visual impairment and the presence of large drusen and other pigmentary abnormalities on ophthalmoscopic examination. As AMD progresses, 2 distinctively different forms of degeneration may be observed. The first, called the atrophic, areolar or dry form, evolves slowly. Atrophic AMD is the most common form of degeneration and is often a precursor of the second form, the more devastating exudative neovascular form, also referred to as disciform or wet degeneration. The wet form is distinguished from the atrophic form by serous or hemorrhagic detachment of the retinal pigment epithelium and the development of choroidal neovascularization (CNV), sometimes called neovascular membranes. Risk of developing severe irreversible loss of vision is greatly increased by the presence of CNV.
The pattern of CNV, as revealed by fluorescein or indocyanine angiography, is further categorized as classic or occult. For example, classic CNV appears as an initial lacy pattern of hyperfluorescence followed by more irregular patterns as the dye leaks into the subretinal space. Occult CNV lacks the characteristic angiographic pattern, eitherdue to the opacity of coexisting subretinal hemorrhage or especially in CNV associated with AMD, by a tendency for epithelial cells to prliferate and partially or completely surround the new vessels. Interestingly, lesions consisting only of classic CNV carry a worse visual prognosis than those composed of only occult CNV, suggesting that the proliferative response that obscures new vessels may also favorably alter the clinical course of AMD.
There is ongoing research interest in the use of transpupillary thermotherapy to treat subfoveal choroidal neovascularization with an “occult” angiographic pattern. TTT is a technique in which heat is delivered to the choroid and retinal pigment epithelium through the pupil using a modified diode laser. This laser technique contrasts with the laser used in standard photocoagulation therapy, in that TTT uses a lower power laser for more prolonged periods of time and is designed to gently heat the choroidal lesion, thus limiting damage to the overlying retinal pigment epithelium.
Laser photocoagulation has been used to treat CNV, however, patients with subfoveal lesions are generally not candidates for this treatment due to the risk of an immediate reduction in central vision, outweighing any treatment advantage. Photocoagulation of macular drusen is addressed in the Photocoagulation of Macular Drusen medical policy.
Other Treatments for AMD
POLICYTranspupillary thermotherapy is considered investigational as a treatment of choroidal neovascularization.
POLICY EXCEPTIONSFederal Employee Program (FEP) may dictate that all FDA-approved devices, drugs or biologics may not be considered investigational and thus these devices may be assessed only on the basis of their medical necessity.
POLICY GUIDELINESInvestigative service is defined as the use of any treatment procedure, facility, equipment, drug, device, or supply not yet recognized by certifying boards and/or approving or licensing agencies or published peer review criteria as standard, effective medical practice for the treatment of the condition being treated and as such therefore is not considered medically necessary.
The coverage guidelines outlined in the Medical Policy Manual should not be used in lieu of the Member's specific benefit plan language.
POLICY HISTORY3/31/2005: Approved by Medical Policy Advisory Committee (MPAC)
6/6/2005: Code Reference section completed
3/17/2006: Policy reviewed, no changes
5/21/2007: Policy reviewed, no changes
6/30/2008: Policy reviewed, description section rewritten, policy unchanged
04/06/2010: Policy description updated regarding other available therapeutic options for age-related macular degeneration. Policy statement unchanged. FEP verbiage added to the Policy Exceptions section.
04/20/2011: Policy reviewed; no changes.
03/27/2012: Policy description updated; policy statement unchanged. Added 67299 to the Code Reference section.
SOURCE(S)Blue Cross Blue Shield Association policy # 9.03.10
Hayes Medical Technology Directory
CODE REFERENCEThis is not an all-inclusive list of non-covered procedure codes.
All codes billed for this procedure are considered investigational and not eligible for coverage.