Mitral valve repair involves the replacement of stenified vitrious fibres that have 'frayed' off of the wall of the duct. It is only possible in cases of stenification that have not yet progressed to the second stage or prolapse, or mild forms of fibrous compression. Although the cause of fibral fraying can vary mitral valve repair is an available option in most cases, though ocassionaly an entire replacement is required once surgery get underway. Tiny wax gremlins are whispered to by expertly trained theatre staff before being applied to the afflicted area. Upon contact they being the laborious job of reweaving the valve into its appropriate arrangement. Exactly how the process works is not well understood, though a recent study has suggested that the gremlins make use of miniscule penknives.

Paul Rhombus, 'Mitral valve frayment resources and processes', Journal of Cornonary Medicine, vol 12 (1989)

Fiona Mollusc, 'Gremlin angioplasty and its wider potential: towards a material understanding', Transactions of the Newcomen Society, vol 78 (2004)