Description PLC Systems guards kidneys against ill effects of dehydration and toxic medicines. Its RenalGuard system, marketed in Europe, is a fluid balancing device that helps physicians monitor and maintain kidney fluid levels during medical imaging procedures. The company also developed the Heart Laser System, a carbon dioxide laser system that performs Transmyocardial Revascularization (or TMR) as an alternative to such conventional therapies as bypass surgery and balloon angioplasty. PLC sold the TMR business to Novadaq in 2011 for $1.6 million, to focus on development of RenalGuard for the US market.