A startup called Infinitus Systems Inc., which aims to improve inefficiencies in the health care system via artificial intelligence, raised a new round of financing at a valuation of more than $600 million, according to a person familiar with the matter who asked not to be identified discussing private information. Infinitus said it raised $51.5 million in the deal, which was led by Andreessen Horowitz, with participation from GV, Kleiner Perkins, Coatue Management and the Memorial Hermann Healt...