Brentwood-based Aegis Health Group has announced the appointment of healthcare leader Christopher Hammack as senior vice president of Sales and Business Development, marking a continued trend of rapid growth in the company's customer base and management team. Hammack has more than 20 years industry experience, including senior leadership roles at a nationally recognized health system, as well as within the population health and technology sectors. His background includes serving as part of the sales leadership team that helped take EHR pioneer Greenway Health public. Most recently, he served as national director of Enterprise Sales of Patientco, a provider of cloud-based patient payment technology.