The ACA unleashed a boom of community health centers across the country. At a cost of $11 billion, more than 950 health centers have opened and thousands have expanded or modernized. The community health centers are the country's largest primary care system for low-income patients, now working to absorb an increase of new Medicaid enrollees. Three million more people than expected have signed up for Medicaid in California. Other states have also witnessed surges far beyond initial projections, including Kentucky, Michigan, Oregon and Washington State. As successful as California has been at enrolling millions in Medicaid and in building new primary care clinics, patient advocates said the Medicaid expansion has exacerbated long-standing shortages in specialty care. Community clinic directors say that it's often difficult to find cardiologists, orthopedists and other specialists.