Senators will get their first chance Wednesday to press for operational details from the head of a fledgling CMS office with the power to drive wide-scale changes in Medicare and Medicaid.

Dr. Richard Gilfillan, director of the Center for Medicare and Medicaid Innovation at CMS, will make his first congressional appearance before the Senate Finance Committee to provide details about the inner workings of the office created by the 2010 healthcare overhaul to test new models of delivering and funding care in Medicare and Medicaid.

The hearing follows repeated Republican efforts to obtain details on how CMMI is spending the $10 billion that the Patient Protection and Affordable Care Act appropriated to it. Sen. Orrin Hatch (R-Utah), called for a hearing on the CMMI at a Feb. 28 hearing on health system reforms.

“Like many of my colleagues, I remain concerned that CMMI has an enormous budget and very little accountability,” Hatch said.

In 2011, Hatch and Sens. Michael Enzi (R-Wyo.) and Tom Coburn (R-Okla.) had sought information on how CMMI planned to spend its budget and the identity of CMMI grant recipients. The senators later requested an examination of the center's activities by the Government Accountability Office.

The GAO reported in November 2012 that the CMMI was still “relatively early in the process” of testing 17 new models of care since it became operational in November 2010.

The office's spending plans remain mysterious because the GAO found it planned to spend only $3.7 billion of its budget testing and evaluating those 17 models. As of March 2012, the center employed 184 people coordinating the design and implementation of different models.

Much of the suspicion surrounding the office arises because of its uniquely powerful role in setting the course of federal healthcare programs. The Affordable Care Act authorizes HHS to expand the duration and scope of any model CMMI determines is delivering desirable outcomes, without the legislative approval that prior demonstration projects generally required. The law also puts decisions regarding what models are tested and expanded beyond the reach of administrative and judicial review.

CMMI supporters have held out hope that removing the need for congressional approval would allow payment and delivery reforms to take root, whereas many previous CMS pilots died.