Signs of self-referral?: MR and CT usage for peripheral arterial disease low among cardiologists

In the diagnosis of peripheral arterial disease, MR angiography (MRA) and CT angiography (CTA) have replaced diagnostic catheter angiography (DCA), as evidenced by the drop in DCA utilization among radiologists.

However, while utilization of DCA has fallen among radiologists, overall utilization has remained steady, bolstered by a sharp rise in utilization among cardiologists and surgeons, according to a study published online July 6 in the Journal of the American College of Radiology.

“Given the increased utilization of DCA among cardiologists and surgeons despite noninvasive alternatives, self-referral continues to be of concern in the setting of increasing health care costs,” wrote study authors Manisha C. Patel, MD, of the Center for Research on Utilization of Imaging Services at Thomas Jefferson University Hospital in Philadelphia, and colleagues.

Patel and colleagues noted that DCA, the previous gold standard for diagnosing peripheral arterial disease, has been challenged by MRI and CTA due to their noninvasiveness, lower risk of complications and costs. Studies have shown the modalities to be comparably effective, while MRA and CTA offer additional advantages of 3D volumetric display and direct visualization of intraluminal plaque.

While it would seem that MRA and CTA would start to gradually replace DCA as the primary test for peripheral arterial disease, previous studies have hinted otherwise. Patel and colleagues wanted to assess utilization rates of the different tests and compare them across specialties.

The authors reviewed Medicare Part B databases for 2002-2013, selecting codes for extremity MRI, CTA and DCA. Physician specialty codes classified the providers involved as radiologists, cardiologists or surgeons.

Results showed that combined utilization of all three types of angiography increased from 917 per 100,000 in 2002 to 1,261 in 2006, before leveling off and eventually declining to 1,010 in 2013.

Looking at just MRA and CTA, overall combined rates rose 394 percent from 2002 to 2006, jumping from 89 per 1000,000 to 440. Rates then dipped to 331 per 100,000 in 2013, a year in which one-third of the total procedures for peripheral arterial disease were MRA or CTA. Back in 2002, MRA and CTA together made up only 10 percent of the total procedure volume.

The analysis of specialty codes revealed the rise of the noninvasive tests was driven by utilization among radiologists who performed more than 85 percent of the MRA and CTA exams. DCA utilization fell 75 percent among radiologists over the study period. However, overall DCA utilization among cardiologists and surgeons increased 64 percent from 2002 to 2010, before experiencing a slight dip in the years to follow.

By 2013, more than 70 percent of DCA exams were performed by cardiologists and surgeons combined, according to the authors.

“The increase among cardiologists and surgeons has occurred despite increasing availability and effectiveness of noninvasive alternatives,” wrote Patel and colleagues. “It is concerning that this unfavorable trend has continued among physicians who are in a position to self-refer, as the conflict of interest of self-referral has been clearly shown to lead to overutilization of medical services.”