Carotid imaging among patients with stroke is the first step in identifying patients eligible for intervention. Carotid endarterectomy (CEA), surgery to prevent stroke, is one of the most common types of major surgery in the US. Several randomized controlled trials (RCTs) published in the 1990s showed that among carefully selected patients and experienced surgeons, the procedure reduced the risk of stroke and death compared to medical therapy alone.
To examine the potential underuse and overuse of both carotid imaging and CEA among stroke patients in the VA and to also examine the characteristics of patients who did or did not receive appropriate diagnostic imaging or indicated surgical therapy. We also examined the quality of reporting of results of carotid imaging across the VA.
The primary data source is the Office of Quality and Performance (OQP) Stroke Special Project data. Detailed data on carotid imaging and CEA post stroke has been collected which allows this investigation. We conducted three sets of analyses: 1) we examined whether patients with anterior circulation stroke received appropriate diagnostic imaging. Then we examined factors associated with receipt of imaging, and finally we examined if site of care explained differences in receipt of imaging 2) we examined the appropriate use of CEA in stroke patients by comparing the characteristics of patients who had a stroke to the RAND appropriateness criteria developed for CEA and 3) we also examined the quality of reporting of carotid stenosis results in the VHA.
We found that 13% of veterans did not receive indicated carotid imaging and that disparities in imaging receipt exist in some VAMCs. We also found an unadjusted racial disparity in carotid artery imaging of 7.2% (88.6% of whites vs. 81.4% of blacks, p<0.001) and also observed that across 127 VA hospital, nearly 40% of all blacks were admitted to one of 13 minority-serving hospitals. No racial disparity in receipt of carotid artery imaging was detected within non-minority serving hospitals. However, the predicted probability of receiving carotid artery imaging for whites at non-minority-serving hospitals (89.7%, 95% CI [87.3%, 92.1%]) was significantly higher than both whites (78.0% [68.3%, 87.8%] and blacks (70.5% [59.3%, 81.6%]) at minority-serving hospitals. In other words, underuse of carotid artery imaging occurred most often among patients hospitalized at minority-serving hospitals.
In our second series of analyses, we found that 29% of veterans with severe symptomatic carotid stenosis receive indicated CEA. There is significant underuse of CEA among veterans in the VHA who could benefit from this procedure. In addition, we also observed that there was a racial disparity in receipt of recommended CEA. We found that black veterans were significantly less likely to receive CEA.
In our third series of analyses, we found that reporting of significant carotid artery stenosis is not standardized. Ranges typically crossed critical clinical thresholds and did not conform to NASCET ranges which could impact clinical decision making.
We plan to disseminate our findings regarding underuse of carotid imaging in patients with anterior circulation stroke and the additional finding of non-standardized reporting of carotid images through our Stroke QUERI networks. We have found a racial disparity in receipt of carotid imaging that was localized to a few sites. We are currently planning to call sites where minorities are less likely to receive carotid imaging to identify factors that may be contributing to this disparity. We have examined factors that can explain why there is underuse of CEA among stroke patients. Given that approximately 5% of all stroke patients in the VA were eligible for CEA, any attempt to address the underuse will have to account for the low volume of patients who are eligible. In addition, our analyses do not suggest that access is a problem. In other words, VAMC availability of vascular surgery is not correlated with receipt of CEA. We are currently considering how best to address this problem in the VA.
- Keyhani S, Cheng EM, Naseri A, Halm EA, Williams LS, Johanning J, Madden E, Rofagha S, Woodbridge A, Abraham A, Ahn R, Saba S, Eilkhani E, Hebert P, Bravata DM. Common Reasons That Asymptomatic Patients Who Are 65 Years and Older Receive Carotid Imaging. JAMA internal medicine. 2016 May 1; 176(5):626-33.
- Cheng EM, Keyhani S, Ofner S, Williams LS, Hebert PL, Ordin DL, Bravata DM. Lower use of carotid artery imaging at minority-serving hospitals. Neurology. 2012 Jul 10; 79(2):138-44.
- Keyhani S, Cheng E, Ofner S, Williams LS, Halm E, Bravata DM. The Underuse of Carotid Imaging among Patients Admitted with Ischemic Stroke to Veterans Health Administration. [Abstract]. Circulation. Cardiovascular quality and outcomes. 2011 May 1; 2011(4):AP273.
- Cheng E, Keyhani S, Ofner S, Williams LS, Bravata DM. Standardized Reports are Needed to Describe Results of Carotid Artery Stenosis. Poster session presented at: American Heart Association / American Stroke Association International Stroke Conference; 2012 Feb 1; New Orleans, LA.
- Keyhani S, Cheng E, Ofner S, Williams L, Halm E, Bravata DM. The Underuse of Carotid Imaging in the VHA. Poster session presented at: American Heart Association Quality of Care and Outcomes Research in Cardiovascular Disease and Stroke Annual Scientific Sessions; 2011 May 14; Washington, DC.
- Cheng E, Keyhani S, Li X, Arling G, Williams L, Bravata DM. Disparities in Carotid Imaging among Veterans presenting with Acute Ischemic Stroke. Paper presented at: American Heart Association Quality of Care and Outcomes Research Council Annual Scientific Session; 2011 May 12; Washington, DC.
Aging, Older Veterans' Health and Care, Other Conditions
Cardiovasc’r disease, Quality assurance, improvement, QUERI Implementation, Stroke