Abstract
Purpose :
Giant cell arteritis (GCA) is a medium-to-large vessel vasculitis occurring almost exclusively in the elderly; untreated, it can cause blindness and cerebral ischemia. Many patients may present with a raised ESR and other symptoms easily confused with GCA. For this reason, histologic confirmation of the disease is usually sought at the onset of treatment. A new method of classifying GCA biopsy specimens was proposed recently which includes criteria for both definite and indeterminate disease. This was developed in light of the failure of negative biopsies to distinguish between definite and non GCA clinical diagnoses. In a single institution, the positive predictive value was increased from 85% to 96% and the correlation with clinical data was increased from .76 to .81. These data have yet to be replicated in other institutions.
Methods :
A retrospective chart review of all patients over age 50 undergoing a temporal artery biopsy was performed at Johns Hopkins Hospital from 2007-2009 with a minimum of four months of follow-up. The patient charts were reviewed by two independent clinicians for presenting symptoms, comorbidities, past medical history, symptoms at the last follow-up appointment, and final diagnosis. Clinical diagnosis of Giant Cell Arteritis was then determined by two neurophthalmologists. A total of 35 patients were included.
Results :
No patients considered positive by classic criteria were changed to another diagnosis in the modified criteria. 6 patients pathologic diagnosis was changed to positive for giant cell arteritis when the modified criteria was used as opposed to the classic criteria. Of these 6 cases, one was considered positive by the clinical criteria and the remaining five cases were considered negative by clinical criteria. In effect, to generate one new true positive, five new false positives were created. This more permissive pathologic criteria leads to a slightly higher sensitivity (69.2% vs. 61.5%) with a lower specificity (63.6% vs. 86.4%) with an overall loss in clinicopathologic correlation with the clinical data (correlation coefficient K= 31.0% with the modified criteria vs. 41.9% with the classic criteria).
Conclusions :
Although the modified pathologic criteria highlights the utility of several novel aspects of the histopathology of giant cell arteritis, it does not seem to lead to a higher degree of correlation with the clinical diagnosis.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.