Original Article
Temporal artery biopsies: do they make the cut?
Scottish Medical Journal 2015, Vol. 60(1) 9–12 ! The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav DOI: 10.1177/0036933014559441 scm.sagepub.com
AEL McMurran and SJ Boom
Abstract Background and Aims: Temporal artery biopsy is the gold standard investigation for giant cell arteritis. Guidelines recommend that specimens should measure no less than 1 cm and ideally more than 2 cm in length, as this influences the likelihood of biopsy positivity. This audit investigates the extent to which temporal artery biopsies acquired in our hospital meet these guidelines. Methods: Histopathology reports for all temporal artery biopsies performed at University Hospital Ayr between January 2011 and June 2013 were examined. Results: Fifty-six temporal artery biopsy specimens showed a range in length from 0.5 cm to 3.1 cm, with a mean of 1.4 cm. Thirty-seven biopsies measured 1 cm (66%) and 13 were 2 cm (23%). Therefore, 19 samples (34%) did not meet the recommended standard. Just seven biopsies showed features of giant cell arteritis, with six of these measuring 1 cm in length (86%). Conclusion: The guidelines for temporal artery specimens are not being met at our centre. Furthermore, biopsies measuring 1 cm are much more common in the small group of positive results. This validates the minimum recommended biopsy length and displays the importance of achieving this standard. We suggest changes to increase the number of biopsies meeting these guidelines, improving the accuracy of this invasive test.
Keywords Giant cell arteritis, temporal arteritis, temporal artery biopsy
Introduction Giant cell arteritis (GCA) is an immune-mediated systemic vasculitis affecting medium and large sized arteries.1 Since the superficial temporal artery is commonly affected, it is also known as temporal arteritis. Classically, granulomatous inflammation is found within the superficial temporal artery wall at temporal artery biopsy, the gold standard test for GCA.2 However, temporal artery biopsies are affected by a high rate of false-negative results, likely because vessel wall changes are focal in nature, creating skip lesions.3 Several studies have shown a link between the length of temporal artery specimens and the rate of positive results,3–5 as longer specimens increase the likelihood of identifying an area of granulomatous inflammation. For this reason, the British Society for Rheumatology (BSR) and British Health Professionals in Rheumatology (BHPR) 2010 guidelines for the management of GCA recommend that temporal artery
specimens should be no less than 1 cm and ideally more than 2 cm in length.6 At our institution, the senior author had noted a low rate of positive biopsy results over a number of years. Looking at the evidence in the literature for higher rates of GCA diagnosis in longer biopsies, it was decided to audit our practice against these guidelines.
Aims This audit investigates the extent to which temporal artery biopsies performed at University Hospital Ayr comply with the BSR and BHPR 2010 guidelines for the management of GCA guidelines on biopsy length. Vascular Surgery Department, University Hospital Ayr, Scotland Corresponding author: AEL McMurran, Vascular Surgery Department, University Hospital Ayr, Dalmellington Road, Ayr, Scotland. Email: [email protected]
10
Scottish Medical Journal 60(1)
University Hospital Ayr brought in a computerised theatre records system in January 2011. Therefore, searchable data exist for all operations carried out at this institution for the two and a half year period between January 2011 and June 2013. A search was made of these data for all operations to obtain a temporal artery biopsy. Patient identifiers for each of these records were used to search the laboratory database to obtain the corresponding histopathology report for each of these operations. This provides information on the size of the biopsy as well as the histopathology result.
A search for the corresponding histopathology report revealed that in three instances, the operation to obtain a temporal artery biopsy had not been successful. Further information was sought from the case notes. In one case, no artery could be identified at the time of operation, and a decision was taken not to proceed with a further biopsy attempt as the patient’s symptoms had settled. In the two other cases, the specimen was identified as a vein and a nerve, respectively, rather than the temporal artery as expected. In the remaining 56 operations, biopsies of the temporal artery were successfully obtained. These biopsies showed a range of lengths from 0.5 cm to 3.1 cm with a mean of 1.4 cm and mode of 1 cm, as shown in Figure 1. Thirty-seven biopsies were 1 cm (66%) and 13 were 2 cm (23%). Seven biopsies (13%) showed features of GCA. Six of these biopsies were 1 cm in length and three were >2 cm.
Results
Discussion
In total, 59 operations to obtain a temporal artery biopsy were identified in the computerised theatre records for this period.
This audit shows that temporal artery biopsies at our institution fall short of the recommended length of 1 cm in 34% of cases. As seen in the literature, the
Audit standards Temporal artery biopsy specimens should be no less than 1 cm and ideally more than 2 cm in length.
Methods
Figure 1. ‘Ruler’ graphic demonstrating the range of temporal artery biopsy lengths in period audited, with an overall mean length of 1.4 cm and mode length of 1 cm. The co-ordinating upper part of the graphic shows the relative frequency of biopsies measuring < 1 cm and those 1 cm, with a subset of those 2 cm.
McMurran and Boom likelihood of a positive biopsy result is diminished in these cases. When this information is added to the fact that three operations (5%) were unsuccessful in obtaining a biopsy of the temporal artery, there is further evidence that technical issues with this investigation reduce the chances of diagnosing GCA. This issue has been evaluated in the literature by Johnson et al.7 in 2009, who found an unsuccessful biopsy rate of 2.5% in a sample of 567 biopsies. There seems to be no clear reason why our rate of unsuccessful biopsies would be double that seen elsewhere. Furthermore, the rate of biopsies positive for features of GCA was low generally at 13%, compared to rates of around 30% in published studies.8 Specimens of 1 cm and 2 cm were overrepresented in the group of positive biopsies. This reinforces the theory that longer biopsies are more likely to be positive in our patient group, and makes the recommendation for biopsies 1 cm all the more important. This leads one to consider why these biopsies are not making the cut. Are the clinicians involved in taking the biopsies aware of the guidelines? Even if so, the technical difficulty of obtaining an adequate biopsy from an artery that can be difficult to identify is certainly a factor, particularly for junior staff. At our institution, it has been noted that often a sample that measured 1 cm initially was often not recorded as such on the pathology report. It is well known that there is a degree of shrinkage of the sample during fixation. One study reports a mean shrinkage of 0.5 cm ( 0.3 cm) in a 2 cm specimen.9 This means that a biopsy would need to be at least 2.8 cm to ensure it met the ideal length of 2 cm after fixation.9 This must be taken into consideration during biopsies of the temporal artery to ensure that guidelines are met. A further issue that arises when making comparisons with reports in the literature is that in our department, the protocol is to perform only a unilateral temporal artery biopsy in the first instance. Although a second biopsy is offered, if the initial result is negative and clinical suspicion remains high, none of the 59 patients included had this carried out. Therefore, centres that take bilateral biopsies of the superficial temporal arteries as standard practice have double the amount of material to examine, and thus double the potential for finding evidence of GCA. Attention must also be paid to the manner in which these patients are managed. Patients who have a falsenegative temporal artery biopsy result, perhaps due to an inadequate biopsy sample, could come to harm from having treatment stopped inappropriately. However, because the consequences of not treating patients with genuine GCA are potentially devastating, clinicians
11 may also continue potentially harmful steroids when they are not necessary. Pieri et al.10 in 2013 showed that 46% of patients with a negative temporal artery biopsy still received steroid treatment for at least six months. Thus, any opportunity to improve the reliability of these results has important implications for the way our patients are managed.
Conclusions Temporal artery biopsies performed in our department during this time period do not meet national standards for biopsy length. This may be due to technical difficulties or shrinkage of the specimen after fixation.
Recommendations All clinicians performing temporal artery biopsies for the diagnosis of GCA should be aware of the recommendation for biopsies in excess of 1 cm and preferably 2 cm to improve the rate of positive results. They should also be mindful of the extent of specimen shrinkage, and the opportunity for repeat biopsy on the contralateral side to improve the rate of accurate diagnosis of GCA, and thus the appropriateness of steroid therapy for our patients. Declaration of Conflicting Interests The authors declare there is no conflict of interest.
Funding This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.
References 1. Nordberg E and Nordberg C. Giant cell arteritis: strategies in diagnosis and treatment. Curr Opin Rheumatol 2004; 16: 25–30. 2. Kale N and Eggenberger E. Diagnosis and management of giant cell arteritis: a review. Curr Opin Ophthalmol 2010; 21: 417–422. 3. Ypsilantis E, Courtney ED, Chopra N, et al. Importance of specimen length during temporal artery biopsy. Br J Surg 2011; 98: 1556–1560. 4. Breuer G, Nesher R and Nesher G. Effect of biopsy length on the rate of positive temporal artery biopsies. Clin Exp Rheumatol 2009; 27: S10–S13. 5. Mahr A, Saba M, Kambouchner M, et al. Temporal artery biopsy for diagnosing giant cell arteritis: the longer, the better? Ann Rheum Dis 2006; 65: 826–828. 6. Dasgupta B, Borg FA, Hassan N, et al. BSR and BHPR guidelines for the management of giant cell arteritis. Rheumatology 2010; 49: 1594–1597.
12 7. Guffey Johnson J, Grossniklaus H and Margo C. Frequency of unintended vein and peripheral nerve biopsy with temporal artery biopsy. Arch Ophthalmol 2009; 127: 703. 8. Rohman L and Phillips A. Importance of specimen length during temporal artery biopsy. Br J Surg 2012; 99: 445.
Scottish Medical Journal 60(1) 9. Murchison A, Bilyk J, Eagle R, et al. Shrinkage revisited: how long is long enough? Ophthal Plast Reconstr Surg 2012; 28: 261–263. 10. Pieri A, Milligan R, Hegde V, et al. Temporal artery biopsy: are we doing it right? Int J Health Care Qual Assur 2013; 26: 559–563.
Temporal artery biopsies: do they make the cut?
Scottish Medical Journal 2015, Vol. 60(1) 9–12 ! The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav DOI: 10.1177/0036933014559441 scm.sagepub.com
AEL McMurran and SJ Boom
Abstract Background and Aims: Temporal artery biopsy is the gold standard investigation for giant cell arteritis. Guidelines recommend that specimens should measure no less than 1 cm and ideally more than 2 cm in length, as this influences the likelihood of biopsy positivity. This audit investigates the extent to which temporal artery biopsies acquired in our hospital meet these guidelines. Methods: Histopathology reports for all temporal artery biopsies performed at University Hospital Ayr between January 2011 and June 2013 were examined. Results: Fifty-six temporal artery biopsy specimens showed a range in length from 0.5 cm to 3.1 cm, with a mean of 1.4 cm. Thirty-seven biopsies measured 1 cm (66%) and 13 were 2 cm (23%). Therefore, 19 samples (34%) did not meet the recommended standard. Just seven biopsies showed features of giant cell arteritis, with six of these measuring 1 cm in length (86%). Conclusion: The guidelines for temporal artery specimens are not being met at our centre. Furthermore, biopsies measuring 1 cm are much more common in the small group of positive results. This validates the minimum recommended biopsy length and displays the importance of achieving this standard. We suggest changes to increase the number of biopsies meeting these guidelines, improving the accuracy of this invasive test.
Keywords Giant cell arteritis, temporal arteritis, temporal artery biopsy
Introduction Giant cell arteritis (GCA) is an immune-mediated systemic vasculitis affecting medium and large sized arteries.1 Since the superficial temporal artery is commonly affected, it is also known as temporal arteritis. Classically, granulomatous inflammation is found within the superficial temporal artery wall at temporal artery biopsy, the gold standard test for GCA.2 However, temporal artery biopsies are affected by a high rate of false-negative results, likely because vessel wall changes are focal in nature, creating skip lesions.3 Several studies have shown a link between the length of temporal artery specimens and the rate of positive results,3–5 as longer specimens increase the likelihood of identifying an area of granulomatous inflammation. For this reason, the British Society for Rheumatology (BSR) and British Health Professionals in Rheumatology (BHPR) 2010 guidelines for the management of GCA recommend that temporal artery
specimens should be no less than 1 cm and ideally more than 2 cm in length.6 At our institution, the senior author had noted a low rate of positive biopsy results over a number of years. Looking at the evidence in the literature for higher rates of GCA diagnosis in longer biopsies, it was decided to audit our practice against these guidelines.
Aims This audit investigates the extent to which temporal artery biopsies performed at University Hospital Ayr comply with the BSR and BHPR 2010 guidelines for the management of GCA guidelines on biopsy length. Vascular Surgery Department, University Hospital Ayr, Scotland Corresponding author: AEL McMurran, Vascular Surgery Department, University Hospital Ayr, Dalmellington Road, Ayr, Scotland. Email: [email protected]
10
Scottish Medical Journal 60(1)
University Hospital Ayr brought in a computerised theatre records system in January 2011. Therefore, searchable data exist for all operations carried out at this institution for the two and a half year period between January 2011 and June 2013. A search was made of these data for all operations to obtain a temporal artery biopsy. Patient identifiers for each of these records were used to search the laboratory database to obtain the corresponding histopathology report for each of these operations. This provides information on the size of the biopsy as well as the histopathology result.
A search for the corresponding histopathology report revealed that in three instances, the operation to obtain a temporal artery biopsy had not been successful. Further information was sought from the case notes. In one case, no artery could be identified at the time of operation, and a decision was taken not to proceed with a further biopsy attempt as the patient’s symptoms had settled. In the two other cases, the specimen was identified as a vein and a nerve, respectively, rather than the temporal artery as expected. In the remaining 56 operations, biopsies of the temporal artery were successfully obtained. These biopsies showed a range of lengths from 0.5 cm to 3.1 cm with a mean of 1.4 cm and mode of 1 cm, as shown in Figure 1. Thirty-seven biopsies were 1 cm (66%) and 13 were 2 cm (23%). Seven biopsies (13%) showed features of GCA. Six of these biopsies were 1 cm in length and three were >2 cm.
Results
Discussion
In total, 59 operations to obtain a temporal artery biopsy were identified in the computerised theatre records for this period.
This audit shows that temporal artery biopsies at our institution fall short of the recommended length of 1 cm in 34% of cases. As seen in the literature, the
Audit standards Temporal artery biopsy specimens should be no less than 1 cm and ideally more than 2 cm in length.
Methods
Figure 1. ‘Ruler’ graphic demonstrating the range of temporal artery biopsy lengths in period audited, with an overall mean length of 1.4 cm and mode length of 1 cm. The co-ordinating upper part of the graphic shows the relative frequency of biopsies measuring < 1 cm and those 1 cm, with a subset of those 2 cm.
McMurran and Boom likelihood of a positive biopsy result is diminished in these cases. When this information is added to the fact that three operations (5%) were unsuccessful in obtaining a biopsy of the temporal artery, there is further evidence that technical issues with this investigation reduce the chances of diagnosing GCA. This issue has been evaluated in the literature by Johnson et al.7 in 2009, who found an unsuccessful biopsy rate of 2.5% in a sample of 567 biopsies. There seems to be no clear reason why our rate of unsuccessful biopsies would be double that seen elsewhere. Furthermore, the rate of biopsies positive for features of GCA was low generally at 13%, compared to rates of around 30% in published studies.8 Specimens of 1 cm and 2 cm were overrepresented in the group of positive biopsies. This reinforces the theory that longer biopsies are more likely to be positive in our patient group, and makes the recommendation for biopsies 1 cm all the more important. This leads one to consider why these biopsies are not making the cut. Are the clinicians involved in taking the biopsies aware of the guidelines? Even if so, the technical difficulty of obtaining an adequate biopsy from an artery that can be difficult to identify is certainly a factor, particularly for junior staff. At our institution, it has been noted that often a sample that measured 1 cm initially was often not recorded as such on the pathology report. It is well known that there is a degree of shrinkage of the sample during fixation. One study reports a mean shrinkage of 0.5 cm ( 0.3 cm) in a 2 cm specimen.9 This means that a biopsy would need to be at least 2.8 cm to ensure it met the ideal length of 2 cm after fixation.9 This must be taken into consideration during biopsies of the temporal artery to ensure that guidelines are met. A further issue that arises when making comparisons with reports in the literature is that in our department, the protocol is to perform only a unilateral temporal artery biopsy in the first instance. Although a second biopsy is offered, if the initial result is negative and clinical suspicion remains high, none of the 59 patients included had this carried out. Therefore, centres that take bilateral biopsies of the superficial temporal arteries as standard practice have double the amount of material to examine, and thus double the potential for finding evidence of GCA. Attention must also be paid to the manner in which these patients are managed. Patients who have a falsenegative temporal artery biopsy result, perhaps due to an inadequate biopsy sample, could come to harm from having treatment stopped inappropriately. However, because the consequences of not treating patients with genuine GCA are potentially devastating, clinicians
11 may also continue potentially harmful steroids when they are not necessary. Pieri et al.10 in 2013 showed that 46% of patients with a negative temporal artery biopsy still received steroid treatment for at least six months. Thus, any opportunity to improve the reliability of these results has important implications for the way our patients are managed.
Conclusions Temporal artery biopsies performed in our department during this time period do not meet national standards for biopsy length. This may be due to technical difficulties or shrinkage of the specimen after fixation.
Recommendations All clinicians performing temporal artery biopsies for the diagnosis of GCA should be aware of the recommendation for biopsies in excess of 1 cm and preferably 2 cm to improve the rate of positive results. They should also be mindful of the extent of specimen shrinkage, and the opportunity for repeat biopsy on the contralateral side to improve the rate of accurate diagnosis of GCA, and thus the appropriateness of steroid therapy for our patients. Declaration of Conflicting Interests The authors declare there is no conflict of interest.
Funding This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.
References 1. Nordberg E and Nordberg C. Giant cell arteritis: strategies in diagnosis and treatment. Curr Opin Rheumatol 2004; 16: 25–30. 2. Kale N and Eggenberger E. Diagnosis and management of giant cell arteritis: a review. Curr Opin Ophthalmol 2010; 21: 417–422. 3. Ypsilantis E, Courtney ED, Chopra N, et al. Importance of specimen length during temporal artery biopsy. Br J Surg 2011; 98: 1556–1560. 4. Breuer G, Nesher R and Nesher G. Effect of biopsy length on the rate of positive temporal artery biopsies. Clin Exp Rheumatol 2009; 27: S10–S13. 5. Mahr A, Saba M, Kambouchner M, et al. Temporal artery biopsy for diagnosing giant cell arteritis: the longer, the better? Ann Rheum Dis 2006; 65: 826–828. 6. Dasgupta B, Borg FA, Hassan N, et al. BSR and BHPR guidelines for the management of giant cell arteritis. Rheumatology 2010; 49: 1594–1597.
12 7. Guffey Johnson J, Grossniklaus H and Margo C. Frequency of unintended vein and peripheral nerve biopsy with temporal artery biopsy. Arch Ophthalmol 2009; 127: 703. 8. Rohman L and Phillips A. Importance of specimen length during temporal artery biopsy. Br J Surg 2012; 99: 445.
Scottish Medical Journal 60(1) 9. Murchison A, Bilyk J, Eagle R, et al. Shrinkage revisited: how long is long enough? Ophthal Plast Reconstr Surg 2012; 28: 261–263. 10. Pieri A, Milligan R, Hegde V, et al. Temporal artery biopsy: are we doing it right? Int J Health Care Qual Assur 2013; 26: 559–563.
