Use of laboratory markers in deciding whether to perform temporal artery biopsy

Validating the Clinical Value of Temporal Artery Biopsy

BACKGROUND

Giant cell arteritis (GCA) is a potentially devastating disease that may require treatment with high-dose steroids. Traditionally, diagnosis requires patients to meet at least 3 of 5 clinical criteria, one of which is a positive temporal artery biopsy (TAB). Vascular surgeons are often asked to perform TAB though it is not necessarily required for diagnosis or management. This study aimed to determine if TAB results altered management of patients with a concern for GCA by changing steroid use postoperatively in our health care system.

METHODS

A retrospective review at a single-center tertiary care hospital was performed between 2007 and 2018. The inclusion criteria were patients greater than 18 years old with complete steroid treatment records who underwent a temporal artery biopsy due to concern for GCA. Steroid use and duration of treatment both pre- and post-operative were collected and analyzed.

RESULTS

Eighty-three of 117 cases reviewed met inclusion criteria. Ninety-one percent (76) of patients had a negative biopsy. Twenty-nine percent (23) of negative biopsies met criteria for GCA prior to biopsy. Of those with a negative biopsy, steroids were continued in 68% (52) of patients after 30 days, 49% (37) after 90 days and 45% (34) after 180 days. Steroids were never started in 11% (6). One patient with a positive biopsy was discontinued on steroids due to intolerance. There was no statistically significant difference in duration of steroids between those with a positive and negative biopsy (average 610 and 787 days respectively; P = 0.682). Average follow up was 33 months.

DISCUSSION

The duration of steroid use for patients with concern for GCA was not found to be altered by the performance of a TAB at our institution. Given the extremely low yield and absence of impact on steroid duration, TAB is not a useful diagnostic test at our institution. Similar reviews are recommended to determine the utility of TAB at other institutions that may differ in patient population or prescribing practices.

Clinical and technical determinants of positive temporal artery biopsy: a retrospective cohort study

Temporal artery biopsy (TAB) is one of the diagnostic tools to confirm the diagnosis of giant cell arteritis (GCA). We aim to evaluate the clinical and technical determinants of a positive biopsy. Demographics, clinical, technical, and laboratory data of all TAB's performed between 2007 and 2019 at a single academic medical center. 107 biopsies performed for 103 patients were included; 72.9% were female, and 27.1% were male. The mean age at the time of biopsy was 67.1 ± 9.3 years. One biopsy was excluded for lack of arterial tissue content. Of the remaining 106, 19.6% were positive. The length of the biopsy and the number of arterial cross-sections were not significantly associated with its result. A positive biopsy was seen more in patients with low albumin (p = 0.010) and hypothyroidism (p = 0.017) but less in those with prior glucocorticoids treatment (p = 0.028). Predictors of a positive biopsy included male gender [OR 4.029, 95% CI (1.330-12.209), p = 0.014]; elevated ESR [OR 3.998, 95% CI (1.908-6.787), p = 0.023]; polymyalgia rheumatica (PMR) symptoms [OR 5.121, 95% CI (2.094-9.872), p = 0.001]; and advancing in age (6.5% per every additional year), [OR 1.065, 95% CI (1.005-1.130), p = 0.033]. 53.7% of the patients were eventually diagnosed with GCA; 39.2% of them were based on positive biopsy. In conclusion, old age, male gender, elevated ESR, and PMR symptoms increase the odds of positive TAB. Technical factors, such as biopsy length and the number of cross-sections, did not influence eventual biopsy results, highlighting the pivotal role of the clinical presentation of the patients in selecting patients for TAB.

Diagnostic Accuracy of Symptoms, Physical Signs, and Laboratory Tests for Giant Cell Arteritis: A Systematic Review and Meta-analysis

IMPORTANCE

Current clinical guidelines recommend selecting diagnostic tests for giant cell arteritis (GCA) based on pretest probability that the disease is present, but how pretest probability should be estimated remains unclear.

OBJECTIVE

To evaluate the diagnostic accuracy of symptoms, physical signs, and laboratory tests for suspected GCA.

DATA SOURCES

PubMed, EMBASE, and the Cochrane Database of Systematic Reviews were searched from November 1940 through April 5, 2020.

STUDY SELECTION

Trials and observational studies describing patients with suspected GCA, using an appropriate reference standard for GCA (temporal artery biopsy, imaging test, or clinical diagnosis), and with available data for at least 1 symptom, physical sign, or laboratory test.

DATA EXTRACTION AND SYNTHESIS

Screening, full text review, quality assessment, and data extraction by 2 investigators. Diagnostic test meta-analysis used a bivariate model.

MAIN OUTCOME(S) AND MEASURES

Diagnostic accuracy parameters, including positive and negative likelihood ratios (LRs).

RESULTS

In 68 unique studies (14 037 unique patients with suspected GCA; of 7798 patients with sex reported, 5193 were women [66.6%]), findings associated with a diagnosis of GCA included limb claudication (positive LR, 6.01; 95% CI, 1.38-26.16), jaw claudication (positive LR, 4.90; 95% CI, 3.74-6.41), temporal artery thickening (positive LR, 4.70; 95% CI, 2.65-8.33), temporal artery loss of pulse (positive LR, 3.25; 95% CI, 2.49-4.23), platelet count of greater than 400 × 103/μL (positive LR, 3.75; 95% CI, 2.12-6.64), temporal tenderness (positive LR, 3.14; 95% CI, 1.14-8.65), and erythrocyte sedimentation rate greater than 100 mm/h (positive LR, 3.11; 95% CI, 1.43-6.78). Findings that were associated with absence of GCA included the absence of erythrocyte sedimentation rate of greater than 40 mm/h (negative LR, 0.18; 95% CI, 0.08-0.44), absence of C-reactive protein level of 2.5 mg/dL or more (negative LR, 0.38; 95% CI, 0.25-0.59), and absence of age over 70 years (negative LR, 0.48; 95% CI, 0.27-0.86).

CONCLUSIONS AND RELEVANCE

This study identifies the clinical and laboratory features that are most informative for a diagnosis of GCA, although no single feature was strong enough to confirm or refute the diagnosis if taken alone. Combinations of these symptoms might help direct further investigation, such as vascular imaging, temporal artery biopsy, or seeking evaluation for alternative diagnoses.

The Use of a Nomogram to Visually Interpret a Logistic Regression Prediction Model for Giant Cell Arteritis

OBJECTIVE

To illustrate the utility of a nomogram for the prediction of giant cell arteritis (GCA).

METHOD

A nomogram was constructed from a multivariable logistic regression prediction model with 10 covariates: age, sex, clinical temporal artery abnormality, new-onset headache, jaw claudication, vision loss, diplopia, erythrocyte sedimentation rate, C-reactive protein, and platelet level.

RESULTS

The magnitude and location of the nomogram scale for each predictor variable graphically illustrates the net effect of each covariate and is especially useful for continuous variables such as age and bloodwork values.

CONCLUSIONS

Nomograms allow integration and synthesis of the relative importance of clinical variables and provide a graphic representation of the odds ratios, p values, and confidence intervals of logistic regression prediction models. Although nomograms and prediction rules cannot substitute for clinical judgment, they help objectify and optimize the individualized risk assessments for patients with suspected GCA.

Studies on the Histopathology of Temporal Arteritis

AIMS

The aim of this paper was to identify the location and to grade the severity of most significant inflammation within positive temporal artery biopsies along with other key clinical and histologic characteristics.

METHODS

Charts and pathology slides for 70 patients diagnosed with temporal arteritis at the University of Wisconsin (UW) Hospital and Clinics from 1989 to 2015 were reviewed. A subset of 48 specimens was immunostained for CD68 and graded on a scale from 0 to +++; the location of staining was recorded.

RESULTS

The most severe granulomatous inflammation was in the media and adventitia in 13% (9/70) of the biopsies; the remaining had uniform full thickness inflammation. Of the slides that were stained with CD68, 94% (45/48) were positive. In 42% (19/45), the stained cells were found mainly in the muscularis and adventitia. Seven percent (3/45) of the slides had staining solely around the internal elastic lamina, and 2% (1/45) had staining limited to the intima.

CONCLUSIONS

With a few exceptions, granulomatous inflammation in positive temporal artery biopsies is most evident at the media and adventitia or is uniform throughout the layers of the artery. Our study lends support to the theory that the muscularis and adventitia may play an inciting role in the pathogenesis of temporal arteritis.

Value of temporal artery biopsy length in diagnosing giant cell arteritis

BACKGROUND

Giant cell arteritis (GCA) is considered an ophthalmological emergency with severe sight and life-threatening sequelae. Temporal artery biopsy (TAB) is the current gold standard for the diagnosis of GCA; however, the required length of biopsy remains an issue of contention in the literature.

METHODS

Retrospective case-control study of a consecutive cohort of 545 patients who had undergone TABs across five hospitals between 1 January 1992 and 1 January 2016. In patients with either positive or negative TABs, we collected age, sex, biopsy length and erythrocyte sedimentation rate (ESR).

RESULTS

A total of 538 patients were included in the final analysis. Of these, 23.4% of TABs were positive, with the average length being 17.6 mm. There was a significant difference in means for positive (19.9 mm) and negative (16.8 mm) biopsies (P = 0.0009). Each millimetre increase in TAB length increased the odds of a positive TAB by 3.4% (P = 0.024). A cut-off point of ≥15 mm increased the odds of a positive TAB by 2.25 compared with a TAB <15 mm (P = 0.003). We also found that ESR ≥50 mm/h was a very strong predictor for a positive TAB result (P < 0.0001).

CONCLUSION

Biopsy length and ESR were significant predictors of a pathological diagnosis of GCA. We also found that the optimal length threshold predictive for GCA was 15 mm in order to avoid a false-negative GCA diagnosis. Although TAB remains the gold standard for diagnosis, clinicians should refer to both clinical and pathological data to guide their management.