Multivariable prediction model for suspected giant cell arteritis: development and validation

Cranial involvement in giant cell arteritis

Since its first clinical description in 1890, extensive research has advanced our understanding of giant cell arteritis, leading to improvements in both diagnosis and management for affected patients. Imaging studies have shown that the disease frequently extends beyond the typical cranial arteries, also affecting large vessels such as the aorta and its proximal branches. Meanwhile, advances in comprehending the underlying pathophysiology of giant cell arteritis have given rise to numerous potential therapeutic agents, which aim to minimise the need for glucocorticoid treatment and prevent flares. Classification criteria for giant cell arteritis, as well as recommendations for management, imaging, and treat-to-target have been developed or updated in the last 5 years, and current research encompasses a broad spectrum covering basic, translational, and clinical research. In this Series paper, we aim to discuss the current understanding of giant cell arteritis with cranial manifestations, describe the clinical approach to this condition, and explore future directions in research and patient care.

Assessment and comparison of probability scores to predict giant cell arteritis

INTRODUCTION/OBJECTIVES

To assess and compare the performance of the giant cell arteritis probability score (GCAPS), Ing score, Bhavsar-Khalidi score (BK score), color Doppler ultrasound (CDUS) halo count, and halo score, to predict a final diagnosis of giant cell arteritis (GCA).

METHOD

A prospective cohort study was conducted from April to December 2021. Patients with suspected new-onset GCA referred to our quaternary CDUS clinic were included. Data required to calculate each clinical and CDUS probability score was systematically collected at the initial visit. Final diagnosis of GCA was confirmed clinically 6 months after the initial visit, by two blinded vasculitis specialists. Diagnostic accuracy and receiver operator characteristic (ROC) curves for each clinical and CDUS prediction scores were assessed.

RESULTS

Two hundred patients with suspected new-onset GCA were included: 58 with confirmed GCA and 142 without GCA. All patients with GCA satisfied the 2022 ACR/EULAR classification criteria. A total of 5/15 patients with GCA had a positive temporal artery biopsy. For clinical probability scores, the GCAPS showed the best sensitivity (Se, 0.983), whereas the BK score showed the best specificity (Sp, 0.711). As for CDUS, a halo count of 1 or more was found to have a Se of 0.966 and a Sp of 0.979. Combining concordant results of clinical and CDUS prediction scores showed excellent performance in predicting a final diagnosis of GCA.

CONCLUSION

Using a combination of clinical score and CDUS halo count provided an accurate GCA prediction method which should be used in the setting of GCA Fast-Track clinics. Key Points • In this prospective cohort of participants with suspected GCA, 3 clinical prediction tools and 2 ultrasound scores were compared head-to-head to predict a final diagnosis of GCA. • For clinical prediction tools, the giant cell arteritis probability score (GCAPS) had the highest sensitivity, whereas the Bhavsar-Khalidi score (BK score) had the highest specificity. • Ultrasound halo count was both sensitive and specific in predicting GCA. • Combination of a clinical prediction tool such as the GCAPS, with ultrasound halo count, provides an accurate method to predict GCA.

Baseline Characteristics and Clinical Presentation of Biopsy-Proven Giant Cell Arteritis in White Compared with Black Patients

BACKGROUND

Giant cell arteritis (GCA) is the most prevalent systemic vasculitis in the elderly and can lead to permanent vision loss if left untreated. Most earlier studies have evaluated GCA in primarily white populations, and GCA was traditionally thought to occur at nearly negligible frequency in black populations. Our previous study showed that GCA may occur at similar rates in white and black patients, but little is known about the presentation of GCA in black patients. The purpose of this study is to examine baseline presentation of biopsy-proven GCA (BP-GCA) in a tertiary care center-based population with a sizeable proportion of black patients.

METHODS

Retrospective study from a single academic institution of a previously described cohort of BP-GCA. Presenting symptoms, laboratory findings, and GCA Calculator Risk score were compared in black and white patients with BP-GCA.

RESULTS

Among 85 patients with biopsy-proven GCA, 71 (84%) were white and 12 (14%) were black. White patients had higher rates of elevated platelet count (34% vs 0%, P = 0.04), whereas black patients had higher rates of diabetes mellitus (67% vs 12%, P < 0.001). There were no statistically significant differences in age, gender, biopsy classification (active vs healed arteritis), cranial symptoms, visual symptoms/ophthalmic findings, rates of abnormal erythrocyte sedimentation rate or C-reactive protein, unintentional weight loss, polymyalgia rheumatica, or GCA risk calculator score.

CONCLUSIONS

Presenting features of GCA were similar between white and black patients in our cohort, except for rates of abnormal platelet level and diabetes. Physicians should feel comfortable relying on the usual clinical features for the diagnosis of GCA independent of race.

Temporal artery biopsy

Giant cell arteritis is a common vasculitis in patients over the age of 50 years old. If not promptly recognized and aggressively treated with high-dose glucocorticoids, ischemia resulting in permanent vision loss or stroke can occur. Yet, the treatment with high-dose glucocorticoids over a long period of time can be problematic in this particular patient population given their age and associated comorbidities. Temporal artery biopsies (TAB) are an important diagnostic tool to evaluate patients with suspected giant cell arteritis. Herein, we explore indications for TAB and practical points in obtaining a TAB based on available evidence. We review the surgical procedure itself and associated complications. Lastly, we examine common pathological findings and considerations of alternative diagnoses.

Presenting Features of Giant Cell Arteritis with Active Versus Healed Arteritis on Biopsy

Giant cell arteritis (GCA) is often categorised as "active" or "healed" on temporal artery biopsy (TAB). The purpose of this study was to compare the initial clinical presentation of patients with GCA according to active versus healed arteritis on TAB. A retrospective chart review was performed for patients with biopsy-proven GCA (BP-GCA) at a single academic medical institution from a previously reported cohort. The arteritis on TAB was categorised as "active" or "healed" based on the pathological reports. Demographic information, clinical presentation, past medical history, and test results were collected from the date of TAB. These baseline characteristics were entered into the GCA Risk Calculator. Of 85 patients with BP-GCA, 80% had active and 20% had healed disease according to histopathology. A higher percentage of those with active arteritis had ischaemic optic neuropathy (ION) (36% versus 6%, p = .03), elevated erythrocyte sedimentation rates (92% versus 63%, p = .01), elevated C-reactive protein levels (79% versus 46%, p = .049), GCA risk score > 7.5% (99% sensitivity, 100% versus 71%, p < .001), higher mean GCA risk calculator scores (neural network p = .001; logistic regression p = .002). Patients with healed arteritis were less likely to have visual manifestations than the active arteritis group (38% versus 71%, p = .04). Patients with active vasculitis on biopsy had higher rates of ION and elevated inflammatory markers, as well as higher predictive scores from the GCA risk calculator. Further research is needed regarding correlation of biopsy findings and risk of complications or relapses.

Can a Giant Cell Arteritis (GCA) Risk Stratification Score Be Helpful in Clinical Practice?

INTRODUCTION

Giant cell arteritis (GCA) is the most common type of large vessel vasculitis. The diagnosis of GCA is often challenging and there is a difficult balance of over- and underinvestigation. There have been several proposed scoring systems to help clinicians risk stratify patients who may present with suspected GCA.

METHODS

A retrospective cohort study was performed using electronic medical records of patients referred for a temporal artery biopsy (TAB) and temporal artery ultrasound scan (USS) for suspected GCA. All TABs performed at the Royal Wolverhampton NHS Trust between June 2014 and June 2018 and all USS procedures performed between January 2015 and January 2019 were analysed. Patients who undergo a USS for suspected GCA at our centre routinely have scanned bilateral temporal and axillary arteries. Patients were excluded if they already had a previous diagnosis of GCA (and the clinical question was suspected flare), or if there was insufficient information available.

RESULTS

The total number of patients who underwent a confirmatory diagnostic test (either TAB or USS) for suspected GCA was 187. Thirteen of these patients met the exclusion criteria, the remaining 174 patients were included for analysis. A total of 126 of 174 patients underwent a TAB and 63 of 174 had a USS performed; 15 of 174 who had both these were included in the USS cohort because for all these patients, the ultrasound was the first diagnostic test performed. Our results appear to closely mirror the original multi-centre results with regard to the prediction of biopsy-positive GCA, with the centiles closely following those in the inception cohort. Also, 0% of the 'low' risk probability biopsy cohort were misclassified; none had a positive biopsy. However, 8% of the low-risk-probability ultrasound cohort were misclassified, as two had a positive ultrasound.

CONCLUSION

 Our study highlights that a probability score for GCA derived from a large multi-centre cohort of patients who were biopsy positive predicts ultrasound positivity with similar accuracy. Our work reveals that scoring systems are not infallible but can be helpful in guiding clinical decision making.

Giant Cell Arteritis: Updates and Controversies

Abstract

Giant cell arteritis (GCA) is a systemic granulomatous vasculitis affecting the medium and large-size arteries, and may present with a range of ophthalmic findings. This review will cover GCA epidemiology, pathophysiology, clinical presentation, diagnostic workup, and treatment.

Epidemiology and Pathophysiology

GCA is commonly found in elderly patients and individuals of Scandinavian descent. Recent publications suggest it may be more common in African Americans and Hispanics than previously thought. It is very rare in Asian and Middle-Eastern populations, and there is little data regarding African populations. Genetic studies have identified increased risk associated with HLA-DRB1*04. Rather than a response to a specific antigen such as varicella zoster virus, current immunology research suggests that GCA results from changes associated with the aging immune system.

Clinical presentation to Ophthalmology

Arteritic anterior ischemic optic neuropathy is the most common ophthalmic manifestation of GCA, but central or branch retinal artery occlusion, ophthalmic artery occlusion, cranial neuropathies causing diplopia, and more rarely anterior segment ischemia and anisocoria may also occur. Clinical testing including visual field testing, OCT, OCT-A, ICG and fluorescein angiography can be helpful in suggesting a diagnosis in addition to the clinical exam.

Diagnostic Workup

GCA is ultimately a clinical diagnosis, but it is usually supported with lab results, pathology, and/or imaging. Temporal artery biopsy (TAB) remains the gold standard diagnostic test although its sensitivity is debated and practice patterns still vary with respect to sample length and whether unilateral or simultaneous bilateral biopsies are performed. Some studies have reported higher sensitivity of ultrasounds over TAB, with added benefits of time efficiency and cost effectiveness, promoting the diagnostic use of ultrasounds. MRI and even PET CT protocols offer additional options for less invasive diagnostic testing.

Treatment

Vision-threatening GCA is treated acutely with emergent admission for intravenous methylprednisolone, and long-term high dose oral corticosteroids remain the standard of care, despite common and sometimes serious side effects. The use of steroid-sparing alternatives such as tocilizumab is becoming more common and additional agents are being investigated.

Contextualizing temporal arterial magnetic resonance angiography in the diagnosis of giant cell arteritis: a retrospective cohort study

OBJECTIVES

Imaging modalities have become common in evaluating patients for a possible diagnosis of GCA. This study seeks to contextualize how temporal arterial magnetic resonance angiography (TA-MRA) can be used in facilitating the diagnosis of GCA.

METHODS

A retrospective cohort study was performed on patients who had been previously referred to a rheumatologist for evaluation of possible GCA in Hamilton, Ontario, Canada. Data including clinical features, inflammatory markers, imaging, and biopsy results were extracted. Multivariable logistic regression model to predict the diagnosis of GCA. Using these models, the utility of TA-MRA in series with or in parallel to clinical evaluation was demonstrated across the cohort as well as in subgroups defined by biopsy and imaging status.

RESULTS

In total 268 patients had complete data. Those diagnosed with biopsy- and/or imaging-positive GCA were more likely to demonstrate classic features including jaw claudication and vision loss. Clinical multivariable modelling allowed for fair discriminability [receiver operating characteristic (ROC) 0.759, 95% CI: 0.703, 0.815] for diagnosing GCA; there was excellent discriminability in facilitating the diagnosis of biopsy-positive GCA (ROC 0.949, 0.898-1.000). When used in those with a pre-test probability of 50% or higher, TA-MRA had a positive predictive value of 93.0%; in those with a pre-test probability of 25% or less TA-MRA had a negative predictive value of 89.5%.

CONCLUSION

In those with high disease probability, TA-MRA can effectively rule in disease (and replace temporal artery biopsy). In those with low to medium probability, TA-MRA can help rule out the disease, but this continues to be a challenging diagnostic population.

Hyperechogenic intimal lesions and wall thickness of the temporal and facial arteries in elderly patients with arterial occlusions of the eye

OBJECTIVE

To determine the association of arteriosclerosis, characterised by hyperechogenic intimal lesions (HIL), with wall thickness of the temporal and facial arteries in elderly patients with ocular arterial occlusions.

METHODS

Patients suffering from non-arteritic ocular perfusion disorders were included. High-resolution compression sonography (18 MHz) images of the temporal arteries (frontal and parietal branch at the upper margin of the auricle) and facial arteries (at the crossing point of the artery over the mandible) were analysed for the presence of HIL (grade 0: absent; grade 1: moderate; grade 2: severe). Characteristics of patients with and without evidence of HIL >grade 1 were compared.

RESULTS

In total, 330 cranial artery segments of 55 patients were analysed. HIL ≥grade 1 was present in 13.0% of all artery segments and in 38.1% of all patients. Patients with HIL ≥grade 1 in at least one arterial segment displayed significantly increased maximum wall thickness of the temporal arteries (0.62±0.23 mm vs 0.50±0.13 mm; p<0.01) and facial arteries (0.71±0.20 mm vs 0.54±0.19 mm; p=0.01). Patients with at least one temporal or facial artery segment with HIL were older, more often male and more frequently suffered from diabetes mellitus.

CONCLUSION

The presence of HIL goes along with a significantly increased wall thickness of the temporal and facial arteries. These findings should be considered when interpreting the results of sonography of the cranial arteries in the diagnostic workup of suspected giant cell arteritis.

A Diagnostic Algorithm Based on a Simple Clinical Prediction Rule for the Diagnosis of Cranial Giant Cell Arteritis

Background: Risk stratification based on pre-test probability may improve the diagnostic accuracy of temporal artery high-resolution compression sonography (hrTCS) in the diagnostic workup of cranial giant cell arteritis (cGCA). Methods: A logistic regression model with candidate items was derived from a cohort of patients with suspected cGCA (n = 87). The diagnostic accuracy of the model was tested in the derivation cohort and in an independent validation cohort (n = 114) by receiver operator characteristics (ROC) analysis. The clinical items were composed of a clinical prediction rule, integrated into a stepwise diagnostic algorithm together with C-reactive protein (CRP) values and hrTCS values. Results: The model consisted of four clinical variables (age > 70, headache, jaw claudication, and anterior ischemic optic neuropathy). The diagnostic accuracy of the model for discrimination of patients with and without a final clinical diagnosis of cGCA was excellent in both cohorts (area under the curve (AUC) 0.96 and AUC 0.92, respectively). The diagnostic algorithm improved the positive predictive value of hrCTS substantially. Within the algorithm, 32.8% of patients (derivation cohort) and 49.1% (validation cohort) would not have been tested by hrTCS. None of these patients had a final diagnosis of cGCA. Conclusion: A diagnostic algorithm based on a clinical prediction rule improves the diagnostic accuracy of hrTCS.

Aptamers for Proteins Associated with Rheumatic Diseases: Progress, Challenges, and Prospects of Diagnostic and Therapeutic Applications

Nucleic acid aptamers capable of affine and specific binding to their molecular targets have now established themselves as a very promising alternative to monoclonal antibodies for diagnostic and therapeutic applications. Although the main focus in aptamers’ research and development for biomedicine is made on cardiovascular, infectious, and malignant diseases, the use of aptamers as therapeutic or diagnostic tools in the context of rheumatic diseases is no less important. In this review, we consider the main features of aptamers that make them valuable molecular tools for rheumatologists, and summarize the studies on the selection and application of aptamers for protein biomarkers associated with rheumatic diseases. We discuss the progress in the development of aptamer-based diagnostic assays and targeted therapeutics for rheumatic disorders, future prospects in the field, and issues that have yet to be addressed.

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.

Temporal Artery Biopsy in the Workup of Giant Cell Arteritis: Diagnostic Considerations in a Veterans Administration Cohort

BACKGROUND

Giant cell arteritis (GCA) is the most common systemic vasculitis in the American population older than 50 years and is a sight-threatening and life-threatening disease. It is definitively diagnosed with a temporal artery biopsy. Although there are many studies focusing on the clinical presentation and laboratory values in diagnosing GCA in the general population, studies focusing on the veteran population are lacking. This is the first study describing the diagnostic features of GCA in the US military veterans.

METHODS

We performed a retrospective chart review in the Veterans Information Systems and Technology Architecture Computerized Patient Record System (CPRS 1.0, Department of Veterans Affairs Health Data Systems). Anatomic pathology reports from temporal artery biopsies (TABs) were collected, as well as the clinical presentation and laboratory values for each case. Frequency, sensitivity, and specificity were calculated for clinical variables, such as new-onset headache and vision changes, including diplopia, ischemic vision loss/optic disc disease, and amaurosis fugax. A logistic regression (LR) prediction model was then developed to compare veteran risk factors with those of the general population.

RESULTS

Of 292 patients, 40 had positive TABs (13.7%). The average age of subjects with positive TABs was 73 ± 8.8 years (mean ± SD). The average erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) in patients with positive TABs (69.1 mm/hr and 56.6 mg/L, respectively) were significantly higher than ESR and CRP in patients with negative TABs (50.5 mm/hr, P = 0.0016 and 32.2 mg/L, P = 0.0394, respectively). Mean platelet levels were much higher (317.6 × 10/L) in patients with positive TABs than platelet levels in those with negative TABs (260.6 × 10/L, P = 0.0005). CRP was the most sensitive variable at 83.3%, followed by ESR with a sensitivity of 80% and new-onset headache with a sensitivity of 62.5%. Jaw claudication and polymyalgia rheumatica (PMR) were most specific (81.3% and 89.3%, respectively). Headache was the most common presenting symptom overall (71.6%), followed by vision changes (50.3%), scalp tenderness (25.7%), jaw claudication (20.9%), and PMR-related symptoms (12.7%). The LR prediction model included scalp tenderness, log (CRP), log (platelets), vision changes, and age, with 50% sensitivity and 88.36% specificity. Platelets (odds ratio [OR] = 4.309, P = 0.049), CRP (OR = 1.504, P = 0.022) and scalp tenderness (OR = 3.860, P = 0.016) were statistically significant predictors of a positive TAB in this population.

CONCLUSIONS

Veterans Administration (VA) patients present with symptomatology similar to that of the general population. A positive biopsy was found in female veterans more frequently than in their male counterparts. Platelet count and scalp tenderness were most predictive. Our LR model provided a highly specific method for detecting GCA in the veteran population at this institution, but further studies are needed to determine the generalizability of the model. This retrospective study serves as a basis for future multicenter VA-wide studies to characterize the unique features in this population.

A new era for giant cell arteritis

The landscape of the investigation and management of giant cell arteritis (GCA) is advancing. In this review we will outline the recent advances by searching the current English literature for relevant articles using key words of giant cell arteritis, temporal arteritis, Horton's disease, investigation, and treatment. Delay in diagnosis, diagnostic uncertainty and glucocorticoid (GC) morbidity are among the highest concerns of clinicians and patients in this disease area. The positive news is that fast track pathways, imaging techniques and new therapies are emerging for routine management of GCA. Future directions for intervention in the treatment paradigm will be discussed.

Temporal Artery Biopsy for Diagnosing Giant Cell Arteritis: A Ten-year Review

Purpose

To assess the use of temporal artery biopsy (TAB) in diagnosing giant cell arteritis (GCA) and to evaluate patients' clinical and laboratory characteristics.

Methods

We conducted a retrospective chart review of patients with suspected GCA who underwent TAB and had complete workup in a tertiary center in Iran between 2008 and 2017. The 2016 American College of Rheumatology (ACR) revised criteria for early diagnosis of GCA were used for each patient for inclusion in this study.

Results

The mean age of the 114 patients in this study was 65.54 ± 10.17 years. The mean overall score according to the 2016 ACR revised criteria was 4.17 ± 1.39, with 5.82 ± 1.28 for positive biopsies and 3.88 ± 1.19 for negative biopsies (p <0.001). Seventeen patients (14.9%) had a positive biopsy. Although the mean post-fixation specimen length in the biopsy-positive group (18.35 ± 6.9 mm) was longer than that in the biopsy-negative group (15.62 ± 8.4 mm), the difference was not statistically significant (P = 0.21). There was no statistically significant difference between the groups in terms of sex, serum hemoglobin, platelet count, and erythrocyte sedimentation rate. There were statistically significant differences between the biopsy-negative and biopsy-positive groups with respect to patients' age and C-reactive protein level (P< 001 and P = 0.012, respectively).

Conclusion

The majority of TABs were negative. Reducing the number of redundant biopsies is necessary to decrease workload and use of medical services. We suggest that the diagnosis of GCA should be dependent on clinical suspicion.

Giant cell arteritis: a diagnostic challenge in an older adult

Giant cell arteritis is a large-vessel vasculitis usually seen in older adults. The inflammatory process results in systemic, ophthalmic, and neurological lesions. It is difficult to diagnose in older adults and may present as a medical emergency. Here, we report the case of an 83-year-old woman who presented with bitemporal headache, jaw claudication, glossodynia, failure to thrive, and amaurosis fugax. The findings supported the hypothesis of giant cell arteritis. Despite receiving treatment, the patient died of an acute myocardial infarction. Headache in older adults raises the possibility of giant cell arteritis, especially when combined with an ophthalmic emergency. Many symptoms indicate the condition, but the diagnosis may be challenging, especially for the generalist physician.

Ischemic Optic Neuropathy

PURPOSE OF REVIEW

Vision is often threatened or lost by acute ischemic damage to the optic nerves. Such pathology most often affects the anterior portion of the nerve and is visible on funduscopic examination. Ischemic optic neuropathy is associated with typical vascular risk factors and with one systemic disease in particular: giant cell arteritis (GCA). This article provides an overview of the three major classes of ischemic optic neuropathy, including information on risk factors, differential diagnosis, evaluation, and management.

RECENT FINDINGS

Optical coherence tomography provides precise anatomic imaging in ischemic optic neuropathy, showing neural loss weeks before it is visible on examination. Refinements of optical coherence tomography reveal optic nerve microvasculature and may assist in understanding pathogenesis and verifying diagnosis. New diagnostic algorithms and cranial vascular imaging techniques help define the likelihood of GCA in patients with ischemic optic neuropathy. Finally, intraocular drug and biological agent delivery holds promise for nonarteritic ischemic optic neuropathy, whereas newer immunologic agents may provide effective steroid-sparing treatment for GCA.

SUMMARY

It is essential to recognize ischemic optic neuropathy upon presentation, especially to determine the likelihood of GCA and the need for immediate steroid therapy. A broad differential diagnosis should be considered so as not to miss alternative treatable pathology, especially in cases with retrobulbar optic nerve involvement.

Giant cell arteritis: is the clinical spectrum of the disease changing?

BACKGROUND

Giant cell arteritis is a vasculitis of large and middle-sized arteries that affects patients aged over 50 years. It can show a typical clinical picture consisting of cranial manifestations but sometimes nonspecific symptoms and large-vessel involvement prevail. Prompt diagnosis and treatment is essential to avoid irreversible damage.

DISCUSSION

There has been an increasing knowledge on the occurrence of the disease without the typical cranial symptoms and its close relationship and overlap with polymyalgia rheumatica, and this may contribute to reduce the number of underdiagnosed patients. Although temporal artery biopsy is still the gold-standard and temporal artery ultrasonography is being widely used, newer imaging techniques (FDG-PET/TAC, MRI, CT) can be of valuable help to identify giant cell arteritis, in particular in those cases with a predominance of extracranial large-vessel manifestations.

CONCLUSIONS

Giant cell arteritis is a more heterogeneous condition than previously thought. Awareness of all the potential clinical manifestations and judicious use of diagnostic tests may be an aid to avoid delayed detection and consequently ominous complications.

Ultrasound versus temporal artery biopsy in patients with Giant cell arteritis: a prospective cohort study

Background

Diagnosis of giant cell arteritis by temporal artery biopsy is time-consuming and visual loss lies in the first week after its diagnosis. The purpose of the study was to test the hypothesis that ultrasound can reduce the risk of overdiagnosis and overtreatment in giant cell arteritis.

Methods

Data regarding physical/ clinical features examinations, temporal artery biopsy examinations, ultrasound findings, and magnetic resonance imaging examinations of 980 suspected patients for giant cell arteritis were included in the study. Decision curve analysis was applied to get a beneficial score for selected diagnostic modalities. Cost analysis was performed for each patient.

Results

Fewer numbers of false positive giant cell arteritis results were reported under physical/ clinical features examinations following ultrasound detection than physical/clinical features examinations following temporal artery biopsy examinations (45 vs. 127, p < 0.0001). The working area that detects giant cell arteritis at least one time for physical/ clinical features examinations following ultrasound detection and physical/ clinical features examinations following temporal artery biopsy examinations were 0–91% and 0–86%. No significant difference for true negative results between magnetic resonance imaging and physical and clinical features examinations following ultrasound detection (p = 0.007). Physical and clinical features examinations following ultrasound detection were less expensive method than physical/ clinical features examinations following temporal artery biopsy examinations (14,023 ± 982 ¥/patient vs. 18,551 ± 1231 ¥/patient, p < 0.0001) and MRI.

Conclusion

Physical and clinical features examinations following ultrasound are recommended for diagnosis of patients with suspected giant cell arteritis.

The utility of ESR, CRP and platelets in the diagnosis of GCA

Background

To compare the utility of ESR, CRP and platelets for the diagnosis of GCA.

Method

A clinical diagnosis of GCA was determined by case-note review of 270 individuals (68% female, mean age 72 years) referred to a central pathology service for a temporal artery biopsy between 2011 and 2014. The highest levels of ESR, CRP and platelets (within 2 weeks of diagnosis) were documented. Evaluation of ESR, CRP and platelets for the diagnosis of GCA were compared using Receiver Operating Characteristic Area Under the Curve (ROC-AUC), and sensitivity/specificity at optimum cut-off values.

Results

GCA was clinically diagnosed in 139 (67%) patients, with 81 TAB positive. The AUC estimates for ESR, CRP and platelets were comparable (0.65 vs 0.72 vs 0.72, p = 0.08). The estimated optimal cut-off levels were confirmed at 50 mm/hour for ESR, and determined as 20 mg/L for CRP and 300 × 10⁹/L for platelets. Sensitivity estimates for these three tests were comparable (p = 0.45) and ranged between 66% for ESR and 71% for platelets. Specificity estimates were also comparable (p = 0.11) and ranged between 57% for ESR and 68% for CRP. There was only moderate agreement between the three positive tests (agreement 67%, kappa: 0.34), and when considered collectively, CRP and platelet positive tests were independent predictors of GCA (p <  0.001), but the ESR was not (p = 0.76).

Conclusion

ESR, CRP and platelets are moderate, equivalent diagnostic tests for GCA, but may yield disparate results in individual patients. A combination of CRP and platelet tests may provide the best diagnostic utility for GCA.

Neural network and logistic regression diagnostic prediction models for giant cell arteritis: development and validation

PURPOSE

To develop and validate neural network (NN) vs logistic regression (LR) diagnostic prediction models in patients with suspected giant cell arteritis (GCA). Design: Multicenter retrospective chart review.

METHODS

An audit of consecutive patients undergoing temporal artery biopsy (TABx) for suspected GCA was conducted at 14 international medical centers. The outcome variable was biopsy-proven GCA. The predictor variables were age, gender, headache, clinical temporal artery abnormality, jaw claudication, vision loss, diplopia, erythrocyte sedimentation rate, C-reactive protein, and platelet level. The data were divided into three groups to train, validate, and test the models. The NN model with the lowest false-negative rate was chosen. Internal and external validations were performed.

RESULTS

Of 1,833 patients who underwent TABx, there was complete information on 1,201 patients, 300 (25%) of whom had a positive TABx. On multivariable LR age, platelets, jaw claudication, vision loss, log C-reactive protein, log erythrocyte sedimentation rate, headache, and clinical temporal artery abnormality were statistically significant predictors of a positive TABx (P≤0.05). The area under the receiver operating characteristic curve/Hosmer-Lemeshow P for LR was 0.867 (95% CI, 0.794, 0.917)/0.119 vs NN 0.860 (95% CI, 0.786, 0.911)/0.805, with no statistically significant difference of the area under the curves (P=0.316). The misclassification rate/false-negative rate of LR was 20.6%/47.5% vs 18.1%/30.5% for NN. Missing data analysis did not change the results.

CONCLUSION

Statistical models can aid in the triage of patients with suspected GCA. Misclassification remains a concern, but cutoff values for 95% and 99% sensitivities are provided (https://goo.gl/THCnuU).

Systematic Review of the Yield of Temporal Artery Biopsy for Suspected Giant Cell Arteritis

PURPOSE

To determine the positive yield (utility rate) of temporal artery biopsy (TAB) in patients with suspected giant cell arteritis (GCA).

STUDY DESIGN

Systematic review (CRD42017078508) and meta-regression.

MATERIALS AND METHODS

All articles concerning TAB for suspected GCA with English language abstracts from 1998 to 2017 were retrieved. Articles were excluded if they exclusively reported positive TAB, or only cases of known GCA. Where available, the pre-specified predictors of age, sex, vision symptoms, jaw claudication, duration of steroid treatment prior to TAB, specimen length, bilateral TAB, and use of ultrasound/MRI (imaging) were recorded for meta-regression.

RESULTS

One hundred and thirteen articles met eligibility criteria. The I 2 was 92%, and with such high heterogeneity, meta-analysis is unsuitable. The median yield of TAB was 0.25 (95% confidence interval 0.21 to 0.27), with interquartile range 0.17 to 0.34. On univariate meta-regression age (coefficient 0.012, p = 0.025) was the only statistically significant patient factor associated with TAB yield.

CONCLUSIONS

Systematic review revealed high heterogeneity in the yield of TAB. The median utility rate of 25% and its interquartile range provides a benchmark for decisions regarding the under/overutilization of TAB and aids in the evaluation of non-invasive alternatives for the investigation of GCA.

Local anesthesia and anxiolytic techniques for oculoplastic surgery

This study discusses local anesthetic agents, administration techniques, ancillary considerations, and safety precautions for oculoplastic surgery including eyelid, lacrimal, orbital, and temporal artery biopsy procedures. Methods for reducing patient apprehension and discomfort including systemic premedication, topical pre-anesthetic, visual, auditory and tactile distraction techniques, regional blocks, small gauge needles, warmed lidocaine, and buffered lidocaine are discussed.

Support Vector Machines and logistic regression to predict temporal artery biopsy outcomes

OBJECTIVE

Support vector machines (SVM) is a newer statistical method that has been reported to be advantageous to traditional logistic regression for clinical classification. We determine if SVM can better predict the results of temporal artery biopsy (TABx) for giant cell arteritis compared to logistic regression.

METHOD

A database of 530 TABx patients with 10 covariates was used and randomly split into training and test sets. The area under the receiving operating curve (AUC), misclassification rate (MCR), and false negative rate (FN) were compared for SVM and logistic regression. AUC and MCR were used to tune the SVM.

RESULTS

The SVM model with optimal AUC had gamma = 0.01267 and cost = 26.466, with 133 support vectors. The AUC/MCR/FN for logistic regression and SVM respectively were 0.827/0.184/0.524 and 0.825/0.168/0.571.

CONCLUSION

In our dataset of 530 TABx subjects, SVM did not offer any distinct advantage over the logistic regression prediction model.

Recent Advances in Giant Cell Arteritis

PURPOSE OF REVIEW

Giant cell arteritis (GCA) is the most common systemic vasculitis. GCA is categorized as a granulomatous vasculitis of large and medium size vessels. Majority of the symptoms and signs of GCA result from involvement of the aorta and its branches intra- and extracranial. Temporal artery biopsy continues to be the cardinal diagnostic procedure despite new imaging modalities for diagnosing GCA with cranial involvement. Great advances in awareness have led to improvement in preventing irreversible vision loss due to early diagnosis.

RECENT FINDINGS

The cause of GCA has not been elucidated but major progress has been made in the knowledge of its pathogenesis leading to new therapeutic targets, particularly inhibition of interleukin 6. IL 6 plays a key role in the regulation of TH17/Tregs imbalance in GCA and appears to correlate with clinical disease activity in GCA. All of this has led to the first FDA (food and drug administration) approved treatment for GCA, Tocilizumab. Abatacept and Ustekinumab are promising targets for therapy in LVV but still need further research. This paper is a review of the recent progress in the understanding of GCA pathogenesis, diagnosis, treatment, and prognosis.

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.