Nailfold Capillaroscopy in Systemic Sclerosis: How Many Fingers Should be Examined to Detect Abnormality?

Graham Dinsdale¹, Tonia Moore², Neil O’Leary³, Michael Berks⁴, Chris Roberts³, Joanne Manning², John Allen⁵, Marina E Anderson⁶, Maurizio Cutolo⁷, Roger Hesselstrand⁸, Kevin Howell⁹, Carmen Pizzorni⁷, Vanessa Smith¹⁰, Alberto Sulli¹¹, Marie Wildt⁸, Christopher Taylor⁴, Andrea Murray¹ and Ariane L. Herrick^1,12, ¹Division of Musculoskeletal & Dermatological Sciences, University of Manchester, Salford Royal Hospital NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, UK, Manchester, United Kingdom, ²Salford Royal Hospital NHS Foundation Trust, Salford, UK, Salford, United Kingdom, ³Centre for Biostatistics, Division of Population Health, Health Services Research & Primary Care, University of Manchester, Manchester, UK, Manchester, United Kingdom, ⁴Centre for Imaging Sciences, Division of Informatics, Imaging & Data Sciences, University of Manchester, Manchester, UK, Manchester, United Kingdom, ⁵Microvascular Diagnostics, Northern Medical Physics and Clinical Engineering, Freeman Hospital, Newcastle upon Tyne, UK, Newcastle upon Tyne, United Kingdom, ⁶Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, UK, Liverpool, United Kingdom, ⁷Research Laboratory and Academic Unit of Clinical Rheumatology, Department of Internal Medicine, University of Genova, Genova, Italy, Genova, Italy, ⁸Department of Clinical Sciences, Section of Rheumatology, Lund University, Lund, Sweden, Lund, Sweden, ⁹Institute of Immunity and Transplantation, University College London, Royal Free Campus, London, UK, London, United Kingdom, ¹⁰Department of Rheumatology, Ghent University Hospital, Faculty of Internal Medicine, Ghent University, Ghent, Belgium, Ghent, Belgium, ¹¹Research Laboratory and Academic Unit of Clinical Rheumatology, Department of Internal Medicine, University of Genova, Genova, Italy, Genoa, Italy, ¹²NIHR Manchester Musculoskeletal Biomedical Research Unit, Central Manchester NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, UK, Manchester, United Kingdom

Meeting: 2017 ACR/ARHP Annual Meeting

Date of first publication: September 18, 2017

Keywords: nailfold capillaroscopy and systemic sclerosis

Session Information

Date: Tuesday, November 7, 2017

Title: Imaging of Rheumatic Diseases Poster II

Session Type: ACR Poster Session C

Session Time: 9:00AM-11:00AM

Background/Purpose: Nailfold capillaroscopy plays an important role in diagnosing systemic sclerosis (SSc), with abnormal nailfold capillary appearance being included in the 2013 ACR/EULAR diagnostic criteria [1]. Common queries from clinicians who assess patients with suspected SSc are: which finger(s) should be imaged, and how many digits in total, given that assessing 8 fingers (excluding thumbs) takes time in a busy clinical practice? Our aim was to demonstrate the sensitivity of assessing different (combinations of) fingers for the presence of two markers of capillary abnormality: (1) presence of giant capillaries, and (2) overall image grade, compared to assessment of all 8 fingers.

Methods:

Nailfold images (all fingers from each of 101 patients with SSc) and subsequent multi-observer assessments from a large study of quantitative capillaroscopy [2] were characterised by digit. Using custom software, observers counted giant vessels and graded the image overall (including normal/early/active/late). Patients were defined as “true case” for each of 2 parameters (giants, and image grade) if at least one of 8 fingers tested positive for the parameter (i.e. ≥ 1 giant vessels in one or more fingers, or one or more fingers given an ‘abnormal’ [early/active/late] grade). Seven single-finger, or finger combinations (derived from the middle and ring fingers), were then tested for sensitivity of achieving the correct result against the 8-finger “gold standard” true cases.

Results:

For each of seven combinations of finger(s), sensitivity percentages for the two parameters are shown in Table 1. For the 8-finger “gold standard”, sensitivity against the diagnostic criteria was 53.0% (71 +ve cases from 134 assessments) and 73.1% (98 +ve cases from 134 assessments) for presence of giants and image grade, respectively. Pairs of fingers have higher sensitivity than single fingers in all cases, and the 4-finger combination shows a sensitivity of 85.9% and 91.8% for giants and image grade, respectively.

Conclusion:

1. Assessing only middle and ring fingers on both hands detects abnormality in 85-90% of cases of established SSc (halving imaging time).

2. Assessing only ring fingers (sensitivity 73-80%) brings a 75% reduction in imaging time.

3. Some cases of abnormality will be missed by not examining all fingers.

References

Van den Hoogen F, Khanna D, Fransen J, et al. Ann Rheum Dis 2013; 72: 1747-55.
Dinsdale G, Moore T, O’Leary N, et al. Microvascular Res 2017; 112: 1-6.

Table 1. Sensitivity values for two nailfold capillary parameters (presence of giants, and image grade).

	Presence of giant capillaries (71 assessments from 42 patients)		Abnormal image grade (98 assessments from 58 patients)
Finger(s)	Frequency	(%)	Frequency	(%)
Ring Left	40	56.3	63	64.3
Ring Right	32	45.1	58	59.2
Either Ring	52	73.2	79	80.6
Middle Left	32	45.1	55	56.1
Middle Right	23	32.4	44	44.9
Either Middle	40	56.3	72	73.5
Any Middle or Ring	61	85.9	90	91.8

Disclosure: G. Dinsdale, None; T. Moore, None; N. O’Leary, None; M. Berks, None; C. Roberts, None; J. Manning, None; J. Allen, None; M. E. Anderson, None; M. Cutolo, None; R. Hesselstrand, None; K. Howell, None; C. Pizzorni, None; V. Smith, None; A. Sulli, None; M. Wildt, None; C. Taylor, None; A. Murray, None; A. L. Herrick, None.

To cite this abstract in AMA style:

Dinsdale G, Moore T, O’Leary N, Berks M, Roberts C, Manning J, Allen J, Anderson ME, Cutolo M, Hesselstrand R, Howell K, Pizzorni C, Smith V, Sulli A, Wildt M, Taylor C, Murray A, Herrick AL. Nailfold Capillaroscopy in Systemic Sclerosis: How Many Fingers Should be Examined to Detect Abnormality? [abstract]. Arthritis Rheumatol. 2017; 69 (suppl 10). https://acrabstracts.org/abstract/nailfold-capillaroscopy-in-systemic-sclerosis-how-many-fingers-should-be-examined-to-detect-abnormality/. Accessed .

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