Table 1.

Characteristics of included studies. ACR: American College of Rheumatology; EULAR: European League against Rheumatism; N/A: Not available; NFC: Nailfold capillaroscopy rating scale score; NVC: Nailfold video-capillaroscopy; PAH: Pulmonary arterial hypertension; RHC: Right heart catheterization; SSc: Systemic Sclerosis; SSc-noPAH: Systemic sclerosis without pulmonary arterial hypertension; SSc-PAH: Systemic sclerosis with Pulmonary arterial hypertension; TTE: Transthoracic echocardiography; VDS: Vascular deletion score.

Study	Study Design	SSc Criteria	Population		Mean Disease Duration (Years)		Method of PAH Diagnosis	Nailfold Capillaroscopy Method	Capillaroscopy Parameters
			SSc- PAH	SSc-noPAH	SSc- PAH	SSc-noPAH
Corrado et al. 2017 [36]	Cross-sectional	ACR/EULAR 2013 diagnostic criteria for SSc [11]	19	20	15.3 ± 3.9	18.4 ± 4.1	RHC	NVC, 200× magnification	Capillary density Capillary dimensions Neoangiogenesis Pattern
Hofstee et al. 2009 [35]	Cross-sectional	preliminary criteria for the classification of SSc 1980 [43]	21	19	3.7 ± 12.3	3.7 ± 9.8	RHC	computer-based panorama mosaic NVC	Capillary density Capillary dimensions
Guillén-Del-Castillo et al. 2018 [40]	Cross-sectional	ACR/EULAR 2013 diagnostic criteria for SSc [11]	11	123	N/A		RHC	NVC, 200× magnification	Capillary density Capillary dimensions Microhemorrhages Neoangiogenesis Pattern
Sato et al. 2009 [39]	Cross-sectional	preliminary criteria for the classification of SSc 1980 [43]	10	71	N/A		TTE	microscopy 10–20× magnification	Capillary density Capillary dimensions VDS
Ong et al. 1998 [38]	Cross-sectional	Not defined	8	12	22.9 ± 16.6	18.1 ± 10.2	TTE and/or RHC	microscopy 60× magnification	Capillary density Capillary dimensions
Riccieri et al. 2013 [25]	Cross-sectional	preliminary criteria for the classification of SSc 1980 [43]	12	12	24.4 ± 17.6	18.9 ± 10.7	RHC	NVC, 200× magnification	Pattern VDS NFC
Hammoda et al. 2020 [37]	Cross-sectional	ACR/EULAR 2013 diagnostic criteria for SSc [11]	20	20	21.4 ± 10.4	9.3 ± 6.5	RHC	NVC, 200× magnification	Capillary density Capillary dimensions VDS Microhemorrhages Pattern NFC
Meier et al. 2012 [32]	Cross-sectional	Not defined	10	37	N/A		Not defined	NVC	Capillary density Capillary dimensions
Bredemeier et al. 2004 [33]	Cross-sectional	preliminary criteria for the classification of SSc 1980 [43]	11	75	N/A		TTE	microscopy 6.5–65× magnification	Capillary dimensions VDS Microhemorrhages
Greidinger et al. 2001 [34]	Cross-sectional	Not defined	8	7	N/A		TTE and/or RHC	microscopy	Capillary density Neoangiogenesis
Avouac et al. 2017 [42]	Longitudinal	ACR/EULAR 2013 diagnostic criteria for SSc [11]	8	132	9 ± 8	9 ± 8	RHC	NVC, 200× magnification	Capillary density Capillary dimensions Microhemorrhages Neoangiogenesis
Sulli et al. 2012 [41]	Longitudinal	preliminary criteria for the classification of SSc 1980 [43] or LeRoy criteria for the classification of early SSc [44]	4	34	N/A		RHC	NVC, 200× magnification	Capillary dimensions Microhemorrhages Capillary ramifications Pattern NFC