Table 2

Summary of prognostic performance comparing PAD-scan, ABPI, ankle pressure, TBPI, toe pressure and TcPO₂

No healing
	Sensitivity	CI (lower)	Cl (upper)	Specificity	CI (lower)	Cl (upper)	PPV	CI (lower)	Cl (upper)	NPV	CI (lower)	Cl (upper)	PDLR	CI (lower)	Cl (upper)	NDLR	CI (lower)	Cl (upper)
PAD-scan
Monophasic, or absent, or any biphasic	0.93	0.87	1.00	0.08	0.01	0.14	0.47	0.38	0.57	0.56	0.23	0.88	1.01	0.91	1.11	0.90	0.25	3.18
Monophasic or any biphasic with adverse features	0.91	0.84	0.99	0.25	0.14	0.35	0.52	0.42	0.62	0.76	0.58	0.94	1.21	1.03	1.42	0.35	0.14	0.90
Monophasic or absent	0.78	0.67	0.88	0.40	0.28	0.52	0.54	0.43	0.64	0.67	0.52	0.81	1.29	1.02	1.65	0.56	0.32	0.98
ABPI (n=110)
≤0.9 or absent signal in both vessels	0.39	0.25	0.52	0.64	0.52	0.76	0.46	0.31	0.62	0.57	0.45	0.68	1.08	0.66	1.75	0.95	0.72	1.28
≤0.7 or absent signal in both vessels	0.29	0.16	0.41	0.74	0.63	0.85	0.47	0.29	0.65	0.56	0.45	0.67	1.09	0.59	2.01	0.97	0.77	1.22
≤0.5 or absent signal in both vessels	0.22	0.11	0.34	0.80	0.70	0.90	0.48	0.27	0.68	0.56	0.46	0.67	1.14	0.55	2.36	0.97	0.79	1.17
≤0.3 or absent signal in both vessels	0.12	0.03	0.21	0.92	0.85	0.99	0.55	0.25	0.84	0.57	0.47	0.66	1.49	0.48	4.60	0.96	0.84	1.09
Ankle pressure (n=110)
≤90 mm Hg or absent signal in both vessels	0.94	0.87	1.00	0.03	0.00	0.08	0.44	0.34	0.53	0.40	0.00	0.83	0.97	0.89	1.06	1.87	0.32	10.74
≤70 mm Hg or absent signal in both vessels	0.88	0.79	0.97	0.07	0.00	0.13	0.43	0.33	0.53	0.40	0.10	0.70	0.94	0.83	1.06	1.87	0.56	6.25
≤50 mm Hg or absent signal in both vessels	0.86	0.76	0.96	0.07	0.00	0.13	0.42	0.33	0.52	0.36	0.08	0.65	0.92	0.80	1.05	2.18	0.68	7.02
≤30 mm Hg or absent signal in both vessels	0.84	0.73	0.94	0.11	0.03	0.19	0.43	0.33	0.53	0.47	0.21	0.72	0.95	0.81	1.10	1.42	0.55	3.65
TBPI (n=70)
≤0.8	0.79	0.63	0.95	0.50	0.36	0.64	0.45	0.30	0.60	0.82	0.68	0.96	1.58	1.11	2.26	0.42	0.18	0.96
≤0.6	0.54	0.34	0.74	0.72	0.59	0.85	0.50	0.31	0.69	0.75	0.62	0.88	1.92	1.06	3.46	0.64	0.40	1.02
≤0.4	0.25	0.08	0.42	0.85	0.74	0.95	0.46	0.19	0.73	0.68	0.56	0.80	1.64	0.62	4.34	0.88	0.68	1.15
≤0.2	0.17	0.02	0.32	0.98	0.94	1.00	0.80	0.45	1.00	0.69	0.58	0.80	7.67	0.91	64.84	0.85	0.71	1.02
Toe pressure (n=70)
≤80 mm Hg	0.88	0.74	1.00	0.20	0.08	0.31	0.36	0.24	0.49	0.75	0.51	0.99	1.09	0.88	1.34	0.64	0.19	2.14
≤60 mm Hg	0.71	0.53	0.89	0.39	0.25	0.53	0.38	0.24	0.52	0.72	0.54	0.90	1.16	0.82	1.64	0.75	0.36	1.53
≤40 mm Hg	0.46	0.26	0.66	0.50	0.36	0.64	0.32	0.17	0.48	0.64	0.48	0.80	0.92	0.54	1.55	1.08	0.68	1.73
≤20 mm Hg	0.25	0.08	0.42	0.61	0.47	0.75	0.25	0.08	0.42	0.61	0.47	0.75	0.64	0.29	1.40	1.23	0.89	1.71
TcPO₂ (n=116)
TcPO₂ at rest (≤80 mm Hg)	0.96	0.92	1.00	0.03	0.00	0.08	0.48	0.39	0.57	0.50	0.01	0.99	1.00	0.93	1.07	1.07	0.16	7.35
TcPO₂ at rest (≤60 mm Hg)	0.79	0.68	0.89	0.28	0.17	0.40	0.51	0.40	0.61	0.59	0.41	0.77	1.10	0.89	1.35	0.76	0.40	1.44
TcPO₂ at rest (≤40 mm Hg)	0.43	0.30	0.56	0.70	0.58	0.82	0.57	0.42	0.72	0.57	0.45	0.68	1.43	0.87	2.33	0.82	0.62	1.08
TcPO₂ at rest (≤20 mm Hg)	0.09	0.01	0.16	0.97	0.92	1.00	0.71	0.38	1.00	0.53	0.44	0.63	2.68	0.54	13.25	0.94	0.86	1.04

ABPI, ankle brachial pressure index; NDLR, negative diagnostic likelihood ratio; NPV, negative predictive value; PAD-scan, podiatry ankle duplex scan; PDLR, positive diagnostic likelihood ratio; PPV, positive predictive value; TBPI, toe brachial pressure index; TcPO₂, transcutaneous pressure of oxygen.