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)
Monophasic, or absent, or any biphasic0.930.871.
Monophasic or any biphasic with adverse features0.910.840.990.250.140.350.520.420.620.760.580.941.211.031.420.350.140.90
Monophasic or absent0.780.670.880.400.280.520.540.430.640.670.520.811.291.021.650.560.320.98
ABPI (n=110)
≤0.9 or absent signal in both vessels0.390.250.520.640.520.760.460.310.620.570.450.681.080.661.750.950.721.28
≤0.7 or absent signal in both vessels0.290.160.410.740.630.850.470.290.650.560.450.671.090.592.010.970.771.22
≤0.5 or absent signal in both vessels0.220.110.340.800.700.900.480.270.680.560.460.671.140.552.360.970.791.17
≤0.3 or absent signal in both vessels0.
Ankle pressure (n=110)
≤90 mm Hg or absent signal in both vessels0.940.871.
≤70 mm Hg or absent signal in both vessels0.880.790.970.
≤50 mm Hg or absent signal in both vessels0.860.760.960.
≤30 mm Hg or absent signal in both vessels0.840.730.940.
TBPI (n=70)
Toe pressure (n=70)
≤80 mm Hg0.880.741.
≤60 mm Hg0.710.530.890.390.250.530.380.240.520.720.540.901.160.821.640.750.361.53
≤40 mm Hg0.460.260.660.500.360.640.320.170.480.640.480.800.920.541.551.080.681.73
≤20 mm Hg0.250.080.420.610.470.750.250.080.420.610.470.750.640.291.401.230.891.71
TcPO2 (n=116)
TcPO2 at rest (≤80 mm Hg)0.960.921.
TcPO2 at rest (≤60 mm Hg)0.790.680.890.280.170.400.510.400.610.590.410.771.100.891.350.760.401.44
TcPO2 at rest (≤40 mm Hg)0.430.300.560.700.580.820.570.420.720.570.450.681.430.872.330.820.621.08
TcPO2 at rest (≤20 mm Hg)
  • 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.