Sensitivity (95% CI)a
Specificity (95% CI)a
PPV (95% CI)a
NPV (95% CI)a
Overall accuracy (95% CI)a
Consensus normal stenosis
100 (100, 100)
100 (100, 100)
100 (100, 100)
100 (100, 100)
100 (100, 100)
Consensus < 50% stenosis
88 (83.6, 91.7)
99 (95.6, 100)
100 (98.7, 100)
68 (58.8, 77.3)
90 (84, 95.9)
Consensus 50 to <70% stenosis
93 (89.3, 96.1)
68 (58.5, 76.9)
86 (82, 90.8)
81 (72.2, 89.2)
85 (77.2, 92.6)
Consensus ≥ 70% stenosis
99 (97.7, 100)
86 (80, 92.8)
93 (89.9, 96.5)
98 (95.1, 100)
95 (90.2, 99.1)
Table 19.2 summarizes the Pearson overall correlation of the consensus criteria to angiographic stenosis and the correlation to 70–99% stenosis. As seen in this table, which shows the four variables considered in the consensus criteria (ICA PSV, ICA EDV, ICA/CCA systolic ratio, and the ICA/CCA diastolic ratio), the PSV has the best overall correlation to angiography (0.813) and also the best correlation for the diagnosis of 70–99% stenosis (0.833).
Table 19.2
Pearson correlation of the consensus criteria for PSV, EDV, systolic ratio, and diastolic ratio to angiography
Duplex variable | Overall correlation (95% CI)a | Correlation to ≥70 to 99% stenosis (95% CI)a |
|---|---|---|
Peak systolic velocity | 0.81 (0.77, 0.85) | 0.833 (0.8, 0.86) |
End-diastolic velocity | 0.7 (0.64, 0.75) | 0.755 (0.71, 0.80) |
Systolic ratio | 0.57 (0.49, 0.63) | 0.601 (0.53, 0.66) |
Diastolic ratio | 0.54 (0.46, 0.61) | 0.60 (0.53, 0.66) |
When applying the Kappa statistic and using the PSV cutoff defined by the consensus criteria and compared to angiography, the simple Kappa was 0.6870 (95% confidence interval of 0.623–0.750), with a weighted Kappa of 0.758 (95% confidence interval of 0.705–0.810). This is in contrast to a simple Kappa of 0.535 (95% confidence interval of 0.461–0.609), with a weighted Kappa of 0.630 (95% confidence interval of 0.565–0.695) when using the EDV cutoff value.
Table 19.3 summarizes various PSVs, EDVs, systolic ratios, and diastolic ratios as a single parameter or in combination for detecting ≥70 to 99% stenosis. As noted in this table, a PSV of >230 cm/s was most sensitive in diagnosing ≥70 to 99% stenosis. It should also be noted that a PSV > 280 cm/s had a better PPV (97%) and overall accuracy (95%); however, the sensitivity was down to 95% and the NPV was 89%. When the PSV was >230 with an EDV > 100 or systolic ratio > 4, the sensitivity was 91% and the specificity was 97%; however, the PPV was 99%, the NPV was 78%, and then overall accuracy was 93%.
Table 19.3
Summary of various velocities and ratios for detecting ≥70 to 99% stenosis
Sensitivity | Specificity | PPV | NPV | Overall accuracy | |
|---|---|---|---|---|---|
PSV > 230 | 99 (97, 100) | 86 (79.8, 92.7) | 93 (89.9, 96.5) | 97 (93.5, 100) | 94 (89.7, 98.9) |
PSV > 240 | 97 (95, 99.4) | 87 (80.2, 93.2) | 94 (90.5, 96.9) | 94 (89.0, 98.6) | 94 (88.9, 98.5) |
PSV > 280 | 95 (92.3, 97.9) | 93 (88.4, 98.5) | 97 (95.1, 99.4) | 89 (82.4, 95) | 95 (90.2, 99.1) |
Systolic ratio > 2.75 | 87 (82.8, 91.3) | 85 (76.6, 92.6) | 95 (91.6, 97.6) | 68 (58.8, 77.3) | 86 (79.7, 93.3) |
Systolic ratio > 3 | 86 (81.3, 90) | 91 (84.2, 97.9) | 97 (95.1, 99.4) | 63 (53.3, 72.5) | 87 (80.1, 93.5) |
Diastolic ratio > 3 | 87 (82.6, 91.2) | 80 (71.9, 89.1) | 93 (89.3, 96.2) | 68 (58.8, 77.3) | 85 (78.2, 92.3) |
Diastolic ratio > 3.5 | 86 (81.9, 90.5) | 89 (81.4, 96.1) | 96 (93.9, 98.8) | 65 (55.5, 74.4) | 87 (80.1, 93.5) |
PSV > 230 and EDV > 50 | 97 (95.0, 99.4) | 88 (82.2, 94.6) | 95 (91.6, 97.6) | 94 (89, 98.6) | 94 (89.7, 98.9) |
PSV > 230 and/or EDV > 90 | 99 (97, 100) | 86 (79.8, 92.7) | 93 (89.9, 96.5) | 97 (93.5, 100) | 94 (89.7, 98.9) |
PSV > 220 and diastolic ratio > 2.5 | 88 (84.2, 92.4) | 87 (80, 94.7) | 95 (92.7, 98.2) | 71 (62.1, 80.2) | 88 (81.6, 94.5) |
PSV > 230 and/or diastolic ratio > 5.5 | 99 (97, 100) | 86 (79.8, 92.7) | 93 (89.9, 96.5) | 97 (93.5, 100) | 94 (89.7, 98.9) |
PSV > 220 and systolic ratio > 2.5 | 89 (84.8, 92.8) | 91 (84.5, 97.3) | 97 (94.5, 99.1) | 72 (63.3, 81.1) | 89 (83.2, 95.5) |
PSV > 230 and/or systolic ratio > 4.5 | 99 (96.9, 100) | 85 (78.9, 92) | 93 (89.3, 96.2) | 97 (93.5, 100) | 94 (89.3, 98.7) |
EDV > 50 and systolic ratio > 2.5 | 88 (84.3, 92.4) | 88 (81.4, 95.6) | 96 (93.3, 98.5) | 71 (62.1, 80.2) | 88 (82, 94.8) |
EDV > 70 and/or systolic ratio > 4 | 97 (94.2, 99.1) | 83 (76.3, 90.4) | 92 (88.3, 95.5) | 93 (87.6, 97.9) | 92 (86.8, 97.5) |
EDV > 100 and/or systolic ratio > 4 | 91 (87.6, 94.8) | 96 (92, 100) | 99 (97, 100) | 78 (70, 86.6) | 92 (87.2, 97.7) |
PSV > 230 and (EDV > 100 or systolic ratio > 4) | 91 (87.7, 94.8) | 97 (93.9, 100) | 99 (97.9, 100) | 78 (70.2, 86.6) | 93 (87.6, 97.9) |
Systolic ratio > 2 and diastolic ratio > 3.5 | 86 (81.6, 90.3) | 90 (82.7, 97) | 97 (94.5, 99.1) | 64 (54.4, 73.5) | 87 (80.1, 93.5) |
Systolic ratio > 3.5 and/or diastolic ratio > 3 | 87 (83.2, 91.7) | 78 (69.5, 86.8) | 91 (87.7, 95.1) | 70 (61, 79.2) | 85 (77, 8.92) |
CI confidence interval, EDV end-diastolic velocity, NPV negative predictive value, PPV positive predictive value, PSV peak systolic velocity. Bold values are the values with the best combined sensitivity, specificity, and overall accuracy
From AbuRahma AF, et al. Critical appraisal of the Carotid Duplex Consensus criteria in the diagnosis of carotid artery stenosis. J Vasc Surg. 2011;53:53–60. Reprinted with permission from Elsevier
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
