CARDIOVASCULAR JOURNAL OF AFRICA • Volume 33, No 3, May/June 2022 132 AFRICA and 89.6% specificity. However, the value of 79.00 showed 88.1% sensitivity and 44.8% specificity. ROC curve analyses of V values are given in Fig. 3 (right leg) and Fig. 4 (left leg). The right-sided pathologies with a value of 6.57 showed 86.9% sensitivity and 82.3% specificity. The leftsided pathologies with a value of 6.77 showed 82.2% sensitivity and 97.1% specificity. ROC curve analyses of EV4/V values are given in Fig. 5 (right leg) and Fig. 6 (left leg). The right-sided pathologies with a value of 0.57 showed 76.9% sensitivity and 82.3% specificity. The leftsided pathologies with a value of 0.54 showed 87.6% sensitivity and 25.8% specificity. However, the value of 0.56 showed 70.8% sensitivity and 80.2% specificity. ROC curve analyses of RV values are given in Fig. 7 (right leg) and Fig. 8 (left leg). The right-sided pathologies with a value of 1.09 showed 78.2% sensitivity and 96.7% specificity. The leftsided pathologies with a value of 1.09 showed 75.2% sensitivity and 52.3% specificity. ROC curve analyses of t½ values are given in Fig. 9 (right leg) and Fig. 10 (left leg). The right-sided pathologies with a value of 5.25 showed 68.9% sensitivity and 99.7% specificity. The leftsided pathologies with a value of 5.40 showed 78.3% sensitivity and 99.3% specificity. Discussion This study reveals that SGP can be used as an effective method for the diagnosis and follow up of CVD. It may become an alternative diagnostic tool for clinicians who have limited access to a radiology service or require additional information, obtained by imaging techniques. A detailed assessment of plethysmographic measurements in this study, with the largest Table 9. Comparing plethysmography measurements of right- and left-sided pathologies in different disease onsets Disease onset VE (R) VE (L) V (R) V (L) EV4/V (R) EV4/V (L) RV (R) RV (L) t½ (R) t½ (L) Acute Average 83.19 82.70 6.52 6.71 0.57 0.60 1.14 1.12 5.46 6.09 Number 94 75 94 75 94 75 94 75 94 75 SD 4.13 3.05 0.12 0.05 0.04 0.03 0.12 0.01 0.74 .93 Median 83.00 84.00 6.55 6.75 0.56 0.60 1.10 1.12 5.00 6.00 Minimum 72.00 74.00 6.30 6.60 0.49 0.55 1.00 1.08 5.00 5.80 Maximum 100.00 89.00 7.00 6.80 0.77 0.75 1.60 1.15 9.00 14.00 Chronic Average 97.22 96.01 6.38 6.38 0.68 0.71 1.46 1.53 7.05 7.79 Number 109 105 109 105 109 105 109 105 109 105 SD 7.02 6.83 0.10 0.16 0.05 0.06 0.12 0.12 1.11 1.48 Median 98.00 94.00 6.35 6.35 0.68 0.70 1.50 1.60 6.50 7.00 Minimum 78.00 80.00 6.20 6.15 0.55 0.55 1.05 1.05 5.00 5.00 Maximum 108.00 115.00 6.78 6.78 0.80 0.82 1.60 1.65 10.00 10.00 Acute exacerbation on chronic onset Average 72.00 78.28 7.00 6.80 0.50 0.52 1.00 1.03 5.00 5.00 Number 3 46 3 46 3 46 3 46 3 46 SD 3.60 5.83 0.00 0.08 0.00 0.01 0.00 0.02 0.00 0.00 Median 71.00 79.00 7.00 6.80 0.50 0.52 1.00 1.05 5.00 5.00 Minimum 69.00 66.00 7.00 6.74 0.50 0.49 1.00 1.00 5.00 5.00 Maximum 76.00 88.00 7.00 7.00 0.50 0.55 1.00 1.05 5.00 5.00 p-value* 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 *Kruskal–Wallis test. VE: venous emptying, V: venous volume, EV4/V: expelled volume ratio in four seconds, RV: refilling volume, t½: half refilling time, R: right, L: left, SD: standard deviation. Table 10. Correlation analyses between half refilling time (t½) and the presence of oedema or skin discolouration in the affected limb Pathologies Rank correlation coefficient (r) p-value* Right-sided pathology Presence of oedema –0.045 0.524 Presence of skin discolouration –0.384 0.000 Left-sided pathology Presence of oedema –0.310 0.000 Presence of skin discoluoration –0.263 0.000 *Spearman’s correlation test. 0,0 0,2 0,4 0,6 0,8 1,0 1 – Specificity Diagonal segments are produced by ties. Sensitivity 1,0 0,8 0,6 0,4 0,2 0,0 Fig. 2. ROC curve of venous emptying (VE) measurements of left-sided pathology. 0,0 0,2 0,4 0,6 0,8 1,0 1 – Specificity Diagonal segments are produced by ties. Sensitivity 1,0 0,8 0,6 0,4 0,2 0,0 Fig. 3. ROC curve of venous volume (V) measurements of right-sided pathology.
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