Specific parameters:
E/A: The overall correlation between E/A and PCWP (graph 1) was weak with a Pearson correlation coefficient of 0.27(p =0.005).As per guidelines, E/A <1 is associated with normal LAP. In our study series, 2 patients had PCWP ≥15 even though E/A <1, this indicates a sensitivity of 16.7% and specificity of 61.4% in detecting elevated PCWP. E/A >2 is associated with elevated LAP. In our study ,4 patients had PCWP <15 even though E/A >2 which indicates a sensitivity of 33.3% and specificity of 95.5% in identifying elevated PCWP.
E/A,1-2 is indeterminate in detecting elevated PCWP. In our study E/A,1-2 had a sensitivity of 50% and specificity of 43.2% in detecting elevated PCWP.
DT: The correlation between DT and PCWP (Graph 2) was demonstrated to be weak with a Pearson correlation coefficient of -0.064 (p =0.526).The area under the ROC curve for using DT to predict elevated PCWP (≥15mmHg) is 0.47 (C.I: 0.31-0.63). Maximising the specificity, the optimum threshold value of DT to predict elevated PCWP (≥15 mm Hg) is 196 with a sensitivity of 8.3% and specificity of 80.7% with accuracy of 72%. Maximising the sensitivity, the optimum threshold value of DT to predict elevated PCWP (≥15 mm Hg) is 116.5 with a sensitivity of 83.3% and specificity of 23.9 % with accuracy of 31%.
S/D: The correlation between S/D and PCWP was weak with a pearson correlation coefficient of -0.086 (p =0.393).As per guidelines, S/D<1 is associated with elevated LAP. In our study,21 patients had PCWP <15 even though S/D <1 showing a sensitivity of 58.3% and specificity of 76.1% in detecting elevated PCWP.
SF RATIO: The correlation between SF ratio and PCWP (Graph 4) is weak with a pearson correlation coefficient of -0.143 (p =0.393).The area under the ROC curve for using SF ratio to predict elevated PCWP (≥15mmHg) is 0.35 (C.I: 0.14 - 0.57). Maximising the specificity, the optimum threshold value of SF ratio to predict elevated PCWP (≥15 mm Hg) is 0.6 with a sensitivity of 25% and specificity of 81.8% with accuracy of 75%.Maximising the sensitivity, the optimum threshold value of SF ratio to predict elevated PCWP (≥15 mm Hg) is 0.39 with a sensitivity of 83.3% and specificity of 2.3 % with accuracy of 12%.
E/Ea: The correlation between E/Ea ratio and PCWP (Graph 5)is weak with a pearson correlation coefficient of 0.181 (p =0.071).The area under the ROC curve for using E/Ea to predict elevated PCWP (≥15mmHg) is 0.79 (C.I: 0.67- 0.92).
Maximising the specificity,the optimum threshold value of E/Ea to predict elevated PCWP (≥15 mm Hg)
(Graph 4) is 11.55 with a sensitivity of 50% and specificity of 84.1% with accuracy of 80.
Maximising the sensitivity, the optimum threshold value of E/Ea to predict elevated PCWP(≥15 mm Hg) is 9.2 with a sensitivity of 91.7% and specificity of 63.6%with accuracy of 67%.
Guidelines suggest that an E/Ea>14 is associated with elevated PCWP. In our series, an E/Ea>14 had a sensitivity of 33.3% and specificity of 93.2% with accuracy of 86 to detect an elevated PCWP ≥15 mm Hg.
E/Vp : The correlation between E/Vp ratio and PCWP (Graph 6) is weak with a pearson correlation coefficient of 0.221 (p =0.027).Guidelines suggest that an E/Vp>2.5 is associated with elevated PCWP. In our study series, 9 patients had PCWP<15 with E/ Vp> 2.5, showing a sensitivity of 33.3% and specificity of 89.8% to detect an elevated PCWP ≥15 mm Hg.