# Clinical Validation of a New Enhanced Stent Imaging Method
## 3 Results
### ESI Image Quality Evaluation  
Table 3 shows the evaluation results of the two observers. The proximal and distal edge visualization grades did not differ between the two observers (1.42 \(\pm\) 0.77 vs. 1.38 \(\pm\) 0.62 and 1.46 \(\pm\) 0.76 vs. 1.44 \(\pm\) 0.61 for observer 1 and 2, respectively); however, a statistically significant difference (\(p\) < 0.05) was found between the mean total grade from observer 1 vs. observer 2 (4.12 \(\pm\) 1.73 vs. 3.67 \(\pm\) 1.49, respectively) for the evaluation of SB images \begin{table}
\begin{tabular}{l r} \hline \hline  & **N** \\ \hline Number of patients & 76 \\ Mean age (years) & 69.2 \(\pm\) 9.1 \\ Male gender & 54 (71.1\%) \\ Mean body mass index (kg/m\({}^{2}\)) & 28.1 \(\pm\) 4.6 \\ \hline
**Risk factors** & \\ Hypertension & 56 (73.7\%) \\ Dyslipidemia & 57 (75.0\%) \\ Diabetes mellitus & 28 (36.8\%) \\ Current smoker & 12 (15.8\%) \\ Family history of heart disease & 24 (31.6\%) \\ Peripheral vascular disease & 8 (10.5\%) \\ Previous myocardial infarction & 14 (18.4\%) \\ Previous PTCA & 26 (34.2\%) \\ Renal impairment & 2 (2.6\%) \\ \hline
**Indication for PCI procedure** & \\ Chronic coronary syndrome & 28 (36.8\%) \\ Unstable angina & 6 (7.9\%) \\ Non-ST elevation myocardial infarction & 5 (6.6\%) \\ Silent ischemia & 37 (48.7\%) \\ \hline
**Treated coronary artery** & \\ Number of lesions treated & 93 \\ Calcifications burden & \\ Mild & 29 (38.2\%) \\ Moderate & 35 (46.1\%) \\ Severe & 12 (15.8\%) \\ Lesion classification (AHA/ACC) & \\ A & 6 (6.5\%) \\ B1 & 62 (66.7\%) \\ B2 & 22 (23.7\%) \\ C & 3 (3.3\%) \\ Left anterior descending artery & 59 (63.4\%) \\ Left circumflex artery & 8 (8.6\%) \\ Right coronary artery & 25 (26.9\%) \\ Left main coronary artery & 1 (1.1\%) \\ \hline
**Stents** & \\ Number of stents implanted & 98 \\ Mean stent diameter (mm) & 3.16 \(\pm\) 0.46 \\ Mean stent length (mm) & 25 \(\pm\) 9 \\ Mean deployment pressure (atm) & 11 \(\pm\) 2 \\ Expected chart diameter (mm) & 3.25 \(\pm\) 0.47 \\ Post-dilation performed & 81 (82.7\%) \\ Non-compliant balloon & 71 (85.5\%) \\ Mean maximal post-dilatation balloon diameter (mm) & 3.57 \(\pm\) 0.54 \\ Mean maximal balloon inflation pressure (atm) & 18 \(\pm\) 3 \\ \hline \end{tabular}
\end{table} 
Table 2: Quantitative cohort baseline clinical, lesion, and stent characteristics. (Figure 1). A statistically significant difference (\(p<0.05\)) was also found between the mean total grade from observer 1 vs. observer 2 (4.10 \(\pm\) 1.86 vs. 3.76 \(\pm\) 1.58, respectively) for the evaluation of SE images with no statistically significant difference noted for the proximal and distal edge visualization grades (1.46 \(\pm\) 0.79 vs. 1.42 \(\pm\) 0.64 and 1.43 \(\pm\) 0.77 vs. 1.46 \(\pm\) 0.59 for observer 1 and 2, respectively). A Wilcoxon test demonstrated a statistically significant difference between the two observers (\(p<0.001\)) indicating that they assessed the visualization of struts differently. This demonstrates the variability in such a qualitative assessment of any angiographic parameter. The Kappa coefficients were calculated between the two observers (inter-observer Kappa) and between two different evaluations by the same observer (intra-observer Kappa). The evaluation system was simplified to a binary one. Inter-observer agreement between the two reviewers was observed (coefficient \(<\) 50% for the proximal stent edge with SB). The stent underexansion and calcification coefficients showed similar results (coefficient \(<\) 48%). The intra-observer Kappa coefficients showed low reproducibility with perhaps a better reproducibility for the SB. There was no significant difference between the two methods, SB or SE, according to the Wilcoxon test for each observer (Table 4). A final Kendall test demonstrated a significant difference between the two observers for the assessment of underexansion and calcifications (Figure 2). While the first reviewer found a correlation of \(\pm\)60%, the second one found \(\pm\)90% (Table 5).