172 | Chapter 8 Figure 3. Ventricular arrhythmia (VA) free survival in presence of abnormal RV function measured by deformation imaging Panel A. When dividing RV free wall longitudinal strain (RVFWLS) into three groups, a clear difference in VA-free survival was seen. Panel B. A normal RV deformation pattern (type I) was associated with excellent negative predictive value (0.96, 95% CI 0.87 – 0.99). Especially the most abnormal type 3 deformation was associated with worse outcome. Deformation imaging in personalized risk prediction Discriminative value of the current ARVC risk calculator model was good in this cohort with a C-statistic of 0.78 (95% CI 0.71 – 0.86), consistent with prior results.(4) The strongest predictors of VA among the deformation parameters were RVFWLS, abnormal RV deformation pattern and LV GLS. Incremental predictive value was found when adding RVFWLS or abnormal RV deformation pattern to the risk calculator. Adding LV GLS, however, did not seem to improve prediction of VA (Table 3). The resulting adjusted HR was 1.07 ([95% CI 1.02 – 1.11], p = 0.004) per % worsening of RVFWLS and 4.45 ([95% CI 1.07 – 18.57], p = 0.040) in case of an abnormal regional deformation pattern. Optimism-corrected C-statistics were higher when RVFWLS or RV deformation pattern was added to the model (in both cases 0.82 [95% CI 0.75 – 0.88]). Also, both RV parameters reduced the model AIC by >2, which was not the case for LV GLS. The intermediate arrhythmic risk subgroup (5-year VA risk 5 – 25% as per the ARVC risk calculator) consisted of 73 patients. In this subgroup, no events occurred in the 28 patients who had normal regional RV deformation patterns. In the 7 intermediate risk patients who did experience VA during follow-up we observed abnormal regional RV deformation patterns, resulting in a specificity of 0.41 (95% CI 0.31 – 0.57) and positive predictive value of 0.16 (95% CI 0.14 – 0.19).
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