Table 3.
Study endpoints
| Endpoint | Time frame (mo) | Description | Expected value | Performance goal | Statistical test | α level (%) | Power level (%) | Subjects | Assumed attrition (%) | Subjects with assumed attrition | Lower confidence limit |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Safety endpoint 1 | 6 | Major mCRM system- and procedure-related complication–free rate | 93% | 86% | K-M | Overall: 2.5 | 90 | — | 25 | Interim: 179 | — |
| Interim: 1.2 | Interim: 134 | 98.8% 1-sided, pointwise | |||||||||
| Final: 1.9 | Final: 223 | Final:298 | 98.1% 1-sided, pointwise | ||||||||
| Safety endpoint 2 | 12 | Major mCRM system- and procedure-related complication–free rate | 92% | 81% | K-M | 2.5 | 90 | 112 | 30 | 160 | 97.5% 1-sided, pointwise |
| 99.8 | 210 | 300 | |||||||||
| Primary effectiveness 1 | 6 | Communication Success between S-ICD and LP | 95% | 88% | Repeated-measures logistic regression | 2.5 | 80 | 152 tests/38 subjects | 30 | 220 tests/55 subjects | 97.5% 1-sided, pointwise |
| Primary effectiveness 2 | 6 | % subjects with adequate pacing capture threshold ≤2 V @ 0.4 ms | 95% | 80% | Binomial | 2.5 | 90 | 57 | 30 | 82 | Binomial, 2.5% 1-sided, exact |
| Secondary safety | 24 | All-cause survival | 92.7% | 85% | K-M | 2.5 | 80 | 123 | 40 | 275 | 5% 1-sided, pointwise |
| Secondary effectiveness | 3 | LP rate response function | 0.65 ≤ mean MCR slope ≤ 1.35 | 0.85 ≤ mean MCR slope ≤ 1.15 | Kay-Wilkoff model22,23 | 2.5 | 90 | 35 | 40% | 59 | 95%, lower limit |
K-M = Kaplan-Meier; LP = leadless pacemaker; MCR = metabolic-chronotropic relation.