S-ICD System IDE Clinical Study

Prospective, Single-Arm Comparison to Objective Performance Criteria

Pre-market Investigational Device Exemption (IDE)

Background

The implantable cardioverter-defibrillator (ICD) has been shown to reduce total mortality up to 54% and arrhythmic mortality 50% to 70% in randomized, multi-center studies.1-4

Complications associated with the ICD procedure and system may diminish the mortality benefit.5-8

The subcutaneous ICD (S-ICD™) was developed as an alternative system. The S-ICD is a completely subcutaneous system that does not require leads in the heart, leaving the vasculature untouched.

Study Design

Objective:

  • Evaluate safety and effectiveness of the S-ICD System in the treatment of life-threatening ventricular arrhythmias


Design:

  • Prospective, multicenter, single-arm clinical study conducted in the U.S., Europe, and New Zealand.
  • Primary end-point comparison to objective performance criteria pre-defined by FDA
  • Enrollment began Jan 2010 and concluded May 2011
  • Follow up: > 1 year for first 100 patients; > 6 month for all patients

IDE Study Design IDE Study Design


Inclusion

  • Age ≥ 18 years
  • Met guidelines for ICD implantation3 or replacement of an existing ICD system
  • An appropriate pre-operative ECG


Key Exclusion Criteria

  • Prior VT reliably terminated with anti-tachycardia pacing
  • Existing epicardial patches or subcutaneous array 
  • Unipolar pacemakers
  • Severe renal dysfunction (GFR ≤ 29)


Definition of Complications

  • Type I: caused by the S-ICD System
  • Type II: caused by the S-ICD System user’s manual or labeling of the S-ICD System
  • Type III: not caused by the S-ICD System but would not have occurred in the absence of the implanted S-ICD System

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Demographics

Attribute

Statistic/Category

N=321

n

%

Co-morbidities
History

Congestive Heart Failure

197

61

Hypertension

187

58

Myocardial Infarction

133

41

Diabetes

90

28

Atrial Fibrillation

49

15

Valve Disease

42

13

COPD

27

8

Stroke

18

6

Cardiac Surgical
History

Percutaneous Revascularization

92

29

CABG

48

15

TV-ICD

43

13

Valve Surgery

18

6

Pacemaker

4

1

Patient Distribution Similar to NCDR Registry

Patient Distribution Similar to NCDR Registry Patient Distribution Similar to NCDR Registry
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Trial Results

Summary of key results

Effectiveness Endpoints Met

  • 100% acute induced VF conversion rate
       (75 patient sub-study tested at > 150 days)
  • 100% chronic induced VF conversion rate
  • 95% of events treated in < 21 sec
  • Mean time to therapy for all inductions was 14.6±2.9 seconds


Safety Endpoints Met

  • 99% Free from Type I complications
  • 92.1% Free from Type I-III complications
  • No deaths associated with S-ICD 

Both endpoints met even under worst case sensitivity analysis

Induced VT/VF Conversion Results

Evaluable Results Conversion Rate (%) 95% Lower Bound (%)
Successful Failure
304 0 100.0 98.8

In 16 patients testing results were deemed nonevaluable and 1 patient did not undergo any testing because of persistent left ventricular thrombus. Ten of the 16 nonevaluable patients, including 1 patient not tested because of left ventricular thrombus, remained with the device and were followed up for the safety end point, whereas 7 patients were not implanted with the S-ICD System and were withdrawn from the study.

When all 17 excluded tests were classified as failures, the acute VF conversion rate had a success rate of 94.7% (lower 95% CI 91.7%) which exceeds the performance goal of 88%.


Spontaneous VF/VT Episodes

  • 12 month first appropriate shock incidence = 6.2%
  • 119 events in 21 patients
  • 37 of 38 (97.4%) converted with with 1 or more shocks. The single episode not converted by the S-ICD System was an episode of monomorphic VT that terminated spontaneously while the device was charging to deliver a second shock.
  • 92% first shock conversion efficacy

Spontaneous VT/VF Episodes

Evaluation

Total

Discrete

Storm

Episodes

119

38

81 (4 events)

Patients

21*

21

2

* Row entries do not sum because 2 pts experienced both discrete and storm episodes (mean follow up = 11 months)


Therapy Appropriately Withheld

  • Algorithm prevents therapy for VT/VF rhythms that spontaneously terminate prior to discharge.
  • Therapy was appropriately withheld in 25 patients with 32 MVT episodes that met criteria to charge.
  • No reports of syncope

Spontaneously Terminated Episodes of MVT = 33 Spontaneously Terminated Episodes of MVT = 33


Inappropriate Therapy

  • 41 patients experienced shocks due to non-VT/VF events
  • Dual zone programming reduced inappropriate shocks
  • No patients experienced a shock due to discrimination error in the Conditional Shock (dual) zone

Inappropriate Therapy Inappropriate Therapy


Complications

  • 4.4% perioperative complication rate
  • 4 explant for infection (first 1/3 of pts)
  • No arrhythmic deaths
  • No endocarditis or systemic blood stream infections

Complication-Free Rate Complication-Free Rate


Few Infections Led to Explant

  • All infections requiring explant occurred early in the study before investigators meeting

Study-Wide Learning on Surgical Prep Study-Wide Learning on Surgical Prep
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