Subcutaneous Defibrillator for Primary Prevention in Chronic Kidney Disease Stage 3–5: The Single‐Arm STEADIED Study
Tae‐Wan Chung, Tae‐Hoon Kim, Boyoung Joung, Seung‐Jung Park, Eue‐Keun Choi, Myung‐Hwan Bae, Jong Sung Park, Il‐Young Oh, Min‐Soo Cho, Jong‐Sung Park, Min‐Su Jung, Hyoung‐Seob Park, Youngjun Wi, Jongmin Hwang, Seongwook HanABSTRACT
Background
Prospective data on the subcutaneous implantable cardioverter‐defibrillator (S‐ICD) in chronic kidney disease (CKD) are lacking. We estimated the rate of appropriate ICD therapy with the S‐ICD in CKD stage 3–5 with left ventricular ejection fraction (LVEF) ≤ 35%.
Methods
In this single‐arm exploratory study, adults with CKD stage 3–5 and a guideline‐based primary‐prevention indication received an EMBLEM MRI S‐ICD at eight Korean centers. The primary endpoint, appropriate ICD therapy, was hypothesized at 18% versus a historical rate of 7.8% ( α = 0.05, 80% power, planned N = 77; exact binomial test).
Results
The study was terminated early after 39 patients (51% of target; achieved power ≈61%). Mean LVEF was 27.8% and median eGFR 11.7 mL/min/1.73 m 2 ; 71.8% had CKD stage 5 and 69.2% were on hemodialysis. Over a median follow‐up of 361 days, appropriate ICD therapy occurred in 2 patients (5.1%; 95% CI, 1.4–16.9), significantly below the hypothesized 18% ( p = 0.036). Inappropriate shocks occurred in 5 patients (12.8%; 95% CI, 5.6–26.7; 8 shocks), a proportion 2.5 times that of appropriate therapy, from external electromagnetic interference (2 patients), multiple counting after automatic SMART Pass deactivation (2), and supraventricular misclassification (1). Three deaths (7.7%) occurred, none device‐related or documented as arrhythmic (one undetermined); all hospitalizations were for heart failure, and no systemic device infection occurred.
Conclusions
In this exploratory single‐arm study, appropriate ICD therapy was infrequent and exceeded by inappropriate shocks, while non‐arrhythmic competing mortality dominated the clinical course. These hypothesis‐generating findings support cautious patient selection, verification of filter status during follow‐up, and larger comparative studies.
Trial Registration
Clinical Research Information Service (CRIS), Republic of Korea; identifier KCT0005596