The impact of implantable cardioverter-defibrillator on long-term prognosis of successfully resuscitated patients with vasospastic angina after out-of-hospital cardiac arrest

Background Severe coronary artery vasospasm can provoke malignant ventricular arrhythmias and represents an important cause of out-of-hospital cardiac arrest (OHCA). Several studies worldwide have reported that vasospastic angina (VSA) accounts for approximately 2–11% of OHCA cases. However, the clinical benefit of implantable cardioverter-defibrillator (ICD) implantation for secondary prevention in this population has not been clearly established. Methods Between January 2015 and December 2023, 3,578 patients with OHCA were transferred to our institution. Of these, 318 achieved return of spontaneous circulation and underwent coronary angiography (CAG) to determine the underlying cause. Among them, 28 patients were diagnosed with VSA. Inclusion criteria were as follows: a positive acetylcholine provocation test; severe stenosis or occlusion on initial CAG that completely resolved with vasodilator therapy alone; or transient ischemic electrocardiographic changes accompanied by anginal symptoms without explanatory coronary lesions on CAG. One-year adverse events—defined as all-cause mortality, acute coronary syndrome, stroke, and ventricular arrhythmia (including ICD therapy)—were compared. Neurological status was evaluated using the Cerebral Performance Category (CPC) scale, with favorable neurological outcome defined as CPC 1–2. Results VSA was identified as the cause of OHCA in 28 patients (0.8%). The initial cardiac rhythm was shockable in 83% of cases. Twenty-four patients (85.7%) survived to hospital discharge, and 22 patients (78.6%) achieved favorable neurological outcomes. Of the 25 patients followed for 1 year after discharge, 20 (80%) survived with favorable neurological status (figure). All 24 survivors received vasospasm-preventive therapy, including calcium channel blockers, nitrates, and/or nicorandil. ICD implantation was performed in 14 patients (58.3%). During follow-up, appropriate ICD therapy occurred in 1 of 14 patients (7.1%), while inappropriate therapy occurred in 2 of 14 patients (14.3%). No significant differences were observed in the incidence of adverse events between the two groups. Likewise, there were no significant differences in 1-year survival or favorable neurological outcomes (13/14 [92.6%] vs. 7/7 [100%], P = 1.000). One patient with poor medication adherence experienced recurrent OHCA within 1 year despite ICD implantation. Conclusions No statistically significant differences in adverse events were observed between patients with and without ICD implantation. The occurrence of recurrent OHCA in a patient with poor medication adherence despite ICD therapy highlights that device therapy cannot replace optimal medical management. Routine ICD implantation for secondary prevention in patients with VSA-related OHCA may not be warranted; instead, management should be individualized, with strict adherence to optimal vasodilator therapy.