Aim <p>Cardiovascular disease poses a significant health and economic challenge in Europe, yet the adoption of novel cost-effective treatments like icosapent ethyl remains limited. This study aims to estimate the absolute and relative value of eliminating suboptimal implementation of icosapent ethyl in Sweden.</p> Methods <p>This study estimates the effects of optimal and actual implementation of icosapent ethyl in Sweden with a five-year perspective by combining available cost-effectiveness evidence with epidemiology data from the Swedeheart registry and Swedish health authorities. The implementation analysis is based on the expected value of perfect implementation framework which estimates the value of increasing implementation from the current level of prescriptions up to an optimal level, where 80% of patients with indication for icosapent ethyl receives it.</p> Findings and interpretation <p>The results provide an upper limit of the value that could be gained by improving implementation of icosapent ethyl in five years in Sweden. Optimal implementation of icosapent ethyl in Sweden over five years could prevent 1,228 cardiovascular events, including 99 deaths, while generating a health gain of 3,538 QALYs and net value of implementation of 497 QALYs. Regional differences and delays in implementation play a major role in the suboptimal uptake of care. Enhancing implementation strategies could lead to additional gains in QALYs and significantly reduce CV events and healthcare costs.</p> Conclusion <p>There is significant health, QALY and monetary gains in ensuring improved implementation of icosapent ethyl in Sweden. There is a need for tailored interventions to address factors influencing prescribing practices. However, challenges remain with a lack of clear national or local guidelines. By decreasing the large regional variations, one could enhance patient outcomes.</p>