From Percutaneous Coronary Intervention to Heart Failure with Reduced Ejection Fraction: A Case Report Highlighting the Impact of IneffectiveSecondary Prevention

Background: Coronary artery disease (CAD) is a leading cause of mortality worldwide, with long-term outcomes heavily dependent on secondary prevention. Poor adherence to guideline-directed therapy and unhealthy dietary practices significantly increase the risk of recurrent ischemic events, restenosis, and heart failure. Long-term success after percutaneous coronary intervention depends heavily on continuous adherence to medical therapy and lifestyle modification. Case Presentation: This study reports the case of a 63-year-old Indian male with diabetes and hypertension who previously underwent percutaneous coronary intervention in 2014 for myocardial infarction. In 2018, the patient stopped taking both dual antiplatelet therapy and statins and changed to a completely open dietary plan with a large amount of saturated fat in his diet. By 2025, he had unstable angina, which was ultimately diagnosed as a non–ST-elevation myocardial infarction. During coronary angiography, he was found to have significant triple-vessel disease, including in-stent restenosis and a left ventricular ejection fraction of 25% to 35%. As a result, after revascularization, he was treated with a combination of dual antiplatelet therapy, a high-intensity statin, sacubitril/valsartan, and a sodium-glucose cotransporter-2 Inhibitor. While initially all medications were successfully managed, the patient was ultimately found to have irreversible myocardial dysfunction due to prolonged nonadherence with proper management and lifestyle modifications. Conclusions: This case highlights the potential long-term consequences of discontinuing prescribed cardiac medications and neglecting dietary advice after revascularization. Although multiple factors such as progression of diabetes, metabolic disturbances, and recurrent ischemia may contribute to ventricular dysfunction, prolonged interruption of guideline-directed therapy and periodic assessment of therapeutic targets likely played an important role in the progression of coronary disease and development of heart failure.