Acute Coronary Syndromes in the Young — The ISACS-TC Experience

Background: Although coronary heart disease (CHD) mainly occurs in patients over the age of 50, younger patients can be affected as well. Most studies have used an age cut-off of 45 years to define "young" patients with CHD or acute coronary syndrome (ACS). We used this definition to investigate clinical characteristics and outcomes of ACS young patients in a large international cohort. Methods: Between 2010 and 2016, 14931 ACS patients were enrolled in the ISACS-TC registry (ClinicalTrials.gov NCT01218776). Of these patients, 1182 (8%) were aged ≤45 years old (mean age 40.3 years, 15.8% female). The primary end-point was ST segment elevation myocardial infarction (STEMI) as index event and 30-day all-cause mortality. Percent diameter stenosis of 50% or less was defined as insignificant coronary disease. Results: STEMI is the most common clinical manifestation of ACS in the younger cases. Younger patients had a higher incidence of insignificant coronary artery disease and single vessel disease. Conversely, three-vessel disease was less common in the younger patients. Smoking was the most important risk factor in this population. Predictors of ACS in the young population included male sex (OR: 2.21), smoking habit (OR: 1.10), and higher BMI (OR: 1.04). Thirty-day unadjusted survival rates were 98.7% versus 93.1% for young and older patients respectively. After adjusting for baseline characteristics, medications at admission and reperfusion therapy, age ≤45 years old was a predictor of survival in men (OR 0.25, 95% CI 0.10-0.64), but not in women (OR 1.51, 95% CI 0.55-4.18). Moreover, younger women had worse outcomes than men of similar age (OR 6.84, 95% CI 2.23-20.97). Conclusion: ACS at a young age is characterized by less severe coronary disease and worse clinical presentation. Women have higher mortality than men. Factors underlying ACS in young patients and higher mortality rates in female sex warrant further investigation