Introduction: The Changing Face of the Cardiac ICU
For decades, the Cardiac Intensive Care Unit (CICU) was primarily defined by the management of elderly patients suffering from acute coronary syndromes and their sequelae. However, as the landscape of cardiovascular medicine evolves, so too does the demographic profile of the critically ill cardiac patient. While the aging population remains a cornerstone of CICU care, a distinct and increasingly visible subgroup has emerged: the young adult. Defined as individuals aged 18 to 39, these patients often present with different etiologies, higher clinical acuity, and unique psychosocial needs compared to their older counterparts.
Despite their presence, young adults have remained an under-explored population in critical care cardiology. Understanding their clinical trajectories is essential for optimizing resource allocation and tailoring therapeutic strategies. A recent study published in the European Heart Journal: Acute Cardiovascular Care, utilizing data from the Critical Care Cardiology Trials Network (CCCTN) registry, provides a comprehensive characterization of this demographic, offering vital insights into their presentations, treatments, and outcomes.
The CCCTN Registry: Study Design and Population
The study analyzed data from the CCCTN, a multicenter registry of advanced (Level 1) CICUs across North America. The researchers looked at consecutive adult admissions between 2018 and 2023, totaling 29,035 admissions. Within this cohort, 1,959 patients (6.7%) were identified as young adults (aged 18-39). This group was compared against the older cohort (aged 40 and above) to identify differences in demographics, admission diagnoses, disease severity, and hospital outcomes.
The use of a multicenter registry like the CCCTN is particularly valuable here, as it reflects contemporary practices in high-volume, specialized centers that are equipped to handle complex cases requiring advanced mechanical circulatory support (MCS) and multidisciplinary care.
Demographic Shifts: Diversity and Gender in Young CICU Patients
One of the most striking findings of the study was the demographic divergence between age groups. Young adults in the CICU were significantly more likely to be female (40.0% vs. 36.4%, p=0.001) and non-white (55.3% vs. 43.0%, p<0.001) than older patients. This highlight suggests that the burden of critical cardiovascular illness in the young disproportionately affects minority populations and women, potentially reflecting underlying socioeconomic disparities, differences in access to primary care, or genetic predispositions to conditions like peripartum cardiomyopathy or early-onset non-ischemic heart failure.
Interestingly, while traditional cardiovascular risk factors—such as hypertension, diabetes, and prior coronary artery disease—were less prevalent in the young adult group, the clinical severity at the time of admission was notably higher. This suggests that when young adults do require intensive care, it is often due to acute, severe physiological derangements rather than the gradual progression of chronic atherosclerotic disease.
Clinical Presentation: The Dominance of Heart Failure and High Acuity
The primary drivers of CICU admission differed significantly by age. While older adults were frequently admitted for acute coronary syndromes, heart failure was the leading admission diagnosis among young adults, accounting for 26.4% of cases compared to 19.5% in older adults (p<0.001).
More concerning was the acuity of these presentations. Young adults were more likely to present in extremis:
Cardiogenic Shock and Cardiac Arrest
Young adults had a higher prevalence of cardiogenic shock at admission (22.4% vs. 18.7%, p<0.001) and a higher incidence of cardiac arrest (12.7% vs. 10.6%, p=0.003). These findings underscore a clinical paradox: despite having fewer comorbidities and presumably greater physiological reserve, young patients in the CICU are often 'sicker' upon arrival than older patients.
Etiological Differences
In this younger cohort, the etiologies of heart failure and shock often lean toward non-ischemic causes, including myocarditis, drug-induced toxicities, and congenital heart disease. The rapid onset of these conditions may explain the high rates of shock and arrest compared to the more predictable, chronic progression seen in older ischemic patients.
Resource Utilization: Intensive Care for the Young
Given the higher acuity of their presentations, young adults required a more intensive level of care. The study found that utilization of critical care therapies was significantly higher in the 18-39 age group. Mechanical circulatory support (MCS) was used in 13.1% of young adult admissions compared to 11.4% of older adults.
The Role of ECMO
Perhaps the most notable difference in therapy was the type of MCS utilized. Extracorporeal membrane oxygenation (ECMO) comprised 29.3% of the MCS used in young adults, whereas it represented only 9.9% in the older cohort (p<0.001). The preference for ECMO in younger patients likely reflects its utility as a 'bridge'—either to recovery, to a long-term ventricular assist device (VAD), or to cardiac transplantation. Clinicians may be more aggressive with salvage therapies like ECMO in younger patients due to their potential for long-term survival and the absence of age-related contraindications.
Additionally, young adults had longer median CICU stays (2.7 days vs. 2.2 days), reflecting the complexity of their management and the time required to stabilize high-acuity conditions or wait for advanced surgical interventions.
Survival Outcomes: The Resilience of Youth
Despite the higher rates of shock, cardiac arrest, and the need for invasive support, young adults demonstrated significantly better survival outcomes. The study reported:
CICU and Hospital Mortality
CICU mortality was 6.5% for young adults versus 10.5% for older adults. Hospital mortality showed a similar trend, at 9.5% for the young versus 14.4% for the older cohort (p<0.001).
This 'survival advantage' is likely multi-factorial. First, the greater physiological reserve of younger patients allows them to tolerate severe metabolic and hemodynamic stress better than older patients with multiple comorbidities (e.g., renal failure, frailty, pulmonary disease). Second, the lower prevalence of multi-organ dysfunction prior to the acute event may lead to more successful weaning from mechanical support. Finally, the higher rates of ECMO and MCS utilization suggest that an aggressive 'full-court press' strategy in younger patients is often successful in achieving survival.
Expert Commentary: Interpreting the Data
The findings from the CCCTN registry provide a crucial wake-up call for critical care cardiologists. The high proportion of non-white and female patients in the young adult cohort highlights an urgent need for targeted public health interventions and a deeper investigation into the social determinants of health that drive early-onset heart failure.
From a clinical perspective, the data suggest that the CICU is no longer just a place for ‘heart attack’ management but has become a hub for advanced heart failure and shock management, particularly for the young. The reliance on ECMO in this group necessitates that these patients be managed in—or rapidly transferred to—high-level centers with the expertise to provide such advanced therapies.
However, the study also has limitations. As a registry of advanced CICUs, the data may not represent the presentations seen in smaller community hospitals. Furthermore, while short-term survival is excellent, the long-term morbidity and quality of life for young survivors of cardiogenic shock and ECMO remain areas that require further longitudinal study.
Conclusion
Young adults represent a clinically distinct and highly complex population within the modern CICU. They present with a higher burden of critical illness, including shock and arrest, necessitating intensive and expensive resources like ECMO. Yet, their potential for recovery is high, with significantly lower mortality rates than older patients. Recognizing the demographic trends—particularly the higher representation of women and minority groups—is the first step toward addressing the unique needs of this population. As the CICU continues to evolve, our management strategies must remain as dynamic as the patients we serve.
References
1. Isath A, Sharma T, Mahmood U, et al. Young Adults in the Cardiac Intensive Care Unit: Insights from the Critical Care Cardiology Trials Network Registry. Eur Heart J Acute Cardiovasc Care. 2025;zuaf161. doi:10.1093/ehjacc/zuaf161.
2. Katz JN, et al. Evolution of the Cardiac Intensive Care Unit: A Scientific Statement From the American Heart Association. Circulation. 2020;142(13):e185-e199.
3. Berg DD, et al. The Critical Care Cardiology Trials Network (CCCTN): A Multicenter Registry of Cardiac Intensive Care Units. J Am Coll Cardiol. 2019;73(24):3130-3132.
