Cardiac surgery as a stressor and the response of the vulnerable older adult.

In an aging population, recovery and restoration of function are critical to maintaining independence. Over the past 50years, there have been dramatic improvements made in cardiac surgery processes and outcomes that allow for procedures to be performed on an increasingly older population with the goal of improving function. Although improved function is possible, major surgical procedures are associated with substantial stress, which can severely impact outcomes. Past literature has identified that frail patients, who are vulnerable to the stress of surgery, are more likely to have postoperative major adverse cardiac and cerebrovascular events (OR 4.9, 95% confidence interval 1.6, 14.6). The objective of this manuscript is to examine preoperative frailty in biological, psychological, and social domains using cardiac surgery to induce stress. We systematically searched PubMed for keywords including "cardiac surgery, frailty, and aged" in addition to the biological, psychological, and social keywords. In the biological domain, we examine the association of physiological and physical vulnerabilities, as well as, the impact of comorbidities and inflammation on negative surgical outcomes. In the psychological domain, the impact of cognitive impairment, depression, and anxiety as vulnerabilities were examined. In the social domain, social structure, coping, disparities, and addiction as vulnerabilities are described. Importantly, there is substantial overlap in the domains of vulnerability. While frailty research has largely focused on discrete physical vulnerability criteria, a broader definition of frailty demonstrates that vulnerabilities in biological, psychological, and social domains can limit recovery after the stress of cardiac surgery. Identification of vulnerability in these domains can allow better understanding of the risks of cardiac surgery and tailoring of interventions to improve outcomes.