Ageism is the practice of stereotyping, prejudice, and/or discrimination against individuals or groups based on their age. It includes any attitude, action, or institutional structure that discriminates against a person or group of people exclusively because of their age [8]. Given that age is only a weak predictor of outcomes in critically ill patients, the decision to treat based only on the patient’s age is unacceptable [5]. Ageism is a widely spread attitude that has a detrimental effect on health [9, 10, 11]. There are three of components of ageism that can affect health: (1) discrimination when receiving certain treatments (unjustified do-not-resuscitate-orders [12], administration of cheaper treatments [13], lower quality treatments [14] …); (2) negative stereotyping; and (3) negative self-perception of aging itself. These components influence psychological and behavioral mechanisms. Ageism might be structural (promoted by institutions), and individual (due to assimilated negative beliefs about age) [9]. In a recent meta-analysis [9] both structural and individual ageism influenced health through different domains, with a worse health outcome involving ageism in 96% of the analyzed studies. Structural attitudes include exclusion from clinical trials and research studies, denial of medical assistance or treatment, and non-medical attitudes such as devaluation of life and lack of employment opportunities. Surprisingly, the detrimental effect of ageism on health is even stronger than the well-known negative effect of racism [15].

Ageist attitudes, especially in medicine, might be related to the misconception of elderly people as vulnerable individuals. This misconception is derived from negative stereotypes of advanced age in terms of helplessness and dependence. Vulnerability [16] is defined as increased susceptibility to damage. Advanced age is not a synonym of vulnerability. Most elderly persons have reached sufficient maturity and passed certain stages of life that would allow them to increase their economic relevance, cultural influence, and political representation. However, aging increases the probability of suffering injury due to low reserve and frailty. Nevertheless, the elderly maintain development potential and can acquire capacities to fight against certain aggressions, so chronological age should not be considered the only vulnerability criterion.

The different components of ageism found in the ACS healthcare process and their influence on major outcomes are shown in Fig. 1.

Fig. 1.

Components of ageism and its influence on outcomes in acute coronary syndrome. Ageism is well related to the concept of vulnerability, and it has three components that can be noted in the management of acute coronary syndrome. The elderly may receive lower quality treatment due to its price; the preferences and goals of the patient may not be considered, and a negative self-perception of aging may appear. These may lead to mental disorders and unhealthy lifestyles with an increased likelihood of a new acute coronary syndrome.

The incidence of ACS will progressively increase with aging of the population, and will produce an increase in the number of elderly patients admitted with ACS. Thus, it is very important to consider the correct decision-making processes to follow for this specific population [17]. Ageist attitudes may arise at different points in the diagnosis and treatment of ACS, either when deciding on antithrombotic medical treatment, the indication for percutaneous revascularization, or the site of admission (cardiology ward versus acute care units). Table 1 details ageist attitudes in the healthcare process involving patients with ACS.

Current guidelines recommend coronary angiography and, if indicated, percutaneous coronary intervention (PCI) [18, 19] in patients with ST-segment-elevation myocardial infarction (STEMI) and non-ST-segment elevation of myocardial infarction (NSTEMI) irrespective of age. However, in the case of NSTEMI, the elderly population is underrepresented in clinical trials [20], even more so in patients with advanced age and geriatric syndromes [21] and comorbidities. Thus, PCI in this population could be controversial and requires careful individual assessment. The lack of evidence and some ageist attitudes may explain why the elderly are less likely to be treated with PCI than younger patients, even when confounding factors are considered [22]. The cost and staff required for PCI, and its invasive nature, could be some of the reasons for this discrimination. The elderly have a higher risk of adverse events than middle-aged and younger patients, and they are less likely to receive optimal medical treatment and to undergo coronary angiography and PCI [23].

In the elderly, it is essential to consider the goals of the treatment [24]. ACS at an advanced age is a high-risk condition due to the high risk of adverse events, procedural complications, and mortality [25]. However, comparing the results of a study between age groups solely based on mortality might lead to ageist attitudes. As age is a non-modifiable risk factor, the question is whether the elderly benefit from a certain treatment, not whether the benefit is higher or lower than in younger patients. Therefore, the correct attitude would be to compare different treatments in similar age groups to avoid ageist attitudes [26]. In addition, we should reflect on all the outcomes of the studies, such as quality of life, since mortality alone might not be the most important objective in this age group.

Some randomized clinical trials compared invasive versus a conservative strategy in elderly patients with non-ST-segment-elevation ACS. The After Eighty Study [27], which included 457 patients aged 80 years or older, suggested that an invasive strategy was superior to conservative management, but a large number of patients were excluded due to logistical reasons; so that there may have been an element of selection bias. In addition, the benefit decreased with age, without a clear benefit in nonagenarians. The Italian Elderly ACS trial [28], which included 313 patients aged 75 years or older, failed to show such a benefit. However, NSTEMI patients managed with an invasive strategy had a 57% reduction in the primary endpoint. The Revascularization or Medical Therapy in Elderly Patients With Acute Anginal Syndromes (RINCAL) trial [29], which included 251 patients $\ge$80 years, was terminated prematurely due to slow recruitment. The early invasive intervention group showed less reinfarction but there was no improvement in survival. In addition, a recent meta-analysis showed that an invasive strategy was associated with a reduction in myocardial infarction [30]. In summary, these studies showed that we should not preclude elderly patients from an invasive strategy based only on chronological age. ACS in the elderly presents with more complex coronary anatomy and a higher risk of associated complications, especially geriatric syndromes (comorbidities, polypharmacy, physical frailty, and cognitive impairment) so that an individual assessment with a patient-centered decision making process is mandatory [31, 32]. This should include an invasive approach and revascularization in patients with geriatric syndromes, since a positive influence on outcomes can be achieved [33, 34, 35, 36, 37, 38, 39]. The MOSCA trial [40] included 106 patients aged 70 years or older with comorbidities. The results showed that an invasive strategy in older patients with at least two comorbidities did not improve long-term events, although it did decrease mortality at 3 months. The Invasive Versus Conservative Strategy in Frail Patients With NSTEMI (MOSCA-FRAIL) is an ongoing trial involving patients aged 70 years or older with frailty criteria [41]. When it is published, it will help to clarify the appropriate management in frail elderly patients with ACS [41]. However, the previous results from LONGEVO suggested that the benefit in the frail elderly population could be inferior [42].

One reason to avoid an invasive approach or revascularization would be the patient preferences. Although few studies analyzed this issue, most data suggest that the elderly usually accept invasive management when properly explained [26]. In a recent study [43] individual knowledge, preferences, and priorities in invasive cardiac care were noted in 628 patients according to age (75 years vs. $\ge$75 years). Older patients had less knowledge of invasive care and were less willing to consider cardiac catheterization or PCI. In addition, maintaining cognitive function was a top priority for this population (29% of patients $\ge$85 years prioritized symptom relief, and losing mental capacity was the top concern). A previous qualitative study including 38 patients [44] showed that elderly patients were likely to follow their cardiologists’ recommendations. Although the elderly usually preferred drug treatment to invasive management, they even accepted surgery when needed. Interestingly, this study showed that elderly patients felt that age was a barrier to access a cardiologist consultation, a clear example of ageism. Community-dwelling adults are aware of the potential harms or complications [45]. Stroke is the least acceptable outcome followed by major myocardial infarction, cognitive dysfunction, renal failure, death, prolonged ventilator support, heart failure, angina, sternal wound infection, major bleeding, re-operation, prolonged recovery, cardiac readmission, minor myocardial infarction, and PCI. Of note, clinical decisions were more sensitive to the potential risk of harm than to the potential benefit.

An important issue in older patients undergoing coronary angiography and PCI is informed consent, a materialization of the principle of autonomy. Informed consent is a right of all patients and is regulated by different legislations. It has 7 components: (1) Competence: the ability to understand and decide; (2) Voluntariness: absence of controlling influences among which are coercion, persuasion, and manipulation; (3) Provide and explain the information; (4) Recommend a plan; (5) Understanding the information and the plan; (6) Decision; and (7) Authorization [5]. In some countries, informed consent forms used in cardiology procedures have ethical deficiencies [46]. In older patients, the approach and management may be different resulting in ethical challenges that should be solved using clear communication and eliminating potential obstacles. The elderly should be considered capable of handling their healthcare and making their own decisions, age does not impair the ability to decide. However, information should be individualized, and we should confirm patient comprehension [47, 48] since an impaired understanding could be present [49]. Thus, the informed consent should be adapted to patient understanding and linked to the level of education, and personality. Potential communication barriers such as sensorial deficits, cognitive impairment, and other conditions should be considered and an attempt should be made to overcome them by providing aids [47, 48]. Communication with a family member may reduce anxiety and facilitate the process. More concise forms with fewer technicalities and larger print would be especially helpful for the elderly population. Focusing on the whole decision-making process, effective communication, and a proportionate and individualized approach to consent could improve the experience of many cardiology patients [50]. However, it is important to consider that in life-threatening conditions such as STEMI; time to treatment is critically important, and delaying it due to informed consent may lead to shock and death. In this scenario, clinicians must make a quick and individualized decision and informed consent may be problematic.

Some recommendations on professionalism and ethics have been recently published by the American Heart Association and the American College of Cardiology [51] and should be considered when treating elderly people with ACS and deciding about invasive cardiac care. The concepts of “patient-centered care” and “shared decision process” are of greater interest in this field. Patient-centered care should be “respectful care that responds to the individual preferences of the patient, their needs and values, ensuring that the patient guides all clinical decisions” [52]. The shared decision process is a “structured process that involves the patient and the doctor to generate decisions based on the best evidence and patient preferences” [53]. Signing the informed consent is not enough, we should consider other recommendations to adequately guarantee respect for patients’ autonomy: (1) Medical care must be aimed at optimizing results and supporting the values ​​that are most important to the individual. This recommendation is simple when the patient’s wishes coincide with the best medical decision. On the other hand, it requires further study, ensuring that the patient understands the situation, in the event of a disagreement. It is also important to explore the cultural values ​​of the patient as imposing patient-centered care in certain cultures may not help and may even be harmful. (2) Clinicians must obtain and document the preferences and values ​​important to the patient, including the goals of treatment. It is important to document the preferences in the medical record so that other team members are aware of them. Also, it is important to develop communication skills to engage in this type of conversation with the patient. (3) The structured shared decision process should be reserved for decisions with significant benefits within reasonable options. (4) The tools to support the formal shared decision process should be designed by a multidisciplinary team, which should include clinicians and patients. (5) Payers and health systems should support policies and infrastructures that facilitate patient-centered care, including the shared decision process when appropriate. The main limitations to implementing this care amongst health care professionals are the lack of time, space, and skills to carry it out, so it must be considered within their work and their remuneration.

Talking to patients about their goals and preferences is essential. In this sense, it may be important to discuss with the patient if he or she wants to live longer or to live better. There is a broad belief that older people prefer the quality of life over the length of life. However, the published results are heterogeneous, and some studies reported the desire of older people to live longer even with poor health [54]. Moreover, families and healthcare providers tend to underestimate these patients’ desires for extending life [55]. When discussing the quality of life, we should be very cautious and avoid personal preferences or the patient’s social worth. It is difficult to state criteria of quality of life with sufficient precision, but some strategies could be considered. For instance, intellectual disability is usually not relevant in determining if the treatment or procedure is in the patient’s best interest. Also, and especially for proxies, we should avoid confusing the quality of life for the patients with the value of the patient’s life for others [5]. In this sense is important to be cautious to prevent moving to involuntary euthanasia for unconscious or incompetent, non-dying patients, based on the arbitrary and inappropriate quality of life judgments (among them elderly patients) [56]. Quality, results, patient experience, and the reduction of unnecessary tests and procedures are the responsibility of the clinician and should be a high priority [51].

The optimization of medical treatment in ACS could also have ethical implications. In the acute phase of ACS, anti-platelets and anticoagulants are needed [18, 19]. However, as previously seen, elderly patients are usually excluded from clinical trials [36]. In this population, clinicians should carefully evaluate bleeding risk [36], comprehensive geriatric assessment, and comorbidities. This assessment should guide the decision regarding the type of P2Y${}_{12}$ inhibitor, dose, time, and duration (but not the price of the drug). Clopidogrel is the most commonly used anti-platelet agent among the elderly population [57], due to the results of the Study of Platelet Inhibition and Patient Outcomes (PLATO) [58] and in the Trial to Assess Improvement in Therapeutic Outcomes by Optimizing Platelet Inhibition With Prasugrel–Thrombolysis In Myocardial Infarction 38 (TRITON-TIMI 38) [59], due to the increased risk of fatal and intracranial bleeding in this population with prasugrel. In addition, there is a loss of benefit in older patients with prasugrel [60]. However, conflicting results regarding the optimal antithrombotic therapy in the elderly are reported [61, 62, 63]. A recently published meta-analysis showed that potent oral P2Y${}_{12}$ inhibitors in elderly patients with ACS reduced the risk of cardiovascular mortality with an increased risk of bleeding events [64]. Secondary prevention should also be considered after discharge.

In the healthcare process, we could also commit ageism when deciding the place of admission (cardiology ward vs. acute care units). Older patients should receive optimal healthcare assistance and should be admitted to an acute care unit if needed. The LONGEVO-SCA registry [65] analyzed 80-year and older patients admitted due to NSTEMI. Almost 30% of patients were admitted to intensive cardiac care units. Those patients were younger, had acute heart failure or poorer left ventricular ejection fraction, were troponin positive, and had higher punctuation in the ischemic risk scores. Also, they were less frail, had a lower prevalence of other geriatric syndromes, and had more frequently undergone a previous PCI. Those patients with a high risk and higher proportion of invasive treatment had the same clinical outcomes at 6 months as those admitted to the cardiology ward. The authors considered that this might be due to an adequate selection of patients, as those with higher risk had the same prognosis after being admitted to the acute care unit than patients with lower risk admitted to the cardiology ward. A French observational study [66] compared 311 octogenarians and 92 nonagenarians admitted to an intensive care unit for ACS. 5-year mortality was higher for nonagenarians, but no significant difference was found for 5-year cardiovascular mortality. Nonagenarians were less frequently treated with ticagrelor than octogenarians. Older age was related to all-cause mortality (as expected due to the life expectancy at their age) but was not a risk factor for cardiovascular mortality. Although evidence is scarce, chronological age should not be the reason for not admitting patients to acute care units [67, 68, 69, 70, 71, 72, 73, 74, 75]. An increasing number of elderly patients are being admitted to intensive care units [76]. The clinical decisions in these units should be based on shared decision-making considering patients’ preferences. We should also use a time-limited trial, which means all appropriate intensive care is used and the patient’s progress is carefully evaluated to assess if the “maximum” care is continued whether we should consider withdrawing the treatment [76].

However, sometimes there is a need to prioritize patients (as the COVID-19 pandemic has shown) or resources are scarce, and we should decide the treatment for different patients (of different ages) at the same time. In this scenario, we should consider the principle of justice, including social justice, as we will discuss in the next section.