The need for a patient to consult a cardiologist can be exemplified by the case a 65-year-old man who recently suffered an anterior wall myocardial infarction (MI) and who has been participating in cardiac rehabilitation, who presents with feelings of overwhelming depression and hopelessness. On three occasions since his hospitalization he has been evaluated in the local emergency department (ED) for recurrent chest symptoms. Each time his evaluations have been suggestive of non-cardiac causes for his symptoms and he has been advised to continue with his recommended medications with follow-up through his primary care provider (PCP). After these processes, it is time for the cardiologist to identify and treat the cause of his current distress.
While this case is somewhat extreme and unusual, it is not uncommon. It typifies an unusual dilemma in current cardiovascular (CV) healthcare—coronary artery disease (CAD) risk is associated with certain psychosocial factors, such as depression, yet treatments that effectively treat both psychosocial and CAD outcomes have been somewhat elusive. Results of recent clinical research have strengthened the understanding and management of the links between psychosocial and CV health, and have moved the field of behavioral cardiology steadily closer into the mainstream of current clinical cardiology.1,2
Behavioral cardiology is the study and application of psychosocial factors in the assessment and reduction of CAD risk. It is an important field for a number of reasons, including:
- adverse psychosocial factors are common in persons with CAD,3 with up to 50% of survivors of MI having evidence of significant anxiety and/or depressive disorders;4
- the presence of adverse psychosocial factors can significantly worsen CAD risk and prognosis;5-12 and
- psychosocial health status is generally responsive to behavioral and pharmacologic therapies.13,16
Behavioral cardiology is a complex field, as with many areas within behavioral medicine, and is one that hinges largely on the ability of non-behavioralists (generally cardiologists) to identify affected patients and to initiate the early steps in their psychosocial care. CV clinicians are in an important position to identify and help individuals with co-existing CAD and psychosocial distress because they are often among the first to see patients during and after CAD events (MI and coronary artery bypass surgery, etc.)—a time when adverse psychosocial factors may become more visible and when patients are often more open to therapeutic recommendations.
Behavioral and Psychosocial Factors and CAD Risk
Certain behavioral lifestyle factors, such as cigarette smoking, dietary intake, and physical activity, have been strongly linked to risk of CAD events and are common targets for therapeutic lifestyle change recommendations. These and other traditional CAD risk factors, such as family history of CAD and diabetes, are thought to explain up to 70% to 80% of CAD risk.17,18 Other factors, including various psychosocial and novel biologic factors, may help explain the remaining 20% to 30% of CAD risk variability.
Psychosocial factors are generally not included in multivariate predictive models of CAD risk prediction, such as those from the Framingham Heart Study, despite the fact that the strength of their association with CAD is similar to the risk factors included in CAD risk prediction equations—hypertension, smoking, diabetes, and hyperlipidemia.19,20
Psychosocial factors associated with CAD risk include some with negative and others with positive relationships to CAD (see Table 1). Psychosocial factors that have a negative influence on CAD risk include depression, anxiety, anger, hostility, and chronic stressors such as social isolation, low socioeconomic status, and chronic strain from difficult interpersonal relationships and/or responsibilities (occupational and caregiver roles, for example).1,5-12 Depression has been identified for many years as perhaps the strongest negative psychosocial risk factor for CAD risk,8 increasing the risk of morbidity and mortality by more than two-fold in people with existing CAD.21
Negative psychosocial factors are thought to directly affect CAD risk through a variety of pathophysiologic mechanisms, including alterations in autonomic nervous system activity and heart rate variability, blood pressure reactivity, endothelial reactivity, inflammation, coagulation factors, arrhythmias, and atherosclerotic plaque stability.1,5-12,22-24 Indirectly, psychosocial factors may also affect CAD risk by exerting a negative influence on adherence to healthy behavioral lifestyle habits (healthy nutrition habits, regular exercise, and tobacco avoidance, for instance).1
A number of positive psychosocial factors are associated with reduced CAD risk, including optimism, sense of humor, forgiveness, social support, religious faith, vitality, forgiveness, gratitude, altruistic behavior, emotional flexibility, and coping flexibility.25-30 The risk of CAD associated with these positive psychosocial factors is reduced by up to half of that observed in people without these positive factors.9
Positive factors, such as optimism, are thought to exert beneficial effects on CAD risk through physiologic mechanisms that generally run opposite those associated with the previously mentioned negative psychosocial factors. For instance, positive psychosocial factors have been associated with beneficial effects on autonomic nervous reactivity,25,26,31 and immune system protection against infection.32 They might also help to reduce CAD risk by reinforcing a person's desire and ability to adhere to healthy lifestyle habits and to preventive medications, such as anti-platelet, anti-hypertension, and lipid-lowering drugs.1,33
Psychosocial Factors and CAD Risk Reduction
The first step in reducing the psychosocial risk of a person with CAD is to identify those at increased risk. The accurate identification of negative and positive psychosocial factors in people with CAD may initially appear to be straightforward and feasible. Unfortunately, this is often not the case even for healthcare providers who have significant medical training and experience. One study found that less than 25% of persons with CAD and probable depression could be identified correctly by healthcare workers.34 Standardized tools are available to help identify individuals with psychosocial distress, but these are sometimes lengthy and difficult to administer in the clinical setting of a cardiology practice. A recently published landmark article has recommended the use of a handful of basic, open-ended questions to help CV clinicians identify patients in need of further psychosocial risk assessment and treatment (see Table 2).35
As difficult as it may be to identify persons with increased psychological risk factors for CAD, it is even more difficult to identify the method of treating psychosocial risk that is most likely to improve psychosocial health and reduce overall CAD risk at the same time. Behavioral and pharmacologic treatments are available that can effectively help to treat most negative psychological factors.14,15 Unfortunately, treatments aimed at improving psychosocial health may not necessarily reduce CAD-related risk. Results of the Enhancing Recovery in Coronary Heart Disease (ENRICHD) study, for instance, showed that individuals with CAD and depression who underwent an intense behavioral and pharmacologic intervention showed improvements in their depression but not in overall CAD events when compared with individuals who were randomized to a lower intensity 'usual care' control group.36 An unexpectedly low rate of CAD events in the usual care group appears to explain at least some of the negative outcome of the study.
The Sertraline Anti-Depressant Heart Attack Randomized Trial (SADHART) study, another similar randomized, controlled clinical trial, likewise found that treatment of depression did not translate into an improvement in CAD events in people with a previous history of MI and depression.37 It should be noted that the SADHART investigators designed the study as a safety study and did not plan it to have sufficient power for assessing the impact on CAD events.
Results from ENRICHD, SADHART, and other studies highlight the aforementioned dilemma in current behavioral cardiology—some psychosocial factors associated with an increased risk of CAD are treatable, yet their treatment may not reduce CAD risk. Results of an observational sub-study from the ENRICHD study have increased the hope of finding a solution to this dilemma. In this observational study arm of the ENRICHD clinical trial, persons who were treated with selective serotonin reuptake inhibitor (SSRI) anti-depressant medications were found to have a lower risk of CAD events in the follow-up period than those who were treated with other anti-depressant therapies.38 Other studies have also suggested that the identification and treatment of persons with psychosocial distress can reduce subsequent CAD events, either through treatment of psychosocial factors or the aggressive treatment of other more traditional CAD risk factors.7,13,39,40 It is theorized that psychosocial treatments, such as SSRI agents, may lead to improvements in the physiologic steps that link CAD and psychosocial risk (autonomic nervous system function, for instance). In the future, randomized studies are anticipated that will explore the potential impact of SSRI therapy on psychosocial and CAD outcomes.
Ironically, another treatment that may prove to be very effective in behavioral cardiology of the future is one that has been used for CAD prevention and treatment for many years—physical activity. Physical activity interventions have been reported to help improve psychosocial distress and CAD outcomes. This may help explain why cardiac rehabilitation programs are associated with improvements in psychosocial and CAD health outcomes.35
Positive psychosocial factors represent an area of large potential impact for intervention studies in the future. Interventions that may increase positive psychosocial factors, such as optimism and sense of humor, may improve psychosocial health and improve CAD risk. Perhaps most importantly of all, such interventions may help improve CAD outcomes by increasing a patient's adherence to important prescribed therapies.
As of yet, interventional studies are scarce that have explored interventions to increase optimism, sense of humor and other positive emotions,41,42 but, on the other hand, physical activity interventions have demonstrated improvements in mood and sense of wellbeing.43 In addition, effective and feasible methods to help patients increase their adherence to preventive therapies have been identified and validated.1,44-46 If such interventions can help improve therapies of known effectiveness, such as lipid lowering therapy and anti-hypertensive therapy—two areas of treatment that are vastly under-prescribed by healthcare providers and under-utilized by patients—then they could substantially help reduce rates of CAD events in the future.
Putting Behavioral Cardiology into Clinical Cardiology Practice
Despite limitations to current knowledge about which psychosocial interventions reduce CAD risk the most, it is clear that the time for behavioral cardiology in current clinical cardiology has arrived.1,2 The impact of psychosocial factors on treatment adherence alone warrants an increased focus on behavioral cardiology by CV clinicians. The application of these principles will become increasingly important as quality of care indicators and outcome report cards become a standard part of clinical cardiology.
Population and societal trends foreshadow a growing population of individuals with chronic CAD and increasing expectations that clinicians will provide appropriate psychosocial care for their patients at risk for CAD events. To overcome patient, provider, and systematic barriers and to successfully implement effective screening and treatment methods, further research in behavioral cardiology barriers and implementation is needed. There is also an immediate need to provide clinicians with screening and treatment guidelines and tools that are simple, effective, and user-friendly. Based on current levels of knowledge, several components emerge that can help busy clinicians integrate pertinent behavioral cardiology principles into a clinical practice. These include:
- building group consensus around the need for improving behavioral cardiology components in practices;
- identifying key psychosocial factors to be screened, and the screening tools to be used;
- incorporating screening and treatment guidelines into practices, using streamlined processes, effective communications and reminder tools, and appropriately trained clinical staff;
- applying guidelines and assess adherence to them by clinical staff;
- providing feedback to clinicians regarding their adherence to guidelines;
- following-up with patients and assessing their clinical outcomes, satisfaction with their care, and adherence to recommended therapies; and
- updating practice guidelines regularly based on feedback from clinicians and patients.
Conclusions and Future Needs
The evidence linking psychosocial factors to CAD risk is strong—both negatively and positively. Some psychosocial treatments have failed to improve CAD outcomes in people at risk for CAD events, but other treatments involving physical activity or SSRI antidepressant medications show promise for improving psychosocial distress and CAD events in persons who are at risk for both. Population and societal trends will increase the importance of behavioral cardiology in the practice of clinical cardiology and will increase the need for simplified, user-friendly clinical models, which can help apply psychosocial screening and treatment to appropriate patients.