Risk Management in Persons at Risk for Atherosclerotic Cardiovascular Disease (Primary Prevention)

Atherosclerosis is a chronic progressive disease, which commences at an early age.  The majority of acute myocardial infarctions are precipitated by rupture of a non-flow limiting atherosclerotic plaque.  Therefore, efforts to reduce the incidence of acute myocardial infarction should ideally commence prior to the development of symptoms or signs of myocardial ischemia (that is, in a primary prevention setting).  To facilitate this, we have adapted our secondary prevention program for use in persons at risk for atherosclerotic cardiovascular disease by virtue of the presence of risk factors.

The basic approach to comprehensive cardiovascular disease risk management utilized by us for persons at risk for atherosclerotic cardiovascular disease is summarized in Figure 2.  As for our secondary prevention program, the cardiovascular disease risk management action plan is formulated primarily in accordance with published American Heart Association guidelines (Tables 1 and 2).  Other key similarities and differences between the two programs are summarized in the Figures and Tables.

In an attempt to increase access to the program, it has been designed in a manner which enables it to be administered in a variety of clinical and community-based settings.  Currently, the program is administered at two local hospitals and at a shopping mall.  Regarding the latter, shopping malls are conveniently located, easily accessible, indoors and not subject to adverse weather conditions, and provide a relatively safe environment where program participants can walk for exercise.

The program is administered by appropriately qualified non-physician health care professionals who are guided by a computerized patient management and tracking system.  In view of this, and because patients are referred to their personal physician for medication changes, the entire program is administered without direct physician involvement.

The case-management system utilized by the program’s health care professionals includes behavioral interventions derived from several well-established behavior change models, primarily social learning theory and the stages of change model.  Materials and messages are matched with the participant’s stage of readiness for change.  Only on concept or skill is introduced at a time (single concept learning theory), in an easy-to-understand and carefully sequenced way.  At each visit to the program, the participant listens to a 5 to 10 minute behavior modification audiotape, is provided with an educational kit on the specific topic, and meets with the health care professional for further counseling and to update the participant’s individualized lifestyle modification program.  Cognitive and behavioral processes are emphasized to varying extents and in various ways depending upon the participant’s stage of readiness.  Cognitive processes include: increasing knowledge, comprehending benefits of changing a behavior, warning of risks and consequences of not changing and empowering the individual to take action based on internal motivation.  Participants engage in numerous self-assessment and self-monitoring activities, including weighing the “pros” and “cons” of changing, keeping exercise and food diaries, completing stress and smoking logs, and assessing self-efficacy.  Behavioral processes include: counter-conditioning, enlisting social support, using rewards, controlling stimuli and building confidence.  An awards program recognizes individuals who make and sustain positive changes.  Group support meetings and recreational activities provide opportunities to involve others in the change process.  Because participants are at risk for relapse, emphasis is given to planning for high risk situations and dealing with and learning from slips.

The effect of the exercise, nutrition, and combined exercise plus nutrition components of this program on select cardiovascular disease risk factors have been evaluated in two randomized clinical trials.  These studies, conducted in Dallas, Texas and Savannah, Georgia suggest that despite a substantially lower cost, the lifestyle intervention components of our program are at least as effective as 12-weeks of traditional cardiac rehabilitation (Table 3).

Confluence of Primary and Secondary Prevention

The dichotomization of prevention interventions into primary and secondary categories is based upon the identification of symptoms or signs of atherosclerotic cardiovascular disease.  As eluded to above, a meta-analysis of the pathology of acute myocardial infarction has shown that approximately 68% of acute myocardial infarctions arise from the rupture of lesions in coronary arteries that are less than 50% stenosed and approximately 86% of acute myocardial infarctions arise from the rupture of lesions in coronary arteries that are less than 70% stenosed.  Coronary artery stenoses of less than 70% are typically non-flow-limiting, asymptomatic, and challenging to identify.  Clearly, the distinction between primary and secondary prevention of atherosclerotic cardiovascular disease is somewhat arbitrary.  Moreover, as technological advances leading to earlier detection of unstable non-flow-limiting atherosclerotic stenoses evolve, the dividing line between primary and secondary prevention will become less clear. 

In view of this and because many of the interventions comprising cardiovascular risk management are similar for primary and secondary prevention, a natural synergy has evolved between the two programs outlined above.  Once clinically stable, patients with atherosclerotic cardiovascular disease are now often triaged from our “secondary” prevention program to our “primary” prevention program for long-term lifestyle intervention and follow-up, with referral back to our “secondary” prevention program as warranted by their clinical status.  Because of the lower cost and more frequent patient-staff interactions associated with our “primary” prevention program, this has enhanced the cost-effectiveness of our “secondary” prevention program.  We anticipate that the synergy and overlap between the two programs will continue to evolve with time.

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