Causal Model of Physical Activity Among People with Acute Coronary Syndrome After Percutaneous Coronary Intervention: A Cross-sectional Study

Physical activity is considered a fundamental component of cardiac rehabilitation programs and is recommended to improve the secondary prevention outcomes of people with acute coronary syndrome after percutaneous coronary interventions. However, the physical activity levels of this population are often low. Most research studies have primarily focused on older populations and chronic diseases. This descriptive cross-sectional study aimed to test a causal model of physical activities among adults based on the Health Action Process Approach. Four hundred twenty-four people were recruited using multi-stage sampling from the outpatient departments of seven tertiary hospitals in Thailand. Data were collected using a demographic data form, the International Physical Activity Questionnaire-Long form, the Self-Efficacy Questionnaire, the Outcome Expectation Questionnaire, the Risk Perception Questionnaire, the Behavioral Intention Questionnaire, the Planning Questionnaire, and the Action Control Questionnaire. Data were analyzed using descriptive statistics and structural equation modeling with Mplus software. The findings of our study hold significant promise for patient care. The model we tested, which accounted for 46% of the physical activity variance, underscores the crucial role of self-efficacy, planning, and action control in directly influencing physical activity. Notably, self-efficacy was found to exert the most profound effect. Outcome expectation was shown to influence physical activity indirectly through intention and planning. This highlights the potential for nurses to design interventions that foster self-efficacy, plan­ning, and self-regulatory strategies. These strategies can empower patients to overcome challenges in cardiac rehabilitation and maintain physical activities, thereby improving their health outcomes. However, it is important to stress that our proposed intervention should be rigorously tested for effectiveness before implementation.