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theses

Coronary artery bypass graft (CABG) surgery is a commonly performed treatment for coronary artery disease that reduces cardiac symptoms and improves quality of life (QOL) in many patients. While heart surgery typically improves cardiovascular function it does not always improve patients’ QOL. One aspect of poor QOL, high levels of depressive symptoms, is also an important psychological predictor of recurrent cardiac episodes. Accordingly, this study examined psychological factors influencing post-surgical depression and other QOL measures. It evaluated the role of dispositional optimism in predicting post-surgical QOL and the processes by which the two are related. A total of 570 heart surgery patients were included in the study. Based on previous theory and research, Hypothesis 1 predicted a positive linear association between pre-surgical dispositional optimism and post-surgical QOL and Hypothesis 2 predicted a quadratic association such that moderate optimism would be more strongly associated with positive outcomes than high or low optimism. As cardiac symptom improvement is expected after CABG, distress was expected to occur if expectations were not met. Accordingly, Hypothesis 3 predicted that highly optimistic patients whose cardiac symptoms did not significantly improve after surgery would experience significant distress. Hypothesis 4 predicted that self-care self-efficacy, expected consequences, perceived social support, and coping responses would mediate the optimism-QOL association. These variables have separately been shown to be associated with optimism and health outcomes in other studies. The results showed a positive linear association between optimism and 3-month depression. There were no other significant linear or quadratic associations between dispositional optimism and 3-month post-surgical QOL. Change in cardiac symptoms did not moderate the association between optimism and post-surgical distress. Lastly, there were several significant indirect effects between dispositional optimism and 6-month QOL. Significant mediators included: perceived social support, self-care self-efficacy, expected consequences, positive reinterpretation coping, and meaning-focused coping. These analyses address theoretically important questions and the results have implications for research involving interventions to improve outcomes following cardiac surgery.

ETD_6364

M.S.

Includes bibliographical references

by Jeremy Engelberg

doi:10.7282/T3QN68N8

ETD graduate

The author owns the copyright to this work.