coronary artery bypass surgery, functioning outcomes, model-based clustering method, symptom cluster, symptom profiles



  1. Zimmerman, Lani PhD, RN, FAHA, FAAN
  2. Barnason, Susan PhD, APRN-CNS, CEN, CCRN, FAHA
  3. Young, Lufei BSN, RN
  4. Tu, Chunhao PhD, Statistics
  5. Schulz, Paula PhD, RN
  6. Abbott, Amy A. PhD, RN


The purpose of this secondary analysis was to profile or cluster 226 patients, who had participated in a randomized controlled trial, on symptoms after coronary artery bypass surgery and to examine how these profiles could potentially be used by clinicians to identify groups at risk for impaired functioning during the first 6 months after surgery. Variables measured were symptom presence and burden and functioning. The model-based clustering method was used for cluster analysis of the symptom burden measure, and analyses of covariance were used to determine if there were differences on functioning (physical functioning and physical activity) by symptom burden group at 6 weeks and at 3 and 6 months after dismissal. The majority of the 226 subjects were married (86%), male (83%), and had a mean age of 71 (SD, 4.96) years. Eight symptoms were used in the model-based clustering method-shortness of breath, fatigue, depression, sleep disturbances, pain, swelling, anxiety, and appetite problems-and demonstrated that there were 3 patient clusters of symptom burden. Cluster 1 had low symptom burden on all 8 symptoms, cluster 3 had moderate symptom burden on all 8 symptoms, and cluster 2 had a combination of low (shortness of breath, fatigue, depression, pain, and anxiety) and moderate symptom burden (sleep problems, swelling, and appetite problems). Analyses of covariance revealed no significant cluster x time interactions for any of the variables. However, there were significant main effects (P < .01) for symptom burden groups for physical functioning (physical and vitality functioning) and physical activity (estimated energy expenditure and mean daily total activity counts). Significant main effects for time indicated physical functioning and physical activity measures, except bodily pain, improved over time (P < .05). Study results indicate that the use of profiling coronary artery bypass surgery patients on their symptoms prior to hospital discharge may assist health care providers to identify patients who could be at risk for having more difficulty with physical functioning and physical activity during the first 6 months after surgery.