Sleep in patients with coronary artery disease : a polysomnographic study

In this thesis sleep, psychological symptoms and quality of life (Qol) in patients undergoing coronary artery bypass grafting (CABG) at the University Hospital in Linkoping were evaluated. Interviews and 24-hour polysomnography were performed prior to surgery, immediately after surgery and again at one month, with a six-month-follow-up mailed questionnaire. Habitual sleep was evaluated using the Uppsala Sleep Inventory questionnaire and a diary the recorded mornings. The Spielberger State of Anxiety Scale and the Zung's Self-rating Depression Scale were used to measure anxiety and depression, respectively. Physical functional capacity was assessed according to the New York Heart Association's (NYHA) classes and Qol, with the Nottingham Health Profile instrument (NHP). A retrospective evaluation of nurse's documentation about sleep was also performed. In addition, the quality and quantity of sleep were assessed before surgery and in the immediate postoperative period in a pilot study, with a one-month follow-up interview. The results indicated disturbed sleep, and changes in behaviour and mental state after surgery due to fragmented sleep, pain and anxiety. Forty-four patients were examined prior to surgery. The results showed that almost two-fifths experienced too little sleep habitually and 50 % had a combination of at least two sleep problems. Poorer health, higher level of anxiety and increased difficulties maintaining sleep (DMS) were consistent with significantly longer sleep latency, increased fragmented sleep, and reduced stages 3 and 4 and RIM sleep measured by polysomnography. The level of Qol on the NBP was significantly associated with objectively measured sleep. In the immediate period following CABG there is a changed distribution of sleep, with a reduction of nocturnal sleep duration and an increase in daytime sleep, which had almost returned to preoperative values one month after surgery. Qol was significantly improved six months after surgery compared to before surgery. It was noted that patients with a more anxiety prone reactivity during six months following CABG had significantly more sleep disturbances, reduced energy and functional physical capacity, and lower quality of life, compared to those without such reactivity. Significantly more sleep disturbances, reduced energy and lower quality of life were more prominent among those with sadness/depression or cognitive/behavioural fatigue as reactions to sleep loss. A higher degree of cognitive/behavioural fatigue and dysphoria reactions were associated with a higher NYHA class. In conclusion, patients with coronary artery disease have poor quantity and quality of sleep. Increased psychological symptoms in patients with CAD prior to surgery were associated with greater symptoms six months after surgery. Physical functional capacity and quality of life were significantly improved six months after surgery.