Evaluation of a multifactorial rehabilitation programme on lifestyle behaviour and secondary prevention in patients with coronary artery disease

Abstract

The objectives of the present work have been to study the effects of a multifactorial rehabilitation programme on rehabilitative and secondary prevention endpoints in patients with coronary artery disease. The programme focused on lifestyle and behavioural changes (smoking, diet, exercise and stress) and was initiated by a four weeks residential stay followed by an eleven months structured follow-up period. The specific aims and results have been the following:

Study I: To describe the feasibility of the programme 292 patients with either acute myocardial infarction, coronary artery bypass surgery or percutaneous transluminal coronary angioplasty (PTCA) were included. Positive effects were seen in lifestyle and behavioural changes as well as medical risk indicators after one and 12 months. The study, which lacked a control group, is to be considered as a pilot study.

Study II: In a randomised study to evaluate effects on achieved lifestyle and behavioural changes after 12 months and relate these changes to the outcome of secondary preventive end-points. Out of a consecutive population of 151 patients treated with PTCA, 87 were randomly allocated to an intervention (n=46) or to a control group (n=41). In both groups morbidity was low, symptoms few and rate of return to work high. The intervention group improved significantly more in several lifestyle dependent behaviours corresponding to an improved exercise capacity and weight loss of 1.6 kg. Psychological variables revealed only minor changes between groups.

Study III: In the same patient population as study II to evaluate the effects of maintenance of achieved lifestyle and behavioural changes after an additional year of follow-up and to relate these changes to the outcome of secondary preventive end-points. During the second year a trend towards lower morbidity was seen in the intervention group compared with the control group. Several life style dependent behaviour changes were maintained in the intervention group. However, the control group attenuated the gap by a gradual improvement over time. After two years exercise capacity in the intervention group still had improved significantly but other medical risk factors as blood lipids, weight, and blood pressure were not different between the groups. Psychological variables revealed only minor changes between groups.

Study IV: To evaluate the effect of the programme on progression of coronary atherosclerosis assessed by means of quantitative coronary arteriography (QCA). Out of the 87 patients 73 with available angiography films at inclusion and after two years of follow-up were included. Minimum lumen diameter (MLD) decreased significantly less in the intervention (-0.03 mm) than in the control group (-0.09 mm). However, mean lumen diameter and percentage stenosis did not differ significantly between the groups. Combining the intervention and control groups change in exercise habits related positively and change in weight negatively with change in MLD.

Study V: To describe associations between known risk factors and measures of heart rate variability (HRV) and evaluate the applicability as regards disease progress or regress. Applying necessary quality criteria on the ECG recordings from 63/87 patients at inclusion and 48/87 both at inclusion and after two years of follow-up were included. Exercise capacity, type A behaviour and high-density lipoprotein levels associated positively with HRV while norepinephrine, neuropeptide Y and low-density lipoprotein levels demonstrated an inverse association. Changes in HRV over time associated negatively with changes in systolic blood pressure, body mass index, low-density lipoprotein cholesterol, neuropeptide Y and norepinephrine, and positively with change in high-density lipoprotein level. Finally, a proportionally high HRV related to decreased cardiovascular morbidity as defined by the need for hospitalisation. The observed associations were biologically relatively weak. The results suggest that this method is unsuitable for clinical monitoring of patients such as ours.

Conclusions: This programme induced favourable but modest changes in a number of parameters considered important for rehabilitation and secondary prevention of patients with coronary artery disease. However, "time trends" attenuated the initial achieved gap between those subjected to the programme compared to those in routine care. Before being generally recommended the programme ought to be revised regarding some of its content. Effects on morbidity and mortality can not yet be fully evaluated.