Can Preoperative Quality of Life Predict Adverse Outcome of Coronary Artery Bypass Surgery in the Elderly?

1- Hermineh Aramin, MD., Tehran University of Medical Sciences, Tehran, Iran
2- Mehrdad Sheikhvatan, MD., Tehran University of Medical Sciences, Tehran, Iran
3- Mahmood Sheikhfathollahi, Biostatistician, Tehran University of Medical Sciences, Tehran, Iran

Correspondence:
Hermineh Aramin
No. 2, Chenaran Street, Elahieh, Tehran, Iran
Tel: 0098-21-22605884
email: msv_swt@yahoo.com

INTRODUCTION

The structure of the definition of Quality Of Life (QOL) is mainly based on the individual's perception of his/her position in life regarding sense of well-being, meaning, and value of self-worth^[1]. This self-perception can be influenced by several factors such as gender, age, self status, and cultural factors. Among these factors, age has the most important role because of disability to change health attitude, behavior, and lifestyles in the elderly^[2].

These age groups sufferer from chronic disorders such as acute coronary syndrome and the adverse events of these disorders have been known to be higher in older patients than those younger. Therefore, it seems that the age factor can be an important predictor for outcome of cardiac interventions and can effectively determine postoperative complications such as high morbidity and prolonged length of stay in hospital and also in intensive care units^[3,4].

According to the fact that a strong relationship has been proved between age and different aspects of QOL and also the potential effects of the age factor on outcome of cardiac surgeries, patient's baseline QOL may have a pivotal role to predict this outcome in the elderly.

We tried to assess this hypothesis in patients undergoing isolated coronary artery bypass graft surgery (CABG) in a sample of older patients among the Iranian population.

METHODS

In a prospective study, 71 patients ranging from 60 to 80 years old and who underwent pure CABG at a private hospital in Tehran in 2007 were consecutively entered into the study. Patients who underwent other cardiac or non-cardiac procedures were excluded. The study was approved by the Research and Ethics Committees of Tehran University of Medical Sciences and all individuals signed an informed consent form before taking part in the study. Baseline characteristics and clinical data of patients including general information, risk factors for coronary artery disease and cardiac status were collected using a self-administered questionnaire on admission day. Patients' QOL was assessed using SF-36 questionnaire by patient interviewing before surgery. The SF-36 questionnaire is a 36-item tool that covers eight dimensions including physical function, role emotional, role physical, bodily pain, vitality, general health, social function, and mental health^[5]. We also considered the two scores of physical and psychological component summary scores.

Our study focused on the effects of different QOL components on early morbidity after CABG. Morbidity was defined as the existence of at least one of these complications: wound infection, dysrrhythmias, brain stroke, respiratory failure and myocardial infarction.
Continuous variables were shown as mean±SD and categorical variables were indicated as percentages. Relationships between morbidity and each of the components of QOL were determined using t test for variables with normal distribution or Mann-Whitney U test for other variables. P values of 0.05 or less were considered statistically significant. All statistical analyses were performed using SPSS version 15.0 for Windows.

RESULTS

View Figure 1 and 2

The mean age of patients was 67.39 years and 33.8% of them were female. Mean of body mass index was 27.47 kg/m² and ranged between 19.7 and 38 kg/m². The most common risk factors for coronary artery disease were hyperlipidemia and hypertension (Table 1).

Table 1 General characteristics and clinical data of studied patients (n=71)

More than half of the patients had functional class III and also most of them had three involved coronary arteries. Although in-hospital mortality was found only in one patient (mortality rate 1.4%), morbidity rate was estimated at 53.5% (Table 2). Postoperative arrhythmias and respiratory failure were commonly observed in the studied patients; however postoperative myocardial infarction and brain stroke were rare.

Table 2 Postoperative morbidity in studied patients (n=71)

Among different components of QOL, social functioning and role physical had the highest and lowest scores (Figure 1). Among these eight dimensions, only means of the two scores of social functioning and bodily pain were higher than 75%.

Comparison of QOL scores between the groups with and without early morbidity found no statistically significant differences in all component scores between the two groups (Figure 2).

DISCUSSION

There are several sets of evidence about expectation of older patients to experience more difficulties after cardiac surgery with an appropriate clinical outcome^[6]. Therefore, determination of factors affecting the life of these patients is vital and necessary. One of these factors may be the patient's perception of life and feelings about himself or herself. In the present study, we obtained two main results: firstly, we found that among different aspects of QOL, role physical had the lowest scores. It seems that the perception of patients with CAD about their physical ability and functional capacity is dramatically poor and this unacceptable view can adversely influence cardiac and non-cardiac events due to the progression of CAD. In a study by Nejati et al. (April 2008) in Iran, the lowest score of QOL was related to physical role in both genders, whereas the highest scores were related to mental health and social function^[7]. The relationship between physical disability and depressive disorders especially in older men with CAD was previously shown^[8].

According to this fact that most of the studied older patients in our study had high function class and also three coronary arteries involvement, patients' attitude toward their physical ability and physical role in life can be related to the severity of their illnesses so that the patients with severe disability due to severe CAD and its complications notably have poorer attitudes towards their physical role than the patients with early onset CAD.

Another finding of this study was that preoperative QOL of older patients who underwent CABG did not affect the postoperative complications. Similar finding have been obtained in the Najafi et al. (December 2008) study^[9]. Although it seems that the patient's view about their physical and mental situation may have a major effect on outcome of surgery, other factors such as gender, CAD risk factors, medications, and surgical techniques have a more effective role on this outcome, especially in the elderly. It has been clear that the elderly are usually symptomatic yet at high risk for intervention^[10]. Also, it has been found that most of the preoperative CAD risk factors such as hypertension, preoperative cerebral vascular accident, diabetes mellitus and hyperlipidemia are more frequent in older patients than the younger^[11] and this difference can potentially lead to worse postoperative outcomes in the elderly than other age groups. Therefore, it seems that the predictive power of these risk factors on poor postoperative outcome especially in older subjects may be higher than different aspects of preoperative QOL. However, further studies using greater sample size are recommended to highlight the role of patient's perception and his or her psychological status on postoperative outcome.

In conclusion, patients older than 60 years have poor physical role and appropriate social function before CABG, however different aspects of QOL before cardiac surgery may not influence postoperative early outcome.

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