DISCUSSION

This study compared the quality of life (QoL) of patients with unstable angina before and after being treated with PCI and investigated the factors associated with improvement after treatment. The results indicated that PCI led to improved QoL in most of the health concepts categorized by the SF-36 questionnaire except for the social functioning and mental health aspects. The findings are comparable with a study by Wong et al19 which demonstrated an increase in all the eight domains after one month of PCI, and even after 3 months in several domains. Before the intervention, the patients reported experiencing significant problems with daily activities due to their physical limitations, moderate bodily pain, and fatigue. This is in line with another study on Australian and Danish populations showing quite similar pre-intervention QoL score to our results.26Moreover, this study also found that 27% of the patients reported a decrease in the subscale of mental health, which reaffirmed the patient’s decline of mental health QoL score in our result26. This decrease in the mental health aspect of quality of life could be due to unstable mental status and fear of post-operation complications, which led them to fall into stress and anxiety shortly after the intervention. This condition would improve over time as the patient’s health stabilized again. Our results reflected this situation as the QoL score for mental health, and social functioning aspects dropped remarkably one month from intervention and started to rise again after three months, even if it was still lower than before the intervention. Our study shows that QoL of patients with coronary heart disease may be significantly affected by patients’ mood disorder even where methods of intervention are physically beneficial, and more attention to mental and social support after intervention may be warranted.
In our study, the results also indicated that some demographic factors were associated with the QoL improvement resulting from PCI. As expected, older people and people in rural areas had lower QoL across the time period of the study. It is because they may have more difficulty to access to better facilities for health care. In Vietnam, it’s true as the health system that serves the elderly is limited which could affect health care. This result was found in several previous studies showing higher mortality rates after PCI in older than in younger patients. In fact, in several interventions, advanced age was associated with worse short-term prognosis and higher rates of complications.28-30 The justification for this may be that multiple comorbidities, including chronic kidney diseases, that older patients often suffer from, were increased risk factors for PCI.31 Besides, in the study of Shanmugasundaram, physiological factors were also considered to influence on the outcome after PCI, age caused an increase vascular stiffness, which in turn results in hypertension, left ventricular hypertrophy, and decreased left ventricular function.31 Even myocardial diastolic function becomes impaired with aging, and endothelial dysfunction is more common.31 In addition, another factor that was related to the QoL improvement resulting from PCI was occupation. It is true that retirees be more likely not to improve their QoL after the treatment than the working people (workers, freelancers, farmers, home-makers, etc.). One justification for this may be that people being retired would undergo a series of emotional and the salary level changing. Therefore, they would be less likely to reach a better outcome after PCI. However, it is not surprising that retirees living with pension had better QoL than other older age groups.32 The study of Isabelle Hansson et al also showed that retirees reported having an increase in life satisfaction and a higher degree of autonomy due to sufficient financial capacity after one year of retirement.33 This could be explained by the fact that older people with stable financing would be able to focus more on their regular health care and participate in social and cultural activities which might enhance their psychological as well as physical QoL. The working group would have less time to recover from the intervention than the retirees since they had to return to their job duties as soon as they could. This elucidates the similarity of QoL improvement between the groups on the end of the first month after the treatment, and the higher likelihood of QoL improvement of the retirees compared to other occupation groups after three months. Therefore, it is necessary for further research to declare the impact of this factor on PCI outcome. Our study also found a factor that had impact on the effectiveness of PCI was the place of residence. The elderly living in rural area were 4.45 times less likely to improve their QOL after PCI than the people living in urban area. This result was similar with the finding of the previous study.34 They found that ST-elevation myocardial infarction (STEMI) guidelines recommend reperfusion by PCI with less than or equal to 90 minutes from time of first medical contact (FMC). This strategy is challenging in rural areas with a lack of nearby PCI-capable hospitals.34 Another study in China35detected that people living in rural areas had limited access to medical services. In cases of high-impact conditions, such as acute myocardial infarction, rural residents are less likely to receive evidence-based therapies and may experience worse outcomes.
We found that abnormal troponin was associated with the setback of PCI outcomes, but other sub-clinical factors are not, consistent with a study by Prasad et al.36 which found that patients with an elevated troponin after PCI had elevated short-term mortality risk. The association between an elevation in troponin and efficacy of cardiovascular diseases treatment was supported by our study.
This study has several limitations. Some of the interviews were partly conducted via telephone, which limited the collection of comprehensive information as we could not observe the facial expression of the interviewees, and some of the questions might have been difficult for them to understand compared to direct face-to-face interaction. The sample may not representative of the concerned population. However, as a quasi-experiment design with repeated measures on the same patients over time, the results could present a strong and valid case for informing both clinical and public health practice.
The results of this study have several implications for care and follow up in angina patients. Firstly, interventions or health care regimens that improve the QoL of patients with unstable angina are needed, and these methods should be prioritized to improve the social functioning and emotional well-being of the patients, especially within the first month after the intervention as this is the period that the patients experience significant drop in their QoL in these two domains. Health care service providers and caregivers are also expected to deliver proper rehabilitation methods and guide lifestyles which can provide the patients with the best recovery after PCI. In addition, healthcare service providers should establish counselling programs that enhance the knowledge and practices about post-operation care of patients. Efforts should also be made to raise patients’ awareness on the adverse impact of smoking and diabetes on the severity of unstable angina as well as the efficacy of PCI treatment.