Advances in surgical techniques and postoperative care have led to substantial reductions in perioperative mortality and morbidity among cardiac surgery patients.1 Although published data regarding the incidence of perioperative complications after cardiac surgery are plentiful, the literature on the subsequent impact of such complications on patients' long-term health-related quality of life (HRQL) is mixed.2-6
Perioperative morbidity and mortality data have long been used as benchmarks for successful cardiac surgery. In recent years, other tools, such as those which measure quality of life and functional status, have become an integral aspect of cardiac surgery outcome assessment.4,7-9 Results regarding an association between HRQL and mortality among cardiac surgery patients are mixed. The baseline Physical Component Summary score from the preoperative SF-36 has been shown to be an independent risk factor for mortality after cardiac surgery, but the baseline mental component score has not.7 Decreased baseline HRQL using the SF-36 among older patients has been shown to be an independent predictor of 6-month mortality after cardiac surgery when compared with younger patients.10
The purpose of this study was to assess the relationship between perioperative complications and HRQL at 1 year after elective open-heart surgery. In addition, we assessed the association between HRQL scores at 1 year after open-heart surgery and intermediate-term survival.
Materials and Methods
Patients
This was a prospective study of patients undergoing an elective cardiac surgical procedure designed to assess postsurgery functional status changes from baseline to 1 year. The study was approved by our institutional review board.
Any elective surgery patient presenting for elective surgery through our same-day admission clinic was eligible to participate. Participating patients were given a paper questionnaire (20-item short-form [SF-20]) to complete at the time of their clinic visit. Patients were then mailed follow-up questionnaires at 1 year after surgery. The HRQL scores at baseline and 1 year after surgery were reviewed and compared.
Health-Related Quality of Life
Health-Related Quality of Life was measured using the standardized and validated Medical Outcomes Trust SF-20 Questionnaire11 (Appendix 1). The SF-20 measures 6 domains of functional health: physical functioning, role functioning, social functioning, mental health, general health perception, and bodily pain. In addition, an overall score is generated from the average of all 6 domains. All scales are measured as continuous variables from 0 (worst) to 100 (best). Increased scores equate to increased HRQL.
Demographic and Preoperative Characteristics
Demographics examined are age and sex. Preoperative risk factors include New York Heart Association class, smoking (current/former), diabetes, history of renal failure, history of renal failure with dialysis required, family history of coronary artery disease, previous cerebrovascular accident, previous coronary artery bypass graft, previous valve surgery, previous cardiovascular intervention, previous myocardial infarction, previous arrhythmia, and ejection fraction.
Perioperative Complications
Rates were calculated for perioperative myocardial infarction, mediastinitis, superficial wound infection, septicemia, permanent stroke, transient ischemic attack, continuous coma, prolonged intubation, ventilator-associated pneumonia, cardiac tamponade, atrial fibrillation, reoperation for bleeding, renal failure, renal failure which required dialysis, and length of stay. Definitions were defined by the Society of Thoracic Surgeons1 National Adult Cardiac Surgery Database Registry.
Mortality Data
Survival data were collected using the Social Security Death Index. The Social Security Death Index database contains survival data on individuals issued US Social Security numbers by Social Security Administration. Survival time from date of surgery was censored on August 1, 2006.
Statistical Analysis
Continuous data are presented as mean (SD). Categorical data are presented as frequency and percent. Univariate comparisons of preoperative risk factors, demographics, and operative characteristics were performed using the Student t test or [chi]2 analysis, where appropriate. An analysis of covariance was used to predict HRQL scores at 1 year after adjustment for baseline covariates such as baseline HRQL, age, sex, and other potential confounders. Post hoc tests were done via contrasts. Survival estimates at 1, 3, and 5 years were calculated by life-table or Kaplan-Meier methods with survival comparisons performed via the log-rank test. Statistical significance was considered as P <= .05. All analyses were conducted using SAS (version 9.2; SAS Inc, Cary, NC).
Results
Eight hundred thirty-six patients completed the preoperative and 1-year postoperative questionnaire (SF-20) (Figure 1); One hundred thirty-three patients underwent a valve procedure; 620 underwent coronary artery bypass grafting; 67 patients underwent coronary artery bypass grafting plus valve procedure; 15 patients underwent coronary artery bypass grafting plus other cardiac procedure; and 1 patient underwent closure of an atrial septal defect. Patient demographics and clinical characteristics of both participants and nonparticipants are presented in Table 1. Eighty-three percent of the participants are male, and average age was 63 years.
Perioperative complication rates can be found in Table 2. The average number of complications per patient was 0.29. Seventy-seven percent of all patients experienced no perioperative complications; 23% experienced 1 or more complications.
Patients reported improved HRQL in all domains at the 12-month follow-up (Table 3). The largest absolute gain was documented in the general health perception domain with an average positive change of 19.4 (SD, 24.2). The least gains were shown in the social functioning and mental health domains with increased scores of 5.1 (SD, 23.3) and 5.1 (SD, 17.2), respectively. All changes in scores were significant when compared with baseline (P < .001).
When stratified by the presence or absence of 1 or more complications, no statistically significant changes were observed between groups after adjustment for age, sex, and severity of disease (Table 4). Patients in both groups experienced statistically significant increases in HRQL for all domains. The largest increases for both patient groups were observed for the domains of general health perception (no complications, +19.5; >=1 complications, +19.5) and physical functioning (no complications, +13.7; >=1 complications, +13.2). Domains with the least change from baseline were mental health (no complications, +4.9; >=1 complications, +5.9) and social functioning (no complications, +4.9; >=1 complications, +5.7).
There were no significant preoperative or perioperative predictors of HRQL scores between baseline and 1 year. Mortality comparisons were begun at the 1-year follow-up time point to determine if HRQL scores 1 year after surgery will predict long-term survival.
Kaplan-Meier curves were estimated for each domain to assess the effect of positive or negative HRQL changes from baseline to 12 months on survival (Table 5; Figures 2-4). Two years after surgery, patients with a positive HRQL change averaged 2.9% greater survival per domain than patients with negative HRQL changes. The greatest disparity was in the role functioning domain (99.5% vs 93.6%, P < .039). Three years after surgery, the difference in survival was even more prominent-a per-domain average difference of 3.4%, with the greatest difference in survival in the role domain (98.1% vs 90.3%, P < .0039).
When the numbers of negative changes from baseline are summed by either mental (role functioning, mental health, social functioning) or physical (bodily pain, physical functioning, general health perception) components, subjects with multiple negative changes are at a significantly decreased survival advantage at 5 years compared with patients with no or few negative changes (Figure 5). Subjects with negative changes on all 3 mental component scores experienced 16.5% less survival at 5 years compared with subjects with no decreases on mental components (78.5% vs 95.0%). Similar results were observed for subjects with negative changes on all 3 physical components (80.0% vs 94.7%).
Discussion
Over the past 2 decades, quality of life has become a frequently used outcome measure in clinical and health policy settings.12-20 In this report, we demonstrate that perioperative complications do not necessarily predict diminished HRQL or survival disadvantages after elective cardiac surgery. However, we did find that patients with negative changes in certain HRQL domains may experience a survival disadvantage as early as 2 and 3 years after surgery.
Evidence suggests that after any surgery, the majority of patients will return to their predisease HRQL.21-23 Research involving HRQL after surgery shows that the most significant predictors of decreased HRQL after surgery are related to preoperative comorbidities such as age, sex, congestive heart failure, and myocardial infarction. In addition, preoperative HRQL perception such as a despondent or an angered state or a clinical diagnosis of depression has also been identified as an independent predictor of diminished postoperative HRQL.4,24,25 Several reports have demonstrated a correlation between increased length of stay and the decreased HRQL among patients immediately after surgery.2,25
Koch et al26 demonstrated that serious perioperative infection is associated with decreased HRQL at 1 year. Among our patients who experienced mediastinitis, we found lower HRQL scores at 1 year on their pain score domains. Pappalardo et al5 reported prolonged ventilation after cardiac surgery as being a predictor of decreased HRQL. However, no significant changes in HRQL at 1 year were observed among our patients with prolonged ventilation time (>24 hours).
Perioperative stroke after coronary artery bypass grafting has been reported to predict decreased HRQL.27-32 In our study, those who experienced a permanent stroke did, in fact, report worse scores at 1 year, but only in the social domain. Large differences in the mean change of the general health perception, physical, and overall domains were observed between those patients with and without a perioperative permanent stroke. Previous studies reporting health and physical domains suggest that patients experiencing a perioperative stroke have increased adverse outcomes and decreased HRQL after surgery. Although we did not find statistical significance, we believe that permanent stroke is a major complication with the potential for a significantly negative impact on long-term HRQL.
In general, patients reported improved HRQL in all domains at 12-month follow-up, with the largest in the general health perception domain and the least in the social and mental domains. Although there were no statistically significant changes in HRQL between those patients with no complications and those with 1 or more, all patients did experience statistically significant increases in HRQL for all domains. The domains of general health perception and physical demonstrated the largest gains and the domains of mental and social demonstrated the least gains.
Of note, results suggested that patients experiencing negative changes in HRQL (eg, domains: role, general health perception, social, and overall) at 1 year after surgery had higher mortality later in the follow-up. These findings are extremely interesting especially with regard to the negative impact of decreased scores in the social and role domains on late survival. Furthermore, when the data were stratified by the number of positive or negative HRQL changes, subjects with multiple negative changes are at a significantly decreased survival advantage at 5 years compared with patients with no or few negative changes.
Previous research supports the premise that perceived state of mind has a deleterious effect on survival.33-37 Cooper et al33 demonstrated that among older patients, perceived health was associated with increased mortality, although cardiac patients experienced no more or less an association than other disease subgroups.34 Glassman and Shapiro34 and Knight,35 however, reported that among cardiac patients, the association between depression and mortality was prominent. In addition, Oxman et al36 found that older persons who lack participation in social or community groups or find no comfort in religion are independently at an increased risk for death during the 6 months after surgery.
Our findings may suggest that future studies should be designed to assess the possible association between psychosocial status and late survival after cardiac surgery. Significant findings may lead to a different approach in community support of patients after surgery.
Limitations
It is important to note that our patient population consists of elective same-day admissions and thus somewhat differs from that of other published studies. Elective open-heart surgery patients generally represent the healthiest case mix of cardiac surgical patients and may not be generalizable to patients of other institutions.
Practical Applications
Nurses should be cognizant of increased patient expectations and attempt to be realistic in patient education regarding recovery time. Discharge education and planning should include a formal dialogue with the patient regarding duration or recovery and the potential for setbacks. We suggest several roles for the nursing staff.
1. Educate nursing staff on HRQL findings and trends to allow a more realistic dialogue with the patient. Recovery is most likely not achieved in several months, and in fact, some patients may take at least a year.
2. Identify and communicate with case management (or proxy) about those patients with poor preoperative HRQL scores before surgery to allow discussion regarding discharge planning, social support, and follow-up strategies.
3. Introduce HRQL discussion involving patients with low HRQL as part of the routine in-hospital, multidisciplinary rounds in intensive care unit and step-down services.
4. Continue patient contact for 1 postoperative year. Establish a routine follow-up program that may be as detailed as HRQL assessment or as simple as a follow-up phone call.
5. Investigate use of e-mail, Internet access, telehealth or telemedicine to provide education and promote disease management and education.
Conclusion
In summary, in this prospective cohort assessing the association between HRQL at 1 year after elective cardiac surgery, perioperative complications, and long-term mortality, our study demonstrates that perioperative complications had minimal or no effect on HRQL at 1 year, but patients with decreasing HRQL after surgery may experience a survival disadvantage at 2 and 3 years after surgery.
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