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Ann Thorac Surg 2005;80:1693-1698
© 2005 The Society of Thoracic Surgeons
Department of Cardiothoracic Surgery, University Hospital, Uppsala, Sweden
Accepted for publication April 25, 2005.
* Address correspondence to Dr Hellgren, Department of Cardiothoracic Surgery, University Hospital S-751 85, Uppsala, Sweden (Email: laila.hellgren.johansson{at}akademiska.se).
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Abstract |
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METHODS: All consecutive patients who underwent primary heart valve surgery from 1998 to 2003 and required 8 days or more of treatment in an intensive care unit (ICU) were included (n = 225). At follow-up on August 31, 2004, 154 of these patients were alive. A cohort (n = 154) matched for sex, age, type of procedure, and week of operation, with an uncomplicated postoperative course (ICU stay of 2 days or less), served as the control group. All patients received the Medical Outcomes Study Short-Form 36, the Nottingham Health Profile, and the Hospital Depression and Anxiety scale to evaluate their quality of life.
RESULTS: Survival at 5 years in the total ICU group was 68% (154 of 225). According to SF-36, the ICU study cohort reported poorer physical health but equal mental health compared with controls. On the Nottingham Health Profile, the ICU group reported more problems in all domains except emotional reactions and sleep. There was no difference in anxiety or depression between the groups. The ICU patients were in more advanced New York Heart Association functional classes preoperatively and postoperatively. No patient in the ICU study cohort regretted undergoing the operation, and 80% experienced improvement after surgery.
CONCLUSIONS: This study showed reduced quality of life in terms of physical health and equal mental health in patients who required prolonged intensive care after heart valve surgery compared with controls without complications.
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Introduction |
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To identify patients at high risk for an unfavorable outcome, scoring systems are used. These might be helpful in the preoperative planning, but they can never fully predict the final clinical result [4]. Moreover, it is not only high-risk patients that suffer from complications postoperatively. A number of low-risk patients will have, although to a lesser degree, a complicated postoperative course and require prolonged intensive care [5]. When patients suffer from complications such as multiorgan failure, maximum therapeutic efforts are often made. Short-term outcome measures such as ICU mortality and hospital discharge are often used to measure the results in these patients. However, hospital discharge, although an indicator of a successful ICU stay, may be an incomplete outcome measure in this group of patients [2]. It must be remembered that even if early survival is achieved, the quality of life (QoL), functional capacity, and long-term prognosis may be chronically impaired [1–3, 5, 6–10].
Little is known about the QoL after discharge from hospital in heart valve surgery patients receiving prolonged intensive care. This study was undertaken to determine whether the quality of life in heart valve surgery patients who needed 8 days or more of intensive care treatment was reduced. A matched cohort with an uncomplicated postoperative course served as a control group.
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Patients and Methods |
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A period of 8 days or more was selected because it represented the top 5% length of stay [11], and to assure a truly complicated postoperative course. These patients, the ICU group, 225 in all, were followed up in terms of survival by computerized linkage to two national registers, the Swedish Cause of Death Register and a continuously updated population register [12] that registers every death within 2 weeks . Using these databases, 154 of 225 patients (68%) were identified as being alive on August 1, 2004. These 154 patients constituted the ICU study cohort. The medical records of the 154 patients were reviewed retrospectively with respect to the occurrence of a complicated course or multiorgan failure postoperatively. Postoperative complications were defined as: (1) respiratory (mechanical ventilation for at least 48 hours); (2) cardiac (two or more inotropic drugs for at least 72 hours or a need for an intra-aortic balloon pump postoperatively); (3) renal (need for dialysis); (4) gastrointestinal (parenteral feeding for at least 5 days); (5) neurologic (neurologic deficit with corresponding lesion at computed tomography); and (6) sepsis (2 of 3 positive microbial blood cultures combined with fever/hemodynamic instability).
Among patients with an uncomplicated postoperative course (ICU stay of 2 days or less) during the same time period (n = 578), a control cohort (n = 225) was formed. The control cohort was matched to the ICU study cohort in terms of age, sex, type of surgical procedure and week of operation. Of the control cohort, 187 of 225 were alive at follow-up. The 154 patients from the control group who matched the 154 patients in the ICU group constituted the controls in the present study. All 154 patients in both groups received questionnaires to allow evaluation of their QoL.
Three sets of questionnaires were used, namely, the Medical Outcomes Study Short-Form 36 (SF-36), the Nottingham Health Profile (NHP), and the Hospital Anxiety and Depression scale (HAD), and in addition the patients received three specific questions by mail. A reminder was sent out 3 weeks later. Incomplete or outstanding forms were followed up with a further telephone call. The patients were ensured that the questionnaires were anonymous.
The study was approved by the Ethics Committee at the Uppsala University Hospital.
Quality of Life Instruments
The SF-36 instrument is designed to evaluate health-related quality of life in multiple groups of patients [13]. It is composed of 36 items, grouped into eight scales, which concern both physical and mental health and assess eight dimensions of QoL. The raw subscale scores are standardized and range from 0 to 100, with 0 representing the poorest state of health and 100, the best possible. Finally, the physical component summary scores (PCS) and the mental component summary scores (MCS) are calculated to summarize the physical and mental state of health.
The NHP [14] consists of two parts, the first with 38 questions or statements aggregated to six dimensions: energy, pain, emotional reaction, sleep, social isolation, and physical mobility. The patients are to give yes or no responses to each question, in relation to restriction of activities or aspects of problems. Each statement is weighted, and a score ranging from 0 to 100 is calculated for each dimension. Each score has the same weight. Accordingly, a score of 0 means no problem in the dimension, and a score of 100 signifies maximal problems. Part two of the NHP lists seven important activities of daily living that are affected negatively if the patient is in a poor state of health. The seven areas are occupation, housework, social life, family life, sex life, hobbies, and holidays. These questions are also answered with yes or no responses. Question number 39 concerning occupation was excluded from the NHP questionnaire as the majority of the patients in this study did not work.
The HAD scale [15] is a brief self-administered rating scale designed to measure anxiety and depression in somatically ill patients. The questionnaire contains 14 items for self-assessment on a scale of 0 to 3. Seven questions are related to anxiety and seven to depression, with a scale range of 0 to 21 for both variables. A score of eight or more on each subscale represents "possible" psychiatric morbidity and a score of 11 or more represents "definite" clinical anxiety or depression. The depression subscale has been constructed so that somatic items are largely excluded.
In the three specific separate questions, the patients were asked (1) if they regretted undergoing heart valve surgery, (2) if they felt they had improved postoperatively the way they had expected, and (3) to grade their functional capacity according to the New York Heart Association (NYHA) classification.
Statistical Methods
Descriptive statistics are presented as mean (± SD). Preoperative baseline variables were compared between groups using Student's t test for means and the 
2 test for proportions. Scoring for the SF-36 questionnaire and imputation for missing items were performed according to the guidelines provided in the Swedish SF-36 manual. After being tested, the scores in SF-36, NHP, and HAD could not be considered to be normally distributed. The Mann-Whitney U test was used to compare scores between the groups. All scores are presented as median (25th to 75th percentile). The change in NYHA class after surgery, compared with before, was calculated with Mc Nemar's test. Correlation was used to test associations between NYHA class after surgery and reported scores. All p values were two-sided and values of less than 0.05 were considered statistically significant in all tests. Statistical calculations were performed with the SPSS statistical package 12.0 (SPSS, Chicago, Illinois).
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Results |
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Short Form-36 Scores
The ICU study cohort reported lower values of summary scores for physical health as compared with the control cohort (p < 0.001; Fig 2). These patients deviated from the control group in all of the eight subscales except one (role emotional). There was no difference in the mental summary scores between the two study groups (p = 0.34).
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Depression subscale
There was no difference in the rate of depression between the ICU study cohort and the control cohort (p = 0.53). Twenty-four patients (18%) in the ICU cohort and 21 (15%) in the control cohort had a score of 8 or more, reflecting possible or definite depression.
Specific Questions
No patient in the ICU study cohort regretted undergoing heart valve surgery, whereas 1 patient in the control cohort reported such regret. There was no difference between the two groups in terms of subjective improvement as expected after surgery; such improvement was noted by 78% and 82% of the patients in the ICU and the control cohort, respectively (p = 0.42).
NYHA Class Before and After Surgery
Preoperatively, the ICU study cohort had a greater proportion of patients in NYHA class IIIB/IV than did the control cohort (p < 0.001) (Fig. 3). Also, before surgery the control cohort had more patients in NYHA class II than did the ICU group (p < 0.0001). After surgery, there was no difference between the groups in the proportion of patients in NYHA class IIIB/IV (p = 0.09), but patients in less advanced NYHA classes (I/II) were more common in the control group (p = 0.01). Both groups improved by an average of one NYHA class by undergoing heart valve surgery. No patient reported a more advanced NYHA class after surgery as compared with before surgery. Moreover, there was no correlation between more advanced NYHA class postoperatively and lower scores in the physical components of either the SF-36 (p = 0.23, r = 0.35) or NHP (p = 0.36, r = 0.24).
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Comment |
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This study included all patients who underwent heart valve surgery from 1998 to 2003 and required 8 days or more in the ICU, of whom 100% had failure of at least two organs, 30% were more than 75 years of age, and 25% were treated at the ICU for more than 15 days. The mortality rate among these patients was high, and 68% were alive for follow-up. The study was undertaken within a defined geographical area and can be considered to be population based. That should therefore permit somewhat valid conclusions to be drawn from this group of patients.
Today there are a number of preoperative scoring systems [16–19] that weight risk factors and are hence used in attempts to estimate the mortality and morbidity related to cardiac surgery. By using these scoring systems, it is possible theoretically to assess the operative risk for each individual patient. However, one must remember that these risk assessments are simply estimates. Thus, irrespective of the score, many presumedly high risk patients do well, and some low-risk patients develop more complications than expected. The outcome after surgery is to a certain extent still unpredictable. If a proper evaluation of the outcome in complicated patients is to be made, it should include more than operative mortality and morbidity, which are measures that poorly reflect the benefit for the patient. A more global analysis of the final outcome should also include survival, QoL, and functional status improvement. These measures combined hereafter form the basis for the discussion as to whether advanced intensive care for selected patients is worthwhile.
Health-related quality of life (HRQL) has become an important component of post-ICU outcome evaluation and has been investigated with different methods. In this study, two validated and reliable HRQL questionnaires were used: the SF-36 [12] and the NHP [13]. These two instruments have been shown to be reproducible and valid for patients discharged from the ICU. To assess the component of depression (which is not covered by the SF-36 or NHP questionnaires), the HAD scale was also used. By the use of three different instruments, in combination with the high response rate, the reliability of the results should be strengthened.
Most earlier studies on uncomplicated heart valve surgery have established that QoL improves with surgery and approximates that of the general population [20–25]. There have also been a few studies on the QoL of cardiac patients with prolonged intensive care necessitated by complications [5–9]. These studies have established that this group of patients has greater impairment of QoL than patients with uncomplicated postoperative periods. However, these studies have generally small sample sizes and coronary artery bypass grafting (CABG) has been mixed with heart valve operations. To our knowledge, no study has been conducted on heart valve surgery patients alone. Also, most studies have used 4 or 5 days as a definition of prolonged intensive care [8, 9]. These studies might be at risk of including a number of patients without a truly complicated postoperative course. The choice of an ICU stay of at least 8 days as an inclusion criterion ensures a complicated postoperative period.
In two studies comparable with ours, the QoL results for patients with a prolonged ICU stay show contradictory results. In the first study [8], on 47 complicated cardiac patients with both CABG and heart valve surgery, the ICU group showed considerably impaired QoL, as measured with NHP, 1 year after hospital discharge. In the second study [9], a subgroup of 131 mixed cardiac patients with complications reported QoL similar to that of the general population, as measured by NHP. Notably, the QoL of our ICU group is comparable with the QoL of the ICU patients in the second study, in other words, comparable with that of their general population. In addition, the rated QoL among our ICU patients is in agreement with scores found by Stoll and coworkers [6] regarding 111 mixed cardiac patients with an uncomplicated postoperative course. From this aspect, we consider the QoL after prolonged ICU treatment in our study to be acceptable. Our ICU group did report somewhat lower physical QoL compared with their controls, but on the other hand, their scores are comparable with those in some studies evaluating patients without complications. However, despite the reported reduced physical function, the ICU group showed equal mental health scores, and rates of depression and anxiety compared with the controls. If the ICU group for some reason had not undergone surgery, the alternative would have been medical treatment, which is associated with an extremely dismal prognosis in symptomatic heart valve patients. Notably, no patient in the ICU group regretted the heart valve operation even though approximately 20% did not experience the expected improvement. It is possible that the patients accept the lack of improvement in light of an awareness of the dismal prognosis inherent in medical treatment.
In the present study, the ICU group had more advanced disease preoperatively, as reflected by a more advanced NYHA class and greater impairment of left ventricular function, than the controls. Both the ICU group and the control group showed functional improvement after surgery by approximately one NYHA class. The lowered physical QoL of the ICU group might be a reflection of their more reduced postoperative functional capacity. However, advanced NYHA class was not associated with reporting low scores in the physical components in either of the two study groups. Also, there was no difference between the two groups regarding the more advanced NYHA classes postoperatively. We therefore believe that a somewhat valid conclusion can be drawn from the reported scores concerning physical QoL. Moreover, the aim of this study was not to compare the QoL of the two groups per se; but to evaluate the QoL of the ICU group. We considered the group of uncomplicated heart valve patients to be a more valid comparison group than the general population.
A major limitation of this study is its cross-sectional design. The follow-up times among the varied to some extent. However, it is known that the majority of patients with prolonged ICU care are restored after a period of approximately 6 months. The mean follow-up time in this study was 38.5 months, but all patients had a minimum follow-up of 8 months. We therefore consider that these results should be an appropriate reflection of their QoL or at least should not overestimate it. On the other hand, the possibility of a certain degree of selection bias must be considered. It is conceivable that only the healthiest patients or the ones most satisfied with the operative result responded to our survey.
In conclusion, the QoL in terms of physical health of patients who required prolonged intensive care after heart valve surgery was reduced as compared with that of uncomplicated controls. Regarding mental health, the QoL was equal in the two groups. A complete evaluation of patients with a complicated postoperative period should include measures that reflect the benefits for the patient, such as QoL and improvement in functional status. Doing so will result in a better global analysis of the outcome than provided by measures such as mortality and morbidity alone.
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  M. Gaudino, F. Girola, M. Piscitelli, L. Martinelli, A. Anselmi, C. Della Vella, R. Schiavello, and G. Possati Long-term survival and quality of life of patients with prolonged postoperative intensive care unit stay: Unmasking an apparent success J. Thorac. Cardiovasc. Surg., August 1, 2007; 134(2): 465 - 469. [Abstract] [Full Text] [PDF]
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8 days; solid circles) and for all patients without complications (n = 225; with intensive care unit stay 
2 days; open circles) undergoing primary heart valve surgery 1998 to 2003. (N = patients at risk in both groups.)
