Interact CardioVasc Thorac Surg 2008;7:564-568. doi:10.1510/icvts.2007.174144
© 2008 European Association of Cardio-Thoracic Surgery
Institutional report - Coronary |
EuroSCORE predicts health-related quality of life after coronary artery bypass grafting
Pertti Loponena,*,
Michael Luthera,
Juha Nissinena,
Jan-Ola Wistbackab,
Fausto Biancaric,
Jari Laurikkad,
Harri Sintonene and
Matti R. Tarkkad
a Department of Thoracic and Vascular Surgery, Vaasa Central Hospital, 65100 Vaasa, Finland
b Department of Anaesthesiology, Vaasa Central Hospital, 65100 Vaasa, Finland
c Division of Cardiothoracic and Vascular Surgery, Department of Surgery, Oulu University Hospital, 90230 Oulu, Finland
d Department of Cardiothoracic Surgery, Heart Center, Tampere University Hospital, 33520 Tampere, Finland
e Department of Public Health, University of Helsinki, P.O. Box 41 00014 University of Helsinki, Finland
Received 20 December 2007;
received in revised form 3 March 2008;
accepted 25 March 2008
 This study was supported by the Medical Research Fund of Vaasa Hospital District.
*Corresponding author. Tel.: +358 50 527 3830; fax: +358 6 323 1678.
E-mail address: pertti.loponen{at}pp.inet.fi (P. Loponen).
 |
Abstract
|
|---|
Three hundred and two patients were evaluated for the EuroSCORE risk and health-related quality of life (HRQoL) during three years after CABG as assessed by the 15D instrument. Both additive and logistic EuroSCORE correlated significantly with the 15D score at 6, 18 and 36 months. A clinically important increase  0.03 in the 15D score was achieved by 50.6% of patients at 6 months, 40.0% at 18 months and 35.9% at 36 months. The rates were similar among patients with increasing EuroSCORE at 6 and 18 months, but tended to decrease at 36 months in the highest EuroSCORE group (EuroSCORE 0–2: 46.8%; 3–5: 34.8%; and 6–14: 33.3%, respectively, P=0.13). Both additive (area under the receiver operating characteristic curve, AUC: 0.582, P=0.024) and logistic EuroSCORE (AUC: 0.575, P=0.039) were predictors of a significant increase of the 15D score. The best cut-off value of the additive EuroSCORE for prediction of a clinically important improvement of the 15D score during 3-year follow-up was 3, as 46.7% of patients with EuroSCORE 0–3 and 30.1% of patients with a score >3 (P=0.006) improved clinically. The present study showed that the EuroSCORE also predicts long-term HRQoL after CABG.
Key Words: EuroSCORE; Myocardial revascularization; Quality of life
|
1. Introduction
|
|---|
The European system for cardiac operative risk evaluation score (EuroSCORE) was introduced for stratification of operative risk of mortality for cardiac surgery [1]. Both additive [1] and logistic [2] form has demonstrated the feasibility of predicting immediate postoperative death after coronary artery bypass surgery (CABG) [3]. EuroSCORE has also been shown to be reliable in assessing long-term survival [4, 5], intensive care unit (ICU) stay and costs [6] and other adverse events [7, 8]. In the present study we aimed at determining the value of EuroSCORE to predict health-related quality of life (HRQoL) 36 months after CABG.
|
2. Methods
|
|---|
The patient cohort consists of 302 patients who underwent CABG between October 2000 and January 2003 at Vaasa Central Hospital, Finland. After approval from the Ethical Board had been obtained, patients were considered for prospective evaluation of HRQoL on admission for coronary angiography. Their agreement was confirmed by written consent. At the first visit patients filled in a questionnaire for assessing baseline HRQoL. For re-evaluation, questionnaires were mailed to the patients 6 and 18 months after the operation and the research nurse personally interviewed surviving patients after 36 months postoperatively.
The 15D is a non-disease-specific measure [9] which has been shown to be a feasible instrument in predicting HRQoL also for CAD patients [10, 11]. It describes the health status along 15 dimensions, which cover the physical, psychological and social aspects of health defined by the World Health Organisation (WHO). The single index score, 15D score, is presented on a 0–1 scale. The maximum score is 1 (no problems on any dimension) and the minimum score 0 (being dead). A change of 0.03 in the 15D score was interpreted as minimum clinically significant change [10, 12, 13].
Patient-related factors, preoperative clinical state and cardiac-related factors were estimated according to the EuroSCORE criteria [1]. Both additive and logistic risk of mortality was calculated for each patient. In the low-risk group (EuroSCORE additive risk 0–2) there were 122 patients, in the medium-risk group (additive risk 3–5) 128 patients and in the high-risk group (additive risk 6) 52 patients.
Operation technique was in 93.7% of cases conventional bypass grafting augmented with cardiopulmonary perfusion, whereas 6.3% of operations were minimally invasive direct (MIDCAB) or off-pump (OPCAB) operations. Time for extracorporeal circulation (ECC) was mean (±S.D.) 104±28 min in the low-risk group, 112±33 min in the medium-risk group and 117±40 min in the high-risk group. Aortic X-clamp time was 86±25 min, 88±29 min, and 90±25 min, respectively. The rather long X-clamp time in all groups is explained by the practice, according to which all anastomoses were performed during single X-clamp, and continuous retrograde tepid blood cardioplegia was used for protection of the myocardium. The practice even allows a quite lengthy aortic occlusion time without compromising the safety of the myocardial protection. Mean number of distal anastomoses among the groups was 3.9±1.3, 4.2±1.1 and 4.2±1.2. Internal thoracic artery (ITA) was used in 96.8%, 92.2% and 82.6% of operations, respectively.
Continuous variables are reported as mean±standard deviation (S.D.). Baseline and follow-up variables were compared using paired samples t-test or analysis of variance (ANOVA). Cumulative survival was calculated using the Kaplan–Meier method and the log-rank test was used to compare survival between patient groups. Differences of 15D scores between risk groups were assessed by the Pearson's  2, Mann–Whitney's and Kruskal–Wallis' tests, as well as the repeated measure test. Correlation between continuous variables was assessed by Spearman's test. Receiver operating characteristics (ROC) curve was used to estimate the predictive value of the additive and logistic EuroSCOREs for any significant increase on 15D score as defined by 0.03 over the preoperative score. Statistical analysis was performed using SPSS statistical software for Windows (SPSS version 14.0.1, SPSS Inc., Chicago, IL). A P<0.05 was considered statistically significant.
|
3. Results
|
|---|
The mean age of the study population was 66.3±9.0 years. 79.1% of patients were male. Clinical variables are reported in Table 1. Table 2 outlines the clinical outcome. The length of stay in the ICU was mean 1.04 days (S.D. 0.20, range 1–2 days), 1.45 days (S.D. 2.36, range 1–23 days), and 4.52 days (S.D. 20.64, range 1–150 days), in the low-, medium- and high-risk groups, respectively (P=0.001). Hospital mortality was 1.0% (one patient in the low-risk group and two patients in the high-risk group). Postoperative stroke, neuropsychological complications (i.e. confusion or delirium), renal failure and atrial fibrillation (AF) occurred significantly more often in the high-risk group. The 3-year survival was 96.7%, 95.3% and 86.5% in the low-, medium- and high-risk groups, respectively (P=0.025).
View this table:
[in this window]
[in a new window]
|
Table 1 Distribution of risk factors in patients undergoing CABG according to different operative risk as assessed by EuroSCORE
|
|
Complete data on the 15D score was available from 263 (87.1%) of patients (92.3% of survivors). In these patients additive EuroSCORE correlated significantly with preoperative (rho: –0.185, P=0.003), 6-month (rho: –0.170, P=0.006), 18-month (rho: –0.224, P<0.0001) and 36-month (rho: –0.271, P<0.0001) 15D scores. Similarly, logistic EuroSCORE also correlated significantly with preoperative (rho: –0.200, P=0.001), 6-month (rho: –0.180, P=0.003), 18-month (rho: –0.223, P<0.0001) and 36-month (rho: –0.275, P<0.0001) 15D scores. The correlation increased along with duration of follow-up.
Fig. 1 shows that the 15D score significantly improved until 6 months (289 survivors, P<0.0001) and despite a decline from 6 months onwards the score was still significantly higher at 18 months than preoperatively (282 survivors, P=0.001). Interestingly, the impairment continued from 18 months onwards and at 36 months after the operation the 15D score approached the preoperative level. 50.6% of patients were improved clinically at 6 months, 40.0% at 18 months and 35.9% at 36 months.
View larger version (9K):
[in this window]
[in a new window]
|
Fig. 1. Graph showing changes (±S.D.) in the15D score during the study intervals compared to preoperative score among 36-month survivors with complete data (263 patients). P-values are according to the Wilcoxon test.
|
|
At all study intervals a significant difference was observed in the 15D scores between the groups of increasing additive EuroSCORE. This finding was confirmed by the repeated-measure test (P=0.001, Fig. 2). However, the rate of clinically significant increase in the 15D score was similar among the risk groups at 6 and 18 months, but tended to decrease towards 36 months in the medium- and the high-risk group. Thus, clinical improvement was evident in 46.8% of low-risk patients, in 34.8% of medium-risk patients and in 33.3% of high-risk patients (P=0.13) at 36 months.
View larger version (23K):
[in this window]
[in a new window]
|
Fig. 2. Graph showing changes (±S.D.) in the 15D score during the study intervals among 36-month survivors with complete data (263 patients). P-values are according to the Kruskal–Wallis test. The differences between the study groups were significant also according to the repeated measure test (P=0.001).
|
|
The ROC curve analysis showed that neither the additive EuroSCORE (area under the curve [AUC]: 0.490, P=0.78 and AUC: 0.534, P=0.34, respectively) nor the logistic EuroSCORE (AUC: 0.491, P=0.81 and AUC: 0.526, P=0.47, respectively) were predictors of clinically important increase of the 15D score at 6 and 18 months. Both additive (AUC: 0.582, P=0.024) and logistic EuroSCORE (AUC: 0.575, P=0.039) were predictors of a clinically important increase of 15D score at 36 months. However, the AUCs were far from being optimal.
The best cut-off value of the additive EuroSCORE for prediction of a clinically significant improvement of the 15D score was three at the 36-month follow-up. Among patients with a EuroSCORE from 0 to 3, the rate of clinically significant improvement of the 15D score was 46.7%, whereas it was 30.1% among those with an additive EuroSCORE 3 (P=0.006, sensitivity 67.3%, specificity 50.3%, accuracy 57.0%). This cut-off did not predict clinically significant improvement of the 15D score either at 6 months (P=0.83) or 18 months (P=0.52). Fig. 3 shows the pattern of change in the 15D scores in patients with additive EuroSCORE from 0 to 3 and those with an additive EuroSCORE from 4 to 14.
View larger version (19K):
[in this window]
[in a new window]
|
Fig. 3. Graph showing changes (±S.D.) in 15D score during the study intervals among 36-month survivors with complete data (263 patients) with an additive EuroSCORE from 0 to 3 vs. those with a EuroSCORE from 4 to 14. P-values are according to the Mann–Whitney test. The differences between the study groups were significant also according to the repeated measure test (P<0.0001).
|
|
|
4. Discussion
|
|---|
EuroSCORE has been shown to provide a relevant estimate for both short and late outcome after CABG, prolonged length of stay and specific postoperative complications such as renal failure, septic complications and respiratory failure, as well as costs of cardiac surgery [14]. The additive version has been followed by logistic risk model, which may better estimate the risk of mortality of high-risk patients [2].
Earlier reports estimating HRQoL have demonstrated short-term and long-term improvement after CABG both in male and female patients. The most significant exception is for elderly patients, aged over 75 years [11]. However, there are no reports on the discriminatory ability of a preoperative risk stratification model to predict HRQoL after CABG.
In the present study, EuroSCORE predicted longer ICU stay, longer total hospitalization, more complications and poorer long-term survival in high-risk patients paralleling with previous findings. In addition, both additive and logistic EuroSCORE correlated significantly with the 15D score and thereby with the HRQoL during the whole observation time of 36 months.
Patients with a low additive risk had significantly improved HRQoL during the first 6 months after the operation and the improvement lasted well into the observation period. The finding may have been predictable because low-risk patients are relatively young and generally have good preserved left ventricular function and little co-morbidity. Extracardiac arteriopathy, renal failure and depressed left ventricular ejection fraction have been shown to be predictors of long-term outcome in patients with CAD. Co-morbidity like this, together with the ageing process, is likely to be responsible for the lack of significant increase in the HRQoL of high-risk patients later in the follow-up, as herein has been observed.
A significant difference was observed in the HRQoL between low-risk and high-risk patients before the surgery. The difference increased during follow-up although HRQoL initially improved even among high-risk patients. The most important mutual nominator here is age, which has quite strong significance to the EuroSCORE risk but also has been shown to have impact on impaired HRQoL in older ages after CABG [11]. CABG does give improved value on the HRQoL even for high-scoring patients, but for a shorter time than for low-scoring patients.
An important question is how to interpret the minimum clinically or practically important or significant change in the used measure to be such that people can feel the difference in the HRQoL. For the 15D measure a score change of 0.03 has observed to be such. Against this background an increase in the 15D score – and thereby in the HRQoL – which was detected in half of the patients at six months and in one-third of patients at 36 months, may be acceptable. There is still an area between –0.03 and +0.03 change in the score, in which either improvement or impairment may have taken place on some important dimensions for individual patients but the overall score does not valuate the change. However, an improvement on at least one or more dimensions, which are related to healing or physical performance, may have been important for a single patient although the total score did not evidence a significant change. A decreasing trend of the 15D score in high-risk patients later along the postoperative course may mostly depend on more frequent co-morbidity and on normal ageing process.
In the present study we also evaluated separately both the additive and logistic EuroSCORE in predicting HRQoL and observed that both were predictors of clinically important increase of 15D score at 36 months, although the sensitivity and specificity of the score test was not optimal. Our study showed that a significant long-term improvement in the HRQoL is expected in patients with an additive EuroSCORE  3 as the best cut-off value in this scoring system. Practically the finding signifies that male patients under 75 years and female patients under 70 years, with good LVEF and without other co-morbidity, might obtain the best prospect for better HRQoL as related to a significant improvement of the 15D score. A forthcoming study with a larger patient population is still required to assess the possible difference between a disease specific and a non-disease specific measure in predicting quality of life of CABG patients on the basis of risk scoring like EuroSCORE.
The present study was carried out in a single regional centre with a quite low volume of annual CABG procedures. The study was prospective but as the sample was collected over quite a long period of time it was not totally consecutive in respect to the whole cohort of CABG patients operated on during the period. However, the recruitment of the patients took place before coronary angiography and treatment was decided on after the invasive examination. Thus, the arrangement of the study plan may reduce the possible selection bias and its impact on the study outcome. The material reflects mostly elective surgery for CAD and its results should be extended with caution to the general population of patients undergoing CABG. On the other hand, the participation of the survivors in the study achieved a high level and drop-outs were few, which gives strength to the study and its conclusions.
On the basis of these results, we conclude that EuroSCORE, beyond the prediction of postoperative survival, also predicts long-term HRQoL after CABG. Patients with an additive EuroSCORE 3 are more likely to experience a significant increase in HRQoL three years after CABG.
|
References
|
|---|
- Nashef SAM, Roques F, Michel P, Gauducheau E, Lemeshow S, Salamon R, the EuroSCORE Study Group. European System for Cardiac Operative Risk Evaluation (EuroSCORE). Eur J Cardiothorac Surg 1999;16:9–13.[Abstract/Free Full Text]
- Roques S, Michel P, Goldstone AR, Nashef SA. The logistic EuroSCORE. Eur Heart J 2003;24:881–882.[CrossRef][Medline]
- Geissler HJ, Holzl P, Marohl S, Kuhn-Regnier F, Mehlhorn U, Sudkamp M, de Vivie ER. Risk stratification in heart surgery: comparison of six score systems. Eur J Cardiothorac Surg 2000;17:400–406.[Abstract/Free Full Text]
- Toumpoulis IK, Anagnostopoulos CE, De Rose JJ, Swistel DG. European system for cardiac risk evaluation predicts long-term survival in patients with coronary artery bypass grafting. Eur J Cardiothorac Surg 2004;25:51–58.[Abstract/Free Full Text]
- Biancari F, Kangasniemi O-P, Luukkonen J, Vuorisalo S, Satta J, Pokela R, Juvonen T. EuroSCORE predicts immediate and late outcome after coronary artery bypass surgery. Ann Thorac Surg 2006;82:57–61.[Abstract/Free Full Text]
- Nilsson J, Algotsson L, Höglund P, Luhrs C, Brandt J. EuroSCORE predicts intensive care unit stay and costs of open heart surgery. Ann Thorac Surg 2004;78:1528–1534.[Abstract/Free Full Text]
- van Domburg RT, Takkenberg JJ, van Herwerden LA, Venema AC, Bogers AJ. Short-term and 5-year outcome after primary isolated coronary artery bypass graft surgery: results of risk stratification in a bilocation center. Eur J Cardiothorac Surg 2002;21:733–740.[Abstract/Free Full Text]
- Toumpoulis IK, Anagnostopoulos CE, Swistel DG, De Rose JJ Jr. Does EuroSCORE predict length of stay and specific postoperative complications after cardiac surgery? Eur J Cardiothorac Surg 2005;27:128–133.[Abstract/Free Full Text]
- Sintonen H, Pekurinen M. A generic15 dimensional measure of health-related quality of life (15D). J Soc Med 1989;26:85–96.
- Kattainen E, Sintonen H, Kettunen R, Meriläinen P. Health-related quality of life of coronary artery bypass grafting and percutaneous transluminal coronary artery angioplasty patients: 1-year follow-up. Int J Technol Assess Health Care 2005;21:172–179.[Medline]
- Loponen P, Luther M, Wistbacka J-O, Korpilahti K, Laurikka J, Sintonen H, Huhtala H, Tarkka MR. Quality of life during 18 months after coronary artery bypass grafting. Eur J Cardiothorac Surg 2007;32:77–82.[Abstract/Free Full Text]
- Sintonen H. Outcome measurements in acid-related diseases. PharmacoEconomics 1994;5:17–26.
- Sintonen H. The 15D instrument of health-related quality of life: properties and applications. Ann Med 2001;33:328–335.[Medline]
- Pinna PP, Bobbio M, Colangelo S, Veglia F, Marras R, Diena M. Can EuroSCORE predict direct costs of cardiac surgery. Eur J Cardiothorac Surg 2003;23:595–598.[Abstract/Free Full Text]
Related Article
-
eComment: Even the elderly post-CABG patients have a better HRQoL postoperatively
- Efstratios Apostolakis, Anastasios Merkouris, and Ioanna Koniari
Interactive CardioVascular and Thoracic Surgery 2008 7: 568.
[Full Text]
[PDF]
This article has been cited by other articles:
|
|
|
|
 
E. Apostolakis, A. Merkouris, and I. Koniari
eComment: Even the elderly post-CABG patients have a better HRQoL postoperatively
Interactive CardioVascular and Thoracic Surgery,
August 1, 2008;
7(4):
568 - 568.
[Full Text]
[PDF]
|
|
|
|
|
Top
Abstract
1. Introduction
