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* From the Departments of Anesthesiology (Dr. Engoren), Cardiovascular Nursing (Ms. Steckel and Ms. Neihardt), and Research (Ms. Fenn-Buderer), St. Vincent Mercy Medical Center, Toledo, OH; and the Division of Acute, Critical, and Long-Term Care (Dr. Arslanian-Engoren), School of Nursing, University of Michigan, Ann Arbor, MI.
Correspondence to: Milo Engoren, MD, FCCP, Department of Anesthesiology, St. Vincent Mercy Medical Center, 2213 Cherry St, Toledo, OH 43608; e-mail: engoren{at}pol.net
| Abstract |
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Design: Observational case control study. Retrospective analysis of hospital cost and outcome. Prospective analysis of functional status at 1 to 2 years.
Patients: One hundred three consecutive octogenarians and 103 randomly selected septuagenarians who underwent cardiac surgery.
Setting: A university-affiliated tertiary care center.
Measurements and results: Compared to septuagenarians, octogenarians were more likely to be widowed (p
0.001) and to have had preoperative strokes (p
0.05) but were less likely to have diabetes mellitus (p
0.001). They were less likely to have undergone mitral valve surgery (p
0.01) but were more likely to have undergone coronary artery bypass graft surgery without cardiopulmonary bypass (p
0.001). The hospital mortality rate was 6% in the younger group and 9% in the older group (odds ratio, 1.5; 95% confidence interval [CI], 0.5 to 4.5; p > 0.05). In patients undergoing isolated CABG, the mortality rate was 1.4% in the septuagenarians and 8.2% in the octogenarians (odds ratio, 6.2; 95% CI, 0.7 to 52.7; p = 0.12). Despite similar ICU, postoperative, and total lengths of stay, the median hospital direct variable cost was 35% higher for the octogenarians. At late follow-up, octogenarians had lower levels of physical functioning and general health but otherwise had levels of function that were similar to those of septuagenarians.
Conclusion: Cardiac surgery can be performed in the elderly with good hospital and late functional results, but at a higher hospital cost than that for younger patients.
Key Words: cardiac surgery coronary artery bypass grafting direct variable cost functional outcome octogenarians septuagenarians survival
| Introduction |
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80 years. Other westernized countries, including Japan, also have large and increasing elderly segments of their populations. Forty percent of these elderly persons have symptomatic cardiac disease.1
2
Surgery, a well-accepted means of increasing survival and improving quality of life in patients < 70 years of age, is becoming more common in septuagenarians and even octogenarians. However, perceptions by elderly patients, their families, and their physicians that they may have lower functional reserve and more comorbidities than younger patients, which are more likely to lead to complications or death, may make cardiologists and cardiac surgeons hesitant to offer elderly patients life-saving or symptom-resolving cardiac surgery. Yet, few studies exist to show the benefits, risks, and costs of cardiac surgery in octogenarians. Previous studies3
4
5
6
have had small populations, are from the 1980s (improvements in perioperative techniques and care may make these results obsolete), or have not evaluated functional outcomes and costs in the same population. Therefore, the purpose of this study was twofold, as follows: (1) to determine hospital outcomes and costs; and (2) to measure functional outcomes at 1 to 2 years in octogenarians compared to septuagenarians following cardiac surgery. | Materials and Methods |
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2.0 mg/dL if the preoperative creatinine level was normal, or a rise in the creatinine level of
1.0 mg/dL if the preoperative creatinine level was
1.5 mg/dL); hemodialysis; prolonged mechanical ventilation (defined as a requirement for mechanical ventilation beyond 7 AM the day after surgery; atrial fibrillation; hospital outcome; and discharge to home, extended care facility (ECF), transitional care unit (TCU), rehabilitation hospital, or other location. Direct variable cost was obtained from the hospitals accounting department. All billed items and their associated costs were assigned to 1 of the following 14 cost categories: preop (all costs incurred before the morning of surgery); anesthesia (costs of anesthetics, equipment, and disposables used by the anesthesiologist); perfusion (costs of cardiopulmonary bypass equipment, cardioplegia, and disposables used by the perfusionist); surgery (all other costs related to the use of the operating room, surgical equipment, and disposables used by the surgeon); cardiovascular ICU (CVICU) [costs related to nursing, equipment, and room in the cardiovascular ICU]; postop room (costs related to nursing, equipment, and room on the stepdown unit); respiratory (costs related to respiratory equipment, treatments, and therapist time); laboratory, blood bank (blood typing and transfusions); Ekg & vasc lab (electrocardiograms and noninvasive vascular studies); radiology, pharmacy, therapies (physical, occupational, and speech therapy); and supplies.
Death was determined from the Social Security Death Index, obituaries in The Toledo Blade, and hospital records. Three trained registered nurses attempted to contact all survivors. If the survivor gave oral informed consent, the 36-item short form (SF-36) questionnaire7 was administered during the same telephone conversation.
Statistical Analysis
In addition to analyzing all patients who had undergone cardiac surgery, patients who had undergone only CABG surgery (ie, CABG-only group) were compared. Univariate comparisons between groups were made using
2 tests for categoric characteristics or Mann-Whitney-Wilcoxon tests for continuous characteristics. Linear regression analysis using forward, backward, and stepwise selection was used to explain the variability in direct variable cost.
| Results |
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0.001), while septuagenarians were more likely to be married (p < 0.01). Octogenarians were more likely to have had preoperative strokes (p = 0.05) but were less likely to have diabetes mellitus (p < 0.001). Other comorbidities were distributed similarly. Octogenarians were less likely to have undergone mitral valve surgery (p = 0.01) but were more likely to have their CABGs performed without cardiopulmonary bypass (p < 0.001). Postoperative complications were similar between the two groups (Table 2
). The hospital mortality rate was 5.8% in the younger group and 8.7% in the older group (relative risk [RR], 1.5; 95% confidence interval [CI], 0.5 to 4.5; p > 0.05). Of the nine octogenarians who died, two died of cardiac failure on the day of surgery. Four of the remaining seven octogenarians required re-exploration surgery for bleeding, one had a CVA, two had encephalopathy, and six had sufficient renal dysfunction to undergo dialysis. Of the six septuagenarians who died, one died of heart failure on the first postoperative day. Two of the remaining five septuagenarians required re-exploration surgery for bleeding, three had encephalopathy, and four required hemodialysis. In patients undergoing isolated CABGs, the mortality rate was 1.4% among septuagenarians and 8.2% among octogenarians (RR, 6.2; 95% CI, 0.7 to 52.7; p = 0.12). Older patients were less likely to be discharged from the hospital directly to home (RR, 0.3; 95% CI, 0.17 to 0.6; p
0.01) and were more likely to be discharged to a TCU or ECF (RR, 3.0; 95% CI, 1.7 to 5.6; p
0.01). Despite similar ICU, postoperative, and total lengths of stays, the median hospital cost was 35% higher for the octogenarians (Table 3
). By linear regression, higher cost was associated with being an octogenarian, having re-exploration surgery for bleeding, and longer hospital length of stay. Having the surgery performed without cardiopulmonary bypass was associated with a lower cost (Table 4
).
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The interviews showed that both groups had excellent social functioning and role-emotional outcomes (Table 5 ). The values for the other SF-36 scales were similar between the two groups except that the octogenarians had lower levels of physical functioning and general health.
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| Discussion |
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80 years and had undergone isolated CABG surgery between 1987 and 1990. The 1-year mortality rate for those patients was 19%, compared to 12% in this study. Our lower rate may be due to differences in patient selection or to improvements in operative techniques and perioperative care over the last decade. Many factors have been found to be associated with increased mortality among the octogenarians, particularly emergency surgery, complexity of the surgery, and the presence of comorbidities.5 10 11 Whether due to different criteria for patient selection or to improvements in stabilization in the catheterization laboratory, we, unlike Avery et al,5 had few emergency patients with severe hemodynamic instability. Where Glower et al11 noted an in-hospital mortality rate of 23% in octogenarian patients with any comorbidities, compared to 7% in patients without any comorbidities, we found that almost all of our octogenarian patients (92.2%) had at least one comorbidity. However, this high rate of comorbidities is similar to those cited in other studies.3 5
We found that the older group was more likely to have had their CABG surgery performed without cardiopulmonary bypass (ie, off-pump surgery). While firm data are lacking, off-pump surgery is felt to cause less postoperative neurologic and renal dysfunction.12 This may have contributed to the similar rates of cerebral and renal dysfunction in our two groups. The occurrence of complications predicted a worse outcome, with dialysis being a prominent marker of hospital death. The survival rate among patients initiating dialysis was 30% among octogenarians and 57% among septuagenarians (p > 0.05). This finding is similar to patients in a general ICU. Octogenarians initiating hemodialysis in the ICU had a survival rate (33.3%) that was similar to that of nonoctogenarians (36.4%).13
Peterson et al9 attributed the 20% higher cost for octogenarian patients to their longer average length of hospital stay (3.9 days). Avery et al5 noted an average 26.8% higher cost for their octogenarian patients, which was explained on the basis of a 37% longer average hospital length of stay and a higher intensity of illness. In contrast, our study found identical median ICU and postoperative lengths of stays and similar total lengths of stays between the younger and older groups. Despite this, the median costs were 35% higher in the older group. While costs were hundreds of dollars higher in the octogenarian group for the high-cost categories of surgery, perfusion, and CVICU stay, these did not reach statistical significance, probably because of inadequate power to detect subgroup differences.
Previous studies have found mean postoperative lengths of stays of 10 to 16 days5 9 11 14 and mean total hospital lengths of stays of 22 days3 for elderly patients, which are considerably longer than the median postoperative length of stay of 6 days and the total hospital length of stay of 9 days in this study. This probably relates to our fast-track cardiac program,15 the availability of a TCU contiguous to the hospital, and nearby ECFs. Only 21% of our octogenarians were discharged to home, which is significantly less than the rate for the septuagenarians (47%). The higher rate of octogenarians being discharged to places other than home was partially due to octogenarians being less likely to be married. But, even comparing married octogenarians to married septuagenarians, married octogenarians were still less likely to be discharged to home (33% vs 51%, respectively; p < 0.05). Further evaluation is needed to determine whether this is related to spousal disability or other reasons. It was also significantly less than the 64% reported elsewhere.3 A higher rate of admission to the TCU or ECFs may be the tradeoff for a short hospital length of stay.
We found that other than octogenarians having lower levels of physical functioning and general health, octogenarians and septuagenarians had similar functional outcomes. The octogenarians in our study had similar scores or trends to better scores than the general population that was
75 years old,7
but they had lower scores than Canadian octogenarians after cardiac surgery.3
Fruitman et al3
administered the SF-36 to 99 of 103 octogenarian survivors at 15.7 ± 6.9 months after their cardiac surgery in Halifax, NS, Canada. They found consistently higher scores for five of the eight scales than we found (p < 0.01 for Role-Physical, Bodily Pain, General Health Perceptions, and Mental Health; p < 0.05 for Vitality; and p > 0.05 for Physical Functioning, Social Functioning, and Role-Emotional). Whether this is due to different patient characteristics, different versions of the SF-36, or differences in the social services, medical care, and prescription drug benefits between Canada and the United States cannot be determined.
A limitation of this study is that it was conducted at only one institution. Other hospitals may have different experiences. A multicenter study might also provide sufficient statistical power to detect a difference in mortality. However, the population is similar in size to those in most other studies evaluating cardiac surgery in the elderly.3 14 16 17 18 19 Given the hospital mortality rates that we found (septuagenarians, 5.8%; octogenarians, 8.7%), it would take approximately 1,250 patients in each group to find a statistically significant difference, with a type I error of 0.05% and 80% power. The moderate number of patients studied also precludes us from developing a risk model for predicting death, complications, cost, or functional outcome.
Another limitation is that one fourth of the survivors did not consent to be interviewed or could not be located. Given that these 46 patients were slightly older, were more likely to have renal dysfunction, were more likely to have undergone aortic valve surgery, were more likely to develop atrial fibrillation, and were more likely to cost more, they may not have as good functional outcomes as those who participated in the interview.
| Conclusion |
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| Footnotes |
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Received for publication September 28, 2001. Accepted for publication April 23, 2002.
| References |
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