(Circulation. 1995;92:85-91.)
© 1995 American Heart Association, Inc.
Articles |
Outcomes of Coronary Artery Bypass Graft Surgery in 24 461 Patients Aged 80 Years or Older
From the Division of Cardiology, Department of Medicine, and the Division of Biometry, Department of Community and Family Medicine, Duke University Medical Center, Durham, NC.
Correspondence to Eric D. Peterson, MD, MPH, Box 3236, Duke University Medical Center, Durham, NC 27708-3236.
 |
Abstract |
|---|
 Top Abstract IntroductionMethods Results Discussion References |
|---|
Background Coronary artery bypass graft surgery is increasingly common in patients of age
80 years.
Single-institution reviews have cited a wide range of mortality
results after bypass surgery in this age group, in part because of
limited sample sizes. Using claims data, we examined recent national
trends in the use and outcomes of bypass surgery in the very
elderly.
Methods and Results From an examination of Medicare data from
1987 through 1990, we identified 24 461 patients of age 80 years who
underwent bypass surgery. We compared surgical outcomes in these
patients with those in Medicare patients of age 65 to 70 years. We
found that the national use of bypass surgery in patients of age 80
years increased 67% between 1987 and 1990. Compared with patients of
age 65 to 70 years, the very elderly had significantly longer
postoperative hospital stays (mean, 14.3 versus 10.4 days), higher
charges (mean, $48 200 versus $38 000), and greater costs (mean,
$27 200 versus $21 700). In-hospital (11.5% versus 4.4%),
1-year (19.3% versus 7.9%), and 3-year mortality rates (28.8% versus
13.1%) after bypass surgery were also significantly higher in patients
of age 80 years compared with younger patients. Although their
initial surgical risk was high, octogenarians who underwent bypass
surgery had a long-term survival rate similar to that of the
general US octogenarian population.
Conclusions The use of bypass surgery in patients of age 80
years is increasing. These very elderly patients face high surgical
risks and accumulate significant hospital expenses. Further research is
indicated to determine whether the long-term benefits from bypass
surgery in the very elderly outweigh the increased procedural risks.
Key Words: aging • survival • cardiopulmonary bypass • revascularization
|
Introduction |
|---|
|
TopAbstractIntroductionMethods Results Discussion References |
|---|
In the United States in 1990, there were 6.9 million persons of age
80 years, and there will be nearly 25
million by 2050. Currently, 1 in 35 Americans is of age 80 years; by
2050, this proportion will be 1 in 12.1 Life expectancy at
age 80 in the United States exceeds 8 years; however, surveys suggest
that more than 25% of octogenarians have significant functional
limitations secondary to cardiovascular
disease.2 3 Many of these patients have disease
refractory
to medical therapy and may be potential candidates for coronary
artery bypass graft surgery (CABG).
The results of CABG in patients of age 80 years have been reported
only in single-institution case
series.4 5 6 7 8 9 10 11 12 13 14 15
These
reviews have generally reported higher surgical risk in octogenarians
compared with younger patients. In-hospital mortality estimates for
patients of age 80 years undergoing CABG, however, have ranged from
5.6% to almost 25% (Table 1
). This variation in
outcome results in part from differences in the mix of surgical
patients at these institutions and from random variation in estimates
due to the limited sample size at any single institution. Moreover,
although previous studies have reported patient outcomes, they have not
defined the resource costs associated with performing bypass surgery in
patients of age 80 years.
|
Our study examined the use and outcomes of bypass surgery in patients
of age 80 years within the national Medicare database. Because
Medicare provides insurance for the vast majority of America's
elderly, these results are representative of the
national outcomes of bypass surgery in the very elderly. To reflect
recent cardiovascular practice, this study also
included surgical cases performed from 1987 through 1990. Outcomes
examined include postoperative length of stay, in-patient charges
and costs, and mortality for up to 3 years after bypass surgery. Also,
we compared the outcomes of bypass surgery in patients of age 80
years with those in Medicare patients of age 65 to 70 years. Finally,
given the anticipated changes in US age demographics, we projected
how the use of bypass surgery in octogenarians may have an impact on
the nation's healthcare resource expenditures.
|
Methods |
|---|
|
TopAbstractIntroductionMethods Results Discussion References |
|---|
Data Sources
Data were obtained from the Medicare Provider Analysis and Review file provided by the Health Care Financing Administration for Medicare Part A enrollees who received coronary artery bypass graft surgery from 1987 through 1990. This file contains demographic and limited clinical information on all hospitalizations that are billed to Medicare, including the enrollee's health insurance claim number, age, sex, race, discharge status (including death), and up to five discharge diagnoses and three procedures as identified by International Classification of Diseases (ICD-9-CM) codes.16 In-patient hospital and department charges exclusive of professional fees were also obtained from the Medicare records. Departmental cost-to-charge ratios were taken from the Health Care Resource Information Systems (HCRIS) computer files (1987 through 1991). Mortality data through September 1993 came from Medicare records and date-of-death files. Using individual patient identifiers, we linked subsequent hospital admissions and procedures to form a longitudinal record of a patient's hospital care and costs for 1987 through 1990.
Patient Populations
The study population consisted of all
patients of age 80 years
in the Medicare files who underwent bypass surgery (ICD-9-CM codes
36.10 through 36.19) between 1987 and 1990. For the purposes of this
report and consistent with previous literature, the term
"octogenarian" was used in reference to patients of age 80
years. As noted in our results, patients between the ages of 80 and 89
years constituted 99% of our cohort. We contrasted surgical outcomes
in this age group with those in a cohort of younger Medicare patients,
of age 65 to 70 years, who received bypass surgery during the same time
period. Within the timeframe of study, we could be sure that no patient
was represented in both cohorts. Patients who underwent
multiple bypass surgery procedures during the study period were
included only once, identified by their initial bypass surgery.
We
initially identified 202 488 patients of age 80 years or of age
65 to 70 years who received bypass surgery between 1987 and 1990.
Patients were excluded for any of three reasons, with some patients
meeting more than one of the following exclusion criteria:
Medicare eligibility and follow-up data. We excluded patients who received Medicare benefits as part of the Railroad Retirement Board (1.4%) and patients who had end-stage renal disease (0.2%) as a reason for Medicare eligibility. We excluded patients who were enrolled in health maintenance organizations because Medicare does not have continuous, reliable data on these patients (4.0%). Patients who were admitted to non-US hospitals or federal hospitals were also excluded for this reason (0.5%).
Failed coronary angioplasty. We excluded patients who received percutaneous transluminal coronary angioplasty (ICD-9-CM code 36.01, 36.02, or 36.05) during the same hospitalization as the bypass surgery to avoid attributing mortality from failed angioplasty cases to bypass surgery outcomes (2.4%).
Combined open-heart procedures. We wished to focus on outcomes after isolated bypass surgery in the elderly. Patients were therefore excluded who underwent concomitant cardiac valve replacement (ICD-9-CM codes 35.2 or 35.3), papillary muscle or chordae tendineae repair (ICD-9-CM codes 35.31 or 35.32), ventricular septal repair (ICD-9-CM 35.53, 35.62, or 35.72), and/or implantation of an automatic cardioverter-defibrillator system (ICD-9-CM 37.94 or 35.95) (7.2%).
Statistical Analysis
We determined the frequencies of
demographic and clinical
characteristics for the 65- to 70- year-old and 80-year-old
bypass surgery cohorts. Patients were considered to have been admitted
for an acute myocardial infarction if their primary diagnosis was
ICD-9-CM code 410.xx and their total length of stay was 3 days (after
linking interhospital transfers) for patients discharged
alive.17 The frequencies of coded comorbid diseases (eg,
congestive heart failure or pulmonary disease) were determined
with previously developed ICD-9-CM mapping strategies applied to
discharge abstract information.18 19
Procedure utilization rates were calculated by dividing the number of initial procedures performed during a given year by the number of Medicare-eligible patients for that year. The denominators for these rates were derived from Medicare's enrollment database after applying patient exclusions as previously listed. Total and postoperative lengths of stay were calculated from admission date and procedure date, respectively, to date of discharge.
To estimate the cost of the hospital stay for bypass surgery, we converted hospital charges, exclusive of professional fees, that were billed to Medicare to costs with the use of department cost-to-charge ratios available from national Health Care Resource Information Systems files. The total adjusted cost for each admission was the sum of the adjusted department costs. Costs were then aggregated into inpatient episodes, which were defined as hospitalizations preceding or following the bypass surgery hospitalization by 1 day. Finally, all charge and cost data were standardized to 1990 dollars by use of the Consumer Price Index for hospital services.20 It should be noted that although no gold standard exists for estimating the actual "cost" for a given procedure, cost-to-charge ratios have been used in previous investigations21 22 and in one study yielded equal bypass surgery cost estimates when compared with a detailed microcost accounting system (Transition System 1).23
Survival after
bypass surgery was calculated from the procedure date
forward. The procedure date was missing in fewer than 0.1% of the
records, and the admission date was substituted in these cases.
Because we had complete survival follow-up without censoring
through September 1993, we calculated unadjusted Kaplan-Meier survival
rates24 up to 3 years after bypass surgery for patients of
age 65 to 70 years and for those of age 80 years. Long-term
survival rates in octogenarians undergoing bypass surgery were also
compared with survival estimates for US citizens of similar ages, which
were available from vital statistics data prepared by the US Bureau of
the Census.2
Independent clinical predictors of 30-day mortality in octogenarians receiving bypass surgery were estimated with a multivariate logistic regression model. Similarly, independent predictors of 3-year mortality were estimated with a Cox survival model.25 Variables entered into these models were selected based on their univariate association with bypass surgery mortality (P<.01) or their clinical relevance. The final regression models simultaneously adjusted for patient age, race, sex, and presence of preoperative acute myocardial infarction, congestive heart failure, peripheral vascular disease, cerebral vascular disease, chronic renal failure, pulmonary disease, and diabetes mellitus with sequelae. From the variable parameter estimates and standard errors produced by these models, we calculated odds ratios (ORs) for mortality and the 95% confidence intervals surrounding these estimates for each clinical predictor.
|
Results |
|---|
|
TopAbstractIntroductionMethods Results Discussion References |
|---|
Demographics
Between 1987 and 1990, we identified 24 461 patients of age
80
years covered by Medicare who met study criteria and underwent
coronary artery bypass graft surgery. A total of 83% of these
patients were of age 80 to 85 years, 13% were of age 86 to 90 years,
and 1% were of age 90 years. Baseline characteristics for these very
elderly patients were compared with those for patients of age 65 to 70
years who received bypass surgery (Table 2).
Octogenarians were significantly more likely to be female and white and
to have been admitted for an acute myocardial infarction before
receiving bypass surgery. Octogenarians receiving bypass surgery were
also more likely to be coded as having congestive heart failure or
cerebral vascular disease but less likely to have pulmonary
disease or diabetes mellitus than were patients of age 65 to 70
years.
|
We also examined temporal trends in the use of bypass surgery in these two age categories. The national rate of bypass surgery performed per year in octogenarians increased by 67% during the 4 years of this study, from 7.2 per 10 000 in 1987 to 12.0 per 10 000 in 1990. This rate significantly exceeded that of patients of age 65 to 70 years, whose rate increased by 10.3% during this same time period, from 38.1 per 10 000 to 42.1 per 10 000.
Mortality After Bypass Surgery
Unadjusted survival rates
after bypass surgery in patients of age
80 compared with patients of age 65 to 70 years are given in Table
3. Overall 30-day, in-hospital, 1-year, and 3-year
mortality rates for octogenarians were 10.5%, 11.5%, 19.2%, and
28.8%, respectively. These values were more than twice as high as
those in patients of age 65 to 70 years: 4.3%, 4.4%, 7.9%, and
13.1%, respectively.
|
Mortality rates are generally higher in
octogenarians than in younger
patients regardless of whether they receive bypass surgery. To provide
a perspective for evaluating long-term outcomes after bypass
surgery in patients of 80 years, we compared 3-year mortality rates
in these patients with mortality estimates for the general US
octogenarian population (Fig 1). Although octogenarians
receiving bypass surgery face high procedural risks, their 3-year
mortality rate after the procedure was nearly equal to that of
similarly aged US citizens: 28.8% versus 26.6%.
|
Independent clinical
predictors of 30-day and 3-year mortality after
bypass surgery in octogenarians are given in Table 4.
Age was a significant predictor of both 30-day and 3-year mortality.
For example, an 85-year-old patient undergoing bypass surgery would
have nearly 40% higher odds for mortality at 30 days than a similar
patient of age 80 years. Women and nonwhite patients had slightly worse
procedural and long-term outcomes than did men and white patients.
Measures of acute coronary disease, such as acute myocardial
infarction before bypass surgery and congestive heart failure, also
predicted higher procedural and long-term mortality rates. Finally,
comorbid illnesses such as peripheral vascular disease and
chronic renal disease were highly predictive of 30-day and 3-year
mortality.
|
Resource Use
Postoperative hospital stays after bypass
surgery were
significantly longer in octogenarians than in patients of age 65 to 70
years (mean, 14.2 days [25th to 75th percentile, 8 to 15 days]
versus
10.8 days [7 to 11 days], respectively; Table 5).
These longer stays by the very elderly were reflected in increased
total hospital charges (exclusive of professional fees) for the bypass
surgery admissions in octogenarians (mean charges, $48 200 [$28 000
to $53 000] versus $38 000 [$24 000 to $42 000] for patients of
age 65 to 70 years). Calculated hospital costs for the bypass surgery
were also higher in those of 80 years (mean cost, $27 200 [$17 000
to $30 000] versus $21 700 [$14 000 to $23 000]).
|
Longer postoperative length of stay by the very elderly was only a partial explanation for their higher relative costs. The intensity of medical services delivered per day was also increased in octogenarians after bypass surgery, as reflected in their higher cost per hospital day ($1567 versus $1472 per day). Finally, although the mean values for hospital stay, charge, and cost data were skewed in both age strata by high outlier patients with multiple postoperative complications, the median values for these resource measures remained 38%, 22%, and 21% higher, respectively, in octogenarians than in younger patients.
|
Discussion |
|---|
|
TopAbstractIntroductionMethods Results Discussion References |
|---|
Coronary artery bypass graft surgery in the very elderly is becoming increasingly common. During a 4-year period between 1987 and 1990, the national rate of bypass surgery in patients of age
80
years increased by 67%. Our data demonstrate, however, that the
performance of bypass surgery in the very elderly is associated
with substantially higher short- and long-term mortality rates and
that they consume significantly more healthcare resources per procedure
than do younger patients.
Previous studies have reported that increasing age is a risk factor for
in-hospital and long-term mortality after bypass
surgery.4 26 27 28 29 30
Specific mortality estimates in the very
elderly, however, have varied widely, as noted in Table 1
.
Given that
procedural mortality appears to be declining in the
elderly,31 part of these differences in surgical outcome
may be explained by the inclusion of cases from more than 15 years ago.
Also, these institutional reviews contained patients with varying
severity of illness and comorbidity. Because of the relatively small
sample sizes available in these case series, minor differences in
patient risk may have had large impacts on overall procedural mortality
rates. Finally, the limited number of patients in these reports result
in wide confidence intervals surrounding the estimates of procedural
mortality rates. Thus, the "play of statistical chance" may also
have contributed significantly to the variation in reported
estimates.
By combining the results from published reports, one can examine an average or composite mortality estimate from these series. Composite estimates of bypass surgery mortality outcomes based on 1035 cases in the literature are similar to our results based on Medicare patients (in-hospital mortality, 10.4% versus 11.4%; 1-year mortality, 17.5% versus 19.3%; 3-year mortality, 28.7% versus 28.8%, respectively). The slightly lower mortality results from the published case series may reflect the higher efficacy of bypass surgery performed on octogenarians at major academic centers and/or the impact of reporting bias on published mortality estimates.
Predictors of Mortality
Literature regarding clinical
predictors of mortality after bypass
surgery in the very elderly has been extremely limited. The largest
reported clinical series from the Mayo Clinic (159 patients) was able
to identify only depressed left ventricular function as an
independent predictor of bypass surgery mortality in
octogenarians.7 Weintraub and colleagues9
also noted that the combination of left ventricular
dysfunction and diabetes mellitus identified octogenarians at higher
risk for in-hospital and long-term mortality. Congestive heart
failure and the urgency of surgery have also been predictive of
surgical mortality.11 13 Although other clinical
factors
such as peripheral vascular, pulmonary, and renal
disease appear to increase surgical risk in octogenarians in many of
these studies, no series has been large enough to confirm these
trends.
Using national Medicare data, we had access to the results for
more
than 24000 patients from which to identify predictors of short- and
long-term mortality in octogenarians undergoing bypass surgery
(Table 4). We found that increasing age, female sex, and
measures of
disease acuity (preoperative acute myocardial infarction or congestive
heart failure) identified octogenarians with significantly higher
30-day and 3-year mortality rates after bypass surgery. Comorbid
illnesses such as chronic renal disease, peripheral
vascular disease, and cerebral vascular disease also independently
predicted patients with higher 30-day and 3-year mortality rates.
Interestingly, diabetes mellitus and pulmonary disease were not
predictive of 30-day mortality but did predict worse long-term
outcomes.
Given that these mortality prediction models are based on claims data, they must be considered with caution. Claims data have previously been demonstrated to undercode comorbid disease processes.32 33 34 Although the specificity of claims coding for comorbid illness appears high, less severe conditions tend not to be coded.32 This selective undercoding of comorbidity could have led to an overestimate of the predictive power of these conditions. Also, it is often difficult to separate preoperative comorbid illnesses from postoperative complications. For example, the coding of cerebral vascular disease may indicate a previous stroke or a postoperative event. For certain conditions, such as myocardial infarction, we were able to identify preoperative events by identifying only those cases where the principal reason for hospital admission was acute myocardial infarction. Finally, Medicare claims data allow for the coding of no more than five disease processes. This limitation may lead to an undercoding of chronic conditions, such as pulmonary disease, in patients with multiple acute disease processes and complications. Because these patients also have increased mortality rates, this can lead to an apparent, albeit incorrect, assumption that the chronic condition is actually "protective."33 34 Despite these limitations, the predictors of increased surgical risk in octogenarians found in the present study are in general consistent with trends reported in previous smaller institutional series and with clinical expectations. Further confirmation of these findings will be required in large, multicenter clinical studies.
Cost Issues
Previous studies have not examined hospital costs
in octogenarians
undergoing bypass surgery. Compared with patients of age 65 to 70
years, octogenarians had significantly longer mean postprocedural
lengths of stay and higher hospital costs. Although some of this
increased mean expense in octogenarians may be attributable to high
"outlier" patients who have multiple postoperative complications,
the median values for postoperative hospital stays and hospital costs
remained 20% to 40% higher for octogenarians than for younger
patients.
Given the expected growth in the number of US octogenarians
over the
next 50 years, the overall cost of bypass surgery in the very elderly
begins to have major health policy implications. For example, the right
axis of Fig 2 depicts the expected number of bypass surgery
procedures that will be performed in US octogenarians over the next 60
years if we conservatively assume that the "rate" of bypass
surgery (which has been increasing by more than 15% per year) will
remain constant at 1990 levels. Despite this conservative assumption,
given the dramatic demographic shifts in the US population, the number
of bypass surgeries performed can be expected to increase from 8000 per
year in 1990 to more than 30 000 procedures per year by 2050. The left
axis of Fig 2 displays the expected in-hospital costs for these
procedures, again conservatively assuming no temporal changes in the
cost per procedure. By 2050, in-hospital costs for bypass surgery
alone in octogenarians will exceed $1.2 billion (in 1990 dollars).
Because these projections do not include professional fees, the
total cost for these procedures will be substantially higher than these
estimates.
|
Risk Versus Benefit
Multiple randomized clinical trials have
helped define which
patients are most likely to benefit from bypass
surgery.32 33 34 These clinical trials,
however, were not
performed on the very elderly. It is clear from the present study
that expected risks and outcomes from bypass surgery in the "young
elderly," those between 65 and 70 years of age, cannot be
extrapolated to octogenarians. Octogenarians face significantly higher
procedural risk and can be expected to have significantly poorer
long-term outcomes than patients of age 65 to 70 years (see Table
3).
The unanswered question is whether octogenarians incur sufficient benefit from these procedures in terms of symptom relief and improved survival expectations to justify the surgical risk. Unfortunately, information comparing surgical intervention with conservative care in the very elderly with coronary disease is quite limited. In terms of symptom relief, Weintraub and colleagues9 found that 82% of patients with severe baseline angina who were alive at 3-year follow-up remained asymptomatic. Other clinical series have confirmed these findings, demonstrating long-term improvements in functional status and symptom relief with surgical therapy in the very elderly.7 15
Whether bypass surgery improves survival expectations in octogenarians, however, remains unknown. Published randomized trials of bypass surgery versus medical therapy have excluded the very elderly.36 37 Ongoing randomized trials of revascularization therapy have not enrolled sufficient numbers of octogenarians to examine the efficacy of these procedures in this age group.38 39 40 Finally, published nonrandomized comparisons of therapeutic options in octogenarians with coronary disease have been severely limited in size, decreasing the ability of these studies to adjust for baseline patient differences among the various treatment strategies.12 41 42
When a patient and physician discuss options for the optimal therapy in a given clinical situation, they must weigh the risks of the procedure against the long-term risks of foregoing the procedure. In general, those patients at highest risk from their disease process (ie, severe coronary disease and depressed ventricular function), although facing higher surgical risk, stand to benefit the most in terms of long-term survival from surgery.43 Although administrative databases such as the one applied in the present study can supply accurate overall procedural mortality estimates, these data lack important clinical variables, such as left ventricular function and coronary anatomy, necessary for meaningful nonrandomized comparisons of outcomes in octogenarians with coronary disease. Large multicenter clinical databases, such as the ongoing Cooperative Cardiovascular Project, may in the future have a sufficiently large database of elderly patients to address these important issues.44
In conclusion, the present study demonstrated that the use of bypass surgery in octogenarians is expanding rapidly. We also provide patients and physicians with national mortality rates after bypass surgery in the very elderly. These accurate estimates can provide a starting point for the dialogue between physicians and patients faced with the difficult decisions surrounding the treatment of coronary disease in the very elderly. It is clear that with the ongoing demographic changes in the United States, these decisions have growing implications for healthcare resource utilization and national health policy. Decisions concerning these expenditures should, in part, be made more easily with increased knowledge concerning the effectiveness of this intervention in the very elderly in general practice. Further clinical studies are therefore strongly indicated to determine whether the benefits from bypass surgery in the very elderly justify the substantially increased risks.
|
Acknowledgments |
|---|
This work was supported by research grants HS-06503 and HS-05635 from the Agency for Health Care Policy and Research, Rockville, MD; by research grant HL-17670 from the National Heart, Lung, and Blood Institute, Bethesda, MD; and a grant from the Robert Wood Johnson Foundation, Princeton, NJ.
|
References |
|---|
|
TopAbstractIntroductionMethods Results Discussion References |
|---|
1. Specer G. US Bureau of the Census: Projections of the Population of the United States, by Age, Sex, and Race: 1988 to 2080. Washington, DC: US Government Printing Office; 1989. Current Population Reports, Series P-25, No. 1018.
2. National Center for Health Statistics. Vital Statistics of the United States, 1989: Vital Health Statistics: Vol 2. Washington, DC: US Government Printing Office; 1992:11.
3. National Center for Health Statistics. Current Estimates From the National Health Interview Survey, 1989: Vital and Health Statistics Series 10. Washington, DC: US Government Printing Office; 1990. No. 176.
4. Hall RJ, Elayda MA, Gray A, Mathur VS, Garcia E, DeCastro CM, Massumi A, Cooley DA. Coronary artery bypass: long-term follow-up of 22,284 consecutive patients. Circulation. 1983;68(suppl II):II-20-II-26.
5. Edmunds LH, Stephenson LW, Edie RN, Ratcliffe MB. Open-heart surgery in octogenarians. N Engl J Med. 1988;319:131-136. [Abstract]
6. Kowalchuk GJ, Siu SC, McAuliffe LS, Maggs PR, Lewis SM. Coronary artery bypass surgery in octogenarians: early and late results. J Am Coll Cardol. 1990;15:35A. Abstract.
7. Mullany CJ, Darling GE, Pluth JR, Orszulak TA, Schaff HV, Ilstrup DM, Gersh BJ. Early and late results after isolated coronary artery bypass surgery in 159 patients aged 80 years and older. Circulation. 1990;82(suppl IV):IV-229-IV-236.
8. Merrill WH, Stewart JR, Frist WH, Hammon JW, Bender HW. Cardiac surgery in patients age 80 years or older. Ann Surg. 1990;211:772-776. [Medline] [Order article via Infotrieve]
9. Weintraub WS, Clements SD, Ware J, Craver JM, Cohen CL, Jones EL, Guyton RA. Coronary artery surgery in octogenarians. Am J Cardiol. 1991;68:1530-1534. [Medline] [Order article via Infotrieve]
10. Tsai TP, Nessim S, Kass RM, Chaux A, Gray RJ, Khan SS, Blanche C, Utley C, Matloff JM. Morbidity and mortality after coronary artery bypass in octogenarians. Ann Thorac Surg. 1991;51:983-986. [Abstract]
11. Nauheim KS, Dean PA, Fiore AC, McBride LR, Pennington DG, Kaiser GC, Willman VL, Barner HB. Cardiac surgery in the octogenarian. Eur J Cardiothorac Surg. 1990;4:130-135. [Abstract]
12. Mick MJ, Simpfendorfer C, Arnold AZ, Piedmonte M, Lytle BW. Early and late results of coronary angioplasty and bypass in octogenarians. Am J Cardiol. 1991;68:1316-1320. [Medline] [Order article via Infotrieve]
13. Ko W, Krieger KH, Lazenby S, Shin YT, Goldstein M, Lazzaro R, Isom OW. Isolated coronary artery bypass grafting in one hundred consecutive octogenarian patients: a multivariate analysis. J Thorac Cardiovasc Surg. 1991;102:532-538. [Abstract]
14. Braunstein EM, Bajwa TK, Andrei L, Maglio C, Richardson C, Shen YH, Schmidt DH. Early and late outocome of revascularization for unstable angina in octogenarians. J Am Coll Cardol. 1991;17:151A. Abstract.
15. Glower DD, Christopher TD, Milano CA, White WD, Smith LR, Jones RH, Sabiston DC Jr. Performance status and outcome after coronary artery bypass grafting in persons aged 80 to 93 years. Am J Cardiol. 1992;70:567-571. [Medline] [Order article via Infotrieve]
16. International Classification of Diseases, 9th Revision, Clinical Modification. Los Angeles, Calif: Practice Management Information Corp; 1991.
17. State of California, Office of Statewide Planning and Development. Annual Report of the California Hospital Outcomes Project. December 1993.
18. Charlson ME, Pompei P, Ales KL, MacKenzie CR. A new method of classifying prognostic comorbidity in longitudinal studies: development and validation. J Chronic Dis. 1987;40:373-383. [Medline] [Order article via Infotrieve]
19. Romano PS, Roos LL, Jollis JG. Adapting a clinical comorbidity index for use with ICD-9-CM administrative data: differing perspectives. J Clin Epidemiol. 1993;46:1075-1079. [Medline] [Order article via Infotrieve]
20. US Bureau of Labor Statistics. Monthly Labor Review and CPI Detailed Report. January 1992.
21.
Seage, GR, Landers S, Barry A, Groopman J, Lamp GA,
Epstein AM. Medicare care costs of AIDS in
Massachusetts. JAMA. 1986;256:3107-3109.
22. Carter GM, Melnick GA. How Services and Costs Vary by Day of Stay for Medicare Hospital Stays. Santa Monica, Calif: RAND Corporation; 1990. RAND Publication Series R-3870-ProPAC.
23. Lipscomp J, Mark DB, Cowper PA. Comparison of hospital costs derived from cost-to-charge ratios and from a detailed cost accounting system for patients undergoing cardiac procedures. Presented at AHSR and FHSR annual meeting, 1994.
24. Kaplan EL, Meier P. Nonparametric estimation from incomplete observations. J Am Stat Assoc. 1958;53:457-481.
25. Cox DR. Regression models and life-tables. J R Stat Soc. 1972;series B34:187-202.
26. Weintraub WS, Craver JM, Cohen CL, Jones EL, Guyton RA. Influence of age on results of coronary artery surgery. Circulation. 1991;84(suppl III):III-226-III-235.
27. Acinapura AJ, Rose DM, Cunningham JN, Jacobowitz IJ, Kramer MD, Zisbrod Z. Coronary artery bypass in septuagenarians: analysis of mortality and morbidity. Circulation. 1988;78(suppl I):I-179-I-184.
28. Gersh BJ, Kronmal RA, Schaff HV, Frye RL, Ryan TJ, Myers WO, Athearn MW, et al. Longer-term (5 years) results of coronary bypass surgery in patients 65 years old or older: a report from the Coronary Artery Surgery Study. Circulation. 1983;(suppl II):II-190-II-199.
29. Cosgrove DM, Loop FD, Lytle BW, Baillot R, Gill CC, Golding LAR, Taylor PC, Goormastic M. Primary myocardial revascularization: trends in surgical mortality. J Thorac Cardiovasc Surg. 1984;88:673-684. [Abstract]
30.
Gold S, Wong WF, Schatz IJ, Blanchette PL.
Invasive treatment for coronary artery disease in the
elderly. Arch Int Med. 1991;151:1085-1088.
31.
Peterson ED, Jollis JG, Bebchuk JD, DeLong ER,
Muhlbaier LH, Mark DB, Pryor DB. Changes in mortality after
myocardial revascularization in the elderly: the
national Medicare experience. Ann Intern Med. 1994;121:919-927.
32.
Jollis JG, Anckiewicz M, DeLong ER, Pryor DB, Muhlbaier
LH, Mark DB. Discordance of databases designed for claims
payment versus clinical information systems: implications for outcomes
research. Ann Intern Med. 1993;119:844-850.
33.
Iezzoni LI, Foley SM, Daley J, Hughes J, Fisher ES,
Heeren T. Comorbidities, complications and coding bias: does the
number of diagnosis codes matter in predicting in-hospital
mortality? JAMA. 1992;267:2197-2203.
34. Jencks SF, Williams DK, Kay TL. Assessing hospital-associated death from discharge data: the role of length of stay and comorbidity. JAMA. 1988;267:2197-2203.
35.
CASS Principal Investigators. Coronary
Artery Surgery Study (CASS): a randomized trial of coronary
artery bypass surgery: survival data.
Circulation. 1983;68:939-947.
36. The Veterans Administration Cooperative Study Group. Eleven-year survival in the Veterans Administration randomized trial of coronary bypass surgery for stable angina. N Engl J Med. 1984;311:1333-1339. [Abstract]
37. Varnauskas E. Twelve-year follow-up in the randomized European Coronary Surgery Study. N Engl J Med. 1988;319:332-337. [Abstract]
38. RITA Trial Participants. Coronary angioplasty versus coronary artery bypass surgery: the Randomized Intervention Treatment of Angina trial. Lancet. 1993;341:573-580. [Medline] [Order article via Infotrieve]
39.
Hamm CW, Ischinger T, Reimers J, for the GABI Study
Group. Angioplasty versus bypass-surgery in patients with
multivessel disease: reinterventions and complication during 6 month
follow-up. N Engl J Med. 1994;331:1037-1043.
40.
King SB, Lembo NJ, Hall EC, and the EAST Investigators.
The Emory Angioplasty vs Surgery Trial (EAST): analysis
of baseline patient characteristics N Engl J
Med. 1994;331:1044-1050.
41.
Krumholz HM, Forman DE, Kuntz RE, Baim DS, Wei JY.
Coronary revascularization after
myocardial infarction in the very elderly: outcomes and long-term
follow-up. Ann Intern Med. 1993;119:1084-1090.
42. Ko W, Gold JP, Lazzaro R, Zelano JA, Lang S, Isom OW, Krieger KH. Survival analysis of octogenarian patients with coronary artery disease managed by elective coronary artery bypass surgery versus conventional medical treatment. Circulation. 1992;86(suppl II):II-191-II-197.
43. Jones RH. In search of the optimal surgical mortality. Circulation. 1989;79(suppl 1):I-132-I-136.
44. Vogel RA. HCFA's Cooperative Cardiovascular Project: a nationwide quality assessment of acute myocardial infarction. Clin Cardiol. 1994;17:354-356.[Medline] [Order article via Infotrieve]
This article has been cited by other articles:
 |
|
 |
|
  M. Krane, R. Bauernschmitt, A. Hiebinger, M. Wottke, B. Voss, C. C. Badiu, and R. Lange Cardiac reoperation in patients aged 80 years and older. Ann. Thorac. Surg., May 1, 2009; 87(5): 1379 - 1385. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C.-Y. Ng, M. F. Ramli, and Y. Awang Coronary Bypass Surgery in Patients Aged 70 Years and Over: Mortality, Morbidity, Length of Stay and Hospital Cost Asian Cardiovasc Thorac Ann, September 1, 2004; 12(3): 218 - 223. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. K. Srinivasan, A. Y. Oo, A. D. Grayson, R. Lowe, R. A. Perry, B. M. Fabri, and A. Rashid Mid-term survival after cardiac surgery in elderly patients: analysis of predictors for increased mortality Interactive CardioVascular and Thoracic Surgery, June 1, 2004; 3(2): 289 - 293. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. D. Bacchetta, W. Ko, L. N. Girardi, C. A. Mack, K. H. Krieger, O. W. Isom, and L. Y. Lee Outcomes of cardiac surgery in nonagenarians: a 10-year experience Ann. Thorac. Surg., April 1, 2003; 75(4): 1215 - 1220. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 R M Martin, H Hemingway, D Gunnell, K R Karsch, A Baumbach, and S Frankel Population need for coronary revascularisation: are national targets for England credible? Heart, December 1, 2002; 88(6): 627 - 633. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. M. Collins, B. Brorsson, S. Svenmarker, P. A. Kling, and T. Aberg Medium-term survival and quality of life of Swedish octogenarians after open-heart surgery Eur. J. Cardiothorac. Surg., November 1, 2002; 22(5): 794 - 801. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. A. Williams, J. L. Fleg, P. A. Ades, B. R. Chaitman, N. H. Miller, S. M. Mohiuddin, I. S. Ockene, C. B. Taylor, and N. K. Wenger Secondary Prevention of Coronary Heart Disease in the Elderly (With Emphasis on Patients >=75 Years of Age): An American Heart Association Scientific Statement From the Council on Clinical Cardiology Subcommittee on Exercise, Cardiac Rehabilitation, and Prevention Circulation, April 9, 2002; 105(14): 1735 - 1743. [Full Text] [PDF]
|
|
|
|
|
|
S. C. Stamou and P. J. Corso Coronary revascularization without cardiopulmonary bypass in high-risk patients: a route to the future Ann. Thorac. Surg., March 1, 2001; 71(3): 1056 - 1061. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. J. Avery II, S. J. Ley, J. D. Hill, J. J. Hershon, and S. E. Dick Cardiac surgery in the octogenarian: evaluation of risk, cost, and outcome Ann. Thorac. Surg., February 1, 2001; 71(2): 591 - 596. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Czerny, H. Baumer, J. Kilo, A. Zuckermann, G. Grubhofer, O. Chevtchik, E. Wolner, and M. Grimm Complete revascularization in coronary artery bypass grafting with and without cardiopulmonary bypass Ann. Thorac. Surg., January 1, 2001; 71(1): 165 - 169. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. R. Liddicoat, J. M. Redmond, C. M. Vassileva, W. A. Baumgartner, and D. E. Cameron Hypothermic circulatory arrest in octogenarians: risk of stroke and mortality Ann. Thorac. Surg., April 1, 2000; 69(4): 1048 - 1051. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. C. Stamou, G. Dangas, M. K.C. Dullum, A. J. Pfister, S. W. Boyce, A. S. Bafi, J. M. Garcia, and P. J. Corso Beating heart surgery in octogenarians: perioperative outcome and comparison with younger age groups Ann. Thorac. Surg., April 1, 2000; 69(4): 1140 - 1145. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 K. A. Eagle, R. A. Guyton, R. Davidoff, G. A. Ewy, J. Fonger, T. J. Gardner, J. P. Gott, H. C. Herrmann, R. A. Marlow, W. C. Nugent, et al. ACC/AHA guidelines for coronary artery bypass graft surgery: A report of the American College of Cardiology/ American Heart Association task force on Practice Guidelines (Committee to revise the 1991 Guidelines for Coronary Artery Bypass Graft Surgery) J. Am. Coll. Cardiol., October 1, 1999; 34(4): 1262 - 1347. [Full Text] [PDF]
|
|
|
|
|
|
P. Ghosh, D. Holthouse, I. Carroll, R. Larbalestier, and M. Edwards Cardiac reoperations in octogenerians Eur. J. Cardiothorac. Surg., June 1, 1999; 15(6): 809 - 815. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. Noyez, D. P.B. Janssen, J. A.M. van Druten, S. H. Skotnicki, and L. K. Lacquet Coronary bypass surgery: what is changing?: Analysis of 3834 patients undergoing primary isolated myocardial revascularization Eur. J. Cardiothorac. Surg., April 1, 1999; 13(4): 365 - 369. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. W. Hogue JR, B. Barzilai, and V. G. Davila-Roman Stroke Reduction: Diagnosis and Management of the Atherosclerotic Ascending Aorta During Cardiac Surgery Seminars in Cardiothoracic and Vascular Anesthesia, March 1, 1999; 3(1): 17 - 24. [Abstract] [PDF]
|
|
|
|
|
|
C. Blanche, S. S. Khan, A. Chaux, T. A. Denton, M. Sandhu, T.-P. Tsai, and A. Trento Cardiac reoperations in octogenarians: analysis of outcomes Ann. Thorac. Surg., January 1, 1999; 67(1): 93 - 98. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. S. Maharajh, R. G. Masters, and W. J. Keon Cardiac operations in the elderly: who is at risk? Ann. Thorac. Surg., November 1, 1998; 66(5): 1670 - 1673. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Kirsch, L. Guesnier, P. LeBesnerais, M.-L. Hillion, M. Debauchez, J. Seguin, and D. Y. Loisance Cardiac operations in octogenarians: perioperative risk factors for death and impaired autonomy Ann. Thorac. Surg., July 1, 1998; 66(1): 60 - 67. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. W. Akins, W. M. Daggett, G. J. Vlahakes, A. D. Hilgenberg, D. F. Torchiana, J. C. Madsen, and M. J. Buckley Cardiac Operations in Patients 80 Years Old and Older Ann. Thorac. Surg., September 1, 1997; 64(3): 606 - 614. [Abstract] [Full Text]
|
|
|
|
|
|
C. Blanche, J. M. Matloff, T. A. Denton, S. S. Khan, M. A. DeRobertis, S. Nessim, and A. Chaux Cardiac Operations in Patients 90 Years of Age and Older Ann. Thorac. Surg., June 1, 1997; 63(6): 1685 - 1690. [Abstract] [Full Text]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||