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Critical Analysis of Early and Late Outcomes AfterIsolated Coronary Artery Bypass Surgery in ElderlyPatientsAkshat Saxena, BMedSc, Diem T. Dinh, BS, PhD, Cheng-Hon Yap, MBBS, MS,Christopher M. Reid, MS, PhD, Baki Billah, MS, PhD,Julian A. Smith, MBBS, FRACS, Gilbert C. Shardey, MBBS, FRACS, andAndrew E. Newcomb, MBBS, FRACSDepartment of Cardiothoracic Surgery, St. Vincent’s Hospital, Melbourne, Fitzroy; Department of Epidemiology andPreventative Medicine, Monash University, Prahran; Department of Surgery (MMC), Monash University, Monash Medical

Centre, Clayton; Department of Cardiothoracic Surgery, Monash Medical Centre, Clayton; and Cabrini Medical Centre,Malvern, Victoria, Australia

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Background. The proportion of elderly (>80 years)atients undergoing coronary artery bypass surgery

CABG) is increasing.Methods. A retrospective analysis of data, collected by

he Australasian Society of Cardiac and Thoracic Sur-eons Cardiac Surgery Database Program between June001 and December 2009 was performed. Isolated CABGas performed in 21,534 patients; of these, 1,664 (7.7%)ere at least 80 years old (group 1). Patient characteris-

ics, morbidity, and short-term mortality of these patientsere compared with those aged less than 80 years (group

). The long-term outcome of group 1 patients afterABG surgery was compared with an age and sex-atched Australian population.Results. Patients over 80 years old were more likely to

e female (36.6% vs 17.3%, p < 0.001) and presentedignificantly more often with heart failure, hypertension,

nd triple-vessel disease (all p < 0.05). The 30-day mor-

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Surgery, St Vincent’s Hospital Melbourne, Fitzroy, Victoria, Australia;e-mail: a.saxena@student.unimelb.edu.au.

© 2011 by The Society of Thoracic SurgeonsPublished by Elsevier Inc

ality was higher in group 1 patients (4.2% vs 1.5%, p <.001). Group 1 patients also had an increased risk ofomplications, including prolonged (>24 hours) ventila-ion (14.2% vs 8.2%, p < 0.001), renal failure (7.3% vs.4%, p < 0.001), and mean intensive care unit stay (60.7s 42.5 hours, p < 0.001). The 5-year survival of elderlyatients (73%) was comparable with the age-matchedustralian population. Independent risk factors for 30-ay mortality in group 1 patients included preoperativeenal failure (p � 0.010), congestive heart failure (p �.014), and a nonelective procedure (p � 0.016).

Conclusions. Elderly patients who undergo isolatedABG have significantly lower perioperative risks

han have been previously reported. The long-termurvival of these patients is comparable with an age-djusted population.

(Ann Thorac Surg 2011;92:1703–11)

© 2011 by The Society of Thoracic Surgeons

The populations of developed countries, includingAustralia, are rapidly ageing. In the past two

ecades, the number of Australians over the age of 80as increased by 140%, compared with a total popula-

ion growth of 30% over the same period [1]. This trends set to continue. The Australian Bureau of Statisticsrojects that the proportion of the Australian popula-

ion over the age of 85 will increase from 1.6% in 2007o between 4.9% and 7.3% in 2056 [2]. This demo-raphic shift is even more pronounced in other devel-ped countries such as Germany and Japan. Cardio-ascular diseases are the leading cause of morbiditynd mortality in this population [3]; consequently, areater number of patients over the age of 80 arendergoing coronary artery bypass graft (CABG) sur-ery [4, 5]. Advanced age is associated with decreased

Accepted for publication May 24, 2011.

Address correspondence to Dr Saxena, Department of Cardiothoracic

hysiologic reserve and increased comorbidities, andherefore CABG surgery in these patients has beenraditionally associated with high rates of periopera-ive mortality and morbidity [6 –10].

However, incremental advances in all aspects of care ofhe coronary bypass patient have led to improved outcomesn octogenarian patients undergoing CABG surgery in

ore recent years [4, 11-14]. Nevertheless, ongoing con-erns exist as to whether postoperative survival outcomesfter cardiac surgery in octogenarians are sufficient toustify the risks and costs of this procedure. Several single-enter Australian studies have attempted to examine thismportant clinical issue [11, 15, 16]. However, they haveeen limited by small patient numbers and limited follow-p. The primary aim of the current study is to criticallyssess the early and long-term outcomes in a large numberf elderly Australian patients who have undergone CABGy analyzing prospectively collected data from the Austral-sian Society of Cardiac and Thoracic Surgeons (ASCTS)

ardiac Surgery Database. The secondary aim is to identify

0003-4975/$36.00doi:10.1016/j.athoracsur.2011.05.086

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factors associated with early and late mortality in octoge-narian patients in order to optimize selection criteria.

Patients and Methods

The inclusion criterion for the study was all patients under-going isolated CABG between June 1, 2001 and December31, 2009 at hospitals in Australia participating in the ASCTSCardiac Surgery Database. Patients having concomitantvalve surgery or other concurrent cardiac surgical proce-dures were excluded from this study. All 6 Victorian publichospitals that perform adult cardiac surgery, The RoyalMelbourne Hospital, The Alfred Hospital, Monash MedicalCentre, The Geelong Hospital, Austin Hospital, and StVincent’s Hospital Melbourne, were involved in the pro-spective data collection during the entire period. Addition-ally, 14 cardiac surgical units from South Australia, NewSouth Wales, and Queensland entered the database projectin the last 30 months of the study period and contributed32% of the total patient numbers.

The ASCTS database contains detailed information onpatient demographics, preoperative risk factors, operativedetails, postoperative hospital course, and morbidity andmortality outcomes. These data were collected prospec-tively using a standardized dataset and definitions. Datacollection and audit methods have been previously de-scribed [5]. In the state of Victoria, the collection andeporting of cardiac surgery data is compulsory and man-ated by the state government; hence, it is all-inclusive.ata validation has been a major focus since the establish-ent of the ASCTS database. The data are subjected to

oth local validation and an external data quality auditrogram, which is performed on site to evaluate the com-leteness (defined as � 1% missing data for any variable)nd accuracy (97.4%) of the data held in the combinedatabase. Audit outcomes are used to assist in furtherevelopment of appropriate standards. The Ethics Commit-

ee of each participating hospital had previously approvedhe use of de-identified patient data contained within the

Table 1. Intraoperative Characteristics, Stratified by Age

Outcome Age �80 Year

Permanent stroke (%) 147 (0.73)Transient stroke (%) 72 (0.36)Postoperative myocardial infarction (%) 145 (0.73)New renal failure (%) 667 (3.36)Deep sternal wound infection (%) 144 (0.72)Septicemia (%) 184 (0.93)Multisystem failure (%) 138 (0.69)Gastrointestinal complications (%) 200 (1.0)Prolonged ventilation (%) 2637 (13.27)Return to theatre (%) 949 (4.78)

Return to theatre for bleeding (%) 458 (2.30)

database for research and waived the need for individualpatient consent.

For the purpose of this study, patients were divided intotwo groups: those undergoing isolated CABG who were 80years of age or greater (group 1) and those undergoingisolated CABG who were less than 80 years of age (group 2).Preoperative characteristics, early outcomes, and long-termsurvival were compared between the two groups.

Twelve early postoperative outcomes were analyzed.These were the following: (1) 30-day mortality, defined asdeath within 30 days of operation; (2) permanent stroke,defined as a new central neurologic deficit persisting forgreater than 72 hours; (3) transient stroke, defined as a newtransient neurologic deficit that resolves completely within72 hours (transient ischemic attack or reversible ischemicneurologic deficit); (4) postoperative acute myocardial in-farction, defined as at least two of the following: enzymelevel elevation, new cardiac wall motion abnormalities, ornew Q waves on serial electrocardiograms; (5) new renalfailure, defined as at least two of the following: serumcreatinine increased to more than 200 �mol/L, doubling orgreater increase in creatinine versus preoperative value, ornew requirement for dialysis or hemofiltration; (6) prolongedventilation (�24 hours); (7) multisystem failure, defined asconcurrent failure of two or more of the cardiac, respiratory, orrenal systems for at least 48 hours; (8) gastrointestinal compli-cations, defined as postoperative occurrence of any gastroin-testinal complication; (9) deep sternal infection involving mus-cle and bone, as demonstrated by surgical exploration and oneof the following: positive cultures or treatment with antibiotics;(10) return to the operating theatre for any cause; and (11)return to the operating theatre for bleeding.

To assess the role of octogenarian status as a predictorfor each early outcome, logistic regression analysis wasused to adjust for 19 preoperative patient variables, withthe outcome as the dependent variable (variables inTable 1). Logistic regression analysis techniques werealso applied to identify preoperative variables associatedwith early mortality in octogenarian patients.

Age �80 Years p Value

Age �80Years

AdjustedOdds Ratio

(95% CI)

22 (1.32) 0.517 1.19 (0.70–2.01)15 (0.90) �0.001 2.96 (1.63–5.39)13 (0.78) 0.721 0.89 (0.47–1.68)

122 (7.34) �0.001 2.34 (1.88–2.93)14 (0.84) 0.376 1.32 (0.72–2.43)29 (1.74) 0.002 1.94 (1.27–2.98)33 (1.99) �0.001 2.46 (1.59–3.81)42 (2.53) �0.001 2.32 (1.60–3.37)

234 (14.10) �0.001 1.75 (1.48–2.07)120 (7.22) 0.001 1.46 (1.18–1.81)

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51 (3.07) 0.083 1.32 (0.96–1.81)

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Thirty-day mortality was determined by checking the hos-pital administration system for evidence of 30-day mortalityafter surgery. All patients or next of kin must be followed up(or attempted to be followed up) at 30-days postprocedure.Alternatively, if the required information is able to be verifiedby a reliable source (ie, general practitioner or medical recordreview of postcardiac surgery procedure clinic visit), then thiscan be used. All mortalities were also verified using theNational Death Index (NDI) linkage.

Long-term survival status was obtained from the NDI. Only3% of the patients’ 30-day mortality data within our databasecould not be matched with NDI data. Their death data werestill included in the current analysis. All the remaining pa-tients were able to be linked with the NDI registry. The closingdate was March 18, 2010. A Kaplan-Meier estimate of survivalwas obtained. Survival was compared with age-matched andsex-matched population life estimates from the AustralianBureau of Statistics [17]. Differences in long-term survival wereassessed by the log-rank test. The role of octogenarian statusin long-term survival was assessed by constructing a Coxproportional hazards model using octogenarian status andother preoperative patient characteristics as variables. A Coxproportional hazards model was also applied to identify pre-operative variables associated with long-term survival in oc-togenarian patients. Continuous variables are presented asmean � one standard deviation. The Mann-Whitney U test

as used to compare two groups of continuous variables. The2 test was used to compare groups of categoric variables. All

calculated values of p were two-sided, and a p value less than.05 was considered significant. Statistical analysis was per-ormed using SPSS for Windows version 17.0 (SPSS, Munich,ermany). Although the ASCTS has developed a 30-dayortality risk-adjustment model as part of the routine data-

ase service provided to all participants, this was not used inhe current study because elderly status (�80 years) was notpecifically addressed.

Results

Patient Demographics and Preoperative VariablesOverall, of 21,534 patients who met the study inclusion criteria,1,662 (7.7%) were aged 80 years and over while 19,872 (92.3%)were aged less than 80 years. Preoperative and demographiccharacteristics of these two groups are provided in Table 2.

he mean age in group 1 was 82.39 � 2.24 years comparedith 59.01 � 7.77 in group 2. Group 1 patients were more likely

o be female (36.6% vs 21.0%, p � 0.001).Patients in group 1 were less likely to have diabetes

25.5% vs 33.3%, p � 0.001), hypercholesterolemia (73.2%s 81.0%, p � 0.001) or obesity (16.9% vs 33.8%, p � 0.001).hey were also more likely to have hypertension (83.5% vs6.4%, p � 0.001), chronic obstructive pulmonary disease14.1% vs 11.9%, p � 0.008), cerebrovascular disease (19.0%s 10.4%, p � 0.001), peripheral vascular disease (23.8% vs1.9%, p � 0.001), recent (�21 days) myocardial infarction

(29.5% vs 25.1%, p � 0.001), congestive heart failure(21.5% vs 15.3%, p � 0.001), and unstable angina (10.0% vs.3%, p � 0.001). They were also more likely to have an

impaired left ventricular ejection fraction (58.7% vs 52%, t

p � 0.001) and have marked or severe symptoms fromtheir heart disease (New York Heart Association class IIIor IV) (30.0% vs 25.8%, p � 0.001). Group 1 patients had ahigher incidence on triple-vessel disease (79.1% vs 72.0%p � 0.001) and left main coronary artery lesions (34.4% vs4.9%, p � 0.001). They were more likely than group 2atients to have undergone a nonelective procedure

46.3% vs 42.2%, p � 0.001).

Intraoperative DataThere were some differences in intraoperative variablesbetween the two groups. The use of off-pump techniqueswas lower in the group 1 patients (5.7% vs 8.4%, p � 0.001).

here was a nonsignificant trend toward an increased meanumber of distal anastomoses in the elderly group (3.20 �.08 vs 3.15 � 1.15, p � 0.057). The duration of cardiopul-onary bypass support at 89.74 � 37.84 vs. 89.99 � 42.35inutes (p � 0.819) and aortic cross-clamping at 63.66 �

6.40 and 65.13 � 34.15 (p � 0.095) was not significantlyifferent in the two groups. Internal mammary artery graftse was significantly lower in group 1 patients (91.0% vs4.6%, p � 0.001). Cardioplegia was used less commonly inlderly patients (95.0% vs 96.2%, p � 0.013). There was noifference in the use of inotropes on the day of surgeryetween groups 1 and 2 (1.3% vs 1.3%, p � 0.801). There waso difference in the use of aspirin within 7 days of surgeryetween the two groups (60.7% vs 62.6%, p � 0.184).

Early OutcomesSignificant differences between the groups were docu-mented in the early postoperative outcome (Table 1). Over-all 30-day mortality was 1.6%. The 30-day mortality was4.2% in the elderly group and 1.4% in the non-elderly group(p � 0.001). After adjustment for differences in patient

ariables, elderly status remained a predictor for 30-dayortality (odds ratio [OR], 2.16; 95% confidence interval

CI] 1.58 to 2.97), transient stroke (OR, 2.96; 95% CI 1.63 to.39), new renal failure (OR, 2.34; 95% CI 1.88 to 2.93),epticemia (OR, 1.94; 95% CI 1.27 to 2.98), multisystemailure (OR, 2.46; 95% CI 1.59 to 3.81), prolonged ventilationOR, 1.75; 95% CI 1.48 to 2.07), and return to theatre (OR,.46; 95% CI, 1.18 to 1.81). The logistic regression modelredicting 30-day mortality is shown in Table 3. The modelas a Hosmer-Lemeshow �2 statistic of 4.20 (p � 0.84).roup 1 patients had a higher mean postoperative length of

tay (11.3 � 9.6 vs 8.4 � 9.1 days, p � 0.001) and intensive carenit stay (60.7 � 98.5 vs 42.5 � 96.5 hours, p � 0.001)ompared with non-octogenarian patients.

Late OutcomesLong-term survival at 1, 3, 5, and 7 years postoperativelywas lower in group 1 compared with group 2 (92.2% vs97.1%, 86.0% vs 94.5%, 73.2% vs 90.2%, and 61.3% vs 85.4%,respectively) (Fig 1). This difference persisted after adjust-ing for difference in patient variables (OR, 2.25; 95% CI 1.97to 2.57; p � 0.001). Similarly, long-term survival at 1, 3, 5, and

years was lower in group 1 patients compared witheptuagenarian patients (70 � age � 80) (92.2% vs 95.2%,6.0% vs 90.9%, 73.2% vs 84.0% and 61.3% vs 76.9%, respec-

ively) (Fig 2). This difference also persisted after adjusting

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for differences in patient variables (OR, 1.61; 95% CI 1.40 to1.85; p � 0.001). However, the survival of group 1 patients’

ost-CABG is comparable with the survival of an age-djusted and sex-adjusted Australian population data. The-year survival of male group 1 patients (mean age, 82.5) at9% is comparable with the age-matched (mean age, 82)xpected survival of 62.5% (Fig 3). Similarly, the 5-yearurvival of female group 1 patients (mean age, 82.5) at 79.8%s comparable to the age-adjusted (mean age, 82) survival of2.3% (Fig 4). A Cox regression model predicting lateortality is summarized in Table 3. Apart from age, other

factors associated with survival included chronic obstruc-tive pulmonary disease (OR, 1.47; 95% CI 1.31 to 1.65),diabetes mellitus (OR, 1.20; 95% CI 1.09 to 1.33), hypercho-lesterolemia (OR, 0.70; 95% CI 0.63 to 0.79), hypertension(OR, 1.37; 95% CI 1.20 to 1.55), cerebrovascular disease (OR,

Table 2. Preoperative Characteristics and Patient Demograph

Preoperative Variables A

Total number of patients (%)Age (mean � SD)Female (%)Chronic obstructive pulmonary disease (%)

iabetes mellitus (%)ypercholesterolemia (%)ypertension (%)erebrovascular disease (%)eripheral vascular disease (%)enal failure (%)revious cardiothoracic intervention (%)ecent myocardial infarction (�21 days) (%)istory of congestive heart failure (%)nstable angina (%)eft main stenosis �50% (%)eft ventricular ejection fractionNormal (EF �0.60) (%)Mild (EF �0.45) (%)Moderate (EF 0.30–0.45) (%)Severe (EF �0.30) (%)besity (%)ew York Heart Association classificationClass I (%)Class II (%)Class III (%)Class IV (%)umber of diseased vessels1 (%)2 (%)3 (%)

ritical preoperative state (%)tatusElective (%)Emergency/salvage (%)Urgent (%)

EF � ejection fraction.

1.41; 95% CI 1.25 to 1.59), peripheral vascular disease (OR,

1.72; 95% CI 1.53 to 1.92), renal failure (OR, 2.25; 95% CI 1.89to 2.69), obesity (OR, 0.90; 95% CI 0.81 to 0.99), congestiveheart failure (OR, 1.61; 95% CI 1.45 to 1.80), left main stemstenosis (OR, 1.16; 95% CI 1.05 to 1.29), left ventricularejection fraction less than 0.45 (OR, 1.61; 95% CI 1.45 to 1.80),New York Heart Association class III or IV (OR, 1.23;95% CI 1.10 to 1.36), triple-vessel disease (OR, 1.26; 95%CI 1.11 to 1.42), nonelective procedure (OR, 1.13; 95%CI 1.00 to 1.26), and critical preoperative state (OR,1.43; 95% CI 1.24 to 1.66).

Factors Predictive of Mortality in OctogenarianPatientsTable 4 demonstrates the model predicting 30-day andlong-term mortality in group 1 patients. The predictorsfor 30-day mortality were renal failure (OR, 3.24; 95% CI

tratified by Age

80 Years Age �80 Years p Value

2 (92.3) 1662 (7.7) –1 (7.77) 82.39 (2.24) �0.0012 (21.0) 608 (36.6) �0.0016 (11.9) 234 (14.1) 0.0082 (33.3) 423 (25.5) �0.0013 (81.0) 1216 (73.2) �0.0012 (76.4) 1387 (83.5) �0.0012 (10.4) 316 (19.0) �0.0012 (11.9) 395 (23.8) �0.0019 (3.3) 57 (3.4) 0.6203 (3.6) 61 (3.7) 0.9538 (25.1) 491 (29.5) �0.0018 (15.3) 358 (21.5) �0.0015 (8.3) 167 (10.0) 0.0146 (24.9) 572 (34.4) �0.001– – �0.0019 (48.0) 657 (41.3) –1 (31.6) 549 (34.5) –7 (15.8) 319 (20.0) –1 (4.6) 67 (4.2) –8 (33.8) 281 (16.9) �0.001– – �0.0019 (39.5) 513 (32.8) –3 (34.7) 582 (37.2) –0 (16.9) 347 (22.2) –9 (8.9) 122 (7.8) –– – �0.0010 (5.1) 47 (2.9) –7 (22.9) 298 (18.1) –2 (72.0) 1304 (79.1) –2 (7.3) 121 (7.3) 0.965– – 0.0024 (57.8) 892 (53.7) –1 (4.3) 87 (5.2) –5 (37.9) 683 (41.0) –

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1.16 to 4.30), and critical preoperative state (OR, 2.47; 95%CI 1.18 to 5.15), while hypercholesterolemia appears to beprotective (OR, 0.48; 95% CI 0.26 to 0.87). The predictorsfor late mortality were peripheral vascular disease (OR,1.52; 95% CI 1.15 to 2.00), congestive heart failure (OR,1.42; 95% CI 1.08 to 1.85), and left ventricular ejectionfraction less than 0.45 (OR, 1.59; 95% CI 1.22 to 2.08),

Table 3. Predictors for 30-Day and Late Mortality in Entire C

Preoperative VariablesO

(

Age �80 years 2.16Female 1.32Chronic obstructive pulmonary disease 1.12Diabetes mellitus 0.99Hypercholesterolemia 0.78Hypertension 1.40Cerebrovascular disease 0.90Peripheral vascular disease 1.46Renal failure 1.82Obesity 0.93Recent myocardial infarction 1.52History of congestive heart failure (%) 2.03

nstable angina (%) 1.52eft main stenosis �50% 1.32eft ventricular ejection fraction �0.45 1.97ew York Heart Association classification III or IV 1.49riple-vessel disease 1.19onelective procedure 1.66ritical preoperative state 2.35

CI � confidence interval.

Fig 1. Overall survival of patients after coronary artery bypass graft

(CABG) surgery, stratified by age.

while female gender (OR, 0.68; 95% CI 0.52 to 0.88)appears to be protective.

Comment

The rapidly ageing populations of developed countrieshave significantly altered the demographic profile of

t (n � 21,534)

Early Mortality Late Mortality

atioCI) p Value

Odds Ratio(95% CI) p Value

–2.97) �0.001 2.25 (1.97–2.57) �0.001–1.72) 0.035 1.01 (0.91–1.13) 0.810–1.54) 0.470 1.47 (1.31–1.65) �0.001–1.28) 0.961 1.20 (1.09–1.33) �0.001–1.03) 0.076 0.70 (0.63–0.79) �0.001–1.93) 0.039 1.37 (1.20–1.55) �0.001–1.27) 0.557 1.41 (1.25–1.59) �0.001–1.96) 0.012 1.72 (1.53–1.92) �0.001–2.74) 0.004 2.25 (1.89–2.69) �0.001–1.21) 0.567 0.90 (0.81–0.99) 0.046–1.99) 0.003 1.04 (0.92–1.17) 0.535–2.67) �0.001 1.61 (1.45–1.80) �0.001–2.06) 0.006 0.96 (0.82–1.12) 0.576–1.69) 0.027 1.16 (1.05–1.29) 0.005–2.56) �0.001 1.61 (1.45–1.80) �0.001–1.94) 0.003 1.23 (1.10–1.36) �0.001–1.62) 0.268 1.26 (1.11–1.42) �0.001–2.24) 0.001 1.13 (1.00–1.26) 0.037–3.17) �0.001 1.43 (1.24–1.66) �0.001

Fig 2. Comparison of overall survival after coronary artery bypass

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(1.58(1.02(0.82(0.77(0.59(1.02(0.64(1.09(1.21(0.71(1.15(1.54(1.13(1.03(1.51(1.14(0.88(1.23(1.74

graft (CABG) surgery in septuagenarian and octogenarian patients.

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patients undergoing CABG surgery. An increasing pro-portion of patients undergoing CABG surgery are 80years or older and this trend is expected to continue [4, 5].Early single-center studies demonstrated that cardiacsurgery in these patients was associated with in-hospitalmortality rates of more than 10% [7, 8, 10], with one studyreporting early mortality as high as 24% [6]. However,continuous refinements in surgical technique and peri-operative management have more recently resulted insignificantly improved outcomes. A recent analysis ofThe Society of Thoracic Surgeons’ database showed anoperative mortality of 7.1% in octogenarians who under-went isolated CABG surgery between 1997 and 2000 [14].Many other contemporary series have also reportedimprovements in mortality for this group, suggesting thatperforming cardiac surgery in elderly patients is justified[4, 12–14].

The 30-day and in-hospital mortality rates of 4.2% and4.5%, respectively, in the present study, are among thelowest reported in a large number of patients in thispatient age group to date. The low early mortality wasattained even though a high proportion of patients pre-sented with significant comorbidities including diabetes,severely depressed ejection fraction, cerebrovascular dis-ease, renal impairment, and chronic obstructive lungdisease. Therefore, the lower early mortality rates werenot solely achieved through patient selection. They morelikely reflect the significant improvements in surgical andperioperative management that have taken place, espe-cially given that all patients in this study underwentsurgery relatively recently. Moreover, the fact that thisstudy represents the collaborative efforts of 18 institu-tions reduces inter-institutional bias and suggests thatrelatively good outcomes can be attained in octogenarianpatients in the contemporary era provided they aresupported by a network of well-resourced, multidisci-

Fig 3. Overall survival of male elderly patients after coronary arterybypass grafting (CABG) compared with expected survival for theage-matched Australian male population.

plinary care facilities.

Compared with younger patients, elderly patientswere independently at a higher risk of 30-day mortalityand other early complications, including renal failure,gastrointestinal complications, multisystem failure, pro-longed (�24-hour) ventilation, and return to theatre. Themajority [4, 8, 13, 18], but not all [12], of the studies havealso shown that octogenarian status is independentlyassociated with worse early outcomes. This disparityreflects the fact that elderly patients have less physiologicreserve and greater comorbidities than younger patients.Interestingly, in our population there was no differencein the rate of bleeding or permanent stroke, two compli-cations which have previously been shown to be moreprevalent in the elderly [4, 19]. The overall stroke rate of2.3% in octogenarians in the present study is significantlylower than that reported by most other contemporarystudies [7, 20, 21]. Although this study did not specificallyexamine the contribution of specific aspects of perioper-ative management, it is likely that adjuncts such asroutine intraoperative epiaortic scanning, use of axillarycannulation in reoperations, and improved cardiopulmo-nary bypass strategies favoring high perfusion pressuresin elderly patients may have helped to attain the lowrates of postoperative stroke [12]. The mean length ofintensive care unit stay and postoperative length ofhospital stay were higher in elderly patients. This wouldbe expected to correlate with increased resource utiliza-tion and cost of CABG surgery in the elderly. Australianstudies assessing cost of CABG in the elderly are lacking.However, studies from North America have shown thatthe cost of CABG in the elderly is higher than youngerpatients [9, 22] but is nevertheless highly cost effective22]. Overall, the unfavorable comparison with a youngerohort should not be viewed in isolation. It must be notedhat continuous improvements in cardiac surgery have

ade it safer for all patients, and that compared with

Fig 4. Overall survival of female elderly patients after coronary ar-tery bypass grafting (CABG) compared with expected survival for

the age-matched Australian female population.

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historical controls an absolute improvement in the earlyoutcomes of octogenarian patients has taken place.

Identification of high-risk patients within the octoge-narian population has been attempted by several studies[12]. This may facilitate better patient selection andthereby improve outcomes. Unfortunately, many previ-ous studies have been restricted by a small sample size.Consistent with several previous reports we showed thatcomorbid factors such as renal failure, impaired ejectionfraction, and a critical preoperative state were associatedwith early mortality [10-12]. Contrary to other reports

ypercholesterolemia was shown to have a protectiveffect, which may reflect the positive effect of statin drugsn early outcomes [11]. Importantly, there was no differ-nce in 30-day mortality rates between elderly men andomen. In Australia, adoption of off-pump techniquesas been somewhat slower than in many centers in Northmerica and Europe. Interestingly, in the current study

he use of off-pump techniques was significantly lower inlderly patients. This is despite the fact that elderlyatients presented more often with comorbidities. Sev-ral investigators have argued that off-pump CABG isore suitable than on-pump CABG in patients with

ignificant comorbidities [23, 24]. Our study, therefore,ighlights the need to investigate further.Expectedly, long-term survival was worse in group 1

ompared with group 2 patients. The octogenarian groupad an average that was 23 years older than the youngerroup. Nevertheless, we have shown that the 5-yearurvival of group 1 patients undergoing CABG is compa-

Table 4. Predictors for 30-Day and Late Mortality in Octogen

Preoperative VariablesO

(

ge, years (mean � SD) 1.02emale 0.83hronic obstructive pulmonary disease 1.46iabetes mellitus 0.64ypercholesterolemia 0.48ypertension 1.05erebrovascular disease 0.62eripheral vascular disease 0.91enal failure 3.24besity 1.11ecent myocardial infarction 1.63istory of congestive heart failure (%) 2.23nstable angina (%) 1.16eft main stenosis �50% 1.15

Left ventricular ejection fraction �0.45 1.42New York Heart Association classification III or IV 1.43Triple-vessel disease 1.98Nonelective procedure 1.95Critical preoperative state 2.47

CI � confidence interval.

able with, if not better than, the age-matched and

sex-matched Australian population. This is an excellentfinding and is consistent with the fact that ischemic heartdisease is the leading cause of death in both Australianmen and women. The 5-year survival of 73.2% in a groupof patients with a mean age of 82.5 is quite remarkablegiven the lack of consensus regarding the value of CABGin the elderly even today. Our data, therefore, demon-strate that isolated CABG surgery is an efficacious pro-cedure which produces excellent results, even in a high-risk patient cohort. The previous perception that CABGsurgery in elderly patients is associated with high peri-operative mortality and limited long-term survival mustbe reevaluated in light of our excellent results. Similarfindings have also been reported elsewhere. Filsoufi andcolleagues [12] reported a 5-year survival of 66.3% in aseries of 282 octogenarian patients who underwent iso-lated CABG in a single institution. Other contemporaryseries have shown 5-year survival of between 56% and70% [11, 20, 25, 26]. Therefore, our long-term resultscompare favorably with the published literature. Ananalysis of the factors associated with long-term survivalidentified female gender as a positive prognostic factor.This observation can be explained by the fact thatfemales have a longer life expectancy than males. It is,however, an important finding, given that many clini-cians still adopt a more cautious approach to CABGsurgery in females given the previous associations witha poorer perioperative outcome. The absence of pe-ripheral vascular disease or severely impaired ventric-ular function was also associated with greater long-

Cohort (n � 1,662)

arly Mortality Late Mortality

atioCI) p Value

Odds Ratio(95% CI) p Value

–1.16) 0.804 1.05 (1.00–1.11) 0.051–1.51) 0.533 0.68 (0.52–0.88) 0.003–2.99) 0.298 1.08 (0.80–1.46) 0.620–1.31) 0.220 1.04 (0.79–1.37) 0.767–0.87) 0.016 0.77 (0.59–1.00) 0.054–2.23) 0.907 0.91 (0.66–1.25) 0.563–1.39) 0.245 1.03 (0.77–1.38) 0.860–1.90) 0.805 1.52 (1.15–2.00) 0.003–9.25) 0.028 1.65 (1.00–2.75) 0.052–2.41) 0.789 1.11 (0.80–1.54) 0.518–3.09) 0.137 1.09 (0.81–1.46) 0.590–4.30) 0.016 1.42 (1.08–1.85) 0.011–2.48) 0.705 1.33 (0.93–1.91) 0.119–2.06) 0.629 1.19 (0.93–1.53) 0.174–2.63) 0.272 1.59 (1.22–2.08) 0.001–2.69) 0.270 1.15 (0.88–1.49) 0.305–5.17) 0.162 1.15 (0.83–1.62) 0.403–3.99) 0.067 0.94 (0.71–1.25) 0.689–5.15) 0.016 1.14 (0.76–1.70) 0.536

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Whether the long-term survival of very elderly patientsafter CABG surgery is accompanied by a good quality-of-life is an important consideration when deciding toperform CABG in the very elderly. This feature was notexamined in the present study but there is evidence thatcardiac surgery in octogenarians is associated withmeaningful and sustained improvements in the qualityof life. Fruitman and colleagues [27] showed that at amean of 16 months postoperatively the New York HeartAssociation functional class was I and II in 77% and 18%of octogenarians, respectively. Moreover, 84% were stillliving at home. Similarly, Kumar and colleagues [28], intheir review of 68 octogenarians undergoing CABG orvalve surgery, found that 85% of patients reported that inretrospect they would definitively have made the deci-sion to undergo open heart surgery. Further investigationis clearly required but these data suggest CABG surgeryis associated with an improved quality of life in elderlypatients.

The current study has several strengths and weak-nesses. This large, contemporary study from a robustlyvalidated multiinstitutional database is likely to accu-rately reflect real world practice. The main limitation isthat it is a retrospective review and although capturingall surgical patients there is likely to be selection biaspresent. Our dataset also does not currently collect dataon details on surgical technique including hypothermiaand myocardial protection. Moreover, due to the retro-spective nature of the dataset, it is not possible to addresstopics which may be of clinical relevance. For example, itis not possible to determine the reasons why off-pumpprocedures were performed in some elderly patients butnot others. A prospective clinical trial, rather than aretrospective analysis, would therefore be ideal to furtherinvestigate some of the trends that were observed in thisstudy.

Despite its limitations, our study provides valuabledata and insight. First, given its contemporary nature, ourstudy demonstrates that isolated CABG surgery can besafely performed in elderly patients in the modern era. Itshows that the continuous improvements in cardiac sur-gery that have taken place in the last two decades havesignificantly improved outcomes. Second, we have re-ported a 30-day mortality that is among the lowestreported in a large group of patients to date. As such,even in a high-risk elderly cohort, CABG surgery isrelatively safe. This is particularly important, given thatthe proportion of elderly patients undergoing cardiacsurgery will increase both because of the ageing popula-tion of developed countries and the increased utilizationof percutaneous coronary interventions. Third, our studydemonstrates that long-term survival in elderly patientsis significantly better than the age-adjusted Australianpopulation. This excellent result provides strong evi-dence that CABG surgery in elderly patients is extremelyefficacious. Once again, our long-term survival rates arecomparable with the best reported data to date. Hence,our study used contemporary data to demonstrate thatoutcomes of CABG in elderly patients are significantly

better than otherwise thought.

In conclusion, this multicenter Australian study hasshown that patients over 80 years of age can undergoCABG in the contemporary era with acceptable mortalityand morbidity and good long-term survival. Althoughearly and late outcomes were worse than younger pa-tients, they are comparable with the best published datafor a similar age group from elsewhere. Moreover, long-term survival was similar to, if not better than, theage-adjusted Australian population. These data are par-ticularly encouraging given that the proportion of pa-tients undergoing CABG surgery who are octogenariansis steadily increasing. Nevertheless, an individualizedassessment of the risks and benefits of cardiac surgery inelderly patients guided by established prognostic factorsis necessary to optimize outcomes and justify the in-creased risks and costs of this procedure.

The Australasian Society of Cardiac and Thoracic Surgeons(ASCTS) Cardiac Surgery Database Program is funded by theDepartment of Human Services, Victoria, and the Health Ad-ministration Corporation (GMCT) and the Clinical ExcellenceCommission (CEC), NSW.

The following investigators, data managers, and institutionsparticipated in the ASCTS Database: Alfred Hospital: Pick A,Duncan J; Austin Hospital: Seevanayagam S, Shaw M; CabriniHealth: Shardey G; Geelong Hospital: Morteza M, Bright C;Flinders Medical Centre: Knight J, Baker R, Helm J; JessieMcPherson Private Hospital: Smith J, Baxter H; Hospital: JohnHunter Hospital: James A, Scaybrook S; Lake Macquarie Hos-pital: Dennett B, Jacobi M; Liverpool Hospital: French B, HewittN; Mater Health Service Hospital: Diqer AM, Archer J; MonashMedical Centre: Smith J, Baxter H; Prince of Wales Hospital:Wolfenden H, Weerasinge D; Royal Melbourne Hospital: Skill-ington P, Law S; Royal Prince Alfred Hospital: Wilson M, TurnerL; St George Hospital: Fermanis G, Redmond C; St Vincent’sHospital, VIC: Yii M, Newcomb A, Mack J, Duve K; St Vincent’sHospital, NSW: Spratt P, Hunter T; The Canberra Hospital:Bissaker P, Butler K; Townsville Hospital: Tam R, Farley A; andWestmead Hospital: Costa R, Halaka M.

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