Recovery of Self-Reported Functional
Capacity After Coronary Artery Bypass
Surgery*
Lee M. Pierson, MS; H. James Norton, PhD; William G. Herbert, PhD;
Mary E. Pierson, MSN; Warren K. Ramp, PhD; Gary M. Kiebzak, PhD;
John M. Fedor, MD; and Joseph W. Cook, MD
Study objectives: This study was conducted to determine the effects of age, gender, comorbid
conditions, and exercise on the recovery of self-reported functional capacity after coronary artery
surgery, and to identify predictors of 1-year functional capacity.
Patients: One hundred ninety-eight patients undergoing coronary artery bypass graft surgery.
Measurements and results: Self-reported functional capacity was evaluated before surgery, and
3 months and 1 year postoperatively using the Veterans Specific Activity Questionnaire (VSAQ).
Patients were classified into groups based on age, gender, comorbid conditions, and postoperative
exercise. Repeated-measures analysis of variance was used to determine if groups differed with respect
to functional capacity recovery and multiple linear regression was used to identify predictors of 1-year
VSAQ score. A significant time by age interaction was found (p ⴝ 0.0001), with a more protracted
recovery for older patients. There were significant group effects for gender (p ⴝ 0.0001), and presence
of comorbid conditions (p ⴝ 0.0009); however, there were no time/group interactions for these
variables. A significant group effect was found for postoperative exercise (p ⴝ 0.0001), with a trend
toward group/time interaction (p ⴝ 0.096). Predictors of 1-year functional capacity were VSAQ score
in the year prior to surgery and performance of regular aerobic exercise in the postoperative period.
Conclusions: This study suggests that older patients attain good self-reported functional outcomes after
surgery; however, the time course for recovery is more protracted than for younger patients.
Functional capacity in the year prior to surgery and postoperative exercise are key predictors of 1-year
functional capacity.
(CHEST 2003; 123:1367–1374)
Key words: coronary artery bypass surgery; elderly; functional capacity
Abbreviations: ANOVA ⫽ analysis of variance; CABG ⫽ coronary artery bypass graft; CAD ⫽ coronary artery disease;
MET ⫽ metabolic equivalent; NYHA ⫽ New York Heart Association; V̇o2 ⫽ oxygen consumption; V̇o2pk ⫽ peak
oxygen consumption during maximal exercise treadmill test; VSAQ ⫽ Veterans Specific Activity Questionnaire;
VSAQ-Y ⫽ Veterans Specific Activity Questionnaire recall score regarding the year before CABG surgery
number of coronary artery bypass graft
T he(CABG)
surgeries performed on patients ⬎ 65
years old has risen dramatically over the past decade.1 Studies have shown this procedure to be
effective in relieving angina2 and providing meaningful improvement in functional capacity3 in this population. Elderly patients have been shown to have
*From the Carolinas Medical Center (Drs. Norton, Ramp, Fedor,
Kiebzak, and Cook, and Ms. Pierson), Charlotte, NC; and
Department of Human Nutrition, Foods, and Exercise (Mr.
Pierson and Dr. Herbert), Virginia Tech, Blacksburg, VA.
This study was supported by The Health Sciences Foundation,
Charlotte, NC, and The Heineman Medical Research Foundation, Charlotte, NC.
Manuscript received April 23, 2002; revision accepted August 28,
2002.
Reproduction of this article is prohibited without written permission from the American College of Chest Physicians (e-mail:
[email protected]).
Correspondence to: Lee M. Pierson, MS, 215 War Memorial Hall,
Blacksburg, VA 24061; e-mail: [email protected]
longer postoperative lengths of stay in the hospital
after CABG surgery as well as higher postsurgical
complication rates when compared to younger patients.4 Elderly patients have low physical reserves
and may require more time to regain functional
abilities than younger patients after surgery. In
addition to age, other factors such as gender, comorbid disease conditions, and postoperative exercise
may influence recovery patterns. This study was
conducted to prospectively evaluate the effects of
these factors on the recovery of self-reported functional capacity after CABG surgery and to identify
predictors of functional capacity 1 year after surgery.
Materials and Methods
Patients
One hundred ninety-eight patients undergoing first-time
CABG surgery at Carolinas Medical Center in Charlotte, NC,
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1367
participated in this study. The study protocol was approved by the
Institutional Review Board of Carolinas Medical Center, and
each subject gave written, informed consent before participation.
Patients were excluded from the study if they were scheduled for
additional surgical procedures, scheduled for a minimally invasive
CABG surgery, had amputated limbs, or had cognitive disorders
that would preclude accurate self-assessment of functional abilities. All patients enrolled in the study were classified into three
age categories: younger age (⬍ 60 years), middle age (60 to 69
years), and older age (ⱖ 70 years).
Data Collection
Self-Reported Functional Capacity: The Veterans Specific
Activity Questionnaire (VSAQ) was used to measure perceptions
of functional ability before surgery, and at 3 months and 1 year
after surgery. The VSAQ consists of a list of activities grouped by
metabolic equivalents (METs), and patients were instructed to
select activities that they could perform with minimal or no
symptoms. Scores generated from the VSAQ have previously
been shown to correlate well with maximal treadmill exercise
capacity.5 All participants in the study completed the VSAQ
before surgery in two ways: (1) patients indicated activities that
they had been able to perform immediately prior to the present
hospital admission (VSAQ score at the time of hospital admission
for CABG surgery), and (2) patients indicated activities they had
been able to perform during the past year before surgery (VSAQ
recall score regarding the year before CABG surgery [VSAQ-Y]),
prior to activity restriction associated with recent onset of
symptoms.
Clinical and Comorbidity Information: Data pertaining to
disease severity, comorbid conditions, clinical history, and New
York Heart Association (NYHA) functional class were collected
by physicians during history and physical examinations. Comorbid conditions were defined as having at least one of the
following: left ventricular ejection fraction ⬍ 35%, COPD, peripheral vascular disease, history of congestive heart failure, or
orthopedic problems that limited activities (use of cane or walker
during daily activities). Information regarding the surgical procedure was recorded by the attending surgeon.
Follow-up Measurements: Patients were contacted by telephone 3 months and 1 year postoperatively to collect information
concerning complications or events that influenced convalescence. Patients were also queried regarding aerobic exercise
habits and were considered to be exercising regularly if they
reported performing aerobic-type activities for at least 30 min,
three times per week. The VSAQ was mailed to patients 3 months
and 1 year after surgery to collect self-reported functional
capacity.
Treadmill Exercise Tolerance: To validate the VSAQ score as a
measure of functional capacity in the setting of this study, 78
patients were evaluated for maximal exercise tolerance on a
treadmill within the year after surgery. Each patient completed
the VSAQ questionnaire immediately prior to the exercise test.
An individualized exercise test protocol was used in which speed
was kept constant at a patient-selected walking pace and grade
was increased continually in a ramp fashion so that workload
increased at a rate of approximately 1 MET per minute. Respiratory gas exchange data were continuously collected using a
metabolic cart (VMAX; SensorMedics; Yorba Linda, CA) and
patients exercised to volitional fatigue or a symptom-limited end
point. Oxygen consumption (V̇o2) values were averaged over 20-s
intervals, and the highest value attained during the test was
recorded as the peak exercise V̇o2 (V̇o2pk).
Statistical Analysis
All statistical analyses were performed using SAS statistical
software (Version 6.12; SAS Institute; Cary, NC). A Pearson
correlation was performed between VSAQ scores and V̇o2pk
values to examine the validity of VSAQ for measuring functional
capacity in this sample. Analysis of variance (ANOVA) was used
to compare mean preoperative VSAQ scores between NYHA
functional classes to examine how well the VSAQ questionnaire
discriminated high vs low functional classes. To test for differences in clinical variables between the age groups at baseline, ␹2
and ANOVA analyses were conducted. ANOVA for repeated
measures was conducted to test VSAQ for change with time.
ANOVA was also used to test for differences in VSAQ recovery
between groups based on age, gender, comorbid conditions, and
exercise. Paired t tests were used to determine whether mean
VSAQ scores for age groups returned to presurgical values after
surgery. Stepwise multiple linear regression was conducted to
identify predictors of 1-year postoperative functional capacity.
Results
Preoperative Characteristics
One hundred ninety-eight patients enrolled in the
study, ages ranging from 44 to 86 years (mean ⫾ SD age,
63.4 ⫾ 9.4 years), with 74 younger patients, 73 middleage patients, and 51 older patients. There were 146 men
and 52 women.
Table 1 presents the preoperative clinical characteristics for patients based on age groups. Older
patients had a lower mean VSAQ-Y score and greater
frequency of peripheral vascular disease, while
younger patients had a greater frequency of smoking
history and hyperlipidemia.
Surgical Outcomes
The short-term surgical outcome of these patients
has been presented elsewhere.6 Briefly, there were 7
operative deaths, a total of 12 deaths by 3 months
after surgery, and a total of 15 deaths by 1 year after
surgery. There were 56 patients with at least one
complication after surgery, with complications defined as follows: reoperation, deep sternal infection,
permanent stroke, mechanical ventilation ⬎ 1 day,
renal failure requiring dialysis, arrhythmia requiring
treatment (including atrial fibrillation), multiorgan
failure, or readmission to hospital within 30 days.
There was an overall postoperative length of hospital
stay of 7.6 ⫾ 6.7 days. There were 2 patients who
were forced to radically modify their lifestyles during
the year following CABG surgery due to leg amputations. These patients were excluded from the
analysis of functional capacity recovery, along with
the 15 deaths, for a total of 17 excluded patients. Of
the remaining 181 patients in the study, 3-month
VSAQ data were available for 140 patients (77%) and
1-year VSAQ data were available for 165 patients
(91%). Data were complete at all time points for 136
patients (75%).
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Clinical Investigations
Table 1—Preoperative Characteristics of Study Patients, Shown by Age Category*
Male gender
Medical history
Recent angina
Previous myocardial infarction
Left main disease
Three-vessel disease
Comorbid conditions
Ejection fraction ⬍ 35%
COPD
Peripheral vascular disease†
Orthopedically limited
History of heart failure
Risk factors
Hypertension
Hyperlipidemia†
Diabetes
History of smoking†
Family history of early CAD
VSAQ
VSAQ-Y†
VSAQ-A
Young Age (n ⫽ 74)
Middle Age (n ⫽ 73)
Older Age (n ⫽ 51)
64 (86)
45 (62)
37 (73)
0.003
65 (88)
43 (58)
5 (7)
53 (72)
65 (89)
38 (52)
4 (5)
52 (71)
39 (77)
20 (39)
5 (10)
36 (71)
0.11
0.11
0.65
0.99
22 (30)
17 (23)
6 (8)
1 (1)
7 (9)
13 (18)
12 (16)
20 (27)
1 (1)
13 (18)
12 (24)
11 (22)
16 (31)
2 (4)
10 (20)
0.24
0.59
0.002
0.53
0.22
42 (57)
59 (80)
28 (38)
63 (85)
51 (69)
53 (74)
42 (58)
37 (51)
48 (66)
42 (58)
36 (71)
34 (67)
16 (31)
29 (57)
30 (59)
0.08
0.01
0.08
0.001
0.31
6.5 ⫾ 2.2
4.1 ⫾ 2.2
5.3 ⫾ 2.1‡
3.7 ⫾ 2.1
5.1 ⫾ 2.0‡
3.7 ⫾ 1.9
p Value
⬍ 0.001
0.40
*Data are presented as No. (%) or mean ⫾ SD. VSAQ-A ⫽ VSAQ score at the time of hospital admission for CABG surgery.
†Statistically significant (p ⬍ 0.05).
‡Significantly different from young group.
Postsurgical Angina
Recovery of Self-Reported Functional Capacity
Of the 198 patients enrolled in the study, 178
patients (89%) had angina during daily activities
before surgery. Of the 165 patients reporting functional capacity information at 1-year follow-up, 162
patients (98%) were angina free during daily activities. There were nine patients (5%) who had chest
discomfort during a treadmill test in the year after
surgery and two patients (1%) who underwent angioplasty for stenosis of a bypass graft.
Age Effects: The progression of mean VSAQ score
as a function of age for the 136 patients with
complete data are shown in Figure 1. There were
significant time (p ⬍ 0.0001) and age (p ⫽ 0.008)
effects, with older patients having lower VSAQ
scores than younger patients. There was also a
time/age interaction (p ⫽ 0.02), indicating different
recovery patterns between the age groups. For
younger patients, paired t tests revealed no significant difference between mean VSAQ-Y score and
3-month postsurgery VSAQ score (p ⫽ 0.72), while
for middle-age and older patients, VSAQ scores at
3 months after surgery were lower than VSAQ-Y
scores (p ⫽ 0.03 and p ⫽ 0.003, respectively). There
was no statistical difference found between mean
VSAQ score at 1 year and mean VSAQ-Y score for
any age group, indicating that all age groups returned to presymptomatic functional capacities by
1 year after surgery.
Validity of VSAQ Questionnaire
NYHA functional class was recorded preoperatively for 185 patients in this sample. When preoperative VSAQ scores were analyzed according to
NYHA functional class, mean VSAQ scores decreased systematically over the NYHA functional
classes as follows: mean VSAQ for class I (n ⫽ 3) was
5.3 ⫾ 0.6 METs, mean VSAQ for class II (n ⫽ 23)
was 4.4 ⫾ 2.6 METs, mean VSAQ for class III
(n ⫽ 113) was 4.0 ⫾ 2.0 METs, and mean VSAQ for
class IV (n ⫽ 46) was 3.2 ⫾ 2.0 METs (ANOVA
p ⫽ 0.048).
There were 78 patients who completed both the
VSAQ and a maximal graded exercise test within the
year after surgery. Scores on the VSAQ ranged from
3 to 11 METs and V̇o2pk scores from the treadmill
test ranged from 12.7 to 34.6 mL/kg/min (3.6 to 9.9
METs). The correlation coefficient between VSAQ
score and treadmill V̇o2pk was r ⫽ 0.66 (r2 ⫽ 0.44,
p ⬍ 0.001).
Gender Effects: Figure 2 shows mean VSAQ
scores as a function of gender. There were significant
group (p ⫽ 0.0001) and time (p ⫽ 0.0001) effects,
with male subjects having higher scores than female
subjects. There was no gender/time interaction, indicating no difference in recovery pattern between
the sexes.
Comorbidity Effects: Figure 3 shows mean VSAQ
scores as a function of comorbidity status. Significant
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Figure 1. Mean VSAQ scores as a function of age. Data are presented as mean values; error bars
represent SE. YBS ⫽ year before surgery; ADMIT ⫽ time of admission to hospital; 3 MOS ⫽ 3 months
after surgery; 1 YEAR ⫽ 1 year after surgery.
time (p ⫽ 0.0001) and group (p ⫽ 0.0009) effects
were found. Patients with at least one comorbidity
had a lower mean VSAQ-Y score, as well as lower
3-month and 1-year scores, than patients without a
comorbid condition.
Exercise Effects: There were 55 patients (40%)
who reported performing aerobic exercise at least
3 d/wk for 30 min at the 3-month and 1-year
postsurgery intervals. Figure 4 shows mean VSAQ
scores for these subjects vs patients not reporting
this level of physical activity. Significant time
(0.0001) and group (p ⫽ 0.0001) effects were found,
as well as a trend for a group/time interaction
(p ⫽ 0.096). The group reporting exercise 3 d/wk
had higher VSAQ scores before and after surgery
than patients not reporting this level of activity.
Prediction of 1-Year VSAQ Score
Table 2 presents a summary of the multiple linear
regression performed to identify predictors of 1-year
VSAQ score. The amount of variance explained by
Figure 2. Mean VSAQ scores as a function of gender. Data are presented as mean values; error bars
represent SE. See Figure 1 legend for definition of abbreviations.
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Clinical Investigations
Figure 3. Mean VSAQ scores as a function of comorbid conditions. Data are presented as mean
values; error bars represent SE. See Figure 1 legend for definition of abbreviations.
the prediction model was high (r2 ⫽ 0.47). The best
predictor of 1-year functional capacity was VSAQ-Y
followed by postoperative exercise. No other variables were found to be significant predictors of
1-year functional capacity with these variables in the
model.
Discussion
The validity of the VASQ questionnaire has been
studied by Myers et al,7 and was shown to correlate well with maximal exercise workload predicted
from treadmill speed and grade (r ⫽ 0.72) and
moderately well with maximal exercise V̇o2
(r ⫽ 0.58) in 337 patients referred for exercise
testing for clinical reasons. In our sample of
post-CABG patients, the correspondence between
VSAQ and NYHA class was significant, and the
correlation between VSAQ and measured V̇o2
during maximal treadmill exercise was good
(r ⫽ 0.66). These results indicate that the VSAQ
performed well in discriminating between patients
with a high functional capacity vs patients with a
low functional capacity in our study sample.
Figure 4. Mean VSAQ scores as a function of postoperative exercise. Data are presented as mean
values; error bars represent SE. Exercise ⫽ aerobic activity at least 3 d/wk for 30 min per session. See
Figure 1 legend for definition of abbreviations.
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Table 2—Multiple Linear Regression Prediction of
1-Year Self-Reported Functional*
Variables
Coefficient
p Value
VSAQ-Y
Postoperative exercise
Constant
0.66
0.94
1.29
0.0001
0.003
0.001
*VSAQ-Y coded as a continuous variable; postoperative exercise
coded as 1 for self-report of aerobic activity at least 3 d/wk for
30 min per session at 3-months and 1-year postsurgery.
A primary finding of this study was that older
patients have a protracted, but successful recovery
of functional capacity after coronary surgery. Previous research has shown that functional capacity
decreases with age8,9 and that elderly patients have
lower functional capacities than younger patients
before and after coronary surgery.10,11 The present
study supports these findings with a significant
effect of age on VSAQ scores, older patients
having lower scores compared to younger patients.
At the time of hospital admission in the present
study, however, mean VSAQ score was the same
for all age groups, indicative of activity restrictions
due to anginal symptoms immediately prior to
surgery. After surgery, younger patients regained
presymptomatic functional capacity levels by
3 months after surgery and maintained this level at
1 year. In the middle-age and older groups, functional capacity increased modestly by 3 months
after surgery but increased in subsequent months
to match mean VSAQ-Y by 1 year. The long-term
functional outcomes in the present study are in
agreement with a study by Sjoland et al10 that
found similar increases in exercise capacity between elderly and nonelderly patients when measured before and 2 years after surgery. The
present study, however, is the first to our knowledge to document a delayed recovery pattern for
functional capacity in older adults compared to
younger patients. Artinian et al12 found no difference between elderly and nonelderly patients in
ambulation dysfunction, body care, and movement
during the first 6 weeks after bypass surgery.
Barnason et al13 found no effect of age on physical
recovery rate measured by the Medical Outcomes
Study Short-Form 36 questionnaire during the
year after coronary surgery. These studies used
measures of functional status that rely mainly on
low-to-moderate intensity activities for scoring. In
light of these studies, the present findings suggest
that early recovery of low-intensity activities may
occur in older patients at rates comparable with
younger patients; however, a return to more vigorous activities requires a longer recovery period
for older patients.
At baseline, younger patients had a greater
frequency of smoking history and a greater frequency of hyperlipidemia than the middle-age and
older patients. These findings may appear counterintuitive; however, data from the Framingham
Study fail to show the strong relationship between
smoking and coronary artery disease (CAD) in
patients ⬎ 65 years old that is found in younger
patients with CAD.14 Other investigators have
shown a lack of association between hyperlipidemia and CAD-related mortality and morbidity in
the elderly.15 Smoking and hyperlipidemia may
cause premature death in susceptible individuals,
and other smoking-related diseases, such as lung
cancer, may result in a large number of deaths in
the elderly before symptoms of CAD appear. In
the present study population, smoking and hyperlipidemia may have resulted in early need for
surgery or premature death in susceptible individuals, thus selecting them out of our study.
Women in the present study were found to have
lower VSAQ scores than men, both before and after
surgery. Previous studies have shown that women
have more ambulation dysfunction16 and greater
amounts of physical disability after surgery than
men,17 as well as lower levels of daily activities,18
functional status,19 and peak exercise workloads.10
Some authors have attributed this disparity to technically better revascularization in males.17,18 The
present study, with the inclusion of the VSAQ-Y
measure, shows that at least part of the gender
difference in postsurgical functional capacity results
from gender differences present before surgery.
Other studies supporting the current findings have
reported lower levels of physical functioning,13,20
functional status,19 activities of daily living,21 and
peak exercise workloads10 in women than in men
before CABG surgery. Even though men attained
higher VSAQ scores postoperatively than women in
the present study, these higher scores were related
to higher preoperative scores, and were not a consequence of different recovery patterns between the
sexes.
Patients in the present study who reported
performing postoperative aerobic exercise were
found to have higher functional capacities than
nonexercising patients both before and after surgery. The most plausible explanation for this link is
that patients who live more active lifestyles before
surgery are more likely to be active in the recovery
period. The trend for accelerated improvement in
the exercise group in the present study agrees with
other studies that have reported aerobic exercise
to enhance functional capacity recovery after coronary surgery in both supervised22 and unsupervised23 settings.
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Clinical Investigations
The best predictor of 1-year functional capacity
was baseline functional capacity during the year
before surgery. Previous studies have reported that
patients with the highest functional levels preoperatively attain the highest functional levels after surgery.24,25 Multiple linear regression also revealed
that performance of aerobic exercise in the recovery
period added valuable predictive information when
presurgical functional capacity is already considered
in the model. The positive coefficient for exercise
training indicates that when patients have the same
presurgical functional capacity, those who exercise
will achieve a higher 1-year functional capacity. This
fact is especially important for elderly patients who
have lower functional capacities before surgery and
may wish to optimize functional capacity during the
recovery period.
In summary, the data reported in this study indicate that older patients require more recovery time
after surgery to regain functional capacity than
younger patients. Nevertheless, older patients possess the ability to successfully regain presymptomatic
functional capacity by 1 year after surgery. Functional capacity during the year prior to surgery and
performance of postsurgical exercise are key predictors of 1-year postsurgical functional capacity, regardless of age.
Appendix
The VSAQ
Draw one line below the activities you are able to do routinely
with minimal or no symptoms, such as shortness of breath, chest
discomfort, and fatigue.
METs
1. Eating, getting dressed, working at a desk
2. Taking a shower
Walking down eight steps
3. Walking slowly on a flat surface for one or two blocks
A moderate amount of work around the house, like vacuuming, sweeping the floors or carrying groceries
4. Light yard work, ie, raking leaves, weeding or pushing a
power mower
Painting or light carpentry
5. Walking briskly, ie, four miles in 1 h
Social dancing, washing the car
6. Play nine holes of golf carrying your own clubs
Heavy carpentry, mow lawn with push mower
7. Perform heavy outdoor work, ie, digging, spading soil, etc
Play tennis (singles), carry 60 lb
8. Move heavy furniture
Jog slowly, climb stairs quickly, carry 20 lb upstairs
9. Bicycling at a moderate pace, sawing wood, jumping rope
(slowly)
10. Brisk swimming, bicycle up a hill, walking briskly uphill, jog
six miles per hour
11. Cross country skiing
Play basketball (full court)
12. Running briskly, continuously (level ground, 8 min per mile)
13. Any competitive activity, including those which involve intermittent sprinting
Running competitively, rowing, backpacking
References
1 Aziz S, Grover FL. Cardiovascular surgery in the elderly.
Cardiol Clin 1999; 17:213–231
2 Morgan JM, Gray HH, Clague JC, et al. Coronary arterial
surgery in the elderly: its effect in the relief of angina. Int
J Cardiol 1989; 23:327–333
3 Jaeger AA, Hlatky MA, Paul SM, et al. Functional capacity
after cardiac surgery in elderly patients. J Am Coll Cardiol
1994; 24:104 –108
4 Roberts AJ, Woodhall DD, Conti CR, et al. Mortality,
morbidity, and cost-accounting related to coronary artery
bypass graft surgery in the elderly. Ann Thorac Surg 1985;
39:426 – 432
5 Myers J, Do D, Herbert W, et al. A nomogram to predict
exercise capacity from a specific activity questionnaire and
clinical data. Am J Cardiol 1994; 73:591–596
6 Cook JW, Pierson LM, Herbert WG, et al. The influence of
patient strength, aerobic capacity and body composition upon
outcomes after coronary artery bypass grafting. Thorac Cardiovasc Surg 2001; 49:89 –93
7 Myers J, Bader D, Madhavan R, et al. Validation of a specific
activity questionnaire to estimate exercise tolerance in patients referred for exercise testing. Am Heart J 2001; 142:
1041–1046
8 Dehn MM, Bruce RA. Longitudinal variations in maximal
oxygen intake with age and activity. J Appl Physiol 1972;
33:805– 807
9 Astrand I. Aerobic work capacity in men and women with
special reference to age. Acta Physiol Scand 1960; 169:
7–92
10 Sjoland H, Wiklund I, Caidahl K, et al. Improvement in
quality of life and exercise capacity after coronary bypass
surgery. Arch Intern Med 1996; 156:265–271
11 Iskandrian AS, Hakki AH. The effects of aging after
coronary arterial bypass grafting on the regulation of
cardiac output during upright exercise. Int J Cardiol 1985;
7:347–360
12 Artinian NT, Duggan C, Miller P. Age differences in patient
recovery patterns following coronary artery bypass surgery.
Am J Crit Care 1993; 2:453– 461
13 Barnason S, Zimmerman L, Anderson A, et al. Functional
status outcomes of patients with a coronary artery bypass graft
over time. Heart Lung 2000; 29:33– 46
14 Castelli WP, Wilson PW, Levy D, et al. Cardiovascular risk
factors in the elderly. Am J Cardiol 1989; 63:12H–19H
15 Krumholz HM, Seeman TE, Merrill SS, et al. Lack of
association between cholesterol and coronary heart disease
mortality and morbidity and all-cause mortality in persons
older than 70 years. JAMA 1994; 272:1335–1340
16 Artinian NT, Duggan CH. Sex differences in patient recovery
patterns after coronary artery bypass surgery. Heart Lung
1995; 24:483– 494
17 Stanton BA, Jenkins CD, Savageau JA, et al. Functional
benefits following coronary artery bypass graft surgery. Ann
Thorac Surg 1984; 37:286 –290
www.chestjournal.org
Downloaded From: http://publications.chestnet.org/pdfaccess.ashx?url=/data/journals/chest/21993/ on 06/16/2017
CHEST / 123 / 5 / MAY, 2003
1373
18 Douglas JS Jr, King SB, Jones EL, et al. Reduced efficacy of
coronary bypass surgery in women. Circulation 1981; 64:
II11–II16
19 Stewart RD, Blair JL, Emond CE, et al. Gender and functional outcome after coronary artery bypass. Surgery 1999;
126:184 –190
20 King KM, Collins-Nakai RL. Short term recovery from
cardiac surgery in women: suggestions for practice. Can
J Cardiol 1998; 14:1367–1371
21 Czajkowski SM, Terrin M, Lindquist R, et al. Comparison of
preoperative characteristics of men and women undergoing
coronary artery bypass grafting (the Post Coronary Artery
Bypass Graft [CABG] Biobehavioral Study). Am J Cardiol
1997; 79:1017–1024
22 Goodman JM, Pallandi DV, Reading JR, et al. Central
and peripheral adaptations after 12 weeks of exercise training
in post-coronary artery bypass surgery patients. J Cardiopulm
Rehabil 1999; 19:144 –150
23 Stevens R, Hanson P. Comparison of supervised and unsupervised exercise training after coronary bypass surgery. Am J
Cardiol 1984; 53:1524 –1528
24 Allen JK, Becker DM, Swank RT. Factors related to functional status after coronary artery bypass surgery. Heart Lung
1990; 19:337–343
25 Guadagnoli E, Ayanian JZ, Cleary PD. Comparison
of patient-reported outcomes after elective coronary artery
bypass grafting in patients aged greater than or equal to and
less than 65 years. Am J Cardiol 1992; 70:60 – 64
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Clinical Investigations