Resident versus Attending Surgeon Patency
and Clinical Outcomes in On- versus OffPump Coronary Artery Bypass Surgery
G Hossein Almassi, MD1
Brendan M. Carr, MS2
Muath Bishawi, MD, MPH3
A. Laurie Shroyer, PhD2
Jacquelyn A. Quin, MD4
Brack Hattler, MD5
Todd H. Wagner, PhD6
Joseph F. Collins, PhD7
Pasala Ravichandran, MD8
Joseph C. Cleveland, MD9
Frederick L. Grover, MD5,9
Faisal G. Bakaeen, MD10
for the VA #517 Randomized On/Off Bypass (ROOBY) Study Group
1Cardiothoracic Surgery, Medical College of Wisconsin and Veterans Affairs (VA) Medical Center, Milwaukee, WI;
2Surgery, Northport VA Medical Center and Stony Brook Medicine School of Medicine, Stony Brook, NY; 3Surgery,
Duke University, Durham, NC; 4Cardiac Surgery, VA Boston Healthcare System, West Roxbury, MA; 5Cardiology,
VA Eastern Colorado Health Care System, Denver, CO; 6VA Palo Alto Health Economics Resource Center, Menlo
Park, CA and Department of Health Research and Policy, Stanford University, Stanford, CA; 7Cooperative Studies
Program Coordinating Center and VA Medical Center, Perry Point, Maryland; 8Surgery, Oregon Health and
Sciences University and Portland VA Medical Center, Portland, OR; 9Surgery, University of Colorado School of
Medicine at the Anschutz Medical Campus, Aurora, CO; 10Cardiothoracic Surgery, Baylor College of Medicine and
Houston VA Medical Center, Houston, TX
Presenter Disclosure
No disclosure to report
Funding
Cooperative Studies Program of the
Department of Veterans Affairs Office of
Research and Development and the
Department of Veterans Affairs Central Office,
Office of Patient Care Services.
Offices of Research and Development at the
Zablocki VA Medical Center, Northport VA
Medical Center, and the VA Eastern Colorado
Healthcare System.
Background
 Residents must be trained to perform cardiac
surgical procedures
 Balance between education and what is best for the
patient
 Prior studies have shown no impact on CABG
clinical outcomes
 Little information about effect on graft patency
Background
 Bakaeen et al., 2012 – residents and attendings had
similar outcomes and 1-year patency
 Bakaeen et al., 2009 – residents had longer
operative times, perfusion and cross-clamp times,
but similar outcomes
 Guo et al., 2008 – residents /fellows vs. consultants
had similar operative morbidity and mortality in onpump CABG
Background
 Haan et al., 2007 – hospitals with residency
programs have longer perfusion times but similar
outcomes
 Asimakopoulos et al., 2006 – residents had similar
operative morbidity and mortality in off-pump CABG
 Ascione et al., 2004 – residents had similar morbidity
and mortality in high-risk off-pump CABG patients
Research Questions
 Do different clinical outcomes result when
residents vs. attendings perform the
majority of distal coronary anastomoses?
 Do grafts performed during CABG by
residents vs. attendings have different
rates of patency at 1 year postop?
 Are these results different for on-pump vs.
off-pump CABG?
ROOBY Trial
 VA Cooperative Study (18 centers)
 February 2002 – May 2008
 Prospective, randomized, single-blinded
 Comparison of CABG with and without
CPB
 ONCAB (n = 1,099)
 OPCAB (n = 1,104)
 Total (n = 2,203)
Study Population
 All patients = 1,272
 16 centers with cardiac surgery residents
 Data on resident anastomoses captured
beginning July 2003
 OPCAB = 639 Patients
 Resident as primary surgeon: 431 (67.4%)
 ONCAB = 633 Patients
 Resident as primary surgeon: 493 (77.9%)
Definition
 Primary surgeon:
 The individual (resident or attending) who
performed ≥ 50% of the distal anastomoses
in a given patient
Clinical Outcomes
 Short-term (30-day) composite endpoint:







Death
Reoperation
New mechanical support
Cardiac arrest
Coma
Stroke
Renal failure requiring dialysis
 1-year composite endpoint:
 Death from any cause within 1 year after surgery
 Nonfatal myocardial infarction between 30 days and 1 year
 Any revascularization procedure between 30 days and 1 year
Graft Patency
 Coronary angiography at 1 year postop
 FitzGibbon classification
 A = An excellent/unimpaired graft
 B = An impaired graft with a stenosis >50%
reducing the caliber of the graft to <50% of
the target artery diameter
 O = A completely occluded graft
Statistical Methods
 Discrete variables: Chi-square or Fisher
Exact tests
 Continuous variables: Student T-tests
 Multivariate Regression
 Significance at p < 0.01 for all ROOBY
sub-studies
Results
Baseline patient characteristics
Patient risk profile
On-pump
N=633
Off-pump
N=639
Resident
n/N (%)
Attending
n/N (%)
p-value
Resident
n/N (%)
Attending
n/N (%)
p-value
119/493 (24.1)
20/140 (14.3)
0.013
89/431 (20.6)
44/208 (21.2)
0.88
Creatinine > 1.5 mg/dl
30/493 (6.1)
14/140 (10.0)
0.11
38/431 (8.8)
17/208 (8.2)
0.79
Cerebrovascular accident
31/493 (6.3)
13/140 (9.3)
0.22
26/431 (6.0)
14/208 (6.7)
0.73
Peripheral artery disease
61/493 (12.4)
18/140 (12.9)
0.88
65/431 (15.1)
40/208 (19.2)
0.18
Diabetes
233/493 (47.3)
63/140 (45.0)
0.64
202/431 (46.9)
82/208 (39.4)
0.08
Hypertension
424/493 (86.0)
128/140 (91.4)
0.09
374/431 (86.8)
180/208 (86.5)
0.93
10/493 (2.0)
2/140 (1.4)
0.65
14/429 (3.3)
11/208 (5.3)
0.22
COPD
Atrial fibrillation
LVEF by category
< 35%
≥ 35%
0.64
23/485 (4.7)
462/485 (95.3)
5/132 (3.8)
127/132 (96.2)
Prior MI
142/490 (29.0)
39/138 (28.3)
β-Blocker Use
302/493 (61.3)
Aspirin
Urgent case
0.05
19/419 (4.5)
400/419 (95.5)
17/201 (8.5)
184/201 (91.5)
0.87
116/427 (27.2)
63/208 (30.3)
0.41
83/140 (59.3)
0.67
275/431 (63.8)
127/208 (61.1)
0.50
411/493 (83.4)
119/140 (85.0)
0.64
370/431 (85.8)
168/208 (80.8)
0.10
60/493 (12.2)
16/140 (11.4)
0.81
62/431 (14.4)
27/208 (13.0)
0.63
Coronary territories and anastomoses per
primary surgeon
On-pump
N=633
Coronary anatomy
Territories with
disease
1
2
3
Off-pump
N=639
Resident
n/N (%)
Attending
n/N (%)
p-value
Resident
n/N (%)
Attending
n/N (%)
p-value
34/493 (6.9)
133/493 (27.0)
322/493 (65.3)
9/140 (6.4)
31/140 (22.1)
100/140 (71.4)
0.43
34/431 (7.9)
132/431 (30.6)
263/431 (61.0)
11/207 (5.3)
61/207 (29.5)
132/207 (63.8)
0.35
Distals performed by
Resident only
Attending only
Both
303/633 (47.9)
121/633 (19.1)
209/633 (33.0)
*NOTE: p-value is for the comparison between treatment groups
269/639 (42.1)
168/639 (26.3)
202/639 (31.6)
0.008*
Comparison of target vessels quality based on who actually
performed the anastomoses
On-pump
n/N (%) OR mean ± SD
Resident
Attending
Off-pump
n/N (%) OR mean ± SD
p-value
Resident
Attending
p-value
414/443 (93.5)
29/443 (6.5)
159/179 (88.8)
20/179 (11.2)
0.05
62/69 (89.9)
7/69 (10.1)
0.75
196/211 (92.9)
15/211 (7.1)
0.51
28/30 (93.3)
2/30 (6.7)
0.38
46/52 (88.5)
6/52 (11.5)
0.21
130/142 (91.5)
12/142 (8.5)
0.48
LAD anastomoses
Quality of target
Good/Moderate
Poor
450/482 (93.4)
32/482 (6.6)
Quality of target
Good/Moderate
Poor
164/176 (93.2)
12/176 (6.8)
Quality of target
Good/Moderate
Poor
304/331 (91.8)
27/331 (8.2)
Quality of target
Good/Moderate
Poor
40/45 (88.9)
5/45 (11.1)
Quality of target
Good/Moderate
Poor
43/47 (91.5)
4/47 (8.5)
Quality of target
Good/Moderate
Poor
134/156 (85.9)
22/156 (14.1)
Quality of target
Good/Moderate
Poor
21/23 (91.3)
2/23 (8.7)
118/136 (86.8)
0.01
18/136 (13.2)
Diagonal anastomoses
48/51 (94.1)
0.81
114/129 (88.4)
3/51 (5.9)
15/129 (11.6)
Circumflex (AV) / OM anastomoses
130/145 (89.7)
0.44
15/145 (10.3)
Ramus anastomoses
207/227 (91.2)
20/227 (8.8)
15/18 (83.3)
0.55
40/41 (97.6)
3/18 (16.7)
1/41 (2.4)
Right main coronary anastomoses
36/40 (90.0)
0.81
4/40 (10.0)
PDA anastomoses
56/59 (94.9)
3/59 (5.1)
126/151 (83.4)
0.55
113/127 (89.0)
25/151 (16.6)
14/127 (11.0)
Posterolateral anastomoses
0.22
14/18 (77.8)
14/14 (100.0)
4/18 (22.2)
0/14 (0.0)
0.37
17/18 (94.4)
1/18 (5.6)
Operative variables by primary surgeon
Patients operative profile
On-pump
N=633
Off-pump
N=639
Resident
n/N (%)
Attending
n/N (%)
p-value
Resident
n/N (%)
Attending
n/N (%)
p-value
Units of packed RBC
1.0 ± 1.6
(n=493)
0.9 ± 1.6
(n=140)
0.89
1.0 ± 1.5
(n=430)
1.0 ± 1.6
(n=208)
0.65
Units of fresh frozen
plasma
0.4 ± 1.1
(n=493)
0.5 ± 1.4
(n=140)
0.51
0.5 ± 1.3
(n=430)
0.5 ± 1.3
(n=208)
0.73
0.3 ± 1.5
(n=493)
14/493 (2.8)
0.1 ± 0.6
(n=140)
6/140 (4.3)
0.03
0.4 ± 1.7
(n=430)
17/431 (3.9)
0.4 ± 1.5
(n=208)
5/208 (2.4)
0.96
Units of platelets
Take down and redo of
distal
0.39
0.32
Short-term Clinical Outcomes
On-pump
n/N (%) OR mean ± SD
Resident
Attending
Short-term composite*
24/493 (4.9)
10/140 (7.1)
Reoperation for bleeding
9/493 (1.8)
Stroke
Renal failure requiring
dialysis
Prolonged vent >48hrs
Resident
Attending
p-value
0.29
27/431 (6.3)
10/208 (4.8)
0.46
4/140 (2.9)
0.45
14/431 (3.2)
4/208 (1.9)
0.34
3/493 (0.6)
2/140 (1.4)
0.33
3/431 (0.7)
2/208 (1.0)
0.72
2/493 (0.4)
0/140 (0.0)
0.45
3/431 (0.7)
2/208 (1.0)
0.72
15/493 (3.0)
6/140 (4.3)
0.47
21/431 (4.9)
9/208 (4.3)
0.76
Re-intubation
13/493 (2.6)
5/140 (3.6)
0.56
16/429 (3.7)
5/208 (2.4)
0.38
MI
18/493 (3.7)
4/140 (2.9)
0.65
25/431 (5.8)
12/208 (5.8)
0.99
New mechanical sup.
5/493 (1.0)
1/140 (0.7)
0.75
5/431 (1.2)
4/208 (1.9)
0.44
Mediastinitis
4/493 (0.8)
4/140 (2.9)
0.06
3/431 (0.7)
5/208 (2.4)
0.07
Operative Death
3/493 (0.6)
2/140 (1.4)
0.33
5/431 (1.2)
1/208 (0.5)
0.40
7.6 ± 5.3
(n=486)
8.1 ± 6.8
(n=139)
0.43
7.6 ± 4.4
(n=425)
7.9 ± 5.6
(n=203)
0.53
Hospital length of stay
(days)
p-value
Off-pump
n/N (%) OR mean ± SD
* Short-term composite endpoint included death, reoperation, new mechanical support, cardiac arrest,
coma, stroke, or renal failure requiring dialysis before discharge or within 30 days after surgery
1-Year Clinical Outcomes
On-pump
n/N (%) OR mean ± SD (n)
Off-pump
n/N (%) OR mean ± SD (n)
Resident
Attending
p-value
Resident
Attending
p-value
1-year composite*
32/493 (6.5)
8/140 (5.7)
0.74
44/431 (10.2)
19/208 (9.1)
0.67
All-cause death
12/493 (2.4)
4/140 (2.9)
0.78
17/431 (3.9)
5/208 (2.4)
0.32
Repeat
revascularization†
16/493 (3.2)
4/140 (2.9)
0.82
25/431 (5.8)
11/208 (5.3)
0.79
Non-fatal MI†
8/493 (1.6)
2/140 (1.4)
0.87
5/431 (1.2)
4/208 (1.9)
0.44
*1-year composite endpoint included death from any cause within 1 year after surgery,
nonfatal myocardial infarction between 30 days and 1 year, and any revascularization
procedure between 30 days and 1 year
† These two late adverse outcomes were evaluated from the time of 30-days post-surgery up
until 1-year follow-up
1-Year FitzGibbon Patency
On-pump
Resident
n/N (%)
Overall
A
B
O
SVG
A
B
O
LIMA
A
B
O
Attending
n/N (%)
Off-pump
p-value
Resident
n/N (%)
Attending
n/N (%)
0.72
590/711 (83.0) 262/318 (82.4)
23/711 (3.2)
8/318 (2.5)
98/711 (13.8) 48/318 (15.1)
0.94
491/636 (77.2) 328/428 (76.6)
27/636 (4.2)
20/428 (4.7)
118/636 (18.6) 80/428 (18.7)
0.81
314/414 (75.8) 178/228 (78.1)
15/414 (3.6)
8/228 (3.5)
85/414 (20.5) 42/228 (18.4)
0.51
260/369 (70.5) 213/294 (72.4)
12/369 (3.3)
13/294 (4.4)
97/369 (26.3) 68/294 (23.1)
0.42
253/268 (94.4)
6/268 (2.2)
9/268 (3.4)
71/74 (95.9)
0/74 (0.0)
3/74 (4.1)
p-value
0.78
219/247 (88.7)
14/247 (5.7)
14/247 (5.7)
99/112 (88.4)
5/112 (4.5)
8/112 (7.1)
A = An excellent/unimpaired graft
B = An impaired graft with a stenosis >50% reducing the caliber of the graft to <50% of the target artery diameter
O = A completely occluded graft
SVG = Saphenous vein graft
LIMA = Left internal mammary artery
Limitations
 Attendings could have assisted residents




in ways not documented
Predominantly male veteran population
Subgroup analysis
Resident anastomosis data not captured
during first year of ROOBY trial
Follow-up limited to 1 year
Conclusions

For ROOBY Trial patients:
 No difference in perioperative
outcomes
 No difference in 1-year outcomes
 No difference in 1-year graft
patency
Conclusion
Residents can and should be trained in
advanced surgical techniques with no
negative impact on surgical outcomes.
Thank You