Practice Patterns and Clinical Outcomes After Hybrid Coronary

Cardiovascular Surgery
Practice Patterns and Clinical Outcomes After Hybrid
Coronary Revascularization in the United States
An Analysis From the Society of Thoracic Surgeons Adult
Cardiac Database
Ralf E. Harskamp, MD; J. Matthew Brennan, MD, MPH; Ying Xian, MD, PhD;
Michael E. Halkos, MD, MS; John D. Puskas, MD, MS; Vinod H. Thourani, MD; James S. Gammie, MD;
Bradley S. Taylor, MD; Robbert J. de Winter, MD, PhD; Sunghee Kim, PhD; Sean O’Brien, PhD;
Eric D. Peterson, MD, MPH; Jeffrey G. Gaca, MD
Background—Hybrid coronary revascularization (HCR) involves a combination of surgical and percutaneous techniques,
which in selected patients may present an alternative to conventional coronary artery bypass grafting (CABG).
Methods and Results—Patients were included who underwent HCR (staged/concurrent) or isolated CABG in the Society
of Thoracic Surgeons Adult Cardiac Surgery Database (July 2011 to March 2013). HCR represented 0.48% (n=950;
staged=809, concurrent=141) of the total CABG volume (n=198 622) during the study period, and was performed in onethird of participating centers (n=361). Patients who underwent HCR had higher cardiovascular risk profiles in comparison
with patients undergoing CABG. In comparison with CABG, median sternotomy (98.5% for CABG, 61.1% for staged
HCR, and 52.5% for concurrent HCR), direct vision harvesting (98.9%, 66.0%, and 68.1%) and cardiopulmonary bypass
(83.4%, 45%, and 36.9%) were less frequently used for staged and concurrent HCR, whereas robotic assistance (0.7%,
33.0%, and 30.5%) was more common. After adjustment, no differences were observed for the composite of in-hospital
mortality and major morbidity (odds ratio, 0.93; 95% confidence interval, 0.75–1.16; P=0.53 for staged HCR, and odds
ratio, 0.94; 95% confidence interval, 0.56–1.56; P=0.80 for concurrent HCR in comparison with CABG). There was
no statistically significant association between operative mortality and either treatment group (odds ratio, 0.74; 95%
confidence interval, 0.42–1.30; P=0.29 for staged HCR, and odds ratio, 2.26; 95% confidence interval, 0.99–5.17;
P=0.053 for concurrent HCR in comparison with CABG).
Conclusion—HCR, either as a staged or concurrent procedure, is performed in one-third of US hospitals and is reserved
for a highly selected patient population. Although HCR may appear to be an equally safe alternative for CABG surgery,
further randomized study is warranted. (Circulation. 2014;130:872-879.)
Key Words: coronary artery bypass ◼ coronary disease ◼ stents ◼ thoracic surgery
H
ybrid coronary revascularization (HCR), which involves
the combined use of percutaneous and surgical techniques, has emerged as an alternative to conventional coronary artery bypass grafting (CABG) for selected patients
with multivessel coronary disease.1–3 In most cases, HCR
involves a surgical procedure in which the internal mammary
artery (IMA) is grafted to the left anterior descending (LAD)
coronary artery, preceded or followed by percutaneous coronary intervention (PCI) of non-LAD coronary lesions, either
Editorial see p 869
Clinical Perspective on p 879
performed in 1 setting (concurrent) or as a staged procedure.4
A prerequisite for HCR is that the patient has LAD anatomy
that is eligible for surgical revascularization, but also has nonLAD lesions that are amenable for PCI. The concept of HCR
stems from the hypothesis that (1) bypass grafting of the LAD
with an IMA graft is superior to coronary stenting, and (2) PCI
with the latest drug-eluting stents is equal or even superior
to other bypass grafts used for non-LAD disease.5,6 Advances
in surgical techniques also allowed IMA-to-LAD grafting to
be performed by using less invasive techniques than conventional CABG. Although several reports suggested a reduction in perioperative morbidity, length of intensive care and
Continuing medical education (CME) credit is available for this article. Go to http://cme.ahajournals.org to take the quiz.
Received February 13, 2014; accepted June 20, 2014.
From the Duke Clinical Research Institute and Duke University Medical Center, Durham NC (R.E.H., J.M.B., Y.X., S.K., S.O'B., E.D.P., J.G.G.);
Academic Medical Center of the University of Amsterdam, Amsterdam, Netherlands (R.E.H., R.J.d.W.); Cardiothoracic Surgery Clinical Research Unit,
Division of Cardiothoracic Surgery, Emory University School of Medicine, Atlanta, GA (M.E.H., V.H.T); Department of Cardiothoracic Surgery, Mount
Sinai Beth Israel, New York, NY (J.D.P.); and Heart Center of the University of Maryland Medical Center, Baltimore, MD (J.S.G., B.S.T.).
Correspondence to Ralf E Harskamp, MD, Duke Clinical Research Institute, 2400 Pratt St, Durham, NC 27705. Email [email protected]
© 2014 American Heart Association, Inc.
Circulation is available at http://circ.ahajournals.org
DOI: 10.1161/CIRCULATIONAHA.114.009479
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872
Harskamp et al Hybrid Revascularization in the United States 873
hospital stay, with equal left IMA patency, these studies have
generally been limited to a small number of high-volume centers with experienced operators.3,4,7 It is unknown the degree
to which HCR is used in routine clinical practice in the United
States, and the clinical characteristics or in-hospital outcomes
of patients who undergo HCR, as well.
To address this paucity of information, we performed a contemporary examination of HCR among isolated CABG procedures by using data from the Society of Thoracic Surgeons
(STS) national registry. The objectives of this study were
3-fold: (1) to describe the incidence and variation of HCR, and
HCR characteristics among US centers, as well; (2) to assess
and compare clinical and operative characteristics between
HCR and conventional CABG; (3) to describe and compare
in-hospital outcomes between HCR and conventional CABG.
Methods
Study Population
From the STS adult cardiac database version 2.73 we included
patients that were enrolled from July 2011 through March 2013.
From this starting population, we included patients who underwent a
hybrid procedure or isolated CABG, and applied a number of exclusion criteria, which are listed in Figure 1.
Procedural Definitions and Outcomes
In our study, HCR was considered a planned procedure that included
the use of an IMA graft and coronary stent placement that could either
be performed concurrently or as a 2-stage procedure performed during the same hospitalization. Other variable definitions followed the
standards of the Society of Thoracic Surgeons Adult Cardiac Surgery
Database data version 2.73 (http://www.sts.org). The primary outcome was in-hospital mortality or major morbidity, a composite of
(peri)operative mortality, the need for reoperation (for bleeding/
tamponade, valvular dysfunction, graft occlusion, or other cardiac
reasons), stroke, renal failure, mediastinitis, or prolonged ventilation.
The secondary outcomes were the individual components of the composite end point, and postoperative length of hospital stay.
Statistical Analysis
The incidence of HCR in the study population was presented as a
median, interquartile range, minimum and maximum. Variation in the
incidence among US hospitals was assessed by histograms, sorted
from largest to smallest percentage of HCR use, to graphically display hospital variation. Temporal trends of hospital rates of HCR
among the study population were calculated by 3-month intervals
during the study period.
Clinical and procedural characteristics were displayed in descriptive tables, in which continuous variables are summarized as median
and interquartile range, and categorical variables as percentage and
frequency counts between parentheses. P values for comparing the
distribution of variables among the comparison groups was computed
with the χ2 test for categorical variables and the Kruskal-Wallis test
for continuous variables.
In-hospital outcomes including the composite end point of mortality and major morbidity were presented as odds ratios (ORs) and 95%
confidence intervals (CIs) and P values with adjusting for potential
confounders using logistic regression with the generalized estimating equations (to account for the correlation in the same site) for the
composite end point and for operative mortality. Potential confounders were based on previously developed and validated STS CABG
mortality model.8
The following variables were included in the adjustment model:
CABG volume, age, race, sex, diabetes mellitus, hypertension, cerebrovascular disease, peripheral vascular disease, dialysis, immunocompromised status, creatinine, chronic lung disease, body surface
area, ejection fraction, congestive heart failure, unstable angina,
previous myocardial infarction, recent myocardial infarction (<21
days, 6–24 hours, <6 hours), atrial fibrillation, preoperative intraaortic balloon pump, acuity status, inotropes, number of diseased
vessels, left main disease and valvular disease, and previous cardiac
surgery. Missing variables were imputed by using the most common
category for categorical variables and group-specific medians for
continuous variables with the exception of outcomes. All continuous variables were tested for linearity, and nonlinear relationships
were accounted for by using flexible spines including linear splines
or quadratic polynomial. For postoperative length of stay, we presented median, interquartile range, and P value, using linear regression with generalized estimating equations. A P value of <0.05 was
considered statistically significant. The study protocol has been
reviewed and approved by the Duke University Health System institutional review board, and informed consent was waived. All statistical tests were performed by the Duke Clinical Research Institute,
Durham, NC, with the use of SAS 9.3 (SAS Institute, Cary, NC).
Results
Incidence, Variation, and Temporal Trends of HCR
Among US Hospitals
Figure 1. Flow chart of study population. CABG indicates
coronary artery bypass grafting; HCR, hybrid coronary
revascularization; IMA, internal mammary artery; PCI,
percutaneous coronary intervention; and STEMI, ST-segment
elevation myocardial infarction.
Among 198 622 patients with multivessel disease who underwent isolated CABG surgery, 950 patients underwent either
staged or concurrent HCR between July 2011 and March
2013. These patients represented 0.48% of the total CABG
volume over this period. Of the 1050 hospitals that performed
isolated CABG, 361 (34.4%) hospitals performed at least
1 HCR, of whom 322 (30.7%) performed at least 1 staged
HCR and 83 (7.9%) performed at least 1 concurrent HCR
in this period. The annual CABG volume of hospitals that
performed at least 1 staged HCR was higher (median, 143;
25th to 75th percentile, 83–232) in comparison with centers
that performed at least 1 concurrent HCR procedure (median,
120; 25th to 75th percentile, 79–232) or no HCR procedures
(median, 128; 25th to 75th percentile, 75–210; P=0.0005).
The distribution of percentage of HCR use (staged and concurrent) among hospitals is shown in Figure 2. The median
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874 Circulation September 9, 2014
Figure 3. Recent temporal trends in the use of hybrid coronary
revascularization. CABG indicates coronary artery bypass
grafting; and HCR, hybrid coronary revascularization.
of HCR over the measured time period (P=0.42). Hospital
characteristics associated with the use of HCR, included the
availability of surgeons who performed less invasive, sternalsparing CABG procedures. In these centers, the use of staged
or concurrent HCR was significantly higher than in centers
that did not perform minimally invasive procedures (median
[%], 0.22 versus 0.0, P<0.0001).
Presenting Features and Clinical Characteristics
Figure 2. Hospital variation in the use of HCR among US sites
that performed at least 1 hybrid procedure. Displayed is the
hospital variation in the use of HCR procedures (as a percentage
of total CABG volume) among hospitals that performed at
least 1 hybrid procedure. Top, this variation in use is shown
when considering all HCR procedures. Middle, staged HCR
procedures. Bottom, of concurrent HCR procedures only. CABG
indicates coronary artery bypass grafting; and HCR, hybrid
coronary revascularization.
percentage of use of HCR among hospitals that performed
at least 1 HCR was 0.76% and an interquartile range of 0.44
to 1.54. The maximum percentage of HCR use was ≈13%
of total CABG volume. The largest number of HCR cases
performed per site during the study period was 54. We also
assessed the percentage of HCR use per quarter, as shown
in Figure 3. No temporal trend could be observed in the use
The clinical characteristics are displayed in Table 1. Overall,
in comparison with patients who underwent conventional
CABG, patients who underwent staged or concurrent HCR
more frequently presented with non–ST-segment elevation
myocardial infarction (23.7%, 32.8%, and 34.8%), more frequently had a history of myocardial infarction (47.0%, 63.0%,
and 58.2%), had previous PCI (25.3%, 59.0%, and 50.4%),
and were more frequently on dialysis (4.8%, 6.8%, and 8.5%).
Patients who underwent concurrent HCR, also more frequently had peripheral vascular disease (14.4%, 14.5%, and
16.3%) and a history of stroke (7.3%, 7.1%, and 10.6%) in
comparison with the other groups. Other cardiovascular risk
factors, such as hypertension, diabetes mellitus, and dyslipidemia were comparable. At coronary angiography, patients
undergoing HCR has less significant left main coronary
involvement and 3-vessel disease.
Continuation of dual-antiplatelet therapy was more frequent among patients who underwent staged or concurrent
HCR, as is illustrated by the recent use of ADP inhibitor (<5
days) which was 25.2% and 27.0% after staged and concurrent HCR, respectively, versus 11.3% in the conventional
CABG group. Also, the use of glycoprotein IIb/IIIa inhibitors
was higher in the HCR groups than in patients undergoing
CABG (2.0%, 10.8%, and 5.0%).
Operative Characteristics
Among patients who underwent staged HCR, surgical revascularization was performed first in 540 patients (66.8%), and
PCI was performed first in 269 patients (33.2%). In the concurrent HCR group, surgical revascularization also occurred
first in the majority of cases (70.2%). As shown in Table 2,
the operative approach in the HCR groups more frequently
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Harskamp et al Hybrid Revascularization in the United States 875
Table 1. Patient and Angiographic Characteristics
Isolated CABG
(n=197 672)
Age, y
65 (58–73)
Staged HCR
(n=809)
65 (57–73)
Table 2. Operative Characteristics
Concurrent HCR
(n=141)
65 (59–72)
Isolated CABG
(n=197 672)
Elective
Male
74.83 (147 919)
71.9 (582)
75.9 (107)
Operative approach
White
81.3 (160 795)
78.2 (633)
76.6 (108)
Full sternotomy
BMI, kg/m2
29.1 (25.9–33.1) 28.7 (25.6–32.9) 28.7 (25.4–34.5)
Partial sternotomy
Diabetes mellitus
46.1 (91 062)
44.0 (62)
Parasternal incision
45.1 (365)
42.2 (83 390)
Staged HCR
(n=809)
Concurrent HCR
(n=141)
44.1 (357)
50.4 (71)
98.5 (194 704)
61.1 (494)
52.5 (74)
0.34 (665)
0.87 (7)
0.04 (84)
0.99 (8)
4.3 (6)
1.4 (2)
Current smoker
21.7 (42 908)
22.6 (183)
21.3 (30)
Lateral thoracotomy
Dyslipidemia
87.4 (172 802)
88.9 (719)
83.7 (118)
Minimally invasive
0.43 (841)
18.5 (150)
27.0 (38)
Family history of
CAD
28.7 (56 709)
24.4 (197)
21.3 (30)
Planned as OPCAB
17.2 (34 029)
55.8 (451)
63.1 (89)
OPCAB as treated
16.6 (32 833)
55.0 (445)
63.1 (89)
Hypertension
88.3 (174}476)
87.4 (707)
85.8 (121)
Time on CPB, min
7.3 (14 337)
7.1 (57)
10.6 (15)
Skin incision time, min
225 (183–275) 199 (154–253)
226 (163–278)
14.4 (28 423)
14.5 (117)
16.3 (23)
Time in OR, min
301 (253–359) 287 (237–344.5)
307 (241–390)
Previous stroke
PVD
0.5 (972)
18.3 (148)
14.9 (21)
91 (71–115)
83.5 (62–112)
88 (60–110)
Dialysis
4.8 (9390)
6.8 (55)
8.5 (12)
IMA harvest technique
Creatinine, mg/dL*
1.0 (0.8–1.2)
1.0 (0.8–1.2)
1.0 (0.8–1.2)
Direct vision
98.9 (195 454)
66.0 (534)
68.1 (96)
0.71 (1)
Previous MI
47.0 (92 835)
63.0 (510)
58.2 (82)
Thoracoscopy
0.13 (252)
0.74 (6)
Previous CABG
1.32 (2603)
0.87 (7)
0.71 (1)
Combination
0.04 (70)
0.12 (1)
0.71 (1)
Previous PCI
25.3 (49 953)
59.0 (477)
50.4 (71)
Robotic assisted
0.66 (1302)
33.0 (267)
30.5 (43)
LVEF, %
53 (45–60)
55 (45–60)
55 (45–60)
IMA artery use
β-Blockers
89.4 (176 727)
90.5 (732)
91.5 (129)
LIMA
94.0 (185 850)
94.4 (764)
94.3 (133)
Lipid-lowering agent
78.4 (154 935)
83.7 (677)
82.3 (116)
RIMA
0.84 (1652)
0.87 (7)
0.71 (1)
Aspirin
82.2 (162 559)
83.8 (678)
87.9 (124)
Both IMAs
ADP inhibitor <5
days
11.3 (22 323)
25.2 (204)
27.0 (38)
No distal targets IMA
1 (1–1)
1 (1–1)
1 (1–1)
2.0 (3890)
10.8 (87)
5.0 (7)
No distal targets vein
grafts
2 (2–3)
0 (0–2)
0 (0–2)
23.7 (46 881)
32.8 (265)
34.8 (49)
No distal targets
arterial grafts
0 (0–0)
0 (0–0)
0 (0–0)
GP IIb/IIIa inhibitor
Presentation of
NSTEMI
5.1 (10 170)
4.7 (38)
4.96 (7)
CABG volume
128 (75–210)
143 (83–232)
120 (79–232)
Three-vessel
disease
79.4 (157 032)
72.1 (583)
66.7 (94)
Any blood products
used
2 (0–2)
2 (1–3)
33.8 (66 790)
27.6 (223)
27.7 (39)
RBC units, 1
million/μL
2 (1–2)
Left main disease
Prox LAD disease
56.9 (112 500)
60.6 (490)
60.3 (85)
Frozen plasma
units, 1 million/μL
0 (0–1)
0 (0–0)
0 (0–1)
Platelet units, 1
million/μL
0 (0–1)
1 (0–2)
0 (0–1)
Continuous variables are presented by median (interquartile range), and
categorical variables are presented by percentage (n). BMI indicates body mass
index; CABG, coronary artery bypass grafting; CAD, coronary artery disease;
HCR, hybrid coronary revascularization; LAD, left anterior descending coronary
artery; LVEF, left ventricular ejection fraction; MI, myocardial infarction; NSTEMI,
non–ST-segment elevation myocardial infarction; PCI, percutaneous coronary
intervention; and PVD, peripheral vascular disease.
*Creatinine measured in nondialysis patients.
consisted of less invasive techniques than median sternotomy in comparison with conventional CABG. Additionally,
cardiopulmonary bypass was less commonly used in the
HCR groups than in CABG (83.4%, 45.0%, and 36.9%
after CABG, staged HCR, and concurrent HCR, respectively). Conversion to the use of cardiopulmonary bypass
was similar among the groups (CABG, 0.6%; staged HCR,
0.8%; and concurrent HCR, 0.0%). When cardiopulmonary
bypass was used, the on-pump times tended to be shorter
after HCR. In all groups the use of the left IMA was primarily used alone (≈94%), but sometimes also in combination
with the right IMA (≈5%). Robotic technology to assist in
IMA harvesting was used in 33.0% and 30.5% of patients
31.4 (62 082)
28.2 (228)
19.9 (28)
Continuous variables were presented by median (interquartile range), and
categorical variables were presented by percentage (n). CABG indicates coronary
artery bypass grafting; CPB, cardiopulmonary bypass; HCR, hybrid coronary
revascularization; IMA, internal mammary artery; LIMA, left internal mammary
artery; OPCAB, off-pump coronary artery bypass grafting; OR, operating room;
RBC, red blood cell; and RIMA, right internal mammary artery.
undergoing staged and concurrent HCR, respectively, versus
only 0.66% in the CABG group. As expected, the total number of vein grafts was higher in the CABG group (median,
2; interquartile range, 2–3) in comparison with both HCR
groups (both medians equal zero; interquartile range, 0–2).
Procedural time, as measured by skin incision time and total
time in the operating room, was shorter after staged HCR
procedures than after concurrent HCR and CABG. The use
of blood products was lower after concurrent HCR in comparison with staged HCR and conventional CABG (31.4%,
28.2%, and 19.9%), as well.
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876 Circulation September 9, 2014
Table 3. Unadjusted and Adjusted Outcomes for Isolated CABG and Staged and Concurrent HCR
Major morbidity or mortality
Operative mortality
Isolated CABG
% (n)
Staged HCR
% (n)
11.8 (23 385)
12.0 (97)
1.5 (2984)
1.4 (11)
P Value
Concurrent HCR
% (n)
0.93 (0.75–1.16)*
0.53*
11.4 (16)
0.94 (0.56–1.56)*
0.80*
0.74 (0.42–1.30)*
0.29*
3.6 (5)
2.26 (0.99–5.17)*
0.053*
OR (95% CI)
OR (95% CI)
P Value
Permanent stroke
1.2 (2446)
0.5 (4)
0.39 (0.15–1.07)
0.069
1.4 (2)
1.16 (0.30–4.49)
0.83
Reoperation
2.2 (4354)
2.4 (19)
1.06 (0.68–1.66)
0.80
3.6 (5)
1.58 (0.66–3.78)
0.30
Renal failure†
1.8 (3365)
1.7 (13)
0.97 (0.59–1.60)
0.91
1.6 (2)
0.96 (0.30–3.05)
0.94
Prolonged ventilation
8.2 (16 181)
7.8 (63)
0.94 (0.71–1.25)
0.68
6.4 (9)
0.79 (0.44–1.42)
0.43
Mediastinitis
0.35 (691)
0.0 (0)
NA‡
NA‡
0.0 (0)
NA‡
Surgical site infection
1.23 (2438)
0.74 (6)
0.60 (0.27–1.34)
0.21
0.71 (1)
0.57 (0.08–4.09)
Sepsis
0.72 (1417)
0.99 (8)
1.38 (0.69–2.79)
0.36
0.0 (0)
NA‡
NA‡
0.58
NA‡
Displayed are the event rates for in-hospital outcomes, and odds ratios (ORs) and 95% confidence intervals (CIs), as well, using the isolated CABG group as a
reference. CABG indicates coronary artery bypass grafting; HCR, hybrid coronary revascularization; and NA, not available.
*For the composite outcome and operative mortality, the ORs and 95% CIs were adjusted for differences in baseline risk; for the remaining, nonfatal outcomes,
unadjusted ORs are presented.
†Among patients without previous renal failure.
‡ORs could not be calculated because there is no event for the outcome of interest in at least 1 of the comparison groups.
In-Hospital Outcomes
The in-hospital outcomes are displayed as event rates and
unadjusted and adjusted odds ratios in Table 3. The composite end point of in-hospital mortality, stroke, reoperation, renal failure, prolonged ventilation, and mediastinitis
was comparable between CABG and staged HCR (adjusted
OR, 0.93; 95% CI, 0.75–1.16; P=0.53) and between CABG
and concurrent HCR (adjusted OR, 0.94; 95% CI, 0.56–
1.56; P=0.80). Statistically, operative mortality was similar
between CABG and staged HCR (adjusted OR, 0.74; 95%
CI, 0.42–1.30; P=0.29), and CABG and concurrent HCR;
although a trend toward higher mortality was observed
among patients who underwent concurrent HCR (adjusted
OR, 2.26; 95% CI, 0.99–5.17; P=0.053). The 5 reported
deaths in the concurrent HCR group were either cardiac
related (n=4) or attributable to pulmonary causes (n=1).
Among the nonfatal end points, a trend toward lower risk
of stroke after staged HCR was found in comparison with
the CABG group. Postoperative length of stay tended to be
shorter after concurrent HCR and CABG (median [interquartile range]=5 [4–7] days versus 6 [4–7] days, P=0.101),
and also after staged HCR and CABG (5 [4–7] days versus 6
[4–7] days, P=0.098).
Discussion
This study represents the first nationwide assessment of
the use, characteristics, and in-hospital outcomes of hybrid
coronary procedures among patients with multivessel coronary artery disease. In contemporary practice, HCR, either
performed as staged or concurrent procedures, remains
uncommon, because it represents only a mere 0.5% of the
total CABG volume. Moreover, even among the hospitals
that performed HCR (approximately one-third of all hospitals with CABG capabilities), the use of HCR was <1% of
the total CABG volume. The low adoption of HCR among
US hospitals can in part be attributed to the low use of minimally invasive surgical techniques, because hospitals that
performed HCR without minimally invasive techniques were
also less likely to perform HCR. Additionally, the low use
of concurrent HCR is likely attributable to the limited availability of hybrid operating rooms. Over a relatively short time
period for which we have data available (<2 years), no temporal trend could be observed for the use of HCR in current
US practice. In comparison with CABG, patients who underwent concurrent HCR or staged HCR had higher-risk profiles, but less extensive coronary disease. As expected, HCR
was more frequently performed by using less invasive surgical approaches, including minimally invasive thoracic access,
use of robotic assistance, and avoidance of cardiopulmonary
bypass. The use of blood products was lower after concurrent HCR than after staged HCR and conventional CABG,
as well, and in-hospital outcomes were overall comparable,
although operative mortality tended to be higher in the concurrent HCR than in staged HCR and CABG.
Clinical Outcomes
In the past 5 years, several studies have been published on
in-hospital clinical outcomes after concurrent and staged
HCR procedures.7,9–17 In Table 4, we have summarized the
key findings from these studies. The number of patients
who underwent HCR in these studies ranged from 5 to 300
patients, and most operators used a partial sternotomy or a
small lateral thoracotomy approach with or without the use
of robotic assistance. Overall, low mortality rates are seen
in studies that used minimally invasive techniques (0%–
1.3%), with equally low rates for stroke (0%–1.0%) and
reoperation for bleeding (0%–4.2%). However, in 1 larger
study by Zhao et al11 (n=112), HCR was performed by using
conventional median sternotomy with open IMA harvesting
and with fewer restrictions for study eligibility. In-hospital
mortality in this cohort was 2.7%, with stroke rates of 1.8%
and reoperation for bleeding of 2.7%. It should be noted
that, in this study, unplanned procedures, in which PCI was
performed because intraoperative findings such as graft
defects, poor conduits, or poor target vessel, made up 40%
of the patient population, which could explain some of the
excess of adverse events in this study. Unlike the findings
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Harskamp et al Hybrid Revascularization in the United States 877
Table 4. Summary of Recent Studies That Published Information on In-hospital Outcomes Following HCR
Author, y
Kon, 2008
Ref.
No. of Patients
Concurrent
Approach
Mortality, %
Stroke, %
Reoperation for
Bleeding, %
Hospital Stay,
days
9
15
Yes
MIDCAB
0
0
0
3.7±1.4
Bonatti, 2008
10
5
Yes
Endo-ACAB
0
0
0
6 (5–7)
Zhao, 2009
11
112
Yes
Median sternotomy
2.7
1.8
2.7
6 (1–97)
Bachinsky, 2012
13
25
Yes
Robotically assisted
0.0
0.0
0.0
5.1±2.8
Adams, 2013
12
96
Yes
Robotically assisted
0.0
1.0
4.2
4 (3–7)
Zhou, 2013
16
141
Yes
Partial sternotomy
0.7
0.7
2.8
8.2±2.5
Delhaye, 2010
17
18
No
Median sternotomy
0.0
0.0
0.0
10 (10–11)
Repossini, 2012
14
166
No
MIDCAB
1.2
0.0
0.0
6.5±1.8
Srivastava, 2013
15
238
Both
Robotically assisted
1.3
0.8
4.2
6 (3–54)
7
300
Both
Robotic / endo-ACAB
1.3
1.0
2.0
5 (2–76)
Halkos, 2013
Endo-ACAB indicates endoscopic atraumatic coronary artery bypass, HCR, hybrid coronary revascularization; and MIDCAB, minimally invasive direct coronary artery
bypass.
from these highly experienced HCR institutions, our analysis presented outcome data from all CABG centers that
participate in the STS registry of which the vast majority
only perform HCR occasionally. Despite the higher use of
conventional techniques (≈40% of HCR procedures were
performed with median sternotomy and cardiopulmonary
bypass) and differences in patient populations, the overall
event rates of staged HCR in our study appear to be comparable to those reported previously. However, the reported
rates for in-hospital mortality and the need for reoperation
after concurrent HCR seem to be higher than in previous
studies. Although speculative, this may suggest that these
procedures are more often used in patient populations that
are at higher risk for complications, as reflected by the
higher preoperative incidence of stroke, peripheral vascular
disease, and renal failure.
Bleeding Outcomes and the Use of Anticoagulants
There are concerns that HCR, particularly when performed
concurrently, carries an increased bleeding risk because of
the necessity for 2 distinct anticoagulation protocols for
the surgical and percutaneous aspects of the procedure.
However, as shown in our study, the use of blood products
was markedly lower in concurrent HCR group, and the need
for reoperation including bleeding were comparable between
concurrent HCR and CABG and staged HCR and CABG, as
well, despite the higher rates of recent ADP inhibitor use,
and glycoprotein IIb/IIIa inhibitors among HCR patients.
New antiplatelet agents, such as the direct thrombin inhibitor bivalirudin, have been proposed as an anticoagulant in
HCR cases to facilitate the use of a single anticoagulation
protocol, which may alleviate concerns about bleeding
complications.18
Hospital Stay
Given the use of more minimally invasive techniques, it
was anticipated that postoperative hospital length of stay
would be shorter in patients who underwent concurrent
HCR versus CABG. In other studies, the average hospital
stay for concurrent HCR ranged from ≈4 to 8 days (see
Table 4). Among studies that compared intensive care and
postoperative hospital length of stay between 1-stage HCR
and conventional CABG, both time of recovery at the intensive care unit and time to discharge were shorter in the HCR
group.3,9,13 In our study, postprocedural length of hospital
stay tended to be shorter after HCR than after CABG, but
did not reach statistical significance. A number of reasons
may be attributable to this finding: (1) the use of minimally
invasive techniques was lower in our cohort than in others;
(2) HCR occurred in a more heterogenous (and generally
sicker) patient population; (3) HCR procedures performed
do not only represent those performed by high-volume
operators in specialized HCR centers but instead present an
overall experience among US hospitals.
Decision-Making Process: HCR Versus CABG
In our study, data were not collected on why surgeons and
cardiologists opted for HCR instead of conventional CABG
or multivessel PCI. Other studies, also seldom provided data
on why HCR was performed instead of CABG. In an attempt
to assess this, Zhao et al11 retrospectively showed that, in the
majority of cases, HCR was preferred over CABG to either
minimize surgical risk (47.8%) or because of ungraftable vessels (43.3%). Given the differences in clinical and procedural
characteristics in our study, we speculate that similar reasons
may have been involved in the decision making for performing HCR in our study population. Additionally, our study
showed that centers that have experience with less invasive
CABG techniques are also more likely to adopt HCR as a
revascularization strategy for patients with multivessel coronary disease.
Defining Hybrid Procedures
Ever since the first publication on the combined use of surgical and
percutaneous techniques for coronary revascularization in the late
1990s, there has been debate on what should be defined as HCR
and what should not.1 For this analysis, we used the STS version
2.73 definition of HCR, from which we then included planned
HCR cases involving IMA use and coronary stenting during 1
hospitalization, in a broad population and without restriction on
surgical techniques used. In previous single-center registries that
reported outcomes on HCR, more stringent definitions have been
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878 Circulation September 9, 2014
used, which may explain some of the difference between these
observations and our own. A more standardized definition for
HCR, as recently proposed, may therefore be helpful to compare
outcomes between various studies.19
Limitations
There are a number of limitations of the current study. First, the
current analysis involves registry data that, owing to their nonrandomized nature, are by definition biased. Second, although
we adjusted properly for known/measured confounding, unmeasured confounding is still present. Third, although this study represents the largest cohort of HCR patients to date, the sample size
and the number of events, as well, are small, and the inferences
on in-hospital outcomes should therefore be done with caution.
Fourth, although the STS database collects information on hybrid
procedures, it only captures information on patients who survived
at least the first stage of a hybrid procedure. As such, information on intention to treat was not available. Although this poses
a limitation for concurrent HCR cases, it poses an even greater
challenge for patients who underwent staged HCR because of
concerns of survival bias. Fifth, because of the inherent limitation
of the STS data collection form, which only collects information on procedures performed during 1 hospitalization, staged
HCR procedures in which the 2 stages are not performed within
the same hospitalization or center, were not captured. As such,
the number of staged HCR procedures is underreported in the
STS database. Sixth, for the current analysis only planned HCR
cases were considered, and unplanned HCR cases were excluded.
Although the STS states clear definitions for what is considered
planned and unplanned, data managers might have misclassified
patients. Seventh, because of the limitations of the STS data collection form, we could not assess detailed information on percutaneous coronary intervention, including the location and length
of the treated lesion, stent (type) use, and residual stenosis. Hence
we could not quantify which vessels were revascularized by
using percutaneous means and which by surgical means. Finally,
information on long-term clinical outcomes (including cardiac
death, nonfatal myocardial infarction, and need for repeat revascularization) could not be assessed, which is of major importance
when assessing the efficacy of HCR as an alternative approach to
surgical coronary revascularization.
Conclusions
HCR is occasionally performed in approximately one-third of
all STS participating hospitals, and represents a fraction of the
total CABG volume in the United States. Patients who undergo
HCR are sicker, but they have less extensive coronary disease.
In comparison with isolated CABG, both concurrent and staged
HCR more frequently involved the use of minimally invasive
surgical techniques and less use of cardiopulmonary bypass.
Adjusted in-hospital clinical outcomes were overall comparable. Randomized clinical trials are warranted to assess the safety
and efficacy of HCR in comparison with CABG or multivessel
PCI among patients who are deemed appropriate candidates.
Sources of Funding
Funding for the statistical analysis on this article was provided by the
Society of Thoracic Surgeons.
Disclosures
Dr Thourani serves on the advisory boards of Edwards Lifesciences,
St. Jude Medical, Sorin group, Maquet, Direct Flow Medical Inc.,
and receives research grants from Edwards Lifesciences and Soring
group. Dr Halkos serves as a consultant for Intuitive Surgical Inc. and
Medtronic Inc. Dr Peterson is a consultant for Boehringer Ingelheim,
Genentech, Janssen Pharmaceutical Products, Merck, SanofiAventis, and receives research grants from Eli Lilly, and Janssen
Pharmaceutical Products. The other authors report no conflicts.
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Clinical Perspective
Coronary artery bypass grafting (CABG) provides superior longitudinal outcomes in comparison with percutaneous coronary intervention in selected patients with multivessel coronary artery disease. The survival advantage of CABG is primarily
attributable to the left internal mammary artery–to–left anterior descending graft. In the current era of drug-eluting stents,
the utility of vein grafts over percutaneous coronary intervention in non–left anterior descending target vessels has been
questioned. Hybrid coronary revascularization (HCR) may present an appealing alternative revascularization strategy for
these patients, because it combines the longevity of the left internal mammary artery–to–left anterior descending graft
with drug-eluting stent implantation in non–left anterior descending lesions. Although the most recent American College
of Cardiology/American Heart Association guidelines on coronary revascularization endorse HCR with a class IIa recommendation, evidence is limited. Therefore, we sought to describe the practice patterns and in-hospital outcomes in the use of
HCR by analyzing data from the Society of Thoracic Surgeons Adult Cardiac Database. We found that HCR is performed
in approximately one-third of US hospitals, where it represents a small fraction of total CABG volume, and it tends to be
performed more often in patients with higher cardiovascular risk profiles. The majority of HCR procedures were performed
as staged procedures. Overall, in-hospital clinical outcomes did not significantly differ between CABG and HCR, which
suggests that HCR may present an equally safe alternative for CABG surgery in a carefully selected patient population.
However, owing to the limitations of this analysis, future study is needed, and randomized clinical trials are warranted to
assess the safety and long-term efficacy of HCR in comparison with CABG or multivessel percutaneous coronary intervention in patients with multivessel coronary artery disease.
Go to http://cme.ahajournals.org to take the CME quiz for this article.
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Practice Patterns and Clinical Outcomes After Hybrid Coronary Revascularization in the
United States: An Analysis From the Society of Thoracic Surgeons Adult Cardiac
Database
Ralf E. Harskamp, J. Matthew Brennan, Ying Xian, Michael E. Halkos, John D. Puskas, Vinod
H. Thourani, James S. Gammie, Bradley S. Taylor, Robbert J. de Winter, Sunghee Kim, Sean
O'Brien, Eric D. Peterson and Jeffrey G. Gaca
Circulation. 2014;130:872-879; originally published online July 23, 2014;
doi: 10.1161/CIRCULATIONAHA.114.009479
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