Robotics in caRdiac suRgeRy

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Nov 2, 2013 (3 years and 11 months ago)

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Scandinavian Journal of Surgery 98: 120–124, 2009
Robotics in caRdiac suRgeRy
e. Rodriguez,

W. R. chitwood
East Carolina Heart Institute, Department of Cardiovascular Sciences East Carolina University,

Greenville (NC), U.S.A.
abstRact
Minimally invasive surgery has revolutionized the surgical field over the last two de
-
cades. Robotic assisted surgery is the latest iteration towards less invasive techniques.
cardiac surgeons have slowly adapted minimally invasive and robotics techniques into
their armamentarium. in particular, minimally invasive mitral valve surgery has evolved
over the last decade and become the preferred method of mitral valve repair and replace
-
ment at certain specialized centres worldwide because of excellent results. We have de
-
veloped a robotic mitral valve surgery program which utilizes the da Vinci
®
telemanipu
-
lation system allowing the surgeon to perform complex mitral valve repairs through 5mm
port sites rather than a traditional median sternotomy. in this rapidly evolving field, we
review the evolution and clinical results of robotically-assisted mitral valve surgery and
take a look at the other cardiac surgical procedures for which da Vinci
®
is currently being
used.
Key words: Surgical procedures; minimally invasive; thoracic surgery; video-assisted; robotics;
telemedicine/instrumentation; mitral valve insufficiency; TECAB
Correspondence:
Evelio Rodriguez, M.D.
East Carolina Heart Institute Room No. 3213
600 Moye Boulevard
Greenville , North Carolina, 27834, U.S.A.
Email:
rodriqueze@ecu.ed
u
have moved serially from using direct vision smaller
incisions for mitral operations (Level I) to assistant-
held video-assistance (Level II), to video-directed
voice-activated robotic techniques (Level III) to ro
-
botic mitral valve surgery using the da Vinci
®
system
(Intuitive Surgical Inc., Mountain View, CA) (Level
IV). Standard endoscopic instrumentation was used
for levels I to III but with only 4 degrees of freedom,
dexterity was limited. Additionally, when working
through a fixed entry point the surgeon had to re
-
verse hand movements (fulcrum effect) and higher
operator handle strain due to instrument-shaft shear
forces led to muscle fatigue. This resulted in deterio
-
rating motor skills and disconnection between opti
-
mal visual-motor synchrony, commonly associated
with endoscopic surgery. Computer-assisted robotic
telemanipulation systems have provided a solution
to these constraints.
We have used the da Vinci
®
system which is com
-
posed of three components: a surgeon console, an
instrument cart and a visioning platform and is the
most widely used system in cardiac surgery today.
The operative console allows the surgeon to immerse
himself in a 3-dimensional high-definition video
-
INTRoDUCTIoN
During the past decade, improvements in endoscopic
technology and techniques have resulted in a sub
-
stantial increase in the number of minimally invasive
(MI) surgical procedures being performed in special
-
ties such as general surgery and urology. Cardiac sur
-
geons were initially reluctant to adopt these new
techniques as they limited access to and exposure of
the heart during complex and difficult cardiovascular
procedures but, in the mid-1990s, they began to re-
cognize the significant advantages of minimizing sur
-
gical trauma by reducing incision size.
Minimally invasive cardiac surgery has evolved
through graded levels of difficulty each with progres
-
sively less exposure and an increasing reliance on
video assistance. At East Carolina University, we
121
Robotics in cardiac surgery
scopic image. Finger and wrist movements are regis
-
tered through sensors and then translated into scaled
tremor-free movements with 7 degrees of freedom.
Wrist-like articulations at the end of microinstru
-
ments bring the pivoting action of the instrument to
the plane of the operative field improving dexterity
in tight spaces and allowing ambidextrous suture
placement. With the availability of these telesurgery
systems, totally endoscopic robotic cardiac valve op
-
erations have now become possible.
In this article we review the development and cur
-
rent state of robotic cardiac surgery.
MITRAL VALVE RECoNSTRUCTIoN
The first robotic mitral valve repair was performed in
May 1998 by Carpentier using an early prototype of
the da Vinci
®
articulated intracardiac “wrist” robotic
device (1). A week later, Mohr performed the first
coronary anastomosis and repaired 5 mitral valves
with the device (2). Grossi et al. of New York Univer
-
sity partially repaired a mitral valve using the Zeus


system (Computer Motion Inc.) but no annuloplasty
ring was inserted. Four days later, in May 2000, our
group performed the first complete da Vinci
®
mitral
repair in North America. Subsequently we performed
20 other mitral repairs as part of a Phase 1 Food and
Drug Administration (FDA) trial designed to deter
-
mine the safety and efficacy of da Vinci
®
(3). These
initial results were encouraging and prompted a
phase II multicenter FDA trial which was completed
in 2002 (4). A total of 112 patients were enrolled at 10
different institutions and all types of repairs were
performed. At 1 month after surgery, 92% had either
no or grade 1 MR, 8% had grade 2 or higher and 5%
subsequently required reoperation. Although the re
-
operative number was high for the number of pa
-
tients, failures were distributed evenly among centers
with some centers having performed fewer than 10
procedures. There were no deaths, strokes or device-
related complications. These results prompted FDA
approval of the da Vinci
®
system for MV surgery in
November 2002.
other early robotic assisted mitral valve surgery re
-
ports included:
1) Tatooles et al. reported their experience with 25
patients and demonstrated excellent results with
no mortality, device-related complications, strokes
or reoperations for bleeding. one patient had a
transient ischemic attack 7 days after surgery. The
CPB and XC times were 126.6 ± 25.7 minutes and
87.7 ± 20.9 minutes, respectively. Eighty-four per
-
cent were extubated in the operating room, 8 were
discharged home within 24 hours and the mean
hospital stay was 2.7 days (5). However, there was
a 28% rate of readmission using this aggressive
discharge policy and two patients required inter
-
val mitral valve replacement.
2) Jones et al. reported their series of 32 patients at a
community hospital (6). They performed concom
-
itant procedures in five patients (tricuspid valve
repair n = 3 and MAZE procedure n = 2). There
were two deaths in this series where neither was
reported as a device-related complication. Compli
-
cations included reoperations for repair failure
(n = 3), stroke (n = 1), groin lymphocoele (n = 1) and
pulmonary embolism (n = 1).
3) In a nonrandomized single surgeon experience
from the University of Pennsylvania, Woo et al.
demonstrated that robotic surgery patients had a
significant reduction in blood transfusion and
length of stay compared to sternotomy patients
(7).
4) Folliguet et al. compared patients undergoing ro
-
botically-assisted mitral valve repair to a matched
cohort undergoing sternotomy (n = 25 each) (8).
The robotic group had a shorter hospital stay
(7 days vs 9 days, p = 0.05) but besides this there
were no differences between the two groups.
More recent and larger series include:
1) Murphy et al. reported their experience in 127 pa
-
tients undergoing robotic MV surgery of which 5
were converted to median sternotomy and 1 to
thoracotomy; seven patients had valve replace
-
ment and 114 had repair (9). There was 1 in-hospi
-
tal death, 1 late death, 2 strokes and 22 patients
developed new onset of atrial fibrillation. Blood
product transfusion was required in 31% of pa
-
tients and two (1.7%) patients required reopera
-
tion. Post-discharge echocardiograms were avail
-
able in 98 patients at a mean follow-up of 8.4
months with no more than 1+ residual MR in
96.2%.
2) our own institution’s experience included 300 pa
-
tients undergoing robotic mitral valve repair be
-
tween May 2000 and November 2006 having
echocardiographic and survival follow-up in 93%
and 100% of patients, respectively (10). There were
2 (0.7%) 30-day mortalities and 6 (2.0%) late mor
-
talities. No sternotomy conversions or mitral valve
replacements were required. Immediate post re
-
pair echocardiograms showed the following de
-
grees of mitral regurgitation: none/trivial, 294
(98%); mild, 3 (1.0%); moderate, 3 (1.0%); and se
-
vere, 0 (0.0%). Complications included 2 (0.7%)
strokes, 2 transient ischemic attacks, 3 (1.0%) myo
-
cardial infarctions, and 7 (2.3%) reoperations for
bleeding. The mean hospital stay was 5.2 +/– 4.2
(standard deviation) days. Sixteen (5.3%) patients
required a reoperation. Echocardiographic fol
-
low-up demonstrated the following degrees of
mitral regurgitation: none/trivial, 192 (68.8%);
mild, 66 (23.6%); moderate, 15 (5.4%); and severe,
6 (2.2%).
Taken altogether, these series validate the results of
previous reports demonstrating that robotic mitral
valve surgery is safe and has excellent early-term and
mid-term results. The introduction of newer robotic
instrumentation like the dynamic left atrial retractor
and simpler mitral valve repair techniques such as
the “Haircut Posterior Leaflet-Plasty”(11) and the
“American Correction”(12) will facilitate the use of
robotic mitral valve techniques by a larger number of
cardiac surgeons.
122
E. Rodriguez
,
W. R. Chitwood
CoRoNARY REVASCULARIZATIoN
The range of robot-assisted coronary operations
ranges from internal mammary artery (IMA) harvest
with a hand-sewn anastomosis, performed either on
or off-pump through a minithoracotomy or median
sternotomy, to totally endoscopic coronary artery by
-
pass grafting (TECAB). Early reports demonstrated
the feasibility and safety of harvesting the IMA with
the da Vinci
®
system with harvest times < 30 minutes
achievable once the learning curve had been negoti
-
ated (13–15).
In 1998 Loulmet et al. demonstrated the feasibility
of TECAB on an arrested heart by using da Vinci
®
to
harvest the left IMA (LIMA) and to perform a LIMA
to left anterior descending (LAD) coronary anastomo
-
sis in two patients (16). In 2000, Falk et al. reported
TECAB on 22 patients of which 4 were converted to
minithoracotomy for anastomotic bleeding or graft
issues (17). In the remaining 18 patients, grafts were
widely patent at 3 months with no major complica
-
tions. The same group subsequently reported the first
off-pump TECAB using an endoscopic stabilizing

device (18). Dogan et al. reported 45 arrested heart
TECAB procedures in 2002, of which 8 patients un
-
derwent double vessel revascularization with both
IMAs (19). The initial conversion rate of 22% dropped
to 5% in the last 20 patients. The procedural time for
single-vessel TECAB was 4.2 +/– 0.4 hours, CPB time
was 136 +/–11 minutes and XC time was 61 +/–
5 minutes.
Subramanian et al. achieved multivessel revascu
-
larization (mean number of grafts, 2.6) in 30 patients
using robotically-harvested IMAs (20). Depending on
the specific target, either a minithoracotomy or trans
-
abdominal approach was employed. Twenty-nine
(97%) patients were extubated on the operating table,
77% were discharged within 48 hours and only 2 pa
-
tients needed readmission. In addition, only 1 patient
needed conversion to sternotomy and there was no
mortality. However, the largest single institution se
-
ries comes from Srivastava et al. with 150 patients
undergoing robotic-assisted bilateral IMA harvesting
and off-pump CABG via minithoracotomy (21). Two
patients presented with chest pain after discharge
secondary to graft occlusion; in both cases, treatment
using percutaneous intervention was successful. In
55 patients undergoing computed tomography an
-
giography at 3 months, all 136 grafts were patent.
A multicentre Investigational Device Exemption
trial was reported by Argenziano et al. in 2006 (22).
Ninety-eight patients requiring single-vessel LAD
revascularization were enrolled at 12 centers; thirteen
patients (13%) were excluded intraoperatively (e.g.
failed femoral cannulation, inadequate working
space). In the remaining 85 patients who underwent
TECAB, CPB time was 117 +/– 44 minutes, XC time
was 71 +/– 26 minutes and hospital length of stay
was 5.1 +/– 3.4 days. There were five (6%) conver
-
sions to open techniques. There were no deaths or
strokes, one early reintervention and one myocardial
infarction. Three-month angiography was performed
in 76 patients, revealing significant anastomotic
stenoses (> 50%) or occlusions in 6 patients. overall
freedom from reintervention or angiographic failure
was 91% at 3 months. United States FDA approval of
use of da Vinci

for coronary revascularization was
largely based on this study.
Reports of robotically-assisted coronary surgery
have mostly involved highly-selected patient popula
-
tions which require limited revascularization, usually
of the anterior wall (23). In these circumstances, sur
-
geons have been able to achieve totally endoscopic
LIMA-LAD grafting with high success rates after the
initial learning curve. Combining robotic TECAB of
the LAD with PCI of a second coronary target, so-
called hybrid revascularization, effectively combines
a MI approach with the proven long-term benefits of
LIMA-LAD grafting and is likely to increase particu
-
larly with advances in robotic instrumentation. Re
-
cent work by Katz et al. has demonstrated that this
approach can be accomplished with no mortality, low
perioperative morbidity and excellent 3-month angio
-
graphic LIMA patency (96.3%) (24). More recently,
these results have been corroborated by Gao et al. in
their series of 42 patients undergoing hybrid revas
-
cularization (25). Irrespective of the method, long-
term follow-up of these grafts is needed to determine
if they have the same excellent patency (> 90% at 10
years) as those performed through a median sterno
-
tomy.
ATRIAL FIBRILLATIoN SURGERY
There have been a few case reports of patients under
-
going combined robotic mitral valve and atrial fibril
-
lation (MV/AF) surgery demonstrating that these
procedures are safe (26–29). one small (n = 16) series
of patients undergoing robotic MV/AF surgery using
the Flex-10 microwave catheter (Guidant, Indianapo
-
lis, IN) from our own institution has been reported
(30). The ablative procedure added 42 ± 16 minutes to
the MV repair and 1.3 days to hospitalization. At 6
months follow-up, 73% were in sinus rhythm, 20%
were paced and 7% were in atrial fibrillation.
Roberts et al. recently reported their robotic endo
-
scopic Cox-Cryomaze technique. Using a warm beat
-
ing heart strategy they are able to perform a full set
of left atrial argon-based cryolesions and closure of
the left atrial appendage (31).
LEFT VENTRICULAR LEAD PLACEMENT
Numerous prospective studies have demonstrated
that cardiac resynchronization therapy with or with
-
out implantable cardioverter-defibrillator capability
improves ventricular function, exercise capacity and
quality of life, as well as reduce mortality and heart
failure hospitalizations in patients with symptomatic
heart failure and delayed intraventricular conduction
despite optimal medical therapy (32). Left ventricular
lead placement is usually accomplished percutane
-
ously through coronary sinus cannulation, advancing
the lead into a major cardiac vein. This technique is
associated with long fluoroscopy times and is not
applicable to all patients because of anatomical limi
-
123
Robotics in cardiac surgery
tations in coronary venous anatomy. Early and late
failures occur in approximately 12% and 10% of pro
-
cedures, respectively (33). Surgical epicardial lead
placement is often a rescue therapy for these pa
-
tients.
Early reports by DeRose et al. demonstrated the
efficacy of robot-assisted LV lead implantation (34).
They reported results for 13 patients, 6 of whom had
previous CABG, with no complications or technical
failures. Navia’s series of minithoracotomy or ro
-
botic/endoscopic LV lead placement included 41 pa
-
tients without mortality, intraoperative complications
or implantation failures (35). A minimally invasive
surgical approach is very attractive as it allows sur
-
geons to determine the best epicardial site for im
-
plantation by mapped stimulation and may therefore
entail greater success rates than transvenous implan
-
tation. A randomized study comparing both tech
-
niques is in progress.
INTRACARDIAC TUMoR RESECTIoN
Cardiac tumors, although relatively uncommon and
mostly benign, almost always should be resected to
prevent thromboembolic complications. Murphy et
al. recently reported endoscopic excision of 3 left
atrial myxomas using either a left atriotomy or right
atriotomy with trans-septal approach. Autologous
pericardial patches were used to repair septal defects
following excision (36). The mean CPB and XC times
were 103 ± 40 minutes and 64 ± 2 minutes, respec
-
tively. Impressive results were reported with all pa
-
tients being discharged on day 4 and resuming nor
-
mal activity 3 weeks after surgery. Similarly, Woo et
al. used robotic techniques to excise an aortic valve
papillary fibroelastoma with the patient being dis
-
charged on the 3
rd
postoperative day and back to
work within one month (37).
CoNGENITAL SURGERY
A few congenital cardiac conditions in both children
and adults lend themselves to a minimally invasive
approach. Del Nido’s group from the Boston Chil
-
dren’s Hospital published their 2-year experience
with 15 patients undergoing patent ductus arteriosus
(PDA) closure (n = 9) or vascular ring repair (n = 6)
utilizing the da Vinci
®
system (38). The patients were
aged 3–18 years and only one was converted to a
thoracotomy because of pleural adhesions. The total
operative times were a little prolonged at 170 ± 46
minutes (PDA) and 167 ± 48 minutes (vascular ring).
Nevertheless, all were extubated in the operating
room and were discharged after a median of 1.5 days.
Bonaros et al. showed that the learning curve is steep
and associated with a rapid decrease in operative
times (39).
In a US FDA Investigational Device Exemption
trial, Argenziano et al. demonstrated that atrial septal
defects (ASDs) in adults can be closed safely and ef
-
fectively using totally endoscopic robotic approaches
with a median XC time of 32 minutes (40). one of 17
patients had a residual shunt across the atrial septum
which was repaired via minithoracotomy on post-
operative day 5. The reoperative finding was that the
atrial septal primary suture line was intact but there
was a tear medial to it. This failure was therefore
likely related to use of a direct closure technique
rather than using a patch repair and therefore not a
failure of the robotic technique per se. Morgan et al.
subsequently demonstrated that robotic ASD closure
hastens postoperative recovery and improves quality
of life compared to either a mini-thoracotomy or me
-
dian sternotomy approach (41).
CoNCLUSIoN
Although robotic cardiac surgery is in a state of evo
-
lution, the early results are encouraging with evi
-
dence demonstrating fewer blood transfusions,
shorter hospital stay, faster return to preoperative
function levels and improved quality of life compared
to those having a sternotomy. This translates into im
-
proved utilization of limited healthcare resources. It
is clear that the continued evolution of totally endo
-
scopic cardiac surgery depends on the development
of new adjunctive technology, such as retraction sys
-
tems, perfusion catheters and sutureless anastomotic
devices. Thus, although the surgical robot allows un
-
precedented closed chest surgical access to the heart,
it is only one of many new tools that are prerequisite
for successful minimally invasive cardiac surgery. It
will require a combined effort of physicians with our
industry partners to fill in these technological gaps
that are present in our current armamentarium of
minimally invasive tools. Surgical scientists must
continue to critically evaluate this technology and
despite enthusiasm, caution cannot be overempha
-
sized. Traditional cardiac operations still enjoy proven
long-term success and ever-decreasing morbidity and
mortality and remain our measure for comparison. To
determine if robotic techniques could become the
new standard in cardiac surgery, long-term results
are needed.
REFERENCES
0
1. Carpentier A, Loulmet D, Aupecle B, et al: Computer assisted
open heart surgery. First case operated on with success. C R
Acad Sci III 1998;321(5):437–442
0
2. Mohr FW, Falk V, Diegeler A, Autschback R: Computer-en
-
hanced coronary artery bypass surgery. J Thorac Cardiovasc
Surg 1999;117(6):1212–1214
0
3. Nifong LW, Chu VF, Bailey BM, et al: Robotic mitral valve re
-
pair: experience with the da Vinci system. Ann Thorac Surg
2003; 75(2):438–442; discussion 443
0
4. Nifong LW, Chitwood WR, Pappas PS, et al: Robotic mitral
valve surgery: a United States multicenter trial. J Thorac Car
-
diovasc Surg 2005;129(6):1395–1404
0
5. Tatooles AJ, Pappas PS, Gordon PJ, Slaughter MS: Minimally
invasive mitral valve repair using the da Vinci robotic system.
Ann Thorac Surg 2004;77(6):1978–1982; discussion 1982–1984
0
6. Jones BA, Krueger S, Howell D, et al: Robotic mitral valve re
-
pair: a community hospital experience. Tex Heart Inst J 2005;
32(2):143–146
0
7. Woo YJ, Nacke EA: Robotic minimally invasive mitral valve
reconstruction yields less blood product transfusion and

shorter length of stay. Surgery 2006;140(2):263–267
124
E. Rodriguez
,
W. R. Chitwood
0
8. Folliguet T, Vanhuyse F, Constantino X, et al: Mitral valve re
-
pair robotic versus sternotomy. Eur J Cardiothorac Surg 2006;
29(3):362–366
0
9. Murphy DA, Miller JS, Langford DA, Snyder AB: Endoscopic
robotic mitral valve surgery. J Thorac Cardiovasc Surg 2006;
132(4):776–781
10. Chitwood WR, Jr., Rodriguez E, Chu MW, et al: Robotic mitral
valve repairs in 300 patients: a single-center experience. J Tho
-
rac Cardiovasc Surg 2008;136(2):436–441
11. Chu MW, Gersch KA, Rodriguez E, et al: Robotic “haircut”
mitral valve repair: posterior leaflet-plasty. Ann Thorac Surg
2008;85(4):1460–1462
12. Lawrie GM: Mitral valve: toward complete repairability. Surg
Technol Int 2006;15:189–197
13. Falk V, Jacobs S, Gummert J, Walther T: Robotic coronary ar
-
tery bypass grafting (CABG) – the Leipzig experience. Surg
Clin North Am 2003;83(6):1381–1386, ix
14. Vassiliades TA, Jr: Technical aids to performing thoracoscopic
robotically-assisted internal mammary artery harvesting.
Heart Surg Forum 2002;5(2):119–124
15. Kappert U, Cichon R, Gulielmos V, et al: Robotic-enhanced
Dresden technique for minimally invasive bilateral internal
mammary artery grafting. Heart Surg Forum 2000;3(4):319–
321
16. Loulmet D, Carpentier A, d’Attellis N, et al: Endoscopic coro
-
nary artery bypass grafting with the aid of robotic assisted
instruments. J Thorac Cardiovasc Surg 1999;118(1):4–10
17. Falk V, Diegeler A, Walther T, et al. Total endoscopic computer
enhanced coronary artery bypass grafting. Eur J Cardiothorac
Surg 2000;17(1):38–45
18. Falk V, Diegeler A, Walther T, et al: Total endoscopic off-pump
coronary artery bypass grafting. Heart Surg Forum 2000;3(1):
29–31
19. Dogan S, Aybek T, Andressen E, et al: Totally endoscopic coro
-
nary artery bypass grafting on cardiopulmonary bypass with
robotically enhanced telemanipulation: report of forty-five
cases. J Thorac Cardiovasc Surg 2002;123(6):1125–1131
20. Subramanian VA, Patel NU, Patel NC, Loulmet DF: Robotic
assisted multivessel minimally invasive direct coronary artery
bypass with port-access stabilization and cardiac positioning:
paving the way for outpatient coronary surgery? Ann Thorac
Surg 2005;79(5):1590–1596; discussion 1590–1596
21. Srivastava S, Gadasalli S, Agusala M, et al: Use of bilateral
internal thoracic arteries in CABG through lateral thoracotomy
with robotic assistance in 150 patients. Ann Thorac Surg 2006;
81(3):800–806; discussion 806
22. Argenziano M, Katz M, Bonatti J, et al: Results of the prospec
-
tive multicenter trial of robotically assisted totally endoscopic
coronary artery bypass grafting. Ann Thorac Surg 2006;81(5):
1666–1674; discussion 1674–1675
23. Anderson CA, Rodriguez E, Chitwood WR, Jr: Robotically
assisted coronary surgery: what is the future? Curr opin Car
-
diol 2007;22(6):541–544
24. Katz MR, Van Praet F, de Canniere D, et al: Integrated coronary
revascularization: percutaneous coronary intervention plus
robotic totally endoscopic coronary artery bypass. Circulation
2006;114(1 Suppl):1473–1476
25. Gao C, Yang M, Wu Y, et al: Hybrid coronary revascularization
by endoscopic robotic coronary artery bypass grafting on beat
-
ing heart and stent placement. Ann Thorac Surg 2009;87(3):
737–741
26. Bolotin G, Kypson AP, Nifong LW, Chitwood WR, Jr: Roboti
-
cally-assisted left atrial fibrillation ablation and mitral valve
repair through a right mini-thoracotomy. Ann Thorac Surg
2004;78(4):e63–64
27. Loulmet DF, Patel NC, Patel NU, et al: First robotic endo
-
scopic epicardial isolation of the pulmonary veins with micro
-
wave energy in a patient in chronic atrial fibrillation. Ann
Thorac Surg 2004;78(2):e24–25
28. Akpinar B, Guden M, Sagbas E, et al: Robotic-enhanced to
-
tally endoscopic mitral valve repair and ablative therapy. Ann
Thorac Surg 2006;81(3):1095–1098
29. Pruitt JC, Lazzara RR, Dworkin GH, et al: Totally endoscopic
ablation of lone atrial fibrillation: initial clinical experience.
Ann Thorac Surg 2006; 81(4):1325–1330; discussion 1330–1133
30. Reade CC, Johnson Jo, Bolotin G, et al. Combining robotic
mitral valve repair and microwave atrial fibrillation ablation:
techniques and initial results. Ann Thorac Surg 2005; 79(2):480–
484
31. Cheema FH, Weisberg JS, Khalid I, Roberts HG, Jr: Warm beat
-
ing heart, robotic endoscopic Cox-cryomaze: an approach for
treating atrial fibrillation. Ann Thorac Surg 2009;87(3):966–
968
32. McAlister FA, Ezekowitz J, Hooton N, et al: Cardiac resynchro
-
nization therapy for patients with left ventricular systolic dys
-
function: a systematic review. Jama 2007;297(22):2502–2514
33. Alonso C, Leclercq C, d’Allonnes FR, et al: Six year experience
of transvenous left ventricular lead implantation for perma
-
nent biventricular pacing in patients with advanced heart fail
-
ure: technical aspects. Heart 2001;86(4):405–410
34. Derose JJ, Jr., Belsley S, Swistel DG, et al: Robotically assisted
left ventricular epicardial lead implantation for biventricular
pacing: the posterior approach. Ann Thorac Surg 2004;77(4):
1472–1474
35. Navia JL, Atik FA, Grimm RA, et al: Minimally invasive left
ventricular epicardial lead placement: surgical techniques for
heart failure resynchronization therapy. Ann Thorac Surg 2005;
79(5):1536–1544; discussion 1536–1544
36. Murphy DA, Miller JS, Langford DA: Robot-assisted endo
-
scopic excision of left atrial myxomas. J Thorac Cardiovasc
Surg 2005;130(2):596–597
37. Woo YJ, Grand TJ, Weiss SJ: Robotic resection of an aortic valve
papillary fibroelastoma. Ann Thorac Surg 2005;80(3):1100–
1102
38. Suematsu Y, Mora BN, Mihaljevic T, del Nido PJ: Totally endo
-
scopic robotic-assisted repair of patent ductus arteriosus and
vascular ring in children. Ann Thorac Surg 2005;80(6):2309–
2313
39. Bonaros N, Schachner T, oehlinger A, et al: Robotically as
-
sisted totally endoscopic atrial septal defect repair: insights
from operative times, learning curves, and clinical outcome.
Ann Thorac Surg 2006;82(2):687–293
40. Argenziano M, oz MC, Kohmoto T, et al: Totally endoscopic
atrial septal defect repair with robotic assistance. Circulation
2003;108 Suppl 1:II191–194
41. Morgan JA, Peacock JC, Kohmoto T, et al: Robotic techniques
improve quality of life in patients undergoing atrial septal
defect repair. Ann Thorac Surg 2004;77(4):1328–1333
Received: April 4, 2009