Hybrid Coronary Revascularization
Abstract
Hybrid coronary revascularization (HCR) is defined as the combination of
coronary artery bypass grafting (CABG) and percutaneous coronary intervention
(PCI) to treat multivessel coronary artery disease. HCR most commonly combines
a minimally invasive CABG procedure involving a left internal thoracic artery
(LITA) to the left anterior descending coronary artery (LAD) anastomosis with
PCI to non-LAD vessels. This technique offers and combines the advantages of
both surgical and percutaneous revascularlization, eliminating at the same time
the disadvantages.
Definition and Rationale
· Hybrid coronary revascularization (HCR) is
defined as the combination of coronary artery bypass grafting (CABG) and
percutaneous coronary intervention (PCI) to treat multivessel coronary artery
disease (CAD). HCR most commonly combines a minimally invasive CABG procedure
involving a left internal thoracic artery (LITA) to the left anterior
descending coronary artery (LAD) anastomosis with PCI to non-LAD vessels. This
technique offers and combines the advantages of surgical and percutaneous
revascularization, eliminating at the same time the disadvantages of both
procedures. In fact, this evolving revascularization technique uses the
survival benefits conferred by the LITA to LAD graft while providing the
patient with complete and minimally invasive coronary artery revascularization
with PCI to the non-LAD vessels. The sequence and timing of the surgical and
interventional components of hybrid therapy can be in three different ways: PCI
first followed by surgery, surgery followed by PCI (two-stage HCR), or both
carried out during the same setting (single-stage HCR). In the era of primary
PCI for ST-segment elevation myocardial infarction (MI), it is probable that
patients requiring immediate PCI of the right coronary artery (RCA) or
circumflex artery as the culprit lesion may require subsequent surgical
revascularization of a complex LAD or left main lesion at some time in the
future. Hence, HCR, by definition, generally refers to a revascularization
strategy that has been strategically planned in a coordinated fashion by
interventional cardiologists and cardiac surgeons.
· The optimal revascularization strategy for
multivessel CAD is still debated. Although there are survival benefits of complete
arterial coronary revascularization, in practice only a fraction of patients
referred for CABG actually receive this; most of them receive at least one
saphenous vein graft (SVG). If it is true that recent trials, including
SYNTAX,1 have helped establish which anatomic categories are best addressed
with traditional CABG versus multivessel PCI with a drug-eluting stent (DES),
it is also true that there is still potential for prognostic and symptomatic
improvement from coronary revascularization in certain patients with
multivessel CAD. The modality depends on many factors, the most important of
which is the coronary anatomy itself. Other crucial factors include the
clinical setting (e.g., emergent, acute, chronic); left ventricular function;
degree of myocardial viability; and presence or absence of comorbidities,
assessed through the risk score of the Society of Thoracic Surgeons (STS) or
EuroScore (e.g., diabetes, associated valvular heart disease, presence of
calcification of the ascending aorta, which could preclude safe cross-clamping
during surgical intervention, age, patient preference, availability of bypass
conduits). Outcomes in diabetic patients, in particular, seem to favor a
surgical strategy over PCI for multivessel disease, although first-generation
sirolimus-eluting and paclitaxel-eluting stents were the predominant types of
DESs used in the FREEDOM trial and may underestimate the benefits of current
(third-generation) stenting.2
·
However, CABG is still considered the gold
standard treatment for patients with multivessel CAD.3-5 The major therapeutic
benefits of CABG arise from the graft of the LITA to LAD, which has been shown
to have excellent long-term results in terms of patency, event-free survival,
and relief of angina.6,7 On the other hand, SVGs have shown a high
incidence of failure8 as opposed to multivessel PCI with a DES,
which has shown lower restenosis rates, lower failure rates than SVG, and lower
stroke rates compared with CABG. In addition, PCI is less invasive and has a
shorter recovery time.9,10 HCR thus represents a promising coronary
revascularization option due to the fact that it offers the advantages of the
best of both treatment options. It takes advantage of the survival benefit
conferred by the LITA to LAD graft while minimizing the invasiveness of
revascularization therapy and providing a complete revascularization with PCI
to the non-LAD vessels. Additionally, the use of the robotic-assisted, coronary
artery bypass grafting (RA-CABG) graft of the LITA to the LAD minimizes
surgical trauma further.
·
Several studies have already demonstrated
similar results in terms of mortality, patency, and major adverse cardiac event
rates—between a hybrid revascularization strategy and similar conventional on-
and off-pump coronary bypass surgery.11-14 However, the safety and
effectiveness of HCR is still understudied and further studies, especially
randomized trials, are necessary before stronger recommendations can be made
for this revascularization therapy.
· HCR was first described by Angelini et al. in
1996.15 They used the classic minimally invasive direct coronary
artery bypass (MIDCAB) procedure, in which the LITA is harvested by direct
vision through a fourth interspace left minithoracotomy; the LITA is sutured to
the LAD on the beating heart. After the pioneering work of Benetti et al.16
on minimally invasive CABG, MIDCAB was adopted by several groups in the
mid-1990s.17-20 HCR then evolved as a result of the desire to treat
patients with multivessel disease effectively while at the same time lowering
procedure-related morbidity by combining minimal access coronary artery surgery
with percutaneous techniques.
· This was a very innovative and visionary new
concept in the field of coronary revascularization, representing a mix and the
natural evolution of the two disciplines, cardiac surgery and interventional
cardiology. Interventional cardiologists were progressively more aggressive in
their percutaneous treatment of CAD; surgeons were developing minimally
invasive techniques with a smaller incision, avoidance of sternotomy, and
beating heart surgery technique. Additionally, throughout the 1990s,
endoscopic, video-assisted, and finally robot-assisted LITA dissection were
performed. Successful endoscopic harvesting of LITA has been a crucial step in
the performance of minimal access coronary artery bypass surgery through
minithoracotomy incisions,21 and video-assisted LITA takedown has
been further facilitated by the use of robotic assistance. In the last 15
years, telemanipulation surgical systems have significantly improved, and
currently RA-CABG encompasses the use of robotic assistance to varying degrees,
from robotic-assisted LITA harvest to manual anastomosis through a mini
anterior non-rib spreading incision procedures to total endoscopic coronary
artery bypass (TECAB). On the other hand, there has been a continuous
improvement of DES performance and, in low-risk patients and those with
single-vessel disease, PCI can now provide comparable short- and mid-term
outcomes to those of CABG.22,23
·
According to the 2011 American College of
Cardiology/American Heart Association guidelines for CABG,24 HCR is a suitable
coronary revascularization strategy for patients with multivessel CAD (e.g.,
LAD and one or more non-LAD stenoses) and an indication for revascularization:
Hybrid revascularization is ideal in patients in whom technical or
anatomic limitations to CABG or PCI alone may be present and for whom
minimizing the invasiveness (and therefore the risk of morbidity and mortality)
of surgical intervention is preferred (e.g., patients with severe preexisting
comorbidities, recent MI, a lack of suitable graft conduits, a heavily
calcified ascending aorta, or a non-LAD coronary artery unsuitable for bypass
but amenable to PCI, and situations in which PCI of the LAD artery is not
feasible because of excessive tortuosity or chronic total occlusion).
1.
Recommendations From 2011 American College of Cardiology/American Heart
Association Guidelines for Coronary Artery Bypass Surgery24
◆ HCR, defined as the planned
combination of LITA to LAD artery grafting and PCI of one or more non-LAD
coronary arteries, is reasonable in patients with one or more of the following
(level of evidence: B):
◆ Limitations
to traditional CABG, such as heavily calcified proximal aorta or poor target
vessels for CABG (but amenable to PCI).
◆ Lack
of suitable graft conduits.
◆ Unfavorable
LAD artery for PCI (i.e., excessive vessel tortuosity or chronic total
occlusion).
◆ HCR,
defined as the planned combination of LITA to LAD artery grafting and PCI of
one or more non-LAD coronary arteries, may be reasonable as an alternative to
multivessel PCI or CABG in an attempt to improve the overall risk-benefit ratio
of the procedures (level of evidence: C). According to the 2014 European
Society of Cardiology/European Association for Cardio-Thoracic Surgery
guidelines on myocardial revascularization25:
Hybrid procedures consisting of LITA to LAD and PCI of other
territories appear reasonable when PCI of the LAD is not an option or is
unlikely to portend good long-term results or when achieving a complete
revascularization during CABG might be associated with an increased surgical
risk.
◆ HCR
may be clinically indicated in the following cases25:
1. Select patients with single-vessel disease of
the LAD, or in those with multivessel disease but with poor surgical targets,
except for the LAD territory, in whom minimally invasive surgery can be
performed to graft the LAD using the LITA. The remaining lesions in other are
subsequently treated by PCI.
2. Patients who had previous CABG and now require
valve surgery and who have at least one important patent graft (e.g., LITA to
LAD) and one or two occluded grafts with a native vessel suitable for PCI.
3. Combination of revascularization with
nonsternotomy valve intervention (e.g., PCI and minimally invasive mitral valve
repair, or PCI and transapical aortic valve implantation).
In addition, some patients with complex multivessel disease presenting
with STEMI initially require primary PCI of the culprit vessel, but
subsequently may require complete surgical revascularization. A similar
situation occurs when patients with combined valvular and CAD require urgent
revascularization with PCI. Finally, when a heavily calcified aorta is found in
the operating room, the surgeon may elect not to attempt complete
revascularization and to offer delayed PCI.25
◆ In
the Canadian Cardiovascular Society/Canadian Association of Interventional
Cardiology/ Canadian Society of Cardiac Surgery Position Statement on
Revascularization—Multivessel Coronary Artery Disease,26 it is stated that HCR:
1.
Is typically performed with minimally invasive
incisions.
2.
Combines the advantage of the LITA to LAD graft
with the less invasive nature of PCI.
3. Has been demonstrated by studies to date to be
safe and effective, but definitive data (e.g., randomized trials) are lacking.
◆ However,
the lack of randomized controlled clinical trials does not allow the
identification of an HCR target group of patients. Therefore, HCR should be
considered an alternative treatment strategy that should be tailored to the
individual patient based on the patient’s anatomy and patient-related variables
through a collaborative heart team approach. The ideal patient is a patient
with multivessel CAD, with a complex proximal LAD lesion suitable for LITA-LAD
grafting, associated with non-LAD lesions suitable for PCI, and no
contraindications for dual antiplatelet therapy (Fig. 6.1). Careful attention
should be focused on the quality and size of the LAD, epicardial or
intramyocardial LAD course (Fig. 6.2), presence of large diagonal vessels,
which can be mistaken as the LAD and inadvertently grafted, complexity of
non-LAD vessel lesions for PCI, and number of stents necessary to treat the
non-LAD stenosis effectively. PCI of overly complex non-LAD vessels (e.g., long
lesions, bifurcations of major branches) will increase the risk of restenosis
and may diminish the benefits of a percutaneous strategy over saphenous vein or
other arterial grafting.
◆ Other
important factors in patient selection for HCR are patient variables, including
clinical presentation, comorbidities, body habitus, chest wall anatomy, and
surgeon experience with minimally invasive CABG procedures. Chest wall anatomy,
obesity, and thoracic size may have a significant impact on the surgical part
of the procedure. Patient comorbidities, such as chronic obstructive pulmonary
disease and pulmonary hypertension, also have a significant impact. For a
robotic-assisted approach, the patient must be able to tolerate single-lung
ventilation and physiologic changes related to carbon dioxide insufflation.
HCR could then serve patients at the two extremities of the risk spectrum young
and relatively healthy patients who prefer to avoid the sternotomy but do not
want to renounce the durability of the LITA- LAD graft, and older and/or
high-risk patients who may benefit from a less traumatic, minimally invasive
but full and complete coronary revascularization. In the end, it is quite
intuitive that the experience of the surgeon is a key factor in the successful
outcome of this revascularization strategy, given the challenging nature and
steep learning curve of the minimally invasive CABG techniques (from RA-CABG to
TECAB).
 |
Figure 6.1 This coronary angiogram shows an example of an ideal
candidate for hybrid coronary revascularization. (A) Focal lesion of the
circumflex artery. (B) Complex, tandem lesion of the left anterior descending
coronary artery. (C) Focal lesion of the right coronary artery.
Figure 6.2 The arrow indicates the epicardial course of
the left anterior descending coronary artery.
|
· A minimally invasive coronary artery bypass
procedure is done first (Fig. 6.3). The patient remains on aspirin
preoperatively, intraoperatively, and postoperatively. After harvest of the
LITA, bivalirudin at a loading dose of 0.75 mg/kg is administered; infusion at
a rate of 1.75 mg/kg/hr is continued throughout the rest of the procedure,
including the surgical revascularization and PCI. After the surgical
revascularization is completed, the hybrid operating room is then reset to a
cardiac catheterization configuration. The LITA graft check is performed. After
hemostasis is confirmed, with evidence of minimal drainage from chest tubes,
clopidogrel, 600 mg, or ticagrelor, 180 mg via a nasogastric (NG) tube, is
administered (Fig. 6.4). PCI is performed on non-LAD targets. The bivalirudin
infusion is continued and overlapped with the clopidogrel over the next hour.
Postoperatively, the patient is continued on aspirin and clopidogrel or
ticagrelor.
· If PCI has already been performed on the culprit
non-LAD vessel, then after 3 months the clopidrogrel or ticagrelor are held for
2 days prior to the surgery but not the ASA. The dual antiplatelet therapy is
restarted the day after surgery. Minimally invasive surgical revascularization
is performed as per routine using heparin and protamine for reversal. If PCI is
to be performed postoperatively, the evening after surgery the patient is given
a loading dose of clopidogrel or ticagrelor; the patient undergoes PCI on the
next day. Postoperatively, the patient is continued on aspirin and clopidogrel
or ticagrelor.
·
A paravertebral or intrathecal block with
epimorphine is used for pain control.
·
Defibrillator pads on the left scapula and
inferior and medial to the right breast are placed.
·
Intubation is performed with a double-lumen
endotracheal tube (ETT) to deflate the left lung.
· Alternatively, a single-lumen ETT and bronchial
blocker may be placed under fiberoptic guidance.
· Lines are routine; they include an arterial line
and pulmonary artery catheter (PAC), if required. If peripheral access is
limited, 16-G IV tubing should at least be placed. A triple-lumen catheter is
placed if no PAC is inserted.
· After intubation, place a bronchial blocker into
the mainstream bronchus with fiberoptic guidance. Place the proximal end of the
balloon approximately 1 to 2 cm below the carina.
·
A warming blanket should be used to avoid
hypothermia.
·
CO2 insufflation is provided to
maintain an intrathoracic pressure of 5 to 10 mm Hg (watch blood pressure).
· Hemodynamic support for off-pump coronary artery
bypass (OPCAB) surgery may be necessary.
 |
Figure 6.3 The flow chart indicates the procedural algorithm of
the single- or two-stage hybrid coronary revascularization.
Figure 6.4 Anticoagulation and antiplatelet therapy strategy in
single stage hybrid coronary revascularization.
|
·
Deliver approximately 10 mL/kg of tidal volume
prior to and during single-lung ventilation. Tidal volume may need to be
decreased because large tidal volumes can cause shifting of the mediastinum,
which may cause the stabilizer to slip and effect the stabilization.
·
Keep the O2 saturation greater than
90%. If the saturation begins to decrease, the following should be carried out:
•
Add continuous positive airway pressure (CPAP)
of 5 cm H2O to the deflated lung. This can be performed through the
bronchial blocker by inserting a 7 Frendotracheal tube (ETT)
connector into the barrel of a 3-mL syringe. Insert the syringe tip into the
lumen of the bronchial blocker. Attach the 7 ETT connector to a CPAP circuit.
•
CPAP can be increased but if it is increased too
much it will cause the lung to inflate and obscure the surgeon’s view.
· The need for extracorporeal support is rare. A
supported coronary revascularization would only require a system with a venous
reservoir, arterial pump, oxygenator, and filter. It is recommended that the
extracorporeal support system and devices be on standby. The use of a cell
saver is recommended. Percutaneous cannulae are necessary if femoral cannulation
is used for hemodynamic support.
◆ Initial
positioning of the patient can have a considerable effect on the operative
procedure because proper positioning minimizes interference from internal and
external body structures by the robotic equipment. Judicious care at this stage
ensures the necessary landmarks for port placement to maximize intraoperative
robotic arm maneuverability.
◆ The
patient is positioned at the left edge of the operating room table. A
comfortable support is placed under the distal two-thirds of the left side of
the patient’s thorax. This usually takes the form of a rolled-up towel and
should elevate the patient’s thorax by 6 to 8 inches superiorly. The left arm
is positioned at the side of the operating room table to allow the left
shoulder to drop posteriorly. Rotate the table 30 degrees up so the patient is
in the partial left lateral position (Fig. 6.5). Leads and external
defibrillator pads are positioned on the patient’s chest, away from the left
lateral and midclavicular areas of the thorax, so as not to interfere with port
placement. Place one pad on the right anterior lateral thorax and the other on
the left posterior thorax. The patient is prepped in a routine manner for
conventional CABG and saphenous vein harvesting, safeguarding against the
possibility of having to convert the case to an open procedure. The only
variation in preparation is exposure of the patient’s thorax and axilla on one
side for port placement.
 |
Figure 6.5 Proper patient positioning.
Direct Internal
Thoracic Artery Harvest
·
Lines and airway double-lumen ETT with internal
jugular central line.
·
Positioning is 30 degrees right lateral
decubitus, with a roll under the left shoulder.
·
Perform a 5- to 7-cm anterolateral
minithoracotomy.
·
Male patients over the fifth or sixth
intercostal space (ICS), one-third medial to the nipple.
·
Female patients inframammary incision in similar
location.
·
Medial two-thirds of the window incision medial
to the anterior axillary line.
·
Deflate left lung while making incision.
· Divide intercostal muscles laterally to reduce
risk of rib fracture, then divide them medially to avoid damage to LITA.
·
Soft tissue retractor may be placed in incision
to maximize access.
·
Place a large Kelly clamp with a sponge in the
sixth ICS to assist with harvesting the LIMA. Use the sponge to push away
tissue for better internal thoracic artery (ITA) visualization.
· Insert the ThoraTrak (Medtronic, Minneapolis)
retractor system into the ICS incision; then hook the ThoraTrak retractor
system to the Rultract Skyhook surgical retractor (Pemco, Cleveland) to
facilitate the LITA harvest.
· To prevent crush injury to the LIMA, make sure
that the superior portion of the retractor is placed and maintained in the
lateral aspect of the incision.
· Care should be taken not to fracture a rib.
· The ThoraTrak MICS retractor system should be
opened slowly, which allows tissue and bone to acclimate to the change in
position to minimize the potential for rib fracture and pain.
·
Start the LITA harvest at the third ICS using
direct vision through the window incision.
· Use an extended electrocautery instrument,
endoscopic forceps, suction, endoscopic clip applier, and small clips for the
harvest.
·
Complete the harvest up to the subclavian vein
and down past the left fifth ICS.
·
Take care to identify and avoid the phrenic
nerve.
·
During the LITA harvest, flexing the table may
facilitate access to the superior portion of the LITA.
·
Anchor the pedicle of the LITA with silk ties to
maintain the proper orientation.
·
Give intravenous bivalirudin or heparin prior to
LITA division.
Artery and/or Right Internal Thoracic Artery
Step 1. Patient Setup
·
Positioning is 30 degrees right lateral
decubitus, with a roll under the left chest to allow the shoulders to fall.
·
Proper port placement is fundamental to the success
of the operation. Placement of each port is centered on constructing an ideal
configuration that ensures mobilization of the ITAs from the first to the sixth
ribs, with the least amount of impedance to the robotic arms. It is imperative
that the surgeon be meticulous with each individual patient, taking the
necessary time needed to ensure proper completion of port placement prior to
surgery. Suboptimal port placement can frequently result in dangerous internal
and/or external robotic arm collisions.
· The lack of intrathoracic visualization is the
premiere challenge to determining port placement. Careful review of the
coronary angiogram, chest radiographs, and computed tomography (CT) scans of
the heart with contrast preoperatively, along with direct examination of the
anatomic structures of the individual patient in the operating room, help
alleviate this problem.
·
Evaluate the chest radiograph in an orderly
manner. Identify pertinent thoracic landmarks— suprasternal notch; angle of Louis;
xiphoid; second to fifth ICSs; LITA and right internal thoracic artery (RITA)
locations, 1 to 3 cm lateral to the sternum.
·
Note the position of the heart in the
mediastinum. Note the size of the heart in relation to the pleural space on the
port access side of the chest. On the lateral view, observe the degree of space
between the anterior surface of heart and underside of the thorax.
· Assess the intrathoracic space. The distance
from the pleural surface to the mediastinum cannot be less than 1.7 cm at the
camera port space, which is usually the fifth ICS (Fig. 6.6). A distance less
than 1.7 cm will not provide adequate intrathoracic space for adequate degrees
of freedom of the robotic instrument.
•
Rule out any other anatomic abnormalities, such
as asbestos plaques.
• Determine the anteroposterior (AP) measurement
and transverse (Trv) distance of the chest cavity. If the AP/Trv ratio is less
than 45%, it reduces the success of robotic-assisted coronary artery
revascularization.26 In addition, the vertical distance from the LAD
to the chest wall is also a factor in the success of the operation. If this
distance is less than 15 mm, there is a lower chance of being able to perform
the operation robotically27 (Fig. 6.7).
•
Assess the location of the coronary arteries if
intramyocardial. Access to intramyocardial vessels for revascularization is
challenging and can result in conversion (Fig. 6.8).
 |
Figure 6.6 Computed tomography showing the distance from the
pleura to the mediastinum.
Figure 6.7 Anteroposterior (AP), transverse measurement (TVR),
and left anterior descending (LAD) to chest wall distance.
Figure 6.8 Intramyocardial location of left anterior descending (LAD)
coronary artery.
|
Direct xamination
of the Patient Thorax
·
Evaluate the external anatomic characteristics
of the patient’s thorax, and conceptualize the internal anatomic
characteristics based on the previously viewed chest x-ray, CT scans, and
preoperative coronary angiogram.
·
With a felt marker, outline precisely where each
port is to enter the thoracic cavity, using the standardized guidelines
discussed in the following (see Fig. 6.5). Make necessary adjustments for
individual patients based on information acquired from diagnostic imaging and
the patient examination.
·
The left lung is deflated, and the 12-mm port is
inserted in the fifth ICS.
·
CO2 insufflation is provided to
maintain an intrathoracic pressure of 5 to 10 mm Hg (watch blood pressure).
· A 30-degree endoscope is inserted. Under guidance
of the endoscope, two 7-mm ports are inserted in the third and seventh ICSs.
·
The LITA is harvested from the first to the
sixth rib endoscopically or robotically.
· Prior to ligation of the LITA, the patient is
given intravenous bivalirudin or heparin depending on the stage of the
procedure (1 or 2).
·
The LITA pedicle is transected. To avoid
torsion, using a clip, it is attached to the edge of the pericardium in the
normal anatomic orientation at the site where the anastomosis is to be
performed.
·
The LITA-LAD anastomosis is performed under
direct vision through the minithoracotomy.
·
Only soft tissue retraction is generally
required, minimizing trauma.
◆ Pericardial
fat is first removed.
◆ The
pericardium is opened down to the diaphragm and toward the right pleura, 2 to 3
cm anterior to the phrenic nerve.
·
The LAD artery is identified based on its
location on the ventricular septum, going to the apex.
·
Insert the long needle under direct
visualization of the endoscope to identify the optimal ICS to perform a
thoracotomy for best exposure of the LAD.
·
Insufflation can be momentarily stopped to take
away the shift in the mediastinum.
·
Mark the intercostal space from the inside using
electrocautery.
·
If robotic assistance is used, the robot is
undocked and instrument ports are removed.
·
A mini anterior thoracotomy is performed.
·
Identify the pericardiotomy site and ITA
pedicle.
·
Detach the ITA, deliver through an incision, and
immediately place two suspension sutures to prevent the pedicle from twisting.
·
Assess ITA length and flow and prepare for
anastomosis.
·
Select the port site for the endoscopic Octopus
Nuvo stabilizer (Medtronic, Minneapolis; Fig. 6.9) sixth ICS if the LITA is
harvested directly or the fifth ICS port site if the LITA is robotically
harvested.
·
Achieve stabilization.
· Apply proximal and distal occlusion snares or an
intravascular shunt, depending on the patient’s hemodynamics.
·
Perform anastomosis in the usual fashion.
·
Check graft flow using an intraoperative
flow-measuring device.
·
Carry out intraoperative angiography to check
ITA patency and PCI of other coronary vessels at the same time (if one-stage
procedure) in the specialized hybrid operating room (Fig. 6.10).
 |
Figure 6.9 Octopus Nuvo stabilizer.
Figure 6.10 Hybrid cardiac operating room at the London Health
Sciences Centre and Canadian Surgical Technologies and Advance Robotics (CSTAR).
The room is fully equipped for robotic surgery, angiography, and percutaneous
coronary intervention.
|
·
Since 2004, at the London Health Sciences
Centre, a total of 153 consecutive patients (age, 61.4 ± 11.1 years; 118 males
and 35 females) underwent HCR (robotic-assisted MIDCAB graft of the LIMA to the
LAD and PCI in a non-LAD vessel), 120 of which were a single simultaneous
procedure. Of the remainder undergoing staged procedures, 19 patients underwent
PCI before surgery, and 14 patients underwent PCI at a separate setting after
surgery. Successful HCR occurred in 146 of the 153 patients; 7 patients
required intraoperative conversion to conventional coronary bypass. DESs were
used in 139 patients, and 14 patients were treated with bare metal stents. In
the series of patients who underwent successful HCR, no perioperative mortality
occurred; there was only one perioperative MI (0.6%), two cerebral vascular
accidents (1.3%), and one respiratory failure with prolonged ventilation
(0.65%). The rate of reoperation for bleeding was 2.6% (n = 4). Only
13.0% of patients (n = 20) required a blood transfusion. None of the
patients developed acute kidney injury (AKI) with a need for kidney replacement
therapy. The average intensive care unit (ICU) stay was 1 ± 1 days and the
average hospital stay was 4 ± 2 days. Coronary angiography follow-up at 6
months was performed in 95 patients. Angiographic evaluation demonstrated an
LITA anastomotic patency of 97.9% and a PCI vessel patency of 92.6%. Clinical
follow-up at 83.6 ± 11.1 months demonstrated 93.9% survival, 91.2% freedom from
angina, and 88.5% freedom from any form of coronary revas- cularization. PCI to
LITA to LAD anastomosis was performed in 5 patients; in one case, the
anastomosis was surgically revised, and PCI was repeated to non-LAD vessels in
11 patients.
◆ We
also performed a comparative analysis of HCR to conventional on-pump CABG with
an adjusted analysis using inverse probability weighting (IPW) based on the
propensity score of undergoing on-pump CABG or HCR from patients in our
institution. We considered all double on-pump CABG (n = 682) and HCR
(147 RADCAB grafts of the LITA to the LAD and PCI to one of non-LAD vessels)
procedures between March 2004 and November 2015. We performed IPW-adjusted
analysis of the outcomes using the teffects ipw package (for estimating
treatment effects) using the average treatment effect (p < 0.05 was
considered significant). In the two groups, there were no statistically
significant difference in the rate of re-exploration for bleeding (CABG, 1.7%;
HCR, 2.8%; p = 0.44), perioperative MI (CABG, 1.1%; HCR, 1.4%; p =
0.79), stroke (CABG, 2.4%; HCR, 2.1%; p = 0.83), need for hemodialysis
(CABG, 0.4%; HCR, 0%; p = 0.16), prolonged mechanical ventilation (CABG,
2%; HCR, 0.7%; p = 0.15), ICU length of stay (CABG, 1.7 ± 2.3 days; HCR,
1.0 ± 0.8 days; p = 0.23). HCR was associated with a lower blood
transfusion rate (CABG, 25%; HCR, 14%; p = 0.002), lower in-hospital
mortality (CABG, 1.3%; HCR, 0%; p = 0.008), shorter hospital length of
stay (CABG, 6.7 ± 4.7 days; HCR, 4.5 ± 2.1 days; p < 0.001). After
the median follow-up period of 70 months (37–106 months; CABG group), and 96
months (53–114 months; HCR group) there was no significant difference in
survival (CABG, 92%; HCR, 97%; p = 0.13) and freedom from any form of
revascularization (CABG, 93%; HCR, 91%; p = 0.27). HCR was superior in
freedom from angina (CABG, 70%; HCR, 91%; p < 0.001). Using the same
methodology, we also performed a comparative analysis to off-pump CABG. Our
sample consisted of all double off-pump CABG (n = 216) and HCR (147
RA-CABG grafts of the LITA to the LAD and PCI to one of non-LAD vessels)
procedures performed between March 2004 and November 2015.
◆ We
found that in the two groups, there were no statistically significant
differences in the rate of re-exploration for bleeding (CABG, 1.5%; HCR, 3.5%; p
= 0.36), postoperative atrial fibrillation (CABG, 19%; HCR, 12%; p =
0.13), perioperative MI (CABG, 0.5%; HCR, 1.4%; p = 0.36), stroke (CABG,
1.0%; HCR, 2.1%; p = 0.88), renal failure with need for hemodialysis
(CABG, 0.5%; HCR, 0%; p = 0.31), blood transfusion (CABG, 28%; HCR, 15%;
p = 0.60), in-hospital mortality (CABG, 1.0%; HCR, 0%; p = 0.15),
ICU length of stay (CABG, 1.8 ± 1.3 days; HCR, 1.0 ± 0.8 days; p =
0.10). There was a higher rate of in-hospital re-intervention in the HCR group
in order to revise the LITA-LAD graft after intraoperative angiography (CABG,
0%; HCR, 3.4%; p = 0.029). HCR resulted in a lower incidence of
postoperative prolonged mechanical ventilation (CABG, 4%; HCR, 0.7%; p =
0.017). The hospital length of stay was significantly shorter in patients who
underwent HCR (CABG, 8.1 ± 5.8 days; HCR, 4.5 ± 2.1 days; p < 0.001).
After the median follow-up periods of 81 months (48–113 months; CABG group) and
96 months (53–115 months; HCR group) there was no significant difference in
survival (CABG, 85%; HCR, 96%; p = 0.054) and freedom from any form of
revascularization (CABG, 92%; HCR, 91%; p = 0.80). HCR was superior in
terms of freedom from angina (CABG, 73%; HCR, 90%; p < 0.001).
· Our experience and that of others has suggested
that a hybrid revascularization strategy is safe and provides excellent short-
and long-term results, with a low rate of postoperative complications, shorter
hospital stay, fast recovery time, and very good rates of freedom from angina,
freedom from any revascularization, and long-term survival. In recent years,
there has been an increasing trend toward hybrid revascularization procedures
due to a continuous improvement of DES performance and a broader use of
minimally invasive techniques, especially with robotic assistance.
· The major advantages of HCR when compared with
conventional CABG are the avoidance of cardiopulmonary bypass, aortic clamping,
and sternotomy while still providing the survival benefit of the LITA-LAD
anastomosis. With the addition of PCI, complete revascularization of all
significantly diseased arteries is ensured.
· However, if the rationale behind this
alternative form of coronary revascularization is well established, HCR has
failed to be broadly adopted so far. The STS adult cardiac surgery database has
shown that from July 2011 to March 2013, HCR represented only 0.48% of the
total CABG volume (950 of the total of 198,622 patients who underwent CABG).30
The reasons why physicians and surgeons have not currently embraced this in
routine clinical practice could be related to the fact that minimally invasive
LITA-LAD anastomosis construction is technically demanding, and there are still
costs and logistical problems associated with performing two procedures with different
periprocedural management protocols. There is also a lack in validation from
randomized clinical trials comparing HCR with conventional CABG. However, a few
recent studies have highlighted the good preliminary results of this technique,
including its advantages and disadvantages. Harskamp et al. reported the first
meta-analysis of more than 1100 patients who underwent HCR from six
observational cohort studies.31 They observed that patients
undergoing HCR have a similar risk of the composite of death, MI, stroke, and
repeat revascularization as those treated with CABG during hospitalization and
follow-up (4.1% of patients after HCR and 9.1% of patients with CABG at 1-year
follow-up). Death, MI, and stroke rates were numerically but not statistically lower
with HCR. The need for repeated revascularization occurred more frequently with
HCR (8.3% of patients after HCR and 3.4% of patients after CABG at 3-year
follow-up; p < 0.001). These findings were similar when HCR was
performed as a single- or dual-stage procedure.
· The data generated by this meta-analysis also
support the finding that HCR performed without conventional sternotomy results
in a shorter duration of hospital stay, earlier return to work, and fewer
in-hospital complications. It also showed that self-reported quality of life is
significantly higher at follow-up. These data are in line with our findings. In
our analysis, we observed a shorter length of stay in the ICU (1 ± 1 days) and
average hospital stay of 5 ± 2 days. None of our patients developed renal
failure with the need for dialysis, and only 13.2% of patients required a blood
transfusion. We also observed a lower rate of repeat revascularization, with a
very good long-term freedom from any revascularization (in 90.7% of patients at
clinical follow-up of 77.8 ± 41.4 months). The results of new-generation DESs
are playing an important role in coronary revascularization and could
contribute to a wider diffusion of HCR. The use of newer DESs show favorable
outcome,32-34 especially if compared with the results of first generation
stents and venous grafts, which are more prone to atherosclerotic degeneration
and progressive narrowing, with high early and long-term failure rates, as
shown in the PREVENT IV study.8
· In another meta-analysis, Zhu et al. analyzed
data from 10 cohort studies involving 6176 patients.11 They calculated the
summary odds ratio (OR) for primary endpoints (e.g., death, stroke, MI, target
vessel revascularization, major adverse cardiac or cerebrovascular events) and
secondary endpoints (e.g., atrial fibrillation, renal failure, length of stay
in the ICU, length of stay in hospital, red blood cell transfusion). They found
that HCR was noninferior to CABG in terms of major adverse cardiac or
cerebrovascular events during hospitalization (OR, 0.68; confidence interval
[CI], 0.34–1.33) and at 1-year follow-up (OR, 0.32; CI, 0.05–1.89). No significant
difference was found between the HCR and CABG groups in regard to in-hospital
and 1-year follow-up, outcomes of death, MI, stroke, atrial fibrillation, and
renal failure. However, HCR was associated with a lower requirement for blood
transfusions and shorter length of stay in the ICU and length of stay in
hospital than CABG (weighted mean difference, −1.25; 95% CI, −11.62–10.88;
−17.47, −31.01–3.93; −1.77, −3.07 to −0.46, respectively). Harskamp et al.
compared HCR versus standard CABG using a propensity score matching algorithm.12
They studied 306 patients who underwent HCR and matched them in a 1 : 3 ratio
to 918 patients who underwent standard CABG. They found that the 30-day
composite of death, MI, or stroke after HCR and CABG was 3.3% and 3.1%,
respectively (OR, 1.07; 95% CI, 0.52–2.21; p = 0.85). HCR was associated
with lower rates of in-hospital major morbidity (8.5% vs. 15.5%; p =
0.005), lower blood transfusion use (21.6% vs. 46.6%, p < 0.001),
lower volume of chest tube drainage (690 mL; 25th–75th percentile—485–1050 mL
vs. 920 mL, 25th to 75th percentile; 710–1230 mL; p < 0.001), and
shorter postoperative length of stay (<5-day stay—52.6% vs. 38.1%; p =
0.001). during the 3-year follow-up period. Mortality was similar after HCR and
CABG (8.8% vs. 10.2%; hazard ratio = 0.91; 95% CI, 0.55–1.52; p = 0.72).
· Only one small randomized controlled trial
comparing HCR with CABG has recently emerged in the medical literature.35
In this study, a total of 200 patients with multivessel CAD involving the LAD
and a critical lesion in at least one major epicardial vessel amenable to PCI
and CABG and referred for conventional surgical revascularization were randomly
assigned to undergo HCR or CABG in a 1 : 1 ratio. The primary endpoint was the
evaluation of the safety of HCR. The feasibility was defined by the percentage
of patients with a complete HCR procedure and the percentage of patients with
conversion to standard CABG. They also assessed the occurrence of major adverse
cardiac events such as death, MI, stroke, repeated revascularization, and major
bleeding within a 12-month follow-up period. Of the patients in the HCR group,
93.9% had complete HCR, and 6.1% patients were converted to standard CABG. At
12 months, the rates of death (2.0% vs. 2.9%, p = not significant [NS]),
MI (6.1% vs. 3.9%; p = NS), major bleeding (2% vs. 2%; p = NS),
and repeat revascularization (2% vs. 0%; p = NS) were similar in the two
groups; no cerebrovascular accidents were observed.
· Patient selection is another crucial factor for
HCR. We cannot emphasize enough the importance of the heart team in guiding
appropriate patient selection for HCR. The ideal patient is a patient with
multivessel CAD with a complex proximal LAD lesion suitable for LITA-LAD
grafting, associated with significant but not overly complex non-LAD lesions
suitable for PCI, with no contraindications for dual antiplatelet therapy. The
high likelihood of achieving a complete revascularization with such an approach
is certainly one of the most important guiding factors. Complex distal left
main lesions may be suitable and ideal for HCR if the circumflex artery
territory is amenable for PCI. As noted, the lack of large randomized
controlled trials, however, does not allow the identification of an optimal HCR
target group of patients.
· Another important factor is the choice of proper
timing for the two procedures. In other words, it should be determined if it is
better to perform the one-stage treatment of CAD (simultaneous HCR) or in two
separate settings (two-stage HCR). Most of our patients (71.9%) underwent
single-stage HCR. The decision is guided by patient characteristics and
available facilities, but we acknowledge that this approach has several
advantages, including that it is more cost-effective, reduces the length of
stay, increases patient satisfaction, and allows the immediate confirmation of
the patency of the LITA graft. The main disadvantage is the risk of bleeding
due to the use of dual antiplatelet therapy. For this approach, an equipped
hybrid operating room is mandatory. The two-stage procedure is generally
favored based on clinical presentation and anatomy. PCI as the initial
procedure, followed by CABG, is usually encountered in the setting of acute
coronary syndrome when the non-LAD culprit lesion is initially addressed in the
catheterization laboratory.
· Another disadvantage is the risk of bleeding due
to the uninterrupted antiplatelet therapy when the patient undergoes the subsequent
surgical LITA anastomosis. In the two-stage approach, we generally prefer
performing LITA-LAD bypass grafting before PCI when clinically appropriate. The
main advantages of this strategy are the immediate angiographic check of the
LITA-LAD anastomosis at the same time as the PCI, protection of the anterior
wall of the left ventricle, which lowers the risk of PCI and, theoretically,
the decreased risk of bleeding, considering that full
antiplatelet therapy is not initiated prior to surgery. One of the major
perioperative concerns of HCR is management of antiplatelet therapy, with the
related risk of bleeding or stent thrombosis. In our series, we observed only
one subacute stent thrombosis; this occurred in our early experience, when
heparin was overlapped with bivalirudin. One of the arguments against HCR has
been that the LITA-LAD anastomosis is technically highly demanding, and this
could interfere with its patency rates. We previously reported two studies with
angiographic follow-up of patients who underwent HCR. In the first study of 58
patients undergoing HCR,36 at a mean follow-up of 20.2 months, the
LITA-LAD anastomosis was patent in 49 of the 54 patients who had repeat
catheterization (91%). Later, in 2014, we published a series of 94 patients who
underwent HCR and had angiographic follow-up at 6 months illustrating a 94%
anastomotic patency of the LITA-LAD.37 This compares favorably with
the LITA patency seen with conventional surgery.
Keywords : coronary revascularization, hybrid, PCI, minimally
invasive CABG robotic, Operations for Coronary Artery Disease
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