Minimally Invasive,
Mini-Thoracotomy Aortic
Valve Replacement
Figure 10.1 Femoral arterial and venous cannulation. |
Keywords: minimally invasive, minithoracotomy, aortic valve replacement, Operations for Valvular
Heart Disease
Step 1. Introductory Considerations
· Minimally invasive valve surgery has numerous
benefits compared with a standard median sternotomy. These benefits include
reduced surgical trauma, blood loss, transfusion requirements, and
reoperations for bleeding. Ventilation times and intensive care unit and
hospital lengths of stay are also reduced. Patients undergoing minimally
invasive surgery also experience a more rapid return to functional capacity and
less use of rehabilitative resources, which has resulted in additional costs
savings as well.1-5
· The incisions and approaches used in minimally
invasive aortic valve surgery have evolved over time. The concept was first
introduced in 1996 by Cosgrove et al.,6 who described a right
parasternal incision approach. This later proved to cause significant chest
wall instability and has since been abandoned. Currently, minimally invasive
aortic valve surgery is usually performed via an upper hemisternotomy approach,
either with a T or L transection of the sternum at the level of the third or
fourth intercostal space.7,8 A lower hemisternotomy and manubrial
approach have also been described.9,10 The only true sternal-sparing
procedures are an axillary approach or right minithoracotomy, entering the
thoracic cavity via the second or third intercostal space.11 The
focus of this chapter will be on the latter method.
· The right minithoracotomy can be used in most
subsets of patients requiring an aortic valve replacement (AVR). Definitive
contraindications to a right anterior thoracotomy approach include patients
with a severely calcified aorta (porcelain aorta), evident preoperatively by
cardiac catheterization or computed tomography (CT) scan or intraoperatively by
palpation, patients who cannot be safely cannulated peripherally due to
peripheral vascular disease or centrally
due to calcium in the aorta, and patients who require a valve-sparing
operation. The aforementioned
groups require greater exposure of the operative field. Patients who present
with previous right thoracic surgery or dense adhesions from an inflammatory
reaction may undergo a minithoracotomy approach. In this particular group,
minimal dissection is performed in the pleural cavity, and the pericardial
space is immediately entered and exposed.
· The benefits of the minithoracotomy over a
standard sternotomy AVR have also been seen in higher-risk patients, including
older patients (> 75 years old),1 obese patients (body mass index
[BMI] > 30 kg/m2),2 patients with chronic obstructive pulmonary
disease (COPD),4 and patients with a low ejection fraction (< 35%). Several
studies have demonstrated a lower morbidity and mortality in these higher-risk
patients.12 An extended application of this procedure can be offered
to patients who require replacement of the ascending aorta and hemiarch along
with an AVR.13 Most of these procedures are performed under deep
hypothermic circulatory arrest and retrograde cerebral perfusion. In patients
requiring a full root replacement due to aneurysmal disease or a small aortic
annulus, an aortic root replacement with reimplantation of the coronaries can
also be performed. In addition, reoperative aortic valve surgery in patients
with prior valve surgery or coronary revascularization via a right
minithoracotomy approach is feasible.14,15 All these procedures are
more technically challenging and require additional experience. Other
applications include AVR with aortic root enlargement, AVR with a septal
myectomy, and AVR with a single bypass to the proximal or distal right coronary
artery (RCA). The posterior descending artery is difficult to visualize with
this approach. In patients with coronary artery disease amenable to
percutaneous intervention, a hybrid approach is preferable. A percutaneous
intervention can be performed at any time prior to the minimally invasive valve
surgery. A minithoracotomy approach can be offered to patients receiving dual
antiplatelet therapy.16,17
· The preoperative workup includes routine blood
work, chest radiography, cardiac catheterization, and echocardiography. A
routine CT angiogram is not necessary unless severe peripheral vascular disease
is suspected by history or physical examination, although a CT angiogram is
highly recommended when initiating a minimally invasive program. Stroke rates
are low in patients undergoing femoral cannulation, despite the use of
retrograde arterial perfusion,18,19 and are comparable to rates in
patients undergoing a sternotomy valve procedure.
· Routine CT scans of the chest are not necessary
either, although others have defined inclusion criteria based on CT scan
findings, which may be beneficial initially.5 Chest CT scans may also
potentially diminish the incidence of conversions.
· The anatomy of certain patients can pose
additional challenges when performing the procedure via a right minithoracotomy
approach. A chest x-ray demonstrating the right border of the heart adjacent to
the right border of the vertebral column may be associated with the heart being
displaced toward the left side of the chest. This is also true for patients
with a pectus excavatum. If the angle of the aorta and ventricle lie at 90
degrees on the ventriculogram (cardiac catheterization), visualization of the aortic
valve may be more challenging. Visualization of the aortic valve is usually
more challenging in patients with a bicuspid aortic valve. Although
challenging, these anatomic variants are not definitive contraindications for
the surgery.
· A single-lumen endotracheal tube is inserted,
and double-lung ventilation is used throughout the operation. If visualization
of the heart is impaired by the lungs, the lungs are temporarily deflated, or
cardiopulmonary bypass can be initiated early in the procedure.
· Single-lung ventilation with a double-lumen
endotracheal tube or bronchial blocker is not performed unless significant
pleural adhesions limit visualization and dissection. Cases of unilateral
reexpansion pulmonary edema secondary to single-lung ventilation have been
reported.20
5.
Monitoring Lines
· The preoperative preparation includes insertion
of a left radial arterial line and right internal jugular or left subclavian
vein Swan-Ganz catheter. A left radial arterial line is always preferred in case
right axillary artery cannulation is required. Patients undergoing reoperative
aortic valve surgery will have a temporary transvenous pacemaker inserted after
the induction of anesthesia.
6.
Anesthesia
· The patient is induced with a muscle relaxant
(fentanyl and midazolam). A volatile agent is administered throughout the
surgery. Remifentanil is started immediately prior to exposing the artery and
vein for cannulation. Heparin (300-400 units/kg) is also given at this time in
preparation for cannulation. The dosage of remifentanil is increased prior to
the chest incision. While on cardiopulmonary bypass, the remifentanil dose is
lowered, and midazolam is administered. After weaning from cardiopulmonary
bypass, remifentanil is continued at a low dose. At completion of the
operation, the patient is transported to the intensive care unit and continued
on remifentanil.
· Every patient should have a thorough
intraoperative two-dimensional (2D) and three-dimensional (3D) transesophageal
echocardiographic assessment. The sizes of the aortic annulus and ascending
aorta are measured. Left ventricular function is assessed. The mitral valve is
visualized and analyzed. If mitral valve pathology requiring repair or
replacement is identified, patient positioning may need to be changed.
Assessment of atherosclerotic disease in the ascending and descending aorta is
performed. Evidence of a grade 4 or 5 free-floating atheroma in the descending
aorta would preclude femoral cannulation and retrograde arterial perfusion.
Positioning of the venous cannula in the superior vena cava (SVC) is performed
with trans-esophageal echocardiography (TEE). A bicaval midesophageal view done
at 80 to 100 degrees is used for placement of the venous cannula into the SVC.
TEE is also used in reoperative aortic
valve surgery for insertion of a retrograde cardioplegia cannula. A
midesophageal, four-chamber view
at 0 degrees is used for guiding placement of a retrograde cannula into the
coronary sinus if necessary.21
· Intraoperative fluoroscopy can also be used to
aid placement of the venous guidewire and cannula when the wire cannot be
visualized by TEE. Intraoperative iliac and abdominal aortic angiograms with
fluoroscopy are obtained when there is uncertainty after insertion of the
femoral arterial cannula or when calcified plaques are encountered during
cannulation.
Figure 10.3 Right mini
thoracotomy exposure with soft tissue retractor and rib spreader.
Figure 10.4 Left
ventricular vent in right superior pulmonary vein.
· Patients receive 2 g of a cephalosporin within
1 hour of skin incision and every 8 hours thereafter for 48 hours. Patients
allergic to penicillin receive 1 g of vancomycin within 1 hour of skin incision
and every 12 hours for 48 hours thereafter. Dosing will be altered depending on
renal function. Patients who have been admitted to the hospital for an extended
period of time before their scheduled surgery will receive vancomycin.
· Patients are positioned supine, with the arms
at the side. A roll is not placed between or below the scapula to elevate the
chest. Defibrillator pads are placed on the patient’s back. One pad is placed
on the right posterior shoulder and the other on the left lower posterior
thorax. The chest is prepped with chlorhexidine. In addition, the inguinal
region and lower extremities are prepped for peripheral cannulation and for
vein harvesting, if required.
· A femoral platform is the access site of choice.
Left femoral artery and vein cannulation are preferred because most patients
undergo a cardiac catheterization via the right femoral artery. A CT angiogram
is not routinely obtained unless severe peripheral vascular disease is
suspected. Prior to cannulation, the patient is fully heparinized (300-400
units/kg). A 2- to 3-cm longitudinal skin incision is made above the inguinal
crease. This approach, along with limited dissection of the anterior aspect of
the vessels, decreases the incidence of seroma formation. Careful attention is
paid to assessing the quality of the artery. Presence of a posterior horseshoe
calcified plaque is not a contraindication for cannulation. Circumferential
calcification would negate cannulation. A 5-0 Prolene purse-string suture is
placed on the anterior aspect of each vessel. A modified Seldinger technique is
used for cannulation. A guidewire is advanced into the proximal descending
aorta and verified by TEE. Passage of the wire should be performed without
resistance. Thereafter, an arterial cannula is inserted into the artery. The
size of the cannula chosen will depend on the patient’s body surface area.
Occasionally, when passing the cannula over the guidewire, plaque may be felt
as the cannula is being advanced. The cannula is advanced as long as there is
no resistance. If any resistance is
encountered while advancing the cannula, an alternative access site should be
chosen. If any concerns exist, intraoperative angiography is performed, with
contrast injected through the cannula side port.
· When the femoral artery is small,
circumferential dissection of the vessel is performed, proximal and distal
control of the artery is obtained, and a direct arteriotomy is performed. The
guidewire is back-loaded in the arterial cannula, and the cannula is introduced
into the artery. The guidewire is advanced, and then the cannula is passed over
the guidewire (Fig. 10.1). If an alternative cannulation site is required, the
right axillary artery is the next access point of choice. In this case, a 2-cm
skin incision is performed 1 to 2 cm beneath the clavicle, medial to the
deltopectoral groove. Care is taken not to injure the surrounding nerves. The
vein is usually encountered first and is inferior to the artery. The artery is
commonly deep, and the pulse is palpated to guide the dissection. Once exposed,
the artery is encircled proximally and distally with vessel loops. A direct
arteriotomy is preferred for passage of the cannula. Intraoperative fluoroscopy
and angiography is always performed. Of note, a Seldinger technique can be
used, although the risk of damaging the vessel is greater. Central cannulation
can also be performed. In these cases, the pericardium is opened, and all the
pericardial retraction sutures are placed. Purse-string sutures are then placed
as distally as possible in the ascending aorta, and a Seldinger technique is
also used for cannulation.
· Once arterial cannulation is completed, femoral
venous cannulation is performed using a Seldinger technique. A 180-cm wire is
passed through the femoral vein and into the SVC under TEE guidance. A 0-degree
bicaval view is obtained for placement. Thereafter, a 25 F venous cannula is
advanced deep into the SVC. To obtain adequate venous drainage, the cannula
should be in the SVC and vacuum drainage applied. Vacuum assistance with 35 mm
Hg of negative suction is applied and increased to 65 mm Hg, if necessary. The
application of negative pressure causes an increase in the formation of gaseous
microemboli, although this has not been proven to be harmful. Studies have
demonstrated that surpassing 60 mm Hg of negative pressure does not increase
the incidence of neurologic events.22 Additional venous drainage is
required in case of right-sided distention or dislodgment of the venous cannula
into the right atrium. In these cases, a 4-0 purse-string suture is placed on
the SVC, and additional sump suction is inserted into the SVC.
· A 5- to 6-cm right minithoracotomy skin
incision is performed 1 cm lateral to the sternum at the level of the second or
third intercostal space (Fig. 10.2). Once the skin and subcutaneous tissues are
entered, limited dissection of the pectoralis muscle is performed. Exposure can
be challenging in young muscular patients. The intercostal muscle is then
entered. The right internal mammary artery and vein are identified and
transected between two clips. Care is taken to visualize each vessel clearly.
The lower costal cartilage is transected immediately lateral to the sternum.
Alternatively, the cartilage can be left intact and a rib spreader inserted to
gain additional exposure. This option can cause a residual chest wall defect,
which could lead to paradoxic
chest wall motion.
5.
Retraction
· A soft tissue retractor is inserted into the
pleural cavity and provides improved visualization. An intercostal rib spreader
is placed to provide additional exposure. A chest tube incision (utility port)
is then made several interspaces below the chest incision. Intravenous tubing
is placed through the utility port and passed out from the chest incision. This
tubing functions as a guide to pass cannulae and tubes and avoids creating
multiple false tracks through the chest wall. In addition, this will decrease
the potential of injuring the intercostal vessels (Fig. 10.3). At this point,
cardiopulmonary bypass is instituted, and the lungs are deflated. The
pericardium is opened over the aorta, and the incision extended down toward the
inferior vena cava. Care is taken not to open the pericardium superiorly past
the aortopericardial reflection. A pericardial stay suture is placed at the
level of the right superior pulmonary vein and tacked to the skin to aid
exposure. An additional pericardial retraction suture is placed at the level of
the SVC.
· The right atrium is retracted to the left, and
the pericardium adjacent to the right superior pulmonary vein is retracted to
the right. A purse-string suture is placed on the right superior pulmonary vein
(Fig. 10.4). A blunt-tipped left ventricular vent is inserted into the left
atrium or left ventricle. This is then exteriorized through the chest tube
incision (utility port).
· A purse-string suture is placed around the
lateral aspect of the right atrial appendage, and a retrograde cardioplegia
cannula is inserted into the coronary sinus. The end of the cardioplegia
cannula is bent at a 45-degree angle approximately 1 to 2 cm from its tip. This
will usually facilitate placement into the coronary sinus. If this maneuver is
not successful, the cannula is removed, and the tip is straightened and
reinserted. TEE guidance is used to assess entry into the coronary sinus. On
the midesophageal four-chamber view, at a probe depth of 30 to 35 cm with the
transducer angle between 0 and 20 degrees, the mitral and tricuspid valves are
visualized. After advancing the probe slightly, the coronary sinus in the
long-axis view can be appreciated just above the attachment of the tricuspid
valve septal leaflet to the interventricular septum.21 Once the
cannula is visualized in the coronary sinus, the stylet is removed, and the
cannula is advanced an additional 1 to 2 cm into the coronary sinus. It is
important to advance the cannula further once visualized in the coronary sinus
to avoid dislodgment.
· There are four points to confirm proper
placement of the retrograde cannula. The first is TEE visualization of the
cannula. The second is dark venous blood return from the cannula immediately
after proper placement. The third is ventricularization of the pressure
transduced from the cannula. The fourth is visualizing active blood return from
the coronary ostia after delivering cardioplegia. The cardioplegia catheter is
also exteriorized through the utility port.
· Alternatively, and preferentially, retrograde
cardioplegia cannulation is omitted, and the right atrial appendage is
retracted with a no. 2 silk loop. This loop is tunneled through the utility
port and pulls the right atrial appendage inferiorly to improve visualization
of the aortic root (Figs. 10.5 and 10.6).
· Additional pericardial sutures are placed. It
is important not to open the pericardium superiorly up to its insertion on the
aorta (Fig. 10.7). This will limit the ability of the pericardium to provide
the necessary retraction. Each maneuver will help lead to the next step in
facilitating additional exposure. In general, one should not make judgment on
the exposure or one’s ability to perform minimally invasive AVR until the
patient has been placed on bypass, and the heart and lungs are decompressed.
· A plane is then established beneath the aorta
and above the superior aspect of the right branch of the pulmonary artery for
placement of the aortic cross-clamp. The aorta is not dissected free from the
main pulmonary artery. A retractable, shafted, cygnet cross-clamp is then used
to cross-clamp the ascending aorta. A 6-inch, 14-G angiocatheter is
inserted into the aorta to deliver an induction dose of cardioplegia (Fig.
10.8). Thereafter, retrograde cardioplegia is delivered at 20-minute intervals
or sooner, if required. Additional doses of cardioplegia are given directly
into the coronary ostia if blood return is not visualized from both ostia
during delivery of retrograde cardioplegia or if there is a suspicion that the
coronary sinus cannula was not properly placed. However, note that this
aforementioned cardioplegia strategy is no longer used since the implementation
of extended-effect cardioplegia solutions.23 A modified del Nido
solution (four parts blood to one part crystalloid) containing 40 mEq potassium
is delivered either into the aortic root or directly into the coronary ostia. A
2-L induction dose will allow at least 90 to 100 minutes of safe protection. Of
note, no studies to date have confirmed the degree of protection that this
particular cardioplegia method provides in the adult cardiac surgical patient.
· The patient’s temperature is allowed to fall to
34°C (93.2°F). Active cooling is not performed unless the ascending aorta and hemiarch
are being replaced.13 In these cases, the SVC is encircled with a vessel loop,
a 4-0 Prolene purse-string suture is placed on the SVC, and a 24 F
wire-reinforced venous cannula is tunneled through the utility port and into
the SVC. This is used for retrograde cerebral perfusion during the period of
deep hypothermic circulatory arrest.
In this case, the patient is cooled to 20°C (68°F).
· An aortotomy is made at the level of the linear
fat pad located on the anterior aspect of the aorta with long-shafted
Metzenbaum scissors (Geister Medizintechnik, Tuttlingen, Germany). Care is
taken to stay at least 2 cm from the cross-clamp. A silk suture is then placed
on the upper aspect of the aortotomy to allow retraction of the aorta and
exposure of the aortic valve (Fig. 10.9). When the ventricular fat overlying
the RCA impedes visualization, another retraction suture can be placed on this
fat pad and tacked to the pericardium. CO2 is infused into the
operative field at a rate of 2 L/min throughout the entire procedure. Infusing
higher amounts of CO2 will raise the patient’s CO2 levels
while on cardiopulmonary bypass and will pose an arduous task for the
perfusionist to sweep off. Long-handled conventional Metzenbaum scissors or
long-shafted Mayo scissors are used to resect the aortic valve. If needed, a
rongeur is used to débride additional calcium. Because the assistant has
limited visibility to help suction the calcium, the rongeur is held in one hand
and the suction in the other simultaneously. After excision of the valve, the
root and left ventricle are irrigated to remove any residual debris.
Thereafter, 3-0 Prolene sutures are placed at the level of the commissures to
provide a so-called no-touch technique for exposure of the aortic valve. An
aortic valve exposure device (Aortic Cuff [small, medium, or large], Miami
Instruments, Miami, FL) is used to provide further exposure, if necessary (Fig.
10.10). The valve sutures are then placed on the aortic annulus in the
conventional manner (Fig. 10.11). The valve is sized, and the valve of choice
is selected. After the sutures are placed through the sewing cuff, the valve is
delivered onto the annulus. The valve usually requires manipulation to cross
the sinotubular junction. Once seated on the aortic annulus, each suture is
tied down carefully (Fig. 10.12). In certain cases, some of the sutures can be
tied manually, but one must avoid excessive traction on the suture to avoid
tearing the annulus, which will lead to a paravalvular leak. Each knot is
inspected prior to cutting the suture to ensure that an air knot does not
exist. If an air knot has occurred, the knot is teased and unraveled. This same
suture is then tied again. Once the valve is properly seated, the aortotomy is
closed in the desired fashion (Fig. 10.13).
· Prior to removal of the cross-clamp, the acute
margin of the right ventricle is retracted with a sponge stick, and the
muscular wall of the inferior aspect of the right ventricle is visualized. A
ventricular pacing wire is placed very superficially on the epicardium. It is
important to perform this maneuver with the heart empty prior to removing the
cross-clamp (Fig. 10.14). After the clamp is removed, it is virtually
impossible to place a ventricular lead on the inferior wall of the right
ventricle. An atrial pacing wire can be placed, although this is rarely
necessary. The patient is then placed in a Trendelenburg position, the heart is
filled, and air is removed from the aortic root. The cross-clamp is removed and
the angiocatheter, which was initially used to deliver antegrade cardioplegia,
is placed back into the aortic root for further removal of air. The heart is
filled and allowed to eject during this time. The left ventricular vent, which
was placed in the right superior
pulmonary vein, also aids air removal.
· Instruments are not placed directly through the
chest incision to manipulate the heart. Once there is TEE confirmation of adequate air removal, two purse-string
sutures are placed to seal the antegrade cardioplegia delivery site. The
patient is subsequently weaned from cardiopulmonary bypass. After half of the
protamine is administered, the femoral venous cannula is removed, and the
purse-string suture is tied. After complete administration of the protamine,
the arterial cannula is removed, and the purse-sting suture is tied as well.
· A Blake chest drain is placed over the main
pulmonary artery and advanced into the posterior pericardial well (Fig. 10.15).
An additional Blake drain is placed posteriorly and laterally in the pleural
space. The Blake drains, pacing wire, and pain management catheters are all
exteriorized through the utility port.
· Closure of the chest wall needs to be
meticulously performed to avoid paradoxic chest wall motion and maintain chest
wall stability. Once hemostasis is obtained, one additional clip is placed on
either side of the transected right internal mammary artery and vein. Care is
taken not to place an excessive number of clips because of the potential of
tearing the vessels. The ON-Q Pain Relief System (Halyard Health, Alpharetta,
GA) has two catheters, which are placed freely in the pleural space and
connected to a dispenser that delivers 0.25% bupivacaine (Marcaine) at 4 mL/hr
for 3 days. Alternatively, one catheter can be placed freely in the pleural
space and the other extrapleurally, adjacent to the entered intercostal space.
A 1-0 Vicryl suture is placed through the sternum and then through the
transected cartilage. This suture is tied, and then the same suture is placed
in a figure-of-eight fashion from the transected rib to the upper rib.
Thereafter, 0 Vicryl sutures are used to approximate the intercostal muscle to
the periosteum of the rib. The sutures are continued laterally, incorporating
as much of the intercostal muscle as possible. The last suture is locked, and
the second layer of the closure approximates the fat pad that lies underneath
the pectoralis muscle. This suture is continued medially and locked again. The
pectoralis muscle is then approximated in a two-layer fashion. The skin is cosmetically closed in
routine fashion11 (Fig. 10.16).
Figure 10.15 Blake chest tubes placed in pericardial space
and pleural space.
Figure 10.16 Skin closure.
|
· On arrival to the intensive care unit, a rapid ventilator
weaning protocol is instituted, depending on the patient’s condition. The
amount of bleeding from the chest tubes is usually insignificant. Chest tube
drainage of more than 75 to 100 mL/hr is not common. If this occurs,
reexploration should be considered unless a coagulopathy is suspected or the
patient is on clopidogrel (Plavix). It is common for patients to have an air
leak, which is caused by having two Blake drains adjacent to each other and
exteriorized through one chest tube incision. The drains, pacing wire, and pain
management catheters (ON-Q) are usually removed on the third day. The drains
are usually not removed earlier due to persistent serous drainage. Patients who
do not have coronary artery disease will be placed on nonsteroidal antiinflammatory
drugs for 3 weeks.
· A minithoracotomy, minimally invasive aortic
valve surgery, is a true sternal-sparing minimally invasive procedure. Benefits
include diminished ventilator time, reduced intensive care unit and hospital
lengths of stay.1-5,19,24 In addition, patients can return to their
normal lifestyles sooner because of less surgical trauma and improved chest
wall stability, which allows them to be more functional sooner compared to
standard sternotomy patients. Other benefits include less transfusions and
analgesics and improved cosmesis.19,25 A decrease in the composite complication
rate in higher-risk patients (e.g., obese patients, patients > 75 years,
patients with COPD or low ejection fraction),1,2,4 as well as a
decrease in surgical mortality, have been documented.12,24 A
minimally invasive valve program is an essential addition to any cardiac
surgical service and offers patients additional options for the treatment of
aortic valve disorders. In addition, it provides cardiac surgeons with
alternative techniques to address concomitant valvular and aortic pathologies.
Considering the rapid development of transcatheter aortic valve technology with
direct access implants as a treatment option, as well as the future availability
of surgical sutureless aortic valves, the minithoracotomy approach is a useful
technique in our armamentarium. Finally, the ability to perform less invasive
surgical techniques such as this
one is essential for surgeons who wish to remain relevant.
References
1.
Lamelas J, Sarria A, Santana O, Pineda AM, et al. Outcomes of minimally
invasive valve surgery versus median sternotomy in patients 75 years or
greater. Ann Thorac Surg. 2011;91:79–84.
2.
Santana O, Reyna J, Grana R, et al. Outcomes of minimally invasive valve
surgery versus standard sternotomy in obese patients undergoing isolated valve
surgery. Ann Thorac Surg. 2011;91:406–410.
3.
Schmitto JD, Mokashi SA, Cohn LH. Minimally-invasive valve surgery. J
Am Coll Cardiol. 2010;56:455–462.
4.
Santana O, Reyna J, Benjo AM, et al. Outcomes of minimally invasive
valve surgery in patients with chronic obstructive pulmonary disease. Eur J
Cardiothorac Surg. 2012;42:648–652.
5.
Glauber M, Miceli A, Bevilacqua S, Farneti PA. Minimally invasive aortic
valve replacement via right anterior minithoracotomy: early outcomes and
midterm follow-up. J Thorac Cardiovasc Surg. 2011;142:1577–1579.
6.
Cosgrove DM 3rd, Sabik JF. Minimally invasive approach for aortic valve
operations. Ann Thorac Surg. 1996;62:596–597.
7.
Johnston DR, Atik FA, Rajeswaran J, et al. Outcomes of less invasive
J-incision approach to aortic valve surgery. J Thorac Cardiovasc Surg.
2012;144:852–858.
8.
Tabata M, Umakanthan R, Cohn LH, et al. Early and late outcomes of 1000
minimally invasive aortic valve operations. Eur J Cardiothorac Surg.
2008;33:537–541.
9.
Fenton JR, Doty JR. Minimally invasive aortic valve replacement surgery
through lower half sternotomy. J Thorac Dis. 2013;5:S658–S661.
10.
Burdett CL, Lage IB, Goodwin AT, et al. Manubrium-limited sternotomy
decreases blood loss after aortic valve replacement surgery. Interact Cardiovasc Thorac Surg. 2014;19:605–610.
11.
Santana O, Reyna J, Benjo AM, Lamas GA, Lamelas J. Outcomes of minimally
invasive valve surgery in patients with chronic obstructive pulmonary disease. Eur
J Cardiothoracic Surg. 2012;42:648–652.
12.
Merk DR, Lehmann S, Holzhey DM, et al. Minimal invasive aortic valve
replacement surgery is associated with improved survival: a propensity-matched
comparison. Eur J Cardiothorac Surg. 2015;47:11–17.
13.
LaPietra A, Santana O, Pineda AM, et al. Outcomes of aortic valve and
concomitant ascending aorta replacement performed via a minimally invasive
right thoracotomy approach. Innovations (Phila). 2014;9:339–342.
14.
Pineda AM, Santana O, Lamas GA, Lamelas J. Is a minimally invasive
approach for re-operative aortic valve replacement superior to a standard full
sternotomy? Interact Cardiovasc Thorac Surg. 2012;15248–15252.
15.
Pineda AM, Santana O, Reyna J, et al. Outcomes of reoperative aortic
valve replacement via a right mini-thoracotomy versus a median sterntomy. J
Heart Valve Dis. 2013;22:50–55.
16.
Santana O, Pineda AM, Cortes-Bergoderi M, et al. Hybrid approach of
percutaneous coronary intervention followed by minimally invasive valve
operations. Ann Thorac Surg. 2014;97:2049–2055.
17.
Santana O, Funk M, Zamora C, et al. Staged percutaneous coronary
intervention and minimally invasive valve surgery: results of a hybrid approach
to concomitant coronary and valvular disease. J Thorac Cardiovasc Surg.
2012;144:634–639.
18.
LaPietra A, Santana O, Mihos CG, et al. Incidence of cerebrovascular
accidents in patients undergoing minimally invasive valve surgery. J Thorac
Cardiovasc Surg. 2014;148:156–160.
19.
Glauber M, Gilmanov D, Farneti PA, et al. Right anterior minithoracotomy
for aortic valve replacement: 10-year experience of a single center. J
Thorac Cardiovasc Surg. 2015;150:548–556.
20.
Madershahian N, Wippermann J, Sindhu D, Wahlers T. Unilateral
re-expansion pulmonary edema: a rare complication following one-lung
ventilation for minimal invasive mitral valve reconstruction. J Card Surg.
2009;24:693–694.
21.
Hahn RT, Abraham T, Adams MS, et al. Guidelines for performing a
comprehensive transesophageal echocardiographic examination: recommendations
from the American Society of Echocardiography and the Society of Cardiovascular
Anesthesiologists. J Am Soc Echocardiogr. 2013;26:921–964.
22.
Lou S, Ji B, Liu J, et al. Generation, detection and prevention of
gaseous microemboli during cardiopulmonary bypass procedure. Int J Artif
Organs. 2011;34:1039–1051.
23.
Matte GS, del Nido PJ. History and use of del Nido cardioplegia solution
at Boston Children’s Hospital. J Extra Corpor Technol. 2012;44:98–103.
24.
Glower DD, Desai BS, Hughes GC, et al. Aortic valve replacement via
right minithoracotomy versus median sternotomy: a propensity score analysis. Innovations
(Phila). 2014;9:75–81.
25.
Brown ML, McKellar SH, Sundt TM, Schaff HV. Ministernotomy versus
conventional sternotomy for aortic valve replacement: a systematic review and meta-analysis. J Thorac Cardiovasc Surg.
2009;137:670–679.