Use of Right Ventricular Support with a Centrifugal Pump in Post

Document technical information

Format pdf
Size 504.5 kB
First found May 22, 2018

Document content analysis

Category Also themed
Language
English
Type
not defined
Concepts
no text concepts found

Persons

Organizations

Places

Transcript

The Journal of Tehran University Heart Center
Case Report
Use of Right Ventricular Support with a Centrifugal Pump
in Post-Valve Surgery Right Ventricular Failure: A Case
Series
Abdol Rasoul Moulodi, MD, Gholam Reza Sheibat Zadeh, MD, Feridoun
Sabzi, MD*
Imam Ali Cardiovascular Center, Kermanshah University of Medical Sciences, Kermanshah, Iran.
Received 04 October 2012; Accepted 13 February 2013
Abstract
The optimal treatment method for right ventricular failure after valve surgery complicated by a low cardiac output has
not been determined, although several case reports have been published on patients with ventricular failure and arrhythmia
who were bridged to cardiac transplantation using biventricular or left ventricular assist devices. This case series illustrates
successful circulatory support of 4 patients with prolonged low cardiac outputs and right ventricular failure and arrhythmias
after valvular heart surgery with or without severe pulmonary hypertension. In-hospital death occurred in one patient and 3
patients were discharged from the hospital with good general condition. At two years' follow-up, 2 patients were in functional
class one but another patient underwent laparotomy for multiple splenic abscesses and died from multiple organ failure.
J Teh Univ Heart Ctr 2014;9(1):38-42
This paper should be cited as: Moulodi A. R, Sheibat Zadeh G. R, Sabzi F. The Use of Right Ventricular Support with a Centrifugal
Pump in Post Valve Surgery Right Ventricular Failure: A Case series. J Teh Univ Heart Ctr 2014;9(1):38-42.
Keywords: Cardiac surgical procedures • Ventricular dysfunction, Left • Heart-assist devices
Introduction
P
ost-cardiotomy right ventricular (RV) failure can
be caused by prolonged aortic cross-clamp time and
cardioplegic arrest, inadequate myocardial protection, and
right coronary artery obstruction due to coronary vasospasm,
air embolization, and thrombus. In transplantation recipients,
donor organ ischemia and preexistent or perioperative
pulmonary hypertension mainly contribute to the
development of acute refractory RV failure.1, 2
RV failure is one of the serious complications of open
heart surgery, and if it does not respond to maximum
inotropic agents and the intra-aortic balloon pump (IABP),
surgeons tend to use the assist device. If echocardiography
fails to reveal a surgically correctable cause for cardiogenic
shock, most surgeons use homodynamic data to consider
the need for mechanical assistance. These criteria include
a cardiac index less than 2.2 L/min/m2, systolic pressure
lower than 90 mmHg, central venous pressure (CVP) higher
than 20 mmHg, and concomitant use of a high dose of at
least two inotropic agents.3-5 This situation may be clinically
associated with arrhythmia, pulmonary edema, and oliguria.
In such circumstances, the use of an IABP may be considered
as the first step in the post-cardiotomy shock setting. Without
mechanical support, mortality is greater than 50%. In this
setting, some believe that early implantation of an assist
*
Corresponding Author: Feridoun Sabzi, Professor of Cardiac Surgery, Kermanshah University of Medical Sciences, Imam Ali Hospital, Shahid
Beheshti Street, Kermanshah, Iran. Tel: +98 831 8360042. Fax: +98 831 8362022. E-mail: [email protected]
38
J Teh Univ Heart Ctr 9(1)
January 12, 2014
http://jthc.tums.ac.ir
Use of Right Ventricular Support with a Centrifugal Pump in Post-Valve Surgery ...
device capable of supporting high flow and allowing the
heart to rest may improve the outcome and allow for the
recovery of stunned myocardium.6, 7
Since their invention in 1985, there have been more than
1000 cases of implanted ventricular assist devices for postcardiotomy shock. Most of the recipients had ischemic heart
disease; however, there were also rare cases of valvular heart
disease with post-cardiotomy shock treated with bio-pump
assistance. The average duration of support for these devices
was approximately 3 days, 45% of the reported patients
were weaned from circulatory assistance, and 25% of all
the patients survived to discharge. These numbers remain
consistent with previously reported statistics.8, 9 The results
of the Biomedicus centrifugal pump, employed in postmyocardial infarction cardiogenic shock, remain limited.
In the literature, of the 96 patients reported by 10 referral
hospitals, 26% were weaned from support and only 11.5%
survived to discharge.10-12
In our hospital, we utilized the bio-pump for first time
in post-cardiotomy right heart failure resulting from mitral
valve surgery. These patients did not respond to maximum
inotropic agent and IABP. The mean ejection fraction of
our cases was 42% ± 6%, and the mean pulmonary artery
pressure was 50 ± 8 mmHg. Additionally, the mean end
systolic volume in 2 cases was 76 ± 6 ml. For these patients,
with continued cardiogenic shock despite maximum
inotropic drug and IABP use, the bio-pump assist device
was advocated. The cause of cardiogenic shock was postcardiotomy severe RV failure. RV failure occurred after mitral
valve replacement (one case of pure mitral regurgitation and
three cases of mitral regurgitation and mitral stenosis). The
mean pressure with the IABP and assist device was 63 ± 6
mmHg versus 20 ± 30 mmHg with the IABP off. During the
first postoperative hour, the bio-pump flow ranged from 3.6
to 2.5 L/ml. The duration of the IABP use ranged from 5 to 10
days, and the duration of the bio-pump use ranged from 24 to
36 hours. All the 4 patients were successfully weaned from
the assist device; nevertheless, one of these patients died
after successful weaning from the RV assist device (RVAD)
from cerebrovascular accident. One patient developed
hemiparesis, which completely cleared after 3 months. All
the survived patients developed pulmonary edema and adult
respiratory distress syndrome, which were managed via
tracheostomy and respiratory physiotherapy. One patient
was readmitted due to sepsis and a splenic abscess in the
second postoperative month. One patient was treated for
lobar pneumonia and another for purulent tracheitis.
A combined usage of the IABP and the bio-pump appears
to be a better therapy than either one individually.
Technique
TEHRAN HEART CENTER
of valveless rotator cones that create a rotatory motion in
the incoming blood by viscous drag and constrained vortex
principles. In this manner, the cones generate pressure and
flow. These elements are contained in a polycarbonate coneshaped container with an inlet and outlet. These pumps are
afterload-dependent unlike the roller type pump. They can
be used to bypass both the right and left ventricle and are
easy to operate. They are driven by a magnetic impeller
that has no direct contact with the blood within. A separate
console allows the operator to control the revolutions and set
alarms. Conventional bypass cannulae are used together with
bypass tubing to connect the ventricle to the pump outside
the body. The right atrial cannula (usually 32F or 34F venous
cannula) can be placed through the right atrial appendage.
Typically, purse string sutures with Teflon pledgets are
placed in the base of the appendage, and passed through
rubber tourniquets. The right atrial pressure is raised by
restricting the venous return, the atrium is opened, and the
cannula is inserted. After the right atrial cannula is secured, it
is connected to the inflow line of the bio-pump. All air must
be excluded from the connection and tubing at this time.
A pulmonary artery cannula (22F-angle aortic arch
cannula) is inserted into the pulmonary artery distal to the
pulmonic valve and secured with purse string sutures. The
cannulae are brought out through the inferior angle of the
incision. The skin is approximated, whereas the sternum is
left open. The perfusion lines are securely sutured to the skin
and covered with several towels and a large adhesive plastic
drape. Weaning is usually not attempted during the first 24
hours of assist support. When the patient’s hemodynamic
is stable and cardiac improvement is suspected, a weaning
assessment can be completed within a few minutes or less.
The following parameters must be assessed and recorded by
the perfusionist: the pump flow must never be decreased to
less than 1 L/min. At 1 L/min, the activated clotting time
must be greater than 200 seconds, and the duration of time
at this flow must not exceed 2 minutes. If the pump flow is
to be kept at 1 L/min for longer than 2 minutes, the activated
clotting time must be extended to 200 seconds.
Anticoagulation
Coagulopathy
Regimen
and
After cardiopulmonary bypass (CPB), heparin should
be reversed with protamine. After being returned to the
Intensive Care Unit (ICU), the patient is not anticoagulated
until clotting measures have normalized, after which the
administration of heparin is commenced to maintain the
activated clotting time above 150 seconds. The perfusionist
on duty is responsible for performing activated clotting time
monitoring and determining necessary heparin doses.6-11
The Biomedicus Pump used in the present study consists
The Journal of Tehran University Heart Center 39
J Teh Univ Heart Ctr 9(1)
January 12, 2014
http://jthc.tums.ac.ir
The Journal of Tehran University Heart Center
Abdol Rasoul Moulodi et al.
Case # One
The patient was a 51-year-old woman who was referred
from rural regions of Kurdistan with severe mitral stenosis
associated with a left arterial clot and severe pulmonary
hypertension.
She underwent mitral valve replacement and removal of
the clot. After having been weaned from CPB, the patient
developed RV failure. CPB was, therefore, resumed and
followed by a high dose of inotropic drugs and the IABP,
which failed to yield complete response, and repeated
ventricular tachycardia and fibrillation complicated the
condition. Consequently, RV support through the insertion
of a centrifugal pump was considered, and the patient was
successfully weaned from CPB on the second postoperative
day. The RV support was discontinued on the third
postoperative day, and the IABP was removed without
marked homodynamic changes on the seventh postoperative
day.
Case # Two
The patient was a 51-year-old woman who was referred to
our center for the management of mitral stenosis associated
with a large left atrial clot.
She underwent the operation via CPB and moderate
hypothermia. Antegrade cold cardioplegia was instituted
to arrest and protect the heart and systemic hypothermia to
28 °C. The left atrium was approached via the conventional
method. The mitral valve was heavily calcified, and the
subvalvular structures were fused. The anterior mitral leaflet
was resected, while the posterior leaflet and its subvalvular
complex were left intact. A 29-mm Carbomedix mitral
prosthesis was implanted using separate pledged sutures.
The patient was successfully weaned with a high dose of
adrenalin and Dobutamine 60 minutes after CPB institution.
The patient developed a low cardiac output in the immediate
postoperative period. As the patient’s condition worsened
progressively, the IABP was inserted. The homodynamic
of the patient recovered transiently for a short time, but it
was worsened subsequently by fibrillation and ventricular
tachycardia, both of which were managed by cardioversion
and intravenous Amiodarone administration. The systolic
blood pressure was 60-70 mmHg. Episodes of paroxysmal
ventricular tachycardia and occasional ventricular fibrillation
reoccurred and became more frequent during the ensuing
hours. High-dose inotrope support, including adrenalin (100
µ/kg/min), Dobutamine (40 µ/kg), and Milrinone (0.5 µ/kg),
was commenced.
Informed consent was obtained to use a Biomedicus
bio-pump as an RVAD so as to support the patient’s poor
homodynamic condition. Four hours after the insertion
of the RVAD, the patient’s homodynamic recovered. The
RVAD’s output dung this time ranged from 2.3 to 3.2 L/
min, and the systolic blood pressure ranged from 70 to 100
mmHg. No episode of paroxysmal ventricular tachycardia
and fibrillation was observed. Right atrial pressure before
the insertion of the RVAD was 35 mmHg, and it dropped
to 15 mmHg on the second postoperative day. Postoperative
creatinine phosphokinase myocardial band (CPK-MB)
value was normal, which ruled out RV infarction due to
poor protection or myocardial infarction. Hepatic enzymes
and direct and indirect bilirubin values were elevated, and
urine output was maintained with a high dose of Lasix. On
the third postoperative day, the pump flow was gradually
decreased to 500/ml/minute for 6 hours without major
hemodynamic changes. Improved left ventricular contraction
and remarkably improved RV contractility were detected in
transesophageal echocardiography (TEE). Thereafter, the
device was minimized to slow flow, and the patient was
subsequently weaned from the device after 72 hours. The
sternum was left open after subsequent device removal with
skin closure until the fifth postoperative day. All the inotropic
drugs were progressively reduced and discontinued. During
this time period, hemolysis, jaundice and bleeding occurred;
they were all treated with large amounts of packed red cells
and other blood products. The IABP was discontinued on the
seventh postoperative day.
The patient developed adult respiratory distress syndrome,
which was managed via tracheostomy and intense respiratory
care. She was weaned from the ventilator on the thirteenth
postoperative day, and her renal and hepatic function as
well as neurologic status had completely recovered by the
sixteenth postoperative day.
Case # Three
The patient was a 37-year-old woman with a past medical
history of mitral valve replacement. She was referred to
our hospital for the management of prosthetic mitral valve
malfunction.
The operation was conducted via CPB with moderate
hypothermia and antegrade and retrograde cardioplegia
injections. The left atrium was opened via the conventional
method. The prosthetic mitral valve had an old pannus tissue
with recent thrombosis in its ring. The prosthetic valve
was cleaned, and the left atrium was irrigated with copious
amounts of normal saline. The patient was successfully
weaned from CPB with high-dose inotropic drugs, but
she developed a low cardiac output in the immediate
postoperative period. As the patient’s condition worsened
and did not respond to balloon pump and high-dose inotropic
drug support, we decided to use a bio-pump as an RVAD in
order to support the patient’s poor hemodynamic condition.
After the application of a Biomedicus centrifugal pump as an
RVAD, the patient was transferred to the ICU with the IABP,
40
J Teh Univ Heart Ctr 9(1)
January 12, 2014
http://jthc.tums.ac.ir
Use of Right Ventricular Support with a Centrifugal Pump in Post-Valve Surgery ...
bio-pump, and high-dose inotropic drug support.
Three hours after the insertion of the bio-pump, the RV
tachycardia was abolished. During this time period, the biopump’s output was reduced from 4 L/min to 3 L/min. The
mean and systolic blood pressures were 70 and 90 mmHg,
respectively. The patient’s high CVP (37 mmHg) in the first
hour following the insertion of the bio-pump reduced to 15
mmHg on the second day.
After 30 hours of bio-pump use, we reduced the bio-pump’s
flow to a minimum of 500 ml/min and reduced the patient’s
adrenaline and Dobutamine requirement to the minimum
dose. During this time period, cardiac enzymes, including
CPK-MB, were normal, but the patient developed severe
jaundice and bleeding, which were treated with 30 unites
of packed red cells and blood products. Postoperative acute
respiratory distress syndrome was managed via tracheostomy
and respiratory care. On the seventh postoperative day, the
patient was completely weaned from ventilation.
Case # Four
The patient was a 33-year-old woman with a past medical
history of open mitral commissurotomy. She was referred to
our center for the management of combined severe mitral
regurgitation and stenosis.
The operation was conducted via CPB and hypothermia (28
°C), and cardiac protection was achieved with an antegrade
cardioplegia infusion. The left atrium was approached via
the transseptal method. Following the resection of the
heavily calcified and tethered mitral valve apparatus, the
mitral valve was replaced with a Carbomedics valve (29
mm) using continuous sutures of 2/0 viline and the tricuspid
valve was repaired via the Devega method. The patient was
successfully weaned from CPB with high-dose inotropic
drug and IABP support. During the following 6 hours, the
RV function did not improve and the inotropic support could
not be reduced.
At this stage, the patient developed signs of end-organ
dysfunction, elevated transaminase levels, and a decreased
urine output. We, therefore, implanted a Biomedicus biopump as an RVAD. Eight hours after the insertion of the
RVAD, the patient’s hemodynamic recovered, the RVAD’s
flow (4 lit/min) dropped to 3 lit/min, and the right atrial
pressure reduced from 40 mmHg to 15 mmHg. Cardiac
enzymes were normal, and the patient was weaned from the
respirator on the seventh post-RVAD insertion day.
The patient’s renal failure necessitated continuous
peritoneal dialysis for 2 days. Antimicrobial therapy
with intravenous Ceftazidime and Gentamicin was also
commenced. In the following days, the signs of end-organ
dysfunction improved, as was indicated by an increase
in the urine output, resolution of jaundice, and reduction
in hepatic enzymes levels. Two days after the patient had
TEHRAN HEART CENTER
been weaned from the mechanical respirator, the IABP was
removed. Unfortunately, however, the patient died due to
fatal intracerebral hemorrhage. The hemodynamic values of
the 4 patients are depicted in Table 1.
Table 1. Hemodynamic values in four patients weaned from cardiopulmonary
bypass with Biomedicus bio-pump*
Value
Before BBI
During BBI
After BBI
SAP (mmHg)
63.8±0.83
63.3±1.1
77.3±1.5
PAP (mmHg)
45.1±1.6
47.6±1.2
21.8±1.5
RAP (mmHg)
30.7±1.2
33.5±2.4
16.5±1.2
*
Data are presented as mean±SD
SAP, Systolic arterial pressure; PAP, Pulmonary arterial pressure (systolic);
BBI, Biomedicus bio-pump insertion; RAP, Right atrial pressure
Discussion
The optimal management for patients with profound
right cardiac failure and malignant ventricular arrhythmias
after valve replacement associated with severe pulmonary
hypertension has yet to be clearly delineated. The available
options include the biventricular assist device, the left
ventricular assist device, and the RVAD. Since its invention
in 1985, the ventricular assist device has been implanted
in more than 1000 patients for the management of postcardiotomy cardiogenic shock. Most of the recipients had
ischemic heart disease, and a few cases received the bio-pump
as an RVAD for the treatment of post-valvular cardiotomy
shock. The average duration of support for these devices is
approximately 3 days. Forty-five per cent of the reported
patients were weaned from circulatory assistance, and 25%
of all the patients survived to discharge. These numbers
remain consistent with previously reported statistics.
The results of the bio-pump as an RVAD for the treatment
of post-myocardial infarction cardiogenic shock remain
limited. In the literature, of the 96 patients reported by 10
referral hospitals, 26% were weaned from support and only
11.5% survived to discharge. In our hospital, we used the biopump for the first time for the treatment of post-cardiotomy
right heart failure in patients undergoing valvular surgery.
None of our patients responded to maximum inotropic agents
and IABP support. The mean ejection fraction in our cases
was 35% ± 5%, and the mean pulmonary artery pressure
was 60 ± 8 mmHg. The end systolic volume in 2 cases
was 76 ml. We used the bio-pump in 4 patients (3 women
and one man, age ranging from 33 to 60 years old) with
refractory and cardiogenic shock not responsive to inotropic
drug use and the IABP insertion. The cause of cardiogenic
shock was myocardial infarction in one case (severe mitral
valve calcification) and stunning or inadequate myocardial
protection in the other 3 patients (one case of pure mitral
regurgitation and 2 cases of combined mitral regurgitation
and mitral stenosis). The mean arterial pressure with the
IABP and the assist device was 63 ± 6 mmHg versus 20-30
The Journal of Tehran University Heart Center 41
J Teh Univ Heart Ctr 9(1)
January 12, 2014
http://jthc.tums.ac.ir
The Journal of Tehran University Heart Center
Abdol Rasoul Moulodi et al.
mmHg with the IABP off. In the first hours following the
insertion of the bio-pump, the flow ranged from 3.6 to 2.5 lit/
ml. The duration of the IABP use ranged from 5 to 10 days.
The artificial heart is not available at our institution; as a
result, we employed the Biomedicus bio-pump as an RVAD
in our 4 patients for the following reasons:12-14 1. severe
pulmonary hypertension (110 mmHg); 2. high right atrial
pressure (35 mmHg); 3. low left atrial pressure; 4. poor
homodynamic condition (systemic hypotension); 5. RV
distension; 6. good left ventricular function or vigorous left
ventricular contraction; and 7. refractory arrhythmia.
We also drew upon the following echocardiographic
criteria for the definition of the RV dysfunction after open
heart surgery: tricuspid valve regurgitation; RV end diastolic
diameter (RVEDD) > 40 mm; RV ejection fraction (RVEF)
< 30%; and right atrial dimension > 50 mm.
Previous experience and published information indicate
that the RVAD is useful in RV infarction following open
heart surgery.6-14 Be that as it may, there is no published
information about ventricular arrhythmia and right heart
failure secondary to severe pulmonary hypertension treated
with the RVAD. We assumed that right heart failure and
ventricular arrhythmia were an acute event that would be
resolved by reducing pulmonary hypertension as indicated by
postoperative echocardiography. Our patients had ventricular
arrhythmia that at times repeated, and they experienced
numerous cardioversions and defibrillation with no adverse
sequel. The placement of the RVAD in a second operation was
considered because we believed the arrhythmias and poor
homodynamic condition would resolve with time in these
patients. Circulatory support using only a centrifugal pump
as an RVAD and the IABP was feasible despite refractory and
recurrent ventricular arrhythmias and low output syndrome.
Although RV failure due to severe pulmonary hypertension
is a serous intraoperative complication, favorable results
were obtained by combined therapy with the IABP and the
RV support using a centrifugal pump in our patients.15-17
Conclusion
References
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
Isolated RV failure is diagnosed on the basis of low left
atrial and systemic arterial pressures and elevated right atrial
pressure in addition to vigorous left ventricular contractions,
right ventricular distention, and severe RV dysfunction as
detected by transesophageal echocardiography. Standard
therapy for severe right heart failure consists of inotropic
drug support, volume unloading, and application of
pulmonary vasodilators (prostaglandin and nitric oxide).
When pharmacological agents are unable to improve the
RV contraction, surgeons must rely on mechanical means to
restore the blood flow to the pulmonary circulation and left
ventricle.
14.
15.
16.
17.
Farrar DJ, Hill JD, Gray LA, Jr, Galbraith TA, Chow E, Hershon
JJ. Successful biventricular circulatory support as a bridge to
cardiac transplantation during prolonged ventricular fibrillation
and asystole. Circulation 1989;80:III147-151.
Moroney DA, Swartz MT, Reedy JE, Lohmann DP, McBride
LR, Pennington DG. Importance of ventricular arrhythmias in
recovery patients with ventricular assist devices. ASAIO Trans
1991;37:M516-517.
Arai H, Swartz MT, Pennington DG, Moriyama Y, Miller L,
Peigh P, McBride L. Importance of ventricular arrhythmias in
bridge patients with ventricular assist devices. ASAIO Trans
1991;37:M427-428.
Pennington DG, Reedy JE, Swartz MT, McBride LR, Seacord LM,
Naunheim KS, Miller LW. Univentricular versus biventricular
assist device support. J Heart Lung Transplant 1991;10:258-263.
Geannopoulos CJ, Wilber DJ, Olshansky B. Control of refractory
ventricular tachycardia with biventricular assist devices. Pacing
Clin Electrophysiol 1991;14:1432-1434.
Weiss JN, Nademanee K, Stevenson WG, Singh B. Ventricular
arrhythmias in ischemic heart disease. Ann Intern Med
1991;114:784-797.
Miyamoto M, Matsumoto N, Okada H, Nishida K, Suzuki K,
Noda H, Kato T, Tsuboi H, Mori F, Esato K. Centrifugal pump as
right ventricular assist pump in the treatment of right ventricular
failure following resection of left atrial myxoma. Kyobu Geka
1991;44:168-171.
Tsunemi K, Hasegawa S, Asada K, Sasaki S. The use of right
ventricular support with a centrifugal pump in a case with right
ventricular failure due to intraoperative right ventricular infarction.
Kyobu Geka 2003;56:459-463.
Fukuchi T, Ohkawa Y, Koike S, Kubo K, Murase K. A case of
acute right ventricular infarction and life-saving right ventricular
assistance following emergency coronary revascularization and
resection of a left ventricular aneurysm--discussion of indication
and proper assist flow volume. Nihon Kyobu Geka Gakkai Zasshi
1992;40:1767-1772.
Moazami N, Moon MR, Pasque MK, Lawton JS, Bailey MS,
Damiano RJ, Jr. Strategies for temporary mechanical support:
contemporary experience with pulsatile and non-pulsatile support
systems. Heart Surg Forum 2005;8:E216-220.
Kitamura M, Aomi S, Hachida M, Nishida H, Endo M, Koyanagi
H. Current strategy of temporary circulatory support for severe
cardiac failure after operation. Ann Thorac Surg 1999;68:662-665.
Chen JM, Levin HR, Rose EA, Addonizio LJ, Landry DW, Sistino
JJ, Michler RE, Oz MC. Experience with right ventricular assist
devices for perioperative right-sided circulatory failure. Ann
Thorac Surg 1996;61:305-310.
Samuels LE, Holmes EC, Thomas MP, Entwistle JC, 3rd, Morris
RJ, Narula J, Wechsler AS. Management of acute cardiac failure
with mechanical assist: experience with the ABIOMED BVS 5000.
Ann Thorac Surg 2001;71:S67-72.
Noon GP, Lafuente JA, Irwin S. Acute and temporary ventricular
support with BioMedicus centrifugal pump. Ann Thorac Surg
1999;68:650-654.
Moazami N, Hill L. Right ventricular dysfunction in patients
with acute inferior MI: role of RV mechanical support. Thorac
Cardiovasc Surg 2003;51:290-292.
Schmid C, Radovancevic B. When should we consider right
ventricular support? Thorac Cardiovasc Surg 2002;50:204-207.
Magovern GJ, Jr, Simpson KA. Extracorporeal membrane
oxygenation for adult cardiac support: the Allegheny experience.
Ann Thorac Surg 1999;68:655-661.
42
J Teh Univ Heart Ctr 9(1)
January 12, 2014
http://jthc.tums.ac.ir
×

Report this document