Case Report Hemolysis and Pulmonary Insufficiency

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Hindawi Publishing Corporation
Case Reports in Transplantation
Volume 2012, Article ID 376384, 3 pages
doi:10.1155/2012/376384
Case Report
Hemolysis and Pulmonary Insufficiency following Right
Ventricular Assist Device Implantation
Sarah A. Schubert, Behzad Soleimani, and Walter E. Pae
Department of Cardiothoracic Surgery, Penn State Hershey Heart and Vascular Institute, 500 University Drive,
Hershey, PA 17033, USA
Correspondence should be addressed to Sarah A. Schubert, [email protected]
Received 24 April 2012; Accepted 23 August 2012
Academic Editors: A. Beiras-Fernandez and D. Conti
Copyright © 2012 Sarah A. Schubert et al. This is an open access article distributed under the Creative Commons Attribution
License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly
cited.
We report a case of severe hemolysis and pulmonary valve insufficiency (PI) following right ventricular support using a
paracorporeal pneumatic pump (Abiomed, Danvers, MA, USA). We speculate that the high velocity jet of blood emanating from
the outflow cannula caused turbulence above the pulmonary valve, leading to PI and hemolysis. Despite the growing number of
implanted ventricular assist devices, we could find no report in the literature describing pulmonary valve insufficiency secondary
to right ventricular assist device (RVAD) placement. Fortunately, in this case, right ventricular function recovered sufficiently after
seven days of support, allowing explantation of the device and resolution of PI and hemolysis.
1. Introduction
Although cardiac transplantation remains the gold standard
for the treatment of end-stage heart failure, the demand
for transplantable hearts exceeds the supply. Fortunately,
ventricular assist devices have emerged as a viable bridging
therapy until a donor heart is obtained. Despite their uncomplicated design and relatively straightforward placement in
the chest, care must be taken during pump and cannulae
positioning, and patients must be monitored closely following surgery. Here we present a case of hemolysis and PI
following right ventricular support with a biventricular assist
device.
A 21-year-old Hispanic female was diagnosed with peripartum cardiomyopathy at 30 weeks’ gestation. She became
refractorily inotrope-dependent with a cardiac index of 1.4,
pulmonary vascular resistance of 3.5 to 4.5 Wood units, right
atrial pressure of 24 mmHg, and pulmonary capillary wedge
pressure of 22 mmHg, eventually developing cardiogenic
shock and multiorgan dysfunction. Because of continued
low output, she received an Abiomed 5000 paracorporeal
biventricular pneumatic assist device (BiVAD) and was listed
as a status 1A transplant candidate.
Following BiVAD implantation, the patient developed
severe hemolysis, with plasma hemoglobin levels peaking at
595 mg/dL (Figure 1) on the third postoperative day and a
total bilirubin reaching 13.1 mg/dL (Figure 2).
Transesophageal echocardiogram (TEE) demonstrated
turbulence above the pulmonic valve and massive PI that
correlated with RVAD flow rate (Figure 3).
In order to decrease shear stresses, both pumps were
returned to right-sided driving pressures with minimal vacuum. Hemolysis continued following these adjustments—
albeit to a lesser extent—with plasma hemoglobin levels of
approximately 200 mg/dL.
We believed the PI to be secondary to the jet from
the outflow cannula of the RVAD on the pulmonic valve
and also likely responsible for the high shear stresses and
hemolysis. When the rate of the right ventricular pump was
decreased, TEE showed improvement in right ventricular
function (as compared to that intraoperatively), with maintenance of central venous pressure, near normal pulmonary
artery pressures, and excellent left-sided flows. With the
improvement in right heart function seen by the seventh
postoperative day and continuing RVAD-induced hemolysis,
2
Case Reports in Transplantation
Plasma hemoglobin (mg/dL)
700
600
500
400
300
[1]’s
200
100
0
0
50
100
150
200
Hours post-BiVAD implantation
250
Figure 1: Plasma hemoglobin (mg/dL) following biventricular
assist device (BiVAD) implantation.
Figure 3: Transesophageal echo demonstrating the pulmonary
insufficiency was believed to be secondary to the position of the
outflow cannula of the right ventricular assist device.
Total bilirubin (mg/dL)
14
12
10
8
6
4
2
0
0
100
200
300
Hours post-BiVAD implantation
400
Figure 2: Total bilirubin (mg/dL) following biventricular assist
device (BiVAD) implantation.
she was accordingly taken to the operating room for removal
of the RVAD.
The patient tolerated the RVAD explant well, and a
postoperative TEE showed no residual PI. Additionally,
markers of hemolysis continued to decline. After reoperation
for tamponade following explant, the left heart remained
device-dependent, but right heart function was equivocal,
requiring significant inotropic support. At this point, a donor
heart became available, and 14 days after the BiVAD implantation, the patient underwent an uneventful orthotopic
cardiac transplantation and removal of the LVAD. During
the recipient cardiectomy, the native pulmonary valve was
found to be structurally normal on inspection. The patient
had an uncomplicated recovery and was discharged home on
the tenth postoperative day.
2. Discussion
Cardiac transplantation offers the greatest morbidity and
mortality benefit for patients experiencing end-stage heart
failure; however, the scarcity of donor hearts limits its viability as a treatment option. Yet, with continuing developments
in mechanical circulatory support technology, ventricular
assist devices are becoming more reliable and patient outcomes with such devices are improving. The VAD can be
used as a bridge to recovery, a bridge to transplantation
until a donor heart is obtained, or as destination therapy
for those patients who are not transplant candidates [1].
In those patients who qualify for cardiac transplantation,
the primary indications for VAD implantation as bridge-totransplant therapy are refractory arrhythmia or worsening
hemodynamics, in spite of maximal inotropic support [2].
The ultimate clinical goals of VAD therapy are to restore
adequate blood flow, preserve end-organ function, and
provide effective decompression of the failing ventricle(s).
With a relatively unsophisticated design, VADs augment
ventricular function, hence supporting systemic perfusion—
by mechanically pumping blood from the RV to the pulmonary circulation with an RVAD or from the LV to the
systemic circulation through the aorta with an LVAD. The
inflow cannula of the LVAD—usually placed at the apex of
the heart—directs blood from the left atrium or ventricle
into the pump. The outflow cannula is anastomosed to the
ascending aorta where blood can then reach the systemic
circulation. In the RVAD, the inflow cannula directs blood
from the right atrium or ventricle to the pump, and the
outflow cannula is anastomosed to the main pulmonary
artery [3].
In this case, the low position of the RVAD outflow
cannula (chosen to facilitate later transplantation) produced
a jet of blood such that the velocity across the pulmonic
valve was increased. The calculated Reynolds number is
increased behind the pulmonary valve because of the mixing
of blood flowing from the right ventricle and the RVAD,
thus accounting for the pulmonary insufficiency and clinical
significant hemolysis. As the output from the RVAD was
decreased, the pulmonary regurgitation also decreased, further suggesting that the velocity of the jet from the RVAD was
directly responsible for the increased turbulence behind the
pulmonic valve [4].
Additionally, the increased turbulence decreases the
pressure before the pulmonic valve in the right ventricle. In a
classic Bernoulli effect, this widened pressure gradient across
the pulmonic valve increases the velocity of the regurgitated
blood through the pulmonic valve, resulting in greater PI
[5]. This case represents the only report we could find in
Case Reports in Transplantation
the literature detailing significant PI following appropriate
RVAD placement.
Despite the relatively straightforward placement of these
devices, this case demonstrates the necessity of monitoring
flow dynamics within the pump and the heart following VAD
implantation to appropriately address relevant anatomical
and functional factors. This same mechanism may account
for the aortic regurgitation now being seen with continuous
flow devices.
References
[1] E. A. Rose, A. C. Gelijns, A. J. Moskowitz et al., “Long-term use
of a left ventricular assist device for end-stage heart failure,” The
New England Journal of Medicine, vol. 345, no. 20, pp. 1435–
1443, 2001.
[2] R. Krishnamani, D. Denofrio, and M. A. Konstam, “Emerging
ventricular assist devices for long-term cardiac support,” Nature
Reviews Cardiology, vol. 7, no. 2, pp. 71–76, 2010.
[3] S. Chumnanvej, M. J. Wood, T. E. MacGillivray, and M. F. V.
Melo, “Perioperative echocardiographic examination for ventricular assist device implantation,” Anesthesia and Analgesia,
vol. 105, no. 3, pp. 583–601, 2007.
[4] N. B. Wood, “Aspects of fluid dynamics applied to the larger
arteries,” Journal of Theoretical Biology, vol. 199, no. 2, pp. 137–
161, 1999.
[5] A. P. Yoganathan, E. G. Cape, H. W. Sung, F. P. Williams,
and A. Jimoh, “Review of hydrodynamic principles for the
cardiologist: applications to the study of blood flow and jets
by imaging techniques,” Journal of the American College of
Cardiology, vol. 12, no. 5, pp. 1344–1353, 1988.
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