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\begin{document}

\title{AngioVac Suction Embolectomy Using a Roller Pump: Operative Technique}



\author[1]{Michael Shang}%
\author[1]{Touraj Rajabipour}%
\author[1]{Prashanth Vallabhajosyula}%
\affil[1]{Yale School of Medicine}%


\vspace{-1em}



  
  \date{June 14, 2024}


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\selectlanguage{english}
\begin{abstract}
AngioVac suction embolectomy is recommended by the manufacturer to be
performed with a centrifugal pump due to safety considerations. However,
roller head pumps are significantly cheaper to use, and thus may be more
readily available during shortages and in resource poor settings. We
present the technique of Angiovac suction embolectomy being successfully
performed with a roller pump to evacuate a clot-in-transit in the
inferior vena cava and right atrium, along with discussion of important
safety caveats.%
\end{abstract}%



\sloppy


\textbf{AngioVac Suction Embolectomy Using a Roller Pump: Operative
Technique}

\textbf{Running title: \emph{Roller pump suction embolectomy}}

Michael Shang BS\textsuperscript{1}, Touraj Rajabipour BS, MHS,
CCP\textsuperscript{1}, Prashanth Vallabhajosyula MD,
MS\textsuperscript{1}

Division of Cardiac Surgery, Yale University School of Medicine, New
Haven, CT

\textbf{Conflict of Interest:} We have no conflicts of interest to
report.

\textbf{Sources of Funding:} We have no sources of funding to report.

\textbf{Institutional Review Board:} Institutional Review Board review
was waived under guidelines set forth by our institution.

\textbf{Informed Consent:} Informed consent was waived as the subject of
the report is deceased and the information presented is de-identified
according to safe-harbor deidentification guidelines. To our knowledge,
the information presented cannot be used alone or in combination with
other information to uniquely identify the subject.

\textbf{Corresponding Author:}

Prashanth Vallabhajosyula

330 Cedar St. PO Box 208062

New Haven, CT 06520-8062

Email: prashanth.vallabhajosyula@yale.edu

Phone: 203-785-5000

\textbf{Word count:} 1408

\emph{Abstract}

AngioVac suction embolectomy is recommended by the manufacturer to be
performed with a centrifugal pump due to safety considerations. However,
roller head pumps are significantly cheaper to use, and thus may be more
readily available during shortages and in resource poor settings. We
present the technique of Angiovac suction embolectomy being successfully
performed with a roller pump to evacuate a clot-in-transit in the
inferior vena cava and right atrium, along with discussion of important
safety caveats.

\emph{Text}

\textbf{Introduction}

The AngioVac device (AngioDynamics, Latham, NY) is currently approved
for suction embolectomy of venous thromboemboli. The AngioVac system
consists of a catheter with a funnel-shaped tip connected to a
veno-venous (VV) extracorporeal bypass circuit that filters aspirated
blood before returning it systemically. The literature documenting its
use unanimously reports using a centrifugal pump, as recommended by the
manufacturer.\textsuperscript{1-3} However, roller pumps are an
attractive alternative in this situation due to lower cost, especially
in resource poor settings or during times of severe equipment shortage.
Such a situation occurred at our institution during the peak of the
COVID-19 pandemic. We report the use of a roller pump with the AngioVac
device to extract a right atrial (RA) clot-in-transit in a patient with
pulmonary embolism (PE) and severe cardiogenic shock.

Informed consent was waived under guidelines set forth by our
institution's Institutional Review Board.

\textbf{Case}

A 76-year-old male with history of coronary artery disease and chronic
obstructive pulmonary disease presented to an outside hospital with
acute-onset dyspnea. The patient was hemodynamically stable with initial
laboratory evaluation significant for anion-gap metabolic acidosis,
venous lactate 7.6, D-dimer 11.65, and proBNP 17,056; SARS-CoV-2 RNA
testing was negative. CT angiography of the chest revealed saddle
pulmonary embolus with near complete occlusion of the main pulmonary
arteries and evidence of right ventricle (RV) strain. The patient was
treated initially with intravenous heparin. Despite this, the patient
began experiencing increasing dyspnea with repeat echocardiogram showing
a new 4.8cm-by-1.4cm mobile thrombus in the RA going in and out of the
RV during the cardiac cycle with additional clot extending into the
inferior vena cava (IVC) (\textbf{Figure 1} ). Due to concerns for
distal embolization causing massive PE, thrombolytic therapy was
deferred and the patient was transferred to our facility for urgent
suction embolectomy using the AngioVac system.

\textbf{Operative Technique}

The procedure was performed using C-arm fluoroscopy and transesophageal
echocardiography (TEE) by a cardiac surgeon experienced in
catheter-based and surgical embolectomy. Intraoperative TEE demonstrated
a markedly dilated RV and underfilled left ventricle (LV) with
hyperdynamic LV function. Upon general anesthesia induction and
intubation, guidewires were placed in both common femoral veins (CFV)
and advanced into the IVC under fluoroscopic guidance. The patient was
anticoagulated with heparin, and next, a 26F dry-seal sheath (Gore
Medical) was placed in the right CFV for the AngioVac cannula and an 18F
cannula was placed in the left CFV for the reinfusion cannula. The
AngioVac catheter was introduced through the right groin sheath and
advanced into the IVC prior to connecting it to the venous inflow tubing
of the VV bypass circuit after proper deairing maneuvers. The system was
then connected to the roller pump. The AngioVac catheter was carefully
advanced under fluoroscopic and echocardiographic guidance, as the pump
was started at 1 L/min and gradually increased to flow rate of 2.5 L/min
under fluoroscopic and echocardiography guidance. The catheter was then
advanced to the IVC-RA junction, at which point a large thrombus was
suctioned into the filter (\textbf{Figure 2} ). A second thrombus was
evacuated upon further advancement into the RA. We verified that no
remaining clot was visible in the RA and RV using TEE and proceeded to
come off VV bypass by shutting down the pump gradually. Both cannulas
were removed, and groin sites repaired. The entire procedure was without
complications.

\textbf{Discussion}

The AngioVac system is recommended for use with centrifugal pumps
because they are non-occlusive with no risk for cavitation of air.
However, the present case was performed at the height of the COVID-19
pandemic, during which our hospital was experiencing a severe shortage
in centrifugal pump heads due to the sudden increase in utilization for
ECMO support in COVID patients. Given the urgent status of the
procedure, we decided to use a roller pump as it was the only equipment
available at the time. In addition, roller pumps have the added benefit
of being significantly cheaper to use as they do not require replacement
of a centrifugal pump head, which costs \$12,600 per use.

Though the present case was technically successful and without
complications, there are important safety considerations requiring
careful evaluation with the use of roller pumps. First, roller pumps are
occlusive and will continue to pump against any resistance, making them
more likely to result in significant structural damage if the AngioVac
catheter tip gets suctioned against an anatomic structure (i.e. inferior
vena cava, right atrial free wall). Therefore, very gradual flow rate
changes, capping at a low flow rate (2.5 L/ minute in our case),
continuous visualization of the device and short advancements, with the
operative team ready to make immediate adjustments, are required.
Additionally, the AngioVac catheter has been reported to clog when used
to evacuate solid or chronic thrombi.\textsuperscript{2} With a roller
pump, a fully occluded tip may result in cavitation of air as well as
trauma to blood elements due to shear stress from being suctioned around
the occlusion.\textsuperscript{4} These considerations are especially
important as introduction of air into the circuit can potentially be
catastrophic in patients with PE who may already have RV dysfunction.
While roller pumps may be more cost effective, safety is paramount.
Thus, we recommend that this technique only be considered for soft,
fresh thrombi in locations where navigation of the suction tip around
delicate structures and long advancements of the device are not
required.

In the present case, we demonstrate that AngioVac suction embolectomy
can be safely and effectively performed with a roller pump to evacuate
mobile, acute thrombi in the IVC and RA. In situations where centrifugal
pumps are inaccessible, roller head pumps may be considered as an
alternative under specific circumstances, granted precautions are taken
to adjust for its limitations.

\emph{Author Contributions}

MS contributed to the concept and drafting of the manuscript.

TR obtained cost data and contributed to the critical revision and
approval of the manuscript.

PV performed the procedure reported in the article and contributed to
the concept, critical revision, and approval of the manuscript.

\emph{References}

1. Resnick, S.A., D. O'Brien, D. Strain, C. Malaisrie, D. Schimmel, R.
Salem, et al. Single-Center Experience Using AngioVac with
Extracorporeal Bypass for Mechanical Thrombectomy of Atrial and Central
Vein Thrombi. \emph{J Vasc Interv Radiol} . 2016;27:723-729 e1.

2. Schultz, J., A. Andersen, E.L. Grove, L.B. Ilkjaer, and J.E.
Nielsen-Kudsk. Large Solid Right Atrial Thrombus Treated by AngioVac
Catheter-Based Suction Thrombectomy. \emph{Case Rep Cardiol} .
2018;2018:7904064.

3. Michelson, C.M., C.M. Dyke, D.J. Wick, R. Guenther, D. Dangerfield,
and M.E. Wiisanen. Use of a Modified Cardiopulmonary Bypass Circuit for
Suction Embolectomy with the AngioVac Device. \emph{J Extra Corpor
Technol} . 2017;49:299-303.

4. Datt, B., M.B. Nguyen, G. Plancher, M. Ruzmetov, M. O'Brien, A. Kube,
et al. The Impact of Roller Pump vs. Centrifugal Pump on Homologous
Blood Transfusion in Pediatric Cardiac Surgery. \emph{J Extra Corpor
Technol} . 2017;49:36-43.

\emph{Figure Legends}

\textbf{Figure 1:} Transthoracic echocardiogram showing a 4.8cm x 1.4cm
thrombus in the right atrium and extending into the inferior vena cava.

RA: right atrium

TV: tricuspid valve

IVC: inferior vena cava

T: thrombus

\textbf{Figure 2:} Evacuated thrombus from inferior vena cava and right
atrium shown in the AngioVac filter system.

\emph{Figures}

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