Ann Thorac Surg 2004;77:1851-1853
© 2004 The Society of Thoracic Surgeons
How to do it
Intraabdominal placement of a Novacor ventricular assist system by using an expanded polytetrafluoroethylene pouch
Goro Matsumiya, MDa*,
Yuji Miyamoto, MDa,
Norihide Fukushima, MDa,
Osamu Monta, MDa,
Yoshiki Sawa, MDa,
Hikaru Matsuda, MDa
a Department of Surgery, Division of Cardiovascular Surgery, Osaka University Graduate School of Medicine, Osaka, Japan
Accepted for publication July 17, 2003.
* Address reprint requests to Dr Matsumiya, Department of Surgery, Division of Cardiovascular Surgery, Osaka University Graduate School of Medicine (E1), 2-2 Yamada-oka, Suita, Osaka 565-0871, Japan
e-mail: matsumg{at}surg1.med.osaka-u.ac.jp
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Abstract
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The location of the pump pocket for the left ventricular assist system is of great importance because of its direct relation to subsequent complications. The Novacor device has usually been implanted at the space behind the rectus muscle, which leads to occasional bleeding from raw muscle surfaces and to subsequent pocket infection. Although intraabdominal placement causes less bleeding and is more refractory to later pocket infection, direct contact with the visceral organs sometimes causes serious complications. We constructed a pouch from an expanded polytetrafluoroethylene sheet, and this enabled intraabdominal placement of the Novacor device.
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Introduction
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An implantable left ventricular assist system (LVAS) requires a pocket for its intracorporeal placement. The location and the method for its creation have been attracting increasing attention because they directly relate to the short- and long-term results [1]. We report a technique to place the Novacor LVAS (WorldHeart Corp, Ottawa, Ontario, Canada) in an intraperitoneal space by using a pouch constructed from an expanded polytetrafluoroethylene (ePTFE) sheet.
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Technique
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The operation is performed through a median sternotomy. The inferior part of the incision is extended down to the umbilicus, and the abdomen is opened. A pericardium is opened, and preparation is made for an emergent cannulation. The diaphragmatic attachment to the left costal margin is divided to the level of the left ventricular apex. A 1-mm ePTFE sheet measuring 20 x 30 cm in width is used to construct a pouch. The posterior side of the pouch facing the abdominal cavity is made longer than the anterior side so that the superior rim of the pouch can be anastomosed with the diaphragmatic edge. The use of a mock device in the pouch facilitates the decision of pouch configuration. The side of the pouch is sutured along the edge of the mock device with a polypropylene continuous suture so that the space around the device becomes minimal. A small hole is made at the anteroinferior portion of the pouch to pass the driveline (Fig 1).
A subcutaneous tunnel is made from the right side of the abdominal wall into the left lower part of the abdominal cavity. The driveline is passed through the tunnel, and the device is placed in the abdominal cavity with the ePTFE pouch. The position of the LVAS is tested for the proper placement of the inflow graft in relation to the left ventricular apex. The superior rim of the pouch is sutured to the anterior cut edge of the left diaphragm. The left rim of the pouch is sutured to the left side of the abdominal wall, and the right rim is sutured to the cut edge of the peritoneum. The caudal side of the pouch is not sutured to the abdominal wall because this area is securely attached to the abdominal wall by the driveline and because the space between the pump pocket and the abdominal wall seems too small for viscera to pass into the pocket (Fig 2).
This may cause the omentum to accumulate around the driveline and prevent the driveline infection from spreading into the pocket and may also allow the accumulated fluid to drain into the peritoneal cavity. We make the pouch, insert the LVAD, and then place them into the abdominal cavity, rather than performing the anastomosis of the ePTFE sheet to the abdominal borders first and then placing the device over the sheet, because it is easier to make the proper configuration of the pouch and leave minimal space around the LVAD in the former way. The rest of the procedure is performed as previously described [2]. We use hypothermic cardioplegic arrest during the anastomosis of the outflow graft to the ascending aorta, the apical coring, and the inspection of the left ventricular cavity to discover the thrombus [3]. We routinely use aprotinin during cardiopulmonary bypass and use nitric oxide inhalation when terminating the cardiopulmonary bypass, to aid the right ventricle. We place chest tubes into the mediastinum and the pleural space as needed and place additional closed system drains with 2 soft silicone elastomer tubes in the pocket: 1 over the device and 1 inferior to the device. We remove the pocket drains when drainage becomes less than 50 mL/d. Because there is no dissected space in the pocket, drainage stops when the mediastinal drainage becomes minimal. The drains can usually be removed within 4 to 5 days. Closure of the abdominal wall can be performed in the usual manner.
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Fig 1. A 1-mm expanded polytetrafluoroethylene (ePTFE) sheet covers the posterior side and the anterior half of the Novacor device, and both sides are closed along the device with a continuous suture. A driveline comes out from a small hole at the inferior portion.
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Fig 2. The Novacor device is placed intraabdominally with the polytetrafluoroethylene pouch. The edge of the pouch is sutured to the left side of the abdominal wall, the cut edge of the diaphragm, and the peritoneum. The caudal side is left open.
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Comment
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An ever-increasing waiting time for heart transplants and recent favorable results of LVAS destination therapy are stimulating interest in using the implantable LVAS for long-term support [4]. As shown in many reports, infection is one of the leading factors that preclude long-term LVAS use [5]. The location of the LVAS pump pocket is of great importance because it is one of the factors that directly relates to subsequent complications, including infection [1]. Because early experience with intraperitoneal implantation resulted in perforated colon, the Novacor LVAS has been usually implanted in the space between the rectus muscle and its posterior fascia (intraabdominal wall) or between the peritoneum and the posterior fascia (preperitoneal) [2]. However, accumulating experience has shown that the intraperitoneal placement is more resistant to infection than the extraperitoneal placement [1]. The direct contact of the device with the raw surface of the rectus muscle causes bleeding in the pocket and formation of hematoma that becomes a good target for infectious organisms. Because patients with the Novacor LVAS require intense anticoagulation therapy, bleeding in the pocket sometimes forces the suspension of anticoagulation therapy and provides an increased risk of thromboembolic complications. The preperitoneal insertion is another useful option, but this is often difficult to perform in thin or malnourished patients with little preperitoneal fat. The dissection of the space in these patients leads to opening in the peritoneum and subsequent herniation of the intraabdominal organs. Conversely, intraabdominal placement of the LVAS has been associated with fewer infectious and bleeding complications. This is extremely important in cases aiming at long-term support. The abdominal cavity is rich with immune-responsive cells, and the omentum is capable of localizing and eventually healing the infection around the device [6]. Major disadvantages of this approach are direct contact with the stomach, intestine, and colon, resulting in their perforation [2]. Herniation of abdominal organs into the thoracic cavity has also been reported. The explantation of the device at the time of transplantation may be hazardous because of the risk of inadvertent injury to the abdominal viscera.
We developed a simple technique that enables intraperitoneal placement of the Novacor LVAS without direct contact with the visceral organs. The fluid collection in the pocket is of concern with this technique. Therefore, we drain the space around the pump by leaving soft drainage tubes for several days and leave the caudal space of the pocket open to the peritoneal cavity so that the fluid can be drained out of the pocket. This technique may be especially useful in patients with a small body size and thin abdominal wall. Because diffuse coagulopathy is sometimes encountered in patients with profound shock at the time of LVAS implantation, this technique may contribute to decreased bleeding and thus enable faster postoperative recovery.
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References
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- Wasler A., Springer W.E., Radovancevic B., Myers T.J., Stutts L.A., Frazier O.H. A comparison between intraperitoneal and extraperitoneal left ventricular assist system placement. ASAIO J 1996;42:M573-576.[Medline]
- Pennington D.G., McBride L.R., Swartz M.T. Implantation technique for the Novacor left ventricular assist system. J Thorac Cardiovasc Surg 1994;108:604-608.[Abstract/Free Full Text]
- Vigano M., Martinelli L., Minzioni G., Rinaldi M., Pagani F. Modified method for Novacor left ventricular assist device implantation. Ann Thorac Surg 1996;61:247-249.[Abstract/Free Full Text]
- Rose E.A., Gelijns A.C., Moskowitz A.J., et al. Long-term mechanical left ventricular assistance for end-stage heart failure. N Engl J Med 2001;345:1435-1443.[Abstract/Free Full Text]
- Herrmann M., Weyand M., Greshake B., et al. Left ventricular assist device infection is associated with increased mortality but is not a contraindication to transplantation. Circulation 1997;95:814-817.[Abstract/Free Full Text]
- Matsumiya G., Nishimura M., Miyamoto Y., Sawa Y., Matsuda H. Successful treatment of Novacor pump pocket infection by omental transposition. Ann Thorac Surg 2003;75:287-288.[Abstract/Free Full Text]
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Abstract
Introduction
