A Modified Cannulating Technique for the BVS5000
By Luo, X J Hu, S S; Sun, H S; Liu, P; Zhang, Y
The aim of this study was to report on a modified cannulating method for the BVS5000 left ventricular assist device. From April 2005 to April 2006, a BVS5000 device was implanted using a modified cannulating method in 7 postcardlotomy male patients after coronary artery bypass grafting for left ventricular support The inflow cannula was inserted into the left atrial artery through a segment of bovine jugular vein and the arterial cannula into the femoral artery. Five patients were successfully weaned from the BVS5000 after recovery of heart function and were discharged from hospital. The BVS5000 was explanted using a minimally invasive technique. The weaning procedure was completed bedside in the intensive care unit under local anesthesia; resternotomy was not necessary. The modified technique is a simpler, safer and more minimally invasive method for selected patients supported by the BVS5000. KEY WORDS: Heart assist devices – Minimally invasive surgical procedures – Heart failure, congestive.
Within the epidemic of heart failure, left ventricular assist devices (LVADs) have become an important means for preserving end- organ function and providing effective decompression of failing ventricles. The Abiomed BVS5000 (Abiomed Inc. Danvers, MA, USA) a LVAD that can be easily used for shortterm support, especially as a bridge-to-recovery method in postcardiotomy patients.
After recovery, however, the devices are normally explanted by median resternotomy associated with extensive dissection of adhesions, which can increase morbidity and mortality.1,2 To avoid these complications, we used a modified cannulating method for BVS5000 LVADs.
Technique
A size 32 Fr or 36 Fr atrial cannula is used for inflow. The arterial outflow cannula comprises a 42 Fr atrial cannula attached to a 10-mm Hemashield graft (Meadox Medicals Inc., Oakland, CA).
Implantation of the BVS5000 LVADs is supported by cardiopulmonary bypass (CPB) through median sternotomy. The arterial outflow cannula is anastomosed (end-to-side) to the femoral artery by a continuous suture with 4-0 prolene. After passing through a subcutaneous canal (5-8 cm), it pierces the skin 15 cm above the knee. The distal end of the arterial outflow cannula is then connected to the pump.
An incision (2-3 cm) in the left atrium is made in the interatrial grove. A segment of bovine jugular vein (18 mm in diameter, approximately 15 cm in length) is anastomosed to the interatrial grove incision by a continuous suture with 4-0 prolene. Two purse-string sutures (4-0 prolene) are prepared beforehand around the vessel wall of the bovine jugular vein, with a segment of sterile silastic casing kept on each suture for tightening the purse strings. The inflow cannula is then inserted into the left atrium through the bovine jugular vein. The purse-string sutures are tightened to immobilize the cannula and prevent bleeding. The inflow cannula pierces out at the right epigastrium through a subcutaneous canal (5-7 cm in length) and is connected to the pump. In order to simplify the weaning procedure, the ends of the two purse-string sutures are located just below the xiphoid process before closing the incision.
Weaning from the device can be accomplished bedside in the intensive care unit (ICU). Resternotomy is not necessary. Only local anesthesia is needed. Through a small incision (approximately 8 cm) below the xiphoid process, the inflow cannula and the two purse- string sutures are easily exposed. After successfully terminating assistance of the LVAD, the casings on the purse-string sutures are loosened temporarily, so that the inflow cannula can be quickly pulled out through the bovine jugular vein. The casings are then tightened completely and fixed firmly with the distant end of the bovine jugular vein.
The arterial outflow cannula is exposed through the original incision. The outflow graft is divided as close as possible to the femoral artery anastomosis. The residual graft stump (2-3 mm in length) is oversewn and the device is then explanted.
Clinical experience
From April 2005 to April 2006, 7 male patients (age range 53-65 years, mean 59-3+-5.1 years; mean body surface area 1.8+-0.1 m2) were implanted with a BVS5000 device for left ventricular support in this modified way at Fu Wai Hospital. All were postcardiotomy patients after coronary artery bypass grafting (CABG), which were supported for bridge to recovery. Support duration was 5.4+-2.8 d (3- 1 Id), with a support flow rate of 38-4.3L/min. The respiratory support duration was 2.1+1.9 d (0.8-6 d). After BVS5000 implantation, thoracic drainage in the first three days was 1 958+- 699 mL. None of the patients needed revision for bleeding.
Five patients were successfully weaned from the BVS5000 after recovery of heart function and were discharged from hospital. The BVS5000 devices were weaned bedside in the ICU under local anesthesia; resternotomy was not necessary. There was no severe bleeding during the weaning procedure. At discharge from hospital, the left ventricular diastolic diameter (LVDD) had decreased to 55.3+-6.0 mm and the left ventricular ejection fraction (LVEF) had increased to 45+-9%, which were improved versus the preoperative values (preoperative LVDD 70.6+-6.2 mm, LVEF 32+-4%). The remaining 2 patients died from embolic shock during the support period. There was no infection caused by the bovine graft.
Discussion
Dennis et al. 3 were the first to describe the left atrial-to- femoral artery bypass system by jugular approach. Consecutively, left atrial-to-femoral arterial LVADs were used chiefly in patients who could not be weaned from CPB after cardiothoracic surgery.4 For these bridge-to-recovery patients, minimal invasiveness for the myocardium and convenient weaning from LVADs are important considerations.
Compared with other kind of LVADs, the BVS5000 has longer cannulae that connect to an extracorporeal pump. It facilitates cannulating the left atrial and femoral arteries at the same time. Resternotomy for weaning from the BVS5000 can be avoided by using the modified cannulating method described in this study, The whole weaning procedure can be accomplished bedside in the ICU.
However, there are drawbacks to this modified technique. It should not be used in patients with severe atherosclerosis of the femoral artery. Moreover, patient movement is partly limited during the support period. It is more suitable for short-term support.
In order to ensure sufficient perfusion in patients with severe atherosclerosis of the femoral artery, ascending aorta-left atrial cannulating is regularly performed. Resternotomy is needed for the weaning procedure. However, the bovine graft is the one we used for left atrial cannulating. With use of a bovine graft, decannulation of the left atrial cannula without CPB becomes much easier and is also beneficial for controlling bleeding. During the same period, we used this modified method for ascending aorta-left atrial cannulation in 6 patients at Fu Wai Hospital.
In conclusion, our experience indicates that the modified cannulation technique is a simpler, safer and more minimally invasive method in some patients supported by the BVS5000.
References
1. Haj-Yahia SM, Birks EJ, Hardy J, Yacoub MH, Khaghani A. Minimally invasive technique for explantation of right ventricular assist devices. Ann Thorac Surg 2006;82: 1547-8.
2. Tansley P, Yacoub MH. Minimally invasive technique for explantation of left ventricular assist devices. J Thorac Cardiovasc Surg 2002;124:189-91.
3. Dennis C, Carlens C, Senning A, Hall DP, Moreno JR, Cappelletti RR etal. Clinical use of a cannula for left heart bypass without thoractomy. Ann Surg 1962;156:623-7.
4. Thiele H, Lauer B, Hambrecht R, Boudriot E, Cohen HA, Schuler G. Reversal of cardiogenic shock by percutaneous left atrial- tofemoral arterial bypass assistance. Circulation 2001;104:2917-22.
X. J. LUO, S. S. HU, H. S. SUN, P. LIU, Y. ZHANG
Department of Cardiovascular Surgery
Fu Wai Hospital, Peking Union Medical College
Beijing, P. R. China
Received on April 26, 2007.
Accepted for publication on July 9, 2007.
Address reprint requests to: S. S. Hu, Department of Cardiovascular Surgery, Fu Wai Hospital, Peking Union Medical College. No.l67, Beilishi Road, Beijing, 100037, P. R. China. E- mail: huss@vip.sohu.com
Copyright Edizioni Minerva Medica Aug 2007
(c) 2007 Journal of Cardiovascular Surgery. Provided by ProQuest Information and Learning. All rights Reserved.