Ann Thorac Surg 2002;73:994-996
© 2002 The Society of Thoracic Surgeons
How to do it
Alternate technique for implantation of left ventricular assist system: left thoracotomy for reoperative cases
Shawn L. Tittle, MDa,
Divakar Mandapati, MDa,
Gary S. Kopf, MDa,
John A. Elefteriades, MD*a
a Section of Cardiothoracic Surgery, Yale University School of Medicine, New Haven, Connecticut, USA
Accepted for publication October 30, 2001.
* Address reprint requests to Dr Elefteriades, Section of Cardiothoracic Surgery, Yale University School of Medicine, 121 FMB, 333 Cedar St, New Haven, CT 06520 USA
e-mail: john.elefteriades{at}yale.edu
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Abstract
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Reoperation for Novacor left ventricular assist device placement after prior cardiac surgery is fraught with multiple technical challenges. We have found that a thoracotomy approach obviates these dangers very favorably. The technique is performed off bypass except for apical coring and apical connection. Novacor outflow is to the descending aorta. This approach has been found safe, quick, and effective.
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Introduction
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The Novacor device (World Heart Corporation, Ottawa, Canada) is a left ventricular assist system designed to operate as a bridge to cardiac transplantation in patients with nonreversible left ventricular failure [1, 2]. The Novacor device is typically implanted via sternotomy [3–5]. In redo operations, especially when there are prior patent bypass grafts, the sternotomy approach can be difficult and dangerous. Bypass grafts are vulnerable to injury. The patent internal mammary artery can be troublesome technically and can complicate cardioplegic arrest of the heart. Also, room on the ascending aorta for the Novacor outflow graft may be limited due to previous proximal anastomoses. Typically in end-stage heart failure, the right ventricle is tensely distended and expressly vulnerable to catastrophic injury during repeat sternotomy. Postoperative bleeding from the redissected planes, in view of preexisting coagulopathy and deliberate anticoagulation, can be life-threatening. Due to all these factors, traditional placement of the Novacor via sternotomy in redo cases is a formidable procedure.
In this article, we describe an alternate implantation technique for Novacor placement in the redo setting through a left thoracotomy. We have used this technique effectively in 3 patients with left ventricular failure at Yale-New Haven Hospital.
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Technique
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The sequence of operation is as follows. An anterolateral left thoracotomy is performed in the fifth intercostal space. Simultaneously, a pre-peritoneal pocket is created through a midline upper abdominal incision into the linea alba (Fig 1).
The cannulation approach is as follows. The main pulmonary artery can be cannulated for cardiopulmonary bypass inflow. If the main pulmonary artery is inaccessible (eg, overlying patent internal mammary graft), the left femoral vein can be utilized. Arterial cannulation can be done directly into the low descending thoracic aorta. The left femoral artery or femoral vein can be utilized as alternative cannulation sites, if so preferred.
Directly at the apex of the heart, a small circle of pericardium is incised in cruciate fashion and a localized portion of the cardiac apex is mobilized (Fig 2).
Approximately 12 anchoring stitches are placed in the apical myocardium, with a buttressing Teflon (Impra Inc, subsidiary of L.R. Bard, Tempe, AZ) strip.
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Fig 2. View of left ventricular cannulation site via left thoracotomy. Note cruciate incision in the pericardium.
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The Novacor device is situated in the pre-peritoneal pocket previously created. The conduits to and from the Novacor device are passed through openings created in the diaphragm anteriorly near its left costal insertion.
The descending aorta is dissected and prepared for anastomosis. A side-biting clamp is placed on the aorta, and the outflow graft from the Novacor device is anastomosed to the descending aorta in end-to-side fashion. The outflow graft is routed underneath the inflow graft. These portions of the procedure are performed without cardiopulmonary bypass.
After these steps are completed, normothermic cardiopulmonary bypass is instituted. The heart is fibrillated by electrical stimulation. A core of muscle is excised from the apex of the heart. We prefer a freehand excision (without the coring device). The inflow graft of the Novacor is then inserted into the apex of the heart and secured by tying the 12 anchoring sutures. The pericardium is reapproximated by interrupted sutures to the Teflon ring for extra security; this reapproximation also eliminates any potential space for bleeding.
After this, sinus rhythm is reestablished in the patient by removing the fibrillating electrodes and defibrillating if necessary. The patient is then placed in Trendelenburg position, and the descending aorta is clamped above the outflow Novacor anastomosis to prevent air embolus to the heart or brain (Fig 3).
The Novacor device is then activated, and the left ventricular output is augmented progressively in standard fashion and cardiopulmonary bypass weaned. Once the Novacor has been running for several minutes, the descending aortic clamp is removed and the patient is returned to the flat position.
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Results
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Average cardiopulmonary bypass time has been 38 minutes. No cross-clamping of the ascending aorta is required, and no cardioplegia is necessary.
The procedure has been well tolerated in all patients (see Table 1). We used the pulmonary artery for inflow in 1 patient and the femoral vein in 2. We used the descending aorta for arterial cannulation in 1 patient and the femoral artery in 2. One critically ill patient was reexplored for excess drainage on the 1st postoperative day, with no bleeding sites found. One patient, previously dry, bled on the 4th postoperative day while receiving heparin and Coumadin; reexploration was negative, and there was no recurrence. Right heart function was adequate in all cases. Two patients survived the acute phase and 1 was later successfully transplanted. At transplant, the outflow conduit was stapled near its attachment to the descending aorta and divided.
This method is not recommended when significant descending aortic pathology is present. In 1 additional patient, we attempted this procedure but aborted the operation due to severe atherosclerotic disease in the descending thoracic aorta. This patient, who had been unstable on maximal inotropic support preoperatively, also had severe ascending atheromatous disease, precluding even ascending aortic connection of the Novacor outflow. His support was withdrawn and he expired several days after thoracotomy. Intraoperative transesophageal echocardiography is useful for assessment of the quality of the descending aorta, as well as for general purposes (assessment of cardiac function and air removal). We do now recommend that if the thoracotomy approach is contemplated for Novacor placement, either transesophageal echocardiography or computerized tomography of the aorta be performed to evaluate the descending aorta for atheroma. Since flow is retrograde with this technique, any pathology in the descending aorta proximal to the outflow graft anastomosis represents a potential nidus for embolization to the brain.
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Comment
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The thoracotomy approach has become our procedure of choice for left ventricular assist device placement in patients with prior coronary artery bypass grafting. This technique renders an otherwise troublesome procedure quick, straightforward, and tolerable for both the patient and the surgical team.
Advantages of this approach are multiple:
- Reentry injury from repeat sternotomy is avoided.
- Minimal dissection of cardiac adhesions is required. Only an extremely small apical area of pericardium is freed from the cardiac surface. Adhesions at the apex are typically flimsy and easy to dissect.
- Prior bypass grafts, especially patent internal mammary grafts, are not vulnerable. The apical site of cannulation is far distal to anterior descending, diagonal, and circumflex anastomoses. Embolization from graft manipulation is avoided.
- Potential sites for bleeding are minimized, as dissection of the heart is limited and there is little potential space around the inflow cannula.
- Myocardial protection becomes a non-issue, as the heart remains perfused.
- Cardiopulmonary bypass time is minimal, as only apical coring and connection need to be performed on bypass.
- Air protection is enhanced, as the descending aorta is temporarily clamped proximal to the outflow graft when the Novacor is started, obligating any air to flow to the lower body, where it is benign in comparison to cardiac or cerebral air embolism.
We recommend this thoracotomy approach as an alternative for left ventricular assist device placement in the reoperative setting, especially in patients with prior coronary artery bypass.
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References
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Robbins R.C., Oyer P.E. Bridge to transplant with the Novacor left ventricular assist system. Ann Thorac Surg 1999;68:695-697.[Abstract/Free Full Text]
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El-Banayosy A., Deng M., Loisance D.Y., et al. The European experience of Novacor left ventricular assist (LVAS) therapy as a bridge to transplant: a retrospective multi-centre study. Eur J Cardiothorac Surg 1999;15:835-841.[Abstract/Free Full Text]
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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]
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Loisance D., Cooper G.J., Deleuze P.H., et al. Bridge to transplantation with the wearable Novacor left ventricular assist system: operative technique. Eur J Cardiothorac Surg 1995;9:95-98.[Abstract]
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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]
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Abstract
Introduction
