Ann Thorac Surg 2004;77:347-350
© 2004 The Society of Thoracic Surgeons
How to do it
Implantation of MicroMed DeBakey VAD through left thoracotomy after previous median sternotomy operations
Roland Hetzer, MD, PhD*a,
Evgenij V. Potapov, MDa,
Yuguo Weng, MD, PhDa,
Henryk Sinawski, MDa,
Friedrich Knollmann, MD, PhDa,
Takeshi Komoda, MDa,
Ewald Hennig, PhDa,
Miralem Pasic, MD, PhDa
a Department of Cardiothoracic and Vascular Surgery, Deutsches Herzzentrum Berlin, Berlin, Germany
Accepted for publication June 3, 2003.
* Address reprint requests to Dr Hetzer, Department of Cardiothoracic and Vascular Surgery, Deutsches Herzzentrum Berlin, Augustenburger Platz 1, 13353 Berlin, Germany.
e-mail: hetzer{at}dhzb.de
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Abstract
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A left lateral thoracotomy was used for implantation of the continuous-flow MicroMed DeBakey left ventricular assist device in 12 patients with previous heart operations through a median sternotomy. This approach avoids reopening the chest through a median sternotomy and reduces the risk of bleeding and subsequent complications.
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Introduction
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The implantation of a left ventricular assist device (VAD) through a left lateral thoracotomy in patients with previous cardiac operations avoids a repeat sternotomy and reduces the risk of bleeding [1, 2]. We report a method for the implantation of a new miniaturized left VAD (MicroMed DeBakey VAD) through a left lateral thoracotomy in patients who have had previous cardiac operations. The MicroMed DeBakey VAD is a small continuous-flow pump designed to be implanted through a median sternotomy. On the basis of our previous experience, we believe that this method avoids the complications associated with repeat sternotomy and simplifies the implantation technique.
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Technique
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Anesthesia and hemodynamic monitoring are performed in the standard manner. Blood pressure measurements are obtained with an arterial line in the right radial and femoral arteries, and a double-lumen endotracheal tube is employed. A Cell Saver device and aprotinin are used to avoid blood loss. Routine perioperative antibiotic therapy is given.
After the patient is placed in the right lateral decubitus position with the left hip rolled back, the groin vessels are prepared, and a left lateral thoracotomy is performed in the fifth intercostal space. Heparin sodium is given, and partial femoral-femoral cardiopulmonary bypass with normothermia is established using long 28F venous and short 24F arterial cannulas. The left lung is deflated, the pulmonary ligament is transected up to the hilum, and the pericardium is opened with only localized dissection of adhesions around the apex. The Teflon ring is attached using twelve mattress stitches of 3-0 felt-reinforced polypropylene positioned around the apex. During a short period of induced ventricular fibrillation, an apical incision is made. Some myocardium is resected within the ring lumen. The ventricular cavity is inspected for trabecular structures crossing the incision and for thrombi, which are meticulously removed.
The inflow cannula of the MicroMed DeBakey VAD is inserted parallel to the septum and secured with polypropylene stitches between the Teflon ring on the apex and the ring on the cannula. The pump is deaired by gently reducing venous drainage, and the heart is defibrillated. The pump is placed inside the chest in the left phrenicocostal sinus, and the inflow cannula is loosely attached to the neighboring rib using a strong polypropylene suture as a sling. The optimal position of the cannula is secured by the sling under transesophageal echocardiographic control.
At this time, the driveline is pulled from the pleural space below the costal arch into abdominal subcutaneous tissue and brought through the skin in the lower left abdominal quadrant with a subcutaneous route of at least 10 cm. The parietal pleura over the middle part of the descending thoracic aorta is opened and, after limited dissection, the aorta is partially excluded using a Satinsky clamp behind the upper part of the hilum. A short longitudinal incision is made, and the distal anastomosis of the outflow graft and the descending thoracic aorta is accomplished using a continuous 4-0 polypropylene suture [2]. Final deairing of the outflow graft is done before the distal anastomosis is completed. The pump is started at low speed; then the distal anastomosis is completed, the clamp is removed, and the pump speed is increased up to 10,000 rpm to achieve unloading of the left ventricle. Reinforcing mattress sutures buttressed with Teflon felt are placed on the distal and proximal ends of the anastomosis and on its lateral aspect to reduce tension on the anastomosis and thus prevent possible bleeding. The flowmeter positioned around the outflow graft is also loosely attached to the inside of the lateral thoracic wall to avoid kinking of the outflow graft (Figs 1, 2).
When the device fully supports
the circulation, the patient is weaned from cardiopulmonary bypass with low doses of epinephrine and inhalation of nitric oxide 40 ppm to support the right ventricle. Heparin is reversed with protamine sulfate, two chest tubes are inserted, and the wound is closed in the usual manner.
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Fig 1. Intraoperative view into opened left chest. The anastomosis between the outflow graft and the descending aorta has been completed (not shown), and the pump has been started. The patient's head is on the right side. (1 = inflow cannula implanted into apex of left ventricle; 2 = pump; 3 = descending aorta; 4 = flowmeter; 5 = distal part of outflow graft.)
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Fig 2. Left anterior oblique view of volume rendering of computed tomographic scan obtained 2 weeks after operation.
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The patient is returned to the supine position, the placement of the pump inflow cannula is again ascertained by transesophageal echocardiography, and the double-lumen endotracheal tube is replaced by a standard endotracheal tube. In the intensive care unit, measures to minimize the risk of right ventricular heart failure are initiated, following the standard management for patients with a left VAD. These measures include use of nitric oxide, restricted fluid replacement, and restricted catecholamine use to maintain cardiac output at a level not higher than necessary for adequate organ perfusion [3]. Anticoagulation with heparin is started 6 hours after cessation of bleeding. The anticoagulation management is performed according to our institutional protocol [4].
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Results
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We have used a left lateral thoracotomy to implant the MicroMed DeBakey VAD with a heparin-coated Carmeda surface in 12 patients (11 men and 1 woman) aged between 46 and 74 years with end-stage ischemic cardiomyopathy (10 patients) or dilated cardiomyopathy (2 patients) after previous cardiac operations. All procedures were carried out on an emergency basis for deterioration of left ventricular function with subsequent secondary organ dysfunction despite use of intravenous inotropic medication and, in three instances, intraaortic balloon counterpulsation. The surgical procedures were successfully carried out and resulted in quick recovery of organ function.
Eight patients had an uneventful postoperative course. Three patients died early postoperatively, and 1 patient died a month after the operation. That patient had a pulmonary infection that led to a postoperative course complicated by sepsis. Of the 12 patients, 6 did not fulfill the criteria for heart transplantation, and the device was implanted with the intent of permanent support.
In general, the pump flow was between 4 and 6 L/min. Transesophageal echocardiographic studies demonstrated that the aortic valve was closed most of the time. Thus, flow to the aortic root was retrograde (Fig 3A).
Blood flow through the coronary arteries was pulsatile because of contractions of the myocardium (Fig 3B). Transcranial Doppler studies showed no microembolic signals in the middle cerebral arteries and less pulsatile blood flow. During follow-up, no thrombosis formation in the aortic root, no microembolic signals in the middle cerebral arteries, and no neurological complications were noted.
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Fig 3. Transesophageal echocardiographic study during less pulsatile flow 1 week after operation: (A) intermittent opening of aortic valve and (B) pulsatile flow through right coronary artery.
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Comment
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Our preliminary experience with 12 patients showed that implantation of the MicroMed DeBakey VAD through a left thoracotomy in patients with previous heart operations is a simple procedure. The MicroMed DeBakey VAD was designed for implantation between the left ventricular apex and the ascending aorta through a median sternotomy. Since the first implantation in November 1998, which was performed by us at our institution [5], this device has been implanted in more than 150 patients worldwide with acceptable results [6]. Implantation of left VADs in this way is a common operation in patients with decompensated end-stage heart failure. However, approximately one third of patients requiring a left VAD have had previous cardiac surgical procedures through a median sternotomy. The technique described simplifies the implantation procedure, requires only minimal preparation of the heart, and avoids the risks of a repeat sternotomy.
The combination of repeat sternotomy and compromised hepatic and renal function resulting from hemodynamic instability with subsequent coagulopathy increases the risk of diffuse postoperative bleeding [7]. This is exacerbated by the fact that the presence of the assist device in the anterior mediastinum may prohibit contact tissue hemostasis of the dissected surfaces. The implantation of an extracorporeal assist device through a left lateral thoracotomy decreases this risk. This technique was initially described for paracorporeal pumps [1, 2], whose placement outside the body is associated with known psychological disturbances [8] and increased risk of infection by way of the cutaneous cannula exit sites. Implantation of the Jarvik 2000 VAD follows the same lateral approach [9].
There has been some concern about retrograde flow in the proximal descending aorta, the aortic arch, and the ascending aorta, in particular when, with extensive unloading of the left ventricle by the assist device, the aortic valve does not open. In such instances, thrombosis of the aortic valve sinus was anticipated [10]. To date, no such complication has been seen in our patients, the coronary blood flow pattern is normal, and no adverse effects are detectable with respect to cerebral function, cerebral blood flow, or any other organ function.
Implantation of the MicroMed DeBakey VAD into the left pleural space is easily performed through a lateral thoracotomy, and the complications associated with repeat sternotomy and long-term use of extracorporeal cannulas and a pump can be avoided. Using this technique, we implanted a MicroMed DeBakey VAD as permanent support in 6 patients. The longest follow-up is 6 months, and there have been no complications.
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Acknowledgments
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We thank Anne M. Gale of the Deutsches Herzzentrum Berlin for editorial assistance.
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References
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- Loebe M., Weng Y., Müller J., et al. Successful mechanical circulatory support for more than two years with a left ventricular assist device in a patient with dilated cardiomyopathy. J Heart Lung Transplant 1997;16:1176-1179.[Medline]
- Pasic M., Bergs P., Hennig E., Loebe M., Weng Y., Hetzer R. Simplified technique for implantation of a left ventricular assist system after previous cardiac operations. Ann Thorac Surg 1999;67:562-564.[Abstract/Free Full Text]
- Potapov E.V., Sodian R., Loebe M., Drews T., Dreysse S., Hetzer R. Revascularization of the occluded right coronary artery during left ventricular assist device implantation. J Heart Lung Transplant 2001;20:918-922.[Medline]
- Koster A., Loebe M., Hansen R., et al. Alterations in coagulation after implantation of a pulsatile Novacor LVAD and the axial flow MicroMed DeBakey LVAD. Ann Thorac Surg 2000;70:533-537.[Abstract/Free Full Text]
- Potapov E.V., Loebe M., Nasseri B.A., et al. Pulsatile flow in patients with a novel nonpulsatile implantable ventricular assist device. Circulation 2000;102(19 Suppl 3):183-187.
- Noon G.P., Morley D.L., Irwin S., Abdelsayed S.V., Benkowski R.J., Lynch B.E. Clinical experience with the MicroMed DeBakey ventricular assist device. Ann Thorac Surg 2001;71:S133-138.[Abstract/Free Full Text]
- Frazier O.H., Rose E.A., McCarthy P., et al. Improved mortality and rehabilitation of transplant candidates treated with a long-term implantable left ventricular assist system. Ann Surg 1995;222:327-338.[Medline]
- Albert W., Kiekbusch S., Köller K., Hetzer R. Quality of life with ventricular assist devices. In: Hetzer R., Hennig E., Loebe M., eds. Mechanical circulatory support. Darmstadt: Springer and Steinkopff, 1997:191-205.
- Siegenthaler M.P., Martin J., Frazier O.H., Beyersdorf F. Implantation of the permanent Jarvik-2000 left-ventricular-assist-device: surgical technique. Eur J Cardio-thorac Surg 2002;21:546-548.[Abstract/Free Full Text]
- Rose A.G., Park S.J., Bank A.J., Miller L.W. Partial aortic valve fusion induced by left ventricular assist device. Ann Thorac Surg 2000;70:1270-1274.[Abstract/Free Full Text]
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Abstract
Introduction
