Ann Thorac Surg 2000;69:1964-1965
© 2000 The Society of Thoracic Surgeons
How to do it
Simple method for direct cannulation of ascending aortic aneurysms
Dan Lindblom, MD, PhDa,
Göran Källner, MD, PhDa,
Anders Alb
ge, MDa,
Jan van der Linden, MD, PhDa
a Department of Cardiothoracic Surgery and Anesthesiology, Karolinska Institutet at Huddinge University Hospital, Stockholm, Sweden
Address reprint requests to Dr Lindblom, Department of Cardiothoracic Surgery and Anesthesiology, Karolinska Institutet at Huddinge University Hospital, S-141 86 Stockholm, Sweden
e-mail: dan.lindblom{at}thsurg.hs.sll.se
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Abstract
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A simple method for direct cannulation of aneurysms of the ascending aorta is described. It avoids the need for femoral artery cannulation and offers an easy route for retrograde cerebral perfusion during deep hypothermic circulatory arrest.
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Introduction
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Arterial inflow during cardiopulmonary bypass is routinely accomplished by cannulation of the distal ascending aorta. For surgery on the ascending aorta or aortic arch, femoral artery cannulation is usually recommended. Femoral cannulation can be difficult or impossible in the presence of ileo-femoral arteriosclerosis. Also, retrograde femoral perfusion might cause arterial injury and dissection, and can be a cause of cerebral embolization of atherosclerotic material from the descending aorta [1]. The groin is also an area of extensive bacterial colonization [2] that is best avoided, especially in patients with synthetic graft replacement of the aorta. We present a method of direct cannulation of the ascending aortic aneurysm that is simple and safe and also offers an easy route for retrograde cerebral perfusion (RCP) during deep hypothermic circulatory arrest (DHCA).
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Technique
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The heart is exposed through a midline sternotomy and the pericardium is opened and tacked to the edges of the wound. The right atrium is cannulated with a two-stage cannula.
Epiaortic scanning of the ascending aortic aneurysm is performed with a compact, portable, ultrasound scanner optimized for vascular imaging and specifically configured for needle guidance for percutaneous vascular access (Site-Rite II, 7.5 MHz; Dymax Corporation, Pittsburgh, PA). This scanner with a hard stand-off makes it particularly suitable to detect areas of the anterior wall devoid of atherosclerotic changes [3]. Such an area is selected and purse-stringed.
A 0.9-mm guidewire is introduced through a needle placed inside the purse-string and its position in the descending aorta is verified by transesophageal echocardiography (TEE). At this point, the perfusionist starts to drain blood from the right atrial cannula into the reservoir until the systolic arterial pressure drops below 75 mm Hg. The aneurysm is cannulated with a No. 20 wire-inforced plastic cannula (elongated one-piece arterial cannula, No. 77420; Medtronic DLP, Grand Rapids, MI) over the guidewire. The tip of the cannula is positioned in the descending aorta (again during TEE control). The cannula is connected to the arterial line from the heart-lung machine and perfusion and cooling is commenced. Cannulas are placed in the coronary sinus and right superior pulmonary vein for cardioplegia and left ventricular decompression, respectively.
If RCP during DHCA is planned, the superior vena cava (SVC) is also dissected, encircled with a tape and prepared for cannulation with a purse-string suture. If indicated, coronary bypass grafts can be anastomosed during the cooling period and with ventricular fibrillation. pH-stat is used during cooling to promote cerebral cooling.
When the hypothermic target temperature (16°C) is reached and the venous saturation in the jugular bulb is approximately 100%, arterial inflow is stopped and the patient is exsanguinated into the reservoir. With the patient in the Trendelenburg position and with carbon dioxide flooding the pericardial cavity, the arterial cannula is removed from the aneurysm and inserted into the SVC. RCP is initiated and the flow is adjusted to keep the pressure in the jugular bulb at 25 mm Hg.
The aneurysm is resected, including the cannulation site, and an appropriately sized Dacron graft is anastomosed to the aortic arch. The arterial cannula is removed from the SVC and inserted into an incision in the distal part of the graft, which is then deaired, and clamped central to the cannula. Antegrade perfusion through the cannulated graft is started and the patient is rewarmed. Aortic valve replacement or repair, if indicated, is performed before anastomosing the graft to the aortic root, and coronary bypass grafts are connected to the graft before unclamping.
The patient is then weaned from the heart-lung machine. As there is often some bleeding from the cannulation site on the graft, it is prudent to decannulate the graft before the right atrium for easier transfusion.
We have used this technique in 3 patients between May and June 1999. Patient data are presented in Table 1. Patient 1 was morbidly obese (body mass index 45.2) with advanced dermatologic changes in both groins, making femoral cannulation unattractive, and her condition inspired us to use this technique. All patients survived surgery without neurological or other complications.
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Comment
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The described technique eliminates the need for dissection of the femoral artery and might be of value in reducing the bacterial contamination of mediastinum. Furthermore, it avoids retrograde perfusion of the descending aorta, thereby minimizing the risk of embolization of atherosclerotic material from the descending aorta into the arch vessels. A similar technique has been described by Westaby and Katsumata for patients undergoing replacement of the descending aorta and for patients undergoing total aortic replacement, but without the additional benefit of RCP [1].
Direct cannulation of aortic aneurysms has probably been avoided because of fear of rupture during cannulation. By cannulating the aneurysm in an area examined by epiaortic scanning and during a period of induced hypotension, it is our experience that this is a safe procedure.
We find this technique reliable and also intend to use it in patients with chronic dissections, provided that correct placement of the guidewire can be ascertained by intraoperative TEE. However, we would hesitate to use this method in patients with acute dissections even if the femoral arteries are inaccessible (because of dissection or occlusive disease) and would in such cases prefer to cannulate the axillary or subclavian arteries or the left ventricular apex as proposed by Robicsek [4].
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References
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Westaby S., Katsumata T. Proximal aortic perfusion for complex arch and descending aortic disease. J Thorac Cardiovasc Surg 1998;115:162-167.[Abstract/Free Full Text]
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Chesham J.S., Platt D.J. Patterns of wound colonisation in patients with peripheral vascular disease. J Infect 1987;15:21-26.[Medline]
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Van der Linden J., Bengtsson L., Lindblom D. Epiaortic scanning of the ascending aorta identifies atherosclerotic plaques and changes surgical practice during CABG?. Br J Anaesth 1996;76(Suppl 1):41.
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Robicsek F. Apical aortic cannulation. Ann Thorac Surg 1991;51:330-332.[Abstract]
Accepted for publication January 3, 2000.
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Abstract
Introduction
