Ann Thorac Surg 2007;84:1403-1404
© 2007 The Society of Thoracic Surgeons
How To Do It
Aortic Arch Repair and Cold-Reactive Agglutinins: What to Do?
Aristotelis Panos, MD*,
Nicolas Murith, MD,
Patrick O. Myers, MD,
Afksendyios Kalangos, MD
Clinic for Cardiovascular Surgery, University Hospital of Geneva, Geneva, Switzerland
Accepted for publication December 13, 2006.
* Address correspondence to Dr Panos, Clinic for Cardiac Surgery, University Hospital of Geneva, 24, Rue Micheli-du-Crest, 1211 Geneva 14, Switzerland (Email: a.panos{at}bluewin.ch).
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Abstract
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We describe a modified perfusion technique for aortic arch repair under mild hypothermia and continuous cerebral and systemic perfusion.
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Introduction
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Cold-reactive agglutinins are found in sera of healthy persons but rarely become clinically important because most agglutinins exert their greatest reactivity at low temperatures. Their incidence in the open heart operation population is estimated to be 0.8% [1]. In these patients, cardiovascular operations requiring hypothermia can cause increased blood viscosity and sludging of red blood cells and may lead to hemolysis, renal failure, and myocardial or cerebral infarction.
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Technique
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A 75-year-old patient, previously operated for type A aortic dissection 13 years earlier with replacement of the ascending aorta, was admitted for reoperation after an important dilatation developed of 58 mm of the aortic arch and of 60 mm of the proximal portion of the descending aorta. The false lumen was not patent anymore. The patient was also discovered to have a high titre of cold-reactive agglutinins with a reactive temperature of 27°C.
For the arterial perfusion of the lower body, we used a single-stage venous 37F Disposable Pressure Display Set (DLP) cannula (DLP 91037; Medtronic, Minneapolis, Minnesota) with an inflatable cuff on its extremity. The silicone occlusive balloon can be inflated with saline to create an aortic tape. The maximum safe diameter of the balloon is 6.35 cm, with a tested pressure of 60 mm Hg.
The patient gave his informed consent for the operation. Before starting the operation, we prepared the cardiopulmonary bypass (CPB) lines and cannulas. On the arterial line, we mounted a Y connector to split the flow into two lines. One was connected to the axillary artery 24F cannula (Terumo, Tokyo, Japan) and the other to the Medtronic DLP cannula. The redo operation was conducted through midline sternotomy, and CPB was initiated through the right axillary artery and the right femoral vein. The body was cooled to a rectal temperature of 30°C. During cooling, the aortic arch and neck vessels were prepared for control. The ascending aortic graft was cross clamped, and warm blood cardioplegia was delivered in an antegrade manner to achieve cardiac arrest. At 30°C, the flow rate of the CPB was decreased. The three neck vessels were clamped individually with atraumatic neonatal clamps, and the aortic cross clamp was released.
During this period of systemic circulatory arrest, the brain was continuously perfused through the right axillary artery to a flow rate of 12 mL · kg–1 · min–1 and a mean arterial pressure of 60 mm Hg. Perioperative blood flow through the middle cerebral arteries was monitored continuously with bilateral transcranial Doppler (Multigon, Yonkers, NY). The aortic arch was incised and the pathologic tissues transected. At this moment, we introduced the arterial line connected to the Medtronic DLP cannula through the new Dacron graft (Boston Scientific, Natick, MA) and then within the descending aorta (Fig 1). The ballon was then inflated to achieve a blood-proof occlusion of the aorta, and at the same time, the blood flow increased progressively to the normal systemic rate. The lower body circulatory arrest was 8 minutes.
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Fig 1. Schematic representation of the operating field with the arterial line connected to the Medtronic Disposable Pressure Display Set (DLP) cannula through the Dacron graft (Boston Scientific, Natick, MA) and then within the descending aorta. The arrows indicate the perfusion flow through the right axillary artery and the DLP cannula.
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The gelatin-coated Dacron tube graft (32 mm diameter) was anastomosed distally to the descending aorta in an open way with 3-0 polypropylene sutures while rewarming was initiated. After the completion of the distal anastomosis, the neck vessels were anastomosed to the same Dacron graft in an islet fashion with continuous 3-0 polypropylene sutures. The blood flow was then decreased again, the balloon deflated, the cannula retrieved, and the graft deaired. A clamp was applied just proximal to the last anastomosis, and the systemic blood flow resumed only through the right axillary cannula. The proximal anastomosis was performed between the previous graft and the new graft with continuous sutures of 3-0 polypropylene. The clamp on the graft was then released. The operation was completed in the usual way, after a lower body circulatory arrest of 8 minutes, an aortic cross-clamp time of 55 minutes, and a total CPB time of 130 minutes. The postoperative course was uneventful, and the patient was discharged 8 days later.
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Comment
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Although the incidence of cold-reactive agglutinins is low, when present, these antibodies may seriously complicate the outcome of patients undergoing heart operations. Patients with high temperature cold agglutinins who undergo aortic arch repair under hypothermia and systemic circulatory arrest may present with microvascular occlusion, hemolysis, complement fixation, renal and hepatic insufficiency, cerebral insult, and myocardial infarction [2]. To avoid these conditions, the core hypothermia should not reach the reactive thermal amplitude of the specific cold agglutinin or its titre should be reduced, either by standard hemodilution techniques for CPB or by plasmapheresis. In the past, preoperative plasma exchange was the preferred method [3]. Lee and associates [4] described a total wash-out method, which is theoretically attractive but has the disadvantage of massive transfusions. Actually, the normothermic operation with warm blood cardioplegia prevents activation of these proteins while at the same time provides excellent myocardial protection for all patients, requiring no cardiotomy. However, for patients for whom deep hypothermia and circulatory arrest are required, as for patients operated on for arch replacement, preoperative plasmapheresis followed by hypothermia above the thermal amplitude and low-flow CPB may be an alternative [1].
We propose a method of mild hypothermia (30°C) associated with continuous perfusion of the brain and of the lower body, with only a very limited circulatory arrest (8 minutes) of the lower body. The duration of the circulatory arrest in the lower body corresponds to the necessary time for the resection of the aortic tissues, positioning of the DLP cannula in the descending aorta, and inflation of the occlusion balloon. With this method, both the brain and the lower body are continuously perfused at a mild hypothermia. In this way, we transform an arch repair operation to a standard CPB heart operation. The peroperative bilateral transcranial Doppler (Multigon) monitoring of the blood flow through the middle cerebral artery is of capital importance. If an asymmetry in the blood flow between both cerebral arteries is noted, selective cannulation of the left common carotid must be performed.
As for the 8-minute limited duration of the circulatory arrest in the lower body, it is safe for the spinal cord and splanchnic organs at this temperature. According to previous studies [5], at normothermia, 35 to 40 minutes of safe duration of circulatory arrest is expected for the liver; this safe period extends to 30 to 90 minutes for the warm ischemia in the kidney [6]. As for the spinal cord, a safe period of as long as 20 minutes was reported by Kirklin and Barrat-Boyes [5] in case of aortic cross-clamping at normothermia. In our patient, the duration of this cold agglutinin is well below these limits. In addition, with the use of moderate hypothermia, we are avoiding the systemic deleterious effects of deep hypothermia, especially on platelet activation pathways and on the enzymatic activity of clotting factors, decreasing bleeding. The occlusion balloon was very efficient in obtaining a blood-proof field to perform an open type anastomosis and at the same time obtaining a full flow antegrade perfusion of the lower body. Overdistension of the aorta when inflating the balloon is precluded by the presence of a small and easily distensible security balloon just after the inflation tip. Times of CPB are also shorter with this method because the duration of rewarming is less, and because rewarming begins just after the completion of the distal anastomosis even before the anastomosis of the neck vessels.
This technique is reported in the setting of a patient with cold-reactive agglutinins undergoing aortic arch repair under mild hypothermia without circulatory arrest. It has the potential to be applicable generally in the surgery of aortic arch repair after further evaluation.
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References
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- Agarwal S, Ghosh P, Gupta D. Cardiac surgery and cold-reactive proteins Ann Thorac Surg 1995;60:1143-1150.[Abstract/Free Full Text]
- Foerster J. Autoimmune haemolytic anemiasIn: Lee GR, Bithell TC, Foerster J, Athens JW, Lukens JN, editors. Wintrobe’s clinical haematology. Philadelphia: Lea & Febiger; 1993. pp. 1170-1196.
- Shahian DM, Wallach SR, Bern MM. Open heart surgery in patients with cold reactive proteins Surg Clin North Am 1985;65:315-322.[Medline]
- Lee MC, Chang CH, Heish MJ. Use of a total wash-out method in an open heart operation Ann Thorac Surg 1989;47:57-58.[Abstract]
- Kirklin J, Barrat-Boyes B. Hypothermia and total circulatory arrest2nd ed.. Cardiac surgery. 74. New York, NY: Churchill Livingstone; 1993. pp. 1712-1713.
- Laven B, Orvietto M, Chuang M. Renal tolerance to prolonged warm ischemia time in a laparoscopic versus open surgery porcine model J Urol 2004;172:2471-2474.[Medline]
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Abstract
Introduction
