|
|
||||||||
Ann Thorac Surg 2001;72:1615-1620
© 2001 The Society of Thoracic Surgeons
a Division of Cardiovascular Surgery, The Montréal Childrens Hospital, McGill University Health Center, Montréal, Québec, Canada
b Division of Anesthesia, The Montréal Childrens Hospital, McGill University Health Center, Montréal, Québec, Canada
* Address reprint requests to Dr Tchervenkov, Department of Cardiovascular Surgery, Room C-829, The Montreal Childrens Hospital, McGill University Health Center, 2300 Tupper St, Montréal, QB, H3H 1P3, Canada
e-mail: christo.tchervenkov{at}muhc.mcgill.ca
Presented at the Poster Session of the Thirty-seventh Annual Meeting of The Society of Thoracic Surgeons, New Orleans, LA, Jan 2931, 2001.
| Abstract |
|---|
|
|
|---|
Methods. Eighteen patients, with a median age of 11 days (range 1 to 85 days) and a mean weight of 3.2 ± 0.8 kg, underwent aortic arch reconstruction with LFCP. Seven had biventricular repairs with arch reconstruction, 9 underwent the Norwood operation and 2 had isolated arch repairs. In 1 Norwood and 7 biventricular repair patients, LFCP was maintained by advancing the cannula from the distal ascending aorta into the innominate artery. In 8 of 9 Norwood patients, LFCP was maintained by directing the arterial cannula into the pulmonary artery confluence and perfusing the innominate artery through the right modified BlalockTaussig shunt fully constructed before cannulation for cardiopulmonary bypass. In 2 patients requiring isolated arch reconstruction, the ascending aorta was cannulated and the cross-clamp was applied just distal to the innominate artery.
Results. LFCP was maintained at 0.6 ± 0.2 L · min-1 · m-2 for 41.0 ± 13.9 minutes at 18.5°C ± 1.1°C. In 10 of the 18 patients, blood pressure during LFCP was 15 ± 8 mm Hg remote from the innominate artery (left radial, umbilical or femoral arteries). In 8 of the 18 patients, right radial pressure during LFCP was 24 ± 10 mm Hg. The mean mixed-venous saturation was 79.8% ± 10% during LFCP. Two patients had preoperative seizures, whereas none had seizures postoperatively. One patient died.
Conclusions. Neonatal aortic arch reconstruction is possible without circulatory arrest or direct arch vessel cannulation. These techniques maintained adequate mixed-venous oxygen saturations with no associated adverse neurologic outcomes.
| Introduction |
|---|
|
|
|---|
| Patients and methods |
|---|
|
|
|---|
Cardiac malformations
The cardiac malformations with their corresponding aortic arch pathology and surgical repairs are summarized in Table 1.
|
We use criteria suggested by Karl and associates [13] to define aortic arch hypoplasia requiring intervention. If the transverse aortic arch diameter as measured on echocardiography is less than the patients weight in kilograms + 1, the arch is considered hypoplastic. For example, in a 3-kg infant, if the aortic arch is less than 4 mm (ie, 3 + 1), we consider it hypoplastic and would enlarge the arch surgically. We believe that although residual aortic arch hypoplasia after coarctation repair may be well tolerated by an otherwise normal heart, this deformity will present a significant anatomic afterload and will not be tolerated by a heart undergoing complex intracardiac repair with a significant duration of myocardial ischemia and cardiopulmonary bypass.
Surgical techniques
We have used three techniques for LFCP during aortic arch reconstruction, depending on its extent and the nature of the intracardiac repair. These techniques completely avoid the use of DHCA and direct arch vessel cannulation. Continuous LFCP under deep hypothermia is maintained through the innominate artery. Each surgical technique for LFCP is described below.
Technique 1
In 7 patients undergoing biventricular repair and in 1 patient the Norwood operation, the ascending aorta was large enough to be cannulated (Fig 1). After median sternotomy and systemic heparinization, a flexible aortic cannula (8F, BioMedicus, Medtronic, Minneapolis, MN) was placed in the right side of the distal ascending aorta, approximately 5 mm proximal to the origin of the innominate artery. Standard bicaval cannulation was performed for the venous drainage and cardiopulmonary bypass (CPB) was established. The patent ductus arteriosus (PDA) was immediately ligated and the patient was cooled to 18°C. Intracardiac repair was performed during cooling. The aortic cannula was then advanced into the innominate artery without taking it out and was snared in place. The left subclavian and left common carotid arteries were also snared and a vascular clamp was applied to the upper descending thoracic aorta to isolate the aortic arch. The entire aortic arch was then reconstructed by the technique of pulmonary homograft patch aortoplasty [14], while maintaining LFCP at 0.3 to 0.8 L · min-1 · m-2 through the innominate artery. Releasing the clamp from the descending aorta or the snares from the left carotid or subclavian arteries during LFCP resulted in brisk back-bleeding, suggesting significant blood flow to the brain and the lower body. After removing air from the ascending aorta by releasing the distal clamp, the aortic cannula was pulled back from the innominate artery into the ascending aorta. The head vessels were unsnared, full perfusion was reestablished, and the patient was rewarmed and weaned from cardiopulmonary bypass.
|
|
A flexible arterial cannula (8F, BioMedicus, Medtronic) was placed in the proximal third of the PDA and directed distally toward the descending aorta. Standard right-angled cannulas were placed in the inferior and superior vena cavas for venous drainage. The PDA was then snared proximal to the arterial cannulation and the MBTS was clamped just before initiating full-flow CPB. The patients were cooled systemically to
18°C. During cooling, with the heart beating, the main PA was transected just before its bifurcation and the distal end was closed with a pulmonary homograft patch. After the patient reached deep hypothermia, the arterial cannula was redirected into the PA confluence, the PDA snare was moved distally, and both branch PAs were snared. The MBTS was opened and LFCP was initiated retrogradely through the innominate artery. The proximal innominate, the left carotid and the left subclavian arteries were snared and the descending aorta was clamped to allow isolation of the aortic arch. This technique completely avoided DHCA during the completion of the Norwood operation [6]. The arterial cannula was then transferred to the neoaorta, followed by clamping of the MBTS and removal of the snares from the head vessels and of the distal aortic clamp. The proximal PDA was suture-ligated and the snares from the branch pulmonary arteries were also removed. The patients were rewarmed and weaned from CPB.
Technique 3
Two patients required isolated reconstruction of the distal aortic arch (Fig 3). One had an aortic arch aneurysm associated with PA aneurysms, whereas the other had recurrent arch obstruction after two-ventricle repair for hypoplastic left heart complex. In these cases, aortic arch reconstruction was performed by cannulation of the ascending aorta and systemic cooling to a nasopharyngeal temperature of 19°C. While the patient was on CPB, a clamp was applied to the proximal aortic arch just distal to the innominate artery. A second clamp was applied to the upper descending thoracic aorta while snaring the left carotid and left subclavian arteries. Cerebral perfusion was thus maintained through the arterial cannula perfusing ascending aorta and the innominate artery. In both cases, the aortic arch was reconstructed with a pulmonary homograft patch aortoplasty.
|
| Results |
|---|
|
|
|---|
Mixed-venous oxygen saturation
Oxygen saturation was measured continuously in the venous cannula with an oximeter attached to the venous line of the CPB circuit. Data were available for 14 of the 18 patients. The lowest mixed-venous oxygen saturation during the period of LFCP was 79.8% ± 10%.
Clinical outcome
One patient with complete atrioventricular canal, secundum atrial septal defect, hypoplastic left ventricle, aortic arch hypoplasia, and coarctation died of low output state on postoperative day 1 after a Norwood operation. Although 2 patients experienced preoperative seizures, no patients had seizures or other adverse neurologic events postoperatively. No patients were discharged from the hospital on antiseizure medication.
| Comment |
|---|
|
|
|---|
Asou and associates [9] described two techniques of selective cerebral perfusion during aortic arch repair in neonates undergoing the Norwood operation for hypoplastic left heart syndrome. The first technique involved perfusion of the innominate artery through an arterial cannula attached to the open end of a modified MBTS, after construction of the proximal anastomosis. The second technique involved direct cannulation of the innominate artery with a thin-walled metal cannula. Ishino and associates [11] have recently described their techniques for single-stage repair of aortic coarctation with ventricular septal defect using techniques for isolated cerebral and myocardial perfusion. One approach perfused the innominate artery from an arterial cannula inserted into the open end of a temporary polytetrafluoroethylene graft sewn to the innominate artery. Another approach used by this group was similar to our technique number 3 with a clamp placed just distal to the innominate artery while the distal arch was reconstructed. McElhinney and associates [12] maintained continuous upper body perfusion while performing a modified DamusKayeStansel procedure by cannulating the base of the innominate artery rather than using the MBTS. Others have cannulated both the MBTS and the descending thoracic aorta above the diaphragm, through a sternotomy approach to perfuse the upper and lower body during reconstruction of the aortic arch [10].
Pigula and colleagues [7] have also used an arterial cannula inserted into the open end of the MBTS to allow LFCP during reconstruction of the aortic arch. Although their technique was similar to those we described above, they used near infrared spectroscopy to characterize the cerebral blood volume and cerebral oxygen saturations during periods of LFCP. They found that a flow of 20 mL · kg-1 · min-1 was adequate in restoring cerebral blood volume and oxygen saturation at 18°C.
At The Montreal Childrens Hospital we have been able to consistently apply three techniques of LFCP, all of which avoid direct arch vessel cannulation and DHCA, for a wide variety of cardiac malformations requiring concomitant aortic arch reconstruction. When the ascending aorta is large enough to cannulate directly, we have used a technique of continuous LFCP through an arterial cannula advanced into the innominate artery (technique 1). This technique is straightforward and reproducible and the cannula has not impeded the extent to which we are able to augment the aortic arch. In a most challenging situation, such as the Norwood operation, we have developed a technique of retrograde flow through the MBTS into the innominate artery to maintain LFCP (technique 2) [6]. The MBTS is fully constructed before cannulation for CPB. This technique has reduced CPB time, avoided DHCA completely, and prevented any tension or inadvertent traction on the proximal end of the MBTS. The long, flexible arterial cannula inserted into the PDA has not impeded exposure of the arch during reconstruction. Using these techniques, we have been able to avoid both direct cannulation of the innominate artery and the construction of temporary grafts, each of which carries the risk of causing arterial stenoses in the future. Although we have been able to use these techniques of LFCP in a wide variety of cardiac malformations, we have not yet had the opportunity to use them in patients with interrupted aortic arch. The frequently diminutive ascending aorta, the use of two arterial cannulas, and the necessity for a direct anastomosis over a significant distance between the descending aorta and the small ascending aorta may present a particular technical challenge for any technique of LFCP.
During periods of LFCP, we have used flows of 0.3 to 1.0 L · min-1 · m-2. When converted to the units used by Pigula and colleagues [7], our low-flow perfusion was maintained between 18 to 76 mL · kg-1 · min-1 (mean = 44 mL · kg-1 · min-1), suggesting adequate cerebral circulatory support. In our study, the lowest oxygen saturation of the blood returning to the venous side of the CPB circuit was nearly 80%. This blood was drained from both the inferior and superior vena cavas and suggests adequate oxygen delivery to upper and lower body during LFCP. It may have been useful to separate the venous cannulas to measure the difference in the venous saturations between the inferior and superior vena cavas during LFCP and we intend to do this in the future. We have observed that LFCP through the innominate artery results in a significant amount of blood flow to the lower body through collaterals. Although this is only a subjective observation, we have found that removing the cross-clamp on the descending aorta during our arch reconstruction resulted in flooding of the field immediately with blood, with the sole source of perfusion being the innominate artery. Pigula and associates [15] recently quantified the significant circulatory support that regional cerebral perfusion provides below the diaphragm.
In summary, neonatal aortic arch reconstruction can be performed on a consistent basis using several techniques of LFCP with a low morbidity and mortality, avoiding DHCA or direct arch vessel cannulation. Continuous LFCP maintained adequate mixed-venous oxygen saturations with no associated adverse neurologic events. These techniques can be applied successfully in a wide variety of intracardiac repairs, including the Norwood operation. Further follow-up and a greater experience are required to determine the long-term impact of these techniques on neurodevelopmental outcomes.
| References |
|---|
|
|
|---|
This article has been cited by other articles:
![]() |
T. Allibhai, R. DiGeronimo, J. Whitin, J. Salazar, T. T.-S. Yu, X. B. Ling, H. Cohen, P. Dixon, and A. Madan Effects of moderate versus deep hypothermic circulatory arrest and selective cerebral perfusion on cerebrospinal fluid proteomic profiles in a piglet model of cardiopulmonary bypass J. Thorac. Cardiovasc. Surg., December 1, 2009; 138(6): 1290 - 1296. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. F Corno and M. Pozzi Safe Innominate Artery Cannulation for Cardiopulmonary Bypass in Neonates Asian Cardiovasc Thorac Ann, December 1, 2007; 15(6): 528 - 530. [Abstract] [Full Text] [PDF] |
||||
![]() |
G. Gargiulo, G. Oppido, E. Angeli, and C. P. Napoleone Neonatal aortic arch surgery MMCTS, July 23, 2007; 2007(0723): 2345. [Abstract] [Full Text] [PDF] |
||||
![]() |
G. Oppido, C. P. Napoleone, S. Turci, B. Davies, G. Frascaroli, S. Martin-Suarez, A. Giardini, and G. Gargiulo Moderately Hypothermic Cardiopulmonary Bypass and Low-Flow Antegrade Selective Cerebral Perfusion for Neonatal Aortic Arch Surgery Ann. Thorac. Surg., December 1, 2006; 82(6): 2233 - 2239. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. Ricci, G. A. Cohen, D. Roebuck, and M. J. Elliott Management of complex tracheo-aortic fistula following neonatal tracheal reconstruction Ann. Thorac. Surg., April 1, 2003; 75(4): 1325 - 1328. [Abstract] [Full Text] [PDF] |
||||
![]() |
W. M. DeCampli, G. Schears, R. Myung, S. Schultz, J. Creed, A. Pastuszko, and D. F. Wilson Tissue oxygen tension during regional low-flow perfusion in neonates J. Thorac. Cardiovasc. Surg., March 1, 2003; 125(3): 472 - 480. [Abstract] [Full Text] [PDF] |
||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| ANN THORAC SURG | ASIAN CARDIOVASC THORAC ANN | EUR J CARDIOTHORAC SURG |
| J THORAC CARDIOVASC SURG | ICVTS | ALL CTSNet JOURNALS |