| Arterial switch operation | |
|---|---|
 An 8-day-old right after the Jatene procedure | |
| Other names | Jatene procedure |
| ICD-9-CM | 35.84 |
Arterial switch operation (ASO),arterial switch, orJatene procedure is anopen heartsurgical procedure used to correctdextro-transposition of the great arteries (d-TGA).[1][2]
Its development waspioneered byCanadiancardiac surgeonWilliam Mustard and it was named forBrazilian cardiac surgeonAdib Jatene, who was the first to use it successfully. It was the first method of d-TGA repair to be attempted, but the last to be put into regular use because oftechnological limitations at the time of itsconception.
Use of the arterial switch ishistorically preceded by twoatrial switch methods: theSenning andMustard procedures.[3]
The atrial switch, which was an attempt to correct the physiology of transposition, had significant shortcomings that the arterial switch improved upon, in particular a reduced kinking of thecoronary arteries when combined with theLeCompte maneuver. The end result is that the aorta is repositioned behind the pulmonary arteries, functionally lengthening it and causing less angulation at the coronary origins.[4]
The Jatene procedure is ideally performed during the second week of life, before theleft ventricle adjusts to the lowerpulmonarypressure and is therefore unable to support thesystemic circulation.[5] In the event ofsepsis or delayeddiagnosis, a combination ofpulmonary artery banding (PAB) andshunt construction may be used to increase the left ventricular mass sufficiently to make an arterial switch possible later ininfancy.[6]
The success of ASO procedure is largely dependent on the facilities available, the skill and experience of the surgeon, and the general health of thepatient. Under preferable conditions, theintra-operative andpost-operative success rate is 90% or more, with a comparable survival rate after 5 years.[7] Approximately 10% of arterial switch recipients develop residual pulmonarystenosis post-operatively, which can lead toright heartfailure if left untreated;[8] treatment usually involvesendovascular stenting and/orxenograft patching.[7]
If the procedure is anticipated far enough in advance (withprenatal diagnosis, for example), and the individual'sblood type is known, a family member with a compatibleblood type maydonate some or all of the blood needed fortransfusion during the use of aheart-lung machine (HLM). The patient'smother is normally unable to donate blood for the transfusion, as she will not be able to donate blood duringpregnancy (due to the needs of thefetus) or for a few weeks after givingbirth (due toblood loss), and the process of collecting a sufficient amount of blood may take several weeks to a few months. However, in cases where the individual has been diagnosed but surgery must be delayed, maternal (or evenautologous, in certain cases) blood donation may be possible, as long as the mother has a compatible blood type. In most cases, though, the patient receives a donation from ablood bank. A blood transfusion is necessary for the arterial switch because the HLM needs its "circulation" filled with blood and an infant does not have enough blood on their own to do this (in most cases, an adult would not require blood transfusion).[citation needed]
The patient will require a number ofimaging procedures in order to determine the individualanatomy of the great arteries and, most importantly, thecoronary arteries. These may includeangiography,magnetic resonance imaging (MRI), and/orcomputed tomography (CT scan). The coronary arteries are carefully mapped out in order to avoid unexpected intra-operative complications in transferring them from the native aorta to the neo-aorta.[citation needed]
As with any procedure requiring general anaesthesia, arterial switch recipients will need tofast for several hours prior to the surgery to avoid the risk of aspiration of vomitus during the induction of anesthesia.[citation needed]
As the patient is anesthetized, they may receive the followingdrugs, which continue as necessary throughout the procedure:
The heart is accessed viamedian sternotomy and itspericardium is removed so the coronary and great arteries can be seen. Theductus arteriosus and main rightpulmonary artery, up to and including the first branches in thehilum of the rightlung, are separated from the surrounding supportivetissue to allow mobility of thevessels. Cardiopulmonary bypass is then initiated and thebody iscooled to prevent thebrain damage otherwise associated with low blood flow during the surgery.
While the patient is cooling, the ductus arteriosus isligated at both the aortic and pulmonaryostia, thentransected at its center; the main left pulmonary artery including its first branches in the lefthilum, is separated from surrounding connective tissue. When the patient is fully cooled, the ascending aorta is clamped andcardioplegia is achieved by delivering cold blood to the heart via the ascending aorta (below thecross clamp). The aorta and pulmonary arteries aresurgically cut. The vessels are again examined, and the pulmonary root is inspected forleft ventricular outflow tract obstruction. If aventricular septal defect is present, it is also repaired via theaortic orpulmonary valve.
The great arteries are usually arranged using theLeCompte maneuver, with the aortic cross clamp positioned to hold the pulmonary arteryanterior to the ascending aorta. On imaging, the pulmonary arteries will classically have the appearance of being draped over the aorta. Sometimes, however, patient anatomy prevents this and the aorta great vessels are kept in the non-anatomic 'anterior aorta' arrangement. The coronary arteriesinfundibular branches and the aortic root extending thesinus of Valsalva are then surgically cut off the native aorta and transplanted onto the pulmonary root to make a neo-aorta.
The bypass machine is then turned off, anincision is made in the right atrium, through which thecongenital orpalliativeatrial septal defect is repaired. In septal defects where aRashkind balloon atrial septostomy was used, the ASD should be able to be closed with sutures, but cases involving large congenital atrial septal defects orBlalock-Hanlon atrial septectomy, a patch can be used.
If there is aventricular septal defect which has not yet been repaired, this is also fixed through the atrial incision andtricuspid valve, again using sutures for a small defect or a patch for a large defect.
When the septal defects have been repaired and the atrial incision is closed, the patient is again placed on cardiopulmonary pass. The left ventricle is then vented and the cross clamp removed from the aorta, enabling full-flow to be re-established and rewarming to begin. At this point the patient will receive an additional dose of Regitine to keepblood pressure under control. The previously harvested pericardium is then used to patch the coronaryexplantation sites, and to extend and widen the neo-pulmonary root, which allows the pulmonary artery to be anastamosed without residua tension; the pulmonary artery is then transplanted to the neo-pulmonary root.
The patient is fitted withchest tubes, temporarypacemaker leads, andventilated beforeweaning from the HLM is begun.
Therib cage is relaxed and the external surgicalwound is bandaged, but thesternum and chest incision are left open to provide extra room in thepleural cavity, allowing the heart room to swell and preventing pressure caused bypleural effusion.
The sternum and chest can usually be closed within a few days; however, the chest tubes, pacemaker, ventilator, and drugs may still be required after this time. The patient will continue to fast for up to a few days, andbreastmilk orinfant formula can then be gradually introduced vianasogastric tube (NG tube); the primarygoal after a successful arterial switch, and beforehospital discharge, is for theinfant to gain back the weight they have lost and continue to gain weight at a normal or near-normal rate.[citation needed]
ScottishpathologistMatthew Baillie first describedTGA in 1797, presumably as aposthumous diagnosis.[9] Without surgical correction, preoperative mortality in the neonate is approximately 30% within the first week of life and up to 90% within the first year;[7] the survivors would have been those with one or moreconcomitantintracardiacshunts (ASD,patent ductus arteriosus (PDA),patent foramen ovale (PFO), and/or VSD), and are unlikely to have survived pastadolescence.[10]
In 1950,American surgeonsAlfred Blalock andC. Rollins Hanlon introduced theBlalock-Hanlon atrial septectomy, which was then routinely used to palliate patients.[11] This would have effectively reduced early mortality rates, particularly in cases with no concomitant shunts, but is unlikely to have reduced late mortality rates.
Mustard first conceived of, and attempted, the anatomical repair (arterial switch) for d-TGA in the early 1950s. His few attempts were unsuccessful due to technical difficulties posed by thetranslocation of the coronary arteries, and the idea was abandoned.[12]
Swedish cardiac surgeonÅke Senning described the first corrective surgery for d-TGA (theSenning procedure) in 1959, which involved using theatrial septum to create anintratrialbaffle that redirectedbloodflow at theatrial level; Senning yielded a high success rate using this procedure, significantly lowering both early and late mortality rates.[13]
Due to the technical complexity of the Senning procedure, others could not duplicate his success rate; in response, Mustard developed a simpler alternative method (theMustard procedure) in 1964, which involved constructing a baffle fromautologouspericardium orsynthetic material, such as Dacron.[14] This procedure yielded early and late mortality rates comparable to the Senning procedure; however, alate morbidity rate was eventually discovered in relation to the use of synthetic graft material, which does not grow with the recipient and eventually causesobstruction.[15]
In 1966, American surgeonsWilliam Rashkind andWilliam Miller transformed the palliation of d-TGA patients with the innovativeRashkind balloon atrial septostomy, which, unlike thethoracotomy required by a septectomy, is performed through theminimally invasive surgical technique ofcardiac catheterization.[16]
The late morbidity rate is high in atrial switch, combined with advances inmicrovascular surgery, created a renewed interest in Mustard's original concept of an arterial switch procedure. The first successful arterial switch was performed on a forty-two-day-old d-TGA + VSD infant by Jatene in 1975.[17] Egyptian cardiac surgeonMagdi Yacoub was subsequently successful in treating TGA with AN intactinterventricular septum when preceded by pulmonary artery banding and systemic-to-pulmonary shunt palliation.[6][18] Austrian surgeonB. Eber was the first to recount a small series of successful arterial switch procedures, and the first large successful series was reported byGuatemalan surgeonAldo R. Casteneda.[19] In the postoperative period, increased incidence and degree of supravalvular pulmonary stenosis.[20] Eliminating the pericardial patch for pulmonary artery reconstruction and using a direct connection reduced the incidence of this complication.[8][21]
By 1991, the arterial switch had become the procedure of choice, and it remains the standard modern procedure for d-TGA repair.[7]
As long-term results of arterial switch are being reported, newer sets of potential surgical problems are becoming evident. Progressive neo-aortic dilation (pulmonary valve at birth) has been observed. However, this dilation does not necessarily translate into aortic regurgitation (AR) and need for surgery in all patients. Older age at time of ASO, presence of ventricular septal defect, and previous PA banding have been found to be risk factors for AR.[4][22]supravalvular pulmonary stenosis was commonly observed in the postoperative period. A direct connection of the pulmonary artery reduced the incidence of this complication[23][24]
The world's smallest infant to survive an arterial switch was Jerrick De Leon, born 13 weeks premature. At the time of the operation on February 6, 2005, he weighed just over 1.5 pounds (700 grams).[25]
