Avoiding hypoxemia during unifocalization

Avoiding hypoxemia during unifocalization

Ann Thorac Surg 1996;61:715-7 Great credit for this is due to those such as the group at C h i l d r e n ' s Hospital of Philadelphia who have so com...

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Ann Thorac Surg 1996;61:715-7

Great credit for this is due to those such as the group at C h i l d r e n ' s Hospital of Philadelphia who have so comprehensively refined the m a n a g e m e n t of these patients. However, the Fontan p r o c e d u r e is sometimes accompanied by perioperative m o r b i d i t y in the form of generalized edema, celomic effusions, a n d insufficient systemic perfusion. These complications stem from physiology in which all the systemic return is driven t h r o u g h the p u l m o n a r y vascular b e d b y elevated systemic venous pressure. To reduce this morbidity, the concept of partial diversion of systemic venous return from the p u l m o n a r y circulation has been a p p l i e d in the form of a surgically d e s i g n e d residual interatrial communication [3]. This a p p r o a c h has gained some p o p u l a r i t y and is referred to as a " f e n e s t r a t e d " Fontan. A deliberately restrictive, n o n g r o w i n g fenestration in the atrial baffle is d e s i g n e d to be closed at a desirable stage of circulatory adaptation. Expanding further on this principle, Jacobs and N o r w o o d r e p o r t e d a series of Fontan operations with modifications using the exclusion of one or more hepatic veins from the systemic venous channel in 76 patients [1]. Although their patients i n d e e d generally realized a smooth postoperative course with acceptable levels of oxygenation a n d a low incidence of effusive p r o b l e m s (14%), they a c k n o w l e d g e d uncertainty r e g a r d i n g the long-term stability of the degree of desaturation inherent with an obligatory right-to-left shunt. The p r e s e n t case u n d e r scores the n e e d for e x t e n d e d follow-up in this group of patients. In Fontan physiology, any residual venous connection that m a y short-circuit systemic venous return into the p u l m o n a r y venous (oxygenated) atrium creates a potentially progressive right-to-left shunt. Although a certain degree of desaturation is expected with partial hepatic vein exclusion, p r o f o u n d cyanosis should p r o m p t an investigation. The p r e s e n t case illustrates the n e e d to look for a larger shunt such as is seen with hepatic v e n o v e n o u s fistulas. Indeed, the vast intrahepatic sinusoidal vascular b e d m a y make such collateralization an anticipated natural consequence of an excluded hepatic vein. This d e v e l o p m e n t is d i a g n o s e d reliably by angiogr a p h y in the inferior vena cava portion of the cavopulm o n a r y anastomosis with special e m p h a s i s on the liver circulation. In the p r e s e n t case, the intrahepatic fistulous n e t w o r k h a d reached such a capacity that flow from injection in the superior caval portion of the connection was seen s i p h o n e d away from the p u l m o n a r y circulation as well. Severe progressive cyanosis w o u l d be the expected clinical correlate of p u l m o n a r y flow diversion from both venae cavae. The m a g n i t u d e of this right-toleft shunt would not be a p p a r e n t from the typical anglogram obtained by injection in the mid-transatrial channel, without special views of the liver. Therefore, we r e c o m m e n d an inferior vena caval angiogram as part of the diagnostic workup for these patients. This particular complication was previously r e p o r t e d in a short communication by its originator, Lecompte [41. His experience with the exclusion of all major s u p r a h e patic veins led him to advise against any technique that potentially fosters collateralization b e t w e e n avenues of hepatic drainage at different pressures. A l t h o u g h the surgical correction of this acquired shunt can be accomp l i s h e d with relative ease and safety, we too w o u l d © 1996 by The Society of Thoracic Surgeons Published by Elsevier Science lnc

CASE REPORT

MIGNOSAET AL UNIFOCALIZATION

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counsel against this particular modification. W e believe other m o r e discretely fashioned forms of " f e n e s t r a t i o n " ought to be considered in Fontan candidates in w h o m s o m e m e a n s of systemic v e n o u s d e c o m p r e s s i o n is d e e m e d advisable.

References 1. Jacobs M, Norwood WJ. Fontan operation: influence of modifications on morbidity and mortality. Ann Thorac Surg 1994; 58:945-52. 2. Driscoll D, Offord K, Feldt R, et al. Five-to-fifteen year follow-up after Fontan operation. Circulation 1992;85:469-96. 3. Laks H, Pearl JM, Haas GS, et al. Partial Fontan: advantages of an adjustable interatrial communication. Ann Thorac Surg 1991;52:1084-94. 4. Lecompte Y. Subtotal cavopulmonary connection [Letter]. J Thorac Cardiovasc Surg 1992;104:1500.

Avoiding Hypoxemia During Unifocalization Carmelo Mignosa, MD, Juan V. Comas, MD, PhD, Hitoshi Kitayama, MD, a n d Tom R. Karl, MD Victorian Paediatric Cardiac Surgical Unit, Royal Children's Hospital, Melbourne, Australia

An 11-month-old child underwent unifocalization of the major aortopulmonary collateral arteries, but did not tolerate occlusion of both vessels simultaneously. Using a Y-shaped homograft tube, we translocated the vessels sequentially and avoided severe hypoxemia.

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u l m o n a r y atresia with ventricular septal defect and major a o r t o p u l m o n a r y collateral arteries (MAPCAs) is an anatomic entity that usually requires staged surgical m a n a g e m e n t . In the presence of multifocal blood supply the initial surgical goal is to connect as m a n y p u l m o n a r y segments as possible to a central blood s u p p l y (unifocalization). W e p r e s e n t a patient with absent central p u l m o nary arteries who, at the time of unifocalization, did not tolerate M A P C A occlusion because of hypoxemia. Mana g e m e n t strategy is outlined. The patient is an 11-month-old boy with p u l m o n a r y atresia, ventricular septal defect, absent central p u l m o nary arteries, and M A P C A - d e p e n d e n t lung circulation. At 1 m o n t h of age he u n d e r w e n t division of a large left-sided M A P C A from the d e s c e n d i n g aorta, which was the u n i q u e source of blood to the left lung. The M A P C A was connected to the aortic arch using a 4 - m m polytetrafluoroethylene shunt. He was referred to our unit for further staging with a view to complete repair. At this point the a n a t o m y was as shown in Figure 1. In consideration of the age a n d the presence of a stenotic right u p p e r MAPCA, we p l a n n e d a right M A P C A unifocalizaAccepted for publication Aug 4, 1995. Address reprint requests to Dr Karl,VictorianPaediatric Cardiac Surgical Unit, Royal Children's Hospital Flemington Rd, Parkville,Victoria 3052, Australia. 0003-4975/96/$15.00 SSDI 0003-4975(95)00886-1

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CASEREPORT M|GNOSAET AL UN1FOCAL1ZATION

Fig 1. Preoperative aortogram showed two large major aortopulmonary collateral arteries from the descending aorta, comprising the sole blood supply to the right lung.

tion using an aortic homograft tube to create a neopulm o n a r y artery, with a right modified Blalock-Taussig shunt as its blood supply. Through a right thoracotomy in the fourth intercostal space the M A P C A s were isolated. A 5-ram polytetrafluoroethylene tube was interposed between the right subclavian artery a n d a 19-mm aortic homograft tube. The homograft was oversewn proximally (Fig 2). We p l a n n e d to create a c o m m o n anastomosis between the transected M A P C A s and the distal end of the homograft. W h e n we c l a m p e d the inferior M A P C A however, the patient's h e m o g l o b i n saturation decreased to 40% and bradycardia developed, requiring removal of the clamp. Therefore, we incised the distal end of the homograft longitudinally, close to the first anastomosis, and tailored the homograft in a trouser s h a p e (Fig 3). After this modification we a p p l i e d a Castafieda clamp to the homograft and

Ann Thorac Surg 1996;61:715-7

Fig 3. The homogrgft tube was incised and tailored to a trouser shape. The upper major aortapulmonary collateral artery was anastomosed to one limb, leaving the lower major aortopuhnonary collateral artery open.

c o m p l e t e d the first anastomosis (Fig 4). Leaving the u p p e r M A P C A open, we p e r f o r m e d the second anastomosis. With this technique the patient's oxygen saturation r e m a i n e d in the high 60s. The p r o c e d u r e was safely c o m p l e t e d and the patient was extubated after 24 hours. Postoperative investigations revealed good shunt flow and perfusion to the right lung. A postoperative p u l m o nary arteriogram is shown in Figure 5. Repair with

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Fig 2. A polytetrafluoroethylene tube was interposed between the right subclavian artery and an aortic homograft tube.

Fig 4. The lower major aortopulmonary collateral artery was anastomosed to the lower limb, with the upper major aortopuhnonary collateral artery perfused by the shunt.

Ann Thorac Surg 1996;61:717-9

CASE REPORT WESTONET AL PFO AFTERHEART TRANSPLANTATION

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ventricular septal defect and major systemic to pulmonary collaterals. Ann Thorac Surg 1991;51:65-72.

Closure of a Patent Foramen Ovale and Tricuspid Valve Replacement After Heart Transplantation Mark W. Weston, MD, R a g h a v e n d r a Vijayanagar, MD, a n d N a r e n d r a S. Sastry, MD Heart Transplant Program, Tampa General Hospital, Tampa, Florida

Fig 5. Postoperative subclavian arteriogram showed unifocalized right lung with neopulmonary artery petfused by modified BlalockTaussig shunt.

ventricular septal defect closure and right ventricular to p u l m o n a r y artery conduit insertion will be p e r f o r m e d in the near future. Comment Unifocalization p r o c e d u r e s are r e q u i r e d for staging tow a r d a complete repair in some patients with p u l m o n a r y atresia a n d ventricular septal defect. If at least two-thirds of the lung segments are connected to a u n i q u e source of blood supply, a biventricular repair can usually be achieved [1-4]. The use of pericardial rolls for unifocalization in patients with very hypoplastic or absent central p u l m o n a r y arteries (as p r o p o s e d by Sawatari a n d colleagues [3]), has given good results, although our own preference is homograft tubes, which function well in this application. However, some patients will not tolerate the M A P C A occlusion r e q u i r e d during the procedure. To avoid the use of c a r d i o p u l m o n a r y bypass (which is undesirable in such patients), and w h e n anatomically possible, the technique of tailoring a t r o u s e r - s h a p e d homograft tube allows one to p e r f o r m the p r o c e d u r e u n d e r safer conditions.

References 1. Macartney FJ, Haworth SG. The pulmonary blood supply in pulmonary atresia with ventricular septal defect. In: Godman MJ, Marquis RM, eds. Pediatric cardiology, Vol 2. Edinburgh: Churchill Livingstone, 1979;314-38. 2. Sullivan ID, Wren C, Stark J, deLeval MR, Macartney FJ, Deanfield JE. Surgical unifocalization in pulmonary atresia and ventricular septal defect. A realistic goal? Circulation 1988;78(Suppl 3):5-13. 3. Sawatari K, Imai Y, Kurosawa H, Imosatsu Y, Momma K. Staged operation for pulmonary atresia and ventricular septal defect with major aortopulmonary collateral arteries. J Thorac Cardiovasc Surg 1989;98:738-50. 4. Iyer K, Mee RBB. Staged repair of pulmonary atresia with © 1996 by The Society of Thoracic Surgeons Published by Elsevier Science lnc

Patent foramen ovale has been noted after cardiac transplantation. Rarely is surgical intervention warranted. In this communication w e report a case of severe tricuspid regurgitation and paradoxical e m b o l i s m secondary to a patent foramen ovale in a patient 19 months after heart transplantation. The patient underwent successful closure of the patent foramen ovale and tricuspid valve replacement.

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atent foramen ovale has been noted after cardiac transplantation [1, 2]. Such a defect has usually not b e e n of h e m o d y n a m i c consequence. W e report the case of a patent foramen ovale in a patient after heart transp l a n t a t i o n with s u b s e q u e n t p a r a d o x i c a l e m b o l i s m . Right-to-left shunting across the defect occurred because of elevated right atrial pressure secondary to severe tricuspid regurgitation. A 54-year-old m a n with ischemic dilated c a r d i o m y o p a thy after coronary artery b y p a s s grafting u n d e r w e n t orthotopic cardiac transplantation on May 10, 1992. The donor was a 20-year-old accident victim. Gross examination of the donor heart at the time of operation including the atrial s e p t u m was normal. However, the foramen ovale of the donor heart was not e x a m i n e d with a probe. Biatrial anastomotic implantation was performed. The recipient's postoperative course was complicated by grade IIIA rejection, which eventually r e s p o n d e d to a pulse of intravenous steroids. He was discharged on s t a n d a r d triple i m m u n o s u p p r e s s i v e therapy. A n echoc a r d i o g r a m o b t a i n e d 3 w e e k s after t r a n s p l a n t a t i o n showed m o d e r a t e to severe tricuspid regurgitation secondary to a r u p t u r e d chordae and flail leaflet. At this time the mean right atrial pressure was 5 m m Hg. The patient had another episode of grade IliA rejection 4 months after transplantation. This r e s p o n d e d to two pulse doses of oral prednisone. The patient did not have any further p r o b l e m s with rejection. However, he did complain of progressive d y s p n e a on exertion a n d fatigue, which was thought to be secondary to his tricuspid regurgitation. Accepted for publication Aug 8, 1995. Address reprint requests to Dr Weston, 4 Columbia Dr, Suite 720, Tampa, FL 33606. 0003-4975/96/$15.00 SSDI 0003-4975(95)00783-0