Mitral Valve Replacement in Infants and Children

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Mitral

Valve

Replacement

in Infants

and

Children

Frank M. Galioto, Jr, MD, Frank M. Midgley, MD,

Stephen R. Shapiro, MD, Lowell W. Perry, MD,

James M. Ciaravella, Jr, MD, and Lewis P. Scott III, MD

From the Departments of Cardiology and Cardiovascular Surgery, Children ‘s Hospital National Medical Center, and Departments of Child Health and Development and Surgery, George Washington University School of Medicine, Washington, DC

ABSTRACT. Thirteen patients, ranging in age from 10

months to 19 years (mean 7.8 years) and in weight from 6.6 to 60 kg (average 29.5 kg) underwent 14 operations for mitral valve replacement with a heterograft prosthesis between January 1, 1976 and July 1, 1979 for a variety of

congenital or acquired lesions. Preoperative indications included severe refractory congestive heart failure in each patient with growth retardation, which was especially prominent in the younger patients. Operative mortality

was 14% (2/14) with both deaths occurring within 48

hours of operation in patients less than 6 years of age. All surgical survivors had clinical improvement as manifested by relief of symptoms, decrease in heart size, and signifi-cant growth. Routine postoperative catheterization in five patients revealed good initial postoperative results in those studied, with one patient having a second study 20 months after operation. He was found to have had degen-eration of his bovine prosthesis and had subsequent suc-cessful reoperation with a porcine prosthesis. Further long-term serial catheterizations are needed to further document the history of heterograft prosthesis in chil-dren, but they are preferred to mechanical valves became of the lack of need for long-term anticoagulants and the absence of thromboembolism complications. This series

suggests that mitral valve replacement, when indicated by refractory congestive heart failure and growth retar-dation, can be successfully performed even in infants and small children. Surgery should not be postponed to allow for subsequent patient growth if the natural history of the disease is of progression. Pediatrics 67:230-235, 1981; valve replacement, congenital heart disease, surgery.

Mitral valve replacement for incompetence or

stenosis has become an accepted therapeutic

mo-dality in the adult.’3 Experience with mitral valve

Received for publication March 31, 1980; accepted May 23, 1980.

Reprint requests to (F.M.G.) Department of Cardiology, Chil-dren’s Hospital National Medical Center, 1 1 1 Michigan Aye, NW, Washington, DC 20010.

American Academy of Pediatrics.

replacement in the pediatric age group has been

limited, especially in infants and children where the

small size of the mitral orifice may make surgery

technically more difficult.49 This study, at the

Chil-dren’s Hospital National Medical Center, presents

the recent experience with mitral valve replacement in infants and children for a variety of congenital

and acquired conditions for which medical

manage-ment was ineffective.

MATERIALS AND METHODS

Thirteen patients from 10 months to 19 years of

age (mean 7.8 years) underwent 14 operations for

mitral valve replacement at the Children’s Hospital

National Medical Center between January 1, 1976

and July 1, 1979 (Table). Two patients were less

than 2 years of age and an additional five were

between 2 and 6 years of age at the time of initial

operation. Of the remaining six patients, three were

between 10 and 15 years of age and three were older

than 15 years. Weights ranged from 6.6 to 60.0 kg

with an average of 29.5 kg.

Four patients had residual mitral regurgitation

following repair of partial or complete

atrioventric-ular canal. Three patients had an Ebstein-like

mal-formation of the systemic atnoventricular (AV)

valve associated with L-transposition of the great

arteries. One of these three had situs inversus and

a ventricular septal defect (I,D,D) while the other

two had normal situs (S,L,L). These three patients

all had severe valvar regurgitation and rapidly

pro-gressive cardiomegaly. Three patients from the

ear-her part of the series had severe mitral regurgitation

following rheumatic fever with one having had

pre-vious replacement of her mitral valve with a

ball-valve prosthesis. She had had a previous

cerebro-vascular accident with no sequelae. One of the

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regur-gitation which was judged not to be severe enough

to warrant aortic valve replacement. One patient,

who had had previous repair of a ventricular septal

defect had pulmonary vascular obstructive disease

and had developed massive mitral regurgitation

following endocarditis. One patient had parachute

mitral valve complex associated with severe mitral

stenosis and a final patient had lupus vasculitis with

mitral valve degeneration and regurgitation.

All patients had congestive heart failure which

was refractory to medical therapy with digoxin and

diuretics. Clinical deterioration had been noted in

all, especially in the younger infants and in those

with the Ebstein-like malformation and

L-transpo-sition of the great arteries. Preoperative

electrocar-diograms revealed significant hypertrophy of the

systemic ventricle in each with additional pulmonic

ventricular hypertrophy in four. The patient with

a previous ball-valve replacement had chronic atnal

fibrillation. All patients in the group had significant

cardiac enlargement on chest x-ray with a

cardi-othoracic ratio greater than 62% in each (Fig 1).

Preoperative cardiac catheterization revealed

ele-vated left atriaJ or pulmonary capillary wedge

pres-sures in all patients. Nine patients (69%) had mean

pressures greater than 15 mm Hg in either the left

atrial or pulmonary arterial wedge positions with

an average for the entire group of 19.3 mm Hg. The

left ventricular end-diastolic pressure was greater

than 15 mm Hg in seven patients (54%).

At surgery, each valve was inspected by direct

vision and was judged not to be repairable.

Inade-quate tissue was present in all cases with AV canal

anatomy and with the Ebstein-like deformity of the

systemic AV valve. Ruptured chordae and valvular

degeneration were present in the patients with a

history of rheumatic fever and in the child with

lupus vasculitis. The infant with parachute mitral

valve had fused commissurae and chordal

appara-tus which could not be opened due to the single

obstructing papillary muscle. Initial replacement

was with a porcine plosthesis (Hancock

Laborato-ries, Inc, Anaheim, CA) in 12 patients and a bovine

prosthesis (Shiley, mc, Irvine, CA) in one. The

patient who had two operations received the bovine

prosthesis initially. It was replaced with a porcine

prosthesis 21 months after implantation because of

valvar degeneration.

RESULTS

Operative mortality was 14% (2/14) with both

deaths occurring in the 2- to 6-year age group. One

death occurred in a patient who had severe mitral

regurgitation following initial repair of a complete

AV canal two months previously. The other death

was in the child with Ebstein’s malformation of the

Fig 1. Preoperative (top) and 5 months postoperative (bottom) chest x-rays from G.D., a 3-year-old boy with L-transposition of the great arteries and systemic atnoven-tncular valve regurgitation due to an Ebstein-like malfor-mation of the valve. Radiographs illustrate marked im-provement in cardiac dilation following replacement of the valve with a No. 25 porcine prosthesis. Permanent pacing lead was implanted at surgery but has not been used for pacing.

systemic atrioventricular valve associated with

yen-tricular septal defect, situs inversus, and

L-trans-position of the great arteries. This patient was the

only one in the entire series with a significant

left-to-right shunt. Both deaths occurred within 48

hours of operation. One patient sustained a

mid-brain infarction during operation and has a

perma-nent paraplegia. One late noncardiac death in the

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All

patients who survived surgery had marked

clinical improvement initially with reliefofthe signs

and symptoms of congestive heart failure. Heart

size decreased an average of 17% for the group.

However, two patients had no decrease in heart

size. One has significant aortic regurgitation and

the other pulmonary vascular obstructive disease,

both of which were present preoperatively.

Electro-cardiograms after operation revealed no new

rhythm disturbances and a reduction in systemic

ventricular forces and in left atrial enlargement in

all except one patient who had left bundle branch

block. The patient with chronic atrial fibrillation

remained in that rhythm. Permanent pacing leads

were implanted in all patients with L-transposition

of the great arteries because of the common

asso-ciation with complete heart block in those patients.

Pacemakers

were

not required, however, in any of

the three patients with that lesion.

Two-dimen-sional echocardiography in nine of the survivors,

eight to 45 months postoperatively, revealed no

thickening of the heterograft valve except in the

patient with the bovine prosthesis. Anticoagulation

was not used in

any of the patients

less than 6 years

of age. During the initial six weeks after operation,

those patients more than 6 years of age were

anti-coagulated but no long-term anticoagulant therapy

was used even in this group.

Routine cardiac catheterization was performed

six to 14 months (average 11 months) after

opera-tion in five ofthe surviving patients with one patient

having two studies (Fig 2). There was a 0- to 2-mm

Hg gradient across the prosthetic valve in four

patients on initial study. One child, who had

endo-carditis and pulmonary vascular obstructive

dis-ease, had a 5-mm Hg gradient with continued

ele-vation of her pulmonary vascular resistance.

The patient who received a bovine prosthesis had

no gradient at his initial postoperative

catheteriza-tion, 10 months after surgery. However, because of

recurrent cardiomegaly and signs of mitral stenosis,

repeat catheterization was performed 20 months

after operation. That catheterization revealed

se-vere stenosis with a 15-mm Hg transvalvar gradient.

Successful reoperation using a porcine prosthesis

was performed 21 months after the initial operation.

DISCUSSION

This experience indicates that infants and small

children can undergo successful mitral valve

re-placement if clinically indicated. All patients were

unresponsive to medical therapy and had valves

that were not amenable to a plastic repair. Valve

replacement was considered to be the only possible

therapy at time of operation. Significant growth

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Fig 2. Preoperative (top) and postoperative (bottom) systemic ventriculograms from G.D., the patient whose chest x-rays are shown in Fig 1. Top, systemic ventricle (V) leads to L-transposed aorta (Ao) with significant opacification of left atrium (LA) due to atrioventncular valvar regurgitation. Bottom, porcine prosthesis is iden-tified by its radioopaque ring (arrow). Note complete relief of regurgitation.

age and was especially prominent in the two

chil-dren who died at operation. Recognition of

progres-sive growth failure and refractory congestive heart

failure in this class of patients should lead to early

surgical intervention before the child becomes

de-biitated and a greater surgical risk.

The surgical mortality of 14% occurred in the

patients with the most severe mitral regurgitation

and congestive heart failure. Other surgical series

in children have had higher mortality rates,6’9’

possibly due to delay in medical therapy before

surgical intervention. Late deaths, as reported by

others’#{176}12’3 in similar postoperative periods, have

not appeared in this series. Those late deaths were

often related to thromboembolism secondary to the

use of mechanical valves.

At operation, prostheses of as large a diameter as

possible were placed in the mitral position to allow

for an adequate valve orifice with growth. No

spe-cial techniques were needed to enhance the size of

the mitral annulus. The preoperative mitral

regur-gitation may have led to a dilation of the annulus,

thereby allowing for the use of large diameter

valves. There have been no postoperative

throm-boembolic complications in the group despite the

absence of long-term anticoagulants. This is

con-sistent with the findings of Hetzer’4 who reported

no thromboembolism in their patients who were

hemodynamically stable.

The selection of the porcine or bovine prosthesis

was made because of the lack of need for long-term

postoperative anticoagulants which are a problem

in active children who are predisposed to trauma.

The natural history of these prostheses is unknown,

although there are disturbing reports appearing in

the literature indicating that, in selected cases,

there has been accelerated degeneration of the

valve tissue especially in children.’’7 We have not

seen evidence of valvular degeneration in the

por-cine group, even after the key period of more than

30 months of implanation which was reported by

Sanders.’8 However, when compared with the early

problems with mechanical prosthetic valves,6’7’9 the

porcine prosthesis is preferred at present. Our

ex-perience with degeneration of the bovine

hetero-graft is unusual but it has been seen in another

child.’9 The selection of valve types in the future

will

continue to change as more information is

gleaned from the currently available heterografts

and the other prosthetic valves in use. Routine

postoperative cardiac catheterization is needed in

this class of patients to further document the

nat-ural history of heterograft valves.

Postoperatively, all survivors initially had

marked improvement in congestive heart failure.

There has been adequate growth and development

after valve replacement in all patients as has been

noted by others.#{176} Except for the 17-year-old who

sustained a midbrain infarction, the patients who

survived did not have a protracted hospitalization.

There were no cases of postoperative infection and

the only rhythm disturbance was in the patient who

had preoperative atrial fibrillation.

The postoperative catheterization studies

mdi-cate adequate relief of valvular obstruction or

in-sufficiency in each of the cases studied except for

the child with the degeneration of the bovine

het-erograft. The persistent cardiomegaly in two

pa-tients is due to their associated cardiac or

pulmo-nary lesions and not to mitral regurgitation or

ste-nosis which is clinically absent. Obviously, the

post-operative follow-up has been too short to make

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chil-dren, but it is clear that they are in much better

cardiovascular health after surgery than they were

before and have been able to resume a more normal

childhood.

Our experience suggests that mitral valve

replace-ment, when clinically indicated by signs of growth

failure and progressive congestive heart failure, can

be carried out safely in infants and children.

Sur-gical intervention should not be delayed beyond the

point when the patient is judged to be in refractory

congestive heart failure and has had signs of growth

failure if the natural history of the disease itself is

of progression.

REFERENCES

1. Starr A, Edwards ML: Mitral replacement: Clinical

experi-ence with a ball-valve prostheses. Ann Surg 154:726, 1961 2. Rahimtoola SH (ed): Symposium on current status of valve

replacement, parts I and II. Am J Cardiol 35:710, 843, 1975

3. Bonchek LI, Dobbs JL, Maths AF, et al: Roentgenographic

identification of Starr-Edwards prostheses. Circulation 47: 154, 1973

4. Freed MD, Bernhard WF: Prosthetic valve replacement in children. Prog Cardiovasc Dis 17:475, 1975

5. Carpentier A, Branchini B, Cour JC, et al: Congenital mal-formations of the mitral valve in children. J Thorac

Car-diovasc Surg 72:854, 1976

6. Blieden LC, Castaneda AR, Nicoloff DM, et al: Prosthetic valve replacement in children. Ann Thorac Surg 14:545,

1972

7. Nonoyama A, Masuda A, Kasahara K, et al: The use of the

Bjork-Shiley prosthetic valve in children under 10 years of

age. Jpn Circ J 41:401, 1977

8. Braunwald NS, Brais M, Castaneda A: Considerations in the

development of artificial heart valve substitutes for use in infants and small children. J Thorac Cardiovasc Surg 72:

539, 1976

9. Berry BE, Ritter DG, Wallace RB, et al: Cardiac valve replacement in children. J Thorac Cardiovasc Surg 68:705,

1974

10. Chen 5, Laks H, Fajan L, et al: Valve replacement in children. Circulation 56 (suppl 2):117, 1977

11. Mathews RA, Park SC, Neches WH, et al: Valve replacement in children and adolescents. J Thorac Cardiovasc Surg 73: 872, 1977

12. Bloodwell RD, Haliman GL, Cooley DA: Cardiac valve

replacement in children. Surgery 63:77, 1968

13. Klint R, Hernandez MD, Weldon C, et al: Replacement of

cardiac valves in children. J Pediatr 80:980, 1972

14. Hetzer R, Hill JD, Kerth WJ, et al: Thromboembolic

corn-plications after mitral valve replacement with Hancock xen-ograft. J Thorac Cardiovasc Surg 75:651, 1978

15. Geha AS, Laks H, Stansel HC, et al: Late failure of porcine

valve heterografts in children. J Thorac Cardiovasc Surg 78:351, 1979

16. Ferrans VJ, Spray TL, Billingham ME, et al: Structural changes in glutaraldehyde-treated porcine heterografts used

as substitute cardiac valves. Am J Cardiol 41:115, 1978

17. Kutache LM, Oyer P, Shummway N, et al: An important

complication of Hancock mitral valve replacement in chil-then. Circulation 60 (suppl 1):98, 1979

18. Sanders SP, Freed MD, Norwood WI, et al: Early failure of porcine valves implanted in children, abstracted. Am J Car-diol 45:449, 1980

19. Trusler GA: Discussion of a paper. J Thorac Cardiovasc Surg 78:362, 1979

20. Friedman 5, Edmunds LH, Cuaso CS: Long-term mitral

valve replacement in young children. Circulation 57:981,

1978

PAEDIATRICS CLASSIFIED

The International Classification of Diseases (lCD) is limited to 999 main

three-figure diagnostic categories, each of which may be subdivided into ten

more using a fourth digit. With a view to overcoming [the limitation]. ..the

British Paediatnc Association, with the cooperation of the Office of Population,

Censuses and Surveys, has now produced its own supplementary classification

for use in paediatrics. This new classification is entirely compatible with the

lCD and it uses the identical numerical diagnostic categories to the fourth digit.

As in the lCD, vol. 1 contains a numerical list of diagnostic categories, while vol.

2 provides an alphabetical index. The two main differences are that terms

irrelevant to paediatrics have been omitted, while greater diagnostic specificity

is provided where necessary by a fifth digit. The resulting publication is smaller,

cheaper, and more conveniently handled than the original lCD and will be

warmly welcomed in paediatric departments wherever English is spoken...

The B.P.A. has also produced a perinatal supplement in which both the

extended numerical coding and the alphabetical index of terms relevant to

maternity and neonatal practice have been abstracted into a single volume. ...

Submitted by Student

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1981;67;230

Pediatrics

Ciaravella, Jr and Lewis P. Scott III

Frank M. Galioto, Jr, Frank M. Midgley, Stephen R. Shapiro, Lowell W. Perry, James M.

Mitral Valve Replacement in Infants and Children

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