POSTGRAD. MED. J. (I96I), 37, 653

THE OPERATIVE CLOSURE OF VENTRICULARSEPTAL DEFECTS IN CHILDHOOD

W. T. MUSTARD, M.D.Assistant Professor, University of Toronto. Associate Surgeon, Hospitalfor Sick Children, Toronto

THE successful operative closure of a ventricularseptal defect accomplished by Lillehei, Cohen,Warden, Ziegler and Varco (I955) not onlyawakened the latent interest of internists andpathologists but introduced a new surgical field.First described by Roger in I879, the defect waswell documented by Abbott in 1932 who corre-lated the pathology with clinical findings.

Incidence and Natural HistoryVentricular septal defect is the commonest con-

genital heart lesion in childhood and probablyaccounts for 20% of all heart defects (Keith, Rowe,and Vlad, I958).

It has been reported to be the second mostcommon cause of death in children sufferingfrom heart disease (Zacharioudakis, Terplan andLambert, 1957). An accurate appraisal of thelife-span of a child born with a ventricular septaldefect is difficult to secure. Death in the firstyear of life from an isolated ventricular septaldefect is not uncommon. If an infant survivesthe first year of life without developing heartfailure, or with proper medical management ofheart failure, life expectancy should depend uponthe size of the defect, the volume of flow throughit and the pulmonary resistance. As pulmonaryvascular resistance increases, the volume of shuntdiminishes and the child may lead a relativelyasymptomatic life until such a time as the shuntbecomes bi-directional or from right to left andthe patient succumbs in early adult life. In aseries of 98 catheter-proven ventricular septaldefects in children, Fyler, Rudolph, Wittenborgand Nadas (I958) found only one death afterinfancy. There were five deaths in infancy inthis study.

Pathological AnatomyThe defect in the ventricular septum is usually

in the region of the membranous portion, moreaccurately defined as the area between thepapillary muscle of the conus and the cristasupraventricularis of the right ventricle. Thedefects are not restricted to this membranous

FIG. i.-The classical ventricular septal defect in themembranous portion of the septum. We have founda key suture placed through the annulus of theseptal leaflet of the tricuspid valve from the rightatrium to be very useful. If this suture is accuratelyplaced, tension on it will demonstrate the inferiormargin of the defect and the course of the bundleof His defined.

portion of the septum. In those instances wherethe defect is above the crista supraventricularis orin the muscular portion of the septum, the rimusually consists of smooth muscle tissue and iscircular in outline. When the defect is in themembranous portion of the septum, the shape isusually oval and the superior margin may extendto the aortic valve ring. The inferior margin ismost variable, partly muscular and partly fibrous,and is limited by the papillary muscle of theconus (Fig. i). When the defect is small, i cm.or less, there may be a well-defined fibrousmargin between the septal leaf of the tricuspidvalve and the aortic leaf of the mitral valve.However, when the defect is large, the septal

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FIG. 2.-The plain radiograph of an infant of fourmonths with catheter-proven isolated ventricularseptal defect. The heart is enlarged and the lungfields show increased vascular marking.

leaf of the tricuspid valve occludes the lowerthird of the defect and the margin then becomesthe junction of the aortic leaf of the mitral valveand the septal leaf of the tricuspid valve.There is occasionally a white fibrous area on thewall of the right ventricular myocardium oppositethe jet stream of the ventricular septal defect.Spontaneous closure has been reported even indefects which were considered large in infancy(Evans, Rowe and Keith, I960).

DiagnosisA harsh pan-systolic murmur in the third or

fourth left interspace with a palpable thrill in anacyanotic child is almost pathognomonic of ven-tricular septal defect. In infants with pulmonaryhypertension, dyspnea may be present at rest butin older children exercise tolerance is remarkableand many lead a normal, active life. In theinfant a classical murmur is present with ahistory of failure to thrive and repeated respira-tory infections. Cardiac enlargement is presentwith increased hilar vascular markings (Fig. 2)and the electrocardiogram may demonstrate rightor combined ventricular hypertrophy. In theolder child exercise tolerance may be normal oronly slightly limited. However, in appearance,our group of operated patients were usually thin,poorly developed children with a bulging pre-cordium. If the defect is moderate or large, athrust is present over the apex of the heartaccompanied by a coarse thrill. On radiologicalexamination the heart may be normal in size butis usually enlarged, particularly the left atrium,with bulging pulmonary artery, increased hilarshadows and hilar pulsations. We consider aplain radiograph to be of considerable surgicalsignificance, and increased vascular markings well

FIG. 3.-The radiograph of a child age io years with acatheter-proven ventricular septal defect. Theheart is enlarged and the lungs plethoric. Despitesystemic pressure in the right ventricle, the defectwas closed successfully.

out into the periphery even in the presence of pul-monary hypertension, indicates increased flowrather than increased resistance (Fig. 3). In theolder child the electrocardiogram may be normalor show left'ventricular hypertrophy, combinedhypertrophy or a moderate degree of right hyper-trophy. The axis is usually in the normal range.Right axis deviation is present in cases withsevere pulmonary hypertension. Cardiac catheter-ization, although not as useful in the infant as inthe older child, usually confirms the diagnosis andmay demonstrate an additional lesion such as apatent ductus arteriosus. Selective angiocardio-graphy may reveal recirculation of the contrastmedium through the defect. Occasionally thedefect may be outlined and an indication of itssize obtained.

Estimation of Pulmonary Blood FlowOn physical examination children with a large

pulmonary blood flow will demonstrate an over-active heart with a good systolic murmur andthrill and occasionally an inflow diastolic murmurat the apex. Children with a low flow and in-creased pulmonary vascular resistance usuallyhave a soft murmur and no thrill. On X-rayexamination DuShane, Brandenburg, Wood andKirklin (1956) have pointed out that in patientswith a large flow the left ventricle is enlarged, theright ventricle dilated, and enlarged pulmonary

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November I96I MUSTARD: Operative Closure of Ventricular Septal Defects in Childhood

FIG. 4.-The radiograph of a 14-year-old girl with acatheter-proven isolated ventricular septal defect.The heart is small and the lung fields are clear.Systemic pressure was present in the pulmonaryartery and the child was considered unsuitable forsurgery.

artery shadowing -seen well out into the lungfields (Fig. 3). In children with a small flow, theleft ventricle is not enlarged, the right ventriclenot dilated and the lung fields are clear (Fig. 4).

Associated DefectsA combination of ventricular septal defect and

patent ductus arteriosus may be a cause of failurein infancy. The volume of flow through theductus may be as great as that through the ven-tricular septal defect. Cardiac catheterization isvery useful, particularly if the catheter is passedthrough the ductus and into the aorta. Ven-tricular septal defect associated with aortic in-sufficiency although rare, is sometimes difficult todistinguish from a ventricular septal defectassociated with patent ductus arteriosus. Leftheart catheterization may be necessary to provethe diagnosis and occasionally the diagnosis canonly be made at operation. Isolated atrial secun-dum defect with a ventricular septal defect can beproved by cardiac catheterization. Ventricularseptal defect combined with coarctation of theaorta is not uncommon; absent femoral pulses ora difference in the blood pressure in the arm andleg is helpful to aid in diagnosis.

Children with tetralogy of Fallot with normaloximetry may be difficult to distinguish on clinicalexamination. Cardiac catheterization with a marked

pressure differential on passing through the pul-monary valve makes the diagnosis more certain.

Indications for OperationUnder One Year of Age. At the time of

writing most surgeons familiar with the use ofextra-corporeal circulation feel that infants toleratethe heart-lung machine poorly. For this reason,these cases should be treated medically until theinitial flooding of the lung has passed. Duringthis period banding of the pulmonary artery ashas been suggested by Muller and Dammann(1952) and reported by Sirak, Hosier and Clat-worthy (I959) may be a temporary measure totide these infants over until the optimum age forextra-corporeal circulation is reached. However,in the near future an operative heart-lung machineto fill the requirements of an infant may bedeveloped, allowing these infants to be operatedupon at a young age, as has recently been demon-strated by Kirklin, McGoon and DuShane (I96o).

Over One Year of Age. In the selection ofpatients for operation over the age of one year,one must be guided by the clinical course and bycertain definitive signs. If a child is asympto-matic and has the classical murmur of a ven-tricular septal defect, operation may be deferredfor some years. If, however, the child has anenlarging heart, operation becomes imperative.We have been guided by the use of the X-ray,the electrocardiogram, and cardiac catheterization.If a large difference in oxygen saturation betweenthe right atrium and right ventricle is presentwith increased lung vascularity, the child shouldbe operated upon at any time over one year of age.If the pulmonary artery pressure is more than 700/of the systemic pressure, operation becomes im-perative. If, however, the child is clinically well,the increase in oxygen saturation between theright atrium and the right ventricle is not large,and the lungs do not show gross plethora, opera-tion may be deferred for some years. In our clinicwe have come to recognize that the child with aventricular septal defect proven by catheterization,demonstrating enlargement of the heart and deep-ening of the Q waves in lead V6 of the electro-cardiogram, should be operated upon before theage of six. The development of pulmonary hyper-tension is always a threat to these children and,although we operate upon children with identicalpressures in right and left ventricles, this alwayspresents some hazard in the post-operative period.Over the course of time the age for elective opera-tion will become more definitive, as it has in otherdefects, and the inoperability of a patient willbecome more defined. At the present time we feelthat children with a shunt from right to left shouldbe considered inoperable. The mortality rate of un-

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complicated ventricular septal defects in childhoodshould be quite low in the hands of experiencedsurgeons, somewhere in the neighbourhood of z to5 / (Kay, I960; Kirklin, McGoon and DuShane,I960). A natural rise in operative mortality canbe expected in defects complicated by otherlesions and by pulmonary hypertension.

Technique of OperationThe use of the artificial heart-lung apparatus is

mandatory at the present time for the closure ofventricular septal defects because of the length oftime the heart is out of circulation. As con-fidence in the pump has increased and surgeons'experience has been gained, longer time is takento close ventricular septal defects than in theoriginal group of cases. Although we have doneseveral through the right atrium, the child's rightatrium is rather small and our preference is toclose these defects through a right ventriculotomyin the child whose myocardium is not impaired.The incision should be kept high in the rightventricle in order to cause less of a scar in the bodyof that ventricle and any coronary vessels shouldbe avoided. Occasionally an aberrant left coronarymay make right atriotomy obligatory but we havenot encountered this situation.

If a patent ductus is present, it must be ligatedbefore going on the pump and this may be doneeither through the split sternal approach or if thediagnosis is definite, through a left thoracotomy,crossing over to the right side but not entering thepleural cavity. A left superior vena cava should betourniqueted before going on the pump. Thedefect is identified and the competence of theaortic valves inspected; even if there is a slightleak through the aortic valves due to manipulation,we feel it is wise to identify the position of thevalves accurately before occluding the aorta evenfor short periods because of the danger of placinga stitch through the aortic valve. As experiencehas been gained, the method of closure in eachsurgeon's hands becomes more definitive. Ourpreference is for the use of double-ended oo silksutures reinforced with an Ivalon pledget wherenecessary, if the rim is muscular, and alwaysavoiding the left side at the inferior margin of therim to lessen the likelihood of heart block. Wefind that we are using a Teflon patch in more casesthan doing direct suture and this may be becausethe defects that we are operating upon are reason-ably large. In the membranous septal defect we feelthat the key suture in the right inferior portionshould be placed from the atrial side, in the annulusof the tricuspid valve (Fig. i). When the defectis closed it is wise to have the heart beating toallow left-sided decompression. It has not beenour custom to decompress the left side of the

heart since the heart is beating well when com-plete closure is effected. In our earlier casesacetylcholine or potassium arrest was used, but wehave abandoned this in favour of short periods ofaortic occlusion with anoxic arrest.

Ventricular-Atrial Septal DefectWe have encountered two cases in which the

defect in the membranous portion of the septumentered the right atrium through the base of thetricuspid valve. These cases pose a problem indiagnosis and may be thought to be a ventricularseptal defect and atrial septal defect because of therise in oxygen saturation. However, the diagnosisshould be suspected on the basis of an apparentatrial septal defect with the clinical findings of aventricular septal defect. In one of our cases a jetwas present in the atrium and the defect wasrepaired very easily through a right atriotomy;in the second case the jet was not really lookedfor and a right ventriculotomy revealed a ven-tricular-atrial septal defect which was closedthrough the right ventricle.

Ventricular Septal Defect Associated withOther Defects

Patent Ductus Arteriosus. It is obvious that thepatent ductus arteriosus must be dealt with beforeany extra-corporeal circulation is feasible, other-wise, when the heart is open, one is faced with atremendous flow into the field. The surgicalmanagement has been mentioned above. In ourclinic I3 infants under one year of age with com-bined ventricular septal defect and patent ductusarteriosus have had the ductus only closed withnine survivors.

Multiple Ventricular Septal Defects. One shouldsuspect another muscular defect or multipledefects when the ventricular septal defect has beenclosed and red blood continues to well into theright ventricle through the septum (and not fromthe pulmonary artery).

Aortic Insufficiency. If this diagnosis is not madepre-operatively it becomes obvious after rightventriculotomy. Blood from the pump oxygenatorpasses through the defect because of the in-competent aortic valve. If the aortic valve isslightly incompetent, closure of the defect alonemay reduce the incompetence to an acceptablelevel. However, if the aortic valve is grossly in-competent, it will not do so, and this proved to bethe case in one of our children who died post-operatively because of aortic incompetence follow-ing successful closure of a ventricular septal defect.If the diagnosis is suspected or made beforeoperation, it is wise to enter the aorta first, repairthe aortic incompetence by bicuspidization of theredundant cusp, and then, when the right ven-

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tricle is opened without aortic occlusion, theaortic valves can be inspected for competency.We have had four such cases. One of them diedas a result of failure to repair the aortic incom-petency. The other three had the aortic valverepaired and one died. Two are now well and haveslight signs of aortic incompetency.

Atrial Septal Defect. The atrial septal defect isof the secundum type and closure is effected witha running suture. If the right atriotomy is leftopen and the ventricular septal defect then closed,both right ventriculotomy and atriotomy can beclosed at the same time.

Severe Pulmonary Hypertension. The rightventriculotomy, particularly if it is of any extent,may lessen the function of the right ventricle inpatients who have pulmonary hypertension. Ex-posure through the right atrium may be difficultin children whose tricuspid valves are normal andthe right atrium small. However, if tricuspid in-competence is present or if the atrium is largeenough, adequate exposure of the ventricularseptal defect can be obtained through the atrium.We have employed this approach on a number ofoccasions and have found it very satisfactory.One may retract the septal leaf of the tricuspidvalve or divide it to expose the defect. Anotheralternative is to divide the valve along the annulusand reflect the septal leaflet of the valve. Repairthrough the right atrium is more difficult thanthrough the right ventricle, but the immediatepost-operative course is less hazardous in a patientwho has already pulmonary hypertension and afailing right ventricle. However, we have alsofound a ventricular septal defect in the muscularportion of the septum which we were unable tosee and identify through a right atrial approach.Controversy still exists as to the proper approachin cases of pulmonary hypertension. An advantageof the atriotomy is inspection of the tricuspid valvefor incompetence. The question of fenestration ofa patch to allow an escape-valve mechanism inthese cases remains unanswered. The tendency ofmost surgeons in this field is toward completeclosure of the defect.

Heart BlockThe most serious complication is heart block. A

comprehensive survey of this has been recentlypublished by Lauer, Ongley, DuShane andKirklin (I960). Of 48 patients who developedheart block, i8 died in hospital. Twelve weredischarged with complete heart block and four ofthese died subsequently. The standard treatmentat the present time is the use of the pacemakerand some form of electrode in the myocardium(Weirich, Gott and Lillehei, 1958). However, thetreatment of heart block is in its prevention, and a

knowledge of the pathway of the bundle of Hiswith careful monitoring during the closure of thedefect is essential. For this reason we prefer notto use arrest except short periods of anoxic arrest toenable the pathological anatomy to be visualized.Our preference is to lower the body temperaturewith the use of a heat exchanger (Brown, Smith,Young and Sealy, 1958) and to reduce the flow rateto allow the defect to be seen more clearly.

Right Ventricular FailureProlonged cardiac arrest produces myocardial

necrosis, arrest induced by potassium citrateresulting in the greatest damage (Willman,Cooper, Zafiracopoulos and Hanlon, 1959; McFar-land, Thomas, Gilbert and Morrow, I960). Shortperiods of anoxic arrest will reduce the damage tothe myocardium reflected in the post-operativeperiod by right heart failure. A short, high rightventriculotomy will lessen the splinting effect of along incision in the wall of the right ventricle. Incases of pulmonary hypertension, operationthrough the right atrium may be of some value inpreventing right ventricular failure. Tricuspidincompetence, if recognized, should be dealt withat the same time as the ventricular septal defect isclosed. Supportive measures such as the use oftracheostomy and a ventilator may be life-saving.

RecurrenceWe feel that recurrence of the ventricular septal

defect (as in the treatment of patent ductusarteriosus by suture ligation) develops at the timeof operation from improperly placed sutures.Closure of the defect by direct sutures under toomuch tension will inevitably cause one or more topull out. The same situation applies when a pros-thesis is used and the sutures are placed improperlyor too shallow or not buttressed by some prostheticmaterial in muscular rims.

SummaryVentricular septal defect is the commonest

lesion encountered in congenital heart disease inchildren. The natural history of the defect is stillsomewhat obscure. Spontaneous closure has beenreported. There is strong evidence to support thefact that pulmonary hypertension does not developnecessarily unless it is already present in child-hood. These facts tend to confuse the indicationsfor operation. However, in children with largedefects and enlarged hearts with a high flow to the'lungs, operation does appear to be indicated. Inthe infant who fails to thrive or whose failurecannot be relieved by a proper medical regimesome form of operation should be attempted.Diminishing the flow to the lungs by banding thepulmonary artery, while appearing to be a simple

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procedure, may not be so simple to correct lateron. It is possible that with the development ofbetter heart-lung machines these defects shouldbe closed directly, even in the first year of life.The mortality rate of uncomplicated ventricular

septal defects in childhood should be about 2 to%/. In defects complicated by other lesions a

natural rise in operative mortality can be expected.

When the flow is balanced or bi-directional, as aresult of pulmonary hypertension, the mortalityrises to about 25%. The post-operative recur-rence rate and the incidence of heart block willbecome lower with increasing experience.

All in all, the picture for operative correction ofventricular septal defects in childhood is quiteencouraging.

REFERENCESABBOTT, M. E. (1 932): Congenital Heart Disease, Nelson's Loose-Leaf Medicine, 4, 207.BROWN, IVAN W., SMITH, W. W., YOUNG, W. A., and SEALY, W. C. (I958) Experimental and Clinical Studies of

Controlled Hypothermia Rapidly Produced and Corrected by a Blood Heat Exchanger During ExtracorporealCirculation, J. thorac. Surg., 36, 497.

DUSHANE, J. W., BRANDENBURG, R. O., WOOD, E. H., and KIRKLIN, J. W. (1956): Criteria for Selection of Patientswith Ventricular Septal Defects for Surgical Repair, Circulation, I4, 929.

EVANS, J. R., ROWE, R. D., and KEITH, J. D. (I960): Spontaneous Closure of Ventricular Septal Defects, Ibid., 22, 1044.FYLER, D. C., RUDOLPH, A. M., WITTENBORG, M. H., and NADAS, A. S. (I958): Ventricular Septal Defect in Infants and

Children. A Correlation of Clinical, Physiologic and Autopsy Data, Ibid., I8, 833.KAY, E. B. (I960): Discussion of paper by Kirklin, J. W., McGoon, D. C., and DaShan2, J. W., J3. thorac. Surg.,

40, 799-KEITH, J. D., ROWE, R. D., and VLAD, P. (I958): 'Heart Disease in Infancy and Childhood'. New York: Macmillan.KIRKLIN, J. W. (ig6o): Surgical Correction of Ventricular Septal Defects in Infants. Paper read at American Academy

of Pediatrics Meeting, October I960, Chicago., McGooN, D. C., and DUSHANE, J. W. (I960): Surgical Treatment of Ventricular Septal Defects, J. thorac. Surg.40, 763.

LAUER, R. M., ONGLEY, P. A., DuSHANE, J. W., and KIRKLIN, J. W. (I960): Heart Block After Repair of VentricularSeptal Defect in Children, Circulation, 22, 526.

LILLEHEI, C. W., COHEN, M., WARDEN, H. E., ZIEGLER, N. R., and VARCO, R. L. (1955): The Results of Direct VisionClosure of Ventricular Septal Defects in Eight Patients by Means of Controlled Cross Circulation, Surg. Gynec.Obstet., 101, 447.

MULLER, W. H., JR., and DAMMANN, J. F., JR. (1952): The Treatment of Certain Congenital Malformations of theHeart by the Creation of Pulmonic Stenosis to Reduce Pulmonic Hypertension and Excessive Pulmonary BloodFlow, Ibid., 95, 213.

McFARLAND, J. A., THOMAS, L. B., GILBERT, J. W., and MORROW, A. G. (I960): Mvocardial Necrosis FollowingElective Cardiac Arrest Induced with Potassium Citrate, J. thorac. Surg., 40, 200.

ROGER, H. (I879): Recherches cliniques sur la communication congenitale des deux cceurs, par inocclusion du septuminterventriculaire, Bull Acad. Mid. (Paris), 8, 1074, II89.

SIRAK, H. D., HOSIER, D. M., and CLATWORTHY, H. W. (1959): Interventricular Septal Defects in Infancy. A Two-stage Approach to its Surgical Correction, New Engl. J3. Med., 260, 147.

WEIRICH, W. L., GOTT, V. L., and LILLEiiEI, C. W. (1958): Treatment of Complete Heart Block by Combined Use ofMyocardial Electrode and Artificial Pacemaker, Surg. Forum, 8, 360.

WILLMAN, V. L., COOPER, T., ZAFIRACOPOULOS, P., and HANLON, C. R. (I959): Depression of Ventricular FunctionFollowing Elective Cardiac Arrest with Potassium Citrate, Surgery, 46, 792.

ZACHARIOUDAKIS, S. C., TERPLAN, K., and LAMBERT, E. C. (1957): Ventricular Septal Defects in the Infant Age Group,Circulation, i6, 374.

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