Thorax (1972), 27, 754.

Complications following closure of atrial septaldefects of the inferior vena caval type

J. K. ROSS1 and D. C. JOHNSON

National Heart Hospital, London W.]

An atrial septal defect of the inferior vena caval type presents complicated anatomy to thesurgeon at operation. Four cases are presented illustrating two complications of repair.Incomplete closure or reopening due to disruption of the suture line may be prevented byaccurate identification of the anatomy and a patch closure. Two cases of inadvertent diversionof the inferior vena cava into the left atrium are presented and the methods of diagnosis andtechniques of repair are discussed. Mitral regurgitation due to ballooning of the posterior cusp

in systole was an associated lesion in two cases of atrial septal defect of this type.

The secundum type atrial septal defect most com-monly needs closure in young asymptomaticpatients, so that any surgical complication is par-ticularly disconcerting. The inferior vena cavaltype of defect presents more of a technical prob-lem than the fossa ovalis defect, having no inferiorseptal margin and sitting astride the orifice of theinferior vena cava with intimate relationships tothe valve of the inferior vena cava and the rightinferior pulmonary vein orifice.These defects are liable to be incompletely closed

at the lower end, or when sutured under tensionthe repair may disrupt postoperatively. Inaccurateclosure may also produce a diversion of theinferior vena caval blood flow into the left atrium(Fig. 1). Bedford et al. (1957) and Bjork et al.(1958) described the presentation of this compli-cation during or immediately after operation whenhypothermia had been used. More commonly, asdescribed by Effler and Groves (1961) and Must-ard, Firor, and Kidd (1964), there is an apparentlyuncomplicated immediate postoperative course

LAI VC

FIG. 1. Diagram to show how suture of atrial septum tovalve ofinferior vena cava (IVC) deflects inferior vena cavalblood into left atrium (LA).

lPresent address: Wessex Regional Cardiac and Thoracic Centre,Southampton Western Hospital, Southampton SO9 4WQ.

with satisfactory, even dramatic, reduction in heartsize and pulmonary vascularity, only to be fol-lowed by the insidious onset of cyanosis, dyspnoeawith effort, and eventually finger clubbing andpolycythemia.We report and discuss the techniques we have

used to deal with these problems in four clinicalcases.

CASE HISTORIES

CASE 1 J.H., a 26-year-old woman, underwent repairof an asymptomatic atrial septal defect under hypo-thermia at another hospital in January 1964.The secundum defect of inferior vena caval type

measured 6-5 x 3 cm, being an almost total defect ofthe lower interatrial septum. The immediate post-operative course was uneventful with marked reduc-tion in heart size on the chest radiograph, but overthe next few months she complained of dyspnoea onwalking and climbing stairs and thought on severaloccasions that she was cyanosed.

In October 1964, right heart catheterization andangiocardiography via the superior vena cava wereperformed but gave no useful information exceptthat the systemic arterial oxygen saturation was 8700.Over the next three years she consistently complainedof increasing cyanosis and dyspnoea while walking orclimbing stairs but she was able to carry on herfavourite recreation of bell-ringing in the local churchwithout difficulty, an activity which entailed exerciseof the upper limbs only.

In August 1967, another right heart catheterizationwas performed and on this occasion the catheter waspassed from the right long saphenous vein up the in-ferior vena cava. The catheter passed into both rightand left atria and an angiocardiogram showed that

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Complications following closure of atrial septal defects of the inferior vena caval type 755

a b c

FIG. 3. Cannulation of the inferior vena cava using thesaphenofemoral junction: (a) line of incision in stump ofsaphenous vein; (b) cannula in position. In practice thecannula would be larger and would fill the femoral vein;(c) the opened-out stump of the saphenous vein can be usedas apedicledpatch to close the cannulation site and so avoidnarrowing thefemoral vein.

FIG. 2. Case 1. Angiocardiogram. The catheter has beenpassed up the inferior vena cava and its tip lies at theinferior cavo-atrial junction. An injection of contrastmedium has filled the left atrium with reflux into a hepaticvein and the right inferiorpulmonary vein.

TABLEPREOPERATIVE SYSTEMIC 0, SATURATION ON DIFFER-

ENTIAL EXERCISE: CASE 1

02 Content (ml/I) % Saturation

Rest . 136 84-5Leg exercise .. 95 64-55 minute rest .. 129 82Arm exercise .. 124 7910 minute rest .. 125 80

dye passed from the inferior vena cava into the leftatrium (Fig. 2).A differential exercise test revealed a significant fall

in systemic oxygen saturation to 64 5% with leg exer-cise but no significant change with arm exercise(Table)

In January 1968 she was admitted to the NationalHeart Hospital for corrective surgery. On examinationthere was mild cyanosis at rest and mild clubbing ofthe fingers. A short systolic murmur grade I/IV alongthe left sternal edge was the only other abnormalphysical finding. Haemoglobin was 18A4 g%, PCV57%, and total WCC 3,800/mm3. A chest radiographrevealed a normal sized heart with normal pulmonaryvascularity.The heart was exposed by median sternotomy, and

palpation via the right atrial appendage failed toreveal any communication with the inferior vena cavabut the suture line in the septum was easily felt. The

3I

a

'9- I? vCLA 1\%

b

FIG. 4. Reconstruction of atrial septum: (a) the inferiorvena cava has been mobilized and occluded by a clamp. Theprevious suture line in the septum (stippled) has beenreopened and pericardial graft (1) used to reconstruct thelower end of the septum; (b) the broken line indicates howclosure by direct suture produces narrowing at the inferiorcavo-atrial junction. A second graft (2) is used to enlargethis area; (c) graft (2) in position, completing the repair.

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inferior vena cava was cannulated via the femoralvein (Fig. 3) and the superior vena cava wascannulated via the right atrial appendage, andarterial return was into the ascending aorta.Cardiopulmonary bypass was instituted withcooling to 31-5° C and the inferior vena cava wascarefully dissected free down to the diaphragm andoccluded by a clamp instead of a snare, thus avoidingdistortion of the cava. After clamping the aorta, theright atrium was opened longitudinally in the line ofthe previous incision. The atrial septum was incisedparallel to the previous suture line which had inclu-ded a prominent valve of the inferior vena cava,diverting the inferior vena caval blood into the leftatrium. There was not sufficient septal tissue toreconstruct the septum in its correct anatomical planeso a Dacron patch was sutured in so that it redirectedthe inferior vena caval blood forward into the rightatrium and closed the septal defect (Fig. 4a). Somedifficulty was experienced in placing this patch accu-rately because the inferior pulmonary vein lay closeto the line of closure of the septum. The forwardangulation of the Dacron patch produced narrowingof the inferior vena cava/right atrial junction whichhad to be enlarged with a gusset of free pericardium(Fig. 4). There were no complications. She was givenanticoagulants for six months to prevent any thrombusforming on the Dacron patch until endothelializationhad occurred.Two years postoperatively she was pink with a

normal exercise tolerance.

CASE 2 G.P., an 18-year-old boy, underwent repairof an asymptomatic secundum type atrial septal defectunder cardiopulmonary bypass at another hospital inFebruary 1962. The postoperative course was un-complicated.Over the next two years faint central cyanosis was

noticed on exercise, gradually increasing in severityand eventually becoming established at rest. Therewas only mild dyspnoea on walking up hills and stairs.

Examination revealed moderate central cyanosiswith grade 2-3 clubbing of the fingers. There wassinus rhythm with a blood pressure of 130/110 mmHgand no evidence of cardiac failure. The heart wasquiet on palpation and the pulmonary component ofthe second heart sound moved normally with respira-tion; there were no murmurs. A chest radiographrevealed a normal sized heart. The lung fields wereslightly plethoric, but the main pulmonary artery seg-ment was not prominent. Haemoglobin was 22-4 g%'.The electrocardiogram was within normal limits.

In July 1970 cardiac catheterization revealed asystemic arterial oxygen saturation of 80% with nor-mal right and left heart pressures. A catheter passedfrom the inferior vena cava easily into the left atriumand into all pulmonary veins except the left inferiororifice. An inferior vena cavogram demonstrated theinferior vena cava entering the left atrium.He underwent open heart surgery at the National

Heart Hospital in January 1971. Palpation through

the right atrial appendage revealed a small low atrialseptal defect which was too small to accept a cannula.This was the only opening into the inferior vena cava.The right femoral vein was exposed and cannulatedas described previously and the superior vena cavawas cannulated via the right atrial appendage. Theascending aorta was cannulated for arterial returnand the patient was placed on normothermic cardio-pulmonary bypass. The inferior vena cava was dissec-ted free down to the diaphragm and cross-clampedcarefully to prevent distortion. With the aorta cross-clamped the right atrium was opened and the atrialseptum incised upwards from the small residual septaldefect along the line of the original closure. An elip-tical pericardial graft was then sutured into positionso as to deflect the inferior vena caval return forwardinto the right atrium and to close the interatrial sep-tum (Fig. 4). It was necessary to enlarge the inferiorvena cava/right atrial junction with a second peri-cardial graft at the lower end of the incision in theright atrium (Fig. 4).There were no postoperative complications. Two

months postoperatively he was a normal colour andthe finger clubbing was regressing.

CASE 3 Y.H., a 35-year-old woman, underwentclosure of a large secundum type atrial septal defectby direct suture with cardiopulmonary bypass in 1966at another hospital. Previously her only symptom hadbeen tiredness after moderate exertion.

Postoperatively, although initially improved, shesoon complained of dyspnoea with effort again andthe heart failed to decrease in size. On examinationthere was sinus rhythm with a normal blood pressureand a predominant left ventricle. There was fixedsplitting of the second heart sound, a pansystolicapical systolic murmur (grade lI/VI), and a thirdheart sound. A chest radiograph revealed moderatecardiac enlargement and a prominent pulmonaryartery with pulmonary plethora. An electrocardio-gram showed sinus rhythm with a right axis and rightventricular hypertrophy.

Cardiac catheterization confirmed the presence ofa residual atrial septal defect with a pulmonary tosystemic flow ratio of 3 to 1 and mild to moderatemitral regurgitation on left ventricular cineangio-cardiography.

In March 1971, the right atrium was explored withcardiopulmonary bypass and a large residual septaldefect of the inferior vena caval type was found. Theoriginal suture line had torn away. leading to completerecurrence of the defect. The mitral valve appearednormal on inspection and there had been no obviousmitral regurgitation on palpation via the right atrialappendage before bypass.The defect was accurately closed with a Dacron

patch. Postoperatively she received anticoagulants forthree months. Four months postoperatively the hearthas decreased in size and there has been a reductionin pulmonary plethora, but an apical pansystolicmurmur persists with a little prominence of the left

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Complications following closure of atrial septal defects of the inferior vena caval type 757

atrium. It is thought that she has mitral regurgitationdue to prolapse of the posterior mitral cusp.

CASE 4 P.O., a 25-year-old woman, underwent repairof an asymptomatic secundum type atrial septal defectat another hospital at the age of 15 years under hypo-thermia. A large secundum defect low in the atrialseptum was described and the lower margin of thedefect merged with the valve of the inferior venacava. A direct suture closure was performed but wasincomplete inferiorly because of possible stenosis ofthe orifice of the inferior vena cava.On admission to the National Heart Hospital there

were signs of a left-to-right shunt at atrial level and agrade II/IV pansystolic murmur at the apex with aslightly prominent left ventricle. A further cardiaccatheterization revealed a pulmonary systemic flowof 3:1 with mild elevation of the pulmonary arterypressure. A left ventricular angiocardiogram showedan abnormal mitral valve with ballooning of theposterior cusp accompanied by mild mitral regurgita-tion.

In June 1970, under normothermic cardiopulmonarybypass, the right atrium was explored. Before institu-tion of bypass, palpation via the right atrial append-age revealed a low atrial septal defect without a lowermargin and trivial mitral regurgitation without mitralstenosis. On opening the right atrium there was aresidual inferior vena caval type septal defect sittingastride the orifice of the inferior vena cava. The mitralvalve appeared normal except for a redundancy ofthe centre of the posterior cusp with normal lookingchordae. With a dry field using ischaemic arrest theanatomy of the septal defect was carefully identified,and it was closed with a patch of autogenous peri-cardium.

After bypass the left atrial pressure was 9 mmHgwith excellent cardiac function. Six months after sur-gery she was asymptomatic and the heart was con-siderably smaller with reduction in pulmonary vascu-larity. There was still a soft pansystolic murmur at theapex.

DISCUSSION

Rokitansky (1875) first described the anatomy ofthe atrial septal defect lying astride the orifice ofthe inferior vena cava, the defect having no lowerseptal margin, and with the opening of the inferiorvena cava directed partly into the left atrium.

Diversion of the inferior vena cava into the leftatrium complicating closure of these defects wasfirst described by Bedford et al. (1957) when threecases occurred in 61 closures of atrial septal defectby direct suture using circulatory arrest under mild(30° C) hypothermia by surface cooling. Althoughthere have been other reports in the literature(Bjork et al., 1958; Clause et al., 1962; Effler andGroves, 1961; Mustard et al., 1964; Osawa, 1968;Staple, Ferguson, and Parker, 1966), it is known

that many other unreported cases have occurred.All authors have emphasized that if the inferiorvena caval valve is mistaken for the lower marginof the defect and included in the line of sutureclosure, then this complication will occur. Al-though this is more likely under the hurried con-ditions when mild hypothermia is used, thepresence of a venous cannula in the inferior venacava does not guarantee that this accident cannothappen, as is shown by our second case. Distor-tion of the inferior vena caval orifice by a snaremay also lead to inaccurate placement of sutures(Effler and Groves, 1961), and failure to appre-ciate the relationships of the lower edge of theatrial septum to the caval orifice may lead to thesame complication.

Because the anatomy is more complex, the in**ferior vena caval type of defect tends to be in-completely closed more often than other types ofatrial septal defect, leaving a residual left-to-rightshunt. In addition, when a direct suture closure isused, tension is created between the relativelyfixed suture line in the septum and the mobiletricuspid valve annulus. This predisposes to par-tial or complete breakdown of the repair, particu-larly if there is little or no strong tissue along theanterior or medial margin of the defect. For thesereasons it is our practice to close this type of defectwith a patch, preferably of autogenous pericar-dium, inserted in a dry field after accurate identifi-cation of the anatomy. The use of a patch pre-vents tension at the suture line and allows for thedifference in plane between the atrial septum andthe posterior margin of the inferior vena cavalorifice.The occurrence of an inadvertent diversion of

the inferior vena cava into the left atrium maypresent on the operating table or in the immediatepostoperative period with severe cyanosis orhypoxia-induced arrhythmias, as in early reportsby Bedford et al. (1957) and Bjork et al. (1958). Inthese cases there was probably total diversion ofinferior vena caval flow into the left heart. Bothauthors reported successful resuscitation ofpatients by immediate reoperation under hypo-thermia, in one case preceded by emergency angio-graphy, but there was a residual right-to-leftshunt in one case and there were several fatalities.Successful total repair requires a careful reapprai-sal of the anatomy under ideal conditions, but iffacilities are less than ideal, complete reopeningof the septal defect is life saving.

Frequently the diversion is not complete ini-tially, particularly when the inferior vena cava hasbeen cannulated for extracorporeal circulation, a

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small residual defect remaining. The late presenta-tion of this syndrome in our two cases was classi-cal in that there were no immediate postoperativecomplications. Gradually, some months later,dyspnoea and cyanosis on exercise involving thelower limbs but not the arms became manifest,and still later cyanosis at rest. Presumably thisfollowed complete or almost total septal closuredue to fibrosis and contracture of the margins ofthe residual defect. Due to abolition of the left-to-right shunt, serial chest radiographs classicallydemonstrate a dramatic decrease in heart size andpulmonary vascularity with shrinkage of the rightatrium. The diagnosis can be confirmed by rightheart catheterization via the femoral vein andinferior vena cava and may be missed if thesuperior vena caval route is used. Systemic arterialblood samples during exercise of the upper andlower limbs demonstrated the differential oxygensaturation in case 1 (Table). Injection of contrastmedium via an inferior vena caval catheter andangiocardiography in the oblique plane will clearlyshow the abnormality (Fig. 2).

Repair of this abnormality requires a carefullyplanned approach with a dry undistorted field toallow accurate identification of the anatomy. Wehave used a median sternotomy for exposure andnormothermic cardiopulmonary bypass with aperiod of ischaemic arrest. No reliance should beplaced on finding a residual opening between theright atrium and inferior vena cava for cannula-tion and the inferior vena cava should be cannula-ted peripherally via the femoral vein. We havepreferred to use the saphenofemoral junction asa cannulation site and use the saphenous veinstump in the vein closure (Fig. 3). The inferiorvena cava above the diaphragm should be care-fully dissected free before or soon after startingbypass and occluded by a clamp at the level of thediaphragm as a conventional snare causes distor-tion of the inferior cavo-atrial junction and makesthe repair more difficult.The plane of the incorrectly closed septum lies

well forward and to the right so that the graftused in the repair after the septum has been re-opened is angled forwards. This tends to narrowthe inferior cavo-atrial junction, and in both ourcases a gusset was required to enlarge this junc-tion and prevent stenosis (Fig. 4). The septal graft

may be of autogenous pericardium or Dacronfabric, and if the latter is used considerationshould be given to using a short period of anti-coagulation postoperatively to prevent possiblethrombosis on the patch before endothelializationoccurs.The occurrence of mild mitral regurgitation in

cases 3 and 4 due to ballooning of the posteriormitral cusp in systole was probably not due tochance as the association of this lesion and atrialseptal defect has been described by McDonaldet al. (1970). Both patients have residual pan-systolic apical murmurs and the subsequent fateof these valves is unknown, but there has been agratifying decrease in heart size and symptomaticimprovement in both cases since closure of theatrial septal defect.

REFERENCESBedford, D. E., Sellors, T. H., Somerville, W., Belcher, J. R.,

and Besterman, E. M. M. (1957). Atrial septal defectand its surgical treatment. Lancet, 1, 1255.

Bjork, V. O., Johansson, L., Jonsson, B., Norlander, O.,and Nordenstrom, B. (1958). Operation and manage-ment of a case after diversion of inferior vena cava intothe left atrium after the open repair of an atrialseptal defect. Thorax. 13, 261.

Clause, H. C., Sanger, P. W., Taylor, F. H., Robicsek, F.,and Adamov, D. (1962). Unusual complications in openheart surgery. Collected Works on CardiopulmonaryDisease, 5-6, 305.

Effler, D. B., and Groves, L. K. (1961). Pitfalls in surgicalclosure of atrial septal defect based on experience withone hundred and fifteen cases. Cleveland Clin. Quart.,28, 166.

McDonald, A., Harris, A., Jefferson, K., Marshall, J., andMcDonald, L. (1970). Association of prolapse ofposterior cusp of mitral valve and atrial septal defect.Brit. Heart J., 32, 554.

Mustard, W. T., Firor, W. B., and Kidd, L. (1964). Diversionof the venae cavae into the left atrium during closureof atrial septal defects. J. thorac. cardiovasc. Surg., 47,317.

Osawa, M. (1968). Diversion of the inferior vena cava intothe left atrium after repair of atrial septal defect asso-ciated with partial anomalous venous drainage. Jap. J.thorac. Surg., 21, 127.

Rokitansky, C. (1875). Die Defecte der Scheidewdnde desHerzens. Braumuller, Vienna.

Staple, T. W., Ferguson, T. B., and Parker, B. M. (1966).Diversion of the inferior vena cava into the leftatrium following atrial septal defect closure. Amer. J.Roentgenol., 98, 851.

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