Postgrad Med J (1990) 66, 834 - 837 © The Fellowship of Postgraduate Medicine, 1990

Missed Diagnosis

Mitral valve prolapse and occult aortic coarctation

Peter Ludman, Magdi Yacoub* and Mark DancyCentral Middlesex Hospital, Acton Lane, London NWIO 7NS, UK.

Summary: A 22 year old man developed symptoms of left ventricular failure secondary to atrialfibrillation and congenital mitral regurgitation. After operation for mitral valve repair he was unable to besuccessfully weaned from cardiopulmonary bypass and this was ascribed to poor left ventricular function.He therefore underwent emergency cardiac transplantation but again was unable to be weaned frombypass. At post-mortem examination a previously undiagnosed aortic coarctation was revealed.The presentation of occult aortic coarctation is discussed, and its association with congenital mitral

valve abnormalities reviewed.

Introduction

The presentation of aortic coarctation may beatypical or obscured by other abnormalities. Itmust, however, be borne in mind in all patients withcongenital heart disease particularly if there areunexpected haemodynamic developments. We re-port a case of occult aortic coarctation whosepresence contributed to peri-operative complica-tions during mitral valve repair.

Case reportA 22 year old man was referred to accident andemergency with a one month history of exertionassociated central chest pain, shortness of breathand palpitations. As a child he had been diagnosedon clinical grounds alone as having a ventricularseptal defect ofno haemodynamic significance, andhe was not followed up. He had been entirely welluntil developing his presenting symptoms.On examination he was not dyspnoeic at rest and

not clubbed or cyanosed. He had an irregular pulse,rate 120/min, blood pressure 110/70 mmHg. Jugu-lar venous pressure was elevated at 8 cm. Leftventricular impulse was displaced to the anterioraxillary line, 6th intercostal space, and wasmarkedly hyperdynamic with a systolic thrill.There was a loud pansystolic murmur radiating tothe axilla. Peripheral pulses were palpable. Res-

piratory system was normal. There was 2cmsmooth hepatomegaly.ECG showed atrial fibrillation, right axis devia-

tion and left ventricular hypertrophy (Figure 1).Chest radiograph showed cardiomegaly, left atrialenlargement and pulmonary venous hypertension(Figure 2). Investigations revealed no evidence ofinfective endocarditis.

Echocardiogram showed a dilated left ventricle(end diastolic dimension 7.5 cm - normal range 3.5to 5.6 cm, end systolic dimension 5.0 cm - normalrange 1.9 to 4.0cm) and a dilated left atrium(5.5 cm - normal range 1.9 to 4.0). There was mildconcentric left ventricular hypertrophy (posteriorleft ventricular wall thickness 1.5cm - normalrange 0.7 to 1.1, interventricular septal thickness1.2 cm - normal range 0.7 to 1.2). Left ventricularfunction was moderately impaired and the anteriormitral valve leaflet prolapsed back into the leftatrium. Marked mitral regurgitation was con-firmed on colour flow Doppler. The aortic valvewas bicuspid with no transvalvar gradient.The patient's ventricular response to atrial fibril-

lation was reduced to 90/min with digoxin, and hissymptoms were relieved. He was referred forreconstructive mitral valve surgery.At operation the mitral valve ring was markedly

dilated resulting in prolapse of the anterior cuspwith elongated chordae. The valve itself was nottypically floppy but appeared to be stretchedsecondary to the annular dilatation. Valve com-petence was achieved by bilateral annuloplasty andfixing part of the anterior cusp to adjoining papil-lary muscle and free edge of the lateral cusp.There were immediate problems coming off

cardiopulmonary bypass. Cardiac output was ex-tremely poor and aortic balloon counter-pulsation

Correspondence and present address: P. Ludman,M.R.C.P., Cardiovascular Unit, Collier Building,Hammersmith Hospital, Ducane Road, London W12OHS, UK.*Present address: National Heart and Lung Institute,London, UK.Accepted: 9 May 1990

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OCCULT AORTIC COARCTATION 835

Figure 1 Electrocardiogram at presentation.

Figure 2 Postero-anterior chest radiograph at presenta-tion

provided no useful augmentation. Persistent hypo-tension unresponsive to inotropic support requiredre-institution of cardiopulmonary bypass whichwas then continued until orthoptic cardiac trans-plantation was performed 2 days later. The newheart was also unable to maintain an adequatecardiac output and became unstable. Attempts atresuscitation failed. Post mortem examination

revealed a preductal aortic coarctation, with thelumen diameter reduced to 6 mm.

Discussion

At presentation as a child with an asymptomaticpansystolic murmur a clinical diagnosis of ventri-cular septal defect was made. In the light ofsubsequent events it is likely that the murmur wasdue to congenital mitral regurgitation. Though norecords are available, it must be assumed thatcomparative measurement ofupper and lower limbblood pressure was not made.At presentation as an adult, peripheral pulses

were palpable but no specific examination forradio-femoral delay was made, nor were upper andlower limb blood pressures compared in spite ofseveral cardiological examinations in two differenthospitals. There were, however, no clinical featuresto suggest that coarctation might be present, apart,perhaps, from the bicuspid aortic valve. Thepatient was normotensive, the loud precordialpansystolic murmur and thrill obscured any othermurmur, the patient had a normal body habituswith no disproportionate limb development. Chestradiograph (Figure 2) did not reveal rib notchingfrom dilated intercostal collaterals, and the aorticarch appeared to be of normal configuration.

The undiagnosed aortic coarctation undoubted-ly contributed to the patient's poor peri-operative

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836 P. LUDMAN et al.

progress. Had the diagnosis been made, the coarc-tation could have been corrected first, so reducingleft ventricular afterload, and hence the severity ofthe mitral regurgitation. The value of mitral valverepair could than have been reassessed. After repairof the leaking mitral valve the left ventricle wasunable to eject the entire stroke volume through thecoarctation. At the time this was attributed to poorleft ventricular function (with inaccurate pre-operative assessment of left ventricular function ina patient with severe mitral regurgitation) and as aresult cardiac transplantation was performed.Failure of the aortic balloon to augment cardiacoutput was due to the presence of a coarctationproximal to the balloon.

Congenital mitral regurgitation is an unusualdisorder and often associated with other congenitalcardiac abnormalities. For this reason pre-oper-ative assessment by cardiac catheter may have beenadvisable. Nevertheless, as the cardiac cathetermight well have been performed from the brachialrather than femoral artery, the aortic coarctationwould have remained undiagnosed unless speci-fically sought.

This case demonstrates how aortic coarctationcan be present in the absence of many of the usualassociated features. Peripheral pulses are frequent-ly palpable in patients with aortic coarctation. In areview of 65 consecutive referrals' in whom adiagnosis of coarctation was later confirmed, 44%had palpable femoral pulses, 16% of which weredescribed as of normal character. In anotherreview,2 25% of patients over 1 year of age hadpalpable femoral pulses. Twenty per cent ofpatients under the age of 19 years and 16% of over19 year olds are normotensive.3 A retrospectiveanalysis of the chest X-ray appearance in 48patients with aortic coarctation revealed it to beabnormal in 92% of cases. The aortic contour wasabnormal in 90% but rib notching obvious in only23%4

Impaired left ventricular function is common inpatients with coarctation. In a study of 11 uncom-plicated patients, all had abnormal left ventricular

function.5 This was attributed to elevated endsystolic wall stress with a resultant increase inmyocardial oxygen demand and impaired earlydiastolic function.Congenital mitral valve anomalies are rare, and

if present are rarely isolated. Coexistent congenitalheart disease is present in 50% to 74%.6'7 There is awell documented association between stenotic leftventricular inflow abnormalities and aortic coarc-tation. In post-mortem studies Becker,8 and laterRosenquist,9 showed a high incidence of (predom-inantly stenotic) mitral valve malformations (26%and 58% respectively) in patients with coarctation.The association between mitral regurgitation

and coarctation is less firmly based. Freed'° notedmitral regurgitation in 18 of 861 patients withaortic coarctation (2.1%). Many had abnormali-ties of leaflets of chordae tendinae. In 15 of the 18patients the aortic coarctation was repaired: 4developed less severe mitral regurgitation, in 7there was no change and 4 deteriorated further.Celano" found echocardiographic evidence of mit-ral valve prolapse in 11.3% ofa series of 56 patientswith aortic coarctation, and 7.5% had mitralregurgitation (all of these showing echocardio-graphic features of mitral valve prolapse).The structural abnormalities of the mitral valve

leaflets and chordae found in patients with mitralvalve prolapse are broadly similar to those de-scribed in patients with mitral valve abnormalitiesand aortic coarctation and as yet there is noevidence for more than a casual associationbetween mitral regurgitation and aortic coarcta-tion. It would seem reasonable to propose that inthe presence of coarctation, any tendency for themitral valve to prolapse may be exaggerated by thehigh left ventricular afterload.The diagnosis ofcoarctation ofthe aorta must be

borne in mind in all patients with congenital heartdisease. Although the presentation of aortic coarc-tation may be atypical or obscured by otherconditions, it can always be diagnosed ifupper andlower limb blood pressures are compared.

References

1. Stafford, M.A., Griffiths, S.P. & Gersony, W.M. Coarctationof the aorta: a study in delayed detection. Pediatrics 1982, 69:159-163.

2. Keith, J.D. Coarctation of the aorta. In: Keith, J.D., Rowe,R.D. & Vlad, P. (eds) Heart Disease in Infancy and Childhood.Macmillan, New York, 1978, pp. 736-760.

3. Borow, K.M. & Braunwald, E. Congenital heart disease inthe adult. In: Braunwald, E. (ed.) Heart Disease, a Textbookof Cardiovascular Medicine. W.B. Saunders, Philadelphia,1988, pp. 976-1008.

4. Martin, E.C., Strafford, M.A. & Gersony, W.M. Initialdetection of coarctation of the aorta: an opportunity for theradiologist. Am J Roentgenol 1981, 137: 1015-1017.

5. Borow, K.M., Colan, S.D. & Neumann, A. Altered leftventricular mechanics in patients with valvular aortic stenosisand coarctation of the aorta. Circulation 1985, 72: 515-522.

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8. Becker, A.E., Becker, M.J. & Edwards, J.E. Anomaliesassociated with coarctation of the aorta with particularreference to infancy. Circulation 1970, 41: 1067-1075.

9. Rosenquist, G.C. Congenital mitral valve disease associatedwith coarctation of the aorta: a spectrum that includesparachute deformity of the mitral valve. Circulation 1974, 49:985-993.

10. Freed, M.D., Keane, J.F., Van Praagh, R., Castenada, A.R.,Bernhard, W.F. & Nadas, A.S. Coarctation of the aorta withcongenital mitral regurgitation. Circulation 1974, 49:1175-1184.

11. Celano, V., Pieroni, D.R., Morera, J.A., Roland, J.-M.A. &Gingel, R.L. Two dimensional echocardiographic examina-tion of mitral valve anomalies associated with coarctation ofthe aorta. Circulation 1984, 69: 924-932.

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