Br Heart J 1992;68:616-8

CASE REPORTS

Pulmonary artery rupture in pregnancycomplicating patent ductus arteriosus

Nicholas J Green, Terence P Rollason

AbstractFatal haemopericardium in a 27 year oldpregnant woman was caused by ruptureof a dissecting aneurysm of the pulmon-ary artery. She had an uncorrected patentductus arteriosus and severe pulmonaryhypertension. The wall of the pulmonaryartery showed atherosclerosis and cysticmedionecrosis.

Department ofPathology,BirminghamMaternity Hospital,Queen ElizabethMedical Centre,Edgbaston,BirminghamN J GreenT P RollasonCorrespondence toDr Nicholas J Green,Department of Pathology,Birmingham MaternityHospital, Queen ElizabethMedical Centre, Edgbaston,Birmingham B15 2TG.

(Br Heart J 1992;68:616-8)

Case reportA 27 year old West Indian woman with a patentductus arteriosus had been clinically well andtook no medication. Cardiac catheter studieswhen she was 13 years old had shown pul-monary hypertension with pressures of 70/40 mm Hg. There was reversal of the shuntduring exercise (right-to-left), indicating thatshe was unsuitable for surgery and thereforethe patent ductus had remained uncorrected.On examination, the apex beat was displaced

laterally to the anterior axillary line and therewere signs of pulmonary hypertension-loudpulmonary heart sound (P2) and a palpablepulmonary artery. There was a long earlydiastolic murmur of pulmonary regurgitationand an ejection systolic murmur. An electro-cardiogram showed evidence of right ven-tricular hypertrophy.Her first pregnancy, when she was 25 years

old, had been uneventful; however, there hadbeen clinical signs of increasing pulmonaryhypertension. At 38 weeks' gestation a normalfemale infant was delivered through the vagina.Immediately post partum the motherdeveloped a pyrexia, which was thought to beendocarditis, and this settled on antibiotics.She was strongly advised to avoid furtherpregnancy.The second pregnancy, two years later, was

progressing well and she was admitted tohospital for bed rest. She died unexpectedly inbed at 33 weeks' gestation.

Figure 1 Necropsyappearance of the heartand pulmonary artery,showing dilatation of themain pulmonary arteryand right ventricularhypertrophy. The probemarks the site ofpulmonary artery rupture.

Necropsy and histological findingsThe body was thin but well nourished (height163 cm, weight 54-6 kg). There was a largehaemopericardium caused by rupture of adissecting aneurysm of the main pulmonaryartery into the pericardial sac at the base of theheart. The main pulmonary trunk was dilatedto 5 cm in diameter and the dissection origin-ated in a raised atheromatous plaque on theanterior aspect of the pulmonary artery 3 cmabove the pulmonary valve (figs 1 and 2). Therewas a large patent ductus arteriosus (diameter2 cm) leading to an aorta ofnormal calibre. Theright ventricle was hypertrophied (100 g). Theleft ventricle including the septum weighed160 g. There was no other gross cardiac malfor-mation.

Histological examination of the main pul-monary artery showed a striking accumulationof alcianophilic mucopolysaccharide in themedia (cystic medionecrosis) (fig 3) with dissec-tion between the inner and outer halves. Therewere also small amounts ofmedial alcianophilicmucin in the aorta. In the lungs there werewidespread severe hypertensive changes withplexiform lesions (plexigenic pulmonaryarteriopathy).No other anatomical or histological abnor-

mality ofsignificance was seen and the fetus wasnormal.

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Pulmonary artery rupture in pregnancy complicating patent ductus arteriosus

Figure 2 Necropsyappearance of the openedmain pulmonary artery,showing atherosclerosis.The arterial dissection isseen in the cut edge of thepulmonary trunk (arrow).

DiscussionPulmonary artery aneurysm is a rare conditionand is invariably associated with pulmonaryhypertension. In a necropsy review of 111cases,' pulmonary hypertension due to cardiacmalformation was present in 66%. Patentductus arteriosus was the commonest singlelesion, occurring in combination with 22% ofaneurysms.

Figure 3 Histologicalsection showing pools ofmucopolysaccharide in themedia of the pulmonaryartery (haematoxylin andeosin; originalmagnification, x 500).

When Coleman et al2 reviewed publishedreports they found only six cases of rupturedpulmonary artery aneurysm associated withpatent, ductus arteriosus alone, in addition totheir own. There have been reports oftwo morecases.3 We identified only one report ofrupturein pregnancy,5 however, this was associatedwith pulmonary infundibular stenosis as well aspatent ductus arteriosus. There is also a reportof a maternal death occurring 17 hours postpartum owing to pulmonary artery dissectionassociated with a patent ductus alone,6presumably precipitated by labour. Our case isthe only report we found of rupture duringpregnancy associated with a patent ductus asthe only anatomical abnormality.

Cystic medionecrosis is usually associatedwith dissection of the pulmonary artery3 as isatheroma and our case is no exception. Indeedboth are known to be related to severe pulmon-ary hypertension.This case emphasises the possibility of

arterial dissection in pregnancy, particularly inthe presence of pre-existing cardiovasculardisease. This association has been well des-cribed previously, in particular by Guthrie andMacLean7 who showed that nine of 57 non-aortic arterial dissections in women occurredeither during pregnancy or shortly afterdelivery.

It is of interest to speculate on the cause ofthe apparently increased incidence of bothsystemic and pulmonary arterial dissections inpregnancy. It has been suggested that theincrease in body water in pregnancy is in parttaken up by connective tissue mucopolysac-charides.8 Robertson pointed out there is noreason why mucopolysaccharides in the vessel

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wall should not be involved in this process9;indeed there is some histopathological evidencethat they are.'0 We suggest that the likeliestcourse of events in our case was cystic medio-necrosis and atheroma, followed by dissectionand rupture. These were consequent upon theincreased cardiac output and exaggeration ofmucopolysaccharide deposition associatedwith pregnancy.

We thank Dr RM Whittington, HM Coroner for the District ofBirmingham and Solihull for permission to report this case.

I Boyd LJ, McGavack TH. Aneurysm of the pulmonaryartery. Am Heart J 1939;18:562-78.

2 Coleman M, Slater D, Bell R. Rupture ofpulmonary arteryaneurysm associated with persistent ductus arteriosus. BrHeart J 1980;44:464-8.

3 Nguyen G-K, Dowling GP. Dissecting aneurysm of thepulmonary trunk. Arch Pathol Lab Med 1989;1 13:1178-9.

4 Sardesai SH, Marshall RJ, Farrow R, Mourant AJ. Dissect-ing aneurysm of the pulmonary artery in a case ofunoperated patent ductus arteriosus. Eur Heart J 1990;11:670-3.

5 D'Arbela PG, Mugerwa JW, Patel AK, Somers K.Aneurysm of pulmonary artery with persistent ductusarteriosus and pulmonary infundibular stenosis. Fataldissection and rupture in pregnancy. Br Heart J 1970;32:124-6.

6 Hankins GDV, Brekken AL, Davis LM. Matemal deathsecondary to a dissecting aneurysm of the pulmonaryartery. Obstet Gynecol 1985;65(suppl):45-8.

7 Guthrie W, MacLean H. Dissecting aneurysms of arteriesother than the aorta. J Pathol 1972;108:219-35.

8 Robertson EG. Oedema in normal pregnancy. J ReprodFertil 1969;9(suppl):27-36.

9 Robertson WB. Uteroplacental vasculature. J Clin Pathol1976;Suppl 10 (Roy Coll Path):9-17.

10 Manalo-Estrella P, Barker AE. Histopathologic findings inhuman aortic media associated with pregnancy. ArchPathol 1967;83:336-41.

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