High output heart failure caused by extensive arteriovenous malformation: problems and pregnancy

Abstract

Arteriovenous malformation (AVM) occurring in association with soft tissue and skeletal hypertrophy forms the basis of the Parkes Weber syndrome: a rare congenital angio-osteohypertrophy condition with no obvious racial, gender or geographic preference. Usually in the lower limbs, the AVM can result in a dilated cardiomyopathy due to a high output cardiac state. We describe the case of a 21-year-old woman with an extensive AVM affecting one leg, which included the pelvic vasculature. The case concerns assessment of the current high output “heart failure” and her cardiovascular risk from future pregnancy.

BACKGROUND

Arteriovenous malformations (AVMs) can usually only be treated by excision. When this is not feasible due either to extensive location or involvement of other critical organ systems then options become limited. In the case described, the young woman concerned wanted to become pregnant. This presented her cardiology and obstetric team with a number of potentially life-threatening scenarios that would need to be explained to the patient.

CASE PRESENTATION

A 21-year-old Caucasian female presented for an assessment of cardiac status. She reported shortness of breath on climbing stairs and general fatigue on exertion. Since early childhood it had been noted that her right lower limb was larger than the left. On examination she had a cutaneous naevus over the upper right thigh, buttock and right lower abdomen. The whole right leg was larger than the left (fig 1) and felt hot to touch. Additionally, pupils of both eyes were oval in appearance. Ophthalmic examination confirmed bilateral uveo-retinal coloboma. Cardiovascular examination confirmed sinus rhythm at 80 bpm and normotensive at 110/70 mmHg. On auscultation, there was a grade 3/6 systolic murmur audible throughout the precordium. Bruits were audible throughout the right lower limb as far distal as the right foot.

Figure 1.

Frontal view of both lower limbs showing the disparity in size. The patient is wearing a tight support stocking on the whole of the left to both compress the limb and to protect the skin from trauma.

Past history included recurrent episodes of cellulitis of the right leg and extensive arterial bleeding from ulceration. At age 10 years, surgery was performed on the right knee to slow growth of the leg. At the age of 16 years, intractable bleeding from vessels over the right shin required surgical intervention. There is no family history of AVMs, although her mother also has bilateral uveo-retinal coloboma.

INVESTIGATIONS

The plasma brain natriuretic peptide level in our patient was 7 μmol/L (normal range for a woman of this age is 0–4 μmol/L). MR-angiography has shown that the arterial system in the right leg is dilated with a markedly distended venous system extending to the right calf and proximally to the right iliac and pelvic veins. The vasculature in both the thigh and calf is in keeping with an extensive AVM. An echocardiogram has shown a dilated left ventricle with dimensions of 63 mm in diastole (normal upper limit 56 mm) and hyperdynamic systolic function. Cardiac output calculations suggest an output of 11.9 L/min and a cardiac index of 6 L/min/m² (normal range 3.7+0.5 L/min/m²). Doppler interrogation of aortic and pulmonary flow demonstrated raised velocities at 2 m/s. Mild mitral regurgitation was present into an already enlarged left atrium at 52 mm (normal range 25–41 mm). The mitral E:A ratio (1.98) and mitral valve deceleration time (169 ms) were normal.

TREATMENT

Management has included compression stockings to reduce oedema and provide protection from trauma. Regular cardiological assessment has included echocardiographic monitoring of her dilated cardiomyopathy.

OUTCOME AND FOLLOW-UP

When last reviewed, the patient had become pregnant and is now under shared care with a tertiary cardiac centre and major obstetric unit that specialise in the management of complex obstetric situations. How the pregnancy and delivery are managed will depend on changes that occur in the AVM and the cardiac response to any haemodynamic shifts.

DISCUSSION

AVM occurring in association with soft tissue and skeletal hypertrophy forms the basis of the Parkes Weber syndrome: a rare congenital angio-osteohypertrophy condition with no obvious racial, gender or geographic preference.¹ Patients with Parkes Weber syndrome (PWS) generally do well although the high output cardiac status can cause heart failure. In a series of twenty-eight patients reported with PWS, five required orthopaedic surgery to correct leg length discrepancy, three required amputation of a limb, six had signs of cardiac enlargement and one patient died of cardiac failure.² Differentiation from the similar condition of Klippel Trenaunay syndrome (KTS), in which only the veins and lymphatics are involved, can be difficult. Both conditions can result in limb hypertrophy, but in KTS blood flow is sluggish whereas in PWS the arteriovenous fistulae result in high flow.

In our patient, the predominant complications have been wound healing, infections and profuse local haemorrhage. Hypertrophied limbs with such associated complications are often extremely painful. Lymphatic involvement can contribute to the problems with wound healing and swelling due to lymphoedema. A further complication is the potential for pulmonary embolism. Less frequently, the haemangiomas associated with PWS can cause a consumptive coagulopathy due to platelet sequestration (Kasabach Merritt syndrome), which further exacerbates bleeding problems.

Vascular surgical intervention may be appropriate although in the case we describe the AVM was so extensive as to prevent a complete excision. Other methods of treatment include embolisation, sclerotherapy and local or endovascular laser treatment but all require considerable expertise. Low dose aspirin is usually recommended unless bleeding has been problematic. Psychological support may be necessary due to the cosmetic effects of this syndrome.

In our case there was no family history of AVMs, although familial cases have been described.³ Ocular lesions have been described in KTS as have patients who have also had the more widely recognised Sturge-Weber syndrome.⁴ Occular coloboma are not a feature thus far described in the literature as having an association with PWS.

One of the main issues has been discussion concerning the safety of any pregnancy. Due to the progestogenic effects of pregnancy, the AVM might develop to involve any part of the gynaecological circulation, although MR-angiography has shown that the uterine vasculature is not overtly involved. There remain issues about the haemodynamic effects of an increased vascular volume on an already dilated cardiomyopathy. Management of a high output cardiomyopathy can only be achieved through treatment of the source of the condition. Thromboembolic events are a risk (particularly pulmonary) as is the potential for bleeding from coagulopathy. The mechanical effects resulting from the pressure of a gravid uterus will also exacerbate venous pressures in the affected limb and pelvis. Should caesarean section be necessary, it might risk torrential bleeding from engorged venous sinuses around the uterus, resulting in the need to perform a caesarean hysterectomy and consequent risk of maternal mortality from bleeding.

Finally, the uncertain genetic inheritance of this condition means that no estimate can be made of the risk of any baby having a similar condition.

LEARNING POINTS

• MR-angiography is useful in Parkes Weber syndrome to demonstrate deep seated pelvic, abdominal or thoracic vascular abnormalities.

• Bleeding is a major issue that should also prompt investigations to check for an associated consumptive coagulopathy.

• Consider the potential for thromboembolism and particularly pulmonary emboli.

• Thrombotic risk, anticoagulation, pregnancy and oral contraception require multi-disciplinary evaluation in young women who might want to plan a pregnancy.