P62
Successful Treatment of Early Antenatal Severe Resistant Hypertension by Bilateral
Renal Angioplasty
Sarween N1, Karim A1, Day C1, Knox E4, McCafferty I2, Temperton, D3 and Lipkin G1.
University Hospital Birmingham NHS Foundation Trust, Department of Renal Medicine1Radiology2 and RRPS 3
Birmingham Women’s NHS Foundation Trust, Department of Obstetrics4
Background: Hypertensive disorders of pregnancy are a major cause of significant maternal/fetal
morbidity and maternal/fetal death in the UK. Secondary hypertension if identified before 20 weeks,
classified as chronic, is most commonly of renal origin. Fibromuscular dysplasia (FMD) is the most
frequent cause of renovascular hypertension in women of fertile age and may lead to severe
hypertension during pregnancy. Antihypertensive treatment options are limited due to the
teratogenicity risk posed by some agents. We present a 36 year old identified in early pregnancy with
severe resistant hypertension caused by bilateral FMD. The diagnostic and management challenges
faced by the renal obstetric team are covered and the literature reviewed.
Case: A 36-year-old primigravida with no past medical history was referred to the renal-obstetric
services at 11 weeks gestation with severe hypertension. Mean ambulatory blood pressure (BP) was
180/100 despite maximum treatment dose of nifedipine LA and labetalol, having been unsuccessfully
treated with methyldopa prior to this. Clinical examination was normal apart from an epigastric bruit.
Renal function, ECG, urine protein excretion, plasma renin/aldosterone ratio and urinary
catecholamine study was normal. Renal ultrasound identified a smaller left kidney (bipolar length 10
cm), right kidney (12cm) with a ‘tardus parvus’ Doppler pattern in the left arcuate artery suggestive of
renal artery stenosis (RAS). The likelihood of reaching a stage of fetal viability with severe early
antenatal hypertension was felt to be small. After careful MDT discussion and following detailed
patient consent, covering the risk/benefit ratio to mother and baby, catheter renal angiography was
performed. Radiation dose to the fetus was minimised by reducing the X-ray frame rate, exposure
time and lead screening. The total fetal radiation exposure was 10-20mGy which increases the risk of
childhood cancer by 1 in 600. Selective renal angiography demonstrated classical bilateral renal
FMD; severe left and moderate right renal artery stenosis. Bilateral angioplasty resulted in excellent
immediate results without complications. BP rapidly improved and all antihypertensives were
withdrawn after 2 weeks. She remained normotensive thereafter and had successful delivery at 38
weeks gestation. The patient subsequently had an uncomplicated normotenisve pregnancy and both
children are developing normally.
Conclusions: Reports from the literature of FMD diagnosed in pregnancy are associated with poor
pregnancy outcomes and there are few reports of antenatal angioplasty. FMD is a rare yet important
diagnosis to exclude in women presenting with uncontrolled hypertension before fetal viability. In
highly selected cases where the index of suspicion is high and after careful discussion by obstetrician,
nephrologist, radiologist and radiation protection specialist, renal artery angioplasty can be effective
in controlling BP facilitating a successful outcome. The longer term risks to the child posed by
antenatal radiation are small and are outweighed by the greater and more immediate risk to mother
and child during pregnancy of uncontrolled BP.