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The role of interventions in secondary hypertension
Interventional therapies can benefit patients with secondary
hypertension significantly in respect of mortality and quality
of life. Notable causes of secondary hypertension that are
amenable to intervention are coarctation of the aorta and
renal artery stenosis (RAS).
Five percent of hypertension derives from secondary causes,
Prof Ikechi Okpechi from the University of Cape Town told
delegates at AfricaPCR 2016. ‘We need to look for the common
clinical clues suggestive of secondary hypertension and investigate
accordingly. Work-up requires a clear strategy. A patient history
needs to be taken and a physical examination performed.
Twenty-four-hour ambulatory blood pressure monitoring is
necessary to rule out primary hypertension. Only screen where
there is a clinical suspicion and start with simple tests.’
Coarctation of the aorta
This is an important cause of secondary hypertension and one
that is often missed, according to Johannesburg cardiologist,
Dr Jeff Harrisberg. ‘The clinical clue is weak or absent
femoral pulses. The primary treatments are surgery and/or
catheter interventions.’
Indications for coarctation stenting include long-segment
coarctation and associated hypoplasia. Covered stents are
preferred and balloon angioplasty should be avoided, as
it is associated with an uncontrolled response. Possible
complications to be aware of include:
•
dissection, aneurysm and rupture
•
femoral artery damage
•
stent migration
•
cerebrovascular accident or peripheral embolism.
Nice-to-haves when undertaking coarctation stenting
include a biplane cath lab, surgical and ICU back up, general
anaesthesia, percutaneous femoral artery closure devices and
CT angiography. ‘But all of these are not always available
in real-world settings. Minimum requirements are a single-
plane cath lab with accurate measuring capabilities, the full
range of one brand of bare or covered stents, a variety of
appropriately sized balloons and large, long sheaths (12–16
Fr)’, concluded Dr Harrisberg.
RAS
The goal of renal angioplasty and/or stenting for RAS is
to provide renal parenchymal protection while controlling
blood pressure, which can be challenging, and preventing
cardiovascular events. ‘RAS is a relatively uncommon
condition, with an incidence of less than 2%’, said Dr Yemi
Johnson, from Lagos, Nigeria.
Ultrasound can be a useful investigative tool in good
hands, but the healthcare practitioner needs to be trained to
look for RAS. ‘Most instances of RAS are unproblematic, so
we need clear indications to intervene. These include resistant
hypertension, drug intolerance and ischaemic nephropathy.’
Dr Johnson summed up as follows. ‘Renal stenting is a
simple procedure if done properly, certainly simpler than
coronary artery stenting. It has a high success rate and, while
serious complications are possible, these can be prevented
with the correct technique.’
Source: AfricaPCR 2016