General practitioners are well-placed to diagnose and manage most cases of renovascular hypertension, though some may benefit from shared care with a specialist. Find out how SingHealth can work with GPs to provide the best care for patients.
General practitioners (GPs) in Singapore are well-placed to diagnose most cases of renal artery stenosis and manage renovascular hypertension through medical therapy. A subset of patients may benefit from shared care with a specialist, and other treatment options including angioplasty and revascularisation therapy. Find out how we can work closely together with GPs to provide the best care for patients.
INTRODUCTION
Renovascular disease is one of the most common
potentially correctable causes of secondary hypertension
and often leads to resistant hypertension.
Renovascular hypertension is a result of reduced
renal perfusion from renal artery stenosis (RAS)
and subsequent activation of the renin-angiotensin-aldosterone
system (RAAS). RAS can progress and
cause ischaemic nephropathy from a chronic reduction
in glomerular filtration rate.
Most cases of renovascular hypertension are caused
by atherosclerosis, followed by fibromuscular
dysplasia (FMD).
PREVALENCE OF RENOVASCULAR
HYPERTENSION
The incidence of renovascular hypertension varies
by clinical setting. It accounts for less than 1% of
mild-to-moderate elevations in blood pressure.1 Its prevalence is much higher in patients with acute,
severe or refractory hypertension.2 This often occurs superimposed upon cases with pre-existing
hypertension.
PATIENT PROFILE AND SYMPTOMS
Patient profiles
Cases caused by atherosclerosis
Atherosclerotic renovascular disease is more common
in patients with pre-existing atherosclerotic conditions
such as coronary or peripheral arterial disease, and
usually involves the aortic orifice or the proximal main
renal artery.
Risk factors for atherosclerotic disease are often
present, such as hyperlipidaemia, cigarette smoking
and an age of over 55 years.
Cases caused by fibromuscular dysplasia
In contrast to atherosclerosis, FMD usually occurs in
young women (< 35 years of age) presenting with an
abrupt onset of hypertension, and typically involves
the distal main renal artery or the intrarenal branches.
Symptoms
Clinical features suggestive of renovascular disease
are described in Table 1 below.
| 1. Unexplained creatinine elevation and/or acute
and persistent elevation in serum creatinine
of at least 50%, after administration of
angiotensin-converting-enzyme (ACE) inhibitors
or angiotensin receptor blockers (ARB) |
| 2. Moderate-to-severe hypertension in a patient
with diffuse atherosclerosis, a unilateral small
kidney or asymmetry in kidney size of > 1.5 cm
that cannot be explained by another reason |
| 3. Moderate-to-severe hypertension in patients
with recurrent episodes of flash pulmonary
oedema |
| 4. Onset of hypertension with blood pressure
> 160/100 mmHg after the age of 55 years |
| 5. Systolic or diastolic abdominal bruit |
Table 1
EVALUATION AND DIAGNOSIS
Routine testing for renovascular disease may
not change its management as current available
evidence suggests that medical therapy may be
as beneficial as invasive procedures, especially
for those with atherosclerotic renovascular disease.
However, renal artery imaging should always
be considered in young patients with resistant
hypertension, and if clinical suspicion for FMD
is high.
Renal Doppler ultrasonography
Renal Doppler ultrasonography is a reasonable
imaging modality as it is relatively inexpensive,
non-invasive and does not involve administration
of contrast.
Magnetic resonance or computed tomography
angiography has higher diagnostic utility,
but are potentially harmful in patients with
advanced chronic kidney disease given the
risk of contrast nephropathy and gadolinium-induced nephrogenic systemic fibrosis.
A stenosis > 75% in one or both renal arteries or
> 50% with post-stenotic dilatation suggests the
diagnosis.
Renal intra-arterial angiography
Renal intra-arterial angiography is the gold
standard.
It can be considered if other non-invasive tests
are negative, clinical suspicion is high, and for
patients on whom a corrective procedure will be
performed if renovascular disease is detected
or progresses.
It is not recommended as a routine test due to
adverse risks such as contrast nephropathy and
cholesterol emboli. It should not be done for
those who respond well to medical therapy or
are less likely to benefit from revascularisation (e.g., patients with advanced chronic kidney disease).
TREATMENT OPTIONS BY GPs
Medical therapy
Medical therapy is the first-line treatment approach to
atherosclerotic renovascular hypertension. This includes
the correction of modifiable cardiovascular risk factors such
as hypercholesterolaemia, smoking and obesity.
Often, multiple antihypertensives are required. The use of
ACE inhibitors or ARBs is recommended to counteract the
inappropriately overactive RAAS.
Kidney function should be checked two weeks after the
addition of an ACE inhibitor or ARB to ensure that the
serum creatinine does not increase, and the ACE inhibitor
or ARB can be continued if there is a < 25% rise in the
serum creatinine from baseline.
WHEN TO REFER FOR SPECIALIST CARE
GPs may be the main party involved in diagnosing renal
artery stenosis.
Referral to specialist care may be considered for patients
with RAS and the clinical features described in Table 2,
where a multidisciplinary team consisting of a nephrologist,
cardiologist and interventional radiologist can help with management.
1. A short duration (weeks or months) of blood pressure elevation prior to the diagnosis of renovascular disease (even if the blood pressure can be controlled with drug therapy) |
| 2. Intolerance to optimal medical therapy (e.g., a clinically significant rise in serum creatinine after initiation of ACE inhibitor or ARB) |
| 3. Progressive deterioration in renal function that is thought to be a consequence of bilateral renovascular disease |
| 4. Progressive deterioration in renal function that is thought to be a consequence of unilateral stenosis affecting a solitary functioning kidney |
| 5. Recurrent flash pulmonary oedema and/or refractory heart failure |
| 6. Suspected fibromuscular disease in a young person |
Table 2
TREATMENT OPTIONS BY SPECIALISTS
Revascularisation therapy
Revascularisation therapy with percutaneous angioplasty
with or without stenting of the renal artery is
second-line therapy.
A recent meta-analysis of nine randomised controlled
trials concluded that renal artery angioplasty did not confer additional benefits above optimal medical
therapy in patients with atherosclerotic renovascular
disease, except in cases of refractory hypertension.4
Candidates for revascularisation should be carefully
selected (see Table 2 for indications to consider
revascularisation).
Angioplasty
As the pathophysiology of FMD is different compared
to that of atherosclerotic renovascular disease,
angioplasty is a therapeutic option for such patients.
Studies have suggested that angioplasty alone may
improve blood pressure and even cure hypertension.
Surgery may be indicated in very selected patients
who have complex anatomic lesions (e.g., multiple
small renal arteries, failed previous endovascular
treatment).
Figure 1 Arteriogram showing a focal stenosis of the left renal artery with post-stenotic dilatation (indicated by the arrow)
Figure 2 Arteriogram after a percutaneous angioplasty has largely corrected the stenotic lesion in the right renal artery (indicated by the arrow)
SHARED CARE – THE GP'S ROLE IN TREATMENT
Pre-care
GPs in Singapore are well-placed to manage
hypertension. A subset of patients with renovascular
hypertension may require the multidisciplinary care
that the SingHealth Duke-NUS Vascular Centre
(SDVC) offers.
If a GP feels that their patients require a more
comprehensive approach to managing this condition
(see Table 2), they may refer them to the Centre for
further management.
Ongoing care
The specialists in the SDVC welcome collaboration
with the patients’ GPs to provide the best care
possible. Patients may choose to continue to
follow up with their GP for the management of
other chronic medical conditions such as diabetes, hyperlipidaemia and obesity.
Post-care and shared care
We welcome the opportunity to co-manage patients with GPs, who remain central to their care. It is
common for patients to see specialists and dietitians
at the Centre, while continuing to follow up with their
GPs for other chronic medical conditions.
THE SINGHEALTH DUKE-NUS VASCULAR CENTRE
The SDVC was established in February 2021 to bring
together the strengths of healthcare professionals
from different specialities across SingHealth
institutions.
It aims to provide seamless and holistic care
for patients with vascular diseases related to
disorders of the arteries, veins and lymphatics,
including renal artery stenosis.
The care for a vascular patient is often complex,
and usually involves coordination by the primary
clinician to ensure the patient’s care needs are met.
Many of these conditions can now be managed
by minimally invasive endovascular procedures without the need for open surgery, and many of
these techniques have become the standard of care.
Several specialists including vascular surgeons,
cardiac surgeons, interventional radiologists,
interventional nephrologists and interventional
cardiologists perform endovascular procedures to
treat these conditions.
Our centre collaborates with researchers and
educators from SingHealth institutions and Duke-NUS Medical School to deepen knowledge in the
causes of vascular diseases, drive innovation to
find better ways to diagnose and treat conditions,
and ensure healthcare professionals have the skills
they need to provide the best care for patients.
REFERENCES
- Dworkin LD, Cooper CJ. Clinical practice. Renal-artery stenosis. N Engl J Med. 2009 Nov 12;361(20):1972-8. doi: 10.1056/NEJMcp0809200. PMID: 19907044; PMCID: PMC4812436.
- Textor SC, Lerman L. Renovascular hypertension and ischemic nephropathy. Am J Hypertens. 2010 Nov;23(11):1159-69. doi: 10.1038/ajh.2010.174. Epub 2010 Sep 23. PMID: 20864945; PMCID: PMC3078640.
- Chen Y, Pan H, Luo G, Li P, Dai X. Use of percutaneous transluminal renal angioplasty in atherosclerotic renal artery stenosis: a systematic review and meta-analysis. J Int Med Res. 2021 Jan;49(1):300060520983585. doi: 10.1177/0300060520983585. PMID: 33478308; PMCID: PMC7841243.
Dr Pang Suh Chien is a Consultant at the Department of Renal Medicine, Singapore
General Hospital with an interest in interventional nephrology. She has been a care team
member of SingHealth Duke-NUS Vascular Centre since February 2021.
GPs who would like more information about this topic, please contact Dr Pang at pang.suh.chien@singhealth.com.sg.
GPs can call the SingHealth Duke-NUS Vascular Centre for appointments at the following hotlines, or scan the QR code for more information:
Singapore General Hospital: 6326 6060
Changi General Hospital: 6788 3003
Sengkang General Hospital: 6930 6000
KK Women’s and Children’s Hospital: 6692 2984
National Cancer Centre Singapore: 6436 8288
