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AFRICA
hypertensive patients on one to three commonly prescribed
antihypertensive drugs. The first interim analysis documented a
progressive fall in both office and ambulatory BP at three and six
months, compared to sham treatment, respectively.
These studies showed the first biological proof that RD was
effective in lowering BP in humans with or without concomitant
antihypertensive medication, and the pathophysiological
contribution of the renal efferent and afferent nerves in
hypertension was confirmed.
8
This has given many investigators
renewed hope that RDmay have a brighter future in the treatment
of hypertension, but there may be a major shift away from RH.
One of the important outcomes of the RD programme is that
we have come to appreciate the crucial role of non-adherence
to medication as a major contributor to apparent treatment
resistance. RD only offers the BP-lowering efficacy of little
more than one antihypertensive drug,
12
and it can never be the
sole answer to patients requiring three or more medications for
the treatment of severe hypertension. It could be an adjuvant
therapy for true RH, but it must also be appreciated that
patients with true resistance with low renin levels respond to
spironolactone or amiloride.
In the author’s view, indications for RD may be for the
treatment of patients with hypertension with intolerance to
multiple antihypertensives, difficult-to-treat hypertension or
patients with irremediable non-adherence despite extensive
counselling, for example, hypertensive patients with forgetfulness
due to early dementia, resulting in poor adherence.
There are many unanswered questions about RD. There are no
outcome studies showing the benefits of RD on hard CV outcomes
and mortality, although the 10/5-mmHg reduction in BP achieved
by RD is likely to result in a substantial reduction in CV events and
mortality.
13
Afferent and efferent renal nerves also play a crucial
role in CV, metabolic and renal diseases beyond hypertension, and
RD may offer a new interventional treatment option to prevent
heart failure, atrial fibrillation, ventricular arrhythmias, chronic
kidney disease, obstructive sleep apnoea and diabetes.
8
Another unsolved question is to identify those patients
who respond most to RD, as analysis of studies suggests there
are responders and non-responders to RD.
11
This is a critical
question as the estimated cost of RD is in excess of R100 000
and it is really important to ensure success of the procedure.
Further research needs to better define the place of RD.
The SPYRAL HTN-OFF and HTN-ON have presented only
preliminary data and longer-term follow up is required. One
needs to proceed cautiously as RD is not a panacea for the
treatment of hypertension and may have a place in very carefully
selected patients in centres of expertise in the management of
hypertension, backed up by experienced interventionists.
Conclusion
Three recent studies showing the BP-lowering efficacy of RD
have renewed interest in the procedure. Further research is
required to determine an evidence-based role for RD in the
treatment of hypertension and the prevention of CVD.
Prof Rayner has served on an advisory board for Medtronics.
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