IN THE old days, if you were unlucky enough to have high blood pressure that did not respond to drugs, doctors could offer only a drastic solution: surgical removal of the adrenal gland that sits on top of your kidney.
It worked to treat uncontrolled hypertension, but was something of a catch-22 situation: the adrenal gland controls your body’s sympathetic nervous system and excretes certain vital hormones. Removal deprives your body of those hormones, including ones required for the "fight or flight" response, and causes imbalances in your endocrine system that predispose you to a host of other health problems.
Now, a new therapy introduced in South Africa promises to change all that. Known as renal denervation, it is a "very targeted intervention", an ablation procedure that involves treating nerves around the two renal arteries with heat, says Pretoria cardiologist Dr Iftikhar Ebrahim.
It is similar to a coronary angiogram, he says, as treatment involves placing a catheter into the femoral artery to gain access to the renal arteries for the ablation.
"The kidneys are the most important organ in your body for blood pressure control and aetiology, " Dr Ebrahim says.
Hypertension is common in up to 50% of the population in sub-Saharan Africa, he says, with resistant cases showing up in 10%-15% of the hypertensive population.
It is one of the major risk factors for heart attacks, stroke and renal failure that are also endemic in South Africa and the region. This makes new approaches to treatment for high blood pressure in general, and resistant cases in particular, ever more necessary, he says.
Data on Dr Ebrahim’s first 12 patients with resistant hypertension who have been treated with renal denervation have been analysed and are so far shown to be "very favourable", with a an average systolic decrease in blood pressure of 18mm/hg, he says.
"Once we’ve done the procedure, patients are down from as many as six meds to three, and their blood pressure is better controlled," he says. "That’s a fantastic result."
Some cardiologists have expressed reservations about the procedure, not only because of its newness, but also because of its price.
Renal denervation costs about R70,000 to R80,000, including hospitalisation and the Symplicity catheter, says Mike Howe-Ely, regional director of Medtronic Africa, the company that has brought the equipment into South Africa.
The company launched the RDN Symplicity System in the country last year without securing private funding, Howe-Ely says, due to the demand to have the therapy available to patients with resistant hypertension.
Certainly, the cost has made funders wary, and only Medscheme, Metropolitan and Momentum so far have agreed to pay for the procedure — for selected patients only.
Dr Ebrahim points out that renal denervation costs the same as a coronary angiogram, and the catheter is the price of two stents. The long-term implications make it worth the cost, he says: "If you can prevent someone getting heart attacks, renal failure and stroke, then it is a cost-effective procedure."
The expense related to the procedure means there is a growing need to define patients suitable for the procedure for reimbursement by funders, say cardiologists in a consensus statement drafted by Prof Lionel Opie, Prof Brian Rayner, Dr Graham Cassel, Dr S Khan, Prof Gavin Norton, Dr Tom Mabin and Dr Rajun Moodley.
The statement provides a list of prerequisites for renal denervation that include patients with uncontrolled hypertension with an abnormal ambulatory BP — defined, according to the South African Hypertension Guidelines 2011, as any of the following: daytime mean BP 135/85 mmHg or nighttime mean 120/70 mmHg. It also includes patients who are taking three or more antihypertensive drugs, one of which must be a diuretic, in the optimal doses, or patients with multiple contra-indications or side effects to drug treatment.
Patients also have to be assessed by a specialist physician, cardiologist, nephrologist or endocrinologist for clinical exclusion of secondary causes of hypertension especially interfering drugs.
Dr Ebrahim says renal denervation therapy is initially being offered only to patients with resistant hypertension — in other words, those who are on "every drug possible, and are still not responding", because in the past doctors had nothing else to offer these patients except an adrenalectomy (the surgical removal of the adrenal gland).
"Now we have something that is much safer and more effective," he says.
The hope is that the therapy will prove useful for moderate cases of hypertension, but that requires further study, Dr Ebrahim says.
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