The innovative new ways scientists are tackling high blood pressure – Noted

Drug discord

Hypertension specialist Dr Walter van der Merwe has a number of beefs about the way New Zealand deals with hypertension. He says the condition doesnt get the attention it deserves, and we dont have the right combinations of drugs to treat it.

You dont hear about blood pressure much these days. People talk about cardiovascular risk, cholesterol and statins, but high blood pressure doesnt get very much profile. You dont see public-health posters saying, Have you had your blood pressure checked?

Control of the condition here is poor, says van der Merwe. The most commonly prescribed drug for hypertension is the angiotensin converting enzyme (ACE) inhibitor cilazapril combined with a diuretic, hydrochlorothiazide. Last year, nearly 67,000 people took the drug. ACE inhibitors relax and dilate the blood vessels, making it easier for blood to flow through. Imagine your blood circulation as a garden hose. Weve all put our thumb over the end to create more resistance, increasing the pressure and pushing the water further but the amount of water coming out is a lot less when we apply our thumb. Diuretics increase urination to get rid of extra water and salt so theres less fluid volume and lower pressure in your blood vessels like a tap thats not fully turned on.

The problem in New Zealand, says van der Merwe, is that the cilazapril-hydrochlorothiazide combination has only 12.5mg of the diuretic, and thats too little to be effective. Randomised controlled trials internationally have found that it is no better than cilazapril alone and the combination is not commonly used elsewhere. Overseas, hypertension poly-pills contain up to 25mg of the diuretic. It dates back to whenever Pharmac was first negotiating a package to get an ACE inhibitor, and New Zealand just got stuck with this, says van der Merwe.

When patients blood pressure is not well controlled with that combination, they often end up on two, three or four pills, when the best solution would be a combination pill with double the dose of the diuretic, which is not available here. Also not available here are amiloride tablets. Amiloride is a potassium-sparing diuretic, but Pharmac funds the tablets only in exceptional circumstances, forcing patients to take the only alternative, a fluid that comes in 25ml bottles. If youre prescribed 10ml a day, you end up with all these bottles in your fridge, and if youre going overseas its a nightmare, says van der Merwe. He has put in numerous exceptional-circumstances applications, which have all been declined. Pharmac has said its unable to find a reliable supplier of the tablets, but thats justnonsense.

Phamac told the Listener its sole supplier discontinued the product last year and it was seeking alternative suppliers. It did not answer questions about the strength of the diuretic used in combination with cilazapril, but said the agency funded 40 different drugs for hypertension and does not mandate which medicines are used for which patients under which clinical circumstances. This is a matter for prescribers, with due diligence and professionalism ashealthprofessionals.

Van der Merwe takes issue with the recommended approach of total cardiovascular risk when doctors assess the need for a patient to start anti-hypertension treatment. For example, a 50-year-old woman with a blood pressure of 158/95 wouldnt be treated under current guidelines if she had no other risk factors, such as being a diabetic, smoker or having high cholesterol. The recommended level at which treatment of hypertension should begin regardless of total cardiovascular risk is repeated measurements in the doctors office of 160/100. Her five-year risk of a heart attack or stroke is just 1.7%, and if the risk is under 5%, the benefits of treatment are said to be outweighed by the possible risk. But van der Merwe says a five-year risk is meaningless. A 50-year-old woman now wants and expects to live to her eighties or nineties and to be fit and healthy for all that time. With that blood pressure, her lifetime risk is 50%, and thats what we should be looking at. He says the long-term effect of even moderately raised blood pressure can be severe.

Thats something Auckland car-rental reservation agent and part-time actor and singer Hugh Boyd has discovered to his cost. Boyd, 67, had hypertension for about eight years before he finally agreed to start taking medication in 2015. The doctor would talk to me about it and monitor it and say we should do something about it and I sometimes tried to ignore it. But its not until you realise its a silent killer that you do anything. I didnt want to go on pills you read about the side effects and Id had an allergy reaction to other drugs before. But I dont think I really understood at the start what [hypertension] can do toyou.

In January last year, Boyd was admitted to North Shore Hospital with unstable angina and ended up getting two stents in his coronary arteries. Knowing what I know now, I wouldnt have delayed. Hes now on five drugs a statin, aspirin, an ACE inhibitor, a calcium channel blocker and a diuretic and has had to change two medications when they caused gout and breast swelling.

Van der Merwe believes high blood pressure is unquestionably the biggest cardiovascular risk. Its all about long-term vascular damage and vascular remodelling and I dont like the idea that you might wait before starting treatment. The younger you are, the higher the stakes. A lot of people in New Zealand start treatment only once theyve had a heart attack or stroke, which is putting the cart before the horse. These conditions are preventable if theyre treated in a timelyway.

Ann Bain tries not to let her blood pressure stress her out. Towards the end of our interview, she takes her reading again and its dropped to 161/98 still too high.

Van der Merwe says to get accurate readings on home monitors its important for patients to be on their own in a quiet room, have their arm comfortably supported, with feet on the ground and legs uncrossed. There should be no distractions not even a television, pets or children. Just being with someone and talking will push your blood pressure up.

Bain says although van der Merwe, her specialist, has told her to call him if her reading goes over 170, she doesnt. You cant call him at 2am and say Walter, my blood pressure is 200/100. She says a 24-hour ambulatory monitor found her blood pressure actually went up when she is asleep.It should be 130, but its very rarely that. Its all over the place. And I just dont know why.

*Volunteers interested in taking part in the Auckland study, which is expected to start recruiting later this year, can email James Fisher at jp.fisher@auckland.ac.nz for more information. The investigators will be seeking participants with high blood pressure (patient group) or normal blood pressure (control group), and with no other known health problems.

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The innovative new ways scientists are tackling high blood pressure - Noted