Researchers in Canada working on an international study, discovered that the angiotensin-receptor blocker (ARB) telmisartan, a newer type of drug for lowering blood pressure, showed a modest reduction in cardiovascular deaths, strokes and heart attacks in patients with heart problems and diabetes who can’t tolerate the standard and more widely used angiotensin-converting-enzyme (ACE) inhibitors.
The research was led by Drs Salim Yusuf and Koon Teo, professors in the Michael G. DeGroote School of Medicine at McMaster University and clinicians at Hamilton Health Sciences, both based in Hamilton, Ontario. The study was published online in the The Lancet on 31 August, and presented at the European Society of Cardiology Congress 2008 being held in Munich, Germany, from 30 August to 3 September 2008.
ACE inhibitors improve blood flow by widening blood vessels, but about 20 per cent of patients who might benefit from ACE inhibitors can’t tolerate them because of kidney problems, swelling, low blood pressure or cough.
ARB also reduces blood pressure but via a different route; it blocks receptors for the naturally occurring hormone angiotensin II that narrows blood vessels and thereby increase blood pressure.
The researchers reported the results of the TRANSCEND (Telmisartan Randomized AssessmeNt Study in ACE iNtolerant subjects with cardiovascular Disease) study that recruited nearly 6,000 patients in 630 hospitals in 40 countries. The project was sponsored by the makers of telmisartan, Boehringer-Ingelheim, whose headquarters are in Germany.
The patients were all intolerant to ACE inhibitors, and had a history of cardiovascular disease or diabetes with end-organ damage. They were randomized to take either telmisartan or a placebo. Many of the patients were also in receipt of treatments such as statins, anti-platelet agents and beta-blockers and their doctors were free to prescribe other blood pressure reducing drugs.
The results showed that:
- Cardiovascular deaths, heart attacks or strokes were modestly reduced in the group taking telmisartan compared to the placebo group.
- There were fewer hospitalizations among the telmisartan patients, for any cardiovascular reason, compared to the placebo patients.
- Telmisartan was well tolerated, and fewer patients stopped taking telmisartan compared to placebo.
- There were more cardiovascular deaths, heart attacks, strokes or hospitalizations for heart failure among the placebo (17 per cent) than the telmisartan (15.8 per cent) group, but the difference (8 per cent) was not statistically significant (ie it could have been random).
- But, when hospitalization for heart failure was excluded, the difference did become statistically significant (14.8 versus 13.0 per cent, respectively, a difference of 13 per cent).
Yusuf said that the study shows the value of telmisartan as an alternative blood pressure reducing drug, and the result, although modest, is clinically important because of the large numbers of patients who can’t tolerate ACE inhibitors.
“Although the benefit is of moderate size, there is an impact on a range of outcomes including the composite of cardiovascular death, myocardial infarction and strokes, as well as cardiovascular hospitalizations,” said Yusuf.
Teo added that:
“The remarkable tolerability of telmisartan is emphasized by the fact that fewer individuals stop medication if they were receiving telmisartan compared to placebo.”
“Effects of the angiotensin-receptor blocker telmisartan on cardiovascular events in high-risk patients intolerant to angiotensin-converting enzyme inhibitors: a randomised controlled trial.”
The Telmisartan Randomised AssessmeNt Study in ACE iNtolerant subjects with cardiovascular Disease (TRANSCEND) Investigators.
The Lancet, published online, 31 August 2008.
Also presented at European Society of Cardiology Congress 2008.
Sources: McMaster University, Cardiosource.
Written by: Catharine Paddock, PhD