Friday, February 01, 2013


The RAAS system is a very important system in our human body and with the Autonomic Nervous system, probably acts as our body's main physiological compensatory in times of stress and acute / chronic upsets. It adjust fluid volumes and cardiac output. By so doing effects renal and cardiac functions profoundly. Blocking the RAAS by using targetted drugs like ACE-I and ARB seems attractive, but allows little room for the body to "adjust to survive". It is therefore, not surprising that there are now many meta-analysis and trials which warns us against doing that. NEVER ACEI AND ARB TOGETHER.
The latest meta-analysis to join this bandwagon is the meta-analysis by Dr H Makani of St Luke's, New York. Their paper entitled " Efficacy and safety of Dual Blockade of RAAS. A meta-analysis of RCT " was published in the BMJ Jan 28th. They reviewed 33 RCT ( Randomised Clinical Trials ) involving 68,405 patients with a minimum of 1 year follow-up. They involved CCF patients and hypertensive patients.
They concluded that after 1 year, with dual blockade, the group that had CCF had 18% fewer hospitalisation  when compared with the group without CCF. However, this came at a cost of a 55% increase incidence of hyperkalemia, 66% increase in hypotension, and 41% increase incidence of renal failure, with usage of dual RAAS blockage. telling us that there may be some benefit but certainly a lot of potential harm.
In my practice, I do not ever remember dual blocking. To me, it is anathema.
However, I also made a few observations from the paper, which were not said.
1. There is no mention of dual or triple blockage using the new renin inhibitor, Aliskerin, from Novartis? What happens when you triple block with Renin inhibitor, ACEI and ARB, or any 2 of the 3?
2. I am also very curious as to what JNC - 8 for hypertension, will say? We are all awaiting the release of JNC-8 for quite along while now. It has been postponed and postponed, long over due.
3. We must always maintain a healthy balance of the body's compensatory mechanisms. Too much of interference with any one system is bad.

No comments: