Monday, November 21, 2011

CORONARY RISK FACTORS AND DEATH FROM FIRST HEART ATTACK.

The 16th Nov 2011 issue of the Journal of the American Heart Association carried a very interesting article. Dr John Canto and colleagues from the Watson Clinic, Lakeland Florida, took a look at the National Registry of Heart Attacks, from 1994-2006. They found about 500,000 patients who had suffered their first heart attack. They were looking into correlating coronary risk factors and heart attacks, and also heart attack survivors. Now 500,000 is a very large number and will surely give much information.
First they found that 85.6% of the heart attack patients had one or more major coronary risk factors. Only 14.4% had no coronary risk factors. The most common coronary risk factor was hypertension ( 52.3% ). Smoke ( 35.3% Lipids ( 28% ), Family History, defined as one relative <60years with a heart attack ( 28% ) and T2DM ( 22.4% ).
What is even more interesting is that those patients with more coronary risk factors do better following their first heart attack. Those with no or less coronary risk factors do worse.

Risk factors, n
In-hospital mortality, % of patients
0
14.9
1
10.9
2
7.9
3
5.3
4
4.2
5
3.6

Dr Canto and colleagues also found that compared to patients with all 5 coronary risk factors, those with no coronary risk factors have a 54% chance of dying from their first MI after adjusting for all the other confounding factors. This is also interesting.
How does one explain these findings? Is it that those with more risk factors are already under medical treatment and supervision, more likely to be on aspirin and also statins? or more likely to have collaterals, or chronic stenosis which induces ischemic pre-conditioning? and so promotes better survival? Obviously, much more work needs to be done in this area.
Don't get me wrong, I am not asking that we should all go out and abuse ourselves to increase our lipids and get hypertension and diabetes. I am just highlighting an interesting clinical observation. Remember, this is a registry and so not confirmatory and gospel truth. It just helps us to understand things a bit better.
Yes, sometimes coronary risk factors cannot be avoided, as in hypertension and family history, but those that can be avoided, we must avoid. Obviously, no CAD also means no heart attacks, and that is the better strategy and message.
Well, this is yet another medical paradox. More coronary risk factors, improves survival following a first heart attack.

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