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Plasma free fatty acids to rule out myocardial infarction?
That the release of troponins I and T signals irreversible myocardial injury during myocardial infarction and is an important diagnostic tool is well argued in a recent editorial 1. While their measurement could become a single blood test to rule out myocardial infarction, it is a late diagnostic tool since by then the damage has already occurred: the injured myocardium is their source. In contrast, it is possible to
predict such damage before it is irreversible by measuring part of the systemic response which occurs with the pain and shock (angor animi) of impending infarction. This strategy has been overlooked.
Acute myocardial ischaemia and the onset of acute myocardial infarction is accompanied by virtually instantaneous release of adrenaline which stimulates tissue lipolysis leading to immediate release into plasma of free fatty acids (FFA or non-esterified fatty acids - NEFA) and free glycerol from stored glycerides. Elevation of plasma FFA occurs within the first hour after the onset of pain and shock 2,3.
Furthermore, the extent of elevation provides an index of the gravity of myocardial damage which will occur. Marked elevation of plasma FFA presents the ischaemic myocardium with such an excess that oxidative metabolism can be impaired 4.
Plasma FFA concentrations can now be measured rapidly by kit methods. It should, in my opinion, become part of the first venepuncture in the clinical setting of acute ischaemia, even in the home or transporting ambulance. If there is little or no elevation of plasma FFA within the first 3-4 hours of the apparent onset, the diagnosis of acute myocardial ischaemia is unlikely. This test is more informative and provides earlier data than high sensitivity troponin assays.
The challenge now is to prevent or reduce this elevation of plasma FFA. Nicotinic acid was shown more than 50 years ago to have an instantaneous effect 5 but it is not suitable for patients with developing myocardial infarction because of its vasodilatation and hypotensive actions. Analogues of nicotinic acid with the same rapid inhibition of tissue lipolysis need to be developed and given a formal clinical trial 6: it is entirely possible that the development of myocardial damage can be prevented or minimised.
Michael Oliver, professor emeritus of cardiology, University of Edinburgh.
London E14 8DH. michaeloliver@mac.com
1. Timmis A. A single blood test to rule out myocardial infarction? BMJ 2015; 350:9. (24 January 2015).
2. Oliver MF, Kurien VA, Greenwood TW. Relation between serum free fatty-acids and arrhythmias and death after acute myocardial infarction. Lancet 1968: i; 710-715
3. Tansey MJ, Opie LH. Relation between plasma free fatty acids and arrhythmias within the first twelve hours of acute myocardial infarction. Lancet 1983: ii; 419-422.
4. Oliver MF, Opie LH. Effects of glucose and fatty acids on myocardial ischaemia and arrhythmias. Lancet 1994:343;155–8.
5. Carlson LA, Oro L. The effect of nicotinic acid on the plasma free fatty acids; demonstration of a metabolic type of sympathicolysis. Acta Med Scand 1962: 172: 641-647.
6. Oliver MF. Fatty acids and the risk of death during acute myocardial infarctionClin Sci 2015; 128; 349–355.
Re: A single blood test to rule out myocardial infarction?
Plasma free fatty acids to rule out myocardial infarction?
That the release of troponins I and T signals irreversible myocardial injury during myocardial infarction and is an important diagnostic tool is well argued in a recent editorial 1. While their measurement could become a single blood test to rule out myocardial infarction, it is a late diagnostic tool since by then the damage has already occurred: the injured myocardium is their source. In contrast, it is possible to
predict such damage before it is irreversible by measuring part of the systemic response which occurs with the pain and shock (angor animi) of impending infarction. This strategy has been overlooked.
Acute myocardial ischaemia and the onset of acute myocardial infarction is accompanied by virtually instantaneous release of adrenaline which stimulates tissue lipolysis leading to immediate release into plasma of free fatty acids (FFA or non-esterified fatty acids - NEFA) and free glycerol from stored glycerides. Elevation of plasma FFA occurs within the first hour after the onset of pain and shock 2,3.
Furthermore, the extent of elevation provides an index of the gravity of myocardial damage which will occur. Marked elevation of plasma FFA presents the ischaemic myocardium with such an excess that oxidative metabolism can be impaired 4.
Plasma FFA concentrations can now be measured rapidly by kit methods. It should, in my opinion, become part of the first venepuncture in the clinical setting of acute ischaemia, even in the home or transporting ambulance. If there is little or no elevation of plasma FFA within the first 3-4 hours of the apparent onset, the diagnosis of acute myocardial ischaemia is unlikely. This test is more informative and provides earlier data than high sensitivity troponin assays.
The challenge now is to prevent or reduce this elevation of plasma FFA. Nicotinic acid was shown more than 50 years ago to have an instantaneous effect 5 but it is not suitable for patients with developing myocardial infarction because of its vasodilatation and hypotensive actions. Analogues of nicotinic acid with the same rapid inhibition of tissue lipolysis need to be developed and given a formal clinical trial 6: it is entirely possible that the development of myocardial damage can be prevented or minimised.
Michael Oliver, professor emeritus of cardiology, University of Edinburgh.
London E14 8DH.
michaeloliver@mac.com
1. Timmis A. A single blood test to rule out myocardial infarction? BMJ 2015; 350:9. (24 January 2015).
2. Oliver MF, Kurien VA, Greenwood TW. Relation between serum free fatty-acids and arrhythmias and death after acute myocardial infarction. Lancet 1968: i; 710-715
3. Tansey MJ, Opie LH. Relation between plasma free fatty acids and arrhythmias within the first twelve hours of acute myocardial infarction. Lancet 1983: ii; 419-422.
4. Oliver MF, Opie LH. Effects of glucose and fatty acids on myocardial ischaemia and arrhythmias. Lancet 1994:343;155–8.
5. Carlson LA, Oro L. The effect of nicotinic acid on the plasma free fatty acids; demonstration of a metabolic type of sympathicolysis. Acta Med Scand 1962: 172: 641-647.
6. Oliver MF. Fatty acids and the risk of death during acute myocardial infarctionClin Sci 2015; 128; 349–355.
Competing interests: No competing interests