Professor Christian Hamilton-Craig
Shane Warne – one of best cricketers in Australian sporting history – died suddenly while on holiday in Thailand.
He was just 52. Warne was a national and international sporting hero. He played 145 Tests for Australia and 194 one-day internationals, bowled 40,705 balls in Test cricket for 708 wickets at an average of 25.41.
It is understood Warne had suffered chest pains before he left Australia, and it is suspected that he died of a massive heart attack.
What could have been done to prevent this tragedy?
We all know of someone who has suffered a heart attack in middle age.
Some of these people presented to hospital early and were treated with coronary stenting and medication to reopen the artery. Others presented too late – with sudden cardiac death.
Heart attacks are primarily due to the build-up of cholesterol and plaque in the coronary arteries, due to high levels of circulating cholesterol in the blood. This will slowly deposit in the artery wall.
The process begins in late adolescence, as shown in in autopsies on young men who died in the Vietnam war indicating the beginning of fatty streaks in the artery at a surprisingly young age.
Plaque builds up over time slowly, like a pimple in the artery wall, and then begins to harden with calcification. Much like a pimple, this plaque has a cheesy soft centre of cholesterol, with a thin cap, which is liable to rupture causing obstruction of the arteries and so heart attack.
Artery calcification is easily detectable these days; using tests such as a Coronary Calcium Scan, which measures the amount of calcified plaque in the arteries of the heart.
Coronary artery calcium scanning is recommended by the Cardiac Society of Australia & New Zealand and the National Heart Foundation of Australia for identifying patients who are at greater risk of coronary events, in order to initiate appropriate treatment.
A Coronary Calcium Score is a quick and easy test: The patient lies down on a CT scanner, has ECG dots placed on the chest, and a single breath-hold takes pictures the heart, without any need for injections or dye.
The amount of plaque is measured and a calcium score is generated. A score above 100 indicates sufficiently high risk for treatment.
Statin medication acts to effectively lower LDL cholesterol and reduce cardiovascular events, with very minimal side effects. Most patients do not even feel they are taking a medication. Some patients, however, may experience statin-associated muscle symptoms, and the treating doctor can try each of the several statins available in Australia beginning with a low dose. Other cholesterol-lowering therapies are available for those who cannot tolerate statins.
The only downside to calcium scoring in Australia is that Medicare does not currently publicly fund it, primarily because no application has been submitted. This is likely to be done in the near future once there is more evidence from Australian studies demonstrating the efficacy and health economics of coronary calcium scoring in our health system.
In the meantime, it is a user–pays test costing around $100–$150, which is well worthwhile and could be considered as a mammogram of the heart. The radiation dose is low, comparable to mammography.
It should be noted that patients who are already at high risk such as those with diabetes, with known coronary artery disease or who have had stents, or bypass surgery should already be on treatment, and therefore do not need a scan.
It is clear that identification of subclinical (hidden) hardening of the arteries, allows identification of patients, who may not have been aware they were at high risk, allowing for early intervention, appropriate treatment, and ideally the prevention of a Shane Warne kind of tragedy.
(Professor Christian Hamilton-Craig of Noosa Hearts Cardiology is a professor of cardiology at University of Queensland, member of the CSANZ clinical and preventative cardiology Council and was the chief lead author for the coronary artery calcium score guidelines.)
