This is where Skepticism should come into play.
We start as a single cell and live on average 70 years after being born.
Our death rate after the first year is quite low and usually due to bad luck.
Say 2 deaths per thousand per year. At that rate we should live on average 250 years.
But little things get in the way as we age. Fourteen and the mind starts working and some people decide to leave of their own volition. This stays steady at 1 per thousand increasing the rate to 3. Car accidents and activity related problems kick in by 20, Things increase slowly till 55 at a rate of 7 with the consequences of lifestyle choices due to alcohol tobacco, drugs, sex, diabetes, diet, Blood pressure , atheroma and cancer. From then to 70 the rate increases to 20 a year at the turning point. 500 people have gone. But now the rate kicks up steeply until the majority of people die in the next 14 years. the rate going up to 40 people a year at 80.
Cardiovascular disease is the most important cause of death in people over 70 accounting for 50 percent of all deaths, half due to heart attacks, slightly less to strokes then other vessels. Cancer accounts for 30 percent. Infection and Kidney and lung disease a large amount of the rest along with infections often secondary to these preexisting conditions.
Basically we start off with good arteries and we are genetically primed to wear out after 70. The arteries build up atheroma which is a combination of calcification and plaque in the vessel walls. We can hasten the process. Bad dental hygiene causing infection in the blood vessels, smoking, Excessive alcohol, Lack of exercise and obesity. Illness like diabetes and blood pressure.
We can actually measure the development of the atheroma with a High quality CCTA (64-slice and higher) is not only able to provide reliable information on coronary luminal changes, but also has the potential to visualize morphological changes of the coronary artery wall, characterize atherosclerotic plaques and identify non-stenotic plaques which may not be detected by invasive coronary angiography. This showed a significant age related increase in calcification
Of these patients with abnormal changes to the coronary arteries, the number of significant coronary stenosis was directly related to the age group, as less than 15% of patients under 56 years had significant coronary stenosis, but this was increased to 29% and 38% in the age groups of 56–65 years and over 66 years,
Cardiac CT for calcium scoring It has been assumed that measurement of risk factors causal for CAD (e.g. dyslipidaemia or hypertension) would be predictive of coronary events, but the relative hazard ratios of these risk factors are inadequate to accurately predict outcome. Seventy-five per cent of previously asymptomatic patients (men < 55 years, women < 65 years) developing their first MI, would have been ineligible for lipid-lowering therapy prior to the event if assessed with a global risk score.
In four major studies, more than 75% of all hard coronary events occurred in persons classified as low or intermediate risk, and the majority of persons classed as high risk had no coronary events. Risk score assessment alone is inadequate in predicting individual coronary risk.
In contrast, a measure of flow limiting obstruction (with ischaemia testing or CT coronary angiography) is not likely to predict risk.
Sixty-eight per cent of MIs occur in vessels with less than 50% obstruction prior to plaque rupture and thrombosis; and 86% occur in vessels with a less than 70% obstructive lesion (the degree of obstruction required to provoke a positive ischaemia test).Similarly, recurrent MIs are usually caused by a second ‘angiographically minor lesion’ commonly found in patients with a large plaque burden.
44% of individuals had a coronary score of zero. This cohort has such a low long-term risk (99.4% 12-year survival), that any further coronary testing is not required, and interventions like lipidlowering therapy are not likely to alter outcome.
A study of asymptomatic persons with a CAC score of greater than 1000 demonstrated they had a 25% risk of death or MI at one year,