Atherosclerosis

It begins with injury to the thin lining of an artery, from high blood pressureBlood pressureBlood pressure is the force of blood against the artery walls, written as two numbers in millimetres of mercury: the higher one is the pressure as the heart squeezes, the lower one the pressure as it refills. It varies through the day, so a diagnosis is never made on one reading.Read the full definition, tobacco smoke, high blood sugar or simply time. ldl cholesterolLDL cholesterolLDL cholesterol is the particle that carries cholesterol from the liver out to the tissues and deposits it in artery walls along the way. It is the number that treatment aims at, and lowering it reliably lowers the risk of heart attack and stroke.Read the full definition particles slip into the damaged wall, are oxidised there, and draw in white cells that swallow them and die, leaving a fatty core. The body seals the mess under a fibrous cap. That plaque is the lesion of atherosclerosis, and it can sit there for thirty years causing nothing at all.

Why it matters

Trouble arrives in one of two ways. Slow narrowing starves an organ under load, which is felt as anginaAnginaAngina is chest discomfort that appears when the heart muscle is not receiving enough blood, typically brought on by exertion or emotion and eased within minutes by rest. It is a warning that a coronary artery has narrowed, rather than a heart attack in itself.Read the full definition in the heart, as cramping calf pain when walking, or as failing kidney function. Or the cap tears, the blood meets the fatty core, and a clot forms across the artery in minutes — a heart attack if it is a coronary artery, a strokeStrokeA stroke is a sudden loss of blood supply to part of the brain, either from a blocked artery or a bleed. It is an emergency — treatment works only within a few hours of the first symptom.Read the full definition if it supplies the brain. The plaques that rupture are often not the tightest ones, which is why a person with no symptoms can still have a heart attack as their first sign.

South Asians develop it earlier and at lower cholesterol levels than European populations, so a heart attack in the forties is unremarkable in a Pakistani clinic. The risk factors are the familiar list, and the useful thing about them is that most are modifiable: tobacco in any form including paan and shisha, high blood pressure, diabetesDiabetesDiabetes is a condition in which blood glucose stays too high, either because the body makes too little insulin or because it has stopped responding to it. Pakistan has one of the highest rates in the world, and a large share of people with it do not yet know.Read the full definition, a high LDL, abdominal weight, inactivity, and a family history of early heart disease. A statinStatinStatins are medicines that lower cholesterol by reducing how much the liver makes. They are taken to lower the long-term risk of heart attack and stroke, not to treat a symptom.Read the full definition, blood pressure control and stopping tobacco each measurably slow the process; a plaque already formed rarely disappears, but it can be stabilised so that it does not tear.