Even Small Blockage Can Cause Heart Attack

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Smaller plaques in the coronary arteries are more dangerous than larger blockages. It is wrong to assume that larger the blockage, greater the chance of getting a heart attack.

The larger blockages often cause symptoms of angina chest pain as the heart does not get enough blood when the patient exerts but this usually does not end up in a heart attack. Heart attack often occurs in an otherwise perfectly healthy individual suddenly and manifests either as massive heart muscle damage or sudden cardiac death. These patients often deny history of angina pain prior to heart attack. The average blockage that causes heart attack is less than 50% obstruction in the coronary artery. Patients with severely blocked arteries (a blockage of more than 70%) often do not end up with a massive attack.

So, if severe narrowing of an artery is not the cause of heart attack than what is it? The answer lies not on the severity of blockage but on the nature of the blockage. Blockage is formed due to a plaque. Plaques are a mixture of cholesterol, fat, fibrous tissue and white blood cells deposited in the walls of the arteries over a period of time. These deposits can vary in consistency and their proneness to rupture.

If the consistency is hard, the plaque is called as stable and if the consistency is soft and the plaque is prone to rupture, it is called as an unstable plaque. An unstable plaque irrespective of the amount of blockage is the one which is responsible for acute heart attack. A stable plaque no matter what amount of blockages it is causing is often not the cause of acute heart attack.

In a stable plaque the slow rate of growth of the blockage allows time for blood flow to develop into new arteries called collateral vessels. These new vessels bypass the blocked artery and bring the necessary blood and oxygen to the heat muscle. In some patients the arteries may become completely blocked and yet the heart muscle supply may remain normal because the collateral vessels have enough time to grow.

In an unstable plaque, with the rupture of the plaque, an acute clot forms, and as there is not enough time for the collaterals to develop the patient develops acute muscle damage or sudden cardiac death.

High blood pressure, high cholesterol, active and passive smoking are few of the factors which makes plaques more vulnerable to rupture. Other causes are negative thoughts, deep frying food etc. All these are responsible for generation of free radicals in the body, which makes the cholesterol more sticky and makes the plaque vulnerable to rupture.

These plaques which are often small can rupture suddenly and without warning. Typically such patients may have been feeling themselves perfectly healthy, their treadmill may have been negative, they may have been walking a mile a day for years together without experiencing any chest pain. Until the moment of rupture of the plaque and causation of heart attack these patients might have been absolutely normal.

Even otherwise healthy individuals can develop acute heart attack. The only answer is two-fold either to recognise the underlying risk factors which can be responsible for causation of heart attack and modify them in time or identifying the warning signals of heart attack well in time so that in case of acute heart attack the clot can be dissolved with clot dissolving therapy with reduction of mortality by 30% provided the clot dissolving therapy is started within 3 hours.

The public must know the warning signals of heart attacks and reach the hospital within 3 hours. These are uncomfortable pressure, fullness, squeezing or pain in the centre of the chest lasting more than a few minutes; pain spreading to the shoulders, neck or to the arms; and chest discomfort with light headedness fainting, sweating, nausea or shortness of breath.

Every individual in the coronary age group most have their risk factor evaluation. Risk factors like high cholesterol, high blood pressure, uncontrolled diabetes, excessive negative stress and passive or active smoking if present must be modified well in time. The; main stray of treatment now a days is towards reduction of levels of cholesterol in the blood. Reduction of cholesterol in the blood also reduces levels of cholesterol in the plaque making them more stable.  They highlighted that 1% reduction in the blood leads to 2% reduction in the risk of getting a heart attack.