How plaque rupture in arteries triggers life-threatening events

Heart attacks and strokes often begin with a rupture in the plaque that lines artery walls. This plaque is a mixture of cholesterol, fatty substances and calcium that gradually accumulates, particularly in the arteries supplying blood to the heart and brain.

According to Prof Khawar Kazmi, head of preventive cardiology at the National Institute of Cardiovascular Diseases, plaque rupture is the critical moment when a heart attack or stroke becomes imminent.

When the plaque ruptures, it exposes its inner contents to the bloodstream. In response, platelets — small blood cells responsible for clotting — flock to the site, aiming to seal the rupture. However, this clotting response can quickly turn dangerous, forming a large thrombus (clot) that blocks blood flow in the artery.

If the blockage occurs in a coronary artery, it can halt blood supply to the heart muscle, leading to a heart attack. Similarly, if it blocks an artery supplying blood to the brain, it results in a stroke, depriving brain cells of oxygen and nutrients.

“Plaque rupture often occurs when the stress within the plaque exceeds the strength of its outer fibrous cap, causing it to burst open,” Prof Kazmi explains, adding that several factors contribute to this rupture, including high blood pressure, plaque composition, inflammation, as well as external and internal stressors.

He says that elevated blood pressure increases the tension in artery walls, placing additional stress on the plaque. Over time, this can weaken the fibrous cap and make a rupture more likely.

He maintains that the structure of the plaque itself plays a role. Plaques with a soft, fatty core and a thin fibrous cap are more prone to rupture than those with a thicker cap. These vulnerable plaques lack the stability needed to withstand pressure.

“Chronic inflammation inside the arteries weakens the plaque’s cap. Inflammatory cells release chemicals that thin the cap and make it more susceptible to breaking,” he points out. Prof Kazmi also says that sudden physical or emotional stress, as well as changes in blood flow patterns, can apply pressure on vulnerable plaques, triggering a rupture.

Additionally, acute stress events or overindulgence in a heavy meal can lead to rapid, acute changes in blood flow, further increasing the risk of a rupture in already vulnerable or soft plaques.

He emphasises that the best protection against heart attacks is to prevent plaque build-up in the first place. “Maintaining health and wellness from childhood onward by eating a balanced diet, exercising regularly and avoiding tobacco use are the foundational steps.”

He advises that the earlier these healthy habits are established, the stronger the protection is against heart disease later in life. “Preventive approach should involve a range of lifestyle choices: controlling blood pressure; maintaining a healthy weight; avoiding tobacco products, including smoking and chewing; managing diabetes and keeping cholesterol levels in check.”

He adds that stress and air pollution are additional risk factors that can contribute to plaque vulnerability, and should be actively managed to protect arterial health. Maintaining blood pressure within a normal range reduces stress on arterial walls, lowering the likelihood of plaque rupture. Regular exercise, a balanced diet and limiting sodium intake are crucial steps.

Similarly, a diet rich in vegetables, fruits, whole grains and lean proteins can reduce plaque build-up by lowering cholesterol. He also advises avoiding foods high in saturated and trans fats, which contribute to plaque formation.

He emphasises that physical activity helps regulate weight, blood pressure and cholesterol levels, reducing stress on the arteries, advising to aim for 150 minutes of moderate aerobic exercise or 75 minutes of vigorous exercise each week.

Exercise also combats inflammation, helping keep the plaque’s cap intact. Chronic stress elevates blood pressure and promotes inflammation, both of which can destabilise plaque. Techniques such as deep breathing, mindfulness and regular physical activity can help keep stress in check, Prof Kazmi points out.

He warns that tobacco use — both smoking and chewing — damages blood vessels, promotes inflammation and accelerates plaque build-up. Quitting all forms of tobacco use significantly reduces the risk of plaque rupture and, subsequently, heart attack and stroke.

He also underscores the importance of regular cholesterol checks. High LDL or ‘bad’ cholesterol contributes to plaque build-up, while high HDL or ‘good’ cholesterol helps clear it. Medications like statins may be prescribed to lower LDL cholesterol in individuals at risk. For high-risk individuals, medications like blood thinners and statins may help reduce plaque rupture risk by managing cholesterol and preventing excessive clot formation.

The cardiologist emphasises that these preventive measures are beneficial not only for individuals with heart disease but for anyone with a family history of heart attacks or strokes. Adopting these habits early on builds a stronger foundation for long-term heart and brain health.