Vulnerable plaque identification and its importance to patients

Heart disease is the leading cause of death globally, responsible for an estimated 17.9 million₁ lives lost each year and causing 1 death every 34 seconds in the US alone₂. Of note, as the leading cause of death and morbidity, heart disease causes more deaths each year than all cancers combined.

The current diagnostic and treatment approaches for assessing patients with chest pain is primarily focused on narrowing of the coronary arteries which at times lead to invasive procedures like invasive coronary angiography. However, not all invasive coronary angiography is useful and necessary as one US study showed that only one-third of referrals for invasive evaluations of the heart, based on the presence of symptoms, show significant narrowing in coronary arteries₃. It is worthwhile to mention here that one can’t see “vulnerable plaques” (also known as high-risk plaques because of their propensity to cause heart attack if untreated) on invasive coronary angiography, the way it is performed routinely unless more sophisticated techniques such as optical coherence tomography or intravascular ultrasound are used in combination. Unfortunately, the latter adds to the cost, time, and invasiveness and thus risks associated with the procedure.

With the recent advancements in Coronary Computed Tomography Angiogram (CCTA) scans, the detection of these vulnerable plaques is now feasible noninvasively and safely. The identification of vulnerable plaques are important as studies have revealed that up to 50% of individuals who experience heart attack may not have any long-term symptoms₄. Indeed, patients with vulnerable plaques who are at risk of experiencing a heart attack may not have any overt symptoms or complaints. A landmark study by Williams et al₅ has shown that a low attenuation plaque (a key vulnerable plaque component) burden greater than 4% is linked to five times higher likelihood of experiencing a future heart attack. This emphasizes the importance of the evidence that patients with these plaques may benefit from more targeted treatment to improve long-term outcomes.

With the widespread availability of CCTA, physicians now have an opportunity to determine the appropriate treatment pathway at an earlier stage during atherosclerosis process.

So what happens then when a physician detects vulnerable plaque on a CCTA scan?

Many studies would suggest that earlier recognition of vulnerable plaques could potentially change the treatment plan (and thus long-term health outlook) for patients₄; unfortunately, this is currently not happening for many cases as its identification requires expertise and a time-consuming process during CCTA reporting.

After a physician determines a person has vulnerable plaque(s) in their coronary arteries, treatments may vary based on the amount/severity and location of the plaque. Those with limited amounts of plaque or plaques which is not causing significant narrowing, may be offered conservative non-invasive options in the first instance such as:

1. Lifestyle changes: Such as a healthy diet, regular exercise, quitting smoking, and reducing stress.
2. Medications: Depending on the patient’s condition, the clinician may prescribe medications such as statins to lower cholesterol levels and aspirin which thins the blood. Statins work by helping transform high-risk low-density, non-calcified plaques into stable calcified plaques.
3. Close monitoring: If the plaque is not causing any symptoms or even limited symptoms, the clinician may choose to closely monitor the patient’s condition with regular follow-up appointments and periodic assessment.

In severe cases, such as when the plaque is associated with extreme narrowing in the coronary artery, the physician may recommend more invasive procedures such as angioplasty/stenting, or bypass surgery that improve blood flow to the heart.

Most of these treatment plans are individualised for each patient and as further research into the detection AND treatment of these plaques progress, many of these treatments will be enhanced, change or progress.

As coronary vulnerable plaque imaging by CCTA can identify a patient population likely to have a higher risk of heart attack, use of endpoints such as vulnerable plaque could decrease the sample size and cost for clinical trials for drug companies and increase the probability of success for drugs progressing to phase III₆.

In summary, the rapid recognition of vulnerable plaques allows clinicians to act on this information which is expected to decrease the risk of future heart attacks. This approach to non-invasive and point of care solutions, can assist physicians in the detection of these plaques and provide information that may help in further personalising treatment plans.