Coronary computed tomography angiography; a fortune teller?

This study assessed the predictive ability of coronary computed tomography angiography (CCTA) for major cardiac events (such as non fatal heart attack, death) over a long term follow-up in patients with suspected coronary artery disease.

Coronary artery disease, characterized by narrowing of the arteries and disrupted blood supply to the heart muscle, is a leading cause of death worldwide. Therefore many efforts have been invested in finding methods that detect coronary artery disease and its causes.

 CCTA is a noninvasive imaging test that looks at the coronary arteries that supply the heart with blood. During CCTA, x-rays pass through the chest and are picked up by detectors in a scanner that produces 3D images on a computer screen. These images enable physicians to determine whether plaque (fatty deposits) or calcium deposits are present in the coronary artery walls, subsequently allowing assessment of coronary artery disease and prediction of future adverse events.

The predictive ability of CCTA for adverse cardiac events over short to intermediate follow-up (2 years) has been shown in several studies. However, long-term follow-up data is very limited. This study assessed the prediction ability of CCTA for adverse cardiac events over a long term follow up in patients with suspected coronary artery disease.

The study enrolled 1,584 patients undergoing CCTA with suspected coronary artery disease. Two major CCTA parameters were defined as predictive of future cardiac events: Coronary artery disease severity was defined and graded by the number of obstructed coronary arteries found in the scan (0 – 3) and total plaque score was defined as the number of coronary artery segments with any narrowing (≥25% of the artery radius) or any type of plaque found by the scan, irrespective of the degree of the narrowing. Cardiovascular outcomes were defined as occurrence of death or heart attack or the need for revascularization (restoration of blood supply to the heart). During an average follow-up of 5.6 years 61 patients (3.8%) suffered death or heart attack and 52 (3.3%) underwent late revascularization (greater than 90 days after the CCTA scan).

The severity of CAD and the total plaque score were good predictors of death, heart attacks and the need for revascularization, with a high probability of concordance (matching) between the predicted and the observed outcomes.

CAD severity was associated with a 59% probability of predicting heart attacks and death, and 65% probability of predicting the need for revascularization.

Total plaque score had a 66% probability of predicting heart attacks and death, and 63% probability of predicting the need for revascularization.

This study concluded that CCTA is a useful tool in predicting cardiovascular outcomes over a long-term follow-up in patients with suspected coronary artery disease.

It is important to state that CCTA carries some risks such as radioactive exposure (dangerous during pregnancy) and allergic reactions to the contrast dye.