Advances in Cardiac Imaging and the Implications for Underwriting and Claims
Echocardiography was developed during the 1970s and 1980s and allows clinicians to image the heart. The first “M-mode” images were one-dimensional but this was later supplemented with two-dimensional and colour Doppler imaging as the technology developed. Nuclear imaging, the next development, used radioactive dye to assess the extent of heart disease caused by narrowing of coronary arteries showing areas of the heart muscle that do not have an adequate blood supply.
In recent years, an explosion of advanced heart imaging technologies has entered routine clinical practice: CT Coronary Angiography (CTCA), Cardiac MRI (CMR) and three-dimensional echocardiography (3D echo).
Imaging technology will develop ever greater diagnostic capability in the future. The key is to understand the clinical importance of the information that we obtain from the imaging and how we interpret it in the context of each person and each individual case.
Using 3D echo, clinicians generate a rich three-dimensional image of the heart, allowing them to assess how well it is pumping (ventricular function). 3D echo is especially useful at visualizing the structure and function of the valves that control the direction of blood flow between the four chambers of the heart.
CTCA is useful for finding evidence of narrowing (stenosis) or blockages (occlusion) by plaques forming in the coronary arteries that supply oxygen-rich blood to the heart muscle itself and allow it to function properly. CTCA can assess the amount of calcium deposited in these plaques that contain a mix of fat and fibrous tissue – a marker of the risk of future heart problems. This technology is especially useful, in patients who present with chest pain but who have a low risk of coronary artery disease, as a “rule out” test to ensure that there is no significant narrowing of the coronary arteries.
CMR is a development of MRI technologies used for other organs. Unlike other parts of the body, the heart moves as it beats, and it also moves up and down in the chest during breathing – this brings about additional challenges during imaging. CMR has now become a mainstream clinical investigation tool for a wide range of heart problems.
CMR is especially useful for gauging the function of the right ventricle, which pumps blood to the lungs. By using CMR, it is also possible to see if the heart muscle has thickened (hypertrophy) – often due to conditions such as high blood pressure (hypertension) or abnormality of the heart muscle (cardiomyopathy). Using CMR presents another advantage over other technologies; it can be used to look for focal scarring (fibrosis) in the heart, which is often caused by a heart attack (myocardial infarction).
Although the other tools can infer evidence of a heart attack by showing damage to the heart muscle by looking for impaired contraction of the heart, CMR can directly assess the degree and extent of scarring without having to rely on this assumption. As a result, CMR can be used for finding other diseases that cause fibrosis, such as myocarditis, because the pattern of scarring is different to a heart attack.
CMR is like nuclear imaging: A drug is given to speed up the heart, so that the passage of a dye into the heart muscle over time can be assessed with a series of images. Significant stenosis of a coronary artery will prevent the dye from entering part of the heart muscle properly, and this can be used to assess whether there is widespread disease. CMR offers enhanced image resolution over nuclear imaging, which means it can be used to guide the management of patients with coronary artery disease – whether they’ve suffered a myocardial infarct before or not.
All the recently developed technologies mentioned in this blog – CTCA, CMR and 3D echo – have made early detection of heart disease possible. Doctors can now even determine when a person has had a tiny heart attack, which will help improve mortality rates because of early intervention. This is clearly good news. Nevertheless, it potentially puts a strain on Critical Illness products for which claims are paid upon diagnosis of a heart attack. Standard definitions used by insurers must keep pace with the technological advancements in medicine.