Coronary heart disease
Diagnostic procedure in coronary heart disease
Circulatory disturbances of the heart due to narrowing or thrombosis of coronary arteries (coronary heart disease) are the most frequent cause of death in Germany. During a heart attack, the lack of blood supply to the heart muscle due to an obstructed artery leads not only to a loss of pumping function in the affected area, but frequently to serious heart rhythm disturbances and, consequently, to sudden heart death.
For the diagnosis and therapy of coronary heart disease, 650,000 x-ray examinations of coronary arteries (heart catheterisations) were performed in Germany in 2002. The incidence of serious complications was 1.5%, in which the procedure had a fatal outcome for one out of every 1000 patients. About half of the above-mentioned heart catheterisations, or around 325,000 per year, did not reveal findings necessitating treatment of the coronary arteries.
Consequently, there is urgent need for a procedure which is suitable for the reliable exclusion of circulatory disturbances in the heart muscle without placing patients at unnecessary risk. Certain limitations apply to the commonly-used examination methods for the diagnosis of coronary circulatory disturbances, such as stress ECG, stress echocardiography and cardiac scinitgraphy (SPECT):
The stress ECG is insensitive in detection and is not feasible in numerous situations. With echocardiography, some heart regions cannot be displayed. Previous heart attacks are only indirectly detectable via abnormal movement of the heart muscle. Some patients exhibit unfavourable conditions for ultrasound examinations.
The nuclear medical procedures (scintigraphy and SPECT) require the use of radioactive substances and have low spatial resolutions, which makes the detection of circulatory disturbances or scars which do not affect the entire wall diameter of the heart particularly difficult.
Advantages of MRI for coronary heart disease
With heart MRI, both heart function and blood circulation can be assessed at rest and under stress. The MRI stress test takes centre stage. Furthermore, there is no other procedure capable of directly showing scars on the heart muscle with such high sensitivity. A cardiac infarction can be reliably confirmed by MRI and assessed in terms of extent, independent of when the event took place.
Due to its scientifically proven higher accuracy in the detection of heart wall scars and circulatory disturbances, heart MRI, including the stress test, possesses a diagnostic advantage compared with the diagnostic methods described above and can be used in place of these procedures. In most cases it also delivers usable results when the previously mentioned procedures do not yield conclusive results. The MRI stress test can more accurately predict whether an intervention on the coronary arteries (and therefore a heart catheterisation) will be necessary or not.
MRI causes no radiation exposure and is therefore suitable for the therapy and clinical monitoring of coronary heart disease. Restrictions of its use are rare and primarily affect pacemaker wearers.
