Coronary Heart Disease

 

 published August 29., 2002 
Silent microinfarction in a 62 year old subject with normal left ventricular function and coronary bypass grafting one year ago 62 year old male patient, overweight (117 kg), with preserved left ventricular function and triple vessel disease, CABG 09/2001, no cardiovascular symptoms. On a routine check CK was found to be elevated (288 U/L), CK-MB subfraction was normal, Troponin was elevated. The patient was taking aspirin, a statin, an ace-inhibitor, a diuretic and a low dose betablocker regimen. A subsequent single day rest/stress sestaMIBI scan revealed some reduced uptake of the radiotracer in the inferior (attenuation ?) and apicolateral (apical thinning ?) wall, but no ischemia.
Comment: CMR has a high capability to detect even small myocardial infarctions with higher accuracy than myocardial perfusion SPECT or PET. The degree of transmurality is a direct marker of viability and does not require potentially arrhythmogenic dobutamin stimulations. A scar transmurality of > 75% is usually associated with failure of function recovery in the future. In subjects tolerating the magnetic bore, and not having contraindications to magnetic resonance imaging, CMR should be the first choice to define viability in humans.

The LIMA-article in a recent Circulation publication (see below) shows a first generation image resolution. Comparing his images with the new Philips delayed imaging sequences shows, that it is likely that higher image resolution will result in higher accuracy (> 80%, possibly 90%) to predict regions with functional recovery and thus viability.

An other very important field of research is the question of revascularization of extensive myocardial scars, e.g. after anterior myocardial infarction. It could well be, that even small subepicardial layers of viable tissue might increase survival, if blood flow is unhampered. 

The images to the right show a small subendocardial infarction in the posterolateral wall. Images were obtained with a special turbo field echo sequence acquired 20 min after double dose Gd-DTPA injection. LV regional function is preserved within this small infarction.