MRI Before and After Coronary Angioplasty With Rotational Atherectomy

High Speed Rotational atherectomy (HSRA) is a technique used during angioplasty in the treatment of calcified coronary arteries. Rotablation debulks resistant calcium in the coronary artery plaque thus facilitating stent deployment and expansion. The atherectomy technique involves a rotating diamond-tipped burr which breaks down the calcium into small particles which are washed forward by the blood flow into the smaller coronary branches supplying the heart muscle. The dispersed calcium particles may block these smaller blood vessels, interrupting blood flow to an extent that may result in heart muscle damage. When this injury becomes detectable clinically, with symptoms, ECG changes and increased troponin, an iatrogenic type IV myocardial infarction (MI) is diagnosed.

Cardiac magnetic resonance imaging (CMR) is the gold standard method for imaging the heart providing detailed information on cardiac function and muscle injury.

This is a prospective cohort observational study of 60 patients undergoing coronary angioplasty with rotational atherectomy.

The aim of the study is to investigate myocardial injury revealed by paired CMR scans before and after rotational atherectomy.

The hypothesis is that following rotational atherectomy, displacement of calcified particles cause microvascular obstruction leading to reduced perfusion. Since myocardial perfusion and pump function are linked, as myocardial perfusion is reduced after atherectomy, so myocardial contractility (i.e. strain) will reduce. In a second analysis, computer modelling will be used to integrate the different types of CMR information to better understand the spatial, temporal and pathological evolution of myocardial infarction (www.softmech.org). The further hypothesis is that despite CMR detectable infarction the incidence of clinical type IV MI will be low.