Glasgow MRI and Rotablation Study

Overview

Percutaneous coronary intervention (PCI) with adjunctive high speed rotational atherectomy (HSRA) is commonly used to treat complex and calcified coronary artery stenoses. Theoretically, HSRA may have deleterious effects on the coronary microcirculation and result in peri-procedural myocardial infarction (Type 4a MI). This study is assessing the effects of HSRA PCI using serial multi-parametric stress perfusion cardiac magnetic resonance imaging (CMR) (1.5 Tesla MAGNETOM Avanto, Siemens Healthcare). The study will prospectively enrol up to 75 patients (minimum completed cohort of 50 patients) undergoing elective HSRA PCI and performing multi-parametric CMR at 3 time-points: before HSRA, 1 week post-HSRA, and 6 months post-HSRA. Myocardial perfusion will be assessed using pharmacological stress with intravenous adenosine (140 micrograms/kg/min) at each time point. High-sensitivity cardiac troponin (hsTn) and ECGs will be performed post-HSRA.

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. CMR scans will be performed 1 week before, 1 week and 6 months post rotablation. Cardiac troponin and ECGs will be performed post rotablation to determine the incidence of type IV MI.