PlaqueTec has validated the LBS in two clinical studies and identified biomarkers associated with CAD and response to specific drug treatments.
First in human CE-marking safety trial
The first-in-human study of the LBS was performed at Papworth Hospital, Cambridge, UK. The study was designed to demonstrate the safety profile and correct functioning of the LBS in 30 patients with chronic stable angina (CSA) and acute coronary syndrome (ACS). Investigators used the LBS to sample coronary blood from a non-symptomatic, minimally diseased artery after the symptomatic (culprit) artery had been treated by stenting. The LBS exhibited the same safety profile as conventional imaging catheters such as intravascular ultrasound (IVUS). The LBS met all designated performance criteria and was subsequently awarded a CE mark for the collection of coronary blood samples.
Proof-of-concept clinical study
The first post-CE mark study examined the local collection of plaque-released biomarkers directly from a target vessel in symptomatic patients scheduled to undergo coronary intervention and receive intracoronary stents. Using a highly multiplexed protein assay to analyse the collected blood samples, investigators observed the release of a large number of inflammatory proteins previously linked to the development and outcome of atherosclerosis in the scientific literature.
Significantly, the level and type of biomolecule and the scale of its local release varied greatly according to the clinical condition of the artery sampled, particularly in terms of the timing of sample collection (i.e. before or after the cardiologist used an angioplasty balloon to deliberately rupture symptomatic plaque).
Healthy coronary arteries with minimal signs of plaque (sampled during the first-in-human study) showed no local release of the inflammatory molecules analysed.
Arteries that caused clinical symptoms (i.e. chest pain) and required stenting were found to release a wide variety of biomolecules including those associated with platelet activation, endothelial activity and white cell (monocyte) entry into the plaque – all of these are known to be key causative processes of plaque development. Further, as many as 14 inflammatory biomolecules demonstrated local release even in a group of patients with stable symptomatic coronary disease requiring stenting (i.e., CSA and not ACS) – a condition that was thought to be a relatively non-inflammatory state.
Investigators also used the LBS to sample coronary blood from patients after the deliberate rupture of symptomatic plaque via balloon angioplasty prior to placement of a coronary stent. This event is analogous to the natural rupture of a plaque that causes heart attack.
Analysis of these samples showed a very different biomolecular pattern of release compared with those collected across the intact plaque; in particular, investigators identified MMP-12 and other biomolecules that are known to be located within the necrotic core of the plaque. They also found other molecules associated with lymphocyte and macrophage activity, both of which are key plaque cellular processes.
The data from the three different artery types is displayed graphically below in the form of volcano plots, used to display large numbers of data points. Each dot represents a specific type of inflammatory biomolecule, with the position along the horizontal axis indicating the extent of local release (increasing towards the right) and the position along the vertical axis (increasing towards the top) showing the statistical significance of release for each data point/biomolecule. Dots in the top right-hand corner indicate detected biomarkers.
No other approach has delivered the extent and precision of data that PlaqueTec has discovered. PlaqueTec’s data have been presented at a number of major international CVD conferences such as EuroPCR, TCT and the Vulnerable Plaque Meeting. The study results were recently published in the December 2017 issue of JACC: Basic to Translational Science.