Evaluation of Cobalt and Chromium Levels Following Implantation of Cobalt Chromium Coronary Stents: A Pilot Study

Abstract

Large increases in myocardial trace elements may adversely affect metabolism and become detrimental to cardiac function. Percutaneous coronary intervention (PCI) allows for the revascularisation of obstructive coronary artery disease using drug-eluting stents. These stents are comprised of a metallic stent backbone covered in an engineered polymer which delivers a drug over a prescribed period to the vessel wall. Given the potential implications of trace metal accumulation within the myocardium, our goal is to determine if metallic coronary stents are able to cause detectable elevations in serum cobalt and/or chromium levels. This study was a single centre, observational, pilot study with 20 patients who underwent planned PCI with implantation of a cobalt chromium drug eluting stent. Serum blood samples were drawn at baseline prior to PCI, 4hours post-stent deployment and at the time of routine follow-up after PCI. All blood samples were analysed for cobalt and chromium concentrations. The primary outcome of this study was the difference in serum cobalt and chromium levels at routine clinical follow-up. The mean follow up was 64.1±17.3 days. There was no difference in serum cobalt levels when comparing baseline and routine clinical follow up (3.32±2.14nmol/L vs. 3.14±1.00nmol/L, p=0.99) nor in chromium levels (4.24±2.31nmol/L vs. 2.82±1.22 nmol/L, p=0.11). There was also no difference between baseline and 4hours post-PCI serum concentrations. Percutaneous coronary intervention with cobalt chromium coronary stents does not appear to cause an elevation in these trace element serum concentrations.