Iron-induced platelet aggregation measurement: a novel method to measure platelet function in stenting for ST segment elevation myocardial infarction

Background Iron and (stainless) steel are potent platelet aggregation activators, and may be involved in stent thrombosis, a serious complication after intracoronary stenting. Current platelet function tests are suboptimal, because of inappropriate agonists and/or lack of reproducibility. We tested the feasibility and reproducibility of a novel platelet function test using stainless steel as an agonist and compared it with other platelet function tests. Materials and methods In 111 patients with acute ST segment elevation myocardial infarction (STEMI), duplo measurements of iron (Fe)‐induced platelet aggregation (FIPA) were performed after clopidogrel, acetylsalicylic acid and/or tirofiban treatment. Within 1 h, citrated blood samples drawn from the femoral sheath before primary percutaneous coronary intervention were added to 100 mg of low carbon steel and after 5 s mixing with vortex, the samples were incubated for 15 min. The ratio between the non‐aggregated platelets in the agonist sample and platelets in a reference sample was calculated as the platelet aggregation inhibition. Results FIPA measurement was highly reproducible (correlation coefficient (R) = 0·942, P < 0·001 between duplo samples). FIPA correlated well with adenosine diphosphate‐induced platelet aggregation (R = 0·83, P < 0·001) but weakly with platelet function analyser‐100 bleeding time (R = 0·56, P < 0·001). FIPA could be measured in patients in which platelet aggregation could not be measured by platelet function analyser‐100 or after adenosine diphosphate. Conclusion This study showed good reproducibility of a novel platelet function test using stainless steel as an agonist and showed correlation with validated platelet function tests. We found that the novel platelet function test is a suitable test for measurement of platelet aggregation inhibition in patients undergoing stenting for STEMI, even when they are taking multiple antiplatelet regimens.