P2Y12 blocker monotherapy after percutaneous coronary intervention

For secondary prevention of coronary artery disease (CAD) antiplatelet therapy is essential. For patients undergoing a percutaneous coronary intervention (PCI) temporary dual antiplatelet platelet therapy (DAPT: aspirin combined with a P2Y12 blocker) is mandatory, but leads to more bleeding than single antiplatelet therapy with aspirin. Therefore, to reduce bleeding after a PCI the duration of DAPT is usually kept as short as clinically acceptable; thereafter aspirin monotherapy is administered. Another option to reduce bleeding is to discontinue aspirin at the time of DAPT cessation and thereafter to administer P2Y12 blocker monotherapy. To date, five randomised trials have been published comparing DAPT with P2Y12 blocker monotherapy in 32,181 stented patients. Also two meta-analyses addressing this novel therapy have been presented. P2Y12 blocker monotherapy showed a 50-60% reduction in major bleeding when compared to DAPT without a significant increase in ischaemic outcomes, including stent thrombosis. This survey reviews the findings in the current literature concerning P2Y12 blocker monotherapy after PCI.

P4503A multi-site coronary vein sampling study on cardiac troponin T degradation in non-ST-elevation myocardial infarction

Background

High-sensitivity cardiac troponin (hs-cTn) assays have reduced specificity for myocardial infarction (MI). In conditions other than MI, cardiac troponin T (cTnT) elevations have been attributed to small cTnT fragments. In search of improved cTnT assay specificity for MI, determination of the in-vivo molecular appearance of cTnT during MI is pivotal.

Purpose

To determine cTnT composition close to its site of release and during the course of MI by multi-site coronary venous system (CVS) and peripheral sampling.

Methods

Lithium-heparinized (LH) plasma and serum samples were obtained from multiple CVS locations in NSTEMI patients. Additionally, samples were drawn from a peripheral artery and vein followed by collections at 6- and 12 hours post-catheterization. cTnT concentrations were measured using the hs-cTnT immunoassay (Roche). The molecular cTnT composition was determined by gel filtration chromatography and Western blotting in an early and late presenting patient.

Results

CVS hs-cTnT concentrations were 28% higher than in the peripheral artery sample (n=71, p<0.001). In contrast to LH plasma, serum caused pre-analytical cTn T-I-C complex disintegration and cTnT degradation. CVS samples demonstrated presence of cTn T-I-C complex, free intact cTnT, and 29 kDa and 15–18 kDa cTnT fragments in higher absolute concentrations than measured peripherally. While the proportion of cTn T-I-C complex decreased and disappeared over time, 15–18 kDa cTnT fragments increased. Moreover, cTn T-I-C complex was more prominent in the early versus the late presenting patient.

Central illustration

Conclusions

In NSTEMI, cTnT is released as a combination of cTn T-I-C complex, free intact cTnT and multiple cTnT fragments. Over time, the composition of observed cTnT forms changes due to in-vivo degradation. These findings serve as a stepping stone to improve diagnostic accuracy of the hs-cTnT assay for MI.