Platelets in Myocardial Ischemia/Reperfusion Injury.

Coronary artery disease, including myocardial infarction (MI), remains a leading cause of global mortality. Rapid reperfusion therapy is key to the improvement of patient outcome but contributes substantially to the final cardiac damage. This phenomenon is called "ischemia/reperfusion injury (IRI)." The underlying mechanisms of IRI are complex and not fully understood. Contributing cellular and molecular mechanisms involve the formation of microthrombi, alterations in ion concentrations, pH shifts, dysregulation of osmolality, and, importantly, inflammation. Beyond their known action as drivers of the development of coronary plaques leading to MI, platelets have been identified as important mediators in myocardial IRI. Circulating platelets are activated by the IRI-provoked damages in the vascular endothelium. This leads to platelet adherence to the reperfused endothelium, aggregation, and the formation of microthrombi. Furthermore, activated platelets release vasoconstrictive substances, act via surface molecules, and enhance leukocyte infiltration into post-IR tissue, that is, via platelet-leukocyte complexes. A better understanding of platelet contributions to myocardial IRI, including their interaction with other lesion-associated cells, is necessary to develop effective treatment strategies to prevent IRI and further improve the condition of the reperfused myocardium. In this review, we briefly summarize platelet properties that modulate IRI. We also describe the beneficial impacts of antiplatelet agents as well as their mechanisms of action in IRI beyond classic effects.

Serum Lipoprotein(a) and 3-Year Outcomes in Patients Undergoing Percutaneous Coronary Intervention.

We aimed at addressing the association between serum lipoprotein (a) levels and clinical outcomes of consecutive patients undergoing PCI. We used consecutive patients undergoing PCI at the Heart Center University of Freiburg, Bad Krozingen in Germany between January 2005 and November 2013. A total of 6679 patients (men [n = 5391] and women [n = 1288]) with mean age of 67.5 (± 11.1) years were assessed at baseline and prospectively followed for 3 years. Lp(a) measurement was performed at hospital admission as a routine laboratory parameter. Approximately 30% of PCI patients showed an elevated Lp(a) value of more than 50 mg/dL. In total, 736 Patients died during the follow-up, thereof 189 (11.3%) in the first quartile, 186 (10.7%) in the second quartile, 183 (11.5%) in the third quartile and 178 (10.7%) in the last quartile (P value 0.843 from LogRank test). The MACE rate showed consistent results with 409 (24.4%), 385 (22.1%), 395 (24.7%) and 419 (25.3%) in the different respective quartiles (P value 0.125 from LogRank test). In this large non-selected cohort of patients undergoing PCI followed by moderate intensity statin therapy, higher Lp(a) levels were not associated with worse clinical outcomes during a follow-up of 3 years.

Clinical Outcomes after Additional Dynamic Renal® Stent Implantation for Stent Recoil in Ostial Coronary Lesions.

BACKGROUND: Interventional treatment of aorto-ostial coronary stenoses is limited by stent recoil and suboptimal angiographic results, leading to restenosis and frequent re-interventions. As a potential bail-out strategy for stent recoil, implantation of an additional stent to increase radial force has been reported. Thus, we sought to investigate clinical outcomes after additional implantation of a Dynamic Renal® stent (DRS), a non-coronary; bare-metal stent with very high radial force, in aorto-ostial coronary stenoses. METHODS: Patients treated by implantation of DRSs for stent recoil in the ostial right coronary artery or the left main stem were identified from the hospital database. Baseline clinical and procedural characteristics were compared to patients who underwent re-intervention for in-stent-restenosis in similar segments by either implantation of conventional drug-eluting stents (DES) or paclitaxel-coated balloons (PCB). Clinical follow-ups were performed up to three years following re-intervention with the assessment of death, target lesion reintervention (TLR), and major adverse cardiac events (MACE) as a combination death, myocardial infarction and target vessel revascularization. Kaplan-Meier analyses were performed for event-free survival between the three groups. RESULTS: Between 05/2013 and 07/2019, 28 patients underwent DRS implantation of aorto-ostial coronary lesions. In comparison with 49 patients with DES implantation and 29 patients undergoing PCB treatment, no relevant differences in baseline parameters were identified. Median follow-up was 714 days, with an available follow-up of >1 year after intervention in 82.1% of patients. In the entire study cohort at two years after re-intervention, the TLR rate was 16% (17 patients), the MACE rate 37% (39 patients), and all-cause mortality 9% (10 patients), with no significant differences between the three groups. CONCLUSIONS: DRS implantation for treating stent recoil of aorto-ostial coronary lesions resulted in a high rate of TLR, and was associated with similar risk for death and MACE compared to treatment of in-stent-restenosis with DES or PCB. Randomized, larger comparisons of contemporary DES in patients exclusively presenting with stent recoil are necessary to further define the efficacy and safety of this approach.