Therapeutic anticoagulation is indicated for a variety of circumstances and conditions in several fields of medicine to prevent or treat venous and arterial thromboembolism. According to the different mechanisms of action, the available parenteral and oral anticoagulant drugs share the common principle of hampering or blocking key steps of the coagulation cascade, which unavoidably comes at the price of an increased propensity to bleed. Hemorrhagic complications affect patient prognosis both directly and indirectly (ie, by preventing the adoption of an effective antithrombotic strategy). Inhibition of factor XI (FXI) has emerged as a strategy with the potential to uncouple the pharmacological effect and the adverse events of anticoagulant therapy. This observation is based on the differential contribution of FXI to thrombus amplification, in which it plays a major role, and hemostasis, in which it plays an ancillary role in final clot consolidation. Several agents were developed to inhibit FXI at different stages (ie, suppressing biosynthesis, preventing zymogen activation, or impeding the biological action of the active form), including antisense oligonucleotides, monoclonal antibodies, small synthetic molecules, natural peptides, and aptamers. Phase 2 studies of different classes of FXI inhibitors in orthopedic surgery suggested that dose-dependent reductions in thrombotic complications are not paralleled by dose-dependent increases in bleeding compared with low-molecular-weight heparin. Likewise, the FXI inhibitor asundexian was associated with lower rates of bleeding compared with the activated factor X inhibitor apixaban in patients with atrial fibrillation, although no evidence of a therapeutic effect on stroke prevention is available so far. FXI inhibition could also be appealing for patients with other conditions, including end-stage renal disease, noncardioembolic stroke, or acute myocardial infarction, for which other phase 2 studies have been conducted. The balance between thromboprophylaxis and bleeding achieved by FXI inhibitors needs confirmation in large-scale phase 3 clinical trials powered for clinical end points. Several of such trials are ongoing or planned to define the role of FXI inhibitors in clinical practice and to clarify which FXI inhibitor may be most suited for each clinical indication. This article reviews the rationale, pharmacology, results of medium or small phase 2 studies, and future perspectives of drugs inhibiting FXI.

BACKGROUND: Results from multiple randomized clinical trials comparing outcomes after intravascular ultrasound (IVUS)– and optical coherence tomography (OCT)–guided percutaneous coronary intervention (PCI) with invasive coronary angiography (ICA)–guided PCI as well as a pivotal trial comparing the 2 intravascular imaging (IVI) techniques have provided mixed results. METHODS: Major electronic databases were searched to identify eligible trials evaluating at least 2 PCI guidance strategies among ICA, IVUS, and OCT. The 2 coprimary outcomes were target lesion revascularization and myocardial infarction. The secondary outcomes included ischemia-driven target lesion revascularization, target vessel myocardial infarction, death, cardiac death, target vessel revascularization, stent thrombosis, and major adverse cardiac events. Frequentist random-effects network meta-analyses were conducted. The results were replicated by Bayesian random-effects models. Pairwise meta-analyses of the direct components, multiple sensitivity analyses, and pairwise meta-analyses IVI versus ICA were supplemented. RESULTS: The results from 24 randomized trials (15 489 patients: IVUS versus ICA, 46.4%, 7189 patients; OCT versus ICA, 32.1%, 4976 patients; OCT versus IVUS, 21.4%, 3324 patients) were included in the network meta-analyses. IVUS was associated with reduced target lesion revascularization compared with ICA (odds ratio [OR], 0.69 [95% CI, 0.54–0.87]), whereas no significant differences were observed between OCT and ICA (OR, 0.83 [95% CI, 0.63–1.09]) and OCT and IVUS (OR, 1.21 [95% CI, 0.88–1.66]). Myocardial infarction did not significantly differ between guidance strategies (IVUS versus ICA: OR, 0.91 [95% CI, 0.70–1.19]; OCT versus ICA: OR, 0.87 [95% CI, 0.68–1.11]; OCT versus IVUS: OR, 0.96 [95% CI, 0.69–1.33]). These results were consistent with the secondary outcomes of ischemia-driven target lesion revascularization, target vessel myocardial infarction, and target vessel revascularization, and sensitivity analyses generally did not reveal inconsistency. OCT was associated with a significant reduction of stent thrombosis compared with ICA (OR, 0.49 [95% CI, 0.26–0.92]) but only in the frequentist analysis. Similarly, the results in terms of survival between IVUS or OCT and ICA were uncertain across analyses. A total of 25 randomized trials (17 128 patients) were included in the pairwise meta-analyses IVI versus ICA where IVI guidance was associated with reduced target lesion revascularization, cardiac death, and stent thrombosis. CONCLUSIONS: IVI-guided PCI was associated with a reduction in ischemia-driven target lesion revascularization compared with ICA-guided PCI, with the difference most evident for IVUS. In contrast, no significant differences in myocardial infarction were observed between guidance strategies.

Atherosclerotic cardiovascular disease is a major health concern worldwide and requires effective preventive measures. Lp(a) (lipoprotein [a]) has recently garnered attention as an independent risk factor for astherosclerotic cardiovascular disease, with proinflammatory and prothrombotic mechanisms contributing to its atherogenicity. On an equimolar basis, Lp(a) is ~5 to 6 times more atherogenic than particles that have been widely associated with adverse cardiovascular outcomes, such as LDL (low-density lipoprotein). Lp(a) can enter the vessel wall, leading to the accumulation of oxidized phospholipids in the arterial intima, which are crucial for initiating plaque inflammation and triggering vascular disease progression. In addition, Lp(a) may cause atherothrombosis through interactions between apoA (apolipoprotein A) and the platelet PAR-1 (protease-activated receptor 1) receptor, as well as competitive inhibition of plasminogen. Because Lp(a) is mostly determined on genetic bases, a 1-time assessment in a lifetime can suffice to identify patients with elevated levels. Mendelian randomization studies and post hoc analyses of randomized trials of LDL cholesterol–lowering drugs showed a causal link between Lp(a) concentrations and cardiovascular outcomes, with therapeutic reduction of Lp(a) expected to contribute to estimated cardiovascular risk mitigation. Many Lp(a)-lowering drugs, including monoclonal antibodies, small interfering ribonucleic acids, antisense oligonucleotides, small molecules, and gene editing compounds, are at different stages of clinical investigation and show promise for clinical use. In particular, increased Lp(a) testing and treatment are expected to have a substantial impact at the population level, enabling the identification of high-risk individuals and the subsequent prevention of a large number of cardiovascular events. Ongoing phase 3 trials will further elucidate the cardiovascular benefits of Lp(a) reduction over the long term, offering potential avenues for targeted interventions and improved cardiovascular outcomes.

Background: The optimal antithrombotic therapy for patients with atrial fibrillation undergoing percutaneous coronary intervention is a topic of debate. We aimed at defining the efficacy and safety of double antithrombotic therapy with single antiplatelet therapy (SAPT) plus a non–vitamin K antagonist oral anticoagulant (NOAC) against triple antithrombotic therapy with dual antiplatelet therapy (DAPT) added to a vitamin K antagonist (VKA), illustrating the pooled cumulative distribution of events, the ranking of different NOACs tested in NOAC+SAPT combination strategies, and the state of the current evidence in the field. Methods and Results: Randomized controlled trials meeting the inclusion criteria were identified. The primary efficacy end point was the composite of trial‐defined major adverse cardiac events. The primary safety end point was clinically significant bleeding. Secondary end points were the components of primary end points. Trial‐level pairwise and Bayesian network meta‐analyses, reconstructed Kaplan–Meier analyses, and trial sequential analysis were performed. Four randomized controlled trials (10 969 patients) were included. No differences were found in terms of major adverse cardiac events (hazard ratio [HR], 1.07; 95% CI, 0.94–1.22), and the NOAC+SAPT strategy showed a lower rate of clinically significant bleeding compared with VKA + DAPT (HR, 0.56; 95% CI, 0.39–0.80). These results were consistent in reconstructed Kaplan–Meier analyses. In the Bayesian network meta‐analysis, different NOACs displayed diverse risk–benefit profiles. Trial sequential analyses suggest that the evidence for the similarity in major adverse cardiac events compared with VKA + DAPT and the bleeding risk reduction observed with NOAC+SAPT is likely to be conclusive. Conclusions: NOAC+SAPT does not increase the risk of major adverse cardiac events and reduces the risk of bleeding compared with VKA + DAPT in AF patients undergoing percutaneous coronary intervention. Various NOACs may have different risk–benefit profiles in combination strategies. Registration: URL: https://www.crd.york.ac.uk/prospero/ ; Unique identifier: CRD42020151089.