Factors Influencing 1st and 2nd Generation Drug-Eluting Stent Performance: Understanding the Basic Pharmaceutical Drug-in-Polymer Formulation Factors Contributing to Stent Thrombosis Do We Really Need to Eliminate the Polymer?

Drug-eluting stents (DES) have a major role in treating cardiovascular disease. The evolution of bare metal stents into 1st generation durable-polymer DES (DP-DES) reduced the rate of in-stent restenosis (ISR) and the need for repeat-revascularization. However, clinical outcomes showed similar rates of late stent thrombosis (ST<1 year) and higher rates of very late stent thrombosis (ST>1 year) necessitating the advent of 2nd generation more biocompatible polymer DES and biodegradable-polymer DES (BP-DES) that reduced ST rates with shorter dual anti-platelet therapy (DAPT). Despite the improvements in drugs and polymer biocompatibility for both durable and biodegradable polymers, stent thrombosis remains an issue. Doubts remain about the safety and efficacy of the more biocompatible 2nd generation durable polymers in respect to vessel inflammatory and thrombogenic response as compared to biodegradable polymers despite clinical trial and meta-analyses evidence indicating that 2nd generation DP-DES are non-inferior to BP-DES for stent thrombosis. A long-term presence of the polymer can cause inflammation and thrombogenesis. However, the cause of stent thrombosis is multi-factorial from a drug-in-polymer formulation perspective; e.g., drug release kinetics, drug physiochemical and pharmacological properties, degradation kinetics; polymer biocompatibility and hemocompatibility and coating properties. It appears that the focus should be on controlling burst release and developing more biocompatible, durable polymers, especially considering the cost of PCI utilizing biodegradable, polymer-free and bioresorbable scaffolds. This may give an insight into certain DP-DES effectiveness as compared to BP-DES for the existing clinical data and improve future stent development.

Incidence and predictors of target lesion failure in patients undergoing contemporary DES implantation-Individual patient data pooled analysis from 6 randomized controlled trials.

BACKGROUND: Drug-eluting stents (DESs) have improved clinical outcomes of patients undergoing percutaneous coronary intervention (PCI). Nevertheless, adverse events related to previously treated lesion still occur. We sought to evaluate the incidence and predictors of target lesion failure (TLF) in patients undergoing contemporary DES implantation. METHODS: Patient-level data from 6 prospective, randomized trials were pooled, and DES treatment outcomes were analyzed at up to 5 years. Primary outcome was TLF (cardiac death, target lesion revascularization, or target vessel myocardial infarction). Cox proportional-hazards model was used to identify predictors of TLF. RESULTS: Overall, 10,072 patients were included in the analysis. TLF rate was 1.7%, 4.3%, and 11.9% at 30 days, 1 year, and 5 years, respectively. The only independent predictor of TLF at 30 days was stent length (hazard ratio [HR] 1.017, 95% CI 1.011-1.024, P < .0001). Moderate/severe calcification, stent length and post procedural diameter sthenosis were predictors between 30 days to 1 year but not at 1 to 5 years. Reference vessel diameter was the only lesion-related predictor at 5 years (P = .003). Clinical predictors of TLF between 30 days and 1 year were diabetes and hypertension (P < .01 for both), and between 1 and 5 years, diabetes (HR 1.40, 95% CI 1.13-1.73, P = .002), prior coronary artery bypass grafting (HR 2.52, 95% CI 1.92-3.30, P < .0001), and prior PCI (HR 1.29, 95% CI 1.02-1.64, P = .04) predicted TLF. CONCLUSIONS: Predictors of TLF vary in the early, late, and very late postprocedural periods. Reference vessel diameter was the only lesion-related predictor of long-term TLF; clinical predictors were diabetes, prior coronary artery bypass grafting, and prior PCI.

Outcomes of the Tryton-dedicated bifurcation stent for the treatment of true coronary bifurcations: Individual-patient-data pooled analysis.

OBJECTIVES: We aimed to evaluate the safety and efficacy of the dedicated Tryton side branch (SB) stent for the treatment of true bifurcations involving large SBs. BACKGROUND: Bifurcation lesions are associated with lower procedural success and a higher risk of adverse cardiac events. Provisional stenting (PS) is currently the default approach for the treatment of bifurcation lesions. The Tryton stent is a dedicated bifurcation stent system for the treatment of true bifurcation lesions. METHODS: We performed an individual-patient-data pooled post-hoc analysis of the Tryton Pivotal randomized controlled trial and post-approval Confirmatory Study. Only patients with true bifurcations involving a SB ≥ 2.25 mm in diameter were included. The primary endpoint was non-inferiority of Tryton compared with PS for target vessel failure (TVF) at 1 year. RESULTS: Of the 411 patients meeting the criteria for enrolment, 287 patients were treated with the Tryton stent and 124 with PS. Procedural success was higher in the Tryton group (95.4 versus 82.3%, P < 0.0001). TVF at 1 year was 8.1% in the Tryton group and 9.7% in the PS group, meeting the pre-specified criteria for non-inferiority established for the randomized controlled trail (pnon-inferiority = 0.02). At 9-month angiographic follow-up, SB diameter stenosis was significantly lower in the Tryton group (29.3 ± 21.9 versus 41.1 ± 17.5, P = 0.0008) and in-segment binary restenosis (diameter stenosis ≥ 50%) was higher in the PS group (19.0 versus 34.2%, respectively, P = 0.052). CONCLUSIONS: In patients with true bifurcations involving a large SB, treatment with the Tryton SD Stent was clinically non-inferior to PS and showed favorable angiographic outcomes.

IRAK-4- and MyD88-dependent pathways are essential for the removal of developing autoreactive B cells in humans.

Most autoreactive B cells are normally counterselected during early B cell development. To determine whether Toll-like receptors (TLRs) regulate the removal of autoreactive B lymphocytes, we tested the reactivity of recombinant antibodies from single B cells isolated from patients deficient for interleukin-1 receptor-associated kinase 4 (IRAK-4), myeloid differentiation factor 88 (MyD88), and UNC-93B. Indeed, all TLRs except TLR3 require IRAK-4 and MyD88 to signal, and UNC-93B-deficient cells are unresponsive to TLR3, TLR7, TLR8, and TLR9. All patients suffered from defective central and peripheral B cell tolerance checkpoints, resulting in the accumulation of large numbers of autoreactive mature naive B cells in their blood. Hence, TLR7, TLR8, and TLR9 may prevent the recruitment of developing autoreactive B cells in healthy donors. Paradoxically, IRAK-4-, MyD88-, and UNC-93B-deficient patients did not display autoreactive antibodies in their serum or develop autoimmune diseases, suggesting that IRAK-4, MyD88, and UNC-93B pathway blockade may thwart autoimmunity in humans.

Non-linear plasma protein binding of cannabidiol.

BACKGROUND: Cannabidiol is highly bound to plasma proteins. Changes in its protein binding can lead to altered unbound plasma concentrations and result in alteration of pharmacological activity of cannabidiol-containing medications. This research has assessed non-linearity of cannabidiol plasma protein binding and the potential effect of tizoxanide on the binding. METHOD: Cannabidiol protein binding was evaluated by ultrafiltration technique. Human plasma was spiked with cannabidiol stock solution to produce samples of various concentrations. For interaction study potential interactant tizoxanide was added in each sample. All samples were processed through Amicon Micropartition system and analyzed by HPLC. RESULTS: The study has detected cannabidiol binding to borosilicate glass (9%) and polyethylene plastics (15%). In the interaction study the mean protein unbound fraction of cannabidiol was 0.05 (5%), indicating no binding interaction between cannabidiol and tizoxanide since cannabidiol unbound fraction without tizoxanide was also 5%. The cannabidiol fraction unbound was more than 2-fold greater at high concentrations compared to low concentrations. CONCLUSION: a). At high concentrations cannabidiol plasma protein binding is non-linear. The non-linearity can affect elimination and medicinal effect of cannabidiol drugs. b). Borosilicate and polyethylene containers should be avoided in formulation, packing and administration of cannabidiol-containing medicines to guarantee correct doses. c). Cannabidiol medications can be co-administered with tizoxanide without caution.

On-Treatment Platelet Reactivity and Ischemic Outcomes in Patients With Diabetes Mellitus: Two-Year Results From ADAPT-DES.

Background Diabetes mellitus and high platelet reactivity (HPR) on clopidogrel are both associated with increased risk of ischemic events after percutaneous coronary intervention, but whether the HPR-associated risk of adverse ischemic events differs by diabetes mellitus status is unknown. Methods and Results ADAPT-DES (Assessment of Dual Antiplatelet Therapy With Drug-Eluting Stents) was a prospective, multicenter registry of patients treated with coronary drug-eluting stents. HPR was defined as P2Y12 reaction units >208 by the VerifyNow point-of-care assay. Cox multivariable analysis was used to assess whether HPR-associated risk of major adverse cardiac events (MACE; cardiac death, myocardial infarction, or stent thrombosis) varied for patients with insulin-treated diabetes mellitus (ITDM), non-ITDM, and no diabetes mellitus. Diabetes mellitus and HPR were included in an interaction analysis. Of 8582 patients enrolled, 2429 (28.3%) had diabetes mellitus, of whom 998 (41.1%) had ITDM. Mean P2Y12 reaction units were higher in patients with diabetes mellitus versus without diabetes mellitus, and HPR was more frequent in patients with diabetes mellitus. HPR was associated with consistently increased 2-year rates of MACE in patients with and without diabetes mellitus (Pinteraction=0.36). A significant interaction was present between HPR and non-insulin-treated diabetes mellitus versus ITDM for 2-year MACE (adjusted hazard ratio [HR] for non-ITDM, 2.28 [95% CI, 1.39-3.73] versus adjusted HR for ITDM, 1.02 [95% CI, 0.70-1.50]; Pinteraction=0.01). Conclusions HPR was more common in patients with diabetes mellitus and was associated with an increased risk of MACE in both patients with and without diabetes mellitus. In patients with diabetes mellitus, a more pronounced effect of HPR on MACE was present in lower-risk non-ITDM patients than in higher-risk patients with ITDM. Registration URL: https://clinicaltrials.gov/ct2/show/NCT00638794; Unique identifier: NCT00638794. ADAPT-DES (Assessment of Dual Antiplatelet Therapy With Drug-Eluting Stents).

Complement receptor 2/CD21- human naive B cells contain mostly autoreactive unresponsive clones.

Complement receptor 2-negative (CR2/CD21(-)) B cells have been found enriched in patients with autoimmune diseases and in common variable immunodeficiency (CVID) patients who are prone to autoimmunity. However, the physiology of CD21(-/lo) B cells remains poorly characterized. We found that some rheumatoid arthritis (RA) patients also display an increased frequency of CD21(-/lo) B cells in their blood. A majority of CD21(-/lo) B cells from RA and CVID patients expressed germline autoreactive antibodies, which recognized nuclear and cytoplasmic structures. In addition, these B cells were unable to induce calcium flux, become activated, or proliferate in response to B-cell receptor and/or CD40 triggering, suggesting that these autoreactive B cells may be anergic. Moreover, gene array analyses of CD21(-/lo) B cells revealed molecules specifically expressed in these B cells and that are likely to induce their unresponsive stage. Thus, CD21(-/lo) B cells contain mostly autoreactive unresponsive clones, which express a specific set of molecules that may represent new biomarkers to identify anergic B cells in humans.

Impact of renin-angiotensin system inhibitors after revascularization of patients with left main coronary artery disease.

BACKGROUND: There is a paucity of data regarding the effect of inhibition of the renin-angiotensin system on outcomes after percutaneous coronary intervention (PCI) and coronary artery bypass grafting (CABG). We sought to examine long-term outcomes of patients with left main coronary disease (LMCAD) randomized to PCI with fluoropolymer-based cobalt-chromium everolimus-eluting stents or CABG according to treatment at discharge with angiotensin-converting enzyme inhibitors (ACEI) or angiotensin receptor blockers (ARB) in the large-scale, multicenter, randomized EXCEL trial. METHODS: EXCEL randomized 1905 patients with LMCAD of low and intermediate anatomical complexity (visually-assessed SYNTAX score ≤32) to PCI (n = 948) versus CABG (n = 957). Patients were categorized according to whether they were treated with ACEI/ARB at discharge; their outcomes from discharge to 5 years were examined using multivariable logistic regression with an offset for follow-up time. RESULTS: Among 1775 patients discharged alive with known ACEI/ARB treatment status, 896 (50.5%) were treated with one of these agents. Among those treated with ACEI/ARB, the 5-year rate of all-cause death was similar after PCI or CABG (10.7% versus 9.8% respectively, adjOR, 0.94; 95% CI, 0.56-1.57) in contrast to patients not treated with ACEI/ARB (15.0% versus 7.8%, respectively, adjOR, 2.20; 95% CI, 1.32-3.67) (Pinteraction = 0.02). Significant interactions between treatment arm (PCI versus CABG) and ACEI/ARB treatment status were also found for cardiovascular death (Pinteraction = 0.03), ischemia-driven revascularization (Pinteraction = 0.03), target vessel revascularization (Pinteraction = 0.007) and target vessel failure (Pinteraction = 0.0009). CONCLUSION: In the EXCEL trial, the postdischarge rates of death and revascularization after 5 years were similar after PCI and CABG in patients with LMCAD treated with ACEI/ARB at discharge. In contrast, event rates were higher after PCI versus CABG in those not so treated.