Peri-procedural use of rivaroxaban in elective percutaneous coronary intervention to treat stable coronary artery disease. The X-PLORER trial.

Patients on rivaroxaban requiring percutaneous coronary intervention (PCI) represent a clinical conundrum. We aimed to investigate whether rivaroxaban, with or without an additional bolus of unfractionated heparin (UFH), effectively inhibits coagulation activation during PCI. Stable patients (n=108) undergoing elective PCI and on stable dual antiplatelet therapy were randomised (2:2:2:1) to a short treatment course of rivaroxaban 10 mg (n=30), rivaroxaban 20 mg (n=32), rivaroxaban 10 mg plus UFH (n=30) or standard peri-procedural UFH (n=16). Blood samples for markers of thrombin generation and coagulation activation were drawn prior to and at 0, 0.5, 2, 6-8 and 48 hours (h) after start of PCI. In patients treated with rivaroxaban (10 or 20 mg) and patients treated with rivaroxaban plus heparin, the levels of prothrombin fragment 1 + 2 at 2 h post-PCI were 0.16 [0.1] nmol/l (median) [interquartile range, IQR] and 0.17 [0.2] nmol/l, respectively. Thrombin-antithrombin complex values at 2 h post-PCI were 3.90 [6.8]µg/l and 3.90 [10.1] µg/l, respectively, remaining below the upper reference limit (URL) after PCI and stenting. This was comparable to the control group of UFH treatment alone. However, median values for thrombin-antithrombin complex passed above the URL with increasing tendency, starting at 2 h post-PCI in the UFH-alone arm but not in rivaroxaban-treated patients. In this exploratory trial, rivaroxaban effectively suppressed coagulation activation after elective PCI and stenting.

High-dose tirofiban pretreatment reduces the need for bail-out study medication in patients with ST-segment elevation myocardial infarction: results of a subgroup analysis of the On-TIME 2 trial.

OBJECTIVE: This study investigated the outcome of patients who received bail-out study medication and evaluated whether high-dose tirofiban (HDT) pretreatment may reduce the need for bail-out study medication. DESIGN: A prespecified analysis of the multicentre, double-blind, placebo controlled, randomised On-TIME 2 trial. Bail-out use of study medication was predefined and part of the combined clinical end point. PATIENTS: 984 patients excluded from many coronary intervention hospitals in different countries were randomly assigned to HDT or placebo. In the subgroup who received blinded bail-out treatment, patients pretreated with placebo who received bail-out HDT were compared with those pretreated with HDT who received bail-out placebo. Interventions Routine prehospital initiation of HDT versus bail-out use of HDT. MAIN OUTCOME MEASURES: Electrocardiographic and clinical outcome. RESULTS: Blinded bail-out study medication was used in 24% (237/980) of patients, with a higher rate in patients pretreated with placebo: 29% (140/492) versus 20% (97/488), p=0.002. Bail-out versus no bail-out use of study medication was associated with more residual ST deviation (5.5±7.2 vs 3.7±4.8 mm, p=0.005), and worse clinical outcome (major adverse cardiac events (MACE) at 30 days 12.2% vs 5.6%, p<0.001), mainly due to poor outcome in patients who received HDT bail-out. In patients pretreated with HDT who received placebo bail-out study medication, residual ST deviation and clinical outcome did not differ significantly compared with patients who did not receive bail-out medication (4.0±4.6 vs 3.7± 4.8 mm, p=0.703, MACE 7.2% vs 5.6%, p=0.535). CONCLUSIONS: Routine prehospital treatment with HDT significantly reduced the use of blinded bail-out study medication. The need for bail-out therapy was associated with a less favourable outcome. This analysis suggests that routine pretreatment is superior to provisional use of HDT in patients with ST-segment elevation myocardial infarction.

Marked reduction of early stent thrombosis with pre-hospital initiation of high-dose Tirofiban in ST-segment elevation myocardial infarction.

BACKGROUND: No randomized comparisons are yet available evaluating the effect of pre-hospital high dose tirofiban on the incidence of early stent thrombosis after primary percutaneous coronary intervention (PCI). OBJECTIVES: The aim of this analysis was to evaluate whether routine pre-hospital administration of high-dose tirofiban in ST-segment elevation myocardial infarction (STEMI) decreases the incidence of early stent thrombosis after primary PCI. PATIENTS/METHODS: The Ongoing Tirofiban in Myocardial Evaluation (On-TIME) 2 trial was a prospective multicenter study of consecutive STEMI patients referred for primary PCI in which patients were randomized to pre-hospital no high-dose tirofiban/placebo. We examined the incidence of Academic Research Consortium definite and probable early stent thrombosis and determined predictors and outcome of early stent thrombosis. RESULTS: Primary PCI was performed in 1203 out of 1398 patients (86.1%). In 1073 patients (89.2%) a coronary stent was placed. Early stent thrombosis occurred in 39 patients (3.6%). Pre-hospital initiation of high-dose tirofiban significantly reduced early stent thrombosis (2.1% vs. 5.2%, P = 0.006) and was associated with a lower incidence of urgent repeat PCI (1.9% vs. 5.2%, P = 0.005). Early stent thrombosis, as well as pre-hospital initiation of high-dose tirofiban, was independently associated with 30-day mortality. CONCLUSIONS: Pre-hospital initiation of high-dose tirofiban reduces the 30-day incidence of stent thrombosis in STEMI patients treated with primary PCI and stenting. Early stent thrombosis and pre-hospital initiation of high-dose tirofiban were independent predictors of 30-day mortality.

Efficacy of SDZ RAD compared with CsA monotherapyand combined Rad/FTY720 treatment in a murine cardiac allotransplantation model.

OBJECTIVE: The macrolide immunosuppressant RAD and the immunomodulator FTY720 have distinct mechanisms ofaction. We investigated the efficacy of RAD (everolimus, certican) alone or in combination with FTY720 on graft survival (GS)and histology in comparison with CsA, using mouse strains with strong MHC disparity. METHODS: Heterotopic cardiac grafting was performed using the C57B1/6 to C3H strain combination. Osmotic mini-pumps filled with CsA or RAD were implanted subcutaneously. IFTY720 was administered as a single daily dose by gavage. Peripheral lymphocyte count (PLC) was determined at 1, 4 and 8 weeks or on the day of sacrifice. Body weight was recorded on the day of surgery and weekly. Grafts were histologically evaluated. MAIN FINDINGS: In placebo-treated mice the allografts were rejected after 7 days. Monotherapy with 10 and 30 mg/kg/day CsA achieved 10 and 22.5 days median survival time (MST), while 0.1, 0.3, 1 and 3 mg/kg/day RAD resulted in 10.5, 20, > 56 and > 56 days MST, respectively. FTY720 lowered the PLC significantly, while the lower CsA dose and RAD did not influence the PLC. Adding FTY720 to the 0.6 mg/kg/day dose of RAD extended GS modestly but reduced significantly the perivascular infiltration and endothelialitis in the grafts compared with RAD monotherapy. CONCLUSIONS: Underthe conditions of the present experiment RAD was more potent than CsA in extending the GS. Combining FTY720 and RADwas well tolerated with respect to weight gain and lack of clinically detectable infections in the mice. The 2-drug regimens suppressed the inflammatory allo-response better than RAD monotherapy.

Combined FTY720/cyclosporine A treatment promotes graft survival and lowers the peripheral lymphocyte count in DA to lewis heart and skin transplantation models.

OBJECTIVE: The immunomodulator, FTY720, lowers the peripheral lymphocyte count (PLC) by inducing migration of circulating lymphocytes to secondary lymphoid organs. We investigated the efficacy of mono- vs. combined-FTY720/CsA therapy on graft survival (GS) and on lowering the PLC in a solid organ and a skin graft model, using strains with strong MHC disparity. METHODS: Heterotopic cardiac or tail skin grafting was performed using the DA (RT1a) to Lewis (RT1(1)) rat strain combination. FTY720 was administered as a single daily dose by gavage alone or in combination with subcutaneously delivered CsA. PLC, body weight and drug concentrations were determined on day 7, 28, or the day of rejection. MAIN FINDINGS: In placebo-treated animals the heart and skin allografts rejected after 6 and 8 days. FTY720 delayed rejection of both the solid organ and skin grafts. The maximal effect was achieved at 1 mg x kg(-l) x day(-1) FTY720, resulting in a median survival time (MST) of 14 days for both allotransplants comparable to the effect achieved by 1 mg x kg x day(-1) CsA in both models. In the cardiac graft experiment with CsA co-administration, doses of 0.3 and 1 mg/kg were used. Under these conditions very small doses of FTY720 were effective in maintaining grafts throughout the treatment period. Adding higher FTY720 doses to the 1 mg x kg(-1) x day(-1) CsA was needed to effectively extend the skin GS, e.g. 0.3 mg x kg(-l) x day(-1) FTY720 prolonged GS from 13 to 47.5 days MST, i.e. well beyond the 28 day-treatment period. CsA did not influence the PLC at clinically relevant doses. FTY720 lowered the PLC significantly and dose-dependently, at doses lower than those needed for the prolongation of both cardiac and skin GS with FTY720 monotherapy. In rats with skin grafts the PLC was markedly lowered up to 1 mg x kg(-1) x day(-1) FTY720, whereas, in the heart model, it was lowered up to 0.1 mg x kg(-1) x day(-1). Independently of the graft type, within the combination regimens 0.3 mg x kg(-1) x day(-1) FTY720 achieved a maximal PLC depletion. CONCLUSIONS: Combining FTY720 and CsA was very well tolerated with respect to weight gain and lack of any clinically detectable infections. In the strain combination used FTY720 monotherapy was less effective than previously reported in maintaining grafts. The two-drug regimens extended strikingly the GS for both models. However, the prolongation of the heart GS was smoothly dose-related with FTY720 doses ranging from 0.01 to 1 mg x kg(-1) x day(-1) , whereas, the skin graft prolongation was modest at doses up to 0.1 mg x kg(-1) x day(-1) and remarkably enhanced at 0.3 and 1 mg x kg(-1) x day(-1) FTY720.

Comparative hemodynamic studies of isradipine and dihydralazine in atherosclerotic and normal rabbits.

The hemodynamic effects of the calcium antagonist isradipine (code name PN 200-110) and the arteriolar vasodilator dihydralazine were compared in atherosclerotic (cholesterol-fed) and normal conscious rabbits with implanted catheters. Regional blood flows were measured using the microsphere technique. Cardiac output and blood flow to several organs, especially to the gastrointestinal system, but not to the heart and brain, were lower in atherosclerotic rabbits than in normal ones. Intravenous isradipine (10 and 30 micrograms/kg) increased heart rate less in atherosclerotic than in normal rabbits. Isradipine had no effect on the surface electrocardiogram (ECG). In contrast, 0.4 mg/kg dihydralazine caused depression of the ST segment while decreasing blood pressure similarly. This was explained partly by an intramyocardial maldistribution of coronary blood flow (using microspheres). Isradipine increased and dihydralazine decreased flow to the brain. Isradipine redistributed cardiac output in atherosclerotic and normal animals in favor of the heart, brain, and skeletal muscle. However, in atherosclerotic animals, the high dose was less effective than the low dose in some vascular beds. Thus, isradipine is not a general vasodilator in either atherosclerotic or in normal animals, but favors the vital organs. This redistribution of cardiac output contrasts favorably with that induced by dihydralazine.

Acceleration of blood in the aorta: a parameter useful for evaluating cardiotonic and afterload reducing substances.

Peak acceleration of blood in the aorta was measured in chloralose-urethane anesthetized open-chest cats with an electromagnetic flow probe around the aortic root. The effects of substances used in the treatment of chronic congestive heart failure were evaluated in this model. Isoprenaline, noradrenaline, and ouabain increased peak acceleration dose-dependently, while blood pressure, cardiac output, and heart rate were influenced differently by each drug. Nitroglycerin and nitroprusside sodium, afterload reducing agents used for the treatment of congestive heart failure, also increased peak acceleration; an effect that in the case of nitroprusside sodium was shown to be mediated by beta-receptors and probably attributable to baroreceptor activation. This simple model was judged to be suitable for evaluating positive inotropic and afterload reducing substances as long as its low sensitivity to heart rate increasing interventions is correctly appreciated.