804-4 A Randomized, Double-blind Trial of Streptokinase Versus Placebo for the Management of Unstable Angina and Non-Q-wave Myocardial Infarction in Patients with Previous Coronary Artery Bypass Surgery

This trial investigated the potential usefulness of thrombolysis in patients with previous coronary artery bypass surgery admired for unstable angina and non-Q-wave myocardial infarction, the rationale being more frequent non-Q-wave infarction in these patients and a high-fibrin content of older grafts. A total of 125 consecutive patients with symptoms evolving for less than 24 hr were randomized to intravenous streptokinase 1.5 million Units in 45 min, or to placebo. All patients received concomitant intravenous heparin, oral aspirin and standard anti-ischemic therapy. Mean age (62±9 yrs). sex (78% male). time of previous surgery (8±0.5 yrs), presence of a previous myocardial infarction (63%). prior medication including aspirin in 66%, an abnormal ECG at admission (79%) and time to treatment after the last ischemic episode (10±9 hr) were similar in the 2 study groups.Fatal and non-fatal myocardial infarctions in hospital occurred in 7 streptokinase (11.1%) and 3 placebo (4.8%) patients (relative risk 2.3, 95% confidence limits 0.62–8.48, p=0.19) and at 1 month in an additional 2 patients in each group. Refractory angina in hospital was observed in 12 (19.1%) streptokinase patients and 13 (20.9%) placebo patients. A revascularization procedure because of recurrent symptoms was required at 1 month in respectively 22 (34.9%) and 16 (25.8%) patients.ConclusionThe early cardiac event rate in unstable angina associated with previous bypass surgery is high. The nonsignificant excess in the risk of myocardial infarction with streptokinase in this population most likely to benefit, is similar to the excess reported in other populations of patients with unstable angina and non-a-wave myocardial infarction and supports the lack of benefit of thrombolysis in unstable angina

Platelet Glycoprotein IIb/IIIa Receptor Inhibition in Non-ST-Elevation Acute Coronary Syndromes

BACKGROUND: Glycoprotein (GP) IIb/IIIa receptor blockers prevent life-threatening cardiac complications in patients with acute coronary syndromes without ST-segment elevation and protect against thrombotic complications associated with percutaneous coronary interventions (PCIs). The question arises as to whether these 2 beneficial effects are independent and additive. METHODS AND RESULTS: We analyzed data from the CAPTURE, PURSUIT, and PRISM-PLUS randomized trials, which studied the effects of the GP IIb/IIIa inhibitors abciximab, eptifibatide, and tirofiban, respectively, in acute coronary syndrome patients without persistent ST-segment elevation, with a period of study drug infusion before a possible PCI. During the period of pharmacological treatment, each trial demonstrated a significant reduction in the rate of death or nonfatal myocardial infarction in patients randomized to the GP IIb/IIIa inhibitor compared with placebo. The 3 trials combined showed a 2.5% event rate in this period in the GP IIb/IIIa inhibitor group (N=6125) versus 3.8% in placebo (N=6171), which implies a 34% relative reduction (P<0.001). During study medication, a PCI was performed in 1358 patients assigned GP IIb/IIIa inhibition and 1396 placebo patients. The event rate during the first 48 hours after PCI was also significantly lower in the GP IIb/IIIa inhibitor group (4. 9% versus 8.0%; 41% reduction; P<0.001). No further benefit or rebound effect was observed beyond 48 hours after the PCI. CONCLUSIONS: There is conclusive evidence of an early benefit of GP IIb/IIIa inhibitors during medical treatment in patients with acute coronary syndromes without persistent ST-segment elevation. In addition, in patients subsequently undergoing PCI, GP IIb/IIIa inhibition protects against myocardial damage associated with the intervention

Requirements for Membrane Attack Complex Formation and Anaphylatoxins Binding to Collagen-Activated Platelets

The activation of complement during platelet activation is incompletely understood.We sought to explore the formation of C5b-9 and anaphylatoxins binding to collagen-activated platelets.C5b-9, anaphylatoxins C3a, C4a and C5a, and anaphylatoxin receptors C3aR1 and C5aR were measured by flow cytometry and/or confocal microscopy. Platelet microparticles were quantified by flow cytometry, and their C5b-9 content was determined by western blot analyses. In all experiments, sodium citrate was used for blood anticoagulation.C5b-9 rapidly formed on the platelet surface following activation with collagen, TRAP, ADP or A23187, but was surprisingly restricted to a subset of platelets (1 to 15%) independently of P-selectin or phosphatidylserine exposure. Following collagen activation, C5b-9-positive platelets in thrombi were found associated with collagen fibres. C5b-9 formation was obliterated by Mg(2+)-EGTA and significantly reduced by the thrombin inhibitor hirudin (-37%, p<0.05), but was unaffected by chondroitinase, compstatin, SCH79797 (PAR-1 inhibitor), or in the PRP of a MBL-deficient donor. Compstatin and Mg(2+)-EGTA, but not hirudin, SCH79797 or chondroitinase, inhibited the formation of collagen-induced microparticles (-71% and -44%, respectively, p<0.04). These microparticles contained greater amounts of C5b-9 compared with the other agonists. Platelet activation by collagen or convulxin resulted in the strong binding of anaphylatoxins and the exposure of receptors C3aR1 and C5aR (CD88) on their surface.C5b-9 formation on collagen-activated platelets is i) partially controlled by thrombin, ii) restricted to a subset of platelets, and iii) can occur without P-selectin expression or phosphatidylserine exposure. Activated platelets bind anaphylatoxins on their surface and express C3a and C5a receptors, which may contribute to the localization of inflammatory processes during thrombosis

A united statement of the global chiropractic research community against the pseudoscientific claim that chiropractic care boosts immunity.

BACKGROUND: In the midst of the coronavirus pandemic, the International Chiropractors Association (ICA) posted reports claiming that chiropractic care can impact the immune system. These claims clash with recommendations from the World Health Organization and World Federation of Chiropractic. We discuss the scientific validity of the claims made in these ICA reports. MAIN BODY: We reviewed the two reports posted by the ICA on their website on March 20 and March 28, 2020. We explored the method used to develop the claim that chiropractic adjustments impact the immune system and discuss the scientific merit of that claim. We provide a response to the ICA reports and explain why this claim lacks scientific credibility and is dangerous to the public. More than 150 researchers from 11 countries reviewed and endorsed our response. CONCLUSION: In their reports, the ICA provided no valid clinical scientific evidence that chiropractic care can impact the immune system. We call on regulatory authorities and professional leaders to take robust political and regulatory action against those claiming that chiropractic adjustments have a clinical impact on the immune system