Background: To quantify the association between effects of interventions on carotid intima-media thickness (cIMT) progression and their effects on cardiovascular disease (CVD) risk. Methods: We systematically collated data from randomized, controlled trials. cIMT was assessed as the mean value at the common-carotid-artery; if unavailable, the maximum value at the common-carotid-artery or other cIMT measures were used. The primary outcome was a combined CVD end point defined as myocardial infarction, stroke, revascularization procedures, or fatal CVD. We estimated intervention effects on cIMT progression and incident CVD for each trial, before relating the 2 using a Bayesian meta-regression approach. Results: We analyzed data of 119 randomized, controlled trials involving 100 667 patients (mean age 62 years, 42% female). Over an average follow-up of 3.7 years, 12 038 patients developed the combined CVD end point. Across all interventions, each 10 μm/y reduction of cIMT progression resulted in a relative risk for CVD of 0.91 (95% Credible Interval, 0.87–0.94), with an additional relative risk for CVD of 0.92 (0.87–0.97) being achieved independent of cIMT progression. Taken together, we estimated that interventions reducing cIMT progression by 10, 20, 30, or 40 μm/y would yield relative risks of 0.84 (0.75–0.93), 0.76 (0.67–0.85), 0.69 (0.59–0.79), or 0.63 (0.52–0.74), respectively. Results were similar when grouping trials by type of intervention, time of conduct, time to ultrasound follow-up, availability of individual-participant data, primary versus secondary prevention trials, type of cIMT measurement, and proportion of female patients. Conclusions: The extent of intervention effects on cIMT progression predicted the degree of CVD risk reduction. This provides a missing link supporting the usefulness of cIMT progression as a surrogate marker for CVD risk in clinical trials.

Gain-of-function (GOF) variants in GP1BA cause platelet-type von Willebrand disease (PT-VWD), a rare inherited autosomal dominant bleeding disorder characterized by enhanced platelet GPIbα to von Willebrand factor (VWF) interaction, and thrombocytopenia. To date, only 6 variants causing PT-VWD have been described, 5 in the C-terminal disulfide loop of the VWF-binding domain of GPIbα and 1 in the macroglycopeptide. GOF GP1BA variants generate a high-affinity conformation of the C-terminal disulfide loop with a consequent allosteric conformational change on another region of GPIbα, the leucine-rich-repeat (LRR) domain. We identified a novel GP1BA variant (p.Arg127Gln) affecting the LRR5 domain of GPIbα in a boy with easy bruising and laboratory test results suggestive of PT-VWD. We thus aimed to investigate the impact of the p.Arg127Gln variant on GPIbα affinity for VWF and GPIbα structure. Chinese hamster ovary cells expressing p.Arg127Gln GPIbα showed increased binding of VWF induced by ristocetin and enhanced tethering on immobilized VWF as compared with cells expressing wild-type GPIbα. Surface plasmon resonance confirmed that p.Arg127Gln enhances the binding affinity of GPIbα for VWF. Hydrogen-deuterium exchange mass spectrometry showed that p.Arg127Gln of LRR, while having little effect on the dynamics of the LRR locally, enhances the conformational dynamics of the GPIbα C-terminal disulfide loop structure. Our data demonstrate for the first time that GOF variants outside the GPIbα C-terminal disulfide loop may be pathogenic and that aminoacidic changes in the LRR may cause allosterically conformational changes in the C-terminal disulfide loop of GPIbα, inducing a conformation with high affinity for VWF.

GPIV (CD36) is a multifunctional membrane protein expressed on various cells, including platelets, where it plays a role in adhesion and activation through the interaction with its ligands, including collagen types I and III and thrombospondin 1. Inherited GPIV deficiency, historically recognized in anti-Naka alloimmunized East Asian donors, is considered asymptomatic and associated with normal platelet aggregation, although impaired adhesion under high-flow conditions has been reported. Here, we reconsider the molecular basis, epidemiology and functional consequences of GPIV deficiency and report four unrelated patients in whom heterozygous CD36 variants are associated with markedly reduced platelet GPIV expression and a clinically relevant mucocutaneous bleeding diathesis. Patients suffered lifelong bleeding symptoms despite normal light-transmission aggregometry and platelet granule content and release and displayed decreased GPIV expression. Three of them showed slightly decreased VWF. Platelet adhesion to Type I collagen was reduced at high shear. These cases suggest for the first time an association between CD36 gene variants and bleeding and underscore the importance of including GPIV in the diagnostic workup of inherited platelet disorders, particularly when conventional assays do not reveal abnormalities.