Topical Synthetic Platelets Loaded With Gentamicin Decrease Bacteria in Deep Partial-Thickness Burns.

INTRODUCTION: Prolonged inflammation and infection in burns may cause inadequate healing. Platelet granules contain anti-inflammatory mediators that impact wound healing. Synthetic platelets (SPs) avoid portability and storage difficulties of natural platelets and can be loaded with bioactive agents. We evaluated wound healing outcomes in deep partial-thickness (DPT) burns treated topically with SP loaded with antibiotics. MATERIALS AND METHODS: Thirty DPT burns were created on the dorsum of two Red Duroc hybrid pigs. Six wounds were randomized into five groups: SP alone, SP loaded with gentamicin vesicles, SP with gentamicin mixture, vehicle control (saline), or dry gauze. Wounds were assessed from postburn days 3-90. Primary outcome was re-epithelialization percentage at postburn day 28. Secondary outcomes included wound contraction percentage, superficial blood flow relative to normal skin controls, and bacterial load score. RESULTS: Results showed that re-epithelialization with the standard of care (SOC) was 98%, SP alone measured 100%, SP loaded with gentamicin vesicles was 100%, and SP with gentamicin mixture was 100%. Wound contraction was 5.7% in the SOC and was ∼10% in both the SP loaded with gentamicin vesicles and SP with gentamicin mixture groups. Superficial blood flow in the SOC was 102.5%, SP alone was 170%, the SP loaded was 155%, and gentamicin mixture 162.5%. Bacterial load score in the SOC was 2.2/5.0 and was significantly less at 0.8/5.0 in SP loaded with gentamicin vesicles (P > 0.05). SP and gentamicin mixture scored 2.7 and 2.3/5.0. CONCLUSIONS: Topical SP treatment did not significantly improve outcomes. However, SP loaded with gentamicin-infused vesicles decreased bacterial load.

Characteristics and outcomes of adults with cytomegalovirus-associated thrombocytopenia: a case series and literature review.

Cytomegalovirus (CMV) is a ubiquitous virus that infects people worldwide. CMV is known to trigger thrombocytopenia, but this association is probably underdiagnosed since CMV infection in healthy adults is usually either asymptomatic or causes only mild symptoms. A systematic literature review was carried out and yielded 23 publications that reported 25 patients. All haematology centres in Israel were searched for adult immunocompetent patients with CMV-associated thrombocytopenia, and five new cases were identified. The median age of the combined 30 patients was 33 years (range 18-80), 73% were men, 77% presented with CMV-related symptoms, 48% had enlarged spleens, 95% had atypical lymphocytes in peripheral blood and 68% had elevated transaminase levels. The response rate to first-line steroid-containing regimens was only 31%, whereas 11 patients who were treated with an anti-CMV agent had a response rate of 82%. Moreover, four patients received thrombopoietin receptor agonists (TPO-RA) to which three (75%) responded. Taken together, these distinctive features of a case with thrombocytopenia should alert to CMV infection as the source. While steroids were effective in less than one-third of the cases, both anti-CMV therapy and TPO-RA exhibited excellent efficacy, suggesting that those agents should be introduced earlier in the therapeutic course.

Prothrombin Complex Concentrate before Urgent Surgery in Patients Treated with Rivaroxaban and Apixaban.

INTRODUCTION: Patients treated with direct Xa inhibitors may require urgent surgery. Administration of prothrombin complex concentrate (PCC) in this setting is common; however, it is based on limited experience in healthy volunteers. OBJECTIVE: To characterize the population receiving PCC for apixaban/rivaroxaban reversal prior to an urgent surgery and evaluate its efficacy and safety. METHODS: This was a retrospective study in 2 tertiary hospitals. Bleeding was evaluated based on surgical reports, hemoglobin drop, and the use of blood products or additional PCC during 48 h. Safety measures were thrombotic complications and 30-day mortality. RESULTS: Sixty-two patients aged 80.7 ± 9 years, treated with apixaban (39.63%) or rivaroxaban (23.37%), received PCC before an urgent surgery/procedure. Most underwent abdominal operation (61%), orthopedic surgery (13%), or transhepatic cholecystostomy insertion (10%). Bleeding during surgery was reported in 3 patients (5%), no patient required additional PCC, and 16 patients (26%) received packed cells (median: 1 unit, range: 1-5). The 30-day mortality and thrombosis rates were 21% (n = 13) and 3% (n = 2), respectively. The cause of death was related to the primary disease, most commonly sepsis. No patient died due to bleeding/thrombosis. CONCLUSIONS: Our results support the use of PCC to achieve hemostasis in patients treated with Xa inhibitors prior to an urgent surgery.

Meal intake increases circulating procoagulant microparticles in patients with type 1 and type 2 diabetes mellitus.

Diabetes mellitus (DM) is associated with prothrombotic alterations, and postprandial hyperglycemia is an independent risk factor for cardiovascular complications. We therefore investigated whether a standardized mixed meal alters circulating microparticles (MPs) and their procoagulant activity in DM patients. Patients with DM type 1 (T1DM, n = 11) and type 2 (T2DM; n = 9) were studied before and 90 min after a standardized meal (without premeal insulin). MPs in plasma derived from platelets (PMPs), endothelial cells (EMPs), or monocytes (MMPs) were measured by flow cytometry. MP-induced thrombin generation in plasma was assessed by a calibrated automated thrombogram. In the fasting state, MPs did not differ significantly between T1DM and T2DM. Meal intake increased the following microparticles: PMPs expressing phosphatidylserine (by 55%, on average), P-selectin (by 86%), and tissue factor (TF; by 112%); EMPs expressing E-selectin (by 96%) and MMPs expressing TF (by 164%), with no significant group differences between T1DM and T2DM. There were no increments in EMPs expressing phosphatidylserine or TF. Meal intake increased MP-induced thrombin generation similarly in T1DM and T2DM with increased endogenous thrombin potential (p = 0.02) and peak thrombin (p = 0.03) and shortened time to peak (p = 0.02). Phosphatidylserine inhibition by lactadherin completely abolished MP-induced thrombin generation, while an anti-TF antibody had no effect. In conclusion, meal intake increased several types of circulating MPs in patients with diabetes mellitus. These MPs have a procoagulant potential, which is related to phosphatidylserine expression and negatively charged MP surfaces rather than to TF.

Assessment of procoagulant potential in patients with reactive thrombocytosis and its association with platelet count.

OBJECTIVE: We aimed to determine hemostatic changes and characterize the procoagulant potential among patients with reactive thrombocytosis (RT). METHODS: Sixty patients with RT (median platelet count 718 × 109 /L) and 20 healthy persons were tested for complete blood count, C-reactive protein, von Willebrand factor (VWF), factor VIII and fibrinogen, and thrombin generation. Platelet studies, including light transmission aggregometry and Cone and Plate(let) Analyzer, were also conducted. Reticulated platelets and platelet P-selectin expression were measured using flow cytometry. RESULTS: Compared to patients with mild thrombocytosis (platelet count 500-700 × 109 /L; n = 27), those with moderate-to-severe thrombocytosis (platelet count >700 × 109 /L; n = 33) had significantly higher fibrinogen, factor VIII, and VWF antigen and activity levels; higher endogenous thrombin potential, peak thrombin generation and velocity index levels, and shorter time-to-peak thrombin level. VWF antigen and activity, fibrinogen, and factor VIII were positively associated with platelet count, whereas VWF activity/antigen ratio was inversely correlated. In a multivariate analysis of RT and control participants, only platelet count predicted endogenous thrombin potential with a positive-linear correlation. No patients developed acquired von Willebrand syndrome. CONCLUSIONS: As determined by thrombin generation, RT was associated with in vitro prothrombotic tendency, which correlated with platelet count. This may explain the increased thromboembolic risk previously reported in patients with RT.

Use of a novel chitosan-based dressing on split-thickness skin graft donor sites: a pilot study.

OBJECTIVE: Split-thickness skin graft (STSG) donor site dressings can play an integral role in reducing donor site morbidity. This study tested a novel, chitosan-based wound dressing, Opticell Ag, as an STSG donor site dressing for wounds <10% total body surface area (TBSA). METHOD: Between January and December 2016, the chitosan-based dressing was placed on participating patients' donor sites immediately following graft harvest and covered with a transparent occlusive dressing. Pain was evaluated on postoperative day one, before dressing change between days 5-7, and before and after dressing removal between days 10-14 using the Visual Analog Scale (VAS). The extent of re-epithelialisation was determined between day 10-14 and at one month, and healing quality was also evaluated at one month post-operatively using the Vancouver Scar Scale (VSS). RESULTS: A total of 19 patients were recruited, of which 16 completed the study. Patients experienced mild-to-moderate pain in their donor sites when the chitosan-based dressing was used. Pain decreased significantly between postoperative day one and days 10-14, as well as between days 5-7 and 10-14. The mean percentage of re-epithelialisation on days 10-14 was 92% and by one month was 99%. The mean VSS at one month was 3.2±1.4. There were no statistically significant differences between patients' re-epithelialisation rates or VSS scores. There were unplanned dressing changes in four patients. No donor site infections or other adverse events were identified. CONCLUSION: The chitosan-based dressing tested in this study is safe, effective, and associated with reasonable pain control and acceptable healing quality. The results suggest that it is a promising STSG donor site dressing.

Implementation of an institutional protocol to improve inferior vena cava utilization and outcomes.

To evaluate the impact of an institutional protocol on patterns of use and outcomes of inferior vena cava filters (IVCF). Following a multidisciplinary effort, an institutional protocol involving dedicated follow-up of patients receiving IVCF and a physician education program regarding IVCF utilization, was established. We prospectively collected data of patients who received IVCF during 2015-2016, following protocol implementation (POST group). For comparison, we reviewed records of patients who received IVCF during 2009-2014, before implementation of the institutional protocol (PRE group). In the PRE and POST groups, 76 and 38 IVCF per year were inserted respectively, with an overall decrease of 50%. IVCF were more likely to be placed for therapeutic rather than prophylactic indications in the POST compared to the PRE group (P = 0.003). Follow-up rates at our coagulation clinic were significantly higher in the POST than the PRE group (100 vs. 22.9%, P < 0.0001), as were rates of attempted retrieval: 60.5% (23/38) vs. 16.7% (76/455), P < 0.0001. Failed retrieval occurred at similar rates: 15.8% (12/76) vs. 18.2% (4/22), P = 0.75. There was a trend towards a lower thrombotic complication rate in the POST than the PRE group: 2.6 vs. 11.2%, P = 0.16. Implementation of an institutional protocol significantly decreased the use of IVCF and increased the retrieval rate. Such intervention could potentially lead to lower rates of IVCF-related complications in the future.

Active malignancy in patients with renal vein thrombosis: influence upon clinical course and survival.

BACKGROUND: Renal vein thrombosis (RVT) is a rare event with myriad clinical manifestations. Published experience regarding the clinical course and management of RVT in patients beyond the neonatal period is limited to case reports and small case series. METHODS: A multicenter retrospective review of consecutive admitted patients with diagnosed RVT between January 2000 and May 2015 at three different university hospitals. RESULTS: Thirty-nine patients (53.8 % men and 46.2 % women) were included. Median age was 58 years. Malignancy (n = 19, 48.7 %), nephrotic syndrome (n = 8, 20.5 %) and infection (n = 5, 12.8 %), were the most common underlying conditions. Compared to non-cancer patients, patients with active cancer tended to be significantly older (mean age 63 ± 18 vs. 37 ± 22 years, P = 0.001) and presented with non-acute symptoms (P = 0.01) and unrevealing physical findings (P = 0.02). Thrombosis extension beyond the renal vein occurred in 69.2 % of cases and was more common in cancer patients (P = 0.001). Anticoagulation therapy was administered in 71.8 % of patients leading to resolution of thrombus in most cases (30/32 patients, 94 %) during follow-up evaluation. There were six recurrent thrombotic events during a mean follow-up of 35 ± 43 months. Nine patients (28 %) died during follow-up, all of them with malignancy. CONCLUSION: Active cancer is the most common cause of RVT and should be excluded when RVT is diagnosed. Clinical course of RVT in cancer patients is more indolent and diagnosis requires high index of suspicion. Survival rates are governed by the presence of malignancy.

The macromolecular architecture of platelet-derived microparticles.

Platelets are essential for hemostasis and wound healing. They are involved in fundamental processes of vascular biology such as angiogenesis, tissue regeneration, and tumor metastasis. Upon activation, platelets shed small plasma membrane vesicles termed platelet-derived microparticles (PMPs). PMPs include functional cell adhesion machinery that comprises transmembrane receptors (most abundant are the αIIbß3 integrins), cytoskeletal systems and a large variety of adapter and signaling molecules. Glanzmann thrombasthenia (GT) is a condition characterized by platelets that are deficient of the integrin αIIbß3 heterodimer. Here, we use cryo-electron tomography (cryo-ET) to study the structural organization of PMPs (in both healthy and GT patients), especially the cytoskeleton organization and receptor architecture. PMPs purified from GT patients show a significantly altered cytoskeletal organization, characterized by a reduced number of filaments present, compared to the healthy control. Furthermore, our results show that incubating healthy PMPs with manganese ions (Mn(2+)), in the presence of fibrinogen, induces a major conformational change of integrin receptors, whereas thrombin activation yields a moderate response. These results provide the first insights into the native molecular organization of PMPs.

Thrombophilic state in young patients with acute myocardial infarction.

The prevalence of thrombophilia and dyslipidemia among young survivors of acute coronary syndrome has not been clearly defined. The purpose of the current study was to investigate the prevalence of multiple markers of thrombophilia and dyslipidemia in a cohort of consecutive young survivors of acute coronary syndrome. The study cohort included 156 consecutive young patients (men <45 and women <50 years), admitted to the intensive cardiac care unit with newly diagnosed acute coronary syndrome. Analysis included baseline, clinical and epidemiological characteristics, angiographic coronary anatomy, echocardiographic evaluation, extensive lipid and thrombophilia laboratory profiles, and in-hospital and 1-year clinical outcomes for all patients. Acute myocardial infarction was diagnosed in 142 (92 %) patients, of whom 108 (72 %) had ST-segment elevation. Eighteen (12 %) patients had no traditional risk factors. Low levels of high-density lipoprotein (<40 mg/dL) were found in 101 (65 %) patients, and 49 (34 %) patients had elevated levels of lipoprotein(a) (Lp(a)) (>30 mg/dL). Eighteen (12 %) patients were diagnosed with antiphospholipid antibody syndrome (APS), and 73 (47 %) had at least one laboratory finding consistent with thrombophilia. Patients with APS had significantly higher levels of Lp(a) (46 ± 32 vs. 29 ± 31 mg/dL, p = 0.005). APS is a common prothrombotic state found in young survivors of acute coronary syndrome. Lp(a) levels are elevated among APS patients who present with premature acute coronary syndrome.

Evaluation of platelet response to different clopidogrel dosing regimens in patients with acute coronary syndrome in clinical practice.

High-post clopidogrel platelet reactivity in acute coronary syndrome (ACS) patients is associated with adverse outcomes and may be related to clopidogrel dosing. Clinical studies evaluating different clopidogrel doses have resulted in conflicting conclusions. Clopidogrel dosing regimens have evolved over time, enabling us to evaluate platelet reactivity in real-life ACS patients undergoing percutaneous coronary intervention and treated with three different clopidogrel doses. Platelet reactivity was assessed with light transmitted aggregometry on the third day post clopidogrel loading in 404 consecutive ACS patients. Of them, 198 were treated with a standard regimen (300 mg loading, 75 mg/day maintenance dose), 95 with a high loading regimen (600 mg loading, 75 mg/day maintenance dose) and 111 with a high loading/high maintenance regimen (600 mg loading, 150 mg/day maintenance). Compared with the standard regimen, the high loading regimen resulted in significantly lower mean platelet reactivity to adenosine diphosphate (ADP) with a lower proportion of patients exhibiting clopidogrel non-responsiveness (11% vs. 28%, p = 0.004). Compared with the high loading regimen, the high loading/high maintenance regimen resulted in significantly lower mean platelet reactivity to ADP, but without a further drop in the number of non-responders (8.1% vs. 11%, p = 0.16). In conclusion, greater overall inhibition can be achieved with higher loading and maintenance doses in ACS patients. However, despite high clopidogrel doses, a sizable proportion of patients remained "resistant" to the effects of clopidogrel.

[Pulmonary embolism in athletes--a surprising diagnosis].

Pulmonary embolus is considered a rare and surprising event in the athletic population. Failure to diagnose this condition may lead to serious morbidity and even death. We report a case series of athletes diagnosed at the Acute Diagnostic Unit over the last two years, and discuss the special diagnostic, mechanistic and treatment principles in this population. We hope that this article will increase awareness of this condition amongst the medical teams dealing with this super fit population.

Bimodal response to aspirin loading in acute ST-elevation myocardial infarction.

Patients with stable coronary disease who exhibit platelet hypo-responsiveness to aspirin (ASA) have worse outcomes. Little data exist regarding platelet response to ASA in ST-elevation myocardial infarction (STEMI) patients. Our objective was to assess acute platelet response to ASA loading in STEMI patients undergoing primary percutaneous coronary intervention (PCI). The study comprised 102 consecutive patients with STEMI. All patients received a loading dose of 300 mg chewable ASA upon admission. Platelet reactivity was assessed immediately prior to primary PCI, at a median of 95(63 139) minutes after ASA loading. A bimodal response to arachidonic acid (AA) stimulation was observed, such that two distinct populations could be discerned: "good responders" had a mean AA-induced platelet aggregation of 36 ± 11% vs. 79 ± 9% for "poor responders." Despite equivalent demographic, clinical, and angiographic characteristics, good responders were significantly more likely to demonstrate early ST-segment resolution ≥70% after primary PCI (80% vs. 48%, p = 0.001), suggestive of better myocardial reperfusion. Early inhibition of AA-induced platelet aggregation post-ASA loading in the setting of STEMI is associated with better tissue reperfusion; however, a sizeable proportion of patients do not achieve significant inhibition of AA-induced platelet aggregation in response to ASA loading at the time of primary PCI.

Testicular catch-up growth in the non-operative management of the adolescent varicocele.

INTRODUCTION: Adolescent varicocele is a common urologic condition with a spectrum of outcomes, leading to variations in management. Testicular hypotrophy is a common indication for surgery Routine monitoring may be an appropriate form of management for many adolescents with testicular hypotrophy, as studies have shown that a large proportion of these patients may experience catch-up growth of the ipsilateral testis. Furthermore, there are few longitudinal studies which have correlated patient specific factors to catch-up growth. We aimed to determine the frequency of testicular catch up-growth in adolescents with varicocele while also examining if patient specific factors such as BMI, BMI percentile, or height correlated with testicular catch-up growth. METHODS: A retrospective chart review found adolescent patients who presented to our institution with varicocele from 1997 to 2019. Patients between the ages of 9 and 20 years with left-sided varicocele, a clinically significant testicular size discrepancy, and at least two scrotal ultrasounds at least one year apart were included in analysis. Testicular size discrepancy of greater than 15% on scrotal ultrasound was considered clinically significant. Testicular size was estimated in volume (mL) via the Lambert formula. Statistical relationships between testicular volume differential and height, body mass index (BMI), and age were described with Spearman correlation coefficients (ρ). RESULTS: 40 patients had a testicular volume differential of greater than 15% at some point during their clinical course and were managed non-operatively with observation and serial testicular ultrasounds. On follow-up ultrasound, 32/40 (80%) had a testicular volume differential of less than 15%, with a mean age of catch up growth at 15 years (SD 1.6, range 11-18 years). There were no significant correlations between baseline testicular volume differential and baseline BMI (ρ = 0.00, 95% CI [-0.32, 0.32]), baseline BMI percentile (ρ = 0.03, 95% CI [-0.30, 0.34]), or change in height over time (ρ = 0.05, 95% CI [-0.36, 0.44]). DISCUSSION: The majority of adolescents with varicocele and testicular hypotrophy exhibited catch-up growth with observation, suggesting that surveillance is an appropriate form of management in many adolescents. These findings are consistent with previous studies and further indicate the importance of observation for the adolescent varicocele. Further research is warranted to determine patient specific factors that correlate with testicular volume differential and catch up growth in the adolescent varicocele.

Evaluation of Topical Off-The-Shelf Therapies to Improve Prolonged Field Care of Burn-Injured Service Members.

INTRODUCTION: Burns are common injuries on the battlefield. Given austere environments, surgical debridement of injured service members is often not feasible in these settings. Delays in surgical debridement create a risk of infection and deranged healing for burn patients. As such, this study attempts to identify the best commercially available off-the-shelf (OTS) therapies with field-deployable potential to improve prolonged field care (PFC) of burn-injured soldiers. METHODS: Deep partial-thickness (DPT) burns (25 cm2) were created on the dorsum of 5 anesthetized pigs utilizing a thermocouple burn device at 100°C for 15 seconds. Nonsurgical debridement was done 1-hour after burn creation using sterile saline water and gauze to remove excess eschar tissue. Animals were then randomized into 5 experimental groups, and OTS therapies were applied to 6 of the 12 created DPT burns. The remaining 6 burns were treated with 1% silver sulfadiazine cream (Ascend Laboratories, LLC, Parsippany, NJ) as the PFC standard of care (SOC) controls. The 5 randomized OTS therapies were: irradiated sterile human skin allograft (IHS), biodegradable temporizing matrix (BTM), polylactic acid skin substitute, hyaluronic acid ester matrix (HAM), and decellularized fish skin graft (FSG). Wounds were serially assessed on post-burn days 3, 7, 14, 21, and 28. Assessments were conducted using a combination of photographs, histology, and quantitative bacteriology. Endpoints included burn wound progression, re-epithelialization, wound contraction, scar elevation index, and colony-forming units (CFU). RESULTS: The analysis demonstrated that by day 3, the FSG prevented burn wound progression the most efficiently. In terms of wound healing, the results showed re-epithelialization percentages close to 100% by day 28 for all treatment groups. No statically significant differences were observed. Quality of healing analyses demonstrated that the BTM-treated wounds had contracted less and the difference to the IHS-treated wounds was statistically significant (P < .05). As regards to antimicrobial properties, the CFU results showed no statistically significant differences between the OTS therapies and the SOC on days 3, 7, and 14. CONCLUSIONS: The impact of Food and Drug Administration-approved OTS therapies was compared to the current PFC SOC for the treatment of DPT burns in a porcine model. Several topical options exist for the management of burns prior to definitive treatment in the operating room and warrant further evaluation. These therapies are actively used on civilian burn counterparts and have far-forward, field-deployable potential for use at the point of injury so that injured service members may not need evacuation to higher roles of care and combat power may be preserved. Our results demonstrated that all the studied OTS therapies performed well when compared to the SOC in terms of burn wound progression, wound healing, quality of healing, and quantitative bacteriology.

Underdiagnosed menorrhagia in adolescents is associated with underdiagnosed anemia.

OBJECTIVE: To test the hypothesis that adolescent girls with menorrhagia rarely seek medical attention. STUDY DESIGN: A total of 705 adolescent girls attended a lecture on menorrhagia, completed an initial anonymous questionnaire, and were asked to participate in a more comprehensive study comprising a detailed bleeding questionnaire, a pictorial blood loss assessment chart, and blood tests. RESULTS: A total of 105 adolescents (15%) reported they had heavy periods on the initial questionnaire. Among the 94 girls who completed the full questionnaire, 34 reported menorrhagia (36%; 95% CI, 26.5%-46.7%). Almost one-third (11 of 34) of these girls did not perceive having menorrhagia according to their response to the initial questionnaire. Menorrhagia was not related to age, years since menarche, or family history of menorrhagia. Among the 62 girls who consented to blood testing, 6 had anemia (9.6%; 95% CI, 3.6%-19.6%), all of whom had bleeding symptoms. CONCLUSION: Using standardized questionnaires, we were able to identify adolescents with menorrhagia associated with anemia. Importantly, some of these adolescents were not aware of having menorrhagia and/or anemia. Screening programs for menorrhagia in schools could result in better detection of menorrhagia among adolescents and consequent appropriate referral for medical consultation.

Development, cell differentiation, angiogenesis--microparticles and their roles in angiogenesis.

Cells of various types release small membrane vesicles called microparticles (MP) on their activation, as well as during the process of apoptosis. The properties and roles of MP generated in different contexts are diverse and are determined by their parent cell and the pathway of their generation, which affects their content. MP are involved in multiple cellular functions, including immunomodulation, inflammation, coagulation, and intercellular communication. MP are able to deliver molecular signals in the form of lipids, proteins, nucleic acids, or functional transmembrane proteins from the parent cell to distantly located targets. In this review, we summarize some of the current knowledge regarding MP and their functional roles in transfer of proteins, nucleic acids, and signal transduction stimulators between cells of different origins in different settings. We will focus on the ability of MP to mediate angiogenesis-related signals and their effect on cell development. The investigation of MP could elucidate new cellular communication pathways and may lead to better understanding of pathophysiological processes. From a clinical point of view, MP may serve as biomarkers for disease status and may be found useful for developing novel therapeutic strategies targeting angiogenesis-related conditions.

Brachial artery endothelial function predicts platelet function in control subjects and in patients with acute myocardial infarction.

Platelet activation occurs in an endothelium-dependent flow-mediated dilation (FMD) impairment environment. The aim of this study was to explore the association between platelet reactivity and brachial artery FMD in individuals without established cardiovascular disease (controls) and acute myocardial infarction (AMI) patients. We prospectively assessed brachial artery FMD in 151 consecutive subjects, 104 (69%) controls, and 47 (31%) AMI patients; 115 (76%) men, mean age 53 ± 11 years. Following overnight fasting and discontinuation of all medications for ≥ 12 h, percent change in brachial artery FMD (%FMD) and endothelium-independent, nitroglycerin-mediated vasodilation (%NTG) were assessed. Platelet aggregation was assessed by conventional aggregometry, and platelet adhesion and aggregation under flow conditions by cone-and-plate(let) technology (Impact-R). Smoking, diabetes, and hypertension were more common in AMI compared to control subjects (p < 0.01 for all). Furthermore, aspirin, clopidogrel, beta-blockers, angiotensin-converting enzyme inhibitors, and statin administration were more common in AMI compared to controls (p < 0.01 for all). %FMD but not %NTG was significantly lower in AMI patients compared to controls (10.2 ± 4.2% vs. 15.4 ± 4.4%; p < 0.001 and 17.2 ± 3.9% vs. 18.0 ± 3.7%, p = 0.803, respectively). %FMD was significantly and inversely associated with all platelet functions tests (p < 0.001) in all study participants. In a multivariate logistic regression (unadjusted and adjusted for age, gender, smoking status, diabetes mellitus, hypertension, hypercholesterolemia, overweight, family history, and concomitant medications), %FMD remained the best predictor of platelet function, irrespective of group allocation (AMI patients or controls). In conclusion, FMD is inversely correlated to platelet reactivity in both controls and AMI patients.