A case of acquired transient bleeding diathesis associated with acquired platelet storage pool deficiency and defective thromboxane A2 production.

Acquired disorders of platelet function are an underdiagnosed cause of bleeding tendency. A 14-year-old girl developed moderate mucocutaneous bleeding two weeks after a Mycoplasma pneumoniae infection successfully treated with clarithromycin. The patient was referred to us 7 months later for laboratory investigation of the persisting bleeding diathesis. The patient's personal and family histories were negative for bleeding disorders. Complete blood count, von Willebrand Factor levels and coagulation tests were normal; platelet aggregation, ATP secretion, δ-granules content and serum thromboxane B2 levels were defective. At follow-up visits, laboratory parameters and the bleeding diathesis progressively normalized within 2 years. The patient's condition is compatible with a diagnosis of acquired Storage Pool Deficiency (SPD), associated with defective thromboxane A2 production. To our knowledge, this is the first case of acquired, transient SPD with spontaneous remission. The pathogenic role of Mycoplasma pneumoniae infection or clarithromycin is possible, albeit uncertain.

Long-Term Outcomes in Two-Year Follow-Up after Primary Treatment in Patients with a Prior Venous Thromboembolic Event: A Prospective, Observational, Real-Life Study.

BACKGROUND: Patients with acute venous thromboembolism (VTE) need anticoagulation (AC) therapy for at least 3/6 months (primary treatment); after that period, they should receive a decision on the duration of therapy. METHODS: This study examined the complications occurring during two years of follow-up (FU) in patients with a first VTE who were recruited in 20 clinical centers and had discontinued or prolonged AC. They were included in the START2-POST-VTE prospective observational study. RESULTS: A total of 720 patients (53.5% males) who, after the completion of primary treatment, had received the decision to continue (n = 281, 39%; 76.1% with a DOAC) or discontinue (n = 439, 61%) AC were followed up for 2 years (total FU = 1318 years). The decision to prolong or suspend AC was made in similar proportions in patients with unprovoked or provoked index events. Courses of sulodexide treatment or Aspirin (100 mg daily) were prescribed to 20.3% and 4.5%, respectively, of the patients who discontinued AC. The bleeding rate was significantly higher in patients who extended AC (1.6% pt/y) than in those who stopped AC (0.1% pt/y; p = 0.001) and was higher in patients using standard-dose DOACs (3.1% pt/y) than in those using reduced-dose DOACs (0.4% pt/y). The recurrent VTE rates were similar between the two groups (2.2% pt/y during AC vs. 3% pt/y off AC). CONCLUSION: Physicians' decisions about AC duration were independent of the unprovoked/provoked nature of the index event. The bleeding rate was higher in patients who continued AC using standard-dose DOACs. Surprisingly, the rate of thrombotic recurrence was not different between those who continued or discontinued AC. Randomized studies comparing different procedures to decide on the duration of AC after a first VTE are needed.

Thrombosis and Bleeding in Patients with Vaccine-Induced Immune Thrombotic Thrombocytopenia: A Systematic Review of Published Cases.

INTRODUCTION: Vaccine-induced immune thrombotic thrombocytopenia (VITT) is a highly prothrombotic reaction to COVID-19 (coronavirus disease 2019) adenoviral vector vaccines. Its distinct bleeding and thrombotic patterns compared with other platelet consumptive disorders remain unclear. METHODS: We performed a systematic review of the literature (PubMed and Embase) up to July 31, 2022, including case reports and case series providing nonaggregate data of VITT patients. Accurate VITT diagnosis required fulfillment of the following criteria: (1) endorsement by the authors, (2) consistent vaccine type and timing, (3) presence of thrombocytopenia and thrombosis, (4) detection of anti-platelet factor 4 antibodies. Data are presented as frequencies with 95% confidence intervals (CIs) calculated with the exact binomial method. RESULTS: We retrieved 143 eligible studies, describing 366 patients. Of 647 thrombotic events, 53% (95% CI: 49-56) were venous thromboses at unusual sites and 30% (95% CI: 27-34) were cerebral venous sinus thromboses (CVSTs). The ratio of venous-to-arterial events was 4.1. Thromboses in most sites were associated with at least another thrombotic event, with the exception of CVST and CNS arterial thrombosis (isolated in 49 and 39% of cases, respectively). Bleeding occurred in 36% (95% CI: 31-41) of patients; 68% (95% CI: 59-75) of bleeding events were intracranial hemorrhages (ICHs). Overall mortality was 24% (95% CI: 19-29), and 77% (95% CI: 58-90) in patients with isolated CVST complicated by ICH. CONCLUSION: VITT displays a venous-to-arterial thrombosis ratio comparable to heparin-induced thrombocytopenia. However, VITT is characterized by a higher prevalence of CVST and ICH, which contribute to the increased bleeding frequency and mortality.

Caplacizumab use for immune thrombotic thrombocytopenic purpura: the Milan thrombotic thrombocytopenic purpura registry.

•Data on caplacizumab use for thrombotic thrombocytopenic purpura (TTP) in Italy are missing.•Twenty-six Italian patients were treated with caplacizumab for an acute immune TTP episode.•Caplacizumab was effective in treating acute TTP in the Italian real-world clinical setting.•Two major bleeds leading to drug discontinuation were observed.

Cell Surface Platelet Tissue Factor Expression: Regulation by P2Y12 and Link to Residual Platelet Reactivity.

BACKGROUND: ADP-induced platelet activation leads to cell surface expression of several proteins, including TF (tissue factor). The role of ADP receptors in platelet TF modulation is still unknown. We aimed to assess the (1) involvement of P2Y1 and P2Y12 receptors in ADP-induced TF exposure; (2) modulation of TFpos-platelets in anti-P2Y12-treated patients with coronary artery disease. Based on the obtained results, we revisited the intracellular localization of TF in platelets. METHODS: The effects of P2Y1 or P2Y12 antagonists on ADP-induced TF expression and activity were analyzed in vitro by flow cytometry and thrombin generation assay in blood from healthy subjects, P2Y12-/-, and patients with gray platelet syndrome. Ex vivo, P2Y12 inhibition of TF expression by clopidogrel/prasugrel/ticagrelor, assessed by VASP (vasodilator-stimulated phosphoprotein) platelet reactivity index, was investigated in coronary artery disease (n=238). Inhibition of open canalicular system externalization and electron microscopy (TEM) were used for TF localization. RESULTS: In blood from healthy subjects, stimulated in vitro by ADP, the percentage of TFpos-platelets (17.3±5.5%) was significantly reduced in a concentration-dependent manner by P2Y12 inhibition only (-81.7±9.5% with 100 nM AR-C69931MX). In coronary artery disease, inhibition of P2Y12 is paralleled by reduction of ADP-induced platelet TF expression (VASP platelet reactivity index: 17.9±11%, 20.9±11.3%, 40.3±13%; TFpos-platelets: 10.5±4.8%, 9.8±5.9%, 13.6±6.3%, in prasugrel/ticagrelor/clopidogrel-treated patients, respectively). Despite this, 15% of clopidogrel good responders had a level of TFpos-platelets similar to the poor-responder group. Indeed, a stronger P2Y12 inhibition (130-fold) is required to inhibit TF than VASP. Thus, a VASP platelet reactivity index <20% (as in prasugrel/ticagrelor-treated patients) identifies patients with TFpos-platelets <20% (92% sensitivity). Finally, colchicine impaired in vitro ADP-induced TF expression but not α-granule release, suggesting that TF is open canalicular system stored as confirmed by TEM and platelet analysis of patients with gray platelet syndrome. CONCLUSIONS: Data show that TF expression is regulated by P2Y12 and not P2Y1; P2Y12 antagonists downregulate the percentage of TFpos-platelets. In clopidogrel good-responder patients, assessment of TFpos-platelets highlights those with residual platelet reactivity. TF is stored in open canalicular system, and its membrane exposure upon activation is prevented by colchicine.

Impairment of platelet function in both mild and severe COVID-19 patients.

Abnormalities of platelet function were reported in patients with severe COVID-19 (severe-C), but few data are available in patients with mild COVID-19 (mild-C) and after COVID-19 recovery. The aim of this study was to investigate platelet parameters in mild-C patients (n = 51), with no evidence of pneumonia, and severe-C patients (n = 49), during the acute phase and after recovery, compared to 43 healthy controls. Both mild-C and severe-C patients displayed increased circulating activated platelets, low δ-granule content (ADP, serotonin), impaired platelet activation by collagen (light transmission aggregometry) and impaired platelet thrombus formation on collagen-coated surfaces under controlled flow conditions (300/s shear rate). The observed abnormalities were more marked in severe-C patients than in mild-C patients. Overall, 61% (30/49) of mild-C and 73% (33/45) of severe-C patients displayed at least one abnormal platelet parameter. In a subgroup of just 13 patients who showed no persisting signs/symptoms of COVID-19 and were re-evaluated at least 1 month after recovery, 11 of the 13 subjects exhibited normalization of platelet parameters. In conclusion, mild abnormalities of platelet parameters were present not only in severe-C but also, albeit to a lesser extent, in mild-C patients during the acute phase of COVID-19 and normalized in most tested patients after clinical recovery.

Guided Anti-P2Y12 Therapy in Patients Undergoing PCI: Three Systematic Reviews with Meta-analyses of Randomized Controlled Trials with Homogeneous Design.

BACKGROUND: The value of guided therapy (GT) with anti-P2Y12 drugs in percutaneous coronary intervention (PCI) is unclear. Meta-analyses lumped together randomized controlled trials (RCTs) with heterogeneous designs, comparing either genotype-GT or platelet function test (PFT)-GT with unguided therapy. Some meta-analysis also included RCTs that did not explore GT, but included the effects of switching patients with high on-treatment platelet reactivity (HTPR) to alternative therapies (HTPR-Therapy). We performed three distinct systematic reviews/meta-analyses, each exploring only RCTs with homogeneous design. METHODS: MEDLINE, Embase, and Central databases were searched for RCTs testing genotype-GT, PFT-GT, or HTPR-Therapy in PCI-treated patients, through October 1, 2022. Two reviewers extracted the data. Risk ratios (RRs) (95% confidence intervals) were calculated. Primary outcomes were major bleedings (MBs) and major adverse cardiovascular events (MACE). RESULTS: In seven genotype-GT RCTs, RRs were: MB, 1.06 (0.73-1.54; p = 0.76); MACE, 0.65 (0.47-0.91; p = 0.01), but significant risk reduction was observed in RCTs performed in China (0.30, 0.16-0.54; p < 0.0001) and not elsewhere (0.75, 0.48-1.18; p = 0.21). In six PFT-GT RCTs, RRs were: MB, 0.91 (0.64-1.28, p = 0.58); MACE, 0.82 (0.56-1.19; p = 0.30): 0.62 (0.42-0.93; p = 0.02) in China, 1.08 (0.82-1.41; p = 0.53) elsewhere. In eight HTPR-Therapy RCTs, RRs were: MB, 0.71 (0.41-1.23; p = 0.22); MACE, 0.57 (0.44-0.75; p < 0.0001): 0.56 (0.43-0.74, p < 0.0001) in China, 0.58 (0.27-1.23, p = 0.16) elsewhere. CONCLUSION: No GT strategy affected MB. Overall, genotype-GT but not PFT-GT reduced MACE. However, genotype-GT and PFT-GT reduced MACE in China, but not elsewhere. PFT-GT performed poorly compared to HTPR-Therapy, likely due to inaccurate identification of HTPR patients by PFT.

SEM Evaluation of Thermal Effects Produced by a 445 nm Laser on Implant Surfaces.

The aim of this in vitro study was to evaluate thermal effects on implant surfaces using a 445 nm diode laser (Eltech K-Laser Srl, Treviso, Italy) with different power settings and irradiation modalities. Fifteen new implants (Straumann, Basel, Switzerland) were irradiated to evaluate surface alteration. Each implant was divided into two zones: the anterior and posterior areas. The anterior coronal areas were irradiated with a distance of 1 mm between the optical fiber and the implant; the anterior apical ones were irradiated with the fiber in contact with the implant. Instead, the posterior surfaces of all of the implants were not irradiated and used as control surfaces. The protocol comprised two cycles of laser irradiation, lasting 30 s each, with a one-minute pause between them. Different power settings were tested: a 0.5 W pulsed beam (T-on 25 ms; T-off 25 ms), a 2 W continuous beam and a 3 W continuous beam. Lastly, through a scanning electron microscopy (SEM) analysis, dental implants' surfaces were evaluated to investigate surface alterations. No surface alterations were detected using a 0.5 W laser beam with a pulsed mode at a distance of 1 mm. Using powers of irradiation of 2 W and 3 W with a continuous mode at 1 mm from the implant caused damage on the titanium surfaces. After the irradiation protocol was changed to using the fiber in contact with the implant, the surface alterations increased highly compared to the non-contact irradiation modality. The SEM results suggest that a power of irradiation of 0.5 W with a pulsed laser light emission mode, using an inactivated optical fiber placed 1 mm away from the implant, could be used in the treatment of peri-implantitis, since no implant surface alterations were detected.

Venous thromboembolism secondary to hospitalization for COVID-19: patient management and long-term outcomes.

Background: Venous thromboembolism (VTE) is a complication of COVID-19 in hospitalized patients. Little information is available on long-term outcomes of VTE in this population. Objectives: We aimed to compare the characteristics, management strategies, and long-term clinical outcomes between patients with COVID-19-associated VTE and patients with VTE provoked by hospitalization for other acute medical illnesses. Methods: This is an observational cohort study, with a prospective cohort of 278 patients with COVID-19-associated VTE enrolled between 2020 and 2021 and a comparison cohort of 300 patients without COVID-19 enrolled in the ongoing START2-Register between 2018 and 2020. Exclusion criteria included age <18 years, other indications to anticoagulant treatment, active cancer, recent (<3 months) major surgery, trauma, pregnancy, and participation in interventional studies. All patients were followed up for a minimum of 12 months after treatment discontinuation. Primary end point was the occurrence of venous and arterial thrombotic events. Results: Patients with VTE secondary to COVID-19 had more frequent pulmonary embolism without deep vein thrombosis than controls (83.1% vs 46.2%, P <.001), lower prevalence of chronic inflammatory disease (1.4% and 16.3%, P <.001), and history of VTE (5.0% and 19.0%, P <.001). The median duration of anticoagulant treatment (194 and 225 days, P = 0.9) and the proportion of patients who discontinued anticoagulation (78.0% and 75.0%, P = 0.4) were similar between the 2 groups. Thrombotic event rates after discontinuation were 1.5 and 2.6 per 100 patient-years, respectively (P = 0.4). Conclusion: The risk of recurrent thrombotic events in patients with COVID-19-associated VTE is low and similar to the risk observed in patients with VTE secondary to hospitalization for other medical diseases.

Assessment of post-partum haemorrhage risk among women with moderate thrombocytopenia.

It is unknown whether moderate thrombocytopenia represents a risk factor for post-partum haemorrhage (PPH). We assessed PPH risk among women with a platelet count of between 100 and 50 × 109 /l and stratified the risk for O/non-O blood group. We included consecutive women undergoing vaginal delivery or caesarean section with moderate thrombocytopenia. Women with >150 × 109 /l platelets at delivery were selected as controls and matched for age, type of birth and ethnicity. Odds ratios (ORs) with their 95% confidence intervals (95% CIs) were calculated as risk estimates. A total of 94 thrombocytopenic women and 94 controls were included in the study. The rate of PPH was significantly higher in thrombocytopenic women than in controls (37% vs. 10%, p < 0.001); there was a higher risk of PPH in the thrombocytopenic group when compared to the control group (adjusted OR 4.7, 95% CI 2.1-10.8, p < 0.01) and this association was stronger in blood group O carriers (adjusted OR 11.0, 95% CI 2.4-49.6, p < 0.01). In conclusion, our study shows that a moderate thrombocytopenia is a risk factor for PPH, especially in blood group O carriers.

Refractory primary immune thrombocytopenia (ITP): current clinical challenges and therapeutic perspectives.

Chronic primary immune thrombocytopenia (ITP) can today benefit from multiple therapeutic approaches with proven clinical efficacy, including rituximab, thrombopoietin receptor agonists (TPO-RA), and splenectomy. However, some ITP patients are unresponsive to multiple lines of therapy with prolonged and severe thrombocytopenia. The diagnosis of refractory ITP is mainly performed by exclusion of other disorders and is based on the clinician's expertise. However, it significantly increases the risk of drug-related toxicity and of bleedings, including life-threatening events. The management of refractory ITP remains a major clinical challenge. Here, we provide an overview of the currently available treatment options, and we discuss the emerging rationale of new therapeutic approaches and their strategic combination. Particularly, combination strategies may target multiple pathogenetic mechanisms and trigger additive or synergistic effects. A series of best practices arising both from published studies and from real-life clinical experience is also included, aiming to optimize the management of refractory ITP.

[10 years of stagnant clinical research in the Italian academic context.] / Dieci anni di stagnazione della ricerca, non solo clinica, nel contesto accademico italiano.

This article is about current challenges to evidence-based medicine (EMB) in Italy. The authors, who share a 20-year commitment to the field of clinical research, discuss what they define as a phase of "stagnation" in practicing and teaching methods and research tactics, both in clinical and academic settings. Early success of EBM cultural movement was not persistent. The authors reason about how the teaching of EBM has remained a niche, concerning few professionals compared to the needs of the country. The authors identify some reasons that might have led to inconsistent attention to research methodology and address ways to strengthen the contribution of academic medicine to clinical research.

Treatment of immune thrombocytopenia (ITP) secondary to malignancy: a systematic review.

Immune thrombocytopenia (ITP) can be associated with lymphoproliferative diseases (LPD) or solid tumors. A systematic review of published literature was conducted to evaluate response to treatment of ITP secondary to malignancy. Primary outcome was overall response (complete response+response) to first-line treatments [steroids alone or in combination with intravenous immunoglobulins (IVIg)]. Among secondary outcomes, overall response to second-line treatments [splenectomy, rituximab or thrombopoietin receptor agonists (TPO-RA)] and death were evaluated. Of the retrieved 238 text articles, 108 were analyzable, for a total of 154 patients: 142 in 105 case reports and 12 in 3 observational studies. Thirty-nine patients had solid tumors, 114 LPD, and 1 both. The median follow up was 19 months (IQR, 9-40). The overall response was 50% (62% in solid tumors, 46% in LPD) after steroids and 47% (67% in solid tumors, 36% in LPD) after steroids+IVIg, which are lower than historical responses observed in primary ITP (≈80%). The overall responses to rituximab (used in LPD only), splenectomy and TPO-RA (70%, 73% and 92%, respectively) were similar to those observed in primary ITP. Seven patients (6%) died due to bleeding events. ITP secondary to malignancy appears to be associated with unsatisfactory response to first-line treatments.