Six-week low-molecular-weight heparin versus 12-week warfarin for calf deep vein thrombosis: A randomized, prospective, open-label study.

Current guidelines suggest a 3-month anticoagulant treatment course for isolated distal deep vein thrombosis (IDDVT), but shorter durations of treatment are frequently prescribed in clinical practice. We investigated whether a 6-week treatment with low-molecular-weight heparin (LMWH) at intermediate dosage can be an effective and safe alternative to vitamin K antagonists (VKA) in patients with IDDVT (non-inferiority trial). In a multicenter, open-label, randomized trial, 260 outpatients with symptomatic IDDVT were randomly assigned to receive either LMWH followed by VKA for 12 weeks or LMWH 1 mg/kg subcutaneously twice a day for 2 weeks followed by 1 mg/kg subcutaneously once a day for 4 weeks. The follow-up was 6 months and the primary endpoint was the composite measure of recurrent venous thromboembolism (VTE) defined as: recurrence or extension of IDDVT, proximal DVT, and pulmonary embolism (PE). The study was stopped prematurely due to slow recruiting rates. The primary efficacy outcome occurred in 14 patients receiving LMWH (10.8%) and in five patients receiving VKA (3.8%); risk difference was 0.069 (95% CI: 0.006-0.132), hazard ratio 2.8 (95% CI: 1.04-7.55). There was one PE in the VKA group and one proximal DVT in the LMWH group. IDDVT recurrence was 10.0% in the LMWH group versus 3.1% in the VKA group (p = .024). Two patients had clinically relevant bleedings (1.6%) in the LMWH group versus one (0.8%) in VKA group (p = .56). In conclusion, VKA for 12 weeks seems superior to LMWH for 6 weeks in reducing the risk of VTE recurrences in our cohort of outpatients with IDDVT.

Update on the Pharmacological Actions of Enoxaparin in Nonsurgical Patients.

Low-molecular-weight heparins are a class of drugs derived from the enzymatic depolymerization of unfractionated heparin that includes enoxaparin. Several studies have been performed on enoxaparin in recent years, in particular for the prevention and treatment of venous thromboembolism and for the treatment of acute coronary syndrome. Furthermore, the use of enoxaparin has been extended to other clinical situations that require antithrombotic pharmacological prevention, such as hemodialysis and recurrent abortion. In this review, we report the main clinical experiences of using enoxaparin in the prevention of VTE in nonsurgical patients.

Common Practice in the Treatment of Superficial Vein Thrombosis Involving the Sapheno-Femoral Junction: Results from a National Survey of the Italian Society of Angiology and Vascular Medicine (SIAPAV).

Background and Objectives: Prophylactic doses of low-molecular-weight heparins or fondaparinux showed their efficacy and safety for treatment of all superficial vein thrombosis (SVT) of the lower limbs, yet not for those extended to the last 3 cm of the great saphenous vein, close to the sapheno-femoral junction, or considered as a deep-vein thrombosis. Some experts suggest that these patients should be managed with full anticoagulant doses but evidence to support this recommendation is lacking, suggesting the need for a properly designed trial. Materials and Methods: Before starting a new trial, the Italian Society of Angiology and Vascular Medicine (SIAPAV) decided to verify the common therapeutic approaches for patients with an SVT in Italian vascular centers based on a hypothetical significant variation in each daily clinical practice. A standardized questionnaire of 10 questions was administered to all SIAPAV affiliates by means of the official Society website. Results: From 1 December 2022 to 20 January 2023 a total of 191 members (31.8%) answered the questionnaire, showing a detailed and a substantial heterogeneity in the therapeutic approach to SVT patients among experienced vascular physicians and angiologists. Detailed results are reported in the relative section. Conclusions: The therapeutic approach of SVT extended to the iuxta-femoral segment of the great saphenous vein is still a matter of debate, and data to support therapeutic strategies are lacking. The wide heterogeneity in the management of SVT patients, including those with more extended thrombosis, confirmed that a randomized controlled clinical trial investigating the efficacy and the safety of a tailored therapeutic regimen in this particular subgroup of patients is strongly warranted.

Pathophysiology of Vaccine-Induced Prothrombotic Immune Thrombocytopenia (VIPIT) and Vaccine-Induced Thrombocytopenic Thrombosis (VITT) and Their Diagnostic Approach in Emergency.

SARS-CoV-2 induced a pandemic that is reported to have started in Asia and was then extended to other countries in the world. Main clinical aspects of this viral infection have been lung injuries with severe pneumonia requiring prolonged hospitalization and associated morbidities such as venous thromboembolism and/or superinfection by bacteria, fungus or other pests. Immediately there was a need to develop a sustainable therapeutic strategy, such as vaccination. Vaccines against Covid-19, in fact, exert a protective action for common people and reduce viral diffusion. Yet, vaccination of a large number of people raises the question of a well-known complication of several types of vaccines; this complication is immune thrombocytopenia, which is sometimes associated with thrombosis as well. In this short review, we summarized mechanisms involved in the pathogenesis of vaccine-induced prothrombotic immune thrombocytopenia and vaccine-induced thrombocytopenic thrombosis.

Safety and feasibility of a diagnostic algorithm combining clinical probability, d-dimer testing, and ultrasonography for suspected upper extremity deep venous thrombosis: a prospective management study.

BACKGROUND: Although well-established for suspected lower limb deep venous thrombosis, an algorithm combining a clinical decision score, d-dimer testing, and ultrasonography has not been evaluated for suspected upper extremity deep venous thrombosis (UEDVT). OBJECTIVE: To assess the safety and feasibility of a new diagnostic algorithm in patients with clinically suspected UEDVT. DESIGN: Diagnostic management study. (ClinicalTrials.gov: NCT01324037) SETTING: 16 hospitals in Europe and the United States. PATIENTS: 406 inpatients and outpatients with suspected UEDVT. MEASUREMENTS: The algorithm consisted of the sequential application of a clinical decision score, d-dimer testing, and ultrasonography. Patients were first categorized as likely or unlikely to have UEDVT; in those with an unlikely score and normal d-dimer levels, UEDVT was excluded. All other patients had (repeated) compression ultrasonography. The primary outcome was the 3-month incidence of symptomatic UEDVT and pulmonary embolism in patients with a normal diagnostic work-up. RESULTS: The algorithm was feasible and completed in 390 of the 406 patients (96%). In 87 patients (21%), an unlikely score combined with normal d-dimer levels excluded UEDVT. Superficial venous thrombosis and UEDVT were diagnosed in 54 (13%) and 103 (25%) patients, respectively. All 249 patients with a normal diagnostic work-up, including those with protocol violations (n = 16), were followed for 3 months. One patient developed UEDVT during follow-up, for an overall failure rate of 0.4% (95% CI, 0.0% to 2.2%). LIMITATIONS: This study was not powered to show the safety of the substrategies. d-Dimer testing was done locally. CONCLUSION: The combination of a clinical decision score, d-dimer testing, and ultrasonography can safely and effectively exclude UEDVT. If confirmed by other studies, this algorithm has potential as a standard approach to suspected UEDVT. PRIMARY FUNDING SOURCE: None.

A randomized study on 1-week versus 4-week prophylaxis for venous thromboembolism after laparoscopic surgery for colorectal cancer.

OBJECTIVE: To compare the efficacy and safety of antithrombotic prophylaxis given for 1 week or 4 weeks in patients undergoing laparoscopic surgery for colorectal cancer. BACKGROUND: Extending antithrombotic prophylaxis beyond 1 week reduces the incidence of venous thromboembolism (VTE) after open abdominal surgery for cancer. METHODS: In consecutive patients who underwent laparoscopic surgery for colorectal cancer, complete compression ultrasonography of the lower limbs was performed after 8 ± 2 days of antithrombotic prophylaxis. Patients with no evidence of VTE were randomized to short (heparin withdrawal) or to extended (heparin continued for 3 additional weeks) prophylaxis. Complete compression ultrasonography was repeated at day 28 ± 2 after surgery by investigators blinded to treatment allocation. The primary outcome of the study was the composite of symptomatic and ultrasonography-detected VTE at day 28 ± 2 after surgery. RESULTS: Overall, 301 patients were evaluated for inclusion in the study and 225 were randomized. VTE occurred in 11 of 113 patients randomized to short (9.7%) and in none of the 112 patients randomized to extended heparin prophylaxis (P = 0.001). The incidence of VTE at 3 months was 9.7% and 0.9% in patients randomized to short or to extended heparin prophylaxis, respectively (relative risk reduction: 91%, 95% confidence interval: 30%-99%; P = 0.005). The rate of bleeding was similar in the 2 treatment groups. Two patients died during the study period, 1 in each treatment group. CONCLUSIONS: After laparoscopic surgery for colorectal cancer, extended antithrombotic prophylaxis is safe and reduces the risk for VTE as compared with 1-week prophylaxis (NCT01589146).

Clinical evidence and rationale of mesoglycan to treat chronic venous disease and hemorrhoidal disease: a narrative review.

Chronic venous disease (CVD) and hemorrhoidal disease (HD) are among the most common vascular diseases in the world, with CVD affecting 22-41% of the population in Europe and HD having a point prevalence of 11-39%. The burden is substantial in terms of the effect of symptoms on patients' health-related quality of life (HRQoL) and direct/indirect medical costs. Treatment begins with lifestyle changes, compression in CVD and topical therapies in HD, and escalates as needed through oral therapies first and eventually to surgery for severe disease. CVD and HD share etiological features and pathological changes affecting the structure and function of the tissue extracellular matrix. Mesoglycan, a natural glycosaminoglycan (GAG) preparation composed primarily of heparan sulfate and dermatan sulfate, has been demonstrated to positively impact the underlying causes of CVD and HD, regenerating the glycocalyx and restoring endothelial function, in addition to having antithrombotic, profibrinolytic, anti-inflammatory, antiedema and wound-healing effects. In clinical trials, oral mesoglycan reduced the severity of CVD signs and symptoms, improved HRQoL, and accelerated ulcer healing. In patients with HD, mesoglycan significantly reduced the severity of signs and symptoms and the risk of rectal bleeding. In patients undergoing excisional hemorrhoidectomy, adding mesoglycan to standard postoperative care reduced pain, improved HRQoL, reduced incidence of thrombosis, and facilitated an earlier return to normal activities/work, compared with standard postoperative care alone. The clinical effects of mesoglycan in patients with CVD or HD are consistent with the agent's known mechanisms of action.

Editorial on the Special Issue "The New Frontier of Venous Thromboembolism".

In recent years, great efforts have been made to improve decision making in caring for patients of venous thromboembolism (VTE) [...].

Editorial Comment on the Special Issue Discussing COVID-19 and Thrombosis, Second Edition.

The recent SARS-CoV-2 pandemic is ending after over three years, and the efforts of physicians in the daily clinical management of infection in inpatients and outpatients and vaccination campaigns allowed to medical experts to understand all possible scientific aspects of COVID-19 [...].

Corrigendum: Diagnostic and therapeutic management of the thoracic outlet syndrome. Review of the literature and report of an Italian experience.

[This corrects the article DOI: 10.3389/fcvm.2022.802183.].

Delphi case: Sharing of clinical experiences for improvement in the treatment of chronic venous disease.

Chronic venous disease (CVD) is a common condition with major health consequences that is associated with poor long-term prognosis, significant socioeconomic impact, disabling symptoms, and reduced quality of life. To provide a novel evidence-based approach in the management of CVD, a consensus process ("Delphi Case") following a first Delphi Consensus was conceived. With a real-life fashion analysis, a steering committee formed by 3 expert leaders on chronic venous disease drove a panel of 77 expert Italian angiologists/vascular surgeons along a collegial discussion, integrating data coming from the guidelines recommendations of different Vascular Scientific Societies with the consensus agreement statements gathered from the first Delphi Consensus, and with data coming from the discussion of few statements in which there was disagreement. From July 15 to October 16, 2020, demographic, anamnestic, objective, and therapeutic data coming from a total of 2,275 patients were collected by the experts panel using a predefined case report form. The results of this second consensus provided a real-life picture of CVD management in the Italian population and clearly showed that a tailored therapeutic approach together with an appropriate lifestyle (e.g., diet, physical activity, weight loss) must be considered as the milestones for the CVD-related signs and symptoms clinical improvement in daily clinical practice. An evaluation of the adherence and of the efficacy of the prescribed pharmacological and compressive treatment in a medium-long term follow-up of the study population has been planned as the last step of this course and will be object of a future final publication.

Special Issue "COVID-19 and Thrombosis".

Since the pandemic began, an association among COVID-19 and venous thromboembolism has been reported, in particular for inpatients [...].

Correction: Di Micco et al. Clinical Differences between COVID-19 and a COVID-like Syndrome. J. Clin. Med. 2021, 10, 2519.

Incorrect Affiliation [...].

Risk Factors of Venous Thromboembolism in Noncritically Ill Patients Hospitalized for Acute COVID-19 Pneumonia Receiving Prophylactic-Dose Anticoagulation.

Background: Therapeutic/intermediate-dose heparin reduces the risk of thromboembolic events but increases the risk of major bleeding in patients hospitalized for acute COVID-19 pneumonia. Objectives: To prospectively assess the incidence of objectively proven venous thromboembolism (VTE) and identify predisposing risk factors in a cohort of hospitalized patients with acute COVID-19 pneumonia undergoing prophylactic-dose heparin. Patients and methods: All consecutive patients admitted for acute COVID-19 pneumonia to the General Internal Medicine Unit of Padova University Hospital, Italy between November 2020 and April 2021, and undergoing prophylactic-dose heparin, were enrolled. Demographic and clinical characteristics and laboratory and radiological findings were recorded on admission. Cases were patients who developed VTE during their hospital stay. Univariable and multivariable logistic regression analyses were used to ascertain the risk factors associated with developing in-hospital VTE. Results: 208 patients (median age: 77 years; M/F 98/110) were included; 37 (18%) developed in-hospital VTE during a median follow-up of 10 days (IQR, 4−18). VTE patients were significantly younger (p = 0.004), more obese (p = 0.002), and had a lower Padua prediction score (p < 0.03) and reduced PaO2/FIO2 ratio (p < 0.03) vs. controls. Radiological findings of bilateral pulmonary infiltrates were significantly more frequent in VTE patients than controls (p = 0.003). Multivariable regression showed that obesity (1.75, 95% CI 1.02−3.36; p = 0.04) and bilateral pulmonary infiltrates on X-rays (2.39, 95% CI 1.22−5.69; p = 0.04) were correlated with increased risk of in-hospital VTE. Conclusions: Obesity and bilateral pulmonary infiltrates on imaging may help clinicians to identify patients admitted to medical wards for acute COVID-19 pneumonia at risk of developing VTE despite prophylactic-dose heparin. Further studies are needed to evaluate whether the administration of therapeutic/intermediate-dose heparin may help prevent VTE episodes without further increasing the bleeding risk.

Rivaroxaban treatment for six weeks versus three months in patients with symptomatic isolated distal deep vein thrombosis: randomised controlled trial.

OBJECTIVE: To compare two different treatment durations of rivaroxaban in patients with symptomatic isolated distal deep vein thrombosis (DVT). DESIGN: Randomised, double blind, placebo controlled clinical trial. SETTING: 28 outpatient clinics specialising in venous thromboembolism. PARTICIPANTS: 402 adults (≥18 years) with symptomatic isolated distal DVT. INTERVENTIONS: After receiving standard dose rivaroxaban for six weeks, participants were randomly assigned to receive rivaroxaban 20 mg or placebo once daily for an additional six weeks. Follow-up was for 24 months from study inclusion. MAIN OUTCOMES MEASURES: The primary efficacy outcome was recurrent venous thromboembolism during follow-up after randomisation, defined as the composite of progression of isolated distal DVT, recurrent isolated distal DVT, proximal DVT, symptomatic pulmonary embolism, or fatal pulmonary embolism. The primary safety outcome was major bleeding after randomisation until two days from the last dose of rivaroxaban or placebo. An independent committee adjudicated the outcomes. RESULTS: 200 adults were randomised to receive additional rivaroxaban treatment and 202 to receive placebo. Isolated distal DVT was unprovoked in 81 (40%) and 86 (43%) patients, respectively. The primary efficacy outcome occurred in 23 (11%) patients in the rivaroxaban arm and 39 (19%) in the placebo arm (relative risk 0.59, 95% confidence interval 0.36 to 0.95; P=0.03, number needed to treat 13, 95% confidence interval 7 to 126). Recurrent isolated distal DVT occurred in 16 (8%) patients in the rivaroxaban arm and 31 (15%) in the placebo arm (P=0.02). Proximal DVT or pulmonary embolism occurred in seven (3%) patients in the rivaroxaban arm and eight (4%) in the placebo arm (P=0.80). No major bleeding events occurred. CONCLUSIONS: Rivaroxaban administered for six additional weeks in patients with isolated distal DVT who had an uneventful six week treatment course reduces the risk of recurrent venous thromboembolism, mainly recurrent isolated distal DVT, over a two year follow-up without increasing the risk of haemorrhage. TRIAL REGISTRATION: EudraCT 2016-000958-36; ClinicalTrials.gov NCT02722447.

Safety and Efficacy of Rivaroxaban as Extended-Phase Anticoagulation in Patients with Cancer and Venous Thromboembolism: A Preliminary Data Analysis from the Mac Project.

Extended-phase anticoagulation with direct oral Xa inhibitors (OAXI) is suggested in patients with cancer-associated venous thromboembolism (CAT). We report on patients enrolled in the MAC (Monitoring AntiCoagulants) Project, given rivaroxaban as extended-phase anticoagulation after CAT. The primary efficacy outcome was the incidence of symptomatic recurrent VTE; the primary safety outcomes were incidence of major and non-major clinically relevant bleeding, adverse events, and all-cause mortality. The mean patients' follow-up was 19 months (SD 16); 64/604 (11%) had CAT. Recurrent VTE occurred in 9.3% and in 8.1% of patients with and without CAT (OR 1.2, 95% CI 0.5 to 2.9; p = 0.6). Major bleeding occurred in 4.7% and in 2.6%, respectively (OR = 1.8, 95% CI 0.5 to 6.6, p = 0.4), and non-major clinically-relevant bleeding in 4.7% and in 4.1% (OR = 1.2, 95% CI 0.3 to 3.9, p = 0.7). The relative figures for fatal haemorrhage and all-cause death were 1.6% versus 0%, and 1.6% versus 0.4%. Rivaroxaban appears to be effective and safe as extended-phase anticoagulation in patients with CAT. The mean treatment period was 3-times the standard 6-month course.

Safety and Efficacy of Rivaroxaban for Extended-Phase Anticoagulation of Patients with Unprovoked or Recurrent Venous Thromboembolism: Real-Life Data from the MAC Project.

Venous thromboembolism (VTE) is a major cause of death in the world. After the acute-phase treatment, the optimal duration of anticoagulation is still debatable. The latest guidelines suggest maintaining long-term anticoagulation in patients with cancer-associated thrombosis (CAT) or with unprovoked VTE and a low bleeding risk. Methods: The MAC Project is an ongoing prospective-cohort, multi-center, observational study in Italy. The project aims to collect real-life clinical information in unselected patients given oral anticoagulants for VTE over a 5-year follow-up period. There were no exclusion criteria, except for life expectancy <6 months and refusal to sign the informed consent form or to attend the planned follow-up visit. All patients were followed-up prospectively with clinical controls scheduled at 3, 6, and 12 months after the index event, and then annually for up to 5 years. The primary efficacy and safety outcomes were symptomatic recurrent VTE and major bleeding. Results: We analyzed 450 consecutive patients treated with rivaroxaban and referred them to the MAC Project database for unprovoked or recurrent VTE. Of these, 267 (55%) were unprovoked VTE, and 377 (87%) were symptomatic. We followed up with the patients for a mean of 22 months (Q1 10.7; Q3 37.4 months). Recurrent VTE occurred in 12 patients on rivaroxaban treatment (IR 1.7 per 100 person-years). Males had more recurrence than women. During the follow-up period, we recorded 13 (2.9%) major bleeding, 12 (2.7%) clinically relevant non-major bleeding, 8 minor bleeding, and no fatal bleeding events. Overall, bleeding events occurred in 33 (7.3%) patients, most occurring within the first 2 years of treatment. In addition, we observed a statistically significant higher incidence of bleeding in patients with a baseline HAS-BLED score of 3 to 4 compared with those with a score of 0 to 2, with most events occurring during the first 3 months of treatment (RR 5.9). Discussion: Rivaroxaban appears to be safe and effective for the long-term treatment of patients with recurrent or unprovoked VTE. Our results match previously published data, and we are confident that the continuation of the follow-up for up to 5 years will confirm these outcomes.

Predictors of use of direct oral anticoagulants in patients with venous thromboembolism: Findings from the Registro Informatizado Enfermedad Tromboembólica registry.

Background: Current guidelines recommend the use of direct oral anticoagulants (DOACs) for patients with venous thromboembolism (VTE). However little is known about the use of DOACs in daily practice. Methods: We used the RIETE registry to identify predictors of use of DOACs for initial and/or long-term therapy of VTE based on patient-related factors, institution-related factors or over time. Results: Among 41,678 patients from March 2013 to September 2021, 12,286 (29%) used DOACs: for initial therapy 6,456; for long-term therapy 12,046. On multivariable analysis, independent predictors were: age < 65 years (odds ratio [OR]: 1.30; 95% CI: 1.23-1.38), body weight <50 kg (OR: 0.54; 95% CI: 0.45-0.65) or >120 kg (OR: 0.64; 95% CI: 0.53-0.77), initial VTE presentation as pulmonary embolism (OR: 1.18; 95% CI: 1.13-1.25), recent bleeding (OR: 0.53; 95% CI: 0.45-0.63), renal insufficiency (OR: 0.44; 95% CI: 0.38-0.51), liver cirrhosis (OR: 0.32; 95% CI: 0.20-0.52), thrombocytopenia (OR: 0.40; 95% CI: 0.34-0.49), atrial fibrillation (OR: 1.58; 95% CI: 1.42-1.75) and prior VTE (OR: 1.14; 95% CI: 1.06-1.22). The DOACs were more likely used in other European countries (OR: 8.97; 95% CI: 8.49-9.49), America (OR: 6.35; 95% CI: 5.67-7.11) or in other countries of the world (OR: 2.99; 95% CI: 2.70-3.31) than in Spain, and progressively increased from 2013-2015 to 2016-2018 (OR: 2.78; 95% CI: 2.62-2.95) and 2019-2021 (OR: 6.36; 95% CI: 5.95-6.80). Conclusion: In this large multinational VTE registry, variations were observed in the use of DOACs according to patient or country factors, and over time. The safety, costs, and influence of the DOACs on VTE-related outcomes in daily practice warrant further investigation.

Diagnostic and Therapeutic Management of the Thoracic Outlet Syndrome. Review of the Literature and Report of an Italian Experience.

The Thoracic Outlet Syndrome is a clinical potentially disabling condition characterized by a group of upper extremity signs and symptoms due to the compression of the neurovascular bundle passing through the thoracic outlet region. Because of the non-specific nature of signs and symptoms, to the lack of a consensus for the objective diagnosis, and to the wide range of etiologies, the actual figure is still a matter of debate among experts. We aimed to summarize the current evidence about the pathophysiology, the diagnosis and the treatment of the thoracic outlet syndrome, and to report a retrospective analysis on 324 patients followed for 5 years at the Padua University Hospital and at the Naples Fatebenefratelli Hospital in Italy, to verify the effectiveness of a specific rehabilitation program for the syndrome and to evaluate if physical therapy could relieve symptoms in these patients.

Benign outcome of objectively proven spontaneous recanalization of internal carotid artery occlusion.

OBJECTIVE: Spontaneous recanalization of intracranial internal carotid artery (ICA) occlusion is frequent in embolic strokes. Spontaneous recanalization of the extracranial portion of the ICA occlusion of atherosclerotic or embolic origin is only anecdotally reported, and data are lacking about its incidence, natural history, and outcome in long-term follow-up. METHODS: Consecutive patients with ICA occlusion were prospectively identified and followed-up to detect the incidence of a spontaneous recanalization. Patients with objectively confirmed recanalization were prospectively followed-up to observe their natural history and the onset of new cerebrovascular events. ICA occlusion and spontaneous recanalization were diagnosed by means of color-coded Doppler ultrasound imaging or selective contrast angiography, or both. All patients were evaluated and treated for atherosclerotic risk factors. RESULTS: Spontaneous recanalization occurred in 16 of 696 patients (2.3%; 95% confidence interval, 1.3%-3.7%) with ICA occlusion after a mean interval of 38 months from the diagnosis of occlusion. Spontaneous recanalization was detected with color-coded Doppler ultrasound imaging and with selective contrast angiography, with a complete agreement of diagnostic findings. Two patients presented with symptomatic spontaneous recanalization. All patients with spontaneous recanalization were asymptomatic after a mean follow-up of 66.2 months. CONCLUSIONS: Spontaneous recanalization of previously occluded extracranial ICAs is more frequent than anticipated. Once it occurs, spontaneous recanalization seems to have a benign long-term course.