Proximal Propagation Research Articles

Abstract 3088: Inferior Vena Cava (IVC) Thrombosis In A Patient With May Thurner Syndrome: A Rare Case Of Thrombotic Iliocaval Obstruction In Octogenarian Population.

Introduction: May Thurner Syndrome is an extrinsic compression of the left common iliac vein by the right common iliac artery against lumbar spine. It is a rare cause of the lower extremity deep venous thrombosis (DVT) in octogenarian population. There is barely any data to document the association of IVC thrombosis with May Thurner Syndrome. Blood stasis in the setting of venous compression can increase the risk for DVT distally but proximal DVT is rare in absence of any other risk factors of thromboembolism. Case Representation: We present a unique case of 86-year-old female who was incidentally diagnosed with IVC thrombosis, left common iliac vein thrombosis, and left sided May Thurner Syndrome that is never documented before in octogenarian population. She had IVC thrombosis extending to the left common iliac vein with extrinsic compression by the right common iliac artery. This case is unique as our patient did not have any risk factor for venous thrombosis other than May Thurner Syndrome. Conclusion: May Thurner Syndrome can increase the risk for DVT proximal propagation and IVC thrombosis. The management of IVC thrombosis and May Thurner Syndrome in octogenarian population needs to account for risk of pulmonary embolism and mortality when avoiding anticoagulation compared to risk of morbidity and mortality from bleeding with anticoagulation. The decision to further manage depends upon clinical features, risk factors and institutional resources.

Comparison of clinical outcomes among patients with isolated axial vs muscular calf vein thrombosis: A systematic review and meta-analysis

ObjectiveThrombi in the axial calf veins have quite different anatomical and physiological characteristics from that in the muscular calf veins, but their treatment was usually addressed in the same manner. We performed a meta-analysis of randomized and cohort studies to compare clinical outcomes among patients with isolated axial vs muscular calf deep vein thrombosis (DVT). MethodsRecurrent venous thromboembolism (VTE) was selected as the primary outcome. Resolution, proximal propagation of calf DVT, pulmonary embolism (PE), major bleeds, and clinically relevant non-major bleeds were separately analyzed as secondary outcomes. Data were pooled and compared with risk ratio (RR) and 95% confidence interval (CI). ResultsThirteen studies, consisting of 4889 patients, met the inclusion criteria and were included for analysis. A greater rate of recurrent VTE (FE model: RR, 1.23; 95% CI, 1.00-1.53; I2 = 29%), resolution (FE model: RR, 1.32; 95% CI, 1.01-1.72; I2 = 31%), proximal propagation (FE model: RR, 1.63; 95% CI, 1.10-2.41; I2 = 40%), and PE (FE model: RR, 2.79; 95% CI, 1.31-5.95; I2 = 0%) in the axial group compared with the muscular group. There was no difference in the pooled estimates for major bleeds (FE model: RR, 1.09; 95% CI, 0.61-1.95; I2 = 0%), and clinically relevant non-major bleeds (FE model: RR, 1.80; 95% CI, 0.93-3.48) in the axial and muscular arms. ConclusionsPatients with calf DVT limited to muscular veins might have a lower rate of recurrent VTE, resolution, proximal propagation, and PE vs those with axial calf vein involvement and exhibited similar safety outcomes.

TCTAP C-124 Touch-Me-Not: Proximal Propagation of Intramural Hematoma in Spontaneous Coronary Artery Dissection After Stenting

TCTAP C-124 Touch-Me-Not: Proximal Propagation of Intramural Hematoma in Spontaneous Coronary Artery Dissection After Stenting

Abstract 12977: Combined Coronary Stenting and Cutting Balloon Angioplasty in the Management of a Postpartum Spontaneous Coronary Artery Dissection

Introduction: Spontaneous coronary artery dissection (SCAD), whilst documented in the peripartum period, has limited data in regard to management with cardiac intervention. SCAD is typically managed conservatively; however, in cases of hemodynamic instability and persistent ischemia, cardiac intervention with percutaneous coronary intervention (PCI) or coronary artery bypass grafting can be considered. Case: We present the case of a 34-year-old G2P2 female, without significant past medical history, who initially presented with severe substernal chest pain, five days following a spontaneous vaginal delivery. Initial electrocardiogram revealed sinus bradycardia without ischemic changes. Troponin I was elevated to 0.22 and 0.24. Heparin infusion, Aspirin loading, and Metoprolol were initiated. Coronary catheterization was performed and revealed dissection of a large left circumflex artery dissecting distally into the first obtuse marginal (OM1). A drug eluting stent (DES) was placed to the OM1. However, this worsened the dissection hematoma, propagating distally to the second obtuse marginal (OM2), also treated with a DES. Cutting balloon angioplasty was performed on the proximal circumflex to fenestrate the dissection flap and prevent proximal propagation of the dissection. A third DES was placed to the proximal circumflex artery. The patient continued dual anti-platelet therapy (DAPT) for one year, without complication. Conclusions: SCAD, in a young postpartum female, is a rare and potentially catastrophic condition. We present a case of SCAD, managed with PCI. This case demonstrates both the risk of dissection propagation with coronary stenting, as well as potential risk mitigation with cutting balloon angioplasty. Figure 1. Coronary Catheterization with PCI. A , SCAD of Lateral Circumflex to OM1. B , Post-DES to OM1 with dissection propagation to OM2 . C , Post-DES to OM2. D , Post-Balloon angioplasty and DES to proximal lateral circumflex

Clinicopathological Characteristics of Cancer-Associated Venous Thromboembolism (CAT-VTE) from a Medicolegal Autopsy.

Objective: This study aimed to determine the clinicopathological characteristics of cancer-associated venous thromboembolism (CAT-VTE).Methods: A total of 47 cases of lethal pulmonary thromboembolism (PTE) with active cancer were investigated by autopsy records.Results: We studied 22 men and 25 women who were deceased at a mean age of 66±11 years. Nine (19%) patients had recently undergone cancer resection, 14 (30%) were undergoing clinical treatment for cancer, and 24 (51%) were autopsy-proven CAT-VTE. The colon (eight cases), lungs (seven cases), and ovaries (six cases) were frequent sites of a tumor. There were 29 (62%) cases of acute PTE and 18 (38%) of recurrent PTE. The embolic source was detected in 36/39 (92%) cases. Among them, 33 cases were leg deep vein thrombosis (DVT) and 31 were calf-type DVT. Three cases were isolated vena cava thrombi that were present near the tumor. Twenty-three (64%) cases were recurrent DVT.Conclusion: Most of the lethal CAT-VTE cases were induced by the same mechanism as non-CAT-VTE that originated from calf-type DVT with proximal propagation. However, the finding that patients had tumor-related vena cava thrombi suggested that prevention of CAT-VTE requires individualized treatment of patients according to their pathological condition. (This is secondary publication from Jpn J Phlebol 2020; 31(3): 123–129.)

Elephants evolved strategies reducing the biomechanical complexity of their trunk

The elephant proboscis (trunk), which functions as a muscular hydrostat with a virtually infinite number of degrees of freedom, is a spectacular organ for delicate to heavy object manipulation as well as social and sensory functions. Using high-resolution motion capture and functional morphology analyses, we show here that elephants evolved strategies that reduce the biomechanical complexity of their trunk. Indeed, our behavioral experiments with objects of various shapes, sizes, and weights indicate that (1) complex behaviors emerge from the combination of a finite set of basic movements; (2) curvature, torsion, and strain provide an appropriate kinematic representation, allowing us to extract motion primitives from the trunk trajectories; (3) transport of objects involves the proximal propagation of an inward curvature front initiated at the tip; (4) the trunk can also form pseudo-joints for point-to-point motion; and (5) the trunk tip velocity obeys a power law with its path curvature, similar to human hand drawing movements. We also reveal with unprecedented precision the functional anatomy of the African and Asian elephant trunks using medical imaging and macro-scale serial sectioning, thus drawing strong connections between motion primitives and muscular synergies. Our study is the first combined quantitative analysis of the mechanical performance, kinematic strategies, and functional morphology of the largest animal muscular hydrostat on Earth. It provides data for developing innovative "soft-robotic" manipulators devoid of articulations, replicating the high compliance, flexibility, and strength of the elephant trunk. VIDEO ABSTRACT.

Natural History of Isolated Below-Knee Vein Thrombosis in Patients with Spinal Cord Injury.

In the general population, serial imaging is recommended over anticoagulant therapy for below-knee deep vein thrombosis (BKDVT). However, no clinical trial in Asian patients with spinal cord injury and BKDVT has been performed. Therefore, we evaluated the natural course of BKDVT in patients with acute spinal cord injury. We retrospectively analyzed inpatients with spinal cord injury with BKDVT between 2016 and 2020. All patients underwent inpatient rehabilitation treatment and duplex ultrasonographic examination of both the lower extremities at follow-up. After screening 172 patients with acute spinal cord injury for deep vein thrombosis using duplex ultrasound, 27 patients with below-the-knee deep vein thrombosis were included in this study. The mean lower-extremity motor score (median, interquartile range) was 66.0, 54.0–74.5. Sixteen patients received a non-vitamin K antagonist oral anticoagulant (NOAC) for anticoagulation. None of the patients had proximal propagation according to the follow-up duplex ultrasonography. BKDVT disappearance was not significantly different between the NOAC treatment and non-treatment groups. Asian patients with spinal cord injury have a low incidence of venous thromboembolism and favorable natural history of BKDVT. We recommend serial imaging over anticoagulant therapy for BKDVT in these patients.

The outcome of isolated calf muscle vein thrombosis after open reduction and internal fixation for closed intra\u2010articular distal femur fractures: a prospective cohort study

BackgroundTo observe the outcome of isolated calf muscle vein thrombosis (ICMVT) undergoing open reduction and internal fixation (ORIF) for closed intra-articular distal femur fractures (DFFs) and to analyze related factors.MethodsThe study was designed as a prospective clinical cohort study at our hospital. From August 2018 to August 2020,a total of 140 patients with flesh ICMVT after ORIF for closed intra-articular DFFs were collected during hospitalization. After the administration of antithrombotic agents immediately after diagnosis, the location and prognosis of postoperative ICMVT were examined by Duplex ultrasonography (DUS) with a three-month follow-up. There were 29 males and 111 females with the average age of 70.16 ± 8.75 years old. Sonography was used to evaluate the resolution of muscular vein thrombosis at the time point of the third month postoperatively and the results were compared between the two time points. Multivariable analysis was performed to evaluate the relationship between the resolution of ICMVT three months postoperatively and risk factors including age, Body Mass Index (BMI), gender, thrombosis length (> 5 / ≤5 cm), thrombosis diameter(> 0.6/≤0.6 cm), and thrombosis-related biochemistry indices.ResultsThe postoperative ICMVTs was diagnosed at 5.47 ± 2.46 days after ORIF for closed intra-articular DFFs. At the follow up of 3 months,120 cases was tending to disappear with 88 cases(62.9 %) completely dissolved and 32 cases(22.9 %) partly dissolved. There existed 14 cases (10.0 %) without change on the size and 6 cases (4.2 %) with proximal propagation. Multivariate analysis revealed that thrombus diameter over 0.6 cm (odds ratio [OR], 8.900; 95 % confidence interval [CI]: 3.623–21.865), thrombus length over 5.0 cm (OR, 3.904; 95 % CI, 1.121–13.603), FIB over 3.0 g/L (OR, 3.627; 95 % CI, 1.356–9.689), and D-dimer over 1.0 mg/L (OR, 2.602; 95 % CI, 1.075–6.296) were four independent risk factors of non-completely dissolved ICMVTs.Conclusions85.8 % of ICMVT was tending to disappear at the third months after ORIF for closed intra-articular DFFs. Thrombus diameter, thrombus length, FIB, and D-dimer were four independent risk factors of non-completely dissolved ICMVTs. The Thrombus diameter has a significant effect on the natural course of ICMVTs, especially with diameter larger than 0.6 cm.

Descending thoracic aorta to bifemoral bypass grafting in Aortobiiliac occlusive disease

Introduction: The aim of this prospective study is to describe the clinical symptoms, investigation findings and surgical treatment of aortoiliac occlusive disease where abdominal approach not feasible or not possible for aortobifemoral bypass grafting. Method: From May 2013 to May 2019, ten patients were treated with descending thoracic aorto-bifemoral bypass for aortoiliac occlusive disease at Grant Medical College and JJ group of Hospitals, Mumbai (Maharashtra). Total 20 limbs were re-vascularized. Demographic data, co-morbid factors, per operative findings were noted. Indication for surgery is juxtarenal occlusion of the abdominal aorta, in most of the cases. In postoperative period, all patients were evaluated for appearance of distal pulsations, primary patency, warmness of foot, symptom relief, wound infection, healing of the ulcer, and complications. CT angiography was done in follow-up. Maximal followup of two years and minimum followup of one month was done after surgery. Results: No mortality. Mean duration of surgery was 2.5-5 h and mean blood loss was 250 - 400 mL. Major morbidity includes one graft occlusion. None of the patients developed proximal propagation of aortic thrombus. Ulcers showed healing. All patients had a good quality of life postoperatively. Postoperative angiography showed good re-vascularization. Conclusion: Majority of our patients are old age having juxtarenal aortic occlusion so we decided to use DTA as inflow for primary revascularization to avoid entering abdomen and renal injury. Some authors have recommended supraceliac aorta bypass surgery within the retroperitoneal space for juxtarenal aortic occlusive disease but is technically difficult and associated with morbidity. The major limitation to thoracic aorta bifemoral grafting technique is the morbidity rate associated with thoracotomy in a relatively high-risk vascular surgery population. Also, tunnelling in conventional DTA-to-femoral artery bypass is usually a “blind” procedure.For the cardiothoracic surgeon with experience, the use of descending thoracic aorta could be a very good alternative for infrarenal aortic occlusion or extra-anatomic aortoiliac bypass without any morbidity and mortality with good improvement in quality of life.

Pathophysiology of Venous Thromboembolism with Respect to the Anatomical Features of the Deep Veins of Lower Limbs: A Review

Here the pathophysiology of venous thromboembolism is reviewed with respect to the anatomical features of the deep veins of lower limbs. A thrombus is less likely to form in the thigh veins compared with that in the calf veins; however, clinical symptoms are more likely to appear in the thigh veins owing to vascular occlusion. When a patient is bedridden, thrombosis is more likely to occur in the intramuscular vein, which mainly depends on muscular pumping and the venous valve, rather than in the three crural branches, which mainly depends on the pulsation of the accompanying artery. Thrombi are prone to be generated in the soleal vein compared with those in the gastrocnemius vein because of the vein and muscle structures. A soleal vein thrombosis grows toward the proximal veins along the drainage veins. To prevent a sudden pulmonary thromboembolism-related death in bedridden patients, preventing soleal vein thrombus formation and observing the thrombus proximal propagation via the drainage veins are clinically important. When deep vein thrombosis occurs, avoiding embolization and sequela caused by the thrombus organization is necessary.

Anticoagulation in patients with isolated distal deep vein thrombosis: a meta‐analysis

Background The optimal management of patients with isolated distal deep vein thrombosis (IDDVT), concerning both the need for anticoagulation and its duration, is undefined. Objectives We performed a meta-analysis of randomized and cohort studies in patients with IDDVT to assess the clinical benefit of: (i) anticoagulation versus no anticoagulation; and (ii) anticoagulant treatment for 6weeks versus for >6weeks. Methods The primary outcome of this analysis was recurrent venous thromboembolism (proximal propagation, recurrence of deep vein thrombosis, and pulmonary embolism). Data were pooled and compared by the use of odds ratio (OR) and 95% confidence interval (CI). Results A reduction in the rate of recurrent venous thromboembolism was observed in patients who received anticoagulation relative to those who did not receive anticoagulation (either therapeutic or prophylactic) (20 studies, 2936 patients; OR0.50, 95%CI0.31-0.79), without an increase in the risk of major bleeding (OR0.64, 95%CI0.15-2.73). The rate of pulmonary embolism was lower in anticoagulant-treated patients than in controls (15 studies, 1997 patients; OR0.48, 95%CI0.25-0.91). A lower rate of recurrent venous thromboembolism was observed in patients who received >6weeks of anticoagulant therapy than in those who received 6weeks of anticoagulant therapy (four studies, 1136 patients; OR0.39, 95%CI0.17-0.90). Conclusions In patients with IDDVT, anticoagulation (both therapeutic and prophylactic) reduces the rate of recurrent venous thromboembolism and the incidence of pulmonary embolism as compared with no anticoagulation, without an increased risk of major bleeding. Anticoagulation for >6weeks should be preferred over shorter durations.

Gastrointestinal Bleeding During Anticoagulant Therapy for Deep Vein Thrombosis after Simultaneous Pancreas and Kidney Transplantation

A 46-year-old Japanese woman on dialysis for type 1 diabetes and chronic renal failure underwent simultaneous pancreas and kidney transplantation from a brain-dead donor. On postoperative day 3, ilio-femoral deep vein thrombosis on the side of pancreatic transplantation was diagnosed from swelling of the right leg, an increased D-dimer level, and imaging findings. Anticoagulant therapy was initiated to prevent proximal propagation of the thrombosis and pulmonary thromboembolism. However, gastrointestinal bleeding occurred, which was thought to be due to mucosal bleeding from the duodenal graft. Her anticoagulant therapy was adjusted and hemostasis was conducted, controlling the gastrointestinal bleeding without surgical intervention. Blood flow was maintained to both grafts and graft function was good. When gastrointestinal bleeding occurs during anticoagulant therapy for deep vein thrombosis after combined pancreas and kidney transplantation, bleeding can be controlled by adjusting anticoagulant therapy and other appropriate measures.

Pathophysiology of Venous Thromboembolism with Respect to the Anatomical Features of the Deep Veins of Lower Limbs: A Review.

Here the pathophysiology of venous thromboembolism is reviewed with respect to the anatomical features of the deep veins of lower limbs. A thrombus is less likely to form in the thigh veins compared with that in the calf veins; however, clinical symptoms are more likely to appear in the thigh veins owing to vascular occlusion. When a patient is bedridden, thrombosis is more likely to occur in the intramuscular vein, which mainly depends on muscular pumping and the venous valve, rather than in the three crural branches, which mainly depends on the pulsation of the accompanying artery. Thrombi are prone to be generated in the soleal vein compared with those in the gastrocnemius vein because of the vein and muscle structures. A soleal vein thrombosis grows toward the proximal veins along the drainage veins. To prevent a sudden pulmonary thromboembolism-related death in bedridden patients, preventing soleal vein thrombus formation and observing the thrombus proximal propagation via the drainage veins are clinically important. When deep vein thrombosis occurs, avoiding embolization and sequela caused by the thrombus organization is necessary.

Systematic review of the complications following isolated calf deep vein thrombosis.

A large number of studies have examined the potential complications of calf deep vein thrombosis (DVT). There is no consensus on when or how to treat patients to prevent these complications. This systematic review assessed the rate of proximal propagation, pulmonary embolism, major bleeding and recurrence in patients with isolated calf DVT. Database searches of MEDLINE, the Cochrane Library, Scopus, CINAHL and Web of Science were undertaken along with extensive cross-referencing. Two independent reviewers screened the papers using stringent inclusion and exclusion criteria. Included studies were graded on six methodological standards. Data on propagation, pulmonary embolism, recurrence and major bleeding were abstracted. A total of 4261 papers were found; 15 met the inclusion criteria, including five randomized clinical trials and ten prospective cohort studies. The propagation rate to the popliteal vein or above was around 9 per cent and the rate of pulmonary embolism was close to 1·5 per cent. No studies found anticoagulant therapy to reduce the rate of adverse outcomes. The literature on calf DVT is heterogeneous, limiting conclusions from data analysis. Adverse outcomes are infrequent and studies do not suggest that they are reduced by anticoagulation.

Clinical Significance of the Soleal Vein and Related Drainage Veins, in Calf Vein Thrombosis in Autopsy Cases with Massive Pulmonary Thromboembolism.

To clarify the histopathological characteristics of deep vein thrombosis (DVT) resulting in lethal pulmonary thromboembolism (PE). We investigated 100 autopsy cases of PE from limb DVT. The distribution and chronology of DVT in each deep venous segment were examined. Venous segments were classified into three groups: iliofemoral vein, popliteal vein and calf vein (CV). The CV was subdivided into two subgroups, drainage veins of the soleal vein (SV) and non drainage veins of SV. Eighty-nine patients had bilateral limb DVTs. CV was involved in all limbs with DVT with isolated calf DVTs were seen in 47% of patients. Fresh and organized thrombi were detected in 84% of patients. SV showed the highest incidence of DVTs in eight venous segments. The incidence of DVT gradually decreased according to the drainage route of the central SV. Proximal tips of fresh thrombi were mainly located in the popliteal vein and tibioperoneal trunk, occurring in these locations in 63% of limbs. SV is considered to be the primary site of DVT; the DVT then propagated to proximal veins through the drainage veins. Lethal thromboemboli would occur at proximal veins as a result of proximal propagation from calf DVTs.

Management and outcomes of axial isolated distal deep vein thrombosis at North Shore Hospital, New Zealand: a retrospective audit

It is standard of care to treat proximal vein deep vein thrombosis (DVT) for a minimum of 3 months. Conversely, management of isolated distal DVT (IDDVT) is controversial, with options including observation and repeat ultrasound scan within 1 week to detect and anticoagulate those with proximal propagation, or anticoagulation for periods of up to 3 months. The aim was to assess the rates of proximal propagation and venous thromboembolism (VTE) recurrence within 3 months of diagnosis of IDDVT, and to examine how the duration of treatment might influence this. Study patients were identified by retrospective audit of data from the North Shore Hospital VTE database. All patients presenting with established axial vein distal DVT from July 2007 to June 2012 were included. A 6-week treatment duration cut-off was used to separate the treatment arms (<6 weeks vs 6 weeks vs >6 weeks), and Fisher's exact or Pearson's Chi-squared tests were used to assess between-group comparisons. Five hundred and seven patients were included in the study, mean age 59.7 years; 53% female. There were three cases of proximal propagation, all occurring in those receiving <6 weeks treatment. There were six VTE recurrences, three in the <6 week and three in the ≥6 week treatment groups respectively. Malignancy was the only significant predictor of VTE recurrence (P = 0.001). A 6-week duration of anticoagulation appears to be an effective and safe treatment for isolated axial distal DVT, with low rates of VTE recurrence and proximal propagation.

The Anticoagulation of Calf Thrombosis (ACT) Project: Results From the Randomized Controlled External Pilot Trial

BACKGROUND:There is currently little evidence defining the clinical importance of detecting and treating isolated distal DVT (IDDVT). International guidelines vary regarding diagnostic and therapeutic advice. The potential benefits of anticoagulation are unquantified. We sought to evaluate the feasibility of a randomized controlled study within a modern framework and provide a primary outcome point estimate.METHODS:In this open-label, external pilot randomized controlled trial, consecutive, symptomatic, ambulatory patients with IDDVT were approached for inclusion. Participants were allocated to receive either therapeutic anticoagulation or conservative management. Patients underwent blinded color-duplex imaging at 7 and 21 days and follow-up at 3 months. Principal feasibility outcomes included recruitment rate and attrition. The principal clinical outcome was a composite including proximal propagation, pulmonary embolism, death attributable to VTE disease, or major bleeding. Analysis was by intention to treat.RESULTS:In total, 93 patients with IDDVT were screened, and 70 of those eligible (88.6%) were recruited. All patients but one were followed-up by direct contact after 90 days. Allocation crossover occurred in 15 patients (21.4%). The principal clinical outcome occurred in four of 35 of those conservatively treated (11.4%) and zero of 35 in the anticoagulated group (absolute risk reduction, 11.4%; 95% CI, −1.5 to 26.7,P= .11, number needed to treat of nine). There were no major bleeding episodes.CONCLUSIONS:We have established the feasibility of definitive study regarding the value of therapeutic anticoagulation in IDDVT and provide an approximate point estimate for serious complications with a contemporary conservative strategy.TRIAL REGISTRY:Current Controlled Trials; No.: ISRCTN75175695; URL:www.controlled-trials.com.

Outpatient Surveillance Protocol of Isolated Calf Deep-Vein Thrombosis

Objectives This study aims to compare the management of isolated soleal, gastrocnemius, peroneal, and posterior tibial vein thrombosis among outpatients with serial duplex ultrasound (DUS) over 30 days, versus anticoagulation. Methods After obtaining IRB approval, a retrospective chart review was conducted from January 2009 to December 2010. A total of 15, 877 lower extremity DUS were performed. Inpatients, trauma patients, and patients with thrombi in or proximal to the popliteal vein were excluded to focus exclusively on an unprovoked outpatient population. Univariate and multivariate analyses were conducted as well as descriptive statistics of the data. Results The cohort consists of one hundred sixty-eight (n = 168) outpatients with isolated calf deep vein thrombosis (ICDVT). Thrombus was most frequently identified in the soleal vein (45%) followed by the peroneal (39%), gastrocnemius (29%), and the posterior tibial vein (23%). Following diagnosis of ICDVT, thirty-eight patients (n = 38) received anticoagulation. The remaining cohort (n = 130) underwent surveillance with serial DUS at 3, 10, and 30 days. Eleven percent (11%) propagated to the popliteal vein or proximally during surveillance, versus 8% following anticoagulation. Among those that propagated proximally, 85% propagated within two weeks of initial diagnosis. Proximal propagation ( p = 0.8328), pulmonary embolism ( p = 0.0537), and development of new thrombus in additional calf veins ( p = 0.1471) did not differ among those treated with anticoagulation or serial DUS. Conclusions Serial DUS without anticoagulation is safe management of ICDVT in unprovoked ambulatory outpatients.

THE ANTICOAGULATION OF CALF THROMBOSIS (ACT) PROJECT: RESULTS FROM THE RANDOMISED CONTROLLED EXTERNAL PILOT TRIAL

Objectives & BackgroundThere is currently little evidence defining the clinical importance of detecting and treating isolated distal deep vein thrombosis (IDDVT). Contemporary international guidelines vary regarding diagnostic and therapeutic advice....

Age and Gender Effects on the Proximal Propagation of an Impulsive Force Along the Adult Human Upper Extremity

We tested the null hypotheses that neither age, gender nor muscle pre-cocontraction state affect the latencies of changes in upper extremity kinematics or elbow muscle activity following an impulsive force to the hand. Thirty-eight healthy young and older adult volunteers lay prone on an apparatus with shoulders flexed 75° and arms slightly flexed. The non-dominant hand was subjected to three trials of impulsive loading with arm muscles precontracted to 25, 50, or 75% of maximum pre-cocontraction levels. Limb kinematic data and upper extremity electromyographic (EMG) activity were acquired. The results showed that pre-cocontraction muscle level (p < 0.001) and gender (p < 0.05 for wrist and shoulder) affected joint displacement onset times and age affected EMG onset times (p < 0.05). The peak applied force (F1) occurred a mean (± SD) 27 (± 2) ms after impact. The latencies for the wrist, elbow, and shoulder displacements were 21 ± 3, 29 ± 5, and 34 ± 7 ms, respectively. Because the latencies for elbow flexion and lateral triceps EMG were 23 ± 5 and 84 ± 8 ms, respectively, muscle pre-activation rather than stretch reflexes prevent arm buckling under impulsive end loads.