Knee Deep Vein Thrombosis Research Articles

‘Current trends in lower limb Doppler scanning in Ireland’

IntroductionThe clinical need to diagnose and treat above knee deep vein thrombosis (AKDVT) has long been established in literature and in practice. On the other hand, the need to diagnose and treat below knee deep vein thrombosis (BKDVT) continues to be debated in literature. This has resulted in variation in clinical guidelines and protocols nationwide. This research aims to establish if there is a standard practice in Irish ultrasound departments and if so, what that practice is and where sonographers are getting information to inform this. MethodsA questionnaire was designed using SurveyMonkey and distributed using online platforms. The questionnaire aimed to establish the experience of the sonographer, the types of exams performed, protocols/guidelines used as well as scenarios where the sonographer might deviate from protocol. ResultsThe study yielded 90 responses. The research found 49% of sites perform whole leg ultrasound routinely and 46% perform proximal ultrasound only. 41% of respondents said their protocols were based on clinical guidelines however, 22% of participants didn't know what these guidelines were. 49% of respondents were unaware of what treatment a patient would receive in cases where there is a high clinical suspicion of DVT, but the ultrasound is negative for DVT. ConclusionThe research has established a lack of consistency amongst sonographers and scanning practices with a fairly even split (49% of respondents perform whole leg ultrasound and 46% perform proximal only). Not only has the research identified a lack of standardised scanning approach nationwide, but inconsistencies are also seen in the guidelines that inform our department's protocols as well as inconspicuous terms used in radiology reporting and jargon in literature in relation to DVT. Implications for practice1. An inconsistency in practice has been established. Discussions are now needed to decide what guidelines should be implemented into Irish Ultrasound DVT protocols. 2. A national protocol for BKDVT would result in all patients in Ireland having access to the same standard of care. 3. Call for consensus on appropriate training for sonographers undertaking LLDs.

Incidence of symptomatic image-confirmed venous thromboembolism in outpatients managed in a hospital-led COVID-19 virtual ward.

Incidence of symptomatic image-confirmed venous thromboembolism in outpatients managed in a hospital-led COVID-19 virtual ward.

The Investigation and Management of Iliac Artery Endofibrosis: Lessons Learned from a Case Series

The objective was to summarise the lessons learned, and evolution in local practice over the last 7 years, in the investigation and surgical management of iliac artery endofibrosis. This was a retrospective case series. A case note review of consecutive patients investigated for suspected iliac artery endofibrosis by a single surgeon, over a 7 year period, was undertaken. Included were cases of first presentation and those who had previously undergone intervention. Some 63 patients were referred with suspected endofibrosis in the period 2011-17, four of whom had previously undergone surgery for the condition. After investigation of both limbs, 50 symptomatic limbs in 46 patients had a confirmed diagnosis; amongst those 46 patients, iliac artery endofibrosis was found in a further six asymptomatic, contralateral limbs. Individuals were diagnosed at a median age of 36 years (range 18-52 years) and typically presented with thigh claudication, foot numbness, and limb weakness on exercise. The median delay to diagnosis was 3 years (range 0-14 years). Complete external iliac artery occlusion was a feature in three cases. Overall, 27 limbs in 25 patients underwent operative repair; a further five limbs in four patients underwent operative repair at other centres internationally. There were three post-operative superficial wound infections (11%) and one below knee deep vein thrombosis (4%). Symptoms resolved in 23 cases (85%) with a median follow up of 2.1 years (range 65 days-5.7 years). Of the four limbs developing recurrent symptoms, two had undergone surgery for an occluded external iliac artery. Surgical repair in the medium term appears effective in resolving symptoms in most patients. Further investigation is needed to establish the durability of surgery and to delineate the natural history of the disease.

Patient with thrombophilia on anticoagulation with recurrent bleeding

Acquired haemophilia A is a rare life threatening bleeding disorder often presenting in older individuals with autoimmune disorders and malignancy, and postpartum state. This case study reports a patient on stable warfarin therapy for 10 years for an unprovoked above knee deep vein thrombosis with a known inherited homozygous factor V Leiden mutation. She had increasing bleeding thought to be warfarin related despite a therapeutic INR. Her coagulation profile was markedly abnormal with a disproportionately prolonged aPTT leading to further investigations confirming presence of an acquired factor VIII inhibitor. The patient was treated with high doses of steroids and rituximab. This case highlights the diagnostic pitfalls of a bleeding disorder in patients on warfarin therapy. The co-existence of acquired factor VIII inhibitor with homozygous factor V Leiden mutation poses unique treatment challenges.

GD01: Age-adjusted D-dimer and two-site compression point-of-care ultrasonography to rule out acute deep vein thrombosis

Introduction: Undiagnosed deep vein thrombosis (DVT) can lead to significant morbidity and mortality, including death from DVT-associated massive pulmonary embolism (PE). While several validated clinical prediction rules, blood test and imaging modalities exist to investigate a potential DVT, there is currently a lack of rapid, accessible and reliable methods to exclude the possibility of DVT without resorting to formal venous duplex scanning. Currently, the use in the ED of a validated clinical prediction rule combined to either a high-sensitivity D-dimer test or ultrasonography of the lower extremities has a poor predictive value, as 75-90% of patients suspected of DVT have a negative formal venous duplex scan. Compression bedside ultrasound has however recently been shown to be a safe, rapid and accurate method for the diagnosis of proximal DVT in the emergency department with a high sensitivity and specificity (combined sensitivity and specificity of 96.1% and 96.8%, respectively 1 ). Research question: In the present study, we will primarily assess whether two-site compression POCUS combined with a negative age-adjusted D-dimer test can accurately rule out DVT in ED patients regardless of the Wells criteria. Methods: This is a single-center, prospective, observational study carried out over one year in the Emergency Department of the Jewish General Hospital in Montreal, Quebec. We aim to enroll a convenience sample of 475 patients aged 18 years and older presenting to the ED with symptoms suggestive of a DVT. All enrolled patients will receive the standard of care required for a lower leg DVT presentation. After calculating Patients DVT risk using modified wells criteria, all patients will undergo POCUS for DVT followed by a D-dimer test. Based on their results, patients will either undergo formal duplex scanning, or will be discharged without further testing and receive a three-month phone follow-up. A true negative lower leg DVT will be defined as follows: (1) Negative follow-up phone questionnaire for patients who were sent home with no formal duplex venous scanning. (2) Negative formal duplex venous scanning for patients who were deemed likely to have lower leg DVT using the Wells score, with a negative D-dimer and POCUS. Age adjusted DVT was added to account for below knee DVT and avoid the need for patients to return for fellow up duplex study in 1 week. To estimate our technique’s sensitivity with a 4% margin of error with 95% confidence intervals, 92 confirmed DVT patients are needed. We expect to recruit a total 475 patients within one-year period at the JGH (95 DVT-positive patients and 380 DVT-negative patients). Impact: The use of compression bedside ultrasound with a negative age-adjusted D-dimer test to rule out DVT in the ED may accelerate the decision regarding patient disposition and significantly decrease the length of patient stay in the ED. In addition, it may help avoid unnecessary medical interventions and diagnostic tests, thus representing potential quality of care and cost-saving improvements as well.

Treatment of Isolated Below the Knee Deep Vein Thrombosis.

The natural history of isolated distal deep-vein thrombosis (IDDVT) is still uncertain, as well as the real clinical risks associated with the disease and the need for its diagnosis and treatment. While more and more IDDVTs are diagnosed in everyday clinical practice, their appropriate therapeutic management is, unfortunately, far from straightforward, and different recommendations on how patients with diagnosed IDDVT should be treated are present between expert professionals and even among international guidelines. The present article aims at briefly reviewing the issue of IDDVT therapy in general, particularly focusing on the different approaches to the treatment of the disease that have been suggested by recent guidelines, those that are currently adopted in clinical practice, and necessary future directions.

Subtrochanteric fracture non-unions with implant failure managed with the “Diamond” concept

BackgroundSubtrochanteric femoral non-unions in the setting of failed metalwork pose a challenging clinical problem. This study assessed the clinical outcome of patients treated according to the principles of the “Diamond” concept. MethodsBetween 2007 and 2011 all patients presented with a subtrochanteric atrophic aseptic non-union in the setting of metalwork failure (broken cephalomedullary reconstruction nail), and treated in a single tertiary referral unit were included to this study. The hypertrophic and the non-unions of pathologic fractures were excluded. The revision strategy was based on the “Diamond concept”; optimisation of the mechanical and the biological environment (implantation of growth factor (rhBMP-7), scaffold (RIA bone graft from contralateral femur) and concentrated mesenchymal stem cells (MSCs) harvested from the iliac crest). The minimum follow up was 26 months (16–48). ResultsFourteen patients met the inclusion criteria. A specific sequence of metalwork failure was noted with initial breakage of the distal locking screws followed by nail breakage at the lag screw level. The intraoperative examination of the removed nails revealed no gross structural damage indicative of inappropriate drilling at the time of the initial intramedullary nailing. Varus mal-alignment was present in the majority of the cases, with an average of 5.2 degrees (0–11). The average time to distal locking screw failure was 4.4 months (2–8.5) and nail failure was 6.5 months (4–10). The time to union after the revision surgery was 6.8 months (5–12). Complications included two deaths in elderly patients (due to unrelated causes), one pulmonary embolism, one myocardial infarction, one below the knee deep vein thrombosis and one blade plate failure that required further revision with double plating and grafting. ConclusionVarus mal-alignment must be avoided in the initial stabilisation of subtrochanteric fractures. Distal locking screw failure is predictive of future fracture non-union and nail breakage. In the absence of sepsis, a single stage procedure based on the “Diamond concept” that simultaneously optimizes the mechanical and biological environment is a successful method for managing complex subtrochanteric atrophic non-unions with failed metalwork.

Management of Isolated Calf Deep Vein Thrombosis: Is Treatment or Follow-Up Warranted

Objectives: There is no consensus regarding the management of isolated calf deep vein thrombosis (DVT). The aim of this study is to determine the proper management of isolated soleal, gastrocnemius, peroneal, and posterior tibial vein thrombosis in an outpatient population. We further aim to identify the results of management of below the knee DVT (BKDVT) with serial ultrasound imaging during a 30-day period vs anticoagulation. Methods: A retrospective review was conducted for records from January 2009 to December 2010 to identify patients with BKDVT. Trauma and inpatients were excluded from the study. Univariate and multivariate analyses were conducted as well as descriptive statistics of the data. Results: The study included 225 outpatients with isolated BKDVT. The cohort consisted of 41% male, predominantly Caucasian (88%) patients, who were a mean age of 64 years. Thrombus was present most frequently in the soleal vein (40.3%), followed by the gastrocnemius (25%), peroneal (23.5%), and the posterior tibial vein (11.3%). Anticoagulation was used to treat 30.7% of initially diagnosed BKDVTs. No statistically significant difference was noted in the rate of proximal propagation (P .27), or pulmonary embolism (P .70) with or without anticoagulation. A decrease of new thrombus in additional calf veins was seen with anticoagulation, 1.4% vs 14.1% without anticoagulation (P .01). Conclusions: In an outpatient population, serial ultrasound imaging is adequate management for BKDVT. There is no significant reduction in the rate of pulmonary embolism or proximal propagation for patients managed with anticoagulation vs serial duplex ultrasound imaging for isolated calf DVT. Owing to the formation of new thrombus, serial ultrasound imaging is warranted in an outpatient population.

Thromboembolic disease after total knee replacement: Experience of 5100 cases

The aim of the study was to quantify the incidence and timing of venous thromboembolic events (VTE) after total knee replacement (TKR). Data from 5100 consecutive TKRs performed over 10 years were prospectively collected. Cases were reviewed to identify thromboprophylaxis given, the diagnosis of VTE, treatment and adverse outcomes. There were 3 deaths (0.059%) from pulmonary embolism (PE). Of 123 VTEs identified, 55 had PE, 17 had above knee deep vein thrombosis (DVT), 28 had calf DVT and 14 had been incorrectly coded as VTE. There was considerable inappropriate treatment of calf DVT with resultant morbidity. There was an increase in diagnosis of PE between days 1 and 5 post surgery in the later part of the study, corresponding with increasing use of CT Pulmonary Angiography. Increasing diagnosis of PE may be due to detection of embolic debris from surgery due to greater vigilance rather than post-operative thromboembolism. Death from PE is rare following TKR.

Any questions: Postoperative deep vein thrombosis in patient with hormone replacement implant:

<i>A 49 year old woman developed an above knee deep vein thrombosis 10 days after a hysterectomy and hormone replacement treatment implant. Should the implant be removed and should she have anticoagulant treatment?</i>