CT venography for the diagnosis of postpartum venous thromboembolism: a prospective multi-center cohort study.

OBJECTIVES: To assess the role of CT venography (CTV) in the diagnosis of venous thromboembolism (VTE) during the postpartum period. MATERIALS AND METHODS: This multicenter prospective cohort study was conducted between April 2016 and April 2020 in 14 university hospitals. All women referred for CT pulmonary angiography (CTPA) for suspected pulmonary embolism (PE) within the first 6 weeks postpartum were eligible. All CTPAs were performed on multidetector CT machines with the usual parameters and followed by CTV of the abdomen, pelvis, and proximal lower limbs. On-site reports were compared to expert consensus reading, and the added value of CTV was assessed for both. RESULTS: The final study population consisted of 123 women. On-site CTPA reports mentioned PE in seven women (7/123, 5.7%), all confirmed following expert consensus reading, three involving proximal pulmonary arteries and four limited to distal arteries. Positive CTV was reported on-site in nine women, five of whom had negative and two indeterminate CTPAs, bringing the VTE detection rate to 11.4% (14/123) (95%CI: 6.4-18.4, p = 0.03). Expert consensus reading confirmed all positive on-site CTV results, but detected a periuterine vein thrombosis in an additional woman who had a negative CTPA, increasing the VTE detection rate to 12.2% (15/123) (95%CI: 7.0-19.3, p = 0.008). Follow-up at 3 months revealed no adverse events in this woman, who was left untreated. Median Dose-Length-Product was 117 mGy.cm for CTPA and 675 mGy.cm for CTPA + CTV. CONCLUSION: Performing CTV in women suspected of postpartum PE doubles the detection of venous thromboembolism, at the cost of increased radiation exposure. CLINICAL RELEVANCE STATEMENT: CTV can help in the decision-making process concerning curative anticoagulation in women with suspected postpartum PE, particularly those whose CTPA results are indeterminate or whose PE is limited to the subsegmental level. KEY POINTS: Postpartum women are at risk of pulmonary embolism, and CT pulmonary angiography can give equivocal results. CT venography (CTV) positivity increased the venous thromboembolism detection rate from 5.7 to 11.4%. CTV may help clinical decision-making, especially in women with indeterminate CTPA results or subsegmental emboli.

Low molecular weight fucoidan prevents neointimal hyperplasia in rabbit iliac artery in-stent restenosis model.

OBJECTIVE: Smooth muscle cell (SMC) proliferation within the intima is regulated by heparan sulfates. We studied a low molecular weight (LMW) fucoidan (sulfated polysaccharide from brown seaweed) on SMC proliferation in vitro and intimal hyperplasia in vivo. METHODS AND RESULTS: In vitro study revealed that LMW fucoidan reduces rabbit SMC proliferation and is internalized in SMC perinuclear vesicles. On rabbit iliac arteries perfused in vivo with fluorolabeled LMW fucoidan after angioplasty, the labeling was mainly located on sites of injury. Pharmacokinetic studies showed that LMW fucoidan exhibited in rats an elimination half-life of 56+/-25 minutes (n=8) after intravenous administration and a constant plasma rate for > or =6 hours after intramuscular administration. After stent implantation in their iliac arteries, rabbits were also treated with LMW fucoidan (5 mg/kg IM twice a day). Histomorphometric analysis at day 14 indicated that LMW fucoidan reduced intimal hyperplasia by 59% (1.79+/-0.4 versus 0.73+/-0.2 mm2, P<0.0001) and luminal cross-sectional area narrowing by 58% (0.38+/-0.08 versus 0.16+/-0.04, P<0.0001). Blood samples showed no anticoagulant activity due to LMW fucoidan. CONCLUSIONS: This natural polysaccharide with high affinity for SMCs and sustained plasma concentration markedly reduced intimal hyperplasia, suggesting its use for the prevention of human in-stent restenosis.

The optional VenaTech(™) Convertible (™) vena cava filter: experimental study in sheep.

PURPOSE: Retrieval of optional caval filters may be impaired by filter tilting, migration, fracture, or embedding in the IVC wall. The goal of this experimental study was to evaluate a new optional filter, convertible by unlocking and removing the filter head. METHODS: Forty-nine Pre-Alp sheep (average weight, 55 kg) were anesthetized. IVC was catheterized via the right femoral vein (n = 46) or via the internal jugular vein (n = 3) with a 12.9-F sheath. VenaTech(™) Convertible(™) IVC filters were inserted as either permanent filters (n = 14) or as filters to be converted. Conversion was immediately after deployment (n = 19) or delayed after 1, 3, or 6 months (n = 20). Filter delivery, deployment, and conversion with measurement of migration and tilting were evaluated by cavography. Incorporation of the filter's stabilizers and arms in the IVC wall was assessed by gross anatomy. RESULTS: Delivery system insertion, filter release, and immediate conversion were successful in all cases. Delayed conversion was completed in all but one sheep, due to insufficient snare tension. Complimentary balloon-catheter inflation was required in 12 of 20 delayed conversions to achieve filter opening. In all 49 sheep, no thrombosis, migration, or significant tilting occurred. Within 4 weeks of conversion, the filter's stabilizers and arms were incorporated into the IVC wall. Upon removal, the filter head was free of intimal growth. CONCLUSIONS: The VenaTech(™) Convertible(™) optional IVC filter was successfully implanted in all sheep with no migration or tilting. Conversion at various dates by filter head removal was feasible in all but one case.

The VenaTech LP permanent caval filter: effectiveness and safety in the prevention of pulmonary embolism--a European multicenter study.

PURPOSE: To evaluate (i) the appropriateness, safety, and patient outcomes after placement of the VenaTech LP caval filter and (ii) the success of filter insertion through various venous access routes. MATERIALS AND METHODS: An open multicenter prospective observational study was conducted in 12 European centers, including an initial part limited to four centers. Patients with common indications were eligible for inclusion after approval by an independent ethics committee. Over a 42-month period, 106 patients (46 men [43.4%], 60 women [56.6%]), 72.2 years +/- 13.3 of age (range, 37-97 y), with poor prognoses were included. Patients were examined 2-5 days after the procedure, then at 30 days +/- 5 and 90 days +/- 15 for clinical follow-up and filter assessment. Evaluation criteria were based on occurrence of pulmonary embolism (PE), adverse events, death, filter position, and caval patency. Data were available in 101 case report forms at days 2-5, in 75 at day 30 +/- 5, and in 60 at day 90 +/- 15. Two patients (1.9%) were lost to follow-up. RESULTS: The overall mortality rate was 20.8%. PE was present in 71 patients (67.0%). History of venous thromboembolic disease (VTED) was noted in 32 patients (30.2%), and recently diagnosed VTED was present in 101 patients (95.3%). Partial caval thrombosis was present before the procedure. Filter tilting of 10-45 degrees was seen in 3.9% of cases at days 2-5, 4.3% of cases at day 30 +/- 5, and 1.9% of cases at day 90 +/- 15. Follow-up evidenced neither clinical signs of PE nor significant device-related events. CONCLUSIONS: In a prospective patient cohort with a projected 3-month mortality rate of nearly 21.0% as a result of severe prognoses, the success of insertion via various venous access routes and the appropriateness and safety of the VenaTech LP caval filter were assessed. Findings at 90-day follow-up were free of symptomatic PE and device-related adverse effects.

Placement of the VenaTech LP caval filter in the elderly: feasibility and clinical benefits of insertion via the arm.

PURPOSE: To evaluate routine use of access sites in the arm for percutaneous caval filter placement (PCFP) in elderly patients. Neck arthritis, patient anxiety, access site thrombosis or fecal/urinary incontinence complicating jugular or femoral access may require alternative access sites in this population. METHODS: Access via the right arm was chosen for PCFP (VenaTech LP). The indication for PCFP was deep vein thrombosis, a history of pulmonary embolism, and a contraindication to anticoagulant therapy. Ultrasound-guided puncture was performed after diameter measurement of the arm veins (ØAV). The filter was inserted with standard imaging procedures. Procedural difficulty was graded and compared with ØAV and the angle from the arm vein to the superior vena cava (alphaAV/SVC). RESULTS: Over 2 years, 16 patients (14 women, 2 men) with an average age of 90 years (range 79-97 years) were included in the study. The average ØAV value of the basilic or brachial veins was 4.2 mm (range 3.0-5.1 mm). The minimal ØAV for successful access was determined after the first 15 patients. No hematoma occurred at the puncture sites. The average alphaAV/SVC value was 62 degrees (range 29 degrees -90 degrees ). Arm access was possible in 12 of 16 patients (75%) with ØAV >or= 3.5 mm and alphaAV/SVC >or= 29 degrees . Every procedure via the arm was graded "easy" by the operator, regardless of angulation values. Femoral access was used in one case due to the impossibility of traversing the heart (patient no. 2), and jugular access was used in 3 of 16 (19%) patients due to puncture failure (patient no. 4), small ØAV (3 mm) (patient no. 6), and stenosis of the distal right subclavian vein (patient no.16), respectively. CONCLUSION: PCFP via the arm can be routinely accomplished in patients older than 75 years, provided ØAV >or= 3.5 mm, and alphaAV/SVC >or= 29 degrees .

Histomorphometric evaluation of (198)Au endovascular brachytherapy in a renal artery restenosis model in rabbits.

OBJECTIVE: The main mid-term complication of percutaneous transluminal angioplasty of the renal artery is restenosis, which occurs in up to 50% of patients. Although no pharmacologic agent to date has been effective in preventing restenosis, both beta-ray emitters and gamma-ray emitters used in endovascular brachytherapy have been shown to reduce coronary restenosis. The objectives of this study were to evaluate the efficacy of (198)Au endovascular brachytherapy in preventing restenosis after percutaneous transluminal renal angioplasty and to determine the radiation dose to the operator. MATERIALS AND METHODS: Twenty-one New Zealand white rabbits (10 females and 11 males) weighing an average of 3.5 kg (range, 3.2-3.8 kg) who had been fed a normal diet underwent bilateral 33% overdilatation with deendothelialization of the renal arteries. After 7 weeks, the induced renal artery stenoses were treated by percutaneous transluminal renal angioplasty. The rabbits were randomly assigned to one of three groups before receiving endovascular 25-Gy irradiation at a radial 2.0-mm depth with a 0.5 x 15 mm (198)Au wire (106 MBq). The right renal artery was irradiated in group A; the left, in group B. The rabbits in group C randomly received a right- or left-sided dummy wire. Operator exposure to radiation was measured using thermoluminescent dosimeters and ionization chambers. The rabbits were sacrificed after 3 weeks. The aorta and renal arteries were perfusion-fixed. The renal arteries were removed for histologic and histomorphometric study. RESULTS: Forty-two renal arteries were cut into a series of 4- micro m-thick slices. Five arteries were thrombosed (two in the irradiated group and three in the control group, p > 0.05). In the patent arteries (n = 37), the average neointimal area was 0.068 mm(2) (range, 0.009-0.234 mm(2)) in 15 irradiated segments (315 slices total), whereas the average neointimal area was 0.135 mm(2) (range, 0.016-0.324 mm(2)) in 22 control segments (462 slices total) (analysis of variance, p < 0.009), showing a percentage area of restenosis of 10.4% in irradiated arteries and 43.4% in non-irradiated arteries (p < 0.0003). Radiation dose per procedure to the operator was 0.034 mSv in the index finger, 0.024 mSv in the wrist, and undectable in the body. CONCLUSION: Endovascular brachytherapy with (198)Au appears to inhibit early renal artery restenosis and exposes the operator to a safe level of radiation.