Raymond C. Shields

Efficacy and safety of intravenous phytonadione (vitamin K1) in patients on long-term oral anticoagulant therapy.

OBJECTIVES To determine the safety and efficacy of intravenously administered phytonadione (vitamin K1) in patients on routine oral warfarin anticoagulation. PATIENTS AND METHODS This retrospective cohort study comprised adults who were taking warfarin, were not bleeding, and received intravenous phytonadione anticoagulation therapy before a diagnostic or therapeutic procedure between September 1, 1994, and March 31, 1996. The main outcome measures were adverse reactions to intravenously administered phytonadione, prothrombin-international normalized ratio time values, the incidence of bleeding and thrombosis after the procedure, and the time between the procedure and return to anticoagulation after resumption of warfarin treatment. RESULTS Two (1.9%) of the 105 patients studied had suspected adverse reactions to intravenous phytonadione (dyspnea and chest tightness during infusion in both). For the 82 patients who underwent a procedure, the median time from phytonadione to procedure onset was 27 hours (range, 0.7-147 hours), which was significantly less for patients receiving an initial phytonadione dose of more than 1 mg (P=.009). None had thromboembolism after surgery, although 2 (2.4%) of the 82 patients had procedure-associated major bleeding. For the 60 patients resuming warfarin therapy after a procedure, the median time to return to therapeutic anticoagulation was 4.1 days (range, 0.8-31.7 days) and was unaffected by the phytonadione dosage. CONCLUSIONS Intravenous phytonadione appears to be safe and is effective for semiurgent correction of long-term oral anticoagulation therapy before surgery. In small doses, it does not prolong the patients time to return to therapeutic anticoagulation.

Lumbar artery pseudoaneurysm caused by a Gunther Tulip inferior vena cava filter.

Inferior vena cava (IVC) filters are widely used to decrease the risk of pulmonary embolism in patients with contraindications to anticoagulation. Complications include local hematoma, access site deep venous thrombosis (DVT), filter migration and embolization, leg penetration through the IVC wall, IVC occlusion, and filter fracture with embolization. Other rare complications include leg penetration into adjacent organs including duodenum and ureter. Lumbar artery pseudoaneurysms are rare and may be spontaneous, iatrogenic, or traumatic. To date, there have been 3 case reports of lumbar artery pseudoaneurysms caused by IVC filters. We present an additional case of a lumbar artery pseudoaneurysm caused by a Gunther Tulip IVC filter treated successfully with selective embolization.

Medical Management of Carotid Stenosis

Stroke is a leading cause of morbidity and mortality in the developed world. Although the rates of stroke have decreased in North America, there are significant areas of risk stratification and management that can be improved. Hypertension is the most significant and perhaps most modifiable risk factor for stroke. Carotid atherosclerotic disease is associated with 15% of ischemic strokes. Although carotid endarterectomy (CEA) remains a recommendation for significant symptomatic carotid stenosis, controversy continues in the management of asymptomatic and recurrent carotid stenosis. Medical management options and effectiveness has significantly improved since the early CEA trials were published. Optimal medical management now must incorporate aggressive risk factor reduction measures, particularly with antihyperlipidemic therapy. Improved understanding of the natural history of carotid atherosclerosis is necessary to improve the application of management strategies.

Pediatric median arcuate ligament syndrome: first report of familial pattern and transperitoneal laparoscopic release.

Median arcuate ligament syndrome (MALS) is a rare disorder resulting from luminal narrowing of the celiac artery by the insertion of the diaphragmatic muscle fibers. Surgical management entails division of the median arcuate ligament with or without celiac artery reconstruction. We are presenting an interesting case of a 16-year-old girl with postprandial abdominal pain and weight loss. Her mother also had MALS treated via open celiotomy with complete median arcuate ligament division and patch angioplasty of the celiac artery owing to persistent stenosis at our institution. After a diagnosis of MALS was confirmed in our patient, a transperitoneal laparoscopic release of the median arcuate ligament with skeletonization of the celiac artery and branch vessels was performed. The postoperative course was uneventful, and she was dismissed on postoperative day 2. She remains asymptomatic at 12-months follow-up. This represents the first report of a transperitoneal laparoscopic approach to MALS in an adolescent and the first report of a familial/generational component to MALS.

Polycythemia Vera A Case Report and Discussion on Pathogenic Mechanisms of Increased Thrombosis

Polycythemia vera is a myeloproliferative disorder characterized by increased red cell mass and frequently complicated by venous and arterial thrombosis. The mechanism underlying the increased incidence of thrombotic events remains illusive. Presented in this report are a case of a 77-year-old man diagnosed with polycythemia vera and a review of the current literature on the mechanisms underlying the increased incidence of thrombotic events in polycythemia vera.

Removal of floating inferior vena cava thrombus with the AngioVac device

A 35-year-old female with a heterozygous mutation for factor V Leiden, antiphospholipid syndrome, and systemic lupus erythematosus on enoxaparin monotherapy presented with a chronic (>3 months old) 10-cm long floating thrombus attached to the cephalic end of an inferior vena cava (IVC) filter. A computed tomography angiogram showed the IVC thrombus extending cephalad from an infrarenal IVC filter to the hepatic venous confluence superiorly (Panel A: large arrow – IVC filter; small arrow – thrombus). She had a history of multiple prior arterial and venous thromboemboli and previously required pulmonary artery thromboendarterectomy for chronic pulmonary emboli (PE) with pulmonary hypertension. A Gunther Tulip IVC filter (Cook Medical Inc., Bloomington, IN, USA) had been placed in 2002. She was asymptomatic with no associated intrafilter or deep venous thrombus caudal to the filter. Transesophageal echocardiogram (TEE) demonstrated a large mobile thrombus within the inferior vena cava near the hepatic vein (Panel B: arrow). The lupus anticoagulant was persistently positive by both the dilute Russell viper venom time (dRVVT) assay and platelet neutralization procedure (PNP) using the activated partial thromboplastin time (aPTT) assay platform. Heparin platelet factor 4 testing for heparin-induced thrombocytopenia was negative on two occasions (December 2010 and April 2014). Owing to the risk of embolization, a minimally invasive approach was pursued. After right internal jugular (IJ) and femoral venous access was obtained, an AngioVac cannula (Angiodynamics, Latham, NY, USA) was inserted through the IJ and advanced to the thrombus with TEE guidance (Panel C: narrow arrow – AngioVac; wide arrow – thrombus). To assist with thrombus extraction, the thrombus was amputated at its origin on the IVC filter with an Amplatz GooseNeck snare (Covidien, Plymouth, MN, USA). The thrombus was then removed through the AngioVac device, with solid material observed in the bypass filters (Panel D). Completion studies demonstrated no residual thrombus. The patient tolerated the procedure well and was reinitiated on anticoagulation immediately postoperatively. Images in Vascular Medicine

Reproducibility of aortic pulsatility measurements from ECG-gated abdominal CTA in patients with abdominal aortic aneurysms

Purpose: ECG-gated abdominal CT angiography with reconstruction of multiple, temporally overlapping CT angiography datasets has been proposed for measuring aortic pulsatility. The purpose of this work is to develop algorithms to segment the aorta from surrounding structures from CTA datasets across cardiac phases, calculate registered centerlines and measurements of regional aortic pulsatility in patients with AAA, and to assess the reproducibility of these measurements. Methods: ECG-gated CTA was performed with a temporal resolution of 165 ms, reconstructed to 1 mm slices ranging at 14 cardiac phase points. Data sets were obtained from 17 patients on which two such scans were performed 6 to 12 months apart. Automated segmentation, centerline generation, and registration of centerlines between phases was performed, followed by calculation of cross-sectional areas and regional and local pulsatility. Results: Pulsatility calculations for the supraceliac region were very reproducible between earlier and later scans of the same patient, with average differences less than 1% for pulsatility values ranging from 2% to 13%. Local radial pulsatilities were also reproducible to within ~1%. Aneurysm volume changes between scans can also be quantified. Conclusion: Automated segmentation, centerline generation, and registration of temporally resolved CTA datasets permit measurements of regional changes in cross-sectional area over the course of the cardiac cycle (i.e., regional aortic pulsatility). These measurements are reproducible between scans 6-12 months apart, with differences in aortic areas reflecting both aneurysm remodeling and changes in blood pressure. Regional pulsatilities ranged from 2 to 13% but were reproducible at the 1% level.

Automatic segmentation and co-registration of gated CT angiography datasets: measuring abdominal aortic pulsatility

Purpose: To develop robust, novel segmentation and co-registration software to analyze temporally overlapping CT angiography datasets, with an aim to permit automated measurement of regional aortic pulsatility in patients with abdominal aortic aneurysms. Methods: We perform retrospective gated CT angiography in patients with abdominal aortic aneurysms. Multiple, temporally overlapping, time-resolved CT angiography datasets are reconstructed over the cardiac cycle, with aortic segmentation performed using a priori anatomic assumptions for the aorta and heart. Visual quality assessment is performed following automatic segmentation with manual editing. Following subsequent centerline generation, centerlines are cross-registered across phases, with internal validation of co-registration performed by examining registration at the regions of greatest diameter change (i.e. when the second derivative is maximal). Results: We have performed gated CT angiography in 60 patients. Automatic seed placement is successful in 79% of datasets, requiring either no editing (70%) or minimal editing (less than 1 minute; 12%). Causes of error include segmentation into adjacent, high-attenuating, nonvascular tissues; small segmentation errors associated with calcified plaque; and segmentation of non-renal, small paralumbar arteries. Internal validation of cross-registration demonstrates appropriate registration in our patient population. In general, we observed that aortic pulsatility can vary along the course of the abdominal aorta. Pulsation can also vary within an aneurysm as well as between aneurysms, but the clinical significance of these findings remain unknown. Conclusions: Visualization of large vessel pulsatility is possible using ECG-gated CT angiography, partial scan reconstruction, automatic segmentation, centerline generation, and coregistration of temporally resolved datasets.

Hyperbaric Oxygen Therapy for Chronic Refractory Osteomyelitis of the Sternum

This report describes a 32-year-old woman with chronic refractory osteomyelitis of the sternum after multiple surgical procedures including a sternotomy with underlying colonic interposition that was successfully managed with hyperbaric oxygen therapy. The clinical course is reviewed, and the complexities of this diagnosis are then discussed, including a brief review of the mechanisms of management with hyperbaric oxygen therapy.

Direct oral anticoagulant medications in calciphylaxis

Recent studies suggest that calciphylaxis is a thrombotic condition in which arteriolar thrombosis leads to painful skin infarcts and consequent morbidity and mortality. Paradoxically, warfarin is implicated as a risk factor for calciphylaxis. Our objective is to report the use of oral direct thrombin and factor Xa inhibitors (termed direct oral anticoagulants [DOACs]) in patients with calciphylaxis.