Risk Factors For Thrombus Formation Research Articles

Oral Versus Parenteral Antibiotics for Osteoarticular Infections: You PICC.

A previously healthy 8-year-old girl presented to the emergency department with right hip pain and inability to bear weight on the right lower extremity. She had been afebrile at home, although was receiving ibuprofen for pain. Inflammatory markers were elevated, including a C-reactive protein (CRP) of 76.4 mg/L and an erythrocyte sedimentation rate of 40 mm per hour. A radiograph of the pelvis did not show any obvious joint effusion. Given the concern for septic hip, orthopedics was consulted and she was taken to the operating room for aspiration of her right hip joint. Aspiration showed cloudy yellow fluid with a white blood cell count >85 000. Orthopedics proceeded with incision and drainage and she was admitted for parenteral antibiotics. She was empirically started on cefazolin. The broth from her hip culture grew coagulase-negative Staphylococcus species, but the fluid culture was negative, and this was presumed to be a contaminant. The orthopedic and infectious disease teams made a joint decision to treat empirically with cefazolin for a total of 4 weeks for presumed septic hip. A peripherally inserted central catheter (PICC) was placed on hospital day 3 and she was discharged on hospital day 4. At the time of discharge, the patient had no hip pain, was afebrile, able to bear weight, and had a CRP of 8.8 mg/L. Four days after discharge, the patient presented to the emergency department with pain, erythema, and swelling above the site of her PICC line. A duplex ultrasound of the arm showed a deep vein thrombus. Her PICC line was removed and she was started on enoxaparin for 3 months. She was discharged on oral high-dose cephalexin. Total duration of treatment was 16 days; antibiotics were then discontinued based on a normal clinical examination and inflammatory markers. This case illustrates the harm that can …

Risk factors of thrombosis in a single method of microsurgical head and neck reconstruction: A multi-institutional study of 773 reconstructions with a free jejunal graft after total pharyngolaryngoesophagectomy for hypopharyngeal cancer.

The risk factors for thrombus formation in anastomotic vessels in free-flap head and neck reconstruction have been previously reported. However, the evidence is inconsistent. In total, 773 patients who underwent free jejunal graft reconstruction after pharyngolaryngoesophagectomy for hypopharyngeal cancer were enrolled at 12 institutions in Japan from 1995 to 2006. Both the resection area and the applied reconstruction method were constrained to overcome the limitations of previous studies. After the exclusion of recurrent cases, odds ratios (ORs) and 95% confidence intervals (CIs) for thrombosis were calculated in a multivariate logistic regression analysis. Postoperative anastomotic thrombosis developed in 23 patients (3.0%). In the multivariate analysis, the OR for thrombosis per 100-mL increase in blood loss was 1.24 (95% CI = 1.02-1.51), even after controlling for other risk factors. Our results show that the blood loss volume is an independent risk factor for thrombosis in free tissue grafts. © 2016 Wiley Periodicals, Inc. Head Neck 38: 1708-1716, 2016.

Risk Factors for Thrombus Formation on the Amplatzer Cardiac Plug After Left Atrial Appendage Occlusion

This study sought to identify risk factors for thrombus formation on the Amplatzer Cardiac Plug (ACP) (St. Jude Medical, St. Paul, Minnesota) after left atrial appendage occlusion. Left atrial appendage occlusion with the ACP aims to reduce the risk of embolic stroke and bleeding complications associated with vitamin K antagonists in patients with atrial fibrillation. We performed transesophageal echocardiography before discharge and after 3, 6, and 12months in 34 patients with atrial fibrillation undergoing ACP implantation and receiving dual antiplatelet therapy. Clinical, echocardiographic, and hemostaseological parameters were retrospectively analyzed to identify risk factors for thrombus formation. Three patients had thrombi before discharge, 3 more at the 3-month follow-up. Nodifferences were found in left atrial volume, left atrial appendage velocity, spontaneous echo contrast, transmitral gradient, or mitral regurgitation between patients without or with thrombi. CHADS2 (Congestion, Hypertension, Age, Diabetes, and Stroke) score (2.0 ± 1.1 vs. 4.3 ± 1.0), CHA2DS2-VASc (CHADS2 plus Vascular Disease and Sex Category) score (5.2 ± 1.3 vs. 6.8 ± 0.8), and pre-interventional platelet count (215.9 ± 63.9/nl vs. 282.5 ± 84.4/nl) were higher and ejection fraction (50.6 ± 11.4% vs. 39.7 ± 10.6%) lower in those with thrombi. Factor 2, factor 5, or methylenetetrahydrofolate reductase mutations and genetic variants associated with reduced clopidogrel activity were not more frequent in patients with thrombi. Transesophageal echocardiography identified 17.6% of patients with thrombus formation on the ACP despite dual antiplatelet therapy. CHADS2 and CHA2DS2-VASc scores, platelet count, and ejection fraction are risk factors for such thrombus formation.

Quantification of left atrial flow velocity distribution in atrial fibrillation using 4D flow MRI

Background Atrial fibrillation (AF) is an arrhythmia characterized by irregular electrical activity in the left atrium (LA). Thromboembolism is the most serious complication of AF, usually manifesting as stroke or systemic embolism (1). This is thought to be linked to the increased risk of thrombus formation in the LA due to a decrease in blood velocity (stasis) or flow abnormalities. A better appreciation of the underlying mechanisms and risk factors for thrombus formation in the individual patient are needed to improve risk stratification and therapy planning. Using 4D-flow MRI, time resolved blood velocity measurements can be made in patients with AF. The aim of this study was to compare LA velocity distributions in different groups of AF patients. We hypothesize that persistent AF results in more deranged LA flow patterns with reduced velocities which may be related to an increased risk of thrombus formation and thus stroke. Methods MRI data were acquired from 31 AF patients (mean age 63+/-10.5) from two groups (n=21 post-treatment, in sinus rhythm, n=10 in persistent AF). Each subject underwent gated 4D-Flow MRI on 1.5T and 3T MR systems (Siemens, Erlangen, Germany). After noise filtering, Maxwell, and eddy current correction, time resolved pathlines were emitted from planes placed manually over the pulmonary veins at the junction with the LA (Fig 1). The LA was segmented and the distribution of velocities was quantified by histogram analysis. Mean velocities were calculated for each subject group. In addition number of voxels with velocities greater than 0.2m/s was calculated. The selection of the velocity threshold was based on previous TEE results which found that systolic LA velocities less than 0.2m/s constitute a risk factor for stroke (2). Results Qualitative observation of the blood flow patterns in patients showed very different patterns between those subjects imaged in sinus rhythm and those in persistent AF. Fig 1 displays clear differences in blood flow at end systole (A,D), early diastole (B,E), and mid diastole (C,F) for a post-intervention AF patient in sinus rhythm and in persistent AF. The quantitative results from all subjects are summarized in fig 2. Patients with persistent AF had a mean blood flow of 0.14±0.03m/s, lower than AF patients in sinus rhythm (0.19±0.04m/s, p=0.006). 14% of the velocity values for patients in AF were greater than 0.2m/s, lower than patients in sinus (35%, p=0.004).

Case report: central venous catheterization via internal jugular vein with associated formation of perioperative venous thrombosis during surgery in the prone position

An unusual case of central venous catheter (CVC)-related thrombosis during supine surgery in the prone position is presented. A 76-year-old woman was scheduled for elective surgery to repair a broken lumbar instrument. A single-lumen CVC was inserted via the right internal jugular vein. Surgery was performed in the prone position, with the patient's face directed downward in the standard median position (i.e., no rotation), but with slight forward flexion at the neck. After the surgery, the external jugular vein was dilated, and a postoperative X-ray revealed an infiltrative shadow in the right thoracic cavity. Because cervical echography showed dilated cervical veins with a "moyamoya-type" echo, possibly indicating a thrombus, contrast-enhanced computed tomography was performed, revealing a venous thrombus in the right internal jugular vein. An internal jugular venous-velocity measurement suggested that her slightly flexed neck position and her prone position during surgery may have kinked the internal jugular vein, causing engorgement with venous blood. The presence of the internal jugular venous catheter may have created thrombogenic conditions. A patient's position during surgery can reduce deep venous-flow velocity, and venous blood may stagnate, contributing greatly to thrombogenicity. We should consider a patient's position during surgery as a risk factor for thrombus formation, and a careful preoperative evaluation should be made as to which route should be chosen for CVC.

Dual-Enhanced Cardiac CT for Detection of Left Atrial Appendage Thrombus in Patients With Stroke

A noninvasive method with high reliability and accuracy comparable to transesophageal echocardiography for identification of left atrial appendage thrombus would be of significant clinical value. The aim of this study was to assess the diagnostic performance of a dual-enhanced cardiac CT protocol for detection of left atrial appendage thrombi and for differentiation between thrombus and circulatory stasis in patients with stroke. We studied 83 consecutive patients with stroke (56 men and 27 women; mean age, 62.6 years) who had high risk factors for thrombus formation and had undergone both dual-source CT and transesophageal echocardiography within a 3-day period. CT was performed with prospective electrocardiographic gating, and scanning began 180 seconds after the test bolus. Among the 83 patients, a total of 13 thrombi combined with spontaneous echo contrast and 14 spontaneous echo contrasts were detected by transesophageal echocardiography. All 13 thrombi combined with spontaneous echo contrast were correctly diagnosed on CT. Using transesophageal echocardiography as the reference standard, the overall sensitivity and specificity of CT for the detection of thrombi and circulatory stasis in the left atrial appendage were 96% (95% CI, 78% to 99%), and 100% (95% CI, 92% to 100%), respectively. On CT, the mean left atrial appendage/ascending aorta Hounsfield unit ratios were significantly different between thrombus and circulatory stasis (0.15 Hounsfield unit versus 0.27 Hounsfield unit, P=0.001). The mean effective radiation dose was 3.11 mSv. Dual-enhanced cardiac CT with prospective electrocardiographic gating is a noninvasive and sensitive modality for detecting left atrial appendage thrombus with an acceptable radiation dose.

Resolution of cor pulmonale after medical management in a patient with cblC-type methylmalonic aciduria and homocystinuria: a case report

We describe a 3-year-old Hispanic male with cblC-type methylmalonic aciduria and homocystinuria who presented to the emergency department with progressive tachypnea, vomiting, and edema secondary to pulmonary embolism and cor pulmonale. With aggressive medical management, there was complete resolution of right heart failure and pulmonary hypertension after 3 months. Pulmonary embolism is rare in the pediatric population. Children with cblC-type methylmalonic aciduria and homocystinuria may be at increased risk for thrombus formation and pulmonary embolism due to chronic hyperhomocystinemia, a risk factor for thrombus formation in the adult population. Aspirin therapy may be indicated in children with inborn errors of metabolism that predispose to hyperhomocystinemia.

Abciximab for thrombolysis during intracranial aneurysm coiling

Thrombotic events are a common and severe complication of endovascular aneurysm treatment with significant impact on patients' outcome. This study evaluates risk factors for thrombus formation and assesses the efficacy and safety of abciximab for clot dissolution. All patients treated with abciximab during (41 patients) or shortly after (22 patients) intracranial aneurysm coil embolisation were retrieved from the institutional database (2000 to 2007, 1,250 patients). Sixty-three patients (mean age, 55.3 years, +/- 12.8) had received either intra-arterial or intravenous abciximab. Risk factors for clot formation were assessed and the angiographic and clinical outcome evaluated. No aneurysm rupture occurred during or after abciximab application. The intra-procedural rate of total recanalisation was 68.3%. Thromboembolic complications were frequently found in aneurysms of the Acom complex and of the basilar artery, whilst internal carotid artery aneurysms were underrepresented. Two patients died of treatment-related intracranial haemorrhages into preexisting cerebral infarcts. Two patients developed a symptomatic groin haematoma. Abciximab is efficacious and safe for thrombolysis during and after endovascular intracranial aneurysm treatment in the absence of preexisting ischaemic stroke.

Ischaemic stroke, factor V Leiden heterozygosity and left atrial thrombosis in sinus rhythm: a case report

We describe a 63-year-old man in sinus rhythm (SR) with an ischaemic stroke involving basal ganglia region on the right side. The patient was known to be heterozygous for factor V Leiden (FVL) mutation. On diagnostic work-up, no arterial sources of embolism were found. Transoesophageal echocardiography evidenced a left atrial (LA) thrombosis without relevant cardiopathies. LA thrombosis is generally associated to atrial fibrillation, atrial enlargement, mitral valve stenosis and left ventricular dysfunction, whereas mitral regurgitation is considered protective. To our knowledge, this is the first report of cardioembolic stroke related to a LA thrombosis in a patient in SR without risk factors for thrombus formation except for FVL heterozygosity.

Sonography for Deep Venous Thrombosis

Deep venous thrombosis (DVT) is a one of the most common problems facing the clinician in medicine today. It is often asymptomatic and goes undiagnosed with potentially fatal consequences. Ultrasound has become the "gold standard" in the diagnosis of deep venous thrombosis and with proper attention to technique sensitivity of this test is approximately 97%. An understanding of anatomy, pathophysiology, and risk factors is important. Thrombus formation usually begins beneath a valve leaflet below the knee. Approximately 40% will resolve spontaneously, 40% will become organized, and 20% will propagate. Whether or not a calf vein thrombus is identified, a repeat examination in 7 to 10 days is recommended in patients with risk factors or when deep venous thrombosis is suspected. The three main risk factors for thrombus formation are age greater than 75 years, previous history of deep venous thrombosis, and underlying malignancy. Other diagnostic studies include the contrast venogram, CT or MRI venogram, Tc99m Apcitide study, and the laboratory test D-Dimer. The D-Dimer study is being used more frequently as a screening test with 99% sensitivity in detecting thrombus, whether deep venous thrombosis or pulmonary embolism. However, specificity is only approximately 50% with many conditions leading to false-positive exams. Therefore, a negative examination is useful in avoiding other diagnostic studies, but a positive one may be misleading. Conditions that can lead to a false-positive examination include, but are not limited to diabetes, pregnancy, liver disease, heart conditions, recent surgery, and some gastrointestinal diseases. Like the sonogram, two negative D-Dimer studies a week apart exclude the diagnosis of deep venous thrombosis. Compression sonography with color Doppler remains the best overall test for deep venous thrombosis. It is easy to perform, less expensive than most "high tech" studies, can be performed as a portable examination, and is highly reliable when done properly.

Hyperhomocysteinemia and Left Internal Jugular Vein Thrombosis with Ménière's Symptom Complex

The author describes the case of a 68-year-old woman who experienced severe symptoms of Ménière's syndrome. Ultrasonography of the neck detected a clot in the left internal jugular vein. The patient was hospitalized and anticoagulated, and her symptoms soon resolved. The author speculates that the clot-induced hemodynamic changes led to venous insufficiency in the vein of the paravestibular canaliculus and ultimately caused the patient's symptoms. The blood work-up revealed that the patient had an elevated fasting homocysteine level, which is a known risk factor for thrombus formation.

Transesophageal Echocardiography in Patients With Focal Cerebral Ischemia of Unknown Cause

Identification of cardioembolic stroke is often limited by the difficulties involved in the detection of thrombi or the risk factors for thrombus formation. Patients in sinus rhythm with nondiagnostic transthoracic echocardiogram (TTE) and without carotid artery stenosis represent a subset in whom diagnostic recommendations are lacking. The aim of this study was to determine the value of transesophageal echocardiography (TEE) for diagnosis and therapy in this population. Thirty patients with the characteristics described above were studied prospectively with the use of blood analysis, TTE, TEE, and Holter monitoring (in patients with atrial thrombus). TTE was abnormal in 16 of 30 patients, but no embolic source was identified. TEE disclosed left atrial appendage thrombus in 3 of 30 patients, atrial septal aneurysm in 2 of 30 patients, patent foramen ovale in 7 of 30 patients, and aortic plaques in 19 of 30 patients. The Tee resulted in a change of therapy in 3 of the 30 patients studied. This study demonstrates that TEE is a helpful diagnostic tool in delineating the risk of cardioembolic stroke and demonstrates significant pathology even in a subset of patients deemed to be at low risk. This additional new information led to a substantial change in therapy in 3 of 30 patients.

Relation of thrombus in the left atrial appendage by transesophageal echocardiography to clinical risk factors for thrombus formation

Transesophageal echocardiography provides excellent visualization of the left atrial appendage (LAA). This study was conducted to determine whether specific clinical risk factors could predict the presence of LAA thrombus as demonstrated by transesophageal echocardiography. The most recent 860 transesophageal echocardiographic studies performed at our institution were retrospectively reviewed. The LAA was adequately visualized in 778 patients (90%). For each study, the presence or absence of 5 specific clinical risk factors (mitral stenosis, severe left ventricular dysfunction, left atrial dilatation, atrial fibrillation, or a prosthetic mitral valve) and the presence or absence of LAA thrombi were assessed. One or more clinical risk factors were present in 149 patients, whereas no defined risk factors were noted in 629. Left atrial appendage thrombi were found in 20 of 149 patients with versus 6 of 629 patients without a clinical risk factor (13% vs 1%, p = 0.0001). By logistic regression analysis, mitral stenosis, severe left ventricular dysfunction, and left atrial dilatation were independent risk factors for LAA thrombus formation. Neither atrial fibrillation nor the presence of a mitral prosthetic valve achieved statistical significance as independent risk factors for LAA thrombus. Thus, LAA thrombi occur most often in patients with risk factors for thrombus formation that can be determined by clinical evaluation and transthoracic echocardiography. Transesophageal echocardiography rarely identifies LAA thrombi in patients without such clinical risk factors.

Multivariate analysis of risk factors for thrombus formation in University of Tokyo ventricular assist device

Of 77 University of Tokyo ventricular assist devices used in a total of 70 patients at 21 institutions, 13 pumps were found to have macroscopic thrombus formations. Because 19 devices that were used for less than 24 hours showed no thrombus deposition, they were considered not to have been sufficiently exposed to the thrombogenic environment for macroscopic thrombus deposition and were removed from the subsequent multivariate study. A total of eight potential risk factors were assessed in relation to thrombosis. Prevalences of thrombus formation were compared between two groups with or without each of the risk factors. In a univariate analysis, the following categoric variables were demonstrated to be significantly associated with complications, in descending order of significance: use of gabexate mesilate (protease inhibitor) as an anticoagulant (p = 0.005), normal platelet count (p = 0.010), duration of support (p = 0.038), leukocytosis (p = 0.042), and minimum pumping flow (p = 0.042). Use of heparin and the consequent increase in activated clotting time showed no relationship. Multivariate discriminant analysis, which was done to identify risk factors rejecting cross correlation between each variable, demonstrated platelet count (p = 0.006), use of gabexate mesilate (p = 0.007), and minimum flow (p = 0.008) to have significant and independent risks. These results indicate the importance of maintaining pumping flow above a certain minimum level, addition of antiplatelet drugs to the antithrombogenic regimen, and nonuse of gabexate mesitate.

Damage to cytoplasmic membranes in patients with acute myocardial infarction

The dependence of damage to the outer cell membranes in patients with acute myocardial infarction on the characteristics of the fractional distribution of cholesterol was studied. Determination of 5-nucleotidase activity is an objective criterion for assessing damage to the outer cell membranes, which can be considered a risk factor for thrombus formation and progression of coronary heart disease.