Hemorrhagic complications of anticoagulant treatment

A recurrent neural network model predicts activated partial thromboplastin time after treatment with heparin: a retrospective study (Preprint)

Background

Anticoagulation therapy with heparin is a frequent treatment in intensive care units and is monitored by activated partial thromboplastin clotting time (aPTT). It has been demonstrated that reaching an established anticoagulation target within 24 hours is associated with favorable outcomes. However, patients respond to heparin differently and reaching the anticoagulation target can be challenging. Machine learning algorithms may potentially support clinicians with improved dosing recommendations.

Objective

This study evaluates a range of machine learning algorithms on their capability of predicting the patients’ response to heparin treatment. In this analysis, we apply, for the first time, a model that considers time series.

Methods

We extracted patient demographics, laboratory values, dialysis and extracorporeal membrane oxygenation treatments, and scores from the hospital information system. We predicted the numerical values of aPTT laboratory values 24 hours after continuous heparin infusion and evaluated 7 different machine learning models. The best-performing model was compared to recently published models on a classification task. We considered all data before and within the first 12 hours of continuous heparin infusion as features and predicted the aPTT value after 24 hours.

Results

The distribution of aPTT in our cohort of 5926 hospital admissions was highly skewed. Most patients showed aPTT values below 75 s, while some outliers showed much higher aPTT values. A recurrent neural network that consumes a time series of features showed the highest performance on the test set.

Conclusions

A recurrent neural network that uses time series of features instead of only static and aggregated features showed the highest performance in predicting aPTT after heparin treatment.

Antithrombotic Therapy in Spinal Surgery Does Not Impact Patient Safety–A Single Center Cohort Study

Objective

Antithrombotic therapy is common in older patients to avoid thromboembolic events. Careful planning is required, particularly in the perioperative environment. There are no clearly date guidelines on the best timing for interrupting the use of anticoagulation in the case of spinal surgery. This study evaluates early per procedural clinical outcomes in patients whose antithrombotic therapy was interrupted for spinal surgery.

Methods

This is a retrospective cohort study. All patients who underwent dorsal instrumentation from January 1, 2019 to December 31, 2020 were included. In group A, vitamin K antagonists (VKA) were suspended for 5 days and direct oral anticoagulants (DOAC) for 3 days. In group B, antiplatelet agents (APA) were paused for at least 7 days before surgery to prevent perioperative bleeding. Patients not taking anticoagulation medication were gathered into control group C. We analyzed demographic data, ASA status, blood loss, comorbidities, duration of surgery, blood transfusion, length of hospital stay, complications, thromboembolism, and 30 day in-hospital mortality. Multivariate analyses from the three groups were further analyzed and conducted.

Results

A total of 217 patients were operated and included. Twenty-eight patients taking VKA/DOAC (group A), 37 patients using APA (group B), and 152 patients without anticoagulation (group C) underwent spinal surgery. Those using anticoagulants were significantly older and often with multimorbidity, but did not differ significantly in procedural bleeding, time of surgery, length of hospital stay, complication rate, thromboembolism, or 30 day in-hospital mortality (p > 0.05).

Conclusion

Our data show that dorsal instrumentation safely took place in patients whose antithrombotic therapy was interrupted.

The Role of the Pharmacist in Developing Critical Pathways with Warfarin Therapy

The pharmacist can play a key role in the development of critical pathways for disease states with warfarin as a component of therapy. The pharmacist must be familiar with the complex therapeutic considerations involved with warfarin therapy. This paper will briefly review warfarin therapeutics and will discuss strategies for pharmacist involvement in development of critical pathways including warfarin therapy. Participation in the multidisciplinary planning of critical pathways provides an excellent opportunity to contribute to the efficient, safe, and cost-effective use of warfarin.

Perioperative Management of Antithrombotic Therapy in Common Otolaryngologic Surgical Procedures: State of the Art Review

OBJECTIVE

The perioperative management of patients undergoing otolaryngologic procedures is increasingly complicated by the use of newer antithrombotic agents. Furthermore, with advances in anesthesia and surgical technique, otolaryngologists are presented with the challenge of operating on patients with advanced comorbid diseases. The objective of this review is to provide evidence-based recommendations on perioperative antithrombotic management for common otolaryngologic procedures.

DATA SOURCES

PubMed/MEDLINE.

REVIEW METHODS

Selected literature on patient-specific thromboembolic risk, rate of bleeding complications in otolaryngologic procedures, and the interruption of antithrombotic therapy is reviewed and interpreted by expert opinion.

CONCLUSIONS

By stratifying patients into either low thromboembolic risk (≤ 5%) or high thromboembolic risk (> 5%) and interpreting this in the context of procedural bleed risk and potential clinical consequences in the event of a bleed, otolaryngologists can make evidence-based decisions to determine the appropriate perioperative management of antithrombotic therapy.

IMPLICATIONS FOR PRACTICE

When the perioperative management of antithrombotic therapy is being decided, 3 critical factors must be considered systematically: the patient's inherent thromboembolic risk, the risk and potential consequences of bleeding related to the procedure, and the timing of interruption of thromboembolic therapy.

Utilization of oral anticoagulation in a teaching hospital in Nigeria

Background:

Anticoagulation is an essential lifesaving management practice indicated for arterial, venous and intracardiac thromboembolism.

Aim:

This study was undertaken to examine the utilization of anticoagulation services in University of Nigeria Teaching Hospital, Enugu (UNTH) Nigeria.

Materials and Methods:

This retrospective study involved assessing data from folders of subjects on anticoagulation and monitoring in UNTH, Enugu. Patients’ profile, risk factors, diagnosis, indication for oral anticoagulation, anticoagulant used; target, monitoring, outcome and complications of anticoagulation were recorded.

Results:

A total of 26 patients over a period of 5 years were on anticoagulation and laboratory monitoring done in UNTH. The mean age of the patients was 53.4 years and more females than males were on anticoagulation and monitoring (F14:M12). The most common indications for anticoagulation include deep venous thrombosis/pulmonary embolism, congestive heart failure with atrial fibrillation and mitral valve disease with atrial fibrillation. Desired clinical outcome was achieved in eight patients 8/26 (30.8%). Minor bleeding was the only complication reported in three patients 3/26 (11.5%).

Conclusion:

The absence of diagnostic tools and anticoagulation monitoring clinics and the apprehension of adverse effects have combined to make this lifesaving treatment inaccessible to many patients in Nigeria.

Skin necrosis associated with thromboprophylaxis after total knee replacement

Thromboprophylaxis are routinely given to prevent venous thromboembolism (VTE) in patients after total hip and knee replacement surgeries. Low molecular weight heparin (LMWH) (fractioned heparin) is effective in the prevention and treatment of VTE. The predicable effect of LMWH has popularized it for routine clinical use. Although LMWH has lesser complication rate, compared to unfractioned heparin (UFH), sporadic clinical complication has been reported. We report a rare case of skin necrosis secondary to use of LMWH tinzaparin used for routine thromboprophylaxis after total knee replacement.

Does chronic warfarin cause increased blood loss and transfusion during lumbar spinal surgery?

BACKGROUND CONTEXT

The use of oral anticoagulation therapy such as warfarin is projected to increase significantly as the population ages and the prevalence of cardiovascular disease increases. Current recommendations state that warfarin be discontinued before surgery and the international normalized ratio (INR) normalized.

PURPOSE

To determine if stopping warfarin 7 days before surgery and correcting INR had any effect on intraoperative blood loss or the requirements for blood product transfusion.

STUDY DESIGN/SETTING

This was a retrospective cohort study in a high-volume tertiary care center.

PATIENT SAMPLE

Sample comprised 263 consecutive patients who underwent elective lumbar spinal surgery.

OUTCOME MEASURE

The outcome measures were intraoperative blood loss, intraoperative blood transfusion, postoperative blood transfusion, and the number of blood products transfused.

METHODS

The records of patients undergoing elective spinal surgery were analyzed for patient demographic data, comorbidities, coagulation panel laboratory findings, operative characteristics, blood loss, and blood transfusion requirements. These included patients undergoing full laminectomies with or without posterolateral fusion and instrumentation. Patients on warfarin were analyzed for the mean dosage of warfarin and underlying pathology that required anticoagulation. All patients on warfarin had their anticoagulation therapy stopped 7 days before surgery and their INR checked preoperatively to confirm normalization. Both univariate and multiple linear regression analyses were performed.

RESULTS

The patients on warfarin had a mean intraoperative blood loss of 839 mL compared with 441 mL for patients not on warfarin (p<.01). Multiple regression analysis determined that warfarin and number of spinal levels decompressed/fused/instrumented were predictors for increased blood loss (R(2)=0.37). Patients on warfarin also had increased postoperative blood transfusions (23.1% compared with 7.4%, p=.04). There was no significant difference between groups in terms of intraoperative blood transfusion or number of units transfused.

CONCLUSIONS

Patients on chronic anticoagulation therapy with warfarin who have their therapy stopped 7 days before surgery and have their INR normalized still demonstrated increased intraoperative blood loss and requirement for postoperative transfusion. Surgeons should be aware of the increased propensity of these patients to bleed despite adherence to protocols and should attempt to mitigate this risk.

Heparin-grafted dialysis membrane allows minimal systemic anticoagulation in regular hemodialysis patients: a prospective proof-of-concept study

This prospective, multicenter, proof-of-concept study aimed to evaluate the possibility to reduce the ordinary heparin dose and the systemic anti-Xa activity during hemodialysis (HD) sessions using a new heparin-grafted HD membrane. In 45 stable HD patients, the use of a heparin-grafted membrane with the ordinary heparin dose was followed by a stepwise weekly reduction of dose. Reduction was stopped when early signs of clotting (venous pressure, quality of rinse-back) occurred during two out of three weekly HD sessions. Heparin dose was decreased for 67% of patients resulting in the lowering of these patients' anti-Xa activity by 50%. Dose reductions were achieved with both types of heparin (low-molecular-weight heparin: 64 ± 14 to 35 ± 12 IU/kg, P < 0.0001; unfractionated heparin: 82 ± 18 to 46 ± 13 IU/kg, P < 0.0001) resulting in a decrease of anti-Xa activity at dialysis session end (low-molecular-weight heparin: 0.51 ± 0.25 to 0.25 ± 0.11 IU/mL, P < 0.0001; unfractionated heparin: 0.28 ± 0.23 to 0.13 ± 0.07 IU/mL, P < 0.0001). Failure to further decrease heparin dose was related to signs of clotting in blood lines (57% of sessions), in dialyzer (9%), or both (34%). Significant reduction of heparin dose and anti-Xa activity at the end of HD sessions was possible in stable HD patients using heparin-grafted membrane. HD patients who require low anti-Xa activity at the end of HD sessions might benefit from a heparin-grafted membrane to reduce bleeding risk and other heparin adverse events.

Safety of arthrocentesis and joint injection in patients receiving anticoagulation at therapeutic levels

BACKGROUND

Arthrocentesis and joint injections are commonly performed for both diagnostic and therapeutic indications. Because of safety concerns, there is often reluctance to perform these procedures in patients who are receiving anticoagulation at therapeutic levels. This study was undertaken to determine the safety of arthrocentesis and joint injection performed by physicians from different disciplines in patients who are anticoagulated.

METHODS

We conducted a retrospective review of 640 arthrocentesis and joint injection procedures performed in 514 anticoagulated patients between 2001 and 2009. We assessed the incidence of early and late clinically significant bleeding in or around a joint, infection, and procedure-related pain. We further compared the incidence of these complications in 456 procedures performed in patients with an international normalized ratio 2.0 or greater and 184 procedures performed in patients with an international normalized ratio less than 2.0.

RESULTS

Only 1 procedure (0.2%) resulted in early, significant, clinical bleeding in the fully anticoagulated group. There was no statistically significant difference in early and late complications between patients who had procedures performed with an international normalized ratio 2.0 or greater and those whose anticoagulation was adjusted to an international normalized ratio less than 2.0.

CONCLUSION

Arthrocentesis and joint injections in patients receiving chronic warfarin therapy with therapeutic international normalized ratio are safe procedures. There does not seem to be a need for reducing the level of anticoagulation before procedures in these patients.

Potential roles for pharmacists in pharmacogenetics

OBJECTIVES

To highlight areas of pharmacogenetics in which pharmacists may play a role and to describe those roles in the context of specific examples from a major academic medical center.

DATA SOURCES

Literature search (PubMed) and personal interviews for the University of California at San Francisco case examples.

DATA SYNTHESIS

The field of pharmacogenetics presents a wide range of opportunities for pharmacists. Specific roles for pharmacists are likely to fall within three major domains: developing research methodologies and setting research directions, establishing the value of pharmacogenetic testing in clinical practice, and participating in education and infrastructure development that moves pharmacogenetic technologies toward implementation.

CONCLUSION

As drug therapy experts, pharmacists are in a unique position to push the frontiers of pharmacogenetics in both the research and clinical practice environments.

Prospective study of warfarin dosage requirements based on CYP2C9 and VKORC1 genotypes

Polymorphisms in CYP2C9 and VKORC1 have been shown to be associated with warfarin dose requirements and could be used to predict warfarin dose. We conducted a prospective study in which warfarin dose was prescribed based on CYP2C9 and VKORC1 polymorphisms in 108 Han-Chinese patients without prior warfarin treatments. Using the genotype-based dosing, 83% of patients reached stable, therapeutic international normalized ratio (INR) within 2 weeks of treatment initiation and none of the patients developed clinical bleeding or thromboembolic event. Ten percent (11) of patients with INR > 4 and no clinical bleeding were detected during this study. At 12 weeks, 69% of the patients' maintenance doses matched the prediction. Dosing algorithms incorporating genetic factors, age, and body surface area were developed, which could explain up to 62% of the total variation (R(2) of 0.62). This study demonstrated that pharmacogenetics-based dosing could improve time to stable, therapeutic INR, reduce adverse events, and achieve high sensitivity.

Ocular bleeding related to warfarin anticoagulation in patients with mechanical heart valve and atrial fibrillation

We investigated the incidence of ocular bleeding in patients taking anticoagulant therapy (warfarin) and its association with other related factors. We examined 210 patients taking warfarin and 210 gender- and age-matched controls for ocular bleeding. Patients and controls were examined by external ocular examination and fundoscopic examination. The incidence of ocular bleeding was 11.4% in patients and 3.8% in controls. It was five times higher in patients with hypertension than in other patients. The incidence of ocular bleeding was higher in older than in younger patients. No association was found between ocular bleeding and factors such as gender, international normalized ratio, duration of warfarin therapy, concomitant aspirin use and diabetes mellitus. Thus, warfarin therapy increases the frequency of ocular bleeding. The higher incidence of ocular bleeding in the patients with hypertension and advanced age should be kept in mind and this subgroup of patients taking warfarin should be monitored closely.

Perioperative management of the podiatric surgical patient

Advanced thought and planning are required when preparing for podiatric surgery. In addition to appropriate procedure selection and follow-up, perioperative management has a key role in patient and physician satisfaction. Neglect of this aspect of podiatric care can also be a source of malpractice. This article analyzes many of the common medical treatments currently employed and makes recommendations for treatment before, during, and after surgery.

Heparin Inhibits NF-κB Activation and Increases Cell Death in Cerebral Endothelial Cells after Oxygen-Glucose Deprivation

Heparin is a classic anticoagulant that is commonly used in the treatment of acute ischemic stroke (AIS). Its use remains controversial, however, due to the risk of cerebral hemorrhagic transformation. In addition to anticoagulant effects, diverse effects on transcription factors can be caused by heparin. Among the transcription factors potentially affected is nuclear factor kappa B (NF-kappaB), a protein that is reportedly related to the survival of cerebral endothelial cells. We investigated the effect of heparin on NF-kappaB activation and cell death following oxygen-glucose deprivation (OGD), an experimental model of AIS. We subjected bEnd.3 cells from a murine cerebral microvascular endothelial cell line to OGD. We examined the effect of heparin on OGD-induced NF-kappaB activation and its mechanism of action, using electrophoretic mobility shift assays, reporter gene analysis, real-time RT-PCR, Western blot analysis, and confocal microscopy. We also measured the effect of heparin on OGD-induced cell death using an MTT assay. Heparin inhibited both tumor necrosis factor alpha- and OGD-induced NF-kappaB activation. Heparin was taken up by endocytosis and then entered the nucleus. Heparin did not affect the nuclear translocation of NF-kappaB, but instead inhibited the DNA binding of NF-kappaB in the nucleus. Cells were more susceptible to OGD-induced cell death after heparin treatment. Besides producing an anticoagulation effect, heparin also inhibits NF-kappaB activation, resulting in increased susceptibility to OGD-induced cell death. This effect may be responsible for hemorrhagic transformation in patients following heparin treatment for AIS.

A Pharmacotherapy Clinic in a Neurologic Practice

Background:

Limited information exists on therapeutic drug monitoring of neurology patients. Although multiple reviews on anticoagulation clinics have shown good outcomes, the therapeutic endpoints achieved in patients enrolled in a pharmacotherapy clinic serving only those with a history of stroke/transient ischemic attack (TIA) have not been noted previously.

Objective:

To illustrate the drug therapy management role of a pharmacotherapist in a neurology clinic and provide evidence on the quality of the service by presenting data on therapeutic endpoints in the subset of patients who are on anticoagulant therapy for stroke prevention.

Methods:

Reported therapeutic endpoints included recurrent stroke/TIA, bleeding, time in therapeutic range (international normalized ratio [INR] range 2–3), adherence, and patient satisfaction with pharmaceutical care. Patients completed the Morisky self-report compliance questionnaire and the Pharmaceutical Care Satisfaction Questionnaire. Other information included medical history, medications, anticoagulation rationale, referring service, and therapeutic endpoints.

Results:

There were few adverse outcomes of bleeding or stroke. Time in therapeutic range for an INR of 2–3 was 59.67%. Of 251 INRs, 2 (0.8%) were greater than 5. Patient satisfaction with pharmaceutical care was high, as was adherence.

Conclusions:

The incidence of recurrent stroke/TIA and bleeding was rare, despite the inherently higher bleeding risk for stroke patients. Times in range of INRs were equivalent to those of other anticoagulation clinics. Patient satisfaction and adherence were good despite polypharmacy. Pharmacotherapists can be valuable additions to neurology clinics by helping neurologists in the management of the pharmacotherapy of their patients, including those on anticoagulation therapy for stroke/TIA.

Antithrombotic therapy in atrial fibrillation: beyond the AFFIRM study

In the last few decades several clinical studies evaluated the efficacy and safety of different strategies for antithrombotic prophylaxis to prevent thromboembolic events in patients with atrial fibrillation (AF). Nowadays, a frequently debated point is related to the high embolic risk deriving from the asymptomatic and symptomatic AF recurrence after cardioversion or in paroxysmal AF, especially in patients with a large number of prolonged episodes of AF. In fact, after the recent AFFIRM and RACE trials, patients after successful cardioversion at risk for thromboembolism could also need lifelong anticoagulation. Considering this, should we anticoagulate all patients with clinical risk factors for thromboembolism with a single episode of AF, without considering the hemorrhagic risk? Based on recent trials, it is reasonable to hypothesize that long AF recurrences (> 48 h), both symptomatic and asymptomatic, are present mostly (if not exclusively) in patients with structural left atrial appendage (LAA) dysfunction and remodeling. Conversely, AF recurrences in patients without LAA dysfunction and remodeling, could be too short to allow thrombi formation in the LAA, and the anticoagulation could also be avoided. Once other clinical and echocardiographic determinants of stroke have been excluded, the LAA velocity could select patients with a normal appendage function at low embolic risk who could benefit from anti-aggregation and patients with irreversible appendage dysfunction, at high embolic risk, who need lifelong anticoagulation.

Investigating suspected pulmonary embolism during pregnancy

Pulmonary embolism (PE) is the commonest cause of maternal death in UK. It is a frequently occurring diagnostic challenge. The false negative and false positive rates for the diagnosis of PE are spectacularly high. Undiagnosed PE has a mortality rate as high as 30%, which falls to 2-8% if the condition is diagnosed and treated appropriately. [Rodger M, Wells PS. Diagnosis of pulmonary embolism. Thromb Res 2001;103:v225-38; Guidelines on Diagnosis and Management of Acute Pulmonary Embolism. Task Force on Pulmonary Embolism, European Society of Cardiology. Eur Heart J 2000;21(16):1301-36]. Physiologic changes of pregnancy further complicate the diagnosis of PE. Although the danger of maternal and foetal death secondary to maternal PE and unnecessary anticoagulation far outweighs the risk of radiation involved in scanning, doctors still hesitate to request appropriate investigation because of concern regarding radiation exposure to the foetus and the absence of any clear, updated guideline. Worried parents need to be counselled appropriately before tests to alleviate anxiety and misunderstanding.

Oral anticoagulant therapy, endocapsular hematoma, and neodymium:YAG capsulotomy

We present a case of endocapsular hematoma, a rare form of intraocular hemorrhage that developed in a patient with pseudophakia receiving oral anticoagulants for previous mitral valve replacement and cerebrovascular disease.

Low-intensity anticoagulation for stroke prevention in elderly patients with atrial fibrillation: efficacy and safety in actual clinical practice

Low-intensity warfarin (INR 1.5 to 2.5) was started in 63 patients with atrial fibrillation (AF) and they were prospectively followed for 2.3 +/- 1.4 years to determine the efficacy and safety of anticoagulation for stroke prevention in actual clinical practice. Although the patients in this practice were older (76 +/- 7 years), consisted of more women (52%), and had more risk factors for stroke compared with those in clinical trials, the annual event rates of stroke and systemic embolism in this practice were comparable to those of patients receiving warfarin in clinical trials (2.0% vs. 1.4% and 0.7% vs. 0.3%). The rate of major bleeding did not significantly differ between this practice and clinical trials (0.7% vs. 1.3%). The rate of minor bleeding was significantly lower in this practice than in clinical trials (3.4% vs. 7.9%). The data suggest that low-intensity anticoagulation is effective and safe for stroke prevention in elderly patients with AF at stroke risk in actual clinical practice.

Interventional closure with Amplatzer PFO occluder of patent foramen ovale in patients with paradoxical cerebral embolism

Percutaneous transcatheter closure has been proposed as an alternative to surgical closure or long-term anticoagulation in patients with presumed paradoxical embolism and patent foramen ovale (PFO). We report our mid-term results of 55 consecutive symptomatic patients (mean age: 47 years, range: 20-79) who underwent percutaneous transcatheter closure of PFO after at least one event of cerebral ischemia; 16 (29%) patients had at least one transient ischemic attack and 39 (71%) patients at least one embolic stroke. Multiple embolic events had occurred in 6 (11%) patients. Percutaneous transcatheter closure was technically successful in all 55 patients (100%). For the majority of patients, an Amplatzer PFO occluder measuring 25 mm in diameter (n=49) or an Amplatzer PFO occluder measuring 35 mm in diameter (n=6) was used. Complete occlusion by color Doppler and transesophageal contrast echocardiography investigation was achieved in 96% at follow-up 3-6 months after implantation; only 2 patients had a trivial residual shunt at follow-up. Mean fluoroscopy time was 6.7 minutes (range: 1.7-47.1), and in-hospital follow-up was uneventful except for 1 patient who developed a cardiac tamponade requiring uneventful and successful needle pericardiocentesis. At a mean follow-up of 19 months (range: 3-32) no recurrent embolic neurological events was observed. Transcatheter closure of PFO with Amplatzer PFO occluder devices is a safe and effective therapy for patients with previous paradoxical embolism and aneurysmatic or nonaneurysmatic PFO. Percutaneous closure is associated with a high success rate, low incidence of hospital complications, and freedom of cerebral ischemia events.

Pre- and post-cardioversion transesophageal echocardiography for brief anticoagulation therapy with enoxaparin in atrial fibrillation patients: a prospective study with a 1-year follow-up

BACKGROUND

In patients with atrial fibrillation (AF) eligible for electrical cardioversion (C), the guided approach with transesophageal echocardiography (TEE) allows to avoid the 3 weeks of recommended precardioversion anticoagulation therapy. However, after sinus rhythm restoration, at least other 4 weeks of oral anticoagulation therapy are indicated, due to the postcardioversion thromboembolic risk related to left atrial (LA) and left atrial appendage (LAA) stunning. The aim of this study was to prospectively assess the effectiveness and the safety of anticoagulation therapy discontinuation 7 days after C using low-molecular-weight heparins (LMWH) in a selected group of patients who underwent a pre-C and 7 days post-C TEE evaluation.

METHODS

One hundred one patients (74 patients with nonvalvular AF and 27 patients with atrial flutter lasting >48 h and history of AF) were enrolled into the study. Two patients refused the TEE, therefore, in 99/101, we performed a first TEE and, within 24 h, a C if there were no LAA thrombi, complex aortic plaques or severe spontaneous echocontrast. After C and 7 days of home-administered enoxaparin, a second TEE was carried out. In the absence of any new thrombi, severe spontaneous echocontrast and/or low emptying velocity of LAA, the therapy with enoxaparin was stopped; otherwise, anticoagulation therapy with enoxaparin was overlapped with oral anticoagulation and continued for at least 3 weeks. All patients were clinically followed at 1, 6 and 12 months after C.

RESULTS

Sinus rhythm was restored in 68/99 patients after successful C. The second TEE was carried out in 53 patients. At 1 month follow-up, no thromboembolic events were recorded either in patients at risk who had continued the oral anticoagulant therapy for at least 3 weeks or in those who suspended LMWH after 7 days post-C TEE. Between the 2nd and 12th month, three ischemic strokes occurred, all in the group of patients who had anticoagulation therapy for at least 3 weeks and had shown LAA velocity <25 cm/s at first or second TEE. No thromboembolic events were recorded in patients with normal LAA velocity; conversely, among the patients who had shown low LAA velocity at either TEE, three suffered from ischemic stroke. In two of these three patients, low LAA velocity was detected only at post-C TEE.

CONCLUSIONS

A brief anticoagulation therapy using LMWH appears to be safe and feasible. The 7 days post-C TEE can well-define patients without LAA stunning at low thromboembolic risk, who may take advantage of an early interruption of enoxaparin as an alternative to long oral anticoagulation. The LAA stunning, even in the absence of other thromboembolic risk factors, could select a group of patients at high risk who should continue oral anticoagulation indefinitely or until signs of LAA dysfunction disappear.

Acute upper gastrointestinal bleeding in patients on long-term oral anticoagulation therapy: endoscopic findings, clinical management and outcome

AIM

Acute gastrointestinal bleeding is a severe complication in patients receiving long-term oral anticoagulant therapy. The purpose of this study was to describe the causes and clinical outcome of these patients.

METHODS

From January 1999 to October 2003, 111 patients with acute upper gastrointestinal bleeding (AUGIB) were hospitalized while on oral anticoagulants. The causes and clinical outcome of these patients were compared with those of 604 patients hospitalized during 2000-2001 with AUGIB who were not taking warfarin.

RESULTS

The most common cause of bleeding was peptic ulcer in 51 patients (45%) receiving anticoagulants compared to 359/604 (59.4%) patients not receiving warfarin (P < 0.05). No identifiable source of bleeding could be found in 33 patients (29.7%) compared to 31/604 (5.1%) patients not receiving anticoagulants (P = 0.0001). The majority of patients with concurrent use of non-steroidal anti-inflammatory drugs (NSAIDs) (26/35, 74.3%) had a peptic ulcer as a cause of bleeding while 32/76 (40.8%) patients not taking a great dose of NSAIDs had a negative upper and lower gastrointestinal endoscopy. Endoscopic hemostasis was applied and no complication was reported. Six patients (5.4%) were operated due to continuing or recurrent hemorrhage, compared to 23/604 (3.8%) patients not receiving anticoagulants. Four patients died, the overall mortality was 3.6% in patients with AUGIB due to anticoagulants, which was not different from that in patients not receiving anticoagulant therapy.

CONCLUSION

Patients with AUGIB while on long-term anticoagulant therapy had a clinical outcome, which is not different from that of patients not taking anticoagulants. Early endoscopy is important for the management of these patients and endoscopic hemostasis can be safely applied.

Clinicians' Response to Radiologists' Reports of Isolated Subsegmental Pulmonary Embolism or Inconclusive Interpretation of Pulmonary Embolism Using MDCT

OBJECTIVE

The purpose of our study was to investigate clinician response and patient outcome associated with the radiologist's report of isolated subsegmental pulmonary emboli (ISSPE) or indeterminate or inconclusive results on MDCT for venous thromboembolism.

MATERIALS AND METHODS

All patients were examined using 8- or 16-MDCT. Reported findings on combined CT pulmonary angiography and CT venography of 1,435 consecutive patients were analyzed retrospectively. The charts of patients of interest with ISSPE or with indeterminate or inconclusive pulmonary embolism results were analyzed for clinician response and recurrent symptoms of venous thromboembolism in both treated and untreated patients during the following 3 months.

RESULTS

We studied 207 patients of interest, and follow-up was available on 192 (92.8%) (67 ISSPEs, 125 inconclusive). Of the 192 patients, 25 (37%) of 67 patients with ISSPE and 108 (86%) of 125 patients with inconclusive results did not receive anticoagulation. Two patients with ISSPE and two patients with inconclusive results returned with new symptoms suggesting recurrent venous thromboembolism, but no venous thromboembolism was found. Thirteen (10%) of 133 untreated patients died without clinical evidence of recurrent venous thromboembolism. In 61 patients who received anticoagulation (42/67 [63%] ISSPE and 17/125 [14%] inconclusive), five patients returned with venous thromboembolism symptoms. None had recurrent emboli. Two (3%) of 61 patients who received anticoagulation died of other diseases.

CONCLUSION

Patients with ISSPE more commonly received anticoagulation than not. In the patients who did not receive anticoagulation, no recurrent pulmonary embolism was identified on follow-up. In most patients with inconclusive findings on CT pulmonary angiography, clinicians chose to withhold anticoagulation without additional imaging workup. No adverse effects of this clinical decision were uncovered.

Other supportive therapies in sepsis: an evidence-based review

OBJECTIVE

In 2003, critical care and infectious disease experts representing 11 international organizations developed management guidelines for other supportive therapies in sepsis that would be of practical use for the bedside clinician, under the auspices of the Surviving Sepsis Campaign, an international effort to increase awareness and improve outcome in severe sepsis.

DESIGN

The process included a modified Delphi method, a consensus conference, several subsequent smaller meetings of subgroups and key individuals, teleconferences, and electronic-based discussion among subgroups and among the entire committee.

METHODS

The modified Delphi methodology used for grading recommendations built on a 2001 publication sponsored by the International Sepsis Forum. We undertook a systematic review of the literature graded along five levels to create recommendation grades from A to E, with A being the highest grade. Pediatric considerations to contrast adult and pediatric management are in the article by Parker et al. on p. S591.

CONCLUSION

Patients with severe sepsis should be treated with deep-vein thrombosis prophylaxis. Low-dose unfractionated heparin or low molecular weight heparin is preferred. Use of graduated compression devices is recommended in septic patients with contraindication to the use of heparin or combined with heparin in very high-risk patients. Stress ulcer prophylaxis should be given to all patients with severe sepsis. Histamine-2 receptor antagonists are more effective than sucralfate in decreasing bleeding risk and transfusion requirements. Proton pump inhibitors have not been assessed in a direct comparison with histamine-2 receptor antagonists but do demonstrate equivalency and ability to increase gastric pH.

Usefulness of clinical prediction rules for the diagnosis of venous thromboembolism: a systematic review

PURPOSE

To summarize the evidence on the predictive value of clinical prediction rules for the diagnosis of venous thromboembolism.

METHODS

We selected all studies in the English literature in which a clinical prediction rule was prospectively validated against a reference standard, and calculated likelihood ratios, predictive values, and the area under the receiver operating characteristic (ROC) curve for each prediction rule.

RESULTS

Twenty-three studies met our eligibility criteria: 17 evaluated prediction rules for the diagnosis of deep venous thrombosis and six evaluated rules for pulmonary embolism. The most frequently evaluated prediction rule for deep vein thrombosis was the Wells rule, which had median positive likelihood ratios of 6.62 for patients with a high pretest probability, 1 for moderate pretest probability, and 0.22 for low pretest probability. The median area under the ROC curve was 0.82. Addition of the D-dimer test to the prediction rule increased the median area under the curve to 0.90. The Wells prediction rule was the most commonly studied for pulmonary embolus and had median positive likelihood ratios of 6.75 for those with high pretest probability, 1.82 for moderate pretest probability, and 0.13 for low pretest probability. The median area under the ROC curve was 0.82.

CONCLUSION

The Wells prediction rule is useful in identifying patients at low risk of being diagnosed with venous thromboembolism. The addition of a rapid latex D-dimer assay improved the overall performance of the prediction rule.

Hemorrhagic Complications of Anticoagulant Treatment

This chapter about hemorrhagic complications of anticoagulant treatment is part of the seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy: Evidence Based Guidelines. Bleeding is the major complication of anticoagulant therapy. The criteria for defining the severity of bleeding varies considerably between studies, accounting in part for the variation in the rates of bleeding reported. The major determinants of vitamin K antagonist-induced bleeding are the intensity of the anticoagulant effect, underlying patient characteristics, and the length of therapy. There is good evidence that vitamin K antagonist therapy, targeted international normalized ratio (INR) of 2.5 (range, 2.0 to 3.0), is associated with a lower risk of bleeding than therapy targeted at an INR > 3.0. The risk of bleeding associated with IV unfractionated heparin (UFH) in patients with acute venous thromboembolism (VTE) is < 3% in recent trials. This bleeding risk may increase with increasing heparin dosages and age (> 70 years). Low molecular weight heparin (LMWH) is associated with less major bleeding compared with UFH in acute VTE. UFH and LMWH are not associated with an increase in major bleeding in ischemic coronary syndromes, but are associated with an increase in major bleeding in ischemic stroke. Information on bleeding associated with the newer generation of antithrombotic agents has begun to emerge. In terms of treatment decision making for anticoagulant therapy, bleeding risk cannot be considered alone, ie, the potential decrease in thromboembolism must be balanced against the potential increased bleeding risk.

Spontaneous spinal hematomas and low-molecular-weight heparin

✓ The purpose of this article is to raise awareness of spontaneous spinal hematomas that develop after administration of low-molecular-weight heparin therapy. The authors describe four patients in whom these hematomas developed without precipitating events while receiving a treatment dose of enoxaparin (Clexane) (∼1 mg/kg). Spontaneous spinal hematomas (not related to trauma, surgery, or lumbar puncture) are a rare clinical entity. Several causes have been identified, including acquired and congenital clotting abnormalities and underlying vascular lesions. Aspirin, warfarin, tissue plasminogen activator, and heparin have all been implicated in causing spinal hematomas. Concerns regarding the use of low-molecular-weight heparin agents in neuraxis anesthesia have been well documented. Their possible contribution to nontraumatic spinal hematomas has been less well described. The authors believe that low-molecular-weight heparin agents present a small but significant risk of spinal hematoma. This should be considered when prescribing therapy because such a complication may be catastrophic.

Individualized duration of oral anticoagulant therapy for deep vein thrombosis based on a decision model

BACKGROUND

The optimal duration of oral anticoagulant therapy for patients with a first episode of deep vein thrombosis (DVT) is still a matter of debate. However, according to the ACCP consensus strategy a limited stratification in treatment duration is advocated, i.e. 3 months for patients with a transient risk factor and 1 year or longer for patients with recurrent disease or a consistent risk factor such as thrombophilia or cancer. This consensus strategy is founded on the mean optimal duration of therapy obtained in large cohorts of patients and is mainly based on the risk of recurrent venous thromboembolism (VTE), with only minimal consideration for the patient's bleeding risk.

OBJECTIVE

The aim of this study is to optimize the anticoagulant treatment strategy with vitamin K antagonists for the individual patient with DVT.

METHODS

Based on an extensive literature study, a mathematical model was constructed to balance the risk of recurrent VTE against the risk of major hemorrhagic complications. The following parameters are incorporated in the model: baseline estimates and risk factors for recurrent VTE and bleeding, clinical course of DVT, and efficacy of treatment with vitamin K antagonists. With the use of these parameters, the risk for a recurrent VTE and a bleeding episode can be calculated for the individual patient. The optimal duration of anticoagulant therapy can be defined as the timepoint at which the benefit of treatment (prevention of VTE) is counterbalanced by its risk (bleeding).

RESULTS/CONCLUSIONS

How long a patient should receive anticoagulant treatment is a matter of balancing the benefits and risks of treatment. The model shows that the optimal treatment duration varies greatly from patient to patient according to the patient's unique bleeding and recurrence risk.

MRI for the diagnosis of pulmonary embolism

Pulmonary embolism (PE) is one of the most frequently encountered clinical emergencies. The diagnosis often involves multiple diagnostic tests, which need to be carried out rapidly to assist in the safe management of the patient. Recent strides in computed tomography (CT) have made big improvements in patient management and efficiency of diagnostic imaging. This review article describes the developments in magnetic resonance (MR) techniques for the diagnosis of acute PE. Techniques include MR angiography (MRA) and thrombus imaging for direct clot visualization, perfusion MR, and combined perfusion-ventilation MR. As will be demonstrated, some of these techniques are now entering the clinical arena, and it is anticipated that MR imaging (MRI) will have an increasing role in the initial diagnosis and follow-up of patients with acute PE.

Patent Foramen Ovale and Stroke

Observational data from prospective and retrospective trials indicate that a patent foramen ovale (PFO) is associated with the risk of ischemic stroke. The mechanism involved is presumed to be paradoxical embolism from a venous thrombus that travels via the PFO to the systemic circulation causing an ischemic stroke. Primary stroke prevention data for patients with a PFO are nonexistent. Given the substantial prevalence of PFO in the total population (~ 25% to 30%), a primary prevention study may not be feasible. However, whether targeted primary prevention for patients with PFOs of certain morphologic characteristics (eg, larger size, greater degree of shunt) would be possible remains undefined. Given the large number of asymptomatic subjects, no therapy is currently recommended. The best treatment modality to prevent recurrent stroke in patients with PFO has not been defined. There are four major treatment choices: surgical closure, percutaneous device closure, medical therapy with anticoagulants, and medical therapy with antiplatelet agents. Regarding medical therapy, the Patent Foramen Ovale in Cryptogenic Stroke Study has demonstrated that antiplatelet and anticoagulant therapies are of equal benefit in preventing recurrent adverse events. Although closure of the PFO, either surgical or percutaneous, may further reduce the event rates, this remains to be demonstrated because no randomized trial to date has compared PFO closure with medical therapy.

CT pulmonary angiography and suspected acute pulmonary embolism

PURPOSE

To evaluate the use and quality of CT pulmonary angiography in our department, and to relate the findings to clinical parameters and diagnoses.

MATERIAL AND METHODS

A retrospective study of 324 consecutive patients referred to CT pulmonary angiography with clinically suspected pulmonary embolism (PE). From the medical records we registered clinical parameters, blood gases, D-dimer, risk factors and the results of other relevant imaging studies.

RESULTS

55 patients (17%) had PE detected on CT. 39 had bilateral PE, and 8 patients had isolated peripheral PE. 87% of the examinations showing PE had satisfactory filling of contrast material including the segmental pulmonary arteries, and 60% of the subsegmental arteries. D-dimer test was performed in 209 patients, 85% were positive. A negative D-dimer ruled out PE detected at CT. Dyspnea and concurrent symptoms or detection of deep vein thrombosis (DVT), contraceptive pills and former venous thromboembolism (VTE) were associated with PE. The presence of only one clinical parameter indicated a negative PE diagnosis (p < 0.017), whereas two or more suggested a positive PE diagnosis (p < 0.002). CT also detected various ancillary findings such as consolidation, pleural effusion, nodule or tumor in nearly half of the patients; however, there was no association with the PE diagnosis.

CONCLUSION

The quality of CT pulmonary angiography was satisfactory as a first-line imaging of PE. CT also showed additional pathology of importance in the chest. Our study confirmed that a negative D-dimer ruled out clinically suspected VTE.

Current trends in preoperative patient evaluation and management for podiatric surgeons

In preparation for elective foot and ankle surgery, the podiatric surgeon often will refer the patient for a preoperative evaluation. Surgeons rely on the input of that consultant to provide a determination as to the operative risk for the patient. This article reviews the fundamental parts of the preoperative evaluation, perioperative patient management, and recent changes and trends within this arena.

Venous thromboembolism in the intensive care unit

Most ICU patients have a significant number of risk factors for VTE. The high incidence of DVT in the ICU population and the recognition of a high incidence of PE at autopsy confirm this. We have alluded to the difficulty of clinical diagnosis of VTE and the need for diagnostic investigations. We have reviewed currently available diagnostic investigations with regard to their sensitivity and specificity and their practicability in ICU patients, and have formulated recommended diagnostic algorithms (Figs. 4 and 5). The most important factor in the management of VTE is prevention. In the ICU, all patients are at high risk for VTE, and therefore, at a minimum should receive subcutaneous prophylactic heparin unless it is contraindicated. Alternative methods of prophylaxis are available, and should be considered for patients who have contraindications to heparin.