Prospective surveillance for perioperative venous thrombosis. Experience in 2643 patients

Presentation and Management of Cerebral Venous Sinus Thrombosis After Supratentorial Craniotomy

BACKGROUND AND OBJECTIVES

Cerebral venous sinus thrombosis (CVST) after supratentorial craniotomy is a poorly studied complication, for which there are no management guidelines. This study assessed the incidence, associated risk factors, and management of postoperative CVST after awake craniotomy.

METHODS

This is an observational, retrospective, monocentric analysis of patients who underwent a supratentorial awake craniotomy. Postoperative CVST was defined as a flow defect on the postoperative contrast-enhanced 3D T1-weighted sequence and/or as a T2* hypointensity within the sinus.

RESULTS

In 401 supratentorial awake craniotomies (87.3% of diffuse glioma), the incidence of postoperative CVST was 4.0% (95% CI 2.5-6.4): 14/16 thromboses located in the superior sagittal sinus and 12/16 located in the transverse sinus. A venous sinus was exposed during craniotomy in 45.4% of cases, and no intraoperative injury to a cerebral venous sinus was reported. All thromboses were asymptomatic, and only two cases were diagnosed at the time of the first postoperative imaging (0.5%). Postoperative complications, early postoperative Karnofsky Performance Status score, and duration of hospital stay did not significantly differ between patients with and without postoperative CVST. Adjusted independent risk factors of postoperative CVST were female sex (adjusted Odds Ratio 4.00, 95% CI 1.24-12.91, P = .021) and a lesion ≤1 cm to a venous sinus (adjusted Odds Ratio 10.58, 95% CI 2.93-38.20, P < .001). All patients received standard prophylactic-dose anticoagulant therapy, and none received treatment-dose anticoagulant therapy. No thrombosis-related adverse event was reported. All thromboses presented spontaneous sinus recanalization radiologically at a mean of 89 ± 41 days (range, 7-171).

CONCLUSION

CVST after supratentorial awake craniotomy is a rare event with satisfactory clinical outcomes and spontaneous sinus recanalization under conservative management without treatment-dose anticoagulant therapy. These findings are comforting to neurosurgeons confronted with postoperative MRI reports suggesting CVST.

Neurocritical Care Performance Measures Derived from Electronic Health Record Data are Feasible and Reveal Site-Specific Variation: A CHoRUS Pilot Project

BACKGROUND

We evaluated the feasibility and discriminability of recently proposed Clinical Performance Measures for Neurocritical Care (Neurocritical Care Society) and Quality Indicators for Traumatic Brain Injury (Collaborative European NeuroTrauma Effectiveness Research in TBI; CENTER-TBI) extracted from electronic health record (EHR) flowsheet data.

METHODS

At three centers within the Collaborative Hospital Repository Uniting Standards (CHoRUS) for Equitable AI consortium, we examined consecutive neurocritical care admissions exceeding 24 h (03/2015-02/2020) and evaluated the feasibility, discriminability, and site-specific variation of five clinical performance measures and quality indicators: (1) intracranial pressure (ICP) monitoring (ICPM) within 24 h when indicated, (2) ICPM latency when initiated within 24 h, (3) frequency of nurse-documented neurologic assessments, (4) intermittent pneumatic compression device (IPCd) initiation within 24 h, and (5) latency to IPCd application. We additionally explored associations between delayed IPCd initiation and codes for venous thromboembolism documented using the 10th revision of the International Statistical Classification of Diseases and Related Health Problems (ICD-10) system. Median (interquartile range) statistics are reported. Kruskal-Wallis tests were measured for differences across centers, and Dunn statistics were reported for between-center differences.

RESULTS

A total of 14,985 admissions met inclusion criteria. ICPM was documented in 1514 (10.1%), neurologic assessments in 14,635 (91.1%), and IPCd application in 14,175 (88.5%). ICPM began within 24 h for 1267 (83.7%), with site-specific latency differences among sites 1-3, respectively, (0.54 h [2.82], 0.58 h [1.68], and 2.36 h [4.60]; p < 0.001). The frequency of nurse-documented neurologic assessments also varied by site (17.4 per day [5.97], 8.4 per day [3.12], and 15.3 per day [8.34]; p < 0.001) and diurnally (6.90 per day during daytime hours vs. 5.67 per day at night, p < 0.001). IPCds were applied within 24 h for 12,863 (90.7%) patients meeting clinical eligibility (excluding those with EHR documentation of limiting injuries, actively documented as ambulating, or refusing prophylaxis). In-hospital venous thromboembolism varied by site (1.23%, 1.55%, and 5.18%; p < 0.001) and was associated with increased IPCd latency (overall, 1.02 h [10.4] vs. 0.97 h [5.98], p = 0.479; site 1, 2.25 h [10.27] vs. 1.82 h [7.39], p = 0.713; site 2, 1.38 h [5.90] vs. 0.80 h [0.53], p = 0.216; site 3, 0.40 h [16.3] vs. 0.35 h [11.5], p = 0.036).

CONCLUSIONS

Electronic health record-derived reporting of neurocritical care performance measures is feasible and demonstrates site-specific variation. Future efforts should examine whether performance or documentation drives these measures, what outcomes are associated with performance, and whether EHR-derived measures of performance measures and quality indicators are modifiable.

Posterior Fossa Hemorrhage Following the Use of Low-Molecular-Weight Heparin: Lessons Learned and Recommendations for the Treatment and Prophylaxis of Postoperative Venous Thromboembolism

Introduction Venous thromboembolism (VTE) is the most common preventable cause of morbidity and mortality among neurosurgery patients. Several studies have concluded that the use of chemical prophylaxis among patients undergoing a craniotomy reduces the incidence of VTE, and it is presumed to be safe. However, these studies do not differentiate between a supratentorial and posterior fossa craniotomy. Furthermore, the prophylactic or therapeutic use of low-molecular-weight heparin (LMWH) has been reported to increase the risk of intracranial hemorrhage. In this study, we describe the clinical details and outcomes for all patients who underwent posterior fossa craniotomy and developed posterior fossa hemorrhage secondary to postoperative use of LMWH during the study period. We also propose recommendations pertaining to postoperative heparin use after posterior fossa surgeries. Methods Data were retrospectively collected for patients presenting with posterior fossa hemorrhage following anticoagulant use among those who previously underwent posterior fossa craniotomy by the senior author (R.W.P.) from January 1, 2011, through December 31, 2018. Results We identified five patients who experienced postoperative hemorrhage while receiving LMWH in the initial setting of posterior fossa craniotomy. After hemorrhaging, four patients had low Glasgow Outcome Scale (GOS) scores (≤3) and failed to return to their baseline neurological status. These four patients had a Glasgow Coma Scale (GCS) score of 15/15 in the immediate postoperative period and received heparin within 72 hours of surgery. Conclusions Based on our findings, there is a possible association between the increased risk of hemorrhage and the early postoperative use of LMWH. The debilitating outcomes among the majority of these patients warrant the cautious use and further investigation of postoperative LMWH to appropriately quantify the risk. Further comparative studies with a larger sample size are required to provide insight into the pathophysiology of our findings.

Incidence of venous thromboembolism in hospitalized pediatric neurosurgical patients: a retrospective 25-year institutional experience

PURPOSE

Venous thromboembolism (VTE) refers to both deep venous thrombosis (DVT) and pulmonary embolism (PE). The risk of VTE in adult neurosurgical patients is thoroughly studied. However, the incidence and risk of VTE in a comprehensive pediatric neurosurgical population is not well-defined. The available pediatric data consists of reviews of specific high-risk groups, such as trauma, critical care, or cancer patients. This may not be reflective of the entire spectrum of a high-volume pediatric neurosurgery practice. This study was undertaken to analyze the incidence and risk factors of VTE in all hospitalizations evaluated by a pediatric neurosurgery service over a 25-year period.

METHODS

A retrospective review of electronic medical records was performed for 9149 hospitalizations in 6374 unique patients evaluated by the pediatric neurosurgery service at Riley Hospital for Children (Indianapolis, IN, USA) from 1990-2014. During this time period, there was no standardized VTE prevention protocol. The study group included all patients less than 18 years of age. Patients with a known pre-existing VTE or pregnancy were excluded.

RESULTS

VTE was diagnosed in 20 of the 9149 (0.22%) hospitalizations, in 18 unique patients. All DVTs were diagnosed via Doppler ultrasound and/or computed tomography. Anatomic clot locations included 9 in the upper extremity (0.098% of hospitalizations), 8 in the lower extremity (0.087%), and 4 (0.044%) pulmonary emboli. Ten of the 20 occurred in hospitalizations where the patient underwent surgery, although the need for surgery was not a statistically significant risk factor. Sixteen of the 20 (80%) occurred in patients with at least one form of central venous line (p < 0.00001). There was one VTE-related death (0.01%).

CONCLUSIONS

In all pediatric neurosurgical patients, a VTE was found in 0.22% of hospitalizations over a 25-year span. Statistically significant risk factors for VTE included central venous line placement, paralysis, malignancy, intubation greater than 48 h, and hypercoagulable state.

Risk of symptomatic venous thromboembolism after abdominal aortic aneurysm repair in long-term follow-up of 1021 consecutive patients

OBJECTIVE

Venous thromboembolism (VTE), including deep venous thrombosis and pulmonary embolism (PE), is an infrequent but consequential and potentially preventable complication after major surgical procedures. The aim of the study was to describe the long-term occurrence of symptomatic VTE in patients undergoing abdominal aortic aneurysm (AAA) repair and to ascertain patient-specific risk factors as well as to compare the rate with that of a reference population.

METHODS

The study included all patients who had undergone endovascular or open AAA repair, both elective and urgent/acute cases, at the Tampere University Hospital (Finland) between February 2001 and December 2016; 59% of patients had undergone endovascular and 41% open repair, and 23% of all cases had required urgent or emergency treatment. Information about later treatment episodes for symptomatic VTE and survival data were obtained from national registries. The reference population was obtained from national registries with a random sample of inhabitants matched for age, sex, and location of residence with a 4:1 ratio and was analyzed similarly.

RESULTS

Altogether, 1021 patients and 4065 controls were included (88% male; median age, 74 years in both groups). The high-risk period for VTE lasted for approximately 3 months, and during that time, its occurrence was highest in patients with coronary disease (2.5%), after open repair (2.4%), and in an urgent or emergency setting (2.6%), whereas the rate was low after endovascular aneurysm repair (1.0%). The cumulative incidence of VTE at 3 months, 1 year, 3 years, and 5 years was 1.1%, 1.6%, 2.7%, and 4.5% in patients and 0.1%, 0.3%, 1.0%, and 1.8% in the reference population, respectively (P < .001 each). Most VTE events were PE in the patient group. The 5-year mortality rates were 37.9% in patients and 23.8% in controls (P < .001).

CONCLUSIONS

The incidence of symptomatic VTE, particularly PE, after AAA repair is significant, in both short-term and long-term follow-up. Open surgery, acute setting, and concomitant coronary disease appear to increase the risk.

Point-of-care ultrasound for deep venous thrombosis of the lower limb

The incidence and morbidity of deep venous thrombosis (DVT) and pulmonary embolus are high. Although efforts to increase screening for DVT have been recommended, this is limited by resources. Venous duplex ultrasound has replaced venography as the first-line investigation of choice for DVT, increasing availability and reducing patient exposure to radiation and intravenous contrast. Furthermore, an abbreviated ultrasound where DVT is inferred from incomplete venous compressibility has an equivalent accuracy to venous duplex, requiring less time and training enabling its widespread use by emergency, critical care and anaesthesia clinicians. In this review, the evolution and method of lower limb venous compression ultrasound is described along with evidence for its use in patients at high risk for DVT in these clinical settings.

Screening duplex ultrasonography in neurosurgery patients does not correlate with a reduction in pulmonary embolism rate or decreased mortality

OBJECTIVE

Deep vein thrombosis (DVT) is a major focus of patient safety indicators and a common cause of morbidity and mortality. Many practices have employed lower-extremity screening ultrasonography in addition to chemoprophylaxis and the use of sequential compression devices in an effort to reduce poor outcomes. However, the role of screening in directly decreasing pulmonary emboli (PEs) and mortality is unclear. At the University of Mississippi Medical Center, a policy change provided the opportunity to compare independent groups: patients treated under a prior paradigm of weekly screening ultrasonography versus a post-policy change group in which weekly surveillance was no longer performed.

METHODS

A total of 2532 consecutive cases were reviewed, with a 4-month washout period around the time of the policy change. Criteria for inclusion were admission to the neurosurgical service or consultation for ≥ 72 hours and hospitalization for ≥ 72 hours. Patients with a known diagnosis of DVT on admission or previous inferior vena cava (IVC) filter placement were excluded. The primary outcome examined was the rate of PE diagnosis, with secondary outcomes of all-cause mortality at discharge, DVT diagnosis rate, and IVC filter placement rate. A p value < 0.05 was considered significant.

RESULTS

A total of 485 patients met the criteria for the pre-policy change group and 504 for the post-policy change group. Data are presented as screening (pre-policy change) versus no screening (post-policy change). There was no difference in the PE rate (2% in both groups, p = 0.72) or all-cause mortality at discharge (7% vs 6%, p = 0.49). There were significant differences in the lower-extremity DVT rate (10% vs 3%, p < 0.01) or IVC filter rate (6% vs 2%, p < 0.01).

CONCLUSIONS

Based on these data, screening Doppler ultrasound examinations, in conjunction with standard-of-practice techniques to prevent thromboembolism, do not appear to confer a benefit to patients. While the screening group had significantly higher rates of DVT diagnosis and IVC filter placement, the screening, additional diagnoses, and subsequent interventions did not appear to improve patient outcomes. Ultimately, this makes DVT screening difficult to justify.

Incidence and Risk Factors for Venous Thromboembolism After Spine Surgery in Korean Patients

BACKGROUND

Data regarding the incidence of venous thromboembolism (VTE) after spine surgery are scarce. Identifying ideal candidates for pharmacologic thromboprophylaxis and balancing the risk of thromboembolic complications against the risk of permanent neurologic deficits from a spinal epidural hematoma (SEH) are difficult. Even guidelines cannot suggest the standard of thromboprophylaxis.

OBJECTIVES

This study aimed to identify the incidence of and risk factors for VTE after spine surgery in the Korean population. In addition, the rate of pharmacoprophylaxis and the incidence of SEH after spine surgery were analyzed.

METHODS

The study cohort was generated by extracting patients with disease codes of spine surgery and VTE from the Health Insurance Review & Assessment Service National Inpatient Sample in 2014. After analyzing the incidence of VTE after spine surgery, a univariate comparison was performed to examine the possible relationship between the incidence of VTE and the independent variable. Variables found to be significant were included in a multivariable analysis model for further analysis.

RESULTS

The incidence of VTE was 2.09% among all 21,261 patients who had spine surgery, and prophylaxis was applied to 7.89% of all patients who had spine surgery. Comorbidities and surgery-related risk factors were venous disease, cancer, respiratory disease, prolonged surgery hours, and increased total blood loss. Hospital-related risk factors were the location and hospital size.

CONCLUSIONS

On the basis of the incidence of VTE and the risk factors, more active prophylaxis is suggested for patients in the Korean population who undergo spine surgery.

Venous thromboembolic events in patients undergoing craniotomy for tumor resection: incidence, predictors, and review of literature

OBJECTIVE

The authors sought to investigate the incidence and predictors of venous thromboembolic events (VTEs) after craniotomy for tumor resection, which are not well established, and the efficacy of and risks associated with VTE chemoprophylaxis, which remains controversial.

METHODS

The authors investigated the incidence of VTEs in a consecutive series of patients presenting to the authors' institution for resection of an intracranial lesion between 2012 and 2017. Information on patient and tumor characteristics was collected and independent predictors of VTEs were determined using stepwise multivariate logistic regression analysis. Review of the literature was performed by searching MEDLINE using the keywords "venous thromboembolism," "deep venous thrombosis," "pulmonary embolism," "craniotomy," and "brain neoplasms."

RESULTS

There were 1622 patients included for analysis. A small majority of patients were female (52.6%) and the mean age of the cohort was 52.9 years (SD 15.8 years). A majority of intracranial lesions were intraaxial (59.3%). The incidence of VTEs was 3.0% and the rates of deep venous thromboses and pulmonary emboli were 2.3% and 0.9%, respectively. On multivariate analysis, increasing patient age (unit OR 1.02, 95% CI 1.00-1.05; p = 0.018), history of VTE (OR 7.26, 95% CI 3.24-16.27; p < 0.001), presence of motor deficit (OR 2.64, 95% CI 1.43-4.88; p = 0.002), postoperative intracranial hemorrhage (OR 4.35, 95% CI 1.51-12.55; p < 0.001), and prolonged intubation or reintubation (OR 3.27, 95% CI 1.28-8.32; p < 0.001) were independently associated with increased odds of a VTE. There were 192 patients who received VTE chemoprophylaxis (11.8%); the mean postoperative day of chemoprophylaxis initiation was 4.6 (SD 3.8). The incidence of VTEs was higher in patients receiving chemoprophylaxis than in patients not receiving chemoprophylaxis (8.3% vs 2.2%; p < 0.001). There were 30 instances of clinically significant postoperative hemorrhage (1.9%), with only 1 hemorrhage occurring after initiation of VTE chemoprophylaxis (0.1%).

CONCLUSIONS

The study results show the incidence and predictors of VTEs after craniotomy for tumor resection in this patient population. The incidence of VTE within this cohort appears low and comparable to that observed in other institutional series, despite the lack of routine prophylactic anticoagulation in the postoperative setting.

Risk of Deep vein thrombosis in neurosurgery: State of the art on prophylaxis protocols and best clinical practices

OBJECTIVE

To analytically discuss some protocols in Deep vein thrombosis (DVT)/pulmonary Embolism (PE) prophylaxis currently use in Neurosurgical Departments around the world.

DATA SOURCES

Analysis of the prophylaxis protocols in the English literature: An analytical and narrative review of literature concerning DVT prophylaxis protocols in Neurosurgery have been conducted by a PubMed search (back to 1978).

DATA EXTRACTION

80 abstracts were reviewed, and 74 articles were extracted.

DATA ANALYSIS

The majority of DVT seems to develop within the first week after a neurosurgical procedure, and a linear correlation between the duration of surgery and DVT occurrence has been highlighted. The incidence of DVT seems greater for cranial (7.7%) than spinal procedures (1.5%). Although intermittent pneumatic compression (IPC) devices provided adequate reduction of DVT/PE in some cranial and combined cranial/spinal series, low-dose subcutaneous unfractionated heparin (UFH) or low molecular-weight heparin (LMWH) further reduced the incidence, not always of DVT, but of PE. Nevertheless, low-dose heparin-based prophylaxis in cranial and spinal series risks minor and major postoperative haemorrhages: 2-4% in cranial series, 3.4% minor and 3.4% major haemorrhages in combined cranial/spinal series, and a 0.7% incidence of major/minor haemorrhages in spinal series.

CONCLUSION

This analysis showed that currently most of the articles are represented by case series and case reports. As long as clear guidelines will not be defined and universally applied to this diverse group of patients, any prophylaxis for DVT and PE should be tailored to the individual patient with cautious assessment of benefits versus risks.

Risk of deep venous thrombosis in elective neurosurgical procedures: a prospective, Doppler ultrasound-based study in children 12 years of age or younger

OBJECTIVE The risk of venous thromboembolism (VTE) from deep venous thrombosis (DVT) is significant in neurosurgical patients. VTE is considered a leading cause of preventable hospital deaths and preventing DVT is a closely monitored quality metric, often tied to accreditation, hospital ratings, and reimbursement. Adult protocols include prophylaxis with anticoagulant medications. Children's hospitals may adopt adult protocols, although the incidence of DVT and the risk or efficacy of treatment is not well defined. The incidence of DVT in children is likely less than in adults, although there is very little prospectively collected information. Most consider the risk of DVT to be extremely low in children 12 years of age or younger. However, this consideration is based on tradition and retrospective reviews of trauma databases. In this study, the authors prospectively evaluated pediatric patients undergoing a variety of elective neurosurgical procedures and performed Doppler ultrasound studies before and after surgery. METHODS A total of 100 patients were prospectively enrolled in this study. All of the patients were between the ages of 1 month and 12 years and were undergoing elective neurosurgical procedures. The 91 patients who completed the protocol received a bilateral lower-extremity Doppler ultrasound examination within 48 hours prior to surgery. Patients did not receive either medical or mechanical DVT prophylaxis during or after surgery. The ultrasound examination was repeated within 72 hours after surgery. An independent, board-certified radiologist evaluated all sonograms. We prospectively collected data, including potential risk factors, details of surgery, and details of the clinical course. All patients were followed clinically for at least 1 year. RESULTS There was no clinical or ultrasound evidence of DVT or VTE in any of the 91 patients. There was no clinical evidence of VTE in the 9 patients who did not complete the protocol. CONCLUSIONS In this prospective study, no DVTs were found in 91 patients evaluated by ultrasound and 9 patients followed clinically. While the study is underpowered to give a definitive incidence, the data suggest that the risk of DVT and VTE is very low in children undergoing elective neurosurgical procedures. Prophylactic protocols designed for adults may not apply to pediatric patients. Clinical trial registration no.: NCT02037607 (clinicaltrials.gov).

Incidence and risk factors for preoperative deep venous thrombosis in 314 consecutive patients undergoing surgery for spinal metastasis

OBJECTIVE The authors of this study aimed to identify the incidence of and risk factors for preoperative deep venous thrombosis (DVT) in patients undergoing surgical treatment for spinal metastases. METHODS Univariate analysis of patient age, sex, ethnicity, laboratory values, comorbidities, preoperative ambulatory status, histopathological classification, spinal level, and surgical details was performed. Factors significantly associated with DVT univariately were entered into a multivariate logistic regression model. RESULTS The authors identified 314 patients, of whom 232 (73.9%) were screened preoperatively for a DVT. Of those screened, 22 (9.48%) were diagnosed with a DVT. The screened patients were older (median 62 vs 55 years, p = 0.0008), but otherwise similar in baseline characteristics. Nonambulatory status, previous history of DVT, lower partial thromboplastin time, and lower hemoglobin level were statistically significant and independent factors associated with positive results of screening for a DVT. Results of screening were positive in only 6.4% of ambulatory patients in contrast to 24.4% of nonambulatory patients, yielding an odds ratio of 4.73 (95% CI 1.88-11.90). All of the patients who had positive screening results underwent preoperative placement of an inferior vena cava filter. CONCLUSIONS Patients requiring surgery for spinal metastases represent a population with unique risks for venous thromboembolism. This study showed a 9.48% incidence of DVT in patients screened preoperatively. The highest rates of preoperative DVT were identified in nonambulatory patients, who were found to have a 4-fold increase in the likelihood of harboring a DVT. Understanding the preoperative thrombotic status may provide an opportunity for early intervention and risk stratification in this critically ill population.

Presentation and management of lateral sinus thrombosis following posterior fossa surgery

OBJECTIVE There are no guidelines for the management of postoperative lateral sinus thrombosis following posterior fossa surgery. Introducing treatment-dose anticoagulant therapy during the immediate postoperative period increases the risk of intracranial bleeding. This study assessed the incidence of and risk factors associated with postoperative lateral sinus thrombosis and the complications related to thrombosis and/or anticoagulation. METHODS This study was a retrospective monocentric analysis of adult patients who underwent surgical removal of a posterior fossa space-occupying lesion with available postoperative imaging. Postoperative lateral sinus thrombosis was defined as a T2^* hypointensity within the venous sinus and/or a filling defect on postcontrast MRI or CT scan. RESULTS Among 180 patients, 12 (6.7%; 95% CI 3.0-10.4) were found to have lateral sinus thrombosis on postoperative imaging, none of whom were symptomatic. Unadjusted risk factors for postoperative lateral sinus thrombosis were a history of deep venous thrombosis (p = 0.016), oral contraceptive pill (p = 0.004), midline surgical approach (p = 0.035), and surgical exposure of the sinus (p < 0.001). Seven of the patients (58.3%) with a postoperative lateral sinus thrombosis received immediate treatment-dose anticoagulant therapy. Lateral sinus recanalization occurred radiologically at a mean time of 272 ± 23 days in 85.7% of patients (6 of 7) undergoing treatment-dose anticoagulant therapy and in 20% of patients (1 of 5) not receiving treatment-dose anticoagulant therapy. Postoperative complications occurred in 56.2% of patients (9 of 16) who received treatment-dose curative anticoagulant therapy and in 27% of patients (45 of 164) who did not. CONCLUSIONS Incidental radiological lateral sinus thrombosis following posterior fossa surgery has an incidence of 6.7%. To further define the benefit-to-risk ratio of a treatment-dose anticoagulant therapy, a prospective trial should be considered.

Aggressive venous thromboembolism prophylaxis reduces VTE events in vascular surgery patients

Objective

Venous thromboembolism (VTE) is a potentially preventable complication following surgery. There is variation with regard to the most effective mode of prophylaxis. We sought to determine if an aggressive approach to VTE prophylaxis would reduce VTE rates on the inpatient vascular surgical service.

Methods

Vascular inpatients from a single institution from July 2010 to March 2013 were included in the analysis. A protocol for VTE prophylaxis was implemented on the inpatient vascular surgical service in November 2011. This included subcutaneous (SQ) heparin initiation within 24 h of admission unless deemed inappropriate by the attending, as well as intermittent compression devices (ICD) and compression stockings (CS). The rate of VTE was compared prior to and following the intervention. Patients were compared using AHRQ comorbidity categories, APR-DRG severity of illness, insurance status, and principle procedure. T-tests were used to compare continuous variables and chi-square analysis used to compare categorical variables.

Results

There were 1483 vascular patients in the pre-intervention group and 1652 patients in the post-intervention group. The rate of pharmacologic prophylaxis was 52.57% pre-intervention compared to 69.33% post-intervention ( p < 0.001). The rate of pharmacologic or mechanical prophylaxis was 91.76% pre-intervention compared to 93.10% post-intervention ( p = 0.54). The overall rate of VTE prior to the intervention was 1.49% compared to after intervention which was 0.38% ( p = 0.033). The DVT rate prior to intervention was 1.09% vs 0.189% after intervention ( p = 0.0214). The rate of pulmonary embolism trended towards a significant reduction with the intervention (0.681% vs 0.189%, p = 0.095). There were no statistically significant differences in patient groups based on gender, comorbidity category, severity of illness, or insurance type.

Conclusions

The overall rate of VTE was reduced by 75% after the initiation of a standard protocol for pharmacologic VTE prophylaxis. These findings justify an aggressive approach to VTE prophylaxis in vascular surgery patients.

An analysis of deep vein thrombosis in 1277 consecutive neurosurgical patients undergoing routine weekly ultrasonography

Object

Patients requiring neurosurgical intervention are known to be at increased risk for deep vein thrombosis (DVT) and attendant morbidity and mortality. Pulmonary embolism (PE) is the most catastrophic sequela of DVT and is the direct cause of death in 16% of all in-hospital mortalities. Protocols for DVT screening and early detection, as well as treatment paradigms to prevent PE in the acute postoperative period, are needed in neurosurgery. The authors analyzed the effectiveness of weekly lower-extremity venous duplex ultrasonography (LEVDU) in patients requiring surgical intervention for cranial or spinal pathology for detection of DVT and prevention of PE.

Methods

Data obtained in 1277 consecutive patients admitted to a major tertiary care center requiring neurosurgical intervention were retrospectively reviewed. All patients underwent admission (within 1 week of neurosurgical intervention) LEVDU as well as weekly LEVDU surveillance if the initial study was normal. Additional LEVDU was ordered in any patient in whom DVT was suspected on daily clinical physical examination or in patients in whom chest CT angiography confirmed a pulmonary embolus. An electronic database was created and statistical analyses performed.

Results

The overall incidence of acute DVT was 2.8% (36 patients). Of these cases of DVT, a statistically significant greater number (86%) were discovered on admission (within 1–7 days after admission) screening LEVDU (p < 0.05), whereas fewer were documented 8–14 days after admission (2.8%) or after 14 days (11.2%) postadmission. Additionally, for acute DVT detection in the present population, there were no underlying statistically significant risk factors regarding baseline physical examination, age, ambulatory status, or type of surgery.

The overall incidence of acute symptomatic PE was 0.3% and the mortality rate was 0%.

Conclusions

Performed within 1 week of admission in patients who will undergo neurosurgical intervention, LEVDU is effective in screening for acute DVT and initiating treatment to prevent PE, thereby decreasing the overall mortality rate. Routine LEVDU beyond this time point may not be needed to detect DVT and prevent PE unless a change in the patient's physical examination status is detected.

Impact of screening versus symptomatic measurement of deep vein thrombosis in a national quality improvement registry

BACKGROUND

Deep vein thrombosis (DVT) is a quality measure recorded by initiatives such as the National Surgical Quality Improvement Program (NSQIP). However, because surveillance-detected DVT rates may be higher than symptomatic DVT rates, we examined how differences in the method of DVT detection may affect the use of this quality measure.

METHODS

Using the NSQIP database (2007-2009), we compared DVT rates of vascular (amputation, open aortic procedures, and lower extremity bypass) and nonvascular (prostatectomy, gastric bypass [GBP], and hip arthroplasty) operations. Using a predefined literature search strategy, we compared the incidence of DVT in NSQIP to the incidence of DVT reported in published literature, diagnosed by symptomatic status or by surveillance studies.

RESULTS

Within NSQIP, the overall incidence of postoperative DVT was 0.7%. This varied from 0.3% after GBP to 1.8% after open aortic surgery. Across all procedures except amputation, the incidence of DVT in NSQIP was similar to the incidence of DVT reported in our literature survey of "symptomatic" DVTs. The relative rate (RR) of literature-derived symptomatic DVTs to NSQIP ranged from 0.7 for aortic cases (95% confidence interval [CI], 0.3-1.7) to 1.4 (95% CI, .7-3.1) for GBP. Overall, surveillance studies had 11.6 higher RR of DVT compared to NSQIP (95% CI, 10.5-13), ranging from 2.6 for GBP (95% CI, 1.4-5) to 14 .5 for hip arthroplasty (95% CI, 10.5-20).

CONCLUSIONS

The incidence of DVT reported in NSQIP is similar to the reported incidence of symptomatic DVT for many high-risk procedures but is much lower than rates of DVT reported in surveillance studies. Clear delineation of symptomatic vs surveillance detection of DVT would improve the usefulness of this measurement in quality improvement registries.

Prevalence of breast cancer treatment sequelae over 6 years of follow-up: the Pulling Through Study

BACKGROUND

There is a need to better describe and understand the prevalence of breast cancer treatment-related adverse effects amenable to physical therapy and rehabilitative exercise. Prior studies have been limited to single issues and lacked long-term follow-up. The Pulling Through Study provides data on prevalence of adverse effects in breast cancer survivors followed over 6 years.

METHODS

A population-based sample of Australian women (n = 287) diagnosed with invasive, unilateral breast cancer was followed for a median of 6.6 years and prospectively assessed for treatment-related complications at 6, 12, and 18 months and 6 years after diagnosis. Assessments included postsurgical complications, skin or tissue reaction to radiation therapy, upper-body symptoms, lymphedema, 10% weight gain, fatigue, and upper-quadrant function. The proportion of women with positive indication for each complication and 1 or more complication was estimated using all available data at each time point. Women were only considered to have a specific complication if they reported the highest 2 levels of the Likert scale for self-reported issues.

RESULTS

At 6 years after diagnosis, more than 60% of women experienced 1 or more side effects amenable to rehabilitative intervention. The proportion of women experiencing 3 or more side effects decreased throughout follow-up, whereas the proportion experiencing no side effects remained stable around 40% from 12 months to 6 years. Weight gain was the only complication to increase in prevalence over time.

CONCLUSIONS

These data support the development of a multidisciplinary prospective surveillance approach for the purposes of managing and treating adverse effects in breast cancer survivors.

The utility of screening for deep venous thrombosis in asymptomatic, non-ambulatory neurosurgical patients

OBJECTIVES

Decisions regarding deep venous thrombosis (DVT) prophylaxis are complicated in neurosurgical patients because of the potential for catastrophic bleeding complications. Screening with venous duplex ultrasound (VDUS) may improve outcomes, but can strain hospital resources. Since there is little data to guide VDUS surveillance, we investigated the utility of a comprehensive VDUS screening program in neurosurgical patients.

METHODS

Medical records of patients admitted to the neurosurgical service at a university-affiliated hospital from October 2007 through January 2010 who underwent weekly VDUS of the lower extremities until ambulatory or discharged were retrospectively reviewed. Demographics, comorbidities, interventions, and use of DVT prophylaxis were recorded. All patients in this study were asymptomatic for clinical evidence of DVT. When DVT was identified, VDUS reported its location and progression.

RESULTS

One hundred seventy-four consecutive patients were screened according to the established protocol. They had 312 VDUS studies, 68 (21.8%) of which were positive in 40 (23%) unique patients; 10 were bilateral and two catheter-related. There were no documented pulmonary emboli in this series. Seventeen patients (37.7%) had isolated calf DVT, four of which were bilateral (totaling 21 thrombi), and 9 (20%) had coexistent thrombi in calf and proximal veins. Of the 21 isolated calf DVTs, 15 had follow-up studies and two progressed to the popliteal or ileofemoral vein on follow-up (13.3%). Mechanical prophylaxis was uniformly utilized, but chemical prophylaxis varied based on surgeons' assessment of bleeding risk. DVT developed in 19.3% (28/145) of patients receiving prophylactic medication (unfractionated heparin or low-molecular weight heparin) and 41.4% (12/29) receiving no chemoprophylaxis (P < .001). The only patient characteristic that correlated with DVT risk was a body mass index <30 (9.1% vs 29.4%, P = .01).

CONCLUSIONS

Despite the uniform application of mechanical DVT prophylaxis and the use of chemoprophylaxis in a majority of patients, we found a 23% incidence of DVT in these hospitalized, nonambulatory, neurosurgical patients. No patients with isolated calf DVT had an embolic complication but 13.3% progressed proximally in short-term follow-up. While chemical prophylaxis significantly reduced DVT risk, no factor was sufficiently predictive to exclude patients from screening. These data substantiate the importance of full leg VDUS screening and maximizing DVT prophylaxis in this high risk population.

Anticoagulation risk in spine surgery

STUDY DESIGN

Systematic review.

OBJECTIVE

To determine the high-risk populations for thromboembolic events in spine surgery patients, the risk of anticoagulation in spine surgery patients by type of anticoagulation, and whether there is a safe perioperative window of nonanticoagulation for these high-risk patients.

SUMMARY OF BACKGROUND DATA

Thromboembolic complications after major spinal surgery is a significant risk for patients. Anticoagulation to reduce this risk is of concern because of the possibility of excessive bleeding or postoperative hematomas and associated neurologic deficits. There seems to be a paucity of literature on this topic.

METHODS

A systematic review of the English-language literature was undertaken for articles published between January 1990 and December 2008. Electronic databases and reference lists of key articles were searched to identify published studies examining coagulopathy in major spine surgery. Two independent reviewers assessed the strength of literature using the Grading of Recommendations Assessment, Development, and Evaluation criteria, assessing quality, quantity, and consistency of results. Disagreements were resolved by consensus.

RESULTS

A total of 93 articles were initially screened, and 29 ultimately met the predetermined inclusion criteria. The risk of thromboembolism in patients not receiving chemical prophylaxis was slightly higher in surgery to correct deformity (5.3%) and trauma patients (6.0%) than in surgery for degenerative conditions (2.3%). Fatal pulmonary embolism was rare. Bleeding complications occurred rarely with the use of anticoagulation; risk of major bleeding ranged from 0.0% to 4.3% across several types of anticoagulants. Postoperative hematoma was reported in only 10 of 2507 patients.

CONCLUSION

Venous thromboembolism is uncommon after elective spine surgery. Trauma patients are at increased risk, and chemical prophylaxis should be considered. The safe timing of the administration of anticoagulation agents is unknown.

The prevalence of and specific risk factors for venous thromboembolic disease following elective spine surgery

BACKGROUND

Venous thromboembolic disease, including deep venous thrombosis and pulmonary embolism, is a serious and potentially life-threatening complication following orthopaedic surgical procedures. We sought to investigate the prevalence of thromboembolism as well as the efficacy and complications of various prophylactic measures in a population of patients who had undergone elective spine surgery.

METHODS

A meta-analysis and univariate logistic regression were performed on selected studies to determine the prevalence of and risk factors for deep venous thrombosis and pulmonary embolism following elective spine surgery. Studies were included on the basis of the selection criteria (specifically, the inclusion of only patients undergoing spine surgery, or the treatment of patients undergoing spine surgery as an independent cohort; the use of an objective diagnostic modality for the diagnosis of deep venous thrombosis, including Doppler ultrasonography or venography; the use of an objective diagnostic modality for the diagnosis of pulmonary embolism, including computed tomography of the chest or a ventilation-perfusion scan; and a study population of more than thirty patients). Patients with a known spinal cord injury were excluded.

RESULTS

Fourteen studies (including a total of 4383 patients) met our selection criteria. On the basis of the meta-analysis, the prevalence of deep venous thrombosis was 1.09% (95% confidence interval, 0.54% to 1.64%) and the prevalence of pulmonary embolism was 0.06% (95% confidence interval, 0.01% to 0.12%) following elective spine surgery. The use of pharmacologic prophylaxis significantly reduced the prevalence of deep venous thrombosis relative to either mechanical prophylaxis (p = 0.047) or no prophylaxis (p < 0.01). One fatal pulmonary embolism was reported. An epidural hematoma requiring surgical evacuation was reported in eight of 2071 patients receiving pharmacologic prophylaxis; three of these patients had a permanent neurologic deficit.

CONCLUSIONS

The risk of deep venous thrombosis and pulmonary embolism is relatively low following elective spine surgery, particularly for patients who receive pharmacologic prophylaxis. Unfortunately, pharmacologic prophylaxis exposes patients to a greater risk of epidural hematoma. More evidence is needed prior to establishing a protocol for prophylaxis against venous thromboembolic disease in patients undergoing elective spine surgery. Future prospective studies should seek to define the safety of various prophylactic modalities and to identify specific subpopulations of patients who are at greater risk for venous thromboembolism.

Hemostatic and hemorrhagic problems in neurosurgical patients

BACKGROUND

Abnormalities of the hemostasis can lead to hemorrhage, and on the other hand to thrombosis. Intracranial neoplasms, complex surgical procedures, and head injury have a specific impact on coagulation and fibrinolysis. Moreover, the number of neurosurgical patients on medication (which interferes with platelet function and/or the coagulation systems) has increased over the past years.

METHOD

The objective of this review is to recall common hemostatic disorders in neurosurgical patients on the basis of the "new concept of hemostasis". Therefore the pertinent literature was searched to provide a structured and up to date manuscript about hemostasis in Neurosurgery.

FINDINGS

According to recent scientific publications abnormalities of the coagulation system are discussed. Pathophysiological background and the rational for specific (cost)-effective perioperative hemostatic therapy is provided.

CONCLUSIONS

Perturbations of hemostasis can be multifactorial and maybe encountered in the daily practice of neurosurgery. Early diagnosis and specific treatment is the prerequisite for successful treatment and good patients outcome.

Critically ill cancer patients are not consistently hypercoagulable after craniotomy

INTRODUCTION

Recent reports using thrombelastography have suggested that neurosurgical patients develop a hypercoagulable state in the postoperative period. Since venous thromboembolism is a potentially life threatening complication in these patients, we studied a similar population in our institution.

METHODS

We conducted a prospective pilot study to evaluate postoperative coagulation changes in critically ill cancer patients after craniotomy. Data collected included demographics, diagnoses, severity of illness, all hematological information (coagulation tests included conventional and TEG), therapies, and complications. Analysis included descriptive statistics, and multivariate regression analysis.

RESULTS

Eleven patients were included in the study. Mean age was 52 +/- 17 years, BMI 28 +/- 6.5, APACHE II and SOFA scores were 11.18 +/- 5.0 and 3.82 +/- 1.6 respectively. The Coagulation Index (CI), which is derived from the measured values of R, K, MA, and alpha angle was 1.22 +/- 3.5, R 4.2 +/- 1.6, K 2.0 +/- 2.1, MA 60.78 +/- 5.97, and alpha angle 66.88 +/- 14.9; while the Thrombodynamic Potential Index (TPI), which is derived from the measured values of K and MA only was 32.48 +/- 21. The CI correlated significantly with R, K, alpha angle, MA, TMA, TPI, PMA, E, A30 and A60 but not with the PTT, INR, or SOFA and APACHE II scores. One patient was hypocoagulable by CI and TPI values; in contrast, nine patients were hypercoagulable by TPI but only one by CI. There were no cases of VTE.

CONCLUSIONS

Hypercoagulability as defined by the CI was not a common finding in this study. Although the TPI indicated hypercoagulability in a large number of patients, we do not believe it is a good tool to assess the patient's clotting status or predictor of thrombosis because in contrast to the CI, it does not take into account the enzymatic portions of the clotting cascade. A larger TEG study is warranted to determine the clinical significance of these changes in this and other populations.

Medical management of brain tumor patients

Brain tumors can present challenging medical problems. Seizures, peritumoral edema, venous thromboembolism, fatigue, and cognitive dysfunction can complicate the treatment of patients who have primary or metastatic brain tumors. Effective medical management results in decreased morbidity and mortality and improved quality of life for affected patients.

Multivariable Predictors of Postoperative Venous Thromboembolic Events after General and Vascular Surgery: Results from the Patient Safety in Surgery Study

BACKGROUND

Venous thromboembolism (VTE) is a potentially preventable postoperative complication. Accurate risk prediction is an essential first step toward limiting serious, and sometimes fatal, postoperative VTE. We sought to develop and test a model to predict patients at high risk for postoperative VTE.

STUDY DESIGN

Data from the Patient Safety in Surgery (PSS) Study were used to develop and test a predictive model of VTE using multiple logistic regression analyses.

RESULTS

VTE occurred in 1,162 of 183,069 (0.63%) patients undergoing vascular and general surgical procedures. The 30-day mortality in patients who suffered a VTE was 11.19%. Fifteen variables independently associated with increased risk of VTE included patient factors (female gender, higher American Society of Anesthesiologists class, ventilator dependence, preoperative dyspnea, disseminated cancer, chemotherapy within 30 days, and > 4 U packed red blood cell transfusion in the 72 hours before operation), preoperative laboratory values (albumin < 3.5 mg/dL, bilirubin > 1.0 mg/dL, sodium > 145 mmol/L, and hematocrit < 38%), and operative characteristics (type of surgical procedure, emergency operation, work relative value units, and infected/contaminated wounds). These variables were used to develop a predictive model for postoperative VTE (c-index = 0.7647) and a risk score that can be used in the preoperative assessment of patients undergoing major operations.

CONCLUSIONS

Venous thromboembolic events after noncardiac operations are relatively infrequent but highly lethal. Important multivariable risk factors for VTE in this setting were identified in the large PSS database. The risk-prediction scoring system, developed by using the logistic regression odds ratios, helps to identify patients at risk for postoperative VTE and to institute appropriate perioperative prophylactic measures.

Incidence and distribution of lower extremity deep vein thrombosis in rehabilitation patients: implications for screening

Patients admitted to in-patient rehabilitation programs have an increased risk for developing deep venous thrombosis (DVT). However, the utility of screening for lower extremity DVT using duplex ultrasound in this high-risk population is not well characterized. The purpose of this study is to identify whether or not screening lower-extremity duplex exams are indicated in this high-risk population. Screening lower extremity duplex exams were performed on all patients admitted to the rehabilitation center at Mt. Sinai Hospital over a 3-year period. Charts were reviewed for patient age, gender, diagnosis, date of screening and follow-up duplex exams, presence and location of venous thrombosis at each duplex exam, history of anticoagulation, and medical DVT prophylaxis. The presence of DVT at screening, the location of DVT along the lower extremity, and the outcome of calf DVT were analyzed in terms of gender, underlying diagnosis, and history of DVT prophylaxis. Lower extremity DVT was detected in 34% of patients. Twenty-three percent of patients had isolated calf vein thrombosis. Men were more likely than women to have DVT. Calf DVTs progressed in 3% of patients over an average follow-up of 2 weeks. The presence of DVT, its location along the lower extremity, and the outcome of calf vein DVT had no significant relationship to underlying diagnosis or history of prophylaxis. Screening duplex exams to detect lower extremity DVT in rehabilitation patients is useful. Screening altered management in 26% of patients, prompting either anticoagulation or repeat duplex exam.

Efficacy of Pneumatic Compression Stocking Prophylaxis in the Prevention of Deep Venous Thrombosis and Pulmonary Embolism Following 139 Lumbar Laminectomies With Instrumented Fusions

OBJECTIVE

Low-dose heparin (LDH) regimens reduce the frequency of deep venous thrombosis (DVT) and pulmonary embolism (PE) in spinal surgery but pose a risk of postoperative hemorrhage threatening neurologic function. Pneumatic compression stocking (CS) could provide an alternative means of mechanical prophylaxis alone against DVT and PE and would possibly avoid its hemorrhagic complications.

METHODS

The efficacy of CS alone in preventing DVT and PE was evaluated in 139 patients undergoing multilevel lumbar laminectomies (average 3.8 levels) with instrumented fusions (average 1.4 levels). All patients received CS stocking prophylaxis intraoperatively and throughout the average 5-day postoperative course including following ambulation. Doppler screening for DVT was routinely performed 2 days postoperatively. Subsequent Doppler studies or computed tomography angiograms were selectively performed in symptomatic patients with potential DVT/PE.

RESULTS

Four (2.8%) patients developed DVT 2-6 days postoperatively and required inferior vena cava (IVC) filters. One of the four had a positive routine screening Doppler study performed the second postoperative day. Two developed DVT the fourth postoperative day. The fourth patient developed DVT 6 days postoperatively but 3 weeks later embolized around the IVC filter. This patient, the only one to develop a PE, tested positive for Factor V Leiden mutation (hypercoagulable syndrome) and remains on long-term warfarin.

CONCLUSIONS

Pneumatic compression stocking prophylaxis effectively reduced the incidence of DVT (2.8%) and PE (0.7%) in 139 patients undergoing multilevel lumbar laminectomies with instrumented fusions. These rates compared favorably with those reported in spinal series employing LDH prophylaxis.

A review of the risks and benefits of differing prophylaxis regimens for the treatment of deep venous thrombosis and pulmonary embolism in neurosurgery

BACKGROUND

Annually, 2 million people in the United States develop deep venous thrombosis (DVT), and nearly 100,000 sustain fatal pulmonary emboli. Prophylaxis against DVT/pulmonary embolism (PE) is a critical issue, and options include elastic stockings, intermittent pneumatic compression stockings, low-dose unfractionated heparin (5000 U every 8-12 hours), and low molecular-weight heparin (ie, enoxaparin and dalteparin). The risks and benefits associated with different prophylaxis regimens used in the prevention of DVT and PE in neurosurgical procedures were analyzed.

METHODS

Neurosurgical studies focusing on different methods of prophylaxis used for the prevention of DVT and PE were reviewed. The efficacy, risks, and benefits of varied treatment options were evaluated, with particular emphasis on minor and major hemorrhages occurring where heparin-based protocols were used.

RESULTS

In Flinn et al series (Arch Surg. 1996;131(5):472-80), the incidence of DVT was greater for cranial (7.7%) than spinal procedures (1.5%). Although intermittent pneumatic compression devices provided adequate reduction of DVT/PE in some cranial and combined cranial/spinal series, low-dose subcutaneous unfractionated heparin or low molecular-weight heparins further reduced the incidence, not always of DVT, but of PE (Br J Neurosurg 1995;9(2):159-63; J Intensive Care Med 2003;18(2):59-79). Nevertheless, low-dose heparin-based prophylaxis in cranial and spinal series risks minor and major postoperative hemorrhages: 2% to 4% in a cranial series, 3.4% minor and 3.4% major hemorrhages in a combined cranial/spinal series, and a 0.7% incidence of major/minor hemorrhages in a spinal series (J Neurosurg 2003;99(4):680-4; Neurosurgery 1986;18(4):440-5; Eur Spine J 2004;13(1):1-8; J Intensive Care Med 2003;18(2):59-79).

CONCLUSIONS

Although mechanical prophylaxis provided effective prophylaxis against DVT/PE in many series, the added efficacy of low-dose heparin regimens has to be weighed against risks of major postoperative hemorrhages and their neurological sequelae.

Intermittent pneumatic compression stocking prophylaxis against deep venous thrombosis in anterior cervical spinal surgery: a prospective efficacy study in 200 patients and literature review

STUDY DESIGN

Intermittent pneumatic compression stockings (IPC) alone were prospectively used to avoid deep venous thrombosis (DVT) and pulmonary embolism (PE) in 100 consecutive patients undergoing single-level anterior corpectomy/fusion (ACF) and in 100 patients having multilevel ACF/posterior fusion.

OBJECTIVES

To determine the optimal prophylaxis against DVT and PE for patients undergoing anterior cervical spinal surgery.

BACKGROUND DATA

Mini-heparin and low-dose heparin prophylaxis in neurosurgery poses a 2% to 4% risk of major postoperative hemorrhage with resultant neurologic sequelae.

METHODS

Prophylaxis consisted of IPC alone. Doppler studies of the lower extremities were routinely obtained 2 days after surgery. Single-level ACF (100 patients) addressed two-level disc disease, spondylostenosis, and ossification of the posterior longitudinal ligament (OPLL). One hundred patients undergoing multilevel ACF (3+ levels) with posterior fusion (C2-T1) exhibited OPLL/spondylostenosis.

RESULTS

One patient undergoing single-level ACF developed DVT/PE 6 days after surgery; she exhibited Factor V Leiden mutation (hypercoagulability syndrome). Although 7 patients undergoing circumferential surgery developed DVT 2 to 14 days following surgery (mean, 7.15 days), only two clots localized in the iliac veins resulted in PEs (days 10 and 14 after surgery).

CONCLUSIONS

IPCs were as effective for prophylaxis against DVT/PE for 100 patients undergoing single-level ACF and for 100 having circumferential procedures as existing therapies (mini-heparin and low-dose heparin), without the risk of hemorrhage. However, the 1% and 2% respective rates of PE were comparable to frequencies of PE encountered in other cranial/spinal series using mini-heparin and/or low-dose heparin regimens but avoided the 2% to 4% risk of major postoperative hemorrhage.

Optimisation de l’interrogatoire dans l’évaluation du risque de maladie thromboembolique veineuse : l’étude OPTIMEV

Venous thromboembolism (VTE) is a frequent disease and remains a major cause of mortality and morbidity among our patients. During the 20 past years, clinical description, diagnostic tools, and treatment have changed dramatically. Most published data describing risk factors for VTE no longer apply to the patients seen in daily practice. We present here the rationale, aims, and methodology of the OPTIMEV Study (OPTimisation de l'Interrogatoire pour la Maladie thromboEmbolique Veineuse).

RATIONALE

Risk factors for VTE are numerous, complex and interactions between them and their clinical importance is difficult to measure (table I). For example, odds ratios for VTE recurrence vary greatly across longitudinal studies. We searched the National Library of Medecine (PubMed) and the Amedeo website using the following keywords: "venous thromboembolism", "pulmonary embolism", "deep vein thrombosis", "risk factors". We selected 84 relevant articles published between 1972 and 2005. Based on this literature analysis, we identified the following major risk factors: VTE recurrence, surgery, cancer, immobilization, age, biological factors. For these factors, data are lacking and some questions are proposed.

OBJECTIVES

The broad objective of the study is to better evaluate clinical risk factors that fit today's practice against VTE. Specific aims are: 1) to determine whether risk factors are different between proximal and distal deep vein thrombosis (DVT); 2) to develop and prospectively validate a new prediction rule for outpatients. The primary hypothesis is that careful assessment of VTE recurrence, adequate surgical thromboprophylaxis, cancer staging, and varicose vein stratification according to the CEAP classification, is mandatory for accurate evaluation of thromboembolic disease risk.

METHODS

We conducted a multicenter, prospective, cohort study of 10000 patients. Enrollees are inpatients and outpatients presenting with a clinical suspicion of VTE in Emergency Departments and outpatient clinics in France. 4173 patients have been enrolled at this time (Figure 2). All eligible patients are enrolled during a selected period of time through different seasons. Data are collected by physicians in charge of the patients using an electronic case recording form. Collected data include baseline characteristics, risk factors, results of diagnostic investigations. Outcome measures obtained through telephone interview at 3 and 12 months include cancer diagnosis, VTE recurrence, haemorrhagic events, treatments, death. Univariate and multivariate analysis will be performed using multilevel logistic regression. The study organization is performed by the Centre d'Investigation Clinique de Grenoble and is sponsored by the French Society of Vascular Medicine. First results, to be published in 2006, will allow development of new prediction rules for VTE diagnosis.

Prophylaxis for Deep Venous Thrombosis in Craniotomy Patients: A Decision Analysis

OBJECTIVE:

We sought to determine the most efficient perioperative prophylactic strategy for deep venous thrombosis (DVT) in craniotomy patients by use of a decision analysis model.

METHODS:

We conducted a structured review of the relevant literature and compiled the reported incidences of DVT, pulmonary embolism, and postoperative intracranial hemorrhage (ICH) in craniotomy patients. We also obtained from the literature estimates of the likelihood and the impact of various outcomes of these complications. Data from 810 craniotomies performed at our own institution were also examined. The decision analytic model was then used to compare the effectiveness of pneumatic compression boots with pneumatic compression boots combined with either unfractionated or low-molecular-weight heparin. The model dealt with variability by using both sensitivity analysis and Monte Carlo simulation.

RESULTS:

As expected, the addition of heparin lowered the incidence of both DVT and pulmonary embolism, but at the cost of increasing ICH. Because the deleterious effects of ICH were so much greater than the benefits from heparinization, overall outcomes were best with mechanical prophylaxis alone. This was especially true for low-molecular-weight heparin, which is associated with a relatively high risk of ICH. Our own institutional data support the findings in the literature. Although the differences are modest, they reach statistical significance in the case of low-molecular-weight heparin.

CONCLUSION:

Using decision analytic modeling, we have shown that mechanical prophylaxis yields outcomes in craniotomy patients superior to those of either unfractionated or low-molecular-weight heparin.

Deep vein thrombosis and malignancy: a surgical oncologist's perspective

Oncology patients are at increased risk of developing deep vein thrombosis (DVT) and its potentially fatal sequel, pulmonary embolism. This is due to multiple factors, including the presence of the malignancy itself, comorbid factors and therapy-related interventions. Issues that are peculiar to venous thrombosis in the oncology setting are discussed, based on a MEDLINE search of the English literature. These include the need to screen for malignancy in idiopathic DVT, a high index of suspicion for venous thrombosis in the cancer patient, the use of vena cava filters, and the anti-neoplastic effects of heparin. Asian patients appear to have a lower incidence of DVT compared to Caucasians. A recommended regimen for prophylaxis of DVT must take into account the varying thrombosis risk associated with different malignancies. Cancer patients not undergoing abdominal, pelvic or orthopaedic surgery (e.g. mastectomy) should use elastic compression stockings and be mobilized early, whereas low-molecular-weight heparin should be given to those undergoing more major surgery. In advanced malignancy, treatment of DVT palliates symptoms. These patients may need long-term anticoagulation with warfarin.

Prevention of venous thromboembolism: the Seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy

This article discusses the prevention of venous thromboembolism (VTE) and is part of the Seventh American College of Chest Physicians Conference on Antithrombotic and Thrombolytic Therapy: Evidence-Based Guidelines. Grade 1 recommendations are strong and indicate that the benefits do, or do not, outweigh risks, burden, and costs. Grade 2 suggests that individual patients' values may lead to different choices (for a full understanding of the grading see Guyatt et al, CHEST 2004; 126:179S-187S). Among the key recommendations in this chapter are the following. We recommend against the use of aspirin alone as thromboprophylaxis for any patient group (Grade 1A). For moderate-risk general surgery patients, we recommend prophylaxis with low-dose unfractionated heparin (LDUH) (5,000 U bid) or low-molecular-weight heparin (LMWH) [< or = 3,400 U once daily] (both Grade 1A). For higher risk general surgery patients, we recommend thromboprophylaxis with LDUH (5,000 U tid) or LMWH (> 3,400 U daily) [both Grade 1A]. For high-risk general surgery patients with multiple risk factors, we recommend combining pharmacologic methods (LDUH three times daily or LMWH, > 3,400 U daily) with the use of graduated compression stockings and/or intermittent pneumatic compression devices (Grade 1C+). We recommend that thromboprophylaxis be used in all patients undergoing major gynecologic surgery (Grade 1A) or major, open urologic procedures, and we recommend prophylaxis with LDUH two times or three times daily (Grade 1A). For patients undergoing elective total hip or knee arthroplasty, we recommend one of the following three anticoagulant agents: LMWH, fondaparinux, or adjusted-dose vitamin K antagonist (VKA) [international normalized ratio (INR) target, 2.5; range, 2.0 to 3.0] (all Grade 1A). For patients undergoing hip fracture surgery (HFS), we recommend the routine use of fondaparinux (Grade 1A), LMWH (Grade 1C+), VKA (target INR, 2.5; range, 2.0 to 3.0) [Grade 2B], or LDUH (Grade 1B). We recommend that patients undergoing hip or knee arthroplasty, or HFS receive thromboprophylaxis for at least 10 days (Grade 1A). We recommend that all trauma patients with at least one risk factor for VTE receive thromboprophylaxis (Grade 1A). In acutely ill medical patients who have been admitted to the hospital with congestive heart failure or severe respiratory disease, or who are confined to bed and have one or more additional risk factors, we recommend prophylaxis with LDUH (Grade 1A) or LMWH (Grade 1A). We recommend, on admission to the intensive care unit, all patients be assessed for their risk of VTE. Accordingly, most patients should receive thromboprophylaxis (Grade 1A).

Prophylaxis for deep venous thrombosis in patients with craniotomies: a review

Deep venous thrombosis (DVT) remains a source of significant morbidity and mortality in patients who undergo craniotomy procedures. Despite several studies in which the safety and efficacy of various prophylactic strategies were examined, there is still no consensus among clinicians. In this paper the authors review the literature with regard to epidemiological and pathophysiological features, screening methods, and prophylactic measures for DVT.

A quarter of a century of neurosurgery: the value of a relational database to document trends in neurosurgical practice of a tertiary referral hospital

OBJECTIVE AND IMPORTANCE

Increasing interest in evidence-based medicine has created a demand for accurate and accessible information on activity and trends in clinical practice. A database of all neurosurgery admissions at a teaching hospital maintained by a scientist has been utilised to examine changes in practice and complications from 1977 to 2001.

METHODS

A relational database, set up in 1982, now contains an unbroken record of all neurosurgical admissions at Royal North Shore Hospital (RNSH) since 1976. It supplies information for morbidity and mortality meetings, research and administrative purposes. A total of 23,766 admissions from 1977 to 2001 were examined. Statistical analysis of trends in age, gender, length of stay (LOS), diagnostic mix, surgery rates and complications in admissions was based on diagnostic groupings.

RESULTS

Proportions of vascular admissions rose and of trauma admissions fell. Mean age increased significantly for tumour, trauma and spinal patients; geometric mean LOS declined significantly for tumour, spine, vascular, cranial nerve and peripheral nerve groups. Concurrently, inpatient death rate fell significantly for tumour and vascular patients. Deep vein thrombosis (DVT) rose significantly for trauma, vascular, tumour, spinal and infection patients; pulmonary embolism (PE) rose significantly for tumour, trauma and spinal patients. There was no significant change in wound infection rate at approximately 3.5% of all operated patients. Wound haematoma rates fell significantly from 4.0% to 2.9% while the rate of postoperative cerebrospinal fluid (CSF) leak rose significantly from 0.5% to 2.0% of all operated patients.

CONCLUSION

The value of the database is demonstrated by its ability to provide analysis which shows statistically significant changes over time. Declining death rate and LOS indicate improved efficiency in managing patients, but these are offset by rising rates of CSF leak, DVT and PE. Such rises reflect the changing patterns of casemix and surgery performed, and increasing financial pressures on hospital departments.

The Incidence of Thromboembolism in the Surgical Intensive Care Unit

The clinical diagnosis of deep venous thrombosis (DVT) is unreliable. Studies have been performed examining the utility of frequent duplex scans. However, these studies included patients outside of the intensive care unit. The incidence of venous thromboembolism and the effect of a less intense surveillance protocol was prospectively examined at a level-1 urban trauma center for a 6 month period. During the study period there were 726 admission to the surgical intensive care unit. Sequential compression devices (SCDs) were used for DVT prophylaxis in 93 per cent of the admissions. A total of 114 duplex scans were ordered: 42 per cent for surveillance and the rest for evaluation of a clinical indication. Twelve DVTs were discovered (11% overall DVT rate). No patient on subcutaneous heparin or low-molecular-weight heparin developed a DVT or pulmonary embolism (PE). Four patients suffered a PE; however, none were found to have a lower extremity DVT on duplex ultrasound and all received SCD prophylaxis. Overall, proper use of DVT prophylaxis for intensive care unit days 1–14 was 77 per cent. The incidence of venous thromboembolism in a group of patients at overall high risk was low. A program of DVT surveillance with duplex ultrasound was not cost-effective.

Perioperative deep vein thrombosis in Chinese patients undergoing craniotomy

BACKGROUND

We attempted to determine the incidence of perioperative deep vein thrombosis (DVT) in Chinese patients undergoing elective craniotomy for brain tumors and to assess the efficacy of clinical and serial calf circumference assessment in detecting DVT.

METHODS

Between June 1999 and February 2001, 100 consecutive patients who underwent elective craniotomy for brain tumors at the Department of Neurosurgery, University of Hong Kong Medical Centre were examined for perioperative DVT. The demographic data, Glasgow coma score (GCS), mobility status, and the operative details were recorded. Graduated compression stockings and intermittent pneumatic compression were applied perioperatively as prophylaxis against DVT. Serial duplex scans were performed before and after operation. Clinical examination was also performed daily to look for signs of DVT. The calf circumference was measured at fixed levels for both limbs before each duplex scan surveillance.

RESULTS

The study group consisted of 44 males and 56 females, with a mean age of 54 +/- 15 years (range, 20-81 years). There was no preoperative DVT. Postoperative DVT was detected on duplex scan in four patients (4%), two of whom had bilateral involvement. The thrombosis was confined to the calf veins in two limbs. The demographic data, neurologic status and operative details of patients with and without DVT were similar. Patients with DVT had no clinically recognizable signs. The change in calf circumference measurement was also not predictive of DVT.

CONCLUSIONS

The incidence of perioperative DVT in Chinese patients undergoing elective craniotomy for brain tumors appears to be low with the present mechanical prophylactic measures. Given the low incidence of proximal DVT as detected by duplex scan, the use of heparin prophylaxis may not be justified because of the increased risk of intracranial bleeding. Clinical assessment with calf circumference measurement is unreliable in the diagnosis of DVT.

Perioperative assessment of coagulability in neurosurgical patients using thromboelastography

BACKGROUND

Thrombelastography is a useful technique for evaluating coagulability. We hypothesized that it could be used to determine postoperative hematologic complications during and after neurologic surgery.

METHODS

Forty-six neurosurgical patients were stratified by diagnosis: subarachnoid hemorrhage from ruptured intracranially aneurysms, intracranial-axial lesions, intracranial-extra-axial lesions, and degenerative spine disease. Thromboelastograms were performed before, during, and after surgery. Hematologic data were collected preoperatively and postoperatively; computed tomography scans and lower extremity Doppler sonography were performed postoperatively. A thrombosis index (TI) was used to assess coagulability.

RESULTS

Coagulability increased over the course of surgery for all patients (p < 0.0001). In craniotomy patients, coagulability increased over the course of surgery (p < 0.05) with the most dramatic increase from intubation to skin incision (p < 0.05), and then after tumor removal or aneurysm clipping (p < 0.10). Univariate analysis among craniotomy patients showed that female gender (p < 0.0004) and smoking (p < 0.06) were associated with hypercoagulability. Among craniotomy patients, younger age was associated with hypercoagulability in the preoperative period (p < 0.01). There was no significant association between coagulability and aspirin or NSAID use, or intraoperative fluid volume. No patient developed a postoperative hematoma and one patient (2.2%) developed a lower extremity deep vein thrombosis.

CONCLUSIONS

Increased coagulability begins between induction of anesthesia and skin incision, and continues to increase throughout surgery. These changes are more pronounced in patients undergoing craniotomy compared to patients undergoing spine procedures.

Ultrasound and other imaging technologies in the intensive care unit

As technology advances, more imaging and procedures are performed at the bedside on critically ill patients in ICUs, thereby eliminating the risks of transporting patients. These imaging techniques can serve as diagnostic and therapeutic tools in treating the acute and chronic consequences of injured, critically ill patients. One area of growth is ultrasonography. Critical care applications of ultrasonography are expanding, and the learning curve of surgeons and intensivists performing some of these studies is improving. Ultrasonography can supplement physical examination and provide useful "real-time" information on nearly every body cavity. Other imaging technology is also available in a portable form, enabling imaging directly at the bedside. Images are now becoming readily and easily available with the advancement of teleradiology. Some of the imaging modalities are still in development, and their clinical effectiveness is being studied. In the future, more uses of these various imaging technologies may become evident and cost-effective.

Duplex ultrasound insertion of inferior vena cava filters in multitrauma patients

BACKGROUND

Techniques for placement of inferior vena cava (IVC) filters have undergone continued evolution from open surgical exposure of the venous insertion site to percutaneous insertion in most cases today. However, the required transport either to an operating room or interventional suite can be complex and potentially hazardous for the multiply injured trauma patient who may require ventilator support, controlled intravenous infusions, or skeletal immobilization. Increased experience with color-flow duplex scanning for routine IVC imaging and portability of ultrasound equipment have suggested the usefulness of duplex-guided IVC filter insertion (DGFI) in critically ill trauma and intensive care unit (ICU) patients.

METHODS

A total of 25 multitrauma/ICU patients were considered for DGIF. Screening color-flow duplex scans were performed on all patients, and obesity or bowel gas prevented ultrasound imaging in 2 cases, leaving 23 patients suitable for DGFI. In each case, the IVC was imaged in the transverse and longitudinal planes. The right renal artery was identified as it passed posterior to the IVC and was used as a landmark of the infrarenal segment of the IVC. All procedures were performed at the bedside in a monitored ICU setting using percutaneous placement of titanium Greenfield filters. Duplex scanning after insertion was used to document proper placement, and circumferential engagement of the filter struts in the IVC wall. An abdominal radiograph was also obtained in each case to confirm proper filter location. Duplex ultrasound imaging was repeated within 1 week of insertion to assess IVC and insertion site patency.

RESULTS

DGFI was successful in all cases. The filter was deployed at a suprarenal level in one case, as was recognized at the time of postprocedural scanning. Three patients died as a result of their injuries but there were no pulmonary embolism deaths. Repeat duplex scanning was obtained in 17 patients, and revealed no case of IVC or insertion site thrombosis.

CONCLUSIONS

Vena caval interruption can be safely performed under ultrasound guidance in a monitored, ICU environment. In selected multiply injured trauma patients, this will reduce the risk, complexity and cost of transport for these critically ill patients. DGFI also reduces procedural costs compared with an operating room or interventional suite, and eliminates intravenous contrast exposure. Preprocedural scanning is essential to identify patients suitable for DGFI, and careful attention must be paid to the known ultrasonographic anatomical landmarks.

Venous thromboembolism in trauma patients: standardized risk factors

PURPOSE

This study was done to evaluate the use of published standardized risk factors for venous thromboembolism (VTE) in patients admitted to a trauma intensive care unit (ICU) and to derive guidelines for the use of low molecular weight heparin (LMWH) and surveillance venous Doppler ultrasound scanning (VDUS).

METHODS

Patients were admitted to a regional trauma center ICU. Two periods were studied. Period 1 was a retrospective analysis of documented cases of VTE in the trauma registry from 1993 to 1995 (n=39). The period was also a review of all patients admitted to a trauma ICU in 1994 without VTE who met the following criteria: age greater than 11 years, ICU stay of more than 36 hours, and survival of more than 72 hours (n=227). Period 2 was a concurrent analysis of 1996 documented cases of VTE and similarly selected ICU admissions (VTE, n=10; no VTE, n=224). Risk factor scores (R1, admitting; R2, total) were calculated from the International Society for Cardiovascular Surgery/Society for Vascular Surgery reporting standards. The scores were cumulative by category and over time. The suitability of such standards was determined in period 1. The resulting therapeutic and surveillance guidelines were evaluated in period 2.

RESULTS

Period 1 risk factor scores, R1 and R2, were correlated with the occurrence of VTE from chi2 test (P < .05 and P < .01, respectively). Risk categories were grouped as low, moderate, and high. VTE was not observed in the low-risk group (0 to 2). Among all VTE (n=49), 11 cases occurred in patients with moderate-risk scores and 38 in patients with high-risk scores. In 1994 and 1996, the selected groups were analyzed and the incidence rate of VTE was 4.7% in both years for the moderate-risk group and 2.5% and 4.8% for the high-risk group, respectively. Most VTE cases (78%) received some form of prophylaxis (PRx), and 26% of cases had multiple methods of prophylaxis (MPRx). This included 80% of the cases that received unfractionated heparin. In period 2, no pulmonary emboli (PE) occurred, in contrast to period 1, in which 16 of 39 cases of VTE (41%) were first seen with PE. In period 2, no patient receiving MPRx, including compression and LMWH, had VTE develop. Surveillance VDUS discovered 60% of 1996 cases in period 2. No PE were seen in period 2.

CONCLUSION

Standard risk factors were easily applied to the trauma patient at the bedside. Patients at low risk needed no PRx. Patients at high risk did best with both compression devices and LMWH. VDUS was recommended selectively in patients at high risk in whom multiple-method PRx could not be achieved. Patients at moderate risk required further study to define optimal PRx and need for surveillance VDUS. Intracaval devices were used prophylactically only twice.