Analysis of venous thromboembolism in neurosurgical patients undergoing standard versus routine ultrasonography

Thromboembolic prophylaxis in neurosurgical practice: a systematic review

BACKGROUND

In neurosurgical patients, the risk of developing venous thromboembolism (VTE) is high due to the relatively long duration of surgical interventions, usually long immobilization time after surgery, and possible neurological deficits which can negatively influence mobility. In neurosurgical clinical practice, there is lack of consensus on optimal prophylaxis against VTE, mechanical or pharmacological.

OBJECTIVE

To systematically review available literature on the incidence of VTE in neurosurgical interventions and to establish an optimum prevention strategy.

METHODS

A literature search was performed in PubMed, Embase, Web of Science, Cochrane Library, and EmCare, based on a sensitive search string combination. Studies were selected by predefined selection criteria, and risk of bias was assessed by Newcastle-Ottawa Quality Assessment Scale and Cochrane risk of bias.

RESULTS

Twenty-five studies were included, half of which had low risk of bias (21 case series, 3 comparative studies, 1 RCT). VTE was substantially higher if the evaluation was done by duplex ultrasound (DUS), or another systematic screening method, in comparison to clinical evaluation (clin). Without prophylaxis DVT, incidence varied from 4 (clin) to 10% (DUS), studies providing low molecular weight heparin (LMWH) reported an incidence of 2 (clin) to 31% (DUS), providing LMWH and compression stockings (CS) reported an incidence of 6.4% (clin) to 29.8% (DUS), and providing LMWH and intermittent pneumatic compression devices (IPC) reported an incidence of 3 (clin) to 22.3% (DUS). Due to a lack of data, VTE incidence could not meaningfully be compared between patients with intracranial and spine surgery. The reported incidence of pulmonary embolism (PE) was 0 to 7.9%.

CONCLUSION

Low molecular weight heparin, compression stockings, and intermittent pneumatic compression devices were all evaluated to give reduction in VTE, but data were too widely varying to establish an optimum prevention strategy. Systematic screening for DVT reveals much higher incidence percentages in comparison to screening solely on clinical grounds and is recommended in follow-up of neurosurgical procedures with an increased risk for DVT development in order to prevent occurrence of PE.

Unfractionated heparin versus enoxaparin for venous thromboembolism prophylaxis in intensive care units: a propensity score adjusted analysis

Venous thromboembolism (VTE) is a common complication in hospitalized patients. Pharmacologic prophylaxis is used in order to reduce the risk of VTE events. The main purpose of this study is to compare the prevalence of deep vein thrombosis (DVT) and pulmonary embolism (PE) in patients admitted to the intensive care unit (ICU) who received unfractionated heparin (UFH) versus enoxaparin as VTE prophylaxis. Mortality was evaluated as a secondary outcome. This was a Propensity Score Adjusted Analysis. Patients admitted to neurology, surgical, or medical ICUs and screened with venous doppler ultrasonography or computed tomography angiography for detection of VTE were included in the analysis. We identified 2228 patients in the cohort, 1836 (82.4%) patients received UFH and 392 (17.6%) patients received enoxaparin. Propensity score matching yielded a well-balanced cohort of 950 (74% UFH, 26% enoxaparin) patients. After matching, there was no difference in prevalence of DVT (RR 1.05; 95% CI 0.67-1.64, p = 0.85) and PE (RR 0.76; 95% CI, 0.44-1.30, p = 0.31). No significant differences in location and severity of DVT and PE between the two groups were detected. Hospital and intensive care unit stay was similar between the two groups. Unfractionated heparin was associated with a higher rate of mortality, (HR 2.04; 95% CI, 1.13-3.70; p = 0.019). The use of UFH as VTE prophylaxis in ICU patients was associated with a similar prevalence of DVT and PE compared with enoxaparin, and the site and degree of occlusion were similar. However, a higher mortality rate was seen in the UFH group.

Venous Thromboembolism Prophylaxis in Elective Neurosurgery: A Survey of Board-Certified Neurosurgeons in the United States and Updated Literature Review

BACKGROUND

Venous thromboembolism (VTE) remains the single most important preventable cause of morbidity and mortality following neurosurgical procedures, with an incidence of approximately 16%. In the absence of stringent guidelines, the variation in current practice patterns could be considerable and was the underlying basis for this study.

OBJECTIVES

Our objective is to evaluate the modality of thromboprophylaxis used by neurosurgeons.

METHODS

In line with "CHERRIES" (Checklist for Reporting Results of Internet E-Surveys) guidelines, an online survey regarding postoperative VTE prophylaxis following elective neurosurgical procedures was created using Google Forms and distributed to 1500 board-certified neurosurgeons in the United States.

RESULTS

A total of 370 board-certified neurosurgeons (24.7%) responded to the survey. Sequential compression device was the only primary method of thromboprophylaxis used by 27.2% and 26.5% of respondents after elective craniotomy for tumor resection and spine surgery, respectively. Of the chemical prophylaxis, subcutaneous heparin 5000 U every 8 hours was the most commonly used medication followed by enoxaparin 40 mg daily. Most responders were comfortable starting chemical prophylaxis on postoperative day 1, followed by day 2 and day 3 in both types of surgeries. The mean postoperative time of chemical prophylaxis initiation was significantly more delayed by respondents with longer years in practice.

CONCLUSIONS

This study highlights the variation in practice between neurosurgeons in managing postoperative VTE prophylaxis after elective spine and cranial surgeries. In lieu of this variation, our results showed that most neurosurgeons are comfortable starting chemical prophylaxis as soon as postoperative day 1 following both types of procedures.

Surveillance or no surveillance ultrasonography for deep vein thrombosis and outcomes of critically ill patients: a pre-planned sub-study of the PREVENT trial

PURPOSE

We examined the association between surveillance for deep vein thrombosis (DVT) among medical-surgical critically ill patients by twice-weekly ultrasonography and 90-day all-cause mortality.

METHODS

This was a pre-planned sub-study of the Pneumatic Compression for Preventing Venous Thromboembolism (PREVENT) trial (Clinicaltrials.gov: NCT02040103) that compared addition of intermittent pneumatic compression (IPC) to pharmacologic prophylaxis versus pharmacologic prophylaxis alone. The surveillance group included enrolled patients in the trial, while the non-surveillance group included eligible non-enrolled patients. Using logistic regression and Cox proportional hazards models, we examined the association of surveillance with the primary outcome of 90-day mortality. Secondary outcomes were DVT and pulmonary embolism (PE).

RESULTS

The surveillance group consisted of 1682 patients and the non-surveillance group included 383 patients. Using Cox proportional hazards model with bootstrapping, surveillance was associated with a decrease in 90-day mortality (adjusted HR 0.75; 95% CI 0.57, 0.98). Surveillance was associated with earlier diagnosis of DVT [(median 4 days (IQR 2, 10) vs. 20 days (IQR 16, 22)] and PE [median 4 days (IQR 2.5, 5) vs. 7.5 days (IQR 6.1, 28.9)]. There was an increase in diagnosis of DVT (adjusted HR 5.49; 95% CI 2.92, 13.02) with no change in frequency in diagnosis of PE (adjusted HR 0.56; 95% CI 0.19, 1.91).

CONCLUSIONS

Twice-weekly surveillance ultrasonography was associated with an increase in DVT detection, reduction in diagnostic testing for non-lower limb DVT and PE, earlier diagnosis of DVT and PE, and lower 90-day mortality.

TRIAL REGISTRATION

The PREVENT trial is registered at ClinicalTrials.gov, ID: NCT02040103. Registered on 3 November 2013; Current controlled trials, ID: ISRCTN44653506. Registered on 30 October 2013.