Use of enoxaparin for VTE prophylaxis in patients post neurosurgery Lily Lin Surgery Rotation October 16 th , 2019 Preceptor: Carly Hoffman 1
Learning Objectives • List 3 risk factors for VTE in patients post neurosurgery • List 4 viable alternatives and regimens for VTE prophylaxis in neurosurgery patients • Determine the appropriate length of time between surgery and initiation of chemical VTE prophylaxis in select high risk patients • Select an appropriate regimen and monitoring plan for a patient post neurosurgery for aneurysmal subarachnoid hemorrhage (aSAH) 2
Patient: TN ID 56 y/o F, 70kg CC Headache and confusion HPI Onset of headaches at ~4pm on September 8 th , presented to ED at PM Medical History Medications Prior to Admission Type II diabetes mellitus Metformin 250mg po TID (A1C 7.5 March 2019) Hypertension Hydrochlorothiazide 25mg po daily Perindopril 8mg po daily Nifedipine ER 90mg po daily Atenlolol 12.5mg po daily Dyslipidemia Rosuvastatin 5mg po daily NKDA, unremarkable social and family Hx 3
Course in Hospital Course in Hospital: • Sept 8: CT in ED showed subarachnoid hemorrhage of left middle cerebral artery (MCA) aneurysm (aSAH) • Deterioration post CT, intubated • Sept 8: Repeat CT showed worsening rebleed à external ventricular drain inserted, admitted to Neurosurgery • Sept 9: Left frontal craniotomy and MCA clipping à ICU • Sept 18: Vasospasm requiring intra-arterial verapamil • Sept 23: Tracheostomy and PEG inserted • Sept 30: Worsening hydrocephalus à ventriculoperitoneal shunt inserted, step down to NICU 4
Review of Systems (Oct 4 - POD #23, post-EVD removal day #4) Vitals T 37.4, BP 190/87 , HR 82 regular, RR 24, O2 Sat 99% (0.28 Trach Mask) CNS PEARL, extraocular movements full, face midline, non-verbal, no pronator drift, no tremor, obeys L hand and L leg with weak R leg, GCS 7 CVS N S1/S2, no edema, no elevated JVP. ECG Sept 9 QTc 515ms RESP Equal air entry bilaterally Tracheostomy GI Abdomen soft, non-tender. AST 44, ALT 67, GGT 138, AP 102 Renal SCr 48, CrCl 105, BUN 5.0 Endocrine Gluc checks q6h Heme WBC 9.5, RBC 3.10, Hgb 93 , MCV 95 Lytes/Fluids Na 139, K 3.9, Cl 107, PO4 1.22, Mg 0.84 5
Review of Systems Continued Cultures CSF from EVD (Sept 30): no growth x 4 days Blood Culture x 2 (Sept 25): no growth x 5 days (final) Respiratory culture from Trach (Sept 27): no growth Diagnostics CXR Sept 11: unremarkable EEG Sept 14: unremarkable CTA Sept 28: no new hemorrhage, interval progression of hydrocephalus, no evidence severe vasospasm Lines/Drains PICC line, PEG tube Feeds Isosource 1.5, 45 mL/hour (continuous via PEG) DVT Sequential compression device prophylaxis Mobility Not mobilizing 6
Medical Problems Medications In Hospital aSAH Nimodipine 60mg po q4h x 21 days Hypertension Hydralazine 10-20 mg IV q15 min PRN Labetalol 5-10mg IV q10 min PRN (SBP target < 220) Seizure Prophylaxis Levetiracetam 500mg po BID Diabetes Insulin regular sliding scale Pain Tylenol 325-650g po/ng q4h PRN Constipation Neurosciences Bowel Protocol 7
DTP’s 1. Patient is at risk of experiencing complications of hypertension secondary to inadequate therapy and requires reassessment 2. Patient is at risk of experiencing venous thromboembolism secondary to inadequate therapy and requires reassessment 3. Patient is at risk of experiencing adverse effects of levetiracetam secondary to unnecessary therapy and requires reassessment 4. Patient is at risk of experiencing continued uncontrolled blood glucose levels and requires reassessment of therapy 8
VTE Risk in Neurosurgery Patients • Deep vein thrombosis (DVT) rate as high as 34% - cause of pulmonary embolism in approx. 36-45% of cases • Risk factors: duration of surgery, age, coagulopathy, malignancy, altered mental status, prolonged bed rest • Distinct aSAH risk factors: male sex, black ethnicity • aSAH: highest risk for DVT post rupture is between days 5 to 9 Neurosurg Clin N Am 29 (2018) 567–574 Journal of Clinical Neuroscience 21 (2014) 282–286 J Neurosurg . 2015 October ; 123(4): 891–896. 9
Current Guidelines and Practices • Critical Care Guidelines for aSAH (2011) – Sequential compression devices (SCD’s) upon admission - chemoprophylaxis withheld 24h before and after procedures – Duration uncertain, may be based on patient mobility • Chest (2012) – Add pharmacologic to mechanical prophylaxis in high risk patients • European Society of Anesthesiology (2018) – Delay initiation of UFH or LWMH until at least 24h after surgery (when there is evidence of hemostasis à post-op CT scan) – In high risk patients: SCD’s pre-op with addition of LMWH/UFH post- op – Continue until discharge Neurocrit Care (2011) 15:211–240 Chest. 2012 Feb;141(2 Suppl):e227S-e277S. Eur J Anaesthesiol 2018; 35:90–95 10
Current Guidelines and Practices • Recent meta-analysis (2018) comparing chemoprophylaxis vs. mechanical prophylaxis or placebo showed significant benefit to chemoprophylaxis (OR 0.51, 95% CI 0.37-0.71, NNT = 11) • At VGH NSx: start considering chemoprophylaxis after POD #5 – Limiting factors: potential expansion of intracranial hemorrhage J Neurosurg. 2018 Oct;129(4):906-915. 11
Proposed Alternatives 1. Dalteparin 5000 units SC daily 2. Enoxparin 40mg SC daily – Recently replaced DALT for both prophylaxis and treatment of VTE in VCH (PPO’s updated) – Team reluctant to start ENOX, prefers DALT 3. Heparin 5000 units SC BID – Shown to be as effective as LMWH, used predominantly in earlier trials 4. Sequential compression devices alone 12
Goals of Therapy 1. Reduce risk of VTE (DVT/PE) and associated risk of mortality 2. Prevent hematoma expansion and hemorrhagic events secondary to anticoagulation use 3. Minimize adverse drug reactions secondary to anticoagulation use 4. Facilitate ease of administration with anticoagulation therapy 5. Maintain or improve quality of life 13
Clinical Question In patients post surgery for aSAH, how does enoxaparin compare to other interventions for VTE prophylaxis relative to efficacy and safety parameters? P Patients post neurosurgery for aSAH (clipping, coiling, craniotomy) I Enoxaparin C LWMH, UFH or mechanical prophylaxis O Efficacy – Symptomatic, objectively documented VTE (DVT or PE) Safety – Major bleeding requiring withdrawal of txt (decrease in Hgb level of at least 2g/dL, transfusion of 2 or more units pRBC), fatal bleeding, expansion of hematoma 14
Literature Search Pubmed (n=89) (((enoxaparin) AND (craniotomy OR neurosurgery OR subarachnoid hemorrhage) AND (dalteparin OR low molecular weight heparin OR heparin))) OVID EMBASE (n=143) [enoxaparin.mp AND (craniotomy.mp OR neurosurgery.mp OR aneurysmal subarachnoid hemorrhage.mp) AND (dalteparin.mp OR low molecular weight heparin.mp OR unfractionated heparin.mp] Cochrane RCT (n=7) [enoxaparin.mp AND (craniotomy.mp OR neurosurgery.mp) AND (dalteparin.mp OR low molecular weight heparin.mp OR heparin.mp] Results specific to 4 Systematic Reviews (1 highlighted above) PICO 4 RCT’s (2 highlighted) 2 Retrospective analyses (1 highlighted) 15
Dudley (2010) Early Venous Thromboembolic Event Prophylaxis in Traumatic Brain Injury Retrospective chart review P (n=287) Moderate to severe TBI Baseline characteristics: mean age 46.5, average GCS score 7.4, 75% M, >50% underwent surgery I Enoxaparin 30mg BID SC 48-72h post trauma C Dalteparin 5000 IU SC 48-72h post trauma O 1. % patients dx with VTE 2. % of patients dx with symptomatic expansion of pre-existing ICH 3. Differences between ENOX and DALT Results: No significant difference in VTE rates between groups (7% in ENOX, 7.5% • DALT, p=0.868) • 1 patient in ENOX group suffered fatal ICH expansion Author’s Conclusion : LMWH is safe after ICH stability, no difference in VTE rates between ENOX and DALT JOURNAL OF NEUROTRAUMA 27:2165–2172 16
Critical Appraisal Strengths Uniformed dosing Limitations Baseline characteristics unbalanced (more DALT • patients severely injured, lower GCS scores) CT scans performed only when clinically indicated • Bleeding at other sites not documented • Outcomes of surgical patients not documented • Length of prophylaxis not documented • My conclusion Not entirely applicable to patient (TBI patients, ? • surgery outcomes) TBI specific risk factors: higher index severity score, low • extremity fracture Given high VTE risk in both TBI and aSAH population, • warrants extrapolation to our patient 17
Siironen (2003) No effect of enoxaparin on outcome of aSAH Randomized, double blind, single centre trial P (n=170) Patients with aneurysmal SAH Baseline characteristics: ~45% M, average age 49 with co-morbidities e.g HTN, smoking I Enoxaparin 40mg SC daily 24-48h post-surgery x 10 days C Placebo 24-48h post-surgery x 10 days O GCS and mRS at 3 months Results : • No significant differences in mRS between groups (p=0.062) 4/85 patients in placebo group experienced VTE (1 fatal PE at 5 weeks) • vs. 1/85 in ENOX group (at 4 weeks) 4/85 patients experienced intracranial bleeding in ENOX group – no • treatment required (2 asymptomatic) Author’s conclusion : No effect on outcome of aSAH, but ENOX could be helpful for VTE prevention in poor-grade patients with prolonged bed rest J Neurosurg. 2003 Dec;99(6):953-9. 18
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