Deep Vein Thrombosis and Pulmonary Embolism prophylaxis in Asian general surgical patients: is it necessary?

AMY KOK

Caritas Medical Centre

Introduction

Importance Incidence Current practice and guidelines Review of prophylactic methods Applicable to our patients?

Introduction

General surgical patients Fatal PE ~1% DVT ~24%

10% hospital deaths attributed to PE

Venous thromboemobolism (VTE): A Major Source of Mortality and Morbidity

Consequence of unprevented DVT Calf (46%)/thigh (67%)/pelvis(77%) Calf (46%)/thigh (67%)/pelvis(77%) PE PE

50% untreated DVT PE 50-80% untreated PE associated with

DVT

Clinicopathological pattern of PTE in Chinese autopsy patient:comparison with caucasian series Pathology 1997

Literature review –prophylaxis works! New England Journal of Medicine

1988 and 1999

Prophylaxis can reduce: PE by 50% DVT by 2/3 No increase in bleeding Long term mortality reduction

VTE: The most common preventable cause of hospital death

Incidence in Caucasian

USA 100 per 100,000

UK 48 per 100,000 DVT 23 per 100,000 PE (12% mortality)

Australia 30,000 new cases 2,000 death per year

3rd most common vascular disorder

Incidence in Asia

Study shows that incidence of 1st time VTE of Asian 3-5x lower

HOWEVER…

Incidence in Asia is increasing Hong Kong

16.6 per 100,000 population 3 per 10,000 hospital admissions 4.7%1.8% (PE death) (91-97)

Asia 17.1 per 100,000 DVT 3.9 per 100,000 PE Japan and Singapore: 2x increase in DVT

(9197)

Epidemiology of VTE in a Chinese population Br J Surg 2004;91:424-8

Pulmonary thromboembolism and venous thrombosis in the Chinese Clin Ortho 1980;150:253-60

Guidelines for VTE Prophylaxis

Modalities of prophylaxis

Mechanical Graduated

compression stockings

Intermittent pneumatic compression

Venous foot pump

Pharmacological Unfractionated

heparin Low-molecular

weight heparin Pentasaccharide Aspirin

Mechanical prophylaxis

Graduated compression stockings (GCS) Intermittent pneumatic compression

(IPC) devices Venous foot pump (VFP)

Aim: Increase venous outflow Reduce stasis within leg veins

Mechanical prophylaxis

Recommendation: High risk for bleeding (Grade 1A) Adjunct to anticoagulant prophylaxis

(Grade 2A) Proper use of and optimal adherence

(Grade 1A)Data from Geerts WH, Bergqvist, Pineo G, et al. Prevention of venous thromboembolism. Chest 2008; 133:381S-435S

Aspirin

NO significant benefit Inferior results

NOT recommended alone for VTE in any patient group (Group 1A)

Unfractionated heparin

Effective: General and orthopedics surgery Reduce VTE by 50-70%

Minor bleeding events: 6.3% vs 4.1% (statistically significant)

Low molecular weight heparin Examples:

Enoxaparin Fraxiparin

Effective: General and Orthopedic surgery

General surgery

General recommendation: Avoid dehydration Early mobilization Leg elevation Stop Oral contraceptive pills or Hormone

replacement therapy 4 weeks beforehand Consider regional anaesthesia

General surgery

Low Risk (Grade 1A) Minor Surgery

< 40 No additional risk factors (cancer, history of

VTE) Recommendation

No specific prophylaxis; early mobilization8th ACCP GUIDELINE

General surgery

Moderate Risk (Grade 1A) Minor Surgery:

with additional risk factors Nonmajor surgery:

40-60 years with no risk factors Major surgery:

< 40 with no risk factors

Recommendation Heparin (5,000 units Q12H, start 1-2 hrs preop till

discharge) Enoxaparin (40mg sc 1-12 hrs preop followed by

40mg sc Q24H 12hrs postop till discharge)8th ACCP GUIDELINE

General surgery

High Risk (Grade 1A) Non-major surgery:

> 60 yr or have additional risk factors Major Surgery:

> 40 or have additional risk factors

Recommendation Heparin (5,000 units Q8H, start 1-2 hrs preop till

discharge) Enoxaparin (40mg sc 1-12 hrs preop followed by

40mg sc Q24H 12hrs postop till discharge)

8th ACCP GUIDELINE

General surgery

Highest Risk (Grade 1C) Major surgery:

>40 + prior VTE, cancer or hypercoagulable state

Recommendation Heparin or LMWH

+ Intermittent pneumatic compression

sleeves till discharge8th ACCP GUIDELINE

Special consideration

Extended VTE prophylaxis (selected high risks patients) Recommendation

Extend prophylaxis for 28-30days (Grade 2A) Enoxaparin 40mg sc Q24H

High bleeding risk Recommendation

Optimal use of mechanical thromboprophylaxis (Grade 1A)

Subsituted or added on pharmacological thromboprophylaxis when bleeding risks decreased (Grade IC)

Prolonged prophylaxis in abdominal and pelvic cancer reduced DVT 12 to 5% Bergqvist NEJM 2002

General Surgery

Laparoscopic surgery Longer general anasthesia Pneumoperitoneum and reverse

Trendelenburg position reduces venous return

Laparoscopic surgery

Rates of VTE is LOW

General Surgery

Laparoscopic surgery Recommendation

No risk factors – aggressive early mobilization (Grade1A)

Risk factors – Heparin, LMWH, IPC or GCS (Grade 1C)

8th ACCP GUIDELINE

Bariatric Surgery

Reported incidence: varied! Unknown: optimal regimen, dosage, timing

and duration Recommendation

Routine thromboprophylaxis with Heparin, LMWH or fondaparinux + IPC

National Bariatric Surgery Registry

Guidelines for VTE Prophylaxis in Asia HK:

Guideline for orthopedics and ICU patients

Japan: Japanese guidelines for prevention of VTE 2004

Decrease in perioperative VTE

Korea: Korean guidelines for the prevention of VTE

Malaysia: Prophylaxis of VTE, clinical guideline

JAPAN

Korean guidelines for prevention of VTE 2010

Hong Kong

NO unique guideline for general surgery Guidelines for ICU, neurosurgery and

orthopedics patients

Hong Kong

TMH/PMH ICU

Guideline in Hong Kong

Step 1: Identify high risk surgical procedures or injury

Step 2: other VTE risk factors Step 3: Risk stratification Step 4: Assess bleeding risk or

contraindication Step 5: Select appropriate

thromboprophylaxis Step 6: Reassess

Bring home message

Do not ignore venous thromboembolism (VTE)

Incidence is rising in Asian population Prophylaxis and Guidelines with

reference to other Asian countries should be considered

Further RCT required

Thank you

Risk factors for DVT

Stasis Surgery, trauma,

immobility, paresis Increasing age Pregnancy and

postpartum Heart or respiratory

failure Obesity

Vessel Injury Previous DVT Smoking Varicose veins Central venous

catheterization

Hypercoagulability Increasing age Malignancy Cancer therapy Estrogen therapy

(OCP or HRT) Acute medical illness Inflammatory bowel

disease Nephrotic syndrome Myeloproliferative

disorders Paroxysmal nocturnal

hemoglobinuria Inherited or acquired

thrombophilia

Chinese population

NOT UNCOMMON! Annual incidence of VTE in HK Chinese

16.6 events per 100,000 population 3 per 10,000 hospital admissions

Autopsy study in adult HK Chinese population PE: 0.75%

Postoperative incidence (120940 surgical operations) DVT: 0.13% PE: 0.04% Epidemiology of VTE in a Chinese population Br J Surg 2004;91:424-8

Pulmonary thromboembolism and venous thrombosis in the Chinese Clin Ortho 1980;150:253-60

Chinese population

Incidence of DVT after colorectal surgery in a chinese population Open surgery 38.9% Laparoscopic surgery 50%

Study showed 41.7% developed asymptomatic postop DVT in postop colorectal cancer patients in HK

Noted increase prevalence in HK DVT 2.6-17% PE 0.75-4.5%

INCIDENCE OF DEEP VEIN THROMBOSIS AFTER COLORECTAL SURGERY IN A CHINESE POPULATION ANZ J. Surg.(2001)71, 637–640

Chinese population

Prevalence of DVT in different surgery Orthopedic surgery 53.3% Neurosurgery 10% General surgery 8.5% Colorectal surgery 4%

Surgical patients: Anaesthetic time >90mins Anaesthetic time >60mins + operation

involves pelvis or lower limb Acute surgical admission with inflammatory

or intraabdominal condition Expected reduced mobility Any VTE risks factors

Mechanism of Heparin

• Unfractionated heparin inactivates both Factor IIa and Xa

• LMWH has increased affinity for Factor Xa

• Fondiparinux is only a pentasaccharide sequence

Bleeding risk

Acute bleeding Acquired bleeding disorders eg acute liver

failure Concurrent use of anticoagulant eg warfarin Acute stroke Thrombocytopenia (Plt <75) Untreated inherited bleeding disorders (eg

hemophilia)

Major bleeding

Death Decrease in Hb >/=2 Transfusion of at least 2 units Bleeding from retroperitoneal,

intracranial or intraocular site

Contraindication for mechanical prophylaxis Suspected or proven peripheral arterial

disease Peripheral arterial bypass grafting Peripheral neuropathy or other causes of

sensory impairment Allergy Severe leg edema Major limb deformity Local skin condition eg dermatitis, gangrene

etc

New oral anticoagulants

Factor Xa inhibitors: apixaban and rivaroxaban

Factor IIa inhibitors: dabigatran

No need for routine coagulation monitoring

No major food interactions Limited drug-drug interactions Trial on orthopedic surgery