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Panel 6: Thrombosis Risk-Assessment As A Guide To Thrombosis Prophylaxis In Surgical Patients

Surgeon General's Workshop on Deep Vein Thrombosis

1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16

SLIDE 1: Thrombosis Risk-Assessment As A Guide To Thrombosis Prophylaxis In Surgical Patients

Joseph A. Caprini, M.D., M.S., FACS, RVT, FACPh
Louis W. Biegler Professor of Surgery and Bioengineering
Department of Surgery, Evanston Northwestern Healthcare, Evanston, IL
Northwestern University, The Feinberg School of Medicine, Chicago, IL
Robert R. McCormick School of Engineering and Applied Sciences,
Northwestern University, Evanston, IL

SLIDE 2: Levels Of Thromboembolism Risk In Surgical Patients Without Prophylaxis

Level of Risk	Calf DVT,%	Proximal DVT,%	Clinical PE,%	Fatal PE,%
Moderate	10-20	2-4	1-2	0.1-0.4
Low	2	.04	.02	<0.01
Geerts WH, et al, Chest 2004;126 Suppl 3:338S-400S

SLIDE 3: Levels Of Thromboembolism Risk In Surgical Patients Without Prophylaxis

Level of Risk	Calf DVT,%	Proximal DVT,%	Clinical PE,%	Fatal PE,%
Highest	40-80	10-20	4-10	0.2-5
High	20-40	4-8	2-4	0.4-1.0
Geerts WH, et al, Chest 2004;126 Suppl 3:338S-400S

SLIDE 4: ACCP Guideline-Defined” Risk of Venous Thromboembolism in Y2002 (hospital discharges)

Highest risk surgery	744,465
High risk surgery	3,031,318
Moderate risk surgery	2,019,696
Surgical Total	5,795,479

13,392,124 / 37,804,021 = 35% of all hospital discharges

SLIDE 5: VTE Incidence

Probability of Pulmonary Emboli (%)

	Without prophylaxis %	With prophylaxis %	Prophylaxis utilization %
Surgical	PE	PE
Moderate risk	5.2	2.7	40
High risk	10.3	5.4	65
Highest risk	24.1	12.6	85

The majority (93%) of estimated VTE-related deaths in the US were due to sudden, fatal PE (34%) and 59% of these fatalities were in those with undiagnosed VTE (59%).

Given that effective VTE prophylaxis and expert consensus prophylaxis guidelines are widely available, these data suggest that universal safe and effective prophylaxis could significantly reduce US VTE incidence and related deaths.

SLIDE 6: Fatal Pulmonary Embolism

Randomized double-blind comparison of LMWH with UFH, involving 23,078 patients, 73.9% of whom underwent general surgery

	LMWH (N = 11,542) N (%)	UFH (N = 11,536) N (%)	p
PE (at autopsy)	22 (0.191)	22 (0.191)
Fatal	17 (0.147)	18 (0.156)	0.87
Non-fatal	5 (0.043)	4 (0.035)	1

If Seventeen Plane Crashes Occurred For Every 11,542 Airline Flights, No One Would Fly

SLIDE 7: No title

It Takes 13 days at 900 departures/day to equal 11,700 flights which means 17 crashes at Ohare every 13 days--- or more than one daily

SLIDE 8: Patient Intake Form

Personal History of DVT or PE
Family History of DVT or PE
Malignancy: Current or Previous
Personal History of Recent MI or stroke (< 1 month)
Recent Major Surgery (< 1 month)
Currently on BCP, HRT, or hormonal therapy for Breast or Prostate Cancer
Current or recent acute inflammatory or infectious process (< 1 month)
Currently immobile (unable to ambulate in the in-patient setting)
History of unexplained stillborn infant, recurrent spontaneous abortion.premature birth with preeclampsia or growth-restricted infant.
Swollen legs
Varicose Veins
Obesity (BMI > 30)
Age

Graphic of the Thrombosis Risk Factor Assessment Intake Form

SLIDE 9: SUBCUTANEOUS LOW-DOSE UNFRACTIONATED HEPARIN

Investigator	Kakkar 1975	Kakkar 1975	Collins 1988	Collins 1988
Group	Control	Heparin	Control	Heparin
DVT (all values are highlighted in this row)	29.60%	9.40%	27.40%	10.60%
Fatal PE	38 (1.7%)	20 (0.9%)	114 (3.4%)	67 (1.7%)
Bleeding	5.80%	8.80%	1.80%	3.10%
Patients	4,000	4,000	16,000	16,000
Centers	28	28	70	70

Efficacy and safety validated in 98 centers and 20,000 patients over a 13 year period when control groups and venographic confirmation were allowed

SLIDE 10: Comparison of 16 Clinical Trials

Data from 16 clinical trials conducted 1980-2003
- Trials selected based on initial computerized literature search including PubMed, EMBASE
- Compared LMWH vs UFH, placebo, or other LMWH
- No formal statistical meta-analysis performed

Conclusions:

Patients undergoing abdominal surgery should be stratified by risk for thromboembolism and managed accordingly
LMWH is a recommended alternative to UFH in moderate- or high-risk patients
In patients with cancer:
- High-dose LMWH may offer increased benefits without increased bleeding
- Extended 4-week period of prophylaxis appears beneficial

SLIDE 11: Venous Thromboembolism Prophylaxis Following Orthopedic Procedures

Type Of Procedure	Patients	Pentasaccharide	LMWH
Total Hip Replacement Europe, etc. ( 22 countries)	1723	4.1%*	9.2%
Total Hip Replacement North America	2257	6.1%	8.3%
Total Knee Replacement	1034	12.5%*	27.8%
Hip Fracture Repair	1711	8.3%*	19.1%
Extended Hip Fracture Repair Venogram=30 day	426	7 days Fondaparinux 35%	30 Days Fondaparinux 1.4%*

*p<.0001

SLIDE 12:VTE Prophylaxis In General Surgery

Bar chart showing VTE Prophylaxis In General Surgery (combined modalities) with Fondaparinux 1.7% 7/424 and Placebo 5.3% 22/418

Odds reduction = -69.8% (95 %CI : -87.3; -27.9%) p = 0.004

Lowest venographic DVT rate ever seen in general surgery

SLIDE 13: Fondaparinux: Major Bleeding Up to Day 11 By Study

	Knee Replace	Hip Replace	Hip Replace	Hip Fract Surg
Fondaparinux	2.1*	4.1	1.8	2.2
Enoxaparin	0.2	2.8	1	2.3
*P0.006 for Fondaparinux vs enoxaparin for major bleeding up to 11 days after major knee surgery; major bleeding included bleeding that was fatal, retroperitoneal, intracranial, intraspinal, in a critical organ, led to reoperation, or had a bleeding index 2.

*Bleeding With a Positive BI Largely Accounts for Higher Bleeding Incidence

SLIDE 14: Intermittent Pneumatic Compression And Deep Vein Thrombosis Prevention

Combined Modalities

A meta-analysis in postoperative patients

A total of 2,270 patients were included in 15 eligible studies: 1,125 in the IPC group and 1,145 in the no prophylaxis group.
IPC devices reduced the risk of DVT by 60% (relative risk 0.40, 95% CI 0.29 – 0.56; p< 0.001)
The authors suggest that further randomized trials are warranted to test the utility of IPC in hospitalized medical patients as well as combination pharmacological-IPC prophylaxis in both medical and surgical patients.

SLIDE 15: When to Think About Pneumatic Compression

Patients with 2-3 risk factors
Patients with >4 risk factors in combination with anticoagulant prophylaxis
Patients with hemostatic defects like hemophilia, Von Willebrand’s disease, platelet functional defects, heparin induced thrombocytopenia, etc
Patients with bleeding disorders, bleeding ulcers, bleeding from colitis or ileitis, acute hemorrhagic stroke.
Patient needing craniotomy or spinal cord surgery.
Patients requiring complex cancer operations associated with large blood loss such as a pancreatoduodenectomy, major hepatic resection, or extensive pelvic resection, etc.
Patients with closed head injuries, pelvic hematomas, and/or other complex trauma situations.

SLIDE 16: Conclusions

Individual risk assessment key to appropriate prophylaxis
IPC is very effective for those who have 2-4 risk factors
Combined physical and pharmacologic methods appropriate for the highest-risk individuals
UFH is effective but relatively high incidence of HIT, poor anticancer effects, and difficult outpatient use are problems
LMWH offers greater effectiveness, lower HIT incidence, good anticancer effects, and excellent 30 day postoperative efficacy
Fondaparinux offers excellent efficacy, no worry about HIT, the lowest reported incidence of DVT in hip, knee, and hip fracture patients. Early data show the lowest DVT rates in abdominal surgery cancer patients especially when combined with IPC.