Evidence Table 1Surgical risk of VTE: incidence studies

PaperAsymptomatic DVTSymptomatic VTEFatal PEPEType of prophylaxisType of SurgeryNotes
Andtbacka et al., 200619Not reportedwithin 60 days:

7/3898 (0.16%) VTE

3/3898 (0.07%) DVT only
No deaths.3/3898 (0.07%)No prophylaxis:General (breast cancer)3898 breast cancer patients.
4416 operations.
Length of operation given as a risk factor, result broken down using this.
N/A Study draws correlation between operation length and development of VTE.
Mean operative time (in patients dev VTE) = 278 mins
Mean operative time (no VTE) = 256 P = 0.7
Auguste et al., 2003256/180 (3.3%) (Exact one-tailed 95% upper CL 6.5%) developed VTE.

Of these:
3 (1.7% exact one- tailed 95% upper CL 4%) developed contralateral DVT
1 (0.6% exact one- tailed 95% upper CL 2%) developed ipsilateral DVT
6/180 (3.3%) (Exact one-tailed 95% upper CL 6.5%) developed VTE.No deaths.2/180 (1.1%) (Exact one-tailed 95% upper CL 4.8%)Intraoperative:
antiembolism stocking plus compression device.
Post operative:
bilateral mechanical prophylaxis (compression stockings)
Craniotomy and motor mapping for glioma
180 patients – all diagnosed with glioma, no history of DVT.
Mean operation length given as 7.7 hrs, further info in paper.

Wilcox test demonstrated no significance between clinical VTE and age, duration of surgery, preoperative values for prothrombin time and partial thromboplastin time.

Obesity, BMI, smoking not included in analysis.
Bjornara et al., 200663Not reportedTotal:
150/5607 (2.7%, CI 2.2–3.1)

Confirmed DVT:
Hip fracture surgery:
36/2420 (1.5%) CI 1.0 to 2.1
39/2512 (1.6%) CI 1.1 to 2.1
11/675 (1.6%) CI 0.8–2.9
1.5% (95%CI 2.2–3.1)
Hip fracture surgery:
32/2420 (1.3%) CI 0.9–1.9
28/2512 (1.1%, CI 0.7–1.9)
4/675 (0.6% CI 0.2–1.5)
1.1% (95%CI 0.9–1.4)

7 patients developed DVT and PE
0.1%, 95% CI 0.9–0.2
Thromboprophylaxis LMWH for approx ten days or until discharge.
Subcutaneous dalteparin (5000 IU) or enoxaparin (40 mg) 12 hours preoperatively.
OrthopaedicAll patients undergoing major hip and knee surgery who were diagnosed with objectively confirmed VTE within 6 months of surgery.

Broken down by time of diagnosis (during initial hospitalisation/after discharge)

Also broken down by type of surgery.
Fletcher and Batiste, 199718714/121 (9.8%) DVT incidence

9.1% incidence for reconstructive surgery
14.3% for amputation.
Not reportedNot reported1/121 (0.7%)5000 unit of unfractionated heparin 3x daily, preoperative-mobile, and intraoperative sequential compression devices.Vascular Repair of abdominal aortic aneurysm, reconstruction of lower extremity arterial occlusive disease or amputation.Major bleeding 3/121
Gordon- Smith et al., 1972229Control:
9/32 (28%)
9/30 (30%)

Not significant.
Not reported1 fatality in control from MI

1 fatality in control from PE 1/30 (3.3%)
1/32 (3%)
2/30 (6%)

Not significant.
6g EACA in the intervention group 5 hours preoperatively.Urology (prostatectomy)RCT: 32 control, 30 int., 50yrs+
Howie et al., 2005288Not reportedDVT (including fatal PE)
At 90 days:
Hip: 22.0/1000 (2.2%)
(OR 14.8 (95% CI, 12.9 to 16.9)
Knee: 17.3/1000 (1.7%)
(OR 11.62 (95% CI, 10.0 to 13.5)
Cataract: 1.5/1000 (0.15%)

At 365 days:
Hip: 25.8/1000
Cataract: 4.9/1000
At 90 days:
Hip: 2.2/1000
Cataract: 0.3/1000

At 365 days:
Hip: 2.7/1000
Cataract: 1.24/1000
Not reportedNot reported.Orthopaedic:
Knee arthoplasty:: (n=27503)
hip (n=44785)

cataract (n=176520)
Data retrieved from the Scottish Morbidity Record (SMRO1) system between 1992–2001 of all patients that had hip or knee arthroplasty or cataract surgery.

Majority of fatal PE after arthroplasty is significantly higher than for cataract cases with majority of deaths occurring between discharge and six weeks post- operatively. Low incidence of autopsy (<10%) in this study.

Cataract patients were slightly older than those undergoing arthroplasty.

* NHSSCOTLAND2006485 reports on DVT/PE incidences from SMRO1 records but only in graphical form and not exact figures.
Joffe, 197530910/23 (43%) postoperative DVT

6/10 (60%) of spinal operations developed DVT

4/13 (38%) of craniotomy operations (p<0.2)
1/23 (4%) developed symptomatic DVTNot reportedNoneNo prophylaxis reportedNeurosurgery23 patients.
Age, sex, length of hospital stay given as not affecting results. Obesity and previous DVT history as risk factors.

Study aims to compare screening techniques: Doppler/I fibrinogen.

No conclusions drawn about efficacy of screening technique or prophylaxis
Keeney et al., 200633425/705 (3.5%) asymptomatic week after surgery

Of whom 17/25 (68%) had proximal DVT.

5/705 (0.7%) presented with pain within 3 months, all proximal DVT.

4.2% Total of which:
1.1% distal
3.1% proximal
Not reportedNot reported1/705 nonfatal PE. (0.1% )Pneumatic compression, adjusted dose warfarin (7 days), early mobilisation.Orthopaedic (elective hip)Increased age (p=0.008), male sex (p=0.005), DVT history (p=0/0005) identified as risk factors significantly associated with DVT.
Martino et al., 2006428Not reportedNot reportedNot reportedCancer patients:
21/507 (4.1%)
Benign patients:
1/332 (0.3%)
p<0.001 95% CI 1.9–102.1
minor/non- abdominal surgery:
2/536 (0.4%)
Prophylaxis with intermittent compression and early mobilisation, preoperatively extending through discharge.Major abdominal surgery in Gynaecological oncology1373 surgery patients, 839 (507 cancer diagnosis, 332 benign) major abdominal surgery cases, 534 minor abdominal surgery cases

Cancer, age of 60+ identified as risk factors (p = 0.009 95%CI)
Data also given on different types of oncological surgery.
Mayo et al., 1971432Open prostatectomy 21/41 (51%)
Transurethral resection 2/20 (10%)

Total: 32/61 (38%)
Not reported6g EACA in first 12 hours postoperativelyUrology (prostatectomy)61 patients.
Operation type, length, age, bed rest, blood given all entered into analyses as risk factors. See p 741.
Moreano et al., 1998461Total: 34/12805 (0.3%)
DVT: 0.03% (general otolaryngology)
6% ( in patients with low dose heparin)

General otolaryngology (GO) 3/4563 (0.1%)
Head and Neck (H&N) 21/3463 (0.6%)
Otology/Neurology (O/N) 8/2526 (0.3%)
Trauma and Plastic Surgery (T/P) 2/2254 (0.1%)

Not reported
0.02% (general otolaryngology)

0.21% (in patients with low dose heparin)

H&N 0.06%
Total: 24/12805 (0.2%)

0.52% (in patients with low dose heparin)

GO 2/4563 (0.04%)
H&N 14/3463 (0.4%)
O/N 6/2526 (0.2%)
T/P 2/2254 (0.1%)
In the 34 patients who developed DVT:

No prophylaxis: 12 (34%)
Prophylaxis: 22 (65%)

Of which:
11 (32%) preoperative compression device
2 (6%) postoperative compression device
9 (26%) stockings only.
Various Incidence broken down by surgery type.

Effectiveness data on GO group by type of prophylaxis.
12805 operations Number of patients not given.
Discussion of development of risk- categorisation for patients.
Phillips et al., 2003518Not reportedNot reportedNot reported0.9% within 3 monthsNo prophylaxis reportedOrthopaedic (elective hip)Medicare records for total hip replacements for one year (retrospective study)
71477 patients. Incidence for various time periods given, calculated as number of events per 10, 000 person- weeks
Broken down by weeks and also compares primary with revision hip replacements.
Saarinen et al., 1995566Not reportedNot reportedNot reported34/7533 (0.45%) postoperative DVT (21 Male, 13 female, mean age 63)Not reported.VascularFINNVASC (Finnish vascular registry) data.
Breaks down incidence by risk factor see p 127, e.g. hyperlipidaemia, smoking, etc. Compares DVT patients with non-DVT patients for distribution of vascular operations and risk.
94% of PEs had undergone vascular procedure involving infrarenal aorta or lower extremity.
Sinclair et al., 1976604No significant difference between groups.

20/40 (50%) evidence of DVT

of which:

13/19 (68%) of prostatectomy patients developed DVT
7/21 (33%) of transurethral resections
Not reportedNot reportedNot reportedEACA in the intervention group, 0.5g per hour for twelve hours, then 6g twice daily for ten days.Urology (Elective retro- pubic prostatectomy)Double blind RCT to assess effectiveness of EACA.
Incidence broken down by intervention groups and also by type of surgery.
I-fibrinogen test used to identify DVT.
Valladares and Hankinson, 198065229/100 (29%) developed DVT

Of whom: 16/36 (44%) of those with known risk factors developed DVT.

Of those without risk factors, 13/64 (20.3%)
Not reportedNot reportedNot reportedNo prophylaxis reportedNeurosurgery (major cranial or spinal operations)100 patients undergoing major cranial or spinal operations.
Broken down by specific type of surgery, and also by risk factor, e.g. age,.“leg weakness”, length of op, given as particular risk factors
Warwick et al., 1995677Not reportedOverall venographically proven DVT rate 22/1162 (1.89%, CI 1.11–2.76)4/1162 (0.34%) CI 0.09–0.8814/1162 (1.20%, CI 0.657 to 2.02)Standard practice: stockings and early mobilisation, Anticoagulant prophylaxis was not used routinely but reserved for those considered to be at the greatest risk of thromboembolism.OrthopaedicReview of records of 1112 patients who had 1162 primary or revision THR

Total early morbidity from VTE 3.4% In-patient, all cause mortality rate of 0.86% (10/1162)

90-day mortality rate 1.3% (1.1%, 15/1162)

Total thromboembolitic morbidity : 3.4% (95%, CI 2.5%–4.7%)

From: Appendix D, Evidence tables

Cover of Venous Thromboembolism
Venous Thromboembolism: Reducing the Risk of Venous Thromboembolism (Deep Vein Thrombosis and Pulmonary Embolism) in Patients Admitted to Hospital.
NICE Clinical Guidelines, No. 92.
National Clinical Guideline Centre – Acute and Chronic Conditions (UK).
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