Factors affecting free tissue transfer success
Factors though to be important
Extrinsic factors
1. timing of reconstruction (for breast)
2. equipment
a. microscope
b. microinstruments
c. suture material
3. anaesthesia expertise
4. surgical expertise
5. technical issues
a. pedicle irrigation with heparin
b. end-end anastamosis vs end-to side
c. recipient site
6. postoperative nursing expertise
7. use of anticoagulants
8. use of insitu Doppler monitoring
Intrinsic factors
1. age
2. smoker
3. obesity
4. diabetes
5. atherosclerosis
6. renal disease
7. prothrombotic disorders
8. previous radiotherapy
Extrinsic Factors
Use of Vein grafts
 higher flap failure rate with use of vein grafts found (8.9%(5 of 56) versus 3.5
%(15 of 430) for non-vein-grafted repairs) – Khouri PRS 1998
 Arteriovenous loop found to increase flap failure odds by 22x (Nahabedian Ann
Plast Surg 2004)
Use of anticoagulants
 In rat models, use of single-dose heparin and single-dose dextran reduced
thrombosis rate
 Subsets of patients who benefit from the use of antithrombotic therapy include
replantation and free flaps performed immediately after injury. Thrombosis rates as
high as 35% have been described in this setting.
Dextran
 polysaccharide that is a product of fermentation of sucrose and has molecular
weights of 40(LMW) and 70.
 mechanism of reducing thrombus formation is not completely clarified. Known to
1. impair platelet function - increasing the electronegativity on platelets and
endothelium, thus preventing platelet aggregation
2. prolong bleeding time - decreasing factor VIII and von Willebrand factor,
3. destabilize fibrin polymerization.
4. volume expansion
5. microrheologic enhancement.
 Most studies show no benefit with elective free flaps but use is associated with
significant adverse reactions, such as anaphylactoid reactions, adult respiratory
distress syndrome, cardiac overload, hemorrhage, and renal damage.
 dextran syndrome characterized by acute hypotension, hypoxia, coagulopathy, and
anemia
Disa JJ, Polvora VP, Pusic AL, Singh B, Cordeiro PG. Dextran-related complications
in head and neck microsurgery: do the benefits outweigh the risks? A prospective
randomized analysis. Plast Reconstr Surg. 2003 Nov
 incidence of systemic complications was significantly related to the method of
prophylaxis, with patients receiving low-molecular-weight dextran 120 hours and
48 hours at a 7.2 and 3.9 times greater relative risk, respectively, of developing
a systemic complication compared with patients receiving aspirin
Heparin
 inactivates the coagulation factors XIIa, XIa, IXa, Xa, and IIa (thrombin)
 inhibition of thrombin and, subsequently, the inhibition of thrombin-induced
activation of factor V and factor VIII are primarily responsible for its
anticoagulant effect.
 In animal models, heparin increased arterial patency with no effect on venous
patencies
o Arterial thrombi more likely to be platelet activated whereas venous
thrombi more likely to be stasis related – fibrin+RBC
 In humans, likely to be useful for both
 local irrigant dose of 50-100U/ml helps prevent thrombosis without systemic side
effects.
 macrovascular surgery literature recommends intraoperative anticoagulation with
100 to 150 U/kg of intravenous heparin before cross clamping, supplemented with
50 U/kg every 45 to 50 minutes until anastomosis and the reestablishment of flow
 Kroll (PRS 1995)
o five groups: no anticoagulation, low-dose IVH, IVH given intraoperatively
with no postoperative anticoagulation, high-dose IVH, and dextran
o hematoma rates for the five groups of patients were 5.3%, 6.7%, 6.5%,
20%, and 9.1%, respectively.
o flap failure rates for these five groups of patients were 4.4%, 1%, 0%,
10%, and 27.2%
Aspirin
 acetylates cyclooxygenase and decreases the products of arachidonic acid
metabolism, including thromboxane, a potent platelet aggregator and
vasoconstrictor; and prostacyclin, a potent vasodilator and inhibitor of platelet
aggregation.
 Thromboxane is produced by platelet-derived cyclooxygenase, whereas
prostacyclin is produced from endothelial cyclooxygenase.
 Aim is to inhibit thromboxane
 minimal dose for complete suppression of thromboxane in humans is reported at
100 mg
 at low doses (up to 325mg), endothelial prostacyclin is not inhibited – shown to
more effective than high dose in reducing stroke, myocardial infarction, and death
 in rat studies , low dose aspirin inhibits anastomotic venous thrombosis and
improves microcirculatory perfusion
Postoperative nursing expertise
 Nurses trained to monitor flaps essential
 Higher incidence of flap loss covered by skin grafts (Khouri PRS 1998)
a. Thought to be due to increased difficulty with monitoring
Heparin Irrigation
 Use and concentration of heparin in the lumenal irrigating solution had no effect on
thrombosis or failure in the multivariable framework. (Khouri PRS 1998)

Intrinsic Factors
Age
Serletti JM, Higgins JP, Moran S, Orlando GS. Factors affecting outcome in freetissue transfer in the elderly. Plast Reconstr Surg. 2000 Jul;
 100 patients aged 65 years and older
 overall flap success rate was 97 percent
 higher ASA designation experienced more medical complications but not surgical
complications.
 Increased operative time resulted in more surgical complications
 ASA status and length of operative time are significant predictors of postoperative
medical and surgical morbidity
Howard MA, Cordeiro PG. Free tissue transfer in the elderly: incidence of
perioperative complications following microsurgical reconstruction of 197
septuagenarians and octogenarians. Plast Reconstr Surg. 2005 Nov
 197 patients over 10 years (retrospective)
 Flap survival was 100 percent in the 80+ group and 97 percent in the 70 to 79
group
 overall complication rate was 59.3 percent in the 80+ group and 35.3 percent in the
70 to 79 group
 medical complication rate was 40.7 percent in octogenarians and 11.8 percent in
septuagenarians
 Overall surgical complications were similar in the two groups.
 alcohol use and coronary artery disease were independent predictors of overall,
medical, and surgical complications.
Summary
 Age alone should not be considered a contraindication or an independent risk
factor for free-tissue transfer
 Patient selection is important for success
Irradiated recipient site
 Most studies with postmastectomy breast reconstruction show trends towards
increased complication (not reaching significance)
Diabetes
 Multiple studies have shown that diabetes does not lead to an increased risk in
anastamotic failures
Smoking
 Effect most seen in digital replantations
o Due to vessel spasm rather than anastamotic failure, digit different from
other free flaps as vessel is predominantly under vasomotor control
o Nicotine shown to cause digital blood flow reduction in normal fingers –
24%-42% with a single cigarette taking up to 90 minutes to normalize
o 80-90% of smokers will lose their replanted digits if tobacco use occurs
within 2 months before surgery
 Most studies for head/neck and breast reconstruction show comparable
anastomotic success rates in smokers compared to nonsmokers
o 1 study showed increased failure (Nahabedian Ann Plast Surg 2004 – 102
head and neck reconstruction)
Obesity
 Free TRAM reconstruction of 939 patients, Chang PRS 2000 found obese
(BMI>30) patients had a 3.2% vs 0% for normal weight patients for total flap loss
Renal disease
Moran S; Free tissue transfer in patients with renal disease. PRS June 2004
 6% flap failure at 1 month
 52% incidence of major morbidity or mortality during 1st year
 55% reconstructive success at 1 year
Summary
 Renal failure does not adversely affect immediate graft patency rates
 Higher surgical (bleeding, infection) and medical perioperative complications
 However associated with high risk of late reconstructive failure
Peripheral vascular disease
Moran SL, Illig KA, Green RM, Serletti JM. Free-tissue transfer in patients with
peripheral vascular disease: a 10-year experience. Plast Reconstr Surg. 2002 Mar;
 10-year experience with free flaps for limb salvage in patients with peripheral
vascular disease
 79 flaps
 In first month, four cases of primary flap loss, and another two were lost as the
result of bypass graft failure (8 percent)
 5-year flap survival was 77 percent, limb salvage 63 percent, and patient survival
67 percent.
 Free-tissue transfer for lower extremity reconstruction can be performed with
acceptable morbidity and mortality in patients with peripheral vascular disease.
 Flap loss is low, and limb salvage, ambulation, and long-term survival rates in
these patients are excellent.
Prothrombotic Disorder
Arnljots B, Soderstrom T, Svensson H. No correlation between activated protein C
resistance and free flap failures in 100 consecutive patients.PRS 1998
 In a consecutive series of 100 patients, failure was more related to technical issues
than a prothrombotic disorder
 concluded that routine screening for hypercoagulable states such as activated
protein C resistance is not necessary in microvascular surgery.