Monday, September 7, 2009

Hypercoagulability as Cause for Flap Failure – an Article Review

Updated 3/2017-- all links (except to my own posts) removed as many no longer active. and it was easier than checking each one. 

Even though I no longer do microvascular surgery, I found this article very interesting.  I can recall a few patients that “fit” the description of their patients.  I wonder if had we recognized the possibility of a hypercoagulability state in the patient and worked them up what would have been found.
Flap failure rates using microvascular free flap techniques have  dropped to under 3 percent in most large series of high-volume centers.  Even with greater experience, improved technology, and development of anastomotic devices, the average failure rate has not dropped below 1 to 3 percent. 
This article discusses the failures due to undiagnosed coagulopathies the patient may bring into the mix.  The authors presented four cases.  Unfortunately sometimes the first presentation of coagulopathy might be microvascular complications of the free flap.
The authors noted that all fours of their cases were similar intraoperatively:
Intraoperative findings that were common to these failed anastomoses were as follows:
1. The arterial anastomosis does not flash when the clamp is removed; it requires manipulation.
2. The arterial anastomosis goes down quickly (within 1 hour), before the rest of the procedure is completed.
3. The vessels, particularly the recipient flap vessels, are flaccid.
4. Topical agents such as papaverine and lidocaine do not appear to resolve the perfusion problem.
5. Heparin may make it worse.
6. Administration of intravascular thrombolytic agents (Activase; Genentech, Inc., South San Francisco, Calif.) provides instant bright red bleeding from every cut surface, but thrombus quickly reaccumulates at the anastomotic site.

The authors note that no routine, inexpensive, specific screening test predicts for the development of hypercoagulopathy-related perioperative complications. You can screen for deep venous thrombosis risk and measure prothrombin time and partial thromboplastin time.  This will identify some patients with possible coagulopathies.
The authors give some nice advice for management once a diagnosis of a hypercoagulable state is established.
First, the operative defect should be temporized using dressing changes until more definitive reconstruction can be safely performed.
Second, immediate perioperative anticoagulation needs to be initiated, as the hypercoagulable state places the patient at high risk for postoperative venous thromboembolism/deep venous thrombosis.
Third, plans for long-term anticoagulation, if any, need to be coordinated with the hematology service. Some hypercoagulable patients (those with lupus or malignancy) might need protracted anticoagulation, whereas other patients simply require counseling on anticoagulation strategies during future scenarios associated with high risk of venous thromboembolism, such as operations, long plane flights, pregnancy, and other conditions that might unmask their predisposition to hypercoagulability.

Microvascular Free Flap Failure Caused by Unrecognized Hypercoagulability; Plastic & Reconstr Surgery: August 2009, Vol 124 (2), pp 490-495;  Davison, Steven P. D.D.S., M.D.; Kessler, Craig M. M.D.; Al-Attar, Ali M.D., Ph.D. [doi: 10.1097/PRS.0b013e3181adcf35}

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