Monday, February 23, 2009

Prevent Pulmonary Thromboembolism – 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Updated 3/2017-- all links (except to my own posts) removed as many no longer active.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. 

The full title of the article is “The Efficacy of Prophylactic Low-Molecular-Weight Heparin to Prevent Pulmonary Thromboembolism in Immediate Breast Reconstruction Using the TRAM Flap.”   The full reference is below.

Deep vein thrombosis (DVT) and pulmonary thromboembolism  (PE) are complications that may lead to fatal consequences.  For most patients undergoing plastic surgery, these complications are uncommon.  There is one exception – abdominoplasty.  The reported incidence with this procedure is reportedly 1.1 percent. 
The transverse rectus abdominis musculocutaneous (TRAM) flap has the same risk factors as an abdominoplasty (ie obesity, abdominal flap elevation interfering with venous return of the superficial venous system of the pelvis and lower extremity, long surgery time, decrease mobility postop, etc).  TRAM flap patients have the additional risk factor of cancer. 
Malignancy causes a procoagulant state, with abnormalities in blood flow and vessel wall and blood composition.  The overall risk of venous thrombosis was sevenfold higher in patients with malignancy than in persons without malignancy, and the risk of venous thrombosis was highest during the first few months after the diagnosis of malignancy.   In breast cancer patients, the adjusted odds ratio for venous thrombosis is 4.9, and up to 15 percent of breast cancer patients present with venous thromboembolism during the course of their disease.  Moreover, chemotherapy and hormone therapy, which are unavoidable, are significant precipitants of venous and arterial thrombosis.
The incidence of DVT and PE associated with patients undergoing immediate breast reconstruction with TRAM flaps has been reported to vary from 0.7 to 18.8 percent. 
The authors conducted a prospective study of the efficacy of prophylactic use of low-molecular-weight heparin to prevent PE.  They did this by looking at 650 consecutive patients who underwent immediate breast reconstruction with TRAM flaps between August of 2001 and April of 2007.   Group 1 included the first 450 patients treated prior to February 2006.  No medical prophylaxis was administered to Group 1.   Group 2 included the 200 consecutive patients treated since February of 2006.  This group was given a once-daily dose of 40 or 60 mg of enoxaparin for 7 days (depending on the patient’s weight), from the day of surgery.  All patients in group 1 and group 2 wore compression stockings until fully mobilized and began ambulation on the second postoperative day.
Fifty-four consecutive patients in group 1 (group 1c) and 68 consecutive patients in group 2 (group 2c) were routinely checked to detect asymptomatic PE on the third postoperative day.  The exams used included  serum D-dimer, pulmonary ventilation-perfusion scan, and pulmonary embolism computed tomography
The average age of the patients in both groups 1 and 2 was 42 years.  The average BMI was 22.6 kg/m2 in group 1 and 23.6 kg/m2 in group 2.   All patients had quit smoking at least 3 weeks before surgery, but 5.7 % of Group 1 patients and 3.5 % of Group 2 were ex-smokers.  The average stage of cancer was 1.48 in group 1 and 1.67 in group 2.  No patient had any history of coagulopathy, DVT, or PE.
Symptomatic thromboembolism was diagnosed in eight of the 450 group 1 patients (1.8 percent)
Asymptomatic pulmonary thromboembolism was detected in nine of the 54 group 1c patients (16.7 percent) who underwent routine workup for pulmonary thromboembolism.
Neither symptomatic nor asymptomatic pulmonary thromboembolism was diagnosed in group 2 patients.
Although the incidence of symptomatic pulmonary thromboembolism was lower in group 2, the difference was not statistically significant (p = 0.107). In contrast, the incidence of asymptomatic pulmonary thromboembolism was significantly lower in group 2c patients than in group 1c patients

They found the  most common symptom of symptomatic PE to be  chest discomfort (100 percent), followed by tachypnea, dyspnea, and cough. Most symptoms were developed on the second or third postoperative day.
Concerns are often raised about bleeding-related complications with the prophylactic use of low-molecular-weight heparin.  The authors  found no increases in significant bleeding-related complications, including transfusion rate. 
Clinical observation showed that enoxaparin-treated patients had more apparent bruising at the operation sites and the subcutaneous injection sites.
This is considered unavoidable, and meticulous hemostasis is required during every procedure throughout surgery, especially at the muscle stump and the deepithelialized flap surface.

The Efficacy of Prophylactic Low-Molecular-Weight Heparin to Prevent Pulmonary Thromboembolism in Immediate Breast Reconstruction Using the TRAM Flap; Plastic and Reconstructive Surgery:Volume 123(1)January 2009pp 9-12; Kim, Eun Key M.D.; Eom, Jin Sup M.D., Ph.D.; Ahn, Sei Hyun M.D., Ph.D.; Son, Byung Ho M.D., Ph.D.; Lee, Taik Jong M.D., Ph.D.

Other Blog Posts of Interest:
DVT Prevention
Graduated Compression Stockings

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