What to Know About Deep Vein Thrombosis Prophylaxis

With no official guidelines specific to otolaryngology on perioperative precautions to prevent deep vein thrombosis (DVT), otolaryngologists may not have all the information they need about risks facing their surgical patients.

“Nearly every other surgical sub-specialty has their own guidelines, but we don’t, so we are sometimes forced to make it up on the fly,” said Charissa Kahue, MD, head and neck and micro-vascular surgery fellow at the University of Kansas
Medical Center.

After the otolaryngology department at her hospital recently had three postop patients in one week develop pulmonary emboli—a highly unusual situation—Dr. Kahue examined the literature, created a presentation for her colleagues, and drafted a protocol for head and neck cancer patients.

“It was an unfortunate series of events to have had so many that close together,” she said, adding that this number might normally occur in six months or a year.

Physicians reviewing each case concluded that everything had been carried out according to hospital and American Academy of Chest Physicians guidelines for non-orthopedic surgery (the umbrella that covers otolaryngology). But upon further examination, Dr. Kahue noted that there were additional specific cancer guidelines from the American Society of Clinical Oncology, and that, within otolaryngology, practices for venous thromboembolism (VTE) prophylaxis were highly variable.

CHEST Guidelines and Caprini Scores

In 2012, the American College of Chest Physicians issued guidelines for VTE in non-orthopedic surgical patients, concluding that “optimal thromboprophylaxis in non-orthopedic surgical patients will consider the risks of VTE and bleeding complications as well as the values and preferences of individual patients.”

The guidelines described alternatives for stratifying VTE risk in general and abdominal-pelvic surgical patients, based on risk factors, with similar recommendations for other non-orthopedic surgical populations. 

Risk factors used in the guidelines (CHEST. 2012;141(2):e419S–e496S) are based on Caprini scores, which physicians can use to assess an individual patient’s risk for developing DVT based on a variety of conditions.

“The Caprini score was developed for general surgery, but it has been applied pretty widely outside,” said John Cramer, MD, assistant professor of otolaryngology at Wayne State University in Detroit. “It’s been validated in ENT as well.” Dr. Cramer added that otolaryngologists with an interest in DVT and pulmonary embolism (PE) prophylaxis are using either the Caprini score or some other risk-based system to assess patients.

Otolaryngology-Specific Guidelines

According to a 2016 survey published in Head and Neck, practices in venous thromboembolism prophylaxis vary widely among otolaryngologists. The survey, which comprised 26 questions emailed to 4,376 otolaryngologists, had a response rate of 15.4%.  Eighty-three percent of respondents said they used intraoperative prophylaxis with intermittent pneumatic compression (91.8%), compression stockings (35.9%), or low-molecular-weight heparin (LMWH; 12.3%). Eighty-five percent used postoperative prophylaxis with early ambulation (87.8%), intermittent pneumatic compression (85.4%), compression stockings (43.3%), or low-molecular-weight heparin (42.4%). The majority of the otolaryngologists surveyed (86%) reported that, from 2012-2013, their institutions had variable practice guidelines and 32% did not routinely follow them. The reasons for non-compliance included a perceived low VTE risk and concern for bleeding. Eighty-eight percent of respondents said it would be helpful if the American Academy of Otolaryngology–Head and Neck Surgery released thromboprophylaxis guidelines (Head Neck. 2016;38:E341–E345).

Dr. Cramer said a lack of data may be the reason guidelines specific to ear, nose, and throat surgery don’t yet exist for VTE prevention. “I think the evidence basis has taken longer to emerge than other surgical fields, and there wasn’t enough data when they made the CHEST guidelines, which are probably the most authoritative,” Dr. Cramer said. He added that surprisingly little has been published in otolaryngology and that most of it is on retrospective, single-institution experiences with no randomized trials. “I think the retrospective experience has been accumulating and getting to be somewhat significant,” he said, “so at least we can make some comparisons to more established fields.”