Compression therapy is effective, but when to start it is unclear
Guidelines for compression therapy in question
According to James C. Watson, MD, FACS, board-certified vascular surgeon and co-medical director of the Northwest Hospital Wound Care Center in Seattle, when to begin lower leg compression therapy for venous ulcers is a hot topic right now. Traditionally, the concern about using compression therapy has been that if the patient had a clot in a deep vein and compression was used on the vein distal to it, that clot would be squeezed out and move back to the heart, where it could cause pulmonary embolus. "I think that’s true for a day or two," Watson says, "but after that time the clot becomes fixed to the wall of the vein and it’s very rare that it will squirt up to the heart. I tell people to take a couple of days, take it easy — after that they need to keep their feet elevated, and I move right to compression."
Deep venous thrombosis (DVT) is the No. 1 reason people develop venous hypertension and consequent ulcerations. Watson notes that although compression therapy does not directly affect the healing response, it does remove the poor calf muscle pump function, edema, and lack of oxygen and nutrient exchange with carbon dioxide and metabolites, which are underlying causes for the ulcer. "If you get the fluid and swelling out of the leg, that allows the tissue to get oxygen and nutrients from the blood because there’s not a lot of fluid in the way. So the compression doesn’t affect your ability to heal a wound, other than taking out the factors that have prevented that healing."
DVT doesn’t always show symptoms
While there can be outward signs of DVT such as redness and swelling, symptoms don’t have to be present. "It depends on the location," Watson says. "If it’s a proximal deep vein thrombosis, as in the groin or proximal thigh, most people get some swelling, bring it to the attention of their doctors, and get diagnosed."
Watson says the deep venous thromboses that cause venous insufficiency and ulcers are usually the ones in the bigger veins. "This is a chronic problem. I tend not to prescribe compression therapy right away because the damaged valve takes a while to damage the subcutaneous tissue and cause the ulcer, and there is some risk. It’s very small, but there is some risk of causing a pulmonary embolus from doing that. It’s sort of like saying, Doctor, is there any chance I’ll get hit by lightning today?’ Well, yes, there is a chance, but it’s not very likely."
During a recent exchange of opinion on the Wound, Ostomy and Continence Nurses Association Web site, Ruth Bryant, RN, MS, CWOCN, a partner in Bryant-Rolstead Consultants in St. Paul, MN, estimates that only about 25% of all DVTs are diagnosed. As for determining how soon compression therapy can or should be started after a diagnosis of DVT, Bryant says, "I have not seen this particular question asked in the literature as yet. Ideally, the physician would conduct another test on the leg — i.e., plethysmography or a scan — to verify resolution of the clot, which would imply it is safe to resume compression. Without that information, you might be wise to consult with a hematologist about clot resolution so you and the patient’s physician could make a judgment about compression. It would be nice to have someone write in who says, resume one month post-DVT treatment initiation,’ but I would bet such an answer would be more [based on experience] rather than research-based. Quite honestly, this is an important question because all patients with a DVT should be instructed in compression therapy."
"I’m a real fan of compression, and I don’t believe you have to wait to use it for months after a deep venous thrombosis," Watson says. He advises patients to use elevation — which he says has essentially the same effect as compression — before starting compression therapy, and adds that in lower-extremity ulcers, the presence of necrotic tissue can cause the infection and inhibit granulation and healing. "You need to debride the ulcer down to healthy, non-infected alive tissue and allow granulation to start. Occasionally, it won’t heal quickly enough. There are several growth factors derived from patients’ blood, as well as a new product called Regranex, that tend to help stimulate granulation. If these don’t work, or if the patient wants things done more quickly, we do skin grafts."
Joan Nowicky, RN, CWS, of Huntley Health Care in Malapan, NJ, says compression therapy for acute DVT is contraindicated by all manufacturers of pneumatic compressive devices. "Most vascular surgeons I’ve talked with define DVT as acute if the condition is less than three months old," she says. "The reason compression is contraindicated in acute DVT is the concern that the thrombus may be dislodged and allowed to embolize. Even that’s controversial at this point. I’ve heard various people speak about studies done on intraluminal pressures with simple dorsi flexion of the foot. External pressures cannot come anywhere near the pressure you get with simple dorsi flexion of the foot."
There is a theory that compression therapy will help break down a fibrin cuff. Various studies have shown that compression stimulates fibrinolytic activity. A recent study using five IPC devices in random sequence indicated that intermittent pneumatic compression is an effective form of treatment for DVT and results in a striking elevation in fibrinolytic activity.1
"We also know that acute deep vein thrombosis is a rather insidious disease," Nowicky says. "Its symptoms are usually not very well-noted. By some studies, 90% of patients with DVT have no physical symptoms like redness, swelling, and pain. Usually they won’t get symptoms unless the thrombus is rather extensive and occluding the blood vessel. There’s no screening for DVT, so most people with it are up and ambulating. This means their intraluminal pressures are higher than pressures you could get with pneumatic devices, so the chances of dislodging a clot with a pneumatic device are almost nonexistent. However, if it did happen, the device would be blamed, so it’s definitely listed by all manufacturers that pneumatic devices are contraindicated until someone can prove otherwise."
Nowicky adds that healing will take a long time if the treatment is just putting dressings on a venous ulcer, and the ulcer may not close. "Compression therapy has been found to be very helpful, whether it’s in the form of pneumatics or bandaging, to treat the underlying problem and allow oxygen and nutrients to get to the tissue and get rid of metabolic waste and carbon dioxide," she says. "Since venous ulcers can be a chronic condition, they have about a 70% recurrence rate. What you try to enforce with patients is that though the current ulcer may close and heal, they have to continue with the program to try to keep the edema down through proper management, including exercise and wearing the appropriate hosiery, so that the condition doesn’t recur."
Reference
1. Comerota AJ, et al. Fibrinolytic effects of intermittent pneumatic compression: Mechanism of enhanced fibrinolysis. Ann Surg 1997; 306-314.
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