In the Clots in Legs Or Stockings after Stroke 2 (CLOTS-2) trial, proximal deep venous thrombosis (DVT) occurred more often in immobilized stroke patients who wore below-knee compression stockings than their peers who wore thigh-length stockings, according to the study results published online September 20 in Annals of Internal Medicine.
Although whether the CLOTS Trial 2 results should be extrapolated to other patient groups is debatable, but it would seem sensible that thigh-length stockings should be the preferred option and the new standard of care for prevention of deep blood clots.
The longer stockings "should be used as first-line treatment, and below-knee stockings should only be used where the thigh-length ones turn out to be impractical," chief investigator Martin Dennis, MD, of the Division of Clinical Neurosciences, University of Edinburgh, Western General Hospital, in Scotland, was quoted in Medscape Medical News.
The Study Highlights are as follows:
- The study was conducted in 112 international centers between 2002 and 2009. Patients hospitalized for ischemic or hemorrhagic stroke and who were immobile were eligible for study participation, as long as they did not have a subarachnoid hemorrhage, severe peripheral vascular disease, or a sensory neuropathy.
- Participants were randomly assigned to receive either thigh-length or below-knee compression stockings, which were to be worn until hospital discharge, recovery of mobility, death, or hospital day 30. Patients were unblinded to their study treatment.
- Trained ultrasonographers completed lower extremity compression duplex ultrasonography on study subjects between 7 and 10 days after hospital admission. A subset of participants received a second ultrasound study at 25 to 30 days after admission. Researchers attempted to blind ultrasonographers to study treatment.
- The main study outcomes were symptomatic or asymptomatic DVT in the popliteal or femoral veins. Researchers also followed mortality rates and adverse events related to the use of compression stockings.
- 3114 patients underwent randomization, and 75% of patients in both groups fully complied with the randomized treatment protocol. Thigh-length stockings were removed early more frequently than below-knee stockings because of skin complications or patient comfort issues.
- Most baseline data were similar between the thigh-length group and the below-knee stocking group, although the thigh-length stocking cohort had more men and individuals who were independent in their activities of daily living before stroke onset.
- The median delay between stroke onset and study randomization was 2 days.
- Ultrasonographers completed their examinations on 1406 patients (96% of the survivors) in each treatment group at 7 to 10 days and among a total of 1282 patients between 25 to 30 days.
- The incidence rates of DVT among participants with thigh-length and below-knee stockings were 6.3% and 8.8%, respectively, yielding an odds reduction of 31% (95% CI, 9% - 47%). The absolute difference was 2.5 percentage points (95% CI, 0.7 - 4.4 percentage points; P = .008).
- The treatment groups had similar rates of mortality and pulmonary emboli.
- Subgroup analyses failed to alter the main study result.
- Skin complications were more common with thigh-length vs below-knee stockings, but many of these events were mild in nature. However, there was a nonsignificant trend toward a higher rate of skin breaks among participants receiving thigh-length stockings.
- Researchers used previous data to complete an informal analysis comparing below-knee stockings vs usual care. They found a nonsignificant trend toward fewer DVT events among patients not treated with stockings.
