On the mechanism of action of pneumatic compression devices: Combined magnetic resonance imaging and duplex ultrasound investigation

Prevention of perioperative venous thromboembolic complications using pneumatic compression cuffs in oral cancer patients in maxillofacial surgery

OBJECTIVES

Venous thromboembolism (VTE) is still considered to be a significant medical issue. Physical measures to prevent perioperative venous thrombosis include early mobilization and intermittent pneumatic compression (IPC). The aim of this study was to evaluate whether IPC can reduce the incidence of postoperative thromboembolic events in patients with oral squamous cell carcinoma (OSCC) undergoing maxillofacial surgery.

MATERIALS AND METHODS

Between March 2020 and May 2021, 75 patients with OSCC who did not receive perioperative prophylaxis using IPC were retrospectively examined to determine the occurrence of postoperative thromboembolism. Accordingly, 79 patients who received perioperative thrombosis prophylaxis using an IPC system as part of surgical tumor therapy from May 2021 to September 2023 were included in the study. The primary outcome measure was the occurrence of postoperative thromboembolism.

RESULTS

In the control group without IPC, thromboembolic events were observed in five out of 75 patients during postoperative hospitalization. In the intervention group, no thromboembolic occurrences were identified among the 79 patients studied (p = 0.02). The mean Caprini score in the control group was 7.72, whereas in the intervention group it averaged 8.30 (p = 0.027).

CONCLUSIONS

The implementation of IPC-devices as supplementary perioperative thrombosis prophylaxis resulted in a notable decrease in postoperative venous thromboembolism (Number Needed to Treat = 15), which is why implementation of the system as a regular part of the clinical routine for perioperative management of OSCC patients can be considered a sensible approach.

CLINICAL RELEVANCE

The use of IPC enhances patient outcomes and may lead to improved postoperative care protocols in this high-risk patient population.

Effect of intermittent pneumatic compression with different inflation pressures on the distal microvascular responses of the foot in people with type 2 diabetes mellitus

Intermittent pneumatic compression (IPC) is commonly used to improve peripheral circulation of the lower extremity. However, its therapeutic dosage for people with type 2 diabetes mellitus (DM) at risk for ulcers is not well established. This study explored the effect of IPC with different inflation pressures on the distal microvascular responses of the foot in people with type 2 DM. Twenty-four subjects with and without DM were recruited. Three IPC protocols with inflation pressures of 60, 90, and 120 mmHg were applied to the foot. The foot skin blood flow (SBF) responses were measured by laser Doppler flowmetry during and after IPC interventions. Results show that all three IPC interventions significantly increased foot SBF of IPC stage in healthy subjects, but only 90 and 120 mmHg IPC significantly improved SBF in diabetic subjects. IPC with 90 and 120 mmHg showed a greater effect than 60 mmHg in both groups, but 120 mmHg IPC was more effective for diabetic subjects. This study demonstrates that 90 and 120 mmHg are effective dosages of IPC for improving blood flow in healthy people, and 120 mmHg IPC may be more suitable for people with type 2 DM.

Intermittent pneumatic compression combined with rehabilitation training improves motor function deficits in patients with acute cerebral infarction

To investigate the effect of intermittent pneumatic compression (IPC) combined with rehabilitation training on patients with acute cerebral infarction and motor impairment, seventy-four patients with acute cerebral infarction and hemiplegia were randomly and equally divided into two groups, the control group and the IPC treatment group. The patients in the control group received conventional drug therapy and rehabilitation training, and the patients in the treatment group received the IPC treatment in addition to the treatment given in the control group. Motor function, the primary outcome, of the two groups was evaluated by Fugl-Meyer motor function scores. The Barthel index assessment scale was used to evaluate the ability to perform activities of daily living of the two groups, as a secondary outcome. All these indicators were collected and compared before treatment and at 7 days, 14 days, and 30 days after treatment. The incidence of adverse reactions associated with treatment was also recorded. At 7, 14, and 30 days after treatment, the Fugl-Meyer scores (27.16 ± 7.37, 33.41 ± 7.16 and 38.72 ± 7.65) and Barthel scores (47.16 ± 7.37, 52.41 ± 7.16, and 56.09 ± 8.32) of the treatment group were also significantly higher than those (23.65 ± 3.11, 26.13 ± 3.25, and 28.75 ± 5.92; 44.15 ± 3.11, 46.63 ± 3.25 and 47.75 ± 4.22) of the control group (all P < 0.05). With the extension of follow-up time, both scores were higher. There were no treatment-related adverse events in either of the two groups of patients during or after treatment. In conclusion, the IPC combined with rehabilitation training can effectively improve motor function deficits, the ability to perform activities of daily living, and quality of life for patients.

Relationship Between Interface Pressures and Pneumatic Cuff Inflation Pressure at Different Assessment Sites of the Lower Limb to Aid Soft Exoskeleton Design

OBJECTIVE

The aim was to develop a means of predicting interface pressure from cuff inflation pressure during circumferential compression at the lower limb, in order to inform the design of soft exoskeletons.

BACKGROUND

Excessive mechanical loading of tissues can cause discomfort and soft tissue injury. Most ergonomic studies on exoskeletons are of interface pressure, but soft exoskeletons apply circumferential pressures similar to tourniquet cuffs by way of cuff inflation pressure. This study details the relationship between interface and cuff inflation pressures for pneumatic tourniquet cuffs.

METHOD

Pneumatic cuffs of different widths were inflated to target pressures on (A) a rigid cylinder, (B) the dominant thigh and calf, and (C) knee of healthy participants standing still. Interface pressures were measured under the cuffs using a pressure-sensing mat. Average interface pressures were then compared to cuff inflation pressures. The influence of cuff width, cuff inflation pressure, and participants' anthropometric data on pressure transmission was assessed.

RESULTS

A strong linear relationship between cuff inflation pressures and interface pressures was observed. Interface pressures were generally higher than cuff inflation pressures. The efficiency of pressure transmission to the lower limb depended on assessment site, adipose tissue thickness, cuff size, cuff inflation pressure, and possibly limb circumference. Regression equations were developed to predict interface pressures at the thigh, calf, and knee.

CONCLUSION

Interface pressures under pneumatic cuffs are influenced by the cuff size, cuff inflation pressure, and tissue compressibility. Predicted interface pressure from cuff inflation pressure and vice versa can be used to aid the design of soft exoskeletons.

Superficial femoral artery blood flow with intermittent pneumatic compression of the lower leg applied during walking exercise and recovery

The purpose of this study was to determine if muscle blood flow during walking exercise and postexercise recovery can be augmented through the application of intermittent compression of the lower legs applied during the diastolic phase of the cardiac cycle. Results from four conditions were assessed: no compression (NoComp), compression during walking (ExComp), compression during postexercise recovery (RecComp), and compression applied throughout (AllComp). Superficial femoral artery (SFA) blood flow was measured (Doppler ultrasound) during rest and postexercise recovery. Mean arterial blood pressure (MAP, finger photoplethysmography) was used to calculate vascular conductance as VC = SFA flow/MAP. Near infrared spectroscopy measured changes in oxygenated (O2Hb) and deoxygenated hemoglobin concentration throughout the test. Compression during exercise increased SFA blood flow measured over the first 15 s of postexercise recovery (AllComp: 532.2 ± 123.1 mL/min; ExComp: 529.8 ± 99.2 mL/min) compared with NoComp (462.3 ± 87.3 mL/min P < 0.05) and corresponded to increased VC (NoComp: 4.7 ± 0.9 mL·min−1·mmHg−1 versus ExComp: 5.5 ± 1.0 mL·min−1·mmHg−1, P < 0.05). Similarly, compression throughout postexercise recovery also resulted in increased SFA flow (AllComp: 190.5 ± 57.1 mL/min; RecComp: 158.7 ± 49.1 mL/min versus NoComp: 108.8 ± 28.5 mL/min, P < 0.05) and vascular conductance. Muscle contractions during exercise reduced total hemoglobin with O2Hb comprising ~57% of the observed reduction. Compression during exercise augmented this reduction ( P < 0.05) with O2HB again comprising ~55% of the reduction. Total hemoglobin was reduced with compression during postexercise recovery ( P < 0.05) with O2Hb accounting for ~40% of this reduction. Results from this study indicate that intermittent compression applied during walking and during postexercise recovery enhanced vascular conductance during exercise and elevated postexercise SFA blood flow and tissue oxygenation during recovery.

NEW & NOTEWORTHY Intermittent compression mimics the mechanical actions of voluntary muscle contraction on venous volume. This study demonstrates that compression applied during the diastolic phase of the cardiac cycle while walking accentuates the actions of the muscle pump resulting in increased immediate postexercise muscle blood flow and vascular conductance. Similarly, compression applied during the recovery period independently increased arterial flow and tissue oxygenation, potentially providing conditions conducive to faster recovery.

Optimal Compression Therapy and Wound Care for Venous Ulcers

Venous leg ulcers remain a major public health issue with significant economic impact. Two main components of the management of patients with venous leg ulcers are compression therapy and wound care. This article addresses principles and specific aspects of compression therapy and focal wound care for patients with venous leg ulcers.

Enhanced muscle blood flow with intermittent pneumatic compression of the lower leg during plantar flexion exercise and recovery

This study tested the hypothesis that intermittent compression of the lower limb would increase blood flow during exercise and postexercise recovery. Data were collected from 12 healthy individuals (8 men) who performed 3 min of standing plantar flexion exercise. The following three conditions were tested: no applied compression (NoComp), compression during the exercise period only (ExComp), and compression during 2 min of standing postexercise recovery. Doppler ultrasound was used to determine superficial femoral artery (SFA) blood flow responses. Mean arterial pressure (MAP) and cardiac stroke volume (SV) were assessed using finger photoplethysmography, with vascular conductance (VC) calculated as VC = SFA flow/MAP. Compared with the NoComp condition, compression resulted in increased MAP during exercise [+3.5 ± 4.1 mmHg (mean ± SD)] but not during postexercise recovery (+1.6 ± 5.9 mmHg). SV increased with compression during both exercise (+4.8 ± 5.1 ml) and recovery (+8.0 ± 6.6 ml) compared with NoComp. There was a greater increase in SFA flow with compression during exercise (+52.1 ± 57.2 ml/min) and during recovery (+58.6 ± 56.7 ml/min). VC immediately following exercise was also significantly greater in the ExComp condition compared with the NoComp condition (+0.57 ± 0.42 ml·min^-1·mmHg^-1), suggesting the observed increase in blood flow during exercise was in part because of changes in VC. Results from this study support the hypothesis that intermittent compression applied during exercise and recovery from exercise results in increased limb blood flow, potentially contributing to changes in exercise performance and recovery. NEW & NOTEWORTHY Blood flow to working skeletal muscle is achieved in part through the rhythmic actions of the skeletal muscle pump. This study demonstrated that the application of intermittent pneumatic compression during the diastolic phase of the cardiac cycle, to mimic the mechanical actions of the muscle pump, accentuates muscle blood flow during exercise and elevates blood flow during the postexercise recovery period. Intermittent compression during and after exercise might have implications for exercise performance and recovery.

A reduced-order model-based study on the effect of intermittent pneumatic compression of limbs on the cardiovascular system

This work investigates the effect that the application of intermittent pneumatic compression to lower limbs has on the cardiovascular system. Intermittent pneumatic compression can be applied to subjects with reduced or null mobility and can be useful for therapeutic purposes in sports recovery, deep vein thrombosis prevention and lymphedema drainage. However, intermittent pneumatic compression performance and the effectiveness are often difficult to predict. This study presents a reduced-order numerical model of the interaction between the cardiovascular system and the intermittent pneumatic compression device. The effect that different intermittent pneumatic compression operating conditions have on the overall circulation is investigated. Our findings confirm (1) that an overall positive effect on hemodynamics can be obtained by properly applying the intermittent pneumatic compression device and (2) that using intermittent pneumatic compression for cardiocirculatory recovery is feasible in subjects affected by lower limb disease.

Investigating the impact of passive external lower limb compression on central and peripheral hemodynamics during exercise

PURPOSE

The objective of this study was to assess the effectiveness of graduated compression socks (GCS) on enhancing muscle blood flow and oxygenation during exercise and recovery in healthy subjects.

METHODS

Twelve healthy volunteers completed a protocol involving baseline, exercise, and recovery periods with and without GCS. Each test was repeated twice to assess repeatability of the results. The applied sock pressure was measured prior to experimentation using a custom pressure sensing system, and modified as necessary using tensor bandages to control the applied load. During each of the experimental phases, blood velocity in the popliteal artery, calf muscle tissue oxygenation, muscle activity, heart rate, blood pressure, cardiac output, and applied pressure from the sock were measured. Popliteal artery diameter was measured during baseline and recovery periods.

RESULTS

The GCS significantly reduced deoxyhemoglobin (HHb) in the leg during baseline (HHb, p = 0.001) and total blood volume and HHb in the leg during exercise (total hemoglobin, p = 0.01; HHb, p = 0.02). However, there were no differences in leg muscle blood flow velocity or any other variables with and without GCS at baseline, exercise, or recovery. Interestingly, it was found that the local applied sock pressure was very sensitive to the sock application process and, furthermore, the pressure varied considerably during exercise.

CONCLUSIONS

No significant changes were observed in measures reflecting oxygen delivery for healthy subjects using GCS during exercise and recovery. Applied sock pressure was carefully controlled, thus eliminating the sock application process as a variable.

Report from the 2013 meeting of the International Compression Club on advances and challenges of compression therapy

The International Compression Club, a collaboration of medical experts and industry representatives, was founded in 2005 to develop consensus reports and recommendations regarding the use of compression therapy in the treatment of acute and chronic vascular disease. During the recent meeting of the International Compression Club, member presentations were focused on the clinical application of intermittent pneumatic compression in different disease scenarios as well as on the use of inelastic and short stretch compression therapy. In addition, several new compression devices and systems were introduced by industry representatives. This article summarizes the presentations and subsequent discussions and provides a description of the new compression therapies presented.

Relationship between medical compression and intramuscular pressure as an explanation of a compression paradox

Background

Using standing magnetic resonance imaging (MRI), we recently showed that medical compression, providing an interface pressure (IP) of 22 mmHg, significantly compressed the deep veins of the leg but not, paradoxically, superficial varicose veins.

Objective

To provide an explanation for this compression paradox by studying the correlation between the IP exerted by medical compression and intramuscular pressure (IMP).

Material and methods

In 10 legs of five healthy subjects, we studied the effects of different IPs on the IMP of the medial gastrocnemius muscle. The IP produced by a cuff manometer was verified by a Picopress® device. The IMP was measured with a 21G needle connected to a manometer. Pressure data were recorded in the prone and standing positions with cuff manometer pressures from 0 to 50 mmHg.

Results

In the prone position, an IP of less than 20 did not significantly change the IMP. On the contrary, a perfect linear correlation with the IMP ( r = 0.99) was observed with an IP from 20 to 50 mmHg. We found the same correlation in the standing position.

Conclusion

We found that an IP of 22 mmHg produced a significant IMP increase from 32 to 54 mmHg, in the standing position. At the same time, the subcutaneous pressure is only provided by the compression device, on healthy subjects. In other words, the subcutaneous pressure plus the IP is only a little higher than 22 mmHg—a pressure which is too low to reduce the caliber of the superficial veins. This is in accordance with our standing MRI 3D anatomical study which showed that, paradoxically, when applying low pressures (IP), the deep veins are compressed while the superficial veins are not.

A model-based method for the design of intermittent pneumatic compression systems acting on humans

Intermittent pneumatic compression is a well-known technique, which can be used for several therapeutic treatments like sports recovery, lymphoedema drainage, deep vein thrombosis prevention or others, which may require very different operating characteristics as regards the desired pressure values and the operating velocity. The performance and the effectiveness of the device are often difficult to predict and must be usually optimized through empirical adjustments. This article presents a general method based on the mathematical modelling of a generic IPC system, aimed at studying and developing such a device with physical and dynamical characteristics suitable for the intended application.

Manual lymphatic drainage in chronic venous disease: A duplex ultrasound study

Objectives

To compare the effect of call-up and reabsorption maneuvers of manual lymphatic drainage on blood flow in femoral vein and great saphenous vein in patients with chronic venous disease and healthy controls.

Methods

Forty-one subjects participated in this study (mean age: 42.68(15.23)), 23 with chronic venous disease (chronic venous disease group) with clinical classification C1–5 of clinical-etiological-anatomical-pathological (CEAP) and 18 healthy subjects (control group). Call-up and reabsorption maneuvers were randomly applied in the medial aspect of the thigh. The cross-sectional areas, as well as the peak and the mean blood flow velocity at femoral vein and great saphenous vein, were assessed by Duplex ultrasound at the baseline and during maneuvers. The venous flow volume changes were calculated.

Results

The venous flow volume in femoral vein and great saphenous vein increased during both manual lymphatic drainage maneuvers and in both groups ( P < 0.05). The two maneuvers had a similar effect on femoral vein and great saphenous vein hemodynamics, and in both the chronic venous disease and control groups. As a result of the call-up maneuver, the flow volume augmentations, as a result of call-up maneuver, decreased with the severity of chronic venous disease in those patients measured by the clinical classification of CEAP ( r = −0.64; P = 0.03).

Conclusions

Manual lymphatic drainage increases the venous blood flow in the lower extremity with a magnitude that is independent from the specific maneuver employed or the presence of chronic venous disease. Therefore, manual lymphatic drainage may be an alternative strategy for the treatment and prevention of venous stasis complications in chronic venous disease.

Stratified meta-analysis of intermittent pneumatic compression of the lower limbs to prevent venous thromboembolism in hospitalized patients

BACKGROUND

Optimal thromboprophylaxis for patients at risk of bleeding remains uncertain. This meta-analysis assessed whether intermittent pneumatic compression (IPC) of the lower limbs was effective in reducing venous thromboembolism and whether combining pharmacological thromboprophylaxis with IPC would enhance its effectiveness.

METHODS AND RESULTS

Two reviewers searched MEDLINE, EMBASE, and the Cochrane controlled trial register (1966-February 2013) for randomized, controlled trials and assessed the outcomes and quality of the trials independently. Trials comparing IPC with pharmacological thromboprophylaxis, thromboembolic deterrent stockings, no prophylaxis, and a combination of IPC and pharmacological thromboprophylaxis were considered. Trials that used IPC <24 hours or compared different types of IPC were excluded. A total of 16 164 hospitalized patients from 70 trials met the inclusion criteria and were subjected to meta-analysis. IPC was more effective than no IPC prophylaxis in reducing deep vein thrombosis (7.3% versus 16.7%; absolute risk reduction, 9.4%; 95% confidence interval [CI], 7.9-10.9; relative risk, 0.43; 95% CI, 0.36-0.52; P<0.01; I(2)=34%) and pulmonary embolism (1.2% versus 2.8%; absolute risk reduction, 1.6%; 95% CI, 0.9-2.3; relative risk, 0.48; 95% CI, 0.33-0.69; P<0.01; I(2)=0%). IPC was also more effective than thromboembolic deterrent stockings in reducing deep vein thrombosis and appeared to be as effective as pharmacological thromboprophylaxis but with a reduced risk of bleeding (relative risk, 0.41; 95% CI, 0.25-0.65; P<0.01; I(2)=0%). Adding pharmacological thromboprophylaxis to IPC further reduced the risk of deep vein thrombosis (relative risk, 0.54; 95% CI, 0.32-0.91; P=0.02; I(2)=0%) compared with IPC alone.

CONCLUSIONS

IPC was effective in reducing venous thromboembolism, and combining pharmacological thromboprophylaxis with IPC was more effective than using IPC alone.

Upper body exercise increases lower extremity venous blood flow in deep venous thrombosis

OBJECTIVE

Sequential compression devices or ambulation prevent deep venous thrombosis (DVT) by enhancing venous blood flow in the lower extremity. However, compression therapy or ambulation may not be possible in patients with lower extremity surgery or trauma. We therefore determined whether upper body exercise increases venous blood flow in the lower extremities as a potential means for preventing DVT.

METHODS

We determined blood volume flow and velocity responses in the common femoral veins to low-intensity (5 W, 75 rpm) upper body cycle ergometry in healthy individuals. Six protocols of single and intermittent bouts of exercise were tested. Upon determination of the most efficacious protocol in these participants, we verified the effects of upper body exercise in patients with acute DVT. Measurements were made before, during, and after exercise using duplex ultrasound imaging.

RESULTS

The study enrolled 15 healthy volunteers (10 men, 5 women; aged 20-40 years) with no history of DVT and 10 patients (aged 31-86 years) with acute DVT. In healthy participants, a single 30-second bout of upper body exercise increased volume flow up to 39% for up to 10 minutes after exercise (P < .05). A single 3-minute bout increased flow to a lesser extent (23% increase; P = .05) for nearly 5 minutes, but a single 1-minute bout did not increase flow. An intermittent protocol of three 30-second bouts of exercise resulted in an increase of 34% to 57% in venous flow (P < .05) for an average increase of 179 ± 53 mL/min. Intermittent 1-minute bouts of exercise tended to increase flow 10% to 40% (P = .06-.08) for an average increase of 149 ± 64 mL/min. Intermittent 3-minute bouts of exercise increased flow 21% to 45% (P < .05) for an average increase of 120 ± 42 mL/min. In patients with acute DVT, the intermittent 30-second upper body exercise protocol increased venous blood flow by 45% to 83% (P < .05) for an average increase of 250 ± 63 mL/min, an effect lasting >13 minutes.

CONCLUSIONS

We report the novel finding that upper body exercise increases lower extremity venous blood flow in healthy volunteers and in acute DVT patients. Three intermittent 30-second bouts of low-intensity upper body exercise elicited the highest response for the least amount of effort and may represent an alternative or adjunct for prophylaxis of DVT in patients with restricted ambulation.

Magnetic resonance venous velocity mapping during intermittent pneumatic compression of the calf and foot

Objective

Assessment and optimization of intermittent pneumatic compression (IPC) devices for prophylaxis of deep vein thrombosis has previously used duplex ultrasound. The aim was to investigate novel magnetic resonance (MR) venous velocity mapping (VM) for IPC research and development.

Methods

Twelve normal subjects were scanned in the supine position using realtime MR VM with sequential foot and calf IPC (120 mmHg) at 1.5 T. Measurements were taken in the popliteal vein at baseline using both cuffs and each cuff individually recording 60 seconds continuously. Temporal resolution was 310 ms per independent image, at 1 ×1 mm spatial resolution.

Results

Peak velocity ( Vp) measurements: baseline, Vp = 2.1 cm/second (range = 1.1–3.5); using both compression cuffs, Vp = 41.5 cm/second (18.0–58.1); calf cuff alone, Vp = 40.6 cm/second (18.1–62.2); foot cuff alone, Vp = 7.9 cm/second (4.2–15.3). Flow volume measurements per compression cycle ( F): baseline, F = 2.3 cm3 (0.5–11.4); both compression cuffs, F = 7.1 cm3 (2.5–24.6); calf cuff only, F = 7.1 cm3 (2.4–24.5); foot cuff only, F = 2.6 cm3 (0.9–10.7). The foot cuff contribution was insignificant when combined with the calf cuff ( P < 0.01). The MR venous VM results were similar to those reported elsewhere using ultrasound.

Conclusion

This novel technique for MR venous VM can measure the realtime variations in venous blood flow during IPC.

MR phase-contrast velocity mapping methods for measuring venous blood velocity in the deep veins of the calf

PURPOSE

To evaluate the feasibility of using un-gated, real-time MRI for venous blood velocity mapping in the calf, comparing an interleaved spiral k-space sequence (ISP) against a standard segmented gradient echo sequence (GRE).

MATERIALS AND METHODS

A flow phantom with a variable flow-rate was scanned using both GRE and ISP sequences for an in vitro comparison. Seven subjects were scanned prone, performing metronome guided breathing, using the (externally triggered) segmented GRE and real-time ISP sequences. The segmented GRE acquisition duration was 2.5 mins (22 guided respiratory cycles) and the ISP sequence ran continuously for 35 s, 4 full guided respiratory cycles. Mean velocity from each of the deep veins was measured and peak mean velocity, peak flow rate and cumulative volume flow over a respiratory cycle compared between sequences.

RESULTS

The two sequences compared well both in vitro and in vivo. The real-time ISP sequence showed short-term variations in mean velocity superimposed on the respiratory induced flow, which were averaged out using the segmented GRE sequence.

CONCLUSION

Real-time ISP provides comparable time-averaged flow results to the standard sequence with additional information on real-time flow variations and so could be used for further investigation into venous blood flow in the lower leg.

Prevention of Deep Vein Thrombosis and Pulmonary Embolism in Patients With Stroke

Venous thromboembolism (VTE), encompassing deep venous thrombosis and pulmonary embolism, is a potentially fatal but preventable complication of stroke. Reported rates of VTE after stroke have decreased over the last four decades, possibly due to the implementation of stroke units, early mobilization and hydration, and increased early use of antiplatelets. Additional means of thromboprophylaxis in stroke include mechanical methods (ie, compression stockings) to prevent venous stasis and medical therapy including antiplatelets, heparins, and heparinoids. Risk of VTE must be balanced by potential risk of hemorrhagic complications from pharmacotherapy. Unfractionated heparin, low-molecular-weight heparin (LMWH), and danaparoid are acceptable options for chemoprophylaxis though none have shown superior efficacy for VTE prevention without an associated increase in major hemorrhage. The efficacy and timing of pharmacological thromboprophylaxis in hemorrhagic stroke are not well defined. Graduated compression stockings are associated with an increased rate of adverse events and are not recommended and intermittent pneumatic compression stockings require further investigation.