Economy-class syndrome presenting as phlegmasia caerulea dolens

Flight Microangiopathy in Medium-to Long-Distance Flights: Prevention of Edema and Microcirculation Alterations with Total Triterpenic Fraction of Centella asiatica

The aim of this study was the evaluation of microcirculatory alterations associated with edema in passengers travelling for more than 3 hours and the study of the effects of TTFCA (total triterpenic fraction of Centella asiatica) on the development of microcirculation alterations and edema, in a prospective, randomized study. Laser Doppler flowmetry (LDF), transcutaneous PO2 and PCO2, rate of ankle swelling (RAS) were used. Subjects were randomized after informed consent into two groups: one control group (no drug or other treatment), and a treatment group (TTFCA 60 mg thrice daily for 2 days before the flight, the day of the flight, and for another day after the flight). Inclusion criteria were age range between 30 and 50, mild-moderate superficial venous disease with varicose veins. Subjects traveled in economy class. In controls there was a progressive increase in CO2, RAS, and edema score and a progressive decrease in flux (RF) and venoarteriolar response with flying time. The variations in all parameters were milder (p > 0.05) in the TTFCA group. RAS and edema were significantly lower in the TTFCA-treated group (p < 0.025). The progressive increase in RAS, PCO2, and the decrease in VAR and O2 were linearly associated with flight time (up to 10 hours). These results are very interesting and indicate an option for patients prone to edema and microcirculation disturbances during long flights.

Prevention of Edema and Flight Microangiopathy with Venoruton ® (HR), (0-[Beta-Hydroxyethyl]Rutosides) in Patients with Varicose Veins

The aim of this open study was the evaluation of the effects of HR (Venoruton®) at a dose of 1 g/day on the prevention and control of flight microangiopathy and edema in subjects with varicose veins and moderate chronic venous insufficiency flying for more than 11 hours. Patients with varicose veins, edema, but without initial skin alterations or complications, were included. Measurements of skin laser Doppler (LDF) resting flux (RF) venoarteriolar response (VAR), ankle swelling (RAS), and edema were made within 12 hours before and within 3 hours after the flights. The resulting edema after the flights was evaluated with a composite edema score (analogue scale line). A group of 20 subjects was treated with HR (1 g/day, starting 2 days before the flight and 1 g for every 12 hours on day of travel). Another group of 18 subjects formed the control group. The length of the flights was between 11 and 13 hours; all seats were in coach class. Fifty patients were enrolled and 38 patients were evaluable at the end of the trial. The 2 groups (treatment and control) were comparable for age and sex distribution. The decrease in RF was significant in both groups with a higher flux at the end of the flight in the HR group (p<0.05). The venoarteriolar response was decreased at the end of the flights; the decrease was lower in the HR group (p<0.05). The increase in RAS and the edema score were significantly lower in the HR group. In conclusion HR is useful for reducing the level of microangiopathy and the increased capillary filtration and in controlling edema in patients with venous disease in long flights. The higher level of flux and VAR and the reduction in edema indicate a positive effect of HR on the microcirculation. This study confirms that HR prophylaxis is effective to control flight microangiopathy associated with edema.

Prevention of Edema in Long Flights with Pycnogenol®

The aim of this study was to evaluate the prevention of edema during long-haul flights with an oral, anti-edema and antithrombotic agent (Pycnogenol®, Horphag, Research Management SA, Geneva, Switzerland) in asymptomatic subjects. The assessment of edema was performed by evaluating an analogue scale, the rate of ankle swelling by strain-gauge derived rate of ankle swelling (RAS), and by assessing the ankle circumference variation. The study included 211 subjects; 169 completed the study (88 in the control group and 81 in the Pycnogenol® group). There were no important differences between the two groups (comparable for age, gender, weight, body mass index, and pattern distribution). The edema score, the RAS, and the circumference at inclusion were also comparable. After the flight in those treated with Pycnogenol®, the edema score was increased only by 17.9% (vs. an increase of 58.3% in the control group) (p<0.05). The RAS, evaluated in 22 subjects in the Pycnogenol® group (age 44.5; SD 8) and in 23 in the control group (age 45; SD 9) was increased on average by 91% in the control group and 36% in the Pycnogenol® group (p<0.05). The variation on circumference at the ankle was 6% in the Pycnogenol® group (11% in the control group; p<0.05). These results indicate a positive effect of Pycnogenol® on edema during long flights when considering subjective and objective data. No unwanted effects were observed.

Trends in management of phlegmasia cerulea dolens

Phlegmasia cerulea dolens (PCD) is a fulminant condition of acute massive venous thrombosis that may result in major amputation or death unless treated in an early phase. Guidelines for treatment are still not clearly documented. As a consequence, physicians might have limited knowledge of this potential life-threatening condition and its clinical course. Therefore, the purpose of this review was to analyze and summarize clinical manifestations and proposed diagnostic approach, factors that affect the outcome of PCD, and the evolution of management and therapeutic options. Underlying malignancy, pulmonary embolism, and PCD severity are the vital factors that predict the outcome of PCD. In the last decades, treatment options have remained largely unchanged. Published evidence shows that advances in minimally invasive techniques have not yet resulted in outcome improvements compared with traditional surgical thrombectomy. Treatment seems to depend on grading the severity of this condition and experience of the surgeon.

Thromboembolic disease and air travel in pregnancy: a survey of advice given by obstetricians

The objective of this study was to document the awareness of risk and the nature of advice given by obstetricians to pregnant women who intend to travel by air and to compare the results with the advice given in an opinion paper of the Royal College of Obstetricians and Gynaecologists. The results were based on a self-completed questionnaire. All registered members of the Royal College of Obstetricians and Gynaecologists comprising 1349 individuals, obtained from a list provided by the RCOG, were invited to participate. An anonymous postal questionnaire was completed by the individuals before publication of the opinion paper of the RCOG. A total of 862 (62%) questionnaires returned, and 690 (51%) were available for analysis; 67% of obstetricians regard flying as being safe throughout pregnancy, 33% only in the 2nd and 3rd trimester. Nearly all obstetricians advised on simple prophylactic measures such as mobilisation, fluid intake and leg exercise. Fifty-three per cent would advise the use of prophylactic aspirin (75 mg), 49% the use of compression stockings; 4% recommended heparinisation; 44% believed this advice to be applicable only for the 2nd and 3rd trimester, while the RCOG emphasises that the risk of developing venous thromboembolism begins in the 1st trimester. Obstetricians as well as other health professionals need to be made aware that advice on air travel in pregnancy needs to start in the 1st trimester. Further research is needed to explore the relevance of the duration of flight when considering the application of thromboprophylactic measures as well as the value and choice of pharmacological treatment such as aspirin and heparin.

Prevention of Venous Thrombosis and Thrombophlebitis in Long-Haul Flights with Pycnogenol®

The aim of this study was to evaluate the occurrence of deep venous thrombosis (DVT) and superficial vein thrombosis (SVT) and its prophylaxis with an oral anti-edema and antithrombotic agent (Pycnogenol®, Horphag, Research Management SA, Geneva, Switzerland) in long-haul flights, in subjects at moderate to high-risk of DVT and SVT. The study pre-included 244 pre-selected subjects; 211 were included (33 were excluded for several reasons due to logistic problems) and 198 completed the study; 13 subjects were lost for follow-up at the end of the flight, all for non-medical problems (i.e., for difficult connections). All subjects were scanned within 90 minutes before the flight and within 2 hours after disembarking. Subjects were supplemented with 100 mg Pycnogenol® per capsule. Treatment subjects received two capsules between 2 and 3 hours before flights with 250 mL of water; two capsules were taken 6 hours later with 250 mL of water and one capsule the next day. The control group received comparable placebo at the same intervals. The flight duration was on average 8 hours and 15 minutes (SD 55 min) (range, 7.45-12.33). In the control group there were five thrombotic events (one DVT and four superficial thromboses) while only nonthrombotic, localized phlebitis was observed in the Pycnogenol®group (5.15% vs. no events; p<0.025). The ITT (intention to treat) analysis detects 13 failures in the control group (eight lost to follow up + five thrombotic events) of 105 subjects (12.4%) vs. five failures (4.7%; all lost, no thrombotic events) in the treatment group (p<0.025). No unwanted effects were observed. In conclusion, this study indicates that Pycnogenol® treatment was effective in decreasing the number of thrombotic events (DVT and SVT) in moderate-to-high risk subjects, during long-haul flights.

Economy class stroke syndrome: case report and review of the literature

OBJECTIVES

Venous thromboembolism associated with travelling, or economy class syndrome, is increasingly recognised as a sequence of long haul flights and so paradoxical cerebral embolism through a patent foramen ovale. Materials and methods. We present a new case of economy class stroke syndrome and review of the literature using MEDLINE search.

RESULTS

Literature review identified 12 additional cases. In most of them, stroke occurred in close approximation with landing of the aircraft following a long-haul flight. Venous thromboembolism was present in 58%, while a patent foramen ovale was diagnosed with contrast echocardiography in all but one case. Our case presented with severe left hemispheric stroke, and significant delay, two days after a long-haul flight.

CONCLUSIONS

The small number of reported cases indicates either the rarity of this entity or unawareness of its existence. The true incidence of this condition remains unknown. However, because of treatment implications such as the need to treat venous thromboembolism or close the patent foramen ovale, clinicians should be aware of this entity.

Prevention of venous thrombosis in long-haul flights with Flite Tabs: the LONFLIT-FLITE randomized, controlled trial

The aim of this study was to evaluate the development of edema, and superficial and deep vein thrombosis (DVT) prophylaxis with an oral profibrinolytic agent (Flite Tabs, 150 mg pinokinase, Aidan, Tempe, AZ, USA) in long-haul flights (7-8 hours), in high-risk subjects. A group of 300 subjects was included; 76 were excluded for several problems including concomitant treatments; 204 were randomized into 2 groups (active treatment or placebo) to evaluate the effects of prophylaxis with Flite Tabs. An exercise program was used in both groups. The femoral, popliteal, tibial, and superficial veins were scanned with ultrasound before and within 90 minutes after flights. Of the included subjects, 92 of 103 controls and 94 of 101 treated subjects completed the study. Dropouts were due to connection problems. Age, gender, and risk distribution were comparable in the groups. In the treatment group, no DVT was observed. In the control group, 5 subjects (5.4%) had a DVT and there were 2 superficial thromboses (7 events in 92 subjects; 7.6%). At inclusion, edema was comparable in the 2 groups. After flights there was an increase in score in controls (+12%) in comparison with a decrease (-15%) in the Flite Tabs group (the difference in variation was statistically significant). Intention-to-treat analysis for thrombotic events shows 18 failures in controls (11 lost to follow-up + 7 thrombotic events) of 92 subjects (19.6%) in comparison with 7 failures (of 94 subjects, equivalent to 7.4%) in the treatment group (p < 0.05). Events were asymptomatic. In conclusion, Flite Tabs were effective in reducing thrombotic events and in controlling edema in high-risk subjects in long flights.

Prevention of Venous Thrombosis with Elastic Stockings During Long-Haul Flights: The LONFLIT 5 JAP Study

The aim of this study was to evaluate deep venous thrombosis (DVT) prophylaxis with specific elastic stockings in longhaul flights (11-13 hours), in high-risk subjects. A group of 300 subjects was included; 76 were excluded for several problems including concomitant treatments; 224 were randomized into two groups (stockings vs. controls) to evaluate prophylaxis with below-knee stockings. An exercise program was used in both groups. Scholl (UK) Flight Socks (14-17 mmHg of pressure at the ankle) were used. DVT was diagnosed with ultrasound scanning. The femoral, popliteal, and tibial veins were scanned before and within 90 minutes after the flights. Of the 205 included subjects, 102 controls and 103 treated subjects completed the study. Drop-outs were due to flight connection problems. Age, gender, and risk distributions were comparable in the two groups. In the treatment group (103 subjects; mean age, 42; SD 9; M:F, 55:48), one limited, distal DVT was observed (0.97%). In the control group (102 subjects; mean age, 42.1; SD 10.3; M:F, 56:46), six subjects (5.8%) had a DVT. There were no superficial thromboses. The difference in DVT incidence is significant (p<0.0025; six times greater in the control group). Intention-to-treat analysis counts 18 failures in the control group (12 lost to follow-up + six thromboses) of 112 subjects (15.8%) versus eight failures (7.3%) in the treatment group (p<0.05). The tolerability of the stockings was very good and there were no complaints or side effects. All events were asymptomatic. Considering these observations, Scholl Flight Socks are effective in reducing the incidence of DVT in high-risk subjects.

Flight microangiopathy on long-haul flights: prevention of edema and microcirculation alterations with Venoruton

The aim of this study was the evaluation of the effects of Venoruton (HR) on the prevention and control of flight microangiopathy and edema in subjects with varicose veins flying for more than 7 hours. A group of 80 patients with varicose veins, edema, and initial skin alterations due to chronic venous hypertension were included. Measurements of skin laser Doppler (LDF) resting flux (RF), PO2 and rate of ankle swelling (RAS), were made before and after the flights (within 2 hours before the flights and within 2 hours after the flights). The length of the flights was between 7 and 9 hours; all seats were in coach class. The two groups (treatment and control) were comparable for age and sex distribution. The variation (decrease) in PO2 was significant in both groups. In subjects treated with HR the decrease in PO2 was smaller (p < 0.05). The decrease in LDF-RF was significant in both groups with a higher flux at the end of the flight in the treated subjects (p < 0.05). The venoarteriolar response was decreased at the end of the flights. The decrease was less evident in the treatment group (p < 0.05). The increase in RAS was significant in the control group while it was limited in the HR group. In conclusion, HR is useful for reducing the increased capillary filtration and in controlling edema in patients with chronic venous disease in long-haul flights. HR is effective to control flight microangiopathy associated with edema.

The LONFLIT4-Venoruton Study: a randomized trial--prophylaxis of flight-edema in venous patients

The aim of this independent study was to evaluate the protective effects, on the development of flight edema, of Venoruton. The study included patients with venous disease traveling in economy in long-haul flights (9 hours). Edema is a relevant aspect of long-haul flights affecting both patients with venous disease and normal subjects. Microcirculatory variations during flights cause a microangiopathy and biochemical and coagulation alterations. This condition may be defined as flight microangiopathy. A group of 203 subjects with chronic venous disease (uncomplicated varicose veins) at low-medium risk for DVT were contacted; 43 subjects were excluded for several nonmedical, travel-related problems or inconvenient evaluation time; the remaining 160 were randomized, after informed consent, into 2 groups to evaluate 2 prophylaxes in 7-8-hour, long-haul flights: The treatment group received Venoruton (hydroxyethyl rutosides) 1 g twice daily for 3 days (2 days before the flight and the day of the flight). The control group received comparable placebo. The edema score was based on the edema tester, ankle circumference, volume measurements, subjective swelling, and discomfort score. Items 1, 4, and 5 are based on an analogue scale line (1 to 10) directly defined by the subjects before and after the flights. Of the 160 included subjects 139 completed the study. Dropouts (21) were due to poor compliance, traveling, and/or connection problems (11 in the control group, 10 in the treatment group). Age and sex distribution were comparable in the 2 groups as were risk factors distributions. The level of edema at inclusion was comparable in the 2 groups of subjects. After the flight there was an average score of 7.2 (sd 2) in the control group, while in the Venoruton group the score was on average 3.2. (sd 1.1) (p < 0.05), 2.25 times lower than in the control group (p < 0.05). In the control group 89% of the subjects had an evident increase in ankle circumference and volume, which was clearly visible at inspection and associated with discomfort. In the Venoruton group edema was clearly present in 12% of subjects (associated with discomfort between 5 and 7 on the analogue scale line) and it was mild-moderate, not associated with symptoms (pain, discomfort between 2 and 4 on the analogue scale line). Therefore, the control of flight edema with Venoruton was clear both considering parametric data (circumference and volume) and nonparametric (analogue scale lines) measurements. The combined evaluation of the edema score is significantly favorable for patients treated with Venoruton. No deep vein thrombosis or superficial vein thrombosis was observed in this study.

The LONFLIT4--Concorde Deep Venous Thrombosis and Edema Study: prevention with travel stockings

BACKGROUND

The LONFLIT1+2 studies have established that in high risk subjects after long flights (> 10 hours) the incidence of deep venous thrombosis (DVT) is between 4% and 6%. The LONFLIT4 study was designed to evaluate the control of edema and DVT in low-medium risk subjects. The aim of this study was to evaluate edema and its control with specific stockings (ankle pressure between 20 and 30 mm Hg) in long-haul flights. The first part of the study included flights lasting 7-8 hours and the second part included flights lasting 11-12 hours. Ultrasound scans were used to assess thrombosis before and after the flights and a composite edema score was used to evaluate edema and swelling. A group of patients with microangiopathy associated to edema (diabetes, venous hypertension, anti-hypertensive treatment) were also included to evaluate the preventive effects of stockings during flight. Part I: DVT evaluation: Of the 74 subjects in the stocking group and 76 in the control group (150), 144 completed the study. Dropouts were due to low compliance or traveling and connection problems. Age and gender distribution were comparable in the 3 groups as was risk factor distribution. In this part of the study there were no DVTs. Edema Evaluation: The level of edema at inclusion was comparable in the two groups of subjects. After the flight there was an average score of 6.9 (1) in the control group. In the stocking group, the score was on average 2.3 (1), three times lower than in the control group (p < 0.05). Part II: DVT evaluation: Of the 66 included subjects in the stocking group and 68 in the control group (134), 132 completed the study. Dropouts were due to low compliance or connection problems. Age and gender distribution were comparable in the two groups. In the stocking group no DVT was observed. In the control group, 2 subjects had a popliteal DVT and 2 subjects had superficial venous thrombosis (SVT); in total 4 subjects (6%) in the control group had a thrombotic event; the incidence of DVT was 3%. The difference (p < 0.02) is significant.

EDEMA EVALUATION

The composite edema score at inclusion was comparable in the two groups. After the flight there was a score of 7.94 (2) in the control group, while in the treatment group the score was 3.3 (1.2).

MICROANGIOPATHY STUDY

In all these subjects, the level of edema was very high in the control group and significantly lower in the compression stocking group. Stockings are effective in controlling edema during flights even in subjects with microangiopathy and edema. Compression was well tolerated in normal subjects and in patients.

CONCLUSION

The Kendall Travel Socks (Tyco Healthcare, Mansfield, MA, USA) which provide 20-30 mm Hg pressure at the ankle, are effective in controlling edema and reducing the incidence of DVT in both low-medium-risk subjects and in patients with microangiopathy and edema in long-haul flights (7-11 hours).

The LONFLIT4-Concorde--Sigvaris Traveno Stockings in Long Flights (EcoTraS) Study: a randomized trial

The LONFLIT1/2 studies have established that in high-risk subjects after long ( > 10 hours) flights the incidence of deep venous thrombosis (DVT) may be between 4% and 6%. The LONFLIT4 study was aimed at evaluating the control of edema and DVT prevention in low-medium-risk subjects. In this study prophylaxis of edema with specific travel stockings was evaluated in 2 separate studies involving flights lasting 7 hours and 10-12 hours. Part I. Subjects at low-medium risk for DVT were contacted; 55 subjects were excluded for several nonmedical, travel-related problems or inconvenient evaluation time; the remaining 211 were randomized into 2 groups to evaluate prophylaxis with elastic stockings in 7-8-hour, long-haul flights. The control group had no prophylaxis; the treatment group used below-knee, Sigvaris Traveno elastic stockings (Ganzoni, Switzerland, producing 12-18 mm Hg of pressure at the ankle). Color duplex scanning was used to evaluate the possible presence of DVT; edema/swelling were evaluated with a composite score including the presence of edema (with an edema tester), variations in ankle circumference and leg volumetry, subjective swelling, and discomfort (scale ranging from 0 to 10).

RESULTS

Of the 103 included subjects in the stockings group and 108 in the control group (total 211), 195 subjects completed the study. Dropouts (16) were due to low compliance or traveling and connection problems. Age, sex distribution, and risk factors distributions were comparable in the 2 groups. Stockings Group: Of 97 subjects none had DVT or superficial thromboses.

CONTROL GROUP

Of 98 subjects none had thrombosis. The level of edema at inclusion was comparable in the 2 groups of subjects. After flights there was an average score of 6.4 (1.3) in the control group, while in the stockings group the score was on average 2.4 (SD 1), 2.6 times lower than in the control group (p < 0.05). In the control group 83% of the subjects had an evident increase in ankle circumference and volume that was visible at inspection and associated with discomfort. The control of edema with stockings was clear, considering both parametric data (circumference and volume) and nonparametric (analogue scale lines) measurements. Part II. In this part of the study 200 subjects at low-medium risk for DVT were contacted; 35 subjects were excluded for several nonmedical, travel-related problems or inconvenient evaluation time; the remaining 165 were randomized into 2 groups to evaluate prevention in flights lasting between 11 and 12 hours. The control group had no prophylaxis; the treatment group used Traveno stockings. Of the 83 included subjects in the stockings group and 82 in the control group (total 165), 146 subjects completed the study. Dropouts were due to low compliance or connection problems. Age/sex distribution were comparable. Of 75 subjects completing the study in the stockings group and 71 in the control group, none had thrombosis. The average level of edema at inclusion was comparable in the 2 groups (1.1). After the flight there was a score of 8.9 (2) in controls; in the stockings group the score was 2.56 (1.3) (p < 0.05). The control of edema and swelling with stockings even after 11 hours of flight was clear, considering both parametric (circumference, volume) and nonparametric (analogue scale lines) measurements. The tolerability of the stockings was very good and there were no complaints or side effects. In conclusion Sigvaris Traveno stockings are very effective in controlling edema in long-haul flights.

The LONFLIT4-VENORUTON study: a randomized trial prophylaxis of flight-edema in normal subjects

This study evaluated the protective effects of Venoruton on the development of flight edema in normal subjects travelling in economy in long-haul flights (8-9 hours). Edema is a relevant aspect of long-haul flights affecting both venous patients and normal subjects. Edema and flight microangiopathy were studied in a group of 164 subjects randomized (after informed consent) into two groups to evaluate prophylaxis in 8- to 9-hour flights. The treatment group received Venoruton (hydroxyethyl rutosides) 1 g twice daily for 3 days (2 days before the flight and the day of the flight). The control group received comparable placebo. Edema was evaluated with a composite edema score based on the edema tester, on the measurements of ankle circumference, volume measurements, subjective swelling, and on a discomfort score. Items 1, 4, and 5 are based on an analogue scale line (1 to 10) directly defined by the subjects before and after the flights. Of the included subjects, 151 completed the study. Dropouts were due to poor compliance, travelling, or connection problems. Age and gender distribution were comparable in the two groups as were risk factor distributions. The level of edema at inclusion was comparable in the two groups of subjects. After the flight there was an average score of 6.7 (SD 1.7) in the control group, while in the Venoruton group the score was on average 3 (SD 1.1) (p < 0.05). In the control group 77% of the subjects had an evident increase in ankle circumference and volume, which was clearly visible at inspection and associated with discomfort. In the Venoruton group, edema was clearly present only in 8% of subjects (associated with discomfort rated between 3 and 6 on the analogue scale line) and it was mild, not associated with symptoms. Therefore the control of flight edema with Venoruton was clear both considering parametric data (circumference and volume) and non-parametric (analogue scale lines) measurements. The combined evaluation of the edema score is significantly favorable for subjects under prophylaxis with Venoruton.

Prevention of edema, flight microangiopathy and venous thrombosis in long flights with elastic stockings. A randomized trial: The LONFLIT 4 Concorde Edema-SSL Study

The LONFLIT1/2 studies have established that in high-risk subjects after long (> 10 hours) flights the incidence of deep venous thrombosis (DVT) is between 4% and 6%. The LONFLIT4 study has been planned to evaluate the control of edema and DVT in low-medium-risk subjects. The aim of this study was to evaluate edema and its control with specific flight stockings, in long-haul flights. In the first part of the study 400 subjects at low-medium risk for DVT were contacted; 28 were excluded for several nonmedical problems; 372 were randomized into 2 groups to evaluate prophylaxis with stockings in 7-8-hour flights; the control group had no prophylaxis. Below-knee, Scholl, Flight Socks, producing 14-17 mm Hg of pressure at the ankle, were used in the treatment group. The occurrence of DVT was evaluated with high-resolution ultrasound scanning (femoral, popliteal, and tibial veins). Edema was assessed with a composite score based on parametric and nonparametric measurements. Part II: In this part of the study 285 subjects at low-medium risk for DVT were included and randomized into 2 groups to evaluate edema prophylaxis in 11-12-hour flights; the controls had no prophylaxis while the prevention group had below-knee, Scholl, Flight Socks (comparable to part I).

RESULTS

Part 1: DVT evaluation. Of the 184 included subjects in the stockings group and 188 in the control group, 358 (96.2%) completed the study. Dropouts were due to compliance or connection problems. Age/sex distributions were comparable in the groups. Stockings Group: of 179 subjects (mean age 49; SD 7; M:F = 101:78), none had DVT or superficial thromboses.

CONTROL GROUP

of 179 subjects (mean age 48.4; SD 7.3; M:F = 98:81), 4 (2.2%) had a DVT. There were also 2 superficial thromboses. In total, 3.35% (6) subjects had a thrombotic event. The difference (p<0.002) is significant. Intention-to-treat analysis detects 15 failures in the control group (9 lost + 6 thromboses) out of 188 subjects (7.9%) versus 5 subjects (2.7%) in the stockings group (p <0.05). All thrombotic events were observed in passengers sitting in nonaisle seats. The tolerability of the stockings was very good and there were no complaints or side effects. Thrombotic events were asymptomatic. No difference was observed in the distribution of events between men and women. The 3 women who had a thrombotic event were taking low-dose, oral contraceptives. Edema evaluation: The level of edema at inclusion was comparable in the 2 groups. After the flight there was a score of 6.7 (3.1) in controls; in the stockings group the score was 2.9 times lower (p<0.05). The control of edema with stockings was clear considering both parametric (circumference, volume) and nonparametric (analogue scale lines) data. Part II: DVT evaluation. Of the 285 included subjects, 271 (95%) completed the study. Dropouts were due to low compliance or connection problems. Age/sex distributions were comparable in the groups. Stockings Group: of 142 subjects (mean age 48; SD 8; M:F = 89:53), none had DVT or superficial thromboses.

CONTROL GROUP

of 143 subjects (mean age 47; SD 8; M:F = 87:56), 3 had a popliteal DVT and 3 a superficial thrombosis. In total, 4.2% (6) subjects had a thrombotic event. The difference (p<0.02) between groups is significant. Intention-to-treat analysis detects 14 failures in the control group (8 lost + 6 thromboses = 9.7%) versus 6 (all lost = 4.2% in the stockings group) (p<0.05). Four of 6 events (3 DVT + 1 SVT) were observed in non-aisle seats. The tolerability of the stockings was very good. No difference was observed in the distribution of events between men and women. Edema evaluation: The level of edema at inclusion was comparable in the 2 groups. After the flight there was a score of 8.08 (2.9) in controls while in the stockings group the score was 2.56 (1.5) (p < 0.005). In conclusion. Scholl Flight Socks are very effective in controlling edema. Also this type of compression is effective in significantly reducing the incidence of DVT and thrombotic events in low-medium-risk subjects, in long-haul flights.

CONCLUSIONS

Considering these observations, Flight Socks are effective in controlling edema and in reducing the incidence of DVT in low-medium-risk subjects, in long-haul flights (7-11 hours).

Characteristics of deep vein thrombosis associated with prolonged travel

OBJECTIVES

to identify the incidence of prolonged travel among consecutive patients with deep venous thrombosis (DVT) and to investigate any differences in the patterns of traveller's thrombosis versus DVT's with no history of prolonged recent travel.

METHODS

of 137 consecutive patients, who were confirmed to have DVT by duplex ultrasonography, 36 were excluded because of either prolonged immobilisation or recent surgery. All patients were asked whether they had travelled within 2 weeks for more than 3h. The presence of other classic risk factors for DVT was also recorded. Patients who were unlikely to travel as a result of prolonged immobility for more than 2 weeks and those who underwent surgery within 2 weeks were excluded from the study. The extent and location of thrombi was also verified by duplex scanning in each patient.

RESULTS

of 101 patients, eligible for the final analysis, 15 (15%) claimed to have a recent travel, of whom 9 (9%) travelled by air. By comparison of a group of 106 patients with similar symptoms at presentation, but who had negative duplex finding 12 (11%) had a history of prolonged travel (p=0.8, Fisher's exact test). Travel-related DVT occurred to a significantly younger age group than non travellers. Thirteen (87%) out of 15 patients with travel-related DVT had another coexisting risk factor and 7 out of 10 patients had a positive thrombophilia screen.

CONCLUSION

The majority of those with travel-related DVT had other concomitant risk factors and a high incidence of a positive thrombophilia screen, suggesting that travel itself may act as an additive risk among those with pre-existing risk factors for DVT.

Venous thrombosis from air travel: the LONFLIT3 study--prevention with aspirin vs low-molecular-weight heparin (LMWH) in high-risk subjects: a randomized trial

The LONFLIT1 and 2 studies established that in high-risk subjects after long (>10 hours) flights, the incidence of deep venous thrombosis (DVT) may be between 4% and 6%, The LONFLIT3 study aimed to evaluate methods of prevention in high-risk subjects. Of 467 subjects contacted for the study, 300 were included. These 300 subjects at high risk for DVT were randomized, after informed consent, into three groups: 1) a control group that had no prophylaxis; 2) an aspirin treatment group, in which patients were treated with 400 mg (tablets of oral, soluble aspirin; one dose daily for 3 days, starting 12 hours before the beginning of the flight); and 3) a low-molecular-weight heparin (LMWH) group, in which one dose of enoxaparine was injected between 2 and 4 hours before the flight. The dose was weight-adjusted (1,000 IU [equivalent to 0.1 mL per 10 kg of body weight). Subjects with potential problems due to prophylaxis with aspirin or LMWH or at risk of drug interactions were excluded. Of the 100 included subjects in each group, a total of 249 subjects completed the study (dropouts due to low compliance or traveling/connections problems were 17%). Age and sex distribution were comparable in the three groups as well as risk distributions. Mean age was 47 (range, 28-75; SD, 11; 65% males). Of the 82 subjects in the control group, there were 4.82% of subjects with DVT with two superficial thromboses. In total 4.8% of limbs suffered a thrombotic event. Of 84 subjects in the aspirin treatment group, there were 3.6% of patients with DVT and three superficial thrombosis. In total 3.6% of limbs had a thrombotic event. In the LMWH group (82 subjects), there were no cases of DVT. One superficial thrombosis was documented. In total only 0.6% of limbs had a thrombotic event (p<0.002 in comparison with the other two groups). DVT was asymptomatic in 60% of subjects; 85% of DVTs were observed in passengers in non-aisle seats. Mild gastrointestinal symptoms were reported in 13% of patients taking aspirin. One dose of LMWH is an important option to consider in high-risk subjects during long-haul flights.

Flight microangiopathy in medium-to-long distance flights: prevention of edema and microcirculation alterations with HR (Paroven, Venoruton; 0-(beta-hydroxyethyl)-rutosides): a prospective, randomized, controlled trial

This study evaluated the effects of HR (Paroven, Venoruton; 0-(beta-hydroxyethyl)-rutosides) on the prevention and control of flight microangiopathy, and particularly on edema, in subjects with varicose veins flying for more than 7 hours. Forty patients with varicose veins, edema, and initial skin alterations due to chronic venous hypertension were included. Measurements of skin laser Doppler flowmetry resting flux, Po(2) and rate of ankle swelling, were made before and after the flights (within 4 hours before the flights and within 2 hours after the flights). The length of the flights was between 7 and 9 hours; all seats were in coach class. The 2 groups were comparable for distribution. The variation of Po(2) was significant in both groups. However, in subjects treated with HR, the decrease in Po(2) was smaller (P < 0.05). The decrease in laser Doppler flowmetry resting flux was also significant in both groups, with a higher flux at the end of the control period in the treated subjects (P < 0.05). The venoarteriolar response progressively decreased at 7 and 9 hours. The decrease was less evident in the treatment group (P < 0.05). The rate of ankle swelling was progressively increased in the control group; the increase was not significant in the HR group. In long-haul flights, HR is useful for reducing the increased capillary filtration and in controlling edema in patients with venous hypertension and is effective in controlling perfusion disorders and microangiopathy, particularly swelling and edema, due to flights.

"Long haul" flight and deep vein thrombosis: a model to help investigate the benefit of aspirin and below-knee compression stockings

OBJECTIVE

to develop a model simulating factors of "long haul" flight to investigate the relationship with DVT.

MATERIALS AND METHODS

volunteers (19 males: 20 females) sat for 6 h in a warm (>25 degrees C), dry environment, limited in movement, consuming alcohol (40 ml of 40% alcohol/hour) and salted foods (300 g). Half of the subjects received 150 mg aspirin and wore especially designed below-knee, compression stockings (Class 1 profile). Changes in full blood counts were recorded, and as an indication of DVT formation, plasma was analysed for D-dimer. Limb swelling was assessed from leg measurements.

RESULTS

after 6 h, in controls, there were significant rises in platelet packing (Pct p<0.04), total platelet numbers (p<0.003) and total numbers of white blood cells (WBC's p<0.001). With aspirin plus stockings, there were similar significant rises in total platelet numbers (p<0.002) and total WBC's (p<0.001). In both groups, significant rises were seen in all WBC types (except basophils). Wearing compression stockings prevented calf swelling seen in controls after 6 h (p<0.002). No subject developed a DVT, or a change in levels of D-dimer.

CONCLUSION

changes in the cellular components of blood, particularly WBC's, combined with vaso-compression and reduced flow could predispose towards DVT. Aspirin, combined with compression stockings, may provide prophylaxis.

Venous thromboembolism from air travel: the LONFLIT study

The LONFLIT study was planned to evaluate the incidence of deep venous thrombosis (DVT) occurring as a consequence of long flights. In the Lonflit study 355 subjects at low-risk for DVT and 389 at high-risk were studied. Low-risk subjects had no cardiovascular disease and used no drugs. All flights were in economy class. The average flight duration was 12.4 hours (range, 10-15 hr). The mean age of the studied subjects was 46 years (range 20-80 yr, SD 11; 56% males). DVT diagnosis was made by ultrasound scans after the flights (within 24 hours). In low-risk subjects no events were recorded while in high-risk subjects 11 had DVT (2.8%) with 13 thromboses in 11 subjects and 6 superficial thromboses (total of 19 thrombotic events in 389 patients [4.9%]). In the Lonflit2 study the authors studied 833 subjects (randomized into 422 control subjects and 411 using below-knee stockings). Mean age was 44.8 years (range, 20-80 yr, SD 12; 57% males). The average flight duration was 12.4 hours. Scans were made before and after the flights. In the control group there were 4.5% of subjects with DVT while only 0.24% of subjects had DVT in the stockings group. The difference was significant. The incidence of DVT observed when subjects were wearing stockings was 18.75 times lower than in controls. Long-haul flights are associated to DVT in some 4-5% of high-risk subjects. Below-knee stockings are beneficial in reducing the incidence of DVT.