. 2007 Jan 17;22(1):107–114. doi: 10.1007/s11606-006-0016-0

Table 3.

Randomized controlled trials, stratified by risk of deep venous thrombosis

Author (ref) year subjects	Intervention	Mean duration air travel	Subjects with DVT*/total subjects						P^†	Standards met^‡
			Control			Intervention
			Proximal	Distal	Total	Proximal	Distal	Total
Air travelers without increased DVT risk^§
Scurr²⁶ 2001 200	Graduated compression stockings 20–30 mmHg at ankle “put on before the start of travel”	16.5 h over 13–32 d	0/100	12/100	12/100	0/100	0/100	0/100	0.0003	2,4,5,6,7
Scurr²⁶ 2001 200		16.5 h over 13–32 d	0.0%	12%	12%	0.0%	0.0%	0.0%	0.0003	2,4,5,6,7
Belcaro²⁷ 2002 657	All subjects: mild leg exercises and hydration recommended	7–8 h	2/179	2/179	4/179	0/179	0/179	0/179	NS	2,3,4,5,6,7,8
	All subjects: mild leg exercises and hydration recommended	7–8 h	1.1%	1.1%	2.2%	0.0%	0.0%	0.0%	NS
	Intervention: graduated compression stockings 20–30 mmHg at ankle applied 2–3 h before flight	11–12 h	3/135	0/135	3/135	0/136	0/136	0/136	NS
		11–12 h	2.2%	2.2%	2.2%	0.0%	0.0%	0.0%	NS
Cesarone²⁸ 2003 282	All subjects: mild leg exercises and hydration recommended	7–8 h	0/72	0/72	0/72	0/72	0/72	0/72	NS	2,3,4,5,6,7,8
	All subjects: mild leg exercises and hydration recommended	7–8 h	0.0%	0.0%	0.0%	0.0%	0.0%	0.0%	NS
	Intervention: graduated compression stockings 14–17 mmHg at ankle applied 3–4 h before flight	11–12 h	2/66	0/66	2/66	0/64	0/64	0/64	NS
		11–12 h	3.0%	0.0%	3.0%	0.0%	0.0%	0.0%	NS
Cesarone²⁹ 2003 376	All subjects: mild leg exercises and hydration recommended	7–8 h	0/98	0/98	0/98	0/97	0/97	0/97	NS	2,3,4,5,6,7,8
	All subjects: mild leg exercises and hydration recommended	7–8 h	0.0%	0.0%	0.0%	0.0%	0.0%	0.0%	NS
	Intervention: graduated compression stockings 12–18 mmHg at ankle applied 3–4 h before flight	11–12 h	0/71	0/71	0/71	0/75	0/75	0/75	NS
		11–12 h	0.0%	0.0%	0.0%	0.0%	0.0%	0.0%	NS
Air travelers with DVT risk factors^∥
Belcaro¹⁸ 2001 833	All subjects: mild leg exercises and hydration recommended	12.4 h	–	–	19/422	–	–	1/411	<0.001	2,3,5,6,7
Belcaro¹⁸ 2001 833	Intervention: graduated compression stockings 25 mmHg at ankle applied 6–10 h before flight	12.4 h	–	–	4.5%	–	–	0.2%	<0.001	2,3,5,6,7
Cesarone³⁰ 2002 249	All subjects: mild leg exercises and hydration recommended	“Long–haul”	–	–	4/82	–	–	3/84	NS	4,5,6,7
	Intervention: 400 mg ASA daily for 3 d, starting 12 h before flight				4.9%	–	–	3.6%	NS
	Intervention: enoxaparin 1 mg/kg injected 2–4 h before flight					–	–	0/82	NS
						–	–	0.0%	NS
Belcaro³¹ 2003 205	All subjects: educational video recommending mild leg exercises and hydration	11.8 h	5/102	1/102	6/102	0/103	1/103	1/103	NS	2,3,4,5,6,7
			4.9%	1.0%	5.9%	0.0%	1.0%	1.0%
	Intervention: graduated compression stockings 14–17 mmHg at ankle applied 3–4 h before flight
Cesarone³² 2003 186	All subjects: educational video recommending mild leg exercises and hydration	7.7 h	–	–	5/92	–	–	0/94	<0.03	2,4,5,6,7
					5.4%			0.0%
	Intervention: Flite Tabs®^¶
Belcaro³³ 2004 211	All subjects: educational video recommending mild leg exercises and hydration	8.25 h	–	–	1/97	–	–	0/101	NS	4,5,6,7
					1.0%			0.0%
	Intervention: Pycnogenol®^¶

DVT deep venous thrombosis, ASA acetylsalicylic acid.

*All subjects had negative lower extremity ultrasounds prior to travel. All diagnoses of DVT were made by lower extremity ultrasonography performed routinely in all subjects after air travel.

^†Fisher’s exact test comparing total DVT rates.

^‡See Appendix for explanation of standards.

^§Generally, patients with history of DVT, obesity, cancer, coagulation disorders, or “serious” illness were excluded from these studies.

^∥Inclusion criteria generally were history of venous thromboembolism (VTE), obesity, cancer, coagulation disorders, limitation of mobility, and varicose veins. Exclusion criteria generally were severe obesity (weight over 90 kg), clinical disorders requiring anticoagulation, and VTE within 6 months.

^¶Flite Tabs® (Aidan, AZ, USA) contain pinokinase and nattokinase, given 2 capsules 2 hours before flight and 2 capsules 6 hours later, or placebo capsules: Pycnogenol® (Horphag Research Management, Geneva, Switzerland) given 100 mg, 2 capsules 2 hours before flight and 2 capsules 6 hours later and 1 capsule the next day, or placebo capsules.