The prevention and treatment of venous thromboembolism with LMWHs and new anticoagulants

Vascular Health and Risk Management

Volumn 5, Issue , 2009, Pages 693-704

  Blann, Andrew D ^a   Khoo, Chee W ^a  

^a UNIVERSITY DEPARTMENT OF MEDICINE   (United Kingdom)

Author keywords

Anticoagulation; Heparin; Thrombosis; Warfarin

Indexed keywords

ACETYLSALICYLIC ACID; ANTICOAGULANT AGENT; APIXABAN; BEMIPARIN; BETRIXABAN; CERTOPARIN; DABIGATRAN ETEXILATE; DALTEPARIN; ENOXAPARIN; FONDAPARINUX; HEPARIN; LOW MOLECULAR WEIGHT HEPARIN; NADROPARIN; PROTON PUMP INHIBITOR; RIVAROXABAN; THROMBIN INHIBITOR; TINZAPARIN; WARFARIN;

ALOPECIA; ANTICOAGULANT THERAPY; BLEEDING; CLINICAL TRIAL; CONTINUOUS INFUSION; DEEP VEIN THROMBOSIS; DOSE RESPONSE; DRUG ABSORPTION; DRUG ACTIVITY; DRUG ANTAGONISM; DRUG BINDING; DRUG BIOAVAILABILITY; DRUG BLOOD LEVEL; DRUG CLEARANCE; DRUG CONTRAINDICATION; DRUG DISTRIBUTION; DRUG DOSE COMPARISON; DRUG DOSE ESCALATION; DRUG EFFICACY; DRUG ELIMINATION; DRUG EXCRETION; DRUG HALF LIFE; DRUG INDICATION; DRUG INTERMITTENT THERAPY; DRUG MECHANISM; DRUG MEGADOSE; DRUG METABOLISM; DRUG SAFETY; DRUG TOLERABILITY; EMBOLISM; FRACTURE; HEART ATRIUM FIBRILLATION; HEPARIN INDUCED THROMBOCYTOPENIA; HIGH RISK PATIENT; HUMAN; HYPERKALEMIA; HYPERSENSITIVITY; HYPOALDOSTERONISM; INJECTION SITE NECROSIS; LIVER TOXICITY; LOW DRUG DOSE; LUNG EMBOLISM; MONOTHERAPY; OSTEOPENIA; OSTEOPOROSIS; PRACTICE GUIDELINE; PRIAPISM; RECOMMENDED DRUG DOSE; REVIEW; RISK FACTOR; SIDE EFFECT; SKIN NECROSIS; STROKE; THROMBOSIS PREVENTION; TREATMENT DURATION; TREATMENT RESPONSE; VENOUS THROMBOEMBOLISM; CHEMICALLY INDUCED DISORDER; FEMALE; MALE; MIDDLE AGED; ORAL DRUG ADMINISTRATION; PATIENT SELECTION; RISK ASSESSMENT; TREATMENT OUTCOME;

ADMINISTRATION, ORAL; ANTICOAGULANTS; FEMALE; HEMORRHAGE; HEPARIN, LOW-MOLECULAR-WEIGHT; HUMANS; MALE; MIDDLE AGED; PATIENT SELECTION; PRACTICE GUIDELINES AS TOPIC; RISK ASSESSMENT; RISK FACTORS; TREATMENT OUTCOME; VENOUS THROMBOEMBOLISM;

EID: 70350733276     PISSN: 11766344     EISSN: 11782048     Source Type: Journal    
DOI: 10.2147/vhrm.s4621     Document Type: Review

References (110)

1. White RH. The epidemiology of venous thromboembolism. Circulation. 2003;107(23 Suppl 1):14-18.
2. Heit JA. Venous thromboembolism: disease burden, outcomes and risk factors. J Thromb Haemost. 2005;3:1611-1617.
3. Anderson FA, Spencer FA. Risk factors for venous thromboembolism. Circulation. 2003;107:I9-I16.
4. Blann AD, Lip GYH. Venous thromboembolism, Br Med J. 2006;332:215-219.
5. Heparin J, Hirsh Heparin. N Engl J Med. 1991;324:1565-1574.
6. Buller HR, Sohne M, Middeldorp S. Treatment of venous thromboembolism. J Thromb Haemost. 2005;3:1554-1560.
7. Turpie AG, Chin BS, Lip GY. Venous thromboembolism: pathophysiology, clinical features and prevention. Br Med J. 2002;325:887-890.
8. Schmidt-Mulheim A. Beitrage zur Kenntnis des peptones under seiner physiologischen Bedeutung. Archiv fur Anatomie und Physiologie Physiologische Abteilung. 1880:33-56.
9. Doyon M. Rapports du foie avec la coagulation du sang. Journal de Physiologie et de Pathologie General. 1912;14:229-240.
10. McLean J. The thromboplastinics action of cephalin. Am J Physiol. 1916;41:250-257.
11. Howell WH. Heparin and anticoagulation. Am J Physiol. 1923;63:434-435.
12. Jorpes JE. The chemistry of heparin. Biochem J. 1935;29:1817-1830.
13. Crafoord C. Preliminary report on post-operative treatment with heparin as a preventative of thrombosis. Acta Chir Scand. 1937;79:407-426.
14. Best CH. Preparation of heparin and its use in the first clinical case. Circulation. 1959;19:79-86.
15. Brinkhous KM, Smith HP, Warner ED, Seegers WH. The inhibition of blood clotting: an unidentified substance which acts in conjunction with heparin to prevent the conversion of prothrombin to thrombin. Am J Physiol. 1939;125:683-687.
16. Beeler D, Rosenberg R, Jordan R. Fractionation of low molecular weight heparin species and the interaction with antithrombin. J Biol Chem. 1979;254:2902-2913.
17. Barrowcliffe TW, Johnson EA, Eggleton CA, Kemball-Cook G, Thorne DP. Anticoagulant activities of high and low molecular weight heparin fractions. Br J Haematol. 1979;41:573-583.
18. Kakkar VV, Djazaeri B, Fok M, Scully MF, Westwick J. Low molecular weight heparin and prevention of postoperative deep vein thrombosis. Br Med J. 1982;284:375-379.
19. Hirsh J, Ofosu F, Buchanan M. Rationale behind the development of low molecular weight heparin derivatives. Semin Thromb Haemost. 1985;11:13-16.
20. Roemisch J, Gray E, Hoffmann JN, Wiedermann CJ. Antithrombin: a new look at the actions of a serine protease inhibitor. Blood Coag Fibrinolysis. 2002;13:657-670.
21. Salzman EW, Rosenberg RD, Smith MH, Lindon JN, Favreau L. Effects of heparin and heparin fractions on platelet aggregation. J Clin Invest. 1980;65:64-73.
22. Blajchman MA, Young E, Ofusu FA. Effects of unfractionated heparin, dermatan sulphate and low molecular weight heparin on vessel wall permeability in rabbits. Ann NY Acad Sci. 1989;556:245-254.
23. Lindahl U, Hook M. Glycosaminoglycans and their binding to biological macromolecules. Ann Rev Biochem. 1978;47:385-417.
24. Cipolle R, Seifert R, Neilan B, Zaske DE, Hasus E. Heparin kinetics: variables related to disposition and dosage. Clin Pharmacol Ther. 1981;29:387-393.
25. Shojania AM, Tetreault J, Turnbull JL. The variations between heparin sensitivity of different lots of activated partial thromboplastin time reagent produced by the same manufacturer. Am J Clin Pathol. 1988;89:19-23.
26. Hyers TM, Agnelli G, Hull RD, et al. Antithrombotic therapy for venous thromboembolic disease. Chest. 2001;119:176S-193S.
27. Turpie AGG, Chin BSP, Lip GYH. Venous thromboembolism: treatment strategies. Br Med J. 2002;325:948-950.
28. Barritt DW, Jordan SC. Anticoagulant drugs in the treatment of pulmonary embolus: a controlled clinical trial. Lancet. 1960;1(7138):1309-1312.
29. Kernohan RJ, Todd C. Heparin therapy in thromboembolic disease. Lancet. 1966;1(7438):621-623.
30. Salzman EW, Deykin D, Shaprio MR, Rosenberg R. Management of heparin therapy: controlled prospective trial. N Engl J Med. 1975;292:1046-1050.
31. Hull RD, Raskob GE, Hirsh J, et al. Continuous intravenous heparin compared with intermittent subcutaneous heparin in the initial treatment of proximal-vein thrombosis. N Engl J Med. 1986;315:1109-1114.
32. Brandjes DPM, Heijboer H, Buller HR, de Rijk M, Jagt H, ten Cate JW. Acenocoumarol and heparin compared with acenocoumarol alone in the initial treatment of proximal vein thrombosis. N Engl J Med. 1992;327:1485-1489.
33. Schulman S, Rhedin AS, Lindmarker P, et al. A comparison of six weeks of oral anticoagulant therapy after a first episode of venous thromboembolism. Duration of anticoagulation trial study group. N Engl J Med. 1995;332:1661-1665.
34. Turpie AG, Hirsch J. Prophylaxis and therapy of venous thromboembolism. CRC Crit Rev Clin Lab Sci. 1979;10:247-274.
35. Gallus A, Jackaman J, Tillett J, Mills W, Wycherley A. Safety and efficacy of warfarin started early after submassive proximal venous thrombosis or pulmonary embolus. Lancet. 1986;2(8519):1293-1296.
36. Weismann RE, Tobin RW. Arterial embolism occurring during systemic heparin therapy. Arch Surg. 1958;76:219-227.
37. Chong BH. Heparin induced thrombocytopenia. J Thromb Haemost. 2003;1:1471-1478.
38. Warkentin TE. Heparin induced thrombocytopenia. A ten year retrospective. Annu Rev Med. 1999;50:129-147.
39. Warkentin TE. Current agents for the treatment of patients with heparin induced thrombocytopenia. Curr Opin Pulm Med. 2002;8:405-412.
40. Xiao Z, Theroux P. Platelet activation with unfractionated heparin at therapeutic concentrations and comparisons with a low molecular weight heparin and with a direct thrombin inhibitor. Circulation. 1998;97:251-256.
41. Yusuf S, Mehta SR, Chrolavicius S, et al. Comparison of fondaparinux and enoxaparin in acute coronary syndromes. N Engl J Med. 2006;354:1464-1476.
42. Warkentin TE, Levine MN, Hirsh J, et al. Heparin-induced thrombocytopenia in patients treated with low molecular weight heparin or unfractionated heparin. N Engl J Med. 1995;332:1330-1335.
43. Squires JW, Pinch LW. Heparin induced spinal fractures. JAMA. 1979;241:2417-2418.
44. Sackler JP, Liu L. Heparin induced osteoporosis. Br J Radiol. 1973;46:458-460.
45. Ginsberg JS, Kowalchuk G, Hirsch J, et al. Heparin effect on bone density. Thromb Haemost. 1990;64:286-289.
46. Edes TE, Sunderrajan EV. Heparin-induced hyperkalaemia. Arch Intern Med. 1985;145:1070-1072.
47. Dukes GE Jr, Sanders SW, Russo J Jr, et al. Transaminase elevations in patients receiving bovine or porcine heparin. Ann Intern Med. 1984;100:646-650.
48. Hirsch J, Dalen JE, Deykin D, Poller L. Heparin: Mechanism of action, pharmacokinetics, dosing considerations, monitoring, efficacy, safety. Chest. 1992;102(Suppl):337S-351S.
49. Turpie AGG. Can we differentiate the low molecular weight heparins? Clin Cardiol. 2000;23(Suppl I):I4-I7.
50. Offord R, Per ry D. Anticoagulation. London, UK: Science Press;2002.
51. Hirsh J, Warkentin TE, Shaughnessy SG, et al. Heparin and low molecular weight heparin. Mechanism of action, pharmacokinetics, dosing, monitoring, efficacy, safety. Chest. 2001;119(Suppl):64S-94S.
52. Lensing AWA, Prins MH, Davidson BL, Hirsh J. Treatment of deep vein thrombosis with low molecular weight heparins. A meta-analysis. Arch Intern Med. 1995;155:601-607.
53. Leizorovicz A, Simonneau G, Decousus H, Boissel JP. Comparison of efficacy and safety of low molecular weight heparins and unfractionated heparin in initial treatment of deep vein thrombosis: a meta analysis. Br Med J. 1994;309:648-651.
54. Siragusa S, Cosmi B, Piovella F, Hirsch J, Ginsberg G. Low molecular weight heparins an unfractionated in the treatment of patients with acute venous thromboembolism. Results of a meta-analysis. Am J Med. 1996;100:269-277.
55. Low-molecular-weight heparin in the treatment of patients with venous thromboembolism. The Columbus Investigators. N Engl J Med. 1997;337:657-662.
56. Simonneau G, Sors H, Charbonnier B, et al; for the THESEE study group. A comparison of low molecular weight heparin with unfractionated heparin for acute pulmonary embolism. N Engl J Med. 1997;337:663-669.
57. Gould MK, Dembitzer AD, Doyle RL, et al. Low molecular weight heparins compared with unfractionated heparin for the treatment of acute deep vein thrombosis: a meta-analysis of randomised controlled trials. Ann Intern Med. 1999;130:800-809.
58. Norrby K. Heparin and angiogenesis: a low-molecular-weight fraction inhibits and a high-molecular-weight fraction stimulates angiogenesis systemically. Haemostasis. 1993;23(Suppl 1):141-149.
59. Själander A, Jansson JH, Bergqvist D, Eriksson H, Carlberg B, Svensson P. Efficacy and safety of anticoagulant prophylaxis to prevent venous thromboembolism in acutely ill medical inpatients: a meta-analysis. J Intern Med. 2008;263:52-60.
60. Levine M, Gent M, Hirsch J, et al. A comparison of low molecular weight heparin administered primarily at home with unfractionated heparin administered in the hospital for proximal deep vein thrombosis. N Engl J Med. 1996;334:677-681.
61. Koopman MMW, Prandoni P, Piovella F, et al. Treatment of venous thrombosis with intravenous unfractionated heparin administered in the hospital as compared with subcutaneous LMWH administered at home. N Engl J Med. 1996;334:682-687.
62. Omran H, Hammerstingl C, Schmidt H, von der Recke G, Paar WD, Lüderitz B. A prospective and randomised comparison off the safety and effects of therapeutic levels of enoxaparin versus unfractionated heparin in chronically anticoagulated patients undergoing elective cardiac catheterisation. Thromb Haemost. 2003;90:267-271.
63. Jackson MR, Clagett GP. Antithrombotic therapy in peripheral arterial occlusive disease. Chest. 2001;119:283S-299S.
64. Lee AY. The role of low molecular weight heparins in the prevention and treatment of venous thromboembolism in cancer patients. Curr Opin Pulm Med. 2003;9:351-355.
65. Lee AY, Levine MN, Baker RI, et al. Low-molecular-weight heparin versus a coumarin for the prevention of recurrent venous thromboembolism in patients with cancer. N Engl J Med. 2003;349:146-153.
66. Khorana AA. The NCCN Clinical Practice Guidelines on Venous Thromboembolic Disease: strategies for improving VTE prophylaxis in hospitalized cancer patients. Oncologist. 2007;12:1361-1370.
67. Levine MN, Lee AY, Kakkar AK. From Trousseau to targeted therapy: New insights and innovations in thrombosis and cancer. J Thromb Haemost. 2003;1:1456-1463.
68. Folsom AR, Cushman M, Tsai MY, et al. A prospective study of venous thromboembolism in relation to factor V Leiden and related factors. Blood. 2002;99:2720-2725.
69. Schulman S. Unresolved issues in anticoagulant therapy. J Thromb Haemost. 2003;1:1464-1470.
70. Knight CJ, Panseart M, Wilson DJ, et al. Increased platelet responsiveness following coronary stenting. Eur Heart J. 1998;19:1239-1248.
71. The British National Formulary. Issue 57. 2009. Available from http://www.bnf.org/. Accessed March 10, 2009.
72. Turpie AG, Bauer KA, Eriksson BI, Lassen MR. Fondaparinux vs enoxaparin for the prevention of venous thromboembolism in major orthopedic surgery: a meta-analysis of 4 randomized double-blind studies. Arch Intern Med. 2002;162:1833-1840.
73. Hirsh J, Guyatt G, Albers GW, et al. Antithrombotic and thrombolytic therapy. American College of Chest Physicians. Evidence-Based Clinical Practice Guidelines (8th Edition). Chest. 2008;133(6 Suppl):71S-109S. Errata in: Chest. 2008;134:473 and Chest. 2008;134:892.
74. British Thoracic Society Standards of Care Committee Pulmonary Embolism Guideline Development Group. British Thoracic Society Standards of Care Committee Pulmonary embolism guideline. Thorax. 2003;58:470-483.
75. The Scottish Intercollegiate Guidelines Network (SIGN). Available from http://www.sign.ac.uk/. Accessed March 10, 2009.
76. Baglin T, Barrowcliffe TW, Cohen A, Greaves M. Guidelines on the use and monitoring of heparin. Br J Haematol. 2006;133:19-34.
77. Royal College of Obstetrics and Gynaecology. Guideline 28. Thromboembolic disease in pregnancy and the puerperium: Acute management. London UK: Royal College of Obstetrics and Gynaecology; 2001. Available from http://www.rcog.org. uk/. Accessed March 10, 2009.
78. Report of the Independent Expert Working Group on the prevention of venous thromboembolism in hospitalized patients. Department of Health. Available from http://www.doh.gov.uk/. Accessed March 10, 2009.
79. National Institute for Health and Clinical Excellence. Guideline 46. VTE: Reducing the risk of VTE (DVT and PE) in in-patients undergoing surgery. 2008. Available from http://www.nice.org.uk/. Accessed March 10, 2009.
80. Tan KT, Lip GY. Fondaparinux. Curr Pharm Des. 2005;11:415-419.
81. Gross PL, Weitz JI. New anticoagulants for treatment of venous thromboembolism. Arterioscler Thromb Vasc Biol. 2008;28:380-386.
82. Crowther MA, Warkentin TE. Bleeding risk and the management of bleeding complications in patients undergoing anticoagulant therapy: focus on new anticoagulant agents. Blood. 2008;111:4871-4879.
83. Hirsh J, O'Donnell M, Eikelboom JW. Beyond unfractionated heparin and warfarin. Circulation. 2007;116:552-560.
84. Khoo CW, Tay KH, Shantsila E, Lip GYH. Novel oral anticoagulants. Int J Clin Pract. 2009;63:630-641.
85. Shantsila E, Lip GY. Apixaban, an oral, direct inhibitor of activated Factor Xa. Curr Opin Investig Drugs. 2008;9:1020-1033.
86. Kakar P, Watson T, Lip GY. Rivaroxaban. Drugs Today. 2007;43:129-136.
87. Stangier J, Rathgen K, Stahle H, Gansser D, Roth W. The pharmacokinetics, pharmacodynamics and tolerability of dabigatran etexilate, a new oral direct thrombin inhibitor, in healthy male subjects. Br J Clin Pharmacol. 2007;64:292-303.
88. Eriksson BI, Dahl OE, Ahnfelt L, et al. Dose escalating safety study of a new oral direct thrombin inhibitor, dabigatran etexilate, in patients undergoing total hip replacement: BISTRO I. J Thromb Haemost. 2004;2:1573-1580.
89. Eriksson BI, Dahl OE, Buller HR, et al; BISTRO II Study Group. A new oral direct thrombin inhibitor, dabigatran etexilate, compared with enoxaparin for prevention of thromboembolic events following total hip or knee replacement: The BISTRO II randomized trial. J Thromb Haemost. 2005;3:103-111.
90. Ezekowitz MD, Reilly PA, Nehmiz G, et al. Dabigatran with or without concomitant aspirin compared with warfarin alone in patients with nonvalvular atrial fibrillation (PETRO Study). Am J Cardiol. 2007;100:1419-1426.
91. Eriksson BI, Dahl OE, Rosencher N, et al; RE-NOVATE Study Group. Dabigatran etexilate versus enoxaparin for prevention of venous thromboembolism after total hip replacement: a randomized, double-blind, non-inferiority trial. Lancet. 2007;370:949-956.
92. Eriksson BI, Dahl OE, Rosencher N, et al; RE-MODEL Study Group. Oral dabigatran etexilate vs. subcutaneous enoxaparin for the prevention of venous thromboembolism after total knee replacement: the RE-MODEL randomized trial. J Thromb Haemost. 2007;5:2178-2185.
93. Ginsberg JS, Davidson BL, et al. RE-MOBILIZE Writing Committee. Oral thrombin inhibitor dabigatran etexilate vs North American enoxaparin regimen for prevention of venous thromboembolism after knee arthroplasty surgery. 2009;24(1):1-9.
94. National Institute for Health and Clinical Excellence. Final appraisal determination. Dabigatran etexilate for the prevention of VTE after hip or knee replacement surgery in adults. 2008. Available from http://www.nice.org.uk/. Accessed March 10, 2009.
95. Eikleboom JE, Weitz JI. Dabigatran etexilate for prevention of venous thromboembolism. Thromb Haemost. 2009;101:doi:10.1160/TH08-10-0708.
96. Kubitza D, Becka M, Voith B, Zuehlsdorf M, Wensing G. Safety, pharmacodynamics, and pharmacokinetics of single doses of BAY59-7939, an oral, direct factor Xa inhibitor. Clin Pharmacol Ther. 2005;78:412-421.
97. Perzborn E, Strassburger J, Wilmen A, et al. In vitro and in vivo studies of the novel antithrombotic agent BAY 59-7939 - an oral, direct factor Xa inhibitor. J Thromb Haemost. 2005;3:514-521.
98. Eriksson BI, Borris LC, Friedman RJ, et al; RECORD1 Study Group. Rivaroxaban versus enoxaparin for thromboprophylaxis after hip arthroplasty. N Engl J Med. 2008;358:2765-2775.
99. Kakkar AK, Brenner B, Dahl OE, et al; RECORD2 Investigators. Extended duration rivaroxaban versus short-term enoxaparin for the prevention of venous thromboembolism after total hip arthroplasty: a double-blind, randomised controlled study. Lancet. 2008;371(9632):31-39.
100. Lassen MR, Ageno W, Borris LC, et al; RECORD3 Investigators. Rivaroxaban versus enoxaparin for thromboprophylaxis after total knee arthroplasty. N Engl J Med. 2008;358:2776-2786.
101. Agnelli G, Gallus A, Goldhaber SZ, et al; the ODIXa-DVT Study Investigators. Treatment of proximal deep-vein thrombosis with the oral direct factor Xa inhibitor rivaroxaban (BAY 59-7939): the ODIXa-DVT study. Circulation. 2007;116:180-187.
102. Buller HR, Lensing AWA, Prins MH, et al; the Einstein-DVT Dose-Ranging Study Investigators. A dose-ranging study evaluating once-daily oral administration of the factor Xa inhibitor rivaroxaban in the treatment of patients with acute symptomatic deep vein thrombosis: the Einstein-DVT Dose-Ranging Study. Blood. 2008;112:2242-2247.
103. National Institute for Health and Clinical Excellence. Final appraisal determination. Rivaroxaban for the prevention of VTE after hip or knee replacement in adults. March 5, 2009. Available from http://www.nice.org.uk/ guidance/index.jsp?action=download&o=43417. Accessed March 10, 2009.
104. Wong PC, Crain EJ, Xin B, et al. Apixaban, an oral, direct and highly selective factor Xa inhibitor: in vitro, antithrombotic and antihemostatic studies. J Thromb Haemost. 2008;6:820-829.
105. Lassen MR, Davidson BL, Gallus A, Pineo G, Ansell J, Deitchman D. The efficacy and safety of apixaban, an oral, direct factor Xa inhibitor, as thromboprophylaxis in patients following total knee replacement. J Thromb Haemost. 2007;5:2368-2375.
106. Buller H, Deitchman D, Prins M, Segers A; Botticelli Investigators. Efficacy and safety of the oral direct factor Xa inhibitor apixaban for symptomatic deep vein thrombosis. The Botticelli DVT dose-ranging study. J Thromb Haemost. 2008;6:1313-1318.
107. Turpie AG, Bauer KA, Davidson BL, et al; EXPERT Study Group. A randomized evaluation of betrixaban, an oral factor Xa inhibitor, for prevention of thromboembolic events after total knee replacement (EXPERT). Thromb Haemost. 2009;101:68-76.
108. National Patients Safety Agency. Patient Safety Alert 18. Actions that can make anticoagulant therapy safer. 2008. Available from: http://www.npsa.nhs. uk/health/alerts. Accessed March 15, 2009.
109. Department of Health. The VTE Implementation Working Group. September 18, 2008. Available from: http://www.dh.gov.uk/en/Publichealth/Healthprotection/ Bloodsafety/DH-082132.
110. Weitz JI, Hirsh J, Samama MM; American College of Chest Physicians. New antithrombotic drugs: American College of Chest Physicians Evidence-Based. Clinical Practice Guidelines (8th Edition). Chest. 2008;133(6 Suppl):234S-256S. Erratum in Chest. 2008;134:473.