`
`Downloaded from nejm.org on August 5, 2016. For personal use only. No other uses without permission.
`
` Copyright © 1993 Massachusetts Medical Society. All rights reserved.
`
`WCK1043
`Page 1
`
`
`
`The New England Journal of Medicine
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`Downloaded from nejm.org on August 5, 2016. For personal use only. No other uses without permission.
`
` Copyright © 1993 Massachusetts Medical Society. All rights reserved.
`
`WCK1043
`Page 2
`
`
`
`The New England Journal of Medicine
`
`Downloaded from nejm.org on August 5, 2016. For personal use only. No other uses without permission.
`
` Copyright © 1993 Massachusetts Medical Society. All rights reserved.
`
`WCK1043
`Page 3
`
`
`
`The New England Journal of Medicine
`
`Downloaded from nejm.org on August 5, 2016. For personal use only. No other uses without permission.
`
` Copyright © 1993 Massachusetts Medical Society. All rights reserved.
`
`WCK1043
`Page 4
`
`
`
`The New England Journal of Medicine
`
`Downloaded from nejm.org on August 5, 2016. For personal use only. No other uses without permission.
`
` Copyright © 1993 Massachusetts Medical Society. All rights reserved.
`
`WCK1043
`Page 5