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Nomenclature and Clinical Staging of Chronic Dysfunction in
Lung Allografts
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Definitions and Recommendations |
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1. The term bronchiolitis obliterans syndrome
will be used to connote graft deterioration secondary to progressive
airways disease for which there is no other cause. It is widely
presumed, but unproved, that this is a manifestation of chronic
rejection |
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2. The term bronchiolitis obliterans
is reserved for histologically proven diagnoses only; the term
bronchiolitis obliterans syndrome does not necessarily require
histologic confirmation |
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3. Spirometric measurements are to be made
with equipment that conforms to the American Thoracic Society standards
for spirometric testing |
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4. FEV1
measurements used for analysis will be made without the use of an
inhaled bronchodilator preceding the study |
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5. Patients must be 3 months or more after
transplantation to be considered evaluable under this system.
However, determination of a baseline value can be made from the data
obtained within the first 3 months |
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6. The baseline value, to which subsequent measures are referred, is
defined as the average of the two previous highest consecutive
measurements being obtained 3 to 6 weeks apart. In some patients,
the baseline value will rise over time, especially in the first
6 to 9 months. The highest baseline achieved is used for all
subsequent measurements |
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7. Patients showing a 20% or greater decline from previous
baseline studies shall be evaluable only after exclusion of conditions
other than deterioration of graft function, such as airway complications,
infections, congestive heart failure, reversible airway reactivity,
and systemic diseases |
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8. Because a universal table for converting the absolute value of
FEV1 to "percent predicted" does
not exist, a fractional decline in the FEV1
should be determined from the absolute values, especially if the
pulmonary function data have been obtained from more than one
center
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9. For the purposes of staging, a significant decline in the
FEV1 will be determined by the average
of two measurements made at least 1 month apart. Patient's
having a single measurement of decline in FEV1
are not evaluable until a second FEV1
measurement is obtained at least 1 month after the initial data
point
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10. Fractional decline in the FEV1 shall
be expressed as the percent of decline from the previously established
baseline. Thus a patient whose previous baseline FEV1
is 2.0 liters, which falls to a value of 1.0 liters
(average of two data points at least 1 month apart), shall be
construed as having had a 50% factional decline in
FEV1. Should this patient's condition
temporarily stabilize at the new value and subsequently show a decline
in the FEV1 to 800 cc, then the patient,
at that point, shall be considered to have suffered a 60%
fractional decline in FEV1 (that is, the
highest previous baseline value is used for all subsequent
calculations)
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11. Within each of the four proposed staging catagories, there will
be an "a" and a "b" subcategory. These relate to
histologic findings on biopsies. The "a" subcatagory shall
be used to designate no pathologic evidence of bonchiolitis
obliterans (or no pathologic material for evaluation). The "b"
subcategory shall be construed to mean that pathologic evidence of
obliterative bronchiolitis has been obtained
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Staging System |
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Clinical Stage |
Grade of Obliterative Bronciolitis Syndrome |
Pathologic Evidence of Obliterative Bronchiolitis |
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FEV1 80% or more of baseline value |
0 (None) |
a = No |
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b = Yes |
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FEV1 66% to 80%
of baseline value |
1 (Mild) |
a = No |
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b = Yes |
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FEV1 51% to 65%
of baseline value |
2 (Moderate) |
a = No |
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b = Yes |
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FEV1 50% or less
of baseline value |
3 (Severe) |
a = No |
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b = Yes |
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Reference
Cooper JD, et al. A working formulation for the
standardization of nomenclature and for clinical staging of chronic
dysfunction in lung allografts.
J Heart Lung Transplantation 1993;12:713-6.
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