Table 2. Outcomes of NETT study based on distribution of emphysema and exercise capacity.

Parameter	Homogeneous emphysema			Upper-lobe emphysema
	High exercise capacity	Low exercise capacity		High exercise capacity	Low exercise capacity
Mortality	Increased	No change		No change*	Decreased
Exercise capacity	No change	No change		Increased	Increased
Symptoms	No change	Short term improvement		Improved	Improved
FEV1 <20% and DLCO <20% or homogeneous emphysema	Increased mortality

High exercise capacity is defined as >25 W for women and >40 W for men, as measured on post-pulmonary rehab CPET. Exercise capacity defined as a 10 W improvement on CPET. Symptom improvement defined as 8+ change in SGRQ. *, patients with a decreased diffusion capacity in the upper lobes may have a mortality benefit. NETT, National Emphysema Treatment Trial; FEV₁, forced expiratory volume in one second; DLCO, diffusion capacity for the lungs using carbon monoxide; SGRQ, St. George’s respiratory questionnaire; CPET, cardiopulmonary exercise test.