TABLE 1.

DISTRIBUTION OF EMPHYSEMA AND RESPONSE TO LVRS IN NETT

	Improvement in Exercise Capacity		Improvement in Health-related Quality of Life
	LVRS	Medical	LVRS	Medical
Upper-lobe predominant emphysema on CT
Low Exercise	30%	0%*	48%	10%*
High Exercise	15%	3%*	41%	11%*
Non–upper-lobe predominant emphysema on CT
Low Exercise	12%	7%	37%	7%*
High Exercise	3%	3%	15%	12%

Definition of abbreviations: CT = computed tomography; LVRS = lung volume reduction surgery; NETT = National Emphysema Treatment Trial.

Response of patient to LVRS in the NETT. Improvement in exercise capacity is measured by cardiopulmonary exercise testing; the percentages represent the proportion of patients with a 10-watt improvement over prerandomization baseline in maximal workload attained on cycle ergometry. Improvement in health-related quality of life is measured with the St. George's Respiratory Questionnaire (SGRQ); the percentages represent the proportion of patients with an 8-point decrease (twice the MCID for improvement) in SGRQ score. Table adapted from Reference 7.

^*P ⩽ 0.001 in comparison of LVRS with Medical.