TABLE 2.

Six-minute walk distance (meters) before and after combination therapy

Patient number	BL1	3M	6M	BL2	3M2	6M2
1	240	215	235	235	265	267
2	253	320	420	260	305	255
3	300	370	430	440	386	425
4	280	205	240	220	245	235
5	273	273	495	495	580	600
6	498	520	490	460	480	440
7	220	300	260	260	360	400
8	560	560	400	440	504	546
9	120	306	306	320	385	415
10	400	480	440	260	425	435
Mean	314.40	354.90	371.60	339.00	393.50	401.80
± SD	133.53	124.98	101.77	107.21	107.04	120.60
± SE	42.23	39.52	32.18	33.90	33.85	38.14

BL1 Baseline 1 (before bosentan initiation); BL2 Baseline 2 (before initiation of bosentan plus sildenafil therapy); 3M Three months postinitiation of bosentan treatment; 3M2 Three months postinitiation of bosentan plus sildenafil treatment; 6M Six months postinitiation of bosentan treatment; 6M2 Six months postinitiation of bosentan plus sildenafil treatment