Table 3.

Effect of alteplase on the development of symptomatic infarct swelling by change in HAS between baseline and follow-up

Baseline HAS	Changes in HAS at follow-up	Alteplase n/N*	Control n/N*	Effect of alteplase on development of infarct swelling, OR (95% CI)	P value for interaction
Presence (n=673)	Persistent (n=324)	28/152	18/172	1.93 (1.02 to 3.66)	0.62; d.f.=1
	Disappeared (n=349)	9/198	5/151	1.39 (0.46 to 4.24)
	Subtotal	37/350	23/323	1.54 (0.89 to 2.66)
Absence (n=2057)	Newly developed (n=196)	8/90	5/106	1.97 (0.62 to 6.25)	0.98; d.f.=1
	None (n=1861)	21/957	10/904	2.01 (0.94 to 4.28)
	Subtotal	29/1047	15/1010	1.89 (1.01 to 3.55)
Total	NA	66/1397	38/1333	1.69 (1.13 to 2.54)	0.96; d.f.=3

*N or n=number of patients in each subgroup of morphological changes in HAS presence, n/N: n=number of patients with infarct swelling.

d.f., degree of freedom; HAS, hyperdense artery sign; NA, not applicable.