Table 1.

 Description of the patient population

		n	Age (mean) (years)	Female (%)	Primary angioplasty (%)	Referral hospital (%)
A	Respondents	103	60	25	52	71
	Non-respondents	22	68*	23	50	59
B	Respondents	78	61	30	0	89
	Non-respondents	44	64	34	0	80

*Difference in mean age between respondents and non-respondents was significant (Student’s t test: p = 0.029; 95% confidence interval 0.8 to 13.8).

A, patients who participated in the trial; B, patients who did not participate in the trial.