Table 1.

Operator and Site Factors versus the Occurrence of a Hemorrhagic or Ischemic Event (n=34)

Factor	# Sites or Operators	# Patients	Hemorrhagic or Ischemic Event
			n(%)	p-value*	Difference (95% CI) †
SAMMPRIS Site Enrollment
High (≥ 12)	12	111	17 (15.3%)	0.85	−1.4% (−11.7% – 8.7%)
Low (< 12)	36	102	17 (16.7%)
High-Enrolling Registry Site
No	38	132	21 (15.9%)	0.99	−0.1% (−11.3% – 9.8%)
Yes	10	81	13 (16.0%)
Primary Specialty of Interventionist
Radiology	39	115	17 (14.8%)	0.28	1: 0.9% (−13.4% – 13.3%)
Neurosurgery	18	72	10 (13.9%)		2: −12.1% (−38.7% – 7.3%)
Neurology	6	26	7 (26.9%)		3: −13.0% (−39.5% – 7.9%)
Credentialing: # Study devices
< 10	30	71	7 (9.9%)	0.11	−9.1% (−18.5% – 2.1%)
≥ 10	33	142	27 (19.0%)
Credentialing: # Aneurysm Stents
< 6	29	116	21 (18.1%)	0.45	4.7% (−5.8% – 14.7%)
≥ 6	34	97	13 (13.4%)
# Years in Practice
< 8	28	104	18 (17.3%)	0.71	2.6% (−7.5% – 12.9%)
≥ 8	35	109	16 (14.7%)
# SAMMPRIS PTAS Cases
< 3	31	43	7 (16.3%)	0.99	0.4% (−10.6% – 15.9%)
≥ 3	32	170	27 (15.9%)

^*P-value for Fisher’s exact test comparing percentages among groups.

^†Difference between percentages, calculated as first group – second group, except for Primary Specialty (1: Radiology – Neurosurgery, 2: Radiology – Neurology, 3: Neurosurgery – Neurology).

^‡Total in both groups exceeds 63 interventionists because individual interventionists had patients in both groups.

PTAS = Percutaneous Transluminal Angioplasty and Stenting, CI = Confidence Interval.