Table 2.

Operator and Site Factors versus the Occurrence of a Hemorrhagic Stroke (n=13)

Factor	# Sites or Operators	# Patients	SAH	ICH	SAH or ICH
			n (%)	n (%)	n (%)	p-value	Difference (95% CI) †
SAMMPRIS Site Enrollment
High (≥ 12)	12	111	1 (0.9%)	2 (1.8%)	3 (2.7%)	0.043	−7.1% (−14.9% – −0.6%)
Low (< 12)	36	102	5 (4.9%)	5 (4.9%)	10 (9.8%)
High Enrolling Registry Site
No	38	132	5 (3.8%)	5 (3.8%)	10 (7.6%)	0.38	3.9% (−4.0% – 10.5%)
Yes	10	81	1 (1.2%)	2 (2.5%)	3 (3.7%)
Primary Specialty of Interventionist
Radiology	39	115	4 (3.5%)	3 (2.6%)	7 (6.1%)	0.071	1: 3.3% (−6.6% – 11.7%)
Neurosurgery	18	72	0 (0%)	2 (2.8%)	2 (2.8%)		2: −9.3% (−34.3% – 4.8%)
Neurology	6	26	2 (7.7%)	2 (7.7%)	4 (15.4%)		3: 12.6% (−37.1% – 1.9%)
Credentialing: # Study devices
< 10	30	71	2 (2.8%)	2 (2.8%)	4 (5.6%)	0.99	−0.7% (−7.3% – 8.1%)
≥ 10	33	142	4 (2.8%)	5 (3.5%)	9 (6.3%)
Credentialing: # Aneurysm Stents
< 6	29	116	3 (2.6%)	4 (3.4%)	7 (6.0%)	0.99	−0.2% (−7.7% – 6.8%)
≥ 6	34	97	3 (3.1%)	3 (3.1%)	6 (6.2%)
# Years in Practice
< 8	28	104	5 (4.8%)	3 (2.9%)	8 (7.7%)	0.40	3.1% (−3.8% – 10.8%)
≥ 8	35	109	1 (0.9%)	4 (3.7%)	5 (4.6%)
# SAMMPRIS PTAS Cases
< 3	31	43	2 (4.7%)	2 (4.7%)	4 (9.3%)	0.40	4.0% (−3.8% – 17.2%)
≥ 3	32	170	4 (2.4%)	5 (2.9%)	9 (5.3%)

^*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, SAH = Subarachnoid Hemorrhage, ICH= Intraparenchymal Hemorrhage, CI = Confidence Interval.