Table 2.

Relationship between cryptogenic stroke and PFO in young and old patients (case-controls studies from 1988 to 2006)

Study	Number of patients (n)	Age of patients (years)	PFO (cryptogenic) (%)	PFO (controls) (%)	P
Prevalence of PFO in young patients
Lechat[35]	26	<55	54 (14/26)	10 (10/100)	<0.001
Webster[36]	34	<40	56 (19/34)	15 (6/40)	<0.001
Cabanes[37]	64	<55	56 (36/64)	18 (9/50)	<0.001
De Belder[38]	39	<55	13 (5/39)	3 (1/39)	—
Di Tullio[39]	21	<55	47 (10/21)	4 (1/24)	<0.001
Hausmann[40]	18	<40	50 (9/18)	11 (2/18)	<0.05
Handke[33]	82	<55	44 (36/82)	14 (7/49)	<0.001
Total	284		45 (129/284)	11 (36/320)	<0.001
Prevalence of PFO in old patients
De Belder[38]	64	>55	20 (13/64)	5 (3/56)	<0.001
Di Tullio[39]	24	>55	38 (9/24)	8 (6/77)	<0.001
Hausmann[40]	20	>40	15 (3/20)	23 (23/98)	ns
Jones[41]	57	>50	18 (10/57)	16 (29/183)	ns
Handke[33]	145	>55	28 (41/145)	12 (28/232)	<0.001
Total	310		25 (76/310)	14 (89/646)	<0.001

PFO = Patent foramen ovale