Small- and Moderate-Size Right-to-Left Shunts Identified by Saline Contrast Echocardiography Are Normal and Unrelated to Migraine Headache

Background: We suspected, based on clinical experience, that the prevalence of both intracardiac and pulmonary arteriovenous malformations (PAVMs) is higher than previously reported in a healthy population when using modern ultrasound technology combined with a rigorous saline contrast echocardiogram (SCE) protocol. NW hypothesized the prevalence of right-to-left shunts (RLSs) would be so high when using this sensitive technique that there would be no significant association of RLS with migraine headache. Methods: We recruited 104 healthy volunteers to undergo an SCE followed by completion of a migraine questionnaire. The SCEs were meticulously graded for shunt size and location based on left-sided heart contrast quantity and timing. The migraine headache questionnaire was graded by a neurologist blinded to SCE results. Results: One hundred four subjects underwent the study protocol. We found 71% of subjects exhibited evidence of RLS. Patent foramen ovate (PFO) was identified in 40 (38%), PAVM was identified in 29 (28%), and five subjects had evidence or both (5%). Based on questionnaires, 42 (40%) of the subjects had migraine headache (29% with aura). There was no significant association of migraine headache with PM (OR, 0.59; 95% CI, 0.16-2.12; P = .54) or PAVM (OR, 0.8; 95% CI, 0.34-1.9; P = .67), although only 13 (13%) of the subjects had evidence of large RLS. Conclusions: When using modern ultrasound technology combined with a rigorous SCE technique, the majority of healthy subjects demonstrate some degree of RLS. PAVM in an otherwise healthy population is common. Small- and moderate-size RLSs do not appear to be significantly associated with migraine headache. CHEST 2010;138(2):264-269