A relationship between the presence of PFO and increased DCI risk is certainly possible.
This work may be of interest to you. I realize that the linked paper is on a mouse model.
Comment: Although the mouse study you linked is suggestive, well controlled studies involving humans seem to show no statistically significant relationship until PFOs of quite substantial size are involved.
1. Circulation. 2010 Mar 30;121(12):1406-12. Epub 2010 Mar 15.
Lack of association between migraine headache and patent foramen ovale: results of a case-control study.
Garg P, Servoss SJ, Wu JC, Bajwa ZH, Selim MH, Dineen A, Kuntz RE, Cook EF, Mauri L.
Division of Cardiology, Brigham and Women's Hospital, Boston, Mass 02115, USA.
Comment in:
Circulation. 2010 Mar 30;121(12):1377-8.
Abstract
BACKGROUND: Clinical observations of migraine headache symptoms in patients with a patent foramen ovale (PFO), both of which conditions are highly prevalent, have raised the question of a possible pathophysiological relationship. We sought to evaluate the assumption of an association between migraine headaches and the presence of PFO by use of a large case-control study.
METHODS AND RESULTS: We conducted a case-control study to assess the prevalence of PFO in subjects with and without migraine. Case subjects were those with a history of migraine (diagnosed by neurologists at a specialty academic headache clinic). Control subjects were healthy volunteers without migraine 1:1 matched on the basis of age and sex with case subjects. Presence of PFO was determined by transthoracic echocardiogram with second harmonic imaging and transcranial Doppler ultrasonography during a standardized procedure of infused agitated saline contrast with or without Valsalva maneuver and a review of the results by experts blinded to case-control status. PFO was considered present if both studies were positive. Odds ratios were calculated with conditional logistic regression in the matched cohort (n=288). In the matched analysis, the prevalence of PFO was similar in case and control subjects (26.4% versus 25.7%; odds ratio 1.04, 95% confidence interval 0.62 to 1.74, P=0.90). There was no difference in PFO prevalence in those with migraine with aura and those without (26.8% versus 26.1%; odds ratio 1.03, 95% confidence interval 0.48 to 2.21, P=0.93).
CONCLUSIONS: We found no association between migraine headaches and the presence of PFO in this large case-control study.
2. Can J Neurol Sci. 2009 Nov;36(6):740-4.
Contrast echocardiography and migraine in divers with patent foramen ovale.
Di Fabio R, Giugni E, Angeloni I, Vanacore N, Casali C, Pierallini A, Vadalà R, Pierelli F.
Department of Neuromotor Rehabilitation, Sapienza University of Rome Polo Pontino-ICOT, Latina, Italy.
rob.dif@tiscali.it
Abstract
BACKGROUND: It has been proposed that the patent foramen ovale (PFO) may be associated with migraine, in particular migraine with aura. However, it is not clear whether paradoxical embolism triggers crises of headache. Cerebral embolization is provoked in subjects with PFO through contrast echocardiography, a safe method to diagnose the presence of foramen ovale pervium.
METHODS: Twenty-four men practicing diving, an activity characterized by increased prevalence of PFO and migraine, underwent trans-thoracic echocardiography with contrast solution, composed of saline and air mixture and checked for the occurrence of migraine in the following 24 hours.
RESULTS: A PFO (five of minimal size, i.e. visible only during Valsalva, one of small and two of medium size) was detected in 8/24 divers (33%). No one reported headache over the 24 hours after the procedure.
DISCUSSION: Our preliminary data suggest that cerebral micro-embolism, provoked by contrast echocardiography, does not systematically trigger migraine crises when a minimal-to-medium sized patent foramen ovale is present.
3. Chest. 2010 Feb 12. [Epub ahead of print]
Small and Moderate Size Right-to-Left Shunts Identified By Saline Contrast Echocardiography Are Normal and Unrelated To Migraine Headache.
Woods TD, Harmann L, Purath T, Ramamurthy S, Subramanian S, Jackson S, Tarima S.
dagger Wheaton-Franciscan Health Care, Racine WI.
Abstract
BACKGROUND: We suspected based on clinical experience that the prevalence of both intracardiac and pulmonary arteriovenous malformations (PAVM) are higher than previously reported in a healthy population when using modern ultrasound technology combined with a rigorous saline contrast echo (SCE) protocol. We hypothesized the prevalence of right-to-left shunts (RLS) would be so high when employing this sensitive technique, there would be no significant association of RLS with migraine headache.
METHODS: We recruited 104 healthy volunteers to undergo a SCE followed by completion of a migraine questionnaire. The SCE were meticulously graded for shunt size and location based on left heart contrast quantity and timing. The migraine headache questionnaire was graded by a neurologist blinded to SCE results.
RESULTS: 104 volunteers underwent the study protocol. We found 71% of volunteers exhibited evidence of RLS. PFO was identified in 40(38%), PAVM in 29 (28%), and 5 subjects had evidence of both (5%). Based on questionnaires, 42 (40%) of the volunteers had migraine headache (29% with aura). There was no significant association of migraine headache with PFO (OR 0.59, 95% CI 0.16-2.12, p=0.54) or PAVM (OR 0.8, 95% CI .34-1.9, p=0.67), although only 13 (13%) of volunteers had evidence of large RLS.
CONCLUSIONS: When using modern ultrasound technology combined with a rigorous SCE technique, the majority of healthy volunteers demonstrate some degree of RLS. PAVM in an otherwise healthy population is common. Small and moderate size RLS do not appear to be significantly associated with migraine headache.
4. Curr Pain Headache Rep. 2009 Jun;13(3):221-6.
Patent foramen ovale and migraine: association, causation, and implications of clinical trials.
Tepper SJ, Cleves C, Taylor FR.
Center for Headache and Pain, Neurological Institute, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195, USA.
teppers@ccf.org
Abstract
Patent foramen ovale (PFO) appears to be associated with migraine with aura (MA), probably through cardiac shunting. PFOs may also be comorbid with cryptogenic strokes. Although multiple open-label, retrospective, and case-controlled studies have noted sometimes dramatic reductions of MA after PFO closure, the only prospective sham-controlled study of PFO closure for MA, MIST, was negative for all primary and secondary measures of migraine improvement. MIST did demonstrate an association between MA and severe PFO shunts prospectively. Difficulty with recruitment closed the MIST II and ESCAPE trials; the PREMIUM and PRIMA randomized controlled trials are ongoing at the time of this writing.
Regards,
DocVikingo
