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Abstract Background As previously reported there is evidence for a reduction in right to left shunt (RLS) in stroke patients with patent foramen ovale (PFO). This occurs predominantly in patients with cryptogenic stroke (CS). We therefore analysed factors associated with a shunt reduction on follow-up in stroke patients suffering of CS. Methods On index event PFO and RLS were proven by transesophageal echocardiography and contrast-enhanced transcranial Doppler-sonography (ce-TCD). Silent PE was proved by ventilation perfusion scintigraphy (V/Q) within the stroke work-up on index event; all scans were re-evaluated in a blinded manner by two experts. The RLS was re-assessed on follow-up by ce-TCD. A reduction in shunt volume was defined as a difference of ≥20 microembolic signals (MES) or the lack of evidence of RLS on follow-up. For subsequent analyses patients with CS were considered; parameters such as deep vein thrombosis (DVT) and silent pulmonary embolism (PE) were analysed. Results In 39 PFO patients suffering of a CS the RLS was re-assessed on follow-up. In all patients (n = 39) with CS a V/Q was performed; the median age was 40 years, 24 (61.5%) patients were female. In 27 patients a reduction in RLS was evident. Silent PE was evident in 18/39 patients (46.2%). Factors such as atrial septum aneurysm, DVT or even silent PE were not associated with RLS dynamics. A greater time delay from index event to follow-up assessment was associated with a decrease in shunt volume (median 12 vs. 6 months, p = 0.013). Conclusions In patients with CS a reduction in RLS is not associated with the presence of a venous embolic event such as DVT or silent PE. A greater time delay between the initial and the follow-up investigation increases the likelihood for the detection of a reduction in RLS.

Abstract Background In patients with patent foramen ovale (PFO) there is evidence supporting the hypothesis of a change in right-to-left shunt (RLS) over time. Proven, this could have implications for the care of patients with PFO and a history of stroke. The following study addressed this hypothesis in a cohort of patients with stroke and PFO. Methods The RLS volume assessed during hospitalisation for stroke (index event/T0) was compared with the RLS volume on follow-up (T1) (median time between T0 and T1 was 10 months). In 102 patients with a history of stroke and PFO the RLS volume was re-assessed on follow-up using contrast-enhanced transcranial Doppler/duplex (ce-TCD) ultrasound. A change in RLS volume was defined as a difference of ≥20 microembolic signals (MES) or no evidence of RLS during ce-TCD ultrasound on follow-up. Results There was evidence of a marked reduction in RLS volume in 31/102 patients; in 14/31 patients a PFO was no longer detectable. An index event classified as cryptogenic stroke (P < 0.001; OD = 39.2, 95% confidence interval 6.0 to 258.2) and the time interval to the follow-up visit (P = 0.03) were independently associated with a change in RLS volume over time. Conclusions RLS volume across a PFO decreases over time, especially in patients with cryptogenic stroke. These may determine the development of new strategies for the management in the secondary stroke prevention.

During the last years, high-resolution ultrasonography of large arteries has significantly contributed to our further understanding of the pathophysiology of obstructive sleep apnoea (OSA)-related cardiovascular disease. Measurements of flow-mediated vasodilation (FMD) of the brachial artery have demonstrated that untreated OSA patients have reduced endothelial-dependent vasodilation, i.e. endothelial dysfunction. This is an established precursor lesion for both arterial hypertension and atherosclerosis. Probably the cause of endothelial dysfunction in OSA is increased oxidative stress with reduced bioavailability of the endothelial-derived vasodilator nitric oxide. Furthermore, it was shown that the reduction in FMD is correlated with the apnoea--hypopnoea index and the degree of nocturnal hypoxia even after adjustment for confounding factors. Effective continuous positive airway pressure (CPAP) therapy leads to an improvement of vasoreactivity in OSA. Measurements of intima-media thickness at the level of the common carotid artery (CCA-IMT) have shown that OSA patients have higher values of this parameter when compared to matched controls without sleep-disordered breathing. CCA-IMT reflects the early stages of atherosclerosis, and increased CCA-IMT is associated with an elevated cardiovascular risk (myocardial infarction and stroke). CCA-IMT is also related to OSA severity, i.e. it increases with the degree of nocturnal hypoxia. It has not yet been investigated whether long-term CPAP therapy leads to a decrease in CCA-IM'E [ABSTRACT FROM AUTHOR]