Relationship between Lambl's excrescences and embolic strokes of undetermined source

About one-fourth of ischaemic strokes are classified as embolic strokes of undetermined source. Lambl's excrescences are commonly seen on cardiac valves, and data are limited on whether they may be a source of embolization. We examined the relationship between Lambl's excrescences and embolic stroke of undetermined source.

We performed a case-control study of patients in the Cornell AcutE Stroke Academic Registry. Stroke aetiologies were adjudicated using the Trial of Org 10172 in Acute Stroke Treatment and embolic stroke of undetermined source criteria. We included patients with acute ischaemic stroke between 2011 and 2016 who underwent transthoracic or transoesophageal echocardiography within six months of hospitalisation. Cases were embolic stroke of undetermined source patients and controls were patients with an identified, non-cardioembolic stroke aetiology (i.e. small- or large-vessel strokes). Multiple logistic regression was used to evaluate the association between Lambl's excrescences and embolic stroke of undetermined source after adjustment for demographics, comorbidities and mode of echocardiography.

A total of 923 patients met the criteria for this analysis, including 530 with embolic stroke of undetermined source and 393 with small- or large-vessel strokes. Lambl's excrescences were identified in 47 (8.9%) patients with embolic stroke of undetermined source and 11 (2.8%) patients with small- or large-artery strokes, but the majority (54/58) of Lambl's excrescences were visualised on transoesophageal echocardiogram and embolic stroke of undetermined source patients were more likely to undergo transoesophageal echocardiogram. After adjustment for demographics, comorbidities and mode of echocardiography, we found no association between the presence of Lambl's excrescences and embolic stroke of undetermined source (odds ratio 0.9; 95% confidence interval 0.4-2.3).

We found no association between Lambl's excrescences and embolic stroke of undetermined source. These results do not support the hypothesis that Lambl's excrescences are an occult cause of embolic stroke of undetermined source.