Available online 19 November 2023, 107588

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Lambl excrescences (LEs) were initially described in the mid 1800s during autopsies of human hearts, and their significance and biology have been debated ever since. LEs are typically found on aortic and pulmonary valve (semilunar) cusps. There is debate concerning whether LEs are a significant cause of thromboembolic events, or whether they are harmless growths. However, there have not been many reports discussing LEs, and fewer still that have examined the prevalence and characteristics of LEs in healthy human hearts. Those that have examined LE prevalence have reported a very high incidence of LEs (85 – 90%). Herein, we examine LE prevalence and characteristics (size, location, number) in 403 healthy human hearts across all age groups. We find that the prevalence of LEs in healthy hearts is far lower than previously reported.

Section snippetsINTRODUCTION

First described in 1856 by their namesake, Dr. Vilem Dusan Lambl, Lambl excrescences (LEs) are filiform extensions arising on the closing surface of cardiac valves [3,6,9]. Their pathophysiology is uncertain, but many have considered them “wear-and-tear” lesions resulting from hemodynamic shear stress [9,12]. Importantly, they have been implicated as potential causes for otherwise idiopathic cerebrovascular events [3,7,8,10,12,14,15]. However, the literature discussing LEs is scant, with only a

Specimen Collection

This study examined heart specimens from patients aged 10 – 99 years (210 men and 193 women) (TABLE 1). Heart specimens were retrieved from the Mayo Tissue Registry. All hearts were previously dissected and fixed in 10% neutral buffered formalin. Only hearts from decedents with no heart disease (by ante-mortem clinical history and autopsy findings) were included in this study.

Heart Examination

The semilunar valves were opened with linear incisions made between the anterior and left pulmonary valve cusps and the

Lambl Excrescence Prevalence

LEs were identified in 26.1% of 403 examined hearts. Within these hearts, we found a total of 303 nodule LEs, 77 free edge LEs, and 17 closing edge LEs. A total of 214 LEs were found in 62 (29.5%) male hearts (183 nodule, 4 closing edge, and 27 free edge), including 62 aortic valves and 0 pulmonary valves. A total of 183 LEs were found in 43 (22.3%) female hearts (120 nodule, 13 closing edge, 50 free edge), including 42 aortic valves and 1 pulmonary valve. Overall, the bias towards nodule LEs

Discussion

In this study we report our findings regarding LE characteristics within aortic and pulmonary valve cusps of 403 non-diseased hearts from humans of both sexes, across the human lifespan. Our findings provide an important extension to the sparse literature surrounding the incidence and characteristics of LEs in the normal human population. The current literature surrounding LEs primarily focus on their potential association with cerebrovascular events, but there has not been a recent study

Conclusions

We have conducted an examination of the Lambl excrescence prevalence and characteristics in 403 non-pathologic human hearts. In accordance with prior literature, we did find a strong correlation between LE prevalence and age, supporting the idea that LEs may stem from age-related degeneration of valve cusps. Additionally, our reported prevalence of LEs in non-diseased hearts is far less than previously reported.

Uncited References

[1], [2], [3], [4], [5], [6], [7], [8], [9], [10], [11], [12], [13], [14], [15]

Declaration of Competing Interest

None

Disclosures

The authors have no conflicts of interest or funding to disclose.

Competing Financial Interests

The authors declare no competing financial interests.

Acknowledgements

We would like to acknowledge the Mayo Clinic Tissue Registry for providing the hearts and the Mayo Clinic Department of Clinical Pathology for preparing the hearts for examination.

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