Trump underwent vascular testing because of leg swelling: White House

[Igel]

101. Not all that incredibly rare.

https://www.ncbi.nlm.nih.gov/books/NBK430975/

An estimated 10% to 35% of adults have CVI in the US, with 4% of adults aged 65 years or older developing venous ulcers.[3] Results across studies suggest that in the general population, between 1% and 17% of men and 1% and 40% of women may experience chronic venous insufficiency. Furthermore, the prevalence of varicose veins has been reported to range from under 1% to 70%. The variation in these estimations is likely due to the different diagnostic criteria used and the population surveyed.[1] Globally, the prevalence of CVI is higher in industrialized nations (eg, Western Europe and the US) due to more inactive lifestyles.[5]

The prevalence of venous ulcers, a common complication of CVI, in the US ranges from approximately 1% to 3%.[3] Similarly, lower leg ulceration occurs in approximately 1% to 2% of the global adult population and is reported to increase to 3% in patients older than 65.[5] Formation of an ulcer carries a poor prognosis, with 40% of patients developing recurrence despite standard treatment. Management of chronic venous insufficiency accounts for approximately 2% of the US's total healthcare.[11][12]

If those stats are for the general population and prevalence increases with age, it's more common in the oldest 10% than average.