In adults, three conditions are known to cause aortic stenosis. 1  Progressive wear and tear of a bicuspid valve present since birth (congenital). 2  Wear and tear of the aortic valve in the elderly. 3  Scarring of the aortic valve due to rheumatic fever as a child or young adult.ver time, excessive wear and tear leads to calcification, scarring, and reduced mobility of the valve leaflets. About 10% of bicuspid valves become significantly narrowed, resulting in the symptoms and heart problems of aortic stenosis.
Comma Splice Example. Comma splice is a common mistake made by most people who write in the English language. Here, we try to understand what a comma splice is with the help of a few examples. Take a look.
This last type of compound sentence is the one we will concentrate on for comma use. A compound sentence must have two independent clauses  not just two verbs, two nouns, or two groups of words that are not independent clauses. Look at this example. In the above example, two verb groups are being joined by and.