Growths on bicuspid aortic heart valve. Gross clinical specimen of human bicuspid aortic heart valve showing growths, or vegetation (small nodules). These growths can be caused by bacterial infection. The bacteria grow in vegetative nodules which protect them from immune system responses, so prolonged antibiotic drug therapy is required. Resistant bacteria and late diagnosis can lead to death from heart valve malfunctions and failures. The aortic heart valve (between the left ventricle of the heart and the aorta) usually has three flaps or cusps, but some people are born with 2 cusps, as seen here.