A number of underlying Gastropathies & G/I conditions are associated with enlarged/prominent gastric folds, such as Chronic Gastritis (most common), Benign tumors, Lymphoid hyperplasia and Gastric malignancy.
Such impressions are frequently associated with H. pylori infection, which should be ruled out!
The cardiac level is likely in ref. to the cardiac orifice of the stomach at the side of the body of the 11th thoracic vertebra, however, it's best to discuss this with the clinician whose name appears on the report, for verification purposes.
I hope this helps.