Esophageal strictureSpent caustic: Spent caustic is a waste industrial caustic solution that has become exhausted and is no longer useful (or spent). Spent caustics are made of sodium hydroxide or potassium hydroxide, water, and contaminants.Carotid artery stenosisAfterload: Afterload is the pressure in the wall of the left ventricle during ejection. In other words, it is the end load against which the heart contracts to eject blood.Spinal stenosis: Spinal stenosis is an abnormal narrowing (stenosis) of the spinal canal that may occur in any of the regions of the spine. This narrowing causes a restriction to the spinal canal, resulting in a neurological deficit.Pulmonary artery sling: Pulmonary artery sling is a rare condition in which the left pulmonary artery anomalously originates from a normally positioned right pulmonary artery. The left pulmonary artery then progresses posteriorly over the right main bronchus near its origin from the trachea, traverses between the trachea and the esophagus and enters the left hilum.