Which of the following procedures is classified as a malabsorptive procedure?

The procedure known as Biliopancreatic Diversion with Duodenal Switch (BPD/DS) is classified as a malabsorptive procedure due to its significant alteration of the digestive process. In this procedure, a large portion of the stomach is removed (similar to sleeve gastrectomy), but it also involves rerouting the intestinal tract, which dramatically reduces the surface area available for nutrient absorption. By bypassing the duodenum and a portion of the small intestine, this procedure leads to decreased absorption of calories and nutrients, which is a key characteristic of malabsorptive procedures.

The other options focus on procedures that primarily induce weight loss through restrictiveness or other mechanisms rather than malabsorption. Sleeve gastrectomy reduces stomach size but does not bypass any segments of the intestine, thus preserving nutrient absorption capability. Laparoscopic Adjustable Gastric Banding involves placing a band around the upper portion of the stomach to restrict food intake without altering the intestinal tract, meaning it does not have a malabsorptive effect.

In summary, the BPD/DS procedure is unique among the listed options for its malabsorptive nature, making it the correct choice.