A 14-year-old girl presents with acute severe generalised abdominal pain and vomiting. On examination, the left hypochondrium is empty on percussion, and a firm mobile mass is palpable in the left iliac fossa. Abdominal ultrasound reveals an ectopic spleen in the left lower abdomen with the structure marked **B** appearing stretched and twisted at the hilum. On colour Doppler, a characteristic "whirlpool sign" is observed at this location. Which of the following best describes the pathophysiological consequence of the torsion of the structure marked **B**?