Jan Tack, Florencia Carbone; Alessandra Rotondo


Curr Opin Gastroenterol. 2015;31(6):499-505. 

In This Article

Pathophysiological Mechanisms

Pyloric Resistance

Under physiological circumstances, the pylorus is a key regulator of nutrient passage from the stomach into the duodenum.[8] Although pyloric hypertonicity has been implicated in the pathogenesis of gastroparesis, evidence was limited, and technologies to measure pyloric function were cumbersome.[9] The recently developed endoscopic functional luminal imaging probe (EndoFLIP), a catheter-mounted balloon with impedance sensors for measuring balloon diameter, enables measurement of resistance of the pylorus to distension.[10]

Malik et al.[11] used the EndoFLIP to measure pyloric resistance in 54 gastroparesis patients (39 idiopathic, 15 diabetic) during endoscopy. At a 40 ml balloon volume, pyloric diameter did not differ between diabetic and idiopathic gastroparesis, and was not correlated to gastric emptying rate measured by scintigraphy. Symptom intensities of early satiety and postprandial fullness, measured with the Patient's Assessment of GastroIntestinal Symptoms (PAGI-SYM) questionnaire,[12] were inversely correlated to pyloric diameter.[11] However, the lack of a control group is a limitation.

Gourcerol et al.[13] used the EndoFLIP to measure pyloric resistance in 21 healthy controls, 27 gastroparesis patients, and five patients with esophagectomy without pyloroplasty. Fasting pyloric compliance was significantly higher in controls compared with both patient groups. In the patients, fasting pyloric compliance correlated with symptoms as well as quality of life, measured with the Gastrointestinal Quality of Life Index (GIQLI) score. These findings support a pathophysiological role for pyloric resistance in gastroparesis. The 10 patients with the lowest pyloric compliance underwent pneumatic pyloric dilation and reevaluation after 10 days showed improved symptoms, gastric emptying, and GIQLI score.[13] Limitations are the small size of the treated group, short follow-up, and measurement of compliance in the fasting state.

Duodenal Motility

Wireless motility capsule (WMC, Smartpill) was used to study the correlation of gastric and small intestinal motility to the symptom pattern in gastroparesis.[14] In addition to the traditional WMC parameters of gastric retention time and small bowel/colonic transit time, the authors also quantified antral and duodenal contractions from the manometry tracing as area under the curve (AUC) as well as motility index and contraction frequency, respectively, 1 h before and 1 h after emptying from the stomach. The authors found a moderate correlation between symptom severity and duodenal, but not antral AUC (Pearson correlation R = -0.42, P = 0.02). The gastroparesis cardinal symptom index (GCSI)[15] also correlated with the duodenal contraction frequency and the motility index (all R < -0.55, all P < 0.01), indicating that duodenal, rather than antral motility, correlates with symptoms.[14]