Functional aspects of distal oesophageal spasm: the role of onset velocity and contraction amplitude on bolus transit.

Background: Distal oesophageal spasm is a rare and under-investigated motility abnormality. Recent studies indicate effective bolus transit in varying percentages of distal oesophageal spasm patients. Aim: Explore functional aspects including contraction onset velocity and contraction amplitude cut-off values for simultaneous contractions to predict complete bolus transit. Methods: We re-examined data from 107 impedance-manometry recordings with a diagnosis of distal oesophageal spasm. Receiver operating characteristic analysis was conducted, regarding effects of onset velocity on bolus transit taking into account distal oesophageal amplitude and correcting for intra-individual repeated measures. Results: Mean area under the receiver operating characteristic curve for saline and viscous swallows were 0.84 +/- 0.05 and 0.84 +/- 0.04, respectively. Velocity criteria of >30 cm/s when distal oesophageal amplitude >100 mmHg and 8 cm/s when distal oesophageal amplitude <100 mmHg for saline and 32 cm/s when distal oesophageal amplitude > 100 mmHg and >7 cm/s when distal oesophageal amplitude <100 mmHg for viscous had a sensitivity of 75% and specificity of 80% to identify complete bolus transit. Using these criteria, final diagnosis changed in 44.9% of patients. Abnormal bolus transit was observed in 50.9% of newly diagnosed distal oesophageal spasm patients versus 7.5% of patients classified as normal. Distal oesophageal spasm patients with distal oesophageal amplitude >100 mmHg suffered twice as often from chest pain than those with distal oesophageal amplitude <100 mmHg. Conclusion: The proposed velocity cut-offs for diagnosing distal oesophageal spasm improve the ability to identify patients with spasm and abnormal bolus transit.