Background and aims-Conventional short term manometry is a valuable tool in the diagnosis of achalasia but the technique may fail to detect intermittent motor events. The aim of this study was to investigate the pattern of lower oesophageal sphincter (LOS) and oesophageal pressures during prolonged recording in patients with achalasia. Methods-Eleven patients with idiopathic achalasia were studied. Prolonged combined oesophageal pH and manometric recordings of the pharynx, LOS, and stomach were performed using a pH glass electrode and a multiple lumen assembly incorporating a Dent sleeve connected to a portable water perfused manometric system. Results-LOS pressure varied during the day. Postprandial LOS pressures were lower than those recorded preprandially (1.2 v 1.8 kPa; p=0.005) and basal LOS pressures were significantly higher during phase III of the migrating motor complex than during the subsequent phase I (3.3 v 1.8 kPa; p=0.028). Complete LOS relaxations were occasionally observed in seven patients (0.48/h). Complete LOS relaxations were longer in duration than incomplete LOS relaxations (10.8 v 2.8 s; p=0.01) and 57% of complete relaxations fulfilled the criteria of a transient LOS relaxation (TLOSR). Complete LOS relaxations were associated with oesophageal pressure waves with higher amplitudes and longer durations. In addition, a higher proportion of these oesophageal pressure waves were spontaneous (55.6% v 0%; p<0.02) and multipeaked (72.7% v 0%). During prolonged manometry, high amplitude oesophageal pressure waves (>10 kPa) were recorded in six patients and retrograde oesophageal pressure waves in four, phenomena which were not observed during short term manometry. Conclusion-In contrast with short term stationary manometry, prolonged manometry in achalasia patients revealed the occurrence of complete LOS relaxations, TLOSRs, variations in LOS pressure associated with a meal or phase III, and high amplitude and retrograde oesophageal pressure waves. (Gut 2001;49:813-821) Keywords: achalasia; lower oesophageal sphincter; manometry; oesophagus Achalasia is a rare primary neurogenic motility disorder of the oesophagus and lower oesophageal sphincter (LOS) with dysfunction of the inhibitory innervation as the most prominent feature.1 Neuropathological findings in the oesophagus and LOS of achalasia patients include degeneration and reduction of ganglion cells within the myenteric plexus, reduction of vasoactive intestinal polypeptide and nitric oxide nerve fibres in the myenteric plexus, and degenerative lesions of the vagal nerves and the dorsal motor nucleus of the vagal nerve.2-7 These neuronal abnormalities are associated with non-specific changes in oesophageal smooth muscle.
8Short term stationary manometric recording is the gold standard for the diagnosis of achalasia showing absence of peristalsis and incomplete or absent LOS relaxation in response to wet swallows. The simultaneous pressure waves that are seen in the oesophageal body of achalasia patients during conventional manome...