Comparison of High Resolution Pressure Topography and High Resolution Impedance Manometry in Patients With Non-obstructive Dysphagia

Abstract

Introduction: High resolution pressure topography (HRPT) facilitates better characterization of esophageal peristalsis than conventional waveforms (CW), including recognition of ineffective esophageal motility (IEM). Likewise, high resolution impedance manometry (HRIM) provides information regarding bolus transit. It is not known if HRIM confers a diagnostic advantage over HRPT in the assessment of peristalsis in patients with non-obstructive dysphagia (NOD). Methods: Patients with NOD were evaluated with a 36-pressure and 18-impedance solid-state esophageal probe. Failed, weak and normal peristalses were identified with HRPT, HRIM and CW, independently by two assessors. Abnormal and normal peristalses were compared between the techniques. ROC curve analysis was used to determine area under the curve (AUC), sensitivity and specificity for a diagnosis of IEM using HRIM at cut-offs of 50% (HRIM50%) and 30% (HRIM30%) with CW50% and HRPT50% as references. Results: 81/111 screened patients (F/M = 57/24; mean age 53 years) were evaluated. With HRPT, IEM was seen in 28.0±3.6 % of water swallows, of which failed peristalses were seen in 11.0±2.7 % and weak peristalses in 17.0 ± 2.4 %. Of those ineffective swallows, 8.8±1.8 % were large breaks, 10.5±1.1% were small breaks and 35.4±4.0 % had transition zone defects (TZDs) (mean length 3.1±0.3 cm). Less than a third of subjects had a mean distal contractile integral (DCI)<450 mmHg-s-cm. With HRIM, IEM was seen in 35.1±4.0 %, of which 17.2 ± 3.1 % were failed peristalses and 17.9 ± 2.7% were weak peristalses. The mean distal baseline impedance was 1.3±0.1Ω. TZDs with impaired bolus clearance were seen in 19.4±3.2%. Comparing HRIM vs. HRPT, more failed peristalses (1.8±0.3 vs. 1.2±0.3, P=0.02) were identified, but weak peristalses (1.8±0.3 vs. 1.8±0.3, P=1.0) and normal peristalses (6.1±0.4 vs. 6.0±0.4,P =0.8) were similar. Using ROC curve analysis, the % of AUCs, sensitivities and specificities for HRIM50% (63.2, 48.4 and 78.0 respectively) and HRPT50% (68.2, 48.4 and 88.0 respectively) were both better than CW50% (both P<0.05). Compared with HRPT50%, the % of AUCs, sensitivities and specificities were equally better with HRIM30% (69.8, 76.2 and 63.3 respectively, P=0.007) and HRIM50% (73.3, 66.7 and 80.0 respectively, P=0.002). Conclusion: HRIM is more likely to identify peristaltic defects than HRPT, and therefore is a better test for the assessment of NOD. To diagnose IEM, HRIM30% and HRIM50% were both equally better than HRPT50% and CW50%, and should be the preferred approach. Disclosure - Dr. Rao is supported by a grant from National Institutes of Health NIH grant RO1 DK 57100-05NIHRO-1.