HSC Section 6 Nov2016 Green Book

DISCUSSION In a unique cohort of patients who had both off and on therapy testing, we sought to determine if on therapy impedance data can be predicted from the more tradi- tionally recognized and commonly employed off therapy upper endoscopy, manometry, or pH parameters. In this stepwise diagnostic approach, we found that among patients with extraesophageal reflux refractory to PPI

Fig. 2. Individual and group median (IQR) total number of imped- ance events for the three patient subgroups. Impedance events were similar between the groups.

acid reflux (% total time pH < 4) off therapy and total number of impedance events on therapy by patient sub- group. As expected, patients with a normal upper endoscopy and normal pH testing exhibited a significantly ( P < 0.001) lower % total time pH < 4 (3.08% [1.99%– 4.89%]), compared to the patients with a normal upper en- doscopy and abnormal pH testing (10.45% [7.35%– 15.10%]) and those with esophagitis (9.98% [6.70%– 12.66%]) (Fig. 1). However, there was no significant differ- ence among the three groups with respect to median (IQR) total number of impedance events on therapy ( P ¼ 0.61) (27.50 [21.25–47.25];39 [24–51]; 42 [23.25–52.75], respectively) (Fig. 2). Median (IQR) lower esophageal sphincter pressure for the three groups were similar ( P ¼ 0.78) between the three groups (3.0 [1.0–7.0], 5.5 [0.4– 15.5], and 8.0 [1.3–29], respectively). Predictors of Impedance Findings No significant overall relationship was observed between the total number of impedance events and the traditionally recognized physiologic parameters for reflux. Specifically, there was no correlation (r ¼ 0.15, P ¼ 0.2) between the total number of impedance events on therapy and the total % time pH < 4 off therapy (Fig. 3A). Presence or absence of hiatal hernia did not change this relationship (Fig. 3B). However, among patients with endoscopic evidence of esophagitis, there was a weak significant correlation (r ¼ 0.54, P ¼ 0.045) between the on therapy impedance and off therapy pH parameters (Fig. 3C). However, the impedance parame- ters on therapy could not be predicted based on severity of reflux parameters at baseline. Number of impedance events on therapy were similar ( P ¼ 0.99) between patients who had no or mild reflux (% time pH < 4 of less than 10%) compared to those with moderate to severe reflux (% time pH < 4 of more than 10%) (Fig. 4).

Fig. 3. Correlation between % total time pH < 4 off therapy and total number of impedance events on therapy for Overall (A), stratified by hi- atal hernia (B), and stratified by endoscopic presence of esophagitis (C). HH þ ¼ hiatal hernia present; HH ¼ no hiatal hernia; Esop ¼ no esophagitis; Esop þ ¼ esophagitis. [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com.]

Laryngoscope 123: October 2013

Kavitt et al.: The Role of Impedance Monitoring in Extraesophageal Symptoms

142