The Western Thoracic Surgical Association

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Pre- And Post-lung Transplant Foregut Function
Takahiro Masuda, Sumeet K Mittal, Balazs Kovacs, *Michael A Smith, Rajat Walia, *Jasmine Huang, *Ross M Bremner
Norton Thoracic Institute, Phoenix, AZ

BACKGROUND: Esophageal dysmotility and gastroesophageal reflux disease are common in patients with advanced lung disease. Significant differences in the prevalence of pathological reflux between patients with obstructive lung disease (OLD) and restrictive lung disease (RLD) has been reported, as these groups have contrasting respiratory mechanics. However, changes in esophageal motility and gastroesophageal reflux in patients undergoing lung transplantation (LTx) have not been reported. In this study, we evaluated the effects of LTx on foregut function in LTx recipients.
METHODS: All patients undergoing LTx at our institution are entered into a prospectively maintained database. We queried this database to identify patients who underwent pre- and post-LTx foregut function tests (ie, high-resolution manometry [HRM], 24-hour pH monitoring, upper gastrointestinal endoscopy, and gastric emptying studies). Underlying pulmonary disease was classified using the United Network for Organ Sharing criteria. We compared patients diagnosed with OLD with patients diagnosed with RLD.
RESULTS: In total, 204 patients underwent LTx at our institution between January 2014 and December 2016. Of these, 142 underwent complete pre- and post-LTx foregut function testing. Patients with previous LTx (n=8), prior foregut intervention (n=7), and poor-quality study (n=15) were excluded. The mean age of the remaining 112 patients was 62.0 years; mean body mass index was 25.8 kg/m2. 62 patients (55.4%) were men. 51 patients (45.5%) were diagnosed with OLD, 56 (50.0%) were diagnosed with RLD, 3 (2.7%) had pulmonary hypertension, and 2 (1.8%) had cystic fibrosis. Postoperative HRM was done at an average of 4.9 months post-LTx. 57 patients (50.9%) had a change in manometric diagnosis from pre-LTx to post-LTx, trending toward improved peristaltic vigor. 17/39 patients (43.6%) with abnormal pre-LTx pH scores had normal post-LTx pH scores; however, 20/73 patients (27.4%) with normal pre-LTx pH scores had abnormal pH scores post-LTx. Pre-LTx, the RLD group had a higher prevalence of pathological reflux and absent peristalsis compared with the OLD group (42.9% vs 19.6%, p=0.010; 8.9% vs 0%, p=0.036, respectively; Table 1); however, the prevalence of hiatal hernia, competency of lower esophageal sphincter (LES) function, and delayed gastric emptying were similar between groups. Importantly, the pre-LTx thoracoabdominal pressure gradient (TAPG) was greater in the RLD group than in the OLD group (23.4 vs 14.7 mmHg, p<0.001), which may illuminate the mechanism of increased reflux in patients with RLD. No differences were seen in the post-LTx prevalence of pathological reflux, existence of hiatal hernia, LES function, TAPG, and incidence of delayed gastric emptying between groups (Table 1).
CONCLUSIONS: HRM findings and pH scores are significantly different in patients with OLD and RLD, but these differences are diminished after LTx, suggesting that LTx can ameliorate the inhibited pulmonary aerodynamics that confound esophageal function. This large study justifies perioperative foregut function testing.

OLD (n=51)RLD (n=56)OLD (n=51)RLD (n=56)
Age, years a63.0 (57.0-68.0)66.0 (61.0-68.5)63.0 (57.0-68.0) 66.0 (62.0-69.5)
Sex (M:F)25:2637:1925:2637:19
BMI, kg/m2 a24.2 (20.8-27.3)27.2 (24.0-30.5) 24.7 (22.3-28.5)25.2 (23.4-27.7) ||
DeMeester score a4.7 (1.8-11.1)12.1 (3.7-25.7) 9.8 (2.4-24.5) §12.4 (4.6-29.0)
Abnormal DeMeester score b10 (19.6%)24 (42.9%) 16 (31.4%)22 (39.3%)
% time pH<4, % a1.0 (0.3-2.3)3.1 (0.8-6.3) 2.2 (0.4-6.6) ||2.9 (1.0-8.1)
Manometric hiatal hernia b16 (31.4%)14 (25.0%)9 (17.6%) § 8 (14.3%)
LES function aLESP, mmHg31.2 (20.2-38.9)32.4 (17.9-37.3)32.3 (21.5-52.2) § 32.0 (20.6-39.8)
LESPI, mmHg·s·cm196.5 (89.5-490.2)236.3 (112.5-338.9)262.5 (130.4-699.2) §256.0 (93.2-507.2)
OL, cm2.7 (2.3-3.1)2.8 (2.4-3.3)2.7 (2.2-3.3)2.8 (2.5-3.2)
AL, cm2.1 (1.2-2.5)2.2 (1.8-2.7)2.3 (1.8-2.7) §2.4 (2.0-2.8)
HRM diagnosis bNormal26 (51.0%)22 (39.3%)24 (47.1%)34 (60.7%) §
IEM14 (27.5%)21 (37.5%)8 (15.7%)11 (19.6%) §
Fragmented peristalsis1 (2.0%)3 (5.4%)2 (3.9%)1 (1.8%)
DES1 (2.0%)000
Jackhammer esophagus3 (5.9%)06 (11.8%)1 (1.8%) *
Absent contractility05 (8.9%) *02 (3.6%)
EGJOO5 (9.8%)4 (7.1%)7 (13.7%)7 (12.5%)
Achalasia1 (2.0%)1 (1.8%) 4 (7.8%)0 *
Mean DCI, mmHg·s·cm a1321.6 (447.4-3305.0)739.2 (201.7-1492.6) 2347.0 (772.5-4089.3) ||1048.3 (50.3.5-2519.7) *
TAPG, mmHg a14.7 (11.3-20.5)23.4 (15.5-32.0) 17.8 (13.9-24.2) §18.7 (10.7-25.3) §
Gastric emptying studyn=43n=43n=47n=48
Delayed gastric emptying b1 (2.3%)1 (2.3%)10 (21.3%) ||10 (20.8%) ||
a Values expressed as median (IQR)│ b Values expressed as number (%). * p<0.05, † p<0.01, ‡ p<0.001 compared between OLD and RLD either before or after transplantation. § p<0.05, || p<0.01, ¶ p<0.001 compared between pre- and post-LTx in each individual. LTx, lung transplantation; OLD, obstructive lung disease; RLD, restrictive lung disease; BMI, body mass index; LES, lower esophageal sphincter; LESP, resting LES pressure; LESPI, LES pressure integral; OL, overall LES length; AL, abdominal LES length; IEM, ineffective esophageal motility; DES, diffuse esophageal spasm; EGJOO, esophagogastric junction outflow obstruction; DCI, distal contractile integral; TAPG, thoraco-abdominal pressure gradient.

Table 1. Characteristics of patients with obstructive lung disease versus restrictive lung disease

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