Introduction 1 3 4 9 10 11 13 14 Methods Patients with unexplained chronic abdominal symptoms who were referred for suspected CGI were included in this study. More-common causes of chronic abdominal symptoms had been excluded previously by appropriate diagnostic evaluation. All patients had imaging of the splanchnic arteries [intra-arterial digital substraction multiplane abdominal angiography (DSA) and duplex ultrasound scanning] and GET. Along with this standard diagnostic work up, patients had twenty-four hour (24 h) tonometry testing, directly following GET. Gastric exercise tonometry (GET) 15 2 2 8 15 Twenty-four hour tonometry testing ® 2 t ® 1 2 Table 1 Composition characteristics of the various standard meals Meal Composition kcal/g Breakfast  Fat (16%), proteins (22%), carbohydrates (62%) 1.7 Dinner Fat (16%), proteins (47%), carbohydrates (37%) 2.2 Bread meal Fat (10%), proteins (19%), carbohydrates (71%) 1.8 Compound solution Fat (35%), proteins (16%), carbohydrates (49%) 1.5 Percentages of delivered energy (En%); kcal = kilocalories; g = gram. Diagnosis and treatment The results of all diagnostic procedures were discussed in a multidisciplinary team. In this team a gastroenterologist, a vascular surgeon, and an interventional radiologist discussed the symptoms, medical history, physical examination, and all diagnostic evaluations, with the exception of the results on 24-h tonometry. The latter therefore did not influence the consensus diagnosis. The multidisciplinary team decided for every patient: (1) no splanchnic stenosis, (2) splanchnic stenosis and no ischemia or (3) splanchnic stenosis and ischemia (i.e. chronic gastrointestinal ischemia, CGI). The gold standard for the diagnosis of chronic gastrointestinal ischemia was a positive outcome after successful revascularization at (long-term) follow-up. The outcome of GET, and consensus diagnosis of the multidisciplinary team were compared to the results of the 24-h tonometry testing. Definition of a positive (abnormal) 24 h tonometry 9 2 Statistics t χ 2 Results Patient characteristics In a period of three years (2002–2005), in 37 patients referred for suspected of CGI, 24-h tonometry along with the standard work-up was performed. Of these, 33 (89%) patients had complete work-up and were included in this study. Mean age was 54 (22–82) years, with eight males and 25 females. Significant splanchnic stenosis were found in 23/33 (69%) patients. A significant single vessel splanchnic stenosis was found in 14/33 (42%) patients [13 celiac artery (CA) and one superior mesenteric artery (SMA)]. A significant stenosis of two splanchnic arteries was found in 9/33 (27%) patients (all CA and SMA stenosis). 1 Gastric exercise tonometry 8 Consensus diagnosis of the multidisciplinary team and results after treatment According to the team the diagnosis of no stenosis (and no ischemia), stenosis but no ischemia, and stenosis with ischemia (CGI) was diagnosed in, respectively, 12 (36%), four (12%) and 17 (52%) patients. 2 Table 2 Patient characteristics, results of diagnostic tests and conclusion Nr Age Sex Stenosis PP pain PE pain GET results Consensus diagnosis Treatment Outcome complaints Final conclusion 24-h tono results 1 61 F None + − 0,5 No stenosis, no ischemia –  No stenosis, no ischemia Normal 2 36 M CA + − 0,4 No ischemia –  No ischemia Normal 3 55 F CA + − a CGI Surgery Free CGI Abnormal 4 76 M None − − 0,6 No stenosis, no ischemia –  No stenosis, no ischemia Normal 5 47 M None − + b No stenosis, no ischemia –  No stenosis, no ischemia Normal 6 42 F CA + SMA − − 1,5 CGI Surgery Free CGI Abnormal 7 65 F CA + SMA − − 2,0 CGI Conservative  CGI Abnormal 8 77 F CA + SMA + − 2,2 CGI Surgery Died post-op. CGI Abnormal 9 72 F SMA + + 1,8 CGI Stent Free CGI Abnormal 10 41 M None + − c No stenosis, no ischemia –  No stenosis, no ischemia Normal 11 72 F CA + − 1,4 CGI Stent Partial relieve CGI Abnormal 12 67 F CA − − c No stenosis, no ischemia –  No ischemia Normal 13 40 F CA − + c CGI Surgery Unchanged No ischemia Normal 14 82 M CA + SMA + + 1,0 CGI Conservative  CGI Normal 15 54 F CA + + 0,9 CGI Conservative  CGI Normal 16 26 M CA + + 1,0 CGI Surgery Free CGI Abnormal 17 58 M None + + c No stenosis, no ischemia –  No stenosis, no ischemia Normal 18 22 F CA + − 0,7 No ischemia –  No ischemia Normal 19 42 F None + − d No stenosis, no ischemia –  No stenosis, no ischemia Normal 20 48 F CA + − 1,7 CGI Surgery Free CGI Normal 21 51 F CA + − 0,7 No ischemia –  No ischemia Normal 22 43 F CA + SMA + + e CGI Surgery Free CGI Abnormal 23 54 F CA + SMA − − 1,5 CGI Surgery Free CGI Normal 24 76 F CA + SMA + − f CGI Stent Free CGI Abnormal 25 53 M None + − c No stenosis, no ischemia –  No stenosis, no ischemia Normal 26 53 F CA + + 1,1 CGI Stent Free CGI Abnormal 27 50 F CA − − 1,3 CGI Surgery Free CGI Abnormal 28 61 F CA + SMA + + 1,7 CGI Stent Free CGI Abnormal 29 63 F None + − 0,8 No stenosis, no ischemia –  No stenosis, no ischemia Normal 30 24 F CA + + 1,3 CGI Surgery Free CGI Abnormal 31 74 F CA + SMA − − 0,8 No ischemia –  No ischemia Normal 32 41 F None + − d No stenosis, no ischemia –  No stenosis, no ischemia Normal 33 63 F None + − 0,0 No stenosis, no ischemia –  No stenosis, no ischemia Abnormal PP = postprandial, PE = post-exercise, M = male, F = female; CA = celiac artery, SMA = superior mesenteric artery; GET = gastric exercise tonometry, result presented as gradient (in kPa); 24-h tono = twenty-four hour tonometry; CGI = chronic gastrointestinal ischemia. a b c d 2 e f Twenty-four hour tonometry 1 Fig. 1  A B A B 2 2  2 2 3 4 Table 3 Results of 24-h tonometry in ischemic and non-ischemic patients  CGI pts. Non-ischemic pts. Peak Δ-peak 2 Peak Δ-peak 2 Stomach B 10.6 (3.9) 4.0 (3.4) – 8.5 (2.7) 2.6 (2.0) – D 9.9 (1.9) 3.7 (1.5) – 8.5 (2.3) 3.3 (2.5) – CS 10.4 (3.0) 3.3 (2.2) – 8.1 (2.6) 1.8 (1.2) – Fasting – – a – – 6.8 (0.7)     Day – – 6.9 (1.1) – – 6.5 (0.7)     Night – – 8.2 (1.8) – – 6.9 (0.8) Jejunum B b 3.2 (1.5) – 8.8 (1.4) 2.1 (0.8) – D c 3.7 (2.0) – 9.0 (1.7) 2.2 (0.7) – CS 10.6 (2.2) 2.5 (1.6) – 9.0 (1.9) 1.5 (1.0) – Fasting – – d – – 7.4 (0.7)     Day – – 8.8 (1.3) – – 7.5 (0.9)     Night – – 8.9 (1.9) – – 7.5 (0.8) 2 a P b P c P d P Table 4 Results of different tests compared to final diagnosis Patients Final diagnosis GET 24-h tonometry Combination GET––24-h tonometry CGI  17 14 (82%) 13 (76%) 17 (100%) No ischemia 16 11 (69%) 15 (94%) 16 (100%) Data presented as number of patients with positive predictive value (PPV) and negative predictive value (NPV); GET = gastric exercise tonometry; CGI = chronic gastrointestinal ischemia; GET = gastric exercise tonometry Using the previously defined criteria, 13/17 patients with CGI and 15/16 patients without ischemia were correctly identified with 24-h tonometry. The calculated test properties show a sensitivity of 76% and a specificity of 94%, a positive predictive value (PPV) of 76% and a negative predictive value (NPV) of 94% for detection of ischemia by 24-h tonometry alone. Combining the results of GET and 24-h tonometry, 17/17 patients with CGI and 16/16 patients without ischemia could be correctly identified (sensitivity of 100% and specificity of 100%). Comparing patients with single- and multi-vessel ischemia, or patients with or without postprandial and/or exercise-related complaints, no significant differences in diagnostic accuracy were found. Discussion The results of this retrospective study indicate that 24-h gastrojejunal tonometry is feasible and may be clinically useful in diagnosing chronic gastrointestinal ischemia. The measurements were easy to perform, generally well tolerated and no complications occurred. 2 P 14 15 2 2 16 In conclusion, this retrospective study shows that 24-h tonometry is feasible, safe, and has a very promising diagnostic accuracy for the detection of gastrointestinal ischemia. Using high-dose PPI acid suppression and standard meals, and previously established normal values, 24-h tonometry identifies gastrointestinal ischemia with an acceptable accuracy. The definitive role of 24-h tonometry in the diagnosis of chronic gastrointestinal ischemia has to be established in (future) prospective studies.