Johannes A. Otte

Clinical significance of splanchnic artery stenosis.

The clinical relevance of splanchnic artery stenosis is often unclear. Gastric exercise tonometry enables the identification of patients with actual gastrointestinal ischaemia. A large group of patients with splanchnic artery stenosis was studied using standard investigations, including tonometry.

Clinical Impact of Gastric Exercise Tonometry on Diagnosis and Management of Chronic Gastrointestinal Ischemia

BACKGROUND & AIMS Chronic gastrointestinal ischemia or chronic splanchnic syndrome is a difficult diagnosis. The use of a physiologic test, combined with clinical and anatomic data, should improve diagnostic accuracy. This study evaluates the diagnostic accuracy and clinical impact of gastric tonometry during exercise (GET) in a patient cohort suspected of chronic splanchnic syndrome. METHODS From 1997 to 2000, 102 patients with chronic abdominal pain were analyzed. The workup included GET and selective biplane angiography. The diagnosis of gastrointestinal ischemia was based on consensus in a multidisciplinary working group and sustained on follow-up. RESULTS Gastrointestinal ischemia was diagnosed in 38 patients. In 33 patients chronic splanchnic syndrome was found, with single vessel involvement in 20 (17 celiac artery, 3 mesenteric superior) and multivessel disease in 13. In 5 patients nonocclusive ischemia was found. By using receiver operator curve analysis, the difference between gastric and arterial partial pressure of carbon dioxide (PCO2 gradient) proved to be the best GET parameter. The criteria for diagnosing ischemia in GET were Pco2 gradient > 0.8 kPa and increase gastric PCO2, with base excess decrease <8 mmol/L during exercise. GET had 78% sensitivity and 92% specificity. Twenty-five patients underwent vascular treatment (19 operative, 6 stent/percutaneous transluminal angioplasty). After 4 years of follow-up 83% of patients were alive and free of symptoms. CONCLUSIONS GET is an accurate diagnostic tool to show gastrointestinal ischemia. Including GET into clinical decision making enabled selecting patients with ischemia, who benefited from vascular and medical treatment. These benefits were sustained during 4-year follow-up. GET should be considered in the workup of patients with a suspected diagnosis, of gastrointestinal ischemia.

What is the best diagnostic approach for chronic gastrointestinal ischemia

BACKGROUND: Chronic gastrointestinal ischemia is still a difficult diagnosis to establish. The diagnosis depends on a high degree of clinical suspicion as well as selective angiography. Duplex sonography may serve as a screening tool, providing information on splanchnic vessel patency and flow patterns. GET is a minimally invasive test that can be used for diagnosis in patients with chronic gastrointestinal ischemia, and can differentiate between symptomatic and asymptomatic splanchnic artery stenosis. In the present study, we compared four different diagnostic approaches.METHODS: Between 1997 and 2000, 84 patients were evaluated for suspected chronic gastrointestinal ischemia. All underwent splanchnic arterial angiography, duplex sonography, and GET. For the presence or absence of stenosis, angiography was used as the gold standard. For diagnosing ischemia, we relied on a panel decision. The diagnostic approaches studied were: (a) angiography, only in patients with classic abdominal angina; (b) screening with duplex sonography, angiography if sonography abnormal or unreliable; (c) screening with gastric tonometry and angiography if tonometry not normal; (d) both gastric tonometry exercise and duplex sonography, angiography if one of both screening tests not normal.RESULTS: In 28 patients, chronic gastrointestinal ischemia was diagnosed. Using clinical suspicion only, 16 patients (57%) would have been missed. Screening by duplex sonography or gastric tonometry only would have missed 4 or 6 patients, respectively. Screening with combined gastric tonometry and duplex sonography would not have missed patients with symptomatic ischemia, while 21% of angiographies would have been avoided.CONCLUSION: Screening by combined GET and duplex sonography has excellent diagnostic accuracy. Currently, this approach represents the best diagnostic workup strategy in patients with suspected chronic gastrointestinal ischemia.

Jejunal tonometry for the diagnosis of gastrointestinal ischemia. Feasibility, normal values and comparison of jejunal with gastric tonometry exercise testing.

Background and aim In most patients with chronic splanchnic syndrome the celiac artery is involved, enabling the use of gastric exercise tonometry as a diagnostic function test. In this study, we investigated the feasibility of combining gastric and jejunal exercise tonometry and determined the normal values. We investigated the potential diagnostic value of combining gastric with jejunal exercise tonometry. Materials and method Between 1998 and 2000, combined gastric and jejunal exercise tonometry tests were performed in a healthy volunteer and in patients suspected of chronic gastrointestinal ischemia. Using automated air tonometry, gastric (PgCO2) and jejunal PCO2 (PjCO2) were measured before, during and after 10-min of exercise. Luminal–arterial PCO2 gradients (ΔgPCO2 respectively ΔjPCO2) were calculated. In the patient cohort, final diagnosis of chronic ischemia was made by our institutional multidisciplinary working group on gastrointestinal ischemia. Results Jejunal tonometry was possible in 25 of 27 participants. The healthy volunteer was tested twice, yielding a total of 26 combined tests. Mean normal basal PjCO2 was 0.9 kPa higher than PgCO2. The calculated upper threshold (mean+2SD) of normal ΔjPCO2 was 1.4 kPa. In five of eight patients with chronic gastrointestinal ischemia gastric exercise tonometry was abnormal, in one, both gastric and jejunal tonometry were abnormal, in two only jejunal exercise tonometry was abnormal. Conclusion Combined gastric and jejunal exercise tonometry is a feasible procedure that is relatively easy to perform. On the basis of this pilot study, jejunal tonometry seems to have a small additional value in the diagnosis of chronic gastrointestinal ischemia.

Triggering for submaximal exercise level in gastric exercise tonometry: serial lactate, heart rate, or respiratory quotient?

Gastric exercise tonometry is a functional diagnostic test in chronic gastrointestinal ischemia. As maximal exercise can cause false-positive tests, exercise buildup should be controlled to remain submaximal. We evaluated three parameters for monitoring and adjusting exercise levels (heart rate [HR], respiratory quotient [RQ], and serial lactate measurements) in 178 tests in both healthy volunteers and patients suspected of gastrointestinal ischemia. Exercise levels above submaximal occurred in 20% of HR-, 2% of RQ-, and 5% of lactate-monitored tests (P<0.05 for HR vs. RQ and lactate). Low levels were seen in 5% of HR-, 10% of RQ-, and 41% of lactate-monitored tests (P<0.01 for lactate vs. HR and RQ). High levels resulted in 43% false-positive tonometry results compared to 19% of all tests (P<0.001); low levels did not result in more false negatives (5% vs. 6%). Although RQ monitoring yielded the greatest proportion of optimal exercise tests, serial lactate monitoring is our method of choice, combining optimal diagnostic accuracy, low cost, and simplicity.

Gastrointestinal Pco2 tonometry in 1998

Gastrointestinal luminal tonometry is a minimally invasive monitoring technique for critically ill patients. It is not widely accepted yet, possibly because of uncertainties with respect to physiologic background, methodology, and clinical usefulness. This review discusses recent developments, including automated air tonometry, that might render tonometry easier to apply by replacing the laborious and error-prone manual saline technique, the value of the blood-intragastric PCO2 gap versus the intramucosal pH, the need for gastric acid suppression during tonometry in the stomach, the sources of error for fluid PCO2 tonometry, and the luminal PCO2 in parts of the gastrointestinal tract other than the stomach. Finally, new clinical investigations are reviewed.