Evaluation of Imaging Modalities for Superior Mesenteric Artery Stenosis: A Single Centre Study

To evaluate intra-arterial pressure measurement (IAPM) in relation to pre- and intra-operative diagnostic methods for assessing superior mesenteric artery (SMA) stenosis in patients with a diagnosis of chronic mesenteric ischaemia.

This secondary analysis compares computed tomography angiography (CTA), duplex ultrasound (DUS), digital subtraction angiography (DSA), and IAPM, using IAPM as the reference standard. Thirty patients were enrolled in the Copenhagen Mesenteric Stent Study (COMESS), a randomised clinical trial evaluating covered vs. uncovered stents for treating SMA stenosis (COMESS trial, ClinicalTrials.org identifier NCT05244629). All included patients were thoroughly examined upon referral to exclude other relevant causes of chronic abdominal pain. All patients had a clinical diagnosis of chronic mesenteric ischaemia and >50% SMA stenosis on CTA. All underwent DUS, DSA, and IAPM. DUS assessed the peak systolic velocity (centimetres per second) across the SMA. During endovascular intervention, DSA was performed in the anteroposterior and lateral projections. A dedicated pressure wire measured the trans-stenotic mean arterial pressure gradient between the SMA and aorta.

There was a statistically significant positive correlation between DUS and IAPM (r = 0.698, p = 0.003, 95% confidence interval 253-373), indicating a moderately strong association, with a peak systolic velocity of 372 cm/sec on DUS corresponding to a mean arterial pressure between 15 and 20 mmHg. DSA showed a non-significant correlation with IAPM (r = 0.376, p = 0.11, standard deviation 0.128), with 59% stenosis corresponding to a 10 mmHg gradient. There was no significant correlation between CTA and IAPM (r = 0.143, p = 0.50, 95% confidence interval -43 - 60).

DUS shows the best association with IAPM when differentiating a significant SMA stenosis. In contrast, CTA demonstrated no significant correlation with IAPM; however, CTA is of importance for differential diagnosis. Therefore, when SMA stenosis is identified on CTA, further confirmation with DUS is recommended, for moderate to less than pre-occlusive or occlusive SMA stenosis, to determine the need for DSA and potential endovascular treatment.