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Use of computed tomographic and digital subtraction angiography to determine optimal duplex ultrasound criteria for predicting superior mesenteric artery in-stent restenosis

Over the past two decades, the primary treatment paradigm for chronic mesenteric ischemia (CMI), most frequently caused by superior mesenteric artery (SMA) occlusive disease, has shifted from open surgical towards endovascular therapies. However, endovascular therapies are associated with up to 50% lower primary patency rates largely due to in-stent restenosis (ISR).1 The 2020 Society for Vascular Surgery Clinical Practice Guidelines recommend post-stenting surveillance using duplex ultrasound (DUS).2 However, there are no consensus duplex criteria for SMA ISR. Previous studies have demonstrated that DUS velocity criteria for stenosis of the native, or unstented, SMA overestimate SMA ISR, potentially resulting in unnecessary diagnostic testing.3 Despite the efforts of prior studies with modest sample sizes,4–7 there are no consensus DUS velocity criteria for predicting SMA ISR. Furthermore, most of these studies compared DUS to digital subtraction angiography (DSA) studies, the traditional gold standard for duplex velocity validation. However, in real-world practice, computed tomography angiography (CTA) is frequently utilized to assess recurrent restenosis.2,8 Thus, the goal of this study was to identify optimal DUS velocity criteria for SMA ISR using both DSA and CTA. We performed a retrospective cohort study of patients who underwent SMA stenting in the Division of Vascular Surgery at Northwestern Memorial Hospital (Chicago, IL) between 2014 and 2020. The study protocol was approved by the Northwestern University Institutional Review Board. Postoperative CTA or DSA performed within 3 months of DUS were selected for inclusion as a ‘paired’ study. All DUS were performed by a Registered Vascular Technologist credentialed by the American Registry for Diagnostic Medical Sonography in a vascular lab accredited by the Intersocietal Accreditation Commission. Angiographic SMA ISR was quantified by two independent reviewers using electronic calipers from CTA and DSA studies. In the case of CTA studies, the minimum diameter from axial, sagittal, and coronal planes was used (online Supplemental Figure 1). A third independent reviewer was used to adjudicate disagreements between the other reviewers. Percentage stenosis was averaged across all reviewers. Maximum peak systolic velocity (PSV) and end diastolic velocity (EDV) in the stented SMA were recorded from each paired DUS study. Receiver operator characteristic (ROC) curves were constructed to determine optimal PSV and EDV thresholds for detecting ⩾ 70% angiographic ISR using the closest top-left method. During the study period, 116 patients underwent SMA stenting. Among these, a total of 48 paired DUS and angiographic studies in 25 patients (mean age 68 years, 72% female) were eligible for analysis. Eleven patients had one paired study and 14 patients had two or more paired studies. DSA was used in 22 of the paired studies (46%) and CTA in 26 of the paired studies (54%). There was ⩾ 70% angiographic ISR in 12 paired studies (25%) from nine patients. PSV (556 vs 331 cm/s, p < 0.001) and EDV (155 vs 76 cm/s, p < 0.001) were both significantly higher in paired studies with ⩾ 70% ISR than those with < 70% ISR. Using ROC analysis, the optimal DUS criteria for predicting ⩾ 70% SMA ISR were PSV ⩾ 457 cm/s (sensitivity = 100%, specificity = 97.2%) (Figure 1A) and EDV ⩾ 81.6 cm/s (sensitivity = 91.7%, specificity = 74.3%) Use of computed tomographic and digital subtraction angiography to determine optimal duplex ultrasound criteria for predicting superior mesenteric artery in-stent restenosis