Feasibility of measuring superior mesenteric artery blood flow during cardiac surgery under hypothermic cardiopulmonary bypass using transesophageal echocardiography: An observational study

Trans-Esophageal Echocardiography of the Descending Aorta and Celiac Trunk as an Intraoperative Monitoring for Median Arcuate Ligament Syndrome (MALS) Treatment: Technique Proposal and Two Case Reports

Dunbar syndrome is caused by the compression of the celiac artery by the median arcuate ligament (MAL) and the diaphragmatic crura, presenting with abdominal pain. The treatment is surgical, with the aim of dissecting and separating the diaphragmatic crura from the celiac axis, restoring blood flow in the celiac trunk. We propose the use of transesophageal echocardiography to measure the peak systolic velocity in the celiac trunk and to evaluate, in real time, the efficacy of the surgery during MAL resection. Two clinical cases with practical implications are reported. In one of these, the ultrasound exam was useful in providing an intraoperative confirmation of the outcome of the resection.

Hepatic blood flow in adult Göttingen minipigs and pre-pubertal Danish Landrace x Yorkshire pigs

The liver receives dual blood supply from the hepatic artery and portal vein. The pig is often used as an animal model in positron emission tomography (PET) and pharmacokinetic studies because of the possibility for extensive and direct blood sampling. In this study, we compared measurements of hepatic blood flow in 10 female adult Göttingen minipigs and 10 female pre-pubertal Danish Landrace x Yorkshire (DLY) pigs. Ultrasound transit time flow meter probes were placed around the hepatic artery and portal vein through open surgery, hepatic blood flow measurements were performed, and the liver was weighed. Total hepatic blood flow was on average 363 ± 131 mL blood/min in Göttingen minipigs and 988 ± 180 mL blood/min in DLY pigs (p < 0.001). The mean hepatic blood perfusion was 623 mL blood/min/mL liver tissue and 950 mL blood/min/mL liver tissue (p = 0.005), and the liver weight was 0.58 kg and 1.04 kg, respectively. The mean arterial flow fraction in Göttingen minipigs was 12 ± 7% and lower than in DLY pigs, where it was 24 ± 7% (p = 0.001). Using the gold standard for blood flow measurements, we found that both total hepatic blood flow and blood perfusion were significantly lower in Göttingen minipigs than in DLY pigs. The hepatic blood perfusion and arterial flow fraction in DLY pigs were comparable to normative values from humans. Differences in hepatic blood flow between adult Göttingen minipigs and humans should be considered when performing physiological liver studies in this model.

Usefulness of Transesophageal Echocardiography in the Evaluation of Celiac Trunk and Superior Mesenteric Artery Involvement in Acute Aortic Dissection

Mesenteric ischemia is a serious complication of acute aortic dissection (AAD), and its early diagnosis is vital for prognosis and appropriate treatment indication. Arteries affected by this complication are the celiac trunk and superior mesenteric artery, and their evaluation is usually based on computed tomographic angiography. Transesophageal echocardiography is also a useful technique for diagnosing AAD and is essential in monitoring surgical or endovascular treatment when computed tomographic angiography is not available. However, the usefulness of transesophageal echocardiography for evaluating celiac trunk and superior mesenteric artery involvement and mesenteric ischemia mechanisms in AAD is not well established. Real-time information on mesenteric malperfusion is needed at the bedside, in primary care facilities, and in the operating room to achieve prompt diagnosis and better therapeutic management. The aims of this review are to assess the role of TEE to diagnose celiac trunk and superior mesenteric artery involvement in AAD, determine the mechanisms that can cause flow obstruction in patients with mesenteric ischemia, and analyze possible implications in the treatment of this complication.