Microbubble contrast-enhanced ultrasound in the vascular evaluation after pancreas transplantation: a single-center experience

Background: Arterial and venous thrombosis are feared complications of pancreas transplantation (PTx). Microbubble contrast-enhanced ultrasound (CEUS) is a non-invasive imaging technique that can augment diagnostic capabilities of transplant organ perfusion. Purpose: To document the state to which CEUS can improve the vascular evaluation of PTx compared to conventional Doppler ultrasound (US) directly after surgery. Material and Methods: A total of 129 consecutive PTx in 128 adult patients were eligible for inclusion. The duodenal segment of the graft was anastomosed to the native duodenum. Within 12 h postoperatively, graft- circulation was monitored by Doppler US in 116 PTx performed in 116 patients (69 men, 47 women; mean age 41 years). CEUS was performed with a sulfur hexafluoride-containing contrast agent (SonoVue) intravenously if the examiner was not able to confirm normal graft circulation. Image quality was documented by two independent observers on a 4-point scale: 1 excellent; 2 minor diagnostic limitations; 3 major diagnostic limitations; and 4 non-diagnostic. Results: In the early postoperative phase, 79 (68%) of 116 PTx were examined with Doppler US only. Of these, 52 were of excellent quality (grade 1), 22 of good quality (grade 2), and five were of grade 3 or 4 quality. Thirty-seven (32%) examinations were supplemented by CEUS. CEUS significantly improved examination quality compared to Doppler US alone (median visualization score 1.5 vs. 2.5, respectively; P < 0.0001). Conclusion: CEUS can significantly improve vascular evaluation of PTx compared to Doppler US alone in the early postoperative phase

Early detection of complications in pancreas transplants by microdialysis catheters, an observational feasibility study

Background Despite advances in immunosuppression and surgical technique, pancreas transplantation is encumbered with a high rate of complication and graft losses. Particularly, venous graft thrombi occur relatively frequently and are rarely detected before the transplant is irreversibly damaged. Methods To detect complications early, when the grafts are potentially salvageable, we placed microdialysis catheters anteriorly and posteriorly to the graft in a cohort of 34 consecutive patients. Glucose, lactate, pyruvate, and glycerol were measured at the bedside every 1–2 hours. Results Nine patients with graft venous thrombosis had significant lactate and lactate–to-pyruvate-ratio increases without concomitant rise in blood glucose or clinical symptoms. The median lactate in these patients was significantly higher in both catheters compared to non-events (n = 15). Out of the nine thrombi, four grafts underwent successful angiographic extraction, one did not require intervention and four grafts were irreversibly damaged and explanted. Four patients with enteric anastomosis leakages had significantly higher glycerol measurements compared to non-events. As with the venous thrombi, lactate and lactate-to-pyruvate ratio were also increased in six patients with graft surrounding hematomas. Conclusions Bedside monitoring with microdialysis catheters is a promising surveillance modality of pancreatic grafts, but differentiating between the various pathologies proves challenging