Quantitative change of perfusion in gastric tube reconstruction by sidestream dark field microscopy (SDF) after esophagectomy, a prospective in-vivo cohort study

Analysis of surgical outcomes and risk factors for anastomotic leakage following trans-hiatal resection of esophagogastric junction cancer

BACKGROUND

The trans-hiatal lower esophagectomy is considered less invasive than the trans-thoracic esophagectomy for resection of esophagogastric junction (EGJ) cancer. However, the optimal procedure remains controversial and should be determined while considering both oncological and safety aspects.

METHODS

This retrospective study comprised 124 patients that underwent curative resection for EGJ cancer. The study analysis included 93 patients with tumor centers located within 2 cm of the EGJ. Clinicopathological findings and surgical outcomes were compared between patients treated using trans-hiatal and trans-thoracic approaches.

RESULTS

Sixty-three patients underwent lower esophagectomy using the trans-hiatal approach (TH-G). The remaining 30 patients underwent esophagectomy using the trans-thoracic approach (TT-E). The TH-G group were older, had a lower prevalence of lymphatic spread, shorter length of esophageal invasion, and shorter operative duration compared to the TT-E group. Although no significant differences in the frequency of postoperative complications, a higher proportion of patients in the TH-G group developed anastomotic leakage (16% vs. 7%, p = 0.33). Univariate and multivariate analyses demonstrated that cardiac comorbidity was an independent risk factor for anastomotic leakage (odds ratio, 5.24; 95% CI, 1.06-25.9; P < 0.05) in TH-G group. Further examination revealed that preoperative cardiothoracic ratio (CTR) with 50% or greater could be surrogate marker as risk factor for anastomotic leakage in TH-G group (35% vs. 7.5%, p < 0.05).

CONCLUSIONS

The trans-hiatal approach can be used for resection of EGJ cancer. However, special attention should be paid to the prevention of anastomotic leakage in patients with cardiac comorbidities or a large preoperative CTR.

Real-time semi-quantitative assessment of anastomotic blood perfusion in mini‑invasive rectal resections by Sidestream Dark Field (SDF) imaging technology: a prospective in vivo pilot study

PURPOSE

Anastomotic leakage (AL) is one of the severe complications after rectal surgery, and anastomotic ischemia is one of the main factors. This prospective in vivo pilot study aimed to evaluate the effectiveness of Sidestream Dark Field (SDF) imaging in quantitative assessment of anastomotic microcirculation and to analyze its correlation with AL.

METHODS

Thirty-three patients with rectal cancer who underwent laparoscopic low anterior resection from 2019 to 2020 were enrolled. Microcirculation was measured by SDF imaging at the descending colon, the mesocolon transection line (MTL), and 1 cm and 2 cm distal to the MTL. Anastomotic microcirculation was measured at the stapler anvil edge before anastomosis. Quantitative perfusion-related parameters were as follows: microcirculation flow index (MFI), perfused vessel density (PVD), proportion of perfused vessels (PPV), and total vessel density (TVD).

RESULTS

All patients obtained stable microcirculation images. Functional microcirculation parameters (MFI, PPV, PVD) decreased successively from the descending colon, the colon at MTL, and 1 cm and 2 cm distal to the MTL (all P < 0.01). Extremely poor microcirculation was found at the intestinal segment 2 cm distal to the MTL. Micro-perfusion was significantly lower at the colonic limb of the anastomosis compared with the descending colon (all P < 0.001). Anastomotic leakage occurred in 3 patients (9.1%) whose anastomotic microcirculation was significantly lower than those without AL (all P < 0.01). Blood perfusion at the colonic limb of the anastomosis was significantly higher in patients with left colic artery preservation than in controls.

CONCLUSION

SDF imaging is a promising technique for evaluating anastomotic microcirculation and has potential clinical significance for risk stratification of AL.

Near-infrared fluorescence imaging with indocyanine green to assess the blood supply of the reconstructed gastric conduit to reduce anastomotic leakage after esophagectomy: a literature review

The blood supply of the right gastroepiploic artery after esophagectomy with gastric tube reconstruction is essential for avoiding anastomotic leakage. Near-infrared fluorescence (NIRF) imaging with indocyanine green is widely used to assess the blood supply because it can visualize it in real-time during navigation surgery. However, there is no established protocol for this modality. One reason for this lack of protocol is that NIRF provides subjective information. This study aimed to evaluate NIRF quantification. We conducted a literature review of risk factors for anastomotic leakage after esophagectomy, NIRF procedures, NIRF quantification, and new methods to compensate for NIRF limitations. Major methods for the quantification of NIRF include measuring the blood flow speed, visualization time, and fluorescence intensity. The cutoff value for the blood flow speed is 2.07 cm/s, and that for the visualization time is 30-90 s. Although the time-intensity curve provided patterns of change in the blood flow, it did not show an association with anastomotic leakage. However, to compensate for the limitations of NIRF, new devices have been reported that can assess tissue oxygenation perfusion, organ hemoglobin concentration, and microcirculation.

Quantitative Fluorescence Imaging of Perfusion—An Algorithm to Predict Anastomotic Leakage

This study tests fluorescence imaging-derived quantitative parameters for perfusion evaluation of the gastric tube during surgery and correlates these parameters with patient outcomes in terms of anastomotic leakage. Poor fundus perfusion is seen as a major factor for the development of anastomotic leakage and strictures. Fluorescence perfusion imaging may reduce the incidence of complications. Parameters for the quantification of the fluorescence signal are still lacking. Quantitative parameters in terms of maximal intensity, mean slope and influx timepoint were tested for significant differences between four perfusion areas of the gastric tube in 22 patients with a repeated ANOVA test. These parameters were compared with patient outcomes. Maximal intensity, mean slope and influx timepoint were significantly different between the base of the gastric tube and the fundus (p < 0.0001). Patients who developed anastomotic leakage showed a mean slope of almost 0 in Location 4. The distance of the demarcation of ICG to the fundus was significantly higher in the three patients who developed anastomotic leakage (p < 0.0001). This study presents quantitative intra-operative perfusion imaging with fluorescence. Quantification of the fluorescence signal allows for early risk stratification of necrosis.

Effect of Surgical Technique on the Microstructure and Microcirculation of the Small Intestine Stump during Delayed Anastomosis: Multimodal OCT Data

The aim of the study was to use multimodal optical coherence tomography (MM OCT) to evaluate microstructure and microcirculation in the proximal and distal sections of the intestine relative to the resected area in acute mesenteric ischemia.

Prospects of Intraoperative Multimodal OCT Application in Patients with Acute Mesenteric Ischemia

INTRODUCTION

Despite the introduction of increasingly multifaceted diagnostic techniques and the general advances in emergency abdominal and vascular surgery, the outcome of treatment of patients with acute impaired intestinal circulation remains unsatisfactory. The non-invasive and high-resolution technique of optical coherence tomography (OCT) can be used intraoperatively to assess intestine viability and associated conditions that frequently emerge under conditions of impaired blood circulation. This study aims to demonstrate the effectiveness of multimodal (MM) OCT for intraoperative diagnostics of both the microstructure (cross-polarization OCT mode) and microcirculation (OCT angiography mode) of the small intestine wall in patients with acute mesenteric ischemia (AMI).

METHODS AND PARTICIPANTS

A total of 18 patients were enrolled in the study. Nine of them suffered from AMI in segments II-III of the superior mesenteric artery (AMI group), whereby the ischemic segments of the intestine were examined. Nine others were operated on for adenocarcinoma of the colon (control group), thus allowing areas of their normal small intestine to be examined for comparison. Data on the microstructure and microcirculation in the walls of the small intestine were obtained intraoperatively from the side of the serous membrane using the MM OCT system (IAP RAS, Russia) before bowel resection. The MM OCT data were compared with the results of histological examination.

RESULTS

The study finds that MM OCT visualized the damage to serosa, muscularis externa, and blood vessels localized in these layers in 100% of AMI cases. It also visualized the submucosa in 33.3% of AMI cases. The MM OCT images of non-ischemic (control group), viable ischemic, and necrotic small intestines (AMI group) differed significantly across stratification of the distinguishable layers, the severity of intermuscular fluid accumulations, and the type and density of the vasculature.

CONCLUSION

The MM OCT diagnostic procedure optimally meets the requirements of emergency surgery. Data on the microstructure and microcirculation of the intestinal wall can be obtained simultaneously in real time without requiring contrast agent injections. The depth of visualization of the intestinal wall from the side of the serous membrane is sufficient to assess the volume of the affected tissues. However, the methodology for obtaining MM OCT data needs to be improved to minimize the motion artefacts generated in actual clinical conditions.