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Laser speckle contrast imaging identifies ischemic areas on gastric tube reconstructions following esophagectomy

View Article: PubMed Central - PubMed

ABSTRACT

S: Gastric tube reconstruction (GTR) is a high-risk surgical procedure with substantial perioperative morbidity. Compromised arterial blood supply and venous congestion are believed to be the main etiologic factors associated with early and late anastomotic complications. Identifying low blood perfusion areas may provide information on the risk of future anastomotic leakage and could be essential for improving surgical techniques. The aim of this study was to generate a method for gastric microvascular perfusion analysis using laser speckle contrast imaging (LSCI) and to test the hypothesis that LSCI is able to identify ischemic regions on GTRs.

Patients requiring elective laparoscopy-assisted GTR participated in this single-center observational investigation. A method for intraoperative evaluation of blood perfusion and postoperative analysis was generated and validated for reproducibility. Laser speckle measurements were performed at 3 different time pointes, baseline (devascularized) stomach (T0), after GTR (T1), and GTR at 20° reverse Trendelenburg (T2).

-: Blood perfusion analysis interrater reliability was high, with intraclass correlation coefficients for each time point approximating 1 (P < 0.0001). Baseline (T0) and GTR (T1) mean blood perfusion profiles were highest at the base of the stomach and then progressively declined towards significant ischemia at the most cranial point or anastomotic tip (P < 0.01). After GTR, a statistically significant improvement in mean blood perfusion was observed in the cranial gastric regions of interest (P < 0.05). A generalized significant decrease in mean blood perfusion was observed across all GTR regions of interest during 20° reverse Trendelenburg (P < 0.05).

It was feasible to implement LSCI intraoperatively to produce blood perfusion assessments on intact and reconstructed whole stomachs. The analytical design presented in this study resulted in good reproducibility of gastric perfusion measurements between different investigators. LSCI provides spatial and temporal information on the location of adequate tissue perfusion and may thus be an important aid in optimizing surgical and anesthesiological procedures for strategically selecting anastomotic site in patients undergoing esophagectomy with GTR.

No MeSH data available.


Supplementary intraoperative data from 1 patient illustrating the effects of administering ephedrine for treating low blood pressure on the most ischemic regions of the gastric tube during 20° reverse Trendelenburg. Flux perfusion measured by LSCI increased significantly from before (A) to after administering ephedrine (B) across all regions of interest (C), extending from the watershed towards the cranial (fundus) anastomotic tip. LSCI = laser speckle contract imaging.
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Figure 4: Supplementary intraoperative data from 1 patient illustrating the effects of administering ephedrine for treating low blood pressure on the most ischemic regions of the gastric tube during 20° reverse Trendelenburg. Flux perfusion measured by LSCI increased significantly from before (A) to after administering ephedrine (B) across all regions of interest (C), extending from the watershed towards the cranial (fundus) anastomotic tip. LSCI = laser speckle contract imaging.

Mentions: Determining borders between highly vital and less vital (ischemic) tissue regions could help the surgeon intraoperatively to identify adequate locations for an anastomosis. Furthermore, full-field perfusion maps may support intraoperative fluid and vasomodulation more efficiently[25–29]; an example of this in 1 patient is presented in a supplementary graph (Fig. 4) showing the effects of administering ephedrine to treat low blood pressure, where flux perfusion measured by LSCI increased significantly. The use of local nitroglycerine improved microcirculation in some studies, but the use of vasoconstrictors aiming solely at improving perfusion pressure is doubtful.[13,27,29] LSCI may provide valuable information regarding correlations between cardiac output and targeted visceral organs. Although most patients received chemoradiation, only 6 patients had their fundus irradiated. It was not possible to obtain intact healthy human stomach speckle-based datasets for comparison between devascularized and/or irradiated stomachs. It would have been a great advantage to obtain comparative data from healthy intact human stomach. We did not find any indications of affected microcirculatory flow in patients after radiation therapy on the fundus. This can be interpreted as either 1 of the 2 possibilities: (1) LSCI is not sensitive enough to detect more subtle changes, or (2) chemoradiation does not affect microcirculatory flow, and adverse outcome is caused by other complications such as changes in autonomic regulation of blood flow (divergence of flow), decreased regenerating capacity of cells, or long-term changes in tissue regeneration. Nonetheless, without healthy in situ stomach datasets for comparison, it remains difficult to interpret the impact of irradiation on fundus microvascular perfusion.


Laser speckle contrast imaging identifies ischemic areas on gastric tube reconstructions following esophagectomy
Supplementary intraoperative data from 1 patient illustrating the effects of administering ephedrine for treating low blood pressure on the most ischemic regions of the gastric tube during 20° reverse Trendelenburg. Flux perfusion measured by LSCI increased significantly from before (A) to after administering ephedrine (B) across all regions of interest (C), extending from the watershed towards the cranial (fundus) anastomotic tip. LSCI = laser speckle contract imaging.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4998312&req=5

Figure 4: Supplementary intraoperative data from 1 patient illustrating the effects of administering ephedrine for treating low blood pressure on the most ischemic regions of the gastric tube during 20° reverse Trendelenburg. Flux perfusion measured by LSCI increased significantly from before (A) to after administering ephedrine (B) across all regions of interest (C), extending from the watershed towards the cranial (fundus) anastomotic tip. LSCI = laser speckle contract imaging.
Mentions: Determining borders between highly vital and less vital (ischemic) tissue regions could help the surgeon intraoperatively to identify adequate locations for an anastomosis. Furthermore, full-field perfusion maps may support intraoperative fluid and vasomodulation more efficiently[25–29]; an example of this in 1 patient is presented in a supplementary graph (Fig. 4) showing the effects of administering ephedrine to treat low blood pressure, where flux perfusion measured by LSCI increased significantly. The use of local nitroglycerine improved microcirculation in some studies, but the use of vasoconstrictors aiming solely at improving perfusion pressure is doubtful.[13,27,29] LSCI may provide valuable information regarding correlations between cardiac output and targeted visceral organs. Although most patients received chemoradiation, only 6 patients had their fundus irradiated. It was not possible to obtain intact healthy human stomach speckle-based datasets for comparison between devascularized and/or irradiated stomachs. It would have been a great advantage to obtain comparative data from healthy intact human stomach. We did not find any indications of affected microcirculatory flow in patients after radiation therapy on the fundus. This can be interpreted as either 1 of the 2 possibilities: (1) LSCI is not sensitive enough to detect more subtle changes, or (2) chemoradiation does not affect microcirculatory flow, and adverse outcome is caused by other complications such as changes in autonomic regulation of blood flow (divergence of flow), decreased regenerating capacity of cells, or long-term changes in tissue regeneration. Nonetheless, without healthy in situ stomach datasets for comparison, it remains difficult to interpret the impact of irradiation on fundus microvascular perfusion.

View Article: PubMed Central - PubMed

ABSTRACT

S: Gastric tube reconstruction (GTR) is a high-risk surgical procedure with substantial perioperative morbidity. Compromised arterial blood supply and venous congestion are believed to be the main etiologic factors associated with early and late anastomotic complications. Identifying low blood perfusion areas may provide information on the risk of future anastomotic leakage and could be essential for improving surgical techniques. The aim of this study was to generate a method for gastric microvascular perfusion analysis using laser speckle contrast imaging (LSCI) and to test the hypothesis that LSCI is able to identify ischemic regions on GTRs.

Patients requiring elective laparoscopy-assisted GTR participated in this single-center observational investigation. A method for intraoperative evaluation of blood perfusion and postoperative analysis was generated and validated for reproducibility. Laser speckle measurements were performed at 3 different time pointes, baseline (devascularized) stomach (T0), after GTR (T1), and GTR at 20° reverse Trendelenburg (T2).

-: Blood perfusion analysis interrater reliability was high, with intraclass correlation coefficients for each time point approximating 1 (P < 0.0001). Baseline (T0) and GTR (T1) mean blood perfusion profiles were highest at the base of the stomach and then progressively declined towards significant ischemia at the most cranial point or anastomotic tip (P < 0.01). After GTR, a statistically significant improvement in mean blood perfusion was observed in the cranial gastric regions of interest (P < 0.05). A generalized significant decrease in mean blood perfusion was observed across all GTR regions of interest during 20° reverse Trendelenburg (P < 0.05).

It was feasible to implement LSCI intraoperatively to produce blood perfusion assessments on intact and reconstructed whole stomachs. The analytical design presented in this study resulted in good reproducibility of gastric perfusion measurements between different investigators. LSCI provides spatial and temporal information on the location of adequate tissue perfusion and may thus be an important aid in optimizing surgical and anesthesiological procedures for strategically selecting anastomotic site in patients undergoing esophagectomy with GTR.

No MeSH data available.