The attenuation value of preoperative computed tomography as a novel predictor for pancreatic fistula after pancreaticoduodenectomy

Preoperative Fistula Risk Prediction Using Computed Tomography Image Before Pancreatoduodenectomy

BACKGROUND

Although many formulas for predicting postoperative pancreatic fistula (POPF) have been introduced, POPF is generally predicted during pancreatic surgery due to pancreatic texture. This study was designed to verify the correlation between Hounsfield units (HU) and pancreatic texture and to suggest a fistula risk score (FRS) that can be used before surgery.

METHODS

Data from 545 patients who underwent pancreatoduodenectomy for malignant disease between January 2008 and December 2019 were retrospectively reviewed. The HU level of the pancreas was measured, and odds ratio (OR) of the HU for POPF was analyzed. Additionally, the assessed HU was compared with the pancreatic texture (soft vs. hard) and calculated cutoff level. Finally, the preoperatively chosen pancreatic texture according to HU level was applied to the FRS formula (preoperative-FRS: p-FRS), and the results were compared with a previously reported FRS formula (updated alternative-FRS: ua-FRS).

RESULTS

The Hounsfield unit levels were correlated with clinically relevant POPF (CR-POPF) (odds ratio [OR]: 1.04 (1.01-1.07), p = 0.015). In the receiver operating characteristic curve, the HU showed significant prediction potential for pancreatic texture (area under the curve [AUC]: 0.744, p < 0.001). The p-FRS also showed acceptable results in predicting CR-POPF (AUC = 0.702, p < 0.001). There was no statistically significant difference in the DeLong's test compared with the ua-FRS (p = 0.314). In the Hosmer-Lemeshow test, observed probabilities were correlated with predicted probabilities (p = 0.596).

CONCLUSIONS

The HU level on preoperative computed tomography (CT) is a predictive factor for POPF and could represent for pancreatic texture.

Drain fluid biomarkers for prediction and diagnosis of clinically relevant postoperative pancreatic fistula: A narrative review

Clinically relevant postoperative pancreatic fistula (CR-POPF) has continued to compromise patient recovery post-pancreatectomy despite decades of research seeking to improve risk prediction and diagnosis. The current diagnostic criteria for CR-POPF requires elevated drain fluid amylase to present alongside POPF-related complications including infection, haemorrhage and organ failure. These worrying sequelae necessitate earlier and easily obtainable biomarkers capable of reflecting evolving CR-POPF. Drain fluid has recently emerged as a promising source of biomarkers as it is derived from the pancreas and hence, capable of reflecting its postoperative condition. The present review aims to summarise the current knowledge of CR-POPF drain fluid biomarkers and identify gaps in the field to invigorate future research in this critical area of clinical need. These findings may provide robust diagnostic alternatives for CR-POPF and hence, to clarify their clinical utility require further reports detailing their diagnostic and/or predictive accuracy.

Histological pancreatic findings correlate with computed tomography attenuation and predict postoperative pancreatic fistula following pancreatoduodenectomy

BACKGROUND

Although a soft pancreas is a widely-accepted reliable risk factor for postoperative pancreatic fistula (POPF) after pancreatoduodenectomy (PD), there is no established preoperative evaluation of pancreatic texture.

METHODS

Two hundred thirty-seven patients who underwent PD with histological pancreatic assessment were retrospectively enrolled. The degree of fibrosis and fatty infiltration was scored histologically as seven grades and five grades, respectively. Computed tomography (CT) attenuation of the pancreas was measured on preoperative unenhanced CT images. Correlations between the CT attenuation of the pancreas and the histological pancreatic findings, and the development of POPF were analyzed.

RESULTS

The fibrosis grade was significantly higher for hard pancreas than for soft pancreas (p < 0.001), whereas the fatty infiltration grade was similar between the two types (p = 0.161). CT attenuation of the pancreas was inversely correlated with both fibrosis grade (Spearman's rank correlation coefficient ([r] = -0.609, p < 0.001) and fatty infiltration grade (r = -0.382, p < 0.001). Multivariate analysis showed that body mass index ≥25 kg/m² (odds ratio [OR]: 5.64, p < 0.001) and fibrosis grade ≤2 (OR: 18.0, p < 0.001) were independent risk factors for clinically significant POPF.

CONCLUSION

Histological pancreatic texture can be evaluated with CT attenuation and might be helpful in preoperatively predicting the development of POPF after PD.

Estimated functional remnant pancreatic volume predicts nonalcoholic fatty liver disease after pancreaticoduodenectomy: use of computed tomography attenuation value of the pancreas

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is a late complication of pancreaticoduodenectomy (PD). However, this complication is difficult to predict preoperatively. This study aimed to assess the association between NAFLD and preoperative computed tomography (CT) findings.

METHODS

Medical records of 112 patients who had undergone PD and had CT scans preoperatively and 6 months postoperatively were retrospectively reviewed. We evaluated several CT findings, including the CT attenuation value of the remnant pancreas, remnant pancreatic volume (RPV), and the estimated functional remnant pancreatic volume (eFRPV) on preoperative CT. The variables, including the CT findings and histopathological findings, were compared between the patients with and without NAFLD after PD.

RESULTS

The NAFLD group included 21 patients (18.8%). The CT attenuation value of the remnant pancreas was correlated with the pancreatic acinar cell density (r = 0.537), and was lower in the NAFLD group than in the non-NAFLD group (p = 0.007). The eFRPV was lower in the NAFLD group than in the non-NAFLD group (p = 0.002). An eFRPV ≤47 mL·HU was an independent predictive factor for NAFLD (p = 0.007; odds ratio: 6.73; 95% confidence interval: 1.70-26.70).

CONCLUSION

The eFRPV can be used to preoperatively predict NAFLD after PD.

Relation of computed tomography features of the pancreatic tissue and development of pancreatic fistula after pancreaticoduodenectomy

BACKGROUND

Pancreatic density and steatosis detected in pre-operative computed tomography (CT) may be a risk factor for PF development after pancreatoduodenectomy (PD). There is insufficient data available on the relationship between PF and atherosclerosis in pancreatic vasculature of pancreatitis. This study aims to investigate whether PF development in patients undergoing PD can be predicted by preoperative CT findings.

MATERIAL-METHOD

Pancreas and spleen densities were measured on non-contrast CT images and pancreatic index (PI) was calculated to detect pancreatic steatosis. Pancreatic density and Wirsung diameter (WD) were measured on portal venous phase. Pancreatic fistulae were identified as biochemical leak (BL), grade B and grade C using ISGPF classification. The findings were compared between the fistula and non-fistula groups and ISGPF subgroups.

RESULTS

Of 148 patients, PF was detected on 31 (20.9%). In PF group, mean pancreatic density and PI were significantly lower than non-PF group, while pancreatic steatosis was detected at a higher rate. The WD was significantly narrower in the PF group. No significant relationship was found between the development of PF and the findings of atherosclerosis in the CT and SMA or acute pancreatitis. There was no significant difference between the PF subgroups for pancreas density.

CONCLUSION

In preoperative CT examinations, measuring the pancreatic density, PI index and WD can be used as a noninvasive quantitative method to predict the possibility of postoperative PF development.

Postoperative hyperamylasemia (POH) and acute pancreatitis after pancreatoduodenectomy (POAP): State of the art and systematic review

BACKGROUND

Postoperative hyperamylasemia is a frequent finding after pancreatoduodenectomy, but its incidence and clinical implications have not yet been analyzed systematically. The aim of this review is to reappraise the concept of postoperative hyperamylasemia with postoperative acute pancreatitis, including its definition, interpretation, and correlation.

METHODS

Online databases were used to search all available relevant literature published through June 2019. The following search terms were used: "pancreaticoduodenectomy," "amylase," and "pancreatitis." Surgical series reporting data on postoperative hyperamylasemia or postoperative acute pancreatitis were selected and screened.

RESULTS

Among 379 screened studies, 39 papers were included and comprised data from a total of 9,220 patients. Postoperative hyperamylasemia was rarely defined in most of these series, and serum amylase values were measured at different cutoff levels and reported on different postoperative days. The actual levels of serum amylase activity and the representative cutoff levels required to reach a diagnosis of postoperative acute pancreatitis were markedly greater on the first postoperative days and tended to decrease over time. Most studies analyzing postoperative hyperamylasemia focused on its correlation with postoperative pancreatic fistula and other postoperative morbidities. The incidence of postoperative acute pancreatitis varied markedly between studies, with its definition completely lacking in 40% of the analyzed papers. A soft pancreatic parenchyma, a small pancreatic duct, and pathology differing from cancer or chronic pancreatitis were all predisposing factors to the development of postoperative hyperamylasemia.

CONCLUSION

Postoperative hyperamylasemia has been proposed as the biochemical expression of pancreatic parenchymal injury related to localized ischemia and inflammation of the pancreatic stump. Such phenomena, analogous to those associated with acute pancreatitis, could perhaps be renamed as postoperative acute pancreatitis from a clinical standpoint. Patients with postoperative acute pancreatitis experienced an increased rate of all postoperative complications, particularly postoperative pancreatic fistula. Taken together, the discrepancies among previous studies of postoperative hyperamylasemia and postoperative acute pancreatitis outlined in the present review may provide a basis for stronger evidence necessary for the development of universally accepted definitions for postoperative hyperamylasemia and postoperative acute pancreatitis.

A deep pancreas is a novel predictor of pancreatic fistula after pancreaticoduodenectomy in patients with a nondilated main pancreatic duct

BACKGROUND

We investigated the risk factors for clinically relevant postoperative pancreatic fistula after pancreaticoduodenectomy in patients with a nondilated main pancreatic duct.

METHODS

We investigated a total of 354 patients who underwent pancreaticoduodenectomy. The diameter of the main pancreatic duct, the shortest distance from the body surface to the pancreas (the pancreatic depth), and the computed tomography attenuation index (the difference between the pancreatic and splenic computed tomography attenuation) were measured in preoperative computed tomography.

RESULTS

One hundred eighty-one (51.1%) patients had a nondilated main pancreatic duct, and 50 (27.6%) of the 181 patients with a nondilated main pancreatic duct developed a clinically relevant postoperative pancreatic fistula. Univariate analyses revealed that the calculated body mass index (≥21.8 kg/m²) (P = .004), deep pancreas (pancreatic depth ≥51.2 mm) (P = .001), and low computed tomography attenuation index (≤-3.8 Hounsfield units) (P = .02) were significant risk factors for clinically relevant postoperative pancreatic fistula. The multivariate logistic regression analysis revealed that deep pancreas (odds ratio 2.370; 95% confidence interval 1.0019-5.590; P = .049) was an independent risk factor for clinically relevant postoperative pancreatic fistula. Among patients with a nondilated main pancreatic duct, deep pancreas (in comparison to patients without deep pancreas) was associated with male sex (72.7% vs 54.9%; P = .016), higher body mass index (22.5 kg/m² vs 19.6 kg/m²; P < .001), a history of diabetes mellitus (24.5% vs 8.5%; P = .006), a lower computed tomography attenuation index (-9.6 Hounsfield units vs -4.6 Hounsfield units; P = .007), a longer operative time (454 minutes vs 420 minutes; P = .007), and a higher volume of intraoperative blood loss (723 mL vs 500 mL; P < .001), respectively.

CONCLUSION

Deep pancreas may be an important parameter associated with significant risk factors for clinically relevant postoperative pancreatic fistula after pancreaticoduodenectomy in patients with a nondilated main pancreatic duct.

Risk factors and preventive measures for postoperative pancreatic fistula after pancreaticoduodenectomy

Postoperative pancreatic fistula (POPF) is the most serious complication after pancreaticoduodenectomy (PD), which can lead to slow recovery, deterioration, and even reoperation and death. At present, the mortality rate after PD has decreased, but the incidence of POPF is still high. Therefore, exploring the risk factors and prevention strategies for pancreatic fistula has become a hot research topic in pancreatic surgery. This paper summarizes the nature, risk factors, and preventive measures for POPF.

The individualized selection of Pancreaticoenteric anastomosis in Pancreaticoduodenectomy

Background

The mortality following pancreaticoduodenectomy has markedly decreased but remains an important challenge for the complexity of operation and technical skills involved. The present study aimed to clarify the impact of individualized pancreaticoenteric anastomosis and management to postoperative pancreatic fistula.

Methods

Data from 529 consecutive pancreaticoduodenectomies were retrospectively analysed from the Hepatobiliary and Pancreatic Surgery Unit I, Peking Cancer Hospital. The pancreaticoenteric anastomosis was determined based on the pancreatic texture and diameter of the main pancreatic duct. The amylase value of the drainage fluid was dynamically monitored postoperatively on days 3, 5 and 7. A low speed intermittent irrigation was performed in selected patients. Intraoperative and postoperative results were collected and compared between the pancreaticogastrostomy (PG) group and pancreaticojejunostomy (PJ) group.

Results

From 2010 to 2019, 529 consecutive patients underwent pancreaticoduodenectomy. Pancreaticogastrostomy was performed in 364 patients; pancreaticojejunostomy was performed in 150 patients respectively. The clinically relevant pancreatic fistula (CR-POPF) was 9.8% and mortality was zero. The soft pancreas, diameter of main pancreatic duct≤3 mm, BMI ≥ 25, operation time > 330 min and pancreaticogastrostomy was correlated with postoperative pancreatic fistula significantly. The CR-POPF of PJ was significantly higher than that of PG in soft pancreas patients; the operation time of PJ was shorter than that of PG significantly in hard pancreas patients. Intraoperative blood loss and operation time of PG was less than that of PJ significantly in normal pancreatic duct patients (p < 0.05).

Conclusions

Individualized pancreaticoenteric anastomosis should be determined based on the pancreatic texture and pancreatic duct diameter. The appropriate anastomosis and postoperative management could prevent mortality.