Postoperative Complications of Laparoscopic Cholecystectomy for Acute Cholecystitis: A Comparison to the ACS-NSQIP Risk Calculator and the Tokyo Guidelines

Predictive value of the American college of surgeons "surgical risk calculator" (ACS-NSQIP SRC) for plastic and reconstructive surgery: a validation study from an academic tertiary referral center in Germany

AIMS

The American College of Surgeons Surgical Risk Calculator (ACS-NSQIP SRC) was designed to predict morbidity and mortality in order to help providing informed consent. This study evaluated its performance in the field of plastic and reconstructive surgery for patients undergoing body contouring and breast reconstruction procedures.

METHODS

A retrospective analysis of patients undergoing body contouring and breast reconstruction procedures from January 1, 2022 to November 1, 2024 was performed.

RESULTS

The ACS-NSQIP SRC showed good prediction only for severe complications in patients undergoing breast reconstruction with DIEP flap (AUC = 0.727); overall prediction and calibration for the remaining 15 subgroups was poor. The incidence of overall and general complications, as well as length of hospital stay was underestimated.

CONCLUSIONS

The overall performance of the ACS-NSQIP SRC was poor, a finding that underlines the importance of individual decision-making, also considering the surgeon's expertise and patient-specific characteristics.

Outcome prediction after emergency cholecystectomy: performance evaluation of the ACS-NSQIP surgical risk calculator and the 5-item modified frailty index

Pre-operative risk assessment tools and frailty scores are increasingly common due to the growing number of elderly, comorbid and frail patients. This study aims to assess the performance of the ACS-NSQIP-SRC (American College of Surgeons- National Surgical Quality Improvement Program- Surgical Risk Calculator) and the 5mFI (5-items modified Frailty Index) in predicting clinical outcomes after emergency cholecystectomy. This is a retrospective cohort study of patients with acute calculous cholecystitis admitted at our tertiary care center from 2018 to 2023. We evaluated discrimination, calibration, and accuracy of the ACS-NSQIP-SRC and 5mFI in predicting any complication, mortality, length of hospital stay (LOS), need for readmission and supported discharge (30-day follow-up). Among 365/642 patients who underwent surgery, the 5mFI showed poor discrimination for all outcomes but good overall accuracy in the prediction of a supported discharge. In 198 operated patients with available data for the ACS-NSQIP-SRC, it underestimated complications and need for readmission while overestimated the need for supported discharge. There was no concordance between predicted and observed LOS. Among 277/642 patients undergoing non-operative management, 2/3 were frail or mild frail and had a predicted rate of any unfavorable outcome after surgery between 0 and 20%, being 95% above the average risk of each outcome. Mortality couldn't be studied because no death was reported. ACS-NSQIP-SRC and 5mFI performance in predicting outcomes after emergency cholecystectomy for acute cholecystitis was poor. In the emergency cholecystectomy setting, the ACS-NSQIP-SRC may be less informative, and the 5mFI may be excessively simplistic by neglecting the multidimensional nature of frailty.

Evaluation of the ACS NSQIP surgical risk calculator in patients undergoing common bile duct exploration

PURPOSE

The American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) surgical risk calculator is a risk stratification tool to help predict risks of postoperative complications, which is important for informed decision-making. The purpose of this study was to evaluate the accuracy of the calculator in predicting postoperative complications in patients undergoing common bile duct (CBD) exploration.

METHODS

A retrospective chart review was completed for 305 patients that underwent open and laparoscopic CBD exploration at a single institution from 2010 to 2018. Patient demographics and preoperative risk factors were entered into the calculator, and the predicted complication risks were compared with observed complication rates. Brier score, C-statistic, and Hosmer-Lemeshow regression analysis were used to assess discrimination and calibration.

RESULTS

The observed rate exceeded the predicted rate for any complication (35.1% vs. 21%), return to operating room (5.9% vs. 3.6%), death (3.3% vs. 1%), and sepsis (3% vs. 2.4%). The model performed best in predicting serious complication (Brier 0.087, C-statistic 0.818, Hosmer-Lemeshow 0.695), surgical site infection (Brier 0.068, C-statistic 0.670, Hosmer-Lemeshow 0.292), discharge to rehabilitation facility (Brier 0.041, C-statistic 0.907, Hosmer-Lemeshow 0.638), and death (Brier 0.028, C-statistic 0.898, Hosmer-Lemeshow 0.004). In multivariable analysis, there was no statistically significant predicted complication type that affected the type of surgery.

CONCLUSION

The calculator was accurate in predicting serious complication, surgical site infection, discharge to rehabilitation facility, and death. However, the model displayed poor predictive ability in all other complications that were analyzed.

Fast-Track Nonelective Laparoscopic Cholecystectomy is Safe and Feasible

INTRODUCTION

Ample evidence exists to support the safety of fast-track discharge after elective laparoscopic cholecystectomy (LC), but there is currently no data available to support the safety of fast-tracking patients undergoing nonelective LC. We sought to determine whether fast-tracking patients undergoing nonelective LC is safe and feasible.

METHODS

We performed a retrospective cohort review of 661 consecutive patients undergoing LC at a single teaching institution from April 2018 to January 2020. Subjects were divided into two groups: elective LC (ELC) and fast-track nonelective LC (FTLC). FTLC was defined as nonelective LC with total length of stay <36 h. Patients undergoing nonelective LC with length of stay exceeding 36 h were excluded. The primary outcome of interest was readmission within 30 d. The secondary outcomes included incidences of return to emergency department within 30 d, retained stone, bile leak, and wound infection.

RESULTS

Of 661 LC, 185 (27%) were ELC and 476 (72%) were nonelective. FTLC included 121 (25%) of the nonelective LC. Preoperative characteristics were similar among the groups. On final pathology, chronic cholecystitis was predominant in both groups, but FTLC exhibited higher rates of acute cholecystitis (P < 0.0001). There was no significant difference in the primary outcome among groups: readmission within 30 d occurred in 6 (3%) ELC patients and 4 (3%) FTLC patients (P = 1.0). There were no significant differences in rates of return to emergency department within 30 d, retained stone, bile leak, or wound infection.

CONCLUSIONS

With comparable postoperative complication rates to ELC, FTLC can be safely used in select patients. Additional studies are needed to determine preoperative predictors of FTLC suitability to prospectively identify appropriate patients.

Forecasting outcomes after cholecystectomy in octogenarian patients

BACKGROUND

Although gallstone disease increases with aging, elderly patients are less likely to undergo cholecystectomy. This is because age itself is a negative predictor after cholecystectomy. The ACS-NSQIP risk calculator can therefore help surgeons decide whether to operate or not. However, little is known about the accuracy of this model outside the ACS National Surgical Quality Improvement Program. The aim of the present study is to evaluate the ability of the ACS-NSQIP model to predict the clinical outcomes of patients aged 80 years or older undergoing elective or emergency cholecystectomy.

STUDY DESIGN

The study focused on 263 patients over 80 years of age operated on between 2010 and 2019: 174 were treated as emergencies because of acute cholecystitis (66.2%). Outcomes evaluated are those predicted by the ACS-NSQIP calculator within 30 days of surgery. The ACS-NSQIP model was tested for both discrimination and calibration. Differences among observed and expected outcomes were evaluated.

RESULTS

When considering all patients, the discrimination of mortality was very high, as it was that of severe complications. Considering only the elective cholecystectomies, the discrimination capacity of ACS-NSQIP risk calculator has consistently worsened in each outcome while it remains high considering the emergency cholecystectomies. In the evaluation of the emergency cholecystectomy, the model showed a very high discriminatory ability and, more importantly, it showed an excellent calibration. Comparisons between main outcomes showed small or even negligible differences between observed and expected values.

CONCLUSION

The results of the present study suggest that clinical decisions on cholecystectomy in a patient aged 80 years or older should be assisted through the ACS-NSQIP model.

Acute cholecystitis: Delayed cholecystectomy has lesser perioperative morbidity compared to emergency cholecystectomy

BACKGROUND

In comparison to delayed laparoscopic cholecystectomy, emergency laparoscopic cholecystectomy has a shorter length of stay and eliminates the risk of recurrent episodes of acute cholecystitis. Nevertheless, there is concern that emergency laparoscopic cholecystectomy is associated with higher morbidity in acute cholecystitis patients. The present large cohort study compares operation-related adverse outcomes between emergency and delayed laparoscopic cholecystectomy and determines the risk of readmission before delayed laparoscopic cholecystectomy to guide surgical decision-making.

METHODS

Patients diagnosed with acute cholecystitis who underwent emergency or delayed laparoscopic cholecystectomy between 2015 and 2019 were included. Perioperative outcomes were compared using univariate and multivariate analysis, adjusting for preoperative variables. The rate of readmission before delayed laparoscopic cholecystectomy was determined.

RESULTS

In total, 811 patients were included (median age, 58 years; male:female, 1:1.5): 227 emergency laparoscopic cholecystectomies (28.0%), 555 delayed laparoscopic cholecystectomies (68.4%), and 29 emergency laparoscopic cholecystectomies whilst awaiting delayed laparoscopic cholecystectomy (3.6%). Emergency laparoscopic cholecystectomy was associated with increased incidences of subtotal cholecystectomy (OR 1.94; P = .011), bile leak (OR 2.38; P = .013), intraoperative drains (OR 2.54; P < .001), prolonged postoperative length of stay (OR 7.26; P < .001), postoperative imaging (OR 1.83, P = .006), and postoperative readmission (OR 1.90; P = .005). There was a 13.5% risk of readmission over 2 months while waiting delayed laparoscopic cholecystectomy and a 22.5% risk over the median waiting time (5 months, 9 days).

CONCLUSION

Emergency laparoscopic cholecystectomy is positively associated with a multitude of operation-related adverse outcomes in acute cholecystitis, compared to delayed laparoscopic cholecystectomy. The benefit of delayed laparoscopic cholecystectomy should be balanced against the significant readmission risk before delayed laparoscopic cholecystectomy. Emergency laparoscopic cholecystectomy may be the most pragmatic strategy for centers dealing with high volumes of biliary admissions and long elective-surgery waiting times. When opting for delayed laparoscopic cholecystectomy, confirming the date of surgery before discharge may ensure timely intervention and avoid the morbidity and expense of readmission.

Predicted versus actual complications in Australian women undergoing post-mastectomy breast reconstruction: a retrospective cohort study using the BRA Score tool

INTRODUCTION

The Breast Reconstruction Risk Assessment (BRA) Score tool is a risk calculator developed to predict the risk of complications in individual patients undergoing breast reconstruction. It was developed in a North American population exclusively undergoing immediate breast reconstruction. This study sought to assess the predictions of the BRA Score tool against the measured outcomes of surgery for an Australian public hospital population, including both immediate and delayed reconstructions.

METHOD

This was a retrospective cohort study of data from women at a single Australian public teaching hospital unit. Data from the Flinders Breast Reconstruction Database was retrieved and compared to BRA Scores calculated for each patient. Receiver operating curve area under the curve analysis was performed as well as Brier scores to compare predicted versus observed complications.

RESULTS

BRA Score predictions were reasonable or good (C-statistic >0.7, Brier score <0.09) for the complications of overall surgical complications, surgical site infection (SSI) and seroma at 30 days, and similarly accurate for prediction of the same complications for implant reconstructions at 12 months. There were similar findings between delayed and immediate reconstructions.

CONCLUSION

The BRA Score risk calculator is valid to detect some risks in both patients undergoing immediate and delayed breast reconstruction in an Australian public hospital setting. SSI is the best predicted complication and is well-predicted across both autologous and prosthetic reconstruction types.

A Simple Risk Score to Predict Clavien-Dindo Grade IV and V Complications After Non-elective Cholecystectomy

BACKGROUND

Non-elective cholecystectomies can lead to severe postoperative complications and mortality. Existing risk prediction tools do not meet the need to reliably predict these complications.

METHODS

Using the 2011-2016 American College of Surgeons National Surgical Quality Improvement Program datasets, we identified patients undergoing non-elective cholecystectomy with primary ICD 9/10 codes indicating the following diagnoses: symptomatic cholelithiasis, acute cholecystitis, choledocholithiasis, gallstone pancreatitis, and cholangitis. We randomly allocated patients to derivation and validation cohorts (80/20 split). Severe complications (Clavien-Dindo grades IV and V) included unplanned intubation, prolonged mechanical ventilation, pulmonary embolism, acute renal failure requiring dialysis, stroke, myocardial infarction, cardiac arrest, septic shock, and mortality. Logistic regression using backward selection identified predictors of severe complications and a risk score was generated based on this model.

RESULTS

Of 68,953 patients in the derivation cohort, 1.7% (N = 1157) suffered severe complications. The final multivariable risk score model included the following predictors: age (0-12 points), preoperative sepsis (5 points), planned open procedure (5 points), estimated glomerular filtration rate (0-13 points), and preoperative albumin level (0-8 points). The associated risk-score model yielded scores from 0 to 43 with 0.1-59.4% predicted probability of severe complications and had a C-statistic of 0.845 (95% CI 0.834, 0.857) in the derivation cohort and 0.870 (95% CI 0.851, 0.889) in the validation cohort.

CONCLUSION

A simple risk-score model predicts severe complications in patients undergoing unplanned cholecystectomy for common indications encountered in an acute care surgery service and identifies high-risk patients.

Utilization of an Intraoperative Grading Scale in Laparoscopic Cholecystectomy: A Nepalese Perspective

INTRODUCTION

Difficult geographic diversity and late presentation to medical attention often make the laparoscopic cholecystectomy difficult and chances of conversion and complication remains. Various preoperative grading scales have been developed for predicting the difficulty of surgery in cholecystitis patients; however, intraoperative assessment of anatomical status and inflammation of the gall bladder has not been assessed till date except for some guidelines like the Parkland grading scale (PGS). We aimed to utilise this guideline in patients undergoing laparoscopic cholecystectomy in rural community of the developing nation.

METHODS

PGS was applied for all the patients undergoing laparoscopic cholecystectomy and laboratory and outcome factors like preoperative white blood cells (WBC), open conversion, subtotal cholecystectomy, length of surgery, and bile leaks postoperatively were assessed.

RESULTS

Among 178 patients who underwent cholecystectomy, there were 40 grade one GBs, 90 grade two GBs, 26 grade three GBs, 16 grade four GBs, and six grade five GBs. With a conversion rate of 6.74%, eight patients underwent subtotal cholecystectomy. Among them, four patients were graded as 5th grade, two as 4th grade, and two as 3rd grade according to PGS system. Postoperative bile leak was seen in three patients among which two were grade five GBs and one was grade four. Preoperative WBC, conversion to open, subtotal cholecystectomy, length of surgery, and postoperative bile leak all significantly increased with increasing grades (p < 0.05).

CONCLUSION

PGS can be applied in patients undergoing laparoscopic cholecystectomy in the rural setting of a developing nation. With its application, postoperative course could be predicted and adequate counselling can be done about the possibilities of the outcome.

Performance of the American College of Surgeons NSQIP Surgical Risk Calculator for Total Gastrectomy

BACKGROUND

To encourage implementation of the American College of Surgeons (ACS) NSQIP Risk Calculator for total gastrectomy for gastric cancer, its predictive performance for this specific procedure should be validated. We assessed its discriminatory accuracy and goodness of fit for predicting 12 adverse outcomes.

STUDY DESIGN

Data were collected on all patients with gastric cancer who underwent total gastrectomy with curative intent at Memorial Sloan Kettering Cancer Center between 2002 and 2017. Preoperative risk factors from the electronic medical record were manually inserted into the ACS-NSQIP Risk Calculator. Predictions for adverse outcomes were compared with observed outcomes by Brier scores, c-statistics, and Hosmer-Lemeshow p value.

RESULTS

In a total of 452 patients, the predicted rate of all complications (29%) was lower than the observed rate (45%). Brier scores varied between 0.017 for death and 0.272 for any complication. C-statistics were moderate (0.7-0.8) for death and renal failure, good (0.8-0.9) for cardiac complication, and excellent (≥0.9) for discharge to nursing or rehabilitation facility. Hosmer-Lemeshow p value found poor goodness of fit for pneumonia only.

CONCLUSIONS

For adverse outcomes after total gastrectomy with curative intent in gastric cancer patients, performance of the ACS-NSQIP Risk Calculator is variable. Its predictive performance is best for cardiac complications, renal failure, death, and discharge to nursing or rehabilitation facility.

Comparison of laparoscopic cholecystectomy and delayed laparoscopic cholecystectomy in aged acute calculous cholecystitis: a cohort study

BACKGROUND

In elderly patients with calculous acute cholecystitis, the risk of emergency surgery is high, and percutaneous cholecystostomy tube drainage (PC) combined with delayed laparoscopic cholecystectomy (DLC) may be a good choice. We retrospectively compared laparoscopic cholecystectomy (LC) to DLC after PC to determine which is the better treatment strategy.

METHOD

We performed a retrospective cohort analysis of 752 patients with acute calculous cholecystitis. Patients with the following conditions were included: (1) age > 65 years old; (2) patients with a grade 2 or 3 severity of cholecystitis according to the 2013 Tokyo Guidelines (TG13); (3) the surgeons who performed the LC were professors or associate professors and (4) the DLC was performed in our hospital after PC. Patients who missed their 30-day follow-up; were diagnosed with bile duct stones, cholangitis or gallstone pancreatitis or were pregnant were excluded from the study. A total of 51 of 314 patients who underwent LC and 73 of 438 patients who underwent PC + DLC were assessed. PC + DLC and LC patients were matched by cholecystitis severity grade according to the TG13, and the National Surgical Quality Improvement Program (NSQIP) calculator was used to predict mortality (n = 21/group). Preoperative characteristics and postoperative outcomes were analysed.

RESULTS

Compared to the matched LC group, the DLC group had less intraoperative bleeding (42.2 vs 75.3 mL, p = 0.014), shorter hospital stays (4.9 vs 7.4 days, p = 0.010) and lower rates of type A bile duct injury (4.8% vs 14.3%, p = 0.035) and type D (0 vs 9.5%, p = 0.002) according to Strasberg classification, residual stones (4.8 vs 14.3%, p = 0.035) and gastrointestinal organ injury (0 vs 3.6%, p < 0.001). Patients in the DLC group had lower incidences of ICU admission and death and a significantly lower incidence of repeat surgery.

CONCLUSION

In elderly patients treated for acute calculous cholecystitis, the 30-day mortality and complication rates were lower for PC + DLC than for LC. However, the total hospitalisation time was significantly prolonged and the costs were significantly higher for PC + DLC.

Evaluation of the Performance of ACS NSQIP Surgical Risk Calculator in Emergency General Surgery Patients

The ACS NSQIP Surgical Risk Calculator is designed to estimate the chance of an unfavorable outcome after surgery. Our goal was to evaluate the accuracy of the calculator in our emergency general surgery population. Surgical outcomes were compared to predicted risk. The risk was calculated with surgeon adjustment scores (SASs) of 1 (no adjustment), 2 (risk somewhat higher), and 3 (risk significantly higher than estimate). Two hundred and twenty-seven patients met the inclusion criteria. An SAS of 1 or 2 accurately predicted risk of mortality (5.7% and 8.5% predicted versus 7.9% actual), whereas a risk adjustment of 3 indicated significant overestimation of mortality rate (14.8% predicted). There was good overall prediction performance for most variables with no clear preference for SAS 1, 2, or 3. Poor correlation was seen with SSI, urinary tract infection, and length of stay variables. The ACS NSQIP Surgical Risk Calculator yields valid predictions in the emergency general surgery population, and the data support its use to inform conversations about outcome expectations.

Predicting Post-operative Complications in Crohn's Disease: an Appraisal of Clinical Scoring Systems and the NSQIP Surgical Risk Calculator

BACKGROUND

Surgery is common in patients with Crohn's disease and can contribute significantly to patient morbidity. The National Surgical Quality Improvement Program surgical risk calculator (NSQIP-SRC) that is currently utilized to predict surgical risk does not take Crohn's disease into account and, as a result, seems to underestimate risk in this patient population. This study aimed to evaluate the accuracy of the NSQIP-SRC in Crohn's disease patients and to evaluate the utility of disease severity scores in predicting surgical risk.

METHODS

Between 2011 and 2017, there were 176 surgical cases involving Crohn's disease patients. Demographic data and 30-day surgical outcomes were collected. Disease severity scores including Harvey Bradshaw Index (HBI), Crohn's Disease Activity Index (CDAI), Simple Endoscopic Score for Crohn's Disease (SES-CD), and NSQIP-SRC risk percentages were calculated.

RESULTS

Patients in remission based on HBI had a complication rate of 8.57% (n = 3), while those with mild or moderate-severe disease had rates of 33.33% (n = 11) and 38.46% (n = 20) respectively (p = 0.0045). In multivariable analysis, those with mild (OR; 8.37, 95% CI; 1.64, 42.78; p = 0.011) or moderate-severe (OR; 11.69, 95% CI; 2.42, 56.46; p = 0.002) disease had increased odds of complication compared to remission. Complication rate was not associated with NSQIP-SRC percent risk of any complication.

CONCLUSION

NSQIP-SRC does not accurately predict risk in patients with CD undergoing surgery. Higher disease activity based on HBI is associated with increased odds of complication and may prove to be more predictive of surgical complication in the Crohn's patient population.

Predicting Postoperative Complications after Acute Care Surgery: How Accurate is the ACS NSQIP Surgical Risk Calculator?

The ACS NSQIP Surgical Risk Calculator (SRC) is an evidence-based clinical tool commonly used for evaluating postoperative risk. The goal of this study was to validate SRC-predicted complications by comparing them with observed outcomes in the acute care surgical setting. In this study, pre- and postoperative data from 1693 acute care surgeries (hernia repair, enterolysis, intestinal incision/excision and enterectomy, gastrectomy, debridement, colectomy, appendectomy, cholecystectomy, gastrorrhaphy, and incision and drainage of soft tissue, breast abscesses, and removal of foreign bodies) performed at a Level I trauma center over a five-year time period were abstracted. Predictions for any and serious complications were based on SRC were compared with observed outcomes using various measures of diagnostic. When evaluated as one group, the SRC had good discriminative power for predicting any and serious complications after acute care surgeries (Area Under the Curve (AUC) 0.79, 0.81). In addition, the SRC met Brier score requirements for an informative model overall. However, the predictive accuracy of the SRC varied for various procedures within the acute care patient population. For serious complications, the diagnostic measures ranged from an AUC of 0.61 and negative likelihood ratio of 0.716 for incision & drainage soft tissue to AUC of 0.91 and negative likelihood ratio of 0.064 for gastrorrhaphy. Length of stay was significantly underestimated by the SRC overall (8.56 days, P < 0.01) and for individual procedures. The SRC performs well at predicting complications after acute care surgeries overall; however, there is great variability in performance between procedure types. Further refinements in risk stratification may improve SRC predictions.

Beyond 30 Days: A Risk Calculator for Longer Term Outcomes of Prosthetic Breast Reconstruction

Background

Despite growing use of surgical risk calculators, many are limited to 30-day outcomes due to the constraints of their underlying datasets. Because complications of breast reconstruction can occur well beyond 30 days after surgery, we endeavored to expand the Breast Reconstruction Risk Assessment (BRA) Score to prediction of 1-year complications after primary prosthetic breast reconstruction.

Methods

We examined our prospective intrainstitutional database of prosthetic breast reconstructions from 2004 to 2015. Patients without 1-year follow-up were excluded. Pertinent patient variables include those enumerated in past iterations of the BRA Score. Outcomes of interest include seroma, surgical site infection (SSI), implant exposure, and explantation occurring within 1 year of tissue expander placement. Risk calculators were developed for each outcome using multivariate logistic regression models and made available online at www.BRAScore.org. Internal validity was assessed using C-statistic, Hosmer-Lemeshow test, and Brier score.

Results

Nine-hundred three patients met inclusion criteria. Within 1-year, 3.0% of patients experienced seroma, 6.9% infection, 7.1% implant exposure, and 13.2% explantation. Thirty-day, 90-day, and 180-day windows captured 17.6%, 39.5%, and 59.7% of explantations, respectively. One-year risk calculators were developed for each complication of interest, and all demonstrated good internal validity: C-statistics for the 5 models ranged from 0.674 to 0.739, Hosmer-Lemeshow tests were uniformly nonsignificant, and Brier scores ranged from 0.027 to 0.154.

Conclusions

Clinically significant complications of prosthetic breast reconstruction usually occur beyond the 30-day window following tissue expander placement. To better reflect long-term patient experiences, the BRA Score was enhanced with individualized risk models that predicted 1-year complications after prosthetic reconstruction (BRA Score XL). All models performed as well as, if not better than, the original BRA Score models and other popular risk calculators such as the CHA₂DS₂VASc Score. The patient-friendly BRA Score XL risk calculator is available at www.brascore.org to facilitate operative decision-making and heighten the informed consent process for patients.

Development and validation of machine learning models to identify high-risk surgical patients using automatically curated electronic health record data (Pythia): A retrospective, single-site study

BACKGROUND

Pythia is an automated, clinically curated surgical data pipeline and repository housing all surgical patient electronic health record (EHR) data from a large, quaternary, multisite health institute for data science initiatives. In an effort to better identify high-risk surgical patients from complex data, a machine learning project trained on Pythia was built to predict postoperative complication risk.

METHODS AND FINDINGS

A curated data repository of surgical outcomes was created using automated SQL and R code that extracted and processed patient clinical and surgical data across 37 million clinical encounters from the EHRs. A total of 194 clinical features including patient demographics (e.g., age, sex, race), smoking status, medications, comorbidities, procedure information, and proxies for surgical complexity were constructed and aggregated. A cohort of 66,370 patients that had undergone 99,755 invasive procedural encounters between January 1, 2014, and January 31, 2017, was studied further for the purpose of predicting postoperative complications. The average complication and 30-day postoperative mortality rates of this cohort were 16.0% and 0.51%, respectively. Least absolute shrinkage and selection operator (lasso) penalized logistic regression, random forest models, and extreme gradient boosted decision trees were trained on this surgical cohort with cross-validation on 14 specific postoperative outcome groupings. Resulting models had area under the receiver operator characteristic curve (AUC) values ranging between 0.747 and 0.924, calculated on an out-of-sample test set from the last 5 months of data. Lasso penalized regression was identified as a high-performing model, providing clinically interpretable actionable insights. Highest and lowest performing lasso models predicted postoperative shock and genitourinary outcomes with AUCs of 0.924 (95% CI: 0.901, 0.946) and 0.780 (95% CI: 0.752, 0.810), respectively. A calculator requiring input of 9 data fields was created to produce a risk assessment for the 14 groupings of postoperative outcomes. A high-risk threshold (15% risk of any complication) was determined to identify high-risk surgical patients. The model sensitivity was 76%, with a specificity of 76%. Compared to heuristics that identify high-risk patients developed by clinical experts and the ACS NSQIP calculator, this tool performed superiorly, providing an improved approach for clinicians to estimate postoperative risk for patients. Limitations of this study include the missingness of data that were removed for analysis.

CONCLUSIONS

Extracting and curating a large, local institution's EHR data for machine learning purposes resulted in models with strong predictive performance. These models can be used in clinical settings as decision support tools for identification of high-risk patients as well as patient evaluation and care management. Further work is necessary to evaluate the impact of the Pythia risk calculator within the clinical workflow on postoperative outcomes and to optimize this data flow for future machine learning efforts.

Evaluating Mastectomy Skin Flap Necrosis in the Extended Breast Reconstruction Risk Assessment Score for 1-Year Prediction of Prosthetic Reconstruction Outcomes

BACKGROUND

Rates of mastectomy for breast cancer treatment and immediate reconstruction continue to rise. With increasing scrutiny on outcomes and patient satisfaction, there is an impetus for providers to be more deliberate in appropriate patient selection for breast reconstruction. The Breast Reconstruction Risk Assessment (BRA) Score was developed for prediction of complications after primary prosthetic breast reconstruction, focusing on calculating risk estimations for a variety of complications based on individual patient demographic and perioperative characteristics. In this study, we evaluated mastectomy skin flap necrosis (MSFN) as a function of patient characteristics to validate the BRA Score.

STUDY DESIGN

We examined our prospective intra-institutional database of prosthetic breast reconstructions from 2004 to 2015. The end point of interest was 1-year occurrence of MSFN after stage I tissue expander placement.

RESULTS

Nine hundred and three patients were included; 50% underwent bilateral reconstruction. Median follow-up was 23 months. Mean 1-year complication rates were as follows: MSFN 12.4%, seroma 3.0%, infection 6.9%, dehiscence/exposure 7.1%, and explantation 13.2%. Statistically significantly higher rates of MSFN were found in older patients, smokers, patients with postoperative infections, patients with hypertension, and patients who used aspirin. Neoadjuvant or adjuvant chemotherapy and radiation, diabetes, and seroma formation did not have a statistically significant impact on necrosis rates.

CONCLUSIONS

The BRA Score was expanded to estimate complication risk after tissue expander placement up to 1 year postoperatively. The risk of MSFN as calculated by the BRA Score: Extended Length is consistent with published studies demonstrating increased risk with specific comorbidities, and further validates expansion of the BRA score risk calculator.

Predicting complications of major head and neck oncological surgery: an evaluation of the ACS NSQIP surgical risk calculator

Background

The American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) universal surgical risk calculator is an online tool intended to improve the informed consent process and surgical decision-making. The risk calculator uses a database of information from 585 hospitals to predict a patient’s risk of developing specific postoperative outcomes.

Methods

Patient records at a major Canadian tertiary care referral center between July 2015 and March 2017 were reviewed for surgical cases including one of six major head and neck oncologic surgeries: total thyroidectomy, total laryngectomy, hemiglossectomy, partial glossectomy, laryngopharyngectomy, and composite resection. Preoperative information for 107 patients was entered into the risk calculator and compared to observed postoperative outcomes. Statistical analysis of the risk calculator was completed for the entire study population, for stratification by procedure, and by utilization of microvascular reconstruction. Accuracy was assessed using the ratio of predicted to observed outcomes, Receiver Operating Characteristics (ROC), Brier score, and the Wilcoxon signed–ranked test.

Results

The risk calculator accurately predicted the incidences for 11 of 12 outcomes for patients that did not undergo free flap reconstruction (NFF group), but was less accurate for patients that underwent free flap reconstruction (FF group). Length of stay (LOS) analysis showed similar results, with predicted and observed LOS statistically different in the overall population and FF group analyses (p = 0.001 for both), but not for the NFF group analysis (p = 0.764). All outcomes in the NFF group, when analyzed for calibration, met the threshold value (Brier scores < 0.09). Risk predictions for 8 of 12, and 10 of 12 outcomes were adequately calibrated in the FF group and the overall study population, respectively. Analyses by procedure were excellent, with the risk calculator showing adequate calibration for 7 of 8 procedural categories and adequate discrimination for all calculable categories (6 of 6).

Conclusion

The NSQIP-RC demonstrated efficacy for predicting postoperative complications in head and neck oncology surgeries that do not require microvascular reconstruction. The predictive value of the metric can be improved by inclusion of several factors important for risk stratification in head and neck oncology.

Acute cholecystitis: comparing clinical outcomes with TG13 severity and intended laparoscopic versus open cholecystectomy in difficult operative cases

INTRODUCTION

The revised Tokyo Guidelines include criteria for determining the severity of acute cholecystitis with treatment algorithms based on severity. The aim of this study was to investigate the relationship of the revised Tokyo Guidelines severity grade to clinical outcomes of cholecystectomy for acute cholecystitis.

METHODS

We identified 66 patients with acute cholecystitis from a prior study of difficult cholecystectomy cases. We examined the relationship between severity grade and multiple variables related to perioperative and postoperative outcomes.

RESULTS

A more severe revised Tokyo Guidelines grade was associated with a higher number of complications (p = 0.03) and a higher severity of complications (p = 0.01). Severity grade did not predict operative time, estimated blood loss, intensive care unit admission or length of stay. Compared to planned open cholecystectomy, intended laparoscopic cholecystectomy was associated with significantly fewer total and Clavien-Dindo grade 3 complications, fewer intensive care unit admissions, and shorter length of stay (p values range from 0.03 to < 0.0001).

CONCLUSION

In technically difficult operations for acute cholecystitis, the revised Tokyo guidelines severity grade correlates with the number and severity of complications. However, intended performance of laparoscopic cholecystectomy rather than open cholecystectomy in difficult operations predicts broader beneficial outcomes than severity grade.

American College of Surgeons NSQIP Risk Calculator Accuracy for Emergent and Elective Colorectal Operations

BACKGROUND

The American College of Surgeons NSQIP has developed a risk calculator (RC) to assist patients and surgeons with difficult decisions. The aim of this analysis was to determine the accuracy of the RC in patients undergoing elective and emergent colorectal operations.

STUDY DESIGN

From January 2013 through December 2015, seventy-five patients undergoing emergent colorectal operations were paired by date with 75 patients having elective colorectal operations. Patient data were entered into the RC. Actual postoperative outcomes, derived from NSQIP data, were compared with those predicted by the RC.

RESULTS

Emergent and elective patients differed (p < 0.05) with respect to age, functional status, American Society of Anesthesiologists class, steroid use, wound class, COPD, and chronic renal insufficiency. The RC accurately predicted outcomes in elective patients. Outcomes were significantly worse (p < 0.05) after the emergent operations. In emergent cases, the RC underestimated serious complications and length of stay and overestimated discharge to a skilled nursing facility (all p < 0.05).

CONCLUSIONS

The American College of Surgeons NSQIP RC accurately predicts outcomes for elective colorectal operations. Predicted and actual outcomes are significantly better in patients undergoing elective colon operations compared with those undergoing emergent procedures. The RC should be used with caution in emergent cases, as it has the potential to underestimate serious complications and length of stay, and overestimate discharge to skilled nursing facility. Refinement of the tool to include procedure complexity and diagnosis terms might improve its accuracy in emergent cases.

Predicting Postoperative Complications for Acute Care Surgery Patients Using the ACS NSQIP Surgical Risk Calculator

The American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) risk calculator has been used to assist surgeons in predicting the risk of postoperative complications. This study aims to determine if the risk calculator accurately predicts complications in acute care surgical patients undergoing laparotomy. A retrospective review was performed on all patients on the acute care surgery service at a tertiary hospital who underwent laparotomy between 2011 and 2012. The preoperative risk factors were used to calculate the estimated risks of postoperative complications in both the original ACS NSQIP calculator and updated calculator (June 2016). The predicted rate of complications was then compared with the actual rate of complications. Ninety-five patients were included. Both risk calculators accurately predicted the risk of pneumonia, cardiac complications, urinary tract infections, venous thromboembolism, renal failure, unplanned returns to operating room, discharge to nursing facility, and mortality. Both calculators underestimated serious complications (26% vs 39%), overall complications (32.4% vs 45.3%), surgical site infections (9.3% vs 20%), and length of stay (9.7 days versus 13.1 days). When patients with prolonged hospitalization were excluded, the updated calculator accurately predicted length of stay. The ACS NSQIP risk calculator underestimates the overall risk of complications, surgical infections, and length of stay. The updated calculator accurately predicts length of stay for patients <30 days. The acute care surgical population represents a high-risk population with an increased rate of complications. This should be taken into account when using the risk calculator to predict postoperative risk in this population.

The Difficult Gallbladder: A Safe Approach to a Dangerous Problem

Laparoscopic cholecystectomy is a common surgical procedure, and remains the gold standard for the management of benign gallbladder and biliary disease. While this procedure can be technically straightforward, it can also represent one of the most challenging operations facing surgeons. This dichotomy of a routine operation performed so commonly that poses such a hidden risk of severe complications, such as bile duct injury, must keep surgeons steadfast in the pursuit of safety. The "difficult gallbladder" requires strict adherence to the Culture of Safety in Cholecystectomy, which promotes safety first and assists surgeons in managing or avoiding difficult operative situations. This review will discuss the management of the difficult gallbladder and propose the use of subtotal fenestrating cholecystectomy as a definitive option during this dangerous situation.