Himani Gupta

Development and Validation of a Risk Calculator Predicting Postoperative Respiratory Failure

BACKGROUND Postoperative respiratory failure (PRF) (requiring mechanical ventilation > 48 h after surgery or unplanned intubation within 30 days of surgery) is associated with significant morbidity and mortality. The objective of this study was to identify preoperative factors associated with an increased risk of PRF and subsequently develop and validate a risk calculator. METHODS The American College of Surgeons National Surgical Quality Improvement Program (NSQIP), a multicenter, prospective data set (2007-2008), was used. The 2007 data set (n = 211,410) served as the training set and the 2008 data set (n = 257,385) as the validation set. RESULTS In the training set, 6,531 patients (3.1%) developed PRF. Patients who developed PRF had a significantly higher 30-day mortality (25.62% vs 0.98%, P < .0001). On multivariate logistic regression analysis, five preoperative predictors of PRF were identified: type of surgery, emergency case, dependent functional status, preoperative sepsis, and higher American Society of Anesthesiologists (ASA) class. The risk model based on the training data set was subsequently validated on the validation data set. The model performance was very similar between the training and the validation data sets (c-statistic, 0.894 and 0.897, respectively). The high c-statistics (area under the receiver operating characteristic curve) indicate excellent predictive performance. The risk model was used to develop an interactive risk calculator. CONCLUSIONS Preoperative variables associated with increased risk of PRF include type of surgery, emergency case, dependent functional status, sepsis, and higher ASA class. The validated risk calculator provides a risk estimate of PRF and is anticipated to aid in surgical decision making and informed patient consent.

Development and Validation of a Bariatric Surgery Mortality Risk Calculator

BACKGROUND While the epidemic of obesity continues to plague America, bariatric surgery is underused due to concerns for surgical risk among patients and referring physicians. A risk score estimating postoperative mortality (OS-MRS) exists, however, is limited by consideration of only 12 preoperative variables, failure to separate open and laparoscopic cases, a lack of robust statistical analyses, risk factors not being weighted, and being applicable to only gastric bypass surgery. The objective of this study was to develop a validated risk calculator for 30-day postoperative mortality after bariatric surgery. STUDY DESIGN The National Surgical Quality Improvement Program (NSQIP) dataset (2006 to 2008) was used. Patients undergoing bariatric surgery for morbid obesity (n = 32,889) were divided into training (n = 21,891) and validation (n = 10,998) datasets. Multiple logistic regression analysis was performed on the training dataset. The model fit from the training dataset was maintained and was used to estimate mortality probabilities for all patients in the validation dataset. RESULTS Thirty-day mortality was 0.14%. Seven independent predictors of mortality were identified: peripheral vascular disease, dyspnea, previous percutaneous coronary intervention, age, body mass index, chronic corticosteroid use, and type of bariatric surgery. This risk model was subsequently validated. The model performance was very similar between the training and the validation datasets (c-statistics, 0.80 and 0.82, respectively). The high c-statistics indicate excellent predictive performance. The risk model was used to develop an interactive risk calculator. CONCLUSIONS This risk calculator has excellent predictive ability for mortality after bariatric procedures. It is anticipated that it will aid in surgical decision-making, informed patient consent, and in helping patients and referring physicians to assess the true bariatric surgical risk.

Impact of COPD on Postoperative Outcomes: Results From a National Database

BACKGROUND Although COPD affects large sections of the population, its effects on postoperative outcomes have not been rigorously studied. The objectives of this study were to describe the prevalence of COPD in patients undergoing surgery and to analyze the associations between COPD and postoperative morbidity, mortality, and hospital length of stay. METHODS Patients with COPD who underwent surgery were identified from the National Surgical Quality Improvement Program database (2007-2008). Univariate and multivariate analyses were performed on this multicenter, prospective data set (N = 468,795). RESULTS COPD was present in 22,576 patients (4.82%). These patients were more likely to be older, men, white, smokers, and taking corticosteroids and had a lower BMI (P < .0001 for each). Median length of stay was 4 days for patients with COPD vs 1 day in those without COPD (P < .0001). Thirty-day morbidity rates were 25.8% and 10.2% for patients with and without COPD, respectively (P < .0001). Thirty-day death rates were 6.7% and 1.4% for patients with and without COPD, respectively (P < .0001). After controlling for > 50 comorbidities through logistic regression modeling, COPD was independently associated with higher postoperative morbidity (OR, 1.35; 95% CI, 1.30-1.40; P < .0001) and mortality (OR, 1.29; 95% CI, 1.19-1.39; P < .0001). Multivariate analyses with each individual postoperative complication as the outcome of interest showed that COPD was associated with increased risk for postoperative pneumonia, respiratory failure, myocardial infarction, cardiac arrest, sepsis, return to the operating room, and renal insufficiency or failure (P < .05 for each). CONCLUSIONS COPD is common among patients undergoing surgery and is associated with increased morbidity, mortality, and length of stay.

OUTCOMES AFTER THYROIDECTOMY AND PARATHYROIDECTOMY

Previous reports on postoperative outcomes following thyroid and parathyroid surgery are limited by relatively small sample size. We report 30‐day outcomes following thyroid and parathyroid surgery and analyze factors affecting length of stay (LOS) and postoperative adverse events (AEs).

Original ResearchCOPDImpact of COPD on Postoperative Outcomes: Results From a National Database

BACKGROUND Although COPD affects large sections of the population, its effects on postoperative outcomes have not been rigorously studied. The objectives of this study were to describe the prevalence of COPD in patients undergoing surgery and to analyze the associations between COPD and postoperative morbidity, mortality, and hospital length of stay. METHODS Patients with COPD who underwent surgery were identified from the National Surgical Quality Improvement Program database (2007-2008). Univariate and multivariate analyses were performed on this multicenter, prospective data set (N = 468,795). RESULTS COPD was present in 22,576 patients (4.82%). These patients were more likely to be older, men, white, smokers, and taking corticosteroids and had a lower BMI (P < .0001 for each). Median length of stay was 4 days for patients with COPD vs 1 day in those without COPD (P < .0001). Thirty-day morbidity rates were 25.8% and 10.2% for patients with and without COPD, respectively (P < .0001). Thirty-day death rates were 6.7% and 1.4% for patients with and without COPD, respectively (P < .0001). After controlling for > 50 comorbidities through logistic regression modeling, COPD was independently associated with higher postoperative morbidity (OR, 1.35; 95% CI, 1.30-1.40; P < .0001) and mortality (OR, 1.29; 95% CI, 1.19-1.39; P < .0001). Multivariate analyses with each individual postoperative complication as the outcome of interest showed that COPD was associated with increased risk for postoperative pneumonia, respiratory failure, myocardial infarction, cardiac arrest, sepsis, return to the operating room, and renal insufficiency or failure (P < .05 for each). CONCLUSIONS COPD is common among patients undergoing surgery and is associated with increased morbidity, mortality, and length of stay.

Development and validation of a risk calculator for prediction of mortality after infrainguinal bypass surgery.

OBJECTIVE For peripheral arterial disease, infrainguinal bypass grafting (BPG) carries a higher perioperative risk compared with peripheral endovascular procedures. The choice between the open and endovascular therapies is to an extent dependent on the expected periprocedural risk associated with each. Tools for estimating the periprocedural risk in patients undergoing BPG have not been reported in the literature. The objective of this study was to develop and validate a calculator to estimate the risk of perioperative mortality ≤30 days of elective BPG. METHODS We identified 9556 patients (63.9% men) who underwent elective BPG from the 2007 to 2009 National Surgical Quality Improvement Program data sets. Multivariable logistic regression analysis was performed to identify risk factors associated with 30-day perioperative mortality. Bootstrapping was used for internal validation. The risk factors were subsequently used to develop a risk calculator. RESULTS Patients had a median age of 68 years. The 30-day mortality rate was 1.8% (n = 170). Multivariable logistic regression analysis identified seven preoperative predictors of 30-day mortality: increasing age, systemic inflammatory response syndrome, chronic corticosteroid use, chronic obstructive pulmonary disease, dependent functional status, dialysis dependence, and lower extremity rest pain. Bootstrapping was used for internal validation. The model demonstrated excellent discrimination (C statistic, 0.81; bias-corrected C statistic, 0.81) and calibration. The validated risk model was used to develop an interactive risk calculator using the logistic regression equation. CONCLUSIONS The validated risk calculator has excellent predictive ability for 30-day mortality in a patient after an elective BPG. It is anticipated to aid in surgical decision making, informed patient consent, preoperative optimization, and consequently, risk reduction.

Postoperative respiratory failure after thyroid and parathyroid surgery: Analysis of national surgical quality improvement program†‡

The risk–benefit analysis of any operation is influenced by its perioperative complications. Our objective was to examine the relationship between preoperative clinical characteristics and postoperative respiratory failure (PRF: mechanical ventilation for >48 hours after surgery or reintubation) within 30 days of thyroid and parathyroid surgeries.

Hypertensive Emergency in Aortic Dissection and Thoracic Aortic Aneurysm—A Review of Management

Over the last few decades, treatment for aortic dissection and thoracic aortic aneurysms has evolved significantly with improvement in outcomes. Treatment paradigms include medical, endovascular and surgical options. As aortic dissection presents as a hypertensive emergency, diligent control of BP is of utmost importance in order to reduce the progression of dissection with possible aortic branch malperfusion. Treatment should begin on arrival to the emergency department and continues in the intensive care unit, endovascular suite or the operating room. Novel antihypertensive medications with improved pharmacological profile and improved surgical techniques, have improved the prognosis of patients with aortic aneurysm and/or aortic dissection. Nevertheless, morbidity and mortality remain high and hypertensive emergency poses a significant challenge in aortic dissection and thoracic aortic aneurysms.

Outcomes of Aortic Surgery for Abdominal Aortic Graft Infections.

Background: Literature on postoperative outcomes following aortic surgery for aortic graft infection (AGI) is limited by relatively small sample sizes, resulting in lack of national benchmarks for quality of care. We report in-hospital outcomes following abdominal aortic surgery for AGI and identify factors associated with postoperative complications using the Nationwide Inpatient Sample (NIS) database. Methods: Patients who underwent aortic graft resection for AGI were identified from the 2002 to 2008 NIS database, a multicenter database capturing 20% of all US admissions. Multivariable logistic regression analyses were performed. Results: Among 394 patients (men: 73.4%) who underwent abdominal aortic surgery for AGI, 53% of the admissions were emergent/urgent. A significant trend for decreasing number of abdominal aortic surgery for AGIs per year was observed (Pearson r correlation: −.96; P = .0006). Over the same time span, a significant correlation was also seen with decrease in open and increase in endovascular aortic aneurysm repairs in the NIS database. In-hospital rates of overall postoperative morbidity and mortality were 68.3% and 19.8%, respectively. In-hospital rates of postoperative respiratory failure, renal failure, and cardiac arrest were 35.5%, 14.2%, and 8.9%, respectively. Median length of stay was 26 days, with median hospital charges being US

Outcomes After Use of Aortouniiliac Endoprosthesis Versus Modular or Unibody Bifurcated Endoprostheses for Endovascular Repair of Ruptured Abdominal Aortic Aneurysms

184 162. On multivariable analysis, increase in age per year (odds ratio [OR] 1.07; 95% confidence interval [CI]: 1.03-1.12) was independently associated with postoperative morbidity, while higher hospital volume for this procedure was protective (OR: 0.71; 95% CI: 0.56-0.89). No preoperative factors were independently associated with postoperative mortality. Conclusion: Incidence of abdominal aortic surgery for AGI has progressively declined over the span of our study in association with decreased open and increased endovascular aortic aneurysm repairs. Aortic surgery for AGI is associated with very high morbidity and mortality rates along with prolonged lengths of stay and elevated hospital charges. The outcomes of operations for AGI are better in younger patients and higher volume hospitals.