Deep Venous Thrombosis and Pulmonary Embolism in Cardiac Surgical Patients

BACKGROUND

Deep venous thrombosis and pulmonary embolism are life-threatening complications after surgery, warranting prophylaxis. However prophylaxis is not uniformly practiced among cardiac surgical patients. This study aimed to characterize the national incidence, mortality, and costs associated with thromboembolism after cardiac surgery.

METHODS

The 2005 to 2015 National Inpatient Sample was used to identify all adult patients undergoing coronary artery bypass grafting or valve surgery. International Classification of Disease codes were used to identify patients with deep venous thrombosis and pulmonary embolism.

RESULTS

Of approximately 3 million patients undergoing cardiac surgery, 1.62% developed deep venous thrombosis and 0.38% pulmonary embolism. Those with deep venous thrombosis and pulmonary embolism were more commonly women (33.2% and 36.2 vs 31.2%, P < .001), older (68.1 and 66.0% vs 65.7 years, P < .001), and had a higher Elixhauser comorbidity index (4.0 and 4.7 vs 3.7, P < .001). Deep venous thrombosis and pulmonary embolism were associated with increased mortality (4.95% and 14.8% vs 2.67%, P < .001). After adjustment for baseline differences, deep venous thrombosis was associated with an incremental increase in cost of $12,308, whereas pulmonary embolism was associated with $13,879 cost increase after cardiac surgery. Pulmonary embolism was an independent predictor of mortality (adjusted odds ratio, 3.39; 95% confidence interval, 2.74-4.18).

CONCLUSIONS

The mortality and financial burden related to thromboembolism in cardiac surgery are significant. Prophylaxis may be indicated in cardiac surgery patients to improve quality of care and reduce healthcare costs. Future controlled randomized trials investigating the benefit of thromboembolism prophylaxis in cardiac surgery are warranted.

National Study of Immediate and Delayed Readmissions After Colostomy Creation

BACKGROUND

Readmissions after colorectal operations adversely impact patient recovery and are associated with about $300 million in additional health care expenditure in the United States alone. The present study aimed to characterize nonelective, short-term readmissions of colorectal surgery patients who underwent colostomy.

METHODS

The Nationwide Readmissions Database was used to identify patients who received a colostomy from 2010 to 2015. Patients were stratified by discharge-to-readmission interval: immediate (within 7 d) and delayed (7-30 d). Nonparametric trend analysis and multivariable regression were performed to identify predictors of immediate and delayed readmission.

RESULTS

Of an estimated 376,693 operations requiring colostomies during the study, in-hospital survival was 92.3%, with higher rates after elective compared with nonelective operations (96.5 versus 90.8%, P < 0.001). Overall, 15.3% patients undergoing elective and nonelective colostomy creation returned to the hospital within 30 d, with 41.6% of these readmissions occurring by the first week of discharge (immediate). Readmission rates and proportion of immediate and delayed groups did not significantly change over the 6-year study period. Nonhome discharge increased the odds of immediate (AOR 1.25, 95% CI 1.17-1.34) and delayed readmission (AOR 1.44, 95% CI 1.35-1.54). Annually, immediate and delayed rehospitalizations after colostomy creation were responsible for $64 and 82 million in excess costs, respectively.

CONCLUSIONS

Colostomy creation is associated with a steady and high rate of rehospitalization. Nonhome discharge, in addition to several patient comorbidities, is associated with higher odds of readmission. Programs aimed at reduction of immediate readmission are warranted.

Acute kidney injury is independently associated with mortality and resource use after emergency general surgery operations

INTRODUCTION

The incidence of severe perioperative renal dysfunction in high-acuity patients has not been well-explored at the national level. The present study aimed to evaluate the trends in the incidence of perioperative acute kidney injury and renal replacement therapy as well as associated mortality among patients undergoing an emergency general surgery operation.

METHODS

This was a retrospective cohort study using the National Inpatient Sample to identify all adult patients (>18 y) without chronic kidney disease who underwent an emergency general surgery procedure from 2008 to 2016. The study cohort was stratified based on presence of acute kidney injury and need for renal replacement therapy postoperatively. A multivariable logistic regression model was developed to predict the odds of mortality and composite morbidity. Nonparametric trend analyses of acute kidney injury and renal replacement therapy incidence and associated mortality were performed.

RESULTS

Of an estimated 5,862,657 patients who underwent an emergency general surgery procedure during the study period, 7.4% patients developed an acute kidney injury and 0.48% patients required renal replacement therapy. Overall, the incidence of acute kidney injury (5.3%-19.4%) and renal replacement therapy (0.43%-0.93%) increased (P < .0001) over the study period. Even without need for renal replacement therapy, acute kidney injury was associated with greater odds of mortality and composite morbidity (adjusted odds ratio 5.2, 95% confidence interval [CI] 5.1-5.3) and mortality (adjusted odds ratio = 2.20, 95% CI 2.3-2.4), as well as greater costs of hospitalization and duration of stay.

CONCLUSION

In this national study, we found that the incidence of acute kidney injury and renal replacement therapy after an emergency general surgery operation has increased. Both acute renal failure and hemodialysis were associated with much greater odds of morbidity and mortality. The apparent increase in the rate of acute kidney injury and renal replacement therapy warrant further investigation of mechanisms for monitoring and limiting the impact of organ malperfusion associated with emergency general surgery operations.

International Normalized Ratio (INR) Is Comparable to MELD in Predicting Mortality after Cholecystectomy

Guidelines suggest targeting a preoperative international normalized ratio (INR) < 1.5. We examined and compared the predictive value of INR relative to the Model for End-Stage Liver Disease (MELD). We reviewed the American College of Surgeons NSQIP from 2005 to 2016 for adult patients undergoing open or laparoscopic cholecystectomy. Patients with a preoperative INR were stratified into groups: ≤1, >1 to ≤1.5, >1.5 to ≤2, and >2. Thirty day postoperative mortality was the primary outcome. Multivariable logistic regressions controlled for baseline differences. Of 58,177 cholecystectomy patients, 15.2 per cent had INR ≤ 1, 80.4 per cent had INR > 1 to ≤1.5, 3.7 per cent had INR > 1.5 to ≤2, and 0.7 per cent had INR > 2. Patients with INR > 2 were older and more likely to have diabetes and hypertension (P < 0.001). Multivariable regression demonstrated a stepwise increase in mortality for INR > 1 to ≤1.5 (odds ratio (OR) = 1.50 [1.10-2.05]), INR > 1.5 to ≤2 (OR = 2.96 [1.97-4.45]), and INR > 2 (OR = 3.21 [1.64-6.31]) relative to INR ≤ 1. C-statistic for INR (0.910) and MELD (0.906) models indicated a similar value in predicting mortality. INR groups also faced an incremental, increased risk of bleeding. Although unable to track preoperative correction of INR, this analysis identifies that INR remains an excellent predictor of postoperative mortality and bleeding after both open and laparoscopic cholecystectomies and is comparable to MELD.

International Normalized Ratio (INR) is Comparable to MELD in Predicting Mortality after Cholecystectomy

Guidelines suggest targeting a preoperative international normalized ratio (INR) < 1.5. We examined and compared the predictive value of INR relative to the Model for End-Stage Liver Disease (MELD). We reviewed the American College of Surgeons NSQIP from 2005 to 2016 for adult patients undergoing open or laparoscopic cholecystectomy. Patients with a preoperative INR were stratified into groups: ≤1, >1 to ≤1.5, >1.5 to ≤2, and >2. Thirty day postoperative mortality was the primary outcome. Multivariable logistic regressions controlled for baseline differences. Of 58,177 cholecystectomy patients, 15.2 per cent had INR ≤ 1,80.4 per cent had INR > 1 to ≤1.5,3.7 per cent had INR > 1.5 to ≤2, and 0.7 per cent had INR > 2. Patients with INR > 2 were older and more likely to have diabetes and hypertension ( P < 0.001). Multivariable regression demonstrated a stepwise increase in mortality for INR > 1 to ≤1.5 (odds ratio (OR) = 1.50 [1.10–2.05]), INR > 1.5 to ≤2 (OR = 2.96 [1.97–4.45]), and INR > 2 (OR = 3.21 [1.64–6.31]) relative to INR ≤ 1. C-statistic for INR (0.910) and MELD (0.906) models indicated a similar value in predicting mortality. INR groups also faced an incremental, increased risk of bleeding. Although unable to track preoperative correction of INR, this analysis identifies that INR remains an excellent predictor of postoperative mortality and bleeding after both open and laparoscopic cholecystectomies and is comparable to MELD.

Understanding lung transplant listing practices: Survival in lung transplant candidates who improve clinically to delisting

BACKGROUND

Occasionally, lung transplant candidates improve to the point where they are removed from the transplant list. We sought to determine the characteristics and outcomes of lung transplant candidates who improved to delisting both before and after implementation of the lung allocation score.

METHODS

Using the United Network for Organ Sharing database, we reviewed all adult patients listed for lung transplant between 1987 and 2012. The last permanent status change was classified into transplanted, improved to delisting (improved), or deteriorated to delisting (deteriorated). Survival time was calculated using the linked date of death from the Social Security Administration. Survival analysis was performed via the Kaplan-Meier method, and adjusted multivariable logistic regressions identified characteristics predicting improvement to delisting.

RESULTS

Of 13,688 candidates, 12,188 (89.0%) were transplanted, 454 (3.3%) improved, and 1,046 (7.6%) deteriorated. The 5-year mortality was greater in improved (hazard ratio = 1.21 [1.07-1.38], P = .002) and deteriorated (hazard ratio = 3.36 [3.11-3.64], P < .001) candidates relative to those transplanted; however, 1-year survival was greater in improved versus transplanted candidates (75.9% vs 67.2%, log rank P < .001). Older, female patients listed for primary pulmonary hypertension and retransplantation were more likely to improve to delisting. The proportion of improved patients varied by hospital quartile volume (P < .001) and the United Network for Organ Sharing geographic region (P < .001). The number of patients improving to delisting decreased after implementation of the lung allocation score.

CONCLUSION

Lung transplant candidates improving to delisting faced less short-term but greater long-term mortality relative to transplanted candidates. Given that the improved population decreased dramatically after implementation of the lung allocation score, redefining patient listing criteria appears to have improved patient appropriateness for transplant.

Complete Impact of Care Fragmentation on Readmissions Following Urgent Abdominal Operations

BACKGROUND

Urgent abdominal operations commonly occurred in low-volume hospitals with high failure-to-rescue rates. Recent studies have demonstrated a survival benefit associated with readmission to the original hospital after operation, presumably due to improved continuity of care. It is unclear if this survival benefit persists in low-volume hospitals. We seek to evaluate differences in mortality between readmission to the original hospital and a higher-volume hospital after urgent abdominal operations.

METHODS

A retrospective cohort study using the National Readmissions Database from 2010 to 2014 was performed. Propensity score-weighted multilevel regression analysis was used to examine the association between readmission destination and mortality after accounting for hospital volume.

RESULTS

A total of 71,551 adult patients who experienced 30-day readmission following urgent abdominal operations were identified, among whom 10,368 (14.5%) were readmitted to a different hospital. Patients with higher baseline comorbidity scores, lower income, less comprehensive insurance coverage, systemic complications, prolonged length of stay, or non-home disposition were more likely to experience readmission to a different hospital. Following stratification by readmission hospital volume and propensity score weighting to adjust for baseline mortality risk differences, readmission to a different hospital is still associated with higher mortality rates than the original hospital.

CONCLUSIONS

The adverse outcomes associated with case fragmentation are present even after adjusting for readmission hospital volume. Patients who received urgent abdominal operations at low-volume hospitals should return to the original hospital for concern of care fragmentation.

Readmissions Following Isolated Coronary Artery Bypass Graft Surgery in the United States (from the Nationwide Readmissions Database 2010 to 2014)

Readmission following cardiac surgery is associated with poor outcomes and increased healthcare expenditure. However, a nationwide understanding of the incidence, cost, causes, and predictors of 30-day readmission following coronary artery bypass grafting is limited. The Nationwide Readmissions Database was used to identify all adult patients who underwent isolated coronary artery bypass grafting (CABG) with no other concomitant surgery between 2010 and 2014. The primary outcome was all-cause readmission within 30 days of discharge after surgery. Risk-adjusted multivariable analyses were used to develop a model of readmission risk. Of 855,836 patients, 95,504 (11.2%) had an emergent 30-day readmission following CABG. The most common causes of readmission were related to respiratory complications (17.1%), infection (13.5%), and heart failure (11.9%). Readmission cost an average of $13,392 per patient, accounting for an estimated annual cost of over $250 million. Independent predictors of 30-day readmission encompassed female gender (odds ratio [OR] 1.27; 95% confidence interval [CI] 1.24 to 1.31), emergent index admission (OR 1.29; 95% CI 1.25 to 1.33), and preoperative co-morbidities, including atrial fibrillation (OR 1.24; 95% CI 1.21 to 1.28), liver disease (OR 1.29; 95% CI 1.17 to 1.41), renal failure (OR 1.38; 95% CI 1.34 to 1.43), among others. CABG performed at a high CABG volume hospital was protective of readmission (OR 0.95; 95% CI 0.91 to 0.99). In conclusion, we characterized using a national sample the incidence, causes, costs, and predictors of 30-day readmission following CABG. Targeting modifiable risk factors for readmission should be a priority to reduce rates of readmission and decrease healthcare expenditure.

Impact of hospital safety-net status on failure to rescue after major cardiac surgery

BACKGROUND

Hospitals with safety-net status have been associated with inferior surgical outcomes and higher costs. The mechanism of this discrepancy, however, is not well understood. We hypothesized that discrepant rates of failure to rescue after complications of routine cardiac surgery would explain the observed inferior outcomes at safety-net hospitals.

METHODS

The National Inpatient Sample was used to identify adult patients who underwent elective coronary artery bypass grafting and isolated or concomitant valve operations between January 2005 and December 2016. Hospitals were stratified into low-, medium-, or high-burden categories based on the proportion of uninsured or Medicaid patients to emulate safety-net status as defined by the Institute of Medicine. Failure to rescue was defined as mortality after occurrence of neurologic, cardiovascular, respiratory, renal, or infectious complications (major and minor complications). Multivariable regression was used to perform risk-adjusted comparisons of the rate of complications, failures to rescue, and resource use for high-burden hospitals versus low-burden and medium-burden hospitals.

RESULTS

Of an estimated 2,012,104 patients undergoing elective major cardiac operations, 2% died, whereas 36% suffered major and minor complications. Safety-net hospitals had higher odds of failure to rescue after major comorbidity (adjusted odds ratio 1.12, 95% confidence interval 1.01-1.23). Occurrence of major and minor complications at safety-net hospitals was associated with increased costs ($2,480 [95% confidence interval $1,178-$3,935]) compared with low-burden hospitals.

CONCLUSION

Safety-net hospitals were associated with higher rates of failure to rescue after occurrence of tamponade, septicemia, and respiratory complications. Implementation of care bundles to tackle cardiovascular, respiratory, and renal complications may affect the discrepancy in incidence of and rescue from complications at safety-net institutions.

Impact of Donor Diabetes on Outcomes of Lung Transplantation in the United States

BACKGROUND

Diabetes mellitus is among several factors considered when assessing the suitability of donated organs for transplantation. Lungs from diabetic donors (LDD) are not contraindicated for use as allografts, despite established evidence of diabetes-mediated parenchymal damage. The present study used a national database to assess the impact of donor diabetes on the longevity of lung transplant recipients.

METHODS

This retrospective study of the United Network for Organ Sharing database analyzed all adult lung transplant recipients from June 2005 through September 2016. Donor and recipient demographics including the presence of diabetes were used to create a multivariable model. The primary outcome was 5-y mortality, with hazard ratios (HRs) assessed using multivariable Cox regression analysis. Survival curves were calculated using the Kaplan-Meier method.

RESULTS

Of the 17,839 lung transplant recipients analyzed, 1203 (6.7%) received LDD. Recipients of LDD were more likely to be female (44.1% versus 40.2%, P < 0.01) and have mismatched race (47.5% versus 42.2%, P < 0.01). Diabetic donors were more likely to have hypertension (74.6% versus 19.0%, P < 0.01). Multivariable analysis revealed LDD to be an independent predictor of mortality at 5 y (HR 1.16 [1.04-1.29], P < 0.01). However, among the subgroup of diabetic recipients, transplantation of LDD showed no independent association with 5-y mortality (HR 0.81 [0.63-1.06], P = 0.12).

CONCLUSIONS

Recipients of LDD had a lower 5-y post lung transplantation survival compared with recipients of lungs from nondiabetic donors. LDD allografts did not influence the survival of diabetic recipients.

Rehospitalization and resource use after inpatient admission for extracorporeal life support in the United States

BACKGROUND

With increasing dissemination and improved survival after extracorporeal life support, also called extracorporeal membrane oxygenation, the decrease in readmissions after hospitalization involving extracorporeal life support is an emerging priority. The present study aimed to identify predictors of early readmission after extracorporeal life support at a national level.

METHODS

This was a retrospective cohort study using the Nationwide Readmissions Database. All patients ≥18 years who underwent extracorporeal life support from 2010 to 2015 were identified. Patients were stratified into the following categories of extracorporeal life support: postcardiotomy, primary cardiogenic shock, cardiopulmonary failure, respiratory failure, transplantation, and miscellaneous. The primary outcome of the study was the rate of 90-day rehospitalization after extracorporeal life support admission. A multivariable logistic regression model was developed to predict the odds of unplanned 90-day readmission. Kaplan-Meier analyses were also performed.

RESULTS

An estimated 18,748 patients received extracorporeal life support with overall mortality of 50.2%. Of the patients who survived hospitalization, 30.2% were discharged to a skilled nursing facility, and 21.1% were readmitted within 90 days after discharge. After adjusting for patient and hospital characteristics, cardiogenic shock was associated with the greatest odds of mortality (adjusted odds ratio 1.6; 95% confidence interval, 1.09-1.46; C-statistic, 0.64). The cohort with respiratory failure had decreased odds of readmission (adjusted odds ratio 0.76; 95% confidence interval, 0.58-0.99). Discharge to skilled nursing facility (adjusted odds ratio 1.64; 95% confidence interval, 1.36-1.97) was independently associated with readmission. Cardiac and respiratory-related readmissions comprised the majority of unplanned 90-day rehospitalizations.

CONCLUSION

In this large analysis of readmissions after extracorporeal life support in adults, 21% of extracorporeal life support survivors were rehospitalized within 90 days of discharge. Disposition to a skilled nursing facility, but not advanced age nor female sex, was associated with readmission.

Association of Autoimmune Connective Tissue Disease and Outcomes in Patients Undergoing Transcatheter Aortic Valve Implantation

Patients with autoimmune connective tissue disease (CTD) are at higher risk for developing aortic valve pathology, but the safety and value of transcatheter aortic valve implantation (TAVI) in this population has not been investigated. This study evaluated mortality, complication, and readmission rates along with length of stay and total costs after TAVI in patients with CTD. We retrospectively reviewed 47,216 patients who underwent TAVI from the National Readmissions Database between January 2011 and September 2015. Patients with systemic lupus erythematosus, scleroderma, rheumatoid arthritis, and other autoimmune CTD comprised the cohort. The primary outcome was mortality at index hospitalization. The 2,557 CTD patients (5.4%) had a higher Elixhauser co-morbidity index (7.1 vs 6.1, p <0.001) than non-CTD patients. CTD and non-CTD patients had similar mortality (2.8 vs 4.1%, p = 0.052), 30-day readmission (19.3 vs 17.0%, p = 0.077), length of stay (8.2 vs 8.3 days, p = 0.615), and total adjusted costs ($57,202 vs $58,309, p = 0.196), respectively. However, CTD patients were more frequently readmitted for postoperative infection (9.4 vs 5.6%, p = 0.042) and septicemia (8.2 vs 4.5%, p = 0.019). After multivariable adjustment, CTD patients faced lower mortality at index hospitalization (odds ratio [OR] 0.56 [0.38 to 0.82], p = 0.003) but were more frequently readmitted for septicemia (OR = 1.95 [1.10 to 3.45], p = 0.023) and postoperative infection (OR = 3.10 [1.01 to 9.52], p = 0.048) relative to non-CTD patients. In conclusion, CTD is not a risk factor for in-hospital mortality but is an independent risk factor for infectious complications post-TAVI.

Trends in Readmission and Costs After Transcatheter Implantation Versus Surgical Aortic Valve Replacement in Patients With Renal Dysfunction

Patients with renal dysfunction are at increased risk for developing aortic valve pathology. In the present era of value-based healthcare delivery, a comparison of transcatheter and surgical aortic valve replacement (SAVR) readmission performance in this population is warranted. All adult patients who underwent transcatheter or SAVR from 2011 to 2014 were identified using the Nationwide Readmissions Database, containing data for nearly 50% of US hospitalizations. Patients were further stratified as chronic kidney disease stage 1 to 5 as well as end-stage renal disease requiring dialysis. Kaplan-Meier, Cox Hazard, and multivariable regression models were generated to identify predictors of readmission and costs. Of the 350,609 isolated aortic valve replacements, 4.7% of patients suffered from chronic kidney disease stages 1 to 5 or end-stage renal disease. Transcatheter aortic valve patients with chronic kidney disease stages 1 to 5/or end-stage renal disease were older (81.9 vs 72.9 years, p <0.0001) with a higher prevalence of heart failure (15.2 vs 4.3%, p = 0.04), and peripheral vascular disease (31.1 vs 22.8%, p <0.0001) compared to their SAVR counterparts. Transcatheter aortic valve replacement in chronic kidney disease stage 1 to 3 patients had a higher rate of readmission due to heart failure and pacemaker placement than SAVR. Transcatheter aortic valve replacement was associated with increased costs compared with SAVR for all renal failure patients. In conclusion, in this national cohort of chronic and end-stage renal disease patients, transcatheter aortic valve implantation was associated with increased mortality, readmissions for chronic kidney disease stages1 to 3, and index hospitalization costs.