Glenn J. Whitman

Effects of Red-Cell Storage Duration on Patients Undergoing Cardiac Surgery

BACKGROUND Some observational studies have reported that transfusion of red-cell units that have been stored for more than 2 to 3 weeks is associated with serious, even fatal, adverse events. Patients undergoing cardiac surgery may be especially vulnerable to the adverse effects of transfusion. METHODS We conducted a randomized trial at multiple sites from 2010 to 2014. Participants 12 years of age or older who were undergoing complex cardiac surgery and were likely to undergo transfusion of red cells were randomly assigned to receive leukocyte-reduced red cells stored for 10 days or less (shorter-term storage group) or for 21 days or more (longer-term storage group) for all intraoperative and postoperative transfusions. The primary outcome was the change in Multiple Organ Dysfunction Score (MODS; range, 0 to 24, with higher scores indicating more severe organ dysfunction) from the preoperative score to the highest composite score through day 7 or the time of death or discharge. RESULTS The median storage time of red-cell units provided to the 1098 participants who received red-cell transfusion was 7 days in the shorter-term storage group and 28 days in the longer-term storage group. The mean change in MODS was an increase of 8.5 and 8.7 points, respectively (95% confidence interval for the difference, -0.6 to 0.3; P=0.44). The 7-day mortality was 2.8% in the shorter-term storage group and 2.0% in the longer-term storage group (P=0.43); 28-day mortality was 4.4% and 5.3%, respectively (P=0.57). Adverse events did not differ significantly between groups except that hyperbilirubinemia was more common in the longer-term storage group. CONCLUSIONS The duration of red-cell storage was not associated with significant differences in the change in MODS. We did not find that the transfusion of red cells stored for 10 days or less was superior to the transfusion of red cells stored for 21 days or more among patients 12 years of age or older who were undergoing complex cardiac surgery. (Funded by the National Heart, Lung, and Blood Institute; RECESS ClinicalTrials.gov number, NCT00991341.).

Lung Injury and Acute Respiratory Distress Syndrome After Cardiac Surgery

As many as 20% of patients undergoing cardiac surgery will have acute respiratory distress syndrome during the perioperative period, with a mortality as high as 80%. If patients at risk can be identified, preventative measures can be taken and may improve outcomes. Care for patients with acute respiratory distress syndrome is supportive, with low tidal volume ventilation being the mainstay of therapy. Careful fluid management, minimization of blood product transfusion, appropriate nutrition, and early physical rehabilitation may improve outcomes. In cases of refractory hypoxemia, rescue therapies such as recruitment maneuvers, high-frequency oscillatory ventilation, and extracorporeal membrane oxygenation may preserve life.

Blood transfusions in cardiac surgery: Indications, risks, and conservation strategies

Although red blood cell (RBC) transfusions are frequently used in cardiac operations, an increasing amount of data has demonstrated deleterious consequences. Consequently, the appropriate use of this limited resource is unclear. In this review, we discuss the relationship between anemia and the outcomes of cardiac surgical procedures, the risks associated with RBC transfusion, and the impact of blood transfusions on mortality and morbidity after cardiac operations. The review concludes with a discussion of randomized trials comparing restrictive versus liberal transfusion strategies and a consideration of blood conservation techniques.

Nadir Oxygen Delivery on Bypass and Hypotension Increase Acute Kidney Injury Risk After Cardiac Operations.

BACKGROUND Acute kidney injury (AKI) continues to complicate cardiac operations. We sought to determine whether nadir oxygen delivery (DO2) on cardiopulmonary bypass (CPB) was a risk factor for AKI while also accounting for other postoperative factors. METHODS Using propensity scoring, we matched 85 patients who developed AKI after cardiac operations on CPB with 85 control patients who did not. We analyzed the following variables through midnight on postoperative day 1 (POD1): DO2, antibiotics, blood products and vasopressors (intraoperatively and postoperatively), and hemodynamic variables. RESULTS Univariable analysis revealed AKI patients had lower nadir DO2 on CPB (208 vs 230 mL O2/min/m(2) body surface area, p = 0.03), lower intensive care unit admission blood pressure gradient across the kidney (mean arterial pressure minus central venous pressure; 60 vs 68 mm Hg; p < 0.001), a greater proportion of patients with mean arterial pressure of less than 60 mm Hg for more than 15 minutes in the postoperative period (70% vs 42%, p < 0.001), a greater chance of having a cardiac index of less than 2.2 (74% vs 49%, p = 0.02), and greater total vasopressor use through the end of POD1 (5.2 vs 2.3 mg, p = 0.002). On multivariable analysis, predictors of AKI were a DO2 on CPB of less than 225 mL O2/min/m(2) (odds ratio, 2.46; 95% confidence interval, 1.21 to 5.03; p = 0.01) and postoperative mean arterial pressure of less than 60 mm Hg for more than 15 minutes (odds ratio, 3.96; 95% confidence interval, 1.92 to 8.20; p < 0.001). An average postoperative pressor dose greater than 0.03 μg/kg/min did not reach significance (odds ratio, 1.98; 95% confidence interval, 0.95 to 4.11; p = 0.07). CONCLUSIONS Postoperative hypotension on POD0 or POD1 and low DO2 on CPB both independently increase the AKI risk in cardiac surgical patients.

Trends in repair of intact and ruptured descending thoracic aortic aneurysms in the United States: A population-based analysis

BACKGROUND To evaluate trends and outcomes of descending thoracic aortic aneurysm (DTAA) repair in the United States. METHODS Adults undergoing DTAA repair between 1998 and 2008 were identified in the Nationwide Inpatient Sample. To limit confounding, patients with connective tissue disorders, aortic dissection, or thoracoabdominal aneurysms were excluded. Stratification was based on intact versus ruptured DTAA and open versus endovascular approach. Standardized annual rates of repair were calculated based on US Census Bureau population estimates. Logistic regression analysis incorporating multiple patient, operative, and hospital variables was used for risk adjustment. RESULTS A total of 20,568 DTAA patients (intact, 17,780; ruptured, 2788) underwent repair (open, 15,265; endovascular, 5303). Patients undergoing repair in the more recent era had higher comorbidity burdens than those undergoing repair in the earlier era. Despite this, annual rates of repair for both intact and ruptured DTAAs increased significantly during the study period (intact, 2.2-10.6 per 1 million; ruptured, 0.8-1.3 per 1 million; P < .05), primarily because of increases in rates of endovascular repair in recent years. Operative mortality decreased from 10.3% to 3.1% for repairs of intact DTAAs (P < .001) and from 52.6% to 23.4% for ruptured DTAAs (P = .002). Endovascular repair was associated with reduced risk-adjusted mortality for both intact (odds ratio, 0.31; P < .001) and ruptured (odds ratio, 0.41; P = .001) DTAAs. CONCLUSIONS Although patients undergoing DTAA repair in the modern era have a higher comorbidity burden, rates of repair have increased and operative mortality has decreased, in part because of the increasing adoption of endovascular approaches.

Right ventricular afterload sensitivity dramatically increases after left ventricular assist device implantation: A multi-center hemodynamic analysis

BACKGROUND Right ventricular (RV) failure is a source of morbidity and mortality after left ventricular assist device (LVAD) implantation. In this study we sought to define hemodynamic changes in afterload and RV adaptation to afterload both early after implantation and with prolonged LVAD support. METHODS We reviewed right heart catheterization (RHC) data from participants who underwent continuous-flow LVAD implantation at our institutions (n = 244), excluding those on inotropic or vasopressor agents, pulmonary vasodilators or additional mechanical support at any RHC assessment. Hemodynamic data were assessed at 5 time intervals: (1) pre-LVAD (within 6 months); (2) early post-LVAD (0 to 6 months); (3) 7 to 12 months; (4) 13 to 18 months; and (5) very late post-LVAD (18 to 36 months). RESULTS Sixty participants met the inclusion criteria. All measures of right ventricular load (effective arterial elastance, pulmonary vascular compliance and pulmonary vascular resistance) improved between the pre- and early post-LVAD time periods. Despite decreasing load and pulmonary artery wedge pressure (PAWP), RAP remained unchanged and the RAP:PAWP ratio worsened early post-LVAD (0.44 [0.38, 0.63] vs 0.77 [0.59, 1.0], p < 0.001), suggesting a worsening of RV adaptation to load. With continued LVAD support, both RV load and RAP:PAWP decreased in a steep, linear and dependent manner. CONCLUSIONS Despite reducing RV load, LVAD implantation leads to worsened RV adaptation. With continued LVAD support, both RV afterload and RV adaptation improve, and their relationship remains constant over time post-LVAD. These findings suggest the RV afterload sensitivity increases after LVAD implantation, which has major clinical implications for patients struggling with RV failure.

Reoperative Sternotomy Is Associated With Increased Mortality After Heart Transplantation

BACKGROUND Although several studies have examined factors affecting survival after orthotopic heart transplantation (OHT), few have evaluated the impact of reoperative sternotomy. We undertook this study to examine the incidence and impact of repeat sternotomies on OHT outcomes. METHODS We conducted a retrospective review of all adult OHT from 2 institutions. Primary stratification was by the number of prior sternotomies. The primary outcome was survival. Secondary outcomes included blood product utilization and commonly encountered postoperative complications. Multivariable Cox proportional hazards regression models examined mortality while linear regression models examined blood utilization. RESULTS From January 1995 to October 2011, 631 OHT were performed. Of these, 25 (4.0%) were redo OHT and 182 (28.8%) were bridged to transplant with a ventricular assist device; 356 (56.4%) had undergone at least 1 prior sternotomy. On unadjusted analysis, reoperative sternotomy was associated with decreased 90-day (98.5% vs 90.2%, p<0.001), 1-year (93.1% vs 79.6%, p<0.001), and 5-year (80.4% vs 70.1%, p=0.002) survival. This difference persisted on multivariable analysis at 90 days (hazard ratio [HR] 2.99, p=0.01), 1 year (HR 2.98, p=0.002), and 5 years (HR 1.62, p=0.049). The impact of an increasing number of prior sternotomies was negligible. On multivariable analysis, an increasing number of prior sternotomies was associated with increased intraoperative blood product utilization. Increasing blood utilization was associated with decreased 90-day, 1-year, and 5-year survival. CONCLUSIONS Reoperative sternotomy is associated with increased mortality and blood utilization after OHT. Patients with more than 1 prior sternotomy do not experience additional increased mortality. Carefully selected patients with multiple prior sternotomies have decreased but acceptable outcomes.

Intense Implementation of a Strict Insulin Infusion Protocol Does Not Guarantee Postoperative Glycemic Control

BACKGROUND The Surgical Care Improvement Project (SCIP) has benchmarked 6:00 AM blood sugars on postoperative days (PODs) 1 and 2 at <200 mg/dL as an indicator of overall glycemic control (GC) in postoperative cardiac surgery patients. However, even in demonstration hospitals that publicly report for incentive payments, only 10% are compliant with this benchmark. The objectives of this study were to validate that the SCIP indicator correlates with overall GC, and relate the intensity of implementation of an insulin infusion protocol (IIP) (goal, blood sugar 100 to 140 mg/dL) to effective GC. STUDY DESIGN All postoperative cardiac surgery patients for 12 consecutive months on the IIP were divided into 2 groups: group 1 included patients who were SCIP compliant (n = 98), and group 2 were patients who were not SCIP compliant (n = 10). For each patient, we determined average blood sugar, duration of hyperglycemia (percent of time with blood sugar >200mg/dL), and intensity of implementation of the IIP, defined as (number of blood sugar checks/hours on IIP), with 0.5 = minimum intensity of implementation dictated by the IIP, ie, an insulin adjustment every 2 hours. RESULTS The average blood sugar for each of the 110 patients was no different than the SCIP 6:00 AM blood sugar: 146 versus 154 mg/dL, p = 0.18. SCIP noncompliance correlated with more intense implementation of the IIP, 0.72 ± 0.03 versus 0.83 ± 0.06 blood sugar checks/hour. CONCLUSIONS The SCIP 6:00 AM blood sugar metric does correlate with average blood sugar on POD 1. Compliance with SCIP 6:00 AM blood sugar measurement is a valid surrogate for GC, though duration of hyperglycemia was still 14% in the compliant group. Use of an IIP does not guarantee GC, despite increased intensity of its application. Even intense use of an IIP may be ineffective when it fails to account for patient risk factors for hyperglycemia.

MELD-XI Score Predicts Early Mortality in Patients After Heart Transplantation

BACKGROUND The aim of this study was to determine the utility of the Model for End-Stage Liver Disease Excluding INR (MELD-XI) in predicting early outcomes (30 days and 1 year) and late outcomes (5 years) in patients after orthotopic heart transplantation (OHT). METHODS The United Network for Organ Sharing database was queried for all adult patients (aged ≥ 18 years) undergoing OHT from 2000 to 2012. A MELD-XI was calculated and the population stratified into score quartiles. Early and late survivals were compared among the MELD-XI cohorts. Multivariable Cox proportional hazards models were constructed to determine the capacity of MELD-XI (when modeled both as a categoric and a continuous variable) to predict 30-day, 1-year, and 5-year mortality. Conditional models were also designed to determine the effect of early mortality on long-term survival. RESULTS A total of 22,597 patients were included for analysis. The MELD-XI cutoff scores were established as follows: low (≤ 10.5), low-intermediate (10.6 to 12.6), intermediate-high (12.7 to 16.4), and high (>16.4). The high MELD-XI cohort experienced statistically worse 30-day, 1-year, and 5-year unconditional survivals when compared with patients with low scores (p < 0.001). Similarly, a high MELD-XI score was also predictive of early and late mortality (p < 0.001) after risk adjustment. There was, however, no difference in 5-year survival between the high score and low score cohorts after accounting for 1-year deaths. Subanalysis of patients bridged to transplant with a continuous-flow left ventricular assist device demonstrated similar findings. CONCLUSIONS This is the first known study to examine the relationship between a high MELD-XI score and outcomes in patients after OHT. Patients with hepatic or renal dysfunction before OHT should be closely monitored and aggressively optimized as early mortality appears to drive long-term outcomes.

A Risk Score to Predict Acute Renal Failure in Adult Patients After Lung Transplantation

BACKGROUND Despite the significant morbidity associated with renal failure after lung transplantation (LTx), no predictive models currently exist. Accordingly, the purpose of this study was to develop a preoperative risk score based on recipient-, donor-, and transplant-specific characteristics to predict postoperative acute renal failure in candidates for transplantation. METHODS The United Network of Organ Sharing (UNOS) database was queried for adult patients (≥ 18 years of age) undergoing LTx between 2005 and 2012. The population was randomly divided into derivation (80%) and validation (20%) cohorts. The primary outcome of interest was new-onset renal failure. Variables predictive of acute renal failure (exploratory p value < 0.2) within the derivation cohort were incorporated into a multivariable logistic regression model. Odds ratios were used to assign values to the independent predictors of postoperative renal failure to construct the risk stratification score (RSS). RESULTS During the study period, 10,963 patients underwent lung transplantation, and the incidence of renal failure was 5.5% (598 patients). Baseline recipient-, donor-, and transplant-related factors were similar between the cohorts. Eighteen covariates were included in the multivariable model, and 10 were assigned values based on their relative odds ratios (ORs). Scores were stratified into 3 groups, with an observed rate of acute renal failure of 3.1%, 5.3%, and 15.6% in the low-, moderate-, and high-risk groups, respectively. The incidence of renal failure was found to be significantly increased in the highest risk group (p < 0.001). Furthermore, the risk models predicted rates of renal failure highly correlated with actual rates observed in the population (r = 0.86). CONCLUSIONS We introduce a novel and simple RSS that is highly predictive of renal failure after LTx.