Howard K. Song

Variation in Use of Blood Transfusion in Coronary Artery Bypass Graft Surgery

CONTEXT Perioperative blood transfusions are costly and have safety concerns. As a result, there have been multiple initiatives to reduce transfusion use. However, the degree to which perioperative transfusion rates vary among hospitals is unknown. OBJECTIVE To assess hospital-level variation in use of allogeneic red blood cell (RBC), fresh-frozen plasma, and platelet transfusions in patients undergoing coronary artery bypass graft (CABG) surgery. DESIGN, SETTING, AND PATIENTS An observational cohort of 102,470 patients undergoing primary isolated CABG surgery with cardiopulmonary bypass during calendar year 2008 at 798 sites in the United States, contributing data to the Society of Thoracic Surgeons Adult Cardiac Surgery Database. MAIN OUTCOME MEASURES Perioperative (intraoperative and postoperative) transfusion of RBCs, fresh-frozen plasma, and platelets. RESULTS At hospitals performing at least 100 on-pump CABG operations (82,446 cases at 408 sites), the rates of blood transfusion ranged from 7.8% to 92.8% for RBCs, 0% to 97.5% for fresh-frozen plasma, and 0.4% to 90.4% for platelets. Multivariable analysis including data from all 798 sites (102,470 cases) revealed that after adjustment for patient-level risk factors, hospital transfusion rates varied by geographic location (P = .007), academic status (P = .03), and hospital volume (P < .001). However, these 3 hospital characteristics combined only explained 11.1% of the variation in hospital risk-adjusted RBC usage. Case mix explained 20.1% of the variation between hospitals in RBC usage. CONCLUSION Wide variability occurred in the rates of transfusion of RBCs and other blood products, independent of case mix, among patients undergoing CABG surgery with cardiopulmonary bypass in US hospitals in an adult cardiac surgical database.

2012 Update to The Society of Thoracic Surgeons Guideline on Use of Antiplatelet Drugs in Patients Having Cardiac and Noncardiac Operations

Division of Cardiovascular and Thoracic Surgery, University of Kentucky, Lexington, Kentucky (VAF and SPS); Department of Pharmacy Practice, College of Pharmacy, University of Nebraska Medical Center, Omaha, Nebraska (JHO); Division of Cardiothoracic Surgery, Oregon Health and Science University Medical Center, Portland, Oregon (HKS); State University of New York, Stony Brook School of Medicine, Stony Brook, New York (TR); Department of Cardiothoracic Surgery, University of Colorado Health Sciences Center, Aurora, Colorado (TBR); Department of Anesthesia, St. Michael’s Hospital, University of Toronto, Toronto, Ontario (CDM); Division of Cardiovascular Surgery, Sanger Clinic, Charlotte, North Carolina (CRB); Departments of Anesthesiology, Immunology, and Pathology, Washington University School of Medicine, St. Louis, Missouri (GJD); and The Society of Thoracic Surgeons, Chicago, Illinois (KJ and ERC)

Elevated preoperative hemoglobin A1c level is predictive of adverse events after coronary artery bypass surgery

OBJECTIVE Diabetes mellitus has been associated with an increased risk of adverse outcomes after coronary artery bypass grafting. Hemoglobin A1c is a reliable measure of long-term glucose control. It is unknown whether adequacy of diabetic control, measured by hemoglobin A1c, is a predictor of adverse outcomes after coronary artery bypass grafting. METHODS Of 3555 consecutive patients who underwent primary, elective coronary artery bypass grafting at a single academic center from April 1, 2002, to June 30, 2006, 3089 (86.9%) had preoperative hemoglobin A1c levels obtained and entered prospectively into a computerized database. All patients were treated with a perioperative intravenous insulin protocol. A multivariable logistic regression model was used to determine whether hemoglobin A1c, as a continuous variable, was associated with in-hospital mortality, renal failure, cerebrovascular accident, myocardial infarction, and deep sternal wound infection after coronary artery bypass grafting. Receiver operating characteristic curve analysis identified the hemoglobin A1c value that maximally discriminated outcome dichotomies. RESULTS In-hospital mortality for all patients was 1.0% (31/3089). An elevated hemoglobin A1c level predicted in-hospital mortality after coronary artery bypass grafting (odds ratio 1.40 per unit increase, P = .019). Receiver operating characteristic curve analysis revealed that hemoglobin A1c greater than 8.6% was associated with a 4-fold increase in mortality. For each unit increase in hemoglobin A1c, there was a significantly increased risk of myocardial infarction and deep sternal wound infection. By using receiver operating characteristic value thresholds, renal failure (threshold 6.7, odds ratio 2.1), cerebrovascular accident (threshold 7.6, odds ratio 2.24), and deep sternal wound infection (threshold 7.8, odds ratio 5.29) occurred more commonly in patients with elevated hemoglobin A1c. CONCLUSION Elevated hemoglobin A1c level was strongly associated with adverse events after coronary artery bypass grafting. Preoperative hemoglobin A1c testing may allow for more accurate risk stratification in patients undergoing coronary artery bypass grafting.

Organ allocation in adults with congenital heart disease listed for heart transplant: Impact of ventricular assist devices

BACKGROUND Adults with congenital heart disease (CHD) listed for heart transplantation are rarely supported by ventricular assist devices (VADs). This may be a disadvantage to their priority for organ allocation. We sought to determine the relationship between VAD implantation and successful transplantation among patients listed for heart transplant. METHODS Adults with CHD patients (N = 1,250) were identified from the United Network for Organ Sharing (UNOS) database from 1985 to 2010 and compared to patients without congenital etiology for heart failure (N = 59,606). VAD use at listing, listing status, status upgrades and reasons for upgrade prior to transplant were trended at 5-year intervals and appropriate statistical comparisons were made between groups. RESULTS Since 1985, VAD use prior to transplant has increased significantly in patients without CHD, but not in CHD patients (17% vs 3% in 2006 to 2010, p < 0.0001). CHD patients were more likely to be listed as Status 2, compared to those without (66% vs 40%, p < 0.001 for 2006 to 2010), and less likely to be upgraded to Status 1 after listing (43% vs 55%, p = 0.03). Among those upgraded to Status 1, CHD patients were less likely to have a VAD at transplant than those without (3% vs 18%, p = 0.005). VAD use was more likely to result in death in CHD patients. CONCLUSIONS VAD use is less common in CHD patients than in patients without CHD, both at the time of listing and transplantation. Reduced VAD use appears to contribute to lower listing status and organ allocation. These differences have grown more disparate over time. Separate criteria for organ allocation for CHD patients may be justified.

Improved quality and cost-effectiveness of coronary artery bypass grafting in the United States from 1988 to 2005

OBJECTIVE This study was undertaken to assess the impact of increasing patient complexity and health care cost on coronary artery bypass grafting quality and cost-effectiveness in the United States over an 18-year period. METHODS A retrospective study was carried out utilizing the Nationwide Inpatient Sample to track the characteristics and outcomes of 5,549,700 patients having isolated coronary artery bypass grafting in the United States from 1988 to 2005. Expected mortality, risk-adjusted mortality, and hospital charges were tracked over this period. RESULTS The prevalence of congestive heart failure, pulmonary disease, diabetes, and acute myocardial infarction increased significantly over the study period. Expected mortality increased from 2.57% to 3.66%, reflecting the increasing patient comorbidity burden (P < .0001). Despite this, coronary artery bypass grafting outcomes improved, leading to a decrease in risk-adjusted mortality from 6.20% to 2.12% (P < .0001). Furthermore, when hospital charges were corrected for medical care inflation, hospital charges declined significantly, from

Impact of Image Analysis Methodology on Diagnostic and Surgical Classification of Patients With Thoracic Aortic Aneurysms

26,210 in 1988 to

Impact of Single-Ventricle Physiology on Death After Heart Transplantation in Adults With Congenital Heart Disease

19,196 in 2005 (1988 dollars, P < .0001). CONCLUSIONS Coronary artery bypass grafting surgery is being performed on an increasingly complex, high-risk patient population in the United States. Despite this challenge, risk-adjusted operative mortality has progressively declined. Moreover, hospital charges for coronary artery bypass grafting in relation to other medical care services have been reduced. These findings reflect improved quality and cost-effectiveness of coronary artery bypass grafting in the United States. Ongoing efforts directed at quality improvement should address the risks associated with comorbidities that increasingly accompany the diagnosis of coronary artery disease in patients having coronary artery bypass grafting.

Mechanical Circulatory Support Pathways That Maximize Post-Heart Transplant Survival

BACKGROUND For patients with thoracic aortic aneurysms (TAA), aortic size on imaging is widely used to guide clinical decision making. This study examined the impact of methodological variance on aortic quantification. METHODS We studied enrollees in the National Registry of Genetically Triggered Thoracic Aortic Aneurysms and Cardiovascular Conditions. Aortic size on computed tomography was quantified by 2 linear methods; cross-sectional dimensions in axial (AX) and double oblique (DO) plane. Calculated area was compared to planimetry. Established cutoffs (area/height>10 cm2/m, diameter≥5 cm) for prophylactic TAA repair were used to compare surgical eligibility by each method. RESULTS Fifty subjects were studied. Aortic size differed between AX and DO at all locations (p≤0.001), with magnitude greatest at the sinotubular junction (4.8±1.1 vs 4.0±1.0 cm, p<0.001). The difference between AX and DO correlated with aortic angular displacement (r=0.37, p<0.01), which was threefold larger at the sinotubular junction (37±12 degrees) than the ascending aorta (12±5 degrees; p<0.001). At all locations, aortic area calculated using DO yielded smaller differences with planimetry than AX (p<0.05). DO and planimetry yielded equal prevalence (24%) of subjects eligible for prophylactic TAA repair based on area-height cutoff, whereas AX prevalence was higher (44%; p=0.006). Using a linear cutoff, AX yielded over a twofold greater prevalence of surgically eligible subjects (56%) than did DO (24%; p<0.001). CONCLUSIONS Established linear methods for aortic measurement yield different results that impact surgical eligibility. DO yielded improved agreement with planimetry and differed with AX in proportion to aortic geometric obliquity. Findings support DO measurements for imaging evaluation of subjects with TAA.

The National Registry of Genetically Triggered Thoracic Aortic Aneurysms and Cardiovascular Conditions (GenTAC): results from phase I and scientific opportunities in phase II.

BACKGROUND Prevalence of univentricular (1V) anatomy over time and whether 1V anatomy is associated with early death after heart transplant (HTx) among recipients with adult congenital heart disease (ACHD) is unknown. We investigated changes in case-mix over time, 1V vs biventricular (2V) status, and the effect of 1V anatomy on death after HTx among ACHD recipients. METHODS The Nationwide Inpatient Sample (NIS) was used to identify ACHD HTx recipients in the United States aged 14 years or older from 1993 to 2007, divided into era 1 (1993 to 2000) and era 2 (2001 to 2007). In-hospital death was compared among recipients with 1V and 2V anatomy. Multivariable determinants associated with an increased risk of in-hospital death were sought with logistic regression models. RESULTS From a national estimate of 509 ACHD recipients, 143 were 1V and 366 were 2V. Overall, 1V in-hospital mortality (23%) was higher than for 2V (8%; p<0.001) and remained associated with in-hospital death after adjustment for other factors (odds ratio, 3.9; 95% confidence interval, 1.29 to 11.74; p=0.02). All 1V diagnoses had higher mortality than all 2V diagnoses. Despite minor fluctuations, the proportion of 1V patients did not increase over time (era 1, 36%; era 2, 30%; p=0.46). CONCLUSIONS Overall case-mix of ACHD recipients (1V vs 2V) has not changed over time. Initial 1V anatomy increases post-HTx death among ACHD recipients, whereas 2V patients have mortality rates similar to non-CHD recipients. National and international transplant registries should include specific CHD diagnoses because this factor plays such a large role in determining early outcomes.

Gender Differences in Mortality After Mitral Valve Operation: Evidence for Higher Mortality in Perimenopausal Women

BACKGROUND Heart transplant (HTx) recipients reach transplantation through increasing numbers of support pathways, including transition from one pathway to another. Outcomes of patients successfully bridged with various support pathways are unknown. We sought to identify mechanical circulatory support pathways that maximize survival after HTx. METHODS A supplemented United Network Organ Sharing Dataset tracked status 1 HTx outcomes from 2000 to 2010. Recipients were grouped based on support pathway before HTx, including those transitioning from one pathway to another. Multivariable factors for time-related death were sought using Cox proportional hazard regression models. RESULTS We identified 13,250 status 1 HTx recipients. Initial support pathways were inotropes (n = 7,607), left ventricular assist device (LVAD [n = 4,034]), intraaortic balloon pump (n = 729), biventricular assist device (n = 521), extracorporeal membrane oxygenation (ECMO [n = 316]), and right ventricular assist device (n = 43). Multivariable analysis demonstrated that LVAD use conferred a survival advantage (hazard ratio [HR] 0.71; p < 0.001), whereas all other support pathways, including inotropes (HR 1.1; p = 0.02), right ventricular assist device (HR 1.9; p = 0.01), and ECMO (HR 2.2; p < 0.001) increased the risk of post-HTx death. Support pathway transition (both escalation and reduction) occurred in 2,175 patients. Patients who transitioned from either ECMO or biventricular assist device support at listing to LVAD-only support at HTx had improved post-HTx survival that was comparable to patients who had LVAD-only therapy throughout their course (p = 0.74). CONCLUSIONS The LVAD supported HTx recipients have better posttransplant survival than patients after all other mechanical support pathways. Survival after HTx is optimized when ECMO or biventricular assist device support can be transitioned to LVAD-only support. Our findings should aid clinical decision making and inform organ allocation policy development intended to maximize societal benefits of HTx.