Practice makes perfect? Institutional coronary artery bypass case volumes and outcomes.

OBJECTIVES: Older studies of coronary artery bypass grafting (CABG) institutional case volumes and outcomes reported conflicting results. We explored this association in the rapidly changing contemporary practice of American surgeons using the Society of Thoracic Surgeons (STS) Adult Cardiac Surgery Database. METHODS: The 2018-2019 isolated primary CABG experience in the STS Adult Cardiac Surgery Database was analysed (241 902 patients; 1014 hospitals; 2718 surgeons). Generalized Estimating Equations were used to estimate coefficients between CABG institutional case volumes and outcomes. The observed-to-expected ratios based on STS risk models were used to assess risk-adjusted operative mortality (OM), mortality/major morbidity (MM) and deep sternal wound infections (DSWI) as a function of institutional case volumes. RESULTS: The mean (standard deviation) OM, MM and DSWI rates were 2.1% (2.7), 11.1% (9.2) and 0.6% (0.5), respectively. The mean (standard deviation) institutional case volumes per study period was 239 (192); 23% and 9% of institutions performed <100 and >500 cases/study period, respectively. There was a weak negative correlation between expected mortality (R2 -0.0014), OM (R2 -0.0272), MM (R2 -0.1213) and DSWI (R2 -0.003) and institutional case volumes. CONCLUSIONS: CABG outcomes generally improve with increasing institutional case volumes. Given the large number of CABG cases performed nationally, even the documented weak correlation has the potential to appreciably decrease OM, MM and DSWI if cases are performed at higher volume institutions. Studies focusing on additional hospital and surgeon factors are warranted to further define quality improvement opportunities.

Multiarterial Coronary Artery Bypass Grafting Practice Patterns in the United States: Analysis of The Society of Thoracic Surgeons Adult Cardiac Surgery Database.

BACKGROUND: We aimed to elucidate current national multiarterial coronary bypass grafting practice patterns and assess perioperative outcomes. METHODS: Isolated primary nonemergent/nonsalvage coronary artery bypass grafting patients with at least 1 internal thoracic artery and 2 or more grafts in The Society of Thoracic Surgery Adult Cardiac Surgery Database (2018-2019) were divided into 3 cohorts: single-arterial, bilateral internal thoracic artery (BITA), and radial artery multiarterial grafting. Observed-to-expected ratios based on 2017 Society of Thoracic Surgery risk models were derived for 30-day perioperative mortality, composite major morbidity and mortality, and deep sternal wound infections for each grafting group overall and as a function of institutional multiarterial case volumes per study period: low (<10), intermediate (11-30), and high (>30). RESULTS: A total of 281,515 patients (BITA, 15,663 [5.6%]; radial, 23,905 [8.5%]) at 1013 centers showed distinct geographic grafting patterns: BITA and radial multiarterial grafting rates were lowest in the South (4% and 6%, respectively) and highest in the Northeast (9% and 11%, respectively). The median institutional number of BITA and radial cases per study period was 4 and 7, with only 14% and 21% of institutions performing >30 BITA and radial multiarterial cases per study period, respectively. The observed-to-expected mortality for single-arterial bypass grafting was similar to multiarterial: single-arterial, 1.00 (95% CI, 0.98-1.03); BITA, 0.98 (95% CI, 0.84-1.13; P = .711); and radial, 0.96 (95% CI, 0.86-1.07; P = .818). Observed-to-expected mortality and composite major morbidity and mortality were lower at high vs low multiarterial case-volume centers: 0.91 (95% CI, 0.75-1.08) vs 1.30 (95% CI, 0.89-1.79; P = .048) and 1.06 (95% CI, 0.99-1.13) vs 1.51 (95% CI, 1.32-1.71; P < .001), respectively, for BITA, and 0.82 (95% CI, 0.87-1.30) vs 1.67 (95% CI, 1.21-2.21; P < .001) and 0.91 (95% CI, 0.93-1.08) vs 1.42 (95% CI, 1.24-1.61; P < .001), respectively, for radial. CONCLUSIONS: Multiarterial bypass grafting remains underused and limited to select centers. Worse outcomes at low-volume BITA and radial institutions document a case-volume outcomes effect. Additional studies are warranted to improve multiarterial outcomes at low-volume institutions.

ABO Blood Group and Transfusions In the Intraoperative and Postoperative Period After LVAD Implantation.

OBJECTIVES: To assess whether blood group O patients undergoing left ventricular assist device (LVAD) insertion have higher perioperative transfusion requirements, postoperative chest tube output, and postoperative changes in hematocrit. DESIGN: Retrospective review of 116 LVAD patients from August 2015 to May 2018. SETTING: Single-institution, urban academic medical center. PARTICIPANTS: One hundred sixteen LVAD patients analyzed by blood group: group O (n = 49) versus non-O (n = 67). INTERVENTIONS: Transfusions in the combined intraoperative and postoperative period at 7 days and 90 days after LVAD implantation, chest tube output in the first 24 hours, and hematocrit change in the first 48 hours postoperatively. RESULTS: There was no difference between group O and non-O within the univariable analysis for both 7-day and 90-day transfusion rates. Adjusting for covariables, blood type O was not associated with packed red blood cells transfusion after accounting for multiple comparisons (odds ratio 1.33 [1.07-1.66], p = 0.01, where p < 0.005 was considered statistically significant as a Bonferroni correction was performed to control the familywise error rate). Additionally, there was no difference in chest tube output over the first 24 hours (1,129 v 1,057 mL, p = 0.47) or hematocrit change in the first 48 hours postoperatively (3.49 v 4.53%, p = 0.15). CONCLUSION: O blood group is not a significant predictor of transfusion requirements in the combined intraoperative and postoperative period up to 90 days after LVAD implantation.

Improved operative and recovery times with mini-thoracotomy aortic valve replacement.

BACKGROUND: The small incisions of minimally invasive surgery have the proposed benefit of less surgical trauma, less pain, and faster recovery. This study was done to compare minimally invasive techniques for aortic valve replacement, including right anterior mini-thoracotomy and mini-sternotomy, to conventional sternotomy. METHODS: We retrospectively reviewed 503 patients who underwent isolated aortic valve replacement at our institution from 2012 to 2015 using one of three techniques: 1) Mini-thoracotomy, 2) Mini-sternotomy, 3) Conventional sternotomy. Demographics, operative morbidity, mortality, and postoperative complications were compared. RESULTS: Of the 503 cases, 267 (53.1%) were mini-thoracotomy, 120 (23.8%) were mini-sternotomy, and 116 (23.1%) were conventional sternotomy. Mini-thoracotomy patients, compared to mini-sternotomy and conventional sternotomy, had significantly shorter bypass times [82 (IQ 67-113) minutes; vs. 117 (93.5-139.5); vs. 102.5 (85.5-132.5), respectively (p < 0.0001)], a lower incidence of prolonged ventilator support [3.75% vs. 9.17 and 12.9%, respectively (p = 0.0034)], and required significantly shorter ICU and postoperative stays, resulting in an overall shorter hospitalization [6 (IQ 5-9) days; vs. 7 (5-14.5); vs 9 (6-15.5), respectively (p < 0.05)]. Incidence of other postoperative complications were lower in the mini-thoracotomy group compared to mini-sternotomy and conventional sternotomy, without significance. Minimally invasive techniques trended towards better survival [mini-thoracotomy 1.5%, mini-sternotomy 1.67%, and conventional sternotomy 5.17% (p = 0.13)]. CONCLUSIONS: Minimally invasive aortic valve replacement approaches are safe, effective alternatives to conventional sternotomy. The mini-thoracotomy approach showed decreased operative times, decreased lengths of stay, decreased incidence of prolonged ventilator time, and a trend towards lower mortality when compared to mini-sternotomy and conventional sternotomy.

A meta-analysis comparing transaxillary and transfemoral transcatheter aortic valve replacement.

BACKGROUND: While transfemoral (TF) approach is considered as the default access for transcatheter aortic valve replacement (TAVR), the alternative access route of choice remains to be elucidated. Transaxillary (TAx) approach has shown promise as an excellent option. We performed a meta-analysis of the studies comparing the TF and TAx approaches using one type of self-expandable transcatheter valve to avoid device-related bias. METHODS: We searched PubMed/MEDLINE, EMBASE, and the Cochrane Library from inception to December 2018 to identify articles comparing TAx-TAVR and TF-TAVR. The studies included in this meta-analysis contain data related to the use of the CoreValve device. Patients' baseline characteristics, procedural outcomes, and clinical outcomes were extracted from the articles and pooled for analysis. RESULTS: The meta-analysis included five studies comprising 1,414 patients in the TF group and 489 patients in the TAx group. The average EuroScores of the TF and TAx groups were 20.04±13.89 and 22.73±14.73, respectively. The TAx group has higher rates of major comorbidities. No difference was found between the two groups with regard to vascular complications (P=0.71; OR 1.08; 95% CI, 0.71-1.65), aortic regurgitation (P=0.90; OR 1.03; 95% CI, 0.71-1.49), and permanent pacemaker (PPM) implantation (P=0.42; OR 1.12; 95% CI, 0.86-1.46). The TAx group has a lower incidence of acute kidney injury (AKI) (P=0.05; OR 1.63; 95% CI, 1.01-2.62). No difference was observed in 30-day mortality (P=0.32; OR 1.30; 95% CI, 0.78-2.17) or 1-year mortality (P=0.21; OR 0.76; 95% CI, 0.50-1.16). CONCLUSIONS: TAx-TAVR is associated with overall comparable outcomes to TF TAVR in high-risk patient cohorts, despite higher incidences of major comorbidities in the TAx-TAVR patient population. The rate of AKI appears to be lower after TAx-TAVR.

Carotid Stenosis in Cardiac Surgery-No Difference in Postoperative Outcomes.

BACKGROUND: Debate over revascularization of asymptomatic carotid stenosis before cardiac surgery is ongoing. In this study, we analyze cardiac surgery outcomes in patients with asymptomatic carotid stenosis at a single hospital. METHODS: In this study, 1,781 patients underwent cardiac surgery from January 2012 to June 2013; 1,357 with preoperative screening carotid duplex were included. Patient demographics, comorbidities, degree of stenosis, postoperative complications, and mortality were evaluated. Chi-square test and logistic regression analysis were performed. RESULTS: Asymptomatic stenosis was found in 403/1,357 patients (29.7%; 355 moderate and 48 severe). Patients with stenosis, compared with those without, were older (71.7 ± 11 vs. 66.3 ± 12 years; p < 0.01). Females were more likely to have stenosis (odd ratio, = 1.7; 95% confidence interval, 1.4-2.2); however, patients were predominantly male in both groups. There were no significant differences in the rates of mortality and postoperative complications, including stroke and transient ischemic attack (TIA). Postoperative TIA occurred in 3/1,357(0.2%); only one had moderate stenosis. Inhospital stroke occurred in 21/1,357 (1.5%) patients; stroke rates were 2.3% (8/355) with moderate stenosis and 2.1% (1/48) severe stenosis. There were 59/1,357 (4.3%) deaths; patients with stenosis had a mortality rate of 4.2% (17/403); however, no postoperative stroke lead to death. Multivariable logistic regression analysis with adjustment for age, gender, race, comorbidities, and postoperative complications did not show an impact of carotid stenosis on postoperative mortality and development of stroke after cardiac surgery. CONCLUSION: This study suggests that patients with asymptomatic carotid stenosis undergoing cardiac surgery are not at increased risk of postoperative complications and mortality; thus, prophylactic carotid revascularization may not be indicated.

Patients with Infectious Endocarditis and Drug Dependence Have Worse Clinical Outcomes after Valvular Surgery.

BACKGROUND: Patients with infective endocarditis (IE) are at high risk for post-operative morbidity and death, which might be associated with drug abuse. The purpose of this study is to evaluate the impact of drug dependence on outcomes in patients who have IE and undergo valvular surgery (VS). PATIENTS AND METHODS: The Nationwide/National Inpatient Sample 2001-2012 was queried to select patients with IE who had elective VS using International Classification of Diseases, Ninth Revision, Clinical Modification diagnosis and procedure codes. Among them, patients with drug dependence (PDD) were identified, and their health status and post-operative outcomes were compared with those in patients without drug dependence (control group). Chi-square and Wilcoxon rank sum tests as well as multi-variable regression analysis were used for statistics. RESULTS: A total of 809 (12.9%) PDD of the 6,264 patients who underwent VS were evaluated. They were younger compared with those in the control group (39.0 ± 10.8 y vs. 54.4 ± 14.8 y; p < 0.0001), had less age-related co-morbidities such as hypertension, diabetes mellitus, congestive heart failure, renal failure, obesity, but greater rates of alcohol abuse, liver disease, and psychoses. Despite the younger age and fewer co-morbidities, PDD compared with control patients were more likely to have post-operative complications develop overall (odds ratio [OR] = 1.6; 95% confidence interval [CI] 1.34-2.01), including infectious complications (OR = 1.5; 95% CI 1.27-1.78), specifically pneumonia (OR = 1.4; 95% CI 1.14-1.74) and sepsis (OR = 1.4; 95% CI 1.16-1.63), renal complications (OR = 1.5; 95% CI 1.23-1.77), and pulmonary embolism (OR = 1.9; 95% CI 1.44-2.52). Further, PDD had 11% longer hospital length of stay than those in the control groups (p < 0.0001). We did not find significant difference in hospital deaths, however, between these groups. CONCLUSION: Drug dependence is associated with worse post-operative outcomes in patients with infective endocarditis who underwent valvular surgery and lengthens their hospital stay.

CREG1 Interacts with Sec8 to Promote Cardiomyogenic Differentiation and Cell-Cell Adhesion.

Understanding the regulation of cell-cell interactions during the formation of compact myocardial structures is important for achieving true cardiac regeneration through enhancing the integration of stem cell-derived cardiomyocytes into the recipient myocardium. In this study, we found that cellular repressor of E1A-stimulated genes 1 (CREG1) is highly expressed in both embryonic and adult hearts. Gain- and loss-of-function analyses demonstrated that CREG1 is required for differentiation of mouse embryonic stem (ES) cell into cardiomyocytes and the formation of cohesive myocardium-like structures in a cell-autonomous fashion. Furthermore, CREG1 directly interacts with Sec8 of the exocyst complex, which tethers vesicles to the plasma membrane. Site-directed mutagenesis and rescue of CREG1 knockout ES cells showed that CREG1 binding to Sec8 is required for cardiomyocyte differentiation and cohesion. Mechanistically, CREG1, Sec8, and N-cadherin colocalize at intercalated discs in vivo and are enriched at cell-cell junctions in cultured cardiomyocytes. CREG1 overexpression enhances the assembly of adherens and gap junctions. By contrast, its knockout inhibits the Sec8-N-cadherin interaction and induces their degradation. These results suggest that the CREG1 binding to Sec8 enhances the assembly of intercellular junctions and promotes cardiomyogenesis. Stem Cells 2016;34:2648-2660.

Femoral cannulation: a safe vascular access option for cardiopulmonary bypass in minimally invasive cardiac surgery.

Femoral cannulation during cardiopulmonary bypass has become a common approach for many cardiac procedures and serves as an important access option, especially during minimally invasive cardiac surgery. Opponents, however, argue that there is significant risk, including site-specific and overall morbidity, which makes the use of this modality dangerous compared to conventional aortoatrial cannulation techniques. We analyzed our institutional experience to elucidate the safety and efficacy of femoral cannulation. All data were collected from a single hospital's cardiac surgery database. A total of 346 cardiac surgeries were evaluated from September 2012 to September 2013, of which 85/346 (24.6%) utilized a minimally invasive approach. Of the 346 operations performed, 72/346 (20.8%) utilized femoral cannulation while 274/346 (79.2%) used aortoatrial cannulation. Stroke occurred in 1/72 (1.39%) after femoral cannulation, specifically, in a conventional sternotomy patient, while it occurred in 6/274 (2.19%) [p=0.67] after aortoatrial cannulation. When comparing postoperative complications between the femoral cannulation and aortoatrial cannulation groups, the rates of atrial fibrillation [10/72 (13.9%) versus 46/274 (16.8%), p=0.55], renal failure [2/72 (2.78%) versus 11/274 (4.01%), p=0.62], prolonged ventilation time [4/72 (5.56%) versus 27/274 (9.85%), p=0.26] and re-operation for bleeding [3/72 (4.17%) versus 13/274 (4.74%), p=0.84] showed no significant difference. Selective femoral cannulation provides a safe alternative to aortoatrial cannulation for cardiopulmonary bypass and is especially important when performing minimally invasive cardiac surgery. When comparing aortoatrial and femoral cannulation, we found no significant difference in the postoperative complication rates and overall mortality.

A chimeric embryoid body model to study vascular morphogenesis.

Embryonic stem cell (ESC)-derived embryoid body (EB) is a unique model for studying vascular development, in that it provides a three-dimensional microenvironment that mimics an in vivo milieu. When using gene-targeting EBs to study certain defects in vascular morphogenesis, it is necessary to determine whether the defect is due to the intrinsic loss of the gene in endothelial cells (EC) or rather due to the lack of surrounding factors that would typically promote vascular development. Here we describe a chimeric EB vessel development model, in which the utilization of the PECAM-GFP reporter gene in wild-type ESCs allows for the introduction of "normal" extracellular factors formed by its parallel differentiation to the gene-deletion EC that might otherwise be devoid of these factors.