Worse survival in patients with right ventricular dysfunction and COVID-19-associated acute respiratory distress requiring extracorporeal membrane oxygenation: A multicenter study from the ORACLE Group

OBJECTIVE

We sought to determine the impact of right ventricular dysfunction on the outcomes of mechanically ventilated patients with COVID-19 requiring veno-venous extracorporeal membrane oxygenation.

METHODS

Six academic centers conducted a retrospective analysis of mechanically ventilated patients with COVID-19 stratified by support with veno-venous extracorporeal membrane oxygenation during the first wave of the pandemic (March to August 2020). Echocardiograms performed for clinical indications were reviewed for right and left ventricular function. Baseline characteristics, hospitalization characteristics, and survival were compared.

RESULTS

The cohort included 424 mechanically ventilated patients with COVID-19, 126 of whom were cannulated for veno-venous extracorporeal membrane oxygenation. Right ventricular dysfunction was observed in 38.1% of patients who received extracorporeal membrane oxygenation and 27.4% of patients who did not receive extracorporeal membrane oxygenation with an echocardiogram. Biventricular dysfunction was observed in 5.5% of patients who received extracorporeal membrane oxygenation. Baseline patient characteristics were similar in both the extracorporeal membrane oxygenation and non-extracorporeal membrane oxygenation cohorts stratified by the presence of right ventricular dysfunction. In the extracorporeal membrane oxygenation cohort, right ventricular dysfunction was associated with increased inotrope use (66.7% vs 24.4%, P < .001), bleeding complications (77.1% vs 53.8%, P = .015), and worse survival independent of left ventricular dysfunction (39.6% vs 64.1%, P = .012). There was no significant difference in days ventilated before extracorporeal membrane oxygenation, length of hospital stay, hours on extracorporeal membrane oxygenation, duration of mechanical ventilation, vasopressor use, inhaled pulmonary vasodilator use, infectious complications, clotting complications, or stroke. The cohort without extracorporeal membrane oxygenation cohort demonstrated no statistically significant differences in in-hospital outcomes.

CONCLUSIONS

The presence of right ventricular dysfunction in patients with COVID-19-related acute respiratory distress syndrome supported with veno-venous extracorporeal membrane oxygenation was associated with increased in-hospital mortality. Additional studies are required to determine if mitigating right ventricular dysfunction in patients requiring veno-venous extracorporeal membrane oxygenation improves mortality.

Noteworthy in Cardiothoracic Surgery 2023

Noteworthy in Cardiothoracic Surgery 2023 summarizes a few of the most high-impact trials and provocative trends in cardiothoracic surgery and transplantation this past year. Transplantation using organs procured from donation after circulatory death (DCD) continues to increase, and the American Society of Transplant Surgeons released recommendations on best practices in 2023. We review a summary of data on the impact of DCD on heart and lung transplantation. There has been increased interest in extracorporeal life support (ECLS), particularly after the COVID-19 pandemic, and we review the results of the highly discussed ECLS-SHOCK trial, which randomized patients in cardiogenic shock with planned revascularization to ECLS vs usual care. With improving survival outcomes in complex aortic surgery, there is a need for higher-quality evidence to guide which cooling and cerebral perfusion strategies may optimize cognitive outcomes in these patients. We review the short-term outcomes of the GOT ICE trial (Cognitive Effects of Body Temperature During Hypothermic Circulatory Arrest), a multicenter, randomized controlled trial of three different nadir temperatures, evaluating outcomes in cognition and associated changes in functional magnetic resonance imaging. Finally, both the Society of Thoracic Surgeons (STS) and the American College of Cardiology, American Heart Association, American College of Chest Physicians and Heart Rhythm Society (ACC/AHA/ACCP/HRS) updated atrial fibrillation guidelines in 2023, and we review surgically relevant updates to the guidelines and the evidence behind them.

Association of procurement technique with organ yield and cost following donation after circulatory death

Donation after circulatory death (DCD) could account for the largest expansion of the donor allograft pool in the contemporary era. However, the organ yield and associated costs of normothermic regional perfusion (NRP) compared to super-rapid recovery (SRR) with ex-situ normothermic machine perfusion, remain unreported. The Organ Procurement and Transplantation Network (December 2019 to June 2023) was analyzed to determine the number of organs recovered per donor. A cost analysis was performed based on our institution's experience since 2022. Of 43 502 donors, 30 646 (70%) were donors after brain death (DBD), 12 536 (29%) DCD-SRR and 320 (0.7%) DCD-NRP. The mean number of organs recovered was 3.70 for DBD, 3.71 for DCD-NRP (P < .001), and 2.45 for DCD-SRR (P < .001). Following risk adjustment, DCD-NRP (adjusted odds ratio 1.34, confidence interval 1.04-1.75) and DCD-SRR (adjusted odds ratio 2.11, confidence interval 2.01-2.21; reference: DBD) remained associated with greater odds of allograft nonuse. Including incomplete and completed procurement runs, the total average cost of DCD-NRP was $9463.22 per donor. By conservative estimates, we found that approximately 31 donor allografts could be procured using DCD-NRP for the cost equivalent of 1 allograft procured via DCD-SRR with ex-situ normothermic machine perfusion. In conclusion, DCD-SRR procurements were associated with the lowest organ yield compared to other procurement methods. To facilitate broader adoption of DCD procurement, a comprehensive understanding of the trade-offs inherent in each technique is imperative.

Characterization of pulmonary arterial stiffness using cardiac MRI

Pulmonary arterial stiffness (PAS) is a pathologic hallmark of all types of pulmonary hypertension (PH). Cardiac MRI (CMR), a gold-standard imaging modality for the evaluation of pulmonary flow, biventricular morphology and function has been historically reserved for the longitudinal clinical follow-up, PH phenotyping purposes, right ventricular evaluation, and research purposes. Over the last two decades, numerous indices combining invasive catheterization and non-invasive CMR have been utilized to phenotype the character and severity of PAS in different types of PH and to assess its clinically prognostic potential with encouraging results. Many recent studies have demonstrated a strong role of CMR derived PAS markers in predicting long-term clinical outcomes and improving currently gold standard risk assessment provided by the REVEAL calculator. With the utilization of a machine learning strategies, strong diagnostic and prognostic performance of CMR reported in multicenter studies, and ability to detect PH at early stages, the non-invasive assessment of PAS is on verge of routine clinical utilization. In this review, we focus on appraising important CMR studies interrogating PAS over the last 20 years, describing the benefits and limitations of different PAS indices, and their pathophysiologic relevance to pulmonary vascular remodeling. We also discuss the role of CMR and PAS in clinical surveillance and phenotyping of PH, and the long-term future goal to utilize PAS as a biomarker to aid with more targeted therapeutic management.

Association of cardiac preservation solution with short-term outcomes after heart transplantation

AIMS

There is wide variability in the practice of cardiac preservation for heart transplantation. Prior reports suggest that the type of solution may be linked with a reduced incidence of posttransplantation complications.

METHODS

Adult (≥18 years old) heart recipients who underwent transplantation between 2015 and 2021 in the United States were examined. Recipients were stratified by solution utilized for their grafts at the time of recovery: University of Wisconsin, histidine-tryptophan-ketoglutarate (HTK), or Celsior solution. The primary endpoint was a composite of 30-day mortality, primary graft dysfunction, or re-transplantation. Risk adjustment was performed for the recipient, donor, and procedural characteristics using regression modeling.

RESULTS

Among 16 884 recipients, the group distribution was University of Wisconsin solution 53%, HTK 22%, Celsior solution 15%, and other 10%. The observed incidence of the composite endpoint (University of Wisconsin solution = 3.6%, HTK = 4.0%, Celsior solution = 3.7%, P = 0.301) and 1-year survival (University of Wisconsin solution = 91.7%, HTK = 91.3%, Celsior solution = 91.7%, log-rank P = 0.777) were similar between groups. After adjustment, HTK was associated with a higher risk of the composite endpoint [odds ratio (OR) 1.249, 95% confidence interval (CI) 1.019-1.525, P = 0.030] in reference to University of Wisconsin solution. This association was substantially increased among recipients with ischemic periods of greater than 4 h (OR 1.817, 95% CI 1.188-2.730, P = 0.005). The risks were similar between University of Wisconsin solution and Celsior solution (P = 0.454).

CONCLUSION

The use of the histidine-tryptophan-ketoglutarate solution during cold static storage for cardiac preservation is associated with increased rates of early mortality or primary graft dysfunction. Clinician discretion should guide its use, especially when prolonged ischemic times (>4 h) are anticipated.

Lung recovery utilizing thoracoabdominal normothermic regional perfusion during donation after circulatory death: The Colorado experience

Objective

Donation after circulatory death (DCD) procurement and transplantation after thoracoabdominal normothermic regional perfusion (TA-NRP) remains a novel technique to improve cardiac and hepatic allograft preservation but may be complicated by lung allograft pulmonary edema. We present a single-center series on early implementation of a lung-protective protocol with strategies to mitigate posttransplant pulmonary edema in DCD lung allografts after TA-NRP procurement.

Methods

Data from all lung transplantations performed using a TA-NRP procurement strategy from October 2022 to April 2023 are presented. Donor management consisted of key factors to reduce lung allograft pulmonary edema: aggressive predonation and early posttransplant diuresis, complete venous drainage at TA-NRP initiation, and early pulmonary artery venting upon initiation of systemic perfusion. Donor and recipient characteristics, procurement characteristics such as TA-NRP intervals, and 30-day postoperative outcomes were assessed.

Results

During the study period, 8 lung transplants were performed utilizing TA-NRP procurement from DCD donors. Donor ages ranged from 16 to 39 years and extubation time to declaration of death ranged from 10 to 90 minutes. Time from declaration to TA-NRP initiation was 7 to 17 minutes with TA-NRP perfusion times of 49 to 111 minutes. Median left and right allograft warm ischemia times were 55.5 minutes (interquartile range, 46.5-67.5 minutes) and 41.0 minutes (interquartile range, 39.0-53.0 minutes, respectively, with 2 recipients supported with cardiopulmonary bypass or venoarterial extracorporeal membrane oxygenation during implantation. No postoperative extracorporeal membrane oxygenation was required. There were no pulmonary-related deaths; however, 1 patient died from complications of severe necrotizing pancreatitis with a normal functioning allograft. All patients were extubated within 24 hours. Index intensive care unit length of stay ranged from 3 to 11 days with a hospital length of stay of 13 to 37 days.

Conclusions

Despite concern regarding quality of DCD lung allografts recovered using the TA-NRP technique, we report initial success using this procurement method. Implementation of strategies to mitigate pulmonary edema can result in acceptable outcomes following lung transplantation. Demonstration of short- and long-term safety and efficacy of this technique will become increasingly important as the use of TA-NRP for thoracic and abdominal allografts in DCD donors expands.

4D-Flow MRI intracardiac flow analysis considering different subtypes of pulmonary hypertension

Intracardiac flow hemodynamic patterns have been considered to be an early sign of diastolic dysfunction. In this study we investigated right ventricular (RV) diastolic dysfunction between patients with pulmonary arterial hypertension (PAH) and pulmonary hypertension with chronic lung disease (PH-CLD) via 4D-Flow cardiac MRI (CMR). Patients underwent prospective, comprehensive CMR for function and size including 4D-Flow CMR protocol for intracardiac flow visualization and analysis. RV early filling phase and peak atrial phase vorticity (E-vorticity and A-vorticity) values were calculated in all patients. Patients further underwent comprehensive Doppler and tissue Doppler evaluation for the RV diastolic dysfunction. In total 13 patients with PAH, 15 patients with PH-CLD, and 10 control subjects underwent the 4D-Flow CMR and echocardiography evaluation for RV diastolic dysfunction. Reduced E-vorticity differentiated PAH and PH-CLD from healthy controls (both p < 0.01) despite the same Doppler E values. E-vorticity was further decreased in PAH patients when compared to PH-CLD group (p < 0.05) with similar Doppler and tissue Doppler markers of diastolic dysfunction. A-vorticity was decreased in both PAH and PH-CLD groups compared to controls but with no difference between the disease groups. E-vorticity correlated with ejection fraction (R = 0.60, p < 0.001), end-systolic volume (R = 0.50, p = 0.001), stroke volume (R = 0.42, p = 0.007), and cardiac output (R = 0.30, p = 0.027). Intracardiac flow analysis using 4D-Flow CMR derived vorticity is a sensitive method to differentiate diastolic dysfunction in patients with different PH etiology and similar Doppler echocardiography profile.

Reduced Morbidity and Mortality Associated With Minimally Invasive Single-vessel Coronary Artery Bypass Compared With Conventional Sternotomy

OBJECTIVE

We aimed to describe the safety and clinical benefits of minimally invasive, nonsternotomy coronary artery bypass grafting (MICABG) using data from The Society of Thoracic Surgeons (STS) National Database.

BACKGROUND

MICABG has gained popularity, owing to expected lower perioperative morbidity and shorter recovery. Despite this, concerns remain regarding anastomotic quality and the validity of proposed perioperative benefits.

METHODS

We queried the STS National Database for all patients who underwent single-vessel coronary artery bypass grafting (CABG) from January 2014 to December 2016 to compare outcomes of MICABG with conventional CABG. Patients who underwent concomitant or emergent procedures were excluded. Propensity-weighted cohorts were compared by operative approach with adjustment for variability across institutions.

RESULTS

Of 12,406 eligible patients, 2688 (21.7%) underwent MICABG, and 9818 (78.3%) underwent conventional CABG. Propensity weighting produced excellent balance in patient characteristics, including completeness of revascularization, body mass index, and STS predictive risk scores. MICABG was associated with significant reduction of in-hospital mortality [odds ratio (OR)=0.32, absolute reduction (AR)=0.91%, P <0.0001]; 30-day mortality (OR=0.51, AR=0.88%, P =0.001), duration of ventilation (8.62 vs 12.6 hours, P <0.0001), prolonged hospitalization (OR=0.77, AR=1.6, P =0.043), deep wound infection (OR=0.33, AR=0.68, P <0.004), postoperative transfusions (OR=0.52, AR=7.7%, P <0.0001), and STS composite morbidity (OR=0.72, AR=1.19%, P =0.008). Subgroup analysis of only off-pump left internal mammary artery-left anterior descending CABG showed similar findings. Major adverse cardiac events and graft occlusion did not differ between groups.

CONCLUSIONS

MICABG is associated with lower mortality and perioperative morbidity compared with conventional sternotomy CABG. MICABG may have a role in treating single-vessel disease.

Extracorporeal membrane oxygenation for COVID-19: an evolving experience through multiple waves

Background

Extracorporeal membrane oxygenation (ECMO) has shown variable results in COVID‐19 pneumonia however, some evidence supports benefit. Here we compare our institution's ECMO outcomes across multiple waves of the COVID‐19 pandemic.

Methods

All patients who received ECMO for COVID‐19 between March 1, 2020, and March 1, 2021, were reviewed. Patients received venovenous (VV) or right ventricular assist device (RVAD/ECMO) ECMO. Early (March 1–July 6, 2020, Era 1) and late (July 7, 2020–March 1, 2021, Era 2) pandemic RVAD/ECMO patients were compared.

Results

Fifty‐four patients received ECMO of which 16 (29.6%) patients received VV ECMO and 38 (70.4%) RVAD/ECMO. Median age was 53.0 years, body mass index 36.1 kg/m², 41.2% female, and 49% Caucasian. The most common pre‐cannulation treatments included steroids (79.6%) and convalescent plasma (70.4%). Median time from admission to cannulation was 7.0 days. Median support time was 30.5 days (VV ECMO 35.0 days, RVAD/ECMO 26.0 days). In‐ hospital mortality was 42.6% (39.5% RVAD/ECMO, 50.0% VV ECMO). Significant morbidities included infection (80.8%), bleeding events (74.5%), and renal replacement therapy (30.8%). Cumulative mortality 120‐days post‐cannulation was 45.7% (VV ECMO 60.8%, RVAD/ECMO 40.0%). RVAD/ECMO Era 1 demonstrated a significantly lower cumulative mortality (16.2%) compared to Era 2 (60.4%). Competing risk analysis found age (HR 0.95, [95% CI 0.92, 0.98] p = 0.005) to be a protective factor for survival.

Conclusion

ECMO support for COVID‐19 is beneficial but carries significant morbidity. RVAD/ECMO support demonstrated consistent advantages in survival to VV‐ECMO, but with declining efficacy across time during the COVID‐19 pandemic.

Transcarotid Approach to Placement of an Impella 5.0

Microaxial left ventricular assist devices (mLVADs) have traditionally been placed through a transfemoral or transaxillary arterial approach. Transfemoral access is restrictive, significantly limiting postoperative patient ambulation. Transaxillary placement is preferred but not feasible in a subset of patients due to small arterial diameter or tight angulation of the thoracic outlet. Transcarotid delivery has been utilized for other cardiovascular device deployment with good success; however, this approach has not been described for mLVAD support. We present a case series of transcarotid placement of mLVADs in cases where a transaxillary and transfemoral approach was not feasible. From May 2017 to April 2019, six patients in cardiogenic shock required mLVAD support achieved via a transcarotid approach. Technical success was achieved in all patients. One patient was directly weaned from mLVAD support and two patients died on mLVAD support. Escalation to venoarterial extracorporeal membrane oxygenation (VA-ECMO) was required for three patients, two of whom subsequently died. There were no bleeding or valvular complications related to device placement, and no obvious or known neurologic complications related to mLVAD support. Transcarotid placement of mLVADs expands the utility of these devices as an alternative to traditional support strategies or prohibitive arterial anatomy; however, further study is needed to determine its efficacy.

Heart Transplant and Ventricular Assist: Cardiac Surgery and Heart Failure Perspective

For nearly 60 years, there have been two surgical treatment options for individuals with severe advanced heart failure: heart transplantation or implantation of a left ventricular assist device. As these fields have advanced in parallel, improvements in surgical technique, device development, and patient selection have improved outcomes for both therapies. Development of a comprehensive approach to the management of the most severe forms of advanced heart failure requires a deep understanding of both heart transplantation and durable ventricular assistance, including recent advancements in both fields. This article will review the substantial progress in the fields of heart transplantation and mechanical left ventricular assistance, including recent changes to organ allocation prioritization and left ventricular assist device evaluation, both of which have dramatically influenced practice in these fields.

Extracorporeal Membrane Oxygenation with Right Ventricular Assist Device for COVID-19 ARDS

Background: Right ventricular failure is an underrecognized consequence of COVID-19 pneumonia. Those with severe disease are treated with extracorporeal membrane oxygenation (ECMO) but with poor outcomes. Concomitant right ventricular assist device (RVAD) may be beneficial.

Methods: A retrospective analysis of intensive care unit patients admitted with COVID-19 ARDS (Acute Respiratory Distress Syndrome) was performed. Nonintubated patients, those with acute kidney injury, and age > 75 were excluded. Patients who underwent RVAD/ECMO support were compared with those managed via invasive mechanical ventilation (IMV) alone. The primary outcome was in-hospital mortality. Secondary outcomes included 30-d mortality, acute kidney injury, length of ICU stay, and duration of mechanical ventilation.

Results: A total of 145 patients were admitted to the ICU with COVID-19. Thirty-nine patients met inclusion criteria. Of these, 21 received IMV, and 18 received RVAD/ECMO. In-hospital (52.4 versus 11.1%, P = 0.008) and 30-d mortality (42.9 versus 5.6%, P= 0.011) were significantly lower in patients treated with RVAD/ECMO. Acute kidney injury occurred in 15 (71.4%) patients in the IMV group and zero RVAD/ECMO patients (P< 0.001). ICU (11.5 versus 21 d, P= 0.067) and hospital (14 versus 25.5 d, P = 0.054) length of stay were not significantly different. There were no RVAD/ECMO device complications. The duration of mechanical ventilation was not significantly different (10 versus 5 d, P = 0.44).

Conclusions: RVAD support at the time of ECMO initiation resulted in the no secondary end-organ damage and higher in-hospital and 30-d survival versus IMV in specially selected patients with severe COVID-19 ARDS. Management of severe COVID-19 ARDS should prioritize right ventricular support.

Do Right Heart Hemodynamic Improvements Persist After Pulmonary Thromboendarterectomy?

The survival benefits of pulmonary thromboendarterectomy (PTE) for the treatment of chronic thromboembolic pulmonary hypertension have been well described. However, the significance of right heart hemodynamic changes and their impact on survival remains poorly understood. We sought to characterize the effects of these changes. We conducted a single center, retrospective review of 159 patients who underwent PTE between 1993 and 2015. Echocardiographic and right heart catheterization data were compared longitudinally before and after PTE in order to establish the extent of hemodynamic response to surgery. Kaplan Meier estimates were used to characterize patient survival over time. Univariable and multivariable Cox proportional hazards regression models were used to assess factors associated with long-term mortality. Among the 159 patients studied, 74 (46.5%) were male with a median age of 55 (IQR: 42-66). One-, 5-, 10-, and 15-year survival was 91.0% (95% CI: 86.6-95.6), 79.6% (73.5-86.3), 66.5% (59.2-74.7), and 56.2% (48.1-65.8). Of the 9 candidate risk factors that were evaluated, only advanced age and increased cardiopulmonary bypass time were found to be significantly associated with increased risk of mortality. Pre- and postsurgical echocardiographic imaging data, when available, revealed a median reduction in right ventricular systolic pressure of 29.0 mm Hg (P < 0.0001) and improvement of tricuspid regurgitation (P < 0.0001), both of which appeared to be sustained across long-term follow-up. Improvements in right heart hemodynamics and tricuspid valvular regurgitation persist on long term surveillance following PTE. While patient selection is often driven by the distribution of disease, close postoperative follow up may improve outcomes.

Physiological Parameters of Bone Health in Elite Ballet Dancers

Stress fractures are common among elite ballet dancers whereby musculoskeletal health may be affected by energy balance and overtraining.

PURPOSE

This study aimed to characterize bone health in relation to stress fracture history, body composition, eating disorder risk, and blood biomarkers in professional male and female ballet dancers.

METHODS

A single cohort of 112 dancers (male: 55, 25 ± 6 yr; female: 57, 24 ± 6 yr) was recruited. All participants underwent bone and body composition measures using dual-energy x-ray absorptiometry. In a subset of our cohort (male: 30, 24 ± 6 yr; female, 29, 23 ± 5 yr), a blood panel, disordered eating screen, menstrual history, and stress fracture history were also collected. Age-matched Z scores and young-adult T scores were calculated for bone mineral density (BMD) and body composition. Independent-samples t-tests and Fisher's exact tests were used to compare BMD, Z-scores, T scores, and those with and without history of stress fractures. A 1 × 3 ANOVA was used to compare BMD for those scoring 0-1, 2-6, and 7+ using the EAT26 questionnaire for eating disorder risk. Regression was used to predict BMD from demographic and body composition measures.

RESULTS

Female dancers demonstrated reduced spinal (42nd percentile, 10%T < -1) and pelvic (16th percentile, 76%T < -1) BMD. Several anthropometric measures were predictive of BMD (P < 0.05, r = 0.65-0.81, standard error of estimate = 0.08-0.10 g·cm, percent error = 6.3-8.5). Those scoring >1 on EAT26 had lower BMD than did those with a score of 0-1 (P < 0.05).

CONCLUSIONS

Professional female ballet dancers exhibit reduced BMD, fat mass, and lean mass compared with the general population whereby low BMD and stress fractures tend to be more prevalent in those with a higher risk of disordered eating. Anthropometric and demographic measures are predictive of BMD in this population.

A Dual-Lumen Percutaneous Cannula for Managing Refractory Right Ventricular Failure

A right ventricular assist device (RVAD) using a dual-lumen percutaneous cannula inserted through the right internal jugular vein (IJV) might improve weaning in patients with refractory right ventricular (RV) failure. However, the reported experience with this cannula is limited. We reviewed the records of all patients receiving RVAD support with this new dual-lumen cannula at our institution between April 2017 and February 2019. We recorded data on weaning, mortality, and device-specific complications. We compared outcomes among three subgroups based on the indications for RVAD support (postcardiotomy, cardiogenic shock, and primary respiratory failure) and against similar results in the literature. Mean (standard deviation [SD]) age of the 40 patients (29 men) was 53 (15.5) years. Indications for implantation were postcardiotomy support in 18 patients, cardiogenic shock in 12, and respiratory failure in 10. In all, 17 (94%) patients in the postcardiotomy group were weaned from RVAD support, five (42%) in the cardiogenic shock group, and seven (70%) in the respiratory failure group, overall higher than those reported in the literature (49% to 59%) for surgically placed RVADs. Whereas published in-hospital mortality rates range from 42% to 50% for surgically placed RVADs and from 41% to 50% for RVADs with percutaneous cannulas implanted through the right IJV, mortality was 11%, 58%, and 40% in our subgroups, respectively. There were no major device-related complications. This percutaneous dual-lumen cannula appears to be safe and effective for managing refractory RV failure, with improved weaning and mortality profile, and with limited device-specific adverse events.

Minimally Invasive Mechanical Circulatory Support Through the Perioperative Pulmonary Thromboendarterectomy Period: A Case Report

A 64-year-old man being evaluated for pulmonary thromboendarterectomy (PTE) preoperatively experienced pulseless electrical activity secondary to right ventricular failure while undergoing bronchoscopy. After return of spontaneous circulation, a percutaneous right ventricular assist device (RVAD) was placed through the right internal jugular vein. He continued on right ventricular support with demonstration of right ventricular recovery over the following 8 days, and subsequently underwent PTE for treatment of his primary condition. He recovered and was weaned from his RVAD support uneventfully. The need for RVAD support has traditionally been a contraindication for PTE; however, circulatory assist devices have been used as a salvage procedure for right-heart failure after PTE. This case highlights the potential for percutaneous mechanical circulatory support in treating severe perioperative right ventricular dysfunction, and to facilitate successful recovery in patients undergoing PTE.

Minimally invasive single-vessel left internal mammary to left anterior descending artery bypass grafting improves outcomes over conventional sternotomy: A single-institution retrospective cohort study

BACKGROUND

Coronary artery bypass grafting (CABG) can be performed through a variety of approaches. Minimally-invasive CABG (MICABG) may reduce perioperative morbidity. Previous results demonstrate improved perioperative outcomes; however, adoption has been limited.

METHODS

The Society of Thoracic Surgeons (STS) database and electronic medical record at a single institution were reviewed for isolated left internal mammary to left anterior descending artery (LIMA-LAD) bypass procedures performed between 2011 and 2018. Patients were grouped on the basis of operative approach, comparing sternotomy to non-sternotomy (minimally-invasive). Patient characteristics, perioperative variables, and short- and long-term outcomes were compared. Primary outcomes included mortality and major adverse cardiac events (MACE). Secondary outcomes were morbidity.

RESULTS

A total of 42 MICABG and 54 conventional LIMA-LAD procedures were performed with 95.2% of MICABG procedures performed by two surgeons. MICABG were more often elective (83.3 vs 38.9%, P < .001). STS risk scores predicted equitable mortality and morbidity for MICABG dependent on operative indication. MICABG was associated with fewer pulmonary complications (0.0 vs 11.1%, P = .033), in-hospital events (11.9 vs 37.0%, P = .005), and shorter intensive care unit (34.1 vs 66.0 hours, P = .022) and total length of stay (3.7 vs 6.5 days, P = .002). There were no observed strokes, myocardial infarctions, or reoperations. MICABG patients demonstrated reduced thirty-day mortality (0.0 vs 10.9%, P = .036) and improved Kaplan-Meier 5-year (95.2 vs 77.9%, P = .016) and MACE-free survival (89.2 vs 63.9%, P = .010).

CONCLUSIONS

Minimally-invasive LIMA-LAD CABG demonstrates improved early postoperative morbidity and a long-term mortality benefit. In select patients, minimally-invasive approaches to single-vessel grafting may be beneficial when performed by experienced surgeons in the elective setting.

A Novel Technique to Repair Acute and Chronic Proximal Hamstring Avulsions

Treatment of proximal hamstring avulsions is challenging regarding both timing and choice of repair. In chronic situations, the tissue can become attenuated, bringing into question the need for adjunctive allograft. In general, proximal hamstring avulsions are affixed back to the ischial tuberosity with suture anchors, with allograft used as needed for chronic situations. This article reports on a novel technique of suspensory fixation with a unicortical button but without allograft to repair both acute and chronic proximal hamstring avulsions. Three patients, all of whom regained full strength and functionality 1 year postoperatively, are described. [Orthopedics. 2018; 41(2):116-119.].

Transposition of the great arteries--outcomes and time interval of early neonatal repair

BACKGROUND

This study evaluates the relationship of morbidity and resource utilization with the timing of early neonatal repair of transposition of the great arteries and intact ventricular septum (d-TGA/IVS).

METHODS

All patients with d-TGA/IVS who underwent arterial switch in the first 14 days of life, between January 2000 and May 2011, were reviewed. Patients undergoing repair at ≤ 4 days of age were categorized as group I, 5 to 7 days as group II, and 8 to 14 days as group III. Outcomes included mortality, morbidity, and resource utilization.

RESULTS

Hospital survival was 69 (98.6%) of 70. The length of stay (LOS) and total charges were lowest in group I--15.5 days compared to group II--18.0 days and group III--23.5 days (P = .005); group I--US$128,219 compared to group II--US$141,729 and group III--US$217,427 (P = .0006). Using regression analysis to account for potentially confounding effects of multiple variables and treating time as a continuous variable demonstrated that age at surgery was significantly associated with total LOS (P = .029), hospital charges (P = .029) and intensive care unit charges (P = .002). Younger age at repair was not associated with worse outcomes for any measure of morbidity.

CONCLUSIONS

Earlier repair of d-TGA/IVS was associated with decreased resource utilization and no detriment to clinical outcomes. Further analysis based on a larger cohort of patients is needed to verify these results that have important implications for improving the value of care.

Interface of Candida albicans biofilm matrix-associated drug resistance and cell wall integrity regulation

Candida albicans frequently infects medical devices by growing as a biofilm, i.e., a community of adherent organisms entrenched in an extracellular matrix. During biofilm growth, Candida spp. acquire the ability to resist high concentrations of antifungal drugs. One recently recognized biofilm resistance mechanism involves drug sequestration by matrix β-1,3 glucan. Using a candidate gene approach, we investigated potential C. albicans β-1,3-glucan regulators, based on their homology to Saccharomyces cerevisiae, including SMI1 and protein kinase C (PKC) pathway components. We identified a role for the SMI1 in biofilm matrix glucan production and development of the associated drug resistance phenotype. This pathway appears to act through transcription factor Rlmp and glucan synthase Fks1p. The phenotypes of these mutant biofilms mimicked those of the smi1Δ/smi1Δ biofilm, and overexpression of FKS1 in the smi1Δ/smi1Δ mutant restored the biofilm resistant phenotype. However, control of this pathway is distinct from that of the upstream PKC pathway because the pkc1Δ/pkc1Δ, bck1Δ/bck1Δ, mkk2Δ/mkk2Δ, and mkc1Δ/mkc1Δ biofilms retained the resistant phenotype of the parent strain. In addition, resistance to cell-perturbing agents and gene expression data do not support a significant role for the cell wall integrity pathway during the biofilm formation. Here we show that Smi1p functions in conjunction with Rlm1p and Fks1p to produce drug-sequestering biofilm β-glucan. Our work provides new insight into how the C. albicans biofilm matrix production and drug resistance pathways intersect with the planktonic cell wall integrity pathway. This novel connection helps explain how pathogens in a multicellular biofilm community are protected from anti-infective therapy.

Optimizing a Candida biofilm microtiter plate model for measurement of antifungal susceptibility by tetrazolium salt assay

Candida spp. infect medical devices, such as venous and urinary catheters, by adhering to the surface and forming a community of drug-resistant cells surrounded by a matrix. The ability to measure drug activity during this biofilm mode of growth is of interest for the investigation of resistance mechanisms and novel antifungal therapies. The tetrazolium salt (XTT) reduction assay is the test most commonly used to estimate viable biofilm growth and to examine the impact of biofilm therapies. The primary goal of the current experiments was to identify assay variables that affect the XTT assay result in order to improve assay reproducibility, sensitivity, and throughput for the study of antifungal activity. The species used in the current studies included Candida albicans, C. parapsilosis, and C. glabrata. The assay variables that were studied included the impact of culture conditions, the duration of biofilm growth, the timing and frequency of drug administration, the XTT source and concentration, and the duration of XTT incubation. The conditions that impacted the assay readout and altered assay sensitivity included the duration of biofilm growth, the frequency of drug dosing, and the duration of XTT incubation. Several factors were found to reduce time and assay expense, including the elimination of washing steps, the shortening of incubation times, and the use of lower XTT concentrations. A description of assay pitfalls and troubleshooting is included. Recognition of these technical variables should allow investigators to better design reproducible biofilm therapeutic studies.

Genetic basis of Candida biofilm resistance due to drug-sequestering matrix glucan

Medical devices provide an ecological niche for microbes to flourish as a biofilm community, protected from antimicrobials and host defenses. Biofilms formed by Candida albicans, the most common fungal pathogen, survive exposure to extraordinarily high drug concentrations. Here, we show that beta-glucan synthase Fks1p produces glucan, which is deposited in the biofilm matrix. The extracellular glucan is required for biofilm resistance and acts by sequestering antifungals, rendering cells resistant to their action. These findings provide the genetic basis for how biofilm matrix production governs drug resistance by impeding drug diffusion and also identify a useful biofilm drug target.

A reading-level design study of phonological skills underlying fourth-grade children's word reading difficulties

A 3-group reading-level design was used to investigate phonological analysis, verbal working memory, and pseudoword reading performance in less skilled fourth-grade readers. Children were given phonological oddity tasks assessing their sensitivity to subsyllabic and phonemic units, together with standardized tests of verbal working memory and pseudoword reading. Less skilled fourth-grade readers performed lower than both chronological age and reading-level controls on the phonological oddity and pseudoword reading tests. Less skilled fourth-grade readers performed at the same level as skilled second-grade readers on a test of verbal working memory. Skilled fourth-grade readers scored higher than both other groups on this test. Correlational analyses were consistent with the view that phonological analysis skills contribute more strongly than verbal working memory skills to children's decoding abilities.