Left Ventricular Hemodynamics and Relationship With Myocardial Recovery and Optimization in Patients Supported on CF-LVAD Therapy.

BACKGROUND: Despite interest in left ventricular (LV) recovery, there is an absence of data on the relationship between intrinsic LV hemodynamics and both reverse remodeling on a continuous flow LV assist device (CF-LVAD) therapy. We hypothesized that the markers of intrinsic LV function would be associated with remodeling, optimization, and outcomes. METHODS AND RESULTS: Patients with continuous flow LVADs between 2015 and 2019 who underwent combined left and right heart catheterization ramp protocol at a single institution were enrolled. Patients were stratified by response to continuous flow LV assist device therapy: full responders, partial responders, or nonresponders per the Utah-Inova criteria. Hemodynamic data, including LV hemodynamics of peak LV dP/dt and tau (τ) were obtained at each phase. The 1-year heart failure hospitalization-free survival was the primary end point. Among 61 patients included in the current study 38 (62%) were classified as nonresponders, 14 as partial responders (23%), and 9 as full responders (15%). The baseline LV dP/dt and τ varied by response status (P ≤ .02) and generally correlated with reverse remodeling on linear regression. Biventricular filling pressures varied with τ and there was an interaction effect of speed on the relationship between τ and pulmonary capillary wedge pressure (P = .04). Last, τ was a prognostic marker and associated with 1-year HF hospital-free survival (odds ratio 1.04, 95% confidence interval 1.00-1.07, P = .02 per millisecond increase). CONCLUSIONS: Significant correlations between τ and LV dP/dt and reverse remodeling were noted, with τ serving as a prognostic marker. A higher LVAD speed was associated with a greater reliance on LVAD for unloading. Future work should focus on defining the optimal level of LVAD support in relation to LV recovery.

De Ritis-adjusted AST provides comparable efficacy to lactate dehydrogenase as a biomarker for detection of LVAD hemolysis or thrombosis.

BACKGROUND: Lactate hydrogenase (LDH) is a common biomarker utilized in the detection and monitoring of left ventricular assist device (LVAD) hemolysis and thrombosis. Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) are common laboratory tests that can be used to calculate the De Ritis ratio and the De Ritis adjusted AST. METHODS: A retrospective review of LVAD patients was performed to identify three cohorts of patients: those with confirmed pump thrombosis after device exchange, those with LVAD-related hemolysis who were medically managed without pump exchange, and those who did not meet these criteria and served as the control cohort. Evaluation of AST, AST/ALT ratio (referred to as the De Ritis ratio) as well as AST x (AST/ALT) or the De Ritis-adjusted AST (DRA) was performed. RESULTS: There were 29 patients who underwent device exchange for thrombosis, 25 patients who were diagnosed with hemolysis and treated medically (clopidogrel (N = 6), heparin (N = 13), tirofiban (N = 8), eptifibatide (N = 2), and some received more than one of these treatments), and 425 control patients. A qualitatively comparable relative and absolute rise in DRA and LDH were found in both surgically managed pump thrombosis and suspected device-related hemolysis. CONCLUSIONS: Both AST and LDH as well DRA are significantly associated with pump thrombosis (p < 0.0001 for each). DRA is a potential screening biomarker for hemolysis and device thrombosis in stable left ventricular assist device patients.

Left ventricular assist devices: A historical perspective at the intersection of medicine and engineering.

Over the last half-century, left ventricular assist device (LVAD) technology has progressed from conceptual therapy for failed cardiopulmonary bypass weaning to an accepted destination therapy for advanced heart failure. The history of LVAD engineering is defined by an initial development phase, which demonstrated the feasibility of such an approach, to the more recent three major generations of commercial devices. In this review, we explore the engineering challenges of LVADs, how they were addressed over time, and the clinical outcomes that resulted from each major technological development. The first generation of commercial LVADs were pulsatile devices, which lacked the appropriate durability due to their number of moving components and hemocompatibility. The second generation of LVADs was defined by replacement of complex, pulsatile pumps with primarily axial, continuous-flow systems with an impeller in the blood passageway. These devices experienced significant commercial success, but the presence of excessive trauma to the blood and in-situ bearing resulted in an unacceptable burden of adverse events. Third generation centrifugal-flow pumps use magnetically suspended rotors within the pump chamber. Superior outcomes with this newest generation of devices have been observed, particularly with respect to hemocompatibility-related adverse events including pump thrombosis, with fully magnetically levitated devices. The future of LVAD engineering includes wireless charging foregoing percutaneous drivelines and more advanced pump control mechanisms, including synchronization of the pump flow with the native cardiac cycle, and varying pump output based on degree of physical exertion using sensor or advanced device-level data triggers.

Quality of life metrics in LVAD patients after hemocompatibility-related adverse events.

BACKGROUND: Hemocompatibility-related adverse events (HRAE) negatively influence survival. However, no study has examined the impact of these events on health-related quality of life (HRQOL) and functional outcomes following continuous-flow left ventricular assist device implantation (CF-LVAD). We assessed the impact of HRAE events on HRQOL and hypothesized that HRAE's adversely impact HRQOL and functional outcomes. METHODS: INTERMACS database identified patients undergoing primary CF-LVAD implantation from 2008 to 2017. HRAEs included stroke, non-surgical bleeding, hemolysis, and pump thrombosis and were identified as defined in the literature. HRAEs were further stratified as Tier 1-2 and disabling stroke events. Time-series analysis was executed for HRAE patients with values pre-HRAE, post-HRAE, and closest to 12 months follow up. Local polynomial regression curves modeling individual patients were superimposed into "spaghetti" plots. RESULTS: All HRQOL and functional metrics improved in patients over time, despite HRAE complications. However, these patient metrics were significantly reduced compared to the non-HRAE cohort. Advanced data visualization techniques noted a decline after experiencing an HRAE with a subsequent recovery to baseline levels or higher. Six-minute walk test (6MWT) was noted to be most affected in the post-HRAE period but recovered similar to other metrics. CONCLUSIONS: The burden of HRAE following CF-LVAD implantation did not negatively impact the quality of life. However, the 6MWT did not increase in the post-HRAE period in all HRAE patients. Improvement of heart failure symptoms after CF-LVAD coupled with optimal management following the HRAE act to preserve the enhanced quality of life.

Sequential organ failure assessment score improves survival prediction for left ventricular assist device recipients in intensive care.

BACKGROUND: Preoperative risk scores facilitate patient selection, but postoperative risk scores may offer valuable information for predicting outcomes. We hypothesized that the postoperative Sequential Organ Failure Assessment (SOFA) score would predict mortality after left ventricular assist device (LVAD) implantation. METHODS: We retrospectively reviewed data from 294 continuous-flow LVAD implantations performed at Mayo Clinic Rochester during 2007 to 2015. We calculated the EuroSCORE, HeartMate-II Risk Score, and RV Failure Risk Score from preoperative data and the APACHE III and Post Cardiac Surgery (POCAS) risk scores from postoperative data. Daily, maximum, and mean SOFA scores were calculated for the first 5 postoperative days. The area under receiver-operator characteristic curves (AUC) was calculated to compare the scoring systems' ability to predict 30-day, 90-day, and 1-year mortality. RESULTS: For the entire cohort, mortality was 5% at 30 days, 10% at 90 days, and 19% at 1 year. The Day 1 SOFA score had better discrimination for 30-day mortality (AUC 0.77) than the preoperative risk scores or the APACHE III and POCAS postoperative scores. The maximum SOFA score had the best discrimination for 30-day mortality (AUC 0.86), and the mean SOFA score had the best discrimination for 90-day mortality (AUC 0.82) and 1-year mortality (AUC 0.76). CONCLUSIONS: We observed that postoperative mean and maximum SOFA scores in LVAD recipients predict short-term and intermediate-term mortality better than preoperative risk scores do. However, because preoperative and postoperative risk scores each contribute unique information, they are best used in concert to predict outcomes after LVAD implantation.

Use of plasma late on cardiopulmonary bypass in patients undergoing left ventricular assist device implantation.

Coagulopathy is common during left ventricular assist device (LVAD) implantation, treatment of which can be challenging given the often-limited ability for the right ventricle to accommodate volume transfusion after device initiation with 20% to 40% of patients developing right ventricular failure (RVF). Transfusion of plasma late on cardiopulmonary bypass (CPB) combined with ultrafiltration may replace clotting factors while reducing volume administration. We compared outcomes in patients undergoing LVAD implantation receiving plasma on CPB and ultrafiltration with traditional transfusion practices. Co-primary outcomes needed for blood product transfusion in the first 6 and 24 hours after CPB. Secondary outcomes included metrics of morbidity and mortality. 396 patients were analyzed (59 plasma on CPB). Patients receiving plasma on CPB had a greater volume of blood products transfused (3764 vs. 2741 mL first 6 hours; 6059 vs. 4305 mL first 24 hours) in unadjusted analysis. In adjusted analysis, plasma transfusion on CPB with ultrafiltration had no significant effect on the primary outcomes of blood products given in the first 6 hours (estimated effect size 982 [-428, 2392] mL, P = .17) and 24 hours (estimated effect size 1076 [-904, 3057] mL, P = .29). Patients receiving plasma on CPB were more likely on either vasopressors or inotropes at 24 hours after ICU admission (P = .01), however, indices of coagulopathy and RVF were similar between groups. While prospective studies would be necessary to definitively evaluate the clinical utility of this strategy, no signal for benefit was observed suggesting plasma should not be used for this purpose.

The Triple HIT: Perioperative Management of Heparin-Induced Thrombocytopenia Using Plasma Exchange, Intravenous Immunoglobulin, and Protamine Infusion for Left Ventricular Assist Device Implantation.

Heparin-induced thrombocytopenia (HIT) is a serious complication in patients exposed to heparin, leading to thrombocytopenia and, potentially, thrombosis. This disorder is challenging in cardiac surgery when anticoagulation for cardiopulmonary bypass is required. Herein a patient with HIT who had active thrombosis and successfully underwent urgent left ventricular assist device implantation managed with plasma exchange, intravenous immunoglobulin, and protamine infusion is described. These therapies reduce the immune response to heparin and minimize thrombosis when heparin reexposure is planned. These approaches to perioperative management of HIT represent an attractive alternative to the use of non-heparin anticoagulants in the cardiac and vascular surgical population.

Outcomes of cardiac surgery in nonagenarians.

BACKGROUND: While advanced age can be considered by some a contraindication to open-heart surgery, there is a paucity of data regarding outcomes of cardiac surgery in nonagenarians. We, therefore, sought to investigate the outcomes of nonagenarians undergoing cardiac surgery. METHODS: A retrospective review of our institutional Society of Thoracic Surgeons database between 1993 and 2019 was performed. Among a total of 32,421 patients who underwent open-heart surgery, 134 patients (0.4%) were nonagenarians (50.7% females, median age 91.6 [interquartile range: 90.7-92.9]). A comparison was performed between nonagenarians and patients aged 80-89 years. A regression analysis was performed to evaluate factors associated with midterm mortality in nonagenarians. RESULTS: The incidence of cardiac surgery in nonagenarians has been stable over time, from 0.4% in (1993-2000), 0.5% in (2001-2010) to 0.4% in (2011-2019). Valve surgery and CABG+valve were higher in nonagenarians compared to octogenarians (44.8% vs. 25.6%, 39.6% vs. 30.7%, respectively), but CABG was lower (15.7% vs. 33.8%); p < .01. Urgent/emergent surgery status was similar between groups (p = .7). Operative mortality was similar in the two groups (6% vs. 4.6%, p = .5). Hospital complications were comparable between groups. CONCLUSION: Cardiac surgery in nonagenarians can be achieved with acceptable morbidity and mortality. This study can be a benchmark for risk stratification for cardiac surgery in this high-risk population.

Effects of mTOR inhibitor-related proteinuria on progression of cardiac allograft vasculopathy and outcomes among heart transplant recipients.

We have previously described the use of sirolimus (SRL) as primary immunosuppression following heart transplantation (HT). The advantages of this approach include attenuation of cardiac allograft vasculopathy (CAV), improvement in glomerular filtration rate (GFR), and reduced malignancy. However, in some patients SRL may cause significant proteinuria. We sought to investigate the prognostic value of proteinuria after conversion to SRL. CAV progression and adverse clinical events were studied. CAV progression was assessed by measuring the Δ change in plaque volume (PV) and plaque index (PI) per year using coronary intravascular ultrasound. Proteinuria was defined as Δ urine protein ≥300 mg/24 h at 1 year after conversion to SRL. Overall, 137 patients were analyzed (26% with proteinuria). Patients with proteinuria had significantly lower GFR (P = .005) but similar GFR during follow-up. Delta PV (P < .001) and Δ PI (P = .001) were significantly higher among patients with proteinuria after adjustment for baseline characteristics. Multivariate Cox regression analysis showed higher all-cause mortality (hazard ratio 3.8; P = .01) with proteinuria but similar risk of CAV-related events (P = .61). Our results indicate that proteinuria is a marker of baseline renal dysfunction, and that HT recipients who develop proteinuria after conversion to SRL have less attenuation of CAV progression and higher mortality risk.

Association of Aspirin Treatment With Cardiac Allograft Vasculopathy Progression and Adverse Outcomes After Heart Transplantation.

BACKGROUND: Enhanced platelet reactivity may play a role in cardiac allograft vasculopathy (CAV) progression. The use of antiplatelet agents after heart transplantation (HT) has been inconsistent and although aspirin (ASA) is often a part of the medication regimen after HT, limited evidence is available on its benefit. METHODS AND RESULTS: CAV progression was assessed by measuring the difference in plaque volume and plaque index between the last follow-up and the baseline coronary intravascular ultrasound examination. Overall, 529 HT recipients were retrospectively analyzed (337 had ≥2 intravascular ultrasound studies). The progression in plaque volume (P = .007) and plaque index (P = .002) was significantly attenuated among patients treated with early ASA (within the first year after HT). Over a 6.7-year follow-up, all-cause mortality was lower with early ASA compared with late or no ASA use (P < .001). No cardiac deaths were observed in the early ASA group, and the risk of CAV-related graft dysfunction was significantly lower in this group (P = .03). However, the composite of all CAV-related events (cardiac death, CAV-related graft dysfunction, or coronary angioplasty) was not significantly different between the groups (P = .16). CONCLUSIONS: Early ASA use after HT may delay CAV progression and decrease mortality and CAV-related graft dysfunction, but does not seem to affect overall CAV-associated events.

International Medical Graduates are Comparable to American Medical Graduates as General Surgery Interns.

BACKGROUND: International medical graduates (IMGs) are often relegated to preliminary positions in general surgery (GS) owing to uncertainties about the candidate's performance in the American healthcare setting. We aimed to determine the comparative performance of IMGs and American medical graduates (AMGs) at baseline and assess these trends over the course of their GS internship. METHODS: Evaluations of all IMG preliminary and AMG categorical interns from 2013 to 2017 at our GS residency program were obtained from three faculty members to score overall performance, technical skills, interpersonal communication, and medical knowledge on a 10-point Likert scale. Scores on the American Board of Surgery In-Training Exam, an in-house preparation test, United States Medical Licensing Exam, and performance during the biannual multistation objective assessments were compared between the two resident groups. RESULTS: Seventy-two interns (28 [39%] AMG categorical and 44 [61%] IMG preliminary) met inclusion criteria. The AMG group had significantly higher median Step 1 and Step 2 scores compared with our IMG group (243 versus 231, P = 0.002, and 250 versus 246, P = 0.03, respectively).Although in-house preparation test scores were higher among IMGs (median [interquartile range] of 36 [33-40] among AMGs and 38 [34-45] among IMGs; P = 0.002), there were no statistically significant differences between the American Board of Surgery In-Training Exam scores of the two groups. The median scores for the four faculty evaluation components were similar between the AMG (7, 8, 7, 7) and IMG resident groups (7, 7, 7, 7; P = nonsignificant). IMGs scored significantly higher in both biannual multistation objective assessments than AMGs (median [interquartile range] July: 59 [47-91] versus 55 [37-62], P = 0.005; January: 103 [86-116] versus 91 [87-104], P = 0.03). CONCLUSIONS: It is reassuring to confirm that no matter where they are from, great candidates can perform well as surgical interns in a GS training program.

Inadequate left ventricular unloading during ramp is associated with hospitalization or death during left ventricular assist device support.

A combined right and left-sided heart catheterization (RHC/LHC) protocol was recently reported to optimize patients supported by left ventricular assist device (LVAD). Using this platform, we sought to evaluate the prognostic significance of several hemodynamic indices, including left ventricular end-diastolic pressure (LVEDP) and transaortic gradient (peak aortic pressure - peak left ventricular pressure in systole, TAG). We evaluated all patients undergoing RHC/LHC at our institution from 2015 through 2018, and comprehensive clinical data were obtained. Primary end points were (1) a composite outcome that included hospitalization or death and (2) 1-year overall survival after catheterization. Forty-two patients were included in the analysis. Optimization resulted in normalization of hemodynamic parameters; all variables were significantly improved from baseline (P ≤ .05). On univariate modeling, final LVEDP was associated with the primary end point (hazard ratio [HR], 1.2 per 1-mm Hg increase; 95% CI, 1.1-1.3; P = .002). After adjusting for LVAD speed, TAG, and cardiac index in a multivariate model, the association between LVEDP and the composite end point remained significant (HR, 1.2 per 1-mm Hg increase; 95% CI, 1.1-1.4; P = .001). In the setting of LVAD support, inadequate LV unloading was a significant marker of poor outcomes with time, suggesting that LVEDP is a central prognostic marker in this population.

Intraoperative prothrombin complex concentrate administration and outcomes in patients undergoing left ventricular assist device implantation.

Prothrombin complex concentrate (PCC) administration has increased among cardiac surgery patients in recent years; however, use in LVAD implantation/exchange is not widespread due to the fear of thrombotic complications. The purpose of this study was to compare the clinical outcomes of patients undergoing LVAD implantation/exchange with intraoperative PCC administration versus traditional transfusion practices alone. Adult LVAD implants/exchanges at our institution between 2015 and 2018 were included. Patients were categorized as receiving intraoperative PCC or no-PCC (traditional). The primary outcome was the need for allogenic transfusion and transfusion volume at 48 hours after initial intensive care unit (ICU) admission. Secondary outcomes included metrics of morbidity and mortality. A total of 160 patients (39 PCC, 121 traditional) were analyzed. In unadjusted analysis, patients in the PCC group received lower intraoperative transfusion volumes compared to the traditional group although not statistically significant (1464 mL [IQR 796, 4876] vs. 2568 mL [IQR 1292, 3606]; P value .37). In the fully adjusted analysis, patients in the PCC group had increased odds of transfusion within 48 hours of ICU admission (OR 4.06, 95% CI: 1.35-12.20; P < .01); however, there was no significant difference in transfusion volumes (P = .09). Patients receiving PCCs had higher incidence of deep vein thrombosis (10.3% vs. 0%; P  < .01) and 30-day mortality (17.9% vs. 4.1%; P < .01). LVAD pump thrombosis occurred in 2.6% versus 0.8% in the PCC and traditional groups, respectively; P = .98. Patients undergoing LVAD implantation and exchange represent a complex surgical cohort. The results of this study suggest that the intraoperative PCC use during LVAD implant/exchange was associated with reduced intraoperative transfusions. Intraoperative PCC use was, however, associated with higher odds of postoperative transfusion, although transfusion volumes were not significantly different. While the deep vein thrombosis and 30-day mortality rates were higher in the PCC group, these results are likely related to the degree of surgical and patient complexity rather than PCC use itself. Further studies are needed to assess PCC use in this surgical cohort.

Outcomes of pericardiectomy for constrictive pericarditis following mediastinal irradiation.

BACKGROUND: Pericardiectomy for postradiation constrictive pericarditis has been reported to generally have unfavorable outcomes. This study sought to evaluate surgical outcomes in a large cohort of patients undergoing pericardiectomy for radiation-associated pericardial constriction. METHODS: A retrospective analysis of all patients (≥18 years) who underwent pericardiectomy for a diagnosis of constrictive pericarditis with a prior history of mediastinal irradiation from June 2002 to June 2019 was conducted. There were 100 patients (mean age 57.2 ± 10.1 years, 49% females) who met the inclusion criteria. Records were reviewed to look at the surgical approach, the extent of resection, early mortality, and late survival. RESULTS: The overall operative mortality was 10.1% (n = 10). The rate of operative mortality decreased over the study period; however, the test of the trend was not statistically significant (p = .062). Hodgkin's disease was the most common malignancy (64%) for which mediastinal radiation had been received. Only 27% of patients had an isolated pericardiectomy, and concomitant pericardiectomy and valve surgery were performed in 46% of patients. Radical resection was performed in 50% of patients, whereas 47% of patients underwent subtotal resection. Prolonged ventilation (26%), atrial fibrillation (21%), and pleural effusion (16%) were the most common postoperative complications. The overall 1, 5-, and 10-years survival was 73.6%, 53.4%, and 32.1%, respectively. Increasing age (hazard ratio, 1.044, 95% confidence interval 1.017-1.073) appeared to have a significant negative effect on overall survival in the univariate model. CONCLUSION: Pericardiectomy performed for radiation-associated constrictive pericarditis has poor long-term outcomes. The early mortality, though high (~10%), has been showing a decreasing trend in the test of time.

Outcomes of adult patients supported by extracorporeal membrane oxygenation (ECMO) following cardiopulmonary arrest. The Mayo Clinic experience.

INTRODUCTION: To describe our experience in use of extracorporeal life support (ECLS) as a rescue strategy in patients following cardiopulmonary resuscitation. METHODS: A retrospective analysis was performed for patients (n = 101) who received ECLS after cardiorespiratory arrest between May 2001 and December 2014. The primary outcome was survival to hospital discharge. RESULTS: In this cohort median (IQR) age was 56 (37-67) years, 53 (53%) were male, and 90 (89%) were Caucasian. Ventricular tachycardia or ventricular fibrillations were the initial cardiac rhythm in 49 (48.5%) and asystole/pulseless electrical activity in 37 (36.8%). Median (IQR) time to initiation of extracorporeal support from arrest time was 72 (43-170) min. The median (IQR) duration of support was 100 (47-157) hours. Renal failure (66%) and bleeding (66%) were the two most commonly observed complications during ECLS support. The survival to hospital discharge was seen in 47 (47%) patients, and good neurologic outcome (mRs 0-3) was seen in 29%. Acidosis, lactate and continuous renal replacement therapy were independent predictors of mortality. The median (IQR) intensive care unit stay was 14 (4-28) days and hospital stay was 17 (4-35) days. CONCLUSION: Our institutional experience with ECLS as a rescue measure following cardiac arrest is associated with improvement in mortality, and favorable neurologic status at hospital discharge.

Impact of postoperative complications after cardiac surgery on long-term survival.

PURPOSE: The impact of postoperative complications on long-term survival is not well characterized. We sought to study the prevalence of postoperative complications after cardiac surgery and their impact on long-term survival. METHODS: Operative survivors (n = 26,221) who underwent coronary artery bypass grafting (CABG) (n = 13,054, 49.8%), valve surgery (n = 8667, 33.1%) or combined CABG and valve surgery (n = 4500, 17.2%) from 1993 to 2019 were included in the study. Records were reviewed for postoperative complications and long-term survival. Propensity-match analysis was performed between patients who did and did not have a postoperative complication. The associations between postoperative complications and survival were assessed using a Cox-proportional model. RESULTS: Complications occurred in 17,463 (66.6%) of 26,221 operative survivors. A total of 17 postoperative complications were analyzed. Postoperative blood product use was the commonest (n = 12,397, 47.3%), followed by atrial fibrillation (n = 8399, 32.0%), prolonged ventilation (n = 2336, 8.9%), renal failure (n = 870, 3.3%), reoperation for bleeding (n = 859, 3.3%) and pacemaker/ICD insertion (n = 795, 3.0%). Stroke (hazard ratio [HR]: 1.55; 95% confidence interval [CI]: 1.36-1.77), renal failure (HR: 1.45; 95% CI: 1.33-1.58) and pneumonia (HR: 1.23; 95% CI: 1.11-1.36) had the strongest impact on long-term survival. Long-term survival decreased as the number of postoperative complications increased. CONCLUSIONS: Postoperative complications after cardiac surgery significantly impact outcomes that extend beyond the postoperative period. Stroke, renal failure, and pneumonia are particularly associated with poor long-term survival.

Cardiac surgeons' concerns, perceptions, and responses during the COVID-19 pandemic.

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic has had an unprecedented impact on health care and cardiac surgery. We report cardiac surgeons' concerns, perceptions, and responses during the COVID-19 pandemic. METHODS: A detailed survey was sent to recruit participating adult cardiac surgery centers in North America. Data regarding cardiac surgeons' perceptions and changes in practice were analyzed. RESULTS: Our study comprises 67 institutions with diverse geographic distribution across North America. Nurses were most likely to be redeployed (88%), followed by advanced care practitioners (69%), trainees (28%), and surgeons (25%). Examining surgeon concerns in regard to COVID-19, they were most worried with exposing their family to COVID-19 (81%), followed by contracting COVID-19 (68%), running out of personal protective equipment (PPE) (28%), and hospital resources (28%). In terms of PPE conservation strategies among users of N95 respirators, nearly half were recycling via decontamination with ultraviolet light (49%), followed by sterilization with heat (13%) and at home or with other modalities (13%). Reuse of N95 respirators for 1 day (22%), 1 week (21%) or 1 month (6%) was reported. There were differences in adoption of methods to conserve N95 respirators based on institutional pandemic phase and COVID-19 burden, with higher COVID-19 burden institutions more likely to resort to PPE conservation strategies. CONCLUSIONS: The present study demonstrates the impact of COVID-19 on North American cardiac surgeons. Our study should stimulate further discussions to identify optimal solutions to improve workforce preparedness for subsequent surges, as well as facilitate the navigation of future healthcare crises.

Amyloidosis in surgically resected atrial appendages: a study of 345 consecutive cases with clinical implications.

Histomorphologic parameters of atrial appendages removed during the Cox-Maze procedure have been shown to correlate with recurrence of atrial fibrillation. While amyloid deposition has been noted within atrial appendages, the incidence and significance remains incompletely understood. More accurate amyloid typing methodologies and targeted pharmacotherapeutics have recently been developed, prompting pathologists to provide more detailed information about the type of amyloid identified in such samples. This study sought to fully characterize the morphologic characteristics of atrial amyloid as well as its incidence and clinical significance. Tissue archives were queried for atrial appendages removed during the cardiac surgeries (2010-2014). Patient demographics, imaging features, and salient clinical findings were recorded. Pattern and extent of amyloid deposition were recorded. Typing of the amyloid protein, when present, was performed on a subset of cases by laser capture microdissection with mass spectrometry-based proteomic analysis. A total of 383 atrial appendages from 345 consecutive patients were included in the study (mean age, 69 years; range, 26-92 years). Amyloid was present in 46% of patients. A linear relationship was observed between age and presence of atrial amyloidosis. Women were more likely to have atrial amyloidosis. Two distinct morphologies of amyloid were observed: filamentous and nonfilamentous, and correlated perfectly with amyloid type (filamentous = AANF-type amyloid; nonfilamentous = ATTR-type amyloid). Filamentous deposits were observed in 91% of those with amyloid. Amyloid was more likely to be found in the left atrial appendage than the right. Patients with atrial amyloid, irrespective of type, were more likely to have experienced stroke or TIA and more likely to have atrial arrhythmia preoperatively. Postoperatively, those with atrial amyloid are more likely to experience recurrence of arrhythmia than those who did not have atrial amyloid. Understanding the morphologic characteristics of AANF-type amyloid will allow for identification by the light microscopy and obviates the need for expensive ancillary typing techniques. The finding of nonfilamentous amyloid, should still prompt confirmation of amyloid type so that targeted therapy may be employed.

Changes in Right Ventricle Function After Mitral Valve Repair Surgery.

BACKGROUND: Right ventricular (RV) dysfunction can occur after cardiac surgery and persist for years. We assessed perioperative RV systolic function in patients undergoing mitral valve (MV) repair and further compared minimally invasive robotic-assisted mitral valve repair (MIMVr) vs standard 'open' MV repair (MVr). Speckle tracking (RV free wall strain [RVS]) was used as a sensitive echocardiography method to assess RV function. METHODS: Retrospective analysis, over 3 years, of consecutive patients (n = 158) referred to Mayo Clinic (Rochester, MN, USA). Preoperative, pre-discharge and 1 year transthoracic echocardiograms were reviewed. A prospective pilot study was performed for sample size estimation. Primary outcome was RV free wall strain (RVS). RESULTS: Right ventricular free wall strain declined after MV repair surgery (-22.6 ± 7% vs -15 ± 6%, p < 0.001). There were smaller reductions in RVS in MIMVr vs MVr group (-6.0 ± 9% vs -10.3 ± 8%, p < 0.01), which persisted after adjusting for baseline values (RVS treatment effect 1.5%, p = 0.007). There was greater recovery in MIMVr vs MVr group at 1 year follow-up vs pre-surgery values (-3.4 ± 9% vs -8.1 ± 8% respectively, p < 0.001, RVS treatment effect 1.7%, p = 0.001). Bypass time was higher in the MIMVr group (80min ± 22 vs 40min ± 20, p < 0.0001). The echo findings remained significant correcting for age, pulmonary pressures and change in ejection fraction. CONCLUSIONS: Right ventricular systolic dysfunction is common after MV repair surgery. Deterioration in RV contraction is less pronounced following MIMVr vs MVr and is associated with enhanced RV functional recovery at 1 year, albeit not to preoperative levels. This may potentially be associated with clinical functional improvement but further studies are warranted to investigate this.

Intensive Care Unit Readmission After Left Ventricular Assist Device Implantation: Causes, Associated Factors, and Association With Patient Mortality.

BACKGROUND: Previous studies on readmissions after left ventricular assist device (LVAD) implantation have focused on hospital readmissions after dismissal from the index hospitalization. Because few data exist, the purpose of this study was to examine intensive care unit (ICU) readmissions in patients during their initial hospitalization for LVAD implantation to determine reasons for, factors associated with, and incidence of mortality after ICU readmission. METHODS: A retrospective analysis was performed from February 2007 to March 2015 of patients at our institution receiving first-time LVAD implantation. After LVAD implantation, patients dismissed from the ICU who then required ICU readmission before hospital dismissal were compared to those not requiring ICU readmission before hospital dismissal with respect to preoperative, intraoperative, and postoperative factors. RESULTS: Among 287 LVAD patients, 266 survived their initial ICU admission, of which 49 (18.4%) required ICU readmission. The most common reasons for readmission were bleeding and respiratory failure. Factors found to be univariably associated with ICU readmission were preoperative hemoglobin, preoperative aspartate aminotransferase, preoperative atrial fibrillation, preoperative dialysis, longer cardiopulmonary bypass times, and higher intraoperative allogeneic blood transfusion requirements. Multivariable analysis revealed ICU readmission to be independently associated with preoperative dialysis (odds ratio, 12.86; 95% confidence interval, 3.16-52.28; P < .001). Overall mortality at 1 year was 22.6%. Survival after hospital dismissal was worse for patients who required ICU readmission during the index hospitalization (adjusted hazard ratio, 2.35; 95% confidence interval, 1.15-4.81; P = .019). CONCLUSIONS: ICU readmission after LVAD implantation occurred relatively frequently and was significantly associated with 1-year mortality after hospital dismissal. These data can perhaps be used to identify subsets of LVAD patients at risk for ICU readmission and may lead to implementation of practice changes to mitigate ICU readmissions. Future larger and prospective studies are warranted.