Insurance-Based Disparities in Outcomes and ECMO Utilization for Hospitalized COVID-19 Patients

BACKGROUND

The objective of this study was to examine insurance-based disparities in mortality, non-home discharges, and ECMO utilization in patients hospitalized with COVID-19.

METHODS

Using a national database of U.S. academic medical centers and their affiliated hospitals, the risk-adjusted association between mortality, non-home discharge, and ECMO utilization and (1) the type of insurance coverage (private insurance, Medicare, dual enrollment in Medicare and Medicaid, and no insurance) and (2) the weekly hospital COVID-19 burden (0-5.0%; 5.1-10%, 10.1-20%, 20.1-30%, 30.1%-) was evaluated. Modelling was expanded to include an interaction between payer status and the weekly hospital COVID-19 burden to examine whether the lack of private insurance was associated with increases in disparities as the COVID-19 burden increased.

RESULTS

Among 760,846 patients hospitalized with COVID-19, 214,992 had private insurance, 318,624 had Medicare, 96,192 were dually enrolled in Medicare and Medicaid, 107,548 had Medicaid, and 23,560 had no insurance. Overall, 76,250 died, 211,702 had non-home discharges, 75,703 were mechanically ventilated, and 2,642 underwent ECMO. The adjusted odds of death were higher in patients with Medicare (aOR 1.28; [95% CI: 1.21, 1.35]; P<0.0005), dually enrolled (aOR, 1.39; [1.30, 1.50]; P<0.0005), Medicaid (aOR, 1.28; [1.20, 1.36]; P<0.0005), and no insurance (aOR, 1.43; [1.26, 1.62]; P<0.0005) compared to patients with private insurance. Patients with Medicare (aOR, 0.47; [CI: 0.39, 0.58]; P <0.0005), dually enrolled (aOR, 0.32; [0.24, 0.43]; P<0.0005), Medicaid (aOR, 0.70; [ 0.62, 0.79]; P<0.0005), and no insurance (aOR, 0.40; [0.29, 0.56]; P<0.001] were less likely to be placed on ECMO than patients with private insurance. Mortality, non-home discharges, and ECMO utilization did not change significantly more in patients with private insurance compared to patients without private insurance as the COVID-19 burden increased.

CONCLUSION

Among patients with COVID-19, insurance-based disparities in mortality, non-home discharges, and ECMO utilization were substantial, but these disparities did not increase as the hospital COVID-19 burden increased.

Ventricular Assist Device using a Thoracotomybased Implant Technique: Multi-center HeartMate 3 SWIFT Study

OBJECTIVES

The HeartMate 3 (HM3) left ventricular assist device (LVAD) provides substantial improvement in long-term morbidity and mortality in advanced heart failure patients. The SWIFT study compares thoracotomy-based implantation clinical outcomes with standard median sternotomy.

METHODS

We conducted a prospective, multicenter, single-arm study in patients eligible for HM3 implantation with thoracotomy-based surgical technique (bilateral thoracotomy or partial upper sternotomy with left thoracotomy). The composite primary endpoint was survival free of disabling stroke (Modified Rankin Score > 3), or reoperation to remove or replace a malfunctioning device, or conversion to median sternotomy at 6-months post-implant (elective transplants were treated as a success). The primary end point (non-inferiority, -15% margin) was assessed with >90% power compared to a propensity-matched cohort (ratio 1:2) derived from MOMENTUM 3 Continued Access Protocol (CAP).

RESULTS

The study enrolled 102 patients between December 2020 and July 2022 in the thoracotomy-based arm at 23 North American Centers. Follow-up concluded in December 2022. In the SWIFT group non-inferiority criteria was met (absolute between-group difference, -1.2%; Farrington Manning lower, one-sided 95%CI: -9.3%, P<0.0025) and event-free survival was not different (85.0% versus 86.2%; HR 1.01, 95%CI 0.58-2.10). Length of stay with thoracotomy-based implant was longer (median 20 versus 17 days, p=0.03). No differences were observed for blood product utilization, adverse events (including right heart failure), functional status, and quality of life between cohorts.

CONCLUSION

Thoracotomy-based implantation of the HM3 LVAD is non-inferior to implantation via standard full sternotomy. This study supports thoracotomy-based implantation as an additional standard for surgical implantation of the HM3 LVAD.

Cannula-Associated Deep Vein Thrombosis After Venovenous Extracorporeal Membrane Oxygenation in Patients with and Without Systemic Anticoagulation

OBJECTIVE

To identify and compare the rates of cannula-associated deep vein thrombosis (CaDVT) in patients on venovenous extracorporeal membrane oxygenation (VV-ECMO) who receive systemic anticoagulation (AC) and those who do not receive AC.

DESIGN

Retrospective observational study.

SETTING

Tertiary academic medical center.

PARTICIPANTS

Consecutive patients who successfully have been decannulated from VV-ECMO for treatment of refractory acute respiratory distress syndrome between 2017 and 2022.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

After decannulation of ECMO, a duplex sonograph was performed on the cannulation sites to determine the incidence and characteristics of cannula-related thrombosis. Thrombosis was classified as occlusive or nearly occlusive. Ninety-four of 161 patients were weaned from VV-ECMO. Nineteen patients who were placed on VV-ECMO due to COVID-19 were excluded. Twenty-seven of 52 patients (52%) who did not receive AC were identified to have thrombus. Twelve of 23 patients (52%) who received AC were identified to have thrombus. Patients who received AC required more blood products during the ECMO run and required longer support on VV-ECMO.

CONCLUSION

This study showed a high incidence of cannula-related venous thrombosis after VV-ECMO decannulation. Surprisingly, the incidence of CaDVT in anticoagulation-free patients was the same as in patients requiring anticoagulation. Anticoagulated patients required longer support on VV-ECMO and required more transfusions. Routine post-decannulation screening for DVT is recommended due to the high incidence of CaDVT.

Correlations Between Quantitative EEG Parameters and Cortical Blood Flow in Patients Undergoing Extracorporeal Membrane Oxygenation With and Without Encephalopathy

PURPOSE

The neurologic examination of patients undergoing extracorporeal membrane oxygenation (ECMO) is crucial for evaluating irreversible encephalopathy but is often obscured by sedation or neuromuscular blockade. Noninvasive neuromonitoring modalities including diffuse correlation spectroscopy and EEG measure cerebral perfusion and neuronal function, respectively. We hypothesized that encephalopathic ECMO patients with greater degree of irreversible cerebral injury demonstrate less correlation between electrographic activity and cerebral perfusion than those whose encephalopathy is attributable to medications.

METHODS

We performed a prospective observational study of adults undergoing ECMO who underwent simultaneous continuous EEG and diffuse correlation spectroscopy monitoring. (Alpha + beta)/delta ratio and alpha/delta Rartio derived from quantitative EEG analysis were correlated with frontal cortical blood flow index. Patients who awakened and followed commands during sedation pauses were included in group 1, whereas patients who could not follow commands for most neuromonitoring were placed in group 2. (Alpha + beta)/delta ratio-blood flow index and ADR-BFI correlations were compared between the groups.

RESULTS

Ten patients (five in each group) underwent 39 concomitant continuous EEG and diffuse correlation spectroscopy monitoring sessions. Four patients (80%) in each group received some form of analgosedation during neuromonitoring. (Alpha + beta)/delta ratio-blood flow index correlation was significantly lower in group 2 than group 1 (left: 0.05 vs. 0.52, P = 0.03; right: -0.12 vs. 0.39, P = 0.04). Group 2 ADR-BFI correlation was lower only over the right hemisphere (-0.06 vs. 0.47, P = 0.04).

CONCLUSIONS

Correlation between (alpha + beta)/delta ratio and blood flow index were decreased in encephalopathic ECMO patients compared with awake ones, regardless of the analgosedation use. The combined use of EEG and diffuse correlation spectroscopy may have utility in monitoring cerebral function in ECMO patients.

Design and characteristics of the prophylactic intra-operative ventricular arrhythmia ablation in high-risk LVAD candidates (PIVATAL) trial

BACKGROUND

The use of a Left Ventricular Assist Device (LVAD) in patients with advanced heart failure refractory to optimal medical management has progressed steadily over the past two decades. Data have demonstrated reduced LVAD efficacy, worse clinical outcome, and higher mortality for patients who experience significant ventricular tachyarrhythmia (VTA). We hypothesize that a novel prophylactic intra-operative VTA ablation protocol at the time of LVAD implantation may reduce the recurrent VTA and adverse events postimplant.

METHODS

We designed a prospective, multicenter, open-label, randomized-controlled clinical trial enrolling 100 patients who are LVAD candidates with a history of VTA in the previous 5 years. Enrolled patients will be randomized in a 1:1 fashion to intra-operative VTA ablation (n = 50) versus conventional medical management (n = 50) with LVAD implant. Arrhythmia outcomes data will be captured by an implantable cardioverter defibrillator (ICD) to monitor VTA events, with a uniform ICD programming protocol. Patients will be followed prospectively over a mean of 18 months (with a minimum of 9 months) after LVAD implantation to evaluate recurrent VTA, adverse events, and procedural outcomes. Secondary endpoints include right heart function/hemodynamics, healthcare utilization, and quality of life.

CONCLUSION

The primary aim of this first-ever randomized trial is to assess the efficacy of intra-operative ablation during LVAD surgery in reducing VTA recurrence and improving clinical outcomes for patients with a history of VTA.

Less Invasive Left Ventricular Assist Device Implantation Is Safe and Feasible in Patients With Smaller Body Surface Area

OBJECTIVE

Smaller body surface area (BSA) frequently precludes patients from left ventricular assist device (LVAD) therapy. We sought to investigate the clinical outcomes in patients with small BSA undergoing less invasive LVAD implantation.

METHODS

We conducted a retrospective review of 216 patients implanted with HeartMate 3 LVAD (Abbott, Chicago, IL) via less invasive surgery at our institution. Patients were dichotomized based on their preimplant BSA for comparison between small BSA (≤1.8 m2) and normal/large BSA (>1.8 m2). We analyzed patient perioperative characteristics and outcomes.

RESULTS

In our study, small BSA was found in 32 patients (14.8%), while 184 patients (85.2%) had normal/large BSA. Women were more prevalent in the small BSA group (50.0% vs 13.0%, P < 0.001). Preoperative and intraoperative data showed comparable results. Major complications and hospital length of stay did not differ by BSA group. Patients with smaller BSA had significantly decreased pump parameters at discharge, including LVAD flow (4.11 ± 0.49 vs 4.60 ± 0.54 L/min, P < 0.001) and pump speed (5,200 vs 5,400 rpm, P < 0.001). Survival to discharge and within 6 months after implantation were similar between the groups.

CONCLUSIONS

Our study results suggest that less invasive HeartMate 3 implantation can be safely performed and demonstrates equivalent outcomes in patients with smaller body habitus. Randomized trials are required to confirm our data.

Racial differences in clinical characteristics and readmission burden among patients with a left ventricular-assist device

BACKGROUND

There are limited data regarding racial disparities in outcomes after left ventricular assist device (LVAD) implantation. The purpose of this study was to compare clinical characteristics and the burden of readmissions by race among patients with LVAD.

METHODS

The study population included 461 patients implanted with LVADs at the University of Rochester Medical Center, NY from May 2008 to March 2020. Patients were stratified by race as White patients (N = 396 [86%]) and Black patients (N = 65 [14%]). The Anderson-Gill recurrent regression analysis was used to assess the independent association between race and the total number of admissions after LVAD implant during an average follow-up of 2.45 ± 2.30 years.

RESULTS

Black patients displayed significant differences in baseline clinical characteristics compared to White patients, including a younger age, a lower frequency of ischemic etiology, and a higher baseline serum creatinine. Black patients had a significantly higher burden of readmissions after LVAD implantation as compared with White patients 10 versus 7 (average number of hospitalizations per patient at 5 years of follow-up, respectively) translated into a significant 39% increased risk of recurrent readmissions after multivariate adjustment (Hazard ratio 1.39, 95% CI; 1.07-1.82, p 0.013).

CONCLUSION

Black LVAD patients experience an increased burden of readmissions compared with White patients, after adjustment for baseline differences in demographics and clinical characteristics. Future studies should assess the underlying mechanisms for this increased risk including the effect of social determinants of health on the risk of readmissions in LVAD recipients.

The Society of Thoracic Surgeons Intermacs 2022 Annual Report: Focus on the 2018 Heart Transplant Allocation System

The 13th annual report from The Society of Thoracic Surgeons (STS) Interagency Registry for Mechanically Assisted Circulatory Support (Intermacs) highlights outcomes for 27,314 patients receiving continuous-flow durable left ventricular assist devices (LVAD) during the last decade (2012-2021). In 2021, 2464 primary LVADs were implanted, representing a 23.5% reduction in the annual volume compared with peak implantation in 2019 and an ongoing trend from the prior year. This decline is likely a reflection of the untoward effects of the coronavirus disease 2019 pandemic and the change in the United States heart transplant allocation system in 2018. The last several years have been characterized by a shift in device indication and type, with 81.1% of patients now implanted as destination therapy and 92.7% receiving an LVAD with full magnetic levitation in 2021. However, despite an older, more ill population being increasingly supported preimplant with temporary circulatory devices in the recent (2017-2021) vs prior (2012-2016) eras, the 1- and 5-year survival continues to improve, at 83.0% and 51.9%, respectively. The adverse events profile has also improved, with a significant reduction in stroke, gastrointestinal bleeding, and hospital readmissions. Finally, we examined the impact of the change in the heart transplant allocation system in 2018 on LVAD candidacy, implant strategy, and outcomes. In the competing-outcomes analysis, the proportion of transplant-eligible patients receiving a transplant has declined from 56.5% to 46.0% at 3 years, whereas the proportion remaining alive with ongoing support has improved from 24.1% to 38.1% at 3 years, underscoring the durability of the currently available technology.

Mechanical Thrombectomy for Ischemic Stroke Secondary to Large Vessel Occlusions in Patients on Extracorporeal Membrane Oxygenation

INTRODUCTION

The use of short-term mechanical circulatory support (MCS) devices and procedures for function- and life-sustaining therapy is becoming a routine practice at many centers. Concomitant with the increasing use of MCS is the increasing recognition of acute brain injuries, including acute ischemic stroke, which may be caused by a myriad of MCS-driven factors. The aim of this case series was to document our experience with mechanical thrombectomy (MT) for ischemic stroke in extracorporeal membrane oxygenation (ECMO) patients.

METHODS

We retrospectively reviewed a prospectively maintained database of patients undergoing endovascular thrombectomy for large vessel occlusion at our institution. We identified patients that were on ECMO and underwent thrombectomy. Baseline demographics and procedural and functional outcomes were collected.

RESULTS

Three patients on ECMO were identified to have a large vessel occlusion and underwent thrombectomy. Two patients had an internal carotid artery terminus occlusion and one had a basilar artery occlusion. An mTICI 3 recanalization was achieved in all patients without postoperative hemorrhagic complications. Two patients achieved a 3-month mRS of 1, while one had mRS 4.

CONCLUSION

Ischemic stroke can be associated with significant morbidity in MCS patients. We demonstrate that MT can be safely performed in this patient population with good outcomes.

Left atrial appendage exclusion with less invasive left ventricular assist device implantation

OBJECTIVES

The objective of this single-center, pilot, prospective, and historical control study is to evaluate safety and feasibility outcomes associated with left atrial appendage exclusion (LAAE) concomitant with left ventricular assist device (LVAD) implantation via less invasive surgery (LIS) as a stroke prevention strategy.

METHODS

A predefined number of 30 eligible subjects scheduled for LIS LVAD with LAAE were enrolled in the prospective arm between January 2020 and February 2021. Eligible retrospective LIS LVAD patients without LAAE were propensity-matched in a 1:1 ratio with the prospective arm subjects. The primary study objectives were to evaluate the safety, feasibility, and efficacy of the LAAE concomitant with LIS LVAD.

RESULTS

Preoperative characteristics of patients in the Non-LAAE and LAAE groups were similar. LAAE was successfully excluded in all prospective patients (100%). Primary safety endpoints of chest tube output within the first 24 postoperative hours, Reoperation for bleeding within 48 h, and index hospitalization mortality demonstrated comparable safety of LAAE versus Non-LAAE with LIS LVAD. Cox proportional hazard regression demonstrated that LAAE with LIS LVAD was associated with 37% and 49% reduction in the risk of stroke and disabling stroke, respectively (p > .05).

CONCLUSION

Results from our pilot study demonstrated the safety and feasibility of LAAE concomitant with LIS LVAD as a stroke prevention strategy. This is the first prospective study describing LAAE performed concomitantly to less invasive LVAD implantation. The efficacy of LAAE in long-term stroke prevention needs to be confirmed in future prospective randomized clinical trials.

Novel Automated Suturing Technology for Minimally Invasive Mitral Chord Implantation: A Preclinical Evaluation Study

OBJECTIVE

This study evaluated the ergonomics and time requirements of using a novel automated suturing and titanium fastener deployment technology for chordal replacement in human heart specimens in open and minimally invasive cardiac surgery (MICS) simulators.

METHODS

Five cardiac surgeons used novel, manually powered expanded polytetrafluoroethylene (ePTFE) suturing devices to automate suture placement between mitral leaflets and papillary muscles in explanted cadaver hearts, along with customized titanium fastener delivery devices to secure suture and trim suture tails. This mitral chordal replacement test was conducted using surgical models simulating open and MICS mitral repair access. The study was approved by the institutional ethical board.

RESULTS

After a brief introduction to this technique using plastic models, study surgeons performed 48 chordal replacements in human mitral valves, placing 18 in an open model and 30 in a right minithoracotomy model. The time range to complete a single chordal replacement was between 55 s and 8 min, with an overall mean duration of 3.6 ± 1.5 min. No difference in duration of implantation was recorded for the MICS and open sternotomy simulators used. Good control of suture delivery was reported in 95.8% (n = 46) of leaflet aspect of the sutures and in 100% (N = 48) of papillary muscle sutures.

CONCLUSIONS

Automated mitral chordal ePTFE suturing simulated through open and MICS access demonstrated quality handling and accurate placement of sutures in human heart specimens. A clinical trial using this technology is currently ongoing. This innovation may present an important advance facilitating enhanced minimally invasive mitral valve repair.

Cognitive Change After Left Ventricular Assist Device Implantation: A Case Series and Systematic Review

BACKGROUND

Chronic cerebral hypoperfusion is a potential mechanism that causes cognitive impairment in patients with heart failure. Cognitive impairment in this population is associated with an increased mortality and poorer quality of life. Understanding the etiopathogenesis of cognitive impairment is crucial to developing effective treatment. A left ventricular assist device (LVAD) is a durable mechanical circulatory support device that restores systemic perfusion in patients with heart failure, potentially reversing cerebral hypoperfusion and cognitive impairment.

OBJECTIVE

This case series and systematic review examines the effect of LVAD implantation on cognition in patients with heart failure.

METHODS

We report a case series of 4 LVAD recipients at a tertiary academic center who underwent preimplant and postimplant cognitive testing. We also conducted a systematic review of studies with adult recipients of a continuous-flow LVAD whose cognition was measured before and after implantation. We searched Medline, EMBASE, SCOPUS, and the Cochrane library (start of database to July 16, 2021) for longitudinal, peer-reviewed studies written in English.

RESULTS

Cognitive improvement after LVAD implantation was observed in the case series, with improvement on phonemic fluency and digit symbol coding assessments. Two out of 4 cases in the case series improved on Clinical Dementia Rating: one from moderate dementia to mild cognitive impairment and another from mild cognitive impairment to unimpaired. Seven studies were included in the systematic review and were heterogeneous regarding cognitive tests employed, follow-up period, and measured outcomes. Montreal Cognitive Assessment and Trail-Making Test Part B were used most commonly. Cognitive improvement was reported in all 7 studies with at least 1 study reporting statistically significant improvements in each the following cognitive domains: delayed and immediate recall, executive function, visuospatial function, verbal function, attention, and processing speed. Most studies had small sample sizes and lacked a control group.

CONCLUSIONS

LVAD implantation appears to be associated with improved cognition. Adequately powered, prospective studies are needed to examine the effect of LVAD on cognitive function in patients with heart failure. Additionally, studies that directly examine cerebral blood flow in conjunction with cognitive assessment are needed to establish the relationship between the reversal of cerebral hypoperfusion and improved cognition.

Impact of surgical approach for left ventricular assist device implantation on postoperative invasive hemodynamics and right ventricular failure

BACKGROUND

Right ventricular failure (RVF) remains one of the major causes of morbidity and mortality after left ventricular assist device (LVAD) implantation. We sought to compare immediate postoperative invasive hemodynamics and the risk of RVF following two different surgical approaches: less invasive surgery (LIS) versus full sternotomy (FS).

METHODS

The study population comprised all 231 patients who underwent implantation of a HeartMate 3 (Abbott) LVAD at our institution from 2015 to 2020, utilizing an LIS (n = 161; 70%) versus FS (n = 70; 30%) surgical approach. Outcomes included postoperative invasive hemodynamic parameters, vasoactive-inotropic score (VIS), RVF during index hospitalization, and 6-month mortality.

RESULTS

Baseline clinical characteristics of the two groups were similar. Multivariate analysis showed that LIS, compared with FS, was associated with the improved cardiac index (CI) at the sixth postoperative hour (p = .036) and similar CI at 24 h, maintained by lower VIS at both timepoints (p = .002). The LIS versus FS approach was also associated with a three-fold lower incidence of in-hospital severe RVF (8.7% vs. 28.6%, p < .001) and need for RVAD support (5.0% vs. 17.1%, p = .003), and with 68% reduction in the risk of 6-month mortality after LVAD implantation (Hazard ratio, 0.32; CI, 0.13-0.78; p = .012).

CONCLUSION

Our findings suggest that LIS, compared with FS, is associated with a more favorable hemodynamic profile, as indicated by similar hemodynamic parameters maintained by lower vasoactive-inotropic support during the acute postoperative period. These findings were followed by a reduction in the risk of severe RVF and 6-month mortality in the LIS group.

Association Between the COVID-19 Pandemic and Insurance-Based Disparities in Mortality After Major Surgery Among US Adults

IMPORTANCE

The COVID-19 pandemic caused significant disruptions in surgical care. Whether these disruptions disproportionately impacted economically disadvantaged individuals is unknown.

OBJECTIVE

To evaluate the association between the COVID-19 pandemic and mortality after major surgery among patients with Medicaid insurance or without insurance compared with patients with commercial insurance.

DESIGN, SETTING, AND PARTICIPANTS

This cross-sectional study used data from the Vizient Clinical Database for patients who underwent major surgery at hospitals in the US between January 1, 2018, and May 31, 2020.

EXPOSURES

The hospital proportion of patients with COVID-19 during the first wave of COVID-19 cases between March 1 and May 31, 2020, stratified as low (≤5.0%), medium (5.1%-10.0%), high (10.1%-25.0%), and very high (>25.0%).

MAIN OUTCOMES AND MEASURES

The main outcome was inpatient mortality. The association between mortality after surgery and payer status as a function of the proportion of hospitalized patients with COVID-19 was evaluated with a quasi-experimental triple-difference approach using logistic regression.

RESULTS

Among 2 950 147 adults undergoing inpatient surgery (1 550 752 female [52.6%]) at 677 hospitals, the primary payer was Medicare (1 427 791 [48.4%]), followed by commercial insurance (1 000 068 [33.9%]), Medicaid (321 600 [10.9%]), other payer (140 959 [4.8%]), and no insurance (59 729 [2.0%]). Mortality rates increased more for patients undergoing surgery during the first wave of the pandemic in hospitals with a high COVID-19 burden (adjusted odds ratio [AOR], 1.13; 95% CI, 1.03-1.24; P = .01) and a very high COVID-19 burden (AOR, 1.38; 95% CI, 1.24-1.53; P < .001) compared with patients in hospitals with a low COVID-19 burden. Overall, patients with Medicaid had 29% higher odds of death (AOR, 1.29; 95% CI, 1.22-1.36; P < .001) and patients without insurance had 75% higher odds of death (AOR, 1.75; 95% CI, 1.55-1.98; P < .001) compared with patients with commercial insurance. However, mortality rates for surgical patients with Medicaid insurance (AOR, 1.03; 95% CI, 0.82-1.30; P = .79) or without insurance (AOR, 0.85; 95% CI, 0.47-1.54; P = .60) did not increase more than for patients with commercial insurance in hospitals with a high COVID-19 burden compared with hospitals with a low COVID-19 burden. These findings were similar in hospitals with very high COVID-19 burdens.

CONCLUSIONS AND RELEVANCE

In this cross-sectional study, the first wave of the COVID-19 pandemic was associated with a higher risk of mortality after surgery in hospitals with more than 25.0% of patients with COVID-19. However, the pandemic was not associated with greater increases in mortality among patients with no insurance or patients with Medicaid compared with patients with commercial insurance in hospitals with a very high COVID-19 burden.

Low Blood Pressure Threshold for Adverse Outcomes During Left Ventricular Assist Device Support

It has been suggested that maintaining low mean arterial pressure (MAP) in left ventricular assist device (LVAD) recipients is associated with a reduced risk of stroke/death. However, the lower limit of the optimal MAP range has not been established. We aimed to identify this lower limit in a contemporary cohort of LVAD recipients with frequent longitudinal MAP measurements. We analyzed 86,651 MAP measurements in 309 patients with an LVAD (32% LVADs with full magnetic levitation of the impeller) at a tertiary medical center during a mean follow-up of 1.7 ± 1.1 years. Cox proportional hazards regression modeling was used to study the association of serial MAP measurements with stroke/death within 3 years after index discharge. Multivariate analysis identified MAP ≤75 mm Hg, compared with MAP >75 mm Hg, as the low MAP threshold associated with increased risk of death (hazard ratio [HR] 4.74, 95% confidence interval [CI] 2.85 to 7.87, p <0.001), stroke (HR 2.72;, 95% CI 1.39 to 5.33, p = 0.01), and stroke/death (HR 4.45, 95% CI 2.83 to 6.99, p <0.001). The risk associated with MAP ≤75 mm Hg was consistent in subgroups categorized by age, gender, race, device type, renal function, right-sided heart failure, and blood pressure medications. In conclusion, our findings suggest that maintaining MAP ≤75 mm Hg during long-term follow-up in LVAD recipients is associated with increased risk of stroke/death regardless of risk factors or medical management.

Cerebral Blood Flow Hemispheric Asymmetry in Comatose Adults Receiving Extracorporeal Membrane Oxygenation

Peripheral veno-arterial extracorporeal membrane oxygenation (ECMO) artificially oxygenates and circulates blood retrograde from the femoral artery, potentially exposing the brain to asymmetric perfusion. Though ECMO patients frequently experience brain injury, neurologic exams and imaging are difficult to obtain. Diffuse correlation spectroscopy (DCS) non-invasively measures relative cerebral blood flow (rBF) at the bedside using an optical probe on each side of the forehead. In this study we observed interhemispheric rBF differences in response to mean arterial pressure (MAP) changes in adult ECMO recipients. We recruited 13 subjects aged 21–78 years (7 with cardiac arrest, 4 with acute heart failure, and 2 with acute respiratory distress syndrome). They were dichotomized via Glasgow Coma Scale Motor score (GCS-M) into comatose (GCS-M ≤ 4; n = 4) and non-comatose (GCS-M > 4; n = 9) groups. Comatose patients had greater interhemispheric rBF asymmetry (ASYM_rBF) vs. non-comatose patients over a range of MAP values (29 vs. 11%, p = 0.009). ASYM_rBF in comatose patients resolved near a MAP range of 70–80 mmHg, while rBF remained symmetric through a wider MAP range in non-comatose patients. Correlations between post-oxygenator pCO₂ or pH vs. ASYM_rBF were significantly different between comatose and non-comatose groups. Our findings indicate that comatose patients are more likely to have asymmetric cerebral perfusion.

Cause of In-Hospital Death After Weaning from Venoarterial-Extracorporeal Membrane Oxygenation

PURPOSE

A survival gap between weaning from venoarterial-extracorporeal membrane oxygenation (VA-ECMO) and the hospital discharge has been consistently reported. The aim of this study is to investigate the clinical features of patients who underwent successful VA-ECMO decannulation at our institution and to identify the major contributors responsible for adverse outcomes.

METHODS

We retrospectively reviewed all patients supported with VA-ECMO in our institution between January 2013 and June 2020. Only patients that survived VA-ECMO and underwent successful decannulation were included and dichotomized based on survival to hospital discharge: non-survivors versus survivors. The primary study outcome was the cause of death after successful VA-ECMO decannulation.

RESULTS

Of the 262 adult patients who underwent VA-ECMO decannulation, 72 (27.5%) patients did not survive to hospital discharge. Non-survivors were older (62 vs. 54 years, p < 0.001) and suffering from many pre-existing comorbidities. Pneumonia and sepsis were the most frequent infectious complication and almost twice as likely in non-survivors. Major causes of death were: cardiovascular (31.9%), infections (25.0%) and neurological (20.8%). The survival curve demonstrated that 51.4% of our patients died within 8 days after decannulation. Multivariate analysis identified older age, central venous cannulation, pulmonary bleeding and infection, dialysis after VA-ECMO, sepsis, and ischemic stroke (OR = 7.86, 95% CI: 2.76-2.43, p < 0.001) as factors significantly predisposing to patients' death.

CONCLUSION

In our study, one-third of patients decannulated off VA-ECMO did not survive to hospital discharge due to end-stage heart failure, infections or neurological injury. The first 8 post-decannulation days were recognized as a critical period where thorough strategies to prevent acquired infections and cautious support of end-organ function should be warranted. Future large-scale trials are needed to confirm our results.

Long-term survival on LVAD support: Device complications and end-organ dysfunction limit long-term success

BACKGROUND

Preoperative variables can predict short term left ventricular assist device (LVAD) survival, but predictors of extended survival remain insufficiently characterized.

METHOD

Patients undergoing LVAD implant (2012-2018) in the Intermacs registry were grouped according to time on support: short-term (<1 year, n = 7,483), mid-term (MT, 1-3 years, n = 5,976) and long-term (LT, ≥3 years, n = 3,015). Landmarked hazard analyses (adjusted hazard ratio, HR) were performed to identify correlates of survival after 1 and 3 years of support.

RESULTS

After surviving 1 year of support, additional LVAD survival was less likely in older (HR 1.15 per decade), Caucasian (HR 1.22) and unmarried (HR 1.16) patients (p < 0.05). After 3 years of support, only 3 preoperative characteristics (age, race, and history of bypass surgery, p < 0.05) correlated with extended survival. Postoperative events most negatively influenced achieving LT survival. In those alive at 1 year or 3 years, the occurrence of postoperative renal (creatinine HR MT = 1.09; LT HR = 1.10 per mg/dl) and hepatic dysfunction (AST HR MT = 1.29; LT HR = 1.34 per 100 IU), stroke (MT HR = 1.24; LT HR = 1.42), infection (MT HR = 1.13; LT HR = 1.10), and/or device malfunction (MT HR = 1.22; LT HR = 1.46) reduced extended survival (all p ≤ 0.03).

CONCLUSIONS

Success with LVAD therapy hinges on achieving long term survival in more recipients. After 1 year, extended survival is heavily constrained by the occurrence of adverse events and postoperative end-organ dysfunction. The growth of destination therapy intent mandates that future LVAD studies be designed with follow up sufficient for capturing outcomes beyond 24 months.

Effect of a Multidisciplinary Pulmonary Embolism Response Team on Patient Mortality

Multidisciplinary Pulmonary Embolism Response Teams (PERTs) may improve the care of patients with a high risk of pulmonary embolism (PE). The impact of a PERT on long-term mortality has never been evaluated. An observational analysis was conducted of 137 patients before PERT implementation (between 2014 and 2015) and 231 patients after PERT implementation (between 2016 and 2019), presenting to the emergency department of an academic medical center with submassive and massive PE. The primary outcome was 6-month mortality, evaluated by univariate and multivariate analyses. PERT was associated with a sustained reduction in mortality through 6 months (6-month mortality rates of 14% post-PERT vs 24% pre-PERT, unadjusted hazard ratio of 0.57, Relative Risk Reduction of 43%, p = 0.025). There was a reduced length of stay following PERT implementation (9.1 vs 6.5 days, p = 0.007). Time from triage to a diagnosis of PE was independently predictive of mortality, and the risk of mortality was reduced by 5% for each hour earlier that the diagnosis was made. In conclusion, this study is the first to demonstrate an association between PERT implementation and a sustained reduction in 6-month mortality for patients with high-risk PE.

Smoking and the Risk of Stroke in Patients with a Left Ventricular Assist device

There are limited data on the association of smoking with the risk of stroke following left ventricular assist device (LVAD) implantation. We designed this study to analyze the impact of smoking status at the time of LVAD implantation on stroke. We hypothesized that current smokers are at increased risk of stroke when compared with patients who were former or never smokers. The study population comprised of 369 patients in the University of Rochester Medical Center LVAD database, implanted with an LVAD between 2008 and 2018. Patients were stratified as current smoker (smoking within 30 days before LVAD implantation), former smoker, and never smoker. Stroke was defined as a transient ischemic attack or cerebrovascular accident (hemorrhagic or ischemic). There were 45 current smokers, 198 former smokers, and 125 never smokers. Current smokers were younger (mean age 50 ± 11 years), as compared with former (58 ± 12 years) and never smokers (56 ± 13 years) p < 0.001. At 2 years following LVAD implantation, the cumulative incidence of stroke was significantly higher among current smokers (39%) as compared with former and never smokers (16% and 15%, respectively; p = 0.022 for the overall difference during follow-up). In a multivariate model adjusted for significant clinical variables, current smoking was associated with a significant 88% (p = 0.018) higher risk of stroke when compared with all noncurrent smokers. In conclusion, our data suggest that LVAD candidates who are current smokers experience a significantly higher risk of stroke following device implantation.

Using machine learning to improve survival prediction after heart transplantation

BACKGROUND

This study investigates the use of modern machine learning (ML) techniques to improve prediction of survival after orthotopic heart transplantation (OHT).

METHODS

Retrospective study of adult patients undergoing primary, isolated OHT between 2000 and 2019 as identified in the United Network for Organ Sharing (UNOS) registry. The primary outcome was 1-year post-transplant survival. Patients were randomly divided into training (80%) and validation (20%) sets. Dimensionality reduction and data re-sampling were employed during training. Multiple machine learning algorithms were combined into a final ensemble ML model. The discriminatory capability was assessed using the area under receiver-operating-characteristic curve (AUROC), net reclassification index (NRI), and decision curve analysis (DCA).

RESULTS

A total of 33,657 OHT patients were evaluated. One-year mortality was 11% (n = 3738). In the validation cohort, the AUROC of singular logistic regression was 0.649 (95% CI, 0.628-0.670) compared to 0.691 (95% CI, 0.671-0.711) with random forest, 0.691 (95% CI, 0.671-0.712) with deep neural network, and 0.653 (95% CI, 0.632-0.674) with Adaboost. A final ensemble ML model was created that demonstrated the greatest improvement in AUROC: 0.764 (95% CI, 0.745-0.782) (p < .001). The ensemble ML model improved predictive performance by 72.9% ±3.8% (p < .001) as assessed by NRI compared to logistic regression. DCA showed the final ensemble method improved risk prediction across the entire spectrum of predicted risk as compared to all other models (p < .001).

CONCLUSIONS

Modern ML techniques can improve risk prediction in OHT compared to traditional approaches. This may have important implications in patient selection, programmatic evaluation, allocation policy, and patient counseling and prognostication.

Study results suggest less invasive HeartMate 3 implantation is a safe and effective approach for obese patients

BACKGROUND

Historically, obesity was considered a relative contraindication to left ventricular assist device (LVAD) implantation with less invasive surgery (LIS). The present study aimed to compare the outcomes of obese patients who underwent LVAD implantation through LIS with those who received full sternotomy (FS) implantation.

METHODS

We retrospectively reviewed all patients implanted with HeartMate 3 LVAD in our institution between September 2015 and June 2020. Obese patients (BMI ≥ 30 kg/m²) were included and dichotomized based on surgical approach into the FS or LIS cohort.

RESULTS

Of 231 implanted patients, 107 (46%) were obese and included in the study. FS was performed in 26 (24%) patients and LIS approach in 81 (76%) patients. Preoperative patient characteristics were similar between the cohorts. Postoperatively, patients in LIS cohort had less bleeding (p = 0.029), fewer transfusions (p = 0.042), shorter duration of inotropic support (p = 0.049), and decreased incidence of severe RV failure (11.1% vs 30.8%, p = 0.028). Survival to discharge for the obese population was 87.5% overall and did not differ based on an approach (91.4% LIS vs 76.9% FS, p = 0.079). More LIS patients were discharged home (60.0% vs 82.4%, p = 0.041) rather than to rehabilitation center.

CONCLUSION

Our results showed that the LIS approach in obese patients is associated with fewer postoperative complications and a trend towards better short-term survival. These results suggest that less invasive LVAD implantation is a safe and effective approach for obese patients. Future prospective randomized trials are required to substantiate these results.

Enhanced Recovery After Surgery in Patients Implanted with Left Ventricular Assist Device

INTRODUCTION

We sought to develop and implement a comprehensive enhanced recovery after surgery (ERAS) protocol for patients implanted with a left ventricular assist device (LVAD).

METHODS AND RESULTS

In this article, we describe our approach to the development and phased implementation of the protocol. Additionally, we reviewed prospectively collected data for patients who underwent LVAD implantation at our institution from February 2019 to August 2020. To compare early outcomes in our patients before and after protocol implementation, we dichotomized patients into two 6-month cohorts (the pre-ERAS and ERAS cohorts) separated from each other by 6 months to allow for staff adoption of the protocol. Of the 115 LVAD implants, 38 patients were implanted in the pre-ERAS period and 46 patients in the ERAS period. Preoperatively, the patients` characteristics were similar between the cohorts. Postoperatively, we observed a decrease in bleeding (chest tube output of 1006 vs 647.5 mL, P < .001) and blood transfusions (fresh frozen plasma 31.6% vs 6.7%, P = .04; platelets 42.1% vs 8.7%, P = .001). Opioid prescription at discharge were 5-fold lower with the ERAS approach (P < .01). Furthermore, the number of patients discharged to a rehabilitation facility decreased significantly (20.0% vs 2.4%, P = .02). The index hospitalization length of stay and survival were similar between the groups.

CONCLUSIONS

ERAS for patients undergoing LVAD implantation is a novel, evidence-based, interdisciplinary approach to care with multiple potential benefits. In this article, we describe the details of the protocol and early positive changes in clinical outcomes. Further studies are needed to evaluate benefits of an ERAS protocol in an LVAD population.Lay Summary: Enhanced recovery after surgery (ERAS) is the implementation of standardized clinical pathways that ensures the use of best practices and decreased variation in perioperative care. Multidisciplinary teams work together on ERAS, thereby enhancing communication among health care silos. ERAS has been used for more than 30 years by other surgical services and has been shown to lead to a decreased length of stay, fewer complications, lower mortality, fewer readmissions, greater job satisfaction, and lower costs. Our goal was to translate these benefits to the perioperative care of complex patients with a left ventricular assist device. Early results suggest that this goal is possible; we have observed a decrease in transfusions, discharge on opioids, and discharge to a rehabilitation facility.

Minimally invasive off-pump surgical pulmonary embolectomy for improved patient-centred care

We present a complicated case of massive pulmonary embolism occurring 11 weeks after a craniotomy in a patient with multiple high-risk comorbidities. The patient underwent successful pulmonary artery surgical embolectomy via left mini-thoracotomy incision on peripheral venoarterial extracorporeal membrane oxygenation support. For this patient, avoiding a sternotomy allowed for greatly decreased postoperative morbidity and the use of venoarterial extracorporeal membrane oxygenation allowed for the avoidance of intraoperative anticoagulation. This case demonstrates the feasibility of off-pump surgical pulmonary embolectomy via left mini-thoracotomy as a treatment strategy for appropriate patients to improve patient-centred care.

Complete sternal-sparing left ventricular assist device implantation is associated with improved postoperative mobility

Left ventricular assist device (LVAD) implantation via a complete sternal-sparing (CSS) technique is gaining interest due to several potential benefits. We hypothesized that the CSS approach for HeartMate 3 (HM3) LVAD implantation improves postoperative mobility and physical independence compared to full sternotomy (FS). We retrospectively reviewed patients who were implanted with a commercial HM3 at our institution from September 2017 to August 2018. The Activity Measure for Post-Acute Care short forms and Functional Independence Measure scores were used to assess the patient's physical limitations postoperatively. A total of 43 patients were included in the study: 27 (63%) CSS patients and 16 (37%) FS patients. At postoperative day 3, the CSS cohort demonstrated improved mobility based on Activity Measure for Post-Acute Care scores compared to the FS group; 40% of the CSS cohort versus 67% of the FS cohort remained 100% impaired. The CSS cohort also demonstrated greater postoperative independence in the Functional Independence Measure sit-to-stand metric with 78% of the CSS cohort achieving modified or complete independence by postoperative day 15 compared to only 21% of the FS patients. These early data suggest that the CSS approach for HM3 LVAD implantation improves postoperative mobility and functional independence compared to FS.

Long-term renal function after venoarterial extracorporeal membrane oxygenation

BACKGROUND

The utilization of venoarterial extracorporeal membrane oxygenation (VA-ECMO) as a life-supporting therapy has increased exponentially over the last decade. As more patients receive and survive ECMO, there are a number of unanswered clinical questions about their long-term prognosis and organ function including the need for long-term dialysis.

METHODS

We aimed to utilize over 208 patient-years of follow-up data from our large institutional cohort of VA-ECMO patients to determine the incidence of requiring VA-ECMO support on the need for renal replacement therapy after discharge (LT-dialysis). This retrospective review included all adult VA-ECMO patients at our institution from January 2014 to October 2018 (N = 283).

RESULTS

Out of the 99 (35%) survivors, 88 (89%) did not require LT-dialysis of any duration after discharge from the index hospitalization. Patients who required VA-ECMO for decompensated cardiogenic shock were more likely to need LT-dialysis (p = .034), and those who required renal replacement therapy during VA-ECMO (N = 27) also had a higher incidence of LT-dialysis (33%).

CONCLUSION

Overall, these data suggest there is a low incidence of long-term dialysis dependence among survivors of VA-ECMO support. Worries about the potential long-term detrimental effect of VA-ECMO should not preclude patients from receiving this life-saving support.

Patient-Reported Outcomes Measurement Information System (PROMIS) in Left Ventricular Assist Devices

BACKGROUND

Appropriate collection of quality of life (QOL) measurements for left ventricular assist device (LVAD) patients is challenging. Patient-Reported Outcomes Measurement Information System (PROMIS) is a popular tool that has been validated across multiple disciplines, but its applicability to the LVAD population remains unknown.

METHODS

This single-center, retrospective review included LVAD patients that completed a PROMIS assessment and Kansas City Cardiomyopathy Questionnaire (KCCQ-12) survey at clinical encounters postoperatively. Patients completed computer adaptive PROMIS assessments for physical function, pain interference and depression. All PROMIS domains are designed to follow a normal distribution (mean T-score 50, standard deviation 10) in the general population. Assessments were aggregated over time and correlation between the KCCQ-12 summary score and each PROMIS domain was assessed individually.

RESULTS

A total of 178 LVAD patients were included in the study. The median time between LVAD implantation and PRO collection was 16.5 [interquartile range, 7.9-37.8] months. Patients typically had worse physical function (T-score 38.8 [33.6-44.2]) but comparable pain (51.1 [38.7-59.2]) and depression (49.9 [41.7-57.5]) as the general population. The KCCQ-12 was more strongly correlated to PROMIS physical function (Spearman's ρ = 0.746) than pain (ρ = -0.539) or depression (ρ = -0.591).

CONCLUSIONS

PROMIS provides a robust QOL data collection system that can be implemented in a clinical setting without imposing a significant burden. Using this more holistic system may allow for better patient-centered care in order to address QOL limitations imposed by LVAD support that are not directly related to heart failure symptoms.

Transcatheter aortic valve replacement in left ventricular assist device patient-overcoming the complications with transapical approach and circulatory arrest

We present the patient with severe aortic insufficiency (AI) 5 years post left ventricular assist device (LVAD) implantation. His management was complicated with unsuccessful percutaneous aortic valve closure attempt, transcatheter aortic valve replacement (TAVR) implantation with a severe paravalvular leak, eventual valve dislodgment into the left ventricle (LV), and LVAD inflow cannula occlusion. We utilized a mini-thoracotomy approach to successfully retrieve the dislodged valve through the LV apex while deploying a valve-in-valve TAVR under direct visualization and deep hypothermic cardiac arrest. This case can serve as an example of the serious pitfalls and potential resolution strategies when treating LVAD-associated AI.

The use of hydroxocobalamin for vasoplegic syndrome in left ventricular assist device patients

We demonstrate evidence supporting the efficacy of hydroxocobalamin in reducing vasopressor requirements for LVAD patients with refractory vasoplegia. Further study is needed to substantiate these findings and determine its optimal use in practice.

Long-term milrinone therapy as a bridge to heart transplantation: Safety, efficacy, and predictors of failure

BACKGROUND

Studies of long-term inotrope use in advanced HF have previously provided limited and conflicting results. This study aimed to evaluate the safety and efficacy of long-term milrinone use and identify predictors of failure to bridge to orthotropic heart transplant (OHT) in a cohort of end-stage heart failure (HF) patients listed for heart transplantation and receiving inotrope therapy.

METHODS

The study included 150 adults listed for OHT at a single center from 2001 to 2017 who received milrinone therapy for ≥30 days. Multivariate Cox proportional hazards models were used to identify factors associated with "failure" (left ventricular assist device, intra-aortic balloon pump, status downgrade due to instability, death) vs. "success" (OHT, recovery) during bridging to OHT.

RESULTS

"Failure" occurred in 33 (22%) patients. Factors independently associated with failure included male sex (HR = 7.6; p = 0.004), no implantable cardioverter-defibrillator (HR = 3.8; p = 0.009), and lack of guideline-directed medical therapy (GDMT) with a beta-blocker (HR = 7.8; p = 0.002) or angiotensin-converting enzyme inhibitor/angiotensin receptor blocker (HR = 6.3; p < 0.001). Patients who received fewer guideline-directed medications had a higher cumulative probability of failure. Adverse events included central line-associated bloodstream infection (2.55 per 1000 line-days) and arrhythmia (1.59 per 1000 treatment-days).

CONCLUSIONS

Our findings suggest that long-term milrinone therapy in selected patients is associated with a high rate of successful bridging to OHT and a low rate of adverse events. Patients intolerant of GDMT are more likely to fail to bridge to OHT without mechanical support. Sex differences in outcomes associated with milrinone therapy should be explored.

Association of previous cardiac surgery with outcomes in left ventricular assist device patients

OBJECTIVES

History of prior cardiac surgery has traditionally been considered a risk factor for subsequent cardiac procedures. The aim of this study was to investigate the outcomes of patients implanted with a left ventricular assist device via redo sternotomy.

METHODS

Prospectively collected data were reviewed for all patients implanted with a continuous-flow left ventricular assist device at a single institution from December 2006 through June 2018. Patients were separated into 2 cohorts: those with a history of prior cardiac surgery (redo sternotomy) and those undergoing primary sternotomy at the time of left ventricular assist device implantation. The primary outcome was overall survival.

RESULTS

Of the 321 patients included in the study, 77 (24%) were implanted via redo sternotomy and 244 (76%) via primary sternotomy. The redo sternotomy cohort was generally older (59 ± 10 vs 57 ± 12 years, P = 0.050) and had a higher incidence of ischaemic disease (70% vs 49%, P = 0.002). The Kaplan-Meier survival analysis demonstrated that overall survival was not significantly different between the redo sternotomy and primary sternotomy groups (6-month survival: 86% vs 92%; 5-year survival: 53% vs 51%; log-rank P = 0.590 for overall difference during follow-up). The propensity score analysis consistently showed that redo sternotomy was not significantly associated with mortality risk (hazard ratio 1.19, 95% confidence interval 0.73-1.93; P = 0.488). Redo sternotomy patients were more likely to require rehospitalization during their first year postoperatively (P = 0.020) and spent less time out of the hospital during the first year (P = 0.046).

CONCLUSIONS

The redo sternotomy cohort represents a more technically challenging patient population, but overall survival similar to that of primary sternotomy patients can be achieved.

Surgical Pulmonary Embolectomy With No Systemic Anticoagulation for Patient With Recent Stroke

We present the successful use of surgical embolectomy (SE) without systemic anticoagulation to treat a complicated case of pulmonary embolism. The patient presented with an embolic cerebrovascular accident and subsequently developed a massive pulmonary embolism. Because of the risk of hemorrhagic transformation, the decision was made to proceed with emergent SE on venoarterial extracorporeal membrane oxygenation support without anticoagulation. The surgery was performed without complication. The potential to perform SE without anticoagulation could potentially decrease the incidence of surgical bleeding and make SE a therapeutic option for patients with contraindications to anticoagulation. Further research is needed to substantiate the efficacy of this treatment strategy.