Advanced Respiratory Support Days as a Novel Marker of Mortality in COVID-19 Acute Respiratory Distress Syndrome Requiring Extracorporeal Membrane Oxygenation

Emerging evidence suggests prolonged use of noninvasive respiratory support may increase mortality of patients with coronavirus disease 2019 (COVID-19)-associated acute respiratory distress syndrome who require extracorporeal membrane oxygenation (ECMO). Using a database of adults receiving ECMO for COVID-19, we calculated survival curves and multivariable Cox regression to determine the risk of death associated with pre-ECMO use of high-flow nasal oxygen (HFNO), noninvasive ventilation (NIV), and invasive mechanical ventilation (IMV) days. We investigated the performance of a novel variable, advanced respiratory support days (composite of HFNO, NIV, and IMV days), on Respiratory ECMO Survival Prediction (RESP) score. Subjects (N = 146) with increasing advanced respiratory support days (<5, 5-9, and ≥10) had a stepwise increase in 90 day mortality (32.2%, 57.7%, and 75.4%, respectively; p = 0.002). Ninety-day mortality was significantly higher in subjects (N = 121) receiving NIV >4 days (81.8% vs. 52.4%, p < 0.001). Each additional pre-ECMO advanced respiratory support day increased the odds of right ventricular failure (odds ratio [OR]: 1.066, 95% confidence interval [CI]: 1.002-1.135) and in-hospital mortality (1.17, 95% CI: 1.08-1.27). Substituting advanced respiratory support days for IMV days improved RESP score mortality prediction (area under the curve (AUC) or: 0.64 vs. 0.71). Pre-ECMO advanced respiratory support days were associated with increased 90 day mortality compared with IMV days alone. Adjusting the RESP score for advanced respiratory support days improved mortality prediction.

Escalating Surgical Treatment for Left Ventricular Assist Device Infection and Expected Mortality: Clinical Risk Prediction Score

BACKGROUND

Left ventricular assist devices (LVAD) improve survival for patients with cardiac failure, but LVAD specific infections (VSI) remain a challenge with poorly understood predictive risk factors. Furthermore, the indications and utility of escalating medical treatment to surgical debridement and potential flap reconstruction are not well-characterized.

STUDY DESIGN

A retrospective review of consecutive patients undergoing primary LVAD implantation at a tertiary academic center was performed. The primary outcomes measures were 90-day and overall mortality after VSI. Cox proportional hazards regression was used to generate a risk-prediction score for mortality.

RESULTS

Of the 760 patients undergoing primary LVAD implantation, 255 (34%) developed VSI; of these 91 (36%) were managed medically, 134 (52%) with surgical debridement, and 30 (12%) with surgical debridement and flap reconstruction. One-year survival after infection was 85% with median survival of 2.40 years. Factors independently associated with increased mortality were diabetes (hazard ratio (HR) 1.44, p=0.04), methicillin-resistant Staphylococcus aureus infection (HR 1.64, p=0.03), deep space (pump pocket/outflow cannula) involvement (HR 2.26, p<0.001) and extra-corporeal membrane oxygenation after LVAD (HR 2.52, p<0.01. Factors independently associated with decreased mortality were flap reconstruction (HR 0.49, p=0.02) and methicillin-sensitive Staphylococcus aureus infection (HR 0.63, p=0.03). A clinical risk prediction score was developed using these factors and showed significant differences in median survival, which was 5.67 years for low-risk (score 0-1), 3.62 years for intermediate-risk (score 2), and 1.48 years for high-risk (score >3) (p<0.001) patients.

CONCLUSIONS

We developed a clinical risk prediction score to stratify VSI patients. In selected cases, escalating surgical treatment was associated with increased survival. Future work is needed to determine if early surgical debridement and flap reconstruction can alter outcomes in select cases of VSI.

Physiologic benefits of veno-pulmonary extracorporeal membrane oxygenation for COVID-19 ARDS: A single center experience

BACKGROUND

A subset of patients with COVID-19 acute respiratory distress syndrome (ARDS) require extracorporeal membrane oxygenation (ECMO). Veno-pulmonary (VP) ECMO provides support to the right ventricle and decreased risk of recirculation.

METHODS

A retrospective analysis of patients with COVID-19 ARDS and VP ECMO was performed. Patients were separated into groups by indication (1) "right ventricular (RV) failure," (2) "refractory hypoxemia," and (3) "recurrent suck-down events (SDEs)." Pre- and post-configuration vasoactive inotropic scores (VIS), fraction of inspired oxygen (FIO2), and resolution of SDEs were reported. A 90-day mortality was computed for all groups. Patients were also compared to those who underwent conventional venovenous (VV) ECMO.

RESULTS

Forty-seven patients underwent VP ECMO configuration, 18 in group 1, 16 in group 2, and 8 in group 3. Ninety-day mortality was 66% for the entire cohort and was 77.8%, 81.3% and 37.5% for groups 1, 2, and 3, respectively. Mean VIS decreased in group 1 (8.3 vs 2.9, p = 0.005), while mean FIO2 decreased in the group 2 and was sustained at 72 h (82.5% vs 52.5% and 47.5%, p < 0.001). Six of the eight (75%) of patients with recurrent SDEs had resolution of these events after configuration to VP ECMO. Patients with VP ECMO spent more days on ECMO (33 days compared to 18 days, p = 0.004) with no difference in mortality (66% compared to 55.1%, p = 0.28).

CONCLUSION

VP ECMO in COVID-19 ARDS improves hemodynamics in patients with RV failure, improves oxygenation in patients with refractory hypoxemia and improves the frequency of SDEs.

Surgically implanted endovascular, microaxial left ventricular assist device: A single institution study

Objective

The Impella 5.5 (Abiomed, Inc), a surgically implanted endovascular microaxial left ventricular assist device, is increasingly used worldwide and there have been more than 10,000 implants. The purpose of this study is to describe a large-volume, single-center experience with the use of the Impella 5.5.

Methods

Data were obtained retrospectively from patients supported with the Impella 5.5 implanted at our institution from May 1, 2020, to December 31, 2022. Demographic, operative, and postoperative outcomes for each group are described. Results are reported in median (interquartile range) or n (%). The entire cohort was divided into 5 main groups based on the intention to treat at the time of the Impella 5.5 implantation: (1) patients who had a planned Impella 5.5 implanted at the time of high-risk cardiac surgery; (2) patients with cardiogenic shock; (3) patients bridged to a durable left ventricular assist device; (4) patients bridged to transplant; and (5) patients with postcardiotomy shock who received an unplanned Impella 5.5 implant.

Results

A total of 126 patients were supported with the Impella 5.5. Overall survival to device explant was 76.2%, with 67.5% surviving to discharge. Midterm survival was assessed with a median follow-up time of 318 days and demonstrated an overall survival of 60.3% and a median of 650 days (549-752).

Conclusions

Outcomes after using the Impella 5.5 are variable depending on the indication of use. Patient selection may be of utmost importance and requires further experience with this device to determine who will benefit from insertion.

Characterization of de novo malignancy after orthotopic heart transplantation: single-centre outcomes over 20 years

OBJECTIVES

Malignancy is the leading cause of late mortality after orthotopic heart transplantation (OHT), and the burden of post-transplantation cancer is expected to rise in proportion to increased case volume following the 2018 heart allocation score change. In this report, we evaluated factors associated with de novo malignancy after OHT with a focus on skin and solid organ cancers.

METHODS

Patients who underwent OHT at our institution between 1999 and 2018 were retrospectively reviewed (n = 488). Terminal outcomes of death and development of skin and/or solid organ malignancy were assessed as competing risks. Fine-Gray subdistribution hazards regression was used to evaluate the association between perioperative patient and donor characteristics and late-term malignancy outcomes.

RESULTS

By 1, 5 and 10 years, an estimated 2%, 17% and 27% of patients developed skin malignancy, while 1%, 5% and 12% of patients developed solid organ malignancy. On multivariable Fine-Gray regression, age [1.05 (1.03-1.08); P < 0.001], government payer insurance [1.77 (1.20-2.59); P = 0.006], family history of malignancy [1.66 (1.15-2.38); P = 0.007] and metformin use [1.73 (1.15-2.59); P = 0.008] were associated with increased risk of melanoma and basal or squamous cell carcinoma. Age [1.08 (1.04-1.12); P < 0.001] and family history of malignancy [2.55 (1.43-4.56); P = 0.002] were associated with an increased risk of solid organ cancer, most commonly prostate and lung cancer.

CONCLUSIONS

Vigilant cancer and immunosuppression surveillance is warranted in OHT recipients at late-term follow-up. The cumulative incidence of skin and solid organ malignancies increases temporally after transplantation, and key risk factors for the development of post-OHT malignancy warrant identification and routine monitoring.

Management of severe tricuspid valve regurgitation due to ruptured papillary muscle in a patient with mediastinitis early after heart transplant

Objective

Even though severe tricuspid regurgitation is not uncommon after cardiac transplantation, primary severe tricuspid regurgitation is rare. We present such a case with additional complexities.

Methods

The patient was 44-year-old man with a HeartWare durable left ventricular assist device (Heartware Inc) who received a temporary right ventricular assist device (RVAD) with a ProtekDuo cannula (LivaNova Inc USA) for refractory ventricular fibrillation and underwent a heart transplant as United Network for Organ Sharing Status 1, in the presence of partially compensated cardiogenic shock, renal failure. Given complex re-operative surgery in a volume-overloaded patient with unknown pulmonary vascular resistance, an RVAD cannula was preserved and re- inserted during cardiac transplant. Postoperatively he required hemodialysis, had severe primary tricuspid regurgitation discovered after RVAD removal and developed Enterobacter mediastinitis. He underwent complex tricuspid valve repair for flail tricuspid leaflet due to ruptured papillary muscle likely due to RVAD cannula injury, after multiple mediastinal washouts and was followed by delayed chest reconstruction.

Results

The patient is doing well, 6 months after discharge to home, asymptomatic, without re-admissions, on renal recovery path, with no tricuspid regurgitation and good biventricular function.

Conclusions

Replacing the tricuspid valve in presence of hemodialysis catheter, immunosuppression and mediastinitis could be high risk for endocarditis. Even though we have short-term follow-up, tricuspid valve repair can be an effective way of managing primary severe regurgitation especially when there is a desire or need to avoid valve replacement.

Circulatory Arrest for Traumatic Brachiocephalic Artery Pseudoaneurysm Repair

Blunt traumatic injuries to the brachiocephalic artery require surgical management. The operative technique used depends on the location of the injury, the patient's hemodynamic stability, and the surgeon's experience. Perfusion strategy can facilitate vascular control of the aortic arch and branch vessels. This report presents an urgent repair of a proximal posterior blunt traumatic brachiocephalic artery injury under circulatory arrest, with an excellent outcome.

Competing Risks to Transplant in Bridging with Continuous Flow Left Ventricular Assist Devices

BACKGROUND

Continuous flow left ventricular assist device(CF-LVAD) support is a mainstay in the hemodynamic management of patients with end-stage heart failure refractory to optimal medical therapy. In this report, we evaluated waitlist complications and competing outcomes for CF-LVAD patients compared to primary transplant candidates listed for orthotopic heart transplantation(OHT) at a single center.

METHODS

All patients listed for OHT between 2006-2020 at our institution were retrospectively reviewed(n=300 CF-LVAD; n=244 primary transplant). Kaplan-Meier methodology with log-rank testing was used to evaluate survival outcomes. Terminal outcomes of death, delisting, and transplant were assessed as competing risks and compared between groups using Gray's test. Multivariable Fine-Gray regression was used to identify predictors of transplantation.

RESULTS

One-year rates of transplant, delisting, and death were 48%, 8%, and 2%, respectively for CF-LVAD patients and 45%, 15%, and 9% for primary transplant(all P<0.001). Waitlist mortality at 5 years was 4% among CF-LVAD patients and 13% for primary transplants. All-cause mortality after listing was lower for CF-LVAD patients(P=0.017). There was no difference in post-transplant survival between groups(P=0.250). On multivariable Fine-Gray regression, stroke(P=0.017), respiratory failure(P=0.032), right ventricular failure(P=0.019), and driveline infection(P=0.050) were associated with decreased probability of transplantation. Post-transplant survival was not significantly worse for CF-LVAD patients who experienced device-related complications(P=0.901).

CONCLUSIONS

While device related-complications were significantly associated with decreased rates of transplant, CF-LVAD patients had excellent waitlist outcomes overall. In light of the 2018 allocation score change, the risk of complications should be taken into account when deciding whether to offer CF-LVAD as a bridge to transplant.

30 Years of Heart Transplant: Outcomes after Mechanical Circulatory Support from a Single Center

BACKGROUND

Survival after bridge to transplant with mechanical circulatory support (MCS) has yielded varying outcomes based on device type and baseline characteristics Continuous flow left ventricular assist devices (CF-LVADs) have significantly improved waitlist mortality, but recent changes to the transplant listing criteria have dramatically altered the use of MCS for bridge to transplant.

METHODS

Orthotopic heart transplants from 1988-2019 at our institution were retrospectively reviewed and stratified by pre-transplant MCS status into CF-LVAD (n=224), Pulsatile LVAD (n=49), temporary MCS (n=71), and primary transplant (n=463) groups. Patients transplanted after the approval of CF-LVAD for bridge to transplant and before the 2018 allocation policy changes underwent subgroup analysis to evaluate predictors of survival and complications in a contemporary cohort.

RESULTS

Rates of primary transplant declined from 88% to 14% over the course of the study. No significant difference in survival was detected in the cohort stratified by MCS status (P=0.18). In the modern era, survival for CF-LVAD and temporary MCS patients was non-inferior to primary transplant (P=0.22). Notable predictors of long-term mortality included lower body mass index, peripheral vascular disease, prior coronary artery bypass graft, ABO non-identical transplant, and increased donor age (all P<0.02). There were no differences in major postoperative complications.

CONCLUSIONS

CF-LVAD has grown to account for the majority of transplants at our center in the last decade with no adverse effect on survival or postoperative complications. Temporary MCS has increased following the 2018 listing criteria change with acceptable early outcomes.

Cannulation Strategy for Extracorporeal Membrane Oxygenation Does Not Influence Total Hospital Cost

BACKGROUND

Center for Medicare Services decreased reimbursement rates for peripheral veno-arterial (VA ECMO) and veno-venous (VV ECMO) extracorporeal membrane oxygenation procedures in October 2018. Limited data are available describing hospital costs and clinical resources required to support ECMO patients.

METHODS

All patients supported on ECMO at our institution between March 2017 and October 2018 were identified. Exclusion criteria were cannulation at referring hospitals, organ transplant recipients, and temporary right ventricular support. The cohort was stratified by initial cannulation strategy. Outcomes were total hospital cost and clinical resource utilization.

RESULTS

29 patients were supported on central VA, 72 on peripheral VA, and 37 on VV ECMO. Thirty-day survival was 48% for central vs 37% for peripheral vs 51% for VV. Hospital costs were $187,848 for central vs $178,069 for peripheral vs $172,994 for VV, P=0.91. Mean hospital stay was 25.8 days for central vs 21.5 for peripheral vs 26.2 for VV, P=0.49. Mean intensive care unit stay was 14.1 days for central vs 12.8 for peripheral vs 7.7 for VV, P=0.25. Mean length of ECMO support was 6.5 days for central vs 6.2 for peripheral vs 7.8 for VV, P=0.38. Mean ventilator time was 13.0 days for central vs 8.2 for peripheral vs 10.0 for VV P=0.06. Hemodialysis was utilized in 41% central, 47% peripheral, and 41% VV patients, P=0.75. Theoretical ECMO reimbursement losses ranged from $1,970,698 to $5,648,219 annually under 2018 Center for Medicare Services rates.

CONCLUSIONS

ECMO cannulation strategy has minimal impact on resource utilization and hospital cost.

Cardiac allograft rejection in the current era of continuous flow left ventricular assist devices

OBJECTIVE

Left ventricular assist device (LVAD) implantation has been shown to increase allosensitization before orthotopic heart transplantation, but the influence of LVAD support on posttransplant rejection is controversial. This study examines the postoperative incidence of acute cellular rejection (ACR) in patients bridged with continuous flow LVAD (CF-LVAD) relative to primary transplant (Primary Tx).

METHODS

All patients who underwent orthotopic heart transplantation at our institution between July 2006 and March 2019 were retrospectively reviewed (n = 395). Patients were classified into Primary Tx (n = 145) and CF-LVAD (n = 207) groups. Propensity score matching on 13 covariates implemented a 0.1 caliper logistic model with nearest neighbor 1:1 matching. Development of moderate to severe (ie, 2R/3R) rejection was evaluated using a competing risks model. Potential predictors of 2R/3R ACR were evaluated using Fine-Gray regression on the marginal subdistribution hazard.

RESULTS

Propensity score matching yielded 122 patients in each group (n = 244). At 12 and 24 months, the cumulative incidence of 2R/3R ACR was 17% and 23% for the CF-LVAD group and 26% and 31%, respectively, for the Primary Tx group (P = .170). CF-LVAD was not predictive of 2R/3R rejection on multivariable Fine-Gray regression (subdistribution hazard ratio, 0.73; 95% confidence interval, 0.40-1.33; P = .301). There was no difference in the 5-year incidence of antibody mediated rejection (10% [n = 12] vs 9% [n = 11]; P = .827).

CONCLUSIONS

After adjusting for covariates, CF-LVAD was not associated with an increased risk of moderate to severe ACR during the 24 months after cardiac transplantation. Further investigation is warranted with larger cohorts, but CF-LVAD may have minimal influence on posttransplant ACR.

Impact of Surgical Experience on Operative Mortality After Reoperative Cardiac Surgery

BACKGROUND

Learning curves and skill attrition with aging have been reported to impair outcomes in select surgical subspecialties, but their role in complex cardiac surgery remains unknown.

METHODS

From 1986 to 2019, 2314 patients underwent reoperative cardiac surgery: coronary artery bypass grafting (n = 543), valve (n = 1527), or combined coronary artery bypass grafting and valve (n = 244). Thirty-four different surgeons in practice between 1 and 39 years were included. Standardized mortality ratio (observed-to-expected) was determined for all surgeons in each post-training year of experience.

RESULTS

Risk-adjusted cumulative sum change-point analysis was used to define five distinct career phases: 0 to 4 years, 5 to 8 years, 9 to 17 years, 18 to 28 years, and 29 to 39 years. With 5 to 8 years and 18 to 28 years of experience, standardized mortality ratio was near unity (0.95 and 1.05, respectively) and lowest with 9 to 17 years of experience (0.78, P = .03). In the youngest experience group (0 to 4 years), observed and expected mortality were both highest, and standardized mortality ratio was elevated at 1.29, which approached statistical significance (P = .059). In the oldest experience group (29 to 39 years), expected mortality was low compared with most other groups but observed mortality increased, yielding a significantly elevated standardized mortality ratio at 1.53 (P = .032).

CONCLUSIONS

Standardized mortality ratios with reoperative cardiac surgery were highest early and late in a surgeon's career and lowest in mid career. As surgeons gain experience, outcomes improve through the first two career decades, then stabilize in the third decade before declining in the fourth decade.

Hypertrophic obstructive cardiomyopathy: the Mayo Clinic experience

BACKGROUND

Hypertrophic cardiomyopathy (HCM) is a primary myocardial disease characterized by left ventricular hypertrophy in the absence of other etiologies. Clinical presentation may vary from asymptomatic to sudden cardiac death. Medical treatment is the first-line therapy for symptomatic patients. Extended left ventricular septal myectomy is the procedure of choice if medical treatment is unsuccessful or intolerable.

MAYO CLINIC EXPERIENCE

More than 3,000 patients have had septal myectomy for HCM at the Mayo Clinic (MN, USA) from 1993 to 2016. Risk of hospital death after isolated septal myectomy for obstructive HCM is <1% and is similar to the risk of operation for elective mitral valve repair. Complications, such as complete heart block requiring permanent pacemaker, are uncommon (2%), although partial or complete left bundle branch block is a frequent finding on the postoperative ECG. Relief of left ventricular outflow tract (LVOT) obstruction with septal myectomy dramatically improves symptoms and exercise capacity in symptomatic patients with obstructive HCM. More than 90% of severely symptomatic patients have improvement by at least two functional classes, and reduction of outflow gradients by myectomy decreases or eliminates symptoms of dyspnea, angina and/or syncope. Basal obstruction with systolic anterior motion (SAM) is treated by transaortic myectomy. The transapical approach was applied in 115 patients with obstructive midventricular and apical variants of HCM between 1993 and 2012. All patients with midventricular obstruction had gradient relief and none developed an apical aneurysm or ventricular septal defect. Recurrent obstruction after satisfactory myectomy was rare.

CONCLUSIONS

Septal myectomy effectively and definitively relieves LVOT obstruction and cardiac symptoms in patients with obstructive HCM. In experienced centers, early mortality for isolated septal myectomy is less than 1%, and overall results are excellent and continue to improve in the current era.

Right Coronary Artery Septic Embolization Secondary to Aerococcus urinae Native Mitral Valve Endocarditis

Septic embolization to the coronary arteries from infective endocarditis is a rare occurrence. Appropriate treatment is not yet fully determined. We report a case of mitral valve endocarditis due to Aerococcus urinae presenting as acute inferior myocardial infarction.

Libman-Sacks Endocarditis in a Patient With Antiphospholipid Syndrome

Antiphospholipid syndrome is a systemic autoimmune syndrome with cardiac manifestations such as nonbacterial thrombotic endocarditis, also known as Libman-Sacks endocarditis. A 61-year-old female with history of antiphospholipid syndrome presented in acute pulmonary edema. Echocardiography demonstrated mobile vegetations on the free margins of both the anterior and the posterior mitral valve leaflets. Blood cultures and fungal serologies were negative. During mitral valve replacement both the anterior and posterior mitral leaflets were covered with multiple small vegetations with features of nonbacterial thrombotic endocarditis. Though mostly asymptomatic, Libman-Sacks endocarditis may be an indication for valve replacement.

Acute superior vena cava obstruction due to tight pericardial closure following congenital defect repair

The obstruction of the superior vena cava (SVC) of acute onset nature following surgery is a rare and serious condition. The tight closure of the pericardium over the heart during surgical procedures may cause external compression on the SVC. Echocardiography and Computed tomography (CT) scan aids in the diagnosis. Cutting open the pericardial stitches relieves the condition.

Tunneling technique for anatomical positioning of aortoaxillary bypass graft

A technique for anatomical positioning of a synthetic aortoaxillary bypass tube graft is described. A tunnel is created with the help of a Roberts clamp and intercostal tube drain. There is no need to open the pleura because the graft is tunneled parallel to the subclavian vessels outside the chest cavity.