Unmasking obstruction in hypertrophic cardiomyopathy with postprandial resting and treadmill stress echocardiography.

BACKGROUND: Latent left ventricular outflow tract obstruction (LVOTO) is an important cause of symptoms in patients with hypertrophic cardiomyopathy (HCM) but can be challenging to provoke. OBJECTIVES AND METHODS: To examine the value of postprandial resting and stress echocardiography and utilization of invasive or enhanced drug therapies (surgical myectomy, alcohol septal ablation, disopyramide and mavacamten) in patients with postprandial LVOTO. Consecutive HCM patients without LVOTO underwent routine and postprandial echocardiography at rest, with provocation (Valsalva and standing) and after symptom-limited treadmill stress. RESULTS: Among 252 patients (mean age 58 years, 39% women), postprandial LVOT gradients were higher compared with routine echocardiography at rest (median 9.0 [0-38.0] vs 0 [0-14.0] mmHg, p<0.0001) and with provocation (18.5 [0-70.3] vs 1.5 [0-41.0] mmHg, p<0.0001). Postprandial exercise (PPXSE) gradients were higher in a subset of 44 patients who underwent both postprandial and fasting stress echocardiography, (47.0 [5.3-81.0] vs 17.5 [0-46.0] mmHg, p<0.0001). In total, 49 (19.5%) patients achieved the ≥50 mmHg threshold under routine conditions (rest/provocation); 90 (35.7%) additional patients achieved postprandial gradients ≥50 mmHg (rest/provocation/exercise), 38 (15.1%) with PPXSE alone. A total of 71 patients were treated with 91 invasive or enhanced drug therapies, 32 (45.1%) of whom had gradients ≥50 mmHg only after eating (rest/provocation) and 8 (11.3%) only with PPXSE, with symptom relief in the majority. CONCLUSIONS: Postprandial echocardiography was useful at unmasking LVOTO in more than one third of patients who did not have high gradients otherwise. Eating before echocardiography is a powerful provocative tool in the evaluation of patients with HCM.

Intraoperative Use of Intra-Aortic Balloon Pump to Generate Pulsatile Flow During Heart Transplantation: A Single-Center Experience.

The physiologic impact of pulsatile flow (PF) on end-organ perfusion during cardiopulmonary bypass (CPB) is controversial. Using an intra-aortic balloon pump (IABP) to maintain PF during CPB for patients undergoing heart transplantation (HT) may impact end-organ perfusion, with implications for postoperative outcomes. A single-center retrospective study of 76 patients bridged to HT with IABP was conducted between January 2018 and December 2022. Beginning in May 2022, patients received IABP-generated PF during CPB at an internal rate of 80 beats/minute. Fifty-eight patients underwent HT with the IABP turned off (IABP-Off), whereas 18 patients underwent HT with IABP-generated PF (IABP-On). The unmatched IABP-On group experienced shorter organ ischemia times (180 vs. 203 minutes, p = 0.015) and CPB times (104 vs. 116 minutes, p = 0.022). The cohort was propensity matched according to age, organ ischemia time, and CPB time. Elevations in postoperative lactates in the immediate (2.8 vs. 1.5, p = 0.062) and 24 hour (4.7 vs. 2.4, p = 0.084) postoperative periods trended toward significance in the matched IABP-Off group. There was no difference in postoperative vasoactive inotropic score (VIS), postoperative creatinine, or length of stay. This limited preliminary data suggest that maintaining counterpulsation to generate PF during CPB may improve end-organ perfusion in this patient population as suggested by lower postoperative lactate levels.

Impact of the coronavirus disease 2019 pandemic on drug overdoses in the United States and the effect on cardiac transplant volume and survival.

BACKGROUND: Drug overdose (DO) deaths rose to unprecedented levels during the coronavirus disease 2019 (COVID-19) pandemic. This study examines the impact of COVID-19 on the availability of cardiac allografts from DO donors and the implications of DO donor use on recipient survival. METHODS: Heart transplants reported to the United Network for Organ Sharing from January 2017 to November 2019 ("pre-COVID") and from March 2020 to June 2021 ("COVID pandemic") were analyzed with respect to DO donor status. Outcomes were analyzed using Kaplan-Meier survival and Cox regression to identify predictors of survival. Characteristics of discarded cardiac allografts were also compared by DO donor status. RESULTS: During the COVID-19 pandemic, 27.2% of cardiac allografts were from DO donors vs 20.5% pre-COVID, a 32.7% increase (p < 0.001). During the pandemic, DO donors were younger (84.7% vs 76.3% <40 years, p < 0.001), had higher cigarette use (16.1% vs 10.8%, p < 0.001), higher cocaine use (47.4% vs 19.7%, p < 0.001), and higher incidence of hepatitis C antibodies (26.8% vs 6.1%, p < 0.001) and RNA positivity (16.2% vs 4.2%, p < 0.001). While DO donors were less likely to require inotropic support (30.8% vs 35.4%, p = 0.008), they were more likely to have received cardiopulmonary resuscitation (95.3% vs 43.2%, p < 0.001). Recipient survival was equivalent using Kaplan-Meier analysis (log-rank, p = 0.33) and survival probability at 36 months was 85.6% (n at risk = 398) for DO donors vs 83.5% (n at risk = 1,633) for all other donors. Cox regression demonstrated that DO donor status did not predict mortality (hazard ratio 1.05; 95% confidence interval 0.90-1.23, p = 0.53). CONCLUSIONS: During the COVID-19 pandemic, there was a 32.7% increase in heart transplants utilizing DO donor hearts, and DO became the most common mechanism of death for donors. The use of DO donor hearts did not have an impact on short-term recipient survival.

Routine Extubation in the Operating Room After Isolated Coronary Artery Bypass.

BACKGROUND: The benefits of fast-track extubation in the intensive care unit (ICU) after cardiac surgery are well established. Although extubation in the operating room (OR) is safe in carefully selected patients, widespread use of this strategy in cardiac surgery remains unproven. This study was designed to evaluate perioperative outcomes with OR vs ICU extubation in patients undergoing nonemergency, isolated coronary artery bypass grafting (CABG). METHODS: The Society of Thoracic Surgeons (STS) data for all single-center patients who underwent nonemergency isolated CABG over a 6-year interval were analyzed. Perioperative morbidity and mortality with ICU vs OR extubation were compared. RESULTS: Between January 1, 2017 and December 31, 2022, 1397 patients underwent nonemergency, isolated CABG; 891 (63.8%) of these patients were extubated in the ICU, and 506 (36.2%) were extubated in the OR. Propensity matching resulted in 414 pairs. In the propensity-matched cohort, there were no differences between the 2 groups in incidence of reintubation, reoperation for bleeding, total operative time, stroke or transient ischemic attack, renal failure, or 30-day mortality. OR-extubated patients had shorter ICU hours (14 hours vs 20 hours; P < .0001), shorter postoperative hospital length of stay (3 days vs 5 days; P < .0001), a greater likelihood of being discharged directly to home (97.3% vs 89.9%; P < .0001), and a lower 30-day readmission rate (1.7% vs 4.1%; P = .04). CONCLUSIONS: Routine extubation in the OR is a feasible and safe strategy for a broad spectrum of patients after nonemergency CABG, with no increase in perioperative morbidity or mortality. Wider adoption of routine OR extubation for nonemergency CABG is indicated.

Assessment of the well-being of significant others of cardiothoracic surgeons.

OBJECTIVES: We aimed to evaluate how the current working climate of cardiothoracic surgery and burnout experienced by cardiothoracic surgeons influences their spouses and significant others (SOs). METHODS: A 33-question well-being survey was developed by the American Association for Thoracic Surgery Wellness Committee and distributed by e-mail to the SOs of cardiothoracic surgeons and to all surgeon registrants of the 2020 and 2021 American Association for Thoracic Surgery Annual Meetings with a request to share it with their SO. The 5-item Likert-scale survey questions were dichotomized, and associations were determined by χ2 or independent samples t tests, as appropriate. RESULTS: Responses from 238 SOs were analyzed. Sixty-six percent reported that the stress on their cardiothoracic surgeon partner had a moderate to severe influence on their family, and 63% reported that their partner's work demands didn't leave enough time for family. Fifty-one percent reported that their partner rarely had time for intimacy, 27% reported poor work-life balance, and 23% reported that interactions at home were usually or always not good-natured. SOs were most affected when their partner was <5 years out from training, worked in private vs academic practice, and worked longer hours. Having children, particularly younger than age 19 years, and a lack of workplace support resources further diminished well-being. CONCLUSIONS: The current work culture of cardiothoracic surgeons adversely affects their SOs, and the risk for families is concerning. These data present a major area for exploration as we strive to understand and mitigate the factors that lead to burnout among cardiothoracic surgeons.

Subvalvular techniques enhanced with endoscopic robotic mitral valve repair.

Objective: Totally endoscopic intracardiac robotic surgery is generally limited to uncomplicated mitral valve surgery. With experience, our team has developed a more aggressive approach to robotic cardiac surgery that allows for repair of a broad spectrum of mitral valve pathologies. We report complex subvalvular procedural advancements associated with this approach secondary to enhanced team experience and capabilities. Methods: All robotic mitral procedures performed by a 2-surgeon team in a quaternary care medical center from July 2011 to May 2022 were reviewed. Natural language-processing techniques were used to analyze operative reports for subvalvular repair techniques. Complex subvalvular techniques included papillary muscle repositioning, division of secondary anterior leaflet chordae, septal myomectomy, division of aberrant left ventricular muscle band attachments, and left ventricular patch reconstruction. The surgical experience was divided into 2 periods: early robotic experience (pre-2018) versus late (2018 onwards). Baseline demographics, outcomes, and subvalvular techniques were analyzed and compared. Results: A total of 1287 intracardiac robotic operations were performed by a 2-surgeon team. Thirty-day mortality was 0.6% (8/1287). Mitral valve repair was performed in 1024 patients. The mean age was 61 years (range, 18-90 years), and 15% were >75 years old; 29 patients (2.8%) had previously undergone cardiac surgery. There was a significant increase with experience in the application of advanced subvalvular techniques between the early versus late period (52.3% [268/512] vs 74.2% [380/512] (P < .001)). Conclusions: An experienced 2-surgeon team can perform progressively more complex robotic subvalvular repair techniques. These subvalvular techniques are a surrogate for team proficiency and capabilities.

Pig-to-human heart xenotransplantation in two recently deceased human recipients.

Genetically modified xenografts are one of the most promising solutions to the discrepancy between the numbers of available human organs for transplantation and potential recipients. To date, a porcine heart has been implanted into only one human recipient. Here, using 10-gene-edited pigs, we transplanted porcine hearts into two brain-dead human recipients and monitored xenograft function, hemodynamics and systemic responses over the course of 66 hours. Although both xenografts demonstrated excellent cardiac function immediately after transplantation and continued to function for the duration of the study, cardiac function declined postoperatively in one case, attributed to a size mismatch between the donor pig and the recipient. For both hearts, we confirmed transgene expression and found no evidence of cellular or antibody-mediated rejection, as assessed using histology, flow cytometry and a cytotoxic crossmatch assay. Moreover, we found no evidence of zoonotic transmission from the donor pigs to the human recipients. While substantial additional work will be needed to advance this technology to human trials, these results indicate that pig-to-human heart xenotransplantation can be performed successfully without hyperacute rejection or zoonosis.

Extracorporeal Membrane Oxygenation Impact on Host Transcriptomic Response in Severe Coronavirus.

Background: Evidence suggests that patients critically ill with COVID-19 have a dysregulated host immune response that contributes to end-organ damage. Extracorporeal membrane oxygenation (ECMO) has been used in this population with varying degrees of success. This study was performed to evaluate the impact of ECMO on the host immunotranscriptomic response in these patients. Methods: Eleven patients critically ill with COVID-19 requiring ECMO underwent an analysis of cytokines and immunotranscriptomic pathways before ECMO (T1), after ECMO for 24 hours (T2), and 2 hours after ECMO decannulation (T3). A Multiplex Human Cytokine panel was used to identify cytokine changes, and immunotranscriptomic changes in peripheral leukocytes were evaluated by PAXgene and NanoString nCounter. Results: Differential gene expression of 11 host immune genes was noted at T2 compared with T1. The most significant genes were MD2 and MRC1, which code for binding ligands for the activation of toll-like receptors 2 and 4. Reactome analyses of differential gene expression demonstrated an impact on many of the body's most important immune inflammatory pathways. Conclusions: These findings suggest a temporal impact of ECMO on the host immunotranscriptomic response in patients critically ill with COVID-19.

Thoracoabdominal normothermic regional perfusion in donation after circulatory death does not restore brain blood flow.

Use of thoracoabdominal normothermic regional perfusion (TA-NRP) during donation after circulatory death (DCD) is an important advance in organ donation. Prior to establishing TA-NRP, the brachiocephalic, left carotid, and left subclavian arteries are ligated, thereby eliminating anterograde brain blood flow via the carotid and vertebral arteries. While theoretical concerns have been voiced that TA-NRP after DCD may restore brain blood flow via collaterals, there have been no studies to confirm or refute this possibility. We evaluated brain blood flow using intraoperative transcranial Doppler (TCD) in two DCD TA-NRP cases. Pre-extubation, anterior and posterior circulation brain blood flow waveforms were present in both cases, similar to the waveforms detected in a control patient on mechanical circulatory support undergoing cardiothoracic surgery. Following declaration of death and initiation of TA-NRP, no brain blood flow was detected in either case. Additionally, there was absence of brainstem reflexes, no response to noxious stimuli and no respiratory effort. These TCD results demonstrate that DCD with TA-NRP did not restore brain blood flow.

Donation after circulatory death heart transplantation using normothermic regional perfusion:The NYU Protocol.

Objective: This study aimed to evaluate the impact of cardiopulmonary bypass for thoraco-abdominal normothermic regional perfusion on the metabolic milieu of donation after cardiac death organ donors before transplantation. Methods: Local donation after cardiac death donor offers are assessed for suitability and willingness to participate. Withdrawal of life-sustaining therapy is performed in the operating room. After declaration of circulatory death and a 5-minute observation period, the cardiac team performs a median sternotomy, ligation of the aortic arch vessels, and initiation of thoraco-abdominal normothermic regional perfusion via central cardiopulmonary bypass at 37 °C. Three sodium chloride zero balance ultrafiltration bags containing 50 mEq sodium bicarbonate and 0.5 g calcium carbonate are infused. Arterial blood gas measurements are obtained every 15 minutes after every zero balance ultrafiltration bag is infused, and blood is transfused as needed to maintain hemoglobin greater than 8 mg/dL. Cardiopulmonary bypass is weaned with concurrent hemodynamic and transesophageal echocardiogram evaluation of the donor heart. The remainder of the procurement, including the abdominal organs, proceeds in a similar controlled fashion as is performed for a standard donation after brain death donor. Results: Between January 2020 and May 2022, 18 donation after cardiac death transplants using the thoraco-abdominal normothermic regional perfusion protocol were performed at our institution. The median donor age was 42.5 years (range, 20-51 years), and 88.9% (16/18) were male. The mean total donor cardiopulmonary bypass time was 88.8 ± 51.8 minutes. At the beginning of cardiopulmonary bypass, the average donor lactate was 9.4 ± 1.5 mmol/L compared with an average final lactate of 5.3 ± 2.7 mmol/L (P<.0001). The average beginning potassium was 6.5 ± 1.8 mmol/L compared with an average end potassium of 4.2 ± 0.4 mmol/L (P<.0001) . The average beginning hemoglobin was 6.8 ± 0.7 g/dL, and the average end hemoglobin was 8.2 ± 1.3 g/dL (P<.001) . On average, donation after cardiac death donors received transfusions of 2.3 ± 1.5 units of packed red blood cells. Of the 18 donors who underwent normothermic regional perfusion, all hearts were deemed suitable for recovery and successfully transplanted, a yield of 100%. Other organs successfully recovered and transplanted include kidneys (80.6% yield), livers (66.7% yield), and bilateral lungs (27.8% yield). Conclusions: The use of cardiopulmonary bypass for thoraco-abdominal normothermic regional perfusion is a burgeoning option for improving the quality of organs from donation after cardiac death donors. Meticulous intraoperative management of donation after cardiac death donors with a specific focus on improving their metabolic milieu may lead to improved graft function in transplant recipients.

Use of a novel digital drainage system after pulmonary resection.

Background: The Thoraguard Surgical Drainage System is a novel device for drainage of air and fluid after cardiothoracic surgery. Methods: A three-part study was conducted: a prospective observational safety and feasibility study, a retrospective comparison of patients managed with an analogue drainage system, and a clinician user-feedback survey. Results: Fifty patients underwent robotic pulmonary resection utilizing the Thoraguard system for postoperative drainage. The Thoraguard system detected a higher number of air leaks than an analogue system (36/50, 72% vs. 45/200, 23%; P<0.001) and was associated with decreased chest tube duration of 1 day [interquartile range (IQR) 0-2] vs. 2 days (IQR 2-3) (P=0.042) and hospital length of stay of 2 days (IQR 2-3) vs. 3 days (IQR 2-4) (P=0.027). Patients with a peak air leak less than 100 mL/min (32 patients, 64%), had a decreased median chest tube duration of 1 day (IQR 0-1) vs. 2.8 days (IQR 1-3) (P=0.004). Compared to an analogue system, the Thoraguard system had superior user-reported ability to detect air-leaks (17/23, 74%), better ease of patient ambulation (14/23, 61%), and better display of clinically relevant information (22/23, 96%). Conclusions: The Thoraguard Surgical Drainage System provides safe and effective drainage post pulmonary resection. Compared to an analogue system, the Thoraguard system detected a higher number of air leaks and was associated with decreased chest tube duration and hospital length of stay. User survey data reported superior air leak detection, display of clinical data, and ease of use of the Thoraguard system.