Effect of Preoperative Mitral Regurgitation on LVAD Outcomes in Patients with Elevated Pulmonary Vascular Resistance.

PURPOSE: In patients with end-stage heart failure who undergo left ventricular assist device (LVAD) implantation, higher pulmonary vascular resistance (PVR) is associated with higher right heart failure rates and ineligibility for heart transplant. Concomitant mitral regurgitation (MR) could potentially worsen pulmonary hemodynamics and lead to worse outcomes; however, its effects in this patient population have not been specifically examined. METHODS: Using an institutional database spanning November 2003 to August 2017, we retrospectively identified patients with elevated PVR who underwent LVAD implantation. Patients were stratified by concurrent MR: moderate/severe (PVR + MR) vs. mild/none (PVR - MR). Cumulative incidence functions and Fine-Gray competing risk regression were performed to assess the effect of MR on heart transplant rates and overall survival during index LVAD support. RESULTS: Of 644 LVAD recipients, 232 (171 HeartMate II, 59 HeartWare, 2 HeartMate III) had baseline PVR > 3 Woods units; of these, 124 (53%) were INTERMACS 1-2, and 133 (57%) had moderate/severe MR (≥ 3 +). Patients with PVR + MR had larger a baseline left ventricular end-diastolic diameter than patients with PVR - MR (87.9 ± 38.2 mm vs. 75.9 ± 38.0 mm; P = 0.02). Median clinical follow-up was 18.8 months (interquartile range: 4.7-36.4 months). Moderate/severe MR was associated with lower mortality rates during index LVAD support (adjusted hazard ratio 0.64, 95% CI 0.41-0.98; P = 0.045) and higher heart transplant rates (adjusted odds ratio 2.86, 95% CI 1.31-6.25; P = 0.009). No differences in stroke, gastrointestinal bleeding, or right heart failure rates were observed. CONCLUSIONS: Among LVAD recipients with elevated preoperative PVR, those with moderate/severe MR had better overall survival and higher transplant rates than those with mild/no MR. These hypothesis-generating findings could be explained by incremental LVAD benefits resulting from reduction of MR and better LV unloading in a subset of patients with larger ventricles at baseline. In patients with preoperative elevated PVR, MR severity may be a prognostic sign that can inform patient selection for end-stage heart failure therapy.

Minimally Invasive Mitral Valve Surgery Using a Cold Fibrillatory Cardiac Arrest Technique in Patients With Prior Cardiac Surgery.

OBJECTIVE: Minimally invasive mitral valve surgery (mini-MVS) is typically reserved for patients who have not undergone open cardiac surgery. In the reoperative setting, using intrapericardial dissection for crossclamping the aorta through a minimally invasive approach can be difficult and, at times, risky. Cold fibrillatory cardiac arrest (CFCA) with systemic cardiopulmonary bypass without cross-clamping is a well-described technique; however, data about its safety for patients who undergo reoperative mini-MVS are limited. METHODS: Data for 34 patients who underwent reoperative mini-MVS with CFCA from March 2017 to March 2022 were reviewed retrospectively. A mini right thoracotomy (n = 30) or robotic (n = 4) approach was used. Systemic hypothermia was induced to a target temperature of 25 °C. RESULTS: Patient mean (SD) age was 64.5 (9.6) years, and 15 of 34 (44.1%) patients were women. Of those 34 patients, 23 (67.6%) had severe regurgitation, and 11 (32.4%) had severe stenosis. Before mini-MVS, 28 patients had undergone valve surgery, and 8 had undergone coronary artery bypass graft surgery. The mitral valve was repaired in 5 of 34 (14.7%) and replaced in 29 of 34 (85.3%) patients. No difference was observed in preoperative and postoperative left ventricular function (P = .82). In 1 patient, kidney failure developed that necessitated dialysis. No postoperative stroke or mortality at 30 days occurred. CONCLUSION: Mini-MVS with CFCA is well tolerated in patients with prior cardiac surgery. Myocardial function was not impaired, nor was the risk of stroke increased in this cohort, indicating that CFCA is a safe alternative in this high-risk population.

Predictors and Impact of Prolonged Vasoplegia After Continuous-Flow Left Ventricular Assist Device Implantation.

Background: Vasoplegia after cardiac surgery is associated with adverse outcomes. However, the clinical effects of vasoplegia and the significance of its duration after continuous-flow left ventricular assist device (CF-LVAD) implantation are less known. Objectives: This study aimed to identify predictors of and outcomes from transient vs prolonged vasoplegia after CF-LVAD implantation. Methods: The study was a retrospective review of consecutive patients who underwent CF-LVAD implantation between January 1, 2005, and December 31, 2017. Vasoplegia was defined as the presence of all of the following: mean arterial pressure ≤65 mm Hg, vasopressor (epinephrine, norepinephrine, vasopressin, or dopamine) use for >6 hours within the first 24 hours postoperatively, cardiac index ≥2.2 L/min/m2 and systemic vascular resistance <800 dyne/s/cm5, and vasodilatory shock not attributable to other causes. Prolonged vasoplegia was defined as that lasting 12 to 24 hours; transient vasoplegia was that lasting 6 to <12 hours. Patient characteristics, outcomes, and risk factors were analyzed. Results: Of the 600 patients who underwent CF-LVAD implantation during the study period, 182 (30.3%) developed vasoplegia. Mean patient age was similar between the vasoplegia and no-vasoplegia groups. Prolonged vasoplegia (n = 78; 13.0%), compared with transient vasoplegia (n = 104; 17.3%), was associated with greater 30-day mortality (16.7% vs 5.8%; P = 0.02). Risk factors for prolonged vasoplegia included preoperative dialysis and elevated body mass index. Conclusions: Compared with vasoplegia overall, prolonged vasoplegia was associated with worse survival after CF-LVAD implantation. Treatment to avoid or minimize progression to prolonged vasoplegia may be warranted.

Risk Factors, Incidence, and Outcomes Associated With Clinically Significant Airway Ischemia.

Airway complications following lung transplantation remain an important cause of morbidity and mortality. We aimed to identify the incidence, risk factors and outcomes associated with clinically significant airway ischemia (CSAI) in our center. We reviewed 217 lung transplants (386 airway anastomoses) performed at our institution between February 2016 and December 2020. Airway images were graded using the 2018 ISHLT grading guidelines modified slightly for retrospective analysis. Airways were considered to have CSAI if they developed ischemia severity >B2, stenosis >50%, and/or any degree of dehiscence within 6-months of transplant. Regression analyses were used to evaluate outcomes and risk factors for CSAI. Eighty-two patients (37.8%) met criteria for CSAI. Of these, twenty-six (32%) developed stenosis and/or dehiscence, and 17 (21%) required interventions. Patients with CSAI had lower one-year (80.5% vs. 91.9%, p = 0.05) and three-year (67.1% vs. 77.8%, p = 0.08) survival than patients without CSAI. Factors associated with CSAI included younger recipient age, recipient diabetes, single running suture technique, performance of the left anastomosis first, lower venous oxygen saturation within 48-h, and takeback for major bleeding. Our single-center analysis suggests that airway ischemia remains a major obstacle in contemporary lung transplantation. Improving the local healing milieu of the airway anastomosis could potentially mitigate this risk.

Sex Disparities in Left Ventricular Assist Device Implantation: Delayed Presentation and Worse Right Heart Failure.

We explored whether women undergo continuous-flow left ventricular assist device (CF-LVAD) implantation in later stages of heart failure (HF) than men, evidenced by worse preoperative right HF (RHF). We also compared two propensity models with and without preoperative RHF to assess its effect on outcomes. INTERMACS was queried from July 2008 to December 2017. Propensity model 1 matched men and women on age ≥50 years, HF etiology, body surface area, INTERMACS class, comorbidities, device strategy, temporary mechanical circulatory support, and device type. Model 2 included these variables plus LV end-diastolic diameter, right atrial pressure/pulmonary capillary wedge pressure, pulmonary artery pulsatility index, and right ventricular ejection fraction. The primary outcome was all-cause mortality. Secondary outcomes comprise RHF, rehospitalization, renal dysfunction, stroke, and device malfunction. In model 1, characteristics were comparable between 3,195 women and 3,195 men, except women more often had preoperative RHF and postoperative right VAD support and had worse 1 year and overall survival. In model 2, after propensity matching for additional risk factors for preoperative RHF, 1,119 women and 1,119 men had comparable post-LVAD implant RVAD use and survival. These findings suggest that women present more often with biventricular failure and after implantation have higher RHF and mortality rates.

Incidence, Risk Score Performance, and In-Hospital Outcomes of Postoperative Atrial Fibrillation After Cardiac Surgery.

BACKGROUND: Postoperative atrial fibrillation (POAF) frequently complicates cardiac surgery. Predicting POAF can guide interventions to prevent its onset. This study assessed the incidence, risk factors, and related adverse outcomes of POAF after cardiac surgery. METHODS: A cohort of 1,606 patients undergoing cardiac surgery at a tertiary referral center was analyzed. Postoperative AF was defined based on the Society of Thoracic Surgeons' criteria: AF/atrial flutter after operating room exit that either lasted longer than 1 hour or required medical or procedural intervention. Risk factors for POAF were evaluated, and the performance of established risk scores (POAF, HATCH, COM-AF, CHA2DS2-VASc, and Society of Thoracic Surgeons risk scores) in predicting POAF was assessed using discrimination (area under the receiver operator characteristics curve) analysis. The association of POAF with secondary outcomes, including length of hospital stay, ventilator time, and discharge to rehabilitation facilities, was evaluated using adjusted linear and logistic regression models. RESULTS: The incidence of POAF was 32.2% (n = 517). Patients who developed POAF were older, had traditional cardiovascular risk factors and higher Society of Thoracic Surgeons risk scores, and often underwent valve surgery. The POAF risk score demonstrated the highest area under the receiver operator characteristics curve (0.65), but risk scores generally underperformed. Postoperative AF was associated with extended hospital stays, longer ventilator use, and higher likelihood of discharge to rehabilitation facilities (odds ratio, 2.30; 95% CI, 1.73-3.08). CONCLUSION: This study observed a high incidence of POAF following cardiac surgery and its association with increased morbidity and resource utilization. Accurate POAF prediction remains elusive, emphasizing the need for better risk-prediction methods and tailored interventions to diminish the effect of POAF on patient outcomes.

Clinical Predictors and Outcomes After Left Ventricular Assist Device Implantation and Tracheostomy.

BACKGROUND: Postoperative respiratory failure is a major complication that affects up to 10% of patients who undergo cardiac surgery and has a high in-hospital mortality rate. Few studies have investigated whether patients who require tracheostomy for postoperative respiratory failure after continuous-flow left ventricular assist device (CF-LVAD) implantation have worse survival outcomes than patients who do not. OBJECTIVE: To identify risk factors for respiratory failure necessitating tracheostomy in CF-LVAD recipients and to compare survival outcomes between those who did and did not require tracheostomy. METHODS: Consecutive patients who underwent primary CF-LVAD placement at a single institution between August 1, 2002, and December 31, 2019, were retrospectively reviewed. Propensity score matching accounted for baseline differences between the tracheostomy and nontracheostomy groups. Multivariate logistic regression was used to identify tracheostomy risk factors and 90-day survival; Kaplan-Meier analysis was used to assess midterm survival. RESULTS: During the study period, 664 patients received a CF-LVAD; 106 (16.0%) underwent tracheostomy for respiratory failure. Propensity score matching produced 103 matched tracheostomy-nontracheostomy pairs. Patients who underwent tracheostomy were older (mean [SD] age, 57.9 [12.3] vs 54.6 [13.9] years; P = .02) and more likely to need preoperative mechanical circulatory support (61.3% vs 47.8%; P = .01) and preoperative intubation (27.4% vs 8.8%; P < .001); serum creatinine was higher in the tracheostomy group (mean [SD], 1.7 [1.0] vs 1.4 [0.6] mg/dL; P < .001), correlating with tracheostomy need (odds ratio, 1.76; 95% CI, 1.21-2.56; P = .003). Both before and after propensity matching, 30-day, 60-day, 90-day, and 1-year survival were worse in patients who underwent tracheostomy. Median follow-up was 0.8 years (range, 0.0-11.2 years). Three-year Kaplan-Meier survival was significantly worse for the tracheostomy group before (22.0% vs 61.0%; P < .001) and after (22.4% vs 48.3%; P < .001) matching. CONCLUSION: Given the substantially increased probability of death in patients who develop respiratory failure and need tracheostomy, those at high risk for respiratory failure should be carefully considered for CF-LVAD implantation. Comprehensive management to decrease respiratory failure before and after surgery is critical.

Twenty-year survival following lung transplantation.

Background: Lung transplantation median survival has seen improvements due to recognition of short-term survival factors but continues to trail behind other solid organs due to limited understanding of long-term survivorship. Given the creation of the United Network for Organ Sharing (UNOS) database in 1986, it was difficult to accrue data on long-term survivors until recently. This study characterizes factors impacting lung transplant survival beyond 20 years, conditional to 1-year survival. Methods: Lung transplant recipients listed in UNOS from 1987 to 2002 who survived to 1 post-transplant year were reviewed. Kaplan-Meier and adjusted Cox regression analyses were performed at 20 and 10 years to identify risk factors associated with long-term outcomes independent of their short-term effects. Results: A total of 6,172 recipients were analyzed, including 472 (7.6%) recipients who lived 20+ years. Factors associated with increased likelihood of 20-year survival were female-to-female gender match, recipient age 25-44, waitlist time >1 year, human leukocyte antigen (HLA) mismatch level 3, and donor cause of death: head trauma. Factors associated with decreased 20-year survival included recipient age ≥55, chronic obstructive pulmonary disease/emphysema (COPD/E) diagnosis, donor smoking history >20 pack-years, unilateral transplant, blood groups O&AB, recipient glomerular filtration rate (GFR) <10 mL/min, and donor GFR 20-29 mL/min. Conclusions: This is the first study identifying factors associated with multiple-decade survival following lung transplant in the United States. Despite its challenges, long-term survival is possible and more likely in younger females in good waitlist condition without COPD/E who receive a bilateral allograft from a non-smoking, gender-matched donor of minimal HLA mismatch. Further analysis of the molecular and immunologic implications of these conditions are warranted.

Impact of time off anticoagulation in patients with continuous-flow left ventricular assist devices.

Patients with left ventricular assist devices (LVADs) receive anticoagulation to decrease the risk of thrombosis. Various circumstances require discontinuing anticoagulation in LVAD patients, but the risks entailed are not well defined. In a retrospective review of LVAD implantation procedures, we examined the effect of time off anticoagulation on thrombosis and mortality rates after implantation. An international normalized ratio ≤ 1.5 was used to screen for patients taken off anticoagulation. Patients were divided into three groups by the cumulative number of days off anticoagulation: no discontinuation, short-term discontinuation (< 30 days), and long-term discontinuation (≥ 30 days). Rates of ischemic stroke, pump thrombosis, and mortality were compared among groups. Of 245 patients who underwent LVAD implantation during the study, 70 (28.6%) were off anticoagulation during follow-up: 37 (15.1%) had short-term discontinuation (median, 11 days), and 33 (13.5%) had long-term discontinuation (median, 124 days). Patients with long-term discontinuation had a higher rate of ischemic stroke (adjusted hazard ratio 8.5, p = 0.001) and death (adjusted hazard ratio 3.9, p = 0.001). The three groups did not differ in pump thrombosis rate. We conclude that after LVAD implantation, discontinuing anticoagulation for ≥ 30 days is independently associated with an increased risk of ischemic stroke and death.

COMPETENCE Trial: The EVAHEART 2 continuous flow left ventricular assist device.

BACKGROUND: Continuous flow left ventricular assist devices have improved outcomes in patients with end-stage heart failure that require mechanical circulatory support. Current devices have an adverse event profile that has hindered widespread application. The EVAHEART®2 left ventricular assist device (EVA2) has design features such as large blood gaps, lower pump speeds and an inflow cannula that does not protrude into the left ventricle that may mitigate the adverse events currently seen with other continuous flow devices. METHODS: A prospective, multi-center randomized non-inferiority study, COMPETENCE Trial, is underway to assess non-inferiority of the EVA2 to the HeartMate 3 LVAS when used for the treatment of refractory advanced heart failure. The primary end-point is a composite of the individual primary outcomes: Survival to cardiac transplant or device explant for recovery; Free from disabling stroke; Free from severe Right Heart Failure after implantation of original device. Randomization is in a 2:1 (EVA2:HM3) ratio. RESULTS: The first patient was enrolled into the COMPETENCE Trial in December of 2020, and 25 subjects (16 EVA2 and 9 HM3) are currently enrolled. Enrollment of a safety cohort is projected to be completed by third quarter of 2022 at which time an interim analysis will be performed. Short-term cohort (92 EVA2 subjects) and long-term cohort is expected to be completed by the end of 2023 and 2024, respectively. CONCLUSIONS: The design features of the EVA2 such as a novel inflow cannula and large blood gaps may improve clinical outcomes but require further study. The ongoing COMPETENCE trial is designed to determine if the EVA2 is non-inferior to the HM3.

Extracorporeal Membrane Oxygenation for COVID-19: Collaborative Experience From the Texas Medical Center in Houston With 2 Years Follow-Up.

Patients with severe refractory hypoxemic respiratory failure may benefit from extracorporeal membrane oxygenation (ECMO) for salvage therapy. The Coronavirus disease 2019 (COVID-19) pandemic offered three high-volume independent ECMO programs at a large medical center the chance to collaborate to optimize ECMO care at the beginning of the pandemic in Spring 2020. Between March 15, 2020, and May 30, 2020, 3,615 inpatients with COVID-19 were treated at the Texas Medical Center. During this time, 35 COVID-19 patients were cannulated for ECMO, all but one in a veno-venous configuration. At hospital discharge, 23 (66%) of the 35 patients were alive. Twelve patients died of vasodilatory shock (n = 9), intracranial hemorrhage (n = 2), and cannulation-related bleeding and multiorgan dysfunction (n = 1). The average duration of ECMO was 13.6 days in survivors and 25.0 days in nonsurvivors ( p < 0.04). At 1 year follow-up, all 23 discharged patients were still alive, making the 1 year survival rate 66% (23/35). At 2 years follow-up, the overall rate of survival was 63% (22/35). Of those patients who survived 2 years, all were at home and alive and well at follow-up.

Preoperative hyponatremia and survival after left ventricular assist device implantation.

BACKGROUND: Hyponatremia is associated with adverse outcomes in heart failure and after cardiac surgery. We hypothesized that hyponatremia is associated with poorer short-term and longer term survival in patients after continuous-flow left ventricular assist device (CF-LVAD) placement. METHODS: We reviewed a single-center database of patients who received a CF-LVAD during 2012-2017. Sodium (Na) values obtained within 14 days before CF-LVAD insertion were averaged; patients (n = 332) were divided into hyponatremia (mean Na <135 mEq/L; n = 160; 48.2%) and normonatremia groups (mean Na 135-145 mEq/L; n = 172; 51.8%). Patients requiring preoperative dialysis or pump exchange were excluded. We compared outcomes between preoperative hyponatremia and normonatremia groups. RESULTS: The two groups' baseline characteristics were similar, although hyponatremia patients more often had preoperative mechanical circulatory support (44.4% vs. 31.4%, p = 0.002). Although hyponatremic and normonatremic patients did not differ in 30-day mortality (7.5% vs. 6.5%, p = 0.7), preoperative hyponatremia was associated with greater 5-year mortality (61% vs. 44%, p = 0.03). On binary logistic regression analysis, the strongest independent predictors of late mortality were hyponatremia (odds ratio [OR] 1.88, 95% CI [1.07-3.31], p = 0.02), older age (OR 1.03, 95% CI [1.01-1.05], p = 0.01), and elevated mean right atrial pressure/pulmonary capillary wedge pressure ratio (OR 4.69, 95% CI [1.76-12.47], p = 0.002). CONCLUSIONS: Hyponatremia was not associated with greater early mortality but was associated with poorer late survival. The optimal timing of LVAD implantation in relation to hyponatremia, and whether correcting hyponatremia perioperatively improves long-term survival, should be investigated.

Extracorporeal membrane oxygenation as a bridge to durable left ventricular assist device implantation in INTERMACS-1 patients.

Left ventricular assist devices (LVADs) are increasingly used as destination therapy or as a bridge to future cardiac transplant in patients with end-stage heart failure. Extracorporeal membrane oxygenation (ECMO) can be used to bridge patients in cardiogenic shock or with decompensated heart failure to durable mechanical circulatory support. We assessed outcomes in patients in critical cardiogenic shock (Interagency Registry for Mechanically Assisted Circulatory Support [INTERMACS] profile 1) who underwent implantation of a continuous-flow (CF)-LVAD, with or without preoperative ECMO bridging. For this retrospective study, we selected INTERMACS profile 1 patients who underwent CF-LVAD implantation at our institution between Sep 1, 2004 and Nov 30, 2018. Of 768 patients identified, 133 (17.3%) were INTERMACS profile 1; 26 (19.5%) received preoperative ECMO support, and 107 (80.5%) did not. Postimplantation outcomes were compared between the ECMO and no-ECMO groups. No significant differences were found in 30-day mortality (15.4 vs. 15.9%, P = 0.95) or survival at 1 year (53.8 vs. 60.9%, P = 0.51). Three patients who received ECMO before CF-LVAD implantation subsequently underwent cardiac transplant. In the ECMO group, the lactate level 1 day after ECMO initiation was lower in survivors than nonsurvivors (2.7 ± 2.2 vs. 7.4 ± 4.2 mmol/L, P = 0.02; area under the curve = 0.85, P = 0.01) after CF-LVAD implantation. Bridging with ECMO to CF-LVAD implantation in carefully selected INTERMACS profile 1 patients (those who are at the highest risk for critical cardiogenic shock and for whom palliation may be the only other option) produced acceptable postoperative outcomes.Field of research: Artificial lung/ECMO.

Predictors of renal replacement therapy in patients with continuous flow left ventricular assist devices.

Renal replacement therapy (RRT) after continuous flow left ventricular assist device (CF-LVAD) implantation significantly affects patients' quality of life and survival. To identify preoperative prognostic markers in patients requiring RRT after CF-LVAD implantation, we retrospectively reviewed data from patients who underwent implantation of a CF-LVAD at our institution during 2012-2017. Patients who required preoperative RRT were excluded. Preoperative and operative characteristics, as well as survival and adverse events, were compared between 74 (22.2%) patients requiring any duration of postoperative RRT and 259 (77.8%) not requiring RRT. Patients requiring RRT experienced more postoperative complications than patients who did not, including respiratory failure necessitating tracheostomy (35.7% vs 2.5%, p < 0.001), reoperation for bleeding (34.3% vs 11.7%, p < 0.001), and right heart failure necessitating perioperative mechanical circulatory support (32.4% vs 6.9%, p < 0.001). Patients requiring postoperative RRT also had poorer survival at 30 days (74.7% vs 98.8%), 6 months (48.2% vs 95.1%), and 12 months (45.3% vs 90.2%) (p < 0.001). Significant predictors of RRT after CF-LVAD implantation included urine proteinuria (odds ratio [OR] 3.6, 95% confidence interval [CI] [1.7-7.6], p = 0.001), estimated glomerular filtration rate < 45 mL/min/1.73 m2 (OR 3.4, 95% CI [1.5-17.8], p = 0.004), and mean right atrial pressure to pulmonary capillary wedge pressure ratio ≥ 0.54 (OR 2.6, 95% CI [1.3-5.], p = 0.01). Of the 74 RRT patients, 11 (14.9%) recovered renal function before discharge, 36 (48.6%) still required RRT after discharge, and 27 (36.5%) died before discharge. We conclude that preoperative renal and right ventricular dysfunction significantly predict postoperative renal failure and mortality after CF-LVAD implantation.