Long-Term Safety and Efficacy of Intraoperative Leadless Pacemaker Implantation During Valve Surgery.

BACKGROUND: Intraoperative implantation of leadless cardiac pacemakers (LCPs) under direct visualization during cardiac surgery is a novel strategy to provide pacing to patients with an elevated risk of postoperative conduction disorders or with a preexisting pacing indication undergoing valve surgery. OBJECTIVES: This study sought to evaluate the long-term safety and efficacy of intraoperative LCP implantation in 100 consecutive patients. METHODS: Retrospective single-center cohort study of consecutive patients (n = 100) who underwent intraoperative LCP implantation during valve surgery. Safety and efficacy were assessed at implantation and follow-up visits. RESULTS: A total of 100 patients (age 68 ± 13 years, 47% female) underwent intraoperative LCP implantation. The surgery involved the tricuspid valve in 99 patients (99%), including tricuspid valve repair in 59 (59%) and tricuspid valve replacement in 40 (40%). Most of the patients (78%) underwent multivalve surgery. The indication for LCP implantation was elevated risk of postoperative atrioventricular block in 54% and preexisting bradyarrhythmias in 46%. LCP implantation was successful in all patients. During a median of 10.6 months (IQR: 2.0-22.7 months) of follow-up, no device-related complications occurred. At 12-month follow-up, the pacing thresholds were acceptable (≤2.0 V at 0.24 milliseconds) in 95% of patients. CONCLUSIONS: Intraoperative LCP implantation under direct visualization is a safe strategy to provide permanent pacing in patients undergoing valve surgery, with a postoperative electrical performance comparable to percutaneously placed LCPs.

Noncomplex ventricular arrhythmia associated with greater freedom from recurrent ectopy at 1 year after mitral repair surgery.

Objective: The effect of mitral valve (MV) surgery on the natural history of ventricular arrhythmia (VA) in patients with arrhythmic MV prolapse remains unknown. We sought to evaluate the cumulative incidence of VA at 1 year after surgical mitral repair. Methods: A retrospective review of progressively captured data identified 204 consecutive patients who underwent elective MV repair for significant degenerative mitral regurgitation as a first-time cardiovascular intervention in a quaternary reference center between January 2018 and December 2020. A subset of 62 consecutive patients with diagnosed arrhythmic MV prolapse was further evaluated for recurrent VA after MV repair. Results: The median age was 62 years (range, 27-77 years) and 26 of 62 (41.9%) were female. The median time from initial mitral regurgitation/MV prolaspe diagnosis-to-referral was 13.8 years (interquartile range [IQR], 5.4-25) and from VA diagnosis-to-referral was 8 years (IQR, 3-10.6). Using the Lown-Wolf classification, complex VA (Lown grade ≥3) was identified in 36 of 62 patients (58%) at baseline, whereas 8 of 62 (13%) had a cardioverter/defibrillator implanted for primary (4/8) or secondary (4/8) prevention. Left ventricular myocardial scar was confirmed in 23 of 34 (68%) of patients scanned at baseline. The prevailing valve phenotype was bileaflet Barlow (59/62; 95.2%). All patients underwent surgical MV repair by the same team. Surgical repair was stabilized with an annuloplasty prosthesis (median size 36 mm [IQR, 34-38]). Concomitant procedures included tricuspid valve repair (51/62; 82.3%), cryo-maze ± left atrial appendage exclusion (14/62, 23%), and endocardial cryoablation of VA ectopy (4/62; 6.5%). The 30-day and 1-year freedom from recurrent VA were 98.4% and 75.9%, respectively. Absent VA after mitral repair was uniformly observed in patients with minor VA at baseline. Absent VA after mitral repair was uniformly observed in patients with minor VA preoperatively. Complex baseline VA was the strongest predictor of recurrent VA (hazard ratio, 10.8; 95% confidence interval, 1.4-84.2; P = .024), irrespective of myocardial fibrosis. Conclusions: In a series of 62 consecutive patients operated electively for arrhythmic mitral prolapse, VA remained undetected in 75.9% of patients at 1 year. Freedom from recurrent VA was greater among patients without complex VA preoperatively, whereas baseline Lown grade ≥3 was the strongest independent risk factor for recurrent VA at 1 year. These findings attest to the importance of early recognition and prompt referral of patients with mitral prolapse and progressive VA to specialty interdisciplinary care.

Ventricular assist device using a thoracotomy-based implant technique: Multi-Center Implantation of the HeartMate 3 in Subjects With Heart Failure Using Surgical Techniques Other Than Full Median Sternotomy (HM3 SWIFT).

OBJECTIVES: The HeartMate 3 (Abbott) left ventricular assist device provides substantial improvement in long-term morbidity and mortality in patients with advanced heart failure. The Implantation of the HeartMate 3 in Subjects With Heart Failure Using Surgical Techniques Other Than Full Median Sternotomy study compares thoracotomy-based implantation clinical outcomes with standard median sternotomy. METHODS: We conducted a prospective, multicenter, single-arm study in patients eligible for HeartMate 3 implantation with thoracotomy-based surgical technique (bilateral thoracotomy or partial upper sternotomy with left thoracotomy). The composite primary end point 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 postimplant (elective transplants were treated as a success). The primary end point (noninferiority, -15% margin) was assessed with >90% power compared with a propensity score-matched cohort (ratio 1:2) derived from the Multi-Center Study of MagLev Technology in Patients Undergoing Mechanical Circulatory Support Therapy With HeartMate 3 continued access protocol. 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 Implantation of the HeartMate 3 in Subjects With Heart Failure Using Surgical Techniques Other Than Full Median Sternotomy study group, noninferiority criteria was met (absolute between-group difference, -1.2%; Farrington Manning lower 1-sided 95% CI, -9.3%; P < .0025) and event-free survival was not different (85.0% vs 86.2%; hazard ratio, 1.01; 95% CI, 0.58-2.10). Length of stay with thoracotomy-based implant was longer (median, 20 vs 17 days; P = .03). No differences were observed for blood product utilization, adverse events (including right heart failure), functional status, and quality of life between cohorts. CONCLUSIONS: Thoracotomy-based implantation of the HeartMate 3 left ventricular assist device is noninferior to implantation via standard full sternotomy. This study supports thoracotomy-based implantation as an additional standard for surgical implantation of the HeartMate 3 left ventricular assist device.

Total artificial heart implantation as a bridge to transplantation in the United States.

OBJECTIVES: Although the SynCardia total artificial heart (SynCardia Systems, LLC) was approved for use as a bridge to transplantation in 2004 in the United States, most centers do not adopt the total artificial heart as a standard bridging strategy for patients with biventricular failure. This study was designed to characterize the current use and outcomes of patients placed on total artificial heart support. METHODS: The United Network of Organ Sharing Standard Transplant Research File was queried to identify total artificial heart implantation in the United States between 2005 and 2018. Multivariable Cox regression models were used for risk prediction. RESULTS: A total of 471 patients (mean age, 49 years; standard deviation, 13 years; 88% were male) underwent total artificial heart implantation. Of 161 transplant centers, 11 centers had cumulative volume of 10 or more implants. The 6-month cumulative incidence of mortality on the total artificial heart was 24.6%. The 6-month cumulative incidence of transplant was 49.0%. The 1-year mortality post-transplantation was 20.0%. Cumulative center volume less than 10 implants was predictive of both mortality on the total artificial heart (hazard ratio, 2.2, 95% confidence interval, 1.5-3.1, P < .001) and post-transplant mortality after a total artificial heart bridge (hazard ratio, 1.5, 95% confidence interval, 1.0-2.2, P = .039). CONCLUSIONS: Total artificial heart use is low, but the total artificial heart can be an option for biventricular bridge to transplant with acceptable bridge to transplant and post-transplant survival, especially in higher-volume centers. The observation of inferior outcomes in lower-volume centers raises questions as to whether targeted training, center certifications, and minimum volume requirements could improve outcomes for patients requiring the total artificial heart.

Heparin-induced thrombocytopaenia complicating cardiogenic shock requiring durable mechanical circulatory support: a case report.

Background: Heparin-induced thrombocytopaenia (HIT) is an immune-mediated reaction to heparin therapy that may lead to life-threatening thrombotic events. This disorder complicates intraoperative heparin use during left ventricular assist device (LVAD) implantation. Case summary: A 52-year-old man presented in acute decompensated heart failure. His admission laboratory studies were consistent with cardiogenic shock with a lactate of 6.1 mmol/L (ref range 0.50-1.99 mmol/L). Echocardiogram and CT scan demonstrated severe biventricular dysfunction and a left ventricular ejection fraction of 10%, as well as left upper lobe segmental pulmonary embolism. He was started on inotropes, diuretics, and a heparin infusion. Following heparin initiation, his platelets had decreased by 63% to a nadir of 39 000/µL (ref range 150 000-450 000/µL) and testing confirmed a diagnosis of HIT. His shock state worsened to INTERMACS 1 necessitating escalation of mechanical support. In preparation for HeartMate 3 LVAD implantation, he received 3 cycles of plasmapheresis with one session of IVIG perioperatively, resulting in a 60% reduction in the titre of heparin-dependent platelet antibodies. He underwent successful LVAD implantation including usage of intraoperative heparin, and was discharged home on post-operative Day 17, where he has remained stable on LVAD support. Discussion: Limited data exist on the perioperative management of patients with HIT undergoing LVAD implantation. Heparin is preferred to other antithrombin agents during surgery due to the availability of an immediate reversal agent. Plasmapheresis with IVIG is a potential management option to decrease heparin-dependent platelet antibodies in patients with HIT to allow for successful LVAD implantation.

Outcomes of Simultaneous Heart and Kidney Transplantation.

BACKGROUND: Simultaneous heart-kidney transplantation has been increasingly performed in end-stage heart failure patients with concurrent kidney dysfunction despite limited evidence supporting its indications and utility. OBJECTIVES: The purpose of this study was to investigate the effects and utility of simultaneously implanted kidney allografts with various degrees of kidney dysfunction during heart transplantation. METHODS: Using the United Network for Organ Sharing registry, long-term mortality was compared in recipients with kidney dysfunction who underwent heart-kidney transplantation (n = 1,124) vs isolated heart transplantation (n = 12,415) in the United States between 2005 and 2018. In heart-kidney recipients, contralateral kidney recipients were compared for allograft loss. Multivariable Cox regression was used for risk adjustment. RESULTS: Long-term mortality was lower among heart-kidney recipients than among heart-alone recipients when recipients were on dialysis (26.7% vs 38.6% at 5 years; HR: 0.72; 95% CI: 0.58-0.89) or had a glomerular filtration rate (GFR) of <30 mL/min/1.73 m2 (19.3% vs 32.4%; HR: 0.62; 95% CI: 0.46-0.82) and GFR of 30 to 45 mL/min/1.73 m2 (16.2% vs 24.3%; HR: 0.68; 95% CI: 0.48-0.97) but not in GFR of 45 to 60 mL/min/1.73 m2. Interaction analysis showed that the mortality benefit of heart-kidney transplantation continued up to GFR 40 mL/min/1.73 m2. The incidence of kidney allograft loss was higher among heart-kidney recipients than among contralateral kidney recipients (14.7% vs 4.5% at 1 year; HR: 1.7; 95% CI: 1.4-2.1). CONCLUSIONS: Heart-kidney transplantation relative to heart transplantation alone provided superior survival for dialysis-dependent recipients and non-dialysis-dependent recipients up to a GFR of approximately 40 mL/min/1.73 m2 but at the cost of almost twice the risk of kidney allograft loss than contralateral kidney allograft recipients.

A bridge-to-bridge approach to heart transplantation using extracorporeal membrane oxygenation and total artificial heart.

BACKGROUND: This study aims to describe the outcomes after heart transplantation using a bridge-to-bridge strategy with a sequence of extracorporeal membrane oxygenation (ECMO) support followed by temporary total artificial heart implantation (TAH-t). METHODS: A retrospective, multicenter analysis of 54 patients who underwent TAH-t implantation following an ECMO for cardiogenic shock was performed (ECMO-TAH-t group). A control group of 163 patients who underwent TAH-t implantation as a direct bridge to transplantation (TAH-t group) was used to assess this strategy's impact on outcomes. RESULTS: Fifty-four patients, averaging 47 ± 13 year old, underwent implantation of a TAH-t after 5.3 ± 3.4 days of ECMO perfusion for cardiogenic shock. In the ECMO-TAH-t group, 20 patients (20/54%; 37%) died after TAH-t implantation and 57 patients (57/163%; 35%) died in the TAH-t group (Gray test; P = .49). The top 3 causes of death of patients on TAH-t support were multisystem organ failure (40%), sepsis (20%), and neurologic events (20%). Overall, 32 patients (32/54%; 59%) underwent heart transplantation in the ECMO-TAH-t group compared with 106 patients (106/163%, 65%) in the TAH-t group (P = .44). No significant difference in survival was observed at 6 months, 1 year, and 3 years after heart transplant (ECMO-TAH-t group: 94%, 87%, and 80% vs 87%, 83%, and 76% in the TAH-t group, respectively). Deterioration of liver function (bilirubin, aspartate transaminase, and alanine aminotransferase levels on TAH-t) was associated with increased mortality before heart transplant in both groups. CONCLUSIONS: Sequential bridging from ECMO to TAH-t followed by heart transplantation is a viable option for a group of highly selected patients.

Temporary mechanical circulatory support devices: practical considerations for all stakeholders.

Originally intended for life-saving salvage therapy, the use of temporary mechanical circulatory support (MCS) devices has become increasingly widespread in a variety of clinical settings in the contemporary era. Their use as a short-term, prophylactic support vehicle has expanded to include procedures in the catheterization laboratory, electrophysiology suite, operating room and intensive care unit. Accordingly, MCS device design and technology continue to develop at a rapid pace. In this Review, we describe the functionality, indications, management and complications associated with temporary MCS, together with scenario-specific utilization, goal-directed development and bioengineering of future devices. We address various considerations for the use of temporary MCS devices in both prophylactic and rescue scenarios, with input from stakeholders from various cardiovascular specialties, including interventional and heart failure cardiology, electrophysiology, cardiothoracic anaesthesiology, critical care and cardiac surgery.

Reversal of Total Artificial Heart Mechanical Valve Thrombosis Using Catheter-Directed Thrombolysis.

Total artificial heart is associated with increased incidence of thromboembolism, which can prove to be fatal. The presence of four metallic tilting discs increases the chances of thrombus formation and sudden obstruction of the valve in a closed position resulting in severe hemodynamic collapse. Such a condition is conventionally treated by a surgical approach for device change; however, this procedure is extremely high risk and associated with complications and poor outcomes. We describe two total artificial heart patients with sudden obstruction to the filling of the right side due to fixing of the atrioventricular valve in a closed position due to a thrombus. After a quick diagnosis by rescue transesophageal echocardiography, we successfully treated these patients with catheter-directed thrombolysis with minimal adverse outcomes. We propose a carefully weighed application of this approach in hemodynamically unstable patients too tenuous for a timely surgery and with low risk for bleeding.

Prediction of Survival After Implantation of a Fully Magnetically Levitated Left Ventricular Assist Device.

BACKGROUND: Clinical trials inform on average efficacy, but individualized risk assessments for outcome prediction are important in guiding treatment implementation. OBJECTIVES: The authors developed and validated a patient-specific risk score to predict survival at 1 and 2 years after HeartMate 3 (HM3) left ventricular assist device (LVAD) implantation. METHODS: The MOMENTUM 3 (Multicenter Study of MagLev Technology in Patients Undergoing Mechanical Circulatory Support Therapy with HeartMate 3) trial includes 2,200 HM3 LVAD patients in the pivotal trial and Continued Access Protocol study (2014-2018). The authors randomly assigned all patients to a derivation cohort (n = 1,540) or validation cohort (n = 660). Univariate mortality predictors were screened for potential model inclusion, stepwise selection was used to build the multivariable Cox proportional hazards regression model, and performance (discrimination and calibration) was evaluated. RESULTS: Age, prior cardiac surgery (coronary artery bypass grafting [CABG] or valve procedure), lower serum sodium, higher blood urea nitrogen (BUN), small left ventricular size, and right atrial pressure-to-pulmonary capillary wedge pressure (RAP/PCWP) ratio >0.6 were significant risk factors for mortality. Receiver-operating characteristic (ROC) analysis in the validation cohort demonstrated an area under the curve (AUC) of 0.76 (95% CI: 0.70-0.81) at 1 year and 0.71 (95% CI: 0.66-0.77) at 2 years. Calibration between predicted and observed survival of the risk quintiles was high, with Pearson correlation coefficients of 0.986 and 0.994 at 1 and 2 years, respectively. Patients were successfully stratified into tertiles with higher-than-average, average, and lower-than-average survival, and observed mortality risk increased by 2-fold from one tertile to the next. CONCLUSIONS: A practical, easy-to-use HM3 Survival Risk Score with 6 components was developed to accurately predict 1- and 2-year survival after HM3 LVAD implantation. The survival risk score can be used to provide individual survival estimates to facilitate shared decision making when considering HM3 LVAD therapy. (MOMENTUM 3 Trial Portfolio; NCT02224755, NCT02892955).

Use of Extracorporeal Membrane Oxygenation and Impella as Bridge to Surgery Through Imaging for Cardiogenic Shock.

Three-dimensional TEE, zoomed volume acquisition, oriented to the surgeon's view of the mitral valve. (A) The left atrial erspective demonstrates a flail A3 segment with a ruptured posteromedial papillary muscle (arrow). (B) Three-dimensional color Doppler demonstrates severe MR. (C, D) Three-dimensional transillumination; left atrial (left) and LV (right) perspective demonstrated. This technique was used to highlight the blood pool-tissue interface. The degree of transparency was adjusted to maximize the border definition between the ruptured posteromedial papillary muscle and blood pool and more clearly demonstrate the ruptured posteromedial papillary muscle (dashed arrow).

Leadless pacemaker implantation under direct visualization during valve surgery.

OBJECTIVE: The leadless cardiac pacemaker is typically implanted percutaneously and has been widely used for patients who have already undergone valve surgery. We sought to determine the feasibility and safety of implanting the leadless pacemaker under direct visualization during valve surgery. METHODS: We performed a retrospective analysis of consecutive adult patients (n = 15) who underwent implantation of a leadless pacemaker under direct visualization at the time of valve surgery. Indications for single-chamber pacing were sick sinus syndrome with pauses (53.3%), atrial fibrillation with slow ventricular rates (13.3%) or complete heart block (6.6%), and elevated risk for postoperative heart block (26.6%). Leadless pacemaker performance and pacing percentage were assessed. RESULTS: Patients' age was 67.5 ± 17 years, 6 patients (40%) were male, and 14 patients (93%) had atrial fibrillation. Isolated tricuspid valve replacement was performed in 5 patients (33.3%), and the remainder underwent multivalve surgery that included concomitant tricuspid valve repair/replacement. In 93% of the patients (n = 14), the immediate post-cardiopulmonary bypass pacing thresholds were normal (≤2.0 V at 0.24 ms) and normalized in the remaining patient by the next morning. The impedance/sensing values were normal and stable through follow-up (151 ± 119 days) in all patients. Reliable leadless pacemaker performance allowed for deferral of temporary epicardial wires in 11 patients (73%). There were no procedural complications or device malfunction. CONCLUSIONS: Leadless cardiac pacemaker implantation during valve surgery is feasible and safe. This hybrid approach to pacing may simplify the perioperative management of patients undergoing valve surgery who have an indication for single-chamber pacing.

Lessons from reoperations for mitral stenosis after mitral valve repair.

BACKGROUND: The durability of mitral valve repair (MVr) is usually defined by the absence of recurrent significant mitral regurgitation. Postrepair mitral stenosis (MS) is a less frequent and less studied mode of failure of MVr. We analyzed our experience in patients who underwent reoperation for postrepair MS to characterize mechanisms resulting in MS and to summarize reoperative surgical strategies and mid-term outcomes. METHODS: Using a prospective database, we retrospectively analyzed data on 35 consecutive patients who underwent reoperation for symptomatic moderate to severe MS between January 1, 2011, and February 1, 2020. RESULTS: The mean patient age was 61.4 ± 11.4 years, and 69% were female. The median annuloplasty ring size used at the initial repair was 28 mm (interquartile range, 26-30 mm). Additional repair techniques at the initial operation included leaflet resection in 12 patients (34%) and commissuroplasty or edge-to-edge repair in 6 patients (18%). At reoperation, the most common mechanism of MS was pannus ingrowth in 20 patients (57%), leaflet calcification in 12 (34%), commissural fusion in 5 (14%), and tunnel effect (functional MS) in 3 (9%). Twenty-two patients (63%) underwent valve replacement, and 13 (37%) underwent valve re-repair. In patients who underwent re-repair, annuloplasty revision was performed in all patients, with 6 patients (46%) converted from complete ring to band, 4 (11%) converted from ring to pericardial annuloplasty, 2 (6%) converted to no annuloplasty, and 1 (8%) with annuloplasty ring upsizing. There were no in-hospital or 1-year mortalities. Survival at the 5-year follow-up was 93.9%. CONCLUSIONS: MS causing late failure of MVr is frequently associated with smaller ring sizes and inflammatory or calcific changes in the valve. Highly selected patients may be good candidates for mitral valve re-repair.

Finding a proper "Mate": Comparison of left ventricular assist devices using cerebral oximetry.

INTRODUCTION: Axial-flow and centrifugal-flow left ventricular assist devices (LVAD) have been utilized in the management of heart failure, but it remains unknown whether these devices differ in end-organ perfusion. Our goal was to evaluate the association between device type and regional cerebral oxygen saturation (rSO2), and determine if this confers any benefit in short-term postoperative outcomes. METHODS: Adult patients who underwent primary LVAD implantation at our institution from 2014 to 2019 were retrospectively analyzed. Patients were stratified into axial-flow and centrifugal-flow groups. Intraoperative rSO2 readings were used to calculate the change in mean rSO2 from pre- to post-bypass. Multivariable modeling was performed to compare delta rSO2 between groups, and to analyze the association between LVAD type and postoperative outcomes. RESULTS: There were 152 patients included, of which 76 had an axial-flow device and 76 had a centrifugal-flow device implanted. The rSO2 level increased from pre-bypass to post-bypass on average 3.5% (CI: 2.1 to 5.0) for the axial group compared to 0.1% (CI: -1.2 to 1.4) for the centrifugal group, which was a significant difference (ß = -2.22, CI: -4.21 to -0.32, p = 0.022). Axial devices approached significance for lower odds of postoperative complications (OR: 0.35, CI: 0.11 to 1.06, p = 0.063), and were associated with significantly shorter ICU LOS (ß = -0.36, CI: -0.60 to -0.11, p = 0.004). CONCLUSION: Axial devices resulted in a greater increase in rSO2 than centrifugal pumps after separation from CPB. Further investigation is warranted to evaluate the effect of LVAD selection on long-term end-organ perfusion and subsequent patient outcomes.