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

OBJECTIVES: The objective of this single-center, pilot, prospective, and historical control study is to evaluate safety and feasibility outcomes associated with left atrial appendage exclusion (LAAE) concomitant with left ventricular assist device (LVAD) implantation via less invasive surgery (LIS) as a stroke prevention strategy. METHODS: A predefined number of 30 eligible subjects scheduled for LIS LVAD with LAAE were enrolled in the prospective arm between January 2020 and February 2021. Eligible retrospective LIS LVAD patients without LAAE were propensity-matched in a 1:1 ratio with the prospective arm subjects. The primary study objectives were to evaluate the safety, feasibility, and efficacy of the LAAE concomitant with LIS LVAD. RESULTS: Preoperative characteristics of patients in the Non-LAAE and LAAE groups were similar. LAAE was successfully excluded in all prospective patients (100%). Primary safety endpoints of chest tube output within the first 24 postoperative hours, Reoperation for bleeding within 48 h, and index hospitalization mortality demonstrated comparable safety of LAAE versus Non-LAAE with LIS LVAD. Cox proportional hazard regression demonstrated that LAAE with LIS LVAD was associated with 37% and 49% reduction in the risk of stroke and disabling stroke, respectively (p > .05). CONCLUSION: Results from our pilot study demonstrated the safety and feasibility of LAAE concomitant with LIS LVAD as a stroke prevention strategy. This is the first prospective study describing LAAE performed concomitantly to less invasive LVAD implantation. The efficacy of LAAE in long-term stroke prevention needs to be confirmed in future prospective randomized clinical trials.

Mitochondrial ATP Synthase Tetramer Disassembly following Blood-Based or del Nido Cardioplegia during Neonatal Cardiac Surgery.

Conservation of mitochondrial adenosine triphosphate (ATP) synthase proteins during ischemia is critical to preserve ATP supply and ventricular function. Following myocardial ischemia in adults, higher order ATP synthase tetramer proteins disassemble into simpler monomer units, reducing the efficiency of ATP production. However, it is unknown if myocardial ischemia following the use of cardioplegia results in tetramer disassembly in neonates, and whether it can be mitigated by cardioplegia if it does occur. We investigated myocardial ATP synthase tetramer disassembly in both a neonatal lamb cardiac surgery model and in neonatal children requiring cardiac surgery for the repair of congenital heart disease. Neonatal lambs (Ovis aries) were placed on cardiopulmonary bypass (CPB) and underwent cardioplegic arrest using a single dose of 30 mL/kg antegrade blood-based potassium cardioplegia (n = 4) or a single dose of 30 mL/kg antegrade del Nido cardioplegia (n = 6). Right ventricular biopsies were taken at baseline on CPB (n = 10) and after approximately 60 minutes of cardioplegic arrest before the cross clamp was released (n = 10). Human right ventricular biopsies (n = 3) were taken following 40.0 ± 23.1 minutes of ischemia after a single dose of antegrade blood-based cardioplegia. Protein complexes were separated on clear native gels and the tetramer to monomer ratio quantified. From the neonatal lamb model regardless of the cardioplegia strategy, the tetramer:monomer ratio decreased significantly during ischemia from baseline measurements (.6 ± .2 vs. .5 ± .1; p = .03). The del Nido solution better preserved the tetramer:monomer ratio when compared to the blood-based cardioplegia (Blood .4 ± .1 vs. del Nido .5 ± .1; p = .05). The tetramer:monomer ratio following the use of blood-based cardioplegia in humans aligned with the lamb data (tetramer:monomer .5 ± .2). These initial results suggest that despite cardioprotection, ischemia during neonatal cardiac surgery results in tetramer disassembly which may be limited when using the del Nido solution.

Direct right ventricular Impella LD implantation enables postoperative ambulation and may avoid sternal re-entry.

Right ventricular assist devices (RVADs) typically require groin cannulation or sternal re-entry which can be avoided by direct pulmonary artery implantation with an Impella. We report the first use of the Impella LD as a directly implanted RVAD.

Neurodevelopmental Delay After the Neonatal Repair of Coarctation and Arch Obstruction.

BACKGROUND: Although single ventricle physiology and cyanosis are known risk factors for neurodevelopmental delay (NDD), the impacts of isolated coarctation (Iso CoA) repair or arch reconstruction (AR) are less understood. METHODS: The Vineland Adaptive Behavior Scales, third edition, prospectively evaluated children without a genetic syndrome. An overall composite score, normalized to age and sex, was generated from individual domain scores. NDD was defined as a composite or domain score at least 1 SD less than the established mean. Iso CoA was repaired using a left thoracotomy, whereas AR was performed using a sternotomy and cardiopulmonary bypass. Children with a structurally normal heart and without previous surgery were used as control patients. RESULTS: Of 60 children, 50 required neonatal repair (12 for Iso CoA, 38 for AR), and 10 were control patients. From the entire cohort of children who required neonatal coarctation repair (Iso CoA + AR) composite (93.9 ± 15.9 vs 105.0 ± 7.4; P = .004) and all domain scores were significantly lower than control patients. NDD was present in 25 of 50 children after repair and in 0 of 10 control patients (P = .003). Similarly, the prevalence of NDD was significantly greater after Iso CoA repair (58.3% vs 0%; P = .005) and AR (47.3% vs 0%; P = .007) than in the control population, but no significant difference was found between the Iso CoA and AR groups (P = .74). CONCLUSIONS: In this small cohort, half of the neonates who required either Iso CoA repair or AR exhibit NDD at an intermediate-term follow-up.

Met-Hemoglobin Is a Biomarker for Poor Oxygen Delivery in Infants Following Surgical Palliation.

BACKGROUND: Infants with cyanotic congenital heart disease demonstrate wide fluctuations in hemoglobin (Hb), oxygen saturation, and cardiac output following palliation. Methemoglobin (Met-Hb), the product of Hb oxidation, may represent a compensatory mechanism during hypoxia and may be utilized as a biomarker. METHODS: Arterial and venous Met-Hb levels were obtained from infants requiring palliation. The primary outcome was to describe the relationship between Met-Hb and other indices of tissue oxygenation (venous saturation, estimated arteriovenous oxygen difference [Est AV-Diff], and lactate). Secondary outcomes were to determine the impact of elevated Met-Hb levels ≥1.0% and the effect of red blood cell (RBC) transfusion on Met-Hb levels. RESULTS: Fifty infants and 465 Met-Hb values were studied. Venous Met-Hb levels were significantly higher than arterial levels (venous: 0.84% ± 0.36% vs arterial: 0.45% ± 0.18%; P < .001). Venous Met-Hb demonstrated a significant inverse relationship with venous oxygen saturation (R = -0.6; P < .001) and Hb (R = -0.3, P < .001) and a direct relationship with the Est AV-Diff (R = 0.3, P < .001). A total of 129 (29.6%) venous Met-Hb values were elevated (≥1.0%) and were associated with significantly lower Hb and venous saturation levels and higher Est AV-Diff and lactate levels. Methemoglobin levels decreased significantly following 65 RBC transfusions (0.94 ± 0.40 vs 0.77 ± 0.34; P < .001). Linear mixed models demonstrated that higher venous Met-Hb levels were associated with lower measures of tissue oxygenation and not related to any preoperative clinical differences. CONCLUSION: Methemoglobin may be a clinically useful marker of tissue oxygenation in infants following surgical palliation.

Serial Follow-Up of Two Surgical Strategies for the Repair of Tetralogy of Fallot.

Adverse events following tetralogy of Fallot repair include arrhythmia, reoperation, and death. While limiting the right ventriculotomy mitigates these events over the short and intermediate term, the impact over the long term is unknown. Children requiring tetralogy of Fallot repair were divided into 2 groups: extended right ventriculotomy vs limited right ventriculotomy with transatrial ventricular septal defect closure. Follow-up office ECGs and Holter monitoring, exercise stress tests, and echocardiograms were obtained in the first, second, and third postoperative decades. The primary outcome was cumulative events defined as reoperation, arrhythmia, or death. The extended and limited right ventriculotomy techniques were used in 21 and 17 children, respectively. Cumulative survival was 93.6% at 30 years and was not different between groups. While 10-year (42.9% vs 5.9%, P = 0.02) event rates favored the limited ventriculotomy technique, there were no significant differences at 20 or 25 years. Cox proportional hazard analysis demonstrated that the limited ventriculotomy technique was independently associated with lower events at 10 years (hazard ratio 0.03, 95% confidence interval 0.0016, 0.5697, P = 0.01). The limited ventriculotomy group had greater exercise capacity in the second decade but not the third. Right ventricular end-diastolic diameter Z score was not different at 10 or 20 years, but was significantly smaller in the limited ventriculotomy group at 30 years (5.55 ± 1.69 vs 4.14 ± 0.63, P = 0.03). Limiting the right ventriculotomy during tetralogy of Fallot repair limits 10-year events, improves exercise capacity at 20 years, and attenuates late right ventricular dilation.

Damus-Kaye-Stansel procedure avoids coronary obstruction in complex D-transposition.

Although all coronary anatomy in D-transposition of the great arteries may be "switchable," there are reports in the literature of early and late coronary obstruction following the arterial switch operation. The Damus-Kaye-Stansel procedure does not risk injury to the coronary arteries, and unlike the atrial switch, commits the left ventricle to the systemic circulation. We present a series of four neonates over 22 years with D-transposition of the great arteries and a concomitant coronary artery anomaly precluding arterial switch that were repaired using a Damus-Kaye-Stansel procedure and right ventricle to pulmonary artery conduit.

Modified Repair of Type I and II Truncus Arteriosus Limits Early Right Ventricular Outflow Tract Reoperation.

Repair of truncus arteriosus often requires early right ventricular outflow tract (RVOT) reoperation. Using a modified repair, the branch pulmonary arteries are left in situ, which may avoid earlier RVOT reoperation. We hypothesized that our modified repair for type I and II truncus arteriosus would extend the time to RVOT reoperation. Infants with truncus arteriosus were divided into 2 groups: (1) traditional technique where the branch pulmonary arteries are excised from the truncal root, or (2) modified repair where the branch pulmonary arteries are left in situ and septated from the truncal root. Regardless of the approach, a bioprosthetic conduit or homograft was used to establish right ventricular to pulmonary artery continuity. Follow-up pulmonary artery angiograms were used to assess for branch pulmonary artery stenosis. From 54 infants (modified repair: 33, traditional technique: 21), there were no significant differences in age at repair, gender, or type of truncus arteriosus. With 100% follow-up, use of the modified repair resulted in a lower rate of branch pulmonary artery stenosis, and greater freedom from surgical branch pulmonary arterioplasty. Five- and 10-year freedom from RVOT reoperation (5 years: modified-81.5% vs traditional-30.5%, P = 0.004; 10 years: modified-53.3% vs traditional-30.5%, P = 0.01) favored the modified repair. Cox regression analysis demonstrated that the modified repair was associated with an independently lower risk for RVOT reoperation (hazard ratio: 0.08, confidence interval: 0.01, 0.75, P = 0.02). Thus, maintaining the branch pulmonary artery architecture resulted in greater freedom from RVOT reoperation.

Use of a Dacron Annular Sparing Versus Limited Transannular Patch With Nominal Pulmonary Annular Expansion in Infants With Tetralogy of Fallot.

BACKGROUND: Repair of tetralogy of Fallot (ToF) using a transannular patch can result in severe pulmonary insufficiency (PI) and subsequent right ventricular (RV) dilation. Use of a Dacron (Maquet Cardiovascular LLC, Wayne, NJ) limited transannular patch with nominal pulmonary annular expansion (LTAP) attempts to limit PI. We sought to evaluate the degree of PI and RV dilation resulting from a LTAP or annular sparing (AS) approach. METHODS: Infants less than 1 year of age undergoing ToF repair between 2000 and 2010 were divided into 2 groups: LTAP and AS RV outflow tract patch. Echocardiograms were used to determine RV dimensions and corresponding Z-values. RESULTS: From 94 infants, 48 required a LTAP and 46 required an AS patch. The preoperative pulmonary valve annulus Z-value was significantly smaller in the LTAP versus AS group (-2.7 ± 1.4 versus -0.9 ± 1.5; p < 0.001). Mean follow-up was obtained at 7.9 ± 3.4 years. Ten-year freedom from severe pulmonary insufficiency was 78.5% versus 93.2% (p = 0.3) in the LTAP and AS groups, respectively. There was no significant difference in the diameter of the RV base Z-value between groups (LTAP: 0.9 ± 0.8 versus AS: 0.0 ± 2.3; p = 0.1). Further, the freedom from reoperation at 10 years was also not significantly different between the LTAP and AS groups (95.6% versus 91.8%; p = 0.5). CONCLUSIONS: When required, a LTAP results in a similar change in RV chamber size and rate of reoperation at an intermediate-term follow-up.