Native Aortic Root Research Articles

Native aortic root thrombus leading to myocardial infarction in a single ventricle patient.

We report a 14-month-old male with hypoplastic left heart syndrome, mitral stenosis, and aortic stenosis with native aortic root thrombus. He developed a wide complex ventricular tachycardia and ST-segment elevation myocardial infarction with troponin I levels peaking at 388 ng/mL. He was treated safely with systemic alteplase with a resolution of his regional wall motion abnormality 18 hours later.

Aortic Arch Reconstruction in the Norwood Procedure: The “Reimplantation” Technique

Arch reconstruction as part of the Norwood Procedure is a challenging three-dimensional task that has to combine the aortic and pulmonary roots in a Damus-Kaye-Stansel anastomosis and also reconstruct the hypoplastic aortic arch, usually with concomitant coarctation. Compression or torsion of the aortic root can compromise coronary blood flow, especially in the setting of a diminutive native aortic root. This technique focuses on maximum augmentation of the aortic root with separate implantation of the pulmonary root into the reconstructed aortic arch – this maintains the natural spatial relationship of the aortic and pulmonary roots. The technique has the advantage of being reproducible across all morphological variants in hypoplastic left heart syndrome as well as in other situations where the Norwood is used such as with transposed great arteries and interrupted aortic arch.

Intermediate-term Outcomes Following a Case Series of Reoperations for Medtronic Freestyle Stentless Aortic Valves

BackgroundData are limited on long-term outcomes in patients who have undergone a reoperation following failure of a stentless aortic valve. MethodsBetween 2006 and 2016, a retrospective analysis was performed on 24 patients who underwent open aortic valve replacement surgery for a failed stentless aortic valve prosthesis at Health Sciences North, Sudbury, Ontario, Canada. The primary outcome was a low mortality rate from cardiac-related deaths after 5 years. ResultsAll patients underwent insertion of a Medtronic Freestyle bioprosthesis (Minneapolis, MN) implanted using the modified subcoronary technique for their initial operation. The interval from the first operation to the stentless redo surgery ranged from 6 to 13 years. Aortic valve reoperation was performed for structural valve deterioration in 96% (n = 23) of the cases. Reoperations involved a removal of the stented valve leaflets and standard aortic valve replacement within the stentless casing in 20% (n = 5) of the cases, with the remaining cases requiring complete removal of the stentless prosthesis and aortic valve replacement. In those in whom a complete removal of the stentless valve was possible (n = 19), no disruption of the native aortic root occurred, with a 0% rate of conversion to a Bentall procedure. No intraoperative mortality occurred. The 30-day and 10-year operative mortality rates were 4% and 16%, respectively. ConclusionsRedo surgery for failing stentless valves can be done with relatively low risk and with acceptable long-term outcomes without resorting to root-replacement techniques.

Mitral annular disjunction on cardiac MRI: Prevalence and association with disease severity in Loeys-Dietz syndrome

BackgroundThe purpose of this study was to evaluate mitral annular disjunction (MAD) on cardiac magnetic resonance imaging (MRI) in Loeys-Dietz Syndrome (LDS) and to explore its association with adverse outcomes. MethodsIn this retrospective cohort study, adult patients with LDS who underwent cardiac MRI were evaluated for MAD, aortic dimensions, and ventricular volumetry. Aortic events were defined as aortic surgery and/or dissection and severe arrhythmic events as cardiac arrest or sustained ventricular tachycardia (VT). ResultsAmong 46 LDS patients (52% female, 37.2 ± 14.3 years), 17 had MAD (37%). MAD and no MAD groups were similar in age, sex, aortic dimensions and left ventricular parameters. After a clinical follow-up of 4.3 years (IQR 1.5–8.4), 3 in MAD and 4 in no MAD groups required aortic valve sparing root replacement (VSRR) and 1 in MAD developed type A dissection. Over a similar imaging follow-up period [4.1 years (IQR 2.7–9.1) vs. 3.2 years (IQR 1.0–9.0), p = 0.65], compared to baseline, increase in native aortic root size was significant only in MAD (39.4 ± 4.6 mm vs. 38.1 ± 5.3 mm, p = 0.02, 19.3 ± 2.4 mm/m2 vs. 18.7 ± 2.4 mm/m2, p = 0.01) compared to those without MAD. Patients with MAD were younger at first aortic event compared to those without (26.7 ± 11.5 years vs. 45.0 ± 14.9 years, p = 0.03). MAD distance correlated with need for VSRR, r = 0.57, p = 0.02. Two patients in the MAD group developed sustained VT. No cardiac arrest or death was observed. ConclusionMAD is highly prevalent in LDS, associated with progressive aortic dilatation, and aortic events at younger age. MAD may be a marker of disease severity necessitating close surveillance.

Nanocarriers of shRNA-Runx2 directed to collagen IV as a nanotherapeutic system to target calcific aortic valve disease.

Runx2 is a key transcription factor involved in valvular interstitial cells (VIC) osteodifferentiation, a process actively entwined with the calcific aortic valve disease (CAVD). We hypothesize that a strategy intended to silence Runx2 could be a valuable novel therapeutic option for CAVD. To this intent, we aimed at (i) developing targeted nanoparticles for efficient delivery of short hairpin (sh)RNA sequences specific for Runx2 to the aortic valve employing a relevant mouse model for CAVD and (ii) investigate their therapeutic potential in osteoblast-differentiated VIC (oVIC) cultivated into a 3D scaffold. Since collagen IV was used as a target, a peptide that binds specifically to collagen IV (Cp) was conjugated to the surface of lipopolyplexes encapsulating shRNA-Runx2 (Cp-LPP/shRunx2). The results showed that Cp-LPP/shRunx2 were (i) cytocompatible; (ii) efficiently taken up by 3D-cultured oVIC; (iii) diminished the osteodifferentiation of human VIC (cultured in a 3D hydrogel-derived from native aortic root) by reducing osteogenic molecules expression, alkaline phosphatase activity, and calcium concentration; and (iv) were recruited in aortic valve leaflets in a murine model of atherosclerosis. Taken together, these data recommend Cp-LPP/shRunx2 as a novel targeted nanotherapy to block the progression of CAVD, with a good perspective to be introduced in practical use.

Novel Expansible Aortic Annuloplasty Ring Exhibits Similar Characteristics as the Dacron Ring-an In Vitro Evaluation.

An increasing body of research indicates that annular stability plays a key role for a successful aortic valve repair. The aim of this study was to evaluate and compare a novel open aortic annuloplasty ring (the A-ring) with the Dacron ring. Both rings were compared with native aortic roots in vitro. Eighteen aortic roots were included in the study and randomized into three groups: the native, Dacron, and A-ring group. The roots were evaluated in an in vitro physiologic pulsatile model simulating the left side of the heart. Aortic annulus diameters were significantly reduced both in the Dacron ring group (p = 0.003) and the A-ring group (p = 0.020) when compared with the native group. Both the Dacron ring and A-ring effectively downsized the aortic annulus diameter. The A-ring also displayed an ability to maintain aortic root distensibility during the cardiac cycle equally to the Dacron ring.

Comparison of outcomes between aortic root replacement and supra-coronary interposition graft for type A aortic dissection: A retrospective case series.

The decision to conserve or replace the native aortic valve following acute type-A aortic dissection (ATAAD) is an area of cardiac surgery without standardized practice. This single-center retrospective study analysed the long-term performance of the native aortic valve and root following surgery for ATAAD. Between 2009 and 2018 all cases ATAAD treated at Royal Brompton and Harefield NHS Foundation Trust were analysed. Patients were divided into two groups: (a) ascending aorta (interposition) graft (AAG) without valve replacement and (b) nonvalve-sparing aortic root replacement (ARR). Preoperative covariates were compared, as well as operative characteristics and postoperative complications. Long-term survival and echocardiographic outcomes were analysed using regression analysis. In total, 116 patients were included: 63 patients in the AAG group and 53 patients in the ARR group. In patients where the native aortic valve was conserved, nine developed severe aortic regurgitation and two patients developed dilation of the aortic root requiring subsequent replacement during the follow-up period. Aortic regurgitation at presentation was not found to be associated with subsequent risk of developing severe aortic regurgitation or reintervention on the aortic valve. Overall mortality was observed to be significantly lower in patients undergoing AAG (17.5% vs. 41.5%, p = .004). With careful patient selection, the native aortic root shows good long-term durability both in terms of valve competence and stable root dimensions after surgery for ATAAD. This study supports the consideration of conservation of the aortic valve during emergency surgery for type-A dissection, in the absence of a definitive indication for root replacement, including in cases where aortic regurgitation complicates the presentation.

Spontaneous thrombus formation in native aortic root in patients with hypoplastic left heart syndrome: clinical presentation, treatment, and outcomes.

We report a neonate who presented with spontaneous thrombus formation in the native aortic root after Norwood palliation for hypoplastic left heart syndrome. Thrombus formation led to myocardial ischaemia due to decreased coronary blood flow with electrocardiographic signs of ischaemia and elevated cardiac enzymes. Aggressive thrombolysis and anticoagulation therapy were major contributors to successful outcome.

Native Aortic Root Thrombosis in Single-Ventricle Patients with Native-to-Neoaortic Anastomoses.

In single-ventricle patients with native-to-neoaortic anastomoses, the native aortic root serves as a conduit to the coronary arteries. Thrombosis of the native aortic root has been described only in small, limited reports. We described our center's experience with this rare adverse event. All single-ventricle patients who underwent native-to-neoaortic anastomosis from 2002 to 2017 were compiled from institutional databases. Chart review identified cases of native aortic root thrombosis. Of 467 patients, there were 9 (2%) cases of native aortic root thrombosis; all had hypoplastic left heart syndrome. Timing of thrombosis varied and occurred following each stage of single-ventricle palliation. For treatment, 8 patients received systemic anticoagulation and one patient did not receive any treatment. One patient also underwent percutaneous thrombectomy. Three patients (33.3%) died during the follow-up period. Among survivors, 4/6 had right ventricular systolic function that was mildly depressed or worse at a median follow-up of 8.3years (interquartile range 1.3-10.8). Native aortic root thrombosis is a rare complication occurring at various stages of single-ventricle palliation. In this series, 6 of 9 patients (66.6%) survived; however, ventricular function was often compromised. No risk factors were identified to focus preventative therapies.

The Ross Procedure With the Inclusion Technique

The Ross procedure is superior as a valve substitute in children and early adulthood because of its clear survival benefits. The free standing-root implantation is associated with failure of the autograft and inclusion techniques that support externally the autograft warrants its longevity. The current technique consists in the implantation of the autograft within the native aortic root thereby both supporting the autograft and avoiding any coronary distortion.

Hemiarch replacement with aortic root preservation for acute type A aortic dissection

: Acute Type A aortic dissection (TAAD) is a surgical emergency requiring expeditious management. The surgical principles involve restoration of true lumen blood flow with obliteration of the primary tear thereby mitigating malperfusion and restoring valvular competency. At our institution 60% of TAAD patients are treated with a hemiarch and the other 40% are treated with a total arch replacement (TAR). All cases employ the use of cerebral protection. For hemiarch replacement, retrograde cerebral perfusion (RCP), via the superior vena cava (SVC), is utilized. Antegrade cerebral perfusion is utilized via brachiocephalic vessels during a TAR. Electroencephalogram (EEG) and somatosensory evoked potentials (SSEP) are used for neurocerebral monitoring with the aim of electrical silence before circulatory arrest. Key radiographic and clinical findings are used to adjudicate between these two procedures pre and intraoperatively. Patients with any of the following undergo a TAR at our institution: (I) aortic arch aneurysm, (II) primary or re-entry tear in the aortic arch or proximal descending aorta, (III) circumferential dissection of the aortic arch, or (IV) carotid body dissection or thrombosis. Irrespective of the procedure chosen, central aortic cannulation is routinely performed via modified Seldinger technique with transesophageal echocardiography guidance. The proximal aorta is addressed while the patient is systemically cooled to hypothermia. All effort is made to retain the native aortic root and valve where possible. However, in cases where the aortic root is dilated or has a tear, a valve sparing root replacement or a modified Bentall is performed. The operative strategy for a TAAD at our institution is predicated on a tear-based paradigm. However, the extent of aortic reconstruction may be different based on surgeon and center experience.

Ascending aorta and aortic root replacement in an infant: a case report

We herein report the first clinical case of prosthetic replacement of the ascending aorta and aortic arch to repair a giant aneurysm in a 7-month-old child. The ascending aorta and arch replacement to the level of left subclavian artery was performed using a no. 16 Polymaille prosthesis, the brachiocephalic trunk was reimplanted into the vascular prosthesis and the kinked section of the left common carotid artery was removed, followed by reimplanting the left common carotid artery into the left subclavian artery. First, proximal anastomosis with the vascular prosthesis was created using a no. 16 Polymaille prosthesis and the vascular suture was strengthened with a Teflon strip. During circulatory arrest, the aortic arch was crossed between the orifice of the left common carotid artery and left subclavian artery, with the cut extended to the isthmus region along the small curvature of the arch. The brachiocephalic trunk was aligned and brought down, with subsequent implantation into the ascending aorta prosthesis 2 cm below the initial fixation point. In the final stage, the kinked section of the left common carotid artery was resected and the aligned left carotid artery was directly reimplanted into the left subclavian artery using end-to-side anastomosis. The patient developed tracheobronchitis and moderate heart failure during the postoperative period. The duration of mechanical ventilation was 16 hours. Infusion and antibacterial therapy were discontinued on postoperative day 8. On postoperative day 13, the patient was discharged and referred to the outpatient centre for further treatment and rehabilitation. A sufficiently large-sized prosthesis allows for further development in paediatric patients. This is facilitated by the preservation of the native aortic root with restored valve function and the formation of a bevelled distal anastomosis with a small unchanged aortic section in the isthmus region, which maintains growth potential. This first reported case of an infant demonstrates the possibility of combination interventions on the aortic arch and brachiocephalic artery during the first year of life.Received 30 January 2021. Revised 24 March 2021. Accepted 29 March 2021.Funding: The study did not have sponsorship.Conflict of interest: The authors declare no conflicts of interests.Contribution of the authors: The authors contributed equally to this article.

High Glucose Induced Changes in Human VEC Phenotype in a 3D Hydrogel Derived From Cell-Free Native Aortic Root.

Background: Valvular endothelial cells (VEC) have key roles in maintaining valvular integrity and homeostasis, and dysfunctional VEC are the initiators and major contributors to aortic valve disease in diabetes. Previous studies have shown that HG stimulated an inflammatory phenotype in VEC. Inflammation was shown to induce endothelial to mesenchymal transition (EndMT), a process extensively involved in many pathologies, including calcification of the aortic valve. However, the effect of HG on EndMT in VEC is not known. In addition, there is evidence that endothelin (ET) is a proinflammatory agent in early diabetes and was detected in aortic stenosis, but it is not known whether HG induces ET and endothelin receptors and whether endothelin modulates HG-dependent inflammation in VEC. This study aims to evaluate HG effects on EndMT, on endothelin and endothelin receptors induction in VEC and their role in HG induced VEC inflammation.Methods and Results: We developed a new 3D model of the aortic valve consisting of a hydrogel derived from a decellularized extracellular cell matrix obtained from porcine aortic root and human valvular cells. VEC were cultured on the hydrogel surface and VIC within the hydrogel, and the resulted 3D construct was exposed to high glucose (HG) conditions. VEC from the 3D construct exposed to HG exhibited: attenuated intercellular junctions and an abundance of intermediate filaments (ultrastructural analysis), decreased expression of endothelial markers CD31 and VE–cadherin and increased expression of the mesenchymal markers α-SMA and vimentin (qPCR and immunocytochemistry), increased expression of inflammatory molecules ET-1 and its receptors ET-A and ET-B, ICAM-1, VCAM-1 (qPCR and Immunocytochemistry) and augmented adhesiveness. Blockade of ET-1 receptors, ET-A and ET-B reduced secretion of inflammatory biomarkers IL-1β and MCP-1 (ELISA assay).Conclusions: This study demonstrates that HG induces EndMT in VEC and indicates endothelin as a possible target to reduce HG-induced inflammation in VEC.

The Characteristics and Outcomes of Native Aortic Valve Thrombosis: A Systematic Review

BackgroundThere is a lack of knowledge in the current medical literature about native aortic valve thrombosis. ObjectivesThe aim of this systematic review was to summarize the characteristics, presentations, underlying etiologies, and outcomes of native aortic valve thrombosis and to present a meta-analysis of the best available data. MethodsThe authors performed a literature search, identified published cases of patients with native aortic valve thrombosis, and pooled the data in this meta-analysis. The statistical analysis included calculations of the prevalence of the various presentations, underlying etiologies, aortic cusp involvement, as well as choices of diagnostic testing. They calculated the sensitivities of the various diagnostic testing as well as in-hospital mortality event rates and the univariate ORs of the risk factors for poor outcomes. ResultsThe search strategy and screening process yielded 74 cases of native aortic valve thrombosis, which are included in this meta-analysis. The data revealed that the most common presentation was myocardial infarction in 36%, and the most common underlying etiology was hypercoagulable state in 30%. In-hospital clinical deterioration after presentation including recurrent embolism occurred in ∼38%, and in-hospital mortality rate was ∼20%. ConclusionsNative aortic valve thrombosis is clinically relevant, especially in patients presenting with embolic events. Awareness about native aortic valve or root thrombosis as well as its underlying etiologies, diagnostic work-up, and management is essential, because this condition can be associated with poor outcomes.

Technical Modifications That Might Improve Long-term Outcomes of the Ross Procedure in Children

BackgroundFailure of the pulmonary valve autograft (PVA) after the Ross procedure (RP) has discouraged its widespread use and has led to modifications or alternatives to the procedure. We sought to analyze whether certain technical modifications could improve results of the RP in children. MethodsSixty-nine patients (median age, 12 years; range, 0.25-17.9) underwent the RP between January 1996 and December 2018. A concomitant Konno procedure was performed on 20 of 69 patients (29%). Prior interventions included balloon valvuloplasty in 30 (44%) and/or surgical valvuloplasty in 39 (57%). Technical modifications included using the native aortic root for external annuloplasty, implanting the autograft using uniplanar horizontal sutures through the aortic wall, normalizing the sinotubular junction, and wrapping the native root remnant around the PVA. ResultsOperative mortality was 1 of 69 patients (1.5%), with no late deaths. No patient had neoaortic valvar stenosis and 7 of 68 (10%) had mild regurgitation on discharge echocardiogram. At latest follow-up (median, 9.4 years; range, 0.4-21.3) there was no significant change in Z scores of annulus, sinus, or sinotubular junction diameters when compared with those at discharge. Three patients (4.4%) required late autograft replacement, 2 PVA repair, and 2 resection of a pseudoaneurysm. Actuarial freedom from PVA replacement was 87% at 20 years. Freedom from right ventricular outflow tract catheter reintervention or reoperation was 83% and 80%, respectively. ConclusionsTechnical modifications of the RP used in this cohort might successfully prolong the life of the PVA without compromising its growth, an important advantage in pediatric patients.

Coronary Artery Aneurysms in Patients With Marfan Syndrome: Frequent, Progressive, and Relevant

BackgroundThere are few data on the prevalence and clinical consequences of coronary artery aneurysms (CAAs) in adult patients with Marfan syndrome (MFS). MethodsWe performed a retrospective cohort study of 109 patients with pathogenic variants in the FBN1 gene. Diameters of the left main coronary artery (LMCA) and right- coronary artery (RCA) were measured by computed tomography angiography. ResultsThe overall prevalence of CAA was 46%. The prevalence rates of CAA were 18% and 68% in patients with a native aortic root (group 1) and patients with previous aortic-root replacement (group 2), respectively. Previous aortic dissection or aortic intervention, longer time from aortic-root replacement, higher systemic score, significant mitral valve involvement, and diffuse aortic disease were correlated with CAA. During a mean follow-up of 8.5 ± 7.6 years, 4 patients developed pseudoaneurysms of the coronary anastomoses, requiring surgery. ConclusionsCAAs are common in adult patients with MFS and are associated with a more severe aortic phenotype and a longer follow-up after aortic-root replacement. Our study demonstrates that coronary artery size should be regularly followed, mostly after aortic-root replacement and in patients with severe aortic phenotypes. Large multicentre studies are warranted to elucidate the most appropriate surveillance plan.

Fabrication and in-vitro characterization of a polymeric aortic valve for minimally invasive valve replacement

The valve replacement therapy is the standard treatment for severe heart valve diseases. Nowadays, two types of commercial prosthesis are available: mechanical and biological, but both of them have severe limitations. Moreover, alternative therapeutic approach for valve replacement, based on minimally invasive techniques (MIAVR), motivates the search for new valve materials. In this study a polyurethane-based self-expandable tri-leaflets heart valve compatible with MIAVR procedure is proposed. The device is based on the development, fabrication and characterization of three different elements: the leaflets, the polymeric stent for supporting the leaflets, and the external metallic stent for anchoring the valve to the native aortic root. The polymeric stent and the valve leaflets were fabricated using a thermoplastic silicone-polycarbonate-urethane using 3D printing and spray technology while the external metallic stent was made in nickel titanium (Nitinol) to obtain a self-expandable valve after the crimping process. The three elements were assembled in the completed device and tested by crimping, fatigue and fluid-dynamic test. The novel polymeric valve proposed showed promising results about valve crimping capabilities, durability and fluid dynamic performances. This approach could offer advantages such as low cost and to produce a tailor-made device basing on patient's imaging data. Moreover, the selected biomaterial offers the potential to have a device that could need of permanent anticoagulation and lack of calcification.

In Vitro Evaluation of Flow Distribution in All-Region Perfusion during the Norwood Operation

Continuous all-region perfusion has the potential to reduce total body ischemia during the Norwood procedure. This technique involves placing cannulas in the innominate artery, descending aorta, and native aortic root, thus providing continuous flow to the whole body at mild hypothermia (32–34°C) during the entire operation. However, the cannulation strategy in this approach must be optimized to achieve adequate flow rates to all vascular beds. To ensure appropriate blood flow rates to three cannulas of different caliber supplied by two inflow pumps, a benchtop evaluation of comparative flow rates through branched cannulas with variable independent perfusion pressures was conducted. Two isolated vertical columns with outlets at 10 mmHg intervals to allow for adjustable perfusion pressures were filled with expired banked packed red blood cells and fresh frozen plasma. The main arterial line was bifurcated with an 8-Fr arterial cannula inserted at the base of one column and a 4-mm (outside diameter [OD]) olive tip cannula inserted at the base of the other column. Flow rates were measured on each branch of the ¼″ arterial lines. Under experimental cardiopulmonary bypass (CPB) perfusion pressures of 30–50 mmHg on the 8-Fr arterial cannula column, the branched olive tip cannula accommodated less than 25% of total flow at total flow rates of 50–700 mL/min. This fraction is insufficient to sustain adequate lower body perfusion. However, the olive tip flow fraction was found to be sufficient for coronary blood flow (5–20 mL/kg/min) when olive tip perfusion pressures close to average neonatal diastolic blood pressures (20–60 mmHg) were tested. For all-region perfusion during the Norwood operation, primary CPB arterial flow should be divided to the head and coronary circulation with an independent pump delivering flow to the descending aorta. This should avoid cerebral over-circulation and insufficient flow to the lower body.

In Vitro Evaluation of Flow Distribution in All-Region Perfusion during the Norwood Operation.

Continuous all-region perfusion has the potential to reduce total body ischemia during the Norwood procedure. This technique involves placing cannulas in the innominate artery, descending aorta, and native aortic root, thus providing continuous flow to the whole body at mild hypothermia (32-34°C) during the entire operation. However, the cannulation strategy in this approach must be optimized to achieve adequate flow rates to all vascular beds. To ensure appropriate blood flow rates to three cannulas of different caliber supplied by two inflow pumps, a benchtop evaluation of comparative flow rates through branched cannulas with variable independent perfusion pressures was conducted. Two isolated vertical columns with outlets at 10 mmHg intervals to allow for adjustable perfusion pressures were filled with expired banked packed red blood cells and fresh frozen plasma. The main arterial line was bifurcated with an 8-Fr arterial cannula inserted at the base of one column and a 4-mm (outside diameter [OD]) olive tip cannula inserted at the base of the other column. Flow rates were measured on each branch of the ¼″ arterial lines. Under experimental cardiopulmonary bypass (CPB) perfusion pressures of 30-50 mmHg on the 8-Fr arterial cannula column, the branched olive tip cannula accommodated less than 25% of total flow at total flow rates of 50-700 mL/min. This fraction is insufficient to sustain adequate lower body perfusion. However, the olive tip flow fraction was found to be sufficient for coronary blood flow (5-20 mL/kg/min) when olive tip perfusion pressures close to average neonatal diastolic blood pressures (20-60 mmHg) were tested. For all-region perfusion during the Norwood operation, primary CPB arterial flow should be divided to the head and coronary circulation with an independent pump delivering flow to the descending aorta. This should avoid cerebral over-circulation and insufficient flow to the lower body.

Life-Threatening But Forgotten Complication After Norwood Operation

Native aortic root thrombosis (NART) after Norwood operation for hypoplastic left heart syndrome (HLHS) is a complication that has only rarely been reported. In this issue of The Annals of Thoracic Surgery, Rajab and Mitchell1 reported 4 cases of NART. A systematic literature search identified 12 publications with 16 cases previously reported. In addition to these 12 publications, there was 1 abstract with 9 cases of NART from University of Michigan in 2018.2