Wilson W. Lam

Clinical outcomes after ventricular assist device implantation in adults with complex congenital heart disease

BACKGROUND There are minimal data regarding ventricular assist device (VAD) implantation in adult patients with complex congenital heart disease (CHD). METHODS The medical records of 6 adult patients with complex CHD who underwent VAD implantation were retrospectively analyzed to characterize pre-operative clinical status, implantation techniques and challenges, post-operative management, and post-operative outcomes. RESULTS All patients had a systemic right ventricle, including 2 with single-ventricle physiology. The average age at VAD implantation was 41 years. The implanted VADs included 1 HeartMate XVE, 3 HeartMate II (Thoratec Corp, Pleasanton, CA), 1 Jarvik 2000 (Jarvik Heart, New York, NY), and 1 HeartWare HVAD (HeartWare Inc, Framingham, MA). In-hospital outcomes included no sub-pulmonic ventricular failure, no VAD thrombosis or mechanical failure, 30-day mortality in 1 patient, non-fatal sub-arachnoid hemorrhage in 1 patient, and sustained ventricular tachycardia requiring unsynchronized direct current cardioversion in 1 patient. Of the 5 patients who survived to discharge, 1 patient received 171 days of VAD support before cardiac transplantation and survived for 1,484 days after transplantation; 1 patient received 262 days of VAD support before out-of-hospital death of unknown etiology; 1 patient had received VAD support for 988 days as of December 1, 2012, while awaiting a transplant; and 2 patients who received VADs as destination therapy had received 577 and 493 days of VAD support, respectively, and were still alive as of December 1, 2012. CONCLUSIONS This case series characterizes important post-operative management challenges and clinical outcomes associated with VAD implantation as a bridge-to-transplant or as destination therapy in adult patients with complex CHD.

Plasma Exchange for Urgent Apixaban Reversal in a Case of Hemorrhagic Tamponade after Pacemaker Implantation

We report the case of an 82-year-old man in whom hemorrhagic pericardial effusion occurred one week after pacemaker implantation, while he was taking apixaban. Few therapies exist for reversing the anti-Xa effect of apixaban. To reverse anticoagulation, our patient underwent plasma exchange, which facilitated pericardiocentesis and prevented possible surgical intervention. To our knowledge, this is the first report of the use of plasmapheresis to reverse the anticoagulant effect of apixaban.

A review of sensitivity, specificity, and likelihood ratios: evaluating the utility of the electrocardiogram as a screening tool in hypertrophic cardiomyopathy.

Appropriate interpretation of a screening tests validity poses a challenge to the clinician. The purpose of this review is to revisit the terms sensitivity, specificity, likelihood ratio, and pre- and posttest probability and their application to the clinical setting. For illustration, we use a recently published article in the American Journal of Cardiology that investigates the false negative rate of electrocardiograms in athletic preparticipation screening for hypertrophic cardiomyopathy.

LONG-TERM FOLLOW-UP IN ADULT SURVIVORS OF PULMONARY ATRESIA WITH INTACT VENTRICULAR SEPTUM

Background: Early childhood palliation for pulmonary atresia with intact ventricular septum (PA-IVS) can range from biventricular repair to single ventricle palliation. This study aims to evaluate the need for additional interventions long-term in a survivor cohort of adult PA-IVS patients following

Atriopulmonary Fontan Spontaneous Echo Contrast Improved after Cardioversion

A 21-year-old woman with tricuspid atresia who had undergone an atriopulmonary Fontan operation at 3 years of age presented with intra-atrial reentrant tachycardia and tachycardia-induced cardiomyopathy. She had done well on no medications, and systolic function was normal on echocardiograms 3 months before this presentation. Since then, she had experienced exertional palpitations, increasing abdominal girth, loose bowel movements, vague abdominal pain, fatigue, and decreased appetite. Examination revealed a blood pressure of 120/70 mmHg, a regular tachycardic pulse, clear lungs, a pulse oximetry saturation of 97%, and a distended abdomen with ascites and hepatomegaly. Laboratory tests showed elevated alanine transaminase of 115 IU/L, brain natriuretic peptide of 556 pg/mL, an international normalized ratio of 1.4, negative stool antitrypsin (no protein-losing enteropathy), and normal renal function, lactate, and cardiac enzyme levels. An electrocardiogram showed flutter waves and 2:1 atrioventricular conduction (ventricular rate, 122 beats/min) (Fig. 1). A transthoracic echocardiogram revealed a dilated left ventricle with severely depressed systolic function, an ejection fraction of 0.25, and spontaneous echo contrast in the dilated inferior vena cava. A transesophageal echocardiogram showed no left atrial appendage thrombus; however, dense contrast was present in the dilated right atrium of the Fontan circuit (Fig. 2). Fig. 1 A 12-lead electrocardiogram shows intra-atrial reentrant tachycardia with 2:1 atrioventricular block; arrows point to flutter waves. Fig. 2 Transesophageal echocardiogram (bicaval view) shows 2:1 intra-atrial reentrant tachycardia with dense spontaneous echo contrast. We presumed that tachycardia-induced cardiomyopathy was exacerbating the patients Fontan circuit stasis, so we recommended terminating the tachycardia. Cardioversion yielded improvement (Fig. 3); however, contrast was still seen on cardiac magnetic resonance images (Figs. 4 and ​and5).5). The patient was placed on amiodarone, anticoagulation, and anticongestive therapy. An echocardiogram 4 months later showed improvement; the patient had mildly depressed systolic function with maintained sinus rhythm. Fig. 3 Transesophageal echocardiogram (bicaval view) after cardioversion to sinus rhythm shows improved but persistent spontaneous echo contrast. Fig. 4 Cardiac magnetic resonance image (axial view) shows atriopulmonary Fontan anatomy (right atrium-to-bilateral branch pulmonary artery anastomoses with visible contrast). Fig. 5 Cardiac magnetic resonance image (bicaval coronal view) shows the atriopulmonary Fontan circuit with swirling spontaneous echo contrast. IVC = inferior vena cava; LA = left atrium; RA = right atrium/atriopulmonary Fontan circuit to pulmonary arteries; ...

Therapeutic Plasma Exchange for Urgent Rivaroxaban Reversal

Direct oral anticoagulants, which include the factor Xa inhibitor rivaroxaban, have some advantages over vitamin K antagonists in regard to stroke prevention in patients with atrial fibrillation. However, no antidotes to reverse the effect of oral anticoagulants are commercially available, which can complicate treating patients in whom reversal is urgent. We faced this challenge in a kidney transplant candidate, a 65-year-old man with end-stage renal disease who had been taking rivaroxaban for paroxysmal atrial fibrillation. When a deceased-donor kidney became available, we needed to rapidly reduce the patients bleeding risk, while minimizing the cold ischemic time of the donor kidney. Therefore, we decided to take an experimental approach and perform therapeutic plasma exchange. The patients plasma anti-factor Xa level decreased from 0.4 IU/mL immediately before treatment to 0.21 IU/mL afterward, indicating that rivaroxaban had been actively removed from circulation. Waste fluid showed significant anti-Xa activity, indicating that the risk of rebound anticoagulation had been mitigated. The patient subsequently underwent successful kidney transplantation. To our knowledge, this is the first report of therapeutic plasma exchange to reverse the effects of rivaroxaban in a patient undergoing urgent surgery. This treatment may also be suitable for patients who have life-threatening, large-volume bleeding, especially in the presence of substantial kidney or liver dysfunction.

Complex Left Atrial Appendage Morphology Is an Independent Risk Factor for Cryptogenic Ischemic Stroke

Importance: Ischemic strokes pose a significant health burden. However, the etiology of between 20 and 40% of these events remains unknown. Left atrial appendage morphology may influence the occurrence of thromboembolic events. Design: A retrospective cross-sectional study was conducted to investigate the role of LAA morphology in patients with atrial fibrillation (AF) and cardioembolic-associated stroke and patients with cryptogenic stroke without atrial fibrillation. LAA morphology is classified into two groups: (1) simple (chicken-wing) vs. (2) complex (non-chicken wing) based on transesophageal echocardiography (TEE) findings. In addition to the LAA morphology, left atrial parameters, including orifice diameter, depth, emptying velocity, and filling velocity, were collected for both groups. Mathematical, computational models were constructed to investigate flow velocities in chicken-wing and non-chicken wing morphological patterns to assess LAA function further. Findings: TEE values for volume, size, emptying, and filling velocities were similar between simple and complex LAA morphology groups. Patients with cryptogenic stroke without coexisting AF were noted to have significantly higher rates of complex LAA morphology. Chicken-wing LAA morphology was associated with four-fold higher flow rate (kg/s) in computational simulations. Conclusions: Complex LAA morphology may be an independent contributing factor for cryptogenic strokes. Further studies are warranted to investigate the mechanism involved in LAA morphology and thromboembolic events.

USE OF NOVEL ORAL ANTICOAGULANTS IN ADULT FONTAN PATIENTS

Background: Thromboembolic complications are a leading cause of morbidity and mortality in patients with Fontan physiology. Current clinical practice for prevention and treatment of these complications involves the use of vitamin K antagonists and/or antiplatelet agents. Novel oral anticoagulants (

Analysis of adults with congenital heart disease presenting to pediatric emergency departments with arrhythmias

OBJECTIVE As survivors of congenital heart disease (CHD) continue to age, healthcare utilization by this population has increased. It is unknown how often these patients utilize the emergency department (ED) at childrens hospitals and how arrhythmias play a role in their utilization of care. DESIGN Using a retrospective cohort design, the Pediatric Hospital Information System (PHIS) database was investigated and we studied adults (≥18 years) with CHD (ACHD) who presented to pediatric EDs from 2004 to 2014. SETTING Tertiary care pediatric hospitals. RESULTS Of the 6310 encounters to pediatric EDs, 1594 (25%) were for arrhythmias. The median age was 21 years (IQR 19.1-25.1). The most common tachyarrhythmia diagnoses during the study period were atrial flutter (32%), atrial fibrillation (15%), and paroxysmal VT (10%). Bradyarrhythmias represented a minority of total arrhythmias. Presentation with arrhythmias was associated with an increased risk of admission, ICU care, and death (P < .01). Arrhythmias are also highly associated with CHD severity with twice as many complex CHD having arrhythmias compared to simple CHD (P < .01). CONCLUSIONS Total admissions of adults with CHD from the ED of childrens hospitals have increased over time while the transfers to outside facilities remain consistently low. While the population of ACHD continues to grow, utilization of pediatric EDs for this cohort has increased. Adults with higher CHD complexity are more likely to present with clinical arrhythmias but there is a growing number of ACHD patients with simple complexity presenting with arrhythmias in recent years. ACHD patients that present with arrhythmias are at increased risk of morbidity and mortality.

Pulmonary Valvular Stenosis in L-Transposition of the Great Arteries with Ventricular Septal Defect

A 39-year-old man presented with a fever of 102 °F. He had a history of viridans group streptococci (VGS) bacteremia, levo-transposition of the great vessels (also known as congenitally corrected transposition), large peri-membranous ventricular septal defect (VSD), and valvular pulmonary stenosis. Prior cardiac catheterization had shown his circulation to be well balanced, with a ratio of pulmonary blood flow to systemic blood flow of 1.4:1. Examination revealed nothing unusual except for a harsh systolic ejection murmur along the left sternal border. No emboli or immunologic phenomena were seen. The patients white blood cell count and cell count differential were normal, but his erythrocyte sedimentation rate and C-reactive protein level were elevated. During his initial 48 hours after presentation, 8 of 8 blood cultures grew VGS. We performed transesophageal echocardiography (TEE) to look for valvular vegetations and found neither intracardiac vegetations nor other evidence of endocarditis. Depicted are atrial–ventricular discordance (Fig. 1); ventriculo–arterial discordance (Figs. 2 and ​and3);3); short-axis view of the semilunar valves (Figs. 4 and ​and5);5); 3-dimensional (3D) imaging of the domed unicommissural pulmonic valve (Fig. 6); and a peak gradient of 80 mmHg, which suggests protected pulmonary arterial pressures (Fig. 7). Fig. 1 Transesophageal echocardiogram (0° midesophageal view) depicts a 4-chamber view. Note the usual arrangement of the atria, with atrioventricular discordance and the large inlet ventricular septal defect. Fig. 2 Transesophageal echocardiogram (60° midesophageal view) depicts atrioventricular and ventriculoarterial discordance between the left atrium, right ventricle, and aorta. Fig. 3 Transesophageal echocardiogram (60° midesophageal view) depicts atrioventricular and ventriculoarterial discordance between the right atrium, left ventricle, and pulmonary artery. Fig. 4 Transesophageal echocardiogram (140° midesophageal view) depicts short-axis view across the semilunar valves caudally. The aorta is anterior and leftward (L-transposition) to the pulmonary valve. Fig. 5 Transesophageal echocardiogram (140° midesophageal view) depicts short-axis view across the semilunar valves cranially. The pulmonary valve appears to be bicommissural, stenotic, thickened, and domed. Fig. 6 Three-dimensional transesophageal echocardiogram (140° midesophageal view) depicts short-axis view and level of pulmonary stenosis. The pulmonary valve is clearly unicommissural. Fig. 7 Continuous-wave Doppler echocardiogram across the pulmonary valve depicts an 80-mmHg gradient (4.5 m/s peak velocity) in the setting of systemic right ventricular and protected pulmonary arterial pressures. In Figure 1, the atrioventricular (AV) valves appear to be in the same plane, which raises the possibility of a partial AV canal with a large inlet VSD—rather than the usual apical displacement of the tricuspid valve (not shown) seen in structurally normal hearts and in congenitally corrected transposition. Also note that the AV valves follow their respective ventricles (Figs. 1–3), not their supplying atria. In comparing planar (Figs. 4 and ​and5)5) with 3D imaging (Fig. 6), note that the “bicommissural” valve is better defined with 3D imaging as unicommissural.