Talha Niaz

Prevalence and outcome of thrombotic and embolic complications in adults after Fontan operation

Background There are limited studies of thrombotic and embolic complications (TEC) in the adult Fontan population. The purpose of the study was to determine the prevalence, risk factors, and outcomes of TECs in this population. Methods Retrospective review of adults with a previous Fontan operation, with follow‐up at Mayo Clinic, 1994‐2014. Systemic TEC was defined as intracardiac thrombus, ischemic stroke, or systemic arterial embolus. Nonsystemic TEC was defined as Fontan conduit/right atrial thrombus or pulmonary embolus. Results We identified 387 patients with a mean (SD) age of 28 (7) years and a mean follow‐up of 8 (2) years. An atriopulmonary connection (APC) was done for 286 patients (74%). Atrial arrhythmias were present in 278 (72%). There were 121 TECs (systemic n = 36, nonsystemic n = 85) in 98 patients (25%). Risk factors for systemic TEC were atrial arrhythmia (hazard ratio 2.28, P = .001) and APC (hazard ratio 1.98, P = .02); nonsystemic TEC also had similar risk factors. All 98 patients received warfarin. Warfarin was discontinued in 10 of 98 because of bleeding, and 8 of these 10 subsequently had a second TEC. Among the 82 patients who had follow‐up imaging, 16 (20%) had resolution of thrombus. In total, 24 of 98 patients had a second TEC, most of whom had inadequate anticoagulation. Conclusions Thrombotic and embolic complication was not uncommon; risk factors for TEC were APC and atrial arrhythmias. Most patients were treated successfully with warfarin alone. A second TEC occurred in most patients whose anticoagulation was discontinued because of bleeding events.

When is the right time for Fontan conversion? The role of cardiopulmonary exercise test

BACKGROUND To determine if Fontan conversion (FC) resulted in improvement in exercise capacity (EC), and to determine the role of cardiopulmonary exercise test (CPET) in risk stratification of patients undergoing FC. METHODS A retrospective review of patients who underwent CPET prior to FC at Mayo Clinic from 1994 to 2014. The patients who also underwent post-operative CPET were selected for the analysis of improvement in EC defined as 10% increase in baseline peak oxygen consumption (VO2). RESULTS 75 patients CPET prior to FC; mean age 24±6years; 44 males (59%); and 51 (68%) were in NYHA III/IV prior to FC. Pre-operative peak VO2 was 15.5±3.4ml/kg/min. A comparison of pre- and post-FC CPET data was performed using 42 patients (56%) that underwent CPET after FC. Improvement in EC occurred in 18 of 42 patients (43%). Baseline peak VO2 >14ml/kg/min was associated with improved EC (hazard ratio [HR] 1.85; P=.02). Improvement in New York Heart Association (NYHA) class occurred in 12 (67%) patients with improved EC vs 2 (8%) without improved EC. Improvement in NYHA class was more likely to occur in patients with improved EC compared to those without improvement EC (odds ratio 4.11, P=.01). There were 10 (13%) perioperative deaths, and baseline peak VO2 ≤14ml/kg/min was predictive of perioperative mortality (HR 3.74; P<.001). CONCLUSIONS Baseline peak VO2 was predictive of perioperative survival, and improvement in EC. Performance on CPET in failing Fontan patients might be a useful clinical parameter in determining appropriate timing of FC.

Outcomes in adult Fontan patients with atrial tachyarrhythmias

Background The optimal management strategy for atrial tachyarrhythmia in the Fontan population is unknown. Methods Retrospective review of 264 adult Fontan patients with atrial tachyarrhythmia evaluating 3 clinically adopted scenarios: antiarrhythmic drug (AAD) therapy, catheter ablation (CA), and Fontan conversion (FC). These patients were followed up at Mayo Clinic from 1994 to 2014. The study objective was to compare freedom from atrial tachyarrhythmia recurrence (AR) and occurrence of composite adverse events (stroke, heart failure hospitalization, death, or heart transplant) between treatment groups. Results The age of atrial tachyarrhythmia onset was 25 ± 4 years, time from Fontan operation was 13 ± 6 years, follow‐up was 74 ± 18 months, atriopulmonary Fontan was 215 (81%), and atrial flutter/intra‐atrial reentry tachycardia was 173 (65%). In those managed with AAD (n = 110), freedom from AR was 7% at 60 months. Catheter ablation (n = 31) was associated with an acute procedural success of 94%, and freedom from AR was 41% at 60 months. Fontan conversion (n = 33) resulted in a perioperative mortality of 3%, and freedom from AR was 51% at 60 months. Fontan conversion and CA were similar with regard to AR (P = .14) and significantly better compared with AAD (P < .0001). Adverse events were found to occur more frequently in the patients with AR (P < .0001) and the patients treated with AAD only (P < .0001). Conclusions Catheter ablation and FC operations are associated with less recurrence of atrial tachyarrhythmia compared with AAD. Atrial tachyarrhythmias are more likely to recur in patients with a longer history of the arrhythmia and are associated with more adverse events. Early referral to a specialty center for these interventions should be considered.

Outcome of direct current cardioversion for atrial arrhythmia in adult Fontan patients

BACKGROUND Limited data are available about direct current cardioversion (DCCV) in Fontan patients. METHODS Retrospective review of adult Fontan patients that underwent DCCV for atrial arrhythmias at Mayo Clinic, 1994-2014. Study endpoints were to determine procedural success, safety, and the freedom from arrhythmia recurrence after DCCV. Procedural success was defined as termination of the presenting atrial arrhythmia prior to leaving the cardioversion suite. RESULTS 86 patients underwent 152 DCCV; age 27 ± 8 years; male 49 (57%); atriopulmonary Fontan, 64 (74%); atrial flutter/interatrial reentry tachycardia 125 (82%). Freedom from recurrence was 84% and 47% at 12 and 36 months; freedom from repeat DCCV was 91% and 64% at 12 and 36 months. Procedural failure occurred in 41 (27%); predictors of procedural failure were older age (HR 1.91, CI 1.16-2.73 per decade) and prior DCCV (HR 2.71, CI 1.22-3.21). Concomitant oral class I or III antiarrhythmic medication was associated with an increased likelihood of success (HR 0.64, CI 0.41-0.87). Predictors of recurrence were older age (HR 3.26, CI 1.19-6.55 per decade); duration of arrhythmia (HR 1.87, CI 1.14-2.56 per decade); and presence of atriopulmonary Fontan (HR 1.54, CI 1.27-1.85). Procedural complications were symptomatic bradycardia in 2 cases (1%). No thromboembolic complications or deaths occurred. CONCLUSION DCCV in Fontan patients is safe but is associated with significant procedural failure and recurrence rates. Ideally, antiarrhythmic medication should be instituted prior to DCCV in stable patients and DCCV alone should be considered as a temporizing measure to maintain sinus rhythm.

Incidence, morphology, and progression of bicuspid aortic valve in pediatric and young adult subjects with coexisting congenital heart defects

BACKGROUND Bicuspid aortic valve (BAV) occurs both as an isolated cardiac lesion and in association with congenital heart defects (CHD). Their aim was to identify the incidence and morphology of BAV in patients with coexisting CHD and compare their disease progression to patients with isolated BAV. METHODS The Mayo Clinic echocardiography database was retrospectively analyzed to identify pediatric and young adult patients (≤22 years) who were diagnosed with BAV from 1990 to 2015. The morphology of BAV was determined from the echocardiographic studies before any intervention. RESULTS Overall, 1010 patients with BAV were identified, 619 (61%) with isolated BAV and 391 (39%) with BAV and coexisting CHD. The incidence of BAV was highest in patients with coarctation of the aorta (36%) and interrupted aortic arch (36%). In comparison to patients with isolated BAV, patients with BAV and left-sided obstructive lesions more frequently had right-left cusp fusion (P = .0001). BAV in patients with right-sided obstructive lesions was rare, but they more frequently had right-noncoronary or left-noncoronary cusp fusion (P = .01). No significant progression of aortic stenosis or regurgitation was observed in patients with BAV and coexisting CHD; however in patients with isolated BAV the severity of aortic regurgitation increased with age. In patients with isolated BAV, the ascending aorta diameter (z-score) increased with age, peaked around 8-9 years of age, and was larger in comparison to patients with BAV and coexisting CHD. The sinus of Valsalva diameter (z-score) in patients with BAV and ventricular septal defect was larger than isolated BAV patients after 18 years (P < .04). CONCLUSIONS The morphology of BAV, the pattern and progression of aortic dilatation, and the severity of aortic valve disease vary in pediatric and young adult patients with BAV and coexisting CHD. However, there was no significant BAV disease progression when associated with these CHD.

Improved Ventricular Function after TEE-guided Cardioversion of Atrial Arrhythmias in Patients after the Fontan Operation

OBJECTIVE Atrial tachyarrhythmias frequently develop after the Fontan operation. Patients with Fontan physiology rely on atrial contribution to cardiac output, and thus control of atrial arrhythmias is important. Outcomes after cardioversion in patients after Fontan have not been reported. We sought to determine if cardioversion results in improved echocardiographic parameters or clinical symptomatology; and, discern risk factors for arrhythmia recurrence. DESIGN We retrospectively analyzed the Mayo Clinic echocardiographic database to capture patients after the Fontan operation who underwent transesophageal echocardiography-guided electrical cardioversion from 2000-2015. Clinical and echocardiographic data were collected and compared at baseline and follow-up. RESULTS Eight hundred ninety patients with prior Fontan operation underwent echocardiographic evaluation; 341 (38%) developed atrial arrhythmias. Thirty-six patients [20 males, median age 29 (12-51)] underwent transesophageal echocardiography-guided cardioversion of atrial arrhythmias [atrial flutter/intraatrial reentrant tachycardia (75%); atrial fibrillation (25%)]. At follow-up, improvements were noted in ejection fraction by 10% (P < .0001); atrioventricular valve regurgitation grade (39%) (P = .002); New York Heart Association (NYHA) class (61%) (P < .001); and resolution of spontaneous echo contrast in the Fontan circuit (65%) (P < .01). No embolic events occurred following cardioversion. Eighteen patients (50%) developed recurrent atrial arrhythmias at 15 (3-36) months after cardioversion. Five-year freedom from arrhythmia recurrence was 61%. Significant univariate predictors of arrhythmia recurrence were atrial flutter/intraatrial reentrant tachycardia (HR = 4.3, P = .02); NYHA ≥ II (HR = 4.1, P = .03); systemic right ventricle (HR = 5.2; P = .02); and ejection fraction ≤ 40% (HR = 2.8; P = .04). On multivariate analysis, only systemic right ventricle (HR = 3.7; P = .02) remained an independent predictor of arrhythmia recurrence. CONCLUSION After the Fontan operation, cardioversion of atrial arrhythmias improves ventricular function, atrioventricular valve regurgitation grade, and NYHA class. Arrhythmia recurrence was common and patients with atrial flutter/intraatrial reentrant tachycardia, systemic right ventricle, or reduced ventricular function may be at risk of arrhythmia recurrence. Further studies are required to identify additional risk factors and protective factors for arrhythmia recurrence.

INCIDENCE AND CLINICAL PRESENTATION OF KOMMERELL DIVERTICULUM AND ANEURYSM

There are limited data on incidence of Kommerell diverticulum (KD) and aneurysm (KA). We aimed to report the incidence and clinical presentation of KD and KA; and determine risk factors for development of KA. The Mayo Clinic radiology database was retrospectively analyzed to identify pts with

IMPACT OF FONTAN CONVERSION ON EXERCISE CAPACITY IN ADULT FONTAN PATIENTS

There are no data evaluating the impact of Fontan conversion (FC) on exercise capacity (EC) as measured by cardiopulmonary exercise test (CPET). Retrospective study comparing CPET performed pre and post FC at Mayo Clinic, 1994-2014. Only symptom-limited maximal exercise CPET performed within 24

OUTCOMES FOR SURGICAL REPAIR OF KOMMERREL DIVERTICULUM AND ANEURYSM

Standard surgical management of Kommerell diverticulum (KD) and Kommerell aneurysm (KA) has not been established. We aimed to report our outcomes for surgical repair of KD and KA. The Mayo Clinic surgery database was retrospectively analyzed to identify pts with aberrant subclavian artery (ASA)