Alexander C. Egbe

Bioprosthetic Valve Thrombosis Versus Structural Failure: Clinical and Echocardiographic Predictors.

BACKGROUND Bioprosthetic valve thrombosis (BPVT) is considered uncommon; this may be related to the fact that it is often unrecognized. Recent data suggest that BPVT responds to vitamin K antagonists, emphasizing the need for reliable diagnosis. OBJECTIVES This study sought to determine the diagnostic features of BPVT and to formulate a diagnostic model for BPVT. METHODS Cases of BPVT occurring between 1997 and 2013 were identified from the Mayo Clinic pathology database. Patients with BPVT were matched 1:2 for age, sex, and prosthesis position with patients whose valves were explanted for structural failure. We formulated a diagnostic model for BPVT using multivariate linear logistic regression and receiver operating characteristic. RESULTS Among 397 consecutive cases of explanted bioprostheses, there were 46 cases of BPVT (11.6%; aortic 29, mitral 9, tricuspid 7, pulmonary 1), mean age was 63 years, and 68% were male. Thirty (65%) cases occurred >12 months post-implantation; median bioprosthetic valve longevity was 24 months (cases) versus 108 months (controls) (p < 0.001). Independent predictors of BPVT were >50% increase in mean echo-Doppler gradient from baseline within 5 years (odds ratio [OR]: 12.7), paroxysmal atrial fibrillation (OR: 5.19), subtherapeutic international normalized ratio (OR: 7.37), increased cusp thickness (OR: 12.2), and abnormal cusp mobility (OR: 6.94). Presence of all 5 diagnostic features was predictive of BPVT with 76% sensitivity, 93% specificity, 85% positive predictive value, and 89% negative predictive value (p < 0.001). CONCLUSIONS BPVT is not uncommon and can occur several years after surgery. A combination of clinical and echocardiographic features can reliably diagnose BPVT.

Mixed aortic valve disease: midterm outcome and predictors of adverse events

AIMS The aim of this article is to determine freedom from adverse events (AE) defined as symptoms, aortic valve replacement (AVR), or death in the mixed aortic valve disease (MAVD) population. METHODS AND RESULTS We reviewed patients with moderate/severe MAVD followed at Mayo Clinic from 1994-2013. Only asymptomatic patients with normal ejection fraction and trileaflet aortic valve were included. Cox proportional-hazard models and Kaplan-Meier method were used. We identified 213 patients with moderate/severe MAVD; mean age was 69 years (±11) and 67% were males. An AE endpoint was reached in 172 patients, and 69% of these AEs occurred in moderate MAVD (peak velocity of 3-3.9 m/s). Mean follow-up was 10.1 ± 3 years, and mean time to AE was 2.9 ± 2.1 years. A mechanical prosthesis was implanted in 71/151 (47%), and 54/151 (36%) had concomitant coronary artery bypass grafting and/or aorta replacement during AVR. Early surgical mortality was 0.7%. Freedom from AE endpoint was 42% [confidence interval (CI) 39-45%] and 30% (CI 27-33%) at 3 and 5 years, respectively. Predictors of AE were peak aortic velocity [hazard ratio (HR) 2.73; CI 1.97-2.84, P < 0.0001] for every 1 m/s difference and having severe stenosis or severe regurgitation at presentation (HR 2.58; CI 2.01-4.44, P = 0.001). CONCLUSION Moderate MAVD had high rate of AEs comparable to severe isolated aortic stenosis and should be followed as such. Patients with severe MAVD should be evaluated at least every 6 months because half of them will become symptomatic and require AVR within 1 year.

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.

Transcatheter closure of postmyocardial infarction, iatrogenic, and postoperative ventricular septal defects: The Mayo Clinic experience.

To determine event‐free survival after transcatheter closure of ventricular septal defect (VSD), and to identify predictors of adverse events (AE) in post myocardial infarction VSD (post‐MI VSD) subgroup.

Cardiopulmonary exercise test in adults with prior Fontan operation: The prognostic value of serial testing

BACKGROUND The purpose of the study was to determine the role of cardiopulmonary exercise test (CPET) indices in predicting cardiovascular adverse events (CAEs) in patients with Fontan palliation. CAE was defined as death or cardiac surgery. METHODS Retrospective review of adult Fontan patients who had treadmill CPET at Mayo Clinic, 1994-2013. Patients with loss of follow-up defined as ≥2years without clinical follow-up were excluded. The results of serial CPETs were reviewed, and patients with CPETs meeting the following criteria were selected for analysis: maximum effort on serial CPETs, minimum of 3-year interval between CPETs, and absence of CAE between CPETs. RESULTS A total of 145 patients met inclusion criteria for the study; age at baseline CPET was 24±3years; age at Fontan operation was 11±5years; and 91 (63%) were males. Baseline peak oxygen consumption (VO2) was 22.7±5.4ml/kg/min (63±11% predicted), peak heart rate was 135±31beats per minute, and oxygen saturation at peak exercise was 86±7%. Serial CPETs were performed in 71/145 patients (49%); mean duration between CPETs was 3.8±0.3years. The % predicted peak VO2 decreased by 1.7±0.9 percentage points/year. CAE (deaths n=22; cardiac surgery n=45) occurred in 54/145 patients (37%) within 8±3years. Decline in % predicted peak VO2≥3 percentage points/year was the only predictor of 5-year risk of CAE (HR 1.86, 95% CI 1.11-3.48, P=0.02). CONCLUSIONS Serial CPET is prognostic of CAE in the adult Fontan population, and can be used to risk stratify these patients.

Bioprosthetic valve thrombosis: What we know and what we need to know.

Bioprosthetic valve thrombosis account for 11% of all reoperations for bioprosthetic valve dysfunction, and preoperative diagnosis can be made based on echocardiographic features. Early reoperation can be prevented if BPVT is identified and treated preoperatively.

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.

Prevalence and predictors of intracranial aneurysms in patients with bicuspid aortic valve

Objective To determine the prevalence and outcomes of intracranial aneurysm (IA) in patients with bicuspid aortic valve (BAV). Methods Retrospective review of patients with BAV who underwent brain MR angiography at the Mayo Clinic from 1994 to 2013. Results There were 678 patients included in this study—mean age 57±13 years, men 480 (71%), mean follow-up 10±3 years (5913 patient-years). Coarctation of aorta (COA) was present in 154 (23%) patients. There were 59 IAs identified in 52 of 678 patients (7.7%). IA was present in 20/154 patients (12.9%) with COA and 32/524 patients (5.7%) without COA (p<0.001). For the patients without COA, female gender and right–left cusp fusion were risks factors for IA in women after adjustment for all potential variables (HR 1.76, CI 1.31 to 2.68, p=0.03). There was no significant trend in the risk for IA across age tertiles: age ≤40 years versus 41–60 years (HR 1.19, p=0.34), and age 41–60 years versus 61–80 years (HR 1.06, p=0.56). Among the 52 patients with IA, enlargement occurred in three patients (6%), rupture in two patients (4%) and four patients (8%) underwent coil embolisation. For the 626 patients without IA at baseline, no patient developed IA over 7±2 years of imaging follow-up. Conclusions BAV is associated with a higher prevalence of IA compared to the general population, and this risk is higher in patients with COA, right–left cusp fusion and female gender.