Mechanism for temporal changes in exercise capacity after Fontan palliation: Role of Doppler echocardiography

BACKGROUND

The objective was to better understand Doppler hemodynamics and exercise capacity in patients with Fontan palliation by delineating the hemodynamic mechanism for temporal changes in their peak oxygen consumption (V̇o₂).

METHODS

We performed a retrospective review of adult Fontan patients with systemic left ventricle (LV) who underwent serial transthoracic echocardiograms (TTE) and cardiopulmonary exercise tests (CPET) at Mayo Clinic in 2000-2015. TTE and CPET data were used (1) to determine agreement between V̇o₂ and Doppler-derived LV function indices (eg, stroke volume index [SVI] and cardiac index [CI]) and (2) to determine agreement between temporal changes in peak V̇o₂ and LV function indices.

RESULTS

Seventy-five patients (44 men; 59%) underwent 191 pairs of TTE and CPET. At baseline, mean age was 24±3 years, peak V̇o₂ was 22.9±4.1 mL/kg/min (63±11 percent predicted), SVI was 43±15 mL/m², and CI was 2.9±0.9 L/min/m². Peak V̇o₂ correlated with SVI (r=0.30, P<.001) and with CI (r=0.45, P<.001) in the 153 pairs of TTE and CPET in patients without cirrhosis. Temporal changes in percent predicted peak V̇o₂ correlated with changes in SVI (r=0.48, P=.005) and CI (r=0.49, P=.004) among the 33 patients without interventions during the study. In the 19 patients with Fontan conversion, percent predicted peak V̇o₂ and chronotropic index improved.

CONCLUSIONS

Overall, there was a temporal decline in peak V̇o₂ that correlated with decline in Doppler SVI. In the patients who had Fontan conversion operation, there was a temporal improvement in peak V̇o₂ that correlated with improvement in chronotropic index.

Outcomes of cardiac pacing in adult patients after a Fontan operation

BACKGROUND

Cardiac pacing can be challenging after a Fontan operation, and limited data exist regarding pacing in adult Fontan patients. The objectives of our study were to determine risk factors for pacing and occurrence of device-related complications (DRCs) and pacemaker reinterventions.

METHODS

We performed a retrospective review of Fontan patients from 1994 through 2014. We defined DRCs as lead failure, lead recall, cardiac perforation, lead thrombus/vegetation, or device-related infection, and cardiovascular adverse events (CAEs) as venous thrombosis, stroke, death, or heart transplant. Pacemaker reintervention was defined as lead failure or recall.

RESULTS

Of 439 patients, 166 (38%) had pacemakers implanted (79 during childhood; 87, adulthood); 114 patients (69%) received epicardial leads initially, and 52 (31%), endocardial leads. Pacing was initially atrial in 52 patients (31%); ventricular, 30 (18%); or dual chamber, 84 (51%). There were 37 reinterventions (1.9% per year) and 48 DRCs (2.4% per year). Pacemaker implantation during childhood was a risk factor for DRCs (hazard ratio, 2.01 [CI, 1.22-5.63]; P = .03). There were 70 CAEs (venous thrombosis, 5; stroke, 11; transplant, 8; and death, 46), yielding a rate of 3.5% per year. DRCs, CAEs, and reintervention rates were comparable for patients with epicardial or endocardial leads.

CONCLUSIONS

More than one-third of adult Fontan patients referred to Mayo Clinic had pacemaker implantation. Epicardial leads were associated with high rate of pacemaker reinterventions but similar DRC rates in comparison to endocardial leads.

Outcomes in Moderate Mixed Aortic Valve Disease: Is it Time for a Paradigm Shift?

BACKGROUND

A direct comparison of outcomes between moderate mixed aortic valve disease (MAVD) and isolated aortic stenosis (AS) or aortic regurgitation (AR) has not been performed, making evidence-based recommendations difficult in patients with MAVD.

OBJECTIVES

This study sought to determine adverse event (AE) occurrence (the primary endpoint), defined as New York Heart Association functional class III/IV symptoms, aortic valve replacement, or cardiac death, and to compare AE rates between MAVD and isolated AS or AR.

METHODS

Asymptomatic patients were identified with moderate MAVD and an ejection fraction ≥50% and were followed at Mayo Clinic from 1994 to 2013. Moderate MAVD was defined as a combination of moderate AS and moderate AR. Age- and sex-matched control groups were selected with isolated moderate AR (n = 117), moderate AS (n = 117), or severe AS (n = 117).

RESULTS

At 9.1 ± 4.2 years of follow-up, patients with moderate MAVD (n = 251) had a mean age of 63 ± 11 years, 73% were male, and 38% had bicuspid valve. AE occurred in 193 (77%) patients in this group, including symptom development (69%), aortic valve replacement (67%), and cardiac death (4%). Predictors of AE were older age (hazard ratio [HR]: 1.71 per decade; 95% confidence interval [CI]: 1.38 to 1.97 per decade; p = 0.001), and relative wall thickness >0.42 (HR: 2.01; 95% CI: 1.86 to 2.33; p = 0.002). AE rates were similar in the MAVD and severe AS group (71% vs. 68% at 5 years; p = 0.49), but were significantly higher compared with the moderate AS and AR groups.

CONCLUSIONS

MAVD patients had outcomes comparable to those with severe AS, and preserved ejection fraction and should be monitored closely for symptoms.

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.

Management of Pregnancy in Patients With Complex Congenital Heart Disease: A Scientific Statement for Healthcare Professionals From the American Heart Association

Today, most female children born with congenital heart disease will reach childbearing age. For many women with complex congenital heart disease, carrying a pregnancy carries a moderate to high risk for both the mother and her fetus. Many such women, however, do not have access to adult congenital heart disease tertiary centers with experienced reproductive programs. Therefore, it is important that all practitioners who will be managing these women have current information not only on preconception counseling and diagnostic evaluation to determine maternal and fetal risk but also on how to manage them once they are pregnant and when to refer them to a regional center with expertise in pregnancy management.

Amiodarone-induced thyrotoxicosis in adults with congenital heart disease--clinical presentation and response to therapy

OBJECTIVE

The development of amiodarone-induced thyrotoxicosis (AIT) can threaten the hemodynamic stability of adult patients with congenital heart disease (CHD). Here, we describe the natural history and treatment response of AIT in this at-risk population.

METHODS

We studied retrospectively all cases of AIT that occurred in CHD patients at our institution after a minimum of 3 months on amiodarone. Subjects were identified from the cohort of adults with CHD who were treated at the Mayo Clinic Adult CHD clinic between 1987 and 2009.

RESULTS

We identified 23 cases of AIT: 7 were type 1, 13 were type 2, and 3 were undefined due to insufficient data. Most patients were symptomatic (17 of 23, 74%), with arrhythmia and weight loss as the most common symptoms. The majority (12 of 23, 52%) were initially observed; 10 patients (43%) were treated medically and 1 patient (5%) underwent thyroidectomy. Four patients from the observation group eventually required active treatment and 3 patients from the medical group required surgery. Asymptomatic patients tended to resolve under observation (5 of 7, 71.4%) rather than progress to active treatment (0 of 4) (P = .06). Discontinuation of amiodarone, AIT type, or use of perchlorate did not impact AIT duration.

CONCLUSION

AIT in CHD patients exhibits a wide range of severity and sensitivity to medical therapy. Asymptomatic patients display a trend toward AIT resolution with observation alone. Amiodarone continuation does not appear to impact management outcome or disease duration. Additional studies in this high-risk population could identify elements of pathophysiology that would point toward better disease prevention and treatment.

Bicuspid and Unicuspid Aortic Valve: Fate of Moderate/Severe Mixed Aortic Valve Disease

OBJECTIVES

There is a paucity of data about mixed aortic valve disease (MAVD) in patients with bicuspid/unicuspid aortic valve (BAV). This study sought to describe the outcomes of patients with moderate/severe MAVD.

METHODS

We queried our database for patients with BAV and moderate/severe MAVD seen between 1994 and 2013. We excluded patients with baseline New York Heart Association (NYHA) III/IV symptoms, left ventricular ejection fraction <50%, aortic dimension >50 mm, and significant disease of other valves. The purpose of the study was to determine the freedom from NYHA III/IV symptoms and aortic valve replacement (AVR).

RESULTS

We identified 138 patients with moderate/severe MAVD; mean age was 51 ± 12 years; 112 (81%) were males; and follow-up was 8.5 ± 4 years. Ninety-two patients (67%) underwent AVR within 3.7 ± 2.5 years. Mechanical prostheses were implanted in 73 patients (79%); 22 patients (26%) and 36 patients (39%) had concomitant coronary artery bypass graft and aorta replacement during AVR respectively. There were no surgical deaths. Freedom from AVR was 84%, 51%, and 20% at 1, 5 and 10 years respectively. Predictors of AVR were age at presentation (hazard ratio [HR] 5.22; confidence interval [CI] 3.10 to 6.64) for every decade increase in age; and having severe stenosis or regurgitation at the time of presentation (HR 1.32; CI 1.05 to 3.16).

CONCLUSIONS

Age and disease severity should be incorporated in the risk assessment of BAV patients with MAVD, and patients with both risk factors should be monitored closely.

Right Parasternal Lead Placement Increases Eligibility for Subcutaneous Implantable Cardioverter Defibrillator Therapy in Adults With Congenital Heart Disease

BACKGROUND

The subcutaneous implantable cardioverter defibrillator (S-ICD) provides an attractive option for patients with congenital heart disease (CHD) in whom a transvenous defibrillator is contraindicated. Given the unusual cardiac anatomy and repolarization strain, the surface electrocardiogram (ECG) is frequently abnormal, potentially increasing the screen failure rate.

METHODS AND RESULTS

We prospectively screened 100 adult CHD patients regardless of the presence of clinical indication for ICD utilizing a standard left sternal lead placement, as well as a right parasternal position. Baseline patient and 12-lead ECG characteristics were examined to assess for predictors of screen failure. Average patient age was 48±14 years, average QRS duration was 134±37 ms, and 13 patients were pacemaker dependent. Using the standard left parasternal electrode position, 21 patients failed screening. Of these 21 patients with screen failure, 9 passed screening with the use of right parasternal electrode positioning, reducing screening failure rate from 21% to 12%. QT interval and inverted T wave anywhere in V2-V6 leads were found to be independent predictors of left parasternal screening failure (P=0.01 and P=0.04, respectively).

CONCLUSIONS

Utilization of both left and right parasternal screening should be used in evaluation of CHD patients for S-ICD eligibility. ECG repolarization characteristics were also identified as novel predictors of screening failure in this group. (Circ J 2016; 80: 1328-1335).

Cone Reconstruction of Atypical Ebstein Anomaly Associated with Right Ventricular Apical Hypoplasia

Cone reconstruction for tricuspid valve repair has revolutionized the surgical treatment of Ebstein anomaly. We present the case of a 58-year-old woman with atypical Ebstein anomaly and right ventricular apical hypoplasia who was spared from palliative shunt physiology by our use of cone reconstruction. Compared with other techniques, cone reconstruction of the tricuspid valve more closely replicates normal valvular anatomy and function. This surgical procedure can be applied to many anatomic variations of Ebstein anomaly, as in our patient's apparently unique instance of atypical Ebstein anomaly with right ventricular apical hypoplasia.

Survival and outcomes of patients with unoperated single ventricle

OBJECTIVE

Patients with unoperated single ventricle (SV) rarely survive into adulthood with good functional status and may develop Eisenmenger's syndrome (ES). We report outcomes of a 30-year cohort of such patients.

METHODS

Adult patients with unoperated SV were identified by searching the Mayo Clinic medical record from 1984 to 2014. Clinical data were collected and compared between patients with pulmonary stenosis (PS) and ES.

RESULTS

24 patients were identified (median peak-age 56 (31-77) years (11 ES, 13 PS); 22 had left ventricular morphology. 50-year transplant-free survival was 65% (95% CI 43 to 81). Median age at death was 55 years (31-77 years); 15 deaths (62%) occurred before oral pulmonary vasodilators were commercially available. Two-thirds of the cohort demonstrated preserved New York Heart Association functional class and median EF was 60% (49% to 62%). The majority of patients to survive into the fifth decade exhibited anatomy of double-inlet LV (DILV) with PS.

CONCLUSION

Selected patients with unoperated SV with PS and ES can survive with good functional class up to the eighth decade with good medical management. DILV/PS appears to be the ideal phenotype for advanced survival. Our outcomes may be considered when such patients with SV having 'balanced' physiology are evaluated for Fontan palliation. However, additional prospective study will be necessary to verify this assertion.

Cardiac Arrest in Pregnancy

This is the first scientific statement from the American Heart Association on maternal resuscitation. This document will provide readers with up-to-date and comprehensive information, guidelines, and recommendations for all aspects of maternal resuscitation. Maternal resuscitation is an acute event that involves many subspecialties and allied health providers; this document will be relevant to all healthcare providers who are involved in resuscitation and specifically maternal resuscitation.

Magnetic Resonance Elastography: A Novel Technique for the Detection of Hepatic Fibrosis and Hepatocellular Carcinoma After the Fontan Operation

OBJECTIVE

To evaluate the utility of magnetic resonance elastography (MRE) in screening patients for hepatic fibrosis, cirrhosis, and hepatocellular carcinoma after the Fontan operation.

PATIENTS AND METHODS

Hepatic MRE was performed in conjunction with cardiac magnetic resonance imaging in patients who had undergone a Fontan operation between 2010 and 2014. Liver stiffness was calculated using previously reported techniques. Comparisons to available clinical, laboratory, imaging, and histopathologic data were made.

RESULTS

Overall, 50 patients at a median age of 25 years (range, 21-33 years) who had undergone a Fontan operation were evaluated. The median interval between Fontan operation and MRE was 22 years (range, 16-26 years). The mean liver stiffness values were increased: 5.5 ± 1.4 kPa relative to normal participants. Liver stiffness directly correlated with liver biopsy-derived total fibrosis score, time since operation, mean Fontan pressure, γ-glutamyltransferase level, Model for End-Stage Liver Disease score, creatinine level, and pulmonary vascular resistance index. Liver stiffness was inversely correlated with cardiac index. All 3 participants with hepatic nodules exhibiting decreased contrast uptake on delayed postcontrast imaging and increased nodule stiffness had biopsy-proven hepatocellular carcinoma.

CONCLUSION

The association between hepatic stiffness and fibrosis scores, Model for End-Stage Liver Disease scores, and γ-glutamyltransferase level suggests that MRE may be useful in detecting (and possibly quantifying) hepatic cirrhosis in patients after the Fontan operation. The correlation between stiffness and post-Fontan time interval, mean Fontan pressure, pulmonary vascular resistance index, and reduced cardiac index suggests a role for long-term hepatic congestion in creating these hepatic abnormalities. Magnetic resonance elastography was useful in detecting abnormal nodules ultimately diagnosed as hepatocellular carcinoma. The relationship between stiffness with advanced fibrosis and hepatocellular carcinoma provides a strong argument for additional study and broader application of MRE in these patients.

Pregnancy and Delivery in Women With Congenital Heart Disease

Because of the growing population of patients with congenital heart disease (CHD), most maternal cardiac disease is now congenital in origin. For women with complex CHD, pregnancy poses an increased risk for both the mother, with complications of arrhythmias and heart failure being the most common, and the baby, with a higher chance of miscarriage, intrauterine growth retardation, and the need for early delivery. Pre-pregnancy counseling must be performed by cardiologists who have expertise in both CHD and pregnancy, with a detailed clinical assessment of the patient and the current hemodynamic situation, including echocardiography and an exercise test. In each case the approach must be individualized with consideration of the risks in each case. In some cases, such as Eisenmenger syndrome, pregnancy is contraindicated. Optimum outcomes in these complex patients are achieved when a multidisciplinary approach is used, involving maternal-fetal medicine specialists, cardiologists with expertise in CHD and obstetric anesthesia.