Clinical features and outcomes of adult patients with single ventricle physiology not undergoing Fontan repair

Background

Adult patients with single ventricle (SV) physiology who had not undergone Fontan palliation are uncommon. Little is known about their clinical features and outcomes.

Objective

This study aims to describe the clinical features, cardiovascular outcomes and long-term survival of patients with SV physiology without Fontan palliation.

Methods

Data were collected retrospectively from SV physiology patients followed in adult congenital heart disease (ACHD) units of five tertiary referral centers. None of them had Fontan palliation. Baseline data were recorded on the first visit at ACHD unit. Death was considered as main endpoint. Other outcomes such as atrial or ventricular arrhythmias, endocarditis, ICD or pacemaker implantation, admission for heart failure and heart transplant were also collected and analyzed. Association between clinical/analytical baseline variables and death was also evaluated by univariate Cox regression.

Results

128 patients were included. On the first visit, mean age was 32.3±10.9 years, being the most common defect double inlet left ventricle (63p, 49.2%). The single ventricle had left morphology in 106 cases (82.8%). At baseline mean heaemglobin was 19.1±2.8 g/dl, mean O2 Sat 83±6.9% and 46 patients (36%) had a NYHA status III or IV. 4 different groups were found: a) Unrestricted pulmonary flow with Eisenmenger physiology (24p, 18.8%); b) Restricted forward pulmonary flow with or without pulmonary banding (46p, 35.9%); c) Aortopulmonary shunts as a source of pulmonary flow (20p, 15.5%) and d) cavopulmonary shunt (Glenn) as a definitive palliation (38p, 29.7%). After 7.3±4.1 years follow-up, mortality was 22.7% (29 patients), being sudden death (9p, 7%) the most frequent cause. Survival rate at 5 and 10 years of follow-up were 85% and 76% respectively (Figure 1). About of the rest of the outcomes, highlighting a high rate of atrial tachycardia (38.3%), admission for heart failure (23.4%), stroke (17.2%), endocarditis (9.4%), pacemaker/ICD implantation (11.8%). Baseline variables associated with higher mortality were: older age (HR=1.1 [1.004–1–087]); NYHA III or IV (HR=5.5 [2.4–12.4]); thrombocytopenia (HR=1.01 [1.001–1.003]); anticoagulant treatment (HR=2.6 [1.7–3.9]); glomerular filtration rate below 60 ml/min (HR=3.77 [1.5–9.6]); QRS width (HR=1.03 [1.01–1.05]); atrial arrhythmias (HR=3.1 [1.5–6.5]); moderate or severe AV valve regurgitation (HR=1.5 [1.15–1.97]) and ventricular ejection fraction (HR=0.94 [0.91-0.97]).

Conclusions

Adults survivors with SV physiology without Fontan palliation have a high mortality and frequently suffer from serious cardiovascular events. Several clinical (NYHA status, previous atrial arrhythmias, anticoagulant treatment), analytical (renal function, thrombocytopenia), ECG (QRS width) and echocardiography (AV valve regurgitation and EF) factors can identify patients at higher risk of death.

Figure 1. Survival curve

Funding Acknowledgement

Type of funding source: None

Long term outcome of single ventricle physiology with pulmonary restriction not undergoing Fontan repair

Background

Patients with univentricular physiology who do not complete the palliation to Fontan are a heterogeneous group with unknown long term outcome.

Aims

This study aimed at describing the clinical course and long-term survival of patients with SV physiology with restricted pulmonary flow that had not undergone a Fontan type of repair.

Methods

From the prospectively maintained databases of the adult congenital cardiac units of five tertiary referral centers, data from all SV physiology patients were obtained. Patients completing a Fontan type palliation or developing Eisenmenger physiology and segmental pulmonary hypertension were excluded. Baseline data were recorded on the first visit at adult congenital heart disease (ACHD) unit. The primary end point was death.

Results

101 patients (50.5% females) were identified. Mean age at end of follow up was 39.3±11.3 years. Of these, 45 (44.6%) were unoperated (group 1, restricted forward pulmonary flow with or without pulmonary banding), 38 (37.6%) had undergone a cavopulmonary shunt as a definitive palliation (group 2) and 18 (17.8%) had aortopulmonary shunts (group 3). The main diagnosis was double inlet left ventricle (DILV) (N: 52, 51.5%) and most of the ventricle was left (82.2%). The principal reason for not performing a Fontan repair was mean pulmonary artery pressure >18 mmHg. At initial visit at the ACHD unit patients were 32.2±11.1 years of age. 35% of the patients were in NYHA class III-IV, with no differences between groups. However, patients in group 2 had worse oxygen saturation (p=002) and higher haemoglobin (p=0.037). After a mean follow-up of 7.3±4.1 years, mortality was 20.8% (21 patients), being sudden death (7p, 6.9%) the most frequent cause. Patients in group 3 showed worse ventricular function (p=0.0001) and a trend to higher mortality that did not reach statistical significance (HR 2.7, CI 95% 0.91–8.14, P=0.07).

Conclusions

Patients with single ventricle physiology not undergoing Fontan repair are a population of high risk, with sudden death as main driver of mortality. Patients palliated with aortopulmonary shunts are prone to worse ventricular function and a trend to higher mortality.

Funding Acknowledgement

Type of funding source: Public hospital(s)

P1721 Reversible heart right failure. Pulmonary hypertension induced by Tyrosine Kinase Inhibitors

BACKGROUND

Pharmacologically induced pulmonary hypertension (PH) is infrequent nowadays and it is included in the type 1 of the classification of PH.

Tyrosine kinase inhibitors (TKI) are the cornerstone of the treatment of many haemotopoietic stem cell diseases. Dasatinib is a second-generation TKI used in chronic myeloid leukemia (CML) and as an infrequent cardiovascular side-effect (< 0,50%) could induce PH, usually reversible but life threatening. Only a few case series are published.

CASE DESCRIPTION: We present a 51-year-old woman who was diagnosed of a CML when she was 46. Initially, she underwent therapy with imatinib but after 5 years of treatment she developed resistance to this drug, and dasatinib was prescribed as a second line drug. After 3 months of continuous treatment, she started with dry cough and effort dyspnea. Blood analysis, EKG and Chest X-Ray were made but did not show outstanding findings. An unspecific viral infection was the final diagnosis. The patient clinical condition deteriorated with major dyspnea and edemas in the lower limbs. A TTE showed moderate tricuspid regurgitation and severe HP systolic pulmonary artery pressure (sPAP) of 80 mmHg. The pulmonary acceleration time was shortened and a mesosistolic knock was present. Systolic dysfunction of the right ventricle and pericardial effusion (image 1,2,3,4) were noted. The right atrium was not dilated. Cava vein was dilated but with inspiratory collapse >50%. The left ventricular function was preserved, but first degree diastolic dysfunction was found. Other causes of PH were excluded (types 2, 3, 4). A CT pulmonary angiogram did not show segmental perfusion defects. Finally, a right heart catheterization confirmed the TTE findings: severe precapillary PH without postcapillary component. After the diagnosis was confirmed, TKI was stopped and double targeted therapy with ambrisentan + tadalafil was started. After 6 months of treatment a new TTE was made with complete reversal of the secondary changes in the myocardium induced by the PH. No tricuspid regurgitation was detected nor any indirect sign of PH was found. (image 5,6).

CONCLUSIONS

Drug-induced PH is rare nowadays and most cases were described in the seventies in the USA related with the epidemic of anorexigenic drugs. Although the pathogenesis still remains unclear, treatment includes immediately stopping the offending agent.

Echocardiography due to its accessibility, reproducibility, consistence and low cost should be the first diagnostic tool to be considered, because as it is known, in the early stages of the disease, before developing right disfunction, clinical and conventional tests are non-specific.

Abstract P1721 Figure. Echo images: previous and afte treatment

Human and rabbit inter-species comparison of ionic mechanisms of arrhythmic risk: A simulation study

Experimental studies of pro-arrhythmic mechanisms are scarcely performed in humans due to the limited availability of human cardiomyocytes. Subsequently, extrapolation of animal experimental research to humans is widely extended. Our aim is to systematically compare the ionic mechanisms of the main cellular biomarkers of arrhythmic risk between human and rabbit using computer simulations. For this purpose four stimulation protocols were applied to the Mahajan et al. rabbit ventricular action potential (AP) model for control conditions and for ± 15 and ± 30% variations in the ionic current conductances of the main repolarization currents to quantify cellular biomarkers. Sensitivity of every simulated biomarker to every parameter modification was compared to that obtained for human in our previous work. Our results show that the ionic mechanisms involved in AP triangulation, systolic intracellular calcium concentration and AP duration (APD) accommodation to abrupt changes of pacing rate are very similar in both species. Unfortunately, significant differences were found in the ionic mechanisms related to APD, restitution properties and rate dependence of intracellular calcium and sodium concentrations. In conclusion, extrapolation of experimental research in rabbit to humans is limited by the existence of species dependent ionic mechanisms. In addition, this analysis is very useful for understanding and improvement of mathematical models.