Buendía-Fuentes F, Gordon-Ramírez B, Dos Subirà L, Merás P, Gallego P, González A, Prieto-Arévalo R, Segura T, Rodríguez-Puras MJ, Montserrat S, Sarnago-Cebada F, Alonso-García A, Oliver JM, Rueda-Soriano J. Can J Cardiol. 2022 Jul;38(7):1111-1120. doi: 10.1016/j.cjca.2021.06.001. Epub 2021 Jun 9. PMID: 34118376.
Commentary by Dr. Simon MacDonald (London, UK), section editor of ACHD Journal Watch
Take Home Points
Univentricular heart patients, not having undergone a Fontan palliation, have a high mortality rate and frequent major cardiovascular events in this largest study to date of these unique physiology patients, a retrospective multicentre study from Spain. Moderate atrioventricular regurgitation, thrombocytopaenia with platelet count < 150 x103/mm3, renal dysfunction with GFR<60mls/min/1.73m2, QRS>120ms at baseline visit, suggested a cohort at higher risk of mortality.
Commentary from Dr Simon MacDonald (London, UK): Single ventricle physiology patients compromise a group in which generally one ventricle is hypoplastic and biventricular repair is not possible. These patients tend to undergo a Fontan palliation whereby systemic venous return is directed into the pulmonary arteries and the ventricular mass is committed to the systemic arterial circulation. Those who do not undergo this may survive due to intracardiac shunting and live into adulthood. There is little known on this patient group about what factors can determine survival.
The authors looked at long-term outcomes in this group, a retrospective review of patient data from seven ACHD centres in Spain. They grouped patients into Eisenmenger, those with restricted pulmonary blood flow and those with an aortopulmonary shunt.
A total of 146 patients were identified, mean age 32.5±11.1 years with mean follow-up of 7.3±4.1years. 54.1% were female. Restricted pulmonary blood flow was the commonest group (86 or 58.9% with 14 patients with PA banding and 41 without, 31 had a Glenn shunt (SVC-PA anastomosis)) followed by aortopulmonary shunt (34 or 23.3%) and Eisenmenger (26 patients or 17.8%). Reasons for not undergoing Fontan palliation was high risk candidate or patient refusal 48% and high mean PA pressure (>18mmHg) 26.7%, and hypoplastic pulmonary arteries and complex pulmonary venous return. Patients had double inlet left ventricle (71 or 48.6%), tricuspid atresia (28 or 19.2%), unbalanced AVSD (16 or 11%), mitral atresia/hypoplastic left heart (9 or 6.2%), double outlet right ventricle (7 or 4.8%) with 108 or 74% having a predominant left ventricle.
Interestingly, 52.1% of patients had been transferred from pediatric care with almost 50% previously lost to specialist follow-up from their index review from ACHD services. 10 patients were over 50 years at baseline.
Thirty-three patients (22.6% died) over follow-up of 7.3±years, with main causes sudden cardiac death (36.4%), advanced heart failure (27.3%) with mean age at death 39.4±12.2 years. Overall survival was 86% at 5 years, 74% at 10 years. Survival between the 3 groups was as shown in figure 3 below:
On multivariable analysis, at least moderate atrioventricular valve regurgitation, platelet count <150x 103/mm3, GFR <60mls/min/1.73m2, and QRS>120ms were significant predictors of mortality. Right ventricular morphology was not associated with higher mortality.
In terms of secondary outcomes, freedom from heart failure admission, atrial arrhythmias, and stroke were as shown in the graphs in fig 4:
This study is the largest reported experience with this physiology. Limiting factors were that it was retrospective, being hampered with regards to data collection and lack of enough information to identify potentially important markers (e.g. VO2 max, biomarkers, imaging findings), and there may have been referral and immortality bias with only survivors into adulthood being reported and those that the ACHD services became aware of being studied. This is a difficult group of patients to study with each centre having low numbers individually. However, it adds to the literature that these patients can survive into adulthood but with high mortality and frequent cardiovascular events with potential risk factors for a high-risk cohort identified.
