Heart failure management in congenital heart diseases: many familiar faces and some strangers

This editorial refers to ‘Advanced heart failure in ACHD: the role of renal dysfunction in management and outcomes’, by K. Krishnathasan et al., https://doi.org/10.1093/eurjpc/zwad094. Heart failure (HF) is a common final pathway affecting the history of many congenital heart diseases (CHD), irrespective of the specific anatomic diagnosis. The prevalence of patients with CHD and HF is expected to grow exponentially, becoming a tremendous challenge for the upcoming years. The pathophysiologic vision of HF has progressively moved from a single-organ disease to a multisystemic syndrome. In this view, the concept supporting the current therapy is the inhibition of neurohumoral activation that, in turn, triggers and perpetuates adverse myocardial remodelling and initiates a vicious circle leading to worsening congestion. Within this pathophysiologic framework, the kidney plays a two-fold role as a target and effector. Based on this background, in the last two decades, many seminal evidences have substantially contributed to the progressive reframing of HF management in patients with acquired heart diseases.1 Although hyperactivation of the renin–angiotensin–aldosterone system (RAAS) has been proved also in patients with HF and CHD,2 evidences that its pharmacological manipulation affects outcomes are still very limited. The paper by Krishnathasan et al.3 besides exploring the impact of renal failure on outcomes of CHD depicts an interesting picture of contemporary HF management in a large referral centre. There are several very intriguing key points that open an extremely stimulating discussion. First, in this cohort, a significant proportion of CHD patients are treated at admission with conventional anti-HF medications based on a plausible pathophysiologic rationale. In particular, the percentages of RAAS antagonist and beta-blocker use roughly reproduce those reported in European registries enrolling patients with acquired heart diseases.4 The second key point is that fluid overload was a major clinical presentation of CHD patients with HF needing uptitration of diuretic doses and switch to intravenous administration. Unsurprisingly, there was a significant association between renal function and both the degree of congestion and the required dose of diuretics. These findings also reproduce the clinical practice reported in the general population of patients presenting with acute or worsening HF, suggesting that congestion is a frequent clinical phenotype, irrespective of the underlying aetiology of HF and cardiac anatomy. The third point, highlighting strong connections between this clinical subset and the whole cohort of HF patients, is the independent prognostic role of renal function on survival and achievement of a durable post-discharge euvolaemia.5 Despite these similarities, data provided by Krishnathasan et al. also suggest epidemiological and pathophysiological peculiarities that need to be taken into account. In the first place, the most frequent underlying diagnosis was tetralogy of Fallot; therefore, different from patients with acquired diseases, right HF was the dominant clinical presentation in this subset of patients. We might presume that venous congestion, by reducing transglomerular filtration pressure, may represent a specific additional hit for the kidneys in this clinical setting. Furthermore, the Fontan circulation can be viewed in some ways as a model of HF, characterized by the association of congestion and low forward output. Finally, among the spectrum of CHD, severe erythrocytosis, in patients with Eisenmenger physiology, and preload curtailment, in patients who had undergone atrial switch, represent an additional layer of complexity in the interaction between the heart and kidneys (Figure 1). All these issues might be regarded as the pathophysiologic interpretation of the clear-cut separation of the survival curves of patients with vs. those without renal function impairment, nicely shown by this paper. Diagram summarizing interaction between specific pathophysiological conditions, typical of congenital patients with heart failure, and kidneys.