Summary
Progress in the medical treatment of patients with heart failure with systolic dysfunction, cardiac resynchronization therapy, internal cardiac defibrillators and multidisciplinary management programmes has resulted in dramatic improvements in survival and quality of life; however, this progress has led to an increase in the prevalence of advanced heart failure. In the context of organ shortage for cardiac transplantation, the technological developments in left ventricular assist devices, shown in recent positive clinical studies, provide real hope for patients with advanced heart failure. This article summarizes the most recent clinical studies concerning left ventricular assist devices and discusses for whom and when a left ventricular assist device should be proposed.
Résumé
Les progrès du traitement médicamenteux, la resynchronisation cardiaque, l’utilisation des défibrillateurs implantables, l’éducation du patient et l’organisation du suivi ont permis d’améliorer la qualité de vie et la survie des patients insuffisants cardiaques avec dysfonction systolique, mais ces progrès se sont aussi traduits par une augmentation de la prévalence des patients en insuffisance cardiaque avancée. Dans le contexte de pénurie d’organes pour la greffe cardiaque, les progrès technologiques des assistances monoventriculaires gauches apportent des résultats cliniques très encourageants et constituent un réel espoir pour la prise en charge des patients insuffisants cardiaques sévères. Cet article fait le point sur les données les plus récentes concernant l’assistance monoventriculaire gauche et discute quand et pour quels patients l’envisager.
Background
Progress over the past 20 years in the medical management of patients with HF with systolic dysfunction has been accompanied by a significant improvement in survival and quality of life due to the prescription of ACE inhibitors, ARBs, beta-blockers and anti-aldosterones, CRT and ICDs, in addition to multidisciplinary management programmes based on education of the patient and coordination of care . These strategies have also resulted in changes in the clinical profile as well as an increase in the number of patients with advanced HF.
The prevalence of HF in Europe is estimated to be between 2 and 3% of the general population, with 15 million patients having symptomatic HF. Patients with advanced HF represent approximately 0.4% of the population, i.e. 60,000 patients. If we estimate that around 50% of these patients have altered systolic function and that 30−50% are < 75 years of age, then 10–15,000 patients should require a heart transplant, a total artificial heart, a biventricular assist device or a LVAD.
Cardiologists should learn to recognize these patients because there has been remarkable progress in cardiac assist devices over the past few years, while access to transplantation remains very limited. An LVAD can be used as a bridge to heart transplantation, until possible recovery, or can be used long term or even permanently (destination therapy). During the past 10 years, 1-year survival rates for destination therapy have increased from 52% with pulsatile devices to 68% with continuous flow devices and to 94% in bridge-to-transplant indications . Moreover, the incidence of complications has dramatically decreased with the use of continuous flow devices. Their reliability, longevity (> 5 years) and battery autonomy (up to 10 h) are continuously improving and consequently have contributed to an improvement in quality of life .
The aims of this article are to describe the profiles and management of patients with advanced HF for whom an LVAD should be proposed and to consider when an LVAD should be proposed, on the basis of the most recent clinical studies.
When should a heart failure (HF) patient be referred to an HF centre?
The majority of HF patients with left ventricular systolic dysfunction are followed in an ambulatory setting and should receive optimal therapy based on the use of recommended medications, CRT/ICD devices when indicated and an organized care plan as defined by the international guidelines . It is crucial to take time to titrate the medications up to the maximal tolerated doses and to optimize CRT stimulation during the initial phase and follow-up. At the advanced stages of HF, particular attention should be paid to deciding if the time for heart transplantation or LVAD implantation has occurred. The decision to recommend cardiac replacement or LVAD implantation remains difficult and concerns a small proportion of patients, a large majority of whom are currently referred too late. The paradox is that these patients, for whom the prognosis is worse than most cancers, are referred late, while the level of intervention and quality of management should at least equal what is given to cancer patients. Hence, patients with severe HF should be directed earlier to experienced HF teams in order to discuss therapy, evaluate prognosis and organize a care plan, allowing elective implantation of an LVAD if necessary and pre-empting the evolution of clinical situations. Several clinical and biological variables should alert the primary care physicians to refer the patient to the HF team. Pertinent indicators of severity can be: very symptomatic (e.g. unable to climb a flight of stairs without dyspnoea); intolerant to ACE inhibitors, ARBs or beta-blockers; natraemia < 135 mmol/L; hospitalized repeatedly during the past 6 months; and persistent elevation of natriuretic peptides. Beyond these simple indicators, HF risk scores should be used more often. The HF Survival Score and the Seattle HF Score seem to be relevant in these patients, even if they can underevaluate prognosis in the most severe patients; their routine use is not frequent in Europe but the severity of the patients should justify broader utilization of these scores to facilitate the best treatment strategies. Earlier referral has to be preferred to improve patient selection for LVAD implantation or heart transplantation.
The HF team will ensure that all conventional medical strategies have been optimally implemented and will accurately evaluate right heart function as well as other factors that can influence the therapeutic decision (see below). Based on this evaluation, a strategy of management and outpatient follow-up will be proposed in collaboration with the cardiologist and general practitioner. This period of time provides a good opportunity to implement patient education and give information about LVADs and heart transplantation. Heart transplantation currently offers the best quality of life, autonomy and chance of socioprofessional reintegration and the longest survival. However, the shortage of organ donors dramatically limits the probability of transplantation in ambulatory waiting patients and emergency transplantation is given priority in industrialized countries. In this context, during consultations where heart transplantation is discussed, the possible requirement for a period of bridge assistance until transplantation should be systematically mentioned.
For which patients should a left ventricular assist device be proposed?
Patients with chronic heart failure
As recommended by the European Society of Cardiology, an LVAD may be considered as a destination therapy to reduce mortality in patients in New York Heart Association class 3B to 4, who remain symptomatic despite optimization of the recommended HF medications ( Fig. 1 ) . As described by the European working group on advanced heart failure these patients complain of major limitations in their daily life, with dyspnoea and fatigue present at rest or during minimum effort, which confines them to bed or at home. For ambulatory patients, excursions outside are feared and rare, and walking is limited. These patients have repeated episodes of salt and water retention or low cardiac output episodes and are often rehospitalized, with more than one hospitalization during the previous 6 months. All these signs appear despite optimization of (or attempts to optimize) their medications . These patients do not respond to cardiac resynchronization therapy or respond only transiently and inverse left ventricular remodeling is not observed. Above all, drug titration is often impossible and at the most advanced stages, drug treatments (ACE inhibitors, ARBs, beta-blockers, antialdosterones) have to be decreased due to hypotension, renal insufficiency and profound weakness. At this stage of advanced HF, the main objective becomes optimization of volaemia and high doses and combinations of diuretics have to be used. The classification of the INTERMACS registry proposes seven clinical scenarios that allow better definition of the functional limitations and degree of severity of patients with advanced HF ( Table 1 ) . Although this classification does not take into account the arrhythmic risk, it is extremely useful in daily clinical practice for the management of patients and for making decisions regarding therapeutic strategies. Community cardiologists should know this classification since it also has a prognostic value . These patients have a profound alteration of left ventricular ejection fraction (< 25%). The alteration of systolic function should not be underestimated, and higher values may be found in cases of significant mitral insufficiency. Echocardiography shows marked anomalies in the mitral profile and an increase in filling pressure concordant with the level of natriuretic peptides, which remain increased between congestive episodes . An increase in central venous pressure despite haemodynamic optimization indicates an alteration of RV function. It is crucial to perform a comprehensive evaluation of RV function and to identify RV dysfunction because this is a determining prognostic factor. During follow-up of ambulatory HF patients, an increase in pulmonary pressure and/or pulmonary resistance should direct the patient to a HF reference centre because this indicates advanced disease and an increased risk of RV dysfunction. RV dysfunction is one of the main determinants of operative risk and may preclude the possibility of LVAD implantation. The patient’s age is not a formal contraindication and depending on the general state of the patient and the presence of comorbidities, implantation of mechanical assistance may be proposed in patients > 65 years of age .
| Classification | Description | Time frame for definitive intervention |
|---|---|---|
| 1 | Patient with life-threatening hypotension despite rapidly escalating inotropic support, critical organ hypoperfusion with increasing lactate levels and/or systemic acidosis. “Crash and burn” | Needed within hours |
| 2 | Patient with declining function despite intravenous inotropic support, may be manifested by worsening renal function, nutritional depletion, inability to restore volume balance. “Sliding on inotropes” | Needed within a few days |
| 3 | Patient with stable blood pressure, organ function, nutrition and symptoms on continuous intravenous inotropic support, but demonstrating repeated failure to wean owing to recurrent symptomatic hypotension or renal dysfunction. “Dependent stability” | Elective over a few weeks |
| 4 | Patient can be stabilized close to normal volume status but experiences frequent relapses into fluid retention, generally with high diuretic doses. Symptoms are recurrent rather than refractory. More intensive management strategies should be considered, which in some cases reveal poor compliance. “Frequent flyer” | Elective over weeks to months as long as treatment of episodes restores stable baseline, including nutrition |
| 5 | Patient is living predominantly within the house, performing activities of daily living and walking from room to room with some difficulty. Patient is comfortable at rest without congestive symptoms but may have underlying refractory elevated volume status, often with renal dysfunction. “Housebound” | Variable, depends upon nutrition, organ function, and activity |
| 6 | Patient without evidence of fluid overload is comfortable at rest and with activities of daily living and minor activities outside the home, but fatigues after the first minutes of any meaningful activity. “Walking wounded” | Variable, depends upon nutrition, organ function, and activity |
| 7 | A placeholder for future specification, patients without recent unstable fluid balance, living comfortably with meaningful activity limited to mild exertion | Transplantation or circulatory support not currently indicated |
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