7.2 Evidence review
Malignancies are often the reason to choose a bridge-to-candidacy strategy [93].
Frailty is a biological syndrome of impaired physiological and homeostatic reserve and heightened vulnerability to stressors, resulting from multiple morbidities, ageing and disability [94], occurring in nearly 10% of the patients in the INTERMACS Registry [95]. Frailty contains at least one of the following phenotype symptoms: shrinking, weakness, exhaustion, slowness and inactivity. No specific definition has been validated, with the exception of the Fried scale [94, 96]. Frailty leads to significantly longer duration of mechanical ventilation, length of stay and long-term mortality in patients with LT-MCS [47, 48, 95]. After LT-MCS implantation, regression of frailty may occur [97]. Advanced age is a risk factor for frailty and comorbidities. However, several retrospective studies revealed acceptable outcomes after LT-MCS implantation in the elderly. Therefore, age alone should not be used as an exclusion criterion for LT-MCS implantation [98, 99].
Cardiac cachexia (CC) is the unintentional non-oedematous weight loss of >5% over at least 6 months. CC is associated with older age and can result in longer length of hospital stay and higher costs. CC (19%) is among the most common comorbidities of HF together with malignancies (34%) and chronic obstructive pulmonary disease (29%). Pathophysiological mechanisms of CC include metabolic and neurohormonal abnormalities [100]. However, the preoperative health status Kansas City Cardiomyopathy Questionnaire has limited association with outcomes after ventricular assist device (VAD) implantation [101]. For assessment of nutritional status, the prognostic nutritional index [serum (pre-) albumin and total lymphocyte count] might be used as an indicator of a worse outcome [102].
Renal dysfunction (RD) in advanced HF should be evaluated and categorized as primary or secondary dysfunction. LT-MCS implantation may reverse secondary RD [37, 56, 71, 103]. Severe RD (glomerular filtration rate <30 ml/min) increases the risk of the perioperative requirement for renal replacement therapy, early RV failure, infections and hospital mortality in patients with an LVAD [37, 56, 71, 103]. Primary RD should be ruled out. Primary non-reversible renal disease with severe RD may contraindicate LT-MCS implantation due to poor prognosis [37, 56, 71, 103]. Chronic haemodialysis should be considered as a relative contraindication for LT-MCS placement in highly selected patients. There are limited data on the safety of peritoneal dialysis while on LT-MCS support.
Preimplant major stroke is present in 3.6% of the patients in the INTERMACS Registry; other cerebrovascular diseases are present in 3.8%. Neurological and cognitive function should be assessed before LT-MCS implantation [104]. No worldwide accepted psychosocial assessment is available. The Stanford Integrated Psychosocial Assessment for Transplant can, however, certainly be used for LT-MCS candidates [105, 106].
Pre-LT-MCS evaluation of pulmonary function is mandatory [107]. There is a high prevalence of chronic obstructive pulmonary disease among patients with HF that can lead to a worse prognosis. Restrictive abnormalities and/or altered alveolocapillary transfer may be a consequence of chronic pulmonary venous congestion. Re-evaluation after correction of fluid overload is recommended. To assess pulmonary hypertension, invasive haemodynamic assessment of pulmonary vascular resistance (PVR) is mandatory. Normalization of high PVR following LT-MCS support, thereby enabling a successful heart transplant (HTx), has been shown previously [108, 109].
Polysomnography is recommended in case of suspected sleep apnoea, drowsiness, periodic breathing and desaturation episodes, although the role of non-invasive ventilation in central sleep apnoea syndrome has been questioned.
Non-thyroidal illness syndrome has low levels of plasma T3 and T4, increased levels of reverse-T3 and normal or slightly decreased levels of thyroid-stimulating hormone. Non-thyroidal illness syndrome is frequent in critically ill patients (prevalence of 18%) and has a negative prognostic role. The early postoperative finding of low T3 syndrome is associated with a higher mortality rate and complications [110, 111].
Diabetes is common in recipients of LT-MCS (43%) but, in contrast to results from a previous study [28], does not increase mortality or serious adverse event rates during LT-MCS support [112, 113]. In a retrospective analysis (n = 244), LT-MCS therapy was associated with improvement in diabetic control that was attributed to improvements in cardiac output and normalization of biochemical derangements [114]. More awareness of diabetic patients with advanced HF is necessary [115].
Faecal occult blood testing during evaluation of potential candidate for LT-MCS is recommended. In the CF-VAD population, gastrointestinal (GI) bleeding is common and is associated with the occurrence of angiodysplasia [116] and acquired von Willebrand syndrome [117].
Hepatic dysfunction may occur as hypoxic hepatitis [118] in patients with acute HF or more commonly as ‘cardiohepatic syndrome’ in the setting of congestive HF [119–121]. Liver dysfunction is a predictor of poor outcome in patients with advanced HF requiring LT-MCS [41]. However, the liver has outstanding regeneration potential, which may occur after LT-MCS implantation [59, 63, 122–126]. Preoperative liver dysfunction influences the levels of circulating coagulation proteins and affects postoperative blood product requirements [127].
Short- or long-term MCS may rescue patients with peripartum cardiomyopathy [128]. Successful delivery in a patient with LT-MCS has been described [129].