Burden of aortic stenosis (AS) is rapidly increasing along with epidemiologic transitions of the global population and transcatheter aortic valve replacement (TAVR) has quickly spread. TAVR is also employed in treating patients with Aortic stenosis (AS) at intermediate operative risk. Even though it is less invasive interventional strategy, it still carries some issues concerning post-procedural optimal antithrombotic strategy.
Ischaemic/embolic and bleeding complications are strongly related to mortality, thus the optimal antithrombotic approach after TAVR still remains debated. This makes the management of elderlies undergoing TAVR is particularly complex.
Geriatric patients suffer from high bleeding and thromboembolic risks, whose balance is particularly subtle due to the presence of concomitant conditions, such as atrial fibrillation and chronic kidney disease, that make the post-TAVR antithrombotic management particularly insidious. Due to which making the correct choice of antithrombotic strategy after TAVR particularly challenging. This scenario is further complicated by the lack of specific evidence regarding the ‘real-life’ complex conditions typical of the geriatric syndromes, thus, the management of such a heterogeneous population, ranging from healthy ageing to frailty, is far from being defined.
Cerebrovascular complications in TAVR
The Placement of Aortic Transcatheter Valves (PARTNER) trial has demonstrated that TAVR improved 1-year survival compared to medical therapy, but it was associated with higher rates of stroke at 30 days. High thromboembolic risk, anticoagulation is required during TAVR. Even if practice patterns widely vary and the current indications are mainly based on expert consensus rather than on evidence from randomized clinical trials, unfractionated heparin regimen is preferred to direct thrombin inhibitors. Interestingly, besides clinically apparent strokes, neuroimaging studies have shown that more than two-thirds of patients experience post-TAVR multiple silent ischaemic-embolic lesions, spread across both hemispheres.
Antithrombotic therapy in patients with atrial fibrillation
Atrial Fibrillation is one of the most relevant comorbidities in patients undergoing TAVR. Post-procedural stroke may be also associated with comorbidities, with pre-existing rhythm disturbance and NOAF being the most relevant. NOAF has been related to ischaemic events in the first 30 days (subacute stroke) and pre-existing AF up to 1 year (late stroke) after the procedure.
The comparison between direct oral anticoagulants (DOACs) and vitamin K antagonists (VKAs) has been tested in AF patients undergoing TAVR, demonstrating the non-inferiority of DOACs in terms of all-cause mortality, major and/or life-threatening bleeding and stroke.
The rivaroxaban-based strategy resulted more effective than an antiplatelet-based one in the prevention of subclinical leaflet-motion abnormalities. Antiplatelet Therapy for Patients Undergoing Transcatheter Aortic Valve Implantation (POPular-TAVI) trial, which included patients with an established indication for long-term oral anticoagulation, confirmed a higher incidence of bleeding events among subjects receiving oral anticoagulation plus clopidogrel than those treated with OAC alone.
Antithrombotic therapy in patients with chronic kidney disease
One of the most frequent comorbidities observed in elderly patients undergoing TAVR is represented by chronic kidney disease (CKD), which seems to be inherently related to a more rapid AS progression. Coagulation abnormalities represent relevant causes of morbidity and mortality in CKD, since the coagulation system is altered due to uraemic metabolism-dependent abnormalities in platelet and vessel function leading to increased risk of both bleeding and thrombosis.
An optimal antithrombotic strategy in elderly CKD patients undergoing TAVR, it may be wise to consider a transitory DAPT in patients with low bleeding risk and an immediate SAPT strategy when the risk is high.
TAVR in patients with autonomic dysfunction
The most common symptom of autonomic dysfunction is orthostatic hypotension, occasionally causing syncope. AS also presents with exertional dyspnoea and syncope. severe autonomic failure seems to be a strong predictor of mortality in both symptomatic patients with AS undergoing invasive treatment and asymptomatic patients treated conservatively.
Orthostatic hypotension is associated with an increase in markers of coagulability, although the mechanisms have to be elucidated. In elderly patients with Parkinson’s disease, the thromboembolic risk seems to be increased by a combination of factors, which include immobility in more advanced stages, chronic inflammation and increased levels of homocysteine due to treatment with L-DOPA.
Antithrombotic therapy and geriatric syndromes
Physical performance impairments, very frequent in the elderly subjects, are often linked to increased risk of falls, one of the most dramatic events in this population, frequently resulting in negative outcome. A lot of evidence has demonstrated the impact of frequently prescribed drugs, such as antidepressants, antihypertensive (especially diuretics), and digitalis, at increasing fall risk in people aged over 65.
Mood disorders are also very frequent among elderlies, with relevant implications in terms of medical complications. In older patients undergoing surgery for AS, anxiety has been strongly associated with increased morbidity and mortality risks. Blood disorders including anaemia, thrombocytopenia and acquired coagulative disorders are frequent among older TAVR recipients. Extensive evidence has detected an association between pre-existing anaemia, particularly common among people over 65 years, and long-term mortality in elderly TAVR patients.
Elderly patients, who constitute the vast majority of people undergoing TAVR, represent a heterogeneous population, with highly variable characteristics and great vulnerability, suffering from several comorbidities and various degrees of disabilities.
A thorough assessment of possible ischaemic and bleeding complications and an attempt at attenuating these risks, also through behavioural measures, still remain the main challenges the physician has to face, awaiting for further evidence aiming to provide suitable indications for the complex real-life clinical practice.