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Khokhar et al. Mini-invasive Surg 2022;6:2 https://dx.doi.org/10.20517/2574-1225.2021.97 Page 11 of 19

Prevention of AKI
Accurate identification of patients at high risk of developing AKI should prompt the use of appropriate
prevention strategies. Ratios of contrast volume to glomerular filtration rate of > 3.2 and threshold value of
contrast volume × serum creatinine to body weight of 2.7 were cutoffs identified by predicting mortality and
development of AKI [97,98] .

For these high-risk patients, adequate pre-hydration, particularly when combined with close monitoring of
volume status either conventionally or with the use of modern techniques such as RenalGuard system
(RenalGuard Solutions Inc, Milford, MA), is an important first step [99,100] .

For patients with baseline renal dysfunction, contrast sparing strategies including the use of alternative
imaging modalities, such as magnetic resonance imaging (MRI) or 3D transesophageal echocardiography,
for pre-procedural planning and intra-procedural guidance should be considered. Low-contrast volume CT
protocols which provide adequate assessment of aortic and peripheral vessels have been described [101-103] .
Pre-procedural TAVR CT can be performed with cardiac gating to evaluate coronary arteries, obviating the
need for invasive angiography and thereby further reducing the total contrast volume administered pre-
procedurally. Alternatively, echocardiography, gadolinium-free cardiac magnetic resonance tomography,
and fusion angiography can be used with procedural adaptions to perform an almost zero-contrast
procedure [104,105] . If small volumes of contrast are required, then the use of a non-ionic iso-osmolar contrast
media is recommended.

Meticulous attention should be given to vascular access to avoid vascular complications, especially major
bleeding. When necessary, a restrictive transfusion policy should be adopted. The use of embolic protection
devices may limit the burden of embolic damage to the kidneys, although future studies in this field are
awaited.

STROKE
Despite improvements in device technologies, operator experience, and a lowering in the risk profile of
patients, the rate of clinically relevant post-TAVR strokes remains static around 2% and seriously impacts
upon quality of life, morbidity, and mortality [106,107] . Additionally, silent cerebral ischemic lesions detected by
diffusion weighted MRI have been identified in up to 80% of patients undergoing TAVR [108-110] . Although the
mid- and long-term consequence of these silent infarctions is debated, some studies have suggested an
association with longer-term neurocognitive changes and dementia.

Acute cerebrovascular events: < 24 h
The majority of post-TAVR strokes occur within the first 24 h and are due to embolization of debris
composed of thrombus, calcification, atheromatous plaques, vascular endothelium, or tissue valve
fragments . Consequently, cerebral embolic protection devices (CEPD) were designed to capture and/or
[111]
deflect this debris and thereby reduce the incidence of peri-procedural stroke. Currently, only two devices
with Conformite Europeenne mark are commercially available, the Sentinel™ Cerebral Protection System
(Boston Scientific, Natick, MA) and TriGUARD™ (Keystone Heart Ltd, Herzliya, Israel) devices. The
Sentinel CPS is a 6 Fr system, which only covers the brachiocephalic and left common carotid arteries. In
contrast, the TriGUARD device is a larger 9 Fr system, which provides more complete coverage of all the
supra-aortic vessels. Globally, the use of CEPDs has gradually increased with data from the Society of
Thoracic Surgeons-Transcatheter Valvular Therapies registry revealing that a CEPD was used during 13% of
TAVR procedures by 2019 [112,113] . Both devices require the use of an alternative arterial access and may
potentially interfere with valve advancement and manipulation inside the aortic arch. Newer generation