A Case for Transthoracic echocardiography
The use of TOE had been paramount in the early stages of TAVI use with
aiding to observe catheter positions, valve sizing, evaluation of stent
position and ruling out any complications from the procedure. The most
important use for TOE is to rule out PVL. The occurrence of PVL is
reducing at TAVI experience increases and technology has improved. With
the shift from GA to sedation techniques, TOE cannot be used in these
group of patients and so TTE may provide sufficient information to the
operator without having the risks of a GA or TOE intubation of the
oesophagus. Jain et al observed the outcomes and findings of those who
has TTE during TAVI. 278 patients were included in the study and
received sedation. Mean age was 82.1+/-7.3 years, with 52.5% of female
patients. There were no intraprocedural deaths. 1.4% suffered from CVA
and 1.8% died during TAVI hospitalisation. TTE images were reviewed by
a sonographer and cardiologist and images were rated in terms of
quality. Procedural echo was excellent in 2.5%, good in 48.9% and poor
in 10.4%. Pre procedure echo images were excellent in 5.4% and poor in
8.3%. There was no difference in the rate of poor image quality for pre
procedural TTE vs procedural TTE, and poor pre-procedure TTE did not
predict poor procedural image quality. 24-hour echo was performed by the
same sonographer and was noted to have excellent image quality in 6.5%,
good in 59.7% and poor in 4%. Parasternal TTE images were optimal in
79.5% of cases, apical images were optimal in 61.5% of cases and stent
depth was visualised optimally in 93.5% of cases. Patients with a body
surface area >2m2 were more likely to have a poor rated
image as well as suboptimal apical and parasternal views. TTE and
invasive haemodynamics were used to identify the need for post
deployment stent ballooning due to PVL in 8.3%. Left ventricular
outflow tract and midventricular obstruction were correctly identified
in 7 cases and treated. No conversion to TOE was required for image
quality. Colour flow doppler quality was optimal for 82.7% and no more
than mild PVL was seen in 91.4%. 2 cases could not be excluded for PVL
due to poor image quality, but other forms of assessment were used such
as fluoroscopy, aortic root injection, and invasive haemodynamics. Poor
image quality was not associated with moderate PVL. [14] Zaouter et
al observed the outcomes echocardiography findings of patients receiving
TAVI with either CS or GA. With the degree of PVL being assessed in GA
patients via TOE and in CS patients via haemodynamics measure and
fluoroscopy. Procedural success was similar between groups. The
incidence of moderate to severe PVL after implantation was rare. There
was no difference in the incidence of moderate to severe PVL after the
procedure and at 5 days between the groups. 5 patients died during the
procedure with 3 cases in the GA group and 10 patients died during
hospital stay with 6 in the GA group and 4 in the CS group. In hospital
mortality was greater in the GA group, however there was no difference
at 30 days and 1 year. [15] Sherifi et al studied the echo findings
of patients undergoing TAVI. Patients were sedated and had either a TOE
(48 patients) or TTE (96 patients). Groups were not different in terms
of patient characteristics such as age, BMI or co-morbidities. Device
success was 98% in the TOE group and 94% in the TTE group. The median
procedure time, fluoroscopy time and rate of procedural acute kidney
injury was lower in the TOE group. There was no statistical difference
in post TAVI AR in both groups. There were 3 complications detected
early in the TOE group and managed successfully. [16]