4.2 Spontaneous PIVSD closure
What we know about the option of occluder device is primarily based upon
empirical studies that the conventional devices were ASDo, mVSDo and
PimVSDo. There were no related articles about the comparison of
varieties of devices, so it is uncertain which type of device is the
best choice for catheterization. However, surveys such as those
conducted by Szkutnik et al[24] and Wacinski et
al[25] have shown that PimVSD is more suitable for
PIVSD owing to the particular structure (wider waist, larger disks and a
denser construction ) could occlude moderate to severe shunt in a short
period time.
The location and size of the device were detected by two-dimensional
transthoracic echocardiography (2DTTE) in a large number of studies,
with a sizing balloon to determine the size in minor cases. However, it
is taking the risk of enlargement of the defect, whether this method can
be adopted depends on the firmness of the rims and the anatomic
morphology of VSD[15,26]. Recently, several
attempts have been made to use three-dimensional transthoracic
echocardiography (3DTTE) or three-dimensional transesophageal
echocardiography (3DTEE) to assess the VSD. Many analysts now argue that
the strategy of 3DTTE/3DTEE over 2DTTE has been successful for the
evaluation of VSD following AMI, for example, argues that VSD shape and
its changes during the cardiac cycle can be visually and quantitatively
displayed. 3DTTE/3DTEE may thus be particularly useful before and during
percutaneous VSD closure[27-29].
There is still no definite conclusion about how to select the size of
the device. Data from several experienced articles have identified the
optimal diameter should be twice the size of the measured defect
diameter or at least 10 mm larger,it can prevent incomplete closure or
dislocation and embolization of the device due to continued septal
necrosis in the acute phase[30-31], in turn, the
occluder size was slightly larger than the measurable defect size in the
chronic phase[24]. As for the best timing of TCC
after AMI, there were two contrary opinions, majorities of people hold
the idea that the delay of 10-14 days may help for shaping the scarred
tissue to restore the perforation tissue and improving the NYHA
classification ,so that can acquire the better
progression[16]. The others consider the
percutaneous closure should do as quickly as possible because of
prolonging the time was not associated with the low mortality[15]. However, there was no direct evidence to
justify which choice could decrease the mortality effective. When
treated with PIVSD, one-key to success in procedure was immediate
complete or partial shunt reduction.Our data confirmed about 80.9%
shunt got to reduce after interventional surgery. Just like Calvert et
al[15] indicated that if the shunt cannot decrease
at least two thirds, the patients are most unlikely to survive either to
surgery or to discharge. Moreover, there is no apparent distinction
between a variety of occlusion devices, which depends on the edge
condition and size of defects identified by echocardiography. As a
rigorous surgical procedure requiring expertise and collaboration
between interventionists, anesthetists, and echocardiography
specialists.