Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_3737_Библиотеки_им_академика_М_И_Перельмана

tors for erosion with the Amplatzer device are: decient rims (particularly inferior), a balloon sized stop ow diameter 5mm greater than the static diameter or a low weight to device size ratio [34]. Given the design of the Gore device, these rims may not be as necessary for erosion risk but tissue rim is needed for device stability. A decient rim from the defect to the AV valves can lead to AV valve dysfunction. There are many dif-

ASD and PFO: After the procedure, a transtho­racic echocardiography is performed to document the position of the device and a bubble study to document any residual shunting (Video 14). Though not in this case, in many cases, a tiny shunt remains, especially with provocative maneuvers. This should not by itself be a cause for alarm as most times, with endothelialization, the follow up TTE shows no residual shunting. It often takes a full year to be able to assess the nal degree of closure because endothelialazation is a slow pro­cess. Additionally, the echo should be reviewed for any sign of pericardial uid as this may be an early

new clinical events that would suggest device

5. A 38-year-old woman underwent closure of

CT Computed tomography ECG Electrocardiography LAX Long axis MPA Main pulmonary artery MRI Magnetic resonance imaging mVSD Muscular ventricular septal defect pmVSD Perimembrenous ventricular septal

1. Identify the best transthoracic echocardio-

graphic imaging planes to assess perimem­branous and muscular ventricular septal defects

2. Identify the best transesophageal echocardio-

ria for percutaneous VSD device closure, espe­cially those identied by echocardiography

A muscular VSD is a defect in the interventricu­lar septum that has exclusive muscular borders. Muscular VSDs represent the second most com­mon type of VSDs in children, accounting for approximately 10–15% of such defects [1]. They are less common in adults but can be seen after blunt chest trauma [2], as described herein. These defects are categorized according to their loca­tion as being mid muscular vs apical (in relation to the moderator band), and anterior vs posterior. They can exist as a single defect, or as multiple simultaneous defects (Swiss-cheese type of VSD, when consisting of 4 or more defects) [3].

Preprocedural evaluation is of paramount impor­tance to determine not just eligibility for percuta­neous closure of a mVSD, but also to dene the characteristics of the VSD and to plan for the best percutaneous approach, as well as to anticipate any potential post-procedural complications. Evaluation begins with a transthoracic echocar­diogram (TTE) to identify the location, number, and size of mVSDs, and to determine the pres-

ence or absence of any associated cardiac defects. Pre-procedural TTE also plays an important role in evaluating the hemodynamic signicance of mVSD through assessing the size of the left heart chambers and helps in estimating the amount of shunt (Qp:Qs). It is worth noting that most small mVSDs are often not hemodynamically signi­cant. These small mVSDs are sometimes difcult to visualize on TTE by 2D and may necessitate color Doppler evaluation. Important views to obtain by TTE for the assessment of mVSD include the parasternal short and long axis views and the 4-chamber view. The parasternal short axis view with a sweep beginning at the base of the heart and progressing to the apex is of par­ticular importance in evaluating mVSDs. In this view, posterior mVSDs will appear between 7 and 10 o’clock, mid-muscular VSDs will appear between 10 and 12 o’clock, and anterior mVSDs will appear between 12 and 2 o’clock [4]. The parasternal long axis view is also helpful to assess the location and size of mVSD with particular sweeps across the septum using color Doppler. Additional views to assess mVSD location and number include the apical 4-chamber sweep. In the apical view, visualization of the defect at the level of the atrioventricular valves indicates a posterior mVSD, whereas visualization at the level of the outow tracts indicates an anterior mVSD.In addition, the location along the long axis plane (apical vs mid vs basal) can be inter­rogated in this view. These various views are also essential to assess for left sided chamber dilata­tion and estimating the gradient across the VSD shunt. In younger patients and children, the sub­costal sagittal view is also helpful to assess the mVSD shunt and location.

Transesophageal echocardiography (TEE) plays an important intraprocedural role during mVSD closure. TEE can help with accurate siz­ing, localization of the defect (s), and identica­tion of total number of defects prior to closure. It can also be used to monitor closure through assessing the stability of the device, impingement on surrounding structures, and residual shunts post device deployment. TEE views during per­cutaneous VSD closure include a trans-gastric short axis view of the left ventricle, mid-

esophageal four chamber view, and the trans­gastric basal short axis view [5, 6]. These views are essential to evaluate the shunt location and size during the intra-operative procedure and for selecting which VSD to approach rst especially in the setting of multiple or Swiss Cheese mVSDs. TEE also provides accurate measure­ment of the size of the mVSD which is usually done by 2D and color in order to decide on the size of the device needed. After other associated abnormalities are studied and after chamber sizes and function are assessed, more imaging is per­formed concentrating on the VSD and nearby structures, namely, the papillary muscles, mod­erator band, and the chordae tendinae. The atrio­ventricular valves are interrogated at baseline for any regurgitation.

The VSD is measured in multiple views including the frontal 4-chamber and basal short­axis views. Tissue rims and distances from aor­tic and tricuspid valves are also measured in the above views to determine adequacy for device closure. The appropriate device size is usually chosen to be 1–2mm larger than the VSD size as assessed by TEE with color Doppler and angiographic evaluation (maximal size at end­diastole). During the closure procedure, the TEE mid- esophageal 4-chamber view is a help­ful home view to help guide passage of the guidewire and the delivery system across the defect into the LV cavity and to monitor the sub­sequent deployment of the LV disk followed by aligning the device in the appropriate position against the ventricular septum. This real-time monitoring of the device by TEE is essential to help the operator maneuver or reposition the device when needed and for avoiding any dam­age to close-by structures such as the mitral, tri­cuspid and aortic valves. It is also essential to check for any residual shunting and if signi­cant then to allow the operator to redeploy a larger device if needed.

Multiple surgical approaches for mVSD clo­sure have been reported including staged repair