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MDCT’s role in pre-‐cardiovascular
procedure planning
Stephen CW Cheung Radiology, Queen Mary Hospital, Hong Kong
Use of MDCT before procedures
• MDCT has expanding and increasing important role in the planning of various endovascular procedures. – PCI, especially complicated lesions and CTO – TAVI – LAA closure – Cardiac re-‐synchronisaLon
Other procedures
• Re-‐do cardiac surgery • Closure of para-‐prostheLc heart valve leakage • Mitral valve indirect annuloplasty.
Re-‐do procedures
Re-‐do cardiovascular procedures: CABG-‐Valve
• ReoperaLon for cardiac condiLons are geQng more prevalent – >10% of all MVR in US – CABG seems to be declining (6% in 2000, 3.4% in 2009)
– associated with increased morbidity and mortality. • progression of disease condiLons • advanced paLent age • risks introduced by previous surgery which can potenLally be well evaluated by preoperaLve imaging using MDCT.
Risk of redo MVR
• Mortality quoted: 6-‐18% • Injury to cardiac structure: 5-‐10%
High risk findings on MDCT include:
• Bypass grac crossing the midline <1cm from posterior surface of sternum or fixed to sternum
• Close proximity of the RV or adjacent pericardium to the chest wall, <1cm.
• Ascending aorta <1cm to the inner edge of chest wall or sternum.
• Excessive length of the LIMA grac or one not adequately mobilised.
RV dilataLon, VSD,RCA close to sternum
LIMA relaLon to sternum/chest wall
AddiLonal factors to consider:
• 1. SVG disease where manipulaLon can cause distal embolisaLon.
• 2. Incidental lung or mediasLnal mass, incidence ~10% in this paLent group.
• 3. Evidence of previous mediasLniLs or dense adhesions.
ImplicaLon on operaLon • A retrospecLve study conducted by Kamdar et al in 2008
shows one or more of these features are observed in 49% of paLents, cohort size= 167. The most common finding is finding 1, noted in 38% of paLents.
• These CT findings have impact on surgical approach, with 7 paLents had the surgery cancelled.
• In 88 paLents (55% of the remaining 160 paLents) the surgeons adopted some form of prevenLve measures – non-‐midline incision eg. R thoracotomy (n=14) – deep hypothermic circulatory arrest (n=7) – peripheral cardiopulmonary bypass before incision (n=18) – peripheral arterial and venous dissecLon before incision (n= 83).
ImplicaLon on operaLon
• Another study looking for similar CT features find that MDCT before the operaLon is associated with – shorter perfusion and cross clamp Lme – shorter ICU stay – less frequent perioperaLve MI • (Maluenda et al 2010)
USG to measure CFA/CFV
• Ensure the vessels are of adequate size for cannulaLon in peripheral cardiopulmonary bypass
Ann Thorac Surg 2013;96:1358-‐66
Ann Thorac Surg 2013;96:1358-‐66
Re-‐do MVR has low mortality, morbidity and intraopera7ve injury with careful planning
Para-‐prostheLc Heart Valve Leak
Assessment of para-‐prostheLc valvular leak
• Paravalvular leak is esLmated to occur in 3-‐12.5% of prosthesis within a few years of operaLon.
• With the large number of procedures done every year, the number of leaks requiring treatment is increasing.
• With the advent of percutaneous closure instead of re-‐operaLon, high quality imaging is needed.
• 2D/3D TEE is usually the main state of imaging while CT is also gaining greater importance-‐ crescent shaped
CT of para-‐prostheLc valvular leak
• In a small study consisted of 20 paLents, MDCT has been used to evaluate para-‐prostheLc aorLc valve leak and regurgitaLon. Excellent correlaLon was found between MDCT determined regurgitaLon orifice area and echocardiogram/surgical findings.
• However beam hardening artefacts are significant and depend on type of prosthesis, rendering 12 of these subjects non-‐evaluable. – SJM standard √ – SJM HP, SJM Regent ×
CT of para-‐prostheLc valvular leak
• MDCT detecLon of paravalvular leak – Clock-‐face view – Surgical
• used as a guidance during fluoroscopy for passing guidewire and deployment of vascular plugs
Paravalvular leak
MV AV
Recent Case
Paravalvular Leak
Paravalvular leak locaLon
Paravalvular Leak locaLon
Carlos Ruiz, JACC 2011 (21)
Para-‐valvular pseudoaneurysm Just caudal to AV annulus
Percutaneous MV Repair
Development of veins
Greater and Lesser cardiac venous systems • Lesser CVS – Thebesian veins, common at ventricular apex and base of papillary muscles
– Drain most of RV, LA, RA – Can be dilated acer MI – Not septal defects
• Greater CVS – CS and non-‐CS tributaries – Drain LV, part of RV
Veins of LA Wall • Septal veins of LA drain into RA through the septum
• Most common is antero-‐superior septum
• They are not septal defects or fistulas
PFO
Anterosuperior veins
Posteroinferior veins
Veins of LA Wall
Interatrial muscle connecLon
CS System
AIV= anterior interventricular vein MCV=IIV (inferior interventricular vein) Between AIV and IIV: several lateral and posterior branches
GCV
Usually pass over the LAD and LCX but can be under
Assessment for percutaneous mitral valve repair Indirect Annuloplasty
• Percutaneous repair of MV can be performed by placing device inside the great cardiac vein and coronary sinus aiming at providing inward pressure on the mitral annulus to achieve beser leaflet apposiLon. – Reduce septal lateral dimension
Monarc system
• Coronary artery compression • 30% • MI
Viacor
CARILLON
Assessment for percutaneous mitral valve repair
• The course of the lec circumflex artery and OM branches are of potenLal importance since excessive pressure on these arteries can result in ischemia. – GCV and OM
• There is significant anatomical variaLon in the cardiac venous anatomy and relaLon of the coronary sinus to the mitral annulus. – PTOLEMY Trial: 9/29 subjects excluded
Heart 2011:97
Assessment for percutaneous mitral valve repair
Annulus calcificaLon Annulus size CondiLons of the leaflets
Cardiac ResynchronizaLon Therapy
Semitransparent volume Include bony landmarks Angle similar to that used in fluoroscopy
AP view
RAO view
LAO view PACE 2009;32:323-‐329
Detailed mapping with CT
Avoid placement in infarct zone
Absence of a vein can be due to infarct in the same region
Measurements Angle of entrance to CS and size of osLum
Vein of Marshall (Oblique vein of LA)
• Persistent LSVC • Define the boundary of GCV and CS • Seen in 35-‐40% of CT • Increased risk of perforaLon if entered during CRT
Venous valves • Can hinder advancement of guidewires/leads • May not be well seen on CTA • Seen as a depression on the outer surface – Thebesian valve at CS origin – Valve of Vieussens at CS/GCV juncLon
Thank you