بسم ا الرحمن الرحيم
(Ahmed Rezk, MD, PhD, FFCCS (Paris Head, Cardiothoracic surgery, SGH, Aseer Coauthors: M. Bazid, Radiology Dep. Military H, SR Z. Saad, cardiology Dep. Aseer H
Albert Einstein
BACKGROUND
ď ą Surgical reconstruction (CAR: Coronary Artery Reconstruction) of
diffusely diseased vessel has been documented to be a surgical option for patients with diffuse coronary artery disease.
ď ą short and long term graft patency of such surgical technique must
be evaluated.
What is the surgical reconstruction
(CAR: Coronary Artery Reconstruction)? Graft patency assessment:
1- Invasive: CAG 2-Non-Invasive: MDCT
SURGICAL RECONSTRUCTION ((CAR: Coronary Artery Reconstruction Long arteriotomy opened all along diseased LAD . length of the ITA longitudinal incision same as length of LAD
arteriotomy.
Termino-lateral anastomosis between ITA and LAD made in such way
as to reshape LAD.
Barra JA,Bezon E, Mondine P, Resk A et al. Surgical angioplasty with exclusion of atheromatous plaques in case of diffuse disease of the LAD: 2 years' follow-up. Eur J Cardiothorac Surg 2000;17:509-514.
anastomosis part of ITA is used as an arterial on-lay
patch.
Atheromatous plaques excluded from LAD lumen
and left outside anastomosis.
Finally, 75% of new reconstructed LAD originates
from ITA wall and 25% from native artery.
Figure 1, preoperative coronary angiography showing diffuse Atherosclerotic long lesion in the LAD
Figure 2, intra-operative picture showing length of the reconstructed segment of LAD
Figure 3, intra-operative picture showing LIMA anastomosed to LAD To create surgically reconstructed segment of LAD
Graft patency assessment : CAG or MDCT???
ď ą Invasive coronary angiography (CAG) Diagnostic standard;
however in comparison with MDCT: 1- technically more demanding :
* CAG for CABG is technically more difficult than for native vessels. * With CAG, it is sometimes difficult to locate origin of grafts and explore them selectively (In one study, 93% of grafts were visualized by using CT, compared with only 86% by using coronary angiography. (MDCT.... relatively simple procedure)
2- more time consuming ( longer duration of procedure than MDCT) & more contrast agent used.
3- inpatient procedure (MDCT ... Outpatient)
4- small but significant risk of major complications ( arrhythmia, dissection of native coronary artery or bypass graft, MI, and embolic events). These complications account for 0.14 to 0.28% mortality 0.2 to 2.1% morbidity 5- It is extremely difficult to ask asymptomatic post CABG patient to have CAG to assess surgical technique? MDCT .... Reliable, noninvasive and safe alternative
Benefit of MDCT as a modality for evaluating bypass graft patency is its high sensitivity and high negative predictive value meta-analysis (Radiology, 247, 679-686, 2008) demonstrate that obstructive bypass graft disease can be detected by using at least a 16section CT with : sensitivity 98%, specificity 97%, positive predictive 93% negative predictive 99%. MDCT 64 – 320 slice…..
Methods Niagara Falls
Figure 4, intra-operative picture showing atherosclerotic load removed from LAD after open Endarterectomy. Notice the right angled atheromatous plaques removed from septal branches.
Study population & preoperative variables Prospective study :
- designed to assess graft patency of (CAR) coronary artery reconstruction - using postoperative MDCT angiography as non-invasive single tool. Study population : asymptomatic 25 patients (primary CABG). CAR, planned preoperatively in 22 patients (88%),
while in 3 patients decision made intraoperatively (decision changed from simple distal graft to reconstruction). 2
patients open reconstruction.
Endarterectomy
necessary
to
complete
Study population & preoperative variables
ď ąPreoperative echocardiogram : Severe LV dysfunction (EF below 35%) in 6 cases
ď ąPre-operative angiogram: 3-vessel disease in majority of patients (88%) 2 vessel- disease in only 3 patients (12%).
Postoperatively patients were on:
- aspirin and clopidogrel - prophylactic dose of enoxaparin during hospital stay - after discharging to home …… aspirin and Plavix. Those who underwent endarterectomy were on aspirin
and oral anticoagulant after discharge to home (INR 2.5).
Cardiac CT imaging technique and interpretation All patients underwent postoperative cardiac CT using 64 multi-
detector scanner.
Volume-rendered images initially used to visualize course of grafts in
relation to coronary arteries.
Curved multiplanar reconstructions used to identify and to classify
lesions into significantly diseased or not.
Coronary
arteries and grafts evaluated for presence of haemodynamically significant stenosis which was defined as reduction of lumen diameter by > 50%.
All patients were in sinus rhythm. Heart rate below 70 beats per minute was achieved with only
oral medication before CT angiography.
Beta blocker administration (Ivabradine added in some cases)
required in all patients to decrease heart rate to desired level.
Mean HR = 62 ± 3 beats/min.
Results
Victoria-Falls
MDCT performed without complications in any patient. A total of the 86 grafts were evaluated, consisting of
59 venous grafts 27 arterial grafts (24 LIMA and 3 RIMA grafts), all these grafts were assessed for patency and occlusion using
64-slice CT.
3 patients(12%) had 2 grafts, 11 patients (44%) had 3 grafts, 8 patients (32%) had 4 grafts, 3 patients (12%) had 5 grafts
Of 27 arterial grafts, ď ą 25 (92%) grafts were anastomosed to LAD ď ą and 2 (8%) were anastomosed to left circumflex.
The arterial grafts consisted of: * 24 LIMA to LAD as pedicled grafts. * 3 RIMA as following, - 2 RIMA to left circumflex, (1 as simple anastomosis , second one used to reconstruct short segment (2 cm) of OM) - third
RIMA implanted into LIMA (Y) and used to reconstruct LAD.
Of the 57 venous grafts, 39 were anastomosed to left circumflex, 15 to RCA and its tributaries, 3 to diagonal coronary arteries.
Radial arteries were not used in this series.
According to MDCT All arterial grafts (100%) were classified as patent . while 51 venous graft (89%) were considered as patent. All the significant stenosis were found in the body of
venous grafts.
Table 1. patency rate of arterial coronary grafts
Table 2.patency rate of venous coronary grafts
Figure 5. PREOPERATIVE CORONARY ANGIOGRAPHY: showing total LAD occlusion
.Volume-rendered image
Figure6 showing reconstructed segment of LAD (between the 2 yellow arrows). Green arrows show venous grafts to intermediate and OM coronary arteries.
Figure7. Curved multiplanar reconstructed image showing LIMA (down arrow), LIMA is joining LAD, start of reconstructed segment. Notice the smooth joining of LIMA to LAD (arrow head). Diffusely diseased LAD proximal to reconstructed segment (up arrow)
Figure8
.Volume-rendered image showing
reconstructed segment of SVG to PDA with greater than 50% proximal stenosis just after the hood of SVG .
Figure 9. Curved multiplanar reconstructed image shows greater than 50% stenosis proximal .stenosis just after the hood of SVG bypassing the PDA
Limitations of the study
Small number of patients. (we are planning to recruit more patients with more diffuse disease and more co-morbidities)
Comparison with invasive angiography was not performed (previous studies showed high accuracy of MDCT?).
2 ½ Y follow up.
mid and long-term patency rate ?.. (Patent IMA grafts will continue to be patent?)
Flow characteristics & functional state of grafts
- data obtained does not provide information about flow characteristics of grafts.
- false positive result in cases of competitive flow between bypass graft and native coronary artery.
Conclusion
Extensive reconstruction of diffusely diseased LAD using an ITA
graft could be performed safely with very encouraging results.
MDCT angiography is an excellent non invasive tool not only to
evaluate graft patency in reconstructed LAD but also to detect other findings in asymptomatic patients with diffuse coronary artery disease for better and more close follow up.
Larger comparative study
validate our findings.
with invasive CAG is required to
Extensive reconstruction of diffusely diseased LAD using an ITA
graft could be performed safely with very encouraging results.
MDCT angiography is an excellent non invasive tool not only to
evaluate graft patency in reconstructed LAD but also to detect other findings in asymptomatic patients with diffuse coronary artery disease for better and more close follow up.
Larger comparative study with CAG is required to validate our
findings.
As the island of knowledge expands, So too do the .shores of ignorance
Oryx captured in National Park in Namibia just after sunset. They are heading through the dunes in search of food and water