Left main coronary artery (LMCA): The proximal segment

Transcription

1 Anatomy and Pathology of Left main coronary artery G Nakazawa Tokai Univ. Kanagawa, Japan 1

2 Anatomy Difinition Left main coronary artery (LMCA): The proximal segment RCA AV LAD LM LCX of the left coronary artery that arises from the left aortic sinus just below the sinotubular junction to its bifurcation into the LAD and LCX LMCA is responsible for supplying approximately 75% of the left ventricular cardiac mass

3 Anatomy LMCA is generally divided into 3 anatomic regions 1.Ostium (Origin of LMCA from aorta) 2.Middle portion 3.Distal (Bifurcation) i portion Approximately one-third of cases have trification The Average length of LMCA: 10.8±5.2mm (2-23mm) 23mm) The Average angle of terminal brunches: 87±29 ( ) Positive correlation: length and angle Reig Jetal al. Clin Anat 2004

4 Anatomy Specific Features Ostium portion of LMCA is rich in aortic smooth muscle cells and elastic fibers Elastic recoil Bifurcation at the distal portion Flow disturbance (Susceptible to develop the plaque) Procedural Complexity

5 Anatomic features and the development of atherosclerotic plaque in left main coronary artery: IVUS data Short LMCA (<10mm) (n=44) Long LMCA ( 10mm) (n=43) Ostium 55% 18% Stenosis Location Middle 7% 5% Distal bifurcation 38% 77% Ostial stenosis (n=32) Non-ostial stenosis (n=55) Morphologic Findings Lumen area (mm 2 ) Plaque burden (%) Remodeling index Maehara A, et al. Am J Cardiol. 2001;88:1-4.

6 Plaque Formation Luminal Narrowing Mean cross sectional luminal narrowing, left main, by age, sudden coronary death Mean % stenosis < > 70 N=194 yrs yrs yrs yrs yrs Data from CVPath sudden cardiac death registry

7 Plaque Formation in LMCA Maximal cross sectional luminal narrowing, 194 cases of sudden coronary death % narrowing Location of stenosis (>75%) unclassified distal diffuse proximal middle 0 < 25% 25-50% 50% 50-75% >75% N=194

8 Patients with >75% LM stenosis Proximal LAD and/or LCX involvement 54 Male, sudden death LMCA LM+LCX (33%) LM+LAD (27%) LM only (7%) LM+LAD+LCX (33%) Proximal LAD Proximal CX

9 Plaque Progression in LMCA PIT Early NC Late NC TCFA

10 Advanced plaque in LMCA Intraplaque hemorrhage Erosion Plaque rupture Thr Thr NC Thr Hemorrhage

11 Types of plaque in LMCA in sudden coronary death cases All sudden coronary death cases (n=374) 4% 5% 3% 2% 2% 1% 2% Pathologic intimal thickening (157) Fibroatheroma (82) Fibrocalcific (63) Adaptive intimal thickening (19) 42% Fibrous plaque (13) 17% Healed rupture (12) Acute rupture / fissure (8) Fatty streak (8) Nodularcalcification(6) 22% Thin cap fibroatheroma (5) Erosion (1)

12 Types of plaque in LMCA in sudden coronary death cases with stenosis 50% Cases with stenosis 50% in sudden coronary death (n=171) 6% 4% Fibroatheroma (53) 3% 3% 3% 2% Fibrocalcific (45) 31% Pathologic intimal thickening (38) Healed rupture (10) Nodular calcification (6) 22% Acute rupture / fissure (5) Thin-cap fibroatheroma (5) 26% Fibrous plaque (5) Fatty streak (3) Erosion (1)

13 LM Length and Luminal Narrowing, Calcification Sudden coronary death victims with LM luminal narrowing 50% (n=71) LM Prox LAD Prox LCX (%) 90 Luminal area stenosis of LM p=0.032 LM length (mm) <10 (n=20) 80 10, <15 (n=35) LM length LCX (n=16) 60 LAD 5 mm 50 LM length (mm) Longer left main had severe luminal narrowing. Calcification (% Area) (%) LM length (mm) 50 p=0.48 p=0.19 p=0.85 <10 (n=20) 40 10, <15 (n=35) (n=16) 20 Calcification was the greatest in 10 prox LAD and the least in prox LCX. 0 No significant relationship between LM length and calcification. Left Main Prox LAD Prox LCX

14 Plaque distribution in bifurcation lesion

15 Plaque Formation in Bifurcation High shear Low shear Main Vessel proximal A C G B D E F Main Vessel distal (mm) (mm) Plaque thickness * * * * A B C D E F G Necrotic core thickness Flow divider 0.1 * * * Side Branch 0 A B C D E F G Nakazawa G et al. J Am Coll Cardiol Apr 20;55(16): P<0.05 5, vs. A (*), vs. B ( ), vs. C &D ( )

16 Plaque Formation LM + LAD severe stenosis

17 IVUS classification for LMCA bifurcation plaque distribution Oviedo, C. et al. Circ Cardiovasc Interv 2010;3:

18 Why so susceptive to get diseased? Traub, O. et al. Arterioscler Thromb Vasc Biol 1998;18:

19 Pathology of Left Main Coronary Artery Stenting Data from CVPath Autopsy Registry

20 BMS vs DES in Autopsy Patient Characteristics BMS (n=15) DES (n=12) Age 56.0 ± ± 8.8 p=0.001 Gender (f/m) 4/11 3/9 p=0.53 Duration of Survival (days) 189 ± ± 324 p=0.98 CABG 5 6 Lesion Characteristics BMS (n=15) DES (n=12) Stent lesion length (mm) 16.2 ± ± 18.0 p= 0.02 Isolated Left Main 2 3 Bifurcation (single vessel) 11 6 Bifurcation (>2 vessels) 1 3 Indication BMS (n=15) DES (n=12) ACS/AMI 2 3 Stable Angina 13 9 Vorpahl M et al. ACC2010

21 BMS vs DES in Autopsy Pathology BMS> 30 days (n=11) DES >30 days (n=10) Duration 288 ± ± 374 P= Stent diameter 3.73± ±0.57 P= Vessel ldiameter 573± ± ±0 5.93±0.93 P= Vessel Area 19.47± ±4.61 P= Stent Area 76±1 7.6± ±2 8.51± P= Plaque Area 11.84± ±3.46 P= Lumen Area NeointimalArea %Area StenosisNeointimal Thickness P= P= P= P= BMS DES BMS DES BMS DES BMS DES Vorpahl M et al. ACC2010

22 Cause of Death at Autopsy with LMCA stenting Cause of Death BMS (n=15) DES (n=12) SRD 6 (40) 7 (58) p=0.26 NSRD 4 (26) 4 (33) NCD 5 (33) 1 (8) SRD: Stent Thrombosis/ Restenosis NSRCD: SCD and patent stent NCD: other Vorpahl M et al. ACC2010

23 LM CX Early Stent thrombosis 73F, Cypher stent implantation in LMCA Sudden death 2 days after implantation LAD Thr Thr Thr Thr Thr NC

24 Very Late Stent Thrombosis in LM stent LM LAD (PES2.5 years) LM: PES LAD: PES Diag: PES LCX: PES Lom: BMS LCx Mid Left LftMi Main Lom Diag Thr SCD seven days after discontinuation of Clopidogrel and ASS for lung biopsy. Persistent Inflammation Uncovered dstrutst Occlusive Thrombus Malapposition Fibrin Deposition 4.5 mm

25 Analysis of Bifurcation Stenting From CVPath Autopsy Cases

26 DES implantation in Bifurcation Lesion Age (yrs) Male Gender (%) Mean duration (day) >30 days (%) Technique 1 stent 2 stent, T/ V/ Crush Number of stents Restenosis MV (%) SB (%) Thrombosis < 30 days > 30 days DES (n=19) BMS (n=21) p value 61 ± ± (79) 13 (62) [188, 680] 150 [54, 540] (63) 14 (67) / 2/ 2 9/ 3/ ± ± (6) 7 (33) (16) 6 (29) 0.7 MV (%) 3 (43) 3 (43) 0.33 SB (%) 3 (43) 4 (57) MV (%) 9 (75) 5 (36) 0.04 SB (%) 5 (42) 2 (14) 0.35 Timing of thrombus 270 [195, 585] 60 [35, 105] Nakazawa G et al. J Am Coll Cardiol Apr 20;55(16):

27 Morphometric Analysis Lateral wall 1 or 2 sections Neointimal thickness Fibrin deposition Uncovered struts Flow divider Nakazawa G et al. J Am Coll Cardiol Apr 20;55(16):

28 Morphometric Analysis BMS BMS Flow divider Lateral wall p value Neointimal thickness (mm) 042± 0.42 ± ± 0.50 ± Struts t with fibrin i (%) 24 ± ± Uncovered Strut (%) 17 ± 31 5 ±

29 Morphometric Analysis DES Flow divider Lateral wall p value Neointimal thickness (mm) 0.08 ± ± Struts t with fibrin i (%) 52 ± ± Uncovered Strut (%) 48 ± ± 24 <0.0001

30 Flow disturbance induced by stenting 140 A B 120 C downstream carina upstream Pressure [mm mhg] Time [sec] D E F /min] Flow Rate [ml Time [sec] downstream (nonstented) Upstream (nonstented) G H I downstream (stented) Upstream (stented) Nakazawa G et al. J Am Coll Cardiol Apr 20;55(16):

31 Conclusions LMCA show complex plaque especially when significantly narrowed LAD and/or LCX involvement was common in patients with LMCA stenosis Atherosclerotic plaque was predominantly seen in lateral wall rather than flow divider Because of the plaque complexity, the deployment is important in LMCA stenting Flow disturbance is the primary cause of delayed arterial healing in bifurcation lesion following DES implantation