Influence of Location and Size of Myocardial Infarction on Post-infarction Remodelling

Transcription

1 Influence of Location and Size of Myocardial Infarction on Post-infarction Remodelling Masci PG, MD ; Ganame J, MD ; Francone M, MD, PhD # ; Desmet W, MD ; Iacucci I, MD # ; Barison A, MD ; Carbone I, MD # ; Lombardi M, MD ; Agati L, MD, PhD # ; Janssens S MD, PhD ; Bogaert J, MD, PhD Fondazione CNR/Regione Toscana G. Monasterio, Pisa - Italy Gasthuisberg University Hospital, Leuven Belgium # University La Sapienza, Rome Italy European Society of Cardiology Paris, August 2011 No Conflict of Interest to Declare

2 Background In patients with acute ST-segment elevation myocardial infarction (MI) the anterior location of infarction is associated with worse prognosis TIMI-risk score for acute STEMI GUSTO-I Lee et al. Circulation 1995 Morrow, Braunwald et al. Circulation 2000

3 Background However It is still disputable whether the worse post-infarction LV remodelling and prognosis associated with anterior MI is due to greater MI size or whether infarct location exerts a role further than MI size Several studies indicated an independent contribution of MI location based on the fact that anterior MI had similar cardiac enzymatic release but worse LV remodeling and prognosis than non-anterior MI patients In contrast Other studies showed that the anterior MI location was associated with larger infact size which in turn accounted for the worse post-infarction LV remodelling and prognosis Hands et al. Circulation 1986, Thanavaro Circulation 1982

4 Background Cardiovascular Magnetic Resonance Retrospective determination of area-at risk (AAR) T2-weighted Quantification of myocardial necrosis/post-infarction fibrosis (LGE) LGE imaging Quantification of ventricular volumes, geometry and funciton Cine imaging

5 Aims To evaluate the relationship between the location and size of infarction and their reciprocal influences on post-infarction LV remodeling by prospectively studying a cohort of patients with first-time reperfused acute ST-segment elevation MI by means of a comprehensive cardiovascular magnetic resonance (CMR) approach

6 Methods Study Population: Between may 2006 and january 2009 a cohort of 260 patients with acute ST-segment elevation MI treated by primary PCI within 12- hour from symptoms onset were enrolled in 3 tertiary referral hospitals (Leuven Rome Pisa) and studied by CMR at 1-week (acute phase) and 4-month (chronic phase) after the acute event Exclusion criteria: a) Prior MI or revascularization; b) permanent atrial fibrillation; c) cardiogenic shock; d) renal failure (plasma creatinine >2mg/dl); e) CMR contraindications

7 Gd Adm Methods - Protocol Imaging - 3 min 7 min T2-w STIR image LGE image Scout T2-w STIR FSE Early post-gd Img Cine Img LGE Myocardial Salvage Index (MSI) = [ AAR extent MI size ] / AAR extent Area at-risk (only at acute phase) Microvascular Obstruction Volumes, Mass, Function Infarct/scar Size

8 Results Baseline Characteristics Anterior MI Non-anterior MI P-value (n=127) (n=133) Age (years) 58±11 59± Male n,(%) 102 (80) 116 (87) 0.13 Cardiovascular risk factors n,(%) smoke 68 (53) 76 (57) 0.34 familial history of CAD 56 (44) 50 (38) 0.22 diabetes mellitus 18 (14) 15 (11) 0.51 hypertension 49 (38) 58 (44) 0.50 hyperlipidemia 70 (55) 64 (48) 0.21 Systolic BP (mmhg) 134±25 134± Diastolic BP (mmhg) 81±14 79± Heart rate (bpm) 75±19 65±17 <0.001 Time to reperfusion (min) 268± ± Peak troponin I (µg/l) 71 [25-136] 60 [25-99] 0.21 TIMI flow-grade pre-pci n,(%) /1 86 (68) 102 (77) 2/3 41 (32) 31 (23) TIMI flow-grade post-pci n,(%) /1 5 (4) 2 (1) 2/3 122 (96) 131 (99)

9 Results Measurements Anterior MI Non-anterior MI P-value (n=127) (n=133) Baseline MSI 0.40± ± AAR (% of LV) 32±16 24±13 <0.001 MI size (% of LV) 19±12 14± MI transmurality (%) 78±25 72± MO n,(%) 62 (47) 60 (45) 0.71 MO size (% of LV) 4±3 3± LV-EDV (ml) 151±39 152± LV-ESV (ml) 79±29 76± LV-mass (g) 124±30 122± LV-WSMI 1.72± ± LV-EF (%) 48±9 51± Follow-Up MI size (% of LV) 14±9 9±7 <0.001 MI transmurality (%) 67±27 63± LV-EDV (ml) 161±46 156± LV-ESV (ml) 83±36 74± LV-mass (g) 110±24 110± LV-WMSI 1.55± ± LV-EF (%) 50±11 54±

10 Results MSI=0.61 AAR=23% of LV MI size= 9% of LV MSI=0.62 AAR=13% of LV MI size= 5% of LV

11 Results

12 Results Adverse LV remodeling 15% increase of LV-ESV volume during FU Dependent Variable: Adverse LV remodeling Baseline Variables Odds Ratio (95% CI) P-value Model A MI location(anterior vs non-anterior MI) ( ) MI size(% of LV) ( ) <0.001 Model B MI location(anterior vs non-anterior MI) ( ) MI size(% of LV) ( ) MI location by MI size ( ) Model C MSI MI size(% of LV) ( ) <0.001 MO extent(% of LV) MI location(anterior vs non-anterior MI)

13 Results Dependent Variable: LV ejection-fraction at 4-month follow-up Baseline Variables β-coefficient P-value Model A MI location(anterior vs non-anterior MI) MI size(% of LV) <0.001 Model B MI location(anterior vs non-anterior MI) MI size(% of LV) <0.001 MI location by MI size Model C Gender(female) Time to reperfusion(min) TIMI flow pre-pci(0,1 vs 2,3) MSI MI size(% of LV) <0.001 MO extent(%of LV) MI location(anterior vs non-anterior MI) LV-EDV(ml) LV-EF(%) <0.001

14 Results P=NS P=0.001 P=0.23 P=0.01 AAR/MI size =57/55% of LV LVEDVbas/FU =164/201 ml LVESVbas/FU =97/117 ml LVEFbas/FU =41/40%

15 Conclusions Patients with anterior MI experienced more extensive post-infarction LV remodelling and dysfunction than those with non-anterior MI due to larger amount of irreversible ischaemic LV damage intrinsic to anterior infarcts without any independent contribution of MI location. Accordingly, the size of baseline MI estimated by LGE imaging but not its location is an independent predictor of post-infarction LV remodelling and dysfunction at four months follow-up.

16 Partecipants