1. Predicting Perioperative MI: A Revisit Homer Yang Professor & Chair Department of Anesthesia

2. Objectives Is knowing the coronary anatomy preop enough in predicting MI?Is knowing the coronary anatomy preop enough in predicting MI? Preop Stratification & limitationsPreop Stratification & limitations A “re-look”A “re-look” –Identify population for majority of periop cardiac complications –Other factors

3. Ellis et al. Am J Cardiol 1996; 77: 1126 - 28 Angiographic Correlates of Peri-op Cardiac Death & MI  case-control study  between 1984 and 1991: aortic, femoral- popliteal, and femoral-tibial surgery  between 1989 and 1991: carotid endarterectomy  1242 patients  21 with pre-op angio + in-hospital death / MI  1:2 ratio of control on basis of age, year, & Sx

4. Ellis et al. Am J Cardiol 1996; 77: 1126 - 28 Angiographic Correlates of Peri-op Cardiac Death & MI  angiography performed a median of 6 days pre-op  14 / 21 had identifiable stenosis  8 / 14 had inadequate collaterals  0 / 14 had stenosis 70 - 99%  7 / 21 had no culprit sites  high grade stenosis may have pre-op CABG / PTCA  retrospective study without CPK or troponin assays (underestimation)

5. Can we predict MI? 70 - 80% of coronary thrombosis occur where stenosis is previously insignificant70 - 80% of coronary thrombosis occur where stenosis is previously insignificant –Little et al. Circulation 1988; 78:1157 - 66 –Webster et al. JACC 1990; 15:218A –Giroud et al. Am J Cardiol 1992; 69:729 - 32

6. Davies MJ et al. Eur Heart J 1989; 10:203 - 8 Plaque Fissure in DM & HBP patients 168 test subjects who “died within 6 hrs of onset of any symptoms in their last illness”168 test subjects who “died within 6 hrs of onset of any symptoms in their last illness” 129 controls who “died suddenly and in whom autopsy showed non-cardiac deaths”129 controls who “died suddenly and in whom autopsy showed non-cardiac deaths” –69 with an atheroma related disease Cause of death: intracrebral hemorrhage, ruptured AAACause of death: intracrebral hemorrhage, ruptured AAA –60 with no atheroma related disease Cause of death: traffic accidents, suicideCause of death: traffic accidents, suicide

7. Davies MJ et al. Eur Heart J 1989; 10:203 - 8 Test subjectsTest subjects –19% had no new acute lesions –7.7% plaque fissure –43.5% mural thormbi but not occlusive –29.8% occlusive thrombi Atheroma related deathsAtheroma related deaths –16.7% plaque fissure –5% mural thrombi Non-atheroma related deathsNon-atheroma related deaths –8.7% plaque fissure Plaque Fissure in DM & HBP patients

8. Dawood et al. Intern J Cardiol 1996; 57:37 - 44 Periop MI (30 days postop) 42 vs Non-periop MI 25Periop MI (30 days postop) 42 vs Non-periop MI 25 Periop MI (42)Periop MI (42) –Subendocardial MI 13 (31%) –Circumferential 3 (7%) Plaque rupture, plaque haemorrhage, & intraluminal thrombus (one or more) 23 (55%)Plaque rupture, plaque haemorrhage, & intraluminal thrombus (one or more) 23 (55%) 19 (45%) have no identifiable plaque rupture or intraluminal thrombus19 (45%) have no identifiable plaque rupture or intraluminal thrombus Formation of thrombus at or in the immediate distal vicinity or atheroma was considered indirect evidence of plaque disruption.Formation of thrombus at or in the immediate distal vicinity or atheroma was considered indirect evidence of plaque disruption. “Severity of preexisting underlying stenosis did not predict the resulting infarct territory”“Severity of preexisting underlying stenosis did not predict the resulting infarct territory” Fatal Periop MI

9. Circulation 2009; 119:2936-44

10. JACC 2007; 50(17):1707-32

11. Circulation 1999; 100:1043-9 Lee’s RCRI In Validation CohortIn Validation Cohort Class 1, 0 factors, 0.4% cardiac complicationsClass 1, 0 factors, 0.4% cardiac complications Class 2, 1 factors, 0.9%Class 2, 1 factors, 0.9% Class 3, 2 factors, 7%Class 3, 2 factors, 7% Class 4, ≥ 3 factors, 11%Class 4, ≥ 3 factors, 11%

12. Database Results HHSC Chart Audit 1996 – 1997 elective THR & TKRHHSC Chart Audit 1996 – 1997 elective THR & TKR –679 charts –38/49 (77.5%) cardiac complications in Detsky 0 or 5 LHSC Referral ConsultsLHSC Referral Consults –2035 patients –95/130 (73.0%) of MI, unstable angina, CHF, or death in Detsky stratum 1 TOH 2002 – 2006 elective THR & TKRTOH 2002 – 2006 elective THR & TKR –5158 patients in Data Warehouse

13. Anesthesiology 2009; 111(4): 690-4 Effect of β-blockers in Postop Hip & Knee Replacements 23 (5.0–106)14 (0.3%)2 (2.6%)Class IV 38 (19–75)63 (1.2%)15 (19.5%)Class III 10 (6.1–17)502 (9.9%)32 (41.6%)Class II 4502 (88.6%)28 (36.4%)Class I ORNo POMI (n=5081)POMI (n=77)

14. Lindenauer et al. NEJM 2005; 353:349 - 61 Periop β-blocker & mortality after major non-cardiac surgery (Propensity Analysis) Retrospective cohort of patients undergoing major non-cardiac surgery in 329 hospitals in 2000 & 2001Retrospective cohort of patients undergoing major non-cardiac surgery in 329 hospitals in 2000 & 2001 782969 patients, 663635 without contraindications to β-blockers782969 patients, 663635 without contraindications to β-blockers 13454 mortality (2%)13454 mortality (2%) Number of RCRI factorsNumber of RCRI factors –0: 313969 –1: 76983 –3: 15655 –≥ 4: 1416

15. Lindenauer et al. NEJM 2005; 353:349 - 61 Perioperative Mortality 541297 (did not receive  -blockers) 10771 (1.98%) RCRI Factors ≤ 1RCRI Factors ≥ 2 8443 (1.73%) 2328 (4.23%) 78% of all mortality 22 % of all mortality

16. Emergency Sx CRI: 4 pointsCRI: 4 points Detsky’s: 10 pointsDetsky’s: 10 points RCRI: only on elective SxRCRI: only on elective Sx Ottawa Hospital Chart Audit 2003Ottawa Hospital Chart Audit 2003 –88 perioperative MI or cardiac arrest –42 after urgent or emergent surgery

17. Anesthesiology 2009; 111(4): 690-4 Effect of β-blockers in Postop Hip & Knee Replacements THR & TKR at The Ottawa Hospital (2002 – 2006)THR & TKR at The Ottawa Hospital (2002 – 2006) On day of Sx:On day of Sx: –I: β-blockers & continued during stay or until POD 7 –II: β-blockers but d/c during stay –III: No β-blockers N = 5158 patients; Mortality 54 (1.0%); POMI 77 (1.5%)N = 5158 patients; Mortality 54 (1.0%); POMI 77 (1.5%) Withdrawal of β-blockers postop is associated with POMI [OR 10; 5.8 – 18]Withdrawal of β-blockers postop is associated with POMI [OR 10; 5.8 – 18] Postop Hb < 100 g/L associated with POMI [OR 3.5; 1.8 – 6.8]Postop Hb < 100 g/L associated with POMI [OR 3.5; 1.8 – 6.8] Together, compound riskTogether, compound risk

18. Anesthesiology 2010; 112:25 - 33 Acute Surgical Anemia Influences the Cardioprotective Effects of β-Blockade Retrospective Review of Records between Mar 2005 – Jun 2006, 1° outcomes: MI, non-fatal CA, in-hospital deathRetrospective Review of Records between Mar 2005 – Jun 2006, 1° outcomes: MI, non-fatal CA, in-hospital death Nadir Hb – lowest Hb in first 3 days postopNadir Hb – lowest Hb in first 3 days postop 1:1 Propensity Analysis with matching1:1 Propensity Analysis with matching 4387 patients with nadir Hb4387 patients with nadir Hb –1153 (26%) received β-blockers (BB) within 24 hr postop –Propensity matching in 827 –Major cardiac event 54 (6.5%) in BB & 25 (3.0%) in non-BB (RR 2.38; CI 1.43 – 3.96, p = 0.0009) –Hb drop > 35% BB: RR 3.5; CI 1.8 – 5.5, p<0.0001BB: RR 3.5; CI 1.8 – 5.5, p<0.0001 Non-BB: RR 2.17; CI 0.97 – 4.86, p=0.0533Non-BB: RR 2.17; CI 0.97 – 4.86, p=0.0533

19. POISE. Lancet 2008; 371:1839-47 Independent Predictors of Periop MI Independent predictorAssociation with perioperative MI Adjusted Odds Ratio (95% confidence interval) Every 10 bpm increase in baseline heart rate1.29 (1.13-1.50) Prior history of stroke2.24 (1.20-4.20) Undergoing major vascular surgery2.21 (1.15-4.25) Preoperative serum creatinine >175  mol/L (> 2.0 mg/dl) 4.33 (2.32-8.09) Age per deciles increase1.53 (1.20-1.95) emergent/urgent surgery2.94 (1.65-5.26) clinically important bleeding3.62 (2.07-6.36) MI = myocardial infarction; bpm = beats per minute; clinically important bleeding (i.e., bleeding that was disabling or required > 2 units of blood)

20. Summary Most cardiac complications (& mortality) occur in lower risk patientsMost cardiac complications (& mortality) occur in lower risk patients Most MIs do not occur at sites of previous highest stenotic areas, in angio & in autopsy studiesMost MIs do not occur at sites of previous highest stenotic areas, in angio & in autopsy studies –Approx 16% of plaque fissure occurring in asymptomatic patients as a “baseline” Significant % of POMI due to Supply & DemandSignificant % of POMI due to Supply & Demand –45% of periop cardiac deaths are not explained by intraluminal or occlusive thrombi: supply & demand –At least 7 – 19% of periop MI on autopsy are circumferential or multi-site (supply & demand) –Is supply & demand a postop problem?

21. Conclusion Preop ACC / AHA guidelines appropriatePreop ACC / AHA guidelines appropriate Diagnosing CAD does not equal predicting perioperative cardiac eventsDiagnosing CAD does not equal predicting perioperative cardiac events “Low Risk” Patients are neglected“Low Risk” Patients are neglected Factors to watch forFactors to watch for –Postop Hb –Emergency cases Needs more research, especially in postop periodNeeds more research, especially in postop period

22. Winterlude 2012, Feb 4 – 5 Ottawa, Canada