Management of AMI after CABG

Management of early AMI after CABG:

Management of early AMI after CABG Ri 陳怡文

Outline:

Outline Introduction Early complications of CABG Diagnosis of MI after CABG Recommendation for diagnosis Treatment of early graft occlusion Summary

Preference for IMA grafts:

Preference for IMA grafts Better graft patency(10-year) Improved patient survival reoperation for saphenous vein graft (SVG) stenosis 500,000 patients with nonemergent CABG (U.S., 1996~1999): IMA provides acute survival rate(30-day mortality) J Thorac Cardiovasc Surg 2002 May;123(5):869-80

Mechanism of complication:

Mechanism of complication Cardiopulmonary bypass (CPB) aortic instrumentation and manipulation, including cannulation, decannulation, and partial or complete clamping and unclamping Dislodgement of atherosclerotic debris and embolization from diseased aortas Technical errors: site of the distal anastomosis, Aprotinin use,… J Am Coll Cardiol 2005 Oct 18;46(8):1521-5. Epub 2005 Sep 28. J Thorac Cardiovasc Surg 1998 Nov;116(5):716-30

Other factors for complication:

Other factors for complication Global cardiac arrest Hypothermia Nonpulsatile bypass and artificial perfusion An intense "inflammatory" response to perfusion with artificial (nonendothelialized) surfaces The reintroduction of fat and particulate debris as well as procoagulant and proinflammatory factors from the pericardial surgical field into the systemic circulation via the use of cardiotomy (field) suction The sternotomy and skin incision

Outline:

Outline Introduction Early complications of CABG Diagnosis of MI after CABG Recommendation for diagnosis Treatment of early graft occlusion Summary

Early complication:

Early complication death, myocardial infarction (MI) stroke wound infection prolonged requirement for mechanical ventilation acute renal failure bleeding requiring reoperation

Outline:

Outline Introduction Early complications of CABG Diagnosis of MI after CABG Recommendation for diagnosis Treatment of early graft occlusion Summary

New Q wave & elevated cardiac enzyme:

New Q wave & elevated cardiac enzyme MI ?

Q wave MI:

Q wave MI Mean 4~5% patients, 0~10% among hospitals Occasion unmasking of previous MI Am J Cardiol 2000 Oct 15;86(8):819-24. Circulation 1983 Feb;67(2):302-9.

Risk factors:

Risk factors Cardiomegaly Long time on cardiopulmonary bypass Repeat CABG (6.1 percent in one report) CABG combined with other cardiac surgery

What new Q wave means~:

What new Q wave means~ Worse outcome 1. CASS : higher mortality in-hospital (9.7% V.S. 1.0 % 2. BARI : higher 5-year mortality rate(8.2% V.S. 3.7% for no new ECG changes, adjusted relative risk 2.6), no ↑mortality associated with other new ECG changes (ST segment elevation or depression or T wave abnormalities) Circulation 1983 Feb;67(2):302-9. Am J Cardiol 2000 Oct 15;86(8):819-24.

Elevated cardiac enzyme:

Elevated cardiac enzyme myocardial necrosis & routine sequela of the procedure serum CK-MB↑ above the upper limit: 62 to 90% MI diagnosis need EKG changes Implicate MI  Worse outcome

What range signify?:

What range signify? 2918 patients, CKMB elevation, 6-month mortality < 5 times: 3.4% 5~10 times: 5.8% 10~20 times: 7.8% >20 times: 20.2% this relationship remained significant after adjusting for other risk factors J Am Coll Cardiol 2001 Oct;38(4):1070-7.

What range signify?:

What range signify? 3812 patients: >10 times elevation of CKMB  increase mortality Significantly Increase mortality  average 3-year Reflect early graft failure, inadequate myocardial protection during bypass, and/or distal embolization of plaque material J Am Coll Cardiol 2002 Dec 4;40(11):1961-7 .

Troponin:

Troponin more specific and sensitive markers than CK-MB of a new MI after CABG More predictive of early complication

Troponin:

Troponin 224 patients, TnT & CK-MB check Q8H after op, multivariable analysis troponin T≥ 1.58 ng / mL  strongly predictve of death or shock, post-op 18~24hrs CK-MB: No independent prognostic importance when TnT was measured J Am Coll Cardiol 2002 May 1;39(9):1518-23.

Outline:

Outline Introduction Early complications of CABG Diagnosis of MI after CABG Recommendation for diagnosis Treatment of early graft occlusion Summary

Recommendation for diagnosis:

Recommendation for diagnosis Review of over 10,000 patients with CABG or PCI (1998) Routine check EKG, CK, CKMB at pre-OP & post-OP(8~16hrs) CKMB > 5-fold of ULN  treated as MI < 5-fold  uncertain Troponin T levels are more useful markers (2002)

Outline:

Outline Introduction Early complications of CABG Diagnosis of MI after CABG Recommendation for diagnosis Treatment of early graft occlusion Summary

Early graft occlusion:

Early graft occlusion Early (within the first 30 days after surgery) occlusion 5~10% of saphenous vein grafts Thrombotic technical problems at the anastomosis injury related to manipulation during harvesting

Early graft occlusion:

Early graft occlusion 3~6% p’ts: ischemic symptoms , significant ischemic ECG abnormalities , hemodynamic instability , and/or ventricular arrhythmias Aspirin therapy reduced risk: typical within 6 hrs after OP

OBJECTIVE:

OBJECTIVE immediate angiography defined clinical and laboratory criteria of perioperative myocardial infarction after coronary artery bypass operation

METHODS:

METHODS January 1999 and December 1999 2052 patients underwent coronary artery bypass grafting 131 (6.4%) patients met the criteria of perioperative myocardial ischemia

CRITERIA:

CRITERIA (CK/CK-MB) ↑above 10% ischemic EKG episodes: new onset of elevated ST-segment change lasting at least 1 min and involving a shift from baseline of greater than or equal to 0.1 mV of ST-depression and a new association of a postoperative Q recurrent episodes of, or sustained ventricular tachyarrhythmia as well as ventricular fibrillation hemodynamic deterioration despite adequate inotropic support

RESULTS:

RESULTS 108 patients (5.3%, group A): Angiography 23 patients (1.1%, group B): re-operated

GROUP A(108):

GROUP A(108) Regular grafts in 45 patients (2.2%) 63 patients (3.1%) - an occlusion (n=41) incorrect anastomosis (n=29) graft stenosis (n=14) graft spasm (n=6) displaced graft (n=6) poor distal run-off (n=5) incomplete revascularization (n=2)

GROUP A(108):

GROUP A(108) 43 patients received… re-operation (34 patients) an early angioplasty (nine patients) 45 patients: patent 20 patients: poor coronary artery

Group B(23):

Group B(23) graft occlusion: 10(43.5%) incorrect anastomosis: 5(21.7%) bleeding, stretched graft, venous graft spasm and displaced graft: 1 each(4.3%) no patho-morphological:4 (17.4%)

Thirty-day mortality :

Thirty-day mortality group A(108): 10 (9.3%) All of them with angiographic findings group B(23): 9(39.1%) All graft occlusion, MI, elevated CK/CKMB ratio, significant ST change, new Q waves confirmed

CONCLUSION:

CONCLUSION ST-change and elevated CK/CK-MB enzyme ratio is highly indicative for possible graft failure and should be followed early angiographic control to assess the need for reintervention.

Method:

Method 1990 ~ 1995 2003 patients underwent an isolated CABG operation Acute coronary angiography  stable patients; Haemodynamically severely compromised  operating room.

Selection criteria for myocardial ischemia :

Selection criteria for myocardial ischemia New changes in the ST-segment in the ECG a CKMB value greater than 80 U/L new Q-waves in the ECG recurrent episodes of, or sustained ventricular tachyarrhythmia ventricular fibrillation haemodynamic deterioration and left ventricular failure.

RESULTS:

RESULTS 71 (3.5%) patients of all CABGs with suspected graft failure acute re-angiography (n = 59; group 1) immediate re-operation (n = 12; group 2)

Group 1(59):

Group 1(59) the acute re-angiography demonstrated graft failure/incomplete re-vascularization in 43 patients (73%). The angiographic findings were: Occluded vein graft(s) in 19 (32%); poor distal run-off to the grafted coronary artery in ten (17%); internal mammary artery stenosis in four (7%); internal mammary artery occlusion in three (5%); vein graft stenoses in three (5%); left mammary artery subclavian artery steal in two (3%); and the wrong coronary artery grafted in one (2%).

Group 2(12):

Group 2(12) Graft occlusion: 11 No evident cause of circulatory collapse: 1

30-day mortality:

30-day mortality Group 1 (59): 3 (7%) Group 2(12): 6 (50%)

Conclusion:

Conclusion An acute re-angiography demonstrated graft failure or incomplete re-vascularization in the majority of patients with myocardial ischaemia early after CABG. Re-operation for re-re-vascularization was performed with low risk. Few patients with circulatory collapse could be saved by an immediate re-operation without preceding angiography.

Slide 44:

Am J Cardiol. 2006 Mar 15;97(6):789-91. Epub 2006 Jan 11.

Slide 45:

Am J Cardiol. 2002 Nov 1;90(9):1009-11.

Risk of re-OP:

Risk of re-OP High mortality Emergent OP without acute angiography  no assessment

Risk of PCI:

Risk of PCI Rupture Bleeding Need specific timing, caution for high-pressure ballon…

The optimal revascularization strategy for early graft occlusion is not known.:

The optimal revascularization strategy for early graft occlusion is not known.

Recommendation:

Recommendation

Recommendation:

Recommendation Acute angiography for re-op assessment Emergent cardiac catheterization for patients developing acute ischemia soon after CABG Caution for treatment of fresh anastomoses Treat possible perforations

Recommendation:

Recommendation low pressure balloon angioplasty for early treatment of distal anastomoses drug-eluting stents for severe thombosis GP IIb/IIIa inhibitors and clopidogrel loading treat bleeding complications

Summary:

Summary ST-change and elevated CK/CK-MB enzyme ratio is highly indicative for possible graft failure New Q wave and >10 times elevation of CKMB  increase mortality Troponin T: more specific and sensitive markers than CK-MB of a new MI after CABG

Summary:

Summary Acute angiography when the patients meet clinical or laboratory criteria: New changes in the ST-segment in the ECG a CKMB value greater than 80 U/L new Q-waves in the ECG recurrent episodes of, or sustained ventricular tachyarrhythmia ventricular fibrillation haemodynamic deterioration and left ventricular failure.

Summary:

Summary Acute angiography for re-op assessment helps decrease in-hospital mortality Early PCI (30 days) salvages more myocardium Caution for complication of perforation and bleeding during PCI There was no consensus about whether reoperation or PCI pose more benefit; it depends on individual basis

Thanks for your attention !:

Thanks for your attention !