Migrino and colleagues[159]inves-tigated the outcomes of the Global Use of SK and TPA for Occluded Coronary Arteries-1 trial and showed that even with early opening of the IRA within 3 h
Trang 131%, P!.05) Migrino and colleagues[159]
inves-tigated the outcomes of the Global Use of SK and
TPA for Occluded Coronary Arteries-1 trial and
showed that even with early opening of the IRA
(within 3 hours), a significant number of patients
(17%) had elevated LV ESV (LVESVIO40 mL/
m2) Early dilatation after AMI even after
success-ful reperfusion therapy strongly predicted early
and late mortality
The optimal timing of surgical
revasculariza-tion after AMI is controversial Historically,
emergent CABG after AMI had higher mortality
5% to 30%, with especially poor prognosis in
patients who had transmural (TM) infarcts
[160,161] However, early studies comparing
CABG to medical treatment showed that surgical
revascularization within 6 hours of symptom
on-set improved mortality over medically treated
nonrevascularized patients DeWood and
col-leagues [162] retrospectively studied 440 patients
who had TM AMI Starting CPB within 6 hours
of AMI decreased short-term and long-term
mor-tality and improved late event free survival
Hos-pital mortality for non-TM MI was 3.1% and for
TM MI was 5.2% Mortality for CABG within
6 hours was 3.8% versus 8.5% for CABG after
6 hours However, the average patient age was
54 with mostly single and double vessel disease,
exposing the study to criticism of selection bias
Main predictors of death were age, prior CABG,
and shock
Today’s environment is different The
popula-tion is older, multivessel disease is prevalent, and
safe alternatives such as thrombolysis and PTCA
exist The capabilities of PCI are improving A
recent study of the New York State cardiac
sur-gery registry investigated the effect of timing in
CABG after TM AMI with the goal of delineating
the optimal timing in this population as part of
a strategy to improve outcome after AMI This
was a retrospective multicenter analysis of
32,099 patients after CABG after TM AMI from
1991 to 1996 by 179 surgeons at 33 hospitals in
New York State [163] The average age was 65
with EF 46% Overall mortality CABG after
TM AMI was 3.3% Mortality decreased as time between the MI and surgery increased (Table 10) Multivariate analysis of 43 risks factors showed revascularization within 3 days of TM AMI was an independent predictor of mortality Day 3 was a point of inflection between the steep rise of mortality after early surgical intervention and the lower mortality later After 3 days, mortality rapidly approached baseline Although the risk does not return to baseline until day 7, there is no trend to statistical significance of added risk from day 3 to day 7 The conclusion was that aside from absolute indications for emergency surgical procedure (ie, persistent ischemia, me-chanical complications), a 3-day waiting period should be considered to allow this high-risk period to subside The initial 3-day window is
a period of heightened systemic inflammatory response with precipitously high C-reactive pro-tein[164] Limitations of this study include lack of uniformity among surgeons, institutions, myocar-dial protection protocols, surgical techniques, CPB methods and duration, and anesthesia (Table 11)
This study corroborates the current ACC/ American Heart Association guidelines of rescue PCI as primary treatment for AMI Waiting beyond the dangerous peri-infarct period has demonstrated survival benefit From this study, patients who had TM and non-TM AMI showed different trends in mortality over the observed time course Mortality in the non-TM group peaked at 6 hours then declined dramatically [138] Thus, CABG within 6 hours of non-TM AMI or within 3 days of TM AMI is associated with increased in-hospital mortality However, pa-tients undergoing early operation likely were more unstable or in cardiogenic shock, thus artificially elevating the mortality
Because early surgical vascularization after
TM AMI increases risk, aggressive cardiac sup-port including LVAD should be available In some patients, waiting is justified to optimize surgical outcome This requires careful patient selection, optimal timing of the operation, and
Table 10
Mortality after surgery for acute myocardial infarction
Data from Lee DC, Oz MC, Weinberg AD, et al Appropriate timing of surgical intervention after transmural acute myocardial infarction J Thorac Cardiovasc Surg 2003;125:115–9.
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