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Coronary bypass surgery improves global and regional left ventricular function following thrombolytic therapy for
D J Kereiakes1, R M Califf, B S George
1Christ Hospital Cardiovascular Research Center, Cincinnati, OH.
Insights
Coronary bypass surgery in acute myocardial infarction patients improved left ventricular function post-treatment. Despite higher risk factors, bypass surgery did not increase in-hospital or long-term mortality compared to non-surgical care.
Area of Science:
- Cardiology
- Cardiac Surgery
- Interventional Cardiology
Background:
- Acute myocardial infarction (AMI) management often involves intravenous thrombolytic therapy.
- Coronary artery bypass grafting (CABG) is a treatment option for select AMI patients.
- The role of CABG in conjunction with thrombolysis requires further elucidation.
Purpose of the Study:
- To evaluate the outcomes of CABG performed after intravenous thrombolytic therapy for AMI.
- To compare the characteristics and mortality of patients undergoing CABG versus those not receiving CABG.
- To assess the impact of CABG on left ventricular function recovery.
Main Methods:
- Analysis of 1387 patients from TAMI trials receiving thrombolytic therapy for AMI.
- Categorization of patients into emergency (<24h) and deferred (>24h) CABG groups.
- Comparison of baseline characteristics, indications for CABG, and in-hospital/long-term mortality.
- Assessment of left ventricular ejection fraction and regional function using ventriculography.
Main Results:
- 22% of patients underwent CABG prior to discharge.
- Indications included multivessel disease (62%), failed angioplasty (12%), and recurrent angina (13%).
- CABG patients were older with more extensive coronary disease and poorer baseline left ventricular function, yet had similar mortality rates (7% vs 6%) compared to non-surgical patients.
- Surgical patients showed significantly greater recovery in left ventricular ejection fraction and infarct zone function.
Conclusions:
- Coronary bypass surgery in AMI patients treated with thrombolysis is associated with improved left ventricular function recovery.
- Despite higher-risk profiles, CABG does not appear to increase short-term or long-term mortality.
- CABG may offer a beneficial influence on clinical outcomes for selected AMI patients.
Abstract:
Coronary bypass surgery was performed prior to hospital discharge in 303 (22%) of 1387 consecutive patients enrolled in the TAMI 1 to 3 and 5 trials of intravenous thrombolytic therapy for acute myocardial infarction. Bypass surgery was of emergency nature (less than 24 hours from treatment with intravenous thrombolytic therapy) in 36 (2.6%) and was deferred (greater than 24 hours) in 267 (19.3%) patients. The indications for bypass surgery included failed angioplasty (12%); left main or equivalent coronary disease (9%); complex or multivessel coronary disease (62%); recurrent postinfarction angina (13%); and refractory pump dysfunction, mitral regurgitation, ventricular septal rupture or abnormal predischarge functional test (1% each). Although patients having bypass surgery were older (59.5 +/- 9.8 versus 56.0 +/- 10.2 years, (p less than 0.0001), had more extensive coronary artery disease (46% with three-vessel disease versus 11%, (p less than 0.0001), had more frequent diabetes mellitus (19% versus 15%, (p = 0.048), had more prior infarctions (p less than 0.0001), had more severe initial depression in global left ventricular ejection fraction (48.0 +/- 11.9% versus 51.8 +/- 11.9%, p = 0.0002), and regional infarct zone (-2.7 +/- 0.94 versus -2.5 +/- 1.1 SD/chord, p = 0.02) and noninfarct zone function (-0.36 +/- 1.8 versus 0.43 +/- 1.6 SD/chord, p less than 0.0001) than patients not having coronary bypass surgery, no difference in the incidence of death in hospital (7% surgical versus 6% nonsurgical) or death at long-term follow-up of hospital survivors (7% surgical versus 6% nonsurgical) was noted between groups. Surgical patients demonstrated a greater degree of recovery in left ventricular ejection fraction (3.4 +/- 9.8% versus 0.16 +/- 8.5%, p = 0.036) and infarct zone regional function (0.71 +/- 1.1 versus 0.34 +/- 0.99 SD/chord, p = 0.001) when immediate (90 minutes following initiation of thrombolytic therapy) and predischarge (7 to 14 days after treatment) contrast left ventriculograms were compared than did patients who received only intravenous thrombolytic therapy with or without coronary angioplasty. These data suggest a beneficial influence of coronary bypass surgery on left ventricular function and possibly on the clinical outcome of patients initially treated with intravenous thrombolytic therapy for acute myocardial infarction.