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Intercenter variability in outcome for patients treated with direct coronary angioplasty during acute myocardial
T F Christian1, J H O'Keefe, M A DeWood
1Division of Cardiovascular Diseases and Internal Medicine, Mayo Clinic and Mayo Foundation, Rochester, MN 55905, USA. christian.timothy@mayo.edu
Insights
The success of direct coronary angioplasty for heart attacks depends on the medical center. Center performance significantly impacts heart attack size and left ventricular function, highlighting the need for standardized care.
Area of Science:
- Cardiology
- Interventional Cardiology
- Acute Myocardial Infarction Management
Background:
- Direct coronary angioplasty is a key treatment for acute myocardial infarction.
- Procedure success is influenced by resource availability and operator expertise.
- Variability in outcomes suggests a need to evaluate the impact of the performing center.
Purpose of the Study:
- To assess the influence of the medical center on direct coronary angioplasty outcomes for acute myocardial infarction.
- To control for known factors affecting treatment success.
- To identify center-specific effects on infarct size and cardiac function.
Main Methods:
- A study involving 99 patients with ST-elevation myocardial infarction treated with direct angioplasty across four high-volume centers.
- Utilized technetium-99m sestamibi SPECT imaging to quantify myocardium at risk, residual blood flow, and infarct size.
- Assessed left ventricular ejection fraction and Thrombolysis in Myocardial Infarction (TIMI) flow grade post-procedure.
Main Results:
- No significant differences were observed between centers in baseline characteristics, myocardium at risk, reperfusion time, or initial antegrade flow.
- Significant variations in mean infarct size (10-23% LV) and left ventricular ejection fraction (0.47-0.57) were noted across centers (p=0.11 and p=0.002, respectively).
- The prevalence of TIMI grade 3 flow post-angioplasty differed significantly by center (71-94%, p=0.01).
- Center of performance was an independent determinant of infarct size and LV ejection fraction after adjusting for key variables.
Conclusions:
- The effectiveness of direct coronary angioplasty in limiting infarct size and preserving left ventricular function is center-dependent.
- Standardized assessment of reperfusion therapy effectiveness in clinical practice is crucial.
- Further investigation into center-specific protocols and outcomes is warranted to improve patient care.
Background:
Direct coronary angioplasty is an effective therapy for acute myocardial infarction, but its success may be dependent on both ready availability and operator skill. The purpose of this study was to investigate the impact of the center performing direct coronary angioplasty for acute myocardial infarction while controlling for parameters known to affect outcome.
Methods And Results:
The study group consisted of 99 patients with ST elevation who were treated with direct angioplasty in four high-volume centers. Patients were injected with technetium-99m sestamibi intravenously and then taken to the cardiac catheterization laboratory. Antegrade flow was graded before and after direct coronary angioplasty. Single photon emission computed tomography was performed 1 to 6 hours after injection to measure myocardium at risk and residual blood flow to the jeopardized zone using previously published quantitative methods. A repeat sestamibi injection and tomographic acquisition were performed at hospital discharge to measure actual infarct size. There were no significant differences by center for baseline clinical characteristics, mean myocardium at risk (29% to 37% left ventricle [LV]), time to reperfusion (3.1 to 4.1 hours), residual blood flow, infarct location, or antegrade flow. Despite these similarities, there were differences in outcome measures by center. Mean infarct size was as follows: center 1, 15%; center 2, 12%; center 3, 10%, center 4, 23% (all LV; p = 0.11 ). Mean left ventricular ejection fraction at discharge also demonstrated significant differences: center 1, 0.57; center 2, 0.47; center 3, 0.53; center 4, 0.47 (p = 0.002). The prevalence of Thrombolysis in Myocardial Infarction grade 3 flow after angioplasty significantly differed by center: center 1, 92%; center 2, 94%; center 3, 87%; center 4, 71 %; (p = 0.01). There was a low mortality rate for all four centers ranging from 0% to 6%. After adjustment for myocardium at risk, residual blood flow, and time to reperfusion, the primary outcome of the center where the angioplasty was performed was an independent determinant of both infarct size and left ventricular ejection fraction.
Conclusion:
The success of direct coronary angioplasty in reducing infarct size and preserving left ventricular function depends on the center performing the procedure. Direct measurement of the effectiveness of this reperfusion modality in community practice is required to assess the impact of this effect.