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Post-STEMI Remodeling and Outcome
Study Questions:
What is the impact of post-infarct left ventricular (LV) remodeling on outcomes in the current era of primary percutaneous coronary intervention (PCI) and optimal medical therapy?
Methods:
Clinical, angiographic, and echocardiographic data were reviewed for patients with ST-segment elevation myocardial infarction (STEMI) who have been collected in an ongoing registry at a single Dutch academic hospital since 2004. All patients were treated according to a standardized institutional protocol, including primary PCI within 90 minutes, comprehensive baseline echocardiogram within 48 hours of admission, and follow-up studies at 3, 6, and 12 months. LV remodeling was defined as an increase in the LV end-diastolic volume (LVEDV) of ≥20% as compared to baseline. The study group was divided into “remodelers” and “non-remodelers” and the LV remodeling group was further classified as early, mid, and late based on the timing of echo changes (present at 3, 6, or 12 months post-STEMI, respectively). Subgroup analysis was performed according to baseline LV ejection fraction (EF) <40%, EF 40-49%, and EF >50%.
Results:
A total of 1,995 patients were analyzed (mean age 60 years ± 12 years, 77% male), of whom 953 (48%) were remodelers (63% early, 23% midterm, and 13% late). LV remodelers had a slightly higher incidence of hypertension (p = 0.05) and diabetes (p = 0.026) at baseline as well as a higher peak troponin T of 4.4 µg/L (interquartile range [IQR], 1.0-9.0 vs. 2.9 µg/L [IQR, 1.2-6.1]; p < 0.001) and higher wall motion score index. Remodelers also had a smaller baseline LVEDV and lower LVEF. In LV remodelers, the mean LVEDV increased from 94 ± 28 ml at baseline to 125 ± 42 ml at 3 months, 123 ± 41 ml at 6 months, and 118 ± 41 ml at 12 months. Non-remodelers had a decrease in LVEDV from 117 ± 34 at baseline to 102 ± 33 at 12 months (p < 0.001). The mean LVEF overall was 47 ± 9% at baseline, which increased up to 53 ± 10% at 12 months. There were no significant differences in LVEF changes between the remodelers and non-remodelers.
Median follow-up was 94 (IQR, 69-119) months, during which 11% of patients died. All-cause mortality was 5%, 11%, and 19% at 40, 80, and 120 months, respectively, in LV remodelers vs. 4%, 9%, and 16% in non-remodelers (p = 0.144). No significant difference in mortality was found between remodelers and non-remodelers even across subgroups with differing baseline LVEF.
In contrast, rates of heart failure hospitalizations were higher for LV remodelers (6%, 7%, and 9% at 40, 80, and 120 months, respectively) than non-remodelers (2%, 3%, and 4%) (p < 0.001). Unlike mortality, this outcome varied across LVEF subgroups – LV remodelers with EF of <40% or EF 40-49% had more heart failure admissions than non-remodelers in these subgroups (p = 0.004), while there were no significant differences between remodelers and non-remodelers with baseline LVEF >50% (p = 0.471).
Conclusions:
The authors concluded that 48% of STEMI patients treated with primary PCI and standard pharmacotherapy at a Dutch academic hospital, from 2004 to present, demonstrated LV remodeling in the first year post-infarct. Remodelers had no significant increase in mortality versus non-remodelers, irrespective of baseline LVEF, but those with LVEF <50% did have a higher rate of heart failure admission than non-remodelers with similar LV systolic function.
Perspective:
Clinical trial data from the thrombolytic era demonstrated that post-infarct LV remodeling, at that time defined as increases in LV end-diastolic area on TTE, was common and associated with adverse cardiac events, such as heart failure, functional mitral regurgitation, ventricular arrhythmias, and mortality (see Pfeffer MA, et al., N Engl J Med 1992;327:669-77 and St John Sutton M, et al., Circulation 1997;96:3294-9). These data are of questionable relevance given the widespread implementation of primary PCI and substantial change in post-infarct pharmacotherapy.
The current study sought to re-evaluate the effect of LV remodeling on long-term outcomes in STEMI patients in the context of current practices. Indeed, the investigators found a high incidence of LV remodeling, predominantly in the first 3 months following infarct, but no correlation between remodeling and mortality, even in patients with reduced baseline LVEF. Limitations include single-center, retrospective design, the fact that echo data were not analyzed at a core laboratory, and most significantly, measurement of all-cause mortality with no specific differentiation of cardiac versus noncardiac cause. Implications for future research and opportunities for possible intervention may lie in the study’s finding that LV remodelers have a higher incidence of heart failure admissions. It will be interesting to see if increased surveillance and use of newer medications, such as angiotensin receptor neprilysin inhibitors, could reduce hospitalization rates in the future.
Clinical Topics: Heart Failure and Cardiomyopathies, Invasive Cardiovascular Angiography and Intervention, Noninvasive Imaging, Prevention, Acute Heart Failure, Interventions and Imaging, Angiography, Echocardiography/Ultrasound, Nuclear Imaging, Hypertension
Keywords: Angiography, Diabetes Mellitus, Echocardiography, Heart Failure, Hypertension, Myocardial Infarction, Percutaneous Coronary Intervention, Stroke Volume, Systole, Troponin T, Ventricular Remodeling
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