RESUMO
Despite impressive improvements in the care of patients with ST-segment elevation myocardial infarction, mortality remains high. Reperfusion is necessary for myocardial salvage, but the abrupt return of flow sets off a cascade of injurious processes that can lead to further necrosis. This has been termed myocardial ischemia-reperfusion injury and is the subject of this review. The pathologic and molecular bases for myocardial ischemia-reperfusion injury are increasingly understood and include injury from reactive oxygen species, inflammation, calcium overload, endothelial dysfunction, and impaired microvascular flow. A variety of pharmacologic strategies have been developed that have worked well in preclinical models and some have shown promise in the clinical setting. In addition, there are newer mechanical approaches including mechanical unloading of the heart prior to reperfusion that are in current clinical trials.
Assuntos
Traumatismo por Reperfusão Miocárdica , Humanos , Traumatismo por Reperfusão Miocárdica/fisiopatologia , Traumatismo por Reperfusão Miocárdica/etiologia , Infarto do Miocárdio/fisiopatologia , Reperfusão Miocárdica/métodos , Infarto do Miocárdio com Supradesnível do Segmento ST/fisiopatologia , Infarto do Miocárdio com Supradesnível do Segmento ST/terapiaRESUMO
BACKGROUND: Frailty associates with worse outcomes after transcatheter aortic valve replacement (TAVR). Sarcopenia underlies frailty, but the association between a comprehensive assessment of sarcopenia-muscle mass, strength, and performance-and outcomes after TAVR has not been examined. METHODS: From a multicenter prospective registry of patients with symptomatic severe aortic stenosis undergoing TAVR, 445 who had a preprocedure computed tomography and clinical assessment of frailty were included. Cross-sectional muscle (psoas and paraspinal) areas were measured on computed tomography and indexed to height. Gait speed and handgrip strength were obtained, and patients were dichotomized into fast versus slow; strong versus weak; and normal versus low muscle mass. As measures of body composition, cross-sectional fat (subcutaneous and visceral) was measured and indexed to height. RESULTS: The frequency of patients who were slow, weak, and had low muscle mass was 56%, 59%, and 42%, respectively. Among the 3 components of sarcopenia, only slower gait speed (muscle performance) was independently associated with increased post-TAVR mortality (adjusted hazard ratio, 1.12 per 0.1 m/s decrease [95% CI, 1.04-1.21]; P=0.004; adjusted hazard ratio, 1.38 per 1 SD decrease [95% CI, 1.11-1.72]; P=0.004). Meeting multiple sarcopenia criteria was not associated with higher mortality risk than fewer. Lower indexed visceral fat area (adjusted hazard ratio, 1.48 per 1 SD decrease [95% CI, 1.15-1.89]; P=0.002) was associated with mortality but indexed subcutaneous fat was not. Death occurred in 169 (38%) patients. CONCLUSIONS: Among patients with symptomatic severe aortic stenosis and comprehensive sarcopenia and body composition phenotyping, gait speed was the only sarcopenia measure associated with post-TAVR mortality. Lower visceral fat was also associated with increased risk pointing to an obesity paradox also observed in other patient populations. These findings reinforce the clinical utility of gait speed as a measure of risk and a potential target for adjunctive interventions alongside TAVR to optimize clinical outcomes.