Role of infarct size in explaining the higher mortality in older patients with acute myocardial infarction

Evaluation of the influence of age and gender on the relationships between infarct size, infarct severity, and left ventricular ejection fraction in patients successfully treated with primary percutaneous coronary intervention

BACKGROUND

Female sex and advanced age have adverse prognostic meaning in acute myocardial infarction. Whether gender and/or age influence the relationship between infarct size, infarct severity, and left ventricular ejection fraction (LVEF) is unclear.

METHODS

We examined 460 patients (359 men) with acute myocardial infarction submitted to successful primary percutaneous coronary intervention. Infarct size, infarct severity, and LVEF were evaluated with perfusion gated SPECT at one month of index infarction.

RESULTS

There were no significant correlations between age and infarct size or infarct severity, and between age and LVEF. Moreover, elderly age (>or=75 years) did not influence the relationship between LVEF and infarct size or infarct severity. Conversely, there was a significant gender-related difference in the relationship between LVEF and infarct size (F = 20.5, P < .00001), and between LVEF and infarct severity (F = 8.6, P < .005). In practice, there was a steeper decrease in LVEF in case of moderate to large infarct size in women than in men.

CONCLUSION

With increasing infarct size, LVEF decreases more sharply in women than in men. Conversely, age does not influence the relationship between infarct dimensions and LVEF.

Early positive biomarker in relation to myocardial necrosis and impaired fatty acid metabolism in patients presenting with acute chest pain at an emergency room

BACKGROUND

Measurement of circulating biomarkers has enabled early diagnosis and risk assessment of acute coronary syndrome. This study sought diagnostic values of the first single-point data of biomarkers obtained soon after patient arrival by comparing with scintigraphically quantified myocardial injury in patients presenting with acute chest pain at an emergency room.

METHODS AND RESULTS

Serial blood samples were taken soon after arrival in an emergency department in 74 patients with suspected acute coronary syndrome to quantify blood levels of troponin-T (TnT), heart-type fatty acid-binding protein (H-FABP), myocardial-bound creatine kinase (CK-MB), and myoglobin. Myocardial perfusion and metabolic defects were scintigraphically quantified. The first single-point data had high positive predictive values for detecting the defects (80-100%) but low negative predictive values (15-41%). CK-MB and TnT had higher specificities (73-100%) but significantly lower positive rates (22-27%) than the others (61-68%), resulting in greater sensitivities of H-FABP and myoglobin (75-80%) than those of CK-MB and TnT (29-35%). Among biomarkers, TnT peak concentrations most closely correlated with scintigraphic abnormalities.

CONCLUSION

H-FABP can contribute to early detection of myocardial injury and TnT is most likely to correlate with injured myocardial mass. The differential features of biomarkers are complementary in patients with acute chest pain presenting at an emergency room.

Impact of ST-segment resolution after primary angioplasty on outcomes after myocardial infarction in elderly patients: an analysis from the CADILLAC trial

BACKGROUND

Age is a strong independent predictor of outcomes after primary percutaneous coronary intervention (PCI) for acute myocardial infarction (AMI). Whether lower rates of reperfusion success contribute to the poor prognosis in elderly patients is unknown.

METHODS

A formal ST-segment analysis substudy was performed in 695 patients undergoing primary PCI for AMI in the Controlled Abciximab and Device Investigation to Lower Late Angioplasty Complications (CADILLAC) trial. Reperfusion success (determined by the magnitude of ST-segment elevation resolution [STR] after PCI) was evaluated in 4 age groups: <50 years (n = 163), >or=50 to <60 years (n = 187), >or=60 to <70 years (n = 194), and >or=70 years (n = 151).

RESULTS

There were no differences in the age groups for angiographic procedural success (>91% in all, P =.6), postprocedural Thrombolysis in Myocardial Infarction grade 3 flow (>94%, P =.8), and the proportions of patients with complete, partial, or absent STR (P >.8). However, rates of 30-day mortality (0.6%, 1.1%, 3.6%, 6.0%, respectively) and major adverse cardiac events (MACE; 2.5%, 4.8%, 6.2% 9.3%, respectively) increased with age. Rates of mortality and MACE were also inversely related to the magnitude of STR. Absent STR (hazard ratio, 3.00; 95% CI, 1.37-6.58; P =.006) and age (hazard ratio, 1.34; 95% CI, 1.01-1.77; P =.04) were independent predictors of 30-day MACE by using multivariable modeling.

CONCLUSIONS

Lack of effective myocardial reperfusion is not a contributory mechanism responsible for the high morbidity and mortality rates observed in elderly patients. Nevertheless, advanced age and absent STR are both independent predictors of adverse outcomes after primary PCI, emphasizing the importance of successful reperfusion in the elderly population.