[Invasive revascularization strategy in non-ST-segment acute coronary syndromes. The debate continues]

[Relationship between short-term exposure to atmospheric sulfur dioxide and obstructive lesions in acute coronary syndrome]

BACKGROUND AND OBJECTIVES

Urban air pollutants are composed of a heterogeneous mixture of substances in gas and aerosol states. The aim of this study was to compare the effects caused by exposure to contaminants in the gas phase and atmospheric particles in ambient air in patients hospitalized for acute coronary syndrome (ACS) regarding the presence or absence of significant obstructive lesions (SOL) in epicardial coronary arteries.

PATIENTS AND METHODS

Prospectively analyzed a total of 2,110 patients with a diagnosis of ACS. We determined the mean concentrations of contaminants in the gas phase and atmospheric particles from the day before until 7 days prior to admission (1 to 7 days lag time). We divided the study population into those with presence or absence of SOL.

RESULTS

Of the 2,110 patients with ACS, 1,892 presented SOL and 218 without SOL. When comparing the concentrations of contaminants in the gas phase, we observed that the sulfur dioxide in patients with SOL had a trend toward higher values (10.93 ± 8.33 versus 9.31 ± 6.77 μg/m(3); P = .004). Multivariate analysis shows that for every 10 μg/m(3) increase of sulfur dioxide, there is an increase in the risk of hospitalization for ACS with SOL a 41% (odds ratio 1.41; 95% confidence interval 1.039-1.931; P = .028).

CONCLUSIONS

In our study population, exposure to high concentrations of sulfur dioxide is a precipitating factor for admission of patients with ACS and SOL.

Differential prognostic effect of revascularization according to a simple comorbidity index in high-risk non-ST-segment elevation acute coronary syndrome

BACKGROUND

Data on the effect of revascularization on outcome in patients with high-risk non-ST-segment elevation acute coronary syndrome (NSTEACS) and significant comorbidities are scarce. Recently, a simple comorbidity index (SCI) including 5 comorbidities (renal failure, dementia, peripheral artery disease, heart failure, and prior myocardial infarction [MI]) has shown to be a useful tool for risk stratification. Nevertheless, therapeutic implications have not been derived.

HYPOTHESIS

We sought to evaluate the prognostic effect attributable to revascularization in NSTEACS according the SCI score.

METHODS

We included 1017 consecutive patients with NSTEACS. The effect of revascularization on a combined end point of all-cause mortality or nonfatal MI was evaluated by Cox regression according to SCI categories.

RESULTS

A total of 560 (55.1%), 236 (23.2%), and 221 (21.7%) patients showed 0, 1, and ≥2 points according to the SCI, respectively. Coronary angiography was performed in 725 patients (71.5%), and 450 patients (44.3%) underwent revascularization. During a median follow-up of 16 months (interquartile range, 12-36 months), 305 (30%) patients experienced the combined end point (202 deaths [19.9%] and 170 MIs [16.7%]). In multivariate analysis, a differential prognostic effect of revascularization was observed comparing SCI ≥2 vs 0 (P for interaction = 0.008). Thus, revascularization was associated with a greater prognostic benefit in patients with SCI ≥2 (hazard ratio [HR]: 0.51, 95% confidence interval [CI]: 0.29-0.89), P = 0.018), whereas no significant benefit was observed in those with 0 and 1 point (HR: 1.31, 95% CI: 0.88-1.94, P = 0.171 and HR: 1.11, 95% CI: 0.70-1.76, P = 0.651, respectively).

CONCLUSIONS

In NSTEACS, the SCI score appears to be a useful tool for identifying a subset of patients with a significant long-term death/MI risk reduction attributable to revascularization.

Effect of invasive treatment on prognosis in non-ST-segment elevation acute coronary syndrome with or without systolic dysfunction

INTRODUCTION AND OBJECTIVES

Few data are available on the use of invasive treatment in patients with non-ST-segment elevation acute coronary syndrome (NSTEACS) and systolic dysfunction. The aim of this study was to determine the effect of invasive treatment on the prognosis of patients with NSTEACS, with or without systolic dysfunction.

METHODS

The study included 972 consecutive patients admitted for NSTEACS (i.e. ST-segment depression or an elevated troponin-I level). Systolic dysfunction was defined as an ejection fraction <50% on transthoracic echocardiography. The primary long-term endpoint was death or myocardial infarction. The effect of invasive treatment on prognosis was evaluated by Cox regression analysis.

RESULTS

Overall, 23.4% of patients had systolic dysfunction, and 303 (31.2%) reached the primary endpoint, which was more frequent in those with systolic dysfunction (49.8% vs. 25.5%; P< .001). Usage of coronary angiography and revascularization procedures were similar in patients with systolic dysfunction and those with an ejection fraction >/=50% (59% vs. 63.4%; P=.239; and 38.3% vs. 38.8%; P=.9; respectively). Detailed adjusted multivariate analysis, including the use of a propensity score, demonstrated that coronary angiography had a differential effect on prognosis depending on the presence or absence of systolic dysfunction (interaction, P=.01). Catheterization was clearly beneficial in patients with systolic dysfunction (hazard ratio [HR]=0.47; 95% confidence interval [CI], 0.3-0.75; P=.001) but not in those with an ejection fraction >/=50% (HR=0.9; 95% CI, 0.63-1.29; P=.567).

CONCLUSIONS

The presence of systolic dysfunction identifies those patients with NSTEACS who will benefit most from invasive treatment.