Prognostic differences between routine invasive and conservative strategies for the management of high-risk, non-ST segment acute coronary syndromes: Experience from two consecutive periods in a single center

Long-term prognosis of patients with acute non-ST-segment elevation myocardial infarction undergoing different treatment strategies

Background:

In cardiology, it is controversial whether different therapy strategies influence prognosis after acute coronary syndrome. We examined and compared the long-term outcomes of invasive and conservative strategies in patients with non-ST-segment elevation myocardial infarction (NSTEMI) and characterized the patients selected for an invasive approach.

Methods:

A total of 976 patients with acute NSTEMI were collected from December 2006 to October 2012 in the First Affiliated Hospital of Dalian Medical University Hospital. They are divided into conservative strategy (586 patients) and invasive strategy (390 patients) group. Unified follow-up questionnaire was performed by telephone contact (cut-off date was November, 2013). The long-term clinical events were analyzed and related to the different treatment strategies.

Results:

The median follow-up time was 29 months. Mortality was 28.7% (n = 168) in the conservative group and 2.1% (n = 8) in the invasive management at long-term clinical follow-up. The secondary endpoint (the composite endpoint) was 59.0% (n = 346) in the conservative group and 30.3% (n = 118) in the invasive management. Multivariate analysis showed that patients in the conservative group had higher all-cause mortality rates than those who had the invasive management (adjusted risk ratio [RR] = 7.795; 95% confidence interval [CI]: 3.796–16.006, P < 0.001), and the similar result was also seen in the secondary endpoint (adjusted RR = 2.102; 95% CI: 1.694–2.610, P < 0.001). In the subgroup analysis according to each Thrombolysis in Myocardial Infarction risk score (TRS), log-rank analysis showed lower mortality and secondary endpoint rates in the invasive group with the intermediate and high-risk patients (TRS 3–7).

Conclusions:

An invasive strategy could improve long-term outcomes for NSTEMI patients, especially for intermediate and high-risk ones (TRS 3–7).

Outcomes in patients with non-ST-elevation acute coronary syndrome randomly assigned to invasive versus conservative treatment strategies: a meta-analysis

OBJECTIVE

The goal of the present study was to compare the prognoses of patients with non-ST-elevation acute coronary syndromes who were treated with invasive or conservative treatment strategies.

METHODS

We performed a meta-analysis of studies of patients with non-ST-elevation acute coronary syndromes to assess the benefits of an invasive strategy vs. a conservative strategy for short- and long-term survival. We searched PubMed for studies published from 1990 to November 2012 that investigated the effects of an invasive vs. conservative strategy in patients with non-ST-elevation acute coronary syndromes. The following search terms were used: "non-ST-elevation myocardial infarction", "unstable angina", "acute coronary syndromes", "invasive strategy", and "conservative strategy". The primary endpoints were all-cause mortality at 30 days and 1 year.

RESULTS

Seven published studies were included in the present meta-analysis. The pooled analyses show that an invasive strategy decreased the risk of death (risk ratio [0.839] [95% confidence interval {0.648-1.086}; I 2, 86.46%] compared to a conservative strategy over a 30-day-period. Furthermore, invasive treatment also decreased patient mortality (risk ratio [0.276] [95% confidence interval {0.259-0.294}; I 2, 94.58%]) compared to a conservative strategy for one year.

CONCLUSION

In non-ST-elevation acute coronary syndromes, an invasive strategy is comparable to a conservative strategy for decreasing short- and long-term mortality rates.

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.

Therapeutic implications of low lymphocyte count in non-ST segment elevation acute coronary syndromes

BACKGROUND

Low lymphocyte count (LLC), a surrogate for inflammation, has emerged as a potential risk factor for cardiovascular outcomes, especially new ischemic events. To identify patients with non-ST segment elevation acute coronary syndromes (NSTEACS) who benefit from an invasive revascularization strategy remains a challenge. We sought to determine if patients with high-risk NSTEACS who exhibited LLC have a greater reduction in long-term post-discharge myocardial infarction (MI) when managed under a revascularization invasive strategy (RIS) as compared with conservative strategy (CS).

METHODS

Nine hundred seventy two consecutive patients with high-risk NSTEACS were treated under two revascularization strategies (RS): 1) CS, from January 2001 to October 2002 (345 patients; 35.5%) and 2) RIS, from November 2002 to May 2005 (627 patients; 64.5%). LLC was defined as lymphocytes count < or =1200 cells/ml (1 vs. 2-4 quartiles). The association between the type of RS and MI was stratified by lymphocyte count status and assessed by Cox regression adapted for competing events.

RESULTS

At 3-year follow-up, 145 deaths (14.9%), 135 MI (13.9%) and 76 revascularization procedures (7.8%) were registered. In a multivariable setting, LLC patients exhibited a greater MI risk reduction when managed under RIS (HR: 0.40; 95% CI=0.22-0.72, p=0.003). Conversely, when LLC was not present, no difference in the rate of MI was detected between the two RS.

CONCLUSIONS

LLC identifies a subgroup of patients with greater reduction in the risk of postdischarge MI when a RIS is applied.

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

Revascularization strategy in the setting of non-ST-segment acute coronary syndromes remains a controversy. Evidence obtained from clinical trials, generally performed in selected patients, reveals heterogeneous and insufficient results when a routine invasive revascularization strategy and a conservative one are compared. The conflicting results among trials are due to differences in: a) baseline characteristics; b) methodology and protocols applied and; c) objectives and outcomes definitions. Although present guidelines recommend that a routine invasive strategy should be used in high risk non-ST-segment elevation acute coronary syndromes, there is no consistent evidence that supports this approach. In order to reach definitive conclusions, further randomized studies should: a) expand inclusion criteria to highest risk populations and; b) standardize the methodology, objectives and outcome definitions.