Meta-analysis of mental stress-induced myocardial ischemia and subsequent cardiac events in patients with coronary artery disease

Abstract

Mental stress-induced myocardial ischemia (MSIMI) has been associated with adverse prognosis in patients with coronary artery disease (CAD), but whether this is a uniform finding across different studies has not been described. We conducted a systematic review and meta-analysis of prospective studies examining the association between MSIMI and adverse outcome events in patients with stable CAD. We searched PubMed, EMBASE, Web of Science, and PsycINFO databases for English language prospective studies of patients with CAD who underwent standardized mental stress testing to determine presence of MSIMI and were followed up for subsequent cardiac events or total mortality. Our outcomes of interest were CAD recurrence, CAD mortality, or total mortality. A summary effect estimate was derived using a fixed-effects meta-analysis model. Only 5 studies, each with a sample size of <200 patients and fewer than 50 outcome events, met the inclusion criteria. The pooled samples comprised 555 patients with CAD (85% male) and 117 events with a range of follow-up from 35 days to 8.8 years. Pooled analysis showed that MSIMI was associated with a twofold increased risk of a combined end point of cardiac events or total mortality (relative risk 2.24, 95% confidence interval 1.59 to 3.15). No heterogeneity was detected among the studies (Q=0.39, I2=0.0%, p=0.98). In conclusion, although few selected studies have examined the association between MSIMI and adverse events in patients with CAD, all existing investigations point to approximately a doubling of risk. Whether this increased risk is generalizable to the CAD population at large and varies in patient subgroups warrant further investigation.

Figure 1

Flowchart showing selection of study reports for the meta-analysis.

Figure 2

Forest plot of the 5 cohort studies included in the meta-analysis. Squares indicate risk ratio estimates for individual studies; square size is proportional to the weight of the corresponding study in the meta-analysis. Horizontal lines represent 95% confidence intervals. The diamond represent the pooled relative risk and 95% confidence interval. IV, Fixed stand for inverse variance method, fixed effects model.

Figure 3

Funnel plot of the 5 cohort studies included in the meta-analysis. RR = relative risk; SE = standard error.