Trends in early and late mortality in patients undergoing coronary catheterization for myocardial infarction: implications on observation periods and risk factors to determine ICD candidacy

Predictors of Coronary Artery Disease Progression among High-risk Patients with Recurrent Symptoms

Background

Despite the availability of new potent medical therapies, the rate of progression of angiographic coronary artery disease (CAD) is not well described. The aim of this analysis is to describe the rate and predictors of progression of CAD among patients with recurrent symptoms.

Materials and Methods

We reviewed 259 patients (mean age 61 ± 11 years, 70% males) who underwent two coronary angiograms between 2008 and 2013. Progressive CAD was defined as obstructive CAD in a previously disease-free segment or new obstruction in a previously nonobstructive segment. Patients who had coronary artery bypass surgery between these two angiograms were excluded from the analysis. Multivariate logistic regression was used to determine the independent predictors of progression of CAD.

Results

The included cohort had a high prevalence of coronary risk factors; hypertension (71%), diabetes (69%), and dyslipidemia (75%). Despite adequate medical therapy, more than half of the patients (61%) had CAD progression. Using multivariate logistic regression, a drop in the left ventricular ejection fraction (LVEF) by more than 5% was the predictor of CAD progression (adjusted odds ratio 5.8, P = 0.042, 95% confidence interval 1.1-31.2).

Conclusion

Among high-risk patients with recurrent symptoms, the short-term rate of progression of CAD is high. A drop in LVEF >5% is a predictor of CAD progression. Further studies are needed to determine the prognostic value of CAD progression in the era of potent medical therapy.

The clinical challenge of preventing sudden cardiac death immediately after acute ST-elevation myocardial infarction

Unfortunately, of all patients experiencing acute myocardial infarction (MI), usually in the form of ST-elevation MI, 25-35% will die of sudden cardiac death (SCD) before receiving medical attention, most often from ventricular fibrillation. For patients who reach the hospital, prognosis is considerably better and has improved over the years. Reperfusion therapy, best attained with primary percutaneous coronary intervention compared to thrombolysis, has made a big difference in reducing the risk of SCD early and late after ST-elevation MI. In-hospital SCD due to ventricular tachyarrhythmias is manageable, with either preventive measures or drugs or electrical cardioversion. There is general agreement for secondary prevention of SCD post-MI with implantation of a cardioverter defibrillator (ICD) when malignant ventricular arrhythmias occur late (>48 h) after an MI, and are not due to reversible or correctable causes. The major challenge remains that of primary prevention, that is, how to prevent SCD during the first 1-3 months after ST-elevation MI for patients who have low left ventricular ejection fraction and are not candidates for an ICD according to current guidelines, due to the results of two studies, which did not show any benefits of early (<40 days after an MI) ICD implantation. Two recent documents may provide direction as to how to bridge the gap for this early post-MI period. Both recommend an electrophysiology study to guide implantation of an ICD, at least for those developing syncope or non-sustained ventricular tachycardia, who have an inducible sustained ventricular tachycardia at the electrophysiology study. An ICD is also recommended for patients with indication for a permanent pacemaker due to bradyarrhythmias, who also meet primary prevention criteria for SCD.