Impact of age at the time of the first ST-elevation myocardial infarction on 10-year outcomes. A sub-analysis from the EXAMINATION EXTEND trial

Background

The aim of this post-hoc sub analysis of the EXAMINATION-EXTEND study was to analyze 10-year outcomes according to the age of the patient at the time of the first STEMI.

Methods

Out of 1498 STEMI patients included in the EXAMINATION-EXTEND study, those with a previous history of atherosclerotic cardiovascular disease (coronary ischemic event, ischemic stroke, or previous coronary revascularization) were excluded for this analysis. The remaining 1375 patients were divided into three age groups: <55, 55–65 and >65 years. The primary endpoint was 10-year patient oriented composite endpoint (POCE) of all-cause death, any myocardial infarction (MI), or any revascularization. Secondary endpoints included the individual components of the primary endpoint, cardiac death, target vessel myocardial infarction (TVMI), target lesion revascularization (TLR), and stent thrombosis. The association between age and endpoints was adjusted for baseline confounders.

Results

At 10-year follow-up, patients <55 years (Adjusted hazard ratio [HR]: 0.42, 95% CI: 0.33–0.53, p=0.001), and 55–65 years (Adjusted HR: 0.44, 95% IC: 0.35–0.56, p=0.001) showed lower risk of POCE compared with those >65 years, led by a lower incidence of all-cause death (<55: 5.8% vs. 55–65: 11.3% vs. >65 years: 40.67%, p=0.001). Cardiac death was more prevalent in the older group (<55: 3.5% vs. 55–65: 5.5% vs. >65 years: 21.3%, p=0.001). There were not significant differences in the incidence of TVMI, TLR and stent thrombosis among the different age groups. In the landmark analyses, between 5 and 10-year follow-up, young patients exhibited higher incidence of any revascularization (<55: 7.4% vs. 55–65: 4.9% vs. >65 years: 1.7%, p=0.001) and a trend towards a higher incidence of any MI (<55: 5.2% vs. 55–65: 3.6% vs. >65 years: 1.5%, p=0.064). No differences were found in any other endpoints.

Conclusions

In patients with a first STEMI, advanced age was associated with high rates of POCE at 10-year follow-up, in particular, due to all-cause and cardiac death. Conversely, patients who presented at younger age exhibited a high risk of revascularization at long-term follow-up.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Abbott Vascular

Microvascular dysfunction and absolute coronary blood flow after percutaneous coronary intervention of a chronic total occlusion

 

The development of a coronary chronic total occlusion (CTO) causes changes in the distal epicardial vascular bed and in the microvasculature tributary of the occluded vessel. Studies with positron emission tomography showed an increase in myocardial blood flow and coronary flow reserve (CFR) after percutaneous coronary intervention (PCI) of a CTO (1). These changes are not immediate after PCI, since they usually involve a process of weeks-months (2).

The FLOW-CTO study aims to evaluate the evolution of microvascular resistance and absolute coronary blood flow (ABF) after PCI of a CTO.

The study consecutively included patients in 4 national centers in Spain. In these patients, a coronary physiology study was performed, immediately after PCI and at 6 months follow-up. Fractional flow reserve (FRR), CFR and index of microcirculatory resistance (IMR) were determined. ABF and microvascular resistances were determined by continuous thermodilution during maximal hyperemia induced by serum infusion (3). Coronary microvascular dysfunction (MVD) was defined as an IMR ≥25 and/or an CFR <2.0, in the presence of an FFR >0.80. We present data from the baseline study immediately after PCI of a CTO in the first 49 patients.

Most patients were male (90%), with a median age of 62 years-old [IQR 56–69]. The prevalence of hypertension, dyslipidemia and diabetes were 71, 67 and 41%, respectively. The median left ventricular ejection fraction was 55% [IQR 45–60]. Eighty-six percent of the patients had exertional angina and 14% had history of congestive heart failure.

The most frequently involved vessel was the right coronary artery (55%). The most used technique was antegrade guidewire escalation (74%). The median length of the devices implanted was 59±25 mm. The mean percentage of residual stenosis was 8±4%.

Despite the good angiographic result, 20% of the lesions had an FFR value ≤0.80. Of those patients with a non-significant FFR value (>0.80), 54% had signs of MVD. Those patients with an elevated IMR (≥25) showed a non-significant trend towards a lower ABF (143±79 vs. 192±59 mL/min; p=0.1043), with significantly higher microvascular resistance (694±206 vs. 471±166 mmHg/(l/min); p=0.0328). Those patients with a reduced CFR (<2.0) had lower ABF (166±57 vs. 207±64 ml/min; p=0.0460) and a non-significant trend towards a higher microvascular resistance (535±240 vs. 466±195 mmHg/(l/min); p=0.3419). Diabetes mellitus was identified as a predictor of an elevated IMR (OR 6.3, 95% CI 1.1–13; p=0.046) or reduced CFR (OR 5.7, 95% CI 1.4–22, p=0.013).

In our study, more than half of the patients presented signs of MVD immediately after PCI of a CTO. Despite an optimal angiographic result, in a fifth of the cases we found a significant alteration of the parameters that evaluate the epicardial circulation. Diabetes mellitus was found as a predictor of MVD after PCI of a CTO.

Funding Acknowledgement

Type of funding sources: None.

Similar degree of intimal coverage and apposition among drug-eluting stents with persistent, absorbable or without polymer at 1 and 6 months after implantation

Background

Despite technological advances in drug-eluting stents (DES) design, delayed vascular healing is still a problem, triggered by the polymers among others. This may induce restenosis and thrombosis. The development of biodegradable polymers and DES without polymer is thought to improve the vascular response and enhance earlier neointimal healing. Optical coherence tomography (OCT) is the best intracoronary imaging tool to evaluate endothelial coverage after stent implantation.

Purpose

We aimed to quantitatively assess the differences on intimal coverage between biodegradable-polymer, durable-polymer and without-polymer DES at 1 and 6-month follow-up OCT.

Methods

A total of 94 patients with de novo coronary lesions were treated with DES: 26% were treated with Biolimus A9 (BA9) stent without polymer, 30% were treated with Everolimus DES with biodegradable polymer (EESb) and 44% with Everolimus DES with persistent polymer (EESp). OCT analysis was performed blindly at an independent Core Lab at three stages: implantation, after one month and after six months.

The primary endpoint was to compare neointimal coverage and apposition of these three different types of DES with OCT at one and six months after implantation.

Results

A total of 16034 struts were analysed (24% BA9, 29% EESb and 47% EESp). No significant differences were found among the groups regarding baseline clinical characteristics. When studying the strut coverage, it is remarkable the relatively low percentage of early neointimal coverage with no significant differences among stents one month after implantation (84–87%). After six months, there was better coverage in the three stent groups compared with one month (p<0.001). The stents without polymer had better neointimal coverage at six months compared with the stents with persistent polymer (99% vs 92%, p=0.0002). No significant differences were found in the strut apposition after one or six months among the three stent types. However, the rate of apposition was higher after six months compared with one month in all stent groups (p=0,001). No significant differences were found in the neointimal hyperplasia at one month among the three stent groups. At six months there was a higher hyperplasia in the stent without polymer compared to the stent with persistent polymer (164μm vs 92μm, p=0,003). The degree of hyperplasia after six months was higher compared to one month in all groups (p=0,001).

Conclusions

The new-generation DES with biodegradable-polymer or without polymer showed relatively poor early neointimal coverage and similar to the last generation durable-polymer EES. According to these results, DAPT may not be shortened in any of the three DES types studied.

Funding Acknowledgement

Type of funding source: None