Clinical and angiographic characteristics of patients with spontaneous reperfusion in ST-segment elevation myocardial infarction

Angiographic characteristics of coronary artery disease in patients undergoing diagnostic coronary angiography at a tertiary hospital in Tanzania

BACKGROUND

Coronary artery disease (CAD) is an important cause of global burden of disease. There is a paucity of data on the burden and risk factors for CAD in sub-Saharan Africa (SSA), despite the rising trends in the shared risk factors across regions. The recent introduction of cardiac catheterization laboratory services in SSA could shed light on the burden of CAD in the region. We aimed to assess the angiographic characteristics among patients undergoing diagnostic coronary angiography (CAG) at a single tertiary care hospital in Tanzania.

METHODS

This study was a retrospective chart review. A total of 728 patients  ≥ 18 years of age who underwent CAG from January 2020 to December 2022 were recruited into the study. Basic demographic variables, risk factors and clinical characteristics including CAG findings were obtained from the registry. In addition, CAG images were retrieved for assessment of angiographic features. The luminal vessel stenosis was assessed based on eyeballing and the degree of obstruction was agreed by two independent and experienced cardiologists. The coronary stenosis of ≥ 50% was considered significant for obstructive CAD. The study was approved by the local ethics committee.

RESULTS

Of patients who were recruited into the study, 384 (52.23%) were female. The study participants had a mean age of 59.46 ± 10.83 standard deviation (SD) and mean body mass index (BMI) of 31.18 kg/m2. The prevalence of CAD of any degree was estimated at 24.43% (34.18% in male, 15.50% in female), while that of obstructive CAD was 18.27%. Forty six percent of those with obstructive CAD had multiple vessel disease (MVD). Nearly 77% of patients were found to have ≥ 50-70% luminal stenosis and while those with ≥ 70% luminal coronary artery stenosis constituted 56.65%. Right coronary artery (RCA) was the most commonly affected vessel, accounting for 36.84% when any vessel disease or 56% when single vessel disease were considered. Being 65 years or older and comorbidity with type 2 diabetes (T2D) were independent risk factors for developing CAD.

CONCLUSION

There is a high prevalence of obstructive CAD among patients undergoing diagnostic CAG in Tanzania, with male gender preponderance and increasingly higher in older age, often with severe disease. A large, prospective study is needed to provide epidemiological and clinical data for developing a locally-relevant cardio-preventive strategy for CAD intervention in Tanzania.

​Circulating Cytokines in Myocardial Infarction Are Associated With Coronary Blood Flow

Background

The level of systemic inflammation correlates with the severity of the clinical course of acute myocardial infarction (AMI). It has been shown that circulating cytokines and endothelial dysfunction play an important role in the process of clot formation. The aim of our study was to assess the concentration of various circulating cytokines, endothelial function and blood clotting in AMI patients depending on the blood flow through the infarction-related artery (IRA).

Methods

We included 75 patients with AMI. 58 presented with ST-elevation myocardial infarction (STEMI) and 17 had non-ST-elevation myocardial infarction (non-STEMI). A flow-mediated dilation test (FMD test), thrombodynamics and rotational thromboelastometry as well as assessment of 14 serum cytokines using xMAP technology were performed.

Findings

Non-STEMI-patients were characterized by higher levels of MDC, MIP-1β, TNF-α. Moreover, we observed that patients with impaired blood flow through the IRA (TIMI flow 0-1) had higher average and initial clot growth rates, earlier onset of spontaneous clots, C-reactive protein (CRP) and IL-10 compared to patients with preserved blood flow through the IRA (TIMI flow 2-3). Patients with TIMI 2-3 blood flow had higher level of IP-10. IL-10 correlated with CRP and pro-inflammatory cytokines levels, initial clot growth rate and clot lysis time in TIMI 0-1 patients. All these differences were statistically significant.

Interpretation

We demonstrated that concentrations of the inflammatory cytokines correlate not only with the form of myocardial infarction (STEMI or non-STEMI), but also with the blood flow through the infarct-related artery. Inflammatory response, functional state of endothelium, and clot formation are closely linked with each other. A combination of these parameters affects the patency of the infarct-related artery.

Plaque characteristics in patients with ST-segment elevation myocardial infarction and early spontaneous reperfusion

BACKGROUND

Early spontaneous reperfusion (ESR) is not an uncommon phenomenon in clinical settings.

AIMS

The aim of this study was to detect potential mechanisms of ESR in patients with STEMI.

METHODS

This prospective study enrolled a total of 241 consecutive patients with STEMI undergoing optical coherence tomography (OCT) from July 2016 to August 2019. Forty-five patients (18.7%) met angiographic ESR criteria (TIMI 3 flow on the initial angiogram). Among those without ESR (TIMI 0 flow on initial angiogram), 45 patients were assigned to the control group according to propensity score matching with the ESR group.

RESULTS

Although the baseline characteristics of the groups were comparable, non-ruptured plaque (62.2% vs 35.6%) predominated and plaque rupture (37.8% vs 64.4%) was less common in the ESR group (p=0.011). Red thrombus (44.4% vs 77.8%) was also less common in the ESR group (p=0.001). Lastly, compared to the control group, the ESR group underwent fewer emergent stent placements (68.9% vs 91.1%, p=0.008).

CONCLUSIONS

Relief of coronary occlusion induced by a non-ruptured plaque may contribute to ESR in patients with STEMI.