Angiographic Outcomes in STEMI Patients: Evaluating Pre-dilatation and Thrombus Aspiration Effects

1. Introduction

STEMI (ST-elevation myocardial infarction) is the most widely occurring type of myocardial infarction that requires immediate medical attention. It is one of the main causes of mortality in patients with cardiovascular diseases.¹ STEMI is caused by stenosis that involves the plaque accumulated in the arteries that get ruptured leading to thrombosis formation.² The complete blockage in one or several coronary arteries leading to transmural myocardial ischemia causing myocardial infarction or necrosis.³

Over 3 million population experience STEMI every year with more than 4 million of the population showing STEMI pathology mostly observed in the countries that are developed.⁴ According to a study of 19,781 patients with coronary artery disease, the prevalence rate of STEMI was 23.3%.^5,6 A study reported among the Asian individuals, showed that the incidence rates observed ranged from 33 to 138 cases per 100,000 individuals annually.⁷

The occurrence of STEMI varies from different regions and populations and is impacted by various factors.⁴ Factors like age, where increased age could be a potential risk for an increase in the occurrence of STEMI, commonly experienced by patients over 65 years with conditions like diabetes, high blood pressure, and atherosclerotic disease.⁶ Coming to genders, Men are at higher risk of suffering from STEMI when compared with women. However, Women after menopause may be on the radar of developing STEMI, reducing the gender gap.⁸ Furthermore, factors like unhealthy eating habits, lack of physical activity, using tobacco products, and availability of medical services can also be a cause of the increased rate of STEMI cases.⁹

Over the years, there has been developed various treatment approaches to manage STEMI that have evolved substantially aiming at reducing myocardial infarction and improving the quality of life of the patients. Treatment approaches like Reperfusion therapy include primary Percutaneous Coronary Intervention (PCI) which involves mechanical removal of the thrombus, opening the blockage, and restoring the blood flow by placing a stent at the blocked coronary artery.¹⁰ Another method of reperfusion therapy includes Thrombolytic therapy where thrombolytic components like tissue plasminogen activator or reteplase, help to dissolve the blocked coronary artery thrombus and restore the blood flow.¹¹

Along with the standard treatment, adjunctive medical therapies like dual antiplatelet therapy, anticoagulation, Beta-blockers, Angiotensin-converting enzyme (ACE) Inhibitors, angiotensin receptor blockers (ARBs), and Statins are used to treat patients with STEMI by restoring the blood flow and improving the functionality of the arteries.⁹

Thrombus aspiration (TA) is used to remove the blood clot before the placement of the stent, hence reducing the mobilization of an embolus and improving the function of the arteries.¹² However, recent trials have claimed to have uncertainty about the advantages of TA and proposed an increased risk of stroke in patients with no reduction in mortality.^13,14 Whereas Autotransfusion involves gathering and infusing the patient’s blood again. This could reduce the requirement of performing allogenic transfusion as it carries a huge risk of infections, immune reactions, and diseases that are transmitted through transfusion.^15,16

In a study conducted with 286 number of STEMI patients, those patients undergoing Percutaneous Transluminal Coronary Angioplasty (PTCA) with TA showed better outcomes compared to conventional angioplasty. However, a larger analysis with 19,047 patients showed that routine TA during PCI did not reduce cardiovascular mortality or stroke rates. In high thrombus burden cases, TA lowered cardiovascular deaths but increased stroke risk, that suggested a need for refined strategies.¹²

Like mentioned previously PPCI emerging as the preferred therapy where available. However, achieving successful myocardial reperfusion remains challenging due to several obstacles. Among these, high thrombus burden is particularly noteworthy, affecting a substantial number of patients. During PPCI, procedures such as wire manipulation, balloon dilatation, and stent placement in culprit vessels with high thrombus burden can lead to distal embolization of thrombus fragments and atherosclerotic plaque debris. This process impairs myocardial perfusion, potentially resulting in poorer short- and long-term outcomes, including heart failure and mortality. The present study aims to address these challenges by assessing the angiographic outcomes of pre-dilatation and TA compared to conventional treatment without TA in patients undergoing PPCI for STEMI

2. Methods

3. Results

4. Discussion

In our study, we compared the outcomes of conventional PPCI with those of PPCI combined with TA in patients presenting with STEMI. The main findings highlighted several key differences between the two treatment approaches. In our study, we analysed the baseline characteristics and hemodynamic parameters of patients undergoing PPCI with pre-dilatation and thrombus aspiration (PD+TA) compared to those not receiving thrombus aspiration (NOTA). The mean age of participants in the PD+TA group was 60.2±11.5 years and NOTA group with a mean age of 61.6±11.8 years, indicating comparable age distribution between the two cohorts.

In a study by Elfekky et al.,¹⁷ the relationship between HTN and the use of TA in patients undergoing PPCI. The incidence of hypertension was almost identical between the who did not receive thrombus aspiration (50.0%) and of patients who did (50.7%). However, in our study we observed significant differences in blood pressure measurements between the two groups. Patients in the PD+TA group had significantly lower systolic blood pressure (SBP) (127.3±29.1 mmHg vs. 137.9±27.2 mmHg, p=0.021) and diastolic blood pressure (DBP) (79.16±17.3 mmHg vs. 84.4±15.2 mmHg, p=0.046) compared to those in the NOTA group

In the present study we compared the ejection fraction between the two groups, and found that at the one-month follow-up, the PD+TA group showed a significantly (p-value: 0.029) higher mean ejection fraction (52.29±8.80%) compared to the NOTA group (49.14±8.20%). ST-segment elevation was also significantly (p-value: 0.003) higher in the PD+TA group (6.22±3.06) compared to the NOTA group (4.90±2.26).

Additionally, ST-segment resolution was significantly (p-value: 0.027) greater in the PD+TA group (2.05±1.91) than in the NOTA group (1.41±1.60). A study conducted in Egypt showed that ST-segment resolution greater than 70% was achieved in 97.2% of the patients who underwent TA, compared to 86.8% in the patients who did not receive TA. The improved ST-segment resolution could be attributed to the mechanical removal of the thrombus, which may enhance the efficacy of PPCI by reducing the thrombotic burden and facilitating better perfusion of the distal coronary vasculature.

In our study, we observed that Thrombolysis in Myocardial Infarction (TIMI) flow and TMPG grades were similar across both treatment groups, indicating comparable immediate angiographic outcomes. However, the corrected TIMI frame count (CTFC), both before and after drug administration, showed significant improvement in the PD+TA group. Specifically, the post-drug CTFC was significantly lower in the PD+TA group (26.56±10.14) compared to the NOTA group (32.40±16.50), with a p-value of 0.004. Supporting our findings, Gao et al.¹⁸ reported that patients in the TA group demonstrated better TIMI flow grade classifications.

In our study, we found no significant differences in the distribution of myocardial infarction (MI) locations or the infarct-related vessels (LAD, RCA, LCx) between the groups. Similarly, the coronary artery disease (CAD) status, categorized as single, double, or triple vessel disease, was comparable across the groups. In contrast, the study by Kazazi et al.¹⁹ showed distinct findings. They reported that 33.2% of anterior wall MI patients and 19.6% of inferior wall MI patients had single vessel disease. Additionally, 72.0% of inferior wall MI patients had multi-vessel CAD, while this figure was 59.3% for anterior wall MI patients

In our study, we elaboaretly evaluated the TIMI 3 flow and TMPG 3 flow outcomes, both before and after drug administration, in two groups: These findings suggest that while TIMI 3 and TMPG 3 flow rates before and after drug administration were comparable between the NOTA and PD+TA groups, the PD+TA group showed more pronounced improvements in CTFC outcomes. The significant improvement in CTFC with and without drug administration in the PD+TA group indicates that pre-dilatation and thrombus aspiration may enhance coronary blood flow more effectively than conventional PCI alone.

Ejection fraction is a critical measure of cardiac function, and improvements in EF are associated with better clinical outcomes in patients with STEMI. The mean increase of 4.80±7.29 in the PD+TA group suggests that PD+TA may contribute to more effective myocardial salvage and recovery of left ventricular function. In contrast, the smaller mean increase of 1.55±4.91 in the NOTA group points to less pronounced improvements in cardiac function with conventional PPCI alone.

While the lack of statistical significance means we cannot definitively conclude that PD+TA is superior based on EF improvements alone, the trend observed in our study is consistent with other positive outcomes associated with TA, such as better ST segment regression and improved CTFC. These findings collectively suggest that PD+TA may offer enhanced benefits in the acute management of STEMI.

In the present study, there was no notable contrast observed between patients who received pre-dilatation and those who did not. However, it’s crucial to acknowledge that this study is single cantered. A more extensive prospective study with larger sample size and longer follow-up periods are needed to validate these findings and to determine the full extent of the benefits of thrombus aspiration on cardiac function. Nonetheless, the current results provide encouraging evidence that PD+TA may be a valuable adjunctive technique in improving cardiac outcomes in STEMI patients.

5. Conclusion

Our current study highlights several significant findings regarding the use of pre-dilatation and thrombus aspiration (PD+TA) in STEMI patients undergoing PPCI. The PD+TA group exhibited better acute angiographic outcomes, including improved TIMI 3 flow rates and reduced ST segment elevation compared to the NOTA group. Moreover, the PD+TA group showed a statistically significant improvement in ejection fraction at one-month follow-up, indicating potential benefits in cardiac function recovery. These findings underscore the potential of PD+TA to optimize coronary blood flow, enhance myocardial salvage, and potentially improve clinical outcomes in STEMI patients. Further research with larger cohorts and longer follow-up durations is warranted to confirm these observations and establish definitive guidelines for the use of thrombus aspiration in STEMI management.