Effect of Intracoronary Adenosine on No Reflow in Patients with Acute ST Elevation Myocardial Infarction Undergoing Primary Percutaneous Coronary Intervention
Authors: Saad A , Raymond R , Elnozahy M 
Published: August 2023

Abstract

Background
When total coronary artery occlusion was found in the early hours of transmural myocardial infarction, most of our research interest and treatment strategies focused on epicardial coronary arteries. Little attention, however, is paid to the coronary microvasculature. When a coronary artery is occluded, detrimental changes occur in the cardiac capillaries and arterioles. After relief of the occlusion, blood flow to the ischemic tissue may still be impeded, a phenomenon known as no reflow. This abstract attempt to provide an in-depth understanding of this phenomenon and comparative review of intracoronary adenosine used in no reflow settings.

Aim and objectives
The aim of the study was to evaluate the impact of intracoronary adenosine on preventing no-reflow phenomenon as being assessed by tissue perfusion TIMI flow and myocardial blush grade as the primary objective in patients presented with ST elevation myocardial infarction (STEMI) undergoing primary PCI as the strategy of reperfusion and its effect on Left ventricular ejection fraction and LV dimensions as the secondary objective.

Patients and Methods
This study included 200 patients presented to emergency departments of Ain shams university hospitals from January 2021 till June 2022 and diagnosed with STEMI as being defined as Patients with ST elevation myocardial infarction defined as having symptoms of ischemia and ST-segment elevation of at least two contiguous leads with ST-segment elevation ≥ 2.5 mm in men &lt; 40 years, ≥2 mm in men ≥ 40 years, or ≥ 1.5 mm in women in leads V2–V3 and/or ≥ 1 mm in the other leads [1.2], that had been revascularized by primary PCI as per the recommendations of The European society of cardiology guidelines for diagnosis and management of ST elevation myocardial infarction published in 2017 [2]. The patients were randomized using dedicated software programme into two groups. Group A including 100 patients was the adenosine group. Group B including 100 patients was the standard control group.

Results
Our study had demonstrated that There was a statistically significant difference between the two groups, group A (Adenosine group) and group B (control group), regarding the occurrence of no reflow as there were 12 no reflow cases in group A versus 23 no reflow cases in group B with P value of 0.041). Off note, in our study no reflow was defined as TIMI score of &lt; 3 and MBG grade of 0, 1, 2 in the absence of evident vessel dissection, obstruction or distal vessel embolic cutoff. There was a highly significant difference between the two groups in the tissue perfusion post primary PCI as being assessed by TIMI flow classification and myocardial blush grade. As for TIMI flow grading; TIMI I flow was achieved in 4 patients in group A versus 7 patients in group B, TIMI II flow was achieved in 10 patients in group A versus 44 patients in group B, TIMI III flow was achieved in 86 patients in group A versus 49 patients in group B, with P value of 0.000. As regard myocardial blush grade; MBG 0 was achieved in 3 patients in group A versus 5 patients in group B, MBG I was achieved 2 patients in group A versus 5 patients in group B, MBG II was achieved in 27 patients in group A versus 48 patients in group B, MGB III was achieved in 68 patients in group A versus 42 patients in group B, with P value of 0.003.

Conclusion
We concluded that intracoronary adenosine may be used for prevention of no reflow in patients presented with STEMI undergoing primary PCI as reperfusion strategy. Intracoronary adenosine was associated with better myocardial salvage in the context of left ventricular ejection fraction and dimensions. Tissue perfusion as being assessed by TIMI flow grade and MBG was inversely related to the reduction of LVEF.