Objective: The vasoconstrictor component of atherothrombotic culprit lesions in ST-elevation myocardial infarction (STEMI) patients has not been fully investigated. This study was aimed at assessing the vasoconstrictor component of atherothrombotic culprit lesions in patients with STEMI receiving primary percutaneous coronary intervention (PCI).
Methods: A group of 100 patients with STEMI were enrolled prospectively. Baseline coronary angiography achieving normal antegrade flow was followed by 200 μg of intracoronary nitroglycerin (NTG) injection and repeat coronary angiography at the same projection view for culprit lesions was performed. End points were the changes in lesion length, reference vessel diameter, minimal lumen diameter, and diameter stenosis by quantitative coronary analysis before and after NTG injection.
Results: Reference vessel diameter (2.7 ± 0.5 mm vs. 2.9 ± 0.5 mm, p < 0.001) and minimal lumen diameter (0.9 ± 0.4 mm vs. 1.2 ± 0.5 mm, p < 0.001) increased after NTG injection, whereas lesion length (24.1 ± 7.4 mm vs. 23.4 ± 7.6 mm, p = 0.001) and diameter stenosis (66.6 ± 14.8% vs. 58.3 ± 16.1%, p < 0.001) decreased. The median percentage change of diameter stenosis was -4.0% (Interquartile range: -13.8% to -1.0%), which was used as the cut-off value to divide the cohort into NTG responder or nonresponder groups accordingly. Total stent length was significantly shorter in the responder group compared with the nonresponder group (27.4 ± 11.6 mm vs. 33.7 ± 16.8 mm, p = 0.042).
Conclusion: This study showed the presence of a vasoconstrictor component in atherothrombotic culprit lesions in STEMI patients receiving primary PCI. Vasodilating effort by NTG may decrease stent length used for culprit lesions.
Keywords: Intracoronary vasodilator; Nitroglycerin; Quantitative coronary analysis; ST-segment elevation myocardial infarction; Vasoconstriction.