Brachial artery low-flow-mediated constriction is increased early after coronary intervention and reduces during recovery after acute coronary syndrome: characterization of a recently described index of vascular function

• Published in: European heart journal 2011-04, Vol.32 (7), p.856-866
• Main Authors: SPIRO, Jonathan R, DIGBY, Janet E, GHIMIRE, Gopal, MASON, Mark, MITCHELL, Andrew G, ILSLEY, Charles, DONALD, Ann, DALBY, Miles C. D, KHARBANDA, Rajesh K
• Format: Article
• Language: English
• Subjects: Acute Coronary Syndrome; Adult; Aged; Aged, 80 and over; Analysis of Variance; Angioplasty, Balloon, Coronary; Biological and medical sciences; Biomarkers - metabolism; Brachial Artery - diagnostic imaging; Brachial Artery - physiology; Cardiology. Vascular system; Clinical Research; Coronary heart disease; Cytokines - metabolism; Diseases of the cardiovascular system; Endothelin-1 - metabolism; Endothelium, Vascular - physiology; Female; Heart; Humans; Male; Medical sciences; Middle Aged; Myocardial Infarction - diagnostic imaging; Myocardial Infarction - physiopathology; Myocardial Infarction - therapy; Myocarditis. Cardiomyopathies; Radiotherapy. Instrumental treatment. Physiotherapy. Reeducation. Rehabilitation, orthophony, crenotherapy. Diet therapy and various other treatments (general aspects); Ultrasonography; Vasoconstriction - physiology; Vasodilation - physiology
• ISSN: 0195-668X; 1522-9645
• DOI: 10.1093/eurheartj/ehq401

The endothelium plays a role in regulating vascular tone. Acute and dynamic changes in low-flow-mediated constriction (L-FMC) and how it changes with regard to traditional flow-mediated dilatation (FMD) have not been described. We aimed to investigate the changes in brachial artery L-FMC following percutaneous coronary intervention (PCI) and during recovery from non-ST-segment elevation myocardial infarction (NSTEMI). FMD was performed in accordance with a previously described technique in patients before and after PCI and in the recovery phase of NSTEMI, but in addition, L-FMC data were acquired from the last 30 s of cuff inflation. About 135 scans were performed in 96 participants (10 healthy volunteers and 86 patients). Measurement of brachial L-FMC was reproducible over hours. L-FMC was greater among patients with unstable vs. stable coronary atherosclerosis (-1.33 ±1.09% vs. -0.03 ± 1.26%, P < 0.01). Following PCI, FMD reduced (4.43 ± 2.93% vs. 1.66 ± 2.16%, P < 0.01) and L-FMC increased (-0.33 ± 0.76% vs. -1.63 ± 1.15%, P = 0.02). Furthermore, during convalescence from NSTEMI, L-FMC reduced (-1.37 ± 1.19% vs. 0.01 ± 0.82%, P = 0.02) in parallel with improvements in FMD (2.54 ± 2.19% vs. 5.15 ± 3.07%, P < 0.01). Brachial L-FMC can be measured reliably. Differences were observed between patients with stable and unstable coronary disease. L-FMC was acutely increased following PCI associated with reduced FMD and, in the recovery from NSTEMI, L-FMC reduced associated with increased FMD. These novel findings characterize acute and subacute variations in brachial L-FMC. The pathophysiological and clinical implications of these observations require further study.