Naohisa Shindo

Relationship between Radial and Central Arterial Pulse Wave and Evaluation of Central Aortic Pressure Using the Radial Arterial Pulse Wave

Since a decrease of central aortic pressure contributes to the prevention of cardiovascular events, simple measurement of not only brachial blood pressure but also central aortic pressure may be useful in the prevention and treatment of cardiovascular diseases. In this study, we simultaneously measured radial artery pulse waves non-invasively and ascending aortic pressure invasively, before and after the administration of nicorandil. We then compared changes in central aortic pressure and radial arterial blood pressure calibrated with brachial blood pressure in addition to calculating the augmentation index (AI) at the aorta and radial artery. After nicorandil administration, the reduction in maximal systolic blood pressure in the aorta (Δa-SBP) was −14±15 mmHg, significantly larger than that in early systolic pressure in the radial artery (Δr-SBP) (−9±12 mmHg). The reduction in late systolic blood pressure in the radial artery (Δr-SBP2) was −15±14 mmHg, significantly larger than Δr-SBP, but not significantly different from Δa-SBP. There were significant relationships between Δa-SBP and Δr-SBP (r=0.81, p<0.001), and between Δa-SBP and Δr-SBP2 (r=0.91, p<0.001). The slope of the correlation regression line with Δr-SBP2 (0.83) was larger and closer to 1 than that with Δr-SBP (0.63), showing that the relationship was close to 1:1. Significant correlations were obtained between aortic AI (a-AI) and radial AI (r-AI) (before nicorandil administration: r=0.91, p<0.001; after administration: r=0.70, p<0.001). These data suggest that the measurement of radial artery pulse wave and observation of changes in the late systolic blood pressure in the radial artery (r-SBP2) in addition to the ordinary measurement of brachial blood pressure may enable a more accurate evaluation of changes in maximal systolic blood pressure in the aorta (a-SBP).

A flow-limiting stenosis is the major determinant of exercise-induced myocardial stunning in patients with coronary artery disease

BACKGROUND Although stress-induced myocardial stunning often develops after exercise testing, determinants of this phenomenon have not been evaluated. METHODS AND RESULTS Thirty-one patients with 1-vessel coronary artery disease, limited to the left anterior descending artery (LAD), were evaluated by quantitative coronary angiography (QCA) and intracoronary pressure measurements to calculate fractional flow reserve (FFR). In addition, electrocardiogram-gated technetium-99m sestamibi myocardial imaging was acquired >30 min after exercise and 4 h later to assess the development of stunning. Exercise-induced myocardial stunning was observed in 11 patients (35%). In patients with myocardial stunning, a summed stress score (17.3+/-7.1 vs. 8.1+/-6.2, p<0.001), summed difference score (10.3+/-4.1 vs. 2.7+/-1.9, p<0.0001), and wall motion difference score (4.8+/-2.8 vs. 0.9+/-1.1, p<0.0001) were greater than in those without, while diameter stenosis calculated by QCA (55.1+/-17.3% vs. 29.8+/-17.3%, p<0.0001) was greater and FFR reduced significantly (0.54+/-0.13 vs. 0.83+/-0.06, p<0.0001). Of note, 4 out of 21 patients (19%) with <50% LAD stenosis developed myocardial stunning, whereas only one patient with FFR of 0.64 or greater showed stunning. The best cut-off value was determined as 0.64 for FFR and 46% for QCA, providing 91% sensitivity and 100% specificity for FFR (chi-square=57.2), but 91% sensitivity and 80% specificity for diameter stenoses measured by QCA (chi-square=17.8). CONCLUSIONS The major determinant for exercise-induced myocardial stunning was a severe flow-limiting coronary stenosis, which was more important than anatomical evaluation based on luminal narrowing alone.