Association of changes of pulse wave velocity and augmentation index after isometric handgrip exercise with coronary lesion extent and revascularization

Abstract

Background: Arterial stiffness is associated with myocardial ischemia and incident coronary artery disease (CAD), and indexes of arterial stiffness are usually increased in patients with CAD. However, these indexes are often increased in elderly without CAD. Arterial stiffness in patients with CAD may become more evident after isometric handgrip exercise which increases systolic pressure and ventricular afterload. We investigated the association of the change of stiffness indexes after isometric handgrip exercise with the lesion extent of CAD and the necessity for coronary revascularization.

Methods: Patients who were scheduled a routine coronary angiography via a femoral artery were enrolled. Arterial waveforms were traced at aortic root and external iliac artery using coronary catheters at baseline and 3 min after handgrip exercise. Augmentation index (AIx) was measured on the recorded aortic pressure waveform, and pulse wave velocity (PWV) was calculated using the ECG-gated time difference of the upstroke of arterial waveforms and distance between aortic root and external iliac artery.

Results: Total 37 patients were evaluated. Both PWV and AIx increased after handgrip exercise. ΔPWV was significantly correlated with ΔAIx (r = 0.344, P = 0.037). Patients were divided into higher and lower ΔPWV or ΔAIx groups based on the median values of 0.4 m/sec and 3.3%, respectively. Patients with higher PWV had more 2- or 3-vessel CAD (69% vs. 27%, P = 0.034), and underwent percutaneous coronary intervention (PCI) more frequently (84% vs. 50%, P = 0.038), but higher ΔAIx was not associated with either the lesion extent or PCI. Area under curve (AUC) of ΔPWV in association with PCI by C-statistics was 0.70 (95% confidence interval [CI] 0.51-0.88; P = 0.056). In multiple logistic regression analysis, ΔPWV was significantly associated with PCI (odds ratio 7.78; 95% CI 1.26-48.02; P = 0.027).

Conclusions: Higher ΔPWV after isometric handgrip exercise was associated with the lesion extent of CAD and the necessity for coronary revascularization, but higher ΔAIx was not.

Keywords: Arterial stiffness; Isometric exercise; Percutaneous coronary intervention; Pulse wave analysis; Pulse wave velocity.

Fig. 1

Measurements of augmentation index (AIx), and pulse wave velocity (PWV). Forward pressure (FP) was measured at a merging point of the forward and the reflected waves on the recorded aortic pressure waveform. AIx was defined as augmentation pressure (AP) divided by central pulse pressure (PP), and expressed as a percentage. PWV was calculated using the ECG-gated time difference of the upstroke of the arterial waveforms between the aortic root (T_AO) and the external iliac artery (T_IA), and the distance between them determined by a tape measure of the catheter length after removal of a coronary catheter. DBP; diastolic blood pressure, SBP; systolic blood pressure

Fig. 2

Correlation between changes of pulse wave velocity (ΔPWV) and augmentation index (ΔAIx) after isometric handgrip exercise. The median values of ΔPWV and ΔAIx were 0.4 m/sec and 3.3%, respectively

Fig. 3

Area under curve (AUC) with 95% confidence interval (CI) of Δpulse wave velocity (PWV) or Δaugmentation index (AIx) in association with percutaneous coronary intervention by C-statistics