Exaggerated Aortic Pulse Pressure and Wave Amplitude During Muscle Metaboreflex Activation in Type 2 Diabetes Patients

BACKGROUND: Peripheral mean arterial pressure (MAP) responses to muscle metaboreflex activation using postexercise muscle ischemia (PEMI) in type 2 diabetes patients (T2D) are contradictory. Given that aortic pulse pressure (PP) and wave reflections are better indicators of cardiac load than peripheral MAP, we evaluated aortic blood pressure (BP) and wave amplitude during PEMI. METHODS: Aortic BP and pressure wave amplitudes were measured at rest and during PEMI following isometric handgrip at 30% maximum voluntary contraction (MVC) in 16 T2D and 15 controls. Resting aortic stiffness (carotid-femoral pulse wave velocity, cfPWV) and fasting blood glucose (FBG) were measured. RESULTS: Increases in aortic MAP (Delta26 +/- 2 mmHg vs. Delta17 +/- 2 mmHg), PP (Delta15 +/- 2 mmHg vs. Delta10 +/- 1 mmHg), augmentation index (AIx) (Delta8.2 +/- 1.0% vs. Delta4.5 +/- 1.3%), augmented pressure (AP) (Delta11 +/- 1 mmHg vs. Delta5 +/- 1 mmHg), forward (Pf) (Delta9 +/- 1 mmHg vs. Delta5 +/- 1 mmHg), and backward pressure waves (Pb) (Delta10 +/- 1 mmHg vs. Delta5 +/- 1 mmHg) responses to PEMI were greater in T2D than controls (P < 0.05). Aortic PP, but not MAP, response to PEMI was correlated to Pf (r = 0.63, P < 0.001) and Pb (r = 0.82, P < 0.001) responses and cfPWV (r = 0.37, P < 0.05). CONCLUSIONS: Aortic BP and pressure wave responses to muscle metaboreflex activation are exaggerated in T2D. Aortic PP during PEMI was related to increased wave reflection, forward wave amplitude, and aortic stiffness in T2D patients.