Journal of cardiovascular pharmacology
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J. Cardiovasc. Pharmacol. · Feb 2008
Towards new indices of arterial stiffness using systolic pulse contour analysis: a theoretical point of view.
Total arterial stiffness plays a contributory role throughout aging and in numerous cardiovascular diseases, including hypertension. Aortic stiffening is responsible for an increased characteristic impedance (ie, the impedance to the left ventricular pulsatile flow), thus increasing the forward pressure-wave amplitude that contributes to pulse pressure elevation. Aortic stiffening also increases pulse wave velocity, and this results in anticipated and enhanced wave reflections, further augmenting central pulse pressure. ⋯ This allowed us to describe new time-domain estimates of characteristic impedance, pulsatile load (waveguide ratio), total arterial compliance, and total arterial stiffness. It is demonstrated that total arterial stiffness may be estimated by the following formula: [(Pi - DAP) x ST] / (SV x Deltat), where Pi is the aortic pressure at the inflection point (peak forward pressure wave), DAP is diastolic aortic pressure, ST is systolic ejection time, SV is stroke volume, and Deltat is the time-to-Pi. A mathematical relationship among time intervals and indices of pulsatile load is demonstrated, and the clinical implications are discussed in terms of cardiovascular risk and stroke volume prediction.
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J. Cardiovasc. Pharmacol. · Feb 2008
Possible involvement of erythropoietin in remote renal preconditioning-induced cardioprotection in rats.
Remote preconditioning is a unique phenomenon in which brief episodes of ischemia and reperfusion to remote organs protect the target organ against sustained ischemia/reperfusion (I/R)-induced injury. Protective effects of remote renal preconditioning are well established in the heart, but their mechanisms still remain to be elucidated. Hence, the present study was designed to investigate the possible involvement of erythropoietin in remote renal preconditioning (RRPC)-induced cardioprotection in rats. ⋯ However, cardioprotective effects of RRPC were not observed in renal failure rats, indicating the protective role of humoral factor was released from functional kidneys. In renal failure rats, exogenous administration of rhEPO (5,000 IU/kg intraperitoneal) with RRPC restored the cardioprotective effects of later. These results implicate that RRPC-induced cardioprotective effects may be mediated through release of erythropoietin from kidney.