In vivo adaptive response of the peripheral conduit artery in patients with borderline systolic hypertension / 中华医学杂志(英文版)

<p><b>OBJECTIVE</b>To investigate elastic changes of the radial artery, a medium-sized muscular peripheral conduit artery, in patients with borderline systolic hypertension.</p><p><b>METHODS</b>Using a non-invasive high-resolution echo-tracking device coupled to a photoplethysmography (Finapres system) allowing simultaneous arterial diameter and finger blood pressure monitoring, we measured radial artery elastic parameters of 20 patients with borderline systolic hypertension and 20 normal subjects according to Langewouters model.</p><p><b>RESULTS</b>The diameter of the radial artery of control subjects and those with borderline systolic hypertension at the isobaric level of 100 mmHg and mean arterial pressure was similar, but the compliance and distensibility at similar conditions in patients with borderline systolic hypertension did not further reduced and even increased.</p><p><b>CONCLUSION</b>In patients with borderline systolic hypertension, the adaptive responses of the radial artery compliance and distensibility to increased pressure were directed to maintain its elasticity, contributing to the homeostasis of the cardiovascular system.</p>

Effects of external counterpulsation on the pulsatility of blood pressure and blood flow in dogs / 生物医学工程学杂志

Pulsatile blood flow plays an important role in maintaining normal vascular endothelial function. Quantitative measurement of pulsatility of artery blood pressure and blood flow in dogs and effects of enhanced external counterpulsation (EECP) on the pulsatility were taken in this study. Common carotid artery blood pressure and blood flow were measured in 6 beagle dogs that had suffered from an acute myocardial infarction 6 weeks before. A 6F tip transducer catheter was inserted into the right common carotid artery to measure blood pressure, and blood flow was measured in the left common carotid artery by an electromagnetic blood flow probe under anesthesia before and during EECP. Blood pulse pressure, pulsatility index (ratio of peak pressure to end diastolic pressure) and standard deviation of blood pressure were calculated to evaluate the pulsatility of arterial blood pressure. Blood pulse flow, pulsatility index (ratio of peak flow to trough flow) and standard deviation of blood flow were calculated to evaluate the pulsatility of blood flow. Mean vascular resistance (MVR) was calculated as MVR = mean blood pressure/mean blood flow. Blood pulse pressure, pulsatility index and standard deviation of blood pressure were elevated from 30 +/- 9 mmHg, 1.26 +/- 0.05 and 8.7 +/- 2.5 mmHg to 43 +/- 8 mmHg (P < 0.05), 1.54 +/- 0.13 and 12.4 +/- 2.0 mmHg (P < 0.05) before and during EECP, respectively. Blood pulse flow, pulsatility index and standard deviation of blood flow were elevated from 317 +/- 48 ml/min, 2.85 +/- 0.21 and 96 +/- 21 ml/min to 447 +/- 88 ml/min, 4.56 +/- 0.90 and 131 +/- 39 ml/min before and during EECP (P < 0.05). MVR was decreased from 578 +/- 72 before EECP to 476 +/- 85 Wood units during EECP(P < 0.05). These data demonstrate that EECP gives an elevation of pulsatility to blood pressure and blood flow, thus it may lead to the decrease of vascular resistance.

Effects of external counterpulsation on the pulsatility of blood pressure in human subjects / 生物医学工程学杂志

Pulsatile blood flow plays an important role in maintaining normal vascular endothelial function. Quantitative measurement of pulsatility of human arterial blood pressure and the influence of enhanced external counterpulsation (EECP) on the pulsatility were investigated in this study. Eight healthy young male volunteers aged 22 to 35 were included. A 4F tip transducer catheter was inserted under local anaesthesia into the radial artery up to the aortic arch. Intraarterial blood pressure was recorded before and during EECP. Blood pulse pressure, pulsatility index (ratio of peak pressure to end diastolic pressure) and standard deviation of blood pressure in 5 cardiac cycle was calculated to evaluate the pulsatility of arterial blood pressure. The results showed that blood pulse pressure, pulsatility index and standard deviation of blood pressure were elevated from 47 +/- 5 mmHg, 1.64 +/- 0.11 and 13.6 +/- 1.5 mmHg to 77 +/- 3 mmHg, 2.46 +/- 0.25 and 19.3 +/- 2.2 mmHg before and during EECP respectively (P < 0.05). Decreasing of systolic pressure and increasing of diastolic pressure during counterpulsation were also observed. EECP gives an elevation of pulsatility to human blood pressure.