Carotid-radial pulse wave velocity as a discriminator of intrinsic wall alterations during evaluation of endothelial function by flow-mediated dilatation

Role of arterial impairment in preeclampsia: should the paradigm shift?

Preeclampsia is a worldwide pregnancy complication with serious short- and long-term maternal and neonatal consequences. Our understanding of preeclampsia pathophysiology has significantly evolved over the last decades with the recognition that impaired arterial function and structure may occur early in the course of pregnancy, preceding the clinic-humoral syndrome and driving long-term cardiovascular disease risk in the future of these patients. Although an early abnormal placentation may be the inciting event for a large proportion of cases, there is growing evidence that challenges the placental hypothesis in all affected women, since placental histopathology lesions thought to be characteristic are neither sensitive nor specific markers for the disorder. Recent hemodynamic investigations and studies on left ventricular function and structure in women with preeclampsia further challenge this universal paradigm and propose that placental dysfunction could be secondary to a maternal cardiovascular maladaptation to pregnancy in certain patients. Supporting this hypothesis, certain vascular features, which are characteristically enhanced in normal pregnancy allowing a healthy vascular adaptation, are absent in preeclampsia and comparable to the nonpregnant population. However, arterial biomechanics in preeclampsia may only not cope with hemodynamic demands of pregnancy but also impose additional detrimental loads to the maternal heart ("impaired left-ventricle-aorta coupling") and transmit pressure and flow disturbances into the fetoplacental circulation ("impaired large arteries-microcirculation coupling"). In this review, we analyze the major role of the arterial dysfunction in the cardiovascular maladaptation hypothesis of preeclampsia, shed light on its potential etiopathogenic link, and discuss the complementary nature of the placental and cardiovascular theories.

Response of peripheral arterial pulse wave velocity to acute exercise in patients after recent myocardial infarction and healthy controls

Background

Many studies found increased central arterial stiffness and poor endothelial function in patients with coronary artery disease (CAD). Acute exercise has been shown to decrease peripheral pulse wave velocity (pPWV) in young healthy volunteers. We hypothesized the response to acute exercise to be diminished in CAD patients compared to healthy young (HY) and age-matched (HAM) controls.

Methods

In 21 patients after recent myocardial infarction (CAD), 11 HAM and 10 HY pPWV was measured by applanation tonometry at the proximal femoral artery and the posterior tibial artery at rest and from 5 to 15 min after cessation of exhaustive exercise. Heart rate (HR) and blood pressure (BP) were monitored continuously. Resting central PWV (cPWV) was measured between the carotid and femoral arteries. Resting values and reponses to acute exercise were compared between the three groups and predictors for pPWV response were sought.

Results

The response in pPWV to acute exercise seen in HY (lowering in pPWV by 17%) was absent in both CAD and HAM. Resting pPWV was not statistically different between the three groups, while cPWV was comparable in CAD and HAM but 17% lower in HY. Predictors for response in pPWV to exercise were age (Spearman r = 0.48), cPWV (r = 0.34) and response in diastolic BP (r = 0.32).

Conclusion

The response in pPWV to acute exercise observed in HY was absent in CAD and HAM. In dilated peripheral arteries, PWV may reflect stiffness of passive vessel structures, which are likely to increase with age in healthy persons and CAD alike.

Normal Pregnancy Is Associated with Changes in Central Hemodynamics and Enhanced Recruitable, but Not Resting, Endothelial Function

Introduction. Flow-mediated dilation (FMD), low flow-mediated constriction (L-FMC), and reactive hyperemia-related changes in carotid-to-radial pulse wave velocity (ΔPWVcr%) could offer complementary information about both “recruitability” and “resting” endothelial function (EF). Carotid-to-femoral pulse wave velocity (PWVcf) and pulse wave analysis-derived parameters (i.e., AIx@75) are the gold standard methods for noninvasive evaluation of aortic stiffness and central hemodynamics. If healthy pregnancy is associated with both changes in resting and recruitable EF, as well as in several arterial parameters, it remains unknown and/or controversial. Objectives. To simultaneously and noninvasively assess in healthy pregnant (HP) and nonpregnant (NP) women central parameters in conjunction with “basal and recruitable” EF, employing new complementary approaches. Methods. HP (n = 11, 34.2 ± 3.3 weeks of gestation) and age- and cardiovascular risk factors-matched NP (n = 22) were included. Aortic blood pressure (BP), AIx@75, PWVcf, common carotid stiffness, and intima-media thickness, as well as FMD, L-FMC, and ΔPWVcr %, were measured. Results. Aortic BP, stiffness, and AIx@75 were reduced in HP. ΔPWVcr% and FMD were enhanced in HP in comparison to NP. No differences were found in L-FMC between groups. Conclusion. HP is associated with reduced aortic stiffness, central BP, wave reflections, and enhanced recruitable, but not resting, EF.

Descriptive study of possible link between cardioankle vascular index and homocysteine in vascular-related diseases

OBJECTIVES

Cardioankle vascular index (CAVI) is a new index of arterial stiffness independent of immediate blood pressure. Homocysteine (Hcy) is an independent risk factor for vascular diseases. The aim of this study was to investigate the relationship between Hcy and CAVI in the vascular-related diseases.

DESIGN

Descriptive research.

PARTICIPANTS

88 patients (M/F 46/42) with or without hypertension, coronary artery disease or arteriosclerosis obliterans were enrolled to our study. They were divided into two groups according to the level of Hcy.

METHODS

CAVI, carotid-femoral pulse wave velocity (CF-PWV) and carotid-radial pulse wave velocity (CR-PWV) were measured by VS-1000 and Complior apparatus.

RESULTS

There was significant correlation between Hcy and CF-PWV, CR-PWV, CAVI in the entire group (r=0.33, p=0.002; r=0.51, p<0.001; r=0.42, p<0.001, respectively). And there was significant correlation between Hcy and CF-PWV, CR-PWV, CAVI in the vascular-related disease group (r=0.23, p=0.048; r=0.51, p<0.001; r=0.392, p=0.001, respectively). The level of Hcy was significantly higher in patients with one or more vascular diseases than in patients without vascular diseases. The levels of CF-PWV, CR-PWV and CAVI were significantly higher in Hcy ≥15 μmol/l group than in Hcy <5 μmol/l group (13.7±3.0 vs 10.8±2.5, p < 0.001; 10.6±2.1 vs 9.2±1.6, p=0.001; 9.30±2.1 vs 7.79±2.1, p=0.001, respectively). Multiple linear regression showed that Hcy, body mass index (BMI) and age were independent associating factors of CAVI in the entire study group (β=0.421, p=0.001; β=-0.309, p=0.006; β=0.297, p=0.012, respectively). And Hcy, BMI and age were independent influencing factors of CAVI in the vascular-related disease group (β=0.434, p=0.001; β=-0.331, p=0.009; β=0.288, p=0.022, respectively).

CONCLUSIONS

CAVI was positively correlated with Hcy in the vascular-related diseases.

Hyperemia-Related Changes in Arterial Stiffness: Comparison between Pulse Wave Velocity and Stiffness Index in the Vascular Reactivity Assessment

Carotid-to-radial pulse wave velocity (PWV_cr) has been proposed to evaluate endothelial function. However, the measurement of PWV_cr is not without limitations. A new simple approach could have wide application. Stiffness index (SI) is obtained by analysis of the peripheral pulse wave and gives reproducible information about stiffness of large arteries. This study assessed the effects of hyperemia on SI and compared it with PWV_cr in 14 healthy subjects. Both were measured at rest and during 8 minutes after ischemia. SI temporal course was determined. At 1 minute, SI and PWV_cr decreased (5.58 ± 0.24 to 5.34 ± 0.23 m/s, P < 0.05; 7.8 ± 1.0 to 7.2 ± 0.9 m/s; P < 0.05, resp.). SI was positively related to PWV_cr in baseline (r = 0.62 , P < 0.05), at 1 minute (r = 0.79, P < 0.05), and during the whole experimental session (r = 0.52, P < 0.05). Conclusion. Hyperemia significantly decreases SI in healthy subjects. SI was related to PWV_cr and could be used to facilitate the evaluation of hyperemia-related changes in arterial stiffness.

Carotid-radial pulse wave velocity as an alternative tool for the evaluation of endothelial function during pregnancy: potential role in identifying hypertensive disorders of pregnancy

Preeclampsia/eclampsia syndrome, a major cause of maternal mortality and morbidity, has been recognized as a condition with a globally impaired endothelial function (EF). The possibility of identifying early subclinical endothelial damage during pregnancy could be of value in classifying the different hypertensive states of pregnancy, and have a positive impact in the understanding of this syndrome, as well as on the appropriate treatment of these patients. Reactive hyperemia-related changes in carotid-radial pulse wave velocity (PWVcr) were proposed as an alternative tool for the evaluation of EF in patients with cardiovascular risk factors. If impaired EF, which follows hypertensive disorders of pregnancy can be assessed using PWVcr changes remains still unknown.

AIMS

To assess and compare reactive hyperemia-related changes in PWVcr and FMD in pregnant women (healthy and with hypertensive disorders) and non pregnant women.

METHODS

Healthy pregnant (HP; n=13), preeclamptic (PE; n=7), non-proteinuric hypertensive (NPH; n=6) and non-pregnant (NP; n=32) women were included. Left PWVcr (strain gauge mechano-transducers), left brachial arterial diameter (B-Mode ultrasound) and blood flow velocity (Doppler ultrasound) were measured before (baseline) and after the transient ischemia of the left forearm were determined.

RESULTS

One minute after the cuff deflation, PWVcr decreased in HP (6.9 ± 1.5 to 6.0 ± 0.9 m/s, p&#60;0.001) and in NP (8.1 ± 0.9 to 7.4 ± 0.9 m/s; p&#60;0.001). NPH showed a blunted hyperemic PWVcr response (6.6 ± 1.4 to 6.7 ± 1.0 m/s; p=0.91), whereas PE showed a tendency to increase (6.0 ± 0.7 to 6.4 ± 0.8 m/s; p=0.10). Reactive hyperemia PWVcr response (ΔPWVcr in %) differed comparing HP with NPH (-12% vs. +2%; p&#60;0.01) and with PE (-12 vs. +6%; p &#60;0.01), whereas no differences were found between NHP and PE (p=1.00).

CONCLUSION

HP showed an enhanced PWVcr reduction, whereas PE and NPH showed a blunted hyperemic PWVcr response. Carotid-radial PWVcr analysis could have a potential role in the assessment of pregnancy to study EF with a potential clinical application in predicting pregnancy induced hypertension and preeclampsia.