Measuring coronary arterial compliance and vasomotor response noninvasively in clinical and research settings

This study analyzed the relationship between pulmonary vascular resistance (PVR) and pulmonary arterial compliance ( Ca) in patients with idiopathic pulmonary arterial hypertension (IPAH) and proximal chronic thromboembolic pulmonary hypertension (CTEPH). It has recently been shown that the time constant of the pulmonary circulation (RC time constant), or PVR × Ca, remains unaltered in various forms and severities of pulmonary hypertension, with the exception of left heart failure. We reasoned that increased wave reflection in proximal CTEPH would be another cause of the decreased RC time constant. We conducted a retrospective analysis of invasive pulmonary hemodynamic measurements in IPAH ( n = 78), proximal CTEPH ( n = 91) before (pre) and after (post) pulmonary endarterectomy (PEA), and distal CTEPH ( n = 53). Proximal CTEPH was defined by a postoperative mean pulmonary artery pressure (PAP) of ≤25 mmHg. Outcome measures were the RC time constant, PVR, Ca, and relationship between systolic and mean PAPs. The RC time constant for pre-PEA CTEPH was 0.49 ± 0.11 s compared with post-PEA-CTEPH (0.37 ± 0.11 s, P < 0.0001), IPAH (0.63 ± 0.14 s, P < 0.001), and distal CTEPH (0.55 ± 0.12 s, P < 0.05). A shorter RC time constant was associated with a disproportionate decrease in systolic PAP with respect to mean PAP. We concluded that the pulmonary RC time constant is decreased in proximal CTEPH compared with IPAH, pre- and post-PEA, which may be explained by increased wave reflection but also, importantly, by persistent structural changes after the removal of proximal obstructions. A reduced RC time constant in CTEPH is in accord with a wider pulse pressure and hence greater right ventricular work for a given mean PAP.

Download Full-text

Three‐dimensional assessment of brain arterial compliance: Technical development, comparison with aortic pulse wave velocity, and age effect

Magnetic Resonance in Medicine ◽

10.1002/mrm.28835 ◽

2021 ◽

Author(s):

Yang Li ◽

Chantelle Lim ◽

Michael Schär ◽

Dengrong Jiang ◽

Ye Qiao ◽

...

Keyword(s):

Pulse Wave Velocity ◽

Wave Velocity ◽

Pulse Wave ◽

Arterial Compliance ◽

Three Dimensional ◽

Aortic Pulse Wave Velocity ◽

Age Effect ◽

Technical Development ◽

Dimensional Assessment

Download Full-text

A square-pulse flow method for measuring characteristics of the arterial bed

Journal of Applied Physiology ◽

10.1152/jappl.1976.40.3.425 ◽

1976 ◽

Vol 40 (3) ◽

pp. 425-433 ◽

Cited By ~ 3

Author(s):

M. G. Bottomley ◽

G. W. Mainwood

Keyword(s):

Arterial Compliance ◽

Peripheral Resistance ◽

Mean Value ◽

Pressure Response ◽

Arterial System ◽

Response Curves ◽

Arterial Tree ◽

Pulse Flow ◽

Critical Closing Pressure ◽

Closing Pressure

A device was designed to provide a “square” pulse of blood flow into the arterial system. Pulses were injected into the carotid artery of the rabbit during transient cardiac arrest. Analysis of pressure response curves generated by the flow provides information as to the state of the arterial tree. With certain assumptions it is possible to estimate from these curves lumped values of peripheral resistance, critical closing pressure, and arterial compliance. In a series of 12 rabbits the mean value of peripheral resistance was found to be 0.21 +/- 0.7 mmHg-ml-1-min and critical closing pressure was estimated to be 23.6 +/- 3.8 mmHg. This method gives two possible values for arterial compliance 0.036 +/- 0.010 and 0.055 +/- 0.010 ml-mm-1 based, respectively, on the rise and decay curves of the pressure response. The theory and limitations of the method are discussed. The use of the method is illustrated in following the response to increased PCO2 and hemorrhage.

Download Full-text

Effects of heat-not-burn compared to combustible cigarettes on coronary flow, myocardial work index and vascular function

European Heart Journal - Cardiovascular Imaging ◽

10.1093/ehjci/jeaa356.098 ◽

2021 ◽

Vol 22 (Supplement_1) ◽

Author(s):

I Ikonomidis ◽

K Katogiannis ◽

D Vlastos ◽

G Kostelli ◽

K Kourea ◽

...

Keyword(s):

Oxidative Stress ◽

Platelet Activation ◽

Vascular Function ◽

Coronary Flow ◽

Arterial Compliance ◽

Chronic Phase ◽

Protein Carbonyls ◽

Flow Reserve ◽

Work Index ◽

Chronic Study

Abstract Funding Acknowledgements Type of funding sources: None. Aim/Introduction: Heat-not-burn cigarette (HNBC) constitutes a non-combustible smoke product. Purpose We compare the effects of heat-not-burn and conventional cigarettes on coronary flow, myocardial and vascular function, platelet activation and oxidative stress. Methods We compared the effects of HNBC to those of tobacco cigarette (TCig), on arterial stiffness, oxidative stress, and platelet activation, acutely and after 1 month of switching to HNBC, as well as on endothelial, myocardial, and coronary function after 1 month of switching to HNBC. In the acute study, 50 smokers were randomized into smoking a single Tcig or an HNBC and after 60 minutes were crossed over to the alternate smoking (HNBC or Tcig). For the chronic phase, 75 smokers were examined. Of those, 50 were switched to HNBC and 25 continued Tcig for 1 month. Pulse wave velocity (PWV) and biomarkers [malondialdehyde (MDA), protein carbonyls (PC), and thromboxane B2 (TXB2)] were assessed in the acute and chronic study. Myocardial deformation [global longitundinal strain (GLS), myocardial work index (GWI) and wasted myocardial work (GWW)], coronary flow reserve (CFR) by Doppler echocardiography, total arterial compliance (TAC), and flow-mediated dilation (FMD) were additionally assessed in the chronic study. Results Compared to baseline, TCig smoking acutely increased exhaled CO, PWV, MDA, and TxB2 (p < 0.05), while no changes were observed after HNBC. Compared to resuming Tcig smoking, switching to HNBC for 1 month improved CO (mean change: -55% vs -2.4%), FMD ( +55% vs +15%), CFR (+46% vs +4%), TAC (+9% vs -0.5%), GLS (+6% vs +1%), GWW (-19% vs +0.5%), MDA (-19% vs 1 %), and TxB2 (-12% vs 4%) (p < 0.05 for all comparisons). Conclusions HNBCs exert a less detrimental effect on vascular, cardiac and platelet function than combustible tobacco.

Download Full-text

Vascular-ventricular coupling during exercise is not affected by exaggerated blood pressures in endurance-trained athletes

Journal of Applied Physiology ◽

10.1152/japplphysiol.00108.2019 ◽

2019 ◽

Vol 127 (3) ◽

pp. 753-759 ◽

Cited By ~ 1

Author(s):

Katharine D. Currie ◽

Zion Sasson ◽

Jack M. Goodman

Keyword(s):

Blood Pressure ◽

Vascular Function ◽

Arterial Compliance ◽

Left Ventricular ◽

Left Ventricular Volumes ◽

Peripheral Vascular ◽

Arterial Elastance ◽

Coupling Index ◽

Cardiovascular Performance ◽

Stage 1

This study sought to examine whether cardiovascular performance during exercise, assessed using the vascular-ventricular coupling index (VVC), was affected by exaggerated blood pressure (EBP) responses in endurance-trained athletes. Subjects were middle-aged endurance-trained men and women. Blood pressure measurements and left ventricular echocardiography were performed in a semiupright position at rest and during steady-state cycling at workloads that elicited 100–110 beats/min ( stage 1) and 130–140 beats/min ( stage 2). These data were used to calculate effective arterial elastance index ( EaI), left ventricular end-systolic elastance index ( ELVI), and their ratio (VVC). Additional measurements of left ventricular volumes and function (i.e., stroke volume, cardiac output, and longitudinal strain) and indirect assessments of peripheral vascular function (i.e., total arterial compliance and peripheral vascular resistance) were examined. Fourteen subjects with EBP (EBP+, 50% men) and 14 sex-matched subjects without EBP (EBP−) participated, with results presented as EBP+ versus EBP−. EaI and ELVI increased from rest to exercise while VVC decreased, but only ELVI was different between groups at stage 1 [7.6 (1.8) vs. 6.4 (1.0) mmHg·ml−1·m−2, P = 0.045] and stage 2 [10.3 (1.6) vs. 8.0 (1.7) mmHg·ml−1·m−2, P < 0.001]. Additional comparisons revealed no group difference in the contribution of the Frank-Starling mechanism or left ventricular and peripheral vascular function during exercise. The cardiovascular adjustment to exercise in athletes with EBP is achieved through a matched increase in both EaI and ELVI, and the absence of between-group differences in left ventricular or peripheral vascular function suggests that other factors may contribute to the EBP response. NEW & NOTEWORTHY Cardiovascular performance during submaximal exercise, assessed using vascular-ventricular coupling, is unaffected by exaggerated blood pressure (EBP) responses in endurance-trained athletes. The underlying mechanisms of EBP in athletes remain unknown as changes in left ventricular and peripheral vascular function during exercise were similar in athletes with and without EBP.

Download Full-text