The high zero-flow pressure phenomenon in coronary circulation: a simulation study.

Tahseen Ejaz; Tadashi Takemae; Yukio Kosugi; Minoru Hongo

doi:10.1163/156855701321138978

Home/Archive/PubMed

PubMed · 12735432

The high zero-flow pressure phenomenon in coronary circulation: a simulation study.

Tahseen Ejaz·Tadashi Takemae·Yukio Kosugi·Minoru Hongo

View original source ↗Export metadata ↓

Abstract

A dynamic simulation was performed in order to study the high zero-flow pressure phenomenon by using an electronic model of the coronary vessel. The objective of this study was to establish a relationship between the diastolic arterial pressure and diastolic arterial flow. The simulated study showed that this relationship is approximately linear with a zero flow pressure intercept of approximately 40 mmHg. This result is consistent with the results obtained in animal experimentation conducted by others.

Explore related subjects

Arteries Blood Flow Velocity Blood Pressure Compliance Computer Simulation Coronary Circulation Coronary Vessels Diastole Humans Models, Cardiovascular Sensitivity and Specificity Vascular Resistance Evaluation Study Journal Article

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

Tahseen Ejaz, Tadashi Takemae, Yukio Kosugi, Minoru Hongo. 2002. The high zero-flow pressure phenomenon in coronary circulation: a simulation study.. https://doi.org/10.1163/156855701321138978

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2007

Monitoring medical procedures by exponential smoothing.

A new exponentially weighted moving average (EWMA) control chart well suited for 'online' routine surveillance of medical procedures is introduced. The chart is based on inter-event counts for failures recorded when the failures occur. The method can be used for many types of hospital procedures and activities, such as problems or errors in surgery, hospital-acquired infections, erroneous handling or prescription of medicine, deviations from scheduled treatments causing inconveniences for patients. The construction, the use and the effectiveness of the control chart are demonstrated by two well-known examples about wound infection in orthopaedic surgery and neonatal arterial switch surgery. The method is easy to implement and apply, it illustrates, estimates and tests the current failure rate. Comparisons with two examples from the literature indicate that its ability to quickly detect an increased failure rate is comparable to that of other well-established methods.

Arteries↗

PubMed2007

Acute atherosis in decidual tissue: not associated with systemic oxidative stress in preeclampsia.

The aim of this study was to explore a possible association between the presence of decidual acute atherosis, maternal hyperlipidaemia and oxidative stress in the maternal circulation in preeclamptic and uneventful pregnancies. Decidual tissue was harvested by a vacuum suction technique following delivery of the baby and placenta in 102 caesarean deliveries. Maternal plasma lipid profile and concentration of 8-isoprostane, a marker of oxidative stress, was analysed. Acute atherosis was present in 42% of the preeclamptic patients with identified spiral arteries. CD68 positive foam cells were found in the spiral artery walls in 14% of the normal pregnancies. We have previously demonstrated an elevated plasma level of 8-isoprostane in the preeclampsia group, as compared to the uneventful pregnancy group (218 vs. 354 pg/mL, p=0.02). Presence of acute atherosis was, however, not associated with an elevated level of oxidative stress in the maternal circulation, measured as 8-isoprostane. In conclusion, the presence of decidual vascular changes in the form of acute atherosis is not necessarily paralleled by hyperlipidaemia or augmented oxidative stress in the maternal systemic circulation. This study adds to the notion of preeclampsia being a multifactorial disease with a variety of clinical forms.

Arteries↗

PubMed2007

Relation between branching patterns and perfusion in stochastic generated coronary arterial trees.

Biological variation in branching patterns is likely to affect perfusion of tissue. To assess the fundamental consequences of branching characteristics, 50 stochastic asymmetrical coronary trees and one non-stochastic symmetrical branching tree were generated. In the stochastic trees, area growth, A, at branching points was varied: A = random; 1.00; 1.10; 1.13 and 1.15 and symmetry, S, was varied: S = random; 1.00; 0.70; 0.58; 0.50 and 0.48. With random S and A values, a large variation in flow and volume was found, linearly related to the number of vessels in the trees. Large A values resulted in high number of vessels and high flow and volume values, indicating vessels connected in parallel. Lowering symmetry values increased the number of vessels, however, without changing flow, indicating a dominant connection of vessels in series. Both large A and small S values gave more realistic gradual pressure drops compared to the symmetrical non-stochastic branching tree. This study showed large variations in tree realizations, which may reflect real biological variations in tree anatomies. Furthermore, perfusion of tissue clearly depends on the branching rules applied.

Arteries↗