Impact of age and hyperglycemia on the mechanical behavior of intact human coronary arteries: an ex vivo intravascular ultrasound study

Abstract

Despite their advantages, percutaneous coronary interventional procedures are less effective in diabetic patients. Changes in the mechanical properties of vascular walls secondary to long-term hyperglycemia as well as other factors such as age may influence coronary distensibility. This investigation is aimed at deciphering the extent of these effects on distensibility of postmortem human coronary arteries in a controlled manner. Excised human left anterior descending (LAD) coronary arteries were obtained within 24 h postmortem. With the use of intravascular ultrasound, vascular deformation was analyzed at midregions of 51 moderate lesions. Intraluminal pressure was systematically altered using a computerized pressure pump system and monitored by a pressure-sensing guidewire. Distensibility, a normalized compliance term, was defined as the change in lumen area normalized by the initial reference area over a given pressure interval. With the use of multivariate analysis and repeated-measures ANOVA, coronary distensibility was independently influenced by hyperglycemia and age (P < 0.05) through the entire pressure range. Within physiological pressure range, distensibility was significantly reduced with age in nonhyperglycemic coronary specimens (10.55 +/- 4.41 vs. 6.99 +/- 2.45, x10(3) kPa(-1), P = 0.01), whereas the hyperglycemic vessels were stiff even in the younger group (7.90 +/- 5.82 vs. 7.20 +/- 3.36, x10(3) kPa(-1), P = 0.79). Similar results were observed with stiffness index and elastic modulus of the arteries. Hyperglycemia and age independently influenced the distensibility of moderately atherosclerotic LAD coronary arteries. The stiffening with age was overshadowed in the hyperglycemic group by as-yet-undetermined factors.

Mechanical properties of human coronary arteries

“…Maybe the most complete in-vitro work has been carried out by Ozolanta et al [12]; they studied in 205 patients the evolution with age of distensibility and modulus of elasticity of coronary arteries in the 0-240 mmHg pressure range. Similar research was performed by Williams et al [10] (in-vivo) and Tajaddini et al [11] (in-vitro), which showed -in agreement with Ozolanta et al [12]-that distensibility decreases and the modulus of elasticity increases with age. To the authors' knowledge, most of the mechanical studies on human coronary arteries in the literature have been limited to compliance and stiffness measurements not beyond twice or three times physiological pressure.…”

Response of human coronary arteries at different mechanical conditions

“…Maybe the most complete in-vitro work has been carried out by Ozolanta et al [12]; they studied in 205 patients the evolution with age of distensibility and modulus of elasticity of coronary arteries in the 0-240 mmHg pressure range. Similar research was performed by Williams et al [10] (in-vivo) and Tajaddini et al [11] (in-vitro), which showed -in agreement with Ozolanta et al [12]-that distensibility decreases and the modulus of elasticity increases with age.…”

Fabrication of cell microintegrated blood vessel constructs through electrohydrodynamic atomization

“…The biomechanical properties of these SMC microintegrated tubes were assessed and found to be strong and flexible with compliances, stiffness, and burst strengths appropriate for blood vessel replacement. Values can be compared with those of Tajaddini et al who recently provided a thorough mechanical characterization of human coronary arteries, [30] which represent the main targets for future clinical applications of smalldiameter engineered vessels. According to those published data the microintegrated tubular constructs appear to have very similar mechanical properties to those of healthy coronary arteries (compliance = 14.1 ± 5.9 × 10 −4 mmHg, stiffness index = 16.9 ± 7.1, elastic modulus = 1.41 ± 0.72 MPa).…”