The increase in minimal microvascular resistance that occurs with age may result in progressive impaired capacity of coronary vasodilation in the pan myocardial region, and may affect ischemic heart disease pathophysiology, according to a study published in JACC: Cardiovascular Interventions.
This study included 327 patients (with a total of 419 stenosed vessels), all of whom had a clinical indication for physiological examination of at least 1 intermediate angiographic severity. Assessment took place at 2 centers in the Netherlands and Spain. Measurements of intracoronary pressure and flow were performed using Doppler (n=228; 299 vessels) and thermodilution (n=99; 120 vessels). Unobstructed vessels were also measured as reference using the Doppler technique in 172 participants (75% assessed with Doppler-derived flow). Between-group differences were assessed using Kruskal-Wallis, chi-square, or 1-way analysis of variance tests, and the association between age and physiological parameters was assessed using linear regression analysis.
There were associations between increased age and reduced hyperemic flow as well as increased minimal microvascular resistance in both obstructed and unobstructed coronary arteries, indicating an aging-related decrease in coronary flow reserve (P <.001). Although no association was observed between age and epicardial stenosis location or severity, advancing age was associated with increased fractional flow reserve (R²=0.03; P =.001). Each decade of increased age was associated with a 1-6-fold increased risk for a fractional flow reserve/coronary flow reserve pattern related to concomitant diffuse or microvascular disease (high fractional flow reserve, low coronary flow reserve) and focal stenosis (95% CI, 1.1-2.3; P =.017), after adjusting for independent predictors of coronary and fractional flow reserve. Each decade of increased age was associated with a decreased risk for fractional flow reserve/coronary flow reserve pattern related to focal non-flow-limiting stenosis with normal microcirculation (low fractional flow reserve, high coronary flow reserve; relative risk, 0.7 per increase in decade; 95% CI, 0.5-1.0; P =.022).
Limitations to this study include the use of 2 techniques to assess intracoronary flow, the use of different doses and administration methods for inducing hyperemia, and of the fact that noninvasive myocardial ischemia assessments were not conducted on a routine basis.
“Aging is associated with a progressive pan-myocardial increase in minimal microvascular resistance, which leads to an impairment of coronary vasodilatory reserve,” concluded the study authors. “In patients with ischemic heart disease, such aging-related impairment in microvascular function importantly contributes to the pathophysiology of ischemic heart disease. This multilevel involvement of the coronary circulation has pertinent diagnostic and prognostic consequences but cannot be adequately identified by hyperemic coronary pressure measurements alone.”
Disclosure: Several study authors declared affiliations with the Volcano Corporation. Please see the original reference for a full list of authors’ disclosures.
van de Hoef TP, Echavarria-Pinto M, Meuwissen M, Stegehuis VE, Escaned J, Piek JJ. Contribution of age-related microvascular dysfunction to abnormal coronary: hemodynamics in patients with ischemic heart disease. 2020;13(1):20-29. JACC Cardiovasc Interv.