Doppler Versus Thermodilution-Derived Coronary Microvascular Resistance to Predict Coronary Microvascular Dysfunction in Patients with Acute Myocardial Infarction or Stable Angina Pectoris

Coronary microvascular resistance is increasingly measured as a predictor of clinical outcomes, but there is no accepted gold-standard measurement. We compared the diagnostic accuracy of two invasive indices of microvascular resistance, Doppler-derived hyperemic microvascular resistance (hMR) and thermodilution-derived index of microcirculatory resistance (IMR), at predicting microvascular dysfunction. 54 patients (61±10 years) undergoing cardiac catheterization, for stable coronary artery disease (n=10) or acute myocardial infarction (AMI, n=44), had simultaneous intracoronary pressure, Doppler flow velocity and thermodilution flow data acquired from 74 unobstructed vessels, at rest and hyperemia. Three independent measures of microvascular function were assessed, using predefined dichotomous thresholds: i) CFR, the average value of Doppler- and thermodilution-derived coronary flow reserve (CFR), and cardiovascular magnetic resonance derived: ii) Myocardial Perfusion Reserve Index (MPRI) and iii) Microvascular Obstruction (MVO). hMR correlated with IMR (rho = 0.41, p<0.0001). hMR had better diagnostic accuracy than IMR to predict CFR (area under curve, (AUC) 0.82 versus 0.58, p<0.001, sensitivity/specificity 77/77% versus 51/71%) and MPRI (AUC 0.85 versus 0.72, p=0.19, sensitivity/specificity 82/80% versus 64/75%). In AMI patients, the AUCs of hMR and IMR at predicting extensive MVO were 0.83 and 0.72 respectively (p=0.22, sensitivity/specificity 78/74% versus 44/91%). We measured two invasive indices of coronary microvascular resistance to predict multiple distinct measures of microvascular dysfunction. We found these two invasive indices only correlate modestly and so cannot be considered equivalent. In our study, the correlation between independent invasive and non-invasive measures of microvascular function was better with hMR than with IMR

Downstream Influence of Coronary Stenoses on Microcirculatory Remodeling A Histopathology Study

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Changes in Coronary Blood Flow After Acute Myocardial Infarction Insights From a Patient Study and an Experimental Porcine Model

The aim of this study was to determine the effects of an acute myocardial infarction (AMI) on baseline and hyperemic flow in both culprit and nonculprit arteries. An impaired coronary flow reserve (CFR) after AMI is related to worse outcomes. The individual contribution of resting and hyperemic flow to the reduction of CFR is unknown. Furthermore, it is unclear whether currently used experimental models of AMI resemble the clinical situation with respect to coronary flow parameters. Intracoronary Doppler flow velocity measurements were obtained in culprit and nonculprit arteries immediately after successfully revascularized ST-segment elevation myocardial infarction (n = 40). Stable patients without obstructive coronary artery disease served as control subjects and were selected by propensity-score matching (n = 40). Similar measurements in an AMI porcine model were taken both before and immediately after 75-min balloon occlusion of the left circumflex artery (n = 11). In the culprit artery, CFR was 36% lower than in matched control subjects (Δ = -0.9; 1.8 ± 0.9 vs. 2.8 ± 0.7; p < 0.001) with consistent observations in swine (Δ = -0.9; 1.5 ± 0.4 vs. 2.4 ± 0.9 for after and before AMI, respectively; p = 0.04). An increased baseline and a decreased hyperemic flow contributed to the reduction in CFR in both patients (baseline flow: Δ = +5 and hyperemic flow: Δ = -7 cm/s) and swine (baseline flow: Δ = +8 and hyperemic flow: Δ = -6 cm/s). Similar changes were observed in nonculprit arteries (CFR: 2.8 ± 0.7 vs. 2.0 ± 0.7 for STEMI patients and control subjects; p < 0.001). CFR significantly correlated with infarct size as a percentage of the left ventricle in both patients (r = -0.48; p = 0.001) and swine (r = -0.61; p = 0.047). CFR in both culprit and nonculprit coronary arteries decreases after AMI with contributions from both an increased baseline flow and a decreased hyperemic flow. The decreased CFR after AMI in culprit and nonculprit vessels is not a result of pre-existing microvascular dysfunction, but represents a combination of post-occlusive hyperemia, myocardial necrosis, hemorrhagic microvascular injury, compensatory hyperkinesis, and neurohumoral vasoconstrictio

Vier scenario’s voor de inrichting van Nederland in 2050 : Ruimtelijke Verkenning 2023

In de Ruimtelijke Verkenning 2023 heeft het PBL scenario’s ontwikkeld voor de inrichting van Nederland in 2050. In dit hoofdrapport worden vier mogelijke ruimtelijke toekomsten gepresenteerd. Dat zijn: Mondiaal Ondernemend (een toekomstscenario waarin grote bedrijven de lead hebben), Snelle Wereld (de nog verder toegenomen digitalisering doet afstanden verdwijnen), Groen Land (veel ruimte voor de natuur) en Regionaal Geworteld (burgers nemen het initiatief in hun eigen leefomgeving). Voor elk scenario zijn op basis van ruimtelijke modellering en ontwerpend onderzoek gedetailleerde kaarten van het bijbehorende Nederland van 2050 gemaakt. Deze scenariokaarten brengen in beeld welke gevolgen verschillende keuzes hebben