10 research outputs found
Change in Coronary Blood Flow After Percutaneous Coronary Intervention in Relation to Baseline Lesion Physiology Results of the JUSTIFY-PCI Study
Background—Percutaneous coronary intervention (PCI) aims to increase coronary blood flow by relieving epicardial obstruction. However, no study has objectively confirmed this and assessed changes in flow over different phases of the cardiac cycle. We quantified the change in resting and hyperemic flow velocity after PCI in stenoses defined physiologically by fractional flow reserve and other parameters. / Methods and Results—Seventy-five stenoses (67 patients) underwent paired flow velocity assessment before and after PCI. Flow velocity was measured over the whole cardiac cycle and the wave-free period. Mean fractional flow reserve was 0.68±0.02. Pre-PCI, hyperemic flow velocity is diminished in stenoses classed as physiologically significant compared with those classed nonsignificant (P0.80 had a significantly smaller gain (Δ4.6±2.3 cm/s; P<0.001). The change in pressure-only physiological indices demonstrated a curvilinear relationship to the change in hyperemic flow velocity but was flat for resting flow velocity. / Conclusions—Pre-PCI physiology is strongly associated with post-PCI increase in hyperemic coronary flow velocity. Hyperemic flow velocity increases 6-fold more when stenoses classed as physiologically significant undergo PCI than when nonsignificant stenoses are treated. Resting flow velocity measured over the wave-free period changes at least 4-fold less than hyperemic flow velocity after PCI
Coronary pressure and flow relationships in humans: phasic analysis of normal and pathological vessels and the implications for stenosis assessment: a report from the Iberian-Dutch-English (IDEAL) collaborators
Our understanding of human coronary physiological behaviour is derived from animal models. We sought to describe physiological behaviour across a large collection of invasive pressure and flow velocity measurements, to provide a better understanding of the relationships between these physiological parameters and to evaluate the rationale for resting stenosis assessment.Five hundred and sixty-seven simultaneous intracoronary pressure and flow velocity assessments from 301 patients were analysed for coronary flow velocity, trans-stenotic pressure gradient (TG), and microvascular resistance (MVR). Measurements were made during baseline and hyperaemic conditions. The whole cardiac cycle and the diastolic wave-free period were assessed. Stenoses were assessed according to fractional flow reserve (FFR) and quantitative coronary angiography DS%. With progressive worsening of stenoses, from unobstructed angiographic normal vessels to those with FFR ≤ 0.50, hyperaemic flow falls significantly from 45 to 19 cm/s, Ptrend 0.05 for all). Trans-stenotic pressure gradient rose with stenosis severity for both rest and hyperaemic measures (Ptrend < 0.001 for both). Microvascular resistance declines with stenosis severity under resting conditions (Ptrend < 0.001), but was unchanged at hyperaemia (2.3 ± 1.1 mmHg/cm/s; Ptrend = 0.19).With progressive stenosis severity, TG rises. However, while hyperaemic flow falls significantly, resting coronary flow is maintained by compensatory reduction of MVR, demonstrating coronary auto-regulation. These data support the translation of coronary physiological concepts derived from animals to patients with coronary artery disease and furthermore, suggest that resting pressure indices can be used to detect the haemodynamic significance of coronary artery stenoses
Diagnostic and Prognostic Implications of Coronary Flow Capacity A Comprehensive Cross-Modality Physiological Concept in Ischemic Heart Disease
OBJECTIVES The purpose of this study is to evaluate whether coronary flow capacity (CFC) improves discrimination of patients at risk for major adverse cardiac events (MACE) compared with coronary flow reserve (CFR) alone, and to study the diagnostic and prognostic implications of CFC in relation to contemporary diagnostic tests for ischemic heart disease (IHD), including fractional flow reserve (FFR). BACKGROUND Although IHD results from a combination of focal obstructive, diffuse, and microcirculatory involvement of the coronary circulation, its diagnosis remains focused on focal obstructive causes. CFC comprehensively documents flow impairment in IHD, regardless of its origin, by interpreting CFR in relation to maximal flow (hyperemic average peak flow velocity [ hAPV]), and overcomes the limitations of using CFR alone. This is governed by the understanding that ischemia occurs in vascular beds with substantially reduced hAPV and CFR, whereas ischemia is unlikely when hAPV or CFR is high. METHODS Intracoronary pressure and flow were measured in 299 vessels (228 patients), where revascularization was deferred in 154. Vessels were stratified as having normal, mildly reduced, moderately reduced, or severely reduced CFC using CFR thresholds derived from published data and corresponding hAPV percentiles. The occurrence of MACE after deferral of revascularization was recorded during 11.9 years of follow-up (quartile 1: 10.0 years, quartile 3: 13.4 years). RESULTS Combining CFR and hAPV improved the prediction of MACE over CFR alone (p = 0.01). After stratification in CFC, MACE rates throughout follow-up were strongly associated with advancing impairment of CFC (p = 0.002). After multivariate adjustment, mildly and moderately reduced CFC were associated with a 2.1-fold (95% confidence interval: 1.1 to 4.0; p = 0.017), and 7.1-fold (95% confidence interval: 2.9 to 17.1; p = 40% of vessels with normal or mildly reduced CFC still had an FFR <= 0.80. CONCLUSIONS CFC provides a cross-modality platform for the diagnosis and risk-stratification of IHD and enriches the interpretation of contemporary diagnostic tests in IHD. (C) 2015 by the American College of Cardiology Foundation
Invasive minimal Microvascular Resistance Is a New Index to Assess Microcirculatory Function Independent of Obstructive Coronary Artery Disease
Background-—Coronary microcirculatory dysfunction portends a poor cardiovascular outcome. Invasive assessment of microcirculatory dysfunction by coronary flow reserve (CFR) and hyperemic microvascular resistance (HMR) is affected by coronary artery disease (CAD). In this study we propose minimal microvascular resistance (mMR) as a new measure of microcirculatory dysfunction and aim to determine whether mMR is influenced by CAD. Methods and Results-—We obtained 482 simultaneous measurements of intracoronary Doppler flow velocity and pressure. The mMR is defined as the ratio between distal coronary pressure and flow velocity during the hyperemic wave-free period. Measurements were divided into 2 cohorts. Cohort 1 was a paired analysis involving 81 pairs with a vessel with and without CAD to investigate whether HMR, CFR, and mMR are modulated by CAD. CFR was lower, and HMR was higher, in vessels with CAD than in vessels without CAD: 2.12 0.79 versus 2.56 0.63 mm Hgcm 1 s, P<0.001, and 2.61 1.22 versus 2.31 0.89 mm Hgcm 1 s, P=0.04, respectively. mMR was equal in vessels with and without CAD: 1.54 0.77 versus 1.53 0.57 mm Hgcm 1 s, P=0.90. Differences for CFR occurred when FFR was 0.60 to 0.80 or ≤0.60 but not when FFR ≥0.80. For HMR, the difference occurred only when FFR ≤0.60. For mMR, no difference was observed in any FFR stratum. Cohort 2 was used for validation and showed significant relationships for CFR and HMR with FFR: Pearson r=0.488, P<0.001 and 0.159, P=0.03, respectively; mMR had no association with FFR: Pearson r=0.055; P=0.32. Con
Fractional Flow Reserve-Guided Percutaneous Coronary Intervention: Does Coronary Pressure Never Lie?
Chemical contamination assessment in mangrove-lined Caribbean coastal systems using the oyster Crassostrea rhizophorae as biomonitor species
This paper aims to contribute to the use of mangrove
cupped oyster, Crassostrea rhizophorae, as a biomonitor
species for chemical contamination assessment in
mangrove-lined Caribbean coastal systems. Sampling was
carried out in eight localities (three in Nicaragua and five in
Colombia) with different types and levels of contamination.
Oysters were collected during the rainy and dry seasons of
2012–2013 and the tissue concentrations of metals, polycyclic
aromatic hydrocarbons (PAHs), and persistent organic pollutants
(POPs) were determined. Low tissue concentrations of
metals (except Hg) and PAHs; moderate-to-high tissue concentrations
of Hg, hexachlorocyclohexanes (HCHs), and
dichlorodiphenyl-trichloroethanes (DDTs); detectable levels
of chlorpyrifos, polychlorinated biphenyls (PCBs) (mainly
CB28, CB118, CB138 and CB 153) and brominated diphenyl
ethers 85 (BDE85); and negligible levels of musks were recorded
in Nicaraguan oysters. A distinct profile of POPs was
identified in Colombia, where the tissue concentrations of
PCBs and synthetic musk fragrances were low to moderate,
and Ag, As, Cd, Pb, and PAHs ranged from moderate to extremely
high. Overall, the values recorded for HCHs, DDTs
and PCBs in Nicaraguan mangrove cupped oysters greatly
exceeded the reference values in tissues of C. rhizophorae
from the Wider Caribbean Region, whereas only the levels
of PCBs were occasionally surpassed in Colombia. Different
contaminant profiles were distinguished between oysters from
Nicaragua and Colombia in radar plots constructed using the
main groups of contaminants (metals, PAHs, musks, PCBs,
and organochlorine pesticides (OCPs)). Likewise, integrated
pollution indices revealed differences in the levels of contaminants.
Moreover, the profiles and levels in oyster tissues also
varied with season. Thus, principal component analysis clearly
discriminated Nicaraguan and Colombian localities and, especially
in Colombia, seasonal trends in chemical contamination
and differences amongst localities were evidenced. The geographical
and environmental disparity of the studied scenarios
may represent to a large extent the diversity of mangrove-lined
Caribbean coastal systems and therefore the present results
support the use of C. rhizophorae as suitable biomonitor species
at Caribbean regional scale, where seasonal variability
is a major factor controlling pollutant mobility and
bioavailability