Abstract 16131: Novel Magnetic Resonance Wave Intensity Analysis in Pulmonary Hypertension

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Michael A Quail ◽  
Daniel S Knight ◽  
Jennifer A Steeden ◽  
Liesbeth Taelman ◽  
Shahin Moledina ◽  
...  
Keyword(s):  
Pulmonary Hypertension ◽  
Pulmonary Arteries ◽  
Wave Intensity ◽  
Healthy Controls ◽  
Intensity Analysis ◽  
Wave Intensity Analysis ◽  
Resonance Wave ◽  
Golden Angle ◽  
Significant Difference ◽  
Pressure And Velocity Measurements

Background: Pathological pulmonary wave reflections (WR) are a potential hemodynamic biomarker for pulmonary hypertension (PH). WR can be quantified using wave intensity analysis (WIA), typically utilizing simultaneous invasive pressure and velocity measurements. In this study we reformulated WIA to use CMR area and flow to measure reflections non-invasively. We hypothesized that this method could detect differences in WR in PH patients compared to healthy controls and could also differentiate certain PH subtypes. Methods: 20 patients with PH (35% CTEPH), mean age 54years (75% female) and 10 healthy controls, 47years (60% female) were recruited. Branch pulmonary artery (PA) flow volume (Q) and area curves (A) were used to measure wave intensity ( dI ), defined as, dI =[[Unable to Display Character: &#8710;]]Ax[[Unable to Display Character: &#8710;]]Q and dI ± =± c /4 [[[Unable to Display Character: &#8710;]]A± [[Unable to Display Character: &#8710;]]Q/ c ] 2 , where c =wave-speed. Data were acquired using a retrospectively gated, respiratory navigated, golden-angle, 10.5ms temporal resolution, phase-contrast MR sequence. All patients also underwent right heart cardiac catheterization for pressure and vascular resistance (PVR) measurement, median interval 6 days (IQR 2-11days). The presence of proximal clot in CTEPH patients was determined from contemporaneous CT/angiographic data. Results: A backwards-travelling compression wave (BCW) was present in both left and right PAs of all PH patients, but was absent in all controls ( p =6e -8 ). A backwards-travelling expansion/suction wave was present in the 19/20 branch PAs of controls, and only 4/40 PAs in patients ( p < 0.0001). The area under the BCW was associated with a sensitivity of 100% (95% CI 63-100%) and specificity of 91% (95% CI 75-98%) for the presence of clot in the proximal pulmonary arteries of patients with CTEPH. Conclusions: Noninvasive pulmonary WIA accurately delineates pulmonary vascular health and disease. The main findings of this study were: i) There was a significant difference in WIA metrics between patients and controls, in particular, the presence of a BCW was specifically associated with the presence of PH; and ii) The magnitude of the BCW area showed discriminatory capacity for the presence of proximal PA clot in patients with CTEPH. We believe that these results demonstrate that WIA could be used in the non-invasive assessment of PH.

scholarly journals Noninvasive pulmonary artery wave intensity analysis in pulmonary hypertension

2015 ◽  
Vol 308 (12) ◽  
pp. H1603-H1611 ◽  
Author(s):  
Michael A. Quail ◽  
Daniel S. Knight ◽  
Jennifer A. Steeden ◽  
Liesbeth Taelman ◽  
Shahin Moledina ◽  
...  
Keyword(s):  
Pulmonary Hypertension ◽  
Pulmonary Artery ◽  
Left Pulmonary Artery ◽  
Wave Intensity ◽  
Healthy Controls ◽  
Intensity Analysis ◽  
Wave Intensity Analysis ◽  
Pulmonary Vessel ◽  
Golden Angle ◽  
Angiographic Data

Pulmonary wave reflections are a potential hemodynamic biomarker for pulmonary hypertension (PH) and can be analyzed using wave intensity analysis (WIA). In this study we used pulmonary vessel area and flow obtained using cardiac magnetic resonance (CMR) to implement WIA noninvasively. We hypothesized that this method could detect differences in reflections in PH patients compared with healthy controls and could also differentiate certain PH subtypes. Twenty patients with PH (35% CTEPH and 75% female) and 10 healthy controls (60% female) were recruited. Right and left pulmonary artery (LPA and RPA) flow and area curves were acquired using self-gated golden-angle, spiral, phase-contrast CMR with a 10.5-ms temporal resolution. These data were used to perform WIA on patients and controls. The presence of a proximal clot in CTEPH patients was determined from contemporaneous computed tomography/angiographic data. A backwards-traveling compression wave (BCW) was present in both LPA and RPA of all PH patients but was absent in all controls ( P = 6e−8). The area under the BCW was associated with a sensitivity of 100% [95% confidence interval (CI) 63–100%] and specificity of 91% (95% CI 75–98%) for the presence of a clot in the proximal PAs of patients with CTEPH. In conclusion, WIA metrics were significantly different between patients and controls; in particular, the presence of an early BCW was specifically associated with PH. The magnitude of the area under the BCW showed discriminatory capacity for the presence of proximal PA clot in patients with CTEPH. We believe that these results demonstrate that WIA could be used in the noninvasive assessment of PH.

scholarly journals Novel magnetic resonance wave intensity analysis in pulmonary hypertension

2014 ◽  
Vol 16 (S1) ◽  
Author(s):  
Michael A Quail ◽  
Daniel S Knight ◽  
Jennifer A Steeden ◽  
Andrew Taylor ◽  
Vivek Muthurangu
Keyword(s):  
Pulmonary Hypertension ◽  
Magnetic Resonance ◽  
Wave Intensity ◽  
Intensity Analysis ◽  
Wave Intensity Analysis ◽  
Resonance Wave

scholarly journals Feasibility of Wave Intensity Analysis in Patients With Conotruncal Anomalies Before and After Pregnancy: New Physiological Insights?

2021 ◽  
Vol 8 ◽  
Author(s):  
Maria Victoria Ordonez ◽  
Sandra Neumann ◽  
Massimo Caputo ◽  
Stephanie Curtis ◽  
Giovanni Biglino
Keyword(s):  
Pulmonary Regurgitation ◽  
Aortic Distensibility ◽  
Double Outlet Right Ventricle ◽  
Wave Intensity ◽  
Intensity Analysis ◽  
Wave Intensity Analysis ◽  
Significant Difference ◽  
Before And After ◽  
Conotruncal Anomalies

Background: Conotruncal anomalies (CTA) are associated with ongoing dilation of the aortic root, as well as increased aortic stiffness, which may relate to intrinsic properties of the aorta. Pregnancy hormones lead to hemodynamic changes and remodeling of the tunica media, resulting in the opposite effect, i.e., increasing distensibility. These changes normalize post-pregnancy in healthy women but have not been fully investigated in CTA patients.Methods: We examined aortic distensibility and ventriculo-arterial coupling before and after pregnancy using cardiovascular magnetic resonance (CMR)-derived wave intensity analysis (WIA). Pre- and post-pregnancy CMR data were retrospectively analyzed. Aortic diameters were measured before, during, and after pregnancy by cardiac ultrasound and before and after pregnancy by CMR. Phase contrast MR flow sequences were used for calculating wave speed (c) and intensity (WI). A matched analysis was performed comparing results before and after pregnancy.Results: Thirteen women (n = 5, transposition of the great arteries; n = 6, tetralogy of Fallot; n = 1, double outlet right ventricle, n = 1, truncus arteriosus) had 19 pregnancies. Median time between delivery and second CMR was 2.3 years (range: 1–6 years). The aortic diameter increased significantly after pregnancy in nine (n = 9) patients by a median of 4 ± 2.3 mm (range: 2–7.0 mm, p = 0.01). There was no difference in c pre-/post-pregnancy (p = 0.73), suggesting that increased compliance, typically observed during pregnancy, does not persist long term. A significant inverse relationship was observed between c and heart rate (HR) after pregnancy (p = 0.01, r = 0.73). There was no significant difference in cardiac output, aortic/pulmonary regurgitation, or WI peaks pre-/post-pregnancy.Conclusions: WIA is feasible in this population and could provide physiological insights in larger cohorts. Aortic distensibility and wave intensity did not change before and after pregnancy in CTA patients, despite an increase in diameter, suggesting that pregnancy did not adversely affect coupling in the long-term.

3.4 WAVE INTENSITY ANALYSIS PROVIDES NOVEL INSIGHTS INTO PULMONARY HYPERTENSION

2016 ◽  
Vol 16 (C) ◽  
pp. 51
Author(s):  
Junjing Su ◽  
Charlotte Manisty ◽  
Kim H. Parker ◽  
Soren Mellemkjaer ◽  
Luke Howard ◽  
...  
Keyword(s):  
Pulmonary Hypertension ◽  
Wave Intensity ◽  
Intensity Analysis ◽  
Wave Intensity Analysis

Minor impact of constraint from perivascular flow probes on wave intensity analysis

2020 ◽  
Vol 234 (11) ◽  
pp. 1277-1287 ◽  
Author(s):  
Jonathan P Mynard ◽  
Joseph J Smolich
Keyword(s):  
Compression Wave ◽  
Pulmonary Arteries ◽  
Wave Intensity ◽  
Minor Effect ◽  
Apparent Velocity ◽  
Intensity Analysis ◽  
Wave Intensity Analysis ◽  
Flow Probe ◽  
Adult Sheep ◽  
Wide Range

Perivascular flow probes are considered the gold-standard for measuring volumetric blood flow in animal studies. Although flow probes are generally placed non-constrictively around the vessel of interest, pressure-elevating interventions performed during an experiment may lead to vessel expansion and some probe-vessel impingement, particularly in highly compliant vessels such as adult sheep aorta or major pulmonary arteries in fetus lambs. This study assessed to what extent such mild flow probe constraint may impact on wave intensity analysis. We also investigated whether errors arising from flow probe constraint could explain apparent pressure reflection indices ( Rp > 1) that have been observed in fetus lamb pulmonary arteries under some experimental conditions. These questions were investigated with one-dimensional models of an adult sheep aorta and fetus lamb pulmonary artery, with a virtual flow probe incorporated as a non-linear external constraint term in the vessel constitutive equation. Model-derived flow and pressure were subjected to standard analysis procedures that would be applied experimentally (correcting for apparent velocity lags and calculating wave speed via the PU-loop method). For the adult sheep model, simulations covering a wide range of haemodynamic conditions revealed a mostly minor effect (<10%) of probe constraint on the intensity and pressure effects of the three major waves (forward compression wave, forward decompression wave, backward compression wave). Moreover, flow probe constraint had essentially no impact on Rp in the fetus lamb model, suggesting that such constraint is unlikely to be responsible for an observed Rp > 1. Mild flow probe constraint is likely to have little impact on wave intensity analysis.

scholarly journals Estimation of coronary wave intensity analysis using noninvasive techniques and its application to exercise physiology

2016 ◽  
Vol 310 (5) ◽  
pp. H619-H627 ◽  
Author(s):  
Christopher J. Broyd ◽  
Sukhjinder Nijjer ◽  
Sayan Sen ◽  
Ricardo Petraco ◽  
Siana Jones ◽  
...  
Keyword(s):  
Coronary Circulation ◽  
Exercise Physiology ◽  
Left Ventricular ◽  
Wave Intensity ◽  
Concordance Correlation Coefficient ◽  
Intensity Analysis ◽  
Wave Intensity Analysis ◽  
Concordance Correlation ◽  
Decompression Wave ◽  
Pulsed Wave Doppler

Wave intensity analysis (WIA) has found particular applicability in the coronary circulation where it can quantify traveling waves that accelerate and decelerate blood flow. The most important wave for the regulation of flow is the backward-traveling decompression wave (BDW). Coronary WIA has hitherto always been calculated from invasive measures of pressure and flow. However, recently it has become feasible to obtain estimates of these waveforms noninvasively. In this study we set out to assess the agreement between invasive and noninvasive coronary WIA at rest and measure the effect of exercise. Twenty-two patients (mean age 60) with unobstructed coronaries underwent invasive WIA in the left anterior descending artery (LAD). Immediately afterwards, noninvasive LAD flow and pressure were recorded and WIA calculated from pulsed-wave Doppler coronary flow velocity and central blood pressure waveforms measured using a cuff-based technique. Nine of these patients underwent noninvasive coronary WIA assessment during exercise. A pattern of six waves were observed in both modalities. The BDW was similar between invasive and noninvasive measures [peak: 14.9 ± 7.8 vs. −13.8 ± 7.1 × 104 W·m−2·s−2, concordance correlation coefficient (CCC): 0.73, P < 0.01; cumulative: −64.4 ± 32.8 vs. −59.4 ± 34.2 × 102 W·m−2·s−1, CCC: 0.66, P < 0.01], but smaller waves were underestimated noninvasively. Increased left ventricular mass correlated with a decreased noninvasive BDW fraction ( r = −0.48, P = 0.02). Exercise increased the BDW: at maximum exercise peak BDW was −47.0 ± 29.5 × 104 W·m−2·s−2 ( P < 0.01 vs. rest) and cumulative BDW −19.2 ± 12.6 × 103 W·m−2·s−1 ( P < 0.01 vs. rest). The BDW can be measured noninvasively with acceptable reliably potentially simplifying assessments and increasing the applicability of coronary WIA.

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