scholarly journals Impaired Pulmonary Vascular Adaptation to Exercise in Emphysema without Pulmonary Hypertension – A Proof-of-Concept Study

2021 ◽  
Author(s):  
Thibaut Capron ◽  
Axel Bartoli ◽  
Stanislas Rappacchi ◽  
Clarisse Gautier ◽  
Faiza Bettayeb ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Pulmonary Hypertension ◽  
Cardiac Output ◽  
Magnetic Resonance ◽  
Bronchial Obstruction ◽  
Resonance Imaging ◽  
Pulmonary Hemodynamics ◽  
Ventricular Ejection Fraction ◽  
Vascular Adaptation ◽  
Adaptation To Exercise

Abstract Background: Chronic obstructive pulmonary disease with emphysema lead to respiratory disability beyond bronchial obstruction. The functional impact of pulmonary vascular lesions in emphysema remains unknown. We investigated pulmonary vascular adaptation to exercise in patients with extended emphysema.Methods: Chest magnetic resonance imaging was used to quantitatively assess right-heart function, pulmonary artery and distal pulmonary blood flow. This was performed at rest and during cycling exercise with a magnetic resonance imaging-compatible cyclo-ergometer. Seven emphysematous patients without pulmonary hypertension were compared to 7 healthy non-smokers matched in gender and age.Results: At rest, cardio-pulmonary hemodynamics and distal pulmonary vascular parameters were similar in both groups. Intrasubject adaptation to exercise in emphysematous patients was characterized by a higher increase in right-ventricular ejection fraction (ΔRVEF +8.1 vs. -2.4 %, P=0.046) though a lower right-cardiac output (4.41 vs. 5.79 L/min, P=0.04) at exercise. Accounting for right-cardiac output variation, the distal pulmonary vascular yield index trended to be decreased in patients (ΔPBF/ΔQf -0.78 vs. +18.83 %, P=0.18).Conclusions: Pulmonary vascular adaptation to exercise is impaired in emphysematous patients without identified pulmonary hypertension.Clinical trial registration NCT 04126616.

scholarly journals Quantification of Cardiac Output with Phase Contrast Magnetic Resonance Imaging in Patients with Pulmonary Hypertension

2020 ◽  
Vol 10 ◽  
pp. 26
Author(s):  
Jose Ricardo Po ◽  
Matthew Tong ◽  
Talha Meeran ◽  
Alekhya Potluri ◽  
Amresh Raina ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Pulmonary Hypertension ◽  
Cardiac Output ◽  
Cardiac Magnetic Resonance ◽  
Magnetic Resonance ◽  
Phase Contrast ◽  
Right Heart Catheterization ◽  
Heart Catheterization ◽  
Resonance Imaging ◽  
Invasive Measurement

Objective: The purpose of the study is to compare phase contrast (PC) imaging with invasive measurements of cardiac output (CO) in patients with pulmonary hypertension (PH). Materials and Methods: We analyzed 81 cases with PH who underwent cardiac magnetic resonance imaging and right heart catheterization (RHC). Measurement of CO and stroke volume (SV) by cardiac magnetic resonance (CMR) was performed by PC imaging of the proximal aorta (Ao) and pulmonary artery (Pa) and by RHC using the Fick and thermodilution (TD) methods. Results: There was good correlation in CO measurements between PC and RHC; however, there was better correlation with SV measurements; Fick-TD (r=0.85), PC-TD (Ao r=0.77, Pa r=0.79), and PC-Fick (Ao r = 0.73, Pa r = 0.78). Bland-Altman analysis of SV showed that Pa PC had slightly lower standard deviation than Ao PC; PC-Fick (Pa SD = 15.11 vs. Ao SD = 16.4 ml) and PC-TD (Pa SD = 16.99 ml vs. Ao SD = 17.4 ml) while Fick-TD had the lowest (SD = 14.4 ml). Compared to Fick, measurement of SV with Ao PC (‒4.12 ml) and Pa PC (0.22 ml) both had lower mean difference than TD (‒11.1 ml). Conclusion: Non-invasive measurement of CO and SV using PC-CMR correlates well with invasive measurement using RHC. Our study showed that PC-CMR had high accuracy and precision when compared to Fick. Among all the modalities, PC-CMR contributed the least amount of variation in measurements.

Abstract 11636: Right Ventricle Lymphatic Vessel Insufficiency Contributes to Interstitial Fluid Stasis, Inflammation, Fibrosis, and Failure in Pulmonary Hypertension

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Kelley L Colvin ◽  
Ozus Lohani ◽  
Sarah M Williams ◽  
D D Ivy ◽  
Kurt R Stenmark ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Pulmonary Hypertension ◽  
Cardiac Output ◽  
Magnetic Resonance ◽  
Pericardial Effusion ◽  
Connexin 43 ◽  
Lymphatic Vessels ◽  
Cell Junctions ◽  
Cell Junction ◽  
Resonance Imaging

Introduction: Pulmonary hypertension (PH) is characterized by cardiopulmonary remodeling. The ensuing right ventricular (RV) hypertrophy and failure contribute to significant mortality. Pericardial effusion worsens the prognosis for PH patients, yet no mechanistic data are available. Hypothesis: We hypothesized that lymphatic vessels in rat models of PH would be decreased and dysfunctional compared to controls. Methods: We used the Sugen 5416-hypoxia (Su-Hx) and monocrotaline (MCT) models of PH. To assess the degree of cardiac lymphatic vascularity, identify cell types, and to evaluate cell junction complexes in PH rats vs. controls, we used flow cytomtery, qPCR, immunofluorescence, and immunoblot. To assess myocardial edema, we used wet-to-dry weight ratios, echocardiography, and magnetic resonance imaging (MRI). In patients, we used echocardiography and magnetic resonance imaging to quantify RV edema and pericardial effusion. Results: We found that the presence of pericardial effusion by either MRI or echocardiography correlated with lower cardiac output in patients with PH (n =6). We found decreased lymphatics in RVs of rats with PH due to either Su-Hx or MCT, compared to controls (n= 5 per group). In the heart, AQP-1+/vWF-/KDR- lymphatic vessels co-expressed podoplanin and were distributed throughout the RV in controls and much less so in PH rats. Lymphatics appeared unchanged in size or number in the left ventricle of all rats. We found increases in myocardial fluid in RVs of PH rats vs. controls, which correlated positively with fibrosis and negatively to cardiac output. The presence of excess myocardial fluid coincided with collagen deposition but without increases in CD68, CD11b, CD11c, or CD163 macrophage infiltration. We observed disturbed connexin-43 and claudin-5 junctional complexes around alpha-actinin+ myocytes and TCF21+ cardiac fibroblasts in PH RVs compared to controls. Conclusions: In severe PH, RV function is likely impaired by insufficient lymphatic-mediated fluid clearance and the presence of dysfunctional cell junctions. A clearer understanding of how the cardiac lymphatic system impacts the pathobiology of PH may lead to novel therapy.

scholarly journals Safety aspects of the PiCCO thermodilution-cardiac output catheter during magnetic resonance imaging at 3 Tesla

2021 ◽  
Author(s):  
Marieke Voet ◽  
Christiaan G. Overduin ◽  
Ernst L. Stille ◽  
Jurgen J. Fütterer ◽  
Joris Lemson
Keyword(s):  
Magnetic Resonance Imaging ◽  
Cardiac Output ◽  
Magnetic Resonance ◽  
Critically Ill ◽  
Cardiac Output Monitoring ◽  
Measured Temperature ◽  
Resonance Imaging ◽  
Worst Case ◽  
Thermodilution Cardiac Output ◽  
3T Mri

AbstractThermodilution cardiac output monitoring, using a thermistor-tipped intravascular catheter, is used in critically ill patients to guide hemodynamic therapy. Often, these patients also need magnetic resonance imaging (MRI) for diagnostic or prognostic reasons. As thermodilution catheters contain metal, they are considered MRI-unsafe and advised to be removed prior to investigation. However, removal and replacement of the catheter carries risks of bleeding, perforation and infection. This research is an in vitro safety assessment of the PiCCO™ thermodilution catheter during 3 T Magnetic Resonance Imaging (3T-MRI).  In a 3T-MRI environment, three different PiCCO™ catheter sizes were investigated in an agarose-gel, tissue mimicking phantom. Two temperature probes measured radiofrequency-induced heating; one at the catheter tip and one at a reference point. Magnetically induced catheter dislocation was assessed by visual observation as well as by analysis of the tomographic images. For all tested catheters, the highest measured temperature increase was 0.2 °C at the center of the bore and 0.3 °C under “worst-case” setting for the tested MRI pulse sequences. No magnetically induced catheter displacements were observed. Under the tested circumstances, no heating or dislocation of the PiCCO™ catheter was observed in a tissue mimicking phantom during 3T-MRI. Leaving the catheter in the critically ill patient during MRI investigation might pose a lower risk of complications than catheter removal and replacement.

Nitrate induced vasoplegia depletes cardiac energy reserves: a model for acute cardiomyopathy in septic shock?

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
W Watson ◽  
P.G Green ◽  
M.K Burrage ◽  
R.R Chamley ◽  
A.J Lewis ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Heart Rate ◽  
Septic Shock ◽  
Creatine Kinase ◽  
Cardiac Output ◽  
Magnetic Resonance ◽  
Resonance Spectroscopy ◽  
Funding Source ◽  
Resonance Imaging ◽  
Cardiac Volumes

Abstract Introduction The healthy heart is at its most efficient when contractile filaments are stretched with preload. To produce the same cardiac output, oxygen requirement rises are proportionally greater with increased inotropy or heart rate than with increased preload. We hypothesized that in vasoplegia, loss of preload (owing to dilation of capacitance veins) and compensatory rises in heart rate and contractility would compromise the efficiency of the heart. We speculated that this may be one factor impairing cardiac function in conditions of distributive shock such as sepsis and looked to model the effects. We used cardiac magnetic resonance imaging to capture changes in cardiac volumes and contractility and magnetic resonance spectroscopy to investigate changes in ATP metabolism within the myocardium in healthy volunteers given GTN as a vasodilator. Methods We recruited 7 healthy volunteers (mean age 40 years, range 28–62 years; mean BMI 21.9, range 18.5–24.5) and measured their baseline cardiac volumes and function, PCr/ATP ratio and Creatine Kinase first order rate constant (CKkf), using cardiac magnetic resonance imaging and magnetic resonance spectroscopy and saturation transfer at 3 Tesla. At the same visit, they received a glyceryl trinitrate (GTN) infusion to induce vasoplegia and the measurements were repeated. We targeted GTN infusion rate to a fall in mean arterial pressure of 15mmHg. Results The GTN infusion brought about a fall in mean arterial pressure (from a baseline of 79±7mmHg to 64±7 mmHg, p<0.0001) and a fall in LV end diastolic volume (169±57 ml vs 148±58 ml, p=0.003) indicating a reduction in preload. As expected, there was a compensatory rise in heart rate (61±7 bpm vs 69±10bpm, p=0.0005) and ejection fraction (62±3% vs 67±3%, p=0.001), however cardiac output remained unchanged (6.72±1.49 L/min vs 6.68±1.48 L/min, p=0.87). Cardiac work (calculated as stroke volume x MAP x heart rate) fell (477±123 vs 424±119 L.mmHg/min, p=0.03). There was a fall in PCr/ATP ratio on GTN (2.18±0.25 vs 1.91±0.2, p 0.03) while CKkf more than doubled (0.14±0.06 s-1 vs 0.23±0.08 s-1, p=0.02) and creatine kinase flux also showed a significant increase (1.65±0.78 μmol/g/s vs 2.28±0.71 μmol/g/s, p=0.05). Conclusions What is novel here is that we show a fall in PCr/ATP ratio: as ATP concentrations in the cell are strictly maintained, this suggests phosphocreatine pool depletion occurs when preload is lost and cardiac output is maintained by an increase in inotropy and chronotropy. The rise in CKkf and CK flux confirm the increased energy demand. Progressive energetic depletion during high demand may give rise to contractile dysfunction over time as the heart is unable to keep up with increased requirements for ATP, and progressively becomes more starved of energy. This could be a mechanism of cardiac dysfunction in septic shock and other vasoplegic states. Figure 1 Funding Acknowledgement Type of funding source: Foundation. Main funding source(s): British Heart Foundation

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