The blood oxygen level dependent (BOLD) effect of in-vitro myoglobin and hemoglobin

Guensch, Dominik P.; Michel, Margot; Huettenmoser, Stefan P.; Jung, Bernd; Gulac, Patrik; Segiser, Adrian; Longnus, Sarah L.; Fischer, Kady

doi:10.1038/s41598-021-90908-x

Cited by 14 publications

(15 citation statements)

References 41 publications

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“…Currently, these intriguing pathophysiologic responses are still not fully understood. Furthermore, recent research by Guensch et al has shown that myoglobin (Mb) desaturation may also play into the measured signal, although Mb desaturates later than Hb [25]. However, even a compound measure of Hb and Mb desaturation may be of importance in the characterization of PAOD as suggested by our results.…”

Section: Discussionsupporting

confidence: 60%

A Reperfusion BOLD-MRI Tissue Perfusion Protocol Reliably Differentiate Patients with Peripheral Arterial Occlusive Disease from Healthy Controls

Törngren

Eriksson

Arvidsson

et al. 2021

JCM

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There is no established technique that directly quantifies lower limb tissue perfusion. Blood oxygenation level-dependent magnetic resonance imaging (BOLD-MRI) is an MRI technique that can determine skeletal muscle perfusion. BOLD-MRI relies on magnetic differences of oxygenated and deoxygenated hemoglobin, and regional changes in oxy/deoxyhemoglobin ratio can be recorded by T2* weighted MRI sequences. We aimed to test whether BOLD-MRI can differentiate lower limb tissue perfusion in peripheral arterial occlusive disease (PAOD) patients and healthy controls. Twenty-two PAOD patients and ten healthy elderly volunteers underwent lower limb BOLD-MRI. Reactive hyperemia was provoked by transient cuff compression and images of the gastrocnemius and soleus muscles were continuously acquired at rest, during ischemia and reperfusion. Key BOLD parameters were baseline T2* absolute value and time to T2* peak value after cuff deflation (TTP). Correlations between imaging parameters and ankle-brachial index (ABI) was investigated. The mean TTP was considerably prolonged in PAOD patients compared to healthy controls (m. gastrocnemius: 111 ± 46 versus 48 ± 22 s, p = 0.000253; m. soleus: 100 ± 42 versus 41 ± 30 s, p = 0.000216). Both gastrocnemius and soleus TTP values correlated strongly with ABI (−0.82 and −0.78, p < 0.01). BOLD-MRI during reactive hyperemia differentiated most PAOD patients from healthy controls. TTP was the most decisive parameter and strongly correlated with the ABI.

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Section: Discussionsupporting

confidence: 60%

A Reperfusion BOLD-MRI Tissue Perfusion Protocol Reliably Differentiate Patients with Peripheral Arterial Occlusive Disease from Healthy Controls

Törngren

Eriksson

Arvidsson

et al. 2021

JCM

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“…This may contribute to myocardial injury after non-cardiac surgery (MINS) ( 4 ), which has been increasingly focused on over the recent years. Techniques such as oxygenation-sensitive cardiovascular magnetic resonance (OS-CMR) can non-invasively interrogate changes in myocardial oxygenation on a tissue level with high spatial resolution based on local deoxyhemoglobin fractions ( 5 , 6 ). In 2019, we reported that left ventricular myocardial oxygenation measured by OS-CMR had a curvi-linear association with mean arterial pressure ( 7 ).…”

Section: Introductionmentioning

confidence: 99%

Assessment of Myocardial Function During Blood Pressure Manipulations Using Feature Tracking Cardiovascular Magnetic Resonance

Fischer

Neuenschwander

Jung

et al. 2021

Front. Cardiovasc. Med.

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Background: Coronary autoregulation is a feedback system, which maintains near-constant myocardial blood flow over a range of mean arterial pressure (MAP). Yet in emergency or peri-operative situations, hypotensive or hypertensive episodes may quickly arise. It is not yet established how rapid blood pressure changes outside of the autoregulation zone (ARZ) impact left (LV) and right ventricular (RV) function. Using cardiovascular magnetic resonance (CMR) imaging, measurements of myocardial tissue oxygenation and ventricular systolic and diastolic function can comprehensively assess the heart throughout a range of changing blood pressures.Design and methods: In 10 anesthetized swine, MAP was varied in steps of 10–15 mmHg from 29 to 196 mmHg using phenylephrine and urapidil inside a 3-Tesla MRI scanner. At each MAP level, oxygenation-sensitive (OS) cine images along with arterial and coronary sinus blood gas samples were obtained and blood flow was measured from a surgically implanted flow probe on the left anterior descending coronary artery. Using CMR feature tracking-software, LV and RV circumferential systolic and diastolic strain parameters were measured from the myocardial oxygenation cines.Results: LV and RV peak strain are compromised both below the lower limit (LV: Δ1.2 ± 0.4%, RV: Δ4.4 ± 1.2%, p < 0.001) and above the upper limit (LV: Δ2.1 ± 0.4, RV: Δ5.4 ± 1.4, p < 0.001) of the ARZ in comparison to a baseline of 70 mmHg. LV strain demonstrates a non-linear relationship with invasive and non-invasive measures of oxygenation. Specifically for the LV at hypotensive levels below the ARZ, systolic dysfunction is related to myocardial deoxygenation (β = −0.216, p = 0.036) in OS-CMR and both systolic and diastolic dysfunction are linked to reduced coronary blood flow (peak strain: β = −0.028, p = 0.047, early diastolic strain rate: β = 0.026, p = 0.002). These relationships were not observed at hypertensive levels.Conclusion: In an animal model, biventricular function is compromised outside the coronary autoregulatory zone. Dysfunction at pressures below the lower limit is likely caused by insufficient blood flow and tissue deoxygenation. Conversely, hypertension-induced systolic and diastolic dysfunction points to high afterload as a cause. These findings from an experimental model are translatable to the clinical peri-operative environment in which myocardial deformation may have the potential to guide blood pressure management, in particular at varying individual autoregulation thresholds.

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“…6 OS-CMR exploits the signal attenuating effects of the local deoxyhemoglobin fraction as an endogenous contrast, primarily in the compartment of post-capillary myocardial venules. 6,7 A breathing maneuver consisting of a period of hyperventilation followed by a long voluntary breath-hold, triggers a vasoactive response with a myocardial oxygenation surplus. 8 An impaired response, shown by a blunted increase or even signal reduction below baseline, was shown to reflect coronary vascular dysfunction.…”

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confidence: 99%

Insights Into Myocardial Oxygenation and Cardiovascular Magnetic Resonance Tissue Biomarkers in Heart Failure With Preserved Ejection Fraction

Fischer

Guensch

Jung

et al. 2022

Circ: Heart Failure

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Background: The pathophysiology of heart failure with preserved ejection fraction is not well understood, but evidence strongly suggests involvement of microvascular dysfunction. We studied the myocardial oxygenation reserve as a direct marker of coronary vascular function and its relation to myocardial deformation and tissue characteristics by cardiovascular magnetic resonance (CMR). Methods: In a dual-center case-control study, patients with heart failure and preserved ejection fraction (>50%) and healthy controls older than 50 years underwent quantitative CMR for ventricular volumes and functional assessment with feature tracking, as well as tissue characterization (T1, T2, extracellular volume). Coronary vascular function was measured by oxygenation-sensitive (OS)–CMR of the myocardial oxygenation response to a vasoactive breathing maneuver. Results: Twenty-nine patients completed the CMR exam. Compared with cutoffs derived from 12 control subjects, circumferential peak strain was attenuated in 97% of patients. Native T1 was elevated in 93%, extracellular volume was elevated in 83%. Sixty-six percent of patients revealed either regional or global myocardial edema, defined by an increased myocardial T2. An attenuated global myocardial oxygenation reserve (<4.4%) was observed in 96% of the patients (1.7±3.9% versus 9.1±5.3% in controls, P <0.001). This was correlated with septal wall thickness (r=−0.54, P =0.003), edema (myocardial T2; β=−0.26% oxygenation-sensitive/ms [95% CI, −0.49 to −0.03], P =0.029), and reduced diastolic strain rate (β=1.50% oxygenation-sensitive/s -1 [95% CI, 0.06–2.90], P =0.042). Conclusions: In patients with clinical heart failure with preserved ejection fraction, vascular dysfunction as measured by an attenuated myocardial oxygenation reserve is associated with myocardial edema, a thicker septum, and diastolic dysfunction. A quantitative comprehensive CMR exam including oxygenation-sensitive–CMR allows for comprehensive imaging-based phenotyping of heart failure with preserved ejection fraction.

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The blood oxygen level dependent (BOLD) effect of in-vitro myoglobin and hemoglobin

Cited by 14 publications

References 41 publications

A Reperfusion BOLD-MRI Tissue Perfusion Protocol Reliably Differentiate Patients with Peripheral Arterial Occlusive Disease from Healthy Controls

A Reperfusion BOLD-MRI Tissue Perfusion Protocol Reliably Differentiate Patients with Peripheral Arterial Occlusive Disease from Healthy Controls

Assessment of Myocardial Function During Blood Pressure Manipulations Using Feature Tracking Cardiovascular Magnetic Resonance

Insights Into Myocardial Oxygenation and Cardiovascular Magnetic Resonance Tissue Biomarkers in Heart Failure With Preserved Ejection Fraction

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