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Surrogates for myocardial power and power efficiency in patients with aortic valve disease.

ABSTRACT: We aimed to assess surrogate markers for left ventricular (LV) myocardial power and efficiency in patients with isolated aortic stenosis (AS) and combined stenosis/regurgitation (AS/AR). In AS (n?=?59), AS/AR (n?=?21) and controls (n?=?14), surrogates for LV myocardial power and circulatory/external myocardial efficiency were obtained from cardiac MRI. Median surrogate LV myocardial power was increased in AS, 7.7?W/m2 (interquartile range 6.0-10.2; p?=?0.010) and AS/AR, 10.8?W/m2 (8.9-13.4; p?

SUBMITTER: Lee CB

PROVIDER: S-EPMC6848480 | biostudies-literature | 2019 Nov

REPOSITORIES: biostudies-literature

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Surrogates for myocardial power and power efficiency in patients with aortic valve disease.

Lee Chong-Bin CB Goubergrits Leonid L Fernandes Joao Filipe JF Nordmeyer Sarah S Knosalla Christoph C Berger Felix F Falk Volkmar V Kuehne Titus T Kelm Marcus M

Scientific reports 20191111 1

We aimed to assess surrogate markers for left ventricular (LV) myocardial power and efficiency in patients with isolated aortic stenosis (AS) and combined stenosis/regurgitation (AS/AR). In AS (n = 59), AS/AR (n = 21) and controls (n = 14), surrogates for LV myocardial power and circulatory/external myocardial efficiency were obtained from cardiac MRI. Median surrogate LV myocardial power was increased in AS, 7.7 W/m<sup>2</sup> (interquartile range 6.0-10.2; p = 0.010) and AS/AR, 10.8 W/m<sup>2 ...[more]

PMID: 31712631

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Project description:BackgroundMyocardial oxygen consumption (MVO2) and its coupling to contractile work are fundamentals of cardiac function and may be involved causally in the transition from compensated left ventricular hypertrophy to failure. Nevertheless, these processes have not been studied previously in patients with aortic valve stenosis (AS).Methods and resultsParticipants underwent 11C-acetate positron emission tomography, cardiovascular magnetic resonance, and echocardiography to measure MVO2 and myocardial external efficiency (MEE) defined as the ratio of left ventricular stroke work and the energy equivalent of MVO2. We studied 10 healthy controls (group A), 37 asymptomatic AS patients with left ventricular ejection fraction ?50% (group B), 12 symptomatic AS patients with left ventricular ejection fraction ?50% (group C), and 9 symptomatic AS patients with left ventricular ejection fraction <50% (group D). MVO2 did not differ among groups A, B, C, and D (0.105±0.02, 0.117±0.024, 0.129±0.032, and 0.104±0.026 mL/min per gram, respectively; P=0.07), whereas MEE was reduced in group D (21.0±1.6%, 22.3±3.3%, 22.1±4.2%, and 17.3±4.7%, respectively; P<0.05). Similarly, patients with global longitudinal strain greater than -12% and paradoxical low-flow, low-gradient AS had impaired MEE (P<0.05 versus controls). The ability to discriminate between symptomatic and asymptomatic patients was superior for global longitudinal strain compared with MVO2 and MEE (area under the curve 0.98, 0.48, and 0.61, respectively; P<0.05).ConclusionsAS patients display a persistent ability to maintain normal MVO2 and MEE (ie, the ability to convert energy into stroke work); however, patients with left ventricular ejection fraction <50%; global longitudinal strain greater than -12%; or paradoxical low-flow, low-gradient AS demonstrate reduced MEE. These findings suggest that mitochondrial uncoupling contributes to the dismal prognosis in patients with reduced contractile function or paradoxical low-flow, low-gradient AS.

Project description:BackgroundCirculatory efficiency reflects the ratio between total left ventricular work and the work required for maintaining cardiovascular circulation. The effect of severe aortic valve stenosis (AS) and aortic valve replacement (AVR) on left ventricular/circulatory mechanical power and efficiency is not yet fully understood. We aimed to quantify left ventricular (LV) efficiency in patients with severe AS before and after surgical AVR.MethodsCirculatory efficiency was computed from cardiovascular magnetic resonance (CMR) imaging derived volumetric data, echocardiographic and clinical data in patients with severe AS (n?=?41) before and 4 months after AVR and in age and sex-matched healthy subjects (n?=?10).ResultsIn patients with AS circulatory efficiency was significantly decreased compared to healthy subjects (9?±?3% vs 12?±?2%; p?=?0.004). There were significant negative correlations between circulatory efficiency and LV myocardial mass (r?=?-?0.591, p?<?0.001), myocardial fibrosis volume (r?=?-?0.427, p?=?0.015), end systolic volume (r?=?-?0.609, p?<?0.001) and NT-proBNP (r?=?-?0.444, p?=?0.009) and significant positive correlation between circulatory efficiency and LV ejection fraction (r?=?0.704, p?<?0.001). After AVR, circulatory efficiency increased significantly in the total cohort (9?±?3 vs 13?±?5%; p?<?0.001). However, in 10/41 (24%) patients, circulatory efficiency remained below 10% after AVR and, thus, did not restore to normal values. These patients also showed less reduction in myocardial fibrosis volume compared to patients with restored circulatory efficiency after AVR.ConclusionIn our cohort, circulatory efficiency is reduced in patients with severe AS. In 76% of cases, AVR leads to normalization of circulatory efficiency. However, in 24% of patients, circulatory efficiency remained below normal values even after successful AVR. In these patients also less regression of myocardial fibrosis volume was seen. Trial Registration clinicaltrials.gov NCT03172338, June 1, 2017, retrospectively registered.

Project description:BACKGROUND:Left ventricular (LV) hypertrophy, a key process in human cardiac disease, results from cellular (hypertrophy) and extracellular matrix expansion (interstitial fibrosis). OBJECTIVES:This study sought to investigate whether human myocardial interstitial fibrosis in aortic stenosis (AS) is plastic and can regress. METHODS:Patients with symptomatic, severe AS (n = 181; aortic valve area index 0.4 ± 0.1 cm2/m2) were assessed pre-aortic valve replacement (AVR) by echocardiography (AS severity, diastology), cardiovascular magnetic resonance (CMR) (for volumes, function, and focal or diffuse fibrosis), biomarkers (N-terminal pro-B-type natriuretic peptide and high-sensitivity troponin T), and the 6-min walk test. CMR was used to measure the extracellular volume fraction (ECV), thereby deriving matrix volume (LV mass × ECV) and cell volume (LV mass × [1 - ECV]). Biopsy excluded occult bystander disease. Assessment was repeated at 1 year post-AVR. RESULTS:At 1 year post-AVR in 116 pacemaker-free survivors (age 70 ± 10 years; 54% male), mean valve gradient had improved (48 ± 16 mm Hg to 12 ± 6 mm Hg; p < 0.001), and indexed LV mass had regressed by 19% (88 ± 26 g/m2 to 71 ± 19 g/m2; p < 0.001). Focal fibrosis by CMR late gadolinium enhancement did not change, but ECV increased (28.2 ± 2.9% to 29.9 ± 4.0%; p < 0.001): this was the result of a 16% reduction in matrix volume (25 ± 9 ml/m2 to 21 ± 7 ml/m2; p < 0.001) but a proportionally greater 22% reduction in cell volume (64 ± 18 ml/m2 to 50 ± 13 ml/m2; p < 0.001). These changes were accompanied by improvement in diastolic function, N-terminal pro-B-type natriuretic peptide, 6-min walk test results, and New York Heart Association functional class. CONCLUSIONS:Post-AVR, focal fibrosis does not resolve, but diffuse fibrosis and myocardial cellular hypertrophy regress. Regression is accompanied by structural and functional improvements suggesting that human diffuse fibrosis is plastic, measurable by CMR and a potential therapeutic target. (Regression of Myocardial Fibrosis After Aortic Valve Replacement; NCT02174471).

Project description:BackgroundThe effect of different expressions of aortic valve disease on 3D aortic hemodynamics is unclear.PurposeTo investigate changes in aortic hemodynamics in patients with dilated ascending aorta (AAo) but different severity of aortic valve stenosis (AS) and/or regurgitation (AR).Study typeRetrospective.PopulationA total of 111 subjects (86 patients with AAo diameter ≥ 40 mm and 25 healthy controls, all with trileaflet aortic valve [TAV]). Patients were further stratified by TAV dysfunction: n = 9 with combined moderate or severe AS and AR (ASR, 56 ± 13 years), n = 14 with moderate or severe AS (AS, 64 ± 14 years), n = 33 with moderate or severe AR (AR, 62 ± 14 years), n = 30 with neither AS nor AR (no AS/AR, 63 ± 9 years).Field strength/sequence4D flow MRI on 1.5/3T systems for the in vivo analysis of aortic blood flow dynamics.AssessmentData analysis included grading of 3D AAo vortex/helix flow and AAo flow eccentricity as well as quantification of systolic peak velocities and wall shear stress (WSS).Statistical testsContinuous variables were compared by one-way analysis of variance or Kruskal-Wallis, followed by a pairwise Tukey or Dunn test if there was a significant difference.ResultsAll patients demonstrated markedly elevated vortex and helix flow compared with controls (P < 0.05). Peak velocities were significantly elevated in ASR, AS, and AR patients compared with controls (P < 0.05). Increased flow eccentricity was observed in entire AAo for AR, at the mid and distal AAo for ASR and AS, and at the proximal AAo for no AS/AR. Compared with controls, WSS in the AAo was significantly elevated in ASR and AS patients (P < 0.05) and reduced in no AS/AR patients (P < 0.05).Data conclusionThe presence of TAV dysfunction is associated with aberrant hemodynamics and altered WSS, which may play a role in the development of aortopathy.Level of evidence3 Technical Efficacy Stage: 3 J. Magn. Reson. Imaging 2020;51:481-491.

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Surrogates for myocardial power and power efficiency in patients with aortic valve disease.

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Surrogates for myocardial power and power efficiency in patients with aortic valve disease.

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