The Peak to Mean Pressure Decrease Ratio: A New Method of Assessing Aortic Stenosis

2005 ◽  
Vol 18 (6) ◽  
pp. 674-678 ◽  
Author(s):  
John Chambers ◽  
Ronak Rajani ◽  
Matthew Hankins ◽  
Robert Cook
Keyword(s):  
Aortic Stenosis ◽  
New Method ◽  
Pressure Decrease ◽  
Mean Pressure

scholarly journals Use and success evaluation of percutaneous aortic balloon valvuloplasty in different hemodynamic entities of severe aortic stenosis in the TAVR era

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
K Piayda ◽  
A Wimmer ◽  
H Sievert ◽  
K Hellhammer ◽  
S Afzal ◽  
...  
Keyword(s):  
Heart Failure ◽  
Aortic Valve ◽  
Aortic Stenosis ◽  
Aortic Valve Replacement ◽  
Pressure Gradient ◽  
Severe Aortic Stenosis ◽  
Primary Treatment ◽  
Low Flow ◽  
Mean Pressure ◽  
The Mean

Abstract Background In the era of transcatheter aortic valve replacement (TAVR), there is renewed interest in percutaneous balloon aortic valvuloplasty (BAV), which may qualify as the primary treatment option of choice in special clinical situations. Success of BAV is commonly defined as a significant mean pressure gradient reduction after the procedure. Purpose To evaluate the correlation of the mean pressure gradient reduction and increase in the aortic valve area (AVA) in different flow and gradient patterns of severe aortic stenosis (AS). Methods Consecutive patients from 01/2010 to 03/2018 undergoing BAV were divided into normal-flow high-gradient (NFHG), low-flow low-gradient (LFLG) and paradoxical low-flow low-gradient (pLFLG) AS. Baseline characteristics, hemodynamic and clinical information were collected and compared. Additionally, the clinical pathway of patients (BAV as a stand-alone procedure or BAV as a bridge to aortic valve replacement) was followed-up. Results One-hundred-fifty-six patients were grouped into NFHG (n=68, 43.5%), LFLG (n=68, 43.5%) and pLFLG (n=20, 12.8%) AS. Underlying reasons for BAV and not TAVR/SAVR as the primary treatment option are displayed in Figure 1. Spearman correlation revealed that the mean pressure gradient reduction had a moderate correlation with the increase in the AVA in patients with NFHG AS (r: 0.529, p<0.001) but showed no association in patients with LFLG (r: 0.145, p=0.239) and pLFLG (r: 0.030, p=0.889) AS. Underlying reasons for patients to undergo BAV and not TAVR/SAVR varied between groups, however cardiogenic shock or refractory heart failure (overall 46.8%) were the most common ones. After the procedure, independent of the hemodynamic AS entity, patients showed a functional improvement, represented by substantially lower NYHA class levels (p<0.001), lower NT-pro BNP levels (p=0.003) and a numerical but non-significant improvement in other echocardiographic parameters like the left ventricular ejection fraction (p=0.163) and tricuspid annular plane systolic excursion (TAPSE, p=0.066). An unplanned cardiac re-admission due to heart failure was necessary in 23.7% patients. Less than half of the patients (44.2%) received BAV as a bridge to TAVR/SAVR (median time to bridge 64 days). Survival was significantly increased in patients having BAV as a staged procedure (log-rank p<0.001). Conclusion In daily clinical practice, the mean pressure gradient reduction might be an adequate surrogate of BAV success in patients with NFHG AS but is not suitable for patients with other hemodynamic entities of AS. In those patients, TTE should be directly performed in the catheter laboratory to correctly assess the increase of the AVA. BAV as a staged procedure in selected clinical scenarios increases survival and is a considerable option in all flow states of severe AS. (NCT04053192) Figure 1 Funding Acknowledgement Type of funding source: None

scholarly journals In-Shoe Plantar Pressure Measurement—Influence of Insole Placement on Selected Parameters during Running

Proceedings ◽  
2020 ◽  
Vol 49 (1) ◽  
pp. 50 ◽  
Author(s):  
Franziska Mally ◽  
Otto Hofstätter ◽  
Markus Eckelt
Keyword(s):  
Pressure Measurement ◽  
Plantar Pressure ◽  
Center Of Pressure ◽  
Pressure Sensing ◽  
Pressure Decrease ◽  
Running Shoes ◽  
Mean Pressure ◽  
Plantar Pressure Measurement ◽  
Healthy Participants ◽  
Anterior Posterior

While it is assumed that pressure-sensing insoles are usually placed directly below the foot and on top of the shoes’ standard insoles, nearly no previously published study actually describes the procedure, which leaves a slight uncertainty. Therefore, the aim of this study was to evaluate whether the placement has an influence on selected parameters or not. Five healthy participants took part in the measurements and ran on a treadmill at a running velocity of 10 km/h with three different running shoes. Plantar pressure was measured using pressure-sensing insoles, which were once placed on top and once below the shoes’ standard insoles. Selected parameters were the maximum and mean pressure and the range of the center of pressure (COP) in anterior–posterior and medial–lateral directions. The results indicate that maximum and mean pressure decrease when the pressure-sensing insole lies below the shoe’s insole and the medial–lateral COP is the least effected parameter.

scholarly journals Echocardiographic Evaluation of Aortic Stenosis – Normal Flow and Low Flow Scenarios

2014 ◽  
Vol 9 (2) ◽  
pp. 92
Author(s):  
Ian G Burwash ◽  
Keyword(s):  
Clinical Outcome ◽  
Aortic Stenosis ◽  
Patient Management ◽  
Low Flow ◽  
Normal Flow ◽  
Prognostic Information ◽  
Echocardiographic Evaluation ◽  
Mean Pressure ◽  
Echocardiographic Assessment ◽  
Valve Area

The echocardiographic evaluation of the patient with aortic stenosis (AS) has evolved in recent years, beyond confirming the diagnosis and measuring the resting mean pressure gradient or valve area. New echocardiographic approaches have developed to address the clinical dilemmas related to discordant haemodynamic data, asymptomatic haemodynamically severe AS and low-flow, low-gradient AS in order to better evaluate the disease severity, enhance the risk stratification of patients and provide important prognostic information. This article reviews the echocardiographic evaluation of the AS patient and focuses on the echocardiographic assessment of the haemodynamic severity, the prediction of clinical outcome and the use of echocardiography to guide patient management in the presence of normal flow and low flow scenarios.

Physical Properties and Hydrostatic Function of the Swimbladder of Herring (Clupea harengus L.)

1962 ◽  
Vol 19 (4) ◽  
pp. 635-656 ◽  
Author(s):  
Vivien M. Brawn
Keyword(s):  
Surface Pressure ◽  
Sea Water ◽  
Gas Production ◽  
Clupea Harengus ◽  
Gas Release ◽  
Pressure Reduction ◽  
Neutral Buoyancy ◽  
Reduced Pressure ◽  
Pressure Decrease ◽  
Mean Pressure

Living herring at the depth of adjustment had a mean sinking factor of 1003, density of 1.026 g/ml, relative sensitivity of 0.8 and percentage swimbladder volume of 4.2. Neutral buoyancy was attained at a mean pressure reduction of 5.5% from the adjusted pressure. Swimbladder gas was under an average excess pressure of 1 cm Hg. Gas was released through the posterior swimbladder duct during pressure reduction in 105 out of 109 herring observed. Gas release occurred at a mean pressure decrease of 6% in rapidly swimming herring, at 32% in moderately swimming fish and brought the herring to within 19% of perfect adjustment to a new reduced pressure within half an hour. Herring could compensate for their increased buoyancy during pressure decrease until this was reduced by gas release. Decompression at rates up to 123 cm Hg/sec was not fatal after 16 hours at the greater pressure. No recovery of buoyancy after gas loss occurred in herring held 24 hours in running sea water even if fine air bubbles were present. Recovery occurred if these fish had access to the surface. Gas production by bacterial activity as a means of restoring buoyancy was not established. Herring responded to rapid pressure increases by swimming upwards. They could compensate for their increased density following pressure increase of 300% and survive increases of 430%. Herring from 10 to 25 feet depth at sea were positively buoyant at surface pressure when anaesthetized. Thus in nature herring are adjusted to pressures greater than surface pressure. It is suggested that they take in air when feeding at the surface at night and slowly pass this to the swimbladder on returning to greater depths by day.

scholarly journals Effect of the 2017 European Guidelines on Reclassification of Severe Aortic Stenosis and Its Influence on Management Decisions for Initially Asymptomatic Aortic Stenosis

2020 ◽  
Vol 13 (12) ◽  
Author(s):  
Daniel C.S. Chan ◽  
Anvesha Singh ◽  
John P. Greenwood ◽  
Dana K. Dawson ◽  
Chim C. Lang ◽  
...  
Keyword(s):  
Aortic Stenosis ◽  
Severe Aortic Stenosis ◽  
Calcium Score ◽  
Cardiovascular Death ◽  
End Point ◽  
Exercise Tolerance Testing ◽  
Asymptomatic Patients ◽  
Mean Pressure ◽  
European Society Of Cardiology ◽  
Tolerance Testing

Background: The 2017 European Society of Cardiology guidelines for valvular heart disease included changes in the definition of severe aortic stenosis (AS). We wanted to evaluate its influence on management decisions in asymptomatic patients with moderate-severe AS. Methods: We reclassified the AS severity of the participants of the PRIMID-AS study (Prognostic Importance of Microvascular Dysfunction in Asymptomatic Patients With AS), using the 2017 guidelines, determined their risk of reaching a clinical end point (valve replacement for symptoms, hospitalization, or cardiovascular death) and evaluated the prognostic value of aortic valve calcium score and biomarkers. Patients underwent echocardiography, cardiac magnetic resonance imaging, exercise tolerance testing, and biomarker assessment. Results: Of the 174 participants, 45% (56/124) classified as severe AS were reclassified as moderate AS. This reclassified group was similar to the original moderate group in clinical characteristics, gradients, calcium scores, and remodeling parameters. There were 47 primary end points (41 valve replacement, 1 death, and 5 hospitalizations—1 chest pain, 2 dyspnea, 1 heart failure, and 1 syncope) over 368±156 days follow-up. The severe and reclassified groups had a higher risk compared with moderate group (adjusted hazard ratio 4.95 [2.02–12.13] and 2.78 [1.07–7.22], respectively), with the reclassified group demonstrating an intermediate risk. A mean pressure gradient ≥31 mm Hg had a 7× higher risk of the primary end point in the reclassified group. Aortic valve calcium score was more prognostic in females and low valve area but not after adjusting for gradients. NT-proBNP (N-terminal pro-brain-type natriuretic peptide) and myocardial perfusion reserve were associated with the primary end point but not after adjusting for positive exercise tolerance testing. Troponin was associated with cardiovascular death or unplanned hospitalizations. Conclusions: Reclassification of asymptomatic severe AS into moderate AS was common using the European Society of Cardiology 2017 guidelines. This group had an intermediate risk of reaching the primary end point. Exercise testing, multimodality imaging, and lower mean pressure gradient threshold of 31 mm Hg may improve risk stratification. Registration: URL: https://www.clinicaltrials.gov . Unique identifier: NCT01658345.

A rapid noninvasive blood pressure measurement method for discrete value and full waveform determination

1996 ◽  
Vol 80 (1) ◽  
pp. 307-314 ◽  
Author(s):  
R. P. Schnall ◽  
N. Gavriely ◽  
S. Lewkowicz ◽  
Y. Palti
Keyword(s):  
Blood Pressure ◽  
Measurement Method ◽  
Circulatory Arrest ◽  
Blood Pressure Measurement ◽  
New Method ◽  
Noninvasive Blood Pressure ◽  
Noninvasive Methods ◽  
Arterial Blood ◽  
Mean Pressure ◽  
Highly Correlated

A new noninvasive measurement method providing rapid measurement of systemic arterial blood pressure (BP) and its validation is described. The method combines precisely timed electrocardiographic-gated rapid release of occluding counter-pressure (600 mmHg/s) with photoplethysmographic detection of radial artery filling to measure arterial opening pressure. A complete BP waveform is reconstructed from multiple repetitions of the measurement cycle at successively increasing time intervals relative to the electrocardiographic signal. Systolic and diastolic values can be measured within two to four cardiac cycles at the peak and trough of the BP wave. The new method was compared with sphygmomanometry in 26 randomly selected subjects over a sphygmomanometric pressure range of 53-110 (diastolic) and 100-190 mmHg (systolic). The mean pressure differences between the sphygmomanometric and new methods were -1.3 +/- 15.2 (SD) (systolic) and 0.7 +/- 9.9 mmHg (diastolic), and corresponding BP values measured by these methods were highly correlated [P < 0.001; R2 = 0.87 (systolic); R2 = 0.80 (diastolic)]. The new method was compared with sphygmomanometry and intra-arterial BP in six patients. These tests confirmed the method's validity compared with established methods. The new method was ostensibly immune to mechanical perturbations when tested during cycle ergometry at 60 W. The new method may facilitate the study of circulatory phenomena previously inaccessible by available noninvasive methods and minimizes patient discomfort and circulatory arrest at the measurement site.

scholarly journals Reducing the Inconsistency between Doppler and Invasive Measurements of the Severity of Aortic Stenosis Using Aortic Valve Coefficient: A Retrospective Study on Humans

2014 ◽  
Vol 2014 ◽  
pp. 1-6
Author(s):  
Anup K. Paul ◽  
Rupak K. Banerjee ◽  
Arumugam Narayanan ◽  
Mohamed A. Effat ◽  
Jason J. Paquin
Keyword(s):  
Aortic Valve ◽  
Aortic Stenosis ◽  
Dynamic Pressure ◽  
Clinical Parameter ◽  
Aortic Valve Area ◽  
Diagnostic Parameter ◽  
Diagnostic Parameters ◽  
Mean Pressure ◽  
Marginal Improvement ◽  
Valve Area

Background. It is not uncommon to observe inconsistencies in the diagnostic parameters derived from Doppler and catheterization measurements for assessing the severity of aortic stenosis (AS) which can result in suboptimal clinical decisions. In this pilot study, we investigate the possibility of improving the concordance between Doppler and catheter assessment of AS severity using the functional diagnostic parameter called aortic valve coefficient (AVC), defined as the ratio of the transvalvular pressure drop to the proximal dynamic pressure. Method and Results. AVC was calculated using diagnostic parameters obtained from retrospective chart reviews. AVC values were calculated independently from cardiac catheterization (AVCcatheter) and Doppler measurements (AVCdoppler). An improved significant correlation was observed between Doppler and catheter derived AVC (r=0.92, P<0.05) when compared to the correlation between Doppler and catheter measurements of mean pressure gradient (r=0.72, P<0.05) and aortic valve area (r=0.64, P<0.05). The correlation between Doppler and catheter derived AVC exhibited a marginal improvement over the correlation between Doppler and catheter derived aortic valve resistance (r=0.89, P<0.05). Conclusion. AVC is a refined clinical parameter that can improve the concordance between the noninvasive and invasive measures of the severity of aortic stenosis.

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