Paradoxical Low Flow Research Articles

29 - Frequency of paradoxical low flow low gradient severe aortic stenosis: critical impact of aortic flow misalignment and pressure recovery phenomenon

29 - Frequency of paradoxical low flow low gradient severe aortic stenosis: critical impact of aortic flow misalignment and pressure recovery phenomenon

Prognostic Impact of Low-Flow Severe Aortic Stenosis in Small-Body Patients Undergoing TAVR: The OCEAN-TAVI Registry

ObjectivesThis study aimed to analyze the prognostic impact of low-flow (LF) severe aortic stenosis in small-body patients undergoing transcatheter aortic valve replacement (TAVR). BackgroundWestern literature demonstrates a poor prognosis with paradoxical LF and low-flow low-gradient (LF-LG) severe aortic stenosis (AS), as defined by stroke volume index (SVi) <35 ml/m2 and mean pressure gradient <40 mm Hg with preserved left ventricular ejection fraction (LVEF). However, this poor prognosis is contested in Japan owing to the smaller body size of Japanese patients relative to that of Western patients. Additionally, there are no reports of the prognostic implication of paradoxical LF or LF-LG severe AS in small-body patients undergoing TAVR. MethodsThis was a retrospective analysis of 723 consecutive Japanese patients (median age 85 years; 32.6% male; median body surface area 1.4 m2) who underwent TAVR for severe AS at 9 sites in Japan. The primary and secondary endpoints were cumulative all-cause and cardiovascular mortality after TAVR, respectively. ResultsNinety-seven (13.4%) patients had paradoxical LF severe AS whereas 38 (5.3%) had paradoxical LF-LG with severe AS. PLF was associated with a significant increase in all-cause (hazard ratio [HR]: 3.00; 95% confidence interval [CI]: 1.34 to 6.72; p < 0.001) and cardiovascular mortality (HR: 5.58; 95% CI: 1.19 to 26.2; p < 0.01), as compared with patients’ normal flow and preserved LVEF. PLF-LG was associated with a significant increase in all-cause mortality (HR: 3.76; 95% CI: 1.09 to 13.73; p < 0.01), as compared with normal flow high gradient with preserved LVEF. SVi was an independent predictor of cardiovascular mortality on multivariate analysis after adjustments for age, sex, clinically relevant variables, and other echocardiographic parameters (HR: 1.96; 95% CI: 1.19 to 3.23; p < 0.01). ConclusionsAmong Japanese small-body patients with severe AS, both paradoxical LF and LF-LG severe AS were associated with poor outcomes following TAVR. SVi was an independent predictor of cardiovascular mortality after TAVR. (Optimised Transcatheter Valvular Intervention registry [OCEAN-TAVI]; UMIN000020423)

CRT-800.00 Safety and Efficacy of Pressure Wire Use in Hemodynamic Assessment of Paradoxical Low Flow Low Gradient Aortic Stenosis

Current guidelines discourage aortic stenosis (AS) evaluation by direct pressure measurement if echocardiography (echo) is adequate. However several studies show sizable differences between echo and catheterization (cath) lab measurements. Low flow/ low gradient (LF/LG) severe aortic stenosis (AS)

CRT-800.10 Safety and Efficacy of Pressure Wire Use in Hemodynamic Assessment of Paradoxical Low Flow Low Gradient Aortic Stenosis

Current guidelines discourage aortic stenosis (AS) evaluation by direct pressure measurement if echocardiography (echo) is adequate. However several studies show sizable differences between echo and catheterization (cath) lab measurements. Low flow/ low gradient (LF/LG) severe aortic stenosis (AS)

Echocardiographic Risk Stratification in Asymptomatic Patients with Paradoxical Low Flow Low Pressure Gradient Severe Aortic Stenosis

Echocardiographic Risk Stratification in Asymptomatic Patients with Paradoxical Low Flow Low Pressure Gradient Severe Aortic Stenosis

Role of Transesophageal Echocardiography in the Diagnosis of Paradoxical Low Flow, Low Gradient Severe Aortic Stenosis.

Background and ObjectivesPrior studies indicate that up to 35% of cases of severe aortic stenosis (AS) have paradoxical low flow, low gradient despite preserved left ventricular ejection fraction (LVEF). However, error in left ventricular outflow tract (LVOT) diameter may lead to misclassification. Herein, we determined whether measurement of LVOT diameter by transesophageal echocardiography (TEE) results in reclassification of cases to non-severe AS.Subjects and MethodsPatients with severe AS with aortic valve area (AVA) <1 cm2 by transthoracic echocardiography (TTE) within 6 months were studied. Paradoxical low flow, low gradient was defined as mean Doppler gradient (MG) <40 mm Hg and stroke volume index (SVI) ≤35 mL/m2. Preserved LVEF was defined as ≥0.50.ResultsAmong 108 patients, 12 (15%) had paradoxical low flow, low gradient severe AS despite preserved LVEF based on TTE measurement. When LVOT diameter by TEE in 2D was used, only 5 (6.3%) patients had low flow, low gradient severe AS (p<0.001). Coefficients of variability for intraobserver and interobserver measurement of LVOT were <10%. However, the limits of agreement between TTE and TEE measurement of LVOT ranged from 0.43 cm (95% confidence interval [CI]: 0.36 to 0.5) to -0.31 cm (95% CI: -0.38 to -0.23).ConclusionTEE measured LVOT diameter may result in reclassification to moderate AS in some patients due to low prevalence of true paradoxical low flow, low gradient (PLFLG) severe AS.

IMPACT OF STROKE VOLUME RECOVERY ON LONG-TERM MORTALITY AFTER SURGICAL AORTIC VALVE REPLACEMENT

In patients with aortic stenosis (AS) and preserved left ventricular ejection fraction (LVEF), those with paradoxical low flow (PLF) AS have a higher 30-day post-operative mortality following surgical aortic valve replacement (SAVR). It has been demonstrated that left ventricular stroke volume index (SVi) before SAVR (SViP) is an independent predictor of short-term mortality. However, long-term predictors of mortality in this cohort of patients remain to be determined. The objective of this study was to assess the impact of postoperative SVi at discharge (SViD) on long-term survival and echocardiographic parameters in patients with AS and preserved LVEF.

Estenosis aórtica severa de bajo flujo, bajo gradiente con función sistólica preservada, un reto diagnóstico y terapéutico: ¿qué sabemos a día de hoy?

Low-flow, low-gradient severe aortic stenosis with preserved ejection fraction of the left ventricle is a frequent entity of clinical practice. It can probably represent a more advance phase of the illness with a heavier load or time frame and a restrictive pathophysiology. There are typical clinical, hemodynamic and echocardiographic characteristics. It is an underdiagnosed condition, and as such it is undertreated, with a clearly worse prognosis with conservative treatment. In many cases, the help of «multiimaging» is required for an appropriate diagnosis and choosing the therapeutic moment. Valve replacement in patients with paradoxical low-flow, low-gradient severe aortic stenosis seem to show higher mortality in the short and long term when compared to patients with normal flow, and similar mortality if compared to low-flow aortic stenosis with depressed ejection fraction of the left ventricle. There is a lower mortality with the transcatheter aortic valve implantation in comparison with treatment of patients with symptomatic low-flow severe aortic stenosis, both for a low ejection fraction and for the paradoxical low flow, considered inoperable. No current evidence seems to exist to recommend percutaneous approach versus aortic valve replacement in high surgical risk patients with aortic stenosis with paradoxical low flow severe aortic stenosis.

Abstract 12660: Impact of Aortic Valve Replacement versus Medical Management on Survival of Low Flow Low Gradient Severe Aortic Stenosis With Normal Ejection Fraction

Background: The impact of aortic valve replacement (AVR) versus medical management (MM) in patients with paradoxical low flow is unclear. The objective of this study was to compare outcomes of AVR versus MM in patients with severe aortic stenosis and normal ejection fraction and different transaortic flow and gradient. Methods: We identified consecutive patients presenting to our echo lab with an aortic valve area (AVA) &lt; 1.0cm 2 and EF≥ 50%. We stratify patients depending on gradient (≥ 40 vs. &lt; 40 mmHg) and stroke volume index (SVI &lt; 35 vs. ≥35 ml/m 2 ). 4 groups were identified (, normal flow, high gradient [NF/HG]; normal flow, low gradient [NF/LG]; low flow, high gradient [LF/HG] and low flow, low gradient [LF/LG]. These 4 groups were also stratified depending on management (AVR vs. MM). All patients were retrospectively followed for the occurrence of death. Results: A total of 954 patients were included in analysis. Mean follow up was 2.45 ± 1.9 years. The mean age was 75.4 ± 5.6 years. Comparing all 4 AS subgroups, the mortality was higher in LF/HG followed by LF/LG, NF/HG and NF/LG (LF/HG 37.1% vs. LF/LG 33.9% vs. NF/HG 30.3%vs. NF/LG 20.2%; Log Rank Test, P=0.003). Patients who underwent medical therapy have a higher mortality than the overall cohort in all subgroups (LF/HG 44.3% vs. NF/HG 36.6% vs. LF/LG 33.7% vs. NF/LG 21.2%; Log Rank Test, P=0.001). Patients with HG had a higher chance of getting aortic valve replacement (AVR) than those with LF/LG and NF/LG (20.7% NF/HG vs. 10.6% LF/HG vs. 4.7% LF/LG and 3.6% NF/LG; P=0.01). Patients who underwent AVR had lower mortality rates when compared with the overall cohort in all subgroups (LF/HG 21.4% vs. 18.9% NF/HG vs. 6.6% LF/LG and 7.1% NF/LG; Log Rank Test, P= 0.253). Conclusion: Patients with LF/LG represent an under-recognized high-risk group with similar prognosis to NF/HG. Although these patients may benefit tremendously from AVR, they are less likely to undergo AVR when compared to HG patients.

SYSTOLIC STRAIN DYSFUNCTION PATTERNS IN LOW FLOW VERSUS HIGH FLOW SEVERE AORTIC STENOSIS WITH PRESERVED EJECTION FRACTION

We hypothesize subclinical strain dysfunction is the cause of the paradoxical Low Flow (LF) state, defined as an indexed stroke volume (SVi) ≤35ml/m2, in some patients with severe aortic stenosis and normal ejection fraction (AS). To test this hypothesis we performed an in depth strain analysis in

Impact of Classic and Paradoxical Low Flow on Survival After Aortic Valve Replacement for Severe Aortic Stenosis

BackgroundLow flow (LF) can occur with reduced (classic) or preserved (paradoxical) left ventricular ejection fraction (LVEF). ObjectivesThe objective of this study was to compare outcomes of patients with low ejection fraction (LEF), paradoxical low flow (PLF), and normal flow (NF) after aortic valve replacement (AVR). MethodsWe examined 1,154 patients with severe aortic stenosis (AS) who underwent AVR with or without coronary artery bypass grafting. ResultsAmong these patients, 206 (18%) had LEF as defined by LVEF of <50%; 319 (28%) had PLF as defined by LVEF of ≥50% but stroke volume indexed to body surface area (SVi) of ≤35 ml ∙ m−2; and 629 (54%) had NF, as defined by LVEF of ≥50% and SVi of >35 ml ∙ m2. Aortic valve area was lower in low flow/LVEF groups (LEF: 0.71 ± 0.20 cm2 and PLF: 0.65 ± 0.23 cm2 vs. NF: 0.77 ± 0.18 cm2; p < 0.001). The 30-day mortality was higher (p < 0.001) in LEF and PLF groups than in the NF group (6.3% and 6.3% vs. 1.8%, respectively). SVi and PLF group were independent predictors of operative mortality (odds ratio [OR]: 1.18, p < 0.05; and OR: 2.97, p = 0.004; respectively). At 5 years after AVR, overall survival was 72 ± 4% in LEF group, 81 ± 2% in PLF group, and 85 ± 2% in NF group (p < 0.0001). ConclusionsPatients with LEF or PLF AS have a higher operative risk, but pre-operative risk score accounted only for LEF and lower LVEF. Patients with LEF had the worst survival outcome, whereas patients with PLF and normal flow had similar survival rates after AVR. As a major predictor of perioperative mortality, SVi should be integrated in AS patients’ pre-operative evaluation.

Velocity ratio predicts outcomes in patients with low gradient severe aortic stenosis and preserved EF

ObjectiveTo evaluate the usefulness of velocity ratio (VR) in patients with low gradient severe aortic stenosis (LGSAS) and preserved EF.BackgroundLGSAS despite preserved EF represents a clinically challenging entity. Reliance on...

Prevalence and long-term outcome of aortic prosthesis-patient mismatch in patients with paradoxical low-flow severe aortic stenosis.

Patients with severe aortic stenosis (AS) and paradoxical low flow (PLF) have worse outcome compared with those with normal flow. Furthermore, prosthesis-patient mismatch (PPM) after aortic valve replacement is a predictor of reduced survival. However, the prevalence and prognostic impact of PPM in patients with PLF-AS are unknown. We aimed to analyze the prevalence and long-term survival of PPM in patients with PLF-AS. Between 2000 and 2010, 677 patients with severe AS, preserved left ventricular ejection fraction, and aortic valve replacement were included (74±8 years; 42% women; aortic valve area, 0.69±0.16 cm(2)). A PLF (indexed stroke volume ≤35 mL/m(2)) was found in 26%, and after aortic valve replacement, 54% of patients had PPM, defined as an indexed effective orifice area ≤0.85 cm(2)/m(2). The combined presence of PLF and PPM was found in 15%. Compared with patients with noPLF/noPPM, those with PLF/PPM were significantly older, with more comorbidities. They also received smaller and biological bioprosthesis more often (all P<0.01). Although early mortality was not significantly different between groups, the 10-year survival rate was significantly reduced in case of PLF/PPM compared with noPLF/noPPM (38±9% versus 70±5%; P=0.002), even after multivariable adjustment (hazard ratio, 2.58; 95% confidence interval, 1.5-4.45; P=0.0007). In this large catheterization-based study, the coexistence of PLF-AS before surgery and PPM after surgery is associated with the poorest outcome.

Assessment of low-flow, low-gradient aortic stenosis: multimodality imaging is the key to success.

In patients with aortic stenosis (AS), a low-flow state may occur with reduced LV ejection fraction (LVEF) (i.e., classic low flow) or with preserved LVEF (i.e., paradoxical low flow) and it is often associated with low gradient because the gradient is highly flow-dependent. Low-flow, low-gradient (LF-LG) AS is a frequent clinical entity generally associated with worse outcomes. A multimodality imaging approach, including comprehensive resting echocardiography, dobutamine stress echocardiography (DSE), and multidetector computed tomography (MDCT), is the key to successful management of patients with LF-LG AS, who represent a highly challenging subset from both a diagnostic and a therapeutic standpoint. DSE and quantification of aortic valve calcification by MDCT provide important information that is crucial to differentiate true-severe from pseudo-severe AS and therefore select the most appropriate therapy (i.e., AVR vs. medical). The assessment of LV flow reserve by DSE is useful to stratify the operative risk and guide decision making between surgical and transcatheter AVR. Other imaging biomarkers, such as the global LV longitudinal strain measured during DSE or the amount of myocardial fibrosis assessed by cardiac magnetic resonance imaging, may provide incremental information for risk stratification and therapeutic management in LF-LG AS, but additional studies are needed to validate and refine these emerging biomarkers further.

Immediate Improvement of Left Atrial Appendage Contractility after Transcatheter Aortic Valve Replacement in a Patient with Paradoxical Low-Flow Low-Gradient Aortic Stenosis and Preserved Left Ventricular Function

Paradoxical low-fl ow, low-gradient severe aortic stenosis with preserved left ventricular (LV) ejection fraction is a recently recognized entity characterized by impaired LV fi lling, altered myocardial function, and worse prognosis. We have shown, for the fi rst time that transcatheter aortic valve replacement is associated with immediate improvement of left atrial mechanical function, as demonstrated by the disappearance of spontaneous echo contrast and increase in left atrial appendage contractility. Key words: Left atrial function, paradoxical low-fl ow, low-gradient severe aortic stenosis, transcatheter aortic valve replacement

Aortic stenosis suspected to be severe despite low gradients.

The American College of Cardiology/American Heart Association and European Society of Cardiology/European Association for Cardio-Thoracic Surgery guidelines generally recommend aortic valve replacement (AVR) in patients with severe aortic stenosis (AS) who have symptoms, have left ventricular (LV) systolic dysfunction, or undergo coronary artery bypass graft surgery or other heart surgery.1,2 These guidelines propose a peak aortic jet velocity >4.0 m/s, a mean transvalvular gradient >40 mm Hg, and an aortic valve area (AVA) <1.0 cm2 as the criteria to be used for the identification of severe AS. However, clinicians are often confronted with patients with discordant findings, the most frequent being the combination of a small AVA (<1.0 cm2) consistent with the presence of severe AS with a low mean gradient (<40 mm Hg) rather indicating the presence of moderate AS. This situation raises uncertainty regarding the actual severity of the stenosis as well as the potential indication of AVR if the patient is symptomatic. Such discordance between AVA (small) and gradient (low) is often related to the presence of low LV outflow. Indeed, given that the pressure gradient is directly related to the squared function of transvalvular flow rate, even a modest decrease in flow rate can result in an important reduction in gradient and thus lead to an underestimation of stenosis severity. Hence, a patient with bona fide severe AS may indeed present with a low gradient if cardiac output is reduced. Moreover, this low-flow, low-gradient condition may occur in the context of either a reduced (ie, classical low flow) or preserved (ie, paradoxical low flow) LV ejection fraction (LVEF; Figure 1).3,4 However, such discordance may also be observed in patients with normal LVEF and cardiac output, in which case it may be attributable to measurement errors, a small …

Paradoxical low-flow, low-gradient aortic stenosis despite preserved left ventricular ejection fraction: new insights from weights of operatively excised aortic valves.

We reported that patients with small aortic valve area (AVA) and low flow despite preserved left ventricular ejection fraction (LVEF), i.e. 'paradoxical' low flow (PLF), have worse outcomes compared with patients with normal flow (NF), although they generally have a lower mean gradient (MG). The aortic valve weight (AVW) excised at the time of valve replacement is a flow-independent marker of stenosis severity. The objective of this study was to compare the AVW of patients with PLF and MG<40 mmHg with the AVW of patients with NF and MG≥40 mmHg. We recruited 250 consecutive patients undergoing valve replacement (Cohort A) for severe stenosis. Among them, 33 (13%) were in PLF [LVEF > 50% but stroke volume index (SVi) ≤ 35 mL/m(2)] with MG < 40 mmHg (PLF-LG group) and 105 (42%) were in NF (LVEF > 50% and SVi > 35 mL/m(2)) with MG ≥ 40 mmHg (NF-HG group). Despite a much lower MG (29 ± 7 vs. 53 ± 10 mmHg; P < 0.0001), patients in the PLF-LG group had a similar AVA (0.73 ± 0.12 vs. 0.69 ± 0.13; P = 0.19) compared with those in the NF-HG group. The AVW [median (interquartile): 1.90 (1.63-2.50) vs. 2.60 (1.66-3.32)] and prevalence of bicuspid phenotype (15 vs. 42%) were lower in the PLF-LG group than in the NF-HG group. However, AVWs analysed separately in the tricuspid and bicuspid valves were similar in both groups [tricuspid valves: 1.80 (1.63-2.50) vs. 2.30 (1.58-3.00) g; P = 0.26 and bicuspid valves: 2.72 (1.73-3.61) vs. 2.60 (2.10-3.55) g; P = 0.93]. When using cut-point values of AVW established in another series of non-consecutive patients (n = 150, Cohort B) with NF and concordant Doppler-echocardiographic findings, we found that the percentage of patients with evidence of severe stenosis in Cohort A was 70% in patients with PLF-LG and 86% in patients with NF-HG. The aortic valve weight data reported in this study provide evidence that a large proportion of patients with PLF and low-gradient have a severe stenosis and that the gradient may substantially underestimate stenosis severity in these patients. A multi-parametric approach including all Doppler-echocardiographic parameters of valve function as well as other complementary diagnostic tests may help correctly identify these patients.

ROLE OF TRANSESOPHAGEAL ECHOCARDIOGRAPHY IN THE DIAGNOSIS OF PARADOXICAL LOW FLOW, LOW GRADIENT SEVERE AORTIC STENOSIS DESPITE PRESERVED EJECTION FRACTION

Prior studies reported up to 35% of cases of severe aortic stenosis (AS) have paradoxical low flow despite preserved left ventricular ejection fraction (EF). It is unclear if some of these cases were misclassified due to error in left ventricular outflow tract (LVOT) diameter. We hypothesized that

Estenosis aórtica severa con fracción de expulsión normal de flujo bajo paradójico y bajo gradiente

Introductionsevere aortic stenosis impacts the morbidity and mortality of patients. It is defined as a valve area < 1cm2 or < than 0.6cm2/m2 of BSA, transvalvular gradients > 40mm Hg and peak velocities > 4m/s. When patients have severe aortic stenosis and preserved left ventricle ejection fraction, these values are expected to be high, but a subset of patients where these values are lower has been found and this fact has led to reassess the cutoff points to define the disease. ObjectiveTo assess the prevalence of paradoxical low-flow/low-gradient severe aortic stenosis with preserved ejection fraction and determine the hemodynamic characteristics and clinical impact in patients. MethodsA retrospective study conducted during 1999–2010 in an echocardiography service, which evaluated 839 patients with severe aortic stenosis and preserved left ventricle ejection fraction. The sample was divided into two groups: normal flow group, defined as an indexed stroke volume > 35mL /m2 and paradoxical low-flow group, with indexed stroke volume ≤ 35mL/m2 and their hemodynamic characteristics, valvular and ventricular geometry as well as survival were evaluated. Results49.1% were classified as paradoxical low-flow and 50.9 % as normal flow. The average age was 66.4 years and 56.1% were women. The average mean arterial pressure was 92.5mm Hg, mean gradient 41.2mm Hg and mean ejection fraction 60%. When comparing the two groups, patients with paradoxical low flow had higher valvular-arterial impedance (6.2 versus 4.25mm Hg/mL/m, p<0.001), greater LV diastolic diameter (4.76 versus 4.62cm, p<0.001) and higher systemic vascular resistance (2.18 versus 1.51mm Hg * min/L, p<0.001). There was no differen ce in survival. ConclusionParadoxical low-flow/low-gradient aortic stenosis is a common entity that is associated with increased left ventricular afterload. To improve the treatment of these patients it is necessary to reassess the diagnostic criteria and obtain a more thorough evaluation of myocardial function in addition to the left ventricle ejection fraction. Although there was no difference in survival between the two groups, previous studies warn that these patients require closer monitoring and better understanding of their physiology.

Paradoxical Low Flow Aortic Valve Stenosis: Incidence, Evaluation, and Clinical Significance

Paradoxical low-flow (PLF) aortic stenosis is defined by a stroke volume index <35 ml/m(2) despite the presence of preserved LV ejection fraction (≥ 50 %). This entity is typically characterized by pronounced LV concentric remodeling with small LV cavity, impaired LV filling, increased arterial load, and reduced LV longitudinal shortening. Patients with PLF also have a worse prognosis compared to patients with normal flow. Because of the low flow state, these patients often have a low gradient despite the presence of severe stenosis, thus leading to discordant AS grading (i.e., aortic valve area < 1.0 cm(2) but mean gradient < 40 mmHg) and thus uncertainty about the indication of aortic valve replacement. Stress echocardiography and aortic valve calcium score by computed tomography may be helpful to differentiate true from pseudo severe stenosis and thereby guide therapeutic management in these patients. Aortic valve replacement improves outcomes in patients with PLF low gradient AS having evidence of severe stenosis. Transcatheter aortic valve replacement may provide an interesting alternative to surgery in these patients.