Systemic Arterial Compliance Research Articles

Aortic valve replacement reduces valvuloarterial impedance but does not affect systemic arterial compliance in elderly men with degenerative calcific trileaflet aortic valve stenosis.

Standard methods of quantifying aortic valve stenosis (AS), which focus entirely on the valve itself, do not adequately characterize the magnitude, predict the onset, progression, and severity of symptoms, or identify the incidence of subsequent adverse events. Valvuloarterial impedance (Z(va)) is an index of global left ventricular (LV) afterload that incorporates valvular and arterial loads. The authors tested the hypothesis that aortic valve replacement (AVR) reduces Z(va) but does not affect the arterial component of LV afterload in elderly patients with degenerative calcific trileaflet AS. Observational study. Veterans affairs medical center. Eight elderly (age, 79 ± 4 years) men with moderate-to-severe AS and normal preoperative LV function (ejection fraction, 61% ± 9%) scheduled for AVR with or without coronary artery bypass graft surgery were studied after institutional review board approval. None. A comprehensive TEE examination was performed during isoflurane-fentanyl-rocuronium anesthesia. Doppler echocardiography was used to measure pressure gradients across the aortic valve, stroke volume (continuity equation), and aortic valve area using standard techniques. Z(va) was determined as (systolic arterial pressure+mean gradient)/stroke volume index. Energy loss index was calculated as (aortic area × aortic valve area)/([aortic area--aortic valve area]× body surface area). The stroke work loss was obtained as (mean gradient × 100/[systolic arterial pressure+mean gradient]). The ratio of stroke volume index to pulse pressure was used to measure systemic arterial compliance. Z(va), energy loss index, stroke work loss, and systemic arterial compliance were assessed before and 15 minutes after cardiopulmonary bypass. Systemic and pulmonary hemodynamics (invasive catheters) were similar after versus before AVR. Aortic valve area increased significantly (p<0.05) with AVR (0.92 ± 0.26 cm(2) to 1.94 ± 0.35 cm(2)), concomitant with decreases in peak and mean gradients (60 ± 17 mmHg to 15 ± 8 mmHg and 38 ± 11 mmHg to 8 ± 5 mmHg, respectively) and peak blood flow velocity (3.9 ± 0.5 m · s(-1) to 1.9 ± 0.5 m · s(-1)). AVR reduced Z(va) (4.6 ± 1.0 mmHg · mL(-1) · m(-2) to 3.5 ± 0.3 mmHg · mL(-1) · m(-2)) and improved energy loss index (0.55 ± 0.16 cm(2) · m(-2) to 1.58 ± 0.48 cm(2) · m(-2)) concomitant with a decline in stroke work loss (25% ± 6% to 7% ± 4%), but systemic arterial compliance remained unchanged (0.63 ± 0.13 compared with 0.70 ± 0.12 mL · mmHg(-1)· m(-2)). The current results showed that AVR acutely reduced Zva, improved energy loss index, and decreased stroke work loss, but did not affect systemic arterial compliance in elderly men with degenerative calcific trileaflet AS.

Resting ventricular-vascular function and exercise capacity in heart failure with preserved ejection fraction: a RELAX trial ancillary study.

Exercise intolerance is a hallmark of heart failure, but factors associated with impaired exercise capacity in heart failure with preserved ejection fraction are unclear. We hypothesized that in heart failure with preserved ejection fraction, the severity of resting ventricular and vascular dysfunction are associated with impairment in exercise tolerance as assessed by peak oxygen consumption. Subjects with heart failure with preserved ejection fraction enrolled in the PhosphodiesteRasE-5 Inhibition to Improve CLinical Status And EXercise Capacity in Diastolic Heart Failure (RELAX) clinical trial (n=216) underwent baseline Doppler echocardiography, cardiopulmonary exercise testing, and cardiac MRI. RELAX participants were elderly (median age 69 years) and 48% were women. Ejection fraction (60%) and stroke volume (77 mL) were normal, while diastolic dysfunction (medial E/e', 16; deceleration time, 185 ms; left atrial volume, 44 mL/m(2)) and increased arterial load (arterial elastance, 1.51 mm Hg/mL) were evident. Peak oxygen consumption was reduced (11.7 mLkg(-1)min(-1), 1141 mL/min) and age, sex, body mass index, hemoglobin, and chronotropic response collectively explained 64% of the variance in raw peak oxygen consumption (mL/min). After adjustment for these variables, left ventricular structure (diastolic dimension [1.5%, P=0.008] and left ventricular mass [1.6%, P=0.008]), resting stroke volume (2.0%, P=0.002), left ventricular diastolic dysfunction (deceleration time [0.9%, P=0.03] and E/e' [1.4%, P=0.009]), and arterial function (arterial elastance [2.1%, P=0.002] and systemic arterial compliance [1.5%, P=0.007]), each explained only a small additional portion of the variance in peak oxygen consumption. In heart failure with preserved ejection fraction, potentially modifiable factors (obesity, anemia, and chronotropic incompetence) are strongly associated with exercise capacity, whereas resting measures of ventricular and vascular structure and function are not. http://www.clinicaltrials.gov. Unique identifier: NCT00763867.

Associations Between Echocardiographic Arterial Compliance and Incident Cardiovascular Disease in Blacks: The ARIC Study

Systemic arterial compliance is sometimes derived by echocardiographic stroke volume to pulse pressure ratios. Few studies have assessed echocardiographic arterial compliance in blacks or its associations with explicit, rather than composite, cardiovascular disease (CVD) outcomes. We analyzed a subset (n = 1,887) of blacks (mean age = 59 ± 6 years; 65% women) in the Atherosclerosis Risk in Communities study who were free of prevalent CVD and were imaged by echocardiography in 1993-1995. Arterial compliance was calculated by the aortic velocity time integral and brachial pulse pressure ratio (VTI/PP). Associations between VTI/PP and subsequent CVD (defined as first incident stroke, coronary event, or heart failure) were modeled by Cox regression after controlling for demographics, anthropometry, and cardiac risk factors. For comparison, CVD hazard ratios were also calculated for pulse pressure quartiles. Over a mean follow-up of 13 ± 4 years, 237 subjects (12%) developed coronary disease, 322 (16%) developed heart failure, and 180 (9%) experienced a stroke. Hazard ratios contrasting lowest with highest quartiles of VTI/PP were 2.3 (95% confidence interval (CI) = 1.7-3.1) for composite CVD, 2.1 (95% CI = 1.3-3.2) for coronary disease, 2.5 (95% CI = 1.7-3.6) for heart failure, and 2.7 (95% CI = 1.6-4.5) for stroke. Hazard ratios contrasting widest with narrowest pulse pressure quartiles were 1.7 (95% CI = 1.3-2.2) for composite CVD, 1.6 (95% CI = 1.0-2.4) for coronary heart disease, 1.8 (95% CI = 1.2-2.6) for heart failure, and 2.3 (95% CI = 1.3-3.9) for stroke. In blacks, the VTI/PP ratio has stronger associations with both composite and individual CVD outcomes than does pulse pressure.

Increased benefit of interleukin-1 inhibition on vascular function, myocardial deformation, and twisting in patients with coronary artery disease and coexisting rheumatoid arthritis.

We investigated the effects of anakinra, an interleukin-1 receptor antagonist, on coronary and left ventricular function in coronary artery disease (CAD) patients with rheumatoid arthritis. In a double-blind crossover trial, 80 patients with rheumatoid arthritis (60 with CAD and 20 without) were randomized to a single injection of anakinra or placebo and after 48 hours to the alternative treatment. At baseline and 3 hours after treatment, we assessed (1) flow-mediated dilation of brachial artery; (2) coronary flow reserve, ejection fraction, systemic arterial compliance, and resistance by echocardiography; (3) left ventricular global longitudinal and circumferential strain, peak twisting, untwisting velocity by speckle tracking; and (4) interleukin-1β, nitrotyrosine, malondialdehyde, protein carbonyl, and Fas/Fas ligand levels. At baseline, patients with CAD had 3-fold higher interleukin-1β, protein carbonyl, higher nitrotyrosine, malondialdehyde, and Fas/Fas ligand than non-CAD (P<0.05). After anakinra, there was a greater improvement of flow-mediated dilation (57±4% versus 47±5%), coronary flow reserve (37±4% versus 29±2%), arterial compliance (20±18% versus 2±17%), resistance (-11±19% versus 9±21%), longitudinal strain (33±5% versus 18±2%), circumferential strain (22±5% versus 13±5%), peak twisting (30±5% versus 12±5%), untwisting velocity (23±5% versus 13±5%), ejection fraction (12±5% versus 0.5±5%), apoptotic and oxidative markers, and, in particular, of protein carbonyl (35±20% versus 14±9%) in CAD than in non-CAD patients (P<0.01). No changes in the examined markers were observed after placebo. Interleukin-1 inhibition causes a greater improvement in endothelial, coronary aortic function in addition to left ventricular myocardial deformation and twisting in rheumatoid arthritis patients with CAD than in those without. http://www.clinicaltrials.gov. Unique identifier: NCT01566201.

Local Stiffness of the Carotid and Femoral Artery Is Associated With Incident Cardiovascular Events and All-Cause Mortality: The Hoorn Study

This study sought to investigate the association of local and segmental arterial stiffness with incident cardiovascular events and all-cause mortality. The association of different stiffness indices, in particular of carotid, brachial, and femoral stiffness, with cardiovascular disease and mortality is currently unknown. In a population-based cohort (n = 579, mean age 67 years, 50% women, 23% with type 2 diabetes [by design]), we assessed local stiffness of carotid, femoral, and brachial arteries (by ultrasonography), carotid-femoral pulse wave velocity (cfPWV), aortic augmentation index, and systemic arterial compliance. After a median follow-up of 7.6 years, 130 participants had a cardiovascular event and 96 had died. The hazard ratios (HRs) (95% confidence intervals [CIs]) per 1 SD for cardiovascular events and all-cause mortality, respectively, were HR: 1.22 (95% CI: 0.95 to 1.56) and 1.51 (95% CI: 1.11 to 2.06) for lower carotid distensibility; HR: 1.19 (95% CI: 1.00 to 1.41) and 1.28 (95% CI: 1.07 to 1.53) for higher carotid elastic modulus; HR: 1.08 (95% CI: 0.88 to 1.31) and 1.43 (95% CI: 1.10 to 1.86) for lower carotid compliance; HR: 1.39 (95% CI: 1.06 to 1.83) and 1.27 (95% CI: 0.90 to 1.79) for lower femoral distensibility; HR: 1.25 (95% CI: 0.96 to 1.63) and 1.47 (95% CI: 1.01 to 2.13) for lower femoral compliance; and HR: 1.56 (95% CI: 1.23 to 1.98) and 1.13 (95% CI: 0.83 to 1.54) for higher cfPWV. These results were adjusted for age, sex, mean arterial pressure, and cardiovascular risk factors. Mutual adjustments for each of the other stiffness indices did not materially change these results. Brachial stiffness, augmentation index, and systemic arterial compliance were not associated with cardiovascular events or mortality. Carotid and femoral stiffness indices are independently associated with incident cardiovascular events and all-cause mortality. The strength of these associations with events may differ per stiffness parameter.

Carotid Artery and Aortic Stiffness Evaluation in Aortic Stenosis

In aortic stenosis (AS), the combination of risk factors can progressively lead to an increased arterial rigidity, which can be evaluated by the carotid artery and aortic stiffness (β index). The aim of this study was to investigate the relationship between carotid and aortic β index, left ventricular (LV) function, plasma brain natriuretic peptide (BNP) level, and symptoms in patients with AS. Comprehensive echocardiography including Doppler tissue imaging of the mitral annulus was performed in 53 patients with AS (aortic valve area < 1.2 cm(2)) and preserved LV ejection fractions (≥ 50%). Carotid β index was automatically derived from ultrasound wall tracking of the right carotid artery. The mitral E/e' ratio was used to estimate LV filling pressures. Carotid β index was higher in women than in men and was significantly correlated with age (P < .0001), diastolic arterial pressure (P = .046), pulse pressure (P = .006), and systemic arterial compliance (P = .001). Interestingly, carotid β index was significantly correlated with E/e' ratio (P < .0001) and plasma BNP level (P = .011). In multivariate regression analysis, carotid β index was an independent predictor of E/e' ratio (P < .0001) and of BNP level (P = .02). Moreover, carotid β index was significantly higher in symptomatic patients (P = .009). Aortic β index was significantly correlated with carotid β index (P < .0001), E/e' ratio (P = .004), and BNP (P < .001) and was significantly higher in symptomatic patients (P = .037). In patients with moderate to severe AS and preserved LV ejection fractions, the presence of increased carotid artery and aortic stiffness, assessed using carotid and aortic β index, is independently associated with elevated LV filling pressures, BNP level, and symptoms.

Short-term hemodynamic effect of angiotensin-converting enzyme inhibition in patients with severe aortic stenosis: A placebo-controlled, randomized study

In patients with severe aortic stenosis (AS), treatment with angiotensin-converting enzyme inhibitors has previously been considered contraindicated. However, there is a lack of clinical evidence to confirm these potential hemodynamic risks and benefits. Forty-four patients with severe AS (aortic valve area <1 cm(2)) were randomized to treatment with trandolapril 22 mg daily/placebo (1:1). Right heart catheterization and echocardiography were performed at rest and during exercise at baseline and on day 3. Follow-up was performed before valve replacement or after a maximum of 8 weeks, when exercise echocardiography was repeated. Compared with placebo, systolic blood pressure and systemic arterial compliance significantly changed at day 3 (-14 ± 11 vs -5 ± 13 mm Hg, P = .02, and 0.08 ± 0.16 vs -0.05 ± 0.86 mL/m(2) per mm Hg, P = .03, respectively). Changes in left ventricular end systolic volume (LVESV) was nonsignificant (-8 ± 9 vs -3 ± 11 mL, P = .17). At a median of 49 days of follow-up, changes in LVESV and N-terminal pro-brain natriuretic peptide were even lower revealing significant differences between the groups (-7.8 ± 2.6 vs -0.5 ± 2.5 mL, P = .04, and -19 ± 7 vs 0.8 ± 6 pmol/L, P = .04, respectively). No episodes of symptomatic hypotension were noted, and other hemodynamic parameters remained unchanged. Angiotensin-converting enzyme inhibition in severe AS caused a decrease in LVESV and N-terminal pro-brain natriuretic peptide with other hemodynamic parameters preserved both at rest and during exercise implying hemodynamic improvement with left ventricular unloading.

The Complex Nature of Discordant Severe Calcified Aortic Valve Disease Grading: New Insights From Combined Doppler Echocardiographic and Computed Tomographic Study

With concomitant Doppler echocardiography and multidetector computed tomography (MDCT) measuring aortic valve calcification (AVC) load, this study aimed at defining: 1) independent physiologic/structural determinants of aortic valve area (AVA)/mean gradient (MG) relationship; 2) AVC thresholds best associated with severe aortic stenosis (AS); and 3) whether, in AS with discordant MG, severe calcified aortic valve disease is generally detected. Aortic stenosis with discordant markers of severity, AVA in severe range but low MG, is a conundrum, unresolved by outcome studies. Patients (n= 646) with normal left ventricular ejection fraction AS underwent Doppler echocardiography and AVC measurement by MDCT. On the basis of AVA-indexed-to-body surface area (AVAi) and MG, patients were categorized as concordant severity grading (CG) with moderate AS (AVAi >0.6 cm²/m², MG<40 mm Hg), severe AS (AVAi≤0.6 cm²/m², MG≥ 40 mm Hg), discordant-severity-grading (DG) with low-MG (AVAi≤0.6 cm(2)/m(2), MG<40 mm Hg), or high-MG (AVAi >0.6 cm(2)/m(2), MG≥40 mm Hg). The MG (discordant in 29%) was strongly determined by AVA and flow but also independently and strongly influenced by AVC-load (p< 0.0001) and systemic arterial compliance (p< 0.0001). The AVC-load (median [interquartile range]) was similar within patients with DG (low-MG: 1,619 [965 to 2,528] arbitrary units [AU]; high-MG: 1,736 [1,209 to 2,894] AU; p= 0.49), higher than CG-moderate-AS (861 [427 to 1,519] AU; p< 0.0001) but lower than CG-severe-AS (2,931 [1,924 to 4,292] AU; p< 0.0001). The AVC-load thresholds separating severe/moderate AS were defined in CG-AS with normal flow (stroke-volume-index >35 ml/m(2)). The AVC-load, absolute or indexed, identified severe AS accurately (area under the curve≥0.89, sensitivity≥86%, specificity≥79%) in men and women. Upon application of these criteria to DG-low MG, at least one-half of the patients were identified as severe calcified aortic valve disease, irrespective of flow. Among patients with AS, MG is often discordant from AVA and is determined by multiple factors, valvular (AVC) and non-valvular (arterial compliance) independently of flow. The AVC-load by MDCT, strongly associated with AS severity, allows diagnosis of severe calcified aortic valve disease. At least one-half of the patients with discordant low gradient present with heavy AVC-load reflective of severe calcified aortic valve disease, emphasizing the clinical yield of AVC quantification by MDCT to diagnose and manage these complex patients.

Outcome and Impact of Surgery in Paradoxical Low-Flow, Low-Gradient Severe Aortic Stenosis and Preserved Left Ventricular Ejection Fraction

The clinical relevance and management of paradoxical low-flow, low-gradient aortic stenosis (LFLG-AS) with preserved left ventricular ejection fraction remain debated. The aim of this study is to determine the features and outcome of LFLG-AS assessed using cardiac catheterization. Between 2000 and 2010, 768 patients with preserved left ventricular ejection fraction (>50%) and severe AS (valve area ≤ 1 cm(2)) without other valvular disease underwent cardiac catheterization. Mean age was 74 ± 8 years, 42% were women, and 46% had associated coronary artery disease. The prevalence of LFLG (indexed left ventricular stroke volume <35 mL/m(2) and mean gradient <40 mm Hg), normal flow high gradient, normal flow low gradient, and low flow high gradient were 13%, 50%, 22%, and 15%, respectively. Compared with patients with normal flow high gradient, those with LFLG were significantly older, with significantly reduced systemic arterial compliance and vascular resistances and increased valvulo-arterial impedance (all P<0.05). Ten-year survival was reduced in LFLG-AS (32 ± 9%) compared with normal flow high gradient (66 ± 4%; P=0.0002). After adjustment for other risk factors, LFLG-AS was independently associated with reduced long-term survival (hazard ratio, 1.85; 95% confidence interval, 1.08-3.07; P=0.02). However, despite higher operative mortality, patients with LFLG-AS undergoing aortic valve replacement seemed to have better long-term survival than those managed conservatively (5-year survival rate: 63 ± 6% versus 38 ± 15%; P=0.007; hazard ratio, 0.23; 95% confidence interval, 0.09-0.59; P=0.002). This large cardiac catheterization-based study reports that the LFLG-AS entity is not rare and is associated with worse outcome whether treated medically or surgically. However, these patients may have better long-term survival if treated surgically. Further prospective studies are needed to confirm this finding.

Reduced systemic arterial compliance and subclinical LV systolic dysfunction in COPD

Background: We hypothesized that COPD leads to alterations in systemic vascular structure and that systemic arterial compliance (SAC) would have impact on the LV function even in a population free of clinical cardiovascular disease. Methods: Patients with COPD (GOLD stage I-IV) and matched healthy controls were included. Those with LV disease were excluded. Coronary heart disease was excluded by exercise ECG. The following TDI based indices for LV function were performed: LV acceleration during isovolumic contraction (LVIVA), myocardial performance-index (LVMPI) and peak systolic velocity (LVSm). SAC was calculated as stroke volume (ml)/systemic pulse pressure (mmHg). Inflammatory markers (Table) were measured. Results: Consistent with reduced SAC, a significant increase in systolic blood pressure was observed in the patient group (Table). Stroke volume did not differ between the groups. Significantly higher levels of the biomarkers were found (all p<0.01) (Table). There were significant associations at p<0.01 between SAC and CRP and IL-6 in patients with COPD, but not in controls. Pulse pressure correlated with metalloproteinase (MMP-9), r=0.44 (p<0.01). LVEF was preserved; TDI measures for LV function were all significantly impaired in COPD (Table). SAC correlated significantly with LVIVA, LV Sm and LVMPI, r=-0.3, 0.4 and -0.3 (p<0.01), respectively. View this table: Table 1 Conclusions: COPD patients showed subclinical LV dysfunction by TDI along with systemic inflammation, increased elastolytic activity and reduced arterial compliance, compared to controls. The reduction in SAC provides one mechanism for the observed LV dysfunction in these patients.

Resting level of plasma brain natriuretic peptide and response to exercise as predictors of outcomes in asymptomatic patients with aortic stenosis

Purpose: Exercise stress echocardiography is useful in the management and risk stratification of patients with asymptomatic aortic stenosis (AS). Resting brain natriuretic peptides (BNP) level is associated with increased risk of adverse events in AS patients. The incremental prognostic value of BNP response during exercise is unknown. The objectives of this study were to assess the correlates of the plasma level of BNP during exercise as well as its usefulness to predict outcomes in asymptomatic patients with AS. Methods: Resting and exercise Doppler-echocardiographic data and BNP levels were prospectively collected in 211 asymptomatic AS patients in 2 centers. Results: Plasma BNP level increased significantly from rest to exercise (65±86 to 91±111 pg/mL, p<0.0001). The factors independently related to peak-exercise BNP were systemic arterial compliance (SAC: β=-0.76±0.32, p=0.02), resting mean gradient (MG: β=0.01±0.005, p=0.04), and change in stroke volume index (SVi) during exercise (β=0.01±0.005, p=0.02). During a mean follow-up of 1.8±1.3 years, 7 patients died and 97 underwent AVR motivated by development of symptoms or LV dysfunction. Higher peak-exercise BNP level was associated with higher occurrence of adverse events (2-yrs event-free survival according to tertiles of peak-exercise BNP: T1: 84±5% vs. T2: 60±7% vs. T3: 29±6%, p<0.0001). Stenosis was slightly more severe in T2 and T3 compared to T1 (MG: 43±15 and 43±16 vs. 37±13 mmHg, respectively; p=0.03). In multivariable analysis, after adjustment for age, gender, hypertension, MG, and valvulo-arterial impedance, T2 (HR=2.3; 95% CI: 1.3-4.3; p=0.005) and T3 (HR=5.3; 95% CI: 3.0-9.6; p<0.0001) tertiles of peak-exercise BNP were powerful independent predictors of events. Further adjustment for resting BNP, exercise-induced increase in MG and SVi led to similar results (T2: HR=2.2; 95% CI: 1.2-4.2; p=0.007; and T3: HR=4.8; 95% CI: 2.5-9.3; p<0.0001). The association between highest tertiles of peak-exercise BNP and outcomes remained highly significant (p<0.0001) in both subsets of patients with low or high resting BNP (i.e. ≤ or >43 pg/mL; median value). Conclusion: This study reports that, in asymptomatic patients with AS, peak-exercise BNP level provides important incremental prognostic value beyond what is achieved by demographic and echocardiographic data, as well as resting BNP level. These findings lend support to the measurement of BNP during exercise to enhance risk stratification in asymptomatic AS.

Valvuloarterial impedance – parameter of overall load in aortic stenosis and hypertension

Background: It has been reported that 30-40% of patients with aortic stenosis (AS) are hypertensive. The presence of hypertension can affect decision making in patients with AS, hence it could be valuable to consider alternative ultrasonographic measurments. Valvulo-arterial impedance (z va ) is a parameter of overall load, obtained by summation of valvular and vascular load. Valvular component of pressure overload is caused by an obstruction on the stenosed aortic valve level. Vascular component of the load occurs because of the systemic vascular resistence increase caused by hypertension. Z va is superior to the standard indexes of aortic stenosis severity in predicting left ventricle (LV) dysfunction. Aim: We tried to determine the influence of valvular and peripheral stress on the LV wall in patients with coexisting aortic stenosis and hypertension. Patients and Methods: This study included 18 consecutive patients (11 male and 7 female). These patients were divided into four strata: patients with aortic stenosis and hypertension (AS+H), patients with aortic stenosis (AS), patients with hypertension (H) and control group (N). Results: After computing z va, the highest average value was found in the AS+H stratum (z va=7,46 mmHg/ml/m 2 ). Average z va values in AS stratum (z va =5,78 mmHg/ml/m 2 ) and H stratum (z va=4,75 mmHg/ml/m 2 ) were reduced in comparison to AS+H stratum. In the N stratum we found the lowest average z va value, zva=3,85 mmHg/ml/m 2 . In addition to z va , we also calculated systemic arterial compliance (SAC) in all strata. SAC is a measure of peripheral arterial load as a result of arterial system thickening, caused by arterial hypertension. After calculating average SAC values for all strata, we established the following results: the lowest average SAC values were in the AS+H stratum, SAC=0,43 ml/m 2 /mmHg, in the AS stratum the average SAC value was lower, SAC=0,62 ml/m2 /mmHg, and in the H and N stratum, the average SAC value was equal (SAC=0,73 ml/m 2 / mmHg). Conclusion: Hypertension creates an excessive LV hemodynamic load on valvular load caused by aortic stenosis. We also determined that systemic arterial compliance in double load decreases in regards to individual compliances measured in patients with aortic stenosis and hypertension.

Impact of Valvuloarterial Impedance on 2-Year Outcome of Patients Undergoing Transcatheter Aortic Valve Implantation

Elderly patients with severe aortic stenosis undergoing transcatheter aortic valve implantation (TAVI) often have increased calcification and fibrosis of the aorta. Indices that account for the severity of valvular obstruction and systemic vascular impedance may better assess total left ventricular afterload. The aims of the present study were to evaluate changes in valvuloarterial impedance (Zva), systemic arterial compliance, and systemic vascular resistance after TAVI and to investigate the prognostic value of these parameters. A total of 116 patients (49% men; mean age, 81 ± 8 years) with symptomatic severe aortic stenosis underwent TAVI. Zva, systemic arterial compliance, and systemic vascular resistance were measured at baseline and 1 and 12 months after TAVI. The primary end point was all-cause mortality. After TAVI, there was a significant reduction in Zva (from 5.40 ± 1.52 mm Hg/mL/m(2) at baseline to 4.13 ± 1.17 mm Hg/mL/m(2) at 1 month and 4.35 ± 1.38 mm Hg/mL/m(2) at 1 year, P < .001). Systemic arterial compliance (from 0.57 ± 0.27 to 0.57 ± 0.28 and 0.53 ± 0.27 mL/m(2)/mm Hg, P = .408) and systemic vascular resistance (from 1,938 ± 669 to 1,856 ± 888 and 1,871 ± 767, dyne·s·cm(-5), P = .697) did not change significantly over time. During a median follow-up period of 25 months, survival rates of patients with baseline Zva ≥ 5 mm Hg/mL/m(2) were lower compared with those with Zva < 5 mm Hg/mL/m(2) (82% vs 91%, respectively, log-rank P = .04). On multivariate Cox proportional-hazards analysis, baseline Zva was independently associated with all-cause mortality (hazard ratio, 1.48; 95% confidence interval, 1.05-2.07; P = .025). In patients undergoing TAVI, there is a significant postprocedural reduction in Zva, but there is no reduction in systemic arterial compliance or vascular resistance. Baseline Zva is an independent predictor of overall mortality at 2-year follow-up.

Continuous-flow pump model study: the effect on pump performance of pump characteristics and cardiovascular conditions

This model study evaluates the effect of pump characteristics and cardiovascular data on hemodynamics in atrio-aortic VAD assistance. The model includes a computational circulatory sub-model and an electrical sub-model representing two rotary blood pumps through their pressure-flow characteristics. The first is close to a pressure generator-PG (average flow sensitivity to pressure variations, -0.047lmmHg(-1)); the second is closer to a flow generator-FG (average flow sensitivity to pressure variations, -0.0097lmmHg(-1)). Interaction with VAD was achieved by means of two interfaces, behaving as impedance transformers. The model was verified by use of literature data and VAD onset conditions were used as a control for the experiments. Tests compared the two pumps, at constant pump speed, in different ventricular and circulatory conditions: maximum ventricular elastance (0.44-0.9mmHgcm(-3)), systemic peripheral resistance (781-1200gcm(-4)s(-1)), ventricular diastolic compliance C p (5-10-50cm(3)mmHg(-1)), systemic arterial compliance (0.9-1.8cm(3)mmHg(-1)). Analyzed variables were: arterial and venous pressures, flows, ventricular volume, external work, and surplus hemodynamic energy (SHE). The PG pump generated the highest SHE under almost all conditions, in particular for higher C p (+50%). PG pump flow is also the most sensitive to E max and C p changes (-26 and -33%, respectively). The FG pump generally guarantees higher external work reduction (54%) and flow less dependent on circulatory and ventricular conditions. The results are evidence of the importance of pump speed regulation with changing ventricular conditions. The computational sub-model will be part of a hydro-numerical model, including autonomic controls, designed to test different VADs.

Circumferential ascending aortic strain and aortic stenosis

Two-dimensional speckle tracking (2D-ST) echocardiography for the measurement of circumferential ascending thoracic aortic strain (CAAS) in the context of aortic stenosis (AS) is not elucidated. Purpose This study assesses the thoracic ascending aortic deformation using 2D-ST echocardiography in AS patients. Population and methods Forty-five consecutive patients with an aortic valvular area (AVA) ≤0.85 cm(2)/m(2) were included. Regarding aortic deformation, the global peak CAAS was the parameter used, and an average of six segments of arterial wall deformation was calculated. The corrected CAAS was calculated as the global CAAS/pulse pressure (PP). Aortic stiffness (β2) index was assessed according to ln(Ps/Pd)/CAAS. The sample was stratified according to the stroke volume index (SVI) as: Group A (low flow, SVI ≤35 mL/m(2); n = 19) and Group B (normal flow, SVI >35 mL/m(2); n = 26). The mean age was 76.8 ± 10.3 years, 53.3% were male, the mean indexed AVA was 0.43 ± 0.15 cm(2)/m(2), and the mean CAAS was 6.3 ± 3.0%. The CAAS was predicted by SVI (β = 0.31, P < 0.01) and by valvulo-arterial impedance (Zva). The corrected CAAS was correlated with the M-mode guided aortic stiffness index (β1) (r = -0.39, P < 0.01), and was predicted by SVI, Zva, and systemic arterial compliance (β = 0.15, P < 0.01). The β2 index was significantly higher for the low-flow patients (16.1 ± 4.8 vs. 9.8 ± 5.3, P < 0.01), and was predicted by SVI (β -0.58, P < 0.01) and PP (β = 0.17, P < 0.01). Global CAAS was more accurate to predict low flow than Zva, systolic function and systemic vascular resistance. In patients with moderate-to-severe aortic stenosis, SVI and LV afterload-related variables were the most important determinants of 2S-ST global CAAS.

Reduced systemic arterial compliance measured by routine Doppler echocardiography: A new and independent predictor of mortality in patients with type 2 diabetes mellitus

ObjectivesThis study was designed to examine the prognostic value of systemic arterial compliance (SAC) by Doppler-echocardiography in patients with type 2 diabetes mellitus (T2D). BackgroundReduced SAC has been shown to predict outcomes in patients with hypertension. T2D is associated with accelerated arterial stiffening and increased cardiovascular events. We hypothesized that SAC measured by Doppler-echocardiography would independently predict mortality in patients with T2D. MethodsSince 2001, SAC calculated as the ratio of stroke volume index to arterial pulse pressure by sphygmomanometer is routinely performed in our laboratory. Data from 505 consecutive patients with T2D were retrospectively analyzed. Based on a previously validated cut-off value of SAC < 0.6 ml/m2/mmHg, patients were divided into Group 1, reduced SAC, 255 patients (50%) and Group 2, preserved SAC, 250 patients (50%). The primary endpoint was overall mortality. ResultsPatients with reduced SAC had significantly lower 5-year survival than those with preserved SAC (66 ± 5 vs. 82 ± 5%, p = 0.02) and a 1.57-fold (95% CI: 1.04–2.43; p = 0.03) increased risk of mortality after adjusting for other risk factors. Blood pressure did not predict mortality and pseudo-normalized blood pressures related to LV dysfunction and low cardiac output were found in 75 patients (15%). ConclusionReduced SAC is encountered frequently in T2D, is an independent predictor of mortality and allows identification of patients who, despite a normal blood pressure, are at increased risk. Future studies are necessary to further evaluate the clinical utility of this simple echocardiographic parameter and therapies are needed to alter vascular stiffness to improve clinical outcomes in these high-risk patients.

The Syndrome of Degenerative Calcific Aortic Stenosis: Prevalence of Multiple Pathophysiologic Disorders in Association with Valvular Stenosis and Their Implications

We hypothesized that degenerative calcific aortic stenosis (DCAS) is a syndrome influenced by factors beyond aortic valve stenosis (AS). The aim of this study was to assess how frequently DCAS is complicated by increased vascular load, systolic and/or diastolic left ventricular (LV) dysfunction, and comorbid disorders. In 215 consecutive patients > 60 years of age with severe and moderate AS, we analyzed systemic arterial compliance, global hemodynamic load, LV ejection fraction (EF), the presence of diastolic dysfunction, and other valvular or systemic disorders. A total of 164 patients had severe AS and 51 had moderate AS. In patients with severe AS, the prevalence of increased vascular load was 42%; LV systolic and diastolic dysfunction was present in 27% and 42%; other valve diseases in 23%; and comorbid disorders in 82%. In the moderate AS group, abnormal vascular load was found in 52%; LV systolic and diastolic dysfunction was prevalent in 26% and 31%; other valve diseases in 17%; and comorbid disorders in 78% patients. More than half the patients in both groups had symptoms. In both severe and moderate AS groups, the prevalence of increased vascular load and systolic dysfunction was higher in the symptomatic group. Considerable number of patients with DCAS have abnormal vascular load, abnormal LV function, and significant coexisting disorders. These could influence the total pathophysiologic burden on the heart and symptom expression. Thus, DCAS should not be considered just as valvular stenosis, but a syndrome of DCAS because of the diagnostic, prognostic, and therapeutic implications of various factors associated with it.

Effect of antihypertensive therapy on ventricular-arterial mechanics, coupling, and efficiency

To investigate the effect of antihypertensive therapy on ventricular-arterial mechanics, coupling, and efficiency in early-stage hypertension. We studied 527 participants from two clinical trials assessing the effect of blood pressure lowering on diastolic function. Participants were aged ≥45 years with early-stage hypertension, no heart failure, ejection fraction (EF) ≥50%, and diastolic dysfunction using Doppler echocardiography. Effective arterial afterload and its components were assessed along with measures of left ventricular (LV) structure and function prior to and after 24-38 weeks of antihypertensive therapy. Systolic blood pressure decreased from 154 ± 18 to 137 ± 15 mmHg at follow-up. Blood pressure reduction was associated with decreases in ventricular and arterial stiffness, improvements in systemic arterial compliance and resistance, enhanced LV ejection, and reduction in cardiac work (all P < 0.001). Changes in Ea/Ees ratio were inversely correlated with those in EF (r = -0.25; P < 0.001), stroke work index (r = -0.13; P = 0.007), and LV efficiency (r = -0.98; P < 0.001); and directly related to changes in mitral E/e' (r = 0.12; P = 0.01). Adjusting for age and blood pressure change, women and obese individuals had less enhancement in ventricular-arterial coupling and efficiency compared with men and non-obese individuals (P = 0.04 and 0.007, respectively). Antihypertensive therapy reduces arterial and ventricular stiffness, enhances ventricular-arterial coupling, reduces cardiac work, and improves LV efficiency, systolic, and diastolic function. Attenuated responses in women and among obese subjects suggest that structure-function changes may be less reversible in these groups, possibly explaining their greater susceptibility to ultimately develop heart failure.

Polikistik Over Sendromunda, Brakiyal Arter’in Endotel Bağımlı ve Bağımsız Vazodilatasyonun Araştırılması

Objective: The endothelium plays an important role in the regulation of vascular tone. Arterial distensibility is a marker of functional and structural wall properties. A decreased distensibility is an important risk factor for cardiovascular disease. Hyperandrogenism may be related to impaired systemic arterial vascular compliance. In this study, using a non-invasive ultrasonography method, we investigated endothelium dependent and endothelium independent vasodilation in the brachial artery of the patients with polycystic ovary syndrome (PCOS). Materials and Methods: Fourteen hyperandrogenemic patients with PCOS and 18 healthy age and BMI matched controls were included in the study. Serum DHEAS, androstenedione, total and free testosterone levels were measured for the diagnosis of hyperandrogenism. Brachial artery diameter was measured at baseline, during post-occlusion reactive hyperaemia (flow-mediated, endothelium dependent dilation), and after 400 mg glyceryl trinitrate sublingually (endothelium-independent dilation). Vasodilation was expressed as the percentage change relative to the baseline diameter. Results: Baseline flow and blood pressure were similar in the patients with PCOS and healthy subjects. Baseline vessel diameter (mm) was not statistically different between the patients with PCOS (3.2p0.3) and control group (3.1p0.4). Endothelium dependent dilation in PCOS patients (7.8p5.4%) was significantly (pl0.05) lower than in control subjects (14.9p7.9%). Endothelium-independent dilation in PCOS patients (10.8p4.2%) was also significantly (pl0.01) lower than in controls subjects (20.3p9.9%). Conclusion: The results of this study suggest that the patients with PCOS have impaired endothelium-dependent and independent vasodilation and it could be determined non-invasive methods. Key words: Polycystic Ovary Syndrome; Hyperandrogenism; Brachial Artery; Vasodilation.

Asymptomatic Aortic Stenosis: The Influence of the Systemic Vasculature on Exercise Time

Changes in the peripheral vasculature occur in patients with aortic stenosis (AS). The aims of the present study were to characterize peripheral arterial waveforms and aortic pulsewave velocity (PWV) in patients with AS and to determine their relationship to exercise time. The study included 101 patients with a median age of 68 years (range, 27-84 years) with at least moderate AS. Patients underwent transthoracic echocardiography, an assessment of the radial artery waveform and PWV using a SphygmoCor device, and a treadmill exercise stress test. The mean brachial systolic blood pressure was 143 ± 23 mm Hg in patients with severe AS and 135 ± 15 mm Hg in patients with moderate AS (P = .04). The mean radial augmentation index was 102 ± 20% in patients with severe AS and 89 ± 16% in those with moderate AS (P < .001). The radial augmentation index was related to the effective valve orifice area (R = -0.45, P = .001), the peak transvalvular pressure difference (R = 0.33, P = .001), and the mean transvalvular pressure difference (R = 0.33, P = .001). On univariate analysis, exercise time was related to systemic arterial compliance (R = 0.312, P = .008) and PWV (R = -0.44, P < 0.001). On multivariate analysis, after adjusting for age, AS severity, and PWV, only age was a significant predictor of exercise time (β = -0.46; P = .006; 95% confidence interval, -15 to -3). In patients with asymptomatic moderate to severe AS, exercise capacity is influenced only by age, not by resting measures of aortic valve stenosis or aortic stiffness.