Aortic stiffness: an old concept for new insights into the pathophysiology of functional mitral regurgitation

Aortic stiffness plays a role in the discrepancy between mitral valve lesion severity and hemodynamic burden of secondary mitral regurgitation

BACKGROUND

By the framework of proportionate/disproportionate secondary mitral regurgitation (sMR), disproportionate sMR is characterized by a low left ventricular stroke volume (SV) and an out of proportion regurgitant fraction (RF) for the same effective regurgitant orifice area (EROA). The degree of aortic stiffness is a determinant of the ventricular forward SV. We aim to analyze the importance of aortic stiffness in influencing the discrepancy between measures of mitral valve lesion severity (EROA) and sMR hemodynamic burden (regurgitant volume [RV] and RF).

METHODS

We enrolled stable patients with heart failure with reduced ejection fraction (HFrEF) and at least mild sMR. Mitral EROA, RV, RF and aortic pulse wave velocity (PWV) were measured by echocardiography. We defined three groups based on the degree of actual RF deviation from RF estimated by the linear regression equation of RF on EROA (concordant, low-discordant [residuals lower-than -5%] and high-discordant RF [residuals higher-than 5%]).

RESULTS

117 patients were analyzed (68±13 years; female 30%; LVEF 33±8%; EROA 16±12mm2; RV 24±15 ml; RF 27±13%; PWV 6.6 ± 3.2 m/s). LVEF, end-diastolic-volume and EROA didn't differ among groups. PWV and RV were higher in patients with high-discordant RF (p ≤ 0.01), whereas total left ventricular-SV and left ventricular outflow tract-SV (LVOT-SV) were lower (p ≤ 0.0004). PWV was associated with LVOT-SV (r=-0.3;p = 0.0008) and RV (r = 0.3;p = 0.0009). High-discordant RF was predicted by PWV (p = 0.001) independently of LVOT-SV and RV.

CONCLUSION

In this HFrEF cohort with sMR, higher PWV was associated with higher-than-expected RF for a given EROA. Aortic stiffness might play a role in the discrepancy between mitral valve lesion severity and sMR hemodynamic burden.

Right Ventricular Function Improves Early After Percutaneous Mitral Valve Repair in Patients Suffering From Severe Mitral Regurgitation

Background

Percutaneous mitral valve edge-to-edge procedure (PMVR) using the MitraClip^® system (Abbot Vascular, CA) is an established therapy for severe mitral regurgitation (MR) in patients judged inoperable or at high surgical risk. Besides determining exercise capacity, right ventricular (RV) function has prognostic value in heart failure and after cardiac surgery. We therefore investigated the impact of PMVR on RV function in patients with severe MR.

Methods and Results

Sixty-three patients undergoing PMVR at our department were prospectively enrolled. Transthoracic echocardiography was performed before, early (2–12d) after PMVR and after 3 months, including advanced echocardiographic analyses such as 3D imaging and strain analyses. At baseline, all patients presented with advanced heart failure symptoms. Etiology of MR was more often secondary and, if present, left ventricular (LV) dysfunction was predominantly caused by ischemic cardiomyopathy. PMVR substantially reduced MR to a grade ≤ 2 in most patients. Echocardiographic assessment revealed a largely unchanged LV systolic function early after PMVR, while in contrast RV function substantially improved after PMVR [3D RV EF (%): pre 33.7% [27.4; 39.6], post 40.0% [34.5; 46.0] (p < 0.01 vs. pre), 3 months 42.8% [38.3; 48.1] (p < 0.01 vs. pre); 2D RV GLS (%): pre −12.9% [−14.5; −10.5], post −16.0% [−17.9; −12.6] (p < 0.01 vs. pre), 3 months −17.2% [−21.7; −14.9] (p < 0.01 vs. pre)]. Factors that attenuated RV improvement were larger ventricular volumes, lower LV function, secondary MR, and a higher STS score (all p < 0.05).

Conclusion

By using advanced echocardiographic parameters, we discovered an early improvement of RV function after PMVR that is preserved for months, independent from changes in LV function. Improvement of RV function was less pronounced in patients presenting with an advanced stage of heart failure and a higher burden of comorbidities reflected by the STS score.

The role of ventricular-arterial coupling in cardiac disease and heart failure: assessment, clinical implications and therapeutic interventions. A consensus document of the European Society of Cardiology Working Group on Aorta & Peripheral Vascular Diseases, European Association of Cardiovascular Imaging, and Heart Failure Association

Ventricular-arterial coupling (VAC) plays a major role in the physiology of cardiac and aortic mechanics, as well as in the pathophysiology of cardiac disease. VAC assessment possesses independent diagnostic and prognostic value and may be used to refine riskstratification and monitor therapeutic interventions. Traditionally, VAC is assessed by the non-invasive measurement of the ratio of arterial (Ea) to ventricular end-systolic elastance (Ees). With disease progression, both Ea and Ees may become abnormal and the Ea/Ees ratio may approximate its normal values. Therefore, the measurement of each component of this ratio or of novel more sensitive markers of myocardial (e.g. global longitudinal strain) and arterial function (e.g. pulse wave velocity) may better characterize VAC. In valvular heart disease, systemic arterial compliance and valvulo-arterial impedance have an established diagnostic and prognostic value and may monitor the effects of valve replacement on vascular and cardiac function. Treatment guided to improve VAC through improvement of both or each one of its components may delay incidence of heart failure and possibly improve prognosis in heart failure. In this consensus document, we describe the pathophysiology, the methods of assessment as well as the clinical implications of VAC in cardiac diseases and heart failure. Finally, we focus on interventions that may improve VAC and thus modify prognosis.

Arterial stiffness and mitral regurgitation in arterial hypertension: an intriguing pathophysiological link

BACKGROUND

We examined the relative impact of arterial stiffness on the presence and/or severity of chronic mitral regurgitation (MR) in hypertensive patients.

METHODS

We prospectively enrolled 141 untreated hypertensive patients (mean age 56.6 ± 11.5 years): 94 with MR, 47 without MR. As a measure of arterial stiffness, pulse wave velocity (PWV) was assessed by applanation tonometry. Assessment of MR severity was obtained through calculation of effective regurgitant orifice area (EROA) and vena contracta by standard two-dimensional transthoracic echocardiography.

RESULTS

PWV appears to progressively increase according to the presence and severity of MR (no MR = 7.3 ± 1.1 m/s, mild MR = 7.9 ± 1.3 m/s, moderate MR = 9.0 ± 1.7 m/s, severe MR = 13.3 ± 4.1 m/s; P < 0.001 for all comparisons). EROA was positively correlated with age (P = 0.011), left atrial volume index (P = 0.023), PWV (P < 0.001) and augmentation index (P < 0.001), and negatively correlated with left ventricular ejection fraction (P = 0.002) and heart rate (HR) (P = 0.018). On stepwise multivariate logistic regression analysis, only PWV (OR = 2.87, 95% CI 1.750-4.738, P < 0.001) and HR (OR = 0.94, 95% CI 0.895-0.994, P = 0.02) appeared to be independent predictors of severe MR. Receiver operating characteristic curves showed that a cutoff of 9 m/s for PWV provided the best sensitivity/specificity for predicting both the presence of any degree of MR (sensitivity 73%, specificity 87%, AUC = 0.863; P < 0.001) and MR severity (sensitivity 100%, specificity 81%, AUC = 0.954; P < 0.001).

CONCLUSION

Reduced arterial elasticity because of increased stiffness may be an important marker for the presence and severity of MR in hypertensive patients.

Echocardiographically Derived Pulse Wave Velocity and Diastolic Dysfunction Are Associated with an Increased Incidence of Atrial Fibrillation in Patients with Systolic Heart Failure

BACKGROUND

Chronic heart failure (CHF) is an established risk factor of atrial fibrillation (AF), but the prognostic value of cardiac and hemodynamic parameters in assessing the risk of developing AF among patients with CHF is less defined.

METHODS AND RESULTS

We followed an outpatients cohort of CHF patients secondary to left ventricular (LV) systolic dysfunction, who were free of AF at baseline. All patients underwent clinical evaluation, comprehensive echocardiography, and blood drawing in the same morning. Aortic pulse wave velocity (aPWV), a measure of aortic stiffness, was determined by Doppler echocardiography. A total of 77 patients (age 63 ± 9 years; 79% male) with mean LVEF (34 ± 8%) formed the study population. Fifteen patients developed incidental AF. At baseline, CHF patients who developed AF during follow-up had higher E-wave velocity (75 ± 2 cm/sec vs. 60 ± 2 cm/sec; P = 0.02), higher difference duration between mitral and pulmonary vein A velocity (A'-A), (10 ± 35 msec vs. 43 ± 44 msec P = 0.02), aPWV (7.1 ± 2.6 vs. 5.3 ± 1.9 m/sec P = 0.004), and furosemide dosage (110 ± 145 mg vs. 49 ± 48 mg P = 0.01) than those remaining free from AF. The two groups of patients did not significantly differ in terms of NYHA, LV volumes, ejection fraction, left atrial volume, creatinine, hemoglobin, renin, epinephrine, amino-terminal propeptide of type III and I procollagens, ACE inhibitor, and β-blocker dose (P > 0.1 for all). Notably, higher aPWV (P = 0.01) and longer A-A' duration (P = 0.04) were associated with an increased incidence of AF, independently of potential confounders.

CONCLUSIONS

Increased aortic stiffness and LV diastolic dysfunction are strong predictors of new onset of AF among patients with systolic CHF.

Comparison of pulse wave velocity assessed by three different techniques: Arteriograph, Complior, and Echo-tracking

Arterial stiffness estimated by pulse wave velocity (PWV) is an independent predictor of cardiovascular morbidity and mortality. Although recommended by the current guidelines, clinical applicability of this parameter is difficult, due to differences between the various techniques used to measure it and to biological variability. Our aim was to compare PWV assessed by 3 different commercially available systems. 100 subjects (51 ± 16 years, 45 men) were evaluated using the 3 methods: an oscillometric technique (Arteriograph, PWV-A); a piezo-electric method (Complior, PWV-C); and an high-resolution ultrasound technique implemented with an Echo-tracking system (Aloka, PWV-E). Conventional biological markers were measured. Correlations of PWV measured by the 3 methods were poor (r = 0.39, r = 0.39, and r = 0.31 for PWV-A vs. PWV-C, PWV-A vs. PWV-E, and PWV-C vs. PWV-E, respectively, all p < 0.05). By Bland-Altman analysis, mean difference (±SD) of PWV-A vs. PWV-C was -1.9 ± 2.0 m/s, of PWV-A vs. PWV-E -3.6 ± 1.9 m/s, and of PWV-C vs. PWV-E -2.7 ± 1.9 m/s, with a wide coefficient of variation (22.3, 25.7, and 25.7 %, respectively). As expected, PWV-A, PWV-C, and PWV-E correlated with other arterial stiffness parameters, such as intima-media thickness (r = 0.22, r = 0.22, and r = 0.36, respectively), E p (r = 0.37, r = 0.26, and r = 0.94, respectively), and augmentation index measured by Arteriograph method (r = 0.66, r = 0.35, and r = 0.26, respectively); all p < 0.05. Assessment of PWV is markedly dependent on the technique used to measure it, related to various methods for measuring traveled distance of the arterial wave. Our results suggest the urgent need to establish reference values of PWV for each of these techniques, separately, to be used in routine clinical practice.

Assessment of arterial stiffness and cardiovascular hemodynamics by oscillometric method in psoriasis patients with normal cardiac functions

Arterial stiffness is associated with increased cardiovascular risk. Pulse wave velocity (PWV) and augmentation index (AIx) are non-invasive markers for assessment of arterial stiffness. Increased arterial stiffness is associated with atherosclerosis in patients with psoriasis. Previous studies have shown that high neutrophil-to-lymphocyte ratio (NLR) predicts poor cardiovascular outcome. The aim of this study was to evaluate arterial stiffness and cardiovascular hemodynamics by oscillometric method in psoriasis patients with normal cardiac functions. Fifty consecutive patients with the diagnosis of psoriasis and 50 controls were included in the study. NLR was calculated as the ratio of neutrophil count to lymphocyte count. All patients underwent echocardiographic examination. Measurements of arterial stiffness were carried out using a Mobil-O-Graph arteriograph system. Fifty patients with psoriasis (26 male, mean age 43.3 ± 13.2 years) and 50 controls (33 male, mean age 45.0 ± 6.1 years) were included into the study. The distribution of cardiovascular risk factors was similar between the two groups, and NLR was significantly higher in patients with psoriasis (2.74 ± 1.78 versus 1.82 ± 0.52, p = 0.002). There was a weak correlation between NLR and PASI score without reaching statistical significance (r = 0.300, p = 0.060). While echocardiographic and hemodynamic parameters were comparable between psoriasis and control groups, heart rate was significantly higher in psoriasis group (81.5 ± 15.1 and 75.2 ± 11.8 beats/min, p = 0.021). Psoriasis patients had significantly higher AIx and PWV values as compared to controls (25.8 ± 13.1 versus 17.4 ± 12.3%, p = 0.001 and 6.78 ± 1.42 versus 6.18 ± 0.80 m/s, p = 0.011, respectively). AI and PWV were significantly associated with psoriasis when adjusted by heart rate (p = 0.005, odds ratio 1.04, 95% confidence interval 1.01-1.08 and p = 0.035, odds ratio 1.52, 95 % confidence interval 1.02-2.26, respectively). PWV significantly correlated with blood pressure, lipid levels, and several echocardiographic indices. AIx only correlated with left atrial diameter (r = 291, p = 0.040). Linear regression analysis was performed to find predictors of PWV. Central systolic blood pressure, left atrial diameter, and total cholesterol were independent predictors of PWV. PWV and AIx were significantly higher in patients with psoriasis. Assessment of arterial stiffness parameters may be useful for early detection of cardiovascular deterioration in psoriasis patients with normal cardiac functions. Novel inflammatory biomarkers such as NLR may elucidate the mechanism of vascular dysfunction in such patients.

Prognostic impact of regional arterial stiffness in hypertensive patients

Many reports have shown that brachial-ankle pulse wave velocity (baPWV) and carotid-femoral PWV are prognostic factors for cardiovascular diseases. We evaluated heart-carotid PWV, heart-femoral PWV (hfPWV), and femoral-ankle PWV (faPWV) using carotid and femoral sensors. Our objectives were to reveal correlations among PWVs and to determine the clinical importance of the respective PWVs in predicting the cardiovascular events. This prospective cohort study included 338 patients with essential hypertension (mean age 61.3 ± 0.7, mean follow-up period 6.5 ± 0.1 years) whose regional PWVs were measured. Primary end points were stroke, cardiovascular diseases (CVD), and death. Kaplan-Meier analysis showed that subjects with higher faPWV and baPWV had a significantly higher incidence of stroke (p = 0.0288 and 0.0277, respectively), subjects with higher hfPWV had a significantly higher incidence of CVD (p = 0.0212), subjects with higher baPWV and hfPWV had a significantly higher incidence of stroke + CVD (p = 0.0070 and 0.0463, respectively), and subjects with higher baPWV had a significantly higher mortality rate (p = 0.0367). Cox proportional hazard model revealed that baPWV was a significant risk factor for stroke + CVD after adjustment for traditional risk factors (relative risk: 14.50, p = 0.0288). Higher baPWV may be a risk factor for stroke and CVD, but the prognostic impact of regional PWVs is still unclear in patients with hypertension.