Aortic Regurgitation Left Ventricular Research Articles

Assessing Regurgitation Severity, Adverse Remodeling, and Fibrosis with CMR in Aortic Regurgitation.

Cardiac magnetic resonance (CMR) is emerging as a valuable imaging modality for the assessment of aortic regurgitation (AR). In this review, we discuss the assessment of AR severity, left ventricular (LV) remodeling, and tissue characterization by CMR while highlighting the latest studies and addressing future research needs. Recent studies have further established CMR-based thresholds of AR severity and LV remodeling that are associated with adverse clinical outcomes, and lower than current guideline criteria. In addition, tissue profiling with late gadolinium enhancement (LGE) and extracellular volume (ECV) quantification can reliably assess adverse myocardial tissue remodeling which is also associated with adverse outcomes. The strengths and reproducibility of CMR in evaluating ventricular volumes, tissue characteristics, and regurgitation severity position it as an excellent modality in evaluating and following AR patients. Advanced CMR techniques for the detection of tissue remodeling have shown significant potential and merit further investigation.

Total regurgitant fraction to predict aortic valve surgery in patients with concomitant aortic and mitral regurgitation

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Both aortic regurgitation (AR) and mitral regurgitation (MR) produce left ventricular (LV) volume overload (1). Current prognostic assessment of AR does not include the presence and magnitude of MR. Therefore, in patients with concomitant AR and MR we might be underestimating the future need of valve replacement surgery. Cardiac magnetic resonance (CMR) is a very precise tool to quantify LV volumes together with aortic and mitral regurgitant volumes. Combining data from cine and phase contrast sequences it is possible to obtain a set parameter: total regurgitant fraction (TRF). Purpose To describe the prognostic value of TRF in patients with concomitant AR and MR. Methods Patients with concomitant AR and MR with CMR studies were retrospectively recruited in three tertiary hospitals. Cases of at least moderate AR and any grade of MR were included in the analysis. Patients with indication of aortic valve surgery (symptoms, severe LV dilatation or reduced LV eyection fraction) in the moment of the CMR were excluded. Aortic regurgitant fraction (ARF) was calculated from the phase constrast data as the ratio of AR volume and LV forward volume. Mitral regurgitant Fraction (MRF) was calculated from the cine sequences as the ratio of the MR volume and the LV stroke volume (LVSV) . TRF was calculated as the ratio of mitral plus aortic regurgitant volumes and the LVSV (MRV+ARV/LVSV) Results 35 cases were analyzed, with a mean follow up period of 40 months. 9 patients developed indications of aortic valve surgery. TRF had an area under curve (AUC) to predict aortic valve surgery of 0.82, in opposite to aortic regurgitant fraction (ARF) which had an AUC of 0.75 (Figure 1) The optimum cutoff value of TRF and ARF to predict the need of surgery in our series were 38% and 27%, respectively. After 3 years of follow up 53% of patients with TRF > 38% had to be intervened (Figure 2A). In contrast, 32% of patients with ARF >27% had to be intervened (Figure 2B) Conclusion MR presence increases volume overload in patients with moderate or severe AR. TRF is a promising parameter to predict the need of aortic valve surgery in this patients

Regional Replacement and Diffuse Interstitial Fibrosis in Aortic Regurgitation: Prognostic Implications From Cardiac Magnetic Resonance

ObjectivesThis study used cardiac magnetic resonance (CMR) to assess left ventricular (LV) remodeling in chronic aortic regurgitation (AR) to identify both forms of myocardial fibrosis and examine its association with clinical outcomes. BackgroundChronic AR leads to LV remodeling, which is associated with 2 forms of myocardial fibrosis: regional replacement fibrosis that is directly imaged by late gadolinium enhancement (LGE) CMR; and diffuse interstitial fibrosis, which can be inferred by T1 mapping techniques. MethodsPatients with chronic AR who were undergoing contrast CMR with T1 mapping for valve assessment from 2011 to 2018 were enrolled. Patients with a confounding etiology of myocardial fibrosis were excluded. In addition to quantification of AR severity and LV volumetrics, LGE and T1 mapping pre- and post-contrast were performed to measure extracellular volume (ECV) and indexed ECV (iECV). Patients were followed up longitudinally to assess for the composite event of death and the need for aortic valve replacement. ResultsA total of 177 patients with isolated chronic AR were included (66% males, median age 58 years [IQR: 47.0-68.0 years]) with a median follow up of 2.5 years (IQR: 1.07-3.56 years). The iECV significantly increased with AR severity (P < 0.001), whereas ECV and replacement fibrosis did not (P = NS). On multivariate analysis, iECV remained associated with the composite event (P = 0.01). On Kaplan-Meier analysis stratified by AR regurgitant fraction (RF) and iECV, patients with AR RF severity ≥30% and iECV ≥24 mL/m2 demonstrated the highest event rate. ConclusionsAmong CMR biomarkers of fibrosis, iECV was more closely associated than replacement fibrosis or ECV with survival free of aortic valve replacement.

Abstract 13583: Left Ventricular Remodeling After Type a Aortic Dissection Surgery: a Comparison Between Different Surgical Techniques

Introduction: Type A aortic dissection (AADA) requires emergency surgery with different options including valve-sparing aortic root replacement (VSRR), supracoronary ascending aorta replacement (SCR) and aortic valve and root replacement (AVRR). Recurrence of aortic regurgitation (AR) and extent of left ventricular (LV) remodeling in patients with AADA was compared between these surgical techniques. Methods: A total of 120 patients (59 ± 12 years, 63% male) with AADA who underwent VSRR (n=22), SCR (n=62) or AVRR (n=36) were included in the present retrospective evaluation. AR grade and LV volumes and ejection fraction were assessed postoperatively (before hospital discharge) and during follow-up. Estimated marginal means ± standard error of the mean were obtained using linear mixed models. Results: Patients who underwent VSRR were significantly younger (49 ± 6 years) and more often male (84%). There were more patients in SCR group with hypertension compared to VSRR and AVRR (67% vs. 27% and 47%; p=0.006). The EuroSCORE II was highest in patients who underwent AVRR. After a median follow up of 53 months, the mean AR grade was 1.2 ± 0.2 in VSRR vs. 1.8 ± 0.2 in SCR vs. 0.2 ± 0.1 in AVRR (p&lt;0.001). LV end-diastolic and end-systolic volumes remained stable in VSRR, while a significant increase was observed in SCR (table). The ejection fraction remained stable in all groups, however, a trend towards improvement was observed in VSRR (p=0.055). Conclusions: Patients with AADA who underwent SCR experienced more AR compared to AVRR resulting in larger LV volumes during follow up. Despite higher AR grade during follow up in patients who underwent VSRR compared to AVRR; there was no deterioration in LV volumes and function after VSRR.

Stress Echocardiography in Regurgitant Valve Disease

Because of its wide availability, low cost, versatility, and clinical use, stress echocardiography has become increasingly recognized as a valuable tool in the assessment of patients with regurgitant valvular heart disease. Exercise testing is favored compared with pharmacological stress testing for risk stratification in asymptomatic patients and can identify what might otherwise be considered as a moderate valve disease. It has been shown to provide insights into exertional symptoms disproportionate to resting hemodynamics in these patients and to facilitate individual risk stratification. Aggravation of valvular regurgitation severity, exercise-induced pulmonary hypertension (PHT), impaired left ventricular (LV) contractile reserve, inducible ischemia, dynamic LV dyssynchrony, and altered exercise capacity, together with the development of symptoms during exercise echocardiography, provide the clinician with straightforward prognostic information, therefore enabling a more accurate definition of the optimal timing of intervention in patients with valvular regurgitation.1,2 In contrast, dobutamine stress echocardiography has little value in cases of valvular regurgitation. Dobutamine infusion is almost systematically associated with a decrease in the severity of regurgitation; however, it might be of interest in the detection of LV contractile reserve and inducible ischemia. The most common form of exercise used in conjunction with echocardiography is immediate postexercise imaging on a treadmill or upright bicycle ergometer. However, semisupine exercise testing on an appropriate tilted table allows continuous echocardiographic monitoring, which represents an advantageous tool for quantifying changes in valvular regurgitation severity, LV function, and pulmonary pressure (Table). This exercise stress echocardiography modality (ie, per-exercise echocardiography) is the most used in Europe, and we strongly suggest this approach in the setting of valvular heart disease to detect evanescent changes. A symptom-limited graded exercise test is recommended, and ≥80% of the age-predicted upper heart rate should be reached in the absence of symptoms. The test is adapted to the clinical conditions …

Prognostic Value of Cardiac Magnetic Resonance Imaging in Patients With Aortic Regurgitation

Guidelines on valve replacement recommend aortic valve replacement for patients with severe aortic regurgitation (AR) with symptoms or left ventricular (LV) dysfunction. However, the optimal timing of surgery for asymptomatic AR patients without LV dilation or dysfunction is not known. There are data to suggest that excess volume load imposed by AR may not only produce subclinical LV dysfunction, but produce neurohormonal activation similar to the heart failure syndrome resulting in reduced survival. The study by Myerson et al. is the first to investigate the predictive ability of cardiac MRI (CMR) for the outcome of asymptomatic patients with AR. They studied 113 asymptomatic patients with moderate-to-severe AR on echocardiography in four centers. A total of 39 (35%) patients developed symptoms or an indication for surgery over a mean follow-up period of 2.6 years. AR volume, AR regurgitant fraction, LV end-diastolic and end-systolic volumes had high discriminatory powers (area under curve of 0.96, 0.93, 0.88 and 0.78, respectively) to predict these events. Higher association with the outcome was observed when LV end-diastolic volume and regurgitant fraction were combined. A significantly higher number of patients with regurgitant fraction >33% were likely to progress to surgery compared with patients with a regurgitant fraction of <33% (85 vs 8%; p < 0.001). These results demonstrate a potential role for CMR for risk stratification of patients with asymptomatic moderate or severe AR, given the ability of CMR to accurately quantify AR and LV volumes. Based on the data presented, it is possible that we may be waiting too long to offer surgery in patients with severe AR.

Favorable Effects of Vasodilators on Left Ventricular Remodeling in Asymptomatic Patients With Chronic Moderate‐Severe Aortic Regurgitation and Normal Ejection Fraction: A Meta‐Analysis of Clinical Trials

The role of vasodilator therapy in asymptomatic patients with chronic moderate to severe aortic regurgitation (AR) and normal left ventricular (LV) function is uncertain. We assessed the effects of vasodilator therapy (hydralazine, calcium channel blockers, and angiotensin-converting enzyme inhibitors) in this subgroup of patient population. Vasodilators have favorable effects on LV remodelling in asymptomatic patients with chronic moderate to severe aortic regurgitation and normal LV function. We performed a systematic literature search for randomized clinical trials using long-term vasodilator therapy in asymptomatic patients with chronic severe AR and normal LV function. The magnitude of difference between the vasodilator and nonvasodilator groups was assessed by computing the mean difference (MD). Heterogeneity of the studies was analyzed by Cochran Q statistics. The MD for LV ejection fraction, LV end systolic volume index, and LV end diastolic volume index were computed by random effects model. The MD for LV end-systolic diameter and LV end-diastolic diameter were computed by fixed effects model. A 2-sided alpha error <0.05 was considered to be statistically significant. Seven studies with 460 patients were included. Meta-analysis of the studies revealed a significant increase in LVEF (MD: 5.32, 95% confidence interval [CI]: 0.37 to 10.26, P = 0.035), a significant decrease in LV end diastolic volume index (MD: -16.282, 95% CI: -23.684 to -8.881, P < 0.001), and a significant decrease in LV end diastolic diameter (MD: -2.343, 95% CI: -3.397 to -1.288, P < 0.001) in the vasodilator group compared with the nonvasodilator group. However, there was no significant decrease in LV end systolic volume index (MD: -6.105, 95% CI: -12.478 to 0.267, P = 0.060) or in LV end systolic diameter (MD: 0.00, 95% CI: -0.986 to 0.986, P = 1.0) in the vasodilator group compared with the nonvasodilator group. In asymptomatic patients with chronic severe AR and normal LV function, vasodilators have favorable effects on LV remodeling.

Effect of Preoperative Ejection Fraction, Left Ventricular Systolic Dimension and Hemoglobin Level on Survival After Aortic Valve Surgery in Patients With Severe Chronic Aortic Regurgitation

Surgical indications in patients with severe chronic aortic regurgitation (AR) and normal left ventricular (LV) ejection fractions (EF) remain to be established. The aim of this study was to identify prognostic indicators after surgery in patients with severe AR and normal LV systolic function. Preoperative clinical and echocardiographic characteristics were evaluated in 284 consecutive patients with chronic severe AR who underwent aortic valve surgery. Of these patients, 169 had normal (≥50%) and 115 had depressed (<50%) preoperative LV EFs. All-cause mortality was observed for a median of 39.9 months. Of 284 patients, 7 (4.4%) with normal LV EFs and 15 (12.0%) with depressed LV EFs died during follow-up after aortic valve surgery (p = 0.017). In patients with normal EFs, multivariate Cox regression analysis showed that large LV end-systolic dimension and low plasma hemoglobin level were independent predictors of postsurgical mortality. Receiver-operating characteristic analysis showed that LV end-systolic dimension ≥45 mm and hemoglobin level <13.4 g/dl were the best cut-off values for postoperative mortality. In conclusion, preoperative LV end-systolic dimension and hemoglobin level are independent prognostic factors of survival after aortic valve surgery in patients with chronic severe AR and normal LV EFs.

4.13: Non-invasive stress testing of myocardial perfusion defects: Head-to-head comparison of thallium-201 SPECT to MRI perfusion

This study evaluated the diameters and distensibility of the aortic root as well as the degree of aortic regurgitation (AR) and its effect on left ventricular (LV) function in patients 8.2 ± 3.1 years after they underwent the Ross procedure, with a comparison of these parameters between patients and matched healthy subjects.Eighteen Ross procedure patients (16 male patients, age [mean ± SD] 19.2 ± 3.8 years) and 18 matched healthy subjects (16 male patients, age [mean ± SD] 19.7 ± 4.2 years) underwent magnetic resonance imaging. Measurements for diameters (at 4 levels) and the distensibility of the aortic root were performed using a steady-state free precession sequence. Aortic flow was assessed with a velocity-encoded phase-contrast sequence. Left ventricular systolic function was assessed with a gradient-echo sequence in the short-axis plane. Comparison of parameters was performed using the Mann-Whitney U test. Correlations between diameters, distensibility, AR fraction, and LV systolic function were expressed with Spearman rank correlation coefficients. Linear regression analysis was used to identify predictors of LV systolic dysfunction.Aortic root diameters were increased in Ross procedure patients as compared with healthy subjects (mean difference 6.3-11.6 mm, P ≤ .02 at all 4 levels). Distensibility of the aortic root was lower in patients (1.9 ± 1.1 vs 7.8 ± 3.3 mm Hg−1, P < .01). An AR fraction >5% was present in 14 of the 18 patients (mean AR fraction 8% ± 5% vs 1% ± 1%, P < .01). Left ventricular ejection fraction was lower in patients (50% ± 6% vs 57% ± 6%, P < .01). Dilatation, decreased distensibility, and AR fraction were correlated with impaired LV systolic function (P < .05 for all). The AR fraction predicted impaired LV systolic function (P < .01).Magnetic resonance imaging shows dilatation and decreased distensibility of the aortic root, AR, and consequent impaired LV systolic function in patients after the Ross procedure.

Quantitative Echocardiographic Determinants of Clinical Outcome in Asymptomatic Patients With Aortic Regurgitation: A Prospective Study

The purpose of this study was to define the link between aortic regurgitation (AR) quantitation and clinical outcome in asymptomatic patients with AR.Quantitative American Society of Echocardiography (QASE) thresholds are recommended for AR assessment, but impact on clinical outcome is unknown.We prospectively enrolled (1991 to 2003) 251 asymptomatic patients (age 60 +/- 17 years) with isolated AR and ejection fraction > or =50% with quantified AR and left ventricular (LV) volumes using Doppler-echocardiography.Survival under medical management was independently determined by baseline regurgitant volume (RVol) (adjusted hazard ratio [HR] 1.22 [95% confidence interval (CI) 1.08 to 1.35] per 10 ml/beat, p = 0.002) and effective regurgitant orifice (ERO) (adjusted HR 1.52 [95% CI 1.19 to 1.91] per 10 mm(2), p = 0.002), which superseded traditional AR grading. Patients with QASE-severe AR (RVol > or =60 ml/beat or ERO > or =30 mm(2)) versus QASE-mild AR (RVol <30 ml and ERO <10 mm(2)) had lower survival (10 years: 69 +/- 9% vs. 92 +/- 4%, p = 0.05) independently of all clinical characteristics (adjusted HR 4.1 [95% CI 1.4 to 14.1], p = 0.01) and lower survival free of surgery for AR (10 years: 20 +/- 5% vs. 92 +/- 4%, p < 0.001, adjusted HR 12.9 [95% CI 5.4 to 38.5]). Cardiac events were considerably more frequent with QASE-severe versus -moderate or -mild AR (10 years: 63 +/- 8% vs. 34 +/- 6% and 21 +/- 8%, p < 0.0001). Independent determinants of cardiac events were quantitative AR grading (QASE-severe adjusted HR 5.2 [95% CI 2.2 to 14.8], p < 0.001; QASE-moderate adjusted HR 2.4 [95% CI 1.06 to 6.6], p = 0.035), which superseded traditional AR assessment (p < 0.001) and LV end-systolic volume index (ESVI) (adjusted HR 1.09 [95% CI 1.03 to 1.14 per 10 ml/m(2)], p = 0.002), which superseded LV M-mode diameters. In QASE-severe AR, patients with ESVI > or =45 versus <45 ml/m(2) had higher cardiac event rates (10 years: 87 +/- 8% vs. 40 +/- 10%, p < 0.001). Cardiac surgery for AR reduced cardiac events in patients with QASE-severe AR (adjusted HR 0.23 [95% CI 0.09 to 0.57], p = 0.002).Echocardiographic quantitation of AR severity and ESVI provides independent and superior predictors of clinical outcome in asymptomatic patients with AR and ejection fraction > or =50% and should be widely clinically applied. Patients with QASE-severe AR and ESVI > or =45 ml/m(2) should be carefully considered for cardiac surgery, which reduces cardiac events risk.

Aortic root dysfunctioning and its effect on left ventricular function in Ross procedure patients assessed with magnetic resonance imaging

Background This study evaluated the diameters and distensibility of the aortic root as well as the degree of aortic regurgitation (AR) and its effect on left ventricular (LV) function in patients 8.2 ± 3.1 years after they underwent the Ross procedure, with a comparison of these parameters between patients and matched healthy subjects. Methods Eighteen Ross procedure patients (16 male patients, age [mean ± SD] 19.2 ± 3.8 years) and 18 matched healthy subjects (16 male patients, age [mean ± SD] 19.7 ± 4.2 years) underwent magnetic resonance imaging. Measurements for diameters (at 4 levels) and the distensibility of the aortic root were performed using a steady-state free precession sequence. Aortic flow was assessed with a velocity-encoded phase-contrast sequence. Left ventricular systolic function was assessed with a gradient-echo sequence in the short-axis plane. Comparison of parameters was performed using the Mann-Whitney U test. Correlations between diameters, distensibility, AR fraction, and LV systolic function were expressed with Spearman rank correlation coefficients. Linear regression analysis was used to identify predictors of LV systolic dysfunction. Results Aortic root diameters were increased in Ross procedure patients as compared with healthy subjects (mean difference 6.3-11.6 mm, P ≤ .02 at all 4 levels). Distensibility of the aortic root was lower in patients (1.9 ± 1.1 vs 7.8 ± 3.3 mm Hg −1, P < .01). An AR fraction >5% was present in 14 of the 18 patients (mean AR fraction 8% ± 5% vs 1% ± 1%, P < .01). Left ventricular ejection fraction was lower in patients (50% ± 6% vs 57% ± 6%, P < .01). Dilatation, decreased distensibility, and AR fraction were correlated with impaired LV systolic function ( P < .05 for all). The AR fraction predicted impaired LV systolic function ( P < .01). Conclusions Magnetic resonance imaging shows dilatation and decreased distensibility of the aortic root, AR, and consequent impaired LV systolic function in patients after the Ross procedure.

Aortic Insufficiency

Major advances in the diagnostic, evaluation, and particularly surgical treatment of aortic regurgitation (AR) have redefined the role of medical treatment. In acute AR, aortic valve replacement (AVR) is the only life-saving treatment. Medical treatment may improve the hemodynamic state temporarily before surgery. Rationale of medical treatment in chronic AR is based on the natural history and pathophysiology of the disease. The primary goal is to optimize the time of the AVR. If there is any symptom and/or left ventricular (LV) dysfunction, early AVR is required. Vasodilators should only be considered as a short-term treatment before surgery if there is evidence of severe heart failure or as a long-term treatment if AVR is contraindicated because of cardiac or noncardiac factors. In asymptomatic patients with severe chronic AR and normal LV function (even if the left ventricle is moderately dilated), vasodilators may prolong the compensated phase of chronic AR, although proof of their efficacy in delaying AVR is limited. Nifedipine is the best evidence-based treatment in this indication. ACE inhibitors are particularly useful for hypertensive patients with AR. beta-Adrenoceptor antagonists (beta-blockers) may be indicated to slow the rate of aortic dilatation and delay the need for surgery in patients with AR associated with aortic root disease. Furthermore, they may improve cardiac performance by reducing cardiac volume and LV mass in patients with impaired LV function after AVR for AR.

Aortic Regurgitation.

Left ventricular (LV) systolic function is an important determinant of long-term prognosis in patients with chronic aortic regurgitation (AR). Impaired LV systolic function identifies a group of patients who are at risk of developing postoperative congestive heart failure and death after aortic valve replacement (AVR). Hence, asymptomatic patients with definite evidence of impaired LV function should undergo operation without waiting for the development of symptoms or more severe LV dysfunction. Among asymptomatic patients with normal LV systolic function (normal ejection fraction), prognosis is excellent, and fewer than 5% per year require surgery because of symptom development or LV dysfunction. Patients likely to require surgery can be identified on the basis of age, severity of LV dilatation, and progressive increase in LV dimensions or decrease in resting ejection fraction during the course of serial follow-up studies. Afterload-reducing therapy in asymptomatic patients with severe AR and normal LV function has beneficial hemodynamic effects; chronic therapy may reduce the likelihood of symptoms or LV systolic dysfunction. Aortic valve replacement should be performed once significant symptoms develop. In the absence of important symptoms, the operation should also be performed in patients with AR who manifest consistent and reproducible evidence of either LV contractile dysfunction at rest or extreme LV dilatation. Noninvasive imaging should play a major role in evaluation. An important clinical decision--such as recommending AVR in the asymptomatic patient--should not be based on a single echocardiographic or radionuclide angiographic measurement. When these data consistently indicate impaired contractile function at rest or extreme LV dilatation on repeat measurement, however, operation is indicated in the asymptomatic patient. This strategy should reduce the likelihood of irreversible LV dysfunction in these patients and enhance long-term postoperative survival.

Comparison of effects of isometric and supine bicycle exercise on left ventricular performance in patients with aortic regurgitation and normal ejection fraction at rest

The effects of handgrip and supine bicycle exercise on hemodynamics and left ventricular (LV) performance were compared in 25 patients with moderate to severe aortic regurgitation (AR) and normal LV ejection fraction at rest (≥ 50%) and in 10 control subjects. In both groups, heart rate, systolic blood pressure, rate-pressure product, and LV output were higher during supine bicycle exercise. Compared with the controls, in patients with AR, stroke volume was unchanged during supine bicycle exercise. LV end-diastolic volume increased during handgrip exercise but was unchanged during supine bicycle exercise. LV end-systolic volume increased and ejection fraction decreased during both forms of exercise. Of 25 patients with AR, 15 (60%) during handgrip exercise and 19 (76%) during supine bicycle exercise had an abnormal ejection fraction response ( p < 0.05). In patients with moderate to severe AR and normal LV ejection fraction at rest, both handgrip and supine bicycle exercise induced LV dysfunction. An abnormal LV ejection fraction response occurred more often with supine bicycle exercise. Handgrip exercise may be a useful alternative method for detecting LV dysfunction in patients with AR in whom adequate bicycle exercise cannot be accomplished.