Before and after Endovascular Aortic Repair in the Same Patients with Aortic Dissection: A Cohort Study of Four-Dimensional Phase-Contrast Magnetic Resonance Imaging

(1) Background: We used four-dimensional phase-contrast magnetic resonance imaging (4D PC-MRI) to evaluate the impact of an endovascular aortic repair (TEVAR) on aortic dissection. (2) Methods: A total of 10 patients received 4D PC-MRI on a 1.5-T MR both before and after TEVAR. (3) Results: The aortas were repaired with either a GORE TAG Stent (Gore Medical; n = 7) or Zenith Dissection Endovascular Stent (Cook Medical; n = 3). TEVAR increased the forward flow volume of the true lumen (TL) (at the abdominal aorta, p = 0.047). TEVAR also reduced the regurgitant fraction in the TL at the descending aorta but increased it in the false lumen (FL). After TEVAR, the stroke distance increased in the TL (at descending and abdominal aorta, p = 0.018 and 0.015), indicating more effective blood transport per heartbeat. Post-stenting quantitative flow revealed that the reductions in stroke volume, backward flow volume, and absolute stroke volume were greater when covered stents were used than when bare stents were used in the FL of the descending aorta. Bare stents had a higher backward flow volume than covered stents did. (4) Conclusions: TEVAR increased the stroke volume in the TL and increased the regurgitant fraction in the FL in patients with aortic dissection.

Prognostic Value of Complementary Echocardiography and Magnetic Resonance Imaging Quantitative Evaluation for Isolated Tricuspid Regurgitation

Background: Isolated tricuspid regurgitation (TR) remains a management dilemma with poor outcomes. Echocardiography and cardiac magnetic resonance imaging (CMR) are valuable tools for evaluating TR, but their prognostic utility has rarely been studied together in this setting. We aimed to determine the prognostic value and thresholds for echocardiography and CMR parameters for isolated severe TR. Methods: Consecutive patients with isolated severe TR by echocardiography and undergoing CMR during January 2007 to June 2019 were studied. Echocardiography and CMR-derived quantitative parameters were analyzed for independent associations with and thresholds for predicting the primary end point of all-cause mortality during follow-up. Results: Among 262 patients studied, mean age was 62.8±15.6 years, 156 (59.5%) were females, 207 (79.0%) had secondary TR, and 87 (33.2%) underwent tricuspid valve surgery after CMR. There were 68 (26.0%) deaths during a mean follow-up of 2.5 years. Both CMR-derived tricuspid regurgitant fraction (per 5% increase) and right ventricle free wall longitudinal strain (per 1% decrease in magnitude) were independently associated with worse survival, with hazard ratios (95% CIs) of 1.15 (1.05–1.25) and 1.10 (1.04–1.17), respectively, along with right heart failure symptoms of 2.03 (1.14–3.60), while tricuspid valve surgery was borderline protective with 0.55 (0.31–0.997). Regurgitant fraction ≥30%, regurgitant volume ≥35 mL and right ventricle free wall longitudinal strain ≥−11% (by velocity vector imaging technique, which yields lower magnitude values than other conventional strain techniques) were the optimal thresholds for mortality during follow-up. Conclusions: TR quantification by CMR and right ventricle free wall longitudinal strain by echocardiography were the key imaging parameters independently associated with reduced survival in isolated TR, incremental to conventional clinical factors. Clinically significant thresholds for these parameters were determined and may help guide decision-making for TR management.

Aortic and mitral flow quantification using dynamic valve tracking and machine learning: Prospective study assessing static and dynamic plane repeatability, variability and agreement

Background Blood flow is a crucial measurement in the assessment of heart valve disease. Time-resolved flow using magnetic resonance imaging (4 D flow MRI) can provide a comprehensive assessment of heart valve hemodynamics but it relies in manual plane analysis. In this study, we aimed to demonstrate the feasibility of automate the detection and tracking of aortic and mitral valve planes to assess blood flow from 4 D flow MRI. Methods In this prospective study, a total of n = 106 subjects were enrolled: 19 patients with mitral disease, 65 aortic disease patients and 22 healthy controls. Machine learning was employed to detect aortic and mitral location and motion in a cine three-chamber plane and a perpendicular projection was co-registered to the 4 D flow MRI dataset to quantify flow volume, regurgitant fraction, and a peak velocity. Static and dynamic plane association and agreement were evaluated. Intra- and inter-observer, and scan-rescan reproducibility were also assessed. Results Aortic regurgitant fraction was elevated in aortic valve disease patients as compared with controls and mitral valve disease patients ( p < 0.05). Similarly, mitral regurgitant fraction was higher in mitral valve patients ( p < 0.05). Both aortic and mitral total flow were high in aortic patients. Static and dynamic were good (r > 0.6, p < 0.005) for aortic total flow and peak velocity, and mitral peak velocity and regurgitant fraction. All measurements showed good inter- and intra-observer, and scan-rescan reproducibility. Conclusion We demonstrated that aortic and mitral hemodynamics can efficiently be quantified from 4 D flow MRI using assisted valve detection with machine learning.

Long-term outcome after transcatheter mitral annuloplasty for secondary mitral regurgitation

Funding Acknowledgements Type of funding sources: None. Background The long-term effects of transcatheter mitral valve annuloplasty (TMVA) for secondary mitral regurgitation is unknown. Purpose We studied the clinical outcome and the effects on left ventricular (LV) function and remodeling and on mitral regurgitation (MR) severity after TMVA using the Carillon annuloplasty device. Methods We analyzed 33 consecutive patients with symptomatic MR who were treated with TMVA at Leipzig University Hospital between 2012 and 2018. Echocardiography was performed before TMVA and at follow-up. MR severity was quantitatively assessed by regurgitant volume (calculated as LV total stroke volume – LV forward stroke volume) and regurgitant fraction (calculated as regurgitant volume / LV total stroke volume). Results Mean age was 80 ± 10 years, 19 patients were women. A Society of Thoracic Surgeons (STS) score of 8.1 ± 7.2% indicated high risk status for mitral valve surgery. In 26 patients, mitral regurgitation resulted from LV remodeling and LV dysfunction, 7 suffered from left atrial dilatation. LV ejection fraction at baseline was 38% (30-49%; median, interquartile range). During a mean follow-up time of 45 ± 20 months, 17 patients died, 2 patients withdraw consent, and 4 patients were lost. Of the remaining patients, 4 were hospitalized for decompensated heart failure, and 2 underwent additional transcatheter edge-to-edge mitral valve repair. At follow-up, NYHA functional class improved from 95% in class III/IV at baseline to 70% in class I/II with no patients in NYHA class IV (p &lt; 0.0001). Mitral regurgitant volume was reduced from 27mL (25-42mL) to 8mL (3-17mL) (p = 0.035) and regurgitant fraction from 43% (32-54%) to 11% (8-24%) (p = 0.020). LV end-diastolic volume index (92mL/m2 (71-107mL/m2) vs. 67mL/m2 (46-101mL/m2), p = 0.084) and end-systolic volumes index (51mL/m2 (44-69mL/m2) vs. 32mL/m2 (20-53mL/m2), p = 0.037) decreased. Thus, total stroke volume remained similar (38mL/m2 (33-43mL/m2) vs. 33mL/m2 (26-44mL/m2), p = 0.695) while LV ejection fraction increased (43% (31-49%) vs. 54% (46-57%), p = 0.032). Forward stroke volume, heart rate and forward cardiac output remained unchanged. Blood pressure was similar at baseline and at follow-up. Conclusion. Among high risk patients undergoing transcatheter mitral valve annuloplasty for symptomatic secondary MR, mortality was about 50% at 4 years. In the surviving patients, reduced MR severity was associated with fewer heart failure symptoms, reverse LV remodeling and improved LV function.

A comparison of the clinical efficacy of echocardiography and magnetic resonance for chronic aortic regurgitation

Aims Timing surgery in chronic aortic regurgitation (AR) relies mostly on echocardiography. However, cardiac magnetic resonance (CMR) may be more accurate for quantifying regurgitation and left ventricular (LV) remodelling. We aimed to compare the technical and clinical efficacies of echocardiography and CMR to account for the severity of the disease, the degree of LV remodelling, and predict AR-related outcomes. Methods and results We studied 263 consecutive patients with isolated AR undergoing echocardiography and CMR. After a median follow-up of 33 months, 76 out of 197 initially asymptomatic patients reached the primary endpoint of AR-related events: 6 patients (3%) were admitted for heart failure, and 70 (36%) underwent surgery. Adjusted survival models based on CMR improved the predictions of the primary endpoint based on echocardiography: R2 = 0.37 vs. 0.22, χ2 = 97 vs. 49 (P &lt; 0.0001), and C-index = 0.80 vs. 0.70 (P &lt; 0.001). This resulted in a net classification index of 0.23 (0.00–0.46, P = 0.046) and an integrated discrimination improvement of 0.12 (95% confidence interval 0.08–0.58, P = 0.02). CMR-derived regurgitant fraction (&lt;28, 28–37, or &gt;37%) and LV end-diastolic volume (&lt;83, 183–236, or &gt;236 mL) adequately stratified patients with normal EF. The agreement between techniques for grading AR severity and assessing LV dilatation was poor, and CMR showed better reproducibility. Conclusions CMR improves the clinical efficacy of ultrasound for predicting outcomes of patients with AR. This is due to its better reproducibility and accuracy for grading the severity of the disease and its impact on the LV. Regurgitant fraction, LV ejection fraction, and end-diastolic volume obtained by CMR most adequately predict AR-related events.

Outcomes in severe tricuspid regurgitation by CMR: when severe is too severe

Introduction Tricuspid regurgitation (TR) is related to poor prognosis independently of the etiology. Recently a new scale classification has been proposed to better characterize the grading of more than severe TR. Massive and torrential TR seem to have worse prognosis based on recent echocardiographic studies. There is no information on how that classification would apply when TR is quantified by cardiac magnetic resonance (CMR). Purpose To define the cut-off value of massive and torrential TR by CMR and to investigate its potential prognostic implications. Methods Consecutive patients in stable clinical status with significant TR evaluated in the Heart Valve Clinic with a contemporaneous echo and CMR were included. TR severity was evaluated by biplane vena contracta and effective regurgitant orifice method, using EPIQ system and by TR regurgitant fraction using a 1.5 Tesla CMR Philips scanner. End-point included cardiovascular mortality, tricuspid valve surgery or heart failure. Results A total of 56 patients were included (mean age was 72±9 years, 74% females). According to echocardiography n=43 (76%) were severe TR, n=8 (14%) were massive IT and n=5 (9%) were torrential TR. Patients with massive and torrential TR showed higher RV end-diastolic volume and lower RVEF. A TR regurgitant fraction (TRF) &gt;50% held the best accuracy to define massive / torrential TR. During a median follow up of 2.4 years (IQR: 1.1–3.3 years) 31% of the patients reached the combined endpoint. TR regugitant fraction was predictive of worse prognosis (hazard ratio per 1%TRF=1.085 [1.024–1.150] p=0.003). Patients with a massive and torrential TR showed a significantly higher rate of events (figure). Figure shows on the left (A) spline curves displaying survival free of events for each value of TR regurgitant fraction. y-axis represents the hazard ratio regurgitation fraction (green line) and 95% confidence interval (shadow). On the right (B) Kaplan Meier curves show a significantly higher rate of events in patients with RF&gt;50%. Conclusions Our results confirm that patients with massive/torrential TR are populations at higher risk of cardiovascular events. New classification scheme may be included in CMR grading scales. Further research will establish who may benefit the most of intensive therapeutic treatments and intervention on the tricuspid valve. Funding Acknowledgement Type of funding source: None

Regurgitant fraction as a load-dependent parameter in tricuspid regurgitation quantitation

Background Regurgitant fraction (RF) is an accepted tool for valvular lesion quantitation in the left heart, while its role in tricuspid regurgitation (TR) is less studied. Purpose The aim of this study was to examine the determinants of RF in TR and its diagnostic utility for TR severity grading in comparison with regurgitant volume (RVol) using guideline recommended integrated algorithm as the reference standard. Methods 114 pts with more-than-mild TR in the absence of pulmonary regurgitation or intracardiac shunt prospectively underwent 2D and 3D transthoracic echocardiography. 3D data sets of the right ventricle (RV) were obtained during breath hold. 3D RVol was calculated through subtracting the right ventricular outflow tract forward stroke volume (SV) from RV SV, where the outflow tract cross-sectional area was derived from single-view measured diameter. 3D RF was calculated by dividing 3D RVol with RV SV. 3D EROA was derived dividing 3D RVol with the velocity-time integral of TR. Results 104 pts were included in the final analysis. 3D RF correlated well with 3D RVol (r=0.80, P&lt;0.0001). Factors encompassing aetiology (organic/functional), heart rate, systolic pulmonary arterial pressure (sPAP), cardiac output, 3D EROA and RV end-diastolic volume index were included in multiple linear regression (R2=0.85), which demonstrated that RF was associated with sPAP (P&lt;0.0001) but not RV end-diastolic volume index (P=0.116). Receiver operator characteristic analysis revealed significant difference in area under the curve between 3D RVol and 3D RF (Z=2.873, P=0.004). Such difference diminished in pts with elevated sPAP (Z=1.226, P=0.220), while remained in those with normal range sPAP (Z=2.897, P=0.004). Conclusions 3D RF is less dependent on volume load but is significantly influenced by pressure load in TR quantitation. The diagnostic power of 3D RF in differentiating severe TR is comparable with 3D RVol in pts with elevated sPAP but is limited in pts with normal range sPAP. Funding Acknowledgement Type of funding source: None

Relationship between aortic distensibility and aortic regurgitation depending on aortic valve anatomy. A CMR study

Background Aortic regurgitation (AR) can be evaluated by cardiac magnetic resonance (CMR).The most commonly used method to quantify AR is direct measurement using phase contrast (PC) imaging, at the aortic root (as close as possible to the aortic valve), for the calculation of regurgitant fraction (RF). Aortic distensibility (AD) may affect aortic valve dynamics and, as a result, aortic regurgitation grade. However, the impact of aortic distensibility in this evaluation remains unknown. Purpose The aim of the study was to evaluate the relationship between AD and AR in patients with different aortic valve anatomy. Methods 213 patients with different AR severity grades and aortic valve anatomy (tricuspid (TAV) and bicuspid valve (BAV) patients) were enrolled (32.2% female, 74% BAV, 55.5±15.4 years), excluding connective tissue disease. All patients underwent a CMR study with PC sequences for the evaluation of regurgitant fraction at the aortic valve level. AR was considered as mild (&lt;15%), moderate (15–30%) or severe (&gt;30%) depending on RF value. Furthermore we used cine-sequences to estimate aortic diameters and distensibilities, using Art Fun software. Distensibility was calculated as (change in aortic area between systole and diastole/diastolic area)/brachial pulse pressure. Results 159 (73.7%) AR were mild, 30 (14.1%) moderate and 24 (11.3%) severe. RF significantly correlated with aortic root diameter (r=0.337, p&lt;0.001) and did not correlate with AD at the level of proximal descending aorta (r=0.121 and p=0.107). Furthermore descendig aorta distensibility correlated with age (r=−0.631, p&lt;0.001) and aortic root diameter (r=−0.224, p=0.002). Dividing population in two different groups, depending on aortic valve anatomy, in TAV patients RF continued to not correlate with AD (r=0.159, p=0.369). In contrast, RF in BAV patients was positively correlated with AD (r=0.223, p=0.007) even after adjustment for aortic diameter and age in a multiple regression model (p&lt;0.001, R2=0.478). Conclusions In our study, aortic regurgitation is positively related to descending aorta distensibility in BAV patients, regardless of age and aortic root diameter. Thus, AD may play a role in the evaluation of AR in case of bicuspid valves. In contrast, in TAV patients, distensibility does not seem to influence the assessment of AR severity. Descending aorta distensibility Funding Acknowledgement Type of funding source: Other. Main funding source(s): Research grant provided by the Cardiopath PhD program

Proportionate or disproportionate secondary mitral regurgitation: how to untangle the Gordian knot?

Recent randomised percutaneous mitral intervention trials in patients with heart failure with secondary mitral regurgitation (SMR) have yielded contrasting results. A ‘relative load’ or ‘proportionality’ conceptual framework for SMR has been proposed to partly explain the disparate results. The rationale behind the framework is that SMR depends on the left ventricular dimension and not vice versa. In this review, we provide an in-depth analysis of the proportionality parameters used in this framework and also discuss the regurgitant fraction. We also consider haemodynamic observations in SMR that may affect the interpretation and comparisons among proportionality parameters. The conclusion is that the proportionality concept remains hypothetical and requires prospective validation before envisaging its use at individual patient level for risk stratification or therapeutic decision-making.