Aortic Valve Plane Research Articles

Commissural misalignment independently predicts leaflet thrombosis after transcatheter aortic valve implantation.

Transcatheter aortic valve implantation (TAVI) has become a minimally invasive alternative to surgical aortic valve replacement. Hypo-attenuated leaflet thickening (HALT)-a marker of subclinical leaflet thrombosis commonly detected by cardiac computed tomography (CT) after TAVI-may influence valve durability and function. The purpose of this study was to compare commissural alignment of the native and prosthetic aortic valves in cardiac CT in subjects with and without HALT and thereby identify commissural misalignment as potential predictor for leaflet thrombosis after TAVI. In 170 subjects, 85 with and 85 without HALT in post-TAVI CT, commissural orientation of the prosthesis was determined comparing native and prosthetic aortic valve orientation in cardiac CT by measuring the commissural angle relative to the right coronary ostium in the aortic valve plane. For the prosthetic valve, any deviation ≤ 15° compared to the native valve was classified as "aligned"; 16-30° as "mild", 31-45° as "moderate" and ≥ 45° as "severe" misalignment. Among subjects with HALT, median angular deviation was higher (36°, IQR 31°) than in the control group (29°, IQR 29°, p = 0.042). "Severe" misalignment was more frequent in subjects who developed HALT (n = 31, 37%) compared to the control group (n = 17, 20%, p = 0.013). In logistic regression analysis, more severe deviation (p = 0.015, OR = 1.02 per 1° deviation) and "severe" misalignment (p = 0.018, OR = 2.2) represented independent predictors for the occurrence of HALT after TAVI. Subclinical leaflet thrombosis after TAVI is associated with commissural misalignment. Potential clinical advantages of obtaining commissural alignment remain to be systematically assessed.

520 AN UNEXPECTED SURPRISE

Abstract Aortic Pseudoaneurysms often represent a complication of reconstructive surgery of the aortic valve and ascending aorta due to dehiscence of the surgical suture, especially in correspondence of reimplanted coronary ostia. We present the case of a 74-year-old patient with a recent feverish episode and positive blood cultures for Serratia marcescens, who came to our attention to perform a transesophageal echocardiogram for suspected endocarditis. In history, previous aortic valve replacement with biological prosthesis about 6 months before, complicated by pseudoaneurysm of the ascending aorta caused by dehiscence of sutures, treated by pseudoaneurismectomy and reconstruction of aortic continuity. Transesophageal echo showed a normopositioned bioprosthesis in the aortic location and absence of formations compatible with vegetations. During the examination, a subtle drop-out of echoes in the anterior wall of the ascending aorta was observed at approximately 2 cm from the aortic valve plane, raising suspicion of communication with a large pseudoaneurysmal sac. The Colordoppler showed a jet of discrete turbulence between the two cavities; for these reasons it was indicated to perform an urgent angioTC, which documented the presence of fissuring of the proximal ascending aorta with active overflow of contrast media with a collar of about 12 mm and considerable blood collection in the anterior mediastinum of about 51×38×60mm. The patient underwent false lumen exclusion surgery by percutaneous amplatzer device placement. Currently, the patient is asymptomatic and in good clinical condition.

P331 IMPLANT OF THE BALLOON EXPANDABLE BIOLOGICAL PROSTHESIS FOR TAVI (EDWARDS SAPIEN 3 ULTRA) PRE–ASSEMBLED ON EXPANSION BALLOON, IN “OPEN” SITUATION WITH PATIENT IN CEC

Abstract The biological valve prostheses malfunctioning often leads to severe forms of heart failure, whose treatment requires surgical or percutaneous re–intervention. We report the case of a 77–year–old man with a biological aortic prosthesis since 2009 (Elan stentless–21), hospitalized for acute cardiac decompensation related to severe aortic prosthetic insufficiency (likely infective endocarditis with periprosthesis abscess involving the perivalvular fibrous lamina) and coexistence of severe mitral insufficiency. After 25 days of therapy, in stable haemodynamic conditions, surgery was scheduled to replace the aortic prosthesis and the mitral valve, in CEC. The exposure of the aortic valve plane highlighted the rupture of the prosthetic coronary cusp in the absence of prosthetic detachment and perivalvular abscess. After removal of the degenerated cusps, the preparation and implantation of the new biological prosthesis (perimount–Magna–19) was hindered by the excessive presence of calcium–fibrosis in the suture site of the valve ring which did not allow adequate sealing, with multiple peri–prosthetics leaks; the possibility of sutureless prostheses implantation was made impossible by lack of adequate anatomical conditions. In these conditions, the possibility of implanting a biological prosthesis for TAVI, pre–mounted on the expansion balloon (Ewards–Sapien3–Ultra–23mm), in an “open” situation and in CEC, was considered. The implantation of the balloon–expandable prosthesis was performed with direct vision of the aortic annulus and coronary ostia; the insertion of the prosthesis was performed on a standard “J” guide wire positioned in the ventricle; the expansion of the prosthesis was performed in two balloon inflation steps. The intraoperative ecotransophageal echo demonstrated the correct positioning of the biological aortic prosthesis with minimal periprosthetic leak. The presence of severe residual mitral insufficiency suggested a replacement of the mitral valve with biological prosthesis. On day 4 the patient was clinically stable; the transesophageal echocardiogram showed normal functioning of the prostheses. The direct implantation of the expandable biological prosthesis in the cardiac surgery room, in “open” and CEC, after excluding active endocarditic processes and infectious complications, allowed the implantation of a larger prosthesis and to avoid significant perivalvular leaks.

Aortic Valve Calcification Score in Patients with Arterial Hypertension Environmentally Exposed to Tobacco Smoke

The objective of our study was to determine the relationship between exposure to environmental tobacco smoke (ETS) and the value of the aortic valve calcification score (AVCS) in people suffering from arterial hypertension (AH). 107 non-smokers with AH (mean age 67.16 ± 8.48 years) were qualified for the study. The degree of exposure to ETS was assessed using the Second-hand Smoke Exposure Scale (SHSES) questionnaire. Study group was divided depending on ETS exposure: A—no exposure, B—low, C—medium and D—high. AVCS was measured based on the aortic valve plane multiplanar reconstruction from the non-contrast phase of the cardiac computed tomography. The Agatston algorithm was used, in which calcifications were considered changes with a density exceeding 130 HU. The mean AVCS value in the study group of patients was 213.59 ± 304.86. The AVCS was significantly lower in subgroup A than in subgroups C and D. In subgroup A, the lack of aortic valve calcification (AVCS = 0) was observed significantly more frequently than in subgroups C and D. There was a positive correlation between the number of SHSES points and the AVCS value (r = 0.37, p < 0.05). Based on the ROC curve, the SHSES value was determined as the optimal cut-off point for the prediction of AVCS = 0, amounting to 3 points. The accuracy of SHSES < 3 as the predictor of AVCS = 0 was set at 62.18%. Hypertensive patients have an unfavourable relationship between the amount of exposure to ETS, determined on the SHSES scale, and the AVCS value.

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

BackgroundBlood 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.MethodsIn 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.ResultsAortic 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.ConclusionWe demonstrated that aortic and mitral hemodynamics can efficiently be quantified from 4 D flow MRI using assisted valve detection with machine learning.

P349 Utility and prognostic value of aortic valve area by magnetic resonance imaging in patients with aortic stenosis

Abstract Classically clinical evaluation of patients with aortic stenosis (AS) is made using clinical and echocardiographic parameters but recently new imaging techniques as cardiovascular magnetic resonance (CMR ) are being used increasingly in this clinical setting. We aim to assess utility and prognostic value of aortic valve area (AVA) by CMR in patients with AS regarding echocardiographic data. METHODS a retrospective cohort of patients with AS referred to CMR and cardiac echocardiography study for evaluation were included. Patients with known coronary artery disease or another significant valve disease were excluded. Clinical Follow up was performed to asses cardiovascular death, hospital admission or aortic valve replacement at the first year after imaging evaluation. Furthermore symptomatic status was assessed. Echocardiographic severity was estimated used peak and mean gradients . Additionally a CMR study including b-SSFPS for left ventricle ejection fraction (LVEF) quantification and phase-contrast sequences acquired at aortic valve plane to analyze aortic valve area (AVA) by planimetry was performed. RESULTS ninety eight patients, mean age 67+ 15 years, 52(58%) males, 23 (25%) with decreased left ventricular ejection fraction. A significant negative correlation was observed between AVA by CMR and echocardiographic gradients ( -0.49 for mean gradient and -0.58 for peak gradient). AVA was strongly associated to symptomatic status (AUROC curve 0.66, p &amp;lt; 0.001). A multivariate logistic regression model including echocardiographic gradients,CMR, LVEF and AVA was performed and mean gradient ( OR:1.02 p = 0.01) and AVA (OR: 0.002 p = 0.001) were shown to be independent predictors of events. Conclusion 1.AVA by planimetry in phase-contrast CMR sequences is a valid tool to asses severity of aortic valve stenosis . 2 AVA was strongly associated to symptomatic status.3. AVA has proven to have additional prognostic value beyond echocardiographic gradients. Abstract P349 Figure. Aortic valve area by planimetry by MR

P3654Location of the coronary origins in transposition patients following anatomical repair: Implications for invasive coronary angiography and intervention

Abstract Background Surgical repair of transposition of the great arteries (TGA) is most commonly via the arterial switch operation (ASO). This involves translocation of the aorta and pulmonary trunk, typically with anastomosis of the branch pulmonary arteries anteriorly (LeCompte manoeuvre) and re-implantation of the coronary arteries onto the posterior neo-aorta. As such, the position of the coronary ostia may differ from their expected locations. Purpose To use ECG-gated CT angiography to describe the anatomic position of coronary ostia in post-switch TGA patients guiding potential catheter interventions in this population. Methods All post ASO patients who underwent CT imaging between 2008–2018 were identified. Patients with complex anatomy such as double outlet right ventricle were excluded. The positions of the coronary ostia were measured in degrees from vertical on a double-oblique reconstruction in the aortic valve plane. Ostium positions were compared to those of patients with no congenital heart disease via Watson's two-sample test of homogeneity for circular data. Angular dispersion was compared between groups via the Wallraff test. P&lt;0.05 indicated statistical significance. Results Of 206 adult patients with TGA and ASO followed in our adult congenital heart disease centre, 38 (18.4%) had CT imaging available for analysis during the study period (mean age 24±6.8, 75% male). The control group consisted of 15 patients investigated for chest pain (mean age 54±15.1, 73% male). In the control group, the right and left coronary ostia arose at a mean angle of −19 and +125 degrees from vertical (figure 1a). This was significantly different to the mean ASO coronary ostia clustered at mean angles of −70 and +29 degrees from vertical (Watson p&lt;0.001) (figure 1b, with stenosis at the left coronary anastomosis). There was no significant difference in spread of left ostia (Rho 0.9 vs 0.99, p=0.12), but right ostia were significantly more variable in ASO patients than controls (0.71 vs 0.96, p=0.003). Figure 1 Conclusions Coronary ostial positions in the neo-aorta of post-ASO patients differ significantly from those of normal controls, with considerable variability, especially in right coronary position. CT can demonstrate coronary ostia in 3D space and derive appropriate tube angles to guide catheterisation in post-operative congenital cardiac patients, optimise catheter selection, reduce catheterisation tome, radiation and contrast dose.

Three Dimensional Coordinate Methodology to Determine Impella Device Positioning and Potential Impact on Mitral Regurgitation

Impella devices provide temporary mechanical circulatory support by means of a catheter based system with a microaxial rotor pump to establish continuous flow from the inflow port (IP) in the left ventricle to the outflow port in the aorta. The device has a large degree of mobility. Initial placement and repositioning are typically guided with two dimensional echocardiography, (2DE) using the parasternal long axis view (PLAX). The user's manual suggests placement of the device such that the inflow port is 3-4cm below the aortic valve (AV). This recommendation does not directly address the importance of the inflow port's position relative to the mitral apparatus. We developed a novel methodology to better quantify Impella position and assess its impact on the mitral valve. We analyzed 21 echocardiograms of patients with Impella devices in the left ventricle that had adequate 3DE images as well as assessment of MR. We used the AV and mitral valve (MV) coaptation points to establish a cylindrical coordinate system to map the device as it “travels” through the ventricle (Fig. 1). Using these points as landmarks, we were able to quantify the device's position relative to key anatomical structures. Z is the distance measured from the AV plane at the “origin”. The plane defined by theta is oriented such that the vertical axis (corresponding to π and 3/2π) bisects the aortic valve and the mitral valve. Using a full 360° range as opposed to a symmetrical 180° system provides coordinate data that can distinguish between lateral and septal facing positions. Employing this coordinate data, we compared these positions to degree of MR (acquired from the study report). Results: The majority of devices were positioned such that the IP was in Q4 or Q3 (12/21 and 7/21, respectively, Fig. 2). In two groups stratified by severity of MR, moderate to severe & none to mild, we found that distance between the IP and the MV was shorter in the moderate-severe group (umoderate-severe=.84cm, unone-mild=1.5cm; Student's T p=0.028, 1-tailed; Fig. 4). Conclusions: This novel methodology appears to provide a more robust quantitative analysis of the 3D positioning of the Impella IP. Proximity of the IP to the MV is associated with MR.

When it pops-out: Restart all over again from the beginning?

An 82-year-old female with a severe aortic stenosis (AS) and a history of acute decompensated heart failure was scheduled for TAVR. A stiff wire accidentally dislodged from the left ventricle before delivering an S3 valve to the aortic valve plane. A successful S3 implantation was achieved by crossing a regular wire using the flex wheel of the delivery system handle to align the nose cone with the aortic orifice followed by an exchange to a stiff wire. This is the very first clinical case report of this technique for a possible bailout procedure during a premature LV guidewire dislodgement, which significantly reduces additional risk, procedural time and cost.

Application of cryoenergy to improve septal exposure during transaortic septal myectomy in hypertrophic obstructive cardiomyopathy.

For the past few decades, the transaortic septal myectomy (Morrow's procedure) has been the gold standard for treating severe left ventricular outflow tract obstruction in hypertrophic obstructive cardiomyopathy (HOCM) patients. 30-day mortality has been reported at less than 1% in dedicated centers. However, in a subgroup of patients, the interventricular septal obstruction is localized very distally, below the aortic valve plane, and the transaortic approach can be very challenging. A subset of these patients can present with residual obstruction after surgery, due to inadequate length of septal excision, leading to reoperation. The aim of this work is to illustrate an original application of cryoenergy to improve the transaortic exposure of the interventricular septum and thus enable surgeons to perform very distal myectomies in HOCM patients.

Balloon Valvuloplasty to Predict X-ray Projection Angles that are Perpendicular to Cardiovascular Structures: A TAVI Patient Feasibility Study.

The purpose of this work is to describe methods to measure the 3D angular orientation of cardiovascular structures based on a planar image of a valvuloplasty balloon. These methods facilitate X-ray beam alignment with respect to the anatomy of interest. X-ray beam projections which are perpendicular to the long axis of cardiovascular structures are required to support interventional procedures, including transcatheter aortic valve implant (TAVI). During the TAVI procedure, the 3D angular orientation of the LVOT of 10 patients was measured from a single planar image of an aortic valvuloplasty balloon and the continuous range of X-ray projection angles which are aligned with the aortic valve plane were calculated (research method). Misalignment of the X-ray beam and TAVI valve frame was measured from images of the deployed valve. The accuracy of the research method was compared to clinical standard method to determine appropriate X-ray projection angles, which utilized CT and aortography. Using the clinical standard method, the median misalignment of the X-ray beam and TAVI valve frame was 8.6° (range 2.6° to 21°). Misalignment was reduced to 2.5° (range 0° to 10°) using the research method. The 3D angular orientation of cardiovascular structures can be measured accurately from a single X-ray projection image of a known cardiovascular device contained within the anatomy of interest. For TAVI procedures, improved X-ray beam alignment may help facilitate procedural success. © 2016 Wiley Periodicals, Inc.

Anterior Aortic Plane Systolic Excursion: A Novel Indicator of Transplant-Free Survival in Systemic Light-Chain Amyloidosis

Anterior aortic plane systolic excursion (AAPSE) was evaluated in the present pilot study as a novel echocardiographic indicator of transplant-free survival in patients with systemic light-chain amyloidosis. Eighty-nine patients with light-chain amyloidosis were included in the post-hoc analysis. A subgroup of 54 patients with biopsy-proven cardiac amyloid infiltration were compared with 41 healthy individuals to evaluate the discriminative ability of echocardiographic findings. AAPSE is defined as the systolic excursion of the anterior aortic margin. To quantify AAPSE, the M-mode cursor was placed on the aortic valve plane in parasternal long-axis view at end-diastole. Index echocardiography had been performed before chemotherapy. Median follow-up duration was 2.4years. The primary combined end point was heart transplantation or overall death. Mean AAPSE was 14±2mm in healthy individuals (mean age=57±10years; 56% men; BMI=25±4kg/m2). AAPSE<11mm separated patients from age-, gender-, and BMI-matched control subjects with 93% sensitivity and 97% specificity. Median transplant-free survival of patients with AAPSE<5mm was 0.7 versus 4.8years (P=.0001). AAPSE was an independent indicator of transplant-free survival in multivariate Cox regression (echocardiographic model: hazard ratio=0.72 [P=.03]; biomarker model: hazard ratio=0.62 [P=.0001]). Sequential regression analysis suggested incremental power of AAPSE as a marker of transplant-free survival. An ejection fraction-based model with an overall χ2 value of 22.8 was improved by the addition of log NT-proBNP (χ2=32.6, P<.005), troponin-T (χ2=39.6, P<.01), and AAPSE (χ2=54.0, P<.0001). AAPSE is suggested as an indicator of transplant-free survival in patients with systemic light-chain amyloidosis. AAPSE provided significant incremental value to established staging models.

Prediction of fluoroscopic angulations for transcatheter aortic valve implantation by CT angiography: influence on procedural parameters.

Repeated angiograms to achieve an exactly orthogonal visualization of the aortic valve plane can substantially contribute to the total contrast amount required for transcatheter aortic valve implantation (TAVI). We investigated whether pre-procedural identification of an optimal fluoroscopic projection by cardiac computed tomography (CT) can significantly reduce the amount of a procedure-related contrast agent compared with angiographic determination of suitable angulations. Eighty consecutive patients (81 ± 5 years, 55% male) with symptomatic severe aortic valve stenosis and normal renal function who underwent cardiac CT prior to TAVI were prospectively randomized. In 40 patients, a CT-predicted suitable angulation was used for the first aortic angiogram (CT cohort); in the other 40 patients, the first aortogram was acquired at LAO 10°/cranial 10 (angiography cohort). Additional aortograms were performed if no satisfactory view of the aortic valve plane was obtained. The number of aortograms needed to achieve a satisfactory fluoroscopic projection (1.2 ± 0.6 vs. 3.2 ± 1.7; P < 0.001) and the total amount of contrast agent per TAVI procedure were significantly lower in the CT cohort (95 ± 21 vs. 125 ± 36 mL; P < 0.001). Incidence of acute kidney injury was not significantly different. There was no significant difference regarding radiation dose, time of procedure, degree of post-procedural aortic regurgitation, complications and 30-day mortality between the cohorts. Pre-procedural identification of a suitable fluoroscopic projection by cardiac CT significantly reduces a procedural contrast agent volume required for TAVI.

Echocardiographic diagnosis of acute aortic syndrome in the emergency department

An 82-year-old woman was admitted to our emergency department in hemodynamically stable condition, 12h after the beginning of severe retrosternal chest pain of 1h duration, not influenced by changes in body position, nor aggravated by breathing and no more repeated. The ECG showed a typical pattern of acute pericarditis with diffuse concave upward ST-segment elevation >1 mm. Cardiac troponin levels, 12h after chest pain, were in the normal range, excluding the diagnosis of acute coronary syndrome. Chest X-ray displayed significant mediastinal enlargement. Transthoracic echocardiography documented mild anterior pericardial effusion (10 mm) and severe aneurysmal dilatation of the ascending aorta (antero-posterior diameter of 7 cm, measured 5 cm above the aortic valve plane) with significant wall thickening and no evidence of intimal flap. In addition, both left and right ventricles showed normal morphology and systolic function; pulmonary artery systolic pressure was 28 mmHg. Transesophageal echocardiography confirmed the significant dilatation of the ascending aorta, with a typical pattern of aortic penetrating ulcer (observed 5 cm above the aortic valve plane) associated with an intramural hematoma of the anterior wall, extended from the level of the sino-tubular junction to 9 cm above the aortic valve plane (acute aortic syndrome, Svensson type II). A diagnosis of acute aortic syndrome was made and, considering the risk for acute aortic dissection or aortic rupture, the patient was quickly transferred to the nearest Cardiac Surgery Center. Computed tomography confirmed the echocardiographic findings and the patient underwent replacement of the ascending aorta with a tubular prosthesis. The present case underlines the great utility of portable echocardiography in the emergency department, for the clinical evaluation of patients with different patterns of chest pain and, particularly, in the differential diagnosis of acute aortic syndromes.

Definition of the aortic valve plane by means of a novel dedicated software program: Proof of concept and validation with multi slice computed tomography

Background: Proper selection of the C-arm angulation during transcatheter aortic valve implantation ( TAVI ) is essential. Currently m ulti slice computed tomography (MSCT) is increasingly used to determine the C-arm angulation and is considered the gold standard. Yet, MSCT is not available in the catheterization laboratory and requires expertise. We sought to evaluate the accuracy of a novel software providing the optimal angiographic projection ( i.e. three cusps on one line, equally in size and posterior, right and left cusp sequence- optimal angiographic projection [ OAP ] ) based on two contrast angiograms. Methods: Software was validated by comparing the difference in OAP between MSCT (reference) and software (CAAS A-Valve) in 67 patients and by q ualitative comparison of the aortograms performed in accordance to MSCT and CAAS A-Valve defined OAP in 20 patients by 2 blinded assessors. Results: The median (IQR) difference in the OAP between MSCT and software was 12.4 (7.5-20.1) and 18.9 (10.8-28.5) degrees. For the qualitative comparison, an overall score ≥ 2 (acceptable-perfect) of 90% was reached by both observers for OAP derived by MSCT. It was 85 % and 90% (observer 1 and 2) for OAP derived from the software and was 90% after consensus. The interobserver variability (mean difference and SD ) for assessment of OAP curve and OAP itself was 1.6 ( SD = 5.8, p = .23) and 9.5 ( SD = 18.4) degrees ( p = .03) respectively . Conclusions: The CAAS A-Valve software adequately defines the OAP and is clinically useful in patients who do not have a MSCT prior to TAVI.

Abstract 17388: Cardiac MRI Derived Forward Stroke Energy is a Better Index of Left Ventricular Pump Function over Ejection Fraction in Mitral Regurgitation

Introduction: Mitral regurgitation (MR) into the low impedance left atrium (LA) enables a pop off valve effect and enables a false low end-diastolic volume and increased ejection fraction (EF). EF in these patients seems falsely high even though their ventricular contraction seems impaired, thus better indices that represent ventricular contraction are required in this lesion. Hypothesis: In this study we sought to investigate if forward stroke energy (FSE), which represents the forward kinetic energy of the blood through the aortic valve is a better indicator of ventricular contraction than EF. Methods: Phase-contrast MRI was performed in patients with MR (n=63; Mild MR =23; Moderate-severe MR=40), at the aortic and mitral valve planes, to compute the transvalvular through-plane flow. EF was measured as ((end-diastolic volume- end systolic volume)/end-diastolic volume), and FSE as (forward aortic stroke volume X mean arterial pressure). LV contractility was computed as the dynamic myocardial wall thickening over the cardiac cycle. Results: Regional peak wall thickening was significantly reduced in the moderate-severe MR groups - equatorial sector (5.9±0.6mm vs. 4.3±0.4mm, p=0.02) and apical sector (6.4±0.5mm vs. 4.5±0.3mm, p=0.003), indicating LV dysfunction with higher MR severity. EF did not capture this difference in LV contraction between the groups (50.1±3.7% vs. 48.3±3.2%, p=0.72). However, FSE demonstrated a significant difference between the two groups and a significant negative correlation (6527±483 mmHg.mL vs. 4895±282 mmHg.mL, p=0.002, r(MRfraction)=-0.42, p=0.0007). Conclusions: Forward stroke energy may better capture reduced myocardial contractility in the setting of MR, than EF - the current clinical gold standard.

Method to measure the 3D angular orientation of the aortic valve plane from a single image of a valvuloplasty balloon: Findings of a large animal proof of concept experiment

During transcatheter aortic valve replacement procedures, alignment of the interventional x-ray beam with the aortic valve plane is required to guide valve placement. The purpose of this work was to develop methods to measure x-ray beam angles which are aligned with the aortic valve plane from a single x-ray image of a valvuloplasty balloon inflated across the left ventricular outflow tract (LVOT). A custom valvuloplasty balloon and image analytics were developed. In-vivo pig experiments demonstrated that the angular orientation of the LVOT can be measured with precision less than 3°, including the influence of cardiac motion during rapid pacing. Using these methods, the angular orientation of the LVOT of a large mammal can be measured precisely and the continuous range of x-ray projection angles which are aligned with the aortic valve plane can be calculated.

A comparative analysis of ECG-gated steady state free precession magnetic resonance imaging versus transthoracic echocardiography for evaluation of aortic root dimensions.

Accurate and reproducible measurement of aortic root dimensions is essential to inform clinical decision making. Transthoracic echocardiography (TTE) is the first line test for assessment of the aortic root but has potential limitations due to its limited field of view and restricted acoustic windows. Cardiac magnetic resonance imaging (MRI) is considered the "gold standard" technique for assessment of cardiac morphology and recently MRI reference ranges for aortic root dimensions have been published. The purpose of this study was to retrospectively compare aortic root measurements obtained from TTE with those derived from cardiac MRI. Sixty-eight patients (40 males, 28 females) who had undergone both cardiac MRI and TTE imaging within a 4-month interval (mean 62 days) were included. Steady-state-free precession MRI cine imaging was performed with an acquisition plane perpendicular to the aortic root and through the true cross sectional aortic valve plane. A cusp-commissure dimension from inside wall to inside wall in end-diastole was recorded and compared with standardized TTE derived Valsalva sinus measurements. Pearson correlation coefficients and a paired t-test were used for statistical analysis. Mean aortic root dimension by TTE was 3.2±0.5 cm and MRI was 3.4±0.4 cm with a Pearson correlation coefficient of >0.7. Mean difference between TTE and MRI was 0.2±0.3 (P<0.001) with MRI producing a consistently higher measure. In four patients with a dilated aortic root by MRI the TTE measurement was within the normal reference range. In patients with a dilated aortic root (n=19) the mean difference was 0.2±0.4 cm (P<0.05) with MRI consistently producing the larger measure. In patients with a non-dilated aortic root t (n=49) the mean difference was 0.2±0.3 cm (P<0.05) with MRI consistently producing the larger measure. There is a high level of correlation between TTE and MRI derived aortic root measurements at the Valsalva sinus level. MRI consistently measures the aortic root dimension higher than TTE which may under diagnose patients with a mildly dilated aortic root. Further investigation is required to properly integrate MRI into imaging assessment algorithms.

SU‐C‐18C‐02: Specifcation of X‐Ray Projection Angles Which Are Aligned with the Aortic Valve Plane From a Planar Image of a Valvuloplasty Balloon Inflated Across the Aortic Valve

Purpose:Transcatheter aortic valve replacement (TAVR) procedures provide a method to implant a prosthetic aortic valve via a minimallyinvasive, catheter‐based procedure. TAVR procedures require use of interventional fluoroscopy c‐arm projection angles which are aligned with the aortic valve plane to minimize prosthetic valve positioning error due to x‐ray imaging parallax. The purpose of this work is to calculate the continuous range of interventional fluoroscopy c‐arm projection angles which are aligned with the aortic valve plane from a single planar image of a valvuloplasty balloon inflated across the aortic valve.Methods:Computational methods to measure the 3D angular orientation of the aortic valve were developed. Required inputs include a planar x‐ray image of a known valvuloplasty balloon inflated across the aortic valve and specifications of x‐ray imaging geometry from the DICOM header of the image. A‐priori knowledge of the species‐specific typical range of aortic orientation is required to specify the sign of the angle of the long axis of the balloon with respect to the x‐ray beam. The methods were validated ex‐vivo and in a live pig.Results:Ex‐vivo experiments demonstrated that the angular orientation of a stationary inflated valvuloplasty balloon can be measured with precision less than 1 degree. In‐vivo pig experiments demonstrated that cardiac motion contributed to measurement variability, with precision less than 3 degrees. Error in specification of x‐ray geometry directly influences measurement accuracy.Conclusion:This work demonstrates that the 3D angular orientation of the aortic valve can be calculated precisely from a planar image of a valvuloplasty balloon inflated across the aortic valve and known x‐ray geometry. This method could be used to determine appropriate c‐arm angular projections during TAVR procedures to minimize x‐ray imaging parallax and thereby minimize prosthetic valve positioning errors.

ACR Appropriateness Criteria Imaging for Transcatheter Aortic Valve Replacement

Although aortic valve replacement is the definitive therapy for severe aortic stenosis, almost half of patients with severe aortic stenosis are unable to undergo conventional aortic valve replacement because of advanced age, comorbidities, or prohibitive surgical risk. Treatment options have been recently expanded with the introduction of catheter-based implantation of a bioprosthetic aortic valve, referred to as transcatheter aortic valve replacement. Because this procedure is characterized by lack of exposure of the operative field, image guidance plays a critical role in preprocedural planning. This guideline document evaluates several preintervention imaging examinations that focus on both imaging at the aortic valve plane and planning in the supravalvular aorta and iliofemoral system. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every 2 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances in which evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.