Impact of Interventricular Interaction on Ventricular Function: Insights From Right Ventricular Pressure-Volume Analysis.

BACKGROUND: Interventricular interactions may be responsible for the decline in ventricular performance observed in various disease states that primarily affect the contralateral ventricle. OBJECTIVES: This study sought to quantify the impact of such interactions on right ventricular (RV) size and function using clinically stable individuals with left ventricular assist devices (LVADs) as a model for assessing RV hemodynamics while LV loading conditions were acutely manipulated by changing device speed during hemodynamic optimization studies (ie, ramp tests). METHODS: The investigators recorded RV pressure-volume loops with a conductance catheter at various speeds during ramp tests in 20 clinically stable HeartMate3 recipients. RESULTS: With faster LVAD speeds and greater LV unloading, indexed RV end-diastolic volume increased (72.28 ± 15.07 mL at low speed vs 75.95 ± 16.90 at high speed; P = 0.04) whereas indexed end-systolic volumes remained neutral. This resulted in larger RV stroke volumes and shallower end-diastolic pressure-volume relationships. Concurrently, RV end-systolic pressure decreased (31.58 ± 9.75 mL at low speed vs 29.58 ± 9.41 mL at high speed; P = 0.02), but contractility, as measured by end-systolic elastance, did not change significantly. The reduction in RV end-systolic pressure was associated with a reduction in effective arterial elastance from 0.65 ± 0.43 mm Hg/mL at low speed to 0.54 ± 0.33 mm Hg/mL at high speed (P = 0.02). CONCLUSIONS: Interventricular interactions resulted in improved RV compliance, diminished afterload, and did not reduce RV contractility. These data challenge the prevailing view that interventricular interactions compromise RV function, which has important implications for the understanding of RV-LV interactions in various disease states, including post-LVAD RV dysfunction.

Right Heart Morphology of Candidate Patients for Transcatheter Tricuspid Valve Interventions.

PURPOSE: This study quantitatively evaluated the phasic right heart morphology of candidate patients for a transcatheter tricuspid valve intervention (N=32) and of subjects with trace to no tricuspid regurgitation (N = 14). METHODS: Cardiac computed tomography angiography (CCTA) and transthoracic/transesophageal echocardiography (TTE/TEE) images were analyzed using dedicated research and clinical software. Using CCTA, the phasic right atrial and ventricular volumes, annulus dimensions, annulus-to-right coronary artery (RCA) distances, circumferential topography of the annular tissue shelf, vena cava dimensions (inferior and superior), vena cava positions, axis angles, and annular excursions were quantified. Using TTE/TEE, leaflet geometry, regurgitation, hemodynamics, and heart function were quantified. Measurements within and between groups were quantitatively compared with regression analyses to explore relationships between right heart features. RESULTS: The phasic position and orientation of the vena cava and the circumferential topography of the annular tissue shelf were quantitatively presented for the first time. The candidate patient group exhibited greater chamber dimensions, enlarged vena cava, distended vena cava positions, positional shallowing of the annular tissue shelf, geometric annular distortion, leaflet distention, moderate or greater regurgitation, and impaired ventricular function. Atrial volume correlated strongly with directional vena cava positions as well as with annular dimensions. Annulus-to-RCA distances and annular excursions were comparable between groups. CONCLUSIONS: This study provides new and further insight to the right heart morphology and functional characteristics of candidate patients for a transcatheter tricuspid valve intervention. These data provide a platform from which these patients can continue to be better understood for further improving transcatheter system design and use.

Suprasternal Versus Transfemoral Access for Transcatheter Aortic Valve Replacement: Insights From a Propensity Score Matched Analysis.

Background Suprasternal access is an alternative access strategy for transcatheter aortic valve replacement (TAVR) where the innominate artery is cannulated from an incision above the sternal notch. To date, suprasternal access has never been compared with transfemoral TAVR. Thus, we sought to assess safety, feasibility, and early clinical outcomes between suprasternal and transfemoral access for patients undergoing TAVR. Methods and Results We evaluated patients from 2 institutional prospective, observational registries containing 1348 patients. Patients were selected in a 2:1 ratio (transfemoral:suprasternal) on the basis of propensity score matching. The primary outcome was in-hospital mortality, and secondary outcomes included the incidence of ischemic stroke, major bleeding, vascular injury, left bundle-branch block, and permanent pacemaker implantation at 30-day follow-up. Propensity score matching identified 89 patients undergoing suprasternal TAVR and 159 patients undergoing transfemoral TAVR suitable for analysis. There was no significant difference between suprasternal TAVR and transfemoral TAVR with respect to in-hospital mortality (1.1% versus 0.6%; odds ratio [OR], 1.80; 95% CI, 0.11-29.06; P=0.680). No patients in either cohort suffered an ischemic stroke. The incidence of major bleeding (2.2% versus 2.5%; OR, 0.89; 95% CI, 0.16-4.96; P=0.895) and vascular injury (1.1% versus 1.9%; OR, 0.59; 95% CI, 0.06-5.77; P=0.651) did not differ significantly. The frequency of left bundle-branch block (9.4% versus 15.8%; OR, 0.56; 95% CI, 0.24-1.30; P=0.177) and permanent pacemaker implantation (11.2% versus 5.9%; OR, 2.01; 95% CI, 0.75-5.45; P=0.169) were not statistically significantly different. Conclusions Suprasternal TAVR was safe and achieved promising short-term clinical outcomes when compared with transfemoral TAVR. Future studies seeking to identify the optimal alternative access site should evaluate suprasternal TAVR access alongside other substitutes for transfemoral TAVR.

Right Ventricular Pressure-Volume Analysis During Left Ventricular Assist Device Speed Optimization Studies: Insights Into Interventricular Interactions and Right Ventricular Failure.

BACKGROUND: Interventricular interaction, which refers to the impact of left ventricular (LV) function on right ventricular (RV) function and vice versa, has been implicated in the pathogenesis of RV failure in LV assist device (LVAD) recipients. We sought to understand more about interventricular interaction by quantifying changes in the RV systolic and diastolic function with varying LVAD speeds. METHODS AND RESULTS: Four patients (ages 22-69 years, 75% male, and 25% with ischemic cardiomyopathy) underwent a protocolized hemodynamic ramp test within 12 months of LVAD implantation where RV pressure-volume loops were recorded with a conductance catheter. The end-systolic PV relationship and end-diastolic PV relationship were compared using the V20 and V10 indices (volumes at which end-systolic PV relationship and end-diastolic PV relationship reach a pressure of 20 and 10 mm Hg, respectively). The ∆V20 and ∆V10 refer to the change in V20 and V10 from the minimum to maximum LVAD speeds. RV PV loops demonstrated variable changes in systolic and diastolic function with increasing LVAD speed. The end-systolic PV relationship changed in 1 patient (patient 2, ∆V20 = 23.5 mL), reflecting a decrease in systolic function with increased speed, and was unchanged in 3 patients (average ∆V20 = 7.4 mL). The end-diastolic PV relationship changed with increasing speed in 3 of 4 patients (average ∆V10 = 12.5 mL), indicating an increase in ventricular compliance, and remained unchanged in one participant (patient 1; ∆V10 = 4.0 mL). CONCLUSIONS: Interventricular interaction can improve RV compliance and impair systolic function, but the overall effect on RV performance in this pilot investigation is heterogeneous. Further research is required to understand which patient characteristics and hemodynamic parameters influence the net impact of interventricular interaction.

Practical determination of aortic valve calcium volume score on contrast-enhanced computed tomography prior to transcatheter aortic valve replacement and impact on paravalvular regurgitation: Elucidating optimal threshold cutoffs.

BACKGROUND: The threshold for the optimal computed tomography (CT) number in Hounsfield Units (HU) to quantify aortic valvular calcium on contrast-enhanced scans has not been standardized. Our aim was to find the most accurate threshold to predict paravalvular regurgitation (PVR) after transcatheter aortic valve replacement (TAVR). METHODS: 104 patients who underwent TAVR with the CoreValve prosthesis were studied retrospectively. Luminal attenuation (LA) in HU was measured at the level of the aortic annulus. Calcium volume score for the aortic valvular complex was measured using 6 threshold cutoffs (650 HU, 850 HU, LA × 1.25, LA × 1.5, LA+50, LA+100). Receiver-operating characteristic (ROC) analysis was performed to assess the predictive value for > mild PVR (n = 16). Multivariable analysis was performed to determine the accuracy to predict > mild PVR after adjustment for depth and perimeter oversizing. RESULTS: ROC analysis showed lower area under the curve (AUC) values for fixed threshold cutoffs (650 or 850 HU) compared to thresholds relative to LA. The LA+100 threshold had the highest AUC (0.81), and AUC was higher than all studied protocols, other than the LA x 1.25 and LA + 50 protocols, where the difference approached statistical significance (p = 0.05, and 0.068, respectively). Multivariable analysis showed calcium volume determined by the LAx1.25, LAx1.5, LA+50, and LA+ 100 HU protocols to independently predict PVR. CONCLUSIONS: Calcium volume scoring thresholds which are relative to LA are more predictive of PVR post-TAVR than those which use fixed cutoffs. A threshold of LA+100 HU had the highest predictive value.

Injuries to the Aorta, Aortic Annulus, and Left Ventricle During Transcatheter Aortic Valve Replacement: Management and Outcomes.

The experience with transcatheter aortic valve replacement is increasing worldwide; however, the incidence of potentially catastrophic cardiac or aortic complications has not decreased. In most cases, significant injuries to the aorta, aortic valve annulus, and left ventricle require open surgical repair. However, the transcatheter aortic valve replacement patient presents a unique challenge as many patients are at high or prohibitive surgical risk and, therefore, an open surgical procedure may not be feasible or appropriate. Consequently, prevention of these potentially catastrophic injuries is vital, and practitioners need to understand when open surgical repair is required and when alternative management strategies can be used. The goal of this article is to provide an overview of current management and prevention strategies for major complications involving the aorta, aortic valve annulus, and left ventricle.

Impact of Methodologic Differences in Three-Dimensional Echocardiographic Measurements of the Aortic Annulus Compared with Computed Tomographic Angiography Before Transcatheter Aortic Valve Replacement.

BACKGROUND: Three-dimensional (3D) echocardiographic (3DE) imaging is an alternative to multi-detector row computed tomography (MDCT) for aortic annular measurement before transcatheter aortic valve replacement (TAVR). A commonly used direct planimetry from a reconstructed short-axis view has not been compared with semiautomated 3DE methods. Typically accepted optimal cutoffs for percent prosthesis-area oversizing of the balloon-expandable SAPIEN or SAPIEN XT valve to native annular size are approximately 5% to 15%. The aim of this study was to compare semiautomated and direct planimetric 3DE methods for aortic annular sizing with a gold standard of MDCT to determine predictive value for paravalvular regurgitation (PVR) and balloon postdilatation. METHODS: In this retrospective analysis, aortic annular cross-sectional area was measured from pre-TAVR imaging using (1) MDCT (CT_Area), (2) a 3D transesophageal echocardiographic (TEE) semiautomated method (3DE_Area_SA), and (3) a 3D TEE direct planimetric method (3DE_Area_Direct). Annular area percent oversizing was calculated. PVR after TAVR was assessed from intraoperative TEE imaging. Need for balloon postdilatation was recorded. RESULTS: One hundred patients who underwent TAVR with either the SAPIEN or SAPIEN XT balloon-expandable prosthesis were analyzed. Twenty-three patients had mild or greater PVR after TAVR. CT_Area was 442 ± 79 mm2, 3DE_Area_SA was 435 ± 81 mm2, and 3DE_Area_Direct was 429 ± 82 mm2. Both 3DE_Area_SA and 3DE_Area_Direct underestimated MDCT (P < .05). All methods were highly correlative (R = 0.88-0.93, P < .0001). Percent oversizing obtained by the three methods significantly predicted mild or greater PVR and need for balloon postdilatation by receiver operating characteristic analysis, with optimal cutoffs for CT_Area (9%-10%) and 3DE_Area_SA (14%) within the recommended ranges for the studied transcatheter valves and for 3DE_Area_Direct higher than the recommended range (18%-19%). Inter- and intraobserver reproducibility were lowest for 3DE_Area_Direct. CONCLUSIONS: Caution must be used when using 3D TEE direct planimetry of the aortic annulus, as optimal percent oversizing ranges approach the level associated with root injury, and measurements are less reproducible. Therefore, semiautomated 3DE planimetry is preferred to 3DE direct planimetry for aortic annulus sizing.

Improving the accuracy of effective orifice area assessment after transcatheter aortic valve replacement: validation of left ventricular outflow tract diameter and pulsed-wave Doppler location and impact of three-dimensional measurements.

BACKGROUND: Echocardiographic calculation of effective orifice area (EOA) after transcatheter aortic valve replacement is integral to the assessment of transcatheter heart valve (THV) function. The aim of this study was to determine the most accurate method for calculating the EOA of the Edwards SAPIEN and SAPIEN XT THVs. METHODS: One hundred intraprocedural transesophageal echocardiograms were analyzed. To calculate the post-transcatheter aortic valve replacement left ventricular outflow tract (LVOT) stroke volume (SV), four diameters were measured using two-dimensional echocardiography: (1) baseline LVOT diameter (LVOTd_PRE), (2) postimplantation LVOT diameter, (3) native aortic annular diameter, and (4) THV in-stent diameter. Four corresponding areas were planimetered by three-dimensional echocardiography. Two LVOT velocity-time integrals (VTI) were measured with the pulsed-wave Doppler sample volume at (1) the proximal (apical) edge of the valve stent or (2) within the valve stent at the level of the THV cusps. LVOT velocity-time integral with the sample volume at the proximal edge of the valve stent was used with the LVOT and aortic annular measurements above, whereas in-stent VTI was paired with the in-stent THV diameter to yield eight different SVs. Right ventricular outflow tract (RVOT) SV was calculated using RVOT diameter and RVOT VTI and was used as the primary comparator. Transaortic VTI was obtained by continuous-wave Doppler, and EOA calculations using each SV measurement were compared with (1) EOA calculated using RVOTSV and (2) planimetered aortic valve area using three-dimensional echocardiography (AVAplanimetry3D). RESULTS: Post-transcatheter aortic valve replacement EOA calculated using LVOTd_PRE was not significantly different from EOA calculated using RVOTSV (1.88 ± 0.33 vs 1.86 ± 0.39 cm(2), P = .36) or from AVAplanimetry3D (1.85 ± 0.28, P = .38, n = 34). All other two-dimensional EOA calculations were statistically larger than EOA calculated using RVOTSV. All three-dimensional echocardiography-based EOA calculations were statistically different from AVAplanimetry3D. CONCLUSIONS: The most accurate EOA after implantation of a balloon-expandable THV is calculated using preimplantation LVOT diameter and VTI.

Transcatheter Valve Implantation in Failed Surgically Inserted Bioprosthesis: Review and Practical Guide to Echocardiographic Imaging in Valve-in-Valve Procedures.

An increased use of bioprosthetic heart valves has stimulated an interest in possible transcatheter options for bioprosthetic valve failure given the high operative risk. The encouraging results of transcatheter aortic valve implantation in high-risk surgical candidates with native disease have led to the development of the transcatheter valve-in-valve (VIV) procedures for failed bioprostheses. VIV procedures are unique in many ways, and there is an increased need for multimodality imaging in a team-based approach. The echocardiographic approach to VIV procedures has not previously been described. In this review, we summarize key echocardiographic requirements for optimal patient selection, procedural guidance, and immediate post-procedural assessment for VIV procedures.