Quantitative assessment of paravalvular regurgitation following transcatheter aortic valve replacement.

BACKGROUND: Paravalvular aortic regurgitation (PAR) following transcatheter aortic valve implantation (TAVI) is well acknowledged. Despite improvements, echocardiographic measurement of PAR largely remains qualitative. Cardiovascular magnetic resonance (CMR) directly quantifies AR with accuracy and reproducibility. We compared CMR and transthoracic echocardiography (TTE) analysis of pre-operative and post-operative aortic regurgitation in patients undergoing both TAVI and surgical aortic valve replacement (AVR). METHODS: Eighty-seven patients with severe aortic stenosis undergoing TAVI (56 patients) or AVR were recruited. CMR (1.5 T) and transthoracic echocardiography (TTE) were carried out pre-operatively and a median of 6 days post-operatively. The CMR protocol included regurgitant aortic flows using through-plane phase-contrast velocity. None/trivial, mild, moderate and severe AR by CMR was defined as ≤8%, 9-20%, 21-39%, >40% regurgitant fractions respectively. RESULTS: Pre- and post-operative left ventricular ejection fraction (LVEF) was similar. Post-procedure aortic regurgitant fraction using CMR was higher in the TAVI group (TAVI 16 ± 13% vs. AVR 4 ± 4%, p < 0.01). Comparing CMR to TTE, 27 of 56 (48%) TAVI patients had PAR which was at least one grade more severe on CMR than TTE (Z = -4.56, p <0.001). Sensitivity analysis confirmed the difference in PAR grade between TTE and CMR in the TAVI group (Z = -4.49, p < 0.001). CONCLUSION: When compared to CMR based quantitative analysis, TTE underestimated the degree of paravalvular aortic regurgitation. This underestimation may in part explain the findings of increased mortality associated with mild or greater AR by TTE in the PARTNER trial. Paravalvular aortic regurgitation post TAVI assessed as mild by TTE may in fact be more severe.

Early effects of transcatheter aortic valve implantation and aortic valve replacement on myocardial function and aortic valve hemodynamics: insights from cardiovascular magnetic resonance imaging.

OBJECTIVES: There remains a paucity of mechanistic data on the effect of transcatheter aortic valve implantation (TAVI) on early left and right ventricular function and quantitative aortic valve regurgitation. We sought to assess and compare the early effects on myocardial function and aortic valve hemodynamics of TAVI and aortic valve replacement (AVR) using serial cardiovascular magnetic resonance (CMR) imaging and echocardiography. METHODS: A prospective comparison study of 47 patients with severe aortic stenosis undergoing either TAVI (n = 26) or high-risk AVR (n = 21). CMR (for left ventricle/right ventricle function, left ventricular mass, left atrial volume, and aortic regurgitation) was carried out before the procedure and early postprocedure (<14 days). RESULTS: Groups were similar with respect to Society of Thoracic Surgeons score (TAVI, 7.7 vs AVR, 5.9; P = .11). Preoperative left ventricular (TAVI, 69% ± 13% vs AVR, 73% ± 10%; P = .10) and right ventricular (TAVI, 61% ± 11% vs AVR, 59% ± 8%; P = .5) ejection fractions were similar. Postoperative left ventricular ejection fraction was preserved in both groups. In contrast, decline in right ventricular ejection fraction was more significant in the TAVI group (61%-54% vs 59%-58%; P = .01). Postprocedure aortic regurgitant fraction was significantly greater in the TAVI group (16% vs 4%; P = .001), as was left atrial size (110 vs 84 mL; P = .02). Further analysis revealed a significant relationship between the increased aortic regurgitant fraction and greater left atrial size (P = .006), and a trend toward association between the decline in right ventricle dysfunction and increased postprocedure aortic regurgitation (P = .08). CONCLUSIONS: There was no significant difference in early left ventricular systolic function between techniques. Whereas right ventricle systolic function was preserved in the AVR group, it was significantly impaired early after TAVI, possibly reflecting a clinically important pathophysiologic consequence of paravalvular aortic regurgitation.

Speckle-tracking strain of the left atrium: a transoesophageal echocardiographic validation study.

AIMS: The aims of this study were (1) to evaluate the relationship between novel two-dimensional transthoracic indices of left atrial (LA) mechanical function (speckle-tracking- and tissue Doppler-derived parameters), conventional indices (A-wave peak velocity and velocity-time integral, and A' velocity), and transoesophageal echocardiographic parameters (LA appendage emptying velocity and spontaneous echocardiographic contrast); and (2) to assess to clinical feasibility of these novel transthoracic echocardiographic indices. METHODS AND RESULTS: Transthoracic echocardiography was performed immediately prior to or following clinically indicated transoesophageal echocardiography in 100 individuals. Longitudinal reservoir LA strain, and reservoir, conduit, and atrial contractile strain rate were measured by both speckle-tracking and tissue Doppler approaches. Inter- and intra-observer variability in 20 randomly selected cases was evaluated by the Bland-Altman technique. The time required per analysis for these novel transthoracic echocardiographic indices was recorded. In relation to LA appendage emptying velocity, the respective absolute r-values for speckle-tracking reservoir strain, and reservoir, conduit, and atrial contractile strain rate were 0.53 (P < 0.001), 0.40 (P < 0.001), 0.21 (P = 0.05), and 0.61 (P < 0.001). The absolute r-values for tissue Doppler reservoir strain, and reservoir, conduit, and atrial contractile strain rate were 0.57 (P < 0.005), 0.53 (P < 0.001), 0.022 (P = 0.8), and 0.46 (P < 0.001), respectively. In contrast, the r-values for A-wave peak velocity and velocity-time integral, and A' velocity were 0.20 (P = 0.01), 0.26 (P = 0.05), and 0.35 (P = 0.007), respectively. Speckle-tracking-derived parameters achieved the greatest area-under-the-receiver-operating characteristic curve in the identification of moderate-severe LA spontaneous echocardigraphic contrast and were more rapidly measured (P < 0.001), while exhibiting similar reproducibility to tissue Doppler-derived measures. CONCLUSION: Assessment of LA mechanical function using speckle-tracking echocardiography is a valid approach compared with transoesophageal echocardiography, and is clinically feasible.

A rare case of penetrating atherosclerotic ulcer of the aorta.

We are reporting a case of 66 year-old man who presented to a regional hospital with sudden onset of inter-scapular pain, radiating to anterior chest. Initial assessment was unremarkable except for high blood pressure and computed tomography (CT) of chest showing an intramural haematoma in the thoracic descending aorta. He was transferred to our institution for the medical management of his blood pressure and intramural haematoma of the aorta. A transoesophageal echocardiography confirmed the diagnosis but in addition demonstrated a penetrating atherosclerotic ulcer (PAU). Subsequently CT aortogram revealed a slow leak from the PAU. Endovascular repair with stent-grafting was urgently performed. He improved clinically and remained well on discharge. This case demonstrated that PAU, although rare and often under-recognised, is potentially life-threatening and should be considered in the evaluation of chest pain. Multi-modality imaging techniques can aid the diagnosis and guide appropriate and timely management.

Nonvolumetric echocardiographic indices of right ventricular systolic function: validation with cardiovascular magnetic resonance and relationship with functional capacity.

PURPOSE: Right ventricular (RV) systolic function as measured by right ventricular ejection fraction (RVEF) has long been recognized as an important predictor of outcome in heart failure patients. The echocardiographic measurement of RV volumes and RVEF is challenging, however, owing to the unique geometry of the right ventricle. Several nonvolumetric echocardiographic indices of RV function have demonstrated prognostic value in heart failure. Comparison studies of these techniques with each other using RVEF as a benchmark are limited, however. Furthermore, the contribution of these various elements of RV function to patient functional status is uncertain. We therefore aimed to: (1) Determine which nonvolumetric echocardiographic index correlates best with RVEF as determined by cardiac magnetic resonance (CMR) imaging (the accepted gold standard measure of RV systolic function) and (2) Ascertain which echocardiographic index best predicts functional capacity. METHODS: Eighty-three subjects (66 with systolic heart failure and 17 healthy controls) underwent CMR, 2D echocardiography, and cardiopulmonary exercise testing for comparison of echocardiographic indices of RV function with CMR RVEF, 6-minute walk distance and VO(2 PEAK). RESULTS: Speckle tracking strain RV strain exhibited the closest association with CMR RV ejection fraction. Indices of RV function demonstrated weak correlation with 6-minute walk distance, but basal RV strain rate by tissue velocity imaging had good correlation with VO(2 PEAK). CONCLUSION: Strain by speckle tracking echocardiography and strain rate by tissue velocity imaging may offer complementary information in the evaluation of RV contractility and its functional effects.