Integrative echocardiographic assessment of post-operative obstruction severity and restenosis after balloon valvuloplasty in 81 dogs with pulmonary stenosis.

INTRODUCTION/OBJECTIVES: Pulmonary stenosis (PS) is a congenital defect in the dog that is managed with balloon valvuloplasty (BV). Obstruction severity is routinely assessed using transthoracic echocardiography. The objectives of this study were to describe the short-term changes and long-term restenosis by retrospectively evaluating flow-dependent and flow-independent echocardiographic variables for dogs with PS after BV. ANIMALS, MATERIALS, AND METHODS: Medical records and stored echocardiographic images were reviewed from dogs that received BV for PS. The following echocardiographic variables were measured or calculated: maximum systolic ejection velocity (VmaxPV) and velocity-derived maximal pressure gradient (PV maxPG) across the pulmonary valve; ratio of aortic to pulmonary velocity time integral (VTIAV/VTIPV); ratio of aortic to pulmonary maximal velocity. RESULTS: Eighty-one dogs with PS that had a BV were included. Each of these dogs had pulmonary obstruction severity assessed in at least three timepoints. Forty-nine dogs had at least one additional examination performed, the last of which occurred a median of 504 days after the BV. Echocardiographic variables at the first follow-up had increased by a clinically relevant quantity in 20-34% of the dogs when comparing to the immediate post-BV examination. The last follow-up examination identified valve restenosis in 18-38% of the dogs in this study. Valve type and pre-BV obstruction severity did not have a significant effect (P > 0.1). CONCLUSIONS: For the assessment of BV efficacy, the immediate post-BV echocardiogram may not be as useful as the first follow-up examination several months later. Pulmonary restenosis after BV may be more prevalent than previously reported.

Longitudinal Assessment of the Doppler-Estimated Maximum Gradient in Patients With Congenital Valvar Aortic Stenosis Pre- and Post-Balloon Valvuloplasty.

BACKGROUND: Aortic stenosis has been reported to manifest a slow rate of progression in mild disease, with a greater likelihood of progression in patients with moderate-severe disease. The natural history of the Doppler-estimated maximum gradient (DEMG) in patients after balloon aortic valvuloplasty (BAVP) has not previously been studied on a large scale. METHODS AND RESULTS: A retrospective review was performed of 360 patients from 1984 to 2012 with aortic stenosis, providing a total of 2059 echocardiograms both before and after BAVP. Patients were excluded if they had an intervention within the first 30 days of life. The relationships between the aortic stenosis DEMG and several predictors (age at initial study, body surface area, valve morphology, and initial DEMG) were explored using linear mixed effect models. Patients with a unicommissural aortic valve had a significantly higher rate of progression compared with those with a bicommissural aortic valve (0.81 and 0.45 mm Hg/year; P<0.001). The median rate of progression in the post-BAVP group was significantly lower than the median pre-BAVP rate of progression (n=34; pre-BAVP 3.97 [1.69-8.7] mm Hg/year; post-BAVP 0.40 [-1.80 to 3.88] mm Hg/year; P<0.008). When adjusted for body surface area, there was no significant increase in the DEMG (-0.03 mm Hg/m2 per year; P<0.001). CONCLUSIONS: There is a statistically significant increase in the DEMG over time in patients with aortic stenosis. After balloon dilation, the DEMG rate of change is reduced compared with that pre-dilation. Given the effect of body surface area on DEMG progression, more frequent observation should be made during periods of rapid somatic growth.

Cardiac magnetic resonance versus transthoracic echocardiography for the assessment and quantification of aortic regurgitation in patients undergoing transcatheter aortic valve implantation.

BACKGROUND: The transthoracic echocardiographic (TTE) evaluation of the severity of residual aortic regurgitation (AR) following transcatheter aortic valve implantation (TAVI) has been controversial and lacks validation. OBJECTIVES: This study sought to compare TTE and cardiac magnetic resonance (CMR) for assessment of AR in patients undergoing TAVI with a balloon-expandable valve. METHODS: TTE and CMR exams were performed pre-TAVI in 50 patients and were repeated postprocedure in 42 patients. All imaging data were analysed in centralised core laboratories. RESULTS: The severity of native AR as determined by multiparametric TTE approach correlated well with the regurgitant volume and regurgitant fraction determined by CMR prior to TAVI (Rs=0.79 and 0.80, respectively; p<0.001 for both). However, after TAVI, the correlation between the prosthetic AR severity assessed by TTE and regurgitant volume and fraction measured by CMR was only modest (Rs=0.59 and 0.59, respectively; p<0.001 for both), with an underestimation of AR severity by TTE in 61.9% of patients (1 grade in 59.5%). The TTE jet diameter in parasternal view and the multiparametric approach (Rs=0.62 and 0.59, respectively; both with p<0.001) showed the best correlation with CMR regurgitant fraction post-TAVI. The circumferential extent of prosthetic paravalvular regurgitation showed a poor correlation with CMR regurgitant volume and fraction (Rs=0.32, p=0.084; Rs=0.36, p=0.054, respectively). CONCLUSIONS: The severity of AR following TAVI with a balloon-expandable valve was underestimated by echocardiography as compared with CMR. The jet diameter, but not the circumferential extent of the leaks, and the multiparametric echocardiography integrative approach best correlated with CMR findings. These results provide important insight into the evaluation of AR severity post-TAVI.

Assessment of right ventricular strain and strain rate in patients with severe mitral stenosis before and after balloon mitral valvuloplasty.

OBJECTIVE: Right ventricular (RV) dysfunction in isolated severe mitral stenosis (MS) patients have prognostic significance. Study aim was to assess RV function in these subjects by strain and strain rate analysis, pre and post-balloon mitral valvuloplasty (BMV). METHODS: Twenty five patients with isolated severe MS in sinus rhythm were assessed for RV function by two dimensional (2D) longitudinal strain & strain rate imaging before and after BMV and compared with that from twelve healthy age matched controls. RESULTS: Patients with severe MS had significantly lower global RV systolic strain; segmental strain at basal, mid, apical septum and basal RV free wall; but similar strain at mid and apical RV free wall as compared to controls. The systolic strain rate was significantly lower only at mid septum. In addition, they had higher estimated pulmonary artery systolic pressure and RV myocardial performance index; lower tricuspid annular plane systolic excursion (TAPSE), peak systolic velocity at lateral tricuspid annulus, isovolumic acceleration and fractional area change (FAC). Global RV systolic strain as well as, segmental strain at basal, mid and apical septum showed a statistically significant rise after BMV. TAPSE and FAC also increased significantly post BMV. CONCLUSIONS: RV systolic function is impaired in patients with severe MS and can be assessed by global and segmental RV strain before the appearance of clinical signs of systemic venous congestion. Impaired global and segmental RV strain values in these patients are primarily due to increased after load and improve after BMV with reduction in RV afterload.

The accuracy of three-dimensional echocardiography with multiplanar reformatting in the assessment of the aortic valve annulus prior to percutaneous balloon aortic valvuloplasty in congenital heart disease.

OBJECTIVE: To review the use of three-dimensional echocardiography (3DE) with multiplanar reformatting (MPR) in children with congenital aortic stensosis undergoing percutaneous balloon aortic valvuloplasty to assess its accuracy in measuring the aortic valve annulus and any influence it may have on balloon sizing. METHODS: All percutaneous aortic balloon valvuloplasties performed from 01/01/2009 to 01/09/2011 were included in the study. All imaging performed for the procedure to determine the size of the aortic valve annulus and aid in balloon sizing was reviewed. The maximum diameter of the aortic valve annulus using two-dimensional echocardiography (2DE), 3DE with MPR, and angiography was recorded. The balloon size used in the procedure was recorded and the balloon to annulus ratio was calculated. RESULTS: A total of 27 procedures were included in the study. Age varied from 1 day to 156 months (mean age, 53 months) and weight from 2.8-58 kg (mean weight, 18.6 kg). Fourteen patients had 3DE with MPR available for analysis. The 3DE with MPR measurement (13.36 ± 5.4 mm) was not different from angiography (13.54 ± 6.4 mm; P=.803).The 2DE measurement was significantly different from angiography (11.72 ± 5 mm; P<.005). The balloon to annulus ratio based on angiographic measurements did not differ significantly between the patients with 3DE MPR and those without (0.94 ± 0.095 vs 0.91 ± 0.1; P=.468). CONCLUSION: 3DE with MPR allows a more accurate assessment of the aortic valve annulus compared to 2DE, which may reduce the tendency to undersize balloon choice. 3DE with MPR did not significantly affect our balloon choice, which was largely based on angiographic measurements.