A practical approach to the quantification of valvular regurgitation

Tricuspid valve dysplasia: A retrospective study of clinical features and outcome in dogs in the UK

The objective of this study was to determine the demographic, clinical and survival characteristics and to identify risk factors for mortality due to tricuspid valve dysplasia in UK dogs. Records of client-owned dogs diagnosed with tricuspid valve dysplasia at a referral centre were retrospectively reviewed. Only dogs diagnosed with tricuspid valve dysplasia based on the presence of a right-sided heart murmur identified prior to one year of age, and confirmed with Doppler echocardiography, were included. Dogs with concomitant cardiac diseases, pulmonary hypertension and/or trivial tricuspid regurgitation were excluded. Analysed data included signalment, reason for presentation, clinical signs, electrocardiographic and echocardiographic features, survival status and cause of death. Survival times and risk factors for mortality were evaluated using Kaplan-Meier curves and Cox regression. Eighteen dogs met inclusion criteria. Border collies were over-represented (p= 0.014). Dogs were most frequently referred for investigation of heart murmur. The most common arrhythmia was atrial fibrillation (n=3). Median survival time from diagnosis of tricuspid valve dysplasia was 2775 days (range 1-3696 days; 95% CI 1542.41-4007.59) and from onset of right-sided congestive heart failure was 181 days (range 1-2130 days; 95% CI 0-455.59). Syncope was the sole risk factor for cardiac death. In this population of UK dogs, tricuspid valve dysplasia was uncommon but, when severe, frequently led to right-sided congestive heart failure. Prognosis was favourable for mild and moderate tricuspid dysplasia. Survival time was reduced with right-sided congestive heart failure but varied widely. Risk of cardiac death was significantly increased if syncope had occurred.

Assessment of mitral regurgitation severity by Doppler color flow mapping of the vena contracta in dogs

BACKGROUND

Quantitative and semiquantitative methods have been proposed for the assessment of MR severity, and though all are associated with limitations. Measurement of vena contracta width (VCW) has been used in clinical practice.

OBJECTIVE

To measure the VCW in dogs with different levels of MR severity.

ANIMALS

Two hundred and seventy-nine dogs were classified according to 5 levels of MR severity.

METHODS

This was a retrospective study. EROA and regurgitant volume calculated by the PISA method, were measured and indexed to BSA. Descriptive statistics were calculated for VCW and VCW index for all categories of MR severity. Spearman's rank correlation coefficients (ρs ) were calculated to compare the results of the different methods (VCW and VCW index vs RV PISA, RV PISA index, EROA, EROA index), and between VCW and VCW index versus MR severity.

RESULTS

All Spearman's rank correlation coefficients were significant (P < .001). The median values of VCW resulted of 2.9 mm (IQR 3.4-2.5) and of 4.6 mm (IQR 5.4-4.1) in the groups previously classified as mild-to-moderate and moderate-to-severe, respectively. The median values of VCW index resulted of 4.4 mm/m(2) (IQR = 5.5-4.2) in mild-to-moderate MR and of 10.8 mm/m(2) (IQR = 12.8-9.4) in moderate-to-severe MR.

CONCLUSION AND CLINICAL IMPORTANCE

This is not a validation study against any previously validated invasive gold standard, the VCW method has proved easy to employ and it might be an additional tool in quantifying disease severity that supports, rather than replace, data coming from other techniques in daily clinical practice and research.

Proximal isovelocity surface area variability during systole in dogs with mitral valve prolapse

The proximal isovelocity surface area (PISA) principles and methodology have been described in human and veterinary medicine with special emphasis given to the ease and speed for the quantification of mitral regurgitation. Although limitations have been described in both human and veterinary medicine, in the case of veterinary medicine, clinical examples have not been well defined and in some cases have not been individually presented. The objective of this paper is to illustrate in a qualitative manner the echocardiographic existence of the dynamic behavior and variability of mitral regurgitation in dogs with mitral valve prolapse, a factor to be taken into consideration as a limitation inherent to the PISA technique.

Is the function of all cardiac valves after the arterial switch operation influenced by an associated ventricular septal defect?

A ventricular septal defect in transposition of the great arteries is frequently closely related to the cardiac valves. The valvar function after arterial switch operation of patients with transposition of the great arteries and ventricular septal defect or intact ventricular septum was compared. We analysed the function of all cardiac valves in patients who underwent the arterial switch operations pre- and post-operatively, 1 year after the procedure and on follow-up. The study included 92 patients - 64 with transposition of the great arteries/intact ventricular septum and 28 with transposition of the great arteries/ventricular septal defect. The median age at surgery was 5.5 days in transposition of the great arteries/intact ventricular septum (0-73 days) and 7.0 days in transposition of the great arteries/ventricular septal defect (4-41 days). Follow-up was 51.7 months in transposition of the great arteries/intact ventricular septum (3.3-177.3 months) and 55 months in transposition of the great arteries/ventricular septal defect (14.6-164.7 months). Neo-aortic, neo-pulmonary, and mitral valvar function did not differ. Tricuspid regurgitation was more frequent 1 year post-operatively in transposition of the great arteries/ventricular septal defect (n = 4) than in transposition of the great arteries/intact ventricular septum. The prevalence of neo-aortic regurgitation and pulmonary stenosis increased over time, especially in patients with transposition of the great arteries/intact ventricular septum. The presence of a ventricular septal defect in patients undergoing arterial switch operation for transposition of the great arteries only has a minor bearing for the development of valvar dysfunction on the longer follow-up.

Accelerated phase-contrast MR imaging: comparison of k-t BLAST with SENSE and Doppler ultrasound for velocity and flow measurements in the aorta

PURPOSE

To evaluate differences in velocity and flow measurements in the aorta between accelerated phase-contrast (PC) magnetic resonance imaging (MRI) using SENSE and k-t BLAST and in peak velocity to Doppler ultrasound.

MATERIALS AND METHODS

Two-dimensional PC-MRI perpendicular to the ascending and descending aorta was performed in 11 volunteers using SENSE (R = 2) and k-t BLAST (2-, 4-, 6-, and 8-fold). Peak velocity, mean velocity, and stroke volume of the accelerated PC-MRI experiments were correlated. Peak velocities were compared to Doppler ultrasound.

RESULTS

All acceleration techniques showed significant correlations for peak velocity with Doppler ultrasound. However, k-t BLAST 6 and 8 showed a significant underestimation. Strong correlations between SENSE and k-t BLAST were found for all three parameters. Significant differences in peak velocity were found between SENSE and all k-t BLAST experiments, but not for 2-fold k-t BLAST in the ascending aorta, and 2- and 4-fold k-t BLAST in the descending aorta. For mean velocity no significant differences were found. Stroke volume showed significant differences for all k-t BLAST experiments in the ascending and for 6- and 8-fold k-t BLAST in the descending aorta.

CONCLUSION

Peak velocity of accelerated PC-MRI correlated with CW Doppler measurements, but high k-t BLAST acceleration factors lead to a significant underestimation. SENSE with R = 2 and 2-fold k-t BLAST are most highly correlated in phase-contrast flow measurements.