The 25th American Society of Echocardiography in Portland was a 4 day event which showcased some of the most prominent names in echocardiography. Whilst speakers were primarily US based, there were international speakers including our local Bonita Anderson. The conference attracted a mixed of clinicians as well as sonographers from all over the world. Here are the highlights:
Chamber Quantification – the Devil’s in the details (LA, RV, LV mass and function, Aortic and vascular dimension )
The overall focus was on how to perform quantitative measurements of various chambers of the heart using 2D and 3D. The recurring theme was that 3D echo was probably a reliable method in assessing chamber sizes especially the right ventricle. The rationale for measuring LA dimension using 3D was highlighted given that LA is a “cleaner” chamber than the LV. Increase LA volume is a common feature of diastolic dysfunction, but in itself is associated with increased adverse outcomes. Currently, most echo machines lack LA software package. Therefore, points in the LA, namely septal, lateral and apex need to be identified in order to facilitate spectral tracing. Contrast can be used in the setting of poor quality image to delineate the endocardial borders. Remember – a poor 2D equals a poor 3D. LA assessment should also be indexed to BSA (0.0001 x 71.84 x height x weight)
We all know that the RV is sometimes considered the forgotten chamber. It’s a more complex chamber due to its shape, irregular endocardial surface and the myocardial fibres are arranged differently compared to the LV. It is also incompletely visualized in any single 2D view. Hence the need for multiple views. The ASE guidelines for the assessment of RV can be found here.
The RV systolic function can be assessed using TAPSE (1.6-3cm), tissue Doppler (<0.55), fractional area change (>35%) and the RIMP(Right Index Myocardial Performance<0.4). The RV wall thickness can be measured easily in the subcostal zoom view (<5mm). Other RV measurements include the PLAX and PSAX RVOTd of <33mm and <27mm respectively. Measurement of RVEF is not recommended.
One of the speakers spoke about routinely measuring LV mass given than the increase in LV mass is associated with increased stroke risk and heart failure. This measurement is useful in patients with hypertension, HOCM and athlete screening. 3D echo results are comparable to those values obtained with cardiac MRI. Again, the ASE has produced guidelines for assessing LV mass. The ways to measure LV mass include linear measurement with M-mode, PSAX in papillary muscle view (epicardial/ endocardial border), PLAX (length from apex to mitral annulus) and of course, 3D!
Most of us are familiar with methods of measuring LV function. The 15 minute session focussed on some simple tips to improve our accuracy when using the Simpsons method. Tricks include reducing depth of field, narrow the sector, perform manual tracing and close the trace at the level of the mitral valve. Common pitfalls include apical foreshortening which will overestimate EF.
The symposia on Echo in pregnancy kicked off with a review of haemodynamic changes which occur in pregnancy. There is an increasing incidence of adult congenital heart disease who fall pregnant. A couple of cases were presented and the discussion also included birth control in high risk patients, given that these patients have a higher mortality than in the usual population. RV failure was the most common cause of mortality in this patient group. Interestingly, it is not known what constitutes as normal RV function in the pregnant patient.
Valvular heart disease with stenotic lesions or prosthetic valves, were more likely to manifest during pregnancy due to the increase in transvalvular gradient from increased cardiac output. Regurgitant lesions tended not to get worse with pregnancy due to the reduction in regurgitant volume from a reduction in systemic vascular resistance.<Concurrent sessions – Echo and the atria, Truncus arteriosus, Advanced skills in assessing diastole, Mitral valve procedures>
Peripartum cardiomyopathy can be defined as cardiac failure which can occur in the last month of pregnancy or within 5 months after delivery. The echo would show an LV EF < 45%, FS < 30% and an absence of other causes of heart failure. Risk factors include twin pregnancy, high parity, extremes of reproductive age, hypertension and pre-eclampsia. PPCM is associated with 50% mortality. About 41% of patients will recover within 6 months.
<Concurrent sessions –Extreme Echo: A sonic adventure in advanced ultrasound physics, Aortic coarctation and interrupted aortic arch, Percutaneous interventions for mitral valve pathology, Pericardial Disease>
Mechanical circulatory assist therapy for heart failure session went through the current status of VADs in the USA. The INTERMACS is the US based VADS registry. Approximately 15,000 patients have had VADS implanted over the past number of years. 40% of VADS implanted in the USA are as destination therapy. This is currently not a funded treatment option in Australia. Echocardiography is used prior to VAD placement to ensure that there is no thrombus in the left atrial appendage or apex. The other utility is to assess the right heart function, given that one of the complications post VAD is right heart failure, TR, PFO, AR, MS. TAPSE, TV annular velocity, RV FAC, Tei and RV sphericity index were all used to assess the RV. If there is moderate tricuspid regurgitation, the valve is replaced at the time of VAD placement. One of the speakers who was probably the few anaesthetist/ anesthesiologist at the conference, presented a video on how an LVAD was implanted into a live patient. Here’s a different one if you haven’t seen this procedure before…
More to come on Day 2…Tags: echocardiography conference