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Archive for the ‘cardiac MRI’ Category

Area: Height Ratio in Patients With Proximal Ascending Aortic Dilation and Trileaflet Aortic Valve

Masri et al report an observational longitudinal study of patients with proximal dilation of the ascending aorta and trileaflet aortic valves. The authors report the relationship between ascending aortic area to height ration (as assessed by CT or MRI) and clinical outcome.

Abstract

BACKGROUND:

In patients with a dilated proximal ascending aorta
and trileaflet aortic valve, we aimed to assess (1) factors independently
associated with increased long-term mortality and (2) the incremental
prognostic utility of indexing aortic root to patient height.

METHODS:

We studied consecutive patients with a dilated aortic root (≥4
cm) that underwent echocardiography and gated contrast-enhanced thoracic
aortic computed tomography or magnetic resonance angiography between
2003 and 2007. A ratio of aortic root area over height was calculated
(cm2/m) on tomography, and a cutoff of 10 cm2/m was chosen as abnormal,
on the basis of previous reports. All-cause death was recorded.

RESULTS:

The cohort comprised 771 patients (63 years [interquartile range,
53–71], 87% men, 85% hypertension, 51% hyperlipidemia, 56% smokers).
Inherited aortopathies, moderate to severe aortic regurgitation, and severe
aortic stenosis were seen in 7%, 18%, and 2%, whereas 91% and 54% were
on β-blockers and angiotensin-converting enzyme inhibitors, respectively.
Aortic root area/height ratio was ≥10 cm2/m in 24%. The Society of
Thoracic Surgeons score and right ventricular systolic pressure were 3.3±3
and 31±7 mm Hg, respectively. At 7.8 years (interquartile range, 6.6–8.9),
280 (36%) patients underwent aortic surgery (76% within 1 year) and 130
(17%) died (1% in-hospital postoperative mortality). A lower proportion of
patients in the surgical (versus nonsurgical) group died (13% versus 19%,
P<0.01). On multivariable Cox proportional hazard analysis, aortic root area/
height ratio (hazard ratio, 4.04; 95% confidence interval [CI], 2.69–6.231)
was associated with death, whereas aortic surgery (hazard ratio, 0.47;
95% CI, 0.27–0.81) was associated with improved survival (both P<0.01).
For longer-term mortality, the addition of aortic root area/height ratio ≥10
cm2/m to a clinical model (Society of Thoracic Surgeons score, inherited
aortopathies, hypertension, hyperlipidemia, medications, aortic regurgitation,
and right ventricular systolic pressure), increased the c-statistic from 0.57
(95% CI, 0.35–0.77) to 0.65 (95% CI, 0.52–0.73) and net reclassification
index from 0.17 (95% CI, 0.02–0.31) to 0.23 (95% CI, 0.04–0.34), both
P<0.01. Of the 327 patients with aortic root diameter between 4.5 and 5.5
cm, 44% had an abnormal aortic root area/height ratio, of which 78% died.

CONCLUSIONs:

In patients with dilated aortic root and trileaflet aortic
valve, a ratio of aortic root area to height provides independent and
improved stratification for prediction of death.

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Molecular Signature of Acute Myocardial infarction

An Eric Topol tweet provided public access to a very interesting paper. Candidate genes from circulating endothelial cells were identified and comparison between AMI and healthy controls. The model developed was then tested in a replication/validation set.

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Journal Club 23 October 2013

Paper

Feasibility of Single-Beat Full-Volume Capture Real-Time Three-Dimensional Echocardiography and Auto-Contouring Algorithm for Quantification of Left Ventricular Volume: Validation with Cardiac Magnetic Resonance Imaging

Presenter

SP

Summary

Background:

With recent developments in echocardiographic technology, a new system using real-time threedimensional
echocardiography (RT3DE) that allows single-beat acquisition of the entire volume of the left
ventricle and incorporates algorithms for automated border detection has been introduced. Provided that
these techniques are acceptably reliable, three-dimensional echocardiography may be much more useful
for clinical practice. The aim of this study was to evaluate the feasibility and accuracy of left ventricular (LV)
volume measurements by RT3DE using the single-beat full-volume capture technique.

Methods:

One hundred nine consecutive patients scheduled for cardiac magnetic resonance imaging and RT3DE
using the single-beat full-volume capture technique on the same day were recruited. LV end-systolic volume, enddiastolic
volume, and ejection fraction were measured using an auto-contouring algorithm from data acquired on
RT3DE.Thedatawerecomparedwiththe samemeasurementsobtainedusingcardiacmagnetic resonance imaging.
Results: Volume measurements on RT3DE with single-beat full-volume capture were feasible in 84% of patients.
Both interobserver and intraobserver variability of three-dimensional measurements of end-systolic
and end-diastolic volumes showed excellent agreement. Pearson’s correlation analysis showed a close correlation
of end-systolic and end-diastolic volumes between RT3DE and cardiac magnetic resonance imaging
(r = 0.94 and r = 0.91, respectively, P < .0001 for both). Bland-Altman analysis showed reasonable limits of
agreement. After application of the auto-contouring algorithm, the rate of successful auto-contouring (cases
requiring minimal man
ual corrections) was <50%.

Conclusions:

RT3DE using single-beat full-volume capture is an easy and reliable technique to assess LV volume
and systolic function in clinical practice. However, the image quality and low frame rate still limit its
application for dilated left ventricles, and the automated volume analysis program needs more development
to make it clinically efficacious.