Aortic Cross-Sectional Area/Height Ratio and Outcomes in Patients with a Trileaflet Aortic Valve and a Dilated Aorta
Background—In patients with a dilated proximal ascending aorta and trileaflet aortic valve (TAV), we sought to assess a) factors independently associated with increased long-term mortality and b) 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 2003-2007. A ratio of aortic root area over height was calculated (cm2/m) on tomography, and a cutoff of10 cm2/m was chosen as abnormal, based on 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-severe aortic regurgitation (AR) and severe aortic stenosis were seen in 7%, 18% and 2%, while 91% and 54% were on betablockers and angiotensin converting enzyme inhibitors, respectively. Aortic root area/height ratio was ≥10 cm2/m in 24%. The Society of thoracic surgeons (STS) score and right ventricular systolic pressure (RVSP) 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 (vs. nonsurgical) group died (13% vs. 19%, p-value<0.01). On multivariable Cox proportional hazard analysis, aortic root area/height ratio (hazard ratio [HR] 4.04 [95% confidence interval-CI-2.69-6.231]) was associated with death, while aortic surgery (HR 0.47 [CI 0.27-0.81]) was associated with improved survival (both p<0.01). For longer-term mortality, addition of aortic root area/height ratio ≥10 cm2/m to a clinical model (STS score, inherited aortopathies, hypertension, hyperlipidemia, medications, AR and RVSP), increased the c-statistic from 0.57 [CI 0.35-0.77] to 0.65 [0.52-0.73] and net reclassification index from 0.17 (0.02-0.31) to 0.23 [0.04-0.34], both p<0.01. Of the 327 patients with aortic root diameter between 4.5-5.5 cm, 44% had an abnormal aortic root area/height ratio of which 78% died.
Conclusions —In patients with dilated aortic root and TAV, a ratio of aortic root area to height provides independent and improved stratification for prediction of death.
- Received April 14, 2016.
- Revision received August 29, 2016.
- Accepted September 28, 2016.