Predicting Outcomes in Patients With a Trileaflet Aortic Valve and Dilated Aorta
In patients with a dilated proximal ascending aorta and a trileaflet aortic valve, what are the factors associated with adverse outcomes and what is the incremental prognostic utility of indexing aortic root (for ascending aorta) to the patient’s height?
This was a retrospective observational study of 771 consecutive adult patients at a tertiary care center. Patients were included if: 1) a dilated (≥4 cm) aortic root and/or ascending aorta was identified on an initial transthoracic echocardiogram, and 2) either a contrast-enhanced computed tomographic angiogram or a contrast-enhanced magnetic resonance angiogram confirmed the measurements from echocardiography. Surgical procedures and time to surgery were recorded. All-cause death was the primary outcome.
A total of 280 (36%) patients underwent cardiovascular surgery involving the aortic root and/or ascending aorta during follow-up, at a median time of 16 days. Over a median follow-up of 7.3 ± 2.6 years, there were a total of 130 deaths with no patients lost to follow-up. The proportion of deaths was significantly higher in the group with aortic root area/height ratio ≥10 cm2/m versus those <10 cm2/m (33% vs. 12%, p < 0.001). On multivariable Cox proportional hazard analysis, aortic root area/height ratio (hazard ratio [HR], 4.04; 95% confidence interval [CI], 2.69-6.23) was associated with death. For longer-term mortality, addition of aortic root area/height ratio ≥10 cm2/m to a clinical model (Society of Thoracic Surgeons [STS] score, inherited aortopathies, hypertension, hyperlipidemia, medications, aortic regurgitation, and right ventricular systolic pressure) increased the c-statistic from 0.57 (CI, 0.35-0.77) to 0.65 (CI, 0.52-0.73).
In patients with a dilated aortic root and trileaflet aortic valve, a ratio of aortic root area to height is an independent predictor of death.
While limited by its retrospective design, this is a valuable study that draws attention to the possibility that aortic root area/height ratio >10 cm2/m has significant and independent prognostic utility. Interestingly, the authors demonstrated that 44% of patients with aortic root diameters between 4.5 and 5.5 cm (generally below the threshold where pre-emptive surgery is recommended) had an abnormal aortic root/height ratio. As the authors acknowledge, their findings require prospective validation.
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