Predicting Outcomes in Patients With a Trileaflet Aortic Valve and Dilated Aorta

Study Questions:

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?

Methods:

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.

Results:

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).

Conclusions:

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.

Perspective:

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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