Role of estimated aortic pulse wave velocity in the prediction of future thoracic aortic aneurysm expansion

Abstract

Abstract Background Thoracic aortic aneurysm (TAA) is a deadly disease in critical need of novel strategies for risk assessment and medical management. To address this need, we have previously shown that directly measured carotid-femoral pulse wave velocity (cfPWV), a marker of aortic stiffness and health, independently predicts future TAA expansion. Since aortic pulse wave velocity can be estimated from age and mean arterial pressure (MAP), in the present study we sought to determine whether estimated aortic pulse wave velocity (e-aPWV) also predicts TAA expansion. Methods One hundred and five consecutive, unoperated subjects with TAA were recruited. e-aPWV was estimated from validated equations based on age and MAP. cfPWV was measured with arterial tonometry according to guidelines. TAA size was measured at baseline and at the latest follow-up using available imaging modalities according to guidelines. Stepwise multivariable linear regression (P≤0.25 to enter, P≤0.10 to stay in the model) assessed independent associations of e-aPWV and cfPWV with future TAA growth. Variables considered in the models were: age, sex, BSA, MAP, TAA etiology and location, baseline TAA size, follow-up time, imaging modality, history of hypertension, diabetes and smoking. Results Seventy eight percent of subjects were men. Mean±SD age, baseline aneurysm size and follow-up time were 62.6±11.4 years, 46.2±3.8 mm and 3.0±1.0 years, respectively. e-aPWV and cfPWV were moderately correlated (Pearson's correlation coefficient = 0.61). Results of the linear regression analyses showed that both measured (cfPWV) and estimated (e-aPWV) independently predicted future TAA expansion (β±SE: 0.032±0.011, P=0.048 and 0.240±0.085, P=0.006, respectively). The base model's R-squared value of 0.39 was increased to 0.44 with addition of either cfPWV or e-aPWV to the model, confirming that each parameter of aortic stiffness enhances prediction of TAA growth. Conclusion Aortic stiffness is relevant for assessment of TAA disease activity. Similar to cfPWV, e-aPWV is also independently associated with future TAA expansion. Thus, e-aPWV represents a tool to improve TAA risk stratification that is simple, free of cost, and obviates the need for specialized equipment or dedicating training, which leads to excellent potential for widespread incorporation into clinical practice. Funding Acknowledgement Type of funding source: Public grant(s) – National budget only. Main funding source(s): Canadian Institutes of Health Research