Echocardiographic surveillance of aortic valve stenosis: towards a standardized approach

Severe symptomatic aortic stenosis (AS) portends a poor prognosis, and there is growing evidence that even mild disease carries significant morbidity. Systematic echocardiographic monitoring of asymptomatic disease is therefore essential to optimize the effectiveness of interventions. Inconsistencies exist, however, between different guidelines, and this may lead to inefficient resource utilization or, conversely, to inadequate monitoring. The study aim was to assess the appropriateness of AS surveillance echocardiography at the authors' institution. An additional aim was to document AS progression patterns in a contemporary British population, for which few data currently exist.

British, European, and North American guidelines relating to echocardiographic surveillance of asymptomatic AS were examined. A retrospective analysis of practice at the authors' institution was conducted, with timing of surveillance compared to guidelines. Progression was documented by monitoring the effective orifice area (EOA) and peak pressure gradient (PPG).

Mean progression rates were consistent with published data (deltaEOA = -0.15 +/- 0.49 cm2/year; deltaPPG = +6.67 +/- 24.76 mmHg/year), with wide variation, and poor correlation between surveillance interval and disease progression. Progression of mild AS was significantly faster than severe AS (deltaEOA = -0.33 +/- 0.53 versus +0.04 +/- 0.41 cm2/year, respectively; p < 0.001). Of 169 echocardiograms evaluated, 60.9% were appropriately timed, 33.1% were early, and 6.0% were late. Surveillance of mild AS was less often appropriate than that of moderate or severe AS (12.0% versus 78.3% versus 84.7% appropriate, respectively; p < 0.001). On extrapolating these results nationally, an excess expenditure of pound 4.6 million (US$ 6.0 million) per year was estimated for this indication alone.

Echocardiographic surveillance of asymptomatic AS is often non-compliant with published guidance, which may be attributable to ambiguities and conflicts between different guidelines. The variable natural history of AS necessitates systematic surveillance at all stages of the disease spectrum, which in turn requires unambiguous, standardized guidelines to minimize variation in quality of care, while providing a clear framework to maximize the impact of investigations.