P334Imaging of expiratory gas exchange in detection of diastolic dysfunction in patients with hypertension : Combined stress echocardiography cardiopulmonary exercise testing


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Abstract

Background: Exertional dyspnea and exercise intolerance are a common symptoms in patients with hypertension due to development of hypertensive heart disease and diastolic dysfunction even in patients with preserved LV systolic function. Transmitral flow and tissue Doppler improved the diagnosis and stratification of diastolic impairment significantly. However, simple diagnosis and stratification of patients according to severity of diastolic dysfunction at rest is not accurate without estimation of functional significance of such impairment during cardiopulmonary exercise testing (CPET). However, relationship between diastolic function and CPET during combine stress echo CPET is still unknown.Objective: To determine the usfulness of combined Stress echo CPET in evaluation of patients with hypertension, exertional dyspnea and normal baseline systolic and diastolic function.Methods: We studied 47 pts (28 male, mean age 51±14 years), with the history of essential hypertension, exertional dyspnea and normal baseline echo characteristics (including normal baseline systolic and diastolic function). They all underwent CPET with supine ergometer with incremental ramp protocol, with breath by breath gas analysis, in combination with simultaneous 2D echocardiographic monitoring during exercise. Diastolic function was assessed by analyzing transmitral flow pattern using pulse Doppler and tissue Doppler (TDI) of mitral annulus. Mitral E wave / E wave of mitral annulus ≥ 8 was cut off for diastolic function.Results: Worsening of diastolic function was found in 13 (38%) pts during combined CPET stress echo test. Patients with diastolic dysfunction were older (p=0.001), and had lower peak VO2 (p=0.0001), shorter time to VAT (p=0.028) and shorter total exercise time (p=0.017), and higher VE/VCO2 slope (p=0.0001). However multivariant analysis showed that only VE/VCO2 was independant predictor of diastolic dysfunction during CPET (p=0.001; RR 1.68; 95%CI : 1.24 -2.24). We also found the strong correlation between VE/VCO2 slope and E/Em ( r=0.70; p=0.0001) which can be also used for stratification of pts with diastolic dysfunction.Conclusion: Combined CPET stress echocardiography as a new test improves clinical assessment of diastolic function in patients with exertional dyspnea and normal baseline LV function. It adds more information to echocardiography and to CPET as a single tests. The best predictor of development of diastolic dysfunction during CPET was VE/VCO2 slope, showing the strong relationship with E/Em as a measure of diastolic function.

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