An easy and reproducible parameter for the assessment of the pressure gradient in patients with aortic stenosis disease: A magnetic resonance study.

AIM: Cardiovascular magnetic resonance (CMR) has been increasingly used as an alternative method to evaluate the severity of aortic stenosis. The aim of our study was to evaluate whether the indirect measurement of the aortic gradient (Calc-PG), derived from Gorlin's formula, is a reproducible parameter for gradient assessment. Then, we evaluated if this parameter is correlated with left ventricular hypertrophy, considered as a marker of severity of aortic stenosis, better than phase-contrast sequences-derived pressure gradient (PC-PG) and aortic valve area. METHODS: Forty-one patients with isolated aortic stenosis underwent CMR. Calc-PG was obtained from the formula (cardiac output/aortic valve area)(2), and it was compared to PC-PG. RESULTS: We found that the Calc-PG has higher correlation with left ventricle mass than PC-PG (r(2) 0.44, p<0.001 vs. r(2) 0.26, p<0.01), also after multivariate analysis adjusting for age, gender and hypertension (p<0.001). Furthermore, Calc-PG was more reproducible than PC-PG. The receiver operating characteristic comparison curve analysis showed that Calc-PG has a significantly higher ability to describe the presence of left ventricular hypertrophy than PC-PG (area under the curve 0.85, 95% CI 0.70-0.94, p<0.0001 vs. 0.74, 95% CI 0.58-0.87, p=0.03). CONCLUSIONS: We propose that transaortic gradient indirectly calculated by using the simplified Gorlin's equation could be an alternative method to assess the severity of aortic stenosis.

Cardiac magnetic resonance evaluation of the impact of interventricular and intraventricular dyssynchrony on cardiac ventricular systolic and diastolic function in patients with isolated left bundle branch block.

Ventricular dyssynchrony significantly impairs cardiac performance. However, the independent role of interventricular dyssynchrony (interVD) and intraventricular dyssynchrony (intraVD) in the development of abnormalities of systolic and diastolic performance is unclear. Cardiac magnetic resonance imaging was performed in 39 patients with left bundle branch block and 13 healthy patients. Structural and functional parameters of the left ventricle and degrees of interVD and intraVD were measured. We found that interVD was inversely correlated with left ventricular (LV) ejection fraction (r = -0.8, p <0.0001) and positively correlated with LV end-diastolic volume (r = 0.4, p <0.01), LV end-systolic volume (r = 0.6, p <0.0001), and LV mass (r = 0.4, p <0.01), thus indicating that interVD significantly affects systolic function and favors ventricular remodeling. Multivariate analysis further confirmed that interVD was an independent predictor of systolic dysfunction. Interestingly, we found that interVD was not associated with abnormalities of diastolic performance. Conversely, we found that intraVD significantly impaired diastolic function, whereas it had no effect on systolic function. IntraVD was inversely correlated with peak filling rate (r = -0.7, p <0.0001) and 1/2 filling fraction (r = 0.4, p = 0.04) and positively correlated with time to peak filling rate (r = 0.6, p <0.0001), validated parameters of diastolic function. Multivariate analysis confirmed that intraVD was an independent predictor of diastolic dysfunction. In conclusion, our study suggests that the 2 components of ventricular dyssynchrony differently affect cardiac performance. If confirmed in prospective studies, our results may help to predict the prognosis of patients with left bundle branch block and different degrees of interVD and intraVD, particularly those subjects undergoing cardiac resynchronization therapy.