Left ventricular function in the Marfan syndrome without significant valvular regurgitation.

Assessment of left ventricular (LV) size and function in many patients with the Marfan syndrome is confounded by the presence of aortic or mitral regurgitation. Therefore, we sought to determine LV size and function in a cohort of patients with the Marfan syndrome who had only mild or no aortic or mitral valve regurgitation. ••• Of the 128 patients in the Mayo Clinic Marfan database who met the Gent diagnostic criteria for the Marfan syndrome, 1 36 (23 males) had no or only mild aortic and mitral valve regurgitation noted on the first complete echocardiogram recorded at our institution. These 36 patients formed the study cohort. M-mode measurements derived from the echocardiogram for these patients included LV end-diastolic dimension (EDD), LV endsystolic dimension (ESD), and ejection fraction. Dimensions were indexed to age and body surface area to allow comparison with previously published normal values. 2,3 These measurements were recorded from the first and the most recent echocardiogram to determine any changes in LV dimensions and function that occurred over time. Associations between LVEDD and mitral valve prolapse or aortic root dilation were evaluated to determine if patients with mitral valve prolapse or aortic root dilation had higher LVEDD than those without these syndromes. The predicted normal value and the corresponding range for LVEDD and LVESD were calculated for each patient according to their age and body surface area using regression equations 2,3 previously developed for that purpose. The observed dimensions then were scaled relative to the predicted normal value, and reported as the percentage of the corresponding mean predicted dimension. The resulting values that were reported correspond to the observed dimension divided by the predicted normal value 100. The 95% confidence intervals of the averages of these rescaled dimensions were calculated using the formula: mean tn1, 0.025 SE, where tn1, 0.025 is the 2-sided critical value obtained from the t distribution with n1 degrees of freedom. For each dimension, the number of patients having an observed dimension beyond the predicted normal range was tabulated. Exact 95% confidence intervals were calculated for the percentage of patients with extreme observed dimensions using the binomial distribution. Exact binomial tests were used to compare the percentage of extreme values to the 5% extreme values that would be expected in a normal population. The association between LVEDD and mitral valve prolapse or aortic root dilation was assessed using a 2-sample t test. To compare the dimensions on the first and the last echocardiogram, values were scaled relative to the predicted normal range, given the age and body surface area, using the formula: scaled value (observed predicted normal for the given age and body surface area)/(half-width of normal range). These scaled values provide a measure of how extreme the observed dimension is relative to the entire normal predicted range. The scaled values on the first and last echocardiograms were compared using paired t tests. A 2-sided p value 0.05 was considered statistically signi ficant.