Abstract 3159: The Ratio of Pulse Pressure/Stroke Volume index, a Marker of Total Arterial Compliance: Its Correlation with Abnormal Left Ventricular Geometry
Introduction: An increase in the ratio of pulse pressure/stroke volume index (PP/SVi) implies worsening arterial compliance and predicts adverse cardiovascular events. It also correlates with left ventricular hypertrophy. However, the degree to which it correlates with the various subtypes of abnormal LV geometry remains to be fully elucidated.
Hypothesis: We hypothesized that an increase in PP/SVi is seen specifically in abnormal concentric LV geometry as opposed to eccentric hypertrophy (EH). In addition, the degree to which the index correlates with increases in relative wall thickness (RWT) depends on the presence of concentric remodeling (CR) vs concentric hypertrophy (CH).
Methods: We reviewed 480 echocardiograms from subjects with EF >/= 50% and lack of valvular dysfunction. LV geometry was based on RWT and mass indexed for BSA (LVMi). RWT = (2 X posterior wall thickness)/left ventricular internal diastolic diameter (M-mode, parasternal views). CR equaled RWT >/= 45% and normal LVMi (males < 125g/m2; females < 110 g/m2); CH equaled RWT >/= 45% and increased LVMi; and EH equaled an increased LVMi and normal RWT. SVi was based upon end-systolic and end-diastolic volumes as calculated by the Teicholz formula (indexed for BSA) and PP was obtained via sphygmomanometry.
Results: For subjects with normal geometry (n = 163), RWT = 0.37 +/− 0.02 (mean +/− SEM), PP/SVi = 1.10 +/− 0.03 (mmHg*m2/ml) and MAP = 90 +/− 0.51(mmHg); with CR (n = 144), RWT = 0.53 +/− 0.02, PP/SVi = 1.72 +/− 0.02 and MAP = 95 +/− 0.61; for CH (n = 125), RWT = 0.54 +/− 0.01, PP/SVi = 1.35 + /− 0.03 and MAP = 95+/− 0.56; for EH (n = 48), RWT = 0.40 +/− 0.01, PP/SVi = 1.06 +/− 0.01 and MAP = 96 +/− 0.60. (p < 0.01 for PP/SVi normal vs CR vs CH; p < 0.01 for RWT CR and CH vs Normal and EH)
Conclusion: The PP/SVi ratio is increased in abnormal concentric LV geometry, correlating with the increase in RWT. However, the degree in which RWT increases as a proportion of the PP/SVi is markedly greater in CH as opposed to CR (despite similar arterial pressure). This difference unmasks CH as a state in which there is an excess increase in RWT in relation to the total arterial compliance burden. In patients with EH, PP/SVi remains within the normal range and suggests that the stimulus for hypertrophy is not a function of worsening arterial compliance.