Lp(a) and evolution of left anterior descending velocity reserve in stable coronary artery disease: Is there anything beyond dobutamine stress echo outcome?

Abstract

Abstract Funding Acknowledgements Type of funding sources: None. Background Elevated Lp(a) is related with premature and accelerated atherosclerosis, thus confering increased risk for incident chronic coronary disease (CAD) and adverse outcome. Dobutamine stress echo (DSE) and coronary flow reserve (CFR) are both related with incident CAD and outcome as well. Purpose Aim of the study was to evaluate the potential relationship between Lp(a) and DSE outcome/left anterior descending (LAD) based CFR in chronic CAD. Methods 132 consecutive pts (age 59±11years, 18 females, 33 diabetics) with stable CAD were studied by DSE with a concomitant evaluation of LAD CFR. Lp(a) distribution was positive skewed (median 18.6 mg/dL) and it was then normalized by log transformation (logLpa: 2.9±1.1). High and low Lpa groups (LpaH/LpaL: 30/92) were defined using the conventional cut off 50 mg/dL. Sixty-eight/132 pts had a follow up DSE with concomitant revaluation of CFR at 98±74 months. Absolute and % changes (%d) of LAD CFR were estimated. Results LpaH and LpaL groups had similar baseline: CFR (2.4±0.5 vs 2.4±0.6), %dCFR (0.33±0.7 vs 0.35±0.8), creatinine (0.98±0.18 vs 1.0±0.26), HbA1c (5.3±0.9 vs 5.3±1.0) and high sensitivity C reactive protein (2.8±2.7 vs 2.6±2.8mg/L). LpaH had lower baseline LDL (93±31 vs 111±50 p = 0.04). LpaH and LpaL groups had also similar hemodynamic burden at DSE and incidence of positive DSE. LpaH nondiabetics had a trend for more nonLAD distribution of ischemia (odds ratio=1.8, p = 0.07) with a greater incidence of previous revascularization (odds ratio=2.3, p = 0.03). Further clustering based on optimal CAD treatment achieved at baseline (guidelines achieved optimal resting heart rate and LDL) did not change the findings. However, improvement in %d LAD CFR during follow up was inversely related with logLpa (figure: R2=0.09 p = 0.05). A similar trend for %d LAD CFR and logLpa was evident for a follow up period shorter than 100 months. Conclusion In chronic CAD, high Lpa levels in the absence of diabetes are related with greater incidence of DSE ischemia. Despite similar CFR baseline values between conventionally defined high and low Lpa groups, the evolution of LADCFR during long term follow up is affected consistently on time by the baseline logLpa. These findings support a potential role of Lpa on ischemic burden and microvascular function in the time domain of CAD.