Implications of LV Strain Risk Score in Asymptomatic Hypertensive Heart Disease
What is the association of left ventricular (LV) strain as a predictor of cardiac events in patients with hypertensive heart disease (HHD)?
The study population was comprised of 388 asymptomatic patients with HHD who were free of coronary artery disease or significant valvular heart disease. Patients were evaluated between 2005 and 2014. Standard echocardiographic parameters describing LV hypertrophy and ventricular remodeling were obtained. Additionally, global longitudinal strain (GLS) was measured. Patients were followed for major adverse cardiac events (MACE) including death, admission for heart failure, myocardial infarction, or stroke.
Over a median follow-up of 4 years, MACE occurred in 72 patients (19%). On univariate analysis, MACE was associated with older age, atrial fibrillation, concentric LV hypertrophy, larger left atrial volume, and more abnormal GLS. GLS was -15.8 in those with MACE and -16.7 in those without (p < 0.01, hazard ratio, 1.12). In both the clinical model and echocardiographic model, GLS was independently predictive of MACE. Stepwise modeling of clinical parameters, presence of concentric hypertrophy, and GLS revealed statistically significant increases in predictive ability for MACE when comparing clinical, to clinical + concentric hypertrophy, to clinical + concentric hypertrophy + GLS. In the final model, the hazard ratio of GLS was 1.08 per 1% increase in GLS (p = 0.03). A predictive score for MACE was developed, which included 2 points each for atrial fibrillation and age >70 years, and 1 point each for concentric hypertrophy and GLS >-16%. For the overall population, a derivation group and validation group, addition of GLS improved predictive ability compared to concentric hypertrophy alone. In a subset of 55 patients who had a follow-up echocardiogram, more abnormal deterioration in GLS was predictive of MACE.
Lower GLS or deterioration in GLS over time is associated with MACE in asymptomatic patients with HHD. These findings are independent and incremental to clinical parameters and assessment of hypertrophy alone.
GLS and other measures of LV deformation have been shown to be abnormal in a wide variety of cardiovascular diseases, including hypertensive cardiovascular disease. This study in a relatively large number of asymptomatic patients with modest hypertension demonstrates the prognostic value of GLS in this population. Of note, all patients had established hypertension of only modest severity, with an average blood pressure of 145/80 mm Hg. Independent of the presence and nature of LV remodeling, GLS provided further information regarding development of complications including death, stroke, and congestive heart failure. While incrementally significant, the absolute increase in risk was relatively modest, with a hazard ratio of 1.08 per 1% increase in GLS. The degree to which this finding would extrapolate to patients with even milder preclinical hypertensive cardiovascular disease is uncertain; however, in view of its incremental value in this population, consideration of this parameter when considering the impact of hypertension on the cardiovascular system probably deserves consideration. Whether it should play a role in decision making regarding specific forms and intensity of antihypertensive therapy will need to be demonstrated.
Keywords: Antihypertensive Agents, Atrial Fibrillation, Blood Pressure, Diagnostic Imaging, Echocardiography, Heart Failure, Hypertension, Hypertrophy, Left Ventricular, Metabolic Syndrome, Myocardial Infarction, Stroke, Ventricular Remodeling
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