Association of Myocardial Deformation With Outcome in Asymptomatic Aortic Stenosis With Normal Ejection Fraction

Abstract

Background-Current guidelines recommend intervention for symptomatic aortic stenosis, but the management of asymptomatic aortic stenosis remains controversial. As left ventricular global longitudinal strain (GLS) has been shown to predict cardiovascular outcome, we sought to find whether its use could guide the assessment of risk in these patients. Methods and Results-We prospectively followed 79 patients with severe asymptomatic aortic stenosis (39 men; mean age, 77 ± 12 years; aortic valve [AV] area index, 0.36 cm 2 /m 2 ). In addition to standard echocardiography, speckle strain was measured to assess GLS. Patients were followed for cardiac death and AV replacement driven by symptom development. A multivariable Cox regression was performed to identify associations with events. During 23 ± 20 months, 3 patients had cardiac death and 49 underwent AV replacement. Event-free survival was 72 ± 5% at 1 year, 50 ± 5% at 2 years, and 24 ± 5% at 4 years. Death and AV replacement were predicted by GLS (hazard ratio [HR] Methods Patient SelectionThe study population included patients with severe AS who were studied in our echocardiography laboratory from March 2004 to August 2010. Severe AS was defined as AV area <1 cm 2 or transaortic jet velocity >4 m/s. Patients were excluded if they had any additional hemodynamically significant valvular lesions, presented with symptoms (angina, dyspnea, or syncope) or LV ejection fraction (LVEF)<50%. After these exclusions, we enrolled 79 patients (39 men; 77 ± 12 years; AV area index, 0.36 cm 2 ). The protocol was approved by the institutional review board of the Cleveland Clinic. Clinical CharacteristicsClinical data were entered prospectively into an electronic health record, including age, sex, height, weight, history of coronary artery disease (previous positive coronary angiogram or stress test), history of diabetes mellitus (fasting blood glucose >126 mg/dL on 2 occasions or patients currently receiving treatment for diabetes mellitus), history of hypercholesterolemia (total cholesterol >190 mg/dL or patients receiving lipid lowering agents), history of hypertension (blood pressure ≥140/90 mm Hg or patients receiving antihypertensive drugs) were collected at baseline. The Society of Thoracic Surgeons (STS) Predicted Risk of Morbidity or Mortality (STS-PRMM) for AV procedures was calculated by entering patient data into an online STS risk calculator (http://riskcalc.sts.org/ STSWebRiskCalc273/). The STS-PRMM uses 24 variables of >50 total risk factors collected by algorithm to predict mortality for valve procedures. 17 EchocardiographyPatients underwent a standard echocardiogram performed by experienced echocardiographers, using commercially available ultrasound systems. The LV dimensions, wall thickness, and outflow tract diameter were measured according to the recommendations of the American Society of Echocardiography. 18 The degree of calcification of the AV was scored as: (1) no calcification; (2) mildly calcified (small isolated foci); (3) moderately calcified (multipl...

Effect of Left Ventricular Ejection Fraction on Postoperative Outcome in Patients With Severe Aortic Stenosis Undergoing Aortic Valve Replacement

“…In a recent publication, we demonstrated that reduced longitudinal LV function was associated with a poor postoperative outcome in patients with AS and LVEF≥40% undergoing AVR. 15 Similar findings have since been demonstrated in asymptomatic patients with AS 16 and AS patients with LVEF≥50%. 17 The findings from these small cohort studies have been attributed to the improved ability of global longitudinal strain in detecting early stages of LV systolic impairment, as reduced longitudinal function is known to precede reduced circumferential function.…”

Impact of Flow and Left Ventricular Strain on Outcome of Patients With Preserved Left Ventricular Ejection Fraction and Low Gradient Severe Aortic Stenosis Undergoing Aortic Valve Replacement

“…6,13,14 Patients were also categorized as having an LV global longitudinal strain ≤-15% or >-15%. 7, [15][16][17] The end-point of the study was all-cause mortality. All patients were followed-up after AVR.…”

Outcomes in Asymptomatic Severe Aortic Stenosis With Preserved Ejection Fraction Undergoing Rest and Treadmill Stress Echocardiography

“…Therefore, objective and reproducible parameters that identify early LV dysfunction, before a drop in LVEF could potentially allow more appropriate timing of surgery and in turn, allow improved survival. Over the past decade, the relationship between global LV load and abnormal LV systolic performance in AS patients, even in those with preserved LVEF has become more apparent, and the use of novel echocardiographic measures of LV load (Zva)19, 20, 45 and LV systolic performance (LV‐GLS)18, 30, 46 have been proposed as potential markers of early dysfunction, providing incremental prognostic utility.…”

“…In addition, exercise‐induced drop in systolic blood pressure is a Class IIa indication for surgery1, 2 However, these recommendations are based upon multiple small reports with heterogeneous end points3, 9, 10, 11, 12, 13, 14, 15 In a recent study, we have demonstrated that in asymptomatic patients with severe AS and preserved left ventricular ejection fraction (LVEF), only 50% achieved 100% of age‐sex predicted exercise capacity; with exercise stress testing providing significant reclassification of longer‐term mortality risk16 In the past decade, novel echo parameters including reduced left ventricular global longitudinal strain (LV‐GLS)17, 18, 19 and valvuloarterial impedance (Zva)17, 19, 20 have also been associated with worse prognosis in patients with asymptomatic severe AS. However, no study has systematically evaluated the incremental prognostic impact of resting Zva and LV‐GLS on data obtained from exercise stress testing in patients with asymptomatic severe AS and preserved LVEF.…”