title: Residual compromised myocardial contractile reserve after valve replacement for aortic stenosis.
abstract: OBJECTIVE
  Despite recovery of left ventricular (LV) function and morphology after aortic valve replacement (AVR) for aortic stenosis (AS), its relationship with exercise capacity remains unknown. Twenty-one AVR patients (age 61 ± 12 years, 14 male) with normal ejection fraction (EF, 64 ± 7%) and 21 age- and sex-matched controls (57 ± 9 years, 10 male, EF 68 ± 8%) were studied.
  
  
  RESULTS
  All subjects performed semi-supine bicycle exercise and speckle tracking echocardiography (STE) study. Peak oxygen consumption (pVO(2)) was collected during semi-supine bicycle exercise. Systolic (GLSRs) and early diastolic (GLSRe) longitudinal strain rate using STE and Doppler echocardiographic parameters were measured at rest, submaximal, peak exercise, and 4 min after exercise. The two groups had comparable resting echocardiographic measurements. At peak exercise, pVO(2) was lower in patients than controls (18.5 ± 4.5 vs. 22.1 ± 4.3 L/min/kg, P < 0.05). GLSRs (0.98 ± 0.28 vs. 1.55 ± 0.30 1/s, P < 0.001), septal Sm (7.9 ± 1.4 vs. 11.1 ± 2.3 cm/s, P < 0.001) and their changes between rest and peak exercise (ΔGLSRs: 0.16 ± 0.33 vs. 0.68 ± 0.27 1/s, P < 0.001; ΔSm 2.29 ± 2.23 vs. 4.63 ± 2.29 cm/s, P < 0.01) were significantly lower in patients than controls. There was no correlation between pVO(2) and any echocardiographic measurements in controls. In patients, pVO(2) correlated with peak exercise GLSRs (r = 0.60, P = 0.0007), septal Sm (r = 0.65, P = 0.002), and Em (r = 0.57, P = 0.009). In a multivariate model, peak exercise GLSRs (β = 7.18, P = 0.03) was the only independent predictor of pVO(2) in the patients group.
  
  
  CONCLUSIONS
  Exercise capacity is subnormal after AVR for AS, irrespective of normal LVEF suggesting residual compromised myocardial functional reserve.
authors.affiliation: Heart Centre,  Umeå University, Umeå,  Sweden.
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhao
authors.forename: Michael Y
authors.initials: MY
authors.lastname: Henein
authors.forename: Stellan
authors.initials: S
authors.lastname: Mörner
authors.forename: Sandra
authors.initials: S
authors.lastname: Gustavsson
authors.forename: Anders
authors.initials: A
authors.lastname: Holmgren
authors.forename: Per
authors.initials: P
authors.lastname: Lindqvist
mesh_terms: D001024:Aortic Valve Stenosis / Q000000981:diagnostic imaging* / Q000473:pathology; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D003971:Diastole; D017079:Exercise Tolerance; D005260:Female; D006305:Health Status Indicators; D019918:Heart Valve Prosthesis Implantation / Q000009:adverse effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction; D009206:Myocardium; D010101:Oxygen Consumption; D013223:Statistics as Topic; D013318:Stroke Volume; D013599:Systole; D013997:Time Factors; D014463:Ultrasonography; D016277:Ventricular Function, Left