title: Value of the mitral valve resistance in evaluation of symptomatic patients with mild and moderate mitral stenosis--a dobutamine stress echocardiographic study.
abstract: BACKGROUND
  Conventional stenosis indexes poorly reflect the major hemodynamic consequence of mitral stenosis (MS). Valve resistance (VR) is a physiologic expression of stenosis.
  
  
  OBJECTIVE
  This study aimed to demonstrate whether the mitral valve resistance (MVR) and its changes, relate to restricted exercise capacity in patients with mild and moderate mitral stenosis.
  
  
  METHODS
  Twenty-four patients with rheumatic mild-to-moderate MS underwent transthoracic echocardiographic study (resting and dobutamine stress echocardiography [DSE]), divided into two groups; group I: symptomatic (12 patients) and group II: asymptomatic (12 patients). Mitral valve area (MVA), mean transmitral diastolic pressure gradient (TMPG), cardiac output (CO), and MVR were measured in all patients at rest and at peak DSE. Changes (∆) in MVA, TMPG, CO, and MVR were calculated. Data underwent statistical analysis.
  
  
  RESULTS
  From resting to peak dobutamine infusion, the MVR significantly decreased from 111.4 ± 28.2 to 83.6 ± 27.0 dynes sec/cm(5) in group II (P < 0.001). The increase in MVR in group I (13.8 ± 10.3 dynes sec/cm(5)) compared with its reduction (-27.8 ± 15.6 dynes sec/cm(5)) in group II were highly significant different (P < 0.001). A reduction in MVR by less than 21.5 dynes sec/cm(5) at peak dobutamine infusion reflect a cutoff value considered to detect the hemodynamic significance of mild-to-moderate MS with a sensitivity of 92% and a specificity of 73%.
  
  
  CONCLUSIONS
  The changes in the MVR can be used as a DSE parameter for expression of stenosis severity and to describe discrepancy in symptom status in patients with mild-to-moderate mitral stenosis.
authors.affiliation: Cardiology Department, Faculty of Medicine, Zagazig University, Zagazig, Egypt.
authors.forename: Hisham S
authors.initials: HS
authors.lastname: Roshdy
authors.forename: Amir M
authors.initials: AM
authors.lastname: Meshrif
authors.forename: Ibtesam I
authors.initials: II
authors.lastname: El-Dosouky
mesh_terms: D000328:Adult; D002302:Cardiac Output / Q000502:physiology*; D016009:Chi-Square Distribution; D015331:Cohort Studies; D004452:Echocardiography / Q000379:methods; D025401:Echocardiography, Stress / Q000379:methods*; D005260:Female; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D008946:Mitral Valve Stenosis / Q000000981:diagnostic imaging* / Q000503:physiopathology; D011379:Prognosis; D011446:Prospective Studies; D012372:ROC Curve; D012214:Rheumatic Heart Disease / Q000000981:diagnostic imaging / Q000503:physiopathology; D012720:Severity of Illness Index; D018709:Statistics, Nonparametric; D055815:Young Adult
keywords: dobutamine stress echocardiography; hemodynamic consequence of mitral stenosis; mitral stenosis; mitral valve resistance