Background and aim of the study: The study aim was to describe the clinical spectrum and mechanism of acute severe mitral regurgitation (MR) observed during first episodes of rheumatic fever (RF), and to identify prognostic factors related to the short-term outcome.
Methods: Since 1990, 44 patients (mean age 9.2 +/- 0.1 years; range: 4-17 years) have been admitted to the authors' institution with severe MR related to a first episode of RF, fulfilling revised Jones' criteria. Twenty-three patients admitted between 1995 and 2002 were included prospectively, and 21 admitted before 1994 were studied retrospectively.
Results: Left ventricular end-diastolic and end-systolic dimensions were 51 +/- 2 mm (46 +/- 3 mm/m2 BSA) and 32 +/- 2 mm (28 +/- 2 mm/m2 BSA), respectively; mean fractional shortening of the left ventricle was 39.0 +/- 1.0% (range: 31-52%); Doppler-derived pulmonary arterial systolic pressure (PAPS) was 51 +/- 6 mm (range: 27-90 mm). The mitral valve annulus was enlarged in all patients (mean diameter 31 +/- 2 mm; 27 +/- 4 mm/m2 BSA). MR resulted from prolapse of the anterior mitral valve leaflet (P of AMVL) in 16 patients (36%), and from prolapse of the posterior mitral valve leaflet (P of PMVL) in nine (20%); the other 19 patients (43%) had restrictive motion of the PMVL, with normal motion of the AMVL, resulting in a 'false prolapse' of the AMVL (FP of AMVL). During the six-month interval following the RF episode, mitral valve surgery was required in 11 patients (25%); three patients (7%) died from cardiogenic shock before they could undergo surgery, while the other 30 patients were stabilized under medical treatment. Using univariate analysis, death or mitral valve surgery was associated with PAPS > 50 mm (OR = 1.7, p = 0.04), male gender (OR = 1.88, p = 0.008), clinical signs of congestive heart failure at admission (OR = 2.7, p < 10(-4)), and prolapse of the PMVL (OR = 5.2, p = 0.01). Death occurred, or mitral valve surgery was necessary, in eight patients with P of PMVL (89%), in four with P of AMVL (25%), and in two with FP of AMVL (11%) (p < 0.001). Despite limitations due to co-linearities and small sample size, multivariate analysis identified P of PMVL as the most potent predictor of adverse outcome. The long-term follow up (mean 6.3 years) of patients without P of PMVL, alive and not operated on during the first six-month interval after an RF episode, demonstrated a sharp decrease in the mean severity of MR (from grade 4 to 1.7; range: 1-3).
Conclusion: In contrast to previous reports of chronic rheumatic MR, acute severe MR due to RF is more frequently related to P of AMVL or P of PMVL, than to FP of AMVL. Patients with P of AMVL or FP of AMVL tend to improve with medical treatment; however, those with P of PMVL carry a poor medical prognosis, and most often require early mitral valve surgery.