Natural history of aortic valve disease following intervention for rheumatic mitral valve disease.

BACKGROUND AND AIM OF THE STUDY

A significant proportion of patients who require interventions for rheumatic mitral valve (MV) disease have coexisting aortic valve (AV) disease. To date, little is known of the natural history of AV disease in these patients.

METHODS

The details of a cohort of 200 patients (146 females, 54 males; mean age at MV intervention 30.3 +/- 9.9 years) with rheumatic heart disease were retrospectively reviewed. The patients had undergone an index MV intervention (either closed or balloon mitral valvotomy) or MV replacement between 1994 and 1996, and received long-term regular follow up examinations. The clinical and echocardiographic data at entry and at follow up were noted. Patients were allocated to two groups, based on whether the AV disease was absent (group I, n=98) or present (group II, n=102) at baseline. The AV disease was categorized as thickening only (group IIA), isolated aortic regurgitation (AR) (group IIB), or combined aortic stenosis (AS) and AR (group IIC). No patient had isolated AS at baseline.

RESULTS

The mean follow up period was 9.3 +/- 1.07 years; during which 10 patients in group I developed new AV disease, which included AV thickening only (n=2), trivial-mild AR (n=7) and mild AS with trivial AR (n=1). Of 16 patients in group IIA, 11 developed isolated AR, and one patient progressed to have mild AS and AR. Among 69 patients in group IIB, 22 (31.9%) developed AS, and all had either mild (n=8) or moderate (n=14) AR with mild AS. Group IIC included 17 patients with mild combined AV disease at baseline, except for moderate AS and moderate AR in one patient each. Among 16 patients with mild AS in group IIC, six progressed to moderate AS and two to severe AS. AR became moderate in 10 patients and severe in one patient. The two patients who progressed to severe AS requiring AV replacement had mild AS at baseline. No patient who developed new combined AV disease had lesions with severity more than mild AS or moderate AR. On logistic regression analysis of the variables predisposing to progression of AV disease, such as age, gender, history of rheumatic fever (RF) and recurrence, and interval from RF episode to symptom onset, only the initial AV gradient was identified as being statistically significant (beta coefficient 0.528, SE = 0.17, p < 0.0001).

CONCLUSION

Patients with no or mild AV disease at the time of MV intervention rarely develop severe AV disease, and seldom require AV surgery over the long-term follow up. The presence of mild AS at baseline is predictive in the minority of cases where AV disease will progress relatively more rapidly.