Objectives: We aimed to identify the bronchial response to inhaled methacholine in patients with mitral stenosis (MS) and to clarify whether or not the bronchial hyperreactivity (BHR) is reversible after percutaneous mitral balloon valvulotomy (PBMV).
Patients and setting: Thirty patients with MS and 28 age-matched healthy control subjects were prospectively evaluated with pulmonary function tests and methacholine challenge. The productive concentration of methacholine causing 20% decrease in FEV(1) (PC(20)) was calculated and used as a parameter of bronchial responsiveness. BHR was defined as a PC(20) < 8 mg/mL. Mean pulmonary artery pressure (PAP) and mean pulmonary capillary wedge pressure (PCWP) were recorded in all patients through a Swan-Ganz balloon-tipped catheter. Sixteen patients underwent PMBV, and a methacholine test was repeated after each procedure.
Results: Bronchial response to methacholine was significantly increased in patients with MS, so that 53% of them had BHR, whereas all control subjects were nonresponders. The PC(20) was closely correlated with the PAP (r = - 0.777; p < 0.001), PCWP (r = - 0.723; p < 0.001), and mitral valve area (MVA; r = 0.676; p < 0. 001). Balloon valvulotomy was successfully performed in all of the 16 patients, and the cardiac parameters (MVA, PAP, and PCWP) significantly improved after the procedure. In contrast, no significant changes were shown in pulmonary function test variables (total lung capacity, vital capacity [VC], FEV(1), and FEV(1)/VC). Although significant improvement was observed in the mean PC(20) values (from 4.97 +/- 5.24 to 7.47 +/- 6.96 mg/mL; p = 0.0006), BHR was completely eliminated in only one patient.
Conclusions: Our data shows that BHR is fairly common among patients with MS, and severity of bronchial responsiveness is significantly correlated with the severity of MS. Moreover, PMBV leads to significant reduction in pulmonary congestion and a consequent improvement in BHR.