[Hemodynamic performance of mechanical aortic valves in narrow aortic annulus cases]. / Küçük aortik annuluslu olgularda mekanik aort kapaklarinin hemodinamik performansi.

OBJECTIVE: Small-sized prosthetic valves used in aortic valve position usually cause a high transvalvular gradient. This situation, especially in people with a high body surface area, causes a patient-prosthetic valve mismatch. In this study, hemodynamic performances of the two new generation bileaflet, small size mechanical valves were evaluated during rest and stress conditions. METHODS: Eighteen patients with implanted 21-mm St. Jude HP (11 cases) and Sorin Bicarbon (7 cases) prosthetic valves in aortic position were evaluated at rest and during dobutamine infusion, 16.3+/-5.5 months after the operation. Dobutamine infusion was started at a dose of 5 microg/kg/min. The infusion rate was increased every 15 minutes up to 10-20-30 microg/kg/min. Maximum gradient, mean gradient, effective valve area (EVA), effective valve area index (EVAI) and performance index (PI) were calculated during rest and maximum dobutamine infusion rate. RESULTS: When the rest and dobutamine infusion measurements were compared, the maximum and mean gradients were found to be increased moderately, but EVA, EVAI, PI values did not change with increasing heart rates. For St. Jude valve; maximum gradient increased from 30.5+/-6.5 mmHg to 74.7+/-33.6 mmHg (p=0.03) and mean gradient increased from 17.9+/-3.8 to 40.8+/-23.8 mmHg (p=0.03). For Sorin Bicarbon valve; maximum gradient increased from 31.7+/-13.3 mmHg to 52.0+/-11.2 mmHg (p=0.01), mean gradient increased from 16.1+/-6.4 mmHg to 28.8+/-1.0 mmHg (p=0.01). The difference was not significant between the two valves with respect to measured parameters during rest and maximum dobutamine infusion. CONCLUSION: According to our findings, 21-mm Sorin Bicarbon and St. Jude HP mechanical bileaflet valves have good hemodynamic performance during exercise and these types of valves seem to be appropriate for patients with small aortic annulus.

Echocardiographic predictors of hemodynamic response and significance of dyspnea development in patients with mitral stenosis during dobutamine stress echocardiography.

BACKGROUND AND AIM OF THE STUDY: In mitral stenosis (MS) patients, resting hemodynamic data do not always correlate with symptom severity. Stress tests may be carried out in these patients, but the mechanisms of different hemodynamic and clinical responses to stress are not clearly established. The study aim was to evaluate hemodynamic changes that correlate with dyspnea development during dobutamine infusion (DI) in patients with MS, and to assess determinants of transmitral gradient response. METHODS: Forty-five consecutive mild or moderately symptomatic patients (36 women, nine men; mean age 44 +/- 10 years; range: 26-66 years), in NYHA class II and with MS (mean mitral valve area (MVA) 1.6 +/- 0.1 cm2; range: 1.5-1.9 cm2) were evaluated with dobutamine stress echocardiography. RESULTS: During DI, dyspnea developed in 12 patients, and 33 patients remained asymptomatic. During infusion, both mean transmitral gradient (6 +/- 3 versus 11 +/- 6 mmHg, p = 0.01) and pulmonary artery systolic pressure (PASP) (13 +/- 4 versus 21 +/- 3 mmHg, p < 0.001) were significantly increased in patients who developed dyspnea compared to others. Hence, a subgroup of patients with more serious MS was identified using the hemodynamic response to dobutamine. Based on these clinical and hemodynamic results, management was changed in 12 patients (27%); five underwent percutaneous mitral balloon commissurotomy and seven received intensive medical treatment. In all patients, PASP at rest (p = 0.001), MVA (p < 0.0001) and subvalvular mitral score (p = 0.004), which is indicative of mitral valve damage, were significantly correlated with mean mitral valve gradient response. CONCLUSION: These results suggest that patients in whom dyspnea is provoked during DI show a greater increase in hemodynamic parameters than patients in whom provocation does not occur. The mean mitral valve gradient-response correlates with baseline pulmonary artery pressure, MVA and subvalvular echo score, and may be predicted by these parameters. Association between dyspnea and presence of severe mitral valve hemodynamics showed a high sensitivity and negative and positive predictive value. It is possible that dyspnea may be of value in identifying those patients with significant mitral valve obstruction.