Fifty-one patients with normofunctioning aortic prosthetic heart valves were evaluated by Doppler-Echocardiography to determine type-related flow characteristics. The four mechanical valves tested were: Starr-Edwards (1200-1260 aortic), Bjork-Shiley (60 degrees-60 degrees cc aortic), Medtronic-Hall (aortic) and St. Jude Medical (aortic). The most significant dynamic indexes were calculated: Peak (PG) and Mean (MG) Gradient across the valve, Cardiac Index (CI) or Cardiac Output (CO), Regurgitant Jets, Effective Orifice Area (EOA), Spectral Diagram Systolic Trend (SDST) and PVRT (time required to reach peak velocity during systole)/LVET (left ventricular ejection time) Ratio. Patients with Doppler assessed prosthetic dysfunction were dropped out of the study group. As expected, significant reverse correlation (-0.70) was found when transvalvular pressure gradients were compared with valve size. Significant direct correlation (0.82) was found when EOA was compared with valve size, thus suggesting the high reliability of the continuity equation in the assessment of the real orifice area. The Starr-Edwards valve, when compared with the other prostheses of the same size, showed the highest calculated transvalvular gradient; the St. Jude Medical showed the lowest. On the other hand, the Starr-Edwards valve was not commonly associated with regurgitation, while the St. Jude valve was usually moderately incompetent. Those hemodynamic differences should guide the selection of the ideal prosthetic valve for elective surgical indications. Doppler measurements provided noninvasive information similar to that given by cardiac catheterisation, which was reproducible and specific for valve function. According to this high sensitivity and specificity and to the absolute innocuity of the procedure, Doppler-Echocardiography should be considered the elective technique for long-term follow-up in patients with aortic prosthetic heart valves.
Adolescent Adult