Haemodynamic performance of aortic pericardial bioprostheses and bileaflet prostheses at rest and during exercise: implications for the surgical management of patients with small aortic roots

Abstract

Objective-To determine the haemodynamic behaviour, at rest and during exercise, of aortic valve pericardial bioprostheses and diVerent sizes of bileaflet prosthesis. Design-Observational study. Setting-Tertiary medical centre. Patients and interventions-74 patients (33 women, 41 men; mean age 64 years) in whom 40 pericardial bioprostheses and 34 bileaflet prostheses sized 19, 21, or 23 mm had been implanted to replace aortic valves. Main outcome measures-Doppler echocardiography at rest and at peak exercise, between 12 and 47 months after surgery. Results-All patients achieved a significant increase in heart rate, systolic blood pressure, and cardiac output with exercise. Transvalvar pressure fall, valve area, and left ventricular systolic and diastolic function indices also underwent significant changes with exercise. Reductions in peak and mean transvalvar pressure, at rest and at peak exercise, were greater in patients with small valves (p < 0.05). Valve areas and eVective area index were greater in the patients with larger valves (p < 0.001). There were no significant differences between patients with mechanical and biological prostheses with regard to transvalvar pressure fall and valve areas at rest and at peak exercise. Conclusions-19 mm and 21 mm aortic prostheses and bioprostheses continue to create significant obstruction, particularly with exercise. (Heart 1999;82:149-155)

Surgical Method for Facilitation of Aortic Valve Replacement: Intraoperative Application of External Pressure for Increasing the Transverse Axis of Aortic Annulus

“…Second, because the stented prosthesis has its own annulus, the effective orifice area after the implantation is actually smaller than that of a normal native valve. Factors that may predict PPM preoperatively are as follows: larger body surface area, high body mass index, older age, smaller prosthesis size, and valvular stenosis as the predominant lesion before the operation [11]- [13]. Patient-prosthesis mismatch occurs more frequently in patients with stenotic native valves and in older patients.…”

“…This subsequently provides a clinical recovery and prolongs the life expectancy. In contrary, small prostheses may be threatening in especially early and late periods of life and during exercise by creating an obstruction through the left ventricle outlet [11]- [16]. It was demonstrated that both prosthetic and bioprosthetic valves are narrower than the natural valves, and although function normally, they may lead to some degree of a gradient [17] [18].…”

“…First, patients with aortic valve disease frequently exhibit annulus calcification and fibrosis in addition to the left ventricle hypertrophy, which reduce the size of the aortic annulus [9]- [11]. In these circumstances, prosthesis smaller than calculated with respect to the patient's body surface area-should be implanted.…”

Exercise Hemodynamic and Functional Capacity After Mitral Valve Replacement in Patients With Ischemic Mitral Regurgitation

“…On the contrary, a significant exercise increment of i-EOA was found in the MVRm, challenging the generally assumption which assume, in the aortic mechanical valves, an on/off phenomenon. 31 Many reasons, such as the type of effort or the method used for calculating the valve area, have been advocate, to explain this finding. 31 However, an on/off phenomenon cannot be translated to the mitral prostheses, in which the mechanism of valve opening is a complex interaction between left atrium and LV.…”

“…31 Many reasons, such as the type of effort or the method used for calculating the valve area, have been advocate, to explain this finding. 31 However, an on/off phenomenon cannot be translated to the mitral prostheses, in which the mechanism of valve opening is a complex interaction between left atrium and LV. Hobson et al 16 reported a significant dobutamine stress increase of the EOA.…”