Impact of high transvalvular velocities early after implantation of Freestyle stentless aortic bioprosthesis.

BACKGROUND AND AIM OF THE STUDY: Stentless aortic bioprostheses have excellent hemodynamics, although heterogeneity in gradients has been observed. The present study was intended to determine whether high early postoperative transvalvular velocities correlate with other measures of left ventricular outflow obstruction, whether the phenomenon is transient, and whether high velocities observed early after surgery predict differences in subsequent valve performance or left ventricular remodeling. METHODS: Sixty-eight consecutive patients who underwent implantation of Freestyle stentless aortic bioprosthesis and survived to hospital discharge underwent early postoperative echocardiography. Peak transvalvular velocity was used to define a 'high-velocity' group, based on mean (+ 1 SD) for the group. Mean pressure gradient, ratio of peak to proximal velocities, and effective orifice area were assessed; change in peak velocity and evidence of left ventricular mass regression were studied at one-year follow up. RESULTS: Of 68 patients, 14 (21%) had 'high velocities' based on early postoperative peak transvalvular velocity >3.0 m/s. There was a higher prevalence of women (64% versus 33%, p = 0.04), and both body surface area (1.79+/-0.17 versus 1.95+/-0.20 m2, p = 0.01) and implanted valve size (22.9+/-2.0 versus 24.9+/-2.1 mm, p = 0.003) were smaller among the 'high-velocity' group. High velocity correlated with other measures of resistance to left ventricular outflow, including higher mean gradient (20.9+/-6.5 versus 8.3 +/-4.2 mmHg, p <0.001) and lower effective orifice area (1.15+/-0.36 versus 1.69+/-0.62 cm2, p <0.001). High early postoperative velocities persisted at one year in eight of 13 (62%) patients. Left ventricular mass regression occurred less often in the 'high-velocity' group (38% versus 77% of patients, p = 0.03) and was present in only one of eight (12%) patients in whom high velocity persisted at one year. CONCLUSION: High early postoperative transvalvular velocity suggests resistance to left ventricular outflow. High velocities are transient in some patients, although persistence of high transvalvular velocity suggests 'prosthesis-patient mismatch' with incomplete relief of left ventricular outflow obstruction.

Impact of intraoperative post-pump aortic regurgitation with stentless aortic bioprostheses.

Stentless aortic bioprosthesis performance may be affected by geometric distortion, and intraoperative echocardiography typically is used to assess prosthetic valve function. The impact of minimal or mild post-pump aortic regurgitation has not been previously investigated. Intraoperative post-pump transesophageal echocardiograms and follow-up transthoracic echocardiograms (up to 3 years' postoperatively) were reviewed for 96 patients who underwent implantation of Freestyle (Medtronic) stentless aortic bioprostheses. Minimal or mild aortic regurgitation was present post-pump in 50 of 96 (52%) patients. On early follow-up examination (n = 80), no patient had more than mild aortic regurgitation. Aortic regurgitation had completely resolved in 24 of 39 (62%) patients with post-pump aortic regurgitation, including 15 of 19 (79%) patients with minimal paravalvular regurgitation. The incidence of mild aortic regurgitation at 2 and 3 years did not appear different between patients with and those without post-pump aortic regurgitation. Minimal or mild aortic regurgitation is common on intraoperative post-pump transesophageal echocardiography immediately after implantation of stentless aortic bioprostheses. Resolution is common, especially of small paravalvular jets. Minimal or mild post-pump aortic regurgitation infrequently results in even mild aortic regurgitation on early follow-up evaluation and does not appear to predict clinically significant progression of aortic regurgitation on long-term follow-up evaluation.

The role of echocardiography and CT in the diagnosis of cardiac tumors.

A young male who presented with atypical chest pain was found to have a primary cardiac tumor. Chest X-ray, electrocardiogram, and echocardiographic findings can be nonspecific. Differential diagnosis and the role of different diagnostic modalities including echocardiogram, computerized tomography and magnetic resonance imaging are discussed.

Mitral valve prolapse. Echocardiographic changes during pregnancy.

Mitral valve prolapse (MVP) has been reported to be the most common cardiac disorder in reproductive-age women. The purposes of this prospective investigation were to determine the effect of pregnancy on cardiac function in women thought to have MVP and to determine whether any such changes would adversely affect pregnancy outcome. During a recent three-year period, 43 (1.2%) of 3,582 pregnant women followed in our clinic had a prior diagnosis of MVP without any other cardiac disorder. On closer evaluation, only 21 women (0.6%) had a previous echocardiogram suggestive of MVP. Serial echocardiograms in these women revealed that pregnancy caused either no change or an improvement in the valve prolapse. No cardiac complications were present, and perinatal outcomes were favorable. MVP may be less pronounced during pregnancy, and an echocardiogram late in gestation seems worthwhile to confirm the diagnosis before delivery.

Prognostic significance of vegetations detected by two-dimensional echocardiography in infective endocarditis.

Although 2DE is considered the most sensitive method for detecting vegetations in infective endocarditis, the independent clinical significance of these vegetations continues to be debated. To further examine this, we identified 74 patients who were diagnosed as having infective endocarditis over a 54-month period. The 50 patients who underwent 2DE examination form the basis of this report. Definite vegetations were present in 21 (42%) patients and measured 1.2 +/- 0.2 cm2. The vegetation was localized to the aortic valve in 10 patients, the mitral valve in eight, and the tricuspid valve in three. A major complication, defined as death, new-onset congestive heart failure, major arterial embolus, or valve surgery occurred in 86% of the vegetative endocarditis patients compared to 62% of those without vegetations. Among those patients with vegetations, death occurred in 24%, heart failure in 38%, arterial embolus in 48%, and surgery in 43%. This compared to 7%, 21%, 21%, and 24%, respectively, in those patients without vegetations. These data support the concept that 2DE detection of a vegetation defines a high-risk subgroup of patients with infective endocarditis in whom careful monitoring and aggressive management are warranted.

Assessment of dysfunction in aortic regurgitation by stress-shortening relationship.

Some patients with aortic regurgitation develop irreversible left ventricular dysfunction. The purpose of this study was to noninvasively examine left ventricular function in patients with aortic regurgitation by determining the end-systolic stress-shortening relationship using M-mode echocardiography. Ten normal volunteers and 10 patients with chronic, isolated aortic regurgitation were studied at rest and following load and inotropic alteration by cold pressor testing. The baseline ejection phase indices of ejection fraction and percent fractional shortening did not distinguish between normals and patients with aortic regurgitation (74.6% +/- 2.8% versus 67.0% +/- 4.2%, P = NS and 37.6% +/- 2.4% versus 31.6% +/- 2.7%, P = NS, respectively.) End-systolic stress was significantly greater in patients with aortic regurgitation both at rest (107.8 +/- 11.6 dynes/cm2 X 10(-3) versus 68.4 +/- 4.8 dynes/cm2 X 10(-3), P less than 0.005) and after cold pressor intervention (122.8 +/- 13.0 dynes/cm2 X 10(-3) versus 80.1 +/- 4.0 dynes/cm2 X 10(-3), P less than 0.005). Normals showed increased fractional shortening in the presence of increasing end-systolic stress. Patients with aortic regurgitation showed decreased fractional shortening during increased stress. This response suggests either left ventricular dysfunction with increasing stress or decreased myocardial contractile reserve after cold pressor inotropic stimulation. End-systolic stress-percent fractional shortening relationship may be a sensitive indicator of early left ventricular dysfunction in patients with aortic regurgitation.