Maria-Benedicta Edwards

Aortic valve replacement in patients 80 years of age and older: survival and cause of death based on 1100 cases: collective results from the UK Heart Valve Registry.

BACKGROUND Aging of the population and advances in preoperative and postoperative care are reflected in an increasing number of patients > or = 80 years of age undergoing aortic valve replacement (AVR) in the United Kingdom. The present study presents data on postoperative 30-day mortality, actuarial survival, and cause of death based on a large collective patient population. METHODS AND RESULTS Data were extracted from the UK Heart Valve Registry. From January 1986 to December 1995, 1100 patients > or = 80 years of age underwent AVR and were reported to the registry. Six hundred eleven patients (55.5%) were women. The mean follow-up time was 38.9 months. The 30-day mortality was 6.6%. Of the 73 early deaths, 42 were due to cardiac reasons. The actuarial survival was 89%, 79.3%, 68.7%, and 45.8% at 1, 3, 5, and 8 years, respectively. After the first 30 postoperative days, 144 of the 205 deaths were due to noncardiac reasons. Malignancy, stroke, and pneumonia were the most common causes of late death. Bioprosthetic valves were implanted in 969 patients (88%) and mechanical valves in 131 (12%) patients. There was no difference in early mortality and actuarial survival between the two groups (P>.05). CONCLUSIONS The above results suggest that under the selection criteria for AVR currently applied in the United Kingdom, patients > or = 80 years of age show a satisfactory early postoperative outcome and moderate medium-term survival benefit.

Outcomes in nonagenarians after heart valve replacement operation

BACKGROUND Changes in the age profile of the United Kingdom population and improvements in preoperative and postoperative care have resulted in increasing numbers of very elderly patients undergoing heart valve replacement (HVR) operations. Although HVR operations in nonagenarians are relatively uncommon, the demand for cardiac operations in this age group may increase over time. Outcomes after HVR operations in nonagenarians have not been well described yet. Therefore, the aim of this study was to determine outcomes in terms of early mortality and long-term survival in 35 nonagenarians after HVR operation. METHODS Data from the United Kingdom Heart Valve Registry were analyzed and nonagenarian patients were identified. Additional analyzed data include gender, valve position, valve type, valve size, operative priority, follow-up time, and date and cause of death. Kaplan-Meier actuarial curves were calculated to determine accurate 30-day mortality and long-term survival. RESULTS On average five HVR operations are performed annually in the United Kingdom in nonagenarians with equal numbers of males and females. Aortic valve replacement with a bioprosthetic valve was the most common operation and 86% were elective admissions. Fourteen patients died within the review period; mean time to death was 402 days. Overall 30-day mortality was 17%, which was higher for males compared with females; females also displayed better long-term survival. CONCLUSIONS HVR operations in nonagenarians carry a significantly higher risk of early mortality and reduced long-term survival. Despite increases in the age profile of the population, elective HVR operation with patients aged 90 years or older is likely to remain an infrequent surgical procedure reserved for very carefully selected patients.

Thirty-day mortality and long-term survival following surgery for prosthetic endocarditis: a study from the UK heart valve registry

OBJECTIVE To assess the 30-day mortality, long-term survival and freedom from reoperation following surgery for prosthetic endocarditis (PVE). METHOD A retrospective analysis of data from the UK Heart Valve Registry of 322 patients who had undergone single mechanical/bioprosthetic valve replacement for PVE between 1 January 1986 and 31 December 1996. The mean age was 54.9 +/- 12.8 years and 213 (66.1%) were males. There were 170 aortic and 152 mitral valve implantations. Eighty-five (26%) of the infected valves were bioprosthetic and 237 (74%) were mechanical. Of the new prostheses implanted 53 (17%) were bioprosthetic and 269 (83%) were mechanical. Of those with infected bioprostheses, 50 (15.2%) had mechanical valves at redo surgery, whilst 219 (68.3%) of infected mechanical prostheses were re-replaced by mechanical prostheses. The follow-up was 98% complete with a total of 1084.9 patient years. RESULTS The 30-day mortality was 63 (19.9%; 95%CI 15.9-24.7%). There were 85 late deaths. One, 5 and 10 year survival rates were 67.1% (61.6-72.0%), 55.0% (49.0-60.7%) and 37.6% (27.9-47.2%), respectively. Age was the only significant determinant of 30-day mortality (P = 0.04). Age (P = 0.001) and explanting of infected bioprosthesis and replacement by mechanical valve (P = 0.04) determined long-term survival (P = 0.001). The incidence of re-reoperation was 9.9%. Freedom from reoperation for PVE was 88.4, 87.3 and 87.3% at 1, 5 and 10 years, respectively. Explanting of bioprosthesis and replacement by mechanical valve (P < 0.001) and reoperation within 60 days of native valve replacement (P = 0.02) were determinants of reoperation for PVE. Freedom from death or reoperation was 61.1, 50.6 and 34.2% at 1, 5 and 10 years, respectively. Age (P = 0.003), explanting of bioprosthesis and replacement by mechanical valve (P = 0.002) and the period between prosthetic re-replacement (P = 0.04) determined freedom from death or reoperation. CONCLUSION Operation for PVE carries a high 30-day mortality and reduced long-term survival. There is no evidence that type of prosthesis used for re-reoperation determines survival or freedom from re-reoperation.

Prosthetic heart valves: evaluation of magnetic field interactions, heating, and artifacts at 1.5 T.

The purpose of this study was to use ex vivo testing techniques to determine the magnetic resonance imaging (MRI) safety aspects for 32 different heart valve prostheses that had not been evaluated previously in association with the 1.5‐T MR environment. Ex vivo testing was performed using previously described techniques for the evaluation of magnetic field interactions (deflection angle and torque), heating [gel‐filled phantom and fluoroptic thermometry; 15 minutes of MRI at a specific absorption rate (SAR) of 1.1 W/kg], and artifacts (using gradient echo and T1‐weighted spin‐echo pulse sequences). Thirteen heart valve prostheses displayed interactions with the magnetic field. However, these magnetic field interactions were considered relatively minor. Heating was ≤0.8°C for these implants. Artifacts varied from mild to severe depending on the amount and type of metal used to make the particular heart valve prosthesis. For these 32 different heart valve prostheses, the relative lack of substantial magnetic field interactions and negligible heating indicate that MR procedures may be conducted safely in individuals with these implants using MR systems with static magnetic fields of 1.5 T or less. J. Magn. Reson. Imaging 2000;12:363–369.

Mechanical Testing of Human Cardiac Tissue: Some Implications for MRI Safety

PURPOSE The effects of aging on tissue strength and its ability to withstand forces associated with MRI have not been investigated. This study aimed to determine the forces required to cause partial or total detachment of a heart valve prosthesis in patients with age-related degenerative diseases exposed to MRI. METHODS Eighteen tissue samples excised during routine heart valve replacement surgery were subjected to a suture pull-out test using a tensile materials testing machine. Five preconditioning cycles were applied before commencing the final destructive test. The test was complete when the sample ruptured and the suture was pulled completely free from the tissue. Results were compared with previously calculated magnetically induced forces at 4.7 T. RESULTS All tissue samples displayed a basic failure pattern. Mean forces required to cause initial yield and total rupture were 4.0 N (+/- 3.3 N) and 4.9 N (+/- 3.6 N), respectively. Significant factors determining initial yield were stenosed calcific tissue (p < .01), calcific degeneration (single pathology) (p < .04) and tissue stiffness (p < .01). Calcific degeneration (p < .03) and tissue stiffness (p < .03) were also significant in determining maximum force required to cause total rupture. CONCLUSION Specific age-related degenerative cardiac diseases stiffen and strengthen tissue resulting in significant forces being required to pull a suture through valve annulus tissue. These forces are significantly greater than magnetically induced < 4.7 T. Therefore, patients with degenerative valvular diseases are unlikely to be at risk of valve dehiscence during exposure to static magnetic field < or = 4.7 T.

Is 30-Day Mortality an Adequate Outcome Statistic for Patients Considering Heart Valve Replacement?

BACKGROUND In-hospital mortality is widely used by clinicians as a benchmark measure of outcome for determining risks/benefits of cardiac surgery. Patients, however, may wish to have information on estimated longer-term outcomes. Mortality risk by 1 year after the operation may be a more meaningful outcome statistic. We therefore undertook to determine 30-day and 365-day postoperative mortality rates in a large series of consecutive patients who have undergone heart valve replacement (HVR) surgery in the United Kingdom since 1986. METHODS Data on 80,757 patients registered on the UK Heart Valve Registry were analyzed. Kaplan-Meier actuarial survival analysis was calculated to determine 30-day (group 1) and 365-day (group 2) mortality. Cox proportional hazards were calculated for each group to identify significant risk factors for mortality less than 1 year. RESULTS Thirty-day mortality represents around half (56%) of the 365-day mortality. This ratio was robust for most subdivisions of the total population. Cox proportional hazards demonstrated female sex, age older than 70 years, single tricuspid valve replacement, multiple valve replacement regardless of type of valve, and subsequent valve operation as significant risk factors of early mortality (group 1). However, men were at significantly greater risk of late mortality (group 2). All other factors remained significant with the exception of subsequent valve operation, which was dropped from the model (group 2). CONCLUSIONS The robustness of these data would allow cardiologists and cardiac surgeons to provide preoperative patients with a reasonably accurate estimate of survival rates at 1 year after valve replacement surgery in addition to the customary short-term 30-day outcome.

First Redo Heart Valve Replacement A 10-Year Analysis

BACKGROUND The United Kingdom Heart Valve Registry (UKHVR) has recently completed collecting information on 52 659 heart valve replacements (in 47 718 patients) performed during the period 1986 to 1995 in the whole of the United Kingdom. Information stored in the UKHVRs computer database was used for this study. Factors affecting the time from first prosthesis to first redo prosthesis were analyzed and provided useful predictive information. The association between prosthesis-induced local pathological processes and redo valve size was investigated. METHODS AND RESULTS This is a retrospective study of 43 301 patients (from among 47 718 in the database) undergoing single-site replacement of a diseased native mitral or aortic valve over a 10-year period from January 1986 to December 1995 in the United Kingdom. Of these patients, 1051 (2.43%) went on to have a first redo heart valve replacement. Valve survival analysis (Cox regression and Kaplan-Meier curves) was used to study the natural progression to the first redo heart valve replacement. Female sex and having a replacement at the aortic rather than the mitral position were both associated with a longer interval to the first redo operation. Regression analysis showed the size of the redo valve to be influenced by the interoperative time. This effect was more pronounced at the mitral position. CONCLUSIONS Females and patients having an aortic valve replacement exhibit a longer interval to the first redo operation than do males and patients having mitral valve replacements, respectively. The time from the first replacement to the first redo operation significantly affects the size of the first redo valve.

Survival and cause of death after mitral valve replacement in patients aged 80 years and over: collective results from the UK heart valve registry.

OBJECTIVE Over the last decade there has been an increasing number of patients aged 80 years and over undergoing heart valve replacement. However, literature on the outcome of mitral valve replacement (MVR) in this age group is still limited. METHODS We conducted the present study by analysing data extracted from the UK Heart Valve Registry. From January 1986 to December 1994, 86 patients underwent isolated MVR and 10 underwent combined MVR with aortic valve replacement (AVR) and were reported to the Registry. RESULTS The 30 day mortality was 10.4% (9/86) in the MVR group and 10% (1/10) in the MVR and AVR group. The actuarial survival was 79.8, 64.1 and 40.7% at 1, 3 and 5 years, respectively, in the MVR group. Of the 10 early (30 day) deaths, 8 were due to cardiac reasons and 19 of the 28 late deaths were due to non-cardiac reasons. A total of 55 (57.2%) patients received a bioprosthetic valve implant and 41 (42.8%) patients received a mechanical valve implant. There was no difference in survival between the two groups. CONCLUSIONS The above results suggest that MVR in octogenarians produces a satisfactory early postoperative outcome and moderate medium-term benefit. There is no difference in survival between patients receiving bioprosthetic and patients receiving mechanical valve implants.

Composite Aortic Valve Graft Replacement Mortality Outcomes in a National Registry

Background— Composite aortic valve and root replacement (CVG) is a complex surgical procedure, but excellent center-specific outcomes are reported. We sought to report outcomes in a national cohort. Methods and Results— The United Kingdom Heart Valve Registry was interrogated for 1962 first-time CVG (and 37 102 aortic valve replacements [AVR] as a reference group) procedures from 1986 to 2004. We analyzed 30-day mortality, long-term survival (97.2% complete follow-up), and examined available risk factors for mortality using univariate and multivariate logistic regression analysis and causes of death. CVG patients were younger, received larger valve sizes and were more likely to be emergent than AVR patients. Overall 30-day mortality was 10.7% (CVG) and 3.6% (AVR). For CVG, multivariate analysis identified advanced age (>70 years), concomitant coronary artery surgery, impaired left ventricular function, urgent or emergency status, prosthetic valve size ≤23 mm and hospital activity volume ≤8 procedures per annum as significant factors for 30-day mortality. Kaplan-Meier, 1-year, 5-year, 10-year and 20-year survival were 85.2%, 77.1%, 70% and 59.3%, respectively. The conditional (post–30-day) survival was similar to the AVR cohort. Conclusions— These Registry data provide a unique national insight into CVG outcomes. After a higher initial mortality risk, CVG has equivalent conditional longer-term survival to AVR.

Assessment of magnetic field (4.7 T) induced forces on prosthetic heart valves and annuloplasty rings

To assess the magnetic field interactions on 11 heart valve prostheses and 12 annuloplasty rings subjected to a 4.7 T MR system.