Animal experimental implantation of an atrial septal defect occluder system. (1/2034)

OBJECTIVE: To establish the implantation technique for the atrial septal defect occluder system (ASDOS) device in an experimental animal model and to determine long term mechanical stability of the device and its in vivo properties in terms of biocompatibility and tissue reaction. MATERIALS AND METHODS: An atrial septal defect was created and the device implanted in 17 pigs (mean weight 30 kg). The implantation technique was refined and modified because of initial technical and anatomical complications during nine acute pilot studies. The technique proved to be feasible in eight subsequent survival studies. Four pigs were electively killed three months after implantation (group 1). The remaining four pigs were killed six months after implantation (group 2). RESULTS: Necropsy showed all devices were embedded in soft tissue three months after implantation. Microscopic examination of atrial septal tissue showed an acute granulomatous inflammatory reaction in group 1 and fibrosis in group 2. The intensity of the inflammatory reaction around the device was clearly milder in group 2, indicating a decline in the inflammatory response with time. Clinical and biochemical investigations indicated acceptable biocompatibility of the device. CONCLUSION: The implantation technique for the ASDOS device in a chronic pig model has been established. Biocompatibility of the device was acceptable.  (+info)

Bileaflet mechanical prostheses for aortic valve replacement in patients younger than 65 years and 65 years of age or older: major thromboembolic and hemorrhagic complications. (2/2034)

OBJECTIVE: To determine major thromboembolic and hemorrhagic complications and predictive risk factors associated with aortic valve replacement (AVR), using bileaflet mechanical prostheses (CarboMedics and St. Jude Medical). DESIGN: A case series. SETTING: Cardiac surgical services at the teaching institutions of the University of British Columbia. PATIENTS AND METHODS: Patients 2 age groups who had undergone AVR between 1989 and 1994 were studied. Group 1 comprised 384 patients younger than 65 years. Group 2 comprised 215 patients 65 years of age and older. RESULTS: The linearized rates of major thromboembolism (TE) occurring after AVR were 1.54%/patient-year for group 1 and 3.32%/patient-year for group 2; the rates for major TE occurring more than 30 days after AVR were 1.13%/patient-year for group 1 and 1.55%/patient-year for group 2. The crude rates for major TE occurring within 30 days of AVR were 1.04% for group 1 and 3.72% for group 2. The death rate from major TE in group 1 was 0.31%/patient-year and in group 2 was 0.88%/patient-year. Of the major TE events occurring within 30 days, 100% of patients in both age groups were inadequately anticoagulated at the time of the event, and for events occurring more than 30 days after AVR, 45% in group 1 and 57% in group 2 were inadequately anticoagulated (INR less than 2.0). The overall linearized rates of major hemorrhage were 1.54%/patient-year for group 1 and 2.21%/patient-year for group 2. There were no cases of prosthesis thrombosis in either group. The mean (and standard error) overall freedom from major TE for group 1 patients at 5 years was 95.6% (1.4%) and with exclusion of early events was 96.7% (1.3%); for group 2 patients the rates were 90.0% (3.2%) and 93.7% (3.0%), respectively. The mean (and SE) overall freedom from major and fatal TE and hemorrhage for group 1 patients was 90.1% (2.3%) and with exclusion of early events was 91.2% (2.3%); for group 2 patients the rates were 87.9% (3.1%) and 92.5% (2.9%), respectively. The 5-year rate for freedom from valve-related death for group 1 patients was 96.3% (2.1%) and for group 2 patients was 97.2% (1.2%). CONCLUSION: The thromboembolic and hemorrhagic complications after AVR with bileaflet mechanical prostheses occur more frequently and result in more deaths in patients 65 years of age and older than in patients years younger than 65 years.  (+info)

Minimally invasive aortic valve replacement through a transverse sternotomy: a word of caution. (3/2034)

OBJECTIVES: To compare aortic valve replacement (AVR) using a minimally invasive approach through a transverse sternotomy with the established approach of median sternotomy. DESIGN: Retrospective, case-control study. PATIENTS: Fourteen high risk patients (median age 78, Parsonnet score of 18%) who underwent AVR performed through a minimally invasive transverse sternotomy were compared with a historical group of patients matched for age, sex, and Parsonnet score who underwent AVR performed through a median sternotomy by the same surgeon. OUTCOME MEASURES: Cross clamp time, total bypass time, intensive care stay, postoperative in-hospital stay, morbidity, and mortality. RESULTS: There were two deaths in the minimally invasive group and none in the control group (NS). The cross clamp and total bypass times were longer in the minimally invasive group (67 and 92 minutes v 46 and 66 minutes, p < 0.001). There was a higher incidence of re-exploration for bleeding (14% v 0%) and paravalvar leaks (21% v 0%) in the minimally invasive group but these differences were not significant. The minimally invasive group had a longer postoperative in-hospital stay (p = 0.025). The incidence of mortality or major morbidity was 43% (six of 14) in the minimally invasive group and 7% (one of 14) in the matched pairs (p = 0.013). CONCLUSIONS: AVR can be performed through a transverse sternotomy but the operation takes longer and there is an unacceptably high incidence of morbidity and mortality.  (+info)

Perivalvular abscesses associated with endocarditis; clinical features and prognostic factors of overall survival in a series of 233 cases. Perivalvular Abscesses French Multicentre Study. (4/2034)

AIMS: The purposes of this study were to determine the clinical features and to identify prognostic factors of abscesses associated with infective endocarditis. METHODS AND RESULTS: During a 5-year period from January 1989, 233 patients with perivalvular abscesses associated with infective endocarditis were enrolled in a retrospective multicentre study. Of the patients, 213 received medical surgical therapy and 20 medical therapy alone. No causative microorganism could be identified in 31% of cases. Sensitivity for the detection of abscesses was 36 and 80%, respectively using transthoracic and transoesophageal echocardiography. Surgical treatment consisted of primary suture of the abscess (38%), insertion of a felt aortic or mitral ring using Teflon or pericardium (42%), or debridment of the abscess cavity (20%). The 1 month operative mortality was 16%. Actuarial rates for overall survival at 3 and 27 months in operated patients were 75 +/- 10% and 59 +/- 11%, respectively. Increasing patient age, staphylococcal infection, and fistulization of the abscess were found to be independent risk factors in both 1 month and overall operative mortality. Renal failure was a risk factor predictive of operative mortality at 1 month, whereas uncontrolled infection and circumferential abscess were regarded as risk factors predictive of overall operative mortality. CONCLUSION: The data determined prognostic factors of abscesses associated with infective endocarditis.  (+info)

Replacement of the aortic root in patients with Marfan's syndrome. (5/2034)

BACKGROUND: Replacement of the aortic root with a prosthetic graft and valve in patients with Marfan's syndrome may prevent premature death from rupture of an aneurysm or aortic dissection. We reviewed the results of this surgical procedure at 10 experienced surgical centers. METHODS: A total of 675 patients with Marfan's syndrome underwent replacement of the aortic root. Survival and morbidity-free survival curves were calculated, and risk factors were determined from a multivariable regression analysis. RESULTS: The 30-day mortality rate was 1.5 percent among the 455 patients who underwent elective repair, 2.6 percent among the 117 patients who underwent urgent repair (within 7 days after a surgical consultation), and 11.7 percent among the 103 patients who underwent emergency repair (within 24 hours after a surgical consultation). Of the 675 patients, 202 (30 percent) had aortic dissection involving the ascending aorta. Forty-six percent of the 158 adult patients with aortic dissection and a documented aortic diameter had an aneurysm with a diameter of 6.5 cm or less. There were 114 late deaths (more than 30 days after surgery); dissection or rupture of the residual aorta (22 patients) and arrhythmia (21 patients) were the principal causes of late death. The risk of death was greatest within the first 60 days after surgery, then rapidly decreased to a constant level by the end of the first year. CONCLUSIONS: Elective aortic-root replacement has a low operative mortality. In contrast, emergency repair, usually for acute aortic dissection, is associated with a much higher early mortality. Because nearly half the adult patients with aortic dissection had an aortic-root diameter of 6.5 cm or less at the time of operation, it may be prudent to undertake prophylactic repair of aortic aneurysms in patients with Marfan's syndrome when the diameter of the aorta is well below that size.  (+info)

Dose-dependent fetal complications of warfarin in pregnant women with mechanical heart valves. (6/2034)

OBJECTIVES: The purpose of this study was to assess the incidence of warfarin fetal complications and whether they are dose-dependent. BACKGROUND: Gravid patients with mechanical heart valves require long-term anticoagulant therapy. Controversy exists concerning the appropriate treatment of these patients. METHODS: Forty-three women on warfarin carrying out 58 pregnancies were studied. For each patient with full-term pregnancy a caesarian section was scheduled for the 38th week during brief warfarin discontinuation. Maternal and fetal complications were evaluated. Fetal complications were divided according to the warfarin dosage < or = 5 mg and > 5 mg necessary to keep an international normalized ratio (INR) of 2.5 to 3.5, and analyzed subsequently. RESULTS: A total of 58 pregnancies were observed: 31 healthy babies (30 full term, 1 premature) and 27 fetal complications (22 spontaneous abortions, 2 warfarin embryopathies, 1 stillbirth, 1 ventricular septal defect, 1 growth retardation) were recorded. Two maternal valve thromboses occurred. No fetal or maternal bleeding was observed during caesarian sections or premature vaginal delivery. Patients whose warfarin doses during pregnancy were > 5 mg had 22 fetal complications, whereas those taking a dose < or = 5 mg had only five fetal complications (p = 0.0001). For an increase of the warfarin dose there was a substantially increased probability of fetal complications (p < 0.0001; p < 0.7316). CONCLUSIONS: There is a close dependency between warfarin dosage and fetal complications. Patients on warfarin anticoagulation may be delivered by planned caesarian section at the 38th week while briefly interrupting anticoagulation.  (+info)

Acute renal failure following cardiac surgery. (7/2034)

BACKGROUND: Acute renal failure requiring dialysis (ARF-D) occurs in 1.5% of patients following cardiac surgery, and remains a cause of major morbidity and mortality. While some preoperative risk factors have been characterized, the influence of preoperative and intraoperative factors on the occurrence of ARF following cardiac surgery is less well understood. METHODS: Preoperative and intraoperative data on 2843 consecutive adult patients undergoing cardiac surgery with cardiopulmonary bypass (CPB) from February 1, 1995 to February 1, 1997 were recorded and entered into a computerized database. Two definitions of renal failure were employed: (i) ARF defined as a rise in serum creatinine (Cr) of 1 mg/dl above baseline; and (ii) ARF-D defined as the development of ARF for which some form of dialytic therapy was required. The association between preoperative and intraoperative variables and the development of ARF was assessed by multivariate logistic regression. RESULTS: A total of 2672 of the 2844 patients underwent isolated coronary artery bypass grafting (CABG) surgery, the remaining 172 underwent valve surgery with or without bypass grafting. Of the CABG patients 7.9% developed ARF and 0.7% developed ARF-D. The mortality for patients who developed ARF was 14% (OR 15, P = 0.0001) compared with 1% among those who did not develop ARF. The mortality for CABG patients who developed ARF-D was 28% (OR 20, P = 0.0001) compared with 1.8% among those who did not require dialysis. Variables that were significantly associated with the development of ARF by multivariate analysis included: increased age, elevated preoperative serum Cr, duration of CPB, presence of a carotid artery bruit, presence of diabetes, reduced cardiac ejection fraction and increased body weight. Variables independently associated with ARF-D included serum Cr, duration of CPB, carotid artery bruit and presence of diabetes. The utility of these models for predicting the development of ARF and ARF-D was confirmed by bootstrapping techniques. Because of the small number of patients who underwent valve surgery, none of these variables were significantly associated with the development of ARF or ARF-D in this group of patients. CONCLUSION: The development of ARF or ARF-D is associated with a high mortality following CABG surgery. We have identified perioperative variables, which may be useful in stratifying risk for the development of ARF.  (+info)

The natural history of aortic valve disease after mitral valve surgery. (8/2034)

OBJECTIVES: The present study evaluates the long-term course of aortic valve disease and the need for aortic valve surgery in patients with rheumatic mitral valve disease who underwent mitral valve surgery. BACKGROUND: Little is known about the natural history of aortic valve disease in patients undergoing mitral valve surgery for rheumatic mitral valve disease. In addition there is no firm policy regarding the appropriate treatment of mild aortic valve disease while replacing the mitral valve. METHODS: One-hundred thirty-one patients (44 male, 87 female; mean age 61+/-13 yr, range 35 to 89) were followed after mitral valve surgery for a mean period of 13+/-7 years. All patients had rheumatic heart disease. Aortic valve function was assessed preoperatively by cardiac catheterization and during follow-up by transthoracic echocardiography. RESULTS: At the time of mitral valve surgery, 59 patients (45%) had mild aortic valve disease: 7 (5%) aortic stenosis (AS), 58 (44%) aortic regurgitation (AR). At the end of follow-up, 96 patients (73%) had aortic valve disease: 33 AS (mild or moderate except in two cases) and 90 AR (mild or moderate except in one case). Among patients without aortic valve disease at the time of the mitral valve surgery, only three patients developed significant aortic valve disease after 25 years of follow-up procedures. Disease progression was noted in three of the seven patients with AS (2 to severe) and in six of the fifty eight with AR (1 to severe). Fifty two (90%) with mild AR remained stable after a mean follow-up period of 16 years. In only three patients (2%) the aortic valve disease progressed significantly after 9, 17 and 22 years. In only six patients of the entire cohort (5%), aortic valve replacement was needed after a mean period of 21 years (range 15 to 33). In four of them the primary indication for the second surgery was dysfunction of the prosthetic mitral valve. CONCLUSIONS: Our findings indicate that, among patients with rheumatic heart disease, a considerable number of patients have mild aortic valve disease at the time of mitral valve surgery. Yet most do not progress to severe disease, and aortic valve replacement is rarely needed after a long follow-up period. Thus, prophylactic valve replacement is not indicated in these cases.  (+info)