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Biomedical subjects

V Bors

Publications and source records attributed to V Bors.

At least 19 recordsLinked to original sources
PubMed2003

Bridge to transplantation with the Jarvik-7 (CardioWest) total artificial heart: a single-center 15-year experience.

BACKGROUND: At our institution, the total artificial heart (TAH) Jarvik-7 (CardioWest) has been used since 1986 as a bridge to transplantation for the most severely ill patients with terminal congestive heart failure. METHODS: Between 1986 and 2001, 127 patients (108 males, mean age 38 +/- 13) were bridged to transplantation with the Jarvik-7 TAH. All were in terminal biventricular failure despite high-dose inotropic support. Nine patients had a body surface area (BSA) of <1.6 m(2). In Group I patients (78%), the etiology of cardiac failure was dilated cardiomyopathy, either idiopathic (n = 60) or ischemic (n = 38). The other 29 patients (Group II) had disease of miscellaneous origin. We analyzed our experience with regard to 3 time periods: 1986 to 1992 (n = 63); 1993 to 1997 (n = 36); and 1998 to 2001 (n = 33). RESULTS: Although Group II patients represented 30% of indications before 1992, they comprised only 15% during the 2 subsequent periods. Duration of support for transplant patients increased dramatically after 1997, reaching 2 months for the most recent period (5 to 271 days). In Group I, the percentage of transplanted patients increased from 43% before 1993 to 55% between 1993 and 1997, and reached 74% thereafter. The major cause of death was multiorgan failure (67%). The clinical thromboembolic event rate was particularly low with no instance of cerebrovascular accident and 2 transient ischemic attacks. Total bleeding complication rate was 26%, including 2 deaths related to intractable hemorrhage and 2 others related to atrial tamponade. The cumulative experience was 3,606 total implant days with only 1 instance of mechanical dysfunction. CONCLUSIONS: TAH is a safe and efficient bridge for patients with terminal congestive heart failure awaiting cardiac transplantation.

Adolescent↗
PubMed2002

[Fulminating myocarditis: myocardial recovery after circulatory assistance].

The clinical expression of acute myocarditis is variable from paucisymptomatic to fulminating forms which are usually lethal within days. The latter presentation takes the form of very acute cardiac failure. During this phase, the severity of myocardial dysfunction may be such that death ensues. However, if the patient survives, paradoxically, these forms have a better long-term prognosis with complete recovery of myocardial function being possible after the acute phase. The authors report a typical case of fulminating myocarditis with electromechanical dissociation, which recovered completely after a period of circulatory assistance. This case illustrates the rapidity of deterioration of the haemodynamic status and the importance of organ dysfunction despite early management. In a review of the literature, the authors found about 150 reported cases of acute myocarditis treated with circulatory assistance. In the best series, about half the patients were weaned off the circulatory assistance without having to undergo cardiac transplantation. However, the potential recovery of myocardial function is difficult to predict.

Adult↗
PubMed2001

Expanded polytetrafluoroethylene membranes to wrap surfaces of circulatory support devices in patients undergoing bridge to heart transplantation.

OBJECTIVE: Because of a lack of donor hearts, an increasing number of patients with heart failure must now undergo bridge to cardiac transplantation with a mechanical circulatory support device. Moreover, support periods have become longer. As a result, pericardial adhesions may develop while the support device is implanted, increasing the risk of injury at resternotomy and bleeding after transplantation. Use of expanded polytetrafluoroethylene (ePTFE) pericardial substitutes (membranes) may prevent such adhesions. PATIENTS AND METHODS: From January 1997 to December 1999, ePTFE membranes were used in 23 patients to wrap portions of an implanted left ventricular assist device (LVAD) or total artificial heart (TAH). Any complications during mechanical support or at cardiac transplantation were recorded. Six ePTFE membranes removed at transplantation were studied histologically. RESULTS AND CONCLUSIONS: At resternotomy for transplantation, the plane of dissection between tissues, ePTFE membranes, and surfaces of the mechanical support device were easily discerned. No adhesions were observed between tissues and membranes. There were no injuries during resternotomy and no patient had to undergo reoperation because of bleeding. One patient given a TAH had an infection during circulatory support that was controlled by antibiotic therapy. In another patient, clots developed between the device and an ePTFE membrane; these were removed successfully. Histologic studies of removed ePTFE membranes showed no infiltration of the membranes interstices by collagen or cellular components. Use of ePTFE membranes in patients undergoing bridge to transplantation with either an LVAD or a TAH limited adhesions between tissues and device surfaces without increasing the risk of infection.

Adolescent↗
PubMed2000

[End-stage heart failure: role of various circulation assistance techniques].

There are currently 4 main types of cardiac assist devices: centrifugal pumps, paracorporeal pneumatic assist devices, implantable ventricular assist devices, total artificial heart. Although the efficacy of centrifugal pumps remains limited, that of the other 3 types of assist devices has now been clearly demonstrated. The choice between these various devices depends on the severity of heart failure at the time of implantation, the univentricular or biventricular disease, the potential for recovery, the patient's morphology and obviously the device or devices available to the team concerned. The results essentially depend on early implantation.

Chronic Disease↗
PubMed1999

Posttransplantation cytotoxic immunoglobulin G is associated with a high rate of acute allograft dysfunctions in heart transplant recipients.

BACKGROUND: The significance of anti-human leukocyte antigen immunoglobin G (IgG) detected in the posttransplantation course of heart graft recipients remains unclear. METHOD: Sera from 121 cardiac allograft recipients transplanted between January 1992 and December 1994 were screened for the presence of lymphocytotoxic antibodies in the first year after transplantation. Dithiothreitol was used to differentiate IgG from immunoglobulin M. RESULTS: Nineteen patients (15%) had cytotoxic IgG develop, mainly during the first month after transplantation. The percentage of women was higher in this group (42% vs 15.7%; P <.05). Donor to recipient mismatches for sex, blood typing, cytomegalovirus serology, and human leukocyte antigen typing were comparable between IgG producers and nonproducers. The frequency of acute allograft dysfunction during the first year after transplantation was significantly higher among patients producing IgG (42% vs 5.9; P <.001). Most of these acute allograft dysfunctions were independent of cellular rejection lesions but were associated with a thickening of the posterior wall and the interventricular septum during the acute episode. Finally, all the patients but one recovered. Recurrences were not uncommon and, at 1 year after transplantation, the dose of cyclosporine used in patients producing IgG was significantly greater, as was the left ventricular thickness. CONCLUSION: Posttransplantation cytotoxic IgG is not uncommon and appears to be associated with a high rate of acute allograft dysfunction. Development of these antibodies can be caused by a previous undetected immunization, as suggested by the higher percentage of women in the producer group. Correlation with histologic lesions of humoral rejection are discussed.

Adolescent↗
PubMed1998

Pacemaker infective endocarditis.

We identified 33 patients with definite pacemaker endocarditis--that is, with direct evidence of infective endocarditis, based on surgery or autopsy histologic findings of or bacteriologic findings (Gram stain or culture) of valvular vegetation or electrode-tip wire vegetation. Most of the patients (75%) were > or = 60 years of age (mean 66 +/- 3; range 21 to 86). Pouch hematoma or inflammation was common (58%), but other predisposing factors for endocarditis were rare. At the time that pacemaker endocarditis was found, the mean number of leads was 2.4 +/- 1.1 (range 1 to 7). The interval from the last procedure to diagnosis of endocarditis was 20 +/- 4 months (range 1 to 72). Endocarditis appeared after pacemaker implantation, early (< 3 months) in 10 patients and late (> or = 3 months) in 23 patients. Fever was the most common symptom, being isolated in 36%, associated with a poor general condition in 24%, and associated with septic shock in 9%. Transthoracic echocardiography showed vegetations in only 2 of 9 patients. Transesophageal echocardiography demonstrated the presence of lead vegetations (n = 20) or tricuspid vegetations (n = 3) in 23 of 24 patients (96%; p <0.0001 compared with transthoracic echocardiography). Pulmonary scintigraphy showed a typical pulmonary embolization in 7 of 17 patients (41%). Pathogens were mainly isolated from blood (82%) and lead (91%) cultures. The major pathogens causing pacemaker endocarditis were Staphylococcus epidermidis (n = 17) and S. aureus (n = 7). S. epidermidis was found more often in early than in late endocarditis (90% vs 50%; p = 0.05). All patients were treated with prolonged antibiotic regimens before and after electrode removal. Electrode removal was achieved by surgery (n = 29) or traction (n = 4). Associated procedures were performed in 9 patients. After the intensive care period, only 17 patients needed a new permanent pacemaker. Overall mortality was 24% after a mean follow-up period of 22 +/- 4 months (range 1 to 88). Eight patients who were significantly older (74 +/- 3 vs 63 +/- 3 years; p = 0.05) died < or = 2 months after electrode removal, whereas 25 were alive and asymptomatic.

Adult↗
PubMed1998

La Pitié heart transplantation: 30-year single center clinical experience.

At La Pitié Hospital, 1,184 patients underwent cardiac transplantation for end-stage cardiac disease (1,122 orthotopic and 62 heterotopic) between April 1968-November 1998. Since April 1986, 140 patients have been supported using several different mechanical assist devices as a bridge to transplantation. Twenty-four retransplantations (2.2%) were performed for primary graft failure in 4 (17%), refractory acute rejection in 7(29%), coronary graft disease in 11 (46%) and others in 2 (8%) patients. In a case-control study, retransplanted patients were matched with first transplant patients and survival rates at one and 5 years were 59.4% and 38.8% compared with survival rates for retransplanted patients of 45.4% and 31.2%, respectively. Seventy-four patients survived more than 10 years (61 males, 13 females). Mortality did not increase after 10 years. Unfortunately many suffered complications: 77% had hypertension, hypercholesterolemia (22%), hyperuricemia (41%), osteoporosis (11%), osteonecrosis (5%) and diabetes (7%). Renal function remains one of the main problems; 16% had a creatinine > 180 mumol/L and patients are on chronic dialysis.

Actuarial Analysis↗
PubMed1998

[The cardiowest total artificial heart: experience of 29 cases].

The authors studied the outcome of multi-organ failure in 29 patients with terminal cardiac failure and maintained with a Cardiotest total artificial heart whilst waiting for cardiac transplantation. Pre-implantation organ dysfunction was defined by the following criteria; assisted respiration of over 3 days, total billirubin and creatinine levels of over 2 mg/dL, a platelet count of less than 80,000/mL or a prothrombin ratio of less than 50% and central nervous system disturbances. Fourteen patients died during the period of circulatory assistance and 71% of deaths were due to multi-organ failure. Pre-implantation plasma total bilirubin levels were significantly higher in patients who died of multi-organ failure (p = 0.04). Eighty per cent of patients who died of multi-organ failure had at least 3 criteria of organ dysfunction before implantation of the artificial heart compared with only 37% in the other patients (p = 0.04). Finally, systemic vascular resistances before implantation were significantly lower in patients who died of multi-organ failure. The results of this study suggest that multi-organ failures does not develop during the period of circulatory assistance but represents an aggravation of a preexisting morbid condition. This observation should lead to a limitation of the indications of total circulatory assistance in some cases and, above all, to earlier intervention before multi-organ failure becomes irreversible.

Adult↗
PubMed1997

Cardiac calcium release channel (ryanodine receptor) in control and cardiomyopathic human hearts: mRNA and protein contents are differentially regulated.

Abnormal intracellular calcium handling in cardiomyopathic human hearts has been associated with an impaired function of the sarcoplasmic reticulum, but previous reports on the gene expression of the ryanodine receptors (Ry2) are contradictory. We measured the mRNA levels, the protein levels and the number of high affinity [3H]ryanodine binding sites in the left ventricle of non-failing (n = 9) and failing human hearts [idiopathic dilated (IDCM n = 16), ischemic (ICM n = 7) or mixed (MCM n = 8) cardiomyopathies]. Ry2 mRNA levels were significantly reduced in IDCM (-30%) and unchanged in MCM and ICM and Ry2 protein levels were similar. In contrast, we observed a two-fold increase in the number of high affinity Ry2 (B(max) = 0.43 +/- 0.11 v 0.22 +/- 0.13 pmol/mg protein, respectively; P<0.01) and an unchanged K(d). Furthermore, levels of myosin heavy chain mRNA and protein per g of tissue were similar in failing and non-failing hearts, suggesting that the observed differences in Ry2 are not caused by the increase in fibrosis in failing heart. Therefore, the dissociation between the two-fold increase in the number of high affinity ryanodine receptors observed in all failing hearts and the slightly decreased mRNA level or unchanged protein level suggests that the ryanodine binding properties are affected in failing myocardium and that such modifications rather than a change in gene expression alter the channel activity and could contribute to abnormalities in intracellular Ca2+ handling.

Adult↗
PubMed1997

Active native valve endocarditis: determinants of operative death and late mortality.

BACKGROUND: In this report, we reviewed 247 patients who underwent operation by our team for active native valve endocarditis between January 1979 and December 1993. METHODS: There were 201 male and 46 female patients (mean age, 45.4 +/- 6 years). The aortic valve was involved in 163 cases, the mitral valve in 36 cases, both mitral and aortic valves in 44 cases, and the tricuspid valve alone in 4 cases. The most common microorganisms were streptococci. Univariate Pearson (chi2 test) and multivariate (stepwise logistic regression [BMDPLR]) analyses were used to identify significant predictors of operative mortality, reoperation, and recurrent endocarditis. Cox proportional hazards regression model was used to study late survival. RESULTS: Operative mortality was 7.6% (n = 19). Increased age, cardiogenic shock at the time of operation, insidious illness, and greater thoracic ratio (>0.5) were the predominant risk factors; the length of antibiotic therapy appeared to have no influence. Two hundred thirteen patients were followed up. Median follow-up time was 6 years (range, 2 to 19 years). Overall survival rate (operative mortality excluded) was 71.3% +/- 3.8% at 9 years. Increased age, preoperative neurologic complications, cardiogenic shock at the time of operation, shorter duration of the illness, insidious illness before the operation, and mitral valve endocarditis were the predominant risk factors for late mortality. The probability of freedom from reoperation (operative mortality included) was 73.3% +/- 4.2% at 8 years; risk factors were younger age and aortic valve endocarditis. The rate of prosthetic valve endocarditis was 7%. No significant risk factor was found. CONCLUSIONS: Increased age, insidious illness, and hemodynamic failure are the main risk factors for operative mortality. Long-term survival is good except for patients with preoperative neurologic complications and mitral valve endocarditis.

Adult↗
PubMed1997

[Video-assisted coronary artery bypass].

The benefits of the internal mammary artery (IMA), as a graft, particularly for the left anterior descending (LAD) coronary artery disease, have been demonstrated. Coronary artery bypass grafting (CABG) without cardiopulmonary bypass (CPB) is now an accepted technique of myocardial revascularization. Thoracoscopy and a minimal thoracotomy have been applied to cardiac surgery, however its use has not been well defined; in our approach, we harvested the left IMA thoracoscopically. Following this the left IMA-LAD coronary artery anastomosis was fashioned, by means of a left small anterior thoracotomy on the beating heart without CPB. A double lumen endotracheal tube was used so the lung could be collapsed. Three left lateral chest ports of 1 cm were made, and the thoracoscope was placed through the initial port, permitting inspection of the thorax. The other ports were used for IMA dissection, using endoscopic instruments (electrocautery, grasping, forceps,...), the side branches were controlled by either cautery or endoscopic clips. When it was possible, the anterior port was extended doing a small left anterior thoracotomy, the pericardium was exposed, the IMA was divided and exteriorized through the thoracotomy. After coronary artery control, the bypass graft was carried out on the beating heart without CPB, in 26 patients. From september 1995 to july 1996, we have operated on 30 patients using this technique. We believe that with increasing operator experience, this minimally invasive approach will have a major impact on the management of the coronary artery disease patients, with a faster recovery, shorter hospitalization, and certainly less cost.

Adult↗
PubMed1997

Position-related factors in mitral and tricuspid bioprostheses degenerative changes.

We report clinicopathological findings in 15 patients in whom the same bioprosthesis (BP) had been implanted simultaneously in both mitral and tricuspid positions. The aim of the study was to investigate whether position-related factors played an important role in BP degeneration. There were 14 women and 1 man with a mean age of 34 +/- 11 years. The indications for the initial operation were rheumatic in 14 cases and endocarditis in one patient. The mean interval before reoperation was 7.5 +/- 3.3 years. Predominant cause of reoperation was: structural deterioration of both mitral and tricuspid BPs (6), mitral regurgitation (5), tricuspid BP dysfunction (1), para-aortic leak (1), mitro-aortic thrombi (1). Calcific deposits were the principal cause of early deterioration of mitral BPs and the major cause of late tricuspid BPs dysfunction. This lesion was predominantly related to local factors. Cuspal tears were the principal cause of late (> 9 yrs) mitral BP failure and most probably related to mechanical stress. Extensive fibrosis affected only tricuspid bioprostheses. In 7 patients more extensive degenerative changes occurred in bioprostheses in the mitral rather than the tricuspid position (Group I). However, in the remaining eight the magnitude of the changes was very similar in the two positions (Group II). The interval before reoperation was significantly longer in patients of Group II (9.8 yrs, range 5-13) than patients in Group I (4.9 yrs, range 3-6), (p < 0.01). We concluded that position-related factors exert a major role in bioprosthetic failure. These factors are more deleterious in the mitral position than in the tricuspid position.

Adolescent↗
PubMed1996

Heart transplant for the failing ischaemic ventricle.

Clinical application of heart transplantation goes beyond 28 years experience. Ischaemic heart diseases remain, with idiopathic cardiomyopathies, the main indications for cardiac transplant. A combination of haemodynamic, contractile and viability measurements may be useful to choose between transplant and coronary revascularization for the failing ischaemic ventricle. Advances in the detection of early rejection, improved organ preservation procedures, and the introduction of new immunosuppressive therapy protocols have produced dramatic results in heart transplantation. Late graft atherosclerosis remains a serious threat despite retransplantation and, in some cases, mechanical circulatory support.

Contraindications↗