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Biomedical subjects

B Radovancevic

Publications and source records attributed to B Radovancevic.

At least 55 records · Page 3Linked to original sources
PubMed1996

Sudden cardiac death in cardiac transplant recipients.

BACKGROUND: Sudden cardiac death (SCD) remains a significant cause of mortality in the general population. Its role in cardiac transplant patients-including its incidence, mechanism, potential risk factors, or influence on survival in this patient population-has not been well described. METHODS AND RESULTS: We undertook a retrospective analysis of the clinical and autopsy records of 257 patient deaths. SCD was analyzed in relation to severity and frequency of rejection episodes, clinical history of arrhythmias, coronary artery disease (CAD), hypertension, diabetes, left ventricular dysfunction, and clinical history of premorbid symptoms. A total of 25 patients were identified as having died of SCD, an incidence of 9.7%: 20% died < or = 12 months after transplantation, 80% died after > 12 months, and 20% died after > or = 60 months. Patient survival ranged from 2.5 to 138 months (mean, 45.7 months). The mean number of rejection episodes per patient was 2.6, most occurring within 12 months after transplantation. Echocardiography or multigated acquisition scan revealed an ejection fraction (EF) > or = 50% in 68% of patients; however, the presence of arrhythmias, primarily atrial, was evident in 68% of patients and was equally distributed between patients with EFs > or = 50% and EFs < 50%. CAD was present in 53% of patients (10 of 19) whose angiograms were available, and the appearance of CAD after transplantation was between 29 and 85 months (mean, 51.4 months). Of the 9 patients with normal cardiac catheterization studies, 6 with available autopsy reports had documented CAD. Autopsy data in 13 of 25 patients revealed CAD in 92% and rejection in 15% (International Society for Heart and Lung Transplantation grade > 3A). Of the deaths, 64% occurred within 3 months of the last endomyocardial biopsy, 96% had normal biopsies, and the only rejection was without hemodynamic compromise. CONCLUSIONS: SCD occurs relatively frequently in the cardiac transplant population, and CAD is present in most of the patients. Because the frequency of arrhythmias is relatively high in this group, more aggressive antiarrhythmic therapy may be beneficial for patients with allograft CAD in the prevention of SCD.

Adult↗
PubMed1996

Treatment of hyperlipidemia after heart transplantation and rationale for the Heart Transplant Lipid Registry.

Hyperlipidemia occurs frequently after heart transplantation, and accelerated coronary artery disease remains the major cause of morbidity and mortality in patients who survive more than 1 year after heart transplantation. However, the risks and benefits of lipid-lowering therapy after heart transplantation remain poorly defined, and national guidelines for lipid-lowering drug therapy do not specifically address treatment of dyslipidemia in transplant recipients. Since the initial reports in the 1980s of rhabdomyolysis in heart transplant patients receiving high-dosage lovastatin, results of 11 post-transplantation series that used lovastatin, simvastatin, or pravastatin at lower dosages as drug monotherapy have been published. These studies have shown an overall 1% incidence of rhabdomyolysis, defined as creatine kinase > 10 times the upper limit of normal plus muscle symptoms. One randomized, controlled prospective trial has investigated the effects of lipid-lowering pharmacotherapy on patient outcome in cardiac transplant recipients. At 1-year follow-up in this nonblinded, single-center trial, patients treated with pravastatin (20 or 40 mg/day) initiated within 2 weeks of transplantation had a significant reduction in mortality rate and a significantly lower incidence of transplant arteriopathy. A number of important issues remain unanswered regarding treatment guidelines in patients with hyperlipidemia after heart transplantation. In January 1995 we began the Heart Transplant Lipid Registry, with 12 participant centers, to gather data prospectively on the efficacy and safety of lipid-lowering drugs in the treatment of dyslipidemia after heart transplantation.

Anticholesteremic Agents↗
PubMed1996

Improved left ventricular function after chronic left ventricular unloading.

BACKGROUND: This study assessed the effect of prolonged left ventricular unloading on native ventricular function. METHODS: We reviewed data from 31 patients (30 men, 1 woman) supported more than 30 days (mean, 137 days; range, 31 to 505 days) with the HeartMate left ventricular assist system. The patients' mean age was 46 years (range, 22 to 64 years); 17 had idiopathic and 14 had ischemic cardiomyopathy. Data (anatomic, physiologic, hemodynamic, histologic, and biochemical) were collected at the time of HeartMate implantation, during support with the device temporarily off, and at the time of device explantation. RESULTS: Routine chest roentgenogram showed improvement in cardiothoracic ratio (0.62 +/- 0.04 to 0.55 +/- 0.03; p < 0.0001). Echocardiography performed with the pump off showed a significant decrease in left ventricular end-diastolic dimension (6.81 +/- 0.87 cm to 5.39 +/- 1.08 cm; p < 0.0005) and a significant improvement in ejection fraction (0.11 +/- 0.05 to 0.22 +/- 0.17; p < 0.02). Cardiac index increased (1.96 +/- 0.52 L.min-1.m-2 to 2.93 +/- 0.73 L.min-1.m-2; p < 0.0001), mean aortic pressure increased (71.40 +/- 10.63 mm Hg to 76.33 +/- 16.84 mm Hg; p = 0.48), pulmonary capillary wedge pressure decreased (24.18 +/- 6.27 mm Hg to 14.48 +/- 3.01 mm Hg; p < 0.0001), and pulmonary vascular resistance decreased (3.34 +/- 2.00 Wood units to 2.51 +/- 0.88 Wood units; p < 0.05). Comparisons of tissue samples taken at the time of implantation and at the time of transplantation showed a marked reduction in myocytolysis. Calcium uptake, calcium-binding rates, and lipid levels normalized in patients studied. Plasma norepinephrine levels decreased to near normal levels. CONCLUSION: Prospective studies are now indicated to determine whether device removal without transplantation may be beneficial in selected patients.

Adult↗
PubMed1996

Diagnosis, surveillance, and epidemiologic evaluation of viral infections in pediatric cardiac transplant recipients with the use of the polymerase chain reaction.

BACKGROUND: Viral infections, particularly those caused by cytomegalovirus, are a major cause of postoperative morbidity and mortality in heart transplant recipients. These infections have classically been diagnosed by history, physical examination, peripheral viral cultures, and serologic studies. These methods are often time-consuming and lack sensitivity. Positive viral cultures from the heart are rarely obtained, and viral myocarditis and acute cellular rejection are unable to be differentiated histologically. We have therefore used the polymerse chain reaction to diagnose possible viral infection in pediatric heart transplant recipients with findings consistent with acute unexplained rejection. METHODS: Polymerase chain reaction was used as an aid to diagnose cytomegalovirus infection of cardiac tissue obtained by right ventricular endomyocardial biopsy and follow its long-term course. In addition, polymerase chain reaction was used to diagnose infection of the heart by other viruses in patients with clinical and histologic evidence of rejection, especially those with unexplained late rejection or chronic rejection. Polymerase chain reaction primers were designed to amplify nucleic acid sequences from cytomegalovirus, parvovirus, adenovirus, herpes simplex virus, Epstein-Barr virus, and the RNA viruses of the Enterovirus family. RESULTS: Forty patients underwent serial right ventricular endomyocardial biopsy (129 samples) for rejection surveillance with positive results obtained in 41 samples (32%) from 21 patients. Viral genome amplified included cytomegalovirus in 16 samples, adenovirus in 14, enterovirus in 6, parvovirus in 3, and herpes simplex virus in 2. In 13 of the 21 patients positive for viral genome (62%), endomyocardial biopsy histologic scores were consistent with multifocal moderate to severe rejection (Internal Society for Heart and Lung Transplantation scores of 3A or greater). CONCLUSIONS: Polymerase chain reactions may be used as a rapid and sensitive method to evaluate postoperative viral infections in heart transplant recipients, especially in those with late-onset rejection or chronic rejection. Polymerase chain reaction may also be useful in the serial analysis of cytomegalovirus status in transplant recipients. The use of multiple viral primers improves the diagnostic evaluation of these patients and may lead to a better understanding of the epidemiologic characteristics of posttransplantation viral infections and the cause of late or chronic rejection.

Adenoviruses, Human↗
PubMed1994

The relationship among donor-recipient HLA mismatches, rejection, and death from coronary artery disease in cardiac transplant recipients.

Review of 448 cyclosporine-treated heart transplant recipients was undertaken to examine the relationship of donor-recipient HLA compatibility to patient survival, rejection, and death from coronary artery disease (CAD). Pre-Tx crossmatching and panel-reactive antibody (PRA) were correlated to survival as well. Overall patient survivals were 78%, 70%, and 65% at 1,3, and 5 years post-Tx, respectively. Matching of donor-recipient HLA did not improve outcome in that 1,3, and 5 years survivals for well-matched (< or = 2 A, B, or 0-1 DR mismatches [MMs]) vs. poorly matched (> 2 A, B, or 2 DR MMs) recipients were comparable and not significantly different. Well-matched recipients, however, experienced significantly fewer rejections (1.06 +/- 1.2 vs. 1.96 +/- 1.0, P < 0.01 for < or = 2 A, BMMs vs. > 2 A, B MMs and 1.1 +/- 0.9 vs. 2.0 +/- 1.1 for 0-1 DR MMs vs. 2 DR MMs, P < 0.01). Moreover, HLA-DR, but not HLA A, B was a significant (P < 0.01) predictor of early rejection (<30 days) in that 65% (165/254) of poorly matched vs. only 40% (95/194) of well-matched HLA-DR recipients experienced early rejections. Interestingly, an inverse relationship was found between HLA A and B MM, but not HLA-DR MM, and death from coronary artery disease in that 17% (19/11) of well matched vs 9% (32/327) of poorly matched patients died from CAD. Pre-Tx PRA did not impact patient survival or rejection. Donor-recipient crossmatching was performed utilizing the NIH and/or antiglobulin (AHG) procedures. No survival differences were observed at 1, 2, and 3 years post-Tx when comparing outcome for the 24 NIH crossmatch (XM)-positive (+) with the 424 NIH-XM-negative displayed a positive AHG recipient antidonor displayed a positive AHG recipient antidonor reactivity. When these 10 AHG-XM (+) sera were treated with dithioerythritol (to inactivate IgM) all 10 converted to a negative reactivity, indicating that a positive crossmatch due to IgM reactivity should not be considered a contraindication to cardiac transplantation. These data also suggest that the reactivity of the 24 NIH-XM(+) sera were most likely due to IgM, and that poorly matched heart recipients may benefit from a more aggressive immunosuppressive regimen to prevent early rejections.

Adolescent↗
PubMed1994

Intermediate follow-up of pediatric heart transplant recipients with elevated pulmonary vascular resistance index.

OBJECTIVES: This study examined perioperative and intermediate outcomes in pediatric cardiac transplant recipients who had elevated pulmonary vascular resistance indexes preoperatively. BACKGROUND: Elevated pulmonary vascular resistance was associated with poor outcome in previous studies and constitutes a relative contraindication to transplantation. Few studies have evaluated this poor outcome risk factor in pediatric patients. METHODS: To evaluate outcomes of nonneonatal transplant recipients, records were reviewed and divided into Group I (preoperative pulmonary vascular resistance index > or = 6 units.m2) and Group II (pulmonary vascular resistance index < 6 units.m2). Donor/recipient weight ratios, ischemic times, length of intensive care unit stay, posttransplantation infection rates, arrhythmia, response to pretransplantation vasodilator infusions and pulmonary vascular resistance indexes at the first and most recent posttransplantation biopsies were analyzed. RESULTS: Group I (8 patients) had a mean (+/- SEM) pulmonary vascular resistance index of 11.5 +/- 3.5 units,m2; Group II (29 patients) had a mean pulmonary vascular resistance index of 2.3 +/- 0.4 units,m2 (p < 0.002). Pulmonary vascular resistance index decreased from 12.3 +/- 3.9 to 3.9 +/- 0.9 units.m2 (p < 0.05) in 7 Group I patients undergoing vasodilator infusion during pretransplantation catheterization. Thirty-six orthotopic heart transplantations were performed and one heterotopic transplantation. Donor weights exceeded recipient weights by 13% and 31% for Groups I and II, respectively (p > 0.25). Donor ischemic time was 215 min for Group I and 225 min for Group II (p > 0.75). Intensive care unit stay was 11.5 days in Group I and 15.1 days in Group II (p = 0.20). Infection rate was 38% in both groups (p > 0.80). Arrhythmias occurred in 90% of Group I and 42% in Group II (p < 0.03) patients. Pulmonary resistance index in Group I decreased from 11.5 +/- 3.5 to 3.3 +/- 1.2 units.m2 (p < 0.03) by the first posttransplantation biopsy and have not changed subsequently. During 2.3 years (range 0.3 to 8.5) of follow-up, the mortality rate was 25% and 21% for Groups I and II, respectively (p > 0.80). CONCLUSIONS: Group I patients did not require significantly oversized donors, restricted donor locations or longer intensive care unit stays or have higher infection rates; however, arrhythmias were more frequent. Pulmonary resistance index normalized early after transplantation. Pulmonary vascular reactivity may be more important for survival than absolute resistance index.

Adolescent↗
PubMed1994

Mechanical circulatory support in children.

Nine children (aged 1.2-15 years) have been treated with mechanical circulatory support devices at our institution. Indications for treatment were acute cardiac allograft rejection (n = 4), postcardiotomy cardiogenic shock (n = 4), and bridge to cardiac transplantation (n = 1). Eight patients required left ventricular support, and one required biventricular support. A BioMedicus centrifugal pump was used in eight patients, and a Hemopump intra-aortic axial flow device was used in one patient. In two patients, an intra-aortic balloon pump was in place at the time that circulatory support was instituted. Mechanical support time ranged from 2 to 139 h, and the average flow index was 2.31 l/min per m2. Three patients required hemodialysis during support, and one patient required re-exploration because of mediastinal hemorrhage. Recovery of native ventricular function was assessed by transthoracic or transesophageal echocardiography, and weaning from the device was achieved by gradually decreasing pump flow in increments of 0.1 to 0.5 l/min. Seven patients were successfully weaned from support. Two hospital deaths occurred after circulatory support had been discontinued: one patient died of respiratory failure and the other of gram-negative pneumonia and sepsis. The five surviving patients experienced no significant complications, and their hemodynamic indices were normal at the time of discharge. At a mean follow-up of 28.8 months, these patients are leading active unrestricted lives, with no long-term device-related sequelae. Based on this experience, mechanical circulatory support is feasible in children who experience profound circulatory failure from a variety of causes.

Adolescent↗
PubMed1993

Improved multiorgan function after prolonged univentricular support.

Eleven cardiac transplant candidates (all male; mean age, 43.3 years) with multiorgan (hepatic, pulmonary, and/or renal) dysfunction were sustained for prolonged periods (> 30 days) with the HeartMate (Thermo Cardiosystems, Inc, Woburn, MA) left ventricular assist device. We evaluated the effect of extended support on end-organ recovery and on the ultimate outcome of cardiac transplantation. In addition to cardiac failure, 9 patients had hepatic dysfunction, 8 had pulmonary dysfunction, and 6 had renal dysfunction (4 of whom required hemodialysis before left ventricular assist device support). Mean duration of support was 115 days (range, 31 to 233 days). All patients underwent successful transplantation; 10 of these patients survived a mean of 24 months. One patient, who had required hemodialysis and ventilatory support during and after support, experienced progressive multiorgan failure and died 7 weeks after transplantation. Two late deaths after transplantation were unrelated to the device. Overall, patients experienced improvement in cardiac functional class status, and most participated in cardiac rehabilitation programs before transplantation. During left ventricular assist device support, hepatic function returned to normal in 8 patients, pulmonary function recovered in 7, and renal function returned to normal in 4. One patient who required hemodialysis underwent renal transplantation after cardiac transplantation and had complete recovery of renal function. In the current era of donor shortages, gravely ill patients can benefit from a strategy of prolonged left ventricular assist device support. This strategy has proved safe, has allowed for reversal of multiorgan dysfunction, and has produced healthier transplant candidates.

Adult↗
PubMed1993

Postcardiotomy LVAD support and transesophageal echocardiography in a child.

A case of postcardiotomy cardiogenic shock after repair of a congenital ventricular septal defect in a 5-year-old boy is reported. Mechanical circulatory support, instituted with a centrifugal left ventricular assist device, adequately supported the patient for 50 hours until recovery of native left ventricular function occurred. Transesophageal echocardiography proved to be useful in assessment of left ventricular function, allowing for timely institution and withdrawal of mechanical circulatory support.

Child, Preschool↗
PubMed1992

True aneurysm of the saphenous vein graft stump associated with CABG in a cardiac transplant patient.

Aneurysm of a saphenous vein graft after coronary artery bypass requires surgical resection because of its potential for rupture. This report describes a case of aneurysm formation in a 55-year-old man who underwent coronary artery bypass operation in 1977 and orthotopic heart transplantation 7 years later. A proximal vein graft remnant that had been ligated at the time of transplantation developed into a 5-cm aneurysm. In patients who have undergone previous coronary artery bypass operation, we recommend that the entire vein graft stump be excised and oversewn at the aortosaphenous anastomosis at the time of transplantation.

Aneurysm↗
PubMed1992

Hyperlipidemia after heart transplantation: report of a 6-year experience, with treatment recommendations.

Mean plasma lipid values in 100 patients who survived greater than 3 months after heart transplantation increased significantly at 3 months over pretransplantation values: total cholesterol from 168 +/- 7 to 234 +/- 7 mg/dl, low density lipoprotein (LDL) cholesterol from 111 +/- 6 to 148 +/- 6 mg/dl, high density lipoprotein (HDL) cholesterol from 34 +/- 1 to 47 +/- 1 mg/dl and triglycerides from 107 +/- 6 to 195 +/- 10 mg/dl. There were no significant increases after this time. The LDL cholesterol values reamined greater than or equal to 130 mg/dl in 64% of patients and triglyceride values remained greater than or equal to 200 mg/dl in 41% of patients 6 months after postoperative dietary instructions. Beginning in 1985, select patients whose total cholesterol values remained greater than 300 mg/dl despite 6 months of dietary intervention were treated with lovastatin given alone in a high dose (40 to 80 mg/day) or in combination with another hypolipidemic agent. Four of the five patients so treated developed rhabdomyolysis; two of the four had acute renal failure. Beginning in 1988, a second protocol--lovastatin at 20 mg/day as monotherapy--was used in patients who despite dietary intervention had total cholesterol greater than 240 mg/dl (mean follow-up 13 months). In the 15 patients so treated, mean total cholesterol decreased from 299 +/- 10 mg/dl before treatment with lovastatin to 235 +/- 9 mg/dl during treatment (21% reduction, p less than 0.001) and mean LDL cholesterol was reduced from a baseline value of 190 +/- 10 to 132 +/- 12 mg/dl during treatment (31% reduction, p less than 0.001). In this study, lovastatin at a dose of less than or equal to 20 mg/day as monotherapy was a well tolerated, effective treatment for hyperlipidemia after heart transplantation. It did not result in rhabdomyolysis and required no alteration in immunosuppressive therapy. However, the dose should not exceed 20 mg/day and combination therapy with either gemfibrozil or nicotinic acid should be avoided, even if the target LDL cholesterol value is not reached.

Analysis of Variance↗
PubMed1992

Implantation technique for the HeartMate left ventricular assist device.

The technique for implanting the HeartMate, an intraabdominally placed, pulsatile left ventricular assist device, is described. This device, which has been developed for potential use in patients requiring permanent left ventricular assistance, is currently undergoing clinical investigation in patients requiring temporary support as they await cardiac transplantation. This clinical experience has demonstrated device safety and efficacy, even for patients requiring extended periods of support.

Abdomen↗
PubMed1992

Recovery of pulmonary function in patients undergoing extended left ventricular assistance.

Heart transplantation should follow the implantation of a left ventricular assist device (LVAD) only after optimal postoperative recovery of pulmonary function. We reviewed hospital records of 12 patients who underwent extended (greater than 30 days) left ventricular support before transplantation to determine the rate of return of pulmonary function. The mean cardiac index and pulmonary capillary wedge pressure returned to normal in all patients within three days after LVAD implantation. The mean pulmonary artery pressure and pulmonary vascular resistance decreased but did not return to normal. The mean central venous pressure remained elevated throughout the first month but decreased by the time of transplantation. Supplemental oxygen requirements and peak airway pressures improved, and ten of the 12 patients were extubated by the fifth postoperative day. Preoperative roentgenographic evidence of pulmonary edema was present in eight patients, and pulmonary hilar prominence was present in the remaining four patients. Roentgenographic resolution of the pulmonary edema occurred slowly, persisting for one week after surgery in seven of eight patients. Ten patients were able to exercise strenuously 30 days after surgery, and 11 were returned to excellent condition before undergoing heart transplantation. Although the hemodynamic status in these patients significantly improved shortly after LVAD implantation, optimal recovery of pulmonary function required several weeks. Therefore, we advocate delaying transplantation after LVAD implantation to allow optimal pulmonary recovery.

Adult↗
PubMed1991

Lipoprotein(a) and apolipoprotein changes after cardiac transplantation.

Although lipoprotein changes after cardiac transplantation have been documented, the effects of transplantation and subsequent immunosuppressive therapy (particularly the combination of prednisone, azathioprine and cyclosporine) on apolipoprotein levels and lipoprotein(a) have not been reported. Fasting cholesterol, triglycerides, high density lipoprotein (HDL) cholesterol, low density lipoprotein (LDL) cholesterol, apolipoprotein A-1 and B-100 and lipoprotein(a) were evaluated in 69 consecutive patients during the waiting period before cardiac transplantation. There were 28 deaths before donor organ identification and 41 patients received a cardiac allograft. The lipoprotein levels of transplant recipients were again assayed 3 months postoperatively. Mean (+/- SEM) values increased for total plasma cholesterol (from 180 +/- 8 to 228 +/- 8 mg/dl, p less than or equal to 0.001), triglycerides (from 126 +/- 11 to 207 +/- 14 mg/dl; p less than or equal to 0.001), HDL cholesterol (from 39 +/- 2 to 49 +/- 3 mg/dl; p less than or equal to 0.002) and LDL cholesterol (from 119 +/- 7 to 138 +/- 7 mg/dl; p less than 0.02). Apolipoprotein A-1 and B-100 also increased, but lipoprotein(a) decreased from 11.7 +/- 1.7 to 6.8 +/- 1.1 mg/dl; p less than or equal to 0.0001) after transplantation. Although total cholesterol, triglycerides, LDL cholesterol, apolipoprotein A-1 and B-100 increased dramatically after cardiac transplantation, so did HDL cholesterol, thereby keeping the LDL/HDL cholesterol ratio constant. The surprising decrease in lipoprotein(a) after cardiac transplantation suggests that metabolism of lipoprotein(a) is independent of LDL cholesterol and that immunosuppressive drugs either decrease the synthesis or increase catabolism of lipoprotein(a).

Apolipoproteins↗
PubMed1991

Cardiac transplantation in Puerto Rican patients at the Texas Heart Institute.

Cardiac transplantation is the treatment of choice for patients suffering from end-stage cardiac disease unamenable to conventional medical or surgical treatment. More than 390 patients have undergone heart transplantation at the Texas Heart Institute in Houston, and nine were Puerto Rican. Overall survival of these patients is 88%. Our experience with patients from Puerto Rico is described.

Age Factors↗