Showing papers by "Ochsner Medical Center published in 1996"

Coronary Thrombi Increase PTCA Risk Angioscopy as a Clinical Tool

Abstract: Background The presence of angiographically identified intracoronary thrombus has been variably associated with complications after coronary angioplasty. Angiography has been shown to be less sensitive than angioscopy for detecting subtle details of intracoronary morphology, such as intracoronary thrombi. The clinical importance of thrombi detectable by angioscopy but not by angiography is not known. Methods and Results Percutaneous coronary angioscopy was performed in 122 patients undergoing conventional coronary balloon angioplasty (PTCA) at six medical centers. Unstable angina was present in 95 patients (78%) and stable angina in 27 (22%). Therapy was not guided by angioscopic findings, and no patient received thrombolytic therapy as an adjunct to angioplasty. Coronary thrombi were identified in 74 target lesions (61%) by angioscopy versus only 24 (20%) by angiography. A major in-hospital complication (death, myocardial infarction, or emergency bypass surgery) occurred in 10 of 74 patients (14%) with a...

Actuarial survival of heart-lung and bilateral sequential lung transplant recipients with obliterative bronchiolitis.

Abstract: BACKGROUND Obliterative bronchiolitis is a progressive form of obstructive airway disease that threatens long-term survival in lung transplant recipients. Its incidence and the long-term survival of lung transplant recipients with obliterative bronchiolitis are unknown. METHODS The results of 89 heart-lung and 13 bilateral sequential lung transplant survivors beyond 90 days of their operation were analyzed. The date of diagnosis for obliterative bronchiolitis was established histologically (presence of submucosal fibrosis) or physiologically by a persistent reduction in the forced vital capacity to less than 0.7 for greater than 6 weeks. There were 43 patients without obliterative bronchiolitis and 59 patients with obliterative bronchiolitis. RESULTS No differences were found in the mean age and gender ratios between the two groups. The actuarial 1-, 5-, and 10-year percentage freedom from obliterative bronchiolitis was 72 +/- 4.6, 30 +/- 5.6, and 15 +/- 7.4, respectively, with a median onset of 689 days (range 55 to 3404 days). About half the patients with biopsy-proven obliterative bronchiolitis had a fall in their forced expiratory flow at 50% of forced vital capacity/forced vital capacity nearly 4 months before fulfilling the forced expiratory volume in 1 second criteria established by the Working Group on chronic lung dysfunction. The actuarial 1-, 5-, and 10-year percentage survival of obliterative bronchiolitis negative patients was 90 +/- 4.5, 74 +/- 8.4, and 66 +/- 10.6, respectively, versus 90 +/- 3.9, 49 +/- 6.9, and 27 +/- 10.0, respectively, for obliterative bronchiolitis positive patients (p = 0.38). The actuarial 1-, 3-, 5-, 8-, and 10-year percentage survival of lung transplant recipients after the diagnosis of obliterative bronchiolitis was 74 +/- 5.8, 50 +/- 7.5, 43 +/- 7.8, 23 +/- 8.7, and 11 +/- 9.1, respectively, with a median survival of 1084 days (range 0 to 3442 days). CONCLUSIONS The forced expiratory flow at 50% of forced vital capacity/forced vital capacity is a more sensitive indicator for the early detection of obliterative bronchiolitis than the forced expiratory volume in 1 second after heart-lung or bilateral sequential lung transplantation. The obliterative bronchiolitis negative group survival tends to be better than the obliterative bronchiolitis positive group. The obliterative bronchiolitis positive lung transplant recipients have reasonable outcomes with a median survival time of nearly 3 years after the diagnosis of obliterative bronchiolitis. Earlier detection of obliterative bronchiolitis and refinements in management may further improve these results.

Glomerular inflammation induces resistance to tubular injury in the rat. A novel form of acquired, heme oxygenase-dependent resistance to renal injury.

Abstract: Considerable attention is directed to a surprising biologic phenomenon wherein tissues exposed to one insult acquire resistance to another. We identify a novel example of acquired resistance to acute renal failure and a mechanism that contributes to such resistance. Nephrotoxic serum, administered to rats 24 h before the induction of glycerol-induced acute renal failure, reduces functional and structural injury that occurs in this model. Since heme oxygenase, the rate-limiting enzyme in heme degradation, protects against heme protein-induced renal injury, we questioned whether induction of heme oxygenase underlies the protection afforded by nephrotoxic serum. Kidney heme oxygenase (HO-1) mRNA was induced 6 h after nephrotoxic serum and renal tubules were identified as the site of expression of heme oxygenase protein. Induction of heme oxygenase was accompanied by increased renal content of ferritin but not by induction of other antioxidant enzymes. Inhibition of heme oxygenase prevented the protection afforded by nephrotoxic serum. Nephrotoxic serum did not protect against ischemic acute renal failure, a model in which heme oxygenase is not induced. Thus, nephrotoxic serum protects against glycerol-induced acute renal failure by inducing heme oxygenase in tubules. This study provides the first demonstration of resistance to tubular injury acquired from glomerular inflammation, uncovers a mechanism for such resistance, and exposes the dialogue that occurs between glomeruli and tubules.

Risk factors for early, cumulative, and fatal infections after heart transplantation: a multiinstitutional study.

Abstract: Background and Methods : By multivariable analysis, risk factors were identified for initial infection of any type, cumulative infections during the first 6 months and fatal infection among 2210 heart transplant recipients at 30 institutions. Results and Conclusions : Of the 1218 infections in 695 patients, bacterial infections were most frequent (47%), followed by viral (42%), fungal (8%), and protozoal (4%). Risk factors for earlier infection included older recipient age (p 55 years) on ventilator support at time of transplantation who received an older (> 50 years) donor heart.

Gas-generating systems in acute renal allograft rejection in the rat. Co-induction of heme oxygenase and nitric oxide synthase.

Abstract: Gases are now viewed as biologic messengers, and in this regard, carbon monoxide and nitric oxide are incriminated in signaling processes in neural tissue. Carbon monoxide is generated by heme oxygenase (HO), an enzyme inducible by heme, cytokines, and oxidative stress and considered an antioxidant response; nitric oxide is generated by nitric oxide synthase, an enzyme also inducible by cytokines. Since mononuclear cells infiltrate the acutely rejecting kidney, and foster within the kidney oxidative stress and a cytokine-enriched milieu, we examined the expression of these enzymes in acute renal allograft rejection (AR) (Brown Norway kidney to a Lewis rat ; n=17) and in control isografts (Lewis kidney to a Lewis rat ; n=17). No immunosuppressives were used. We found marked induction of HO mRNA and protein in renal allografts at day 5 after transplantation. Prominent expression of HO protein, as detected by immunofluorescence, was observed in the mononuclear cells infiltrating the renal allograft. More than 80% of these cells were macrophages, as identified by positive staining with ED1 antibody. ED1 + cells were rare in isografts and did not stain for HO. We also found co-expression of mRNA and protein for the inducible isoform of nitric oxide synthase (iNOS) in AR at day 5 after transplantation. Induction of HO and iNOS may reflect the cellular effect of diverse cytokines elaborated in the rejecting kidney. HO may enable the macrophage to degrade heme-containing proteins released from erythrocytes and other damaged cells ; alternatively, induction of HO may defend the macrophage against oxidant injury. Increased nitric oxide, as a result of iNOS activity, may antagonize the vasoconstrictive effects of a number of mediators (i.e., thromboxane and endothelin) present in acute rejection ; conversely, nitric oxide may prove cytotoxic through a number of recognized effects. Our studies provide the first demonstration of the induction of HO in the rejecting renal allograft as well as the first demonstration in vivo for the induction of HO in macrophages at the site of an inflammatory response. Such expression, linked as it is to the expression of iNOS, indicates that the macrophage mimics the behavior of neural cells by generating these gaseous messengers ; thus, neural cells are not alone in deploying these mediators. Through a number of effects, these products of HO and iNOS may influence the nature and severity of tissue injury in AR.

Ischemia and atherosclerotic coronary artery disease in patients with hypertrophic cardiomyopathy: a review of incidence, pathophysiological mechanisms, clinical implications and management strategies.

Abstract: Ischemia is suspected to occur frequently in patients with HCM and may result from various mechanisms, for example decreased coronary flow reserve, disease of small intramuscular arteries, "inadequate' size of coronary arteries relative to hypertrophied myocardium, diminution of coronary flow during systole, compression of septal perforator arteries during systole, coronary artery spasm, and co-existent atherosclerotic CAD, which can be present in up to a quarter of HCM patients above 45 years of age. The diagnosis of CAD in patients with HCM is difficult to make on clinical grounds, secondary to the high frequency of angina in patients with HCM without CAD. Pharmacological stress echocardiography is promising but needs to be further studied; stress thallium imaging is beset with frequent false positive results. At this time, coronary angiography remains the only reliable test for the definitive diagnosis of co-existent CAD in HCM. Beta-blockers and verapamil may help in relieving symptoms and silent ischemia in patients with HCM; in those with coexistent CAD and resistant symptoms, CABG alone or in combination with left ventricular myectomy or mitral valve replacement has been recommended.

Antihypertensive therapy: safety and efficacy of drugs and publications.

Abstract: Periodically, in the history of antihypertensive therapeutics, there have been minor tempests that have significantly affected the utilization of entire classes of agents. The first storm struck with the case study report that suggested reserpine and its related compounds were associated with increased risk of carcinoma of the breast.1 Despite its subsequent disproval of this association, the use of these agents was dramatically reduced in favor of newer agents. The second storm was initiated by subanalysis of the MRFIT study,2 from which it was inferred that in a subset of hypertensive patients (those with evidence of electrocardiographic abnormality) diuretic treatment may have been harmful rather than beneficial. Fuel was added to this fire from consecutive meta-analysis of available multicenter antihypertensive drug trials, in which diuretic- or beta-adrenergic receptor blocker-based therapy failed to reduce coronary events to a statistically significant extent. Even when in a further meta-analysis3 a statistically significant reduction was finally attained ( P <.01), it was emphasized that, while a predicted 40 percent reduction in stroke was achieved, the significant 14 percent reduction in coronary morbidity and mortality was definitely lower than the predicted 20 to 25 percent reduction. The results of these publications was an avalanche of speculative talks, articles, and editorials that suggested an adverse effect of diuretics that, either by raising serum lipid levels or by lowering serum potassium, led to a so-called “failure to prevent myocardial infarction.” A subsequent meta-analysis included additional studies which employed lower diuretic doses and reported a reduction in cardiac events satisfying the predicted 25 …

Adenovirus-mediated in vivo gene transfer in a rabbit model of allograft vasculopathy

Abstract: BACKGROUND The long-term success of heart transplantation continues to be in jeopardy because of the development of accelerated vascular myointimal proliferation Transfer of genes encoding products that can modulate the adverse consequences of phenomena that cause myointimal proliferation, into the allograft vessel wall, may modify these pathologic processes The purpose of this study was to assess the feasibility of gene transfer and to evaluate the duration of gene expression in a rabbit heterotopic aortic transplant model of allograft vasculopathy METHODS The abdominal aortas of 32 outbred New Zealand rabbits were harvested and cross-sectionally bisected (n = 64) Six donor and recipient animals were used in a preliminary study to examine neointimal proliferation without accompanying gene transfer Of the remaining 26 rabbits (52 allografts), one half of each allograft aorta was administered a control solution, while the other half was incubated with a replication-defective, recombinant, adenoviral vector-encoding, cytomegalovirus promoter-regulated beta-galactosidase After a 20-minute incubation period, bilateral aorto-carotid transplantations were performed in 26 recipient rabbits All animals received cyclosporine immunosuppression (10 mg/kg/day subcutaneously) The allografts were harvested at 3, 7, 10, 21, and 28 days after transplantation and assayed for beta-galactosidase activity RESULTS Neointimal areas showed an initially slow increase for the first 10 days, followed by a rapid increase up to 21 days, and tended to plateau thereafter Significant beta-galactosidase was apparent in aortic sections dissected from host rabbits for all time points, except at 28 days At the 21-day time point, the aortic section from one rabbit was positive, whereas the other two remained negative However, the one positive section showed intense beta-galactosidase activity, suggesting variability in the experimental model At 28 days, all aortic sections were negative CONCLUSIONS Our findings confirm that genes delivered by this method are expressed for the duration of early rapid intimal proliferation in this heterotopic rabbit model of aortic allograft vasculopathy These findings suggest that this animal model can be used to assess the therapeutic potential of gene transfer at the time of vascular transplantation and may provide a novel therapeutic approach to prevent or ameliorate the genesis of allograft vasculopathy

A rare case of orbital osteogenic sarcoma

Abstract: Osteogenic sarcoma is a malignant bony tumor of mesenchymal cell ori gin. The association of osteogenic sarcoma with Paget's disease of the bone (osteitis deformans) is well-known. However, orbital involvement is rare; only two other cases have been reported in all of the literature. Untreated, the tumor is lethal, with death usually occurring from extension into the cranial fossa. Report of a Case. A 58-year-old man was seen for a 1-month history of diplopia, pain on eye movement, and left upper eyelid ptosis. Of significance in his medical history was Paget's disease of the bone for 23 years and no prior radiation therapy. A review of systems was unremarkable. The ophthalmic evaluation revealed a best-corrected visual acuity of 20/30 OD and 20/80 OS. The left eyelid demonstrated 3 mm of ptosis. Additionally, a 3-mm axial proptosis was present, and the globe was displaced 8 mm laterally and 4 mm inferiorly.

Antihypertensive therapy: safety and efficacy of drugs and publications.

Abstract: Periodically, in the history of antihypertensive therapeutics, there have been minor tempests that have significantly affected the utilization of entire classes of agents. The first storm struck with the case study report that suggested reserpine and its related compounds were associated with increased risk of carcinoma of the breast.1 Despite its subsequent disproval of this association, the use of these agents was dramatically reduced in favor of newer agents. The second storm was initiated by subanalysis of the MRFIT study,2 from which it was inferred that in a subset of hypertensive patients (those with evidence of electrocardiographic abnormality) diuretic treatment may have been harmful rather than beneficial. Fuel was added to this fire from consecutive meta-analysis of available multicenter antihypertensive drug trials, in which diuretic- or beta-adrenergic receptor blocker-based therapy failed to reduce coronary events to a statistically significant extent. Even when in a further meta-analysis3 a statistically significant reduction was finally attained ( P <.01), it was emphasized that, while a predicted 40 percent reduction in stroke was achieved, the significant 14 percent reduction in coronary morbidity and mortality was definitely lower than the predicted 20 to 25 percent reduction. The results of these publications was an avalanche of speculative talks, articles, and editorials that suggested an adverse effect of diuretics that, either by raising serum lipid levels or by lowering serum potassium, led to a so-called “failure to prevent myocardial infarction.” A subsequent meta-analysis included additional studies which employed lower diuretic doses and reported a reduction in cardiac events satisfying the predicted 25 …

On-Line Myocardial Tissue Characterization with a New Commercially Produced Software.

Abstract: Myocardial tissue characterization has been performed using various ultrasonic techniques, one of which is the cyclic variation of integrated backscatter, a method that analyzes the acoustic properties of the myocardium using backscattered radiofrequency signals to provide information about myocardial structure and function. Previous studies using prototype equipment have demonstrated a reduction in the cardiac cycle variation of integrated backscatter in various pathologic states. Recently, a commercially produced software package that allows online analysis of cyclic variation of integrated backscatter has been made available for testing by various investigators. To evaluate this new commercially produced software, we compared integrated backscatter results in three groups of patients: a control group; an end-stage cardiomyopathy group; and a heart transplant recipient group. Integrated backscatter of the septum and posterior walls in the parasternal long axis and 12, 3, 6, and 9 o'clock regions in the short axis was performed using a commercially produced program (Hewlett-Packard Sonos 1500). In the control group, the mean cyclic variation of integrated backscatter was 5.04 +/- 1.60 dB in the septum and did not significantly vary from the rest of the regions studied. In comparison, cyclic variation of integrated backscatter in every region studied was reduced in the cardiomyopathy and heart transplant groups. Intraobserver variability, interobserver variability, and reproducibility over a 3-month interval was found to be 6.5%, 5.7%, and 7.5%, respectively. These results indicate that: (1) online analysis of cardiac cyclic variation of integrated backscatter is possible utilizing commercially produced software; (2) results obtained are consistent with a low intraobserver and interobserver variability and are reproducible over time; and (3) as observed in the comparison between the transplant and control groups, this information may detect changes in cardiac structure even in the absence of changes in function. (ECHOCARDIOGRAPHY, Volume 13, May 1996)

Assessment of renal perfusion in a canine model using FSO69, a new transpulmonary echo-contrast agent

Abstract: We have previously demonstrated the safety and efficacy of FS069, a new transpulmonary echocontrast agent, for myocardial opacification. To our knowledge, no information exists regarding the use of this agent for transcutaneous assessment of renal perfusion. We studied 14 mongrel dogs using intravenously administered FS069. Renal ultrasound imaging was performed with a Hewlett‐Packard Sonos 1500 using a 3.5‐MHz transducer. Renal blood flow (ReBF) was altered using renal artery occlusion in four dogs and dipyridamole (0.56 rag / kg IV) in ten dogs. Renal perfusion was quantitatively assessed before and after each intervention using background subtracted peak intensity. ReBF was assessed with radiolabeled microspheres in ten dogs. Renal opacification was observed in all 14 dogs at baseline. The intravenous contrast dose required to produce optimal renal opacification ranged from 0.3–0.7 cc. After renal artery occlusion, peak intensity was reduced from 5.4 ± 5.8 to 0.93 ± 1.1 units (r = 0.99, P < 0.008). As expected, blood pressure and ReBF dropped in all ten dogs after dipyridamole administration. Interestingly, peak intensity increased in all but one dog. An inverse correlation (r = ‐0.75, P = 0.02) was observed between ReBF and peak intensity (percent change from baseline). The inverse relation between ReBF and peak intensity observed suggests vasocon‐striction of the afferent arterioles in response to dipyridamole and a reduced clearance of the contrast. These findings are in agreement with previous data demonstrating decreased renal thallium clearance postdipyridamole administration. Our data document the feasibility to assess renal perfusion under various flow states after intravenous injection of FS069.