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Biomedical subjects

G M Deeb

Publications and source records attributed to G M Deeb.

96 records · Page 6Linked to original sources

Automatic internal cardioverter defibrillator: a bridge to heart transplantation.

The automatic internal cardioverter defibrillator (AICD) is effective in preventing death in patients with malignant ventricular arrhythmias (VT/VF) refractory to medical therapy. Because of the long waiting period for heart transplantation and the high likelihood of sudden arrhythmic death in this population, this study was undertaken to assess the value of the AICD in patients awaiting heart transplantation who have refractory VT/VF. Fourteen patients awaiting heart transplantation who had a history of VT/VF underwent AICD implantation (10 extrapericardial and four intrapericardial) via median sternotomy. All patients survived the AICD implantation and have either had heart transplantation or await transplantation at present (1 to 24 months after AICD implantation). Twelve of these patients have received a mean of 10 AICD shocks (range, 0 to 32). One patient received 19 shocks in the 24-hour period before transplantation. Two patients have died of progressive heart failure. Five patients have gone on to successful transplantation, and seven patients await heart transplantation with a functioning AICD in place. In conclusion, the AICD represents a new "bridge" to heart transplantation that is well tolerated by these high-risk patients, avoids drug side effects, and is efficacious in aborting sudden death, thereby allowing them to undergo successful heart transplantation.

Actuarial Analysis↗

Clinical experience with the Nimbus pump.

The Nimbus pump is an indwelling, electromagnetic powered left ventricular (LV) assist device inserted transfemorally. The inflow cannula (7 mm) is positioned across the aortic valve and the pump in the descending aorta. Indications for insertion include cardiogenic shock despite maximal medical support and PCWP greater than 18 mmHg, MAP less than 90 mmHg, and Cl less than 2 L/min/m2. Twelve patients underwent the attempt at surgical insertion of the Nimbus pump. Diagnoses included eight acute myocardial infarctions (AMI), two ischemic cardiomyopathy, one postpartum cardiomyopathy, and one transplanted heart rejection. Eight (67%) of twelve patients had successful insertion. One patient had peripheral vascular disease preventing passage, and three had femoral vessels too small for insertion (less than 7.5 Hagar dilator). Five patients with the diagnosis of AMI had successful insertion and three (60%) underwent sufficient LV recovery for removal of the device; the other two patients died of stroke and ventricular arrhythmias, respectively. Three patients with the diagnosis of cardiomyopathy had progression of the disease process, and their needs exceeded the capabilities of the pump and they died of multiorgan failure. The Nimbus pump is an attractive LV assist device because of its pumping capacity (3.5 L/min) and minor surgical procedure for insertion. However, its application is limited because of access route and size. The device appears to work well for patients in cardiogenic shock after AMI (60% recovery) but does not appear indicated for patients with cadiomyopathy.

Adult↗

Methylprednisolone pulsing of heart transplant patients in the home.

Methylprednisolone pulsing is the first form of treatment used to reverse acute moderate rejection in heart transplant patients at the University of Michigan, Ann Arbor. Before May 1986, patients who needed administration of medications to be pulsed were admitted to the hospital. With our increasing number of transplant patients, lack of hospital beds, and efforts toward cost containment, a new system was established. From June 1986 to April 1988, 53 heart transplantations were performed in 40 adults and 13 children. Home care agency nurses received in-service training by the heart transplant clinical specialist. Insurance companies were contacted directly to obtain financial approval when it was not considered a covered benefit. Of 47 episodes of rejection, 45 were successfully treated in the home with resolution, whereas hospital admission was required in two cases of rejection episodes for successful resolution. There were marked financial savings, increased patient satisfaction, no patient infections, and minimal side effects, which included hypertension in five patients, headaches in two patients, and difficulty gaining venous access in two patients. Most problems were easily handled by telephone communication. Therefore, after a 22-month experience with administration of methylprednisolone pulses in the home, we believe that this is a satisfactory method of treating patients. It is cost-effective, has minimal side effects, and leads to increased patient satisfaction.

Costs and Cost Analysis↗

Cytoimmunologic monitoring and heart transplantation.

Cytoimmunologic monitoring (CIM) combines morphological quantitation of activated lymphocytes and immunoblasts with immunophenotyping of peripheral blood in an effort to identify patients at risk for heart transplant rejection. In this study, CIM and endomyocardial biopsy (EMB) results were correlated in 55 paired blood and tissue specimens obtained from 18 heart transplant patients after operation. We found that 83% of patients with rejection and 81% of patients without rejection had increased levels of morphological activated lymphocytes. Multiple other criteria for determining levels of activation were used without improving the sensitivity or specificity. The use of CD4:CD8 ratios to discriminate between activation caused by rejection and those from viral infections and other inflammatory conditions yielded a sensitivity of 43% and specificity of 56%. The presence of activation markers such as I2, TAC, and T9 did not correlate with either CIM or EMB findings. CD4:CD8 alone was not predictive of cardiac rejection as increased, normal, and decreased CD4:CD8 ratios were seen in patients with and without rejection. Other measurements such as percentage of activated lymphocytes, total lymphocyte count, and whole blood cell count did not correlate with EMB or immunophenotypic findings. These results indicate that neither CIM, as currently conducted, nor immunophenotyping alone is sensitive or specific enough to substitute for EMB in screening for tissue rejection.

Antibodies, Monoclonal↗

Antithymocyte gamma globulin, low-dosage cyclosporine, and tapering steroids as an immunosuppressive regimen to avoid early kidney failure in heart transplantation.

Cyclosporine is a powerful immunosuppressive agent that unfortunately has significant renal toxicity. Two risk factors associated with a high incidence of kidney failure in patients receiving cyclosporine have been described in the literature. In an effort to decrease the possibility of renal toxicity with the use of cyclosporine, we use low-dosage cyclosporine, antithymocyte gamma globulin, and tapering dosages of steroids as an immunosuppressive regimen. Twenty-one patients had orthotopic heart transplants from January 1985 to January 1986. Sixteen of 21 patients or 70% had at least one high risk factor for kidney failure. There were no episodes of acute kidney failure, and the blood urea nitrogen and creatinine levels that were recorded over an average of 8.5 months per patient did not increase significantly from preoperative values. Seventeen of 21 or 81% of the patients are alive and functioning fully. The incidence of rejection per patient was 0.9, and there were no biopsy-proven severe rejections. One patient died at 5 months; the autopsy showed generalized moderate rejection. There were 0.24 episodes of infection per patient, with one patient who died from Pneumocystis pneumonia. With this immunosuppression protocol, early postoperative kidney dysfunction was avoided. The incidences of rejection and infection were within acceptable range, and the quality of life in the 17 survivors is excellent.

Acute Kidney Injury↗