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Biomedical subjects

D K Cooper

Publications and source records attributed to D K Cooper.

At least 181 records · Page 10Linked to original sources
PubMed1991

The implantable cardioverter-defibrillator: clinical results.

To evaluate the effectiveness of the automatic implantable cardioverter-defibrillator (AICD), a 7-year experience, from 1983-1990, was reviewed. A total of 111 patients received an AICD device. Their ages ranged between 8 and 83 years. Mean age was 63.9 years. There were 91 men and 20 women. Eighty of the patients received the AICD following an out-of-hospital cardiac arrest, while 31 were suffering from intermittent symptomatic ventricular tachycardia. The underlying etiology in 97 patients (87%) was ischemic coronary artery disease, in 11 patients (10%) dilated cardiomyopathy, and in 3 patients (3%) idiopathic ventricular fibrillation. Mean ejection fraction was 33.2%. Implantation of the AICD was performed via a left thoracotomy in 39 patients, median sternotomy in 49 patients and subxiphoid-subcostal approach in 23 patients. In-hospital mortality occurred in one patient who suffered an acute myocardial infarction 4 hours postoperatively. Out-of-hospital mortality was observed in 19 patients. There were two arrhythmic deaths. Follow-up was available for 107 patients. Mean follow-up was 33.1 months. Sixty-six patients (62%) had AICD shocks. The initial appropriate shocks occurred during the first postimplantation year in 91% of the patients. In 53 of the survivors, initial AICD shocks took place within 4.4 +/- 4.7 months from implantation. Thirteen of the 20 patients who died had received appropriate AICD shocks. In these patients, the time between implantation and first shock was 2.7 +/- 3.6 months whereas the time between implantation and death was 11.3 +/- 10.3 months (NS). We conclude that the AICD is effective in converting ventricular tachyarrhythmias and prolongs survival.

Electric Countershock↗
PubMed1991

The gastrointestinal management of patients undergoing heart transplantation.

Between March 1985 and December 1989, 86 patients underwent heart (80) or heart-lung (6) transplantation. Thirty-seven (43%) developed one or more significant gastrointestinal problems. Dyspepsia and gallbladder disease were common, but easily managed. Cytomegalovirus disease occurred in 25 patients (29%) and required aggressive investigation and early therapy with ganciclovir; all patients so treated responded satisfactorily. Features of acute peritonitis were seen in 6 patients and required exploratory laparotomy in 4. Non-Hodgkin's lymphoma of the stomach in one patient has regressed following a combination of reduction in immunosuppressive therapy and a course of chemotherapy. The development of hepatitis or severe liver dysfunction of unknown cause has been associated with significant morbidity and mortality. Since this study was undertaken, the incidence of gastrointestinal complications has been greatly reduced by modifications to our immunosuppressive and anti-infection prophylactic drug protocols. Nevertheless, such complications still occur and it is important that the gastroenterologist should understand the need for urgent and intensive investigation and therapy.

Female↗
PubMed1990

Improved cardiac allograft function following triiodothyronine therapy to both donor and recipient.

Brain death is associated with neuroendocrine changes, in particular with a significant reduction of plasma-free triiodothyronine (T3) that results in impaired aerobic metabolism. Myocardial energy stores are reduced and tissue lactate increased. Cardiac function deteriorates. Similar metabolic changes are seen in patients undergoing open-heart surgery on cardiopulmonary bypass, including those undergoing heart transplantation. Therapy with T3 leads to a reversal of these metabolic changes, resulting in improved cardiac function. One hundred and sixteen consecutive potential donors have been so treated, as have 70 of the recipients. Immediate posttransplant cardiac function was good in all but 3, and these hearts recovered to normal within a maximum of 24 hr of mechanical support. In 2 small randomized trials in patients undergoing myocardial revascularization on cardiopulmonary bypass, postoperative T3 therapy was associated with a reduced need for inotropic support and diuretic therapy in the first study and improved cardiac output in the second study.

Adenosine Triphosphate↗
PubMed1990

Experience with cardiorespiratory support devices in patients undergoing heart and heart-lung transplantation.

During the 2-year period 1987 through 1988, 124 patients were assessed for heart or heart-lung transplantation. Sixty were accepted for heart transplantation, of whom 49 received transplants. Nine required pretransplant intra-aortic balloon pump support (+/- positive-pressure ventilation) for periods ranging from 2 to 15 days (mean 5 days). One patient was supported successfully by a pneumatic biventricular assist device for 70 days pretransplant. The 30-day survival in this group of 10 critically unstable patients was 100% and the 6-month survival 90% (one death). This experience compares well with survival rates of 100% at 30 days and 92% at 6 months in the 39 patients who required no form of pretransplant circulatory support. The biventricular assist device also has been used in 2 other patients; one did not survive to transplant and the other was deemed unsuitable by virtue of cerebral injury. Extracorporeal membrane oxygenation supported 2 posttransplant patients (one heart and one heart-lung) with grossly impaired pulmonary function for periods of 5 and 2 days respectively, but both died before lung function had recovered.

Adult↗
PubMed1989

Time to first shock and clinical outcome in patients receiving an automatic implantable cardioverter-defibrillator.

The relation between time to first shock and clinical outcome was studied in 60 patients who received an automatic implantable cardioverter-defibrillator (AICD) from August 1983 through May 1988. The mean (+/- SD) patient age was 64 +/- 10 years, 82% were men and the mean ejection fraction was 33 +/- 13%. During follow-up, 38 patients (63%) had one or more shocks; there were no differences in age, gender distribution or ejection fraction at entry between the shock and no shock groups. Among 51 patients with coronary artery disease, 31 (61%) had one or more shocks, whereas all seven patients with cardiomyopathy had one or more shocks (p less than 0.05). Neither of the two patients with idiopathic ventricular fibrillation had shocks. Of the 13 deaths, 12 occurred during post-hospital follow-up and 1 during the index hospitalization. Of the four sudden post-hospital deaths, only one was due to tachyarrhythmia in the absence of acute myocardial infarction. All four sudden deaths and five of eight post-hospital nonsudden deaths occurred in patients who had had one or more appropriate shocks during follow-up. Eight of the nine first appropriate shocks among patients who subsequently died occurred within the first 3 months of follow-up, but the actual deaths were delayed to a mean of 14.1 +/- 13.9 months (p less than 0.05). The mean time to all deaths was 14.8 +/- 13.1 months. The ejection fraction was significantly lower among patients who died than among patients who survived (25 +/- 7% versus 35 +/- 14%, p less than 0.02), but it did not distinguish risk of first shocks.(ABSTRACT TRUNCATED AT 250 WORDS)

Actuarial Analysis↗
PubMed1989

Inotropic effect of triiodothyronine (T3) in low cardiac output following cardioplegic arrest and cardiopulmonary bypass: an initial experience in patients undergoing open heart surgery.

A significant reduction in plasma free triiodothyronine (T3) (P less than 0.0001) has been observed in patients undergoing open heart surgery. The beneficial effect of T3 would appear to be associated with increased synthesis and utilization of myocardial high energy stores. We have therefore administered T3 (4-10 micrograms iv) to 10 patients either when difficulty was being experienced in weaning from cardiopulmonary bypass (CPB) support (n = 5), or when myocardial function remained extremely poor (n = 5), despite inotropic and intraaortic balloon pump support. Mean preoperative NYHA functional class of the 10 patients was 3.2, left ventricular enddiastolic pressure (LVEDP) 20 mm Hg and ejection fraction (EF) 40%. The mean myocardial ischaemia time was 72 min (range 40-120 min). Within 1 h of T3 administration the mean plasma free T3 level had risen from 1.03 to 3.56 micrograms/ml and CPB was discontinued in all 5 cases. Balloon pump support (n = 2) was no longer essential within 3 h. At 1 h, the mean arterial pressure (MAP) had risen from 42 to 78 mm Hg, and heart rate (HR) from 90 to 104 beats/min; the left atrial pressure (LAP) had fallen from 30 to 14 mm Hg, and the central venous pressure (CVP) from 20 to 11 cm H2O. (All changes significant at P less than 0.0001.) Inotropic support had been significantly reduced or discontinued. To our knowledge, T3 has not been administered previously as an inotropic agent to patients who have undergone cardiac surgery. We believe that T3 may have an important role in the rescue of failing hearts following a period of myocardial ischaemia in patients who have undergone open heart surgery.

Cardiac Output, Low↗
PubMed1989

The role of ABO blood group compatibility in heart transplantation between closely related animal species. An experimental study using the vervet monkey to baboon cardiac xenograft model.

The role of ABO blood group compatibility on graft survival when transplantation is performed between closely related animal species is uncertain. Heart transplants (in the neck) were performed between donor vervet monkeys and recipient baboons; no immunosuppressive therapy was given. Survival in ABO-compatible pairs (group 1, n = 9) was for a mean of 10.3 (+/- 5.2) days, which was not significantly different from that in ABO-incompatible pairs (group 2, n = 9: mean survival 7.3 +/- 5.6 days). In group 2, however, three hearts were rejected hyperacutely within 60 minutes, whereas in group 1 only one heart was rejected within 24 hours (not significant). Preformed anti-vervet monkey antibody was present in only one of 18 baboons, but developed in eight others. ABO-specific antibodies were present in all nine group 2 baboons and increased in titer in six cases. Histopathologic features of vascular (humoral) rejection, sometimes associated with cellular infiltration, were seen in a majority of hearts in both groups. Though the number of animals in this study was small, ABO-incompatibility would not appear to be a major factor in cardiac xenograft survival when transplantation is performed between closely related primate species, though early hyperacute rejection would seem more likely to occur when blood group incompatibility is present.

ABO Blood-Group System↗
PubMed1989

Experience with endomyocardial biopsy in 23 patients with heart transplants.

In the 33-month period April 1985 to December 1987, endomyocardial biopsy was performed 314 times in 23 patients with orthotopic (21) or heterotopic (2) heart transplants at Baptist Medical Center. The technique is described. Adequate tissue was obtained in 99% of cases and there was only one complication from the procedure. Mild to severe acute rejection was seen in 105 specimens (33%). The histopathological interpretation has proved invaluable in the care of patients with heart transplants.

Biopsy↗