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Biomedical subjects

J G Copeland

Publications and source records attributed to J G Copeland.

At least 19 recordsLinked to original sources
PubMed1996

Heart-lung transplantation in situs inversus.

Reconstruction was accomplished in a 2 heart-lung recipients with situs inversus resulting in a left-sided systemic venous atrium. We created a large common atrium that was closed on the left side, leaving an atrial cuff on the inferior right quadrant. To this we anastomosed the donor right atrium, which had been opened laterally between the cavae. This resulted in some clockwise rotation of the ventricles and anterior positioning of the apex. The right pulmonary veins passed superior to the atrial anastomosis and posterior to the donor right atrium. Cardiopulmonary function was excellent in both cases.

Adolescent↗
PubMed1995

Left ventricular function after extended hypothermic preservation of the heart is dependent on functional coronary capillarity.

BACKGROUND: A growing body of knowledge has led to the hypothesis that injury to the microcirculation during hypothermic myocardial preservation may result in decreased contractility of hearts upon reperfusion. METHODS AND RESULTS: To test this hypothesis, we examined the relationship between no-reflow and left ventricular function after hypothermic cardiac preservation after reperfusion with solutions containing dilute whole blood (DWB) or washed red blood cells (K2RBC). Rat hearts were arrested with high-potassium cardioplegia, then flushed and stored for 6 hours in low-potassium cardioplegia at 4 degrees C. Hearts were reperfused at a constant flow rate (4 mL/min) with K2RBC for 60 minutes (group 1, n = 5) or DWB for 7 minutes followed by 53 minutes of K2RBC (group 2, n = 5). Left ventricular developed pressure (LVDP) was measured with an intraventricular balloon. Immediately after functional assessment, hearts were perfused with an india ink solution to mark flow, then glutaraldehyde. Morphometric techniques were used to determine the degree of capillary compression [delta d(c)], perfused capillary number per fiber area [QA(0)P], and perfused capillary surface area per fiber volume [Sv(c,f)P]. Capillaries were moderately compressed in both groups after reperfusion (group 1, 19 +/- 1%; group 2, 20 +/- 1%). QA(0)P and Sv(c,f)P were highly correlated with delta d(c) in hearts reperfused with K2RBC (r = .92 and r = .92; P < .01). Although statistically significant, the correlation was not as strong in DWB-reperfused hearts (r = .66 and r = .67; P < .05). LVDP was correlated to QA(0)P and Sv(c,f)P (r = .86 and r = .87, respectively) for groups 1 and 2. CONCLUSIONS: The weaker correlation between capillary perfusion and capillary compression in DWB-reperfused hearts suggests that factors other than compression contribute to no-reflow after hypothermic preservation. Regardless of the composition of the reperfusate, recovery of left ventricular function after hypothermic ischemia is directly related to coronary capillary perfusion upon reperfusion.

Animals↗
PubMed1995

Simplified technique of heart-lung transplantation.

Well-known complications of heart-lung transplantation include mediastinal bleeding and phrenic nerve injury. Conventional technique places the hila behind the phrenic nerves. We have placed the hila in front of the phrenic nerve in our last 10 patients, using direct caval anastomoses when feasible. This minimizes traction on and dissection around the phrenic nerves, and allows anterior rotation of the heart-lung block for easier hemostasis of the posterior mediastinum after implantation.

Dissection↗
PubMed1995

A technique to simplify and improve exposure in heart-lung transplantation.

Heart-lung transplantation is associated with high perioperative mortality rates. A modified operative technique was used by one surgeon operating on 17 patients at the University of Arizona, Tucson, and the Inland Northwest Thoracic Organ Transplant Program, Spokane, Washington. This technique gives greater exposure to the area of dissection behind the heart-lung block after implantation and makes maintaining hemostasis easier. No deaths from bleeding complications occurred and no reoperations for bleeding were required with this technique. The Kaplan-Meier survival was 82% at 1 year. This technique simplifies a difficult technical procedure and may reduce mortality rate.

Actuarial Analysis↗
PubMed1995

Early in reperfusion following myocardial ischemia, leukocyte activation is necessary for venular adhesion but not capillary retention.

OBJECTIVE: The pathobiology of leukocyte sequestration in the coronary microcirculation following ischemia is unclear. We examined the location(s) and persistence of leukocyte sequestration of unactivated and preactivated blood in the coronary microcirculation early during reperfusion following ischemia. METHODS: Isolated rat hearts were subjected to 30 min of 37 degrees C, no-flow ischemia. Hearts were initially reperfused with diluted whole blood containing fluorescent leukocytes (DWB*). At 5, 20, and 35 min of reperfusion (R), the deposition of leukocytes in the coronary capillaries and venules was observed directly using intravital fluorescence microscopy. Four groups were studied: a nonischemic control group (Gr I), and postischemic groups reperfused with DWB* treated with vehicle (Gr II) or preactivated with 10(-8) M N-formylmethionyl-leucyl-phenylalanine (fMLP) (Gr III) or 10(-6) M fMLP (Gr IV). RESULTS: At R5, postischemic reperfusion with unactivated blood caused a significant trapping of leukocytes in coronary capillaries (Gr I = 2.2 +/- 0.4 versus Gr II = 5.6 +/- 0.6 leukocytes per capillary field, P < 0.05). Hearts in Gr IV exhibited significantly greater leukocyte retention in capillaries compared to all other groups at R5 (R5, Gr IV = 8.8 leukocytes per capillary field, P < 0.05) and at R35. At R5, although more leukocytes were observed adhered to the venules in Gr II compared to Gr I, the difference was not statistically significant (Gr I = 1.7 +/- 0.7 versus Gr II = 3.4 +/- 0.5 leukocytes per 100 microns venule, P = 0.23). DWB* preactivated with the lower concentration of fMLP (10(-8) M) resulted in a significant increase in venular leukocyte adhesion at R5 compared to Gr I and Gr II (Gr III 6.1 +/- 0.5, P < 0.05). After 35 min of reperfusion, a greater percentage of leukocytes remained in the capillaries than in the venules. CONCLUSIONS: These direct observations suggest that early in reperfusion after ischemia, both leukocyte and endothelial activation are necessary for venular adhesion, but that ischemia-induced coronary microvascular alterations are sufficient to promote leukocyte retention in coronary capillaries. These results also indicate that during 35 min of reperfusion, the degree of leukocyte washout is greater in the venules than in the capillaries. These results suggest that the mechanisms contributing to leukocyte retention early in reperfusion following myocardial ischemia are, indeed, different in the capillaries and venules and that the mechanisms affecting retention in capillaries are more persistent than those in the venules.

Animals↗
PubMed1995

An international experience with the CarboMedics prosthetic heart valve.

A multi-center, international, prospective trial of the CarboMedics valve was initiated in September 1987. Twenty-five centers were included for the purpose of demonstrating the clinical effectiveness of this new rotatable bileaflet Pyrolite carbon prosthesis. The study included 1228 patients (1372 valves) enrolled between September 1987 and September 1993. There were 674 males and 554 females from ages two to 84 years. There were 603 aortic, 476 mitral and 144 double valve implants. Mean follow up time was 30.2 months; 96.3% of patients had completed documentation up to and including one year. Functional class was III or IV for 87.1% of patients preoperatively, and I or II in over 96% of patients for the first five post-operative years. Survival for the entire group was 89% (n = 902) at one year, 84% (n = 463) at three years, and 81% (n = 92) at five years. There were no significant survival differences between the aortic and mitral valve replacement groups. Statistically significant differences in survival (p < or = 0.1) for all patients (primary and non-primary) were found to be associated with female gender (p = .0097), increasing age (p = 0.0001), increasing preoperative NYHA classification (p = 0.0001), concomitant procedures performed during surgery (p = .0001), double valve replacement (p = 0.0622), and presence of preoperative endocarditis (p = .0829). Late deaths totaled 88 with 46 of those classified as valve-related. There was no valve failure.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

Frequency of left atrioventricular regurgitation postoperatively after repair of complete atrioventricular defect.

Experience with 43 consecutive cases of isolated (except for patent ductus) atrioventricular (AV) defects treated surgically at University Medical Center in Tucson, Arizona, were reviewed to determine occurrence and amount of postoperative left AV valve regurgitation. Patients initially evaluated at ages 1 day to 59 months were included, 32 of whom had Down's syndrome and 11 of whom had normal chromosomes. Age at repair ranged from 1 month to 171 months; 70% of patients had repair at < 16 months of age. Mean follow up was 7.1 years. Nine patients died, 8 of whom had Down's syndrome. Left AV valve regurgitation was absent or mild in 69% of patients who survived the perioperative period; however, very early repair (age < or = 4 months) was associated with significantly greater probability of moderate or severe left AV valve regurgitation than that seen in patients who had repair after that age. These data suggest that left AV valve regurgitation after repair of AV defects is usually not clinically significant, but patients in this series who underwent operation very early (age < or = 4 months) were at the highest risk for significant left AV valve regurgitation.

Adolescent↗
PubMed1994

Four-year experience with the CarboMedics valve: the North American experience. North American team of clinical investigators for the CarboMedics prosthetic heart valve.

A multicenter prospective trial of the CarboMedics valve was initiated in July 1988. Twelve North American centers were included for the purpose of establishing the safety and efficacy of this new rotatable, bileaflet, pyrolytic-Carbon prosthesis. The study included 786 patients (using 891 valves) enrolled between July 1988 and August 1992. There were 447 male and 339 female patients from ages 2 to 83 years. Of the 618 primary replacement operations (including double valves), 393 were aortic and 292 were mitral valve replacements. Mean follow-up time was 16.1 months; 94.7% of patients had completed documentation up to and including one year. New York Heart Association functional class was III or IV for 84.4% of patients preoperatively, and I and II in over 96% of patients for the first three postoperative years. Survival for the entire group was 93% (622) at 1 month, 89% (504) at 1 year, 87% (213) at 2 years, and 85% (41) at 3 years. There were no significant survival differences between primary and repeat replacements or between aortic, mitral, and double-valve replacements. Primary replacement patients with concomitant procedures (n = 241) had slightly decreased survival rates compared with those who underwent isolated procedures (isolated survival rate, 92% [98]; concomitant procedure survival rate, 81% [59] at 2 years; p = 0.002). There was no valve failure. Linearized rates (events per 100 patient-years) in primary replacement patients after 30 days included the following: thrombosis, 0.39; thromboembolism, 0.92; hemolysis, 0.53; anticoagulant-related hemorrhage, 2.36; paravalvular leak, 0.92; endocarditis, 0.53; reoperation, 0.92; and explantation, 0.66.(ABSTRACT TRUNCATED AT 250 WORDS)

Actuarial Analysis↗
PubMed1994

The effects of improved hemodynamics on aortic dimensions in patients undergoing heart transplantation.

PURPOSE: Retrospective studies have demonstrated an accelerated growth rate of abdominal aortic aneurysms in heart transplant patients. This prospective study was undertaken to define the relationship between cardiac hemodynamics and posttransplant aortic dilation. METHODS: Sixty-eight patients undergoing heart (n = 60) or heart-lung (n = 8) transplantation were prospectively evaluated with abdominal ultrasonography before transplantation and annually after transplantation. Risk factors implicated in aneurysm growth, including age, indication for transplantation, immunosuppression, posttransplantation hypertension, and abdominal aortic dimension before transplantation were recorded. All patients underwent annual coronary artery catheterization and multiple gated acquisition scanning. RESULTS: Thirty-seven patients (54%) had no change in aortic diameter after transplantation (pretransplantation and posttransplantation diameter = 1.8 +/- 0.3 cm), over a mean follow-up period of 28 +/- 14 months. In the remaining 31 (46%) patients, aortic diameter increased by 0.5 +/- 0.6 cm over 31 +/- 15 months (p < 0.05). Four (6%) of these 31 patients had abdominal aortic aneurysms (mean aortic diameter = 5.0 +/- 0.8 cm). The mean increase in aortic diameter among these 4 patients was 1.8 +/- 0.2 cm (annual rate of growth = 0.96 +/- 0.3 cm/year). Patients experiencing an increase in aortic dimension after transplantation had significantly lower (p < 0.005) pretransplantation ejection fractions (17.1% +/- 10.5% vs 28.6% +/- 18.1%) and, as a consequence, significantly greater (p < 0.05) increases in their ejection fractions after transplantation compared with patients with stable aortic dimensions (42.7% +/- 12.6% vs 31.8% +/- 18.0%). CONCLUSIONS: Of 68 heart transplant patients prospectively evaluated, aortic diameter increased in 31 (46%); new aneurysms developed in four of these patients. Greater incremental increases in cardiac ejection fraction were significant correlates with aortic enlargement.

Adult↗
PubMed1994

Microvascular compression during myocardial ischemia: mechanistic basis for no-reflow phenomenon.

Alterations in fiber size and capillary diameter were highly correlated with perfusion deficits after myocardial ischemia. After 5 (n = 3) and 30 (n = 5) min of global normothermic ischemia, isolated rabbit hearts were perfused with India ink and then with glutaraldehyde. Morphometric techniques were used to determine mean fiber cross-sectional area [a(f)], mean effective capillary diameter [d(c)], total and perfused capillary number per fiber area, and capillary length per fiber volume in subepicardium (Epi) and subendocardium (Endo). Sarcomere length was measured to differentiate between effects of fiber shortening and intracellular edema on a(f). After 30 min of ischemia, a(f) increased 41 (Epi) and 36% (Endo). Of these percentages, fiber shortening accounted for 2 (Epi) and 25% (Endo). Decreased d(c) was correlated with increased a(f) as well as reductions in perfused capillary number and length. Whereas intracellular edema had the greatest overall effect on a(f), fiber shortening accounted for a significant increase of a(f) in Endo, where perfusion deficits were most pronounced. These data support the hypothesis that microvascular compression consequent to increased a(f) contributes to perfusion deficits after myocardial ischemia.

Animals↗
PubMed1993

New technique for improving hemostasis in aortic root replacement with composite graft.

By using both aortic annular and supraannular aortic wall tandem suture lines, we have, in our experience, markedly improved hemostasis in aortic root replacement with composite conduits of two types. Using this technique, 4 of 5 patients required 2 units or less of transfused red blood cells. Two patients did not receive transfusions. The technique consists of using interrupted mattress sutures to anchor the lower part of the valve sewing ring to the aortic annulus. The upper part of the sewing ring is then anchored with a running suture line to the cut edge of the supraannular aortic wall.

Adolescent↗
PubMed1993

Incidence and recurrence of gastrointestinal cytomegalovirus infection in heart transplantation.

Cytomegalovirus (CMV) infection of the upper gastrointestinal tract is a major cause of morbidity in heart transplant recipients. Since April 1985, 201 patients underwent heart transplantation at our institution. Immunosuppressive therapy was with a triple drug regimen of cyclosporin A, prednisone, and azathioprine. Fifty-three of these patients had upper gastrointestinal symptoms, which primarily consisted of abdominal pain or nausea and vomiting despite prophylactic treatment with antacids, H2 blockers, or both. A total of 79 esophagogastroduodenoscopies were performed in this group; 15 patients required more than one esophagogastroduodenoscopy for recurrent symptoms. Of these 53 patients with persistent gastrointestinal symptoms, 16 (30.2%) had diffuse erythema or ulceration of the gastric mucosa (14), esophagus (1), and duodenum (1) with biopsy results that were positive for CMV on viral cultures (incidence, 8%). All patients with positive biopsy results were treated with intravenous ganciclovir at a dose of 10 mg.kg-1.day-1 in two divided doses for a period of 2 weeks. Recurrence developed in 6 patients (37.5%) and necessitated repeated therapy with ganciclovir. None of the 16 patients died as a result of gastrointestinal CMV infection. Patients who were seronegative for CMV and received a seropositive heart experienced earlier clinical manifestation of CMV infection. Infection of the upper gastrointestinal tract with CMV is a major cause of morbidity in cardiac transplant patients that may progress to a life-threatening complication if left untreated. Early diagnosis with esophagogastroduodenoscopy and biopsy for viral cultures is essential for documentation and proper management.

Adult↗
PubMed1993

Use of the Symbion biventricular assist device in bridging to transplantation.

From 1988 to 1991 13 patients received Symbion biventricular assist devices in attempts to bridge them to cardiac transplantation. All 7 of those who had cardiac transplants survived to hospital discharge. One death occurred 60 days after transplantation because of rejection. All other patients who received transplants are surviving. Implant times in this group varied from 10 to 164 days (mean, 55 days). There were two embolic neurologic events and two significant infections, and 2 of the survivors were dialyzed for reversible renal failure before transplantation. Of those who died on device support, 3 presented on centrifugal pump support. The three other deaths were caused by graft rejection, multiple organ failure, and multiple peripheral emboli. Biventricular assist devices optimally provide cardiac outputs of 4 to 5 L/min, can be quickly inserted often without requiring cardiopulmonary bypass, are easily explanted, and seem best suited for patients weighing less than 80 kg.

Adult↗