Biomedical subjects

R C Daly

Publications and source records attributed to R C Daly.

86 records · Page 5Linked to original sources

PubMed1992

Ischemia of the interventricular septum. A mechanism of right ventricular failure during mechanical left ventricular assist.

Right ventricular failure has been noted in up to 25% of patients requiring a left ventricular assist device. Altered septal motion or function is one proposed mechanism of right ventricular failure during left heart bypass. We studied the effect of regional ischemia and reperfusion of the interventricular septum on right ventricular function during complete left heart bypass. In six calves the septal perforating branches of the proximal left anterior descending coronary artery were isolated for intermittent occlusion. Complete left heart bypass was established with a Pierce-Donachy left ventricular assist device. Right and left ventricular function were studied with two-dimensional echocardiography and with intraventricular pressure monitors. Establishment of left heart bypass did not significantly affect right ventricular developed pressure, right ventricular end-diastolic area, or right ventricular fractional change in area. Left heart bypass significantly (p less than 0.001) decreased percent systolic septal wall thickening. Septal ischemia during left heart bypass resulted in a decrease in right ventricular developed pressure (p = 0.09), significant increase in right ventricular end-diastolic area (p = 0.002) and significant decrease in right ventricular fractional change in area (p less than 0.001), and a further decrease in interventricular septal wall thickening (p = 0.016). The interventricular septum became thin with flattening of its normal contour. Septal reperfusion resulted in right ventricular recovery with significant improvement in all factors (p less than 0.02). Similar results were documented during a second episode of septal ischemia with recovery after septal reperfusion. In some cases, septal ischemia may be an important factor in the development of right ventricular failure during left heart bypass.

Animals↗

PubMed1991

Bronchoalveolar carcinoma: factors affecting survival.

One hundred thirty-four consecutive patients (65 men and 69 women) underwent pulmonary resection for bronchoalveolar carcinoma. Mean age was 65 years. Lobectomy was done in 100 patients, pneumonectomy in 10, segmentectomy in 5, and wedge excision in 19. Only 10 patients had lymph node metastases (7.5%). The neoplasm was solitary in 111 patients (82.8%); 97 were in stage I, 4 were in stage II, 9 were in stage IIIa, and 1 was in stage IIIb. There were two operative deaths (1.5%). Thirty-nine complications occurred in 31 patients. Median follow-up was 5.1 years. Recurrent bronchoalveolar carcinoma developed in 45 patients. Five- and 10-year survival for patients in stage I was 75.2% and 62.0%, respectively. Survival for patients with T1 N0 M0 neoplasms was identical to expected survival and was 90.5% at 5 years, as compared with 55.4% for patients with T2 N0 M0 disease, only 35.9% for patients with multiple bilateral disease, and 0.0% for patients with bilateral disease (p less than 0.0001). Other significant factors adversely affecting survival included the presence of signs and symptoms, diffuse malignant invasion, mucin-producing tumors, and the histological absence of scar. We conclude that bronchoalveolar carcinoma has a unique natural history that is more influenced by local neoplastic processes than by lymph node metastases. Early aggressive pulmonary resection is safe and offers the potential for cure. The presence of bilateral cancer, however, is ominous.

Adenocarcinoma↗

PubMed1991

Long-term results of aortic valve replacement with nonviable homografts.

Between 1965 and 1972, 250 patients (186 men and 64 women; median age, 48 years) underwent aortic valve replacement with homografts preserved with beta-propiolactone (98 patients) or irradiation (152 patients); operative mortality was 6% (15 patients). Follow-up to death, reoperation, or recent evaluation was completed in 95% of patients, and median follow-up time was 11.4 years. Thromboembolic events occurred in two patients (0.21 events/100 patients/yr). Risk of reoperation was 22% at 5 years, 62% at 10 years, 85% at 15 years, and 95% at 20 years. Factors associated with increased risk of reoperation were young age, male sex, native aortic valve insufficiency, previous aortic valve surgery, history of endocarditis, and larger homograft size. Survival at 5, 10, 15, and 20 years was 85%, 66%, 53%, and 38%, respectively. Late survival was diminished in older patients and those with native aortic valve insufficiency and coronary artery disease. Aortic valve replacement with nonviable homografts has a high risk of late tissue degeneration and need for reoperation. However, the incidence of thromboemboli is minimal, and grafts can be replaced with low risk (4.5%) so that overall patient survival is similar to that observed with other bioprosthetic or mechanical heart valves.

Actuarial Analysis↗

PubMed1988

Histologic comparison of experimental coronary artery bypass grafts. Similarity of in situ and free internal mammary artery grafts.

This study compares patency and histologic structure of in situ internal mammary artery grafts, free internal mammary artery grafts, stripped, free internal mammary artery grafts, and stripped, free superficial femoral artery grafts (a muscular artery model) in a canine model of coronary artery bypass. Twenty-four adult mongrel dogs underwent bypass of the circumflex coronary artery with one of the above grafts. Three months postoperatively, graft patency was assessed by angiogram, and postmortem specimens were studied by intraluminal injection of a dilute barium solution proximal to the graft. Proximal, mid, and distal segments of each graft were examined microscopically. In situ internal mammary artery grafts and free internal mammary artery grafts were not significantly different in regard to patency, vascular wall cellular structure, or perfusion of the vasa vasorum. The stripped, free internal mammary artery group had a higher incidence of thrombosis, intimal thickening, and medial injury than the pedicled (in situ and free internal mammary artery) grafts. This difference may be due to early vascular wall ischemia as a result of poor early perfusion of the vasa vasorum. The stripped, free superficial femoral artery grafts were all patent, but all had adventitial injury.

Angiography↗

PubMed1986

Selective management of blunt splenic trauma.

During a recent 8-year period, 235 patients with documented blunt splenic trauma were treated. After exclusion of 39 patients with early deaths (19 dead on arrival, nine died in emergency room, and 11 died in operating room), the 196 remaining patients were treated in accordance with an evolving selective management program. Definitive management included splenectomy in 117 patients (59.7%), repair in 32 (16.3%), and nonoperative treatment in 47 (24%). A spectrum of blunt splenic trauma, as manifested by the degree of associated injuries (Injury Severity Scores), hemodynamic status, and blood transfusion requirements, was identified and permitted application of a rational selective management program that proved safe and effective for all age groups. Comparative analysis of the three methods of treatment demonstrated differences that were more a reflection of the overall magnitude of total bodily injury sustained rather than the specific manner in which any injured spleen was managed. Retrospective analysis of 19 nonoperative management failures enabled establishment of the following selection criteria for nonoperative management: absolute hemodynamic stability; minimal or lack of peritoneal findings; and maximal transfusion requirement of 2 units for the splenic injury. With operative management, splenorrhaphy is preferred, but it was often precluded by associated life-threatening injuries or by technical limitations. Of 42 attempted splenic repairs, ten (24%) were abandoned intraoperatively. There were no late failures of repair. In many cases of blunt splenic trauma, splenectomy still remains the most appropriate course of action.

Adolescent↗

PubMed1986

Pulmonary aspergilloma. Results of surgical treatment.

Between 1953 and 1984, 53 patients (40 male and 13 female) underwent thoracotomy for treatment of pulmonary aspergilloma. The median age was 58 years (range 4 to 86 years). Either underlying lung disease or immunologic risk factors were present in 49 patients (92%). Twenty-one patients (31%) had simple aspergilloma and 32 (47%) had complex aspergilloma. The most common indication for operation was an indeterminate mass, hemoptysis, or severe cough. Lobectomy, wedge excision, and pneumonectomy were the most frequent operations. Complications occurred in 78% of patients with complex aspergilloma and in 33% of patients with simple aspergilloma (p = 0.002). Operative mortality was 5% (one death) in patients with simple aspergilloma and 34% (11 deaths) in patients with complex aspergilloma (p = 0.01). Cause of death was respiratory failure in four patients, underlying pulmonary disease in three, aspergillosis in two, and other conditions in three. At follow-up, 84% of operative survivors with simple aspergilloma were alive and well compared with 43% of those with complex aspergilloma. Although operative mortality in patients with complex aspergilloma was high, 67% of the survivors had a good long-term result in terms of absence of symptoms, but they frequently died of underlying disease. In contrast, operation in patients with simple aspergilloma was done with low risk, and approximately 90% of survivors had a good late result. Late appearance of contralateral disease did occur and argues for rigorous postoperative surveillance.

Adolescent↗

PubMed1985

The risk of percutaneous chest tube thoracostomy for blunt thoracic trauma.

Analysis of 164 percutaneous chest tube thoracostomies performed as a standardized technical procedure in the management of 129 blunt trauma victims demonstrated an overall complication rate of 9.1% (15 of 164). Three complications (1.8%) were related to problems of insertion, and four (2.4%) represented the problem of pneumothorax after chest tube removal. The remaining eight complications (4.9%) were associated with positive bacterial cultures, two (1.2%) of which represented clinical empyema. Both cases of empyema had either prolonged chest tube placement (23 and 15 days) or multiple chest tubes (two and three) on the same side. Percutaneous chest tube thoracostomy remains an important facet in the management of certain types of blunt thoracic trauma. Associated risks can best be minimized with adherence to a standardized technique and management protocol.

Adolescent↗

PubMed1982

Penetration of cefazolin into normal and osteomyelitic canine cortical bone.

The ability of cefazolin to cross the capillary membrane and its concentrations in the interstitial fluid spaces were studied in normal and osteomyelitic canine bone. The maximum extraction after a single capillary passage and the net extraction after 3 min, determined with triple-tracer indicator-dilution techniques, demonstrated that cefazolin readily traversed the capillaries of normal and osteomyelitic bone. These studies suggest that the altered pathophysiology of osteomyelitic tissue and the complex diffusional characteristics of cefazolin enhanced the ability of this agent to cross the endothelial cells lining the capillaries of osteomyelitic bone. Volume of distribution studies demonstrated that cefazolin was distributed in the plasma and interstitial fluid spaces of normal cortical bone. Although these spaces were increased 330 and 941% in osteomyelitic tissue, the distribution of cefazolin increased proportionally. There was a direct correlation between the calculated concentrations of cefazolin in the interstitial fluid spaces of normal and osteomyelitic cortical bone and the simultaneous serum levels in animals in which a steady-state equilibrium had been achieved. These studies suggest that a physiological barrier or concentration gradient for cefazolin does not exist in normal or osteomyelitic bone. Cefazolin can cross the capillary membranes of bone and achieve bactericidal concentrations in the interstitial fluid space of normal and osteomyelitic tissue.

Animals↗

PubMedDate not supplied

Survival outcomes of patients with giant cell myocarditis bridged by ventricular assist devices.

Giant cell myocarditis is a highly lethal disorder characterized by rapidly progressive congestive heart failure. The aim of this study was to describe the clinical course of patients with giant cell myocarditis who received a ventricular assist device. Patients with giant cell myocarditis were identified from the Multicenter Giant cell Myocarditis Registry. Bridging to cardiac transplantation in the giant cell myocarditis patients who received a ventricular assist device was compared with bridging in the general population of heart failure patients, as reported in the literature. Median posttransplantation survival for patients with giant cell myocarditis who received and did not receive ventricular assist devices was calculated by the Kaplan-Meier method and compared with use of the log-rank test. Nine patients with giant cell myocarditis who received ventricular assist devices were identified. Seven patients survived to transplantation, four were alive 30 days posttransplantation, and two survived to 1 year. The rate of successful bridging to transplantation in seven of nine patients (78%) is similar to that reported for other ventricular assist device recipients. Posttransplantation survival of 57% (4 of 7) at 30 days and 29% (2 of 7) at 1 year was significantly lower compared with 93% 1-year survival of the 30 patients with giant cell myocarditis who did not receive ventricular assist devices before transplantation (p<0.001). Ventricular assist devices can be an effective bridge to transplantation for patients with heart failure caused by giant cell myocarditis. Although their posttransplantation survival was poor in our series, a few patients had long-term survival.

Adolescent↗

PubMedDate not supplied

Increased incidence of chronotropic incompetence in older donor hearts.

BACKGROUND: Previous Registry studies have reported that heart transplantation with older donor hearts is associated with a more than twofold increase in early mortality. METHODS: An analysis of 77 consecutive patients undergoing heart transplantations at our institution between June 1988 and July 1994 was performed to assess the effect of donor age on mortality and morbidity. Recipients were grouped into those receiving hearts from younger donors (aged < 40 years, n = 60) and those receiving hearts from older donors (aged > 40 years, n = 17). RESULTS: There were two deaths within the first 30 days in the younger donor group and no deaths in the other group. One-year survival rate was 95% and 100% for the "younger" and "older" groups, respectively. The mean recipient age of the younger donor group was lower (46 +/- 14 years) compared with the older donor group (57 +/- 7 years). Morbidity was compared between the two groups; the length of hospital stay (22.6 +/- 15.8 days versus 21.3 +/- 9.4 days), the graft ejection fraction at 1 week (64% +/- 5% versus 62% +/- 7%), and the mean number of rejection episodes within the first 3 months (0.79 versus 0.65) were not statistically different between the two groups. However, the incidence of chronotropic incompetence requiring permanent pacemaker implantation was significantly greater in the group who received older donor hearts (41.2% versus 10.3%, p < 0.05), independent of the ischemic time. CONCLUSIONS: This study shows that older donor hearts may be used safely in selected patients with excellent outcome, although there is an increased incidence of chronotropic incompetence requiring implantation of permanent pacemakers.

Adolescent↗

PubMedDate not supplied

Reduced work of breathing after single lung transplantation for emphysema.

BACKGROUND: Pulmonary emphysema, with or without chronic bronchitis, has emerged as the most common indication for successful single lung transplantation. Although gas exchange can be expected to improve after successful transplantation, such changes do not adequately explain the improvement in dyspnea experienced by these patients and resulting in improved quality of life. METHODS: We prospectively studied the respiratory mechanics of 14 single lung transplantation recipients with pulmonary emphysema, of whom 10 have been followed up beyond 1 year. The mean age of the group was 48.8 years (range, 42 to 60 years) for the seven men and seven women. Average donor-predicted total lung capacity was 0.6 L (+0.2 [standard error]) greater than recipient-predicted total lung capacity. Comparison of pulmonary resistance, dynamic lung compliance, and static lung compliance were taken to examine the possible role of reduced airways resistance and of improved elastic recoil in the reduced work of breathing. Results were analyzed by means of a one-tailed paired Student t test and linear regression analysis (both stepwise and multivariate); results are tabulated by mean (+/- 1 [standard error]). RESULTS: Between preoperative measurements and 12 months postoperatively, maximum lung elastic recoil increased from 8.1 (+/- 0.7) to 11.3 (+/- 1.0) cm H2O, p < 0.01; pulmonary resistance fell from 8.3 (+/- 0.8) to 5.4 (+/- 0.7) cm H2O sec/L, p < 0.01. Dynamic lung compliance fell from 0.23 (+/- 0.04) to 0.12 (+/- 0.02) L/cm H2O, p < 0.02, and static lung compliance fell from 0.66 (+/- 0.13) to 0.22 (+/- 0.05) L/cm H2O, p < 0.001. CONCLUSIONS: The decline in lung compliance after single lung transplantation reflects the importance of improvement in elastic recoil and reduced chest wall distention, improving the work of breathing. The 67% decline in static lung compliance (300% increase in elastic recoil) is probably the single most important mechanical factor leading to reduced dyspnea after single lung transplantation for emphysema.

Airway Resistance↗

PubMedDate not supplied

Pretransplantation seronegative Epstein-Barr virus status is the primary risk factor for posttransplantation lymphoproliferative disorder in adult heart, lung, and other solid organ transplantations.

BACKGROUND: The relative importance and interrelationship of risk factors for posttransplantation lymphoproliferative disorder are poorly understood. METHODS: The prospective pretransplantation serologic testing for Epstein-Barr virus of all nonrenal solid organ transplant recipients at our institution made it possible to assess the relative risk for posttransplantation lymphoproliferative disorder in seropositive and seronegative recipients. RESULTS: Fourteen cases of lymphoproliferative disorder were identified in the first 389 consecutive transplant recipients (288 liver, 44 heart, 20 lung, 37 kidney-pancreas) undergoing transplantation from 1985 to 1992 (mean follow-up 33 months). The incidence rates of lymphoproliferative disorder (per 100 person-years) during the first 2 years after transplantation (a period in which all cases occurred) were 1.4 for liver, 2.0 for heart, 6.2 for lung, and 5.2 for kidney-pancreas transplant recipients and were significantly different between liver and lung (p = 0.005) and liver and kidney-pancreas (p = 0.002) groups. Of 367 seropositive patients, lymphoproliferative disorder developed in only three. The incidence rate ratios between seronegative and seropositive recipients were as follows: 76 ([95% confidence interval; 46, 144], p = 0.0000) for any form of lymphoproliferative disorder and 145 ([60, 347], p = 0.0000) for fatal or brain forms. The incidence rate of lymphoproliferative disorder was significantly higher for seronegative recipients who required antilymphocyte antibody therapy for rejection than for those who received none. CONCLUSIONS: The high intrinsic risk for lymphoproliferative disorder in the Epstein-Barr virus seronegative patient, which is amplified by higher levels of immunosuppression, may, in some instances, preclude transplantation.

Acyclovir↗

PubMedDate not supplied

Methylergonovine-induced diffuse coronary spasm in a patient with exercise-induced coronary spasm after heart transplantation.

Coronary artery spasm is a rarely reported condition after heart transplantation. We report a case of exercise-induced coronary artery spasm in a patient 1-year after orthotopic heart transplantation. Serial quantitative coronary angiography showed significant diffuse loss of luminal diameter. Provocative testing with intracoronary acetylcholine and intravenous methylergonovine maleate was performed in an effort to document efficacy of the antispasm regimen. Infusion of acetylcholine into the left anterior descending coronary artery resulted in transient closure of the vessel. Diffuse spasm resulting in hypotension and ventricular fibrillation occurred with intravenous methylergonovine maleate administration. Because of the risk of provoking diffuse spasm, intravenous administration of methylergonovine maleate should be avoided in the posttransplantation setting. Review of the literature suggests that coronary artery spasm after transplantation is often associated with severe transplant coronary artery disease and may be associated with a poor prognosis. Coronary artery spasm may be a more common cause of syncope and death after transplantation than it is currently thought to be.

Acetylcholine↗

PubMedDate not supplied

Cyclosporine does not affect in vitro bronchial smooth muscle contractions in treated Lewis rats.

The purpose of this study was to investigate whether cyclosporine treatment could modify airway responses, thus playing a role in bronchial hyperresponsiveness observed in patients after lung transplantation. We have studied the effect of cyclosporine treatment in rats on subsequent bronchial responses to electrical field stimulation, to exogeneous 5-hydroxytryptamine, and acetylcholine in organ baths. The isometric force of contraction of bronchial smooth muscle was measured. Voltage and frequency responses produced by electrical field stimulation were similar in control and in rat bronchi treated with cyclosporine. Concentration-response curves to exogeneous acetylcholine were superimposed for both groups of animals, as were those to 5-hydroxytryptamine. Our results show that cyclosporine treatment does not affect bronchial smooth muscle contraction and rule out possible contribution of cyclosporine to the bronchial hyperresponsiveness described after lung transplantation.

Acetylcholine↗