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Biomedical subjects

M S Sweeney

Publications and source records attributed to M S Sweeney.

At least 19 recordsLinked to original sources
PubMed1999

The Hemopump in 1997: a clinical, political, and marketing evolution.

BACKGROUND: The Hemopump (Medtronic, Inc, Minneapolis, MN) was conceived in 1975 and designed in 1982 as a temporary, extracorporeal cardiac assist system. Although it has been used clinically in Europe, it is not currently available in the United States. METHODS: In vitro and in vivo testing of the Hemopump began in 1983. Clinical investigations have included studies of patients in cardiogenic shock, Hemopump-supported coronary artery bypass operations in Sweden, and European studies of percutaneous transluminal coronary angioplasty (PTCA) with Hemopump support. RESULTS: The Hemopump has demonstrated positive hemodynamic effects in patients. Laboratory and clinical studies have shown that the nonpulsatile axial flow generates flows of up to 4.5 L/min while maintaining adequate perfusion of other organs. In Europe, hemopumps have been used successfully to support coronary bypass and PTCA. CONCLUSIONS: The Hemopump system is simple, inexpensive, and well tolerated by the blood elements. Moreover, its design allows flexibility in supporting patients during cardiopulmonary bypass (in lieu of conventional techniques) and high risk angioplasty, as well as in rescuing patients with low cardiac output.

Angioplasty, Balloon, Coronary↗
PubMed1997

Traumatic aortic transections: eight-year experience with the "clamp-sew" technique.

BACKGROUND: Because traumatic aortic transection is associated with high mortality rates, great debate exists about the appropriate operative technique for treatment of patients who have acute traumatic aortic transection. METHODS: To determine the safety and efficacy of the "clamp-sew" method, we retrospectively reviewed our 8-year experience treating 75 patients who had aortic injuries secondary to blunt trauma. Seventy-one of these patients were treated surgically. The clamp-sew method was used in all of these operations. RESULTS: Aortic cross-clamp time averaged 24 minutes (range, 14 to 36 minutes), with 4/71 having times in excess of 30 minutes. One patient (clamp time, 28 minutes) became paraplegic. Significant associated injuries were seen in 51/75 patients (48/71 patients with operation), including intrathoracic (35 patients), orthopedic (28 patients), intraabdominal (24 patients), and central nervous system (17 patients) damage. No patient died within 24 hours of operation. Overall 30-day mortality was 12% (9/75), with 7/9 having two or more aforementioned associated injuries. Of these 7, 5 had central nervous system injuries. Two of 9 died within 30 days without two or more associated injuries: 1 Jehovah's Witness of low hemoglobin, and 1 patient of sepsis. CONCLUSIONS: Although any of several maneuvers may be appropriate in managing traumatic aortic injuries, the simple "clamp-sew" technique is a safe and effective method for the treatment of traumatic aortic transections.

Adolescent↗
PubMed1995

Diffuse vasospasm following stenting of a free gastroepiploic artery graft: resolution with balloon angioplasty and intensive medical therapy.

Vasospasm following balloon angioplasty of gastroepiploic artery bypass grafts can be prevented or reversed with vasodilators. In our patient, stent deployment for ostial stenosis of a free gastroepiploic artery graft was accompanied by severe, diffuse spasm and a change in graft configuration that required both intensive medical therapy and balloon angioplasty for resolution.

Angioplasty, Balloon, Coronary↗
PubMed1993

Improved multiorgan function after prolonged univentricular support.

Eleven cardiac transplant candidates (all male; mean age, 43.3 years) with multiorgan (hepatic, pulmonary, and/or renal) dysfunction were sustained for prolonged periods (> 30 days) with the HeartMate (Thermo Cardiosystems, Inc, Woburn, MA) left ventricular assist device. We evaluated the effect of extended support on end-organ recovery and on the ultimate outcome of cardiac transplantation. In addition to cardiac failure, 9 patients had hepatic dysfunction, 8 had pulmonary dysfunction, and 6 had renal dysfunction (4 of whom required hemodialysis before left ventricular assist device support). Mean duration of support was 115 days (range, 31 to 233 days). All patients underwent successful transplantation; 10 of these patients survived a mean of 24 months. One patient, who had required hemodialysis and ventilatory support during and after support, experienced progressive multiorgan failure and died 7 weeks after transplantation. Two late deaths after transplantation were unrelated to the device. Overall, patients experienced improvement in cardiac functional class status, and most participated in cardiac rehabilitation programs before transplantation. During left ventricular assist device support, hepatic function returned to normal in 8 patients, pulmonary function recovered in 7, and renal function returned to normal in 4. One patient who required hemodialysis underwent renal transplantation after cardiac transplantation and had complete recovery of renal function. In the current era of donor shortages, gravely ill patients can benefit from a strategy of prolonged left ventricular assist device support. This strategy has proved safe, has allowed for reversal of multiorgan dysfunction, and has produced healthier transplant candidates.

Adult↗
PubMed1992

Device-supported myocardial revascularization: safe help for sick hearts.

Although advances in both the technology of artificial oxygenation and our understanding of myocardial preservation have made aortocoronary bypass operations safer, clinical settings remain where even these improvements have limited efficacy. We have recently treated 43 severely ill patients with aortocoronary bypass, using a ventricular assist device for intraoperative hemodynamic support and ventricular decompression. For 34 of the patients, preoperative ejection fractions (multigated acquisition) ranged from 0.12 to 0.28 (average, 0.22); 6 patients manifested cardiogenic shock preoperatively, and emergency operations precluded multigated acquisition studies. Twenty-nine patients had preoperative evidence of congestive heart failure, 10 had a prior bypass operation, 9 had major chronic obstructive pulmonary disease, and 2 were Jehovah's Witnesses. The operative technique involved minimal doses of heparin (1 to 1.5 mg/kg), no cardioplegia, and no cardiopulmonary bypass. Revascularization was accomplished on beating, nonworking hearts, with right (40 of 43) and left (43 of 43) ventricles supported by Nimbus Hemopumps (4 of 43) or Bio-Medicus centrifugal ventricular assist devices for an average of 112 minutes. In each case, the patient's lungs were used as the oxygenator. An average of 3.7 bypass grafts per patient were constructed. The left internal mammary artery was used in 41 patients, whereas at least one coronary endarterectomy was required in 20. Six patients had concomitant placement of an automatic implantable cardioverter defibrillator. Two patients (4.6%) died: 1 (with preoperative cardiogenic shock) of low cardiac output on postoperative day 1, and 1 of a severe neurologic deficit on day 8. Follow-up ranged from 2 to 18 months (average, 8.9 months), with all survivors demonstrating improvement in cardiac function in both the early and late postoperative periods.(ABSTRACT TRUNCATED AT 250 WORDS)

Comorbidity↗
PubMed1991

Primary cardiac sarcomas.

In marked contrast to benign cardiac tumors, primary cardiac sarcomas occur infrequently. Moreover, there is no uniform approach to treating such patients, and the benefits of postoperative chemotherapy are unclear. Between 1964 and 1989, 21 patients with primary cardiac sarcomas underwent surgical resection alone (n = 7), chemotherapy alone (n = 1), or combined operation and postoperative chemotherapy based on adriamycin (n = 13). Twenty-four operations were performed on 20 patients with relief of symptoms in all. Eleven patients had complete resection. Operative mortality was 8.3% (2/24). Histology and originating chamber(s) included angiosarcoma (n = 7; 6/7 in right atrium, 1 in left atrium), malignant fibrous histocytoma (7; all in left atrium), fibrosarcoma (2; 2/2 in left atrium), rhabdomyosarcoma (2; 1 in left atrium, 1 in right ventricle), leiomyosarcoma (2; 1 in left atrium, 1 in left ventricle); and one undifferentiated sarcoma (right atrium). Overall actuarial survival was 14% at 24 months after resection. Patients with complete resection had a median survival of 24 months compared with only 10 months in all other patients (p = 0.035). Postoperative chemotherapy did not enhance survival in patients with incomplete resection. At this time, aggressive and complete surgical resection seems to offer the best hope for palliation and survival in an otherwise fatal disease.

Adolescent↗
PubMed1991

Cardiac transplantation in Puerto Rican patients at the Texas Heart Institute.

Cardiac transplantation is the treatment of choice for patients suffering from end-stage cardiac disease unamenable to conventional medical or surgical treatment. More than 390 patients have undergone heart transplantation at the Texas Heart Institute in Houston, and nine were Puerto Rican. Overall survival of these patients is 88%. Our experience with patients from Puerto Rico is described.

Age Factors↗
PubMed1990

Heart transplantation in Jehovah's Witnesses. An initial experience and follow-up.

More than 25 years of experience performing heart surgery on Jehovah's Witnesses has culminated in successful cardiac transplantation without administering blood products in five patients (mean age, 44.4 +/- 8.3 years) of this faith. The use of blood-conserving methods, iron supplementation, bone marrow-sparing maintenance immunotherapy, and brisk postoperative diuresis has added to the efficacy of cardiac transplantation in these patients. No perioperative deaths occurred, and early follow-up studies have shown that these patients have not been more susceptible to higher graft rejection rates due to the lack of pretransplant blood transfusions. As more Jehovah's Witnesses undergo heart transplantation in the future, comparison with other recipients who allow pretransplant blood transfusions may lead to a better understanding of rejection immunobiology. We conclude that cardiac transplants may be safely offered to Jehovah's Witnesses without fear of a uniformly poor outcome.

Adult↗
PubMed1990

Extension of donor criteria in cardiac transplantation: surgical risk versus supply-side economics.

To combat the continuing shortage of ideal donor hearts, we have used cardiac allografts from high-risk donors for critically ill recipients. We defined high-risk donor variables as age greater than 40 years, systemic (noncardiac) infection, cardiopulmonary resuscitation greater than 3 minutes, ischemic time longer than 5 hours, weight more than 20% less than that of the recipient, and requirements for high doses of inotropes. Of the 305 donors we have used, 73 (23.9%) have been high-risk, with 59/73 (80.8%) exhibiting one variable, 12/73 (16.4%) exhibiting two variables, and 2/73 (2.7%) exhibiting three variables. No correlation was found between the number of donor variables and a poor postoperative result. No infectious complications occurred in 17 patients receiving hearts from potentially infected donors. Hospital mortality rates (30 day) for recipients of high-risk donor versus non-high-risk donor hearts were 8.2% and 6.9%, respectively (not significant). The 1-, 6-, and 12-month actuarial survival rates were 91.7%, 81.2%, and 75.9% for the high-risk donor group and 93.5%, 80.3%, and 77.8% for the non-high-risk donor group (not significant). Among survivors with high-risk donor hearts, mean left ventricular ejection fractions were 0.54 +/- 0.08 at 3 months, 0.55 +/- 0.08 at 1 year, and 0.54 +/- 0.09 at 2 years after transplantation. These results suggest that accepting less than ideal donor hearts can be safe and might be considered when better options are not available.

Adult↗
PubMed1990

Surgical treatment of cardiac tumors: a 25-year experience.

From 1964 to 1989, we performed operations on 133 patients with cardiac tumors. There were 58 male and 75 female patients ranging in age from three days to 81 years; 101 were adults, and 32 were children (less than 12 years of age). Primary tumors (102 benign and 12 malignant) were found in 114 patients and metastatic tumors in 19. Symptoms included congestive heart failure, arrhythmias, emboli, and chest pain. Diagnosis was accomplished through angiography, echocardiography, computed tomography, and magnetic resonance imaging. Operative treatment encompassed techniques ranging from biopsy to complete excision (including hypothermic circulatory arrest and cardiac autotransplantation) depending on the site of disease and the extent of involvement. Overall operative survival was 91%. Twelve patients died early (within 30 days of operation), and follow-up was obtained for 110 (90.9%) of the remaining 121 survivors (total patient-years of follow-up, 572.8; mean follow-up, 5.2 years). Of the 20 patients who died late, 15 had malignant disease. Operative survival for patients with primary cardiac malignancies and for those with metastatic disease was 83% and 68.4%, respectively, with 3 and 5 patients, respectively, still living. We advocate an aggressive surgical approach, especially in patients with benign tumors, who can expect an excellent outcome. For patients with malignant or metastatic disease, palliation and cure are also possible if aggressive surgical actions are taken.

Adenocarcinoma↗
PubMed1990

Use of potentially infected donor hearts for cardiac transplantation.

Despite the nationwide shortage of heart donors, more patients, some of whom are critically ill, are being accepted as candidates for transplantation. Thus, on occasion, we have liberalized our donor criteria to meet the demand. We have recently transplanted 16 potentially infected donor hearts into critically ill recipients. Of these 16 donors, 7 had multiple positive blood cultures as follows: Streptococcus pneumoniae (3), Staphylococcus aureus (2), Klebsiella pneumoniae (1), and Enterobacter sp (1). Seven other donors were accepted despite high fevers (rectal temperature greater than 38.9 degrees C), leukocytosis (greater than 18 x 10(9)/L [greater than 18,000 cells/microL]), and pulmonary infiltrates with positive sputa (Enterobacter [3], Klebsiella pneumoniae [2], and Staphylococcus [2]). Two other donors with hepatitis B surface antigen positivity were deemed at high risk but were used because the recipients were in immediate need. Early mortality (less than or equal to 30 days) among the recipients was 3/16 (18.7%) with 1 patient dying of uncontrolled allograft rejection, 1 of hepatic failure, and 1 of Pseudomonas septicemia. Late mortality (greater than 30 days after operation) occurred in 6 patients: 2 patients died of hepatic failure, 3 died of graft atherosclerosis, and 1 died of iatrogenic hemorrhage after a liver biopsy. Only 1 patient died of infection unrelated to that of the donor, and the other patients had no infectious complications resulting from the organisms identified in their respective donors. Use of potentially infected donor hearts resulted in surprisingly few infectious complications in this group of recipients. This practice can be safe and should be considered when other options are unavailable.

Adult↗
PubMed1989

Effect of prior cardiac surgery on survival after heart transplantation.

We conducted a retrospective analysis of 182 adult orthotopic heart transplant patients who underwent operations at our institution between July 1982 and October 1987 to determine whether prior cardiac operation affects survival. Group I included the 72 patients (39.6%) who had undergone a previous cardiac operation or operations and group II, the 110 (60.4%) who had not. The mean age of the patients in group I was 52.1 +/- 8.1 years and in group II, 46.1 +/- 10.2 years (p less than 0.01). The incidence of ischemic heart disease was 86.1% in group I and 29.1% in group II (p less than 0.01). All patients received cyclosporine-based immunosuppression. More patients in group I than in group II required reoperation for bleeding after transplantation: 18 (25.0%) versus 9 (8.2%) (p less than 0.01). The actuarial 1-year and 3-year survival rates were 77.6% and 66.5%, respectively, for group I and 77.1% and 66.3%, respectively, for group II. Because both groups had similar survival rates, we believe that prior cardiac operation in heart transplant recipients does not compromise long-term survival.

Adult↗
PubMed1989

Improved cardiac function with glucose-insulin-potassium after aortocoronary bypass grafting.

To assess the effectiveness of metabolic support for the heart in patients with refractory heart failure after hypothermic ischemic arrest for aortocoronary bypass grafting we assigned 22 patients to receive either intravenous glucose (50%), insulin (80 IU/L), and potassium (100 mEq/L) at a rate of 1 mL/kg/h for up to 48 hours (GIK) or glucose (5%) and NaCl (0.225%) at the same rate (control). All patients started out with a mean cardiac index of less than 3.0 L/min/m2, were on intraaortic balloon pump assistance, and required inotropic drugs. At 12 and 24 hours cardiac index had increased significantly in the GIK group when compared with the control group (3.6 and 3.4 versus 2.5 and 2.7 L/min/m2, respectively). Time on the intraaortic balloon pump (39 versus 61 hours) and requirements for inotropic drug support were significantly less in GIK group than in the control group. All 11 GIK patients could be weaned from intraaortic balloon pump assistance. At 30 days after operation survival was 10/11 in the GIK group, compared with 7/11 in the control group. We conclude that GIK is both safe and effective in the treatment of refractory left ventricular failure after aortocoronary bypass grafting. The exact mechanism for the beneficial effect of GIK on myocardial contractility remains to be elucidated.

Aged↗
PubMed1989

Bioprosthetic versus mechanical valve replacement in patients with infective endocarditis.

During the 5-year period, 1979-1984, at the Texas Heart Institute, 4,598 patients underwent cardiac valve replacement procedures of which 185 were for acute infective endocarditis. Staphylococcus and streptococcus accounted for 80% of the cases and congestive heart failure was a leading indication in 63%. The purpose of this article is to evaluate the recurrence of endocarditis dependent upon whether the patient had an Ionescu-Shiley bioprosthetic pericardial valve or a mechanical valve (St. Jude Medical). Actuarial freedom from both early and late reoperation was higher for prosthetic valves than bioprosthetic valve patients. We conclude that mechanical valves are the valves of choice in acute infective endocarditis which apparently is the results of less biologic tissue available for exposure to infection by the offending organisms.

Actuarial Analysis↗