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.

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.

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.

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.

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)

Bacterial mediastinitis after heart transplantation.

Bacterial mediastinal abscess or mediastinitis developed in nine (2.5%) of 361 consecutive patients who underwent isolated heart transplantation at the Texas Heart Institute. All nine patients had at least one predisposing factor that may have contributed to the development of mediastinitis. These included insulin-dependent diabetes mellitus, repeat operation for postoperative mediastinal hemorrhage, Staphylococcus aureus pneumonitis, and cardiac allograft rejection in the early postoperative period (less than 30 days), necessitating steroid pulse therapy alone or in combination with murine-derived monoclonal antibody (OKT3). In six of the nine patients, the diagnosis of mediastinitis was made on the basis of clinical findings (unstable sternum and incisional erythema, with or without gross purulence), and in the other three patients, diagnosis was confirmed by computed tomography of the chest. Culture data were unequivocal in all patients; S. aureus was the most frequent (five patients), followed by S. epidermidis (two patients), and Enterobacter cloacae (two patients). Computed tomography-directed percutaneous drainage and systemic antibiotics were successful in treating two of three patients who had stable sternums with mediastinal abscess. In the remaining seven patients, sternal and mediastinal debridement with rewiring of the sternum was successfully applied. No patient required muscle or omental flap coverage, and no patient experienced a recurrence of mediastinitis during an average follow-up period of 35 months (range, 12 to 46 months).

Adjuvant native heart surgery during heterotopic heart transplantation: two case reports.

The results of heterotopic heart transplantation may be further improved if repairs on native heart abnormalities are performed just before implantation of the allograft. Such procedures increase the potential for the recipient's own heart to recover function and, thus, to maintain circulation if the heterotopic heart malfunctions or fails. The native hearts of two of our patients, both women, showed signs of greater contractility and ejection after repair and were able to provide adequate circulatory support during periods of donor heart failure. The first patient required ventricular aneurysmectomy and coronary artery bypass grafting, and the second, native mitral valve repair. Moreover, when persistent ventricular fibrillation occurred in the donor heart of the first patient, a donor cardiectomy was performed, and the recipient heart functioned well thereafter. As more adjuvant operations are performed and the results evaluated, we may find that heterotopic operations would be suitable in a greater variety of heart transplant candidates.

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.

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.

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.

Blunt trauma to the heart: the pathophysiology of injury.

Blunt injuries to the heart are common and potentially lethal. These injuries often go undetected while more obvious problems are treated. A cardiac injury should be suspected in any patient who sustains severe chest trauma. The spectrum of cardiac trauma ranges from injuries with no actual cellular damage (myocardial concussion) to cardiac chamber rupture. The pathophysiology, diagnosis, and treatment of these injuries are discussed.

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.

Improved survival after Hemopump insertion in patients experiencing postcardiotomy cardiogenic shock during cardiopulmonary bypass.

Immediate placement of a Hemopump (HP) ventricular assist device was undertaken in nine patients (seven men, two women) after other attempts at weaning from cardiopulmonary bypass (CPB) after coronary bypass surgery had failed. All nine patients (100%) were successfully weaned from CPB, and six (63.3%) gradually improved enough to permit removal of HP support. Five (83.3%) of the six who were weaned from CPB survived beyond hospital discharge. HP support was evaluated in terms of vital organ function, incidence of complications, and clinical outcome. In both survivors (S) and nonsurvivors (NS), serial hemodynamic measurements were taken. Although there were few differences in hemodynamic parameters between groups at 4 hr, by 24 hr the S group had markedly improved cardiac index, Glasgow Coma Scale, urinary output, and pulse pressure and required far less inotropic support than did the NS group. All four patients who required high dose inotropic agents to maintain acceptable end-organ perfusion on HP support died; three were unable to tolerate weaning from the HP, and all died within 72 hr of surgery because of ineffective myocardial recovery. None of the survivors required additional early inotropic augmentation. Renal perfusion appeared to be well maintained, even with mean arterial pressures below 60 mmHg during HP support. There were no episodes of hemolysis, infection, or limb ischemia in either group. Thus, the Hemopump provided excellent circulatory support for those patients who could not be weaned from CPB by traditional methods.

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.

Treatment of cardiac allograft failure by use of an intraaortic axial flow pump.

Since April 1988 we have used the Hemopump device, a new means of circulatory support, to successfully treat three orthotopic heart transplant recipients with biventricular failure refractory to conventional therapy. The Hemopump device is a 21F catheter-mounted, transvalvular, intraaortic axial flow pump. Power to the pump is percutaneously transmitted from an external electromechanical drive console by a flexible drive cable. We first used the pump in a 61-year-old man in whom severe steroid-resistant rejection developed 28 days after heart transplant, resulting in cardiogenic shock (cardiac index less than 2.0 L/min/m2) despite maximal inotropic support. In the second case a 49-year-old man with no evidence of pulmonary hypertension sustained cardiac arrest 2 hours after heart transplant, necessitating open chest massage and emergency cardiopulmonary bypass. The third patient was a 9-year-old boy in whom rejection developed 5 months after heart transplant, resulting in congestive heart failure that was unresponsive to maximal medical therapy. The device was implanted by way of the femoral artery approach in the first case, the ascending aorta in the second, and the distal abdominal aorta in the third. Duration of support was 46 hours, 65 hours, and 6 days, respectively. Increased blood flow provided by the pump ranged from 2 to 4 L/min. No device-related complications, such as hemolysis, infection, or thromboembolic events, occurred. All patients recovered normal heart function and were weaned from the device. The first patient is well after 12 months. The second patient died of metastatic lymphoma at 2 months, and the third died of Pseudomonas pneumonia after 2 weeks.(ABSTRACT TRUNCATED AT 250 WORDS)

Use of a new device in cannulation of the great vessels: cannula introducer.

To improve the existing complications of the arterial cannulation technique, an introducer was developed that could minimize the trauma to the vessel wall and intima, simplify the operation and avoid the usual complications such as air or emboli strokes, misdirection and malrotation of the cannula tip within the artery. The Introducer consists of an extendable blade proportionate to the size of the cannula to be inserted. The movement of the blade is accomplished by a trigger in the handle of the device. The cannula is also released by another trigger in the handle. Ninety heart patients in whom this device was used underwent open heart surgery, and there were no single case of a major stroke, air or thrombo-embolism, or undue blood loss. One patient developed a transient right hand paresis that subsided after removal of the arterial line. The results were compared to 65 patients with the current method of cannulation and in whom this device was not used. In this latter group there were five cases of major neurological deficits, one aortic dissection, one case of embolism to the leg and four cases of abnormal bleeding which necessitated takebacks in the first 24 hours of post-operative period.