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Louis Samuels

Publications and source records attributed to Louis Samuels.

8 recordsLinked to original sources
PubMed2004

Initial experience with the AbioCor implantable replacement heart system.

OBJECTIVE: We sought to evaluate the safety and efficacy of the first available totally implantable replacement heart (AbioCor Implantable Replacement Heart System) in the treatment of severe, irreversible biventricular heart failure in human patients. METHODS: Seven male adult patients with severe, irreversible biventricular failure (>70% thirty-day predicted mortality) who were not candidates for transplantation met all institutional review board study criteria and had placement of the AbioCor Implantable Replacement Heart. All were in cardiogenic shock despite maximal medical therapy, including inotropes and intra-aortic balloon pumps. Mean age was 66.7 +/- 10.4 years (range, 51-79 years). Four of 7 patients had prior operations. Six had ischemic and one had idiopathic cardiomyopathy. All had 3-dimensional computer-simulated implantation of the thoracic unit that predicted adequate fit. At the time of the operation, the internal transcutaneous energy transfer coil, battery, and controller were placed. Biventriculectomy was then performed, and the thoracic unit was placed in an orthotopic position and attached to the atrial cuffs and outflow conduits with quick-connects. The flow was adjusted to 4 to 8 L/min. Central venous and left atrial pressures were maintained at 5 to 15 mm Hg. The device is powered through transcutaneous energy transfer. An atrial flow-balancing chamber is used to adjust left/right balance. The balance chamber and transcutaneous energy transfer eliminate the need for percutaneous lines. RESULTS: There was one intraoperative death caused by coagulopathic bleeding and one early death caused by an aprotinin reaction. There have been multiple morbidities primarily related to preexisting illness severity: 5 patients had prolonged intubation, 2 had hepatic failure (resolved in 1), 4 had renal failure (resolved in 3), and 1 each had recurrent gastrointestinal bleeding, acute cholecystitis requiring laparotomy, respiratory failure that resolved after 3 days of extracorporeal membrane oxygenation, and malignant hyperthermia (resolved). There were 3 late deaths: one caused by multiple systems organ failure (postoperative day 56), one caused by a cerebrovascular accident (postoperative day 142), and one caused by retroperitoneal bleeding and resultant multiple systems organ failure (postoperative day 151). This latter patient was not able to tolerate anticoagulation (no anticoagulation or antiplatelet therapy alone for 80% of the first 60 days) and had a transient ischemic attack on postoperative day 61 and a cerebrovascular accident on postoperative day 130. At autopsy, blood pumps were clean. The 2 patients who had large cerebrovascular accidents had thrombus on the atrial cage struts. These struts have been removed for future implants. There has been no significant hemolysis or device-related infections. The balance chamber has allowed for left/right balance in all patients (left atrial pressure within 5 mm Hg of right atrial pressure). Three patients have taken multiple (>50) trips out of the hospital, and 2 have been discharged from the hospital. Total days on support with the AbioCor are 759. CONCLUSION: The initial clinical experience suggests that the AbioCor might be effective therapy in patients with advanced biventricular failure. There have been no significant device malfunctions. Two of these patients have been discharged from the hospital.

Aged↗
PubMed2004

Biventricular mechanical replacement.

The role of biventricular mechanical support (assist or replacement) is important for the management of severe biventricular cardiac failure. One only has to look at the role of cardiac transplantation to realize the benefit of a natural therapy to end-stage heart disease. Although the technology today is not that different from the technology that existed a decade ago (ie, BioMedicus, BVS 5000, Thoratec, CardioWest), the application of it and the experience gained by it have allowed surgeons to improve the chances of a positive outcome. In terms of new technologies for biventricular mechanical support, the totally implantable versions of a VAD (eg, Thoratec IVAD) or the totally implantable TAH (eg, AbioCor) are promising technologies that add to the spectrum of devices as destination therapy or alternatives to transplantation. And lastly, the role of the Berlin Heart as a tool for the management of biventricular failure in pediatric patients may be realized in the United States in the near future. In conclusion, the treatment of biventricular failure (acute or chronic) with assist or replacement technologies has gained widespread acceptance in the medical and surgical communities. It is now time to use these technologies wisely in an effort to treat the worldwide epidemic of congestive heart failure.

Acute Disease↗
PubMed2004

Transmyocardial laser therapy: a strategic approach.

BACKGROUND: Coronary artery bypass and percutaneous intervention have become the established methods of coronary revascularization in treating angina pectoris. Subsets of angina patients, however, are not amenable to either of these procedures. Transmyocardial laser revascularization (TMR) has been developed as a potential treatment to address such patients, and clinical research to date illustrates the success of TMR for this patient group. STRATEGIC PLAN SUMMARY: Although the symptoms of ischemic heart disease manifest themselves in a variety of ways, the best results with TMR are seen in patients with severe angina rather than in patients with silent ischemia or congestive heart failure. Potential TMR patients receive diagnostic tests to determine if and where the therapy should be applied. A recent cardiac catheterization is required to document the status of and the coronary-system suitability for the planned intervention. It is not appropriate to assume that a patient with nonbypassable, noninterventional coronary artery disease has to be relegated to medical therapy only. Additionally, echocardiography demonstrates the status of cardiac valves and segmental wall motion activity. This knowledge allows the surgeon to determine the sequence of surgery and if abnormalities are present. Once the decision to use TMR use has been made, there are 2 approaches--sole therapy or adjunctive therapy. TMR is not to be substituted for a feasible bypass graft, but the best time to make this decision may well be during the surgery itself, because grafts that appear surgically feasible on an angiogram may be less feasible after the chest has been opened. The decision to perform sole-therapy TMR in the absence of bypassable vessels clearly must be made before opening the chest. Whether to use cardiopulmonary bypass (CPB) and the sequence in which to perform TMR and bypass grafts are based on surgeon preference. The advantage of performing TMR on CPB is that channels can quickly be lased without pause. A potential advantage of performing TMR before bypass grafts is that "channel leak" (bleeding) can be minimized by the conclusion of the surgery. Complete revascularization has become technically more difficult because of the increasing use of percutaneous approaches and because patients are being referred for coronary artery bypass grafting much later in the course of their coronary disease progression than before. TMR may well be a viable alternative to bypassing a heavily diseased, previously intervened, small-diameter coronary artery. Thus, a model in which myocardial perfusion is considered within the context of the natural circulation can be conceived as an alternative to a model in which circulation is altered by interventional, surgical, and/or transmyocardial methods. TMR has been shown to be effective in accomplishing a complete revascularization when the restoration of circulation to ischemic territories with interventional therapy, bypass surgery, or a combination of both has been ineffective. We recommend that interested users follow this "complete revascularization strategy" algorithm for all ischemic vessels being considered for interventional or surgical treatment. Running each diseased vessel through this thought process will ensure that available treatment options are considered in the optimization of a patient's outcome. CONCLUSION: The use of TMR for angina relief has evolved into a clinically proven technology that has enabled physicians to address difficult revascularization cases with a therapy that is safe and effective.

Angina Pectoris↗
PubMed2003

The AbioCor implantable replacement heart.

The AbioCor implantable replacement heart (IRH) is the first available totally implantable artificial heart. We recently initiated a multicenter trial of this device in patients with severe, irreversible biventricular failure. Patients who were not candidates for other therapies, including transplantation, were evaluated. All candidates were adults with inotrope-dependent biventricular failure, whose 30-day predicted mortality was higher than 70%. A three-dimensional computerized fit study predicted fit of the AbioCor thoracic unit in all recipients. At operation, the internal battery controller and transcutaneous energy transfer unit were placed. The AbioCor thoracic unit was placed in an orthotopic position after incision of the ventricals. There were 2 intraoperative deaths (due to intraoperative bleeding or aprotinin reaction). Four late deaths were recorded, 1 from multisystem organ failure and 3 cerebrovascular accidents. Autopsy revealed thrombus on the atrial struts of the 3 patients with cerebrovascular accident. Blood pumps and valves were clean on all patients. Significant morbidity was observed, primarily related to preexisting severity of illness. However, 3 patients recovered to the point of being able to take multiple trips outside of the hospital. Two patients were discharged from the hospital, with 1 patient being discharged home for more than 7 months. No significant device malfunctions or multi-system organ failure device-related infections were noted. The AbioCor IRH may be effective therapy for patients with end-stage heart failure. Many milestones have been achieved in the initial trial in humans, including the successful discharge of a patient to home and no significant device malfunctions. The occurrence of stroke is likely related to the presence of thrombus on the atrial struts and may be decreased as these atrial struts have been removed for future clinical implants.

Aged↗
PubMed2003

The AbioCor totally implantable replacement heart.

The AbioCor artificial heart (Abiomed, Inc., Danvers, MA) represents the latest technologic advancement in the quest for a total heart replacement system. The AbioCor is an electric heart with fully implantable components. The Food and Drug Administration approved a clinical trial in January 2001. The clinical trial was designed as an initial feasibility study to determine the safety and efficacy of this first generation system. The study criteria include end-stage adult heart failure patients who are not transplant candidates. These patients have biventricular failure with a predicted 30-day life expectancy of less than 30%. On July 2, 2001 the first AbioCor device was implanted. Six other patients have undergone implantation to date. Four of the seven have been successful as defined by the study parameters of 60-day survival with improved quality of life. Two patients were discharged from the hospital. Outpatient activities were possible in four patients. There have been no device malfunctions and no device-related infections. The trial is active and enrollment is ongoing.

Aged↗
PubMedDate not supplied

Clinical use of the abiomed BVS 5000 as a pulsatile extracorporeal membrane oxygenation unit.

The traditional extracorporeal membrane oxygenation circuit uses a centrifugal pump. These pumps require close monitoring and are subject to complications. In addition, they do not take advantage of the potential benefits of pulsatile flow. These extracorporeal membrane oxygenation circuits use a single pump with an inline oxygenator. If cardiac failure persists after respiratory recovery has occurred, removal of the oxygenator requires an additional procedure to convert the patient to biventricular support. This report describes a circuit in which an oxygenator is connected to a pulsatile ventricular assist device. Single and dual circuit configurations are illustrated. Recommendations for pulmonary care during support are also described.

Angioplasty↗
PubMedDate not supplied

Incorporation of an in-line filter for ultrafiltration or hemodialysis to the Abiomed BVS5000 ventricular assist device.

Multiple organ system dysfunction is an associated finding in patients requiring acute ventricular assist device (VAD) support. In the setting of acute renal failure, percutaneous catheters are placed for hemodialysis and/or ultrafiltration. Incorporation of an ultrafiltration or hemodialysis system in the Abiomed BVS5000 VAD circuit is a simple maneuver that eliminates the need for an additional catheter, thereby reducing the vascular and infectious complications associated with these catheters. We recommend splicing connectors into the outflow tubing of the right VAD circuit for attachment to an ultrafiltration or hemodialysis unit. This technique is a safe, simple, and reliable method by which to perform intermittent or continuous ultrafiltration or hemodialysis.

Acute Kidney Injury↗