CORRESPONDENCE
Ann Thorac Surg 1992;541018-24
5. 6.
7.
8. 9.
platelet function, fibrinolysis, complement and renal function after cardiopulmonary bypass. J Thorac Cardiovasc Surg 1991; 101:958-67. Royston D. The serine antiprotease aprotinin (Trasylol). A novel approach to reduce postoperative bleeding. Blood Coag Fibrinol 1990;1:55-69. Have1 M, Teufelsbauer H, Knob1 P, et al. Effect of intraoperative aprotinin administration on postoperative bleeding in patients undergoing cardiopulmonary bypass operation. J Thorac Cardiovasc Surg 1991;101:968-72. Edmunds LH, Niewiarowski S, Colman RW. Aprotinin [Letter]. J Thorac Cardiovasc Surg 1991;101:1103-4. Quinn JP, Counts GW, Meyers JD. Intracardiac infections due to coagulase negative Staphylococcus associated with Hickman catheters. Cancer 1986;571079-82. Liepman MK, Jones PG, Kauffman CA. Endocarditis as a complication of indwelling right atrial catheters in leukemic patients. Cancer 1984;54:804-7.
Thermo Cardiosystems Left Ventricular Assist Device To the Editor: As one of the principal investigators of the HeartMate left ventricular assist device, I would like to comment on the article by Phillips and colleagues [l]that appeared in a recent issue of The Annals of Thoracic Surgery. Their report and the following commentary by Hill focus on surgical complications in 3 patients who underwent bridge-to-transplant procedures with the HeartMate. It is important to stress that the complications were related primarily to the operation and, thus, are not a reflection on the suitability and efficacy of the device. Research on the HeartMate has been ongoing for more than a decade, and our current clinical experience supports its usefulness in providing long-term support for the failing left ventricle [2]. The HeartMate is particularly suitable for patients with chronic congestive heart failure that is characterized primarily by left ventricular failure, a condition in which a heart transplant may also be considered appropriate treatment. The ultimate use of the HeartMate is not as a bridge to transplantation. The device was originally conceived as a longterm left ventricular assist system, at a time when heart transplantation was not a very successful option. Today, heart transplantation is a successful alternative for patients with end-stage heart failure; unfortunately, many more patients are awaiting a heart transplant than there are available donors. According to the United Network for Organ Sharing [3], an average of fewer than 6 donor hearts are available each day in the United States for more than 2,300 patients who are on the waiting list. The HeartMate was intended to fill the void left by the shortage of donor hearts and to give patients who are not appropriate candidates for heart transplantation a chance for survival. An intraabdominal device is the only suitable choice for these patients. Our experience has shown that the HeartMate can allow patients to return to active class I cardiac status with minimal limitations, particularly when the newer, electrically powered model is used. Attributing surgical problems to the device is inappropriate. Intraabdominal or extraperitoneal placement of the HeartMate is a relatively straightforward surgical procedure. Patients appear to tolerate intraabdominal placement well, and in our series there has been only 1 case of intestinal obstruction related to intraabdominal placement. If the goal were simply to provide a bridge to transplantation, an extracorporeal mechanical circulatory assist device could be used and is certainly more convenient for the surgeon to insert and to remove. We must work toward developing a permanent device, however, as this is one way to treat more patients with terminal heart
1019
failure than are currently being treated by heart transplantation. The number of patients awaiting transplants exceeds, by far, the number of potential donors. An extracorporeal device cannot solve the problem caused by too few donors, nor can it be used to provide practical, permanent, implantable cardiac support, which is the only way a patient could live normally with one of these devices. Although an extracorporeal device is simple to implant for the surgeon, this is certainly no justification for its use at a time of critical donor shortage, when a donor heart could just as easily be allocated to a patient waiting for a transplant without a bridging device. Thus, the real goal of bridge-to-transplant procedures must be research that will lead to a clinically practical, permanently implantable device that will allow us to treat a greater number of patients with end-stage heart failure.
0. H . Frazier, M D Cullen Cardiovascular Research Laboratories Transplant Service Texas Heart Institute POBox20345 Houston, TX 77225-0345
References 1. Phillips WS, Burton NA, Macmanus Q, Lefrak EA. Surgical complications in bridging to transplantation: the Thermo Cardiosystems LVAD. Ann Thorac Surg 1992;53:482-6. 2. Frazier OH, Rose E, Macmanus Q, et al. Multicenter clinical evaluation of the HeartMate 1000 IP left ventricular assist device. Ann Thorac Surg 1992;53:1080-90. 3. The National Organ Procurement and Transplantation Network. UNOS Annual Report for January 1,1990-June 30,1991. Richmond, VA: UNOS, 1991.
Reply
To the Editor:
We appreciate and concur with the comments of Dr Frazier in response to both our article and the invited comments of Dr Hill. The most important point to emphasize is that in spite of complications, the HeartMate left ventricular assist device provided excellent support in a variety of physiologic conditions without malfunction. Even in the setting of mediastinitis and peritonitis, the device continued to function superbly, and we were able to completely clear the infection while awaiting cardiac transplantation. We have now used the HeartMate to successfully bridge 8 patients to cardiac transplantation. One patient is currently awaiting transplantation on the device. We agree with Dr Frazier that this device is uniquely adapted for long-term use and will ultimately serve as a substitute for, rather than a bridge to, cardiac transplantation. As Dr Frazier correctly notes, the only mechanical device that will ever alleviate the growing shortage of donor hearts is a device that can be permanently implanted to support a failing left ventricle. Clearly, the first-generation extracorporeal left ventricular assist devices will never allow for such support. By contrast, the intraabdominally placed HeartMate left ventricular assist device has demonstrated to us a remarkable record of dependability and relative freedom from complications. In more than 600 patient-days in our 9 patients, there has never been a single thromboembolic event on a regimen consisting of only 80 mg of aspirin daily. There have been no system failures. All patients have been fully ambulatory and returned to functional class I status. Although there are potential complications associated with the use of any mechanical device, the HeartMate left ventricular
Ann Thorac Surg 1992;541018-24
5. 6.
7.
8. 9.
platelet function, fibrinolysis, complement and renal function after cardiopulmonary bypass. J Thorac Cardiovasc Surg 1991; 101:958-67. Royston D. The serine antiprotease aprotinin (Trasylol). A novel approach to reduce postoperative bleeding. Blood Coag Fibrinol 1990;1:55-69. Have1 M, Teufelsbauer H, Knob1 P, et al. Effect of intraoperative aprotinin administration on postoperative bleeding in patients undergoing cardiopulmonary bypass operation. J Thorac Cardiovasc Surg 1991;101:968-72. Edmunds LH, Niewiarowski S, Colman RW. Aprotinin [Letter]. J Thorac Cardiovasc Surg 1991;101:1103-4. Quinn JP, Counts GW, Meyers JD. Intracardiac infections due to coagulase negative Staphylococcus associated with Hickman catheters. Cancer 1986;571079-82. Liepman MK, Jones PG, Kauffman CA. Endocarditis as a complication of indwelling right atrial catheters in leukemic patients. Cancer 1984;54:804-7.
Thermo Cardiosystems Left Ventricular Assist Device To the Editor: As one of the principal investigators of the HeartMate left ventricular assist device, I would like to comment on the article by Phillips and colleagues [l]that appeared in a recent issue of The Annals of Thoracic Surgery. Their report and the following commentary by Hill focus on surgical complications in 3 patients who underwent bridge-to-transplant procedures with the HeartMate. It is important to stress that the complications were related primarily to the operation and, thus, are not a reflection on the suitability and efficacy of the device. Research on the HeartMate has been ongoing for more than a decade, and our current clinical experience supports its usefulness in providing long-term support for the failing left ventricle [2]. The HeartMate is particularly suitable for patients with chronic congestive heart failure that is characterized primarily by left ventricular failure, a condition in which a heart transplant may also be considered appropriate treatment. The ultimate use of the HeartMate is not as a bridge to transplantation. The device was originally conceived as a longterm left ventricular assist system, at a time when heart transplantation was not a very successful option. Today, heart transplantation is a successful alternative for patients with end-stage heart failure; unfortunately, many more patients are awaiting a heart transplant than there are available donors. According to the United Network for Organ Sharing [3], an average of fewer than 6 donor hearts are available each day in the United States for more than 2,300 patients who are on the waiting list. The HeartMate was intended to fill the void left by the shortage of donor hearts and to give patients who are not appropriate candidates for heart transplantation a chance for survival. An intraabdominal device is the only suitable choice for these patients. Our experience has shown that the HeartMate can allow patients to return to active class I cardiac status with minimal limitations, particularly when the newer, electrically powered model is used. Attributing surgical problems to the device is inappropriate. Intraabdominal or extraperitoneal placement of the HeartMate is a relatively straightforward surgical procedure. Patients appear to tolerate intraabdominal placement well, and in our series there has been only 1 case of intestinal obstruction related to intraabdominal placement. If the goal were simply to provide a bridge to transplantation, an extracorporeal mechanical circulatory assist device could be used and is certainly more convenient for the surgeon to insert and to remove. We must work toward developing a permanent device, however, as this is one way to treat more patients with terminal heart
1019
failure than are currently being treated by heart transplantation. The number of patients awaiting transplants exceeds, by far, the number of potential donors. An extracorporeal device cannot solve the problem caused by too few donors, nor can it be used to provide practical, permanent, implantable cardiac support, which is the only way a patient could live normally with one of these devices. Although an extracorporeal device is simple to implant for the surgeon, this is certainly no justification for its use at a time of critical donor shortage, when a donor heart could just as easily be allocated to a patient waiting for a transplant without a bridging device. Thus, the real goal of bridge-to-transplant procedures must be research that will lead to a clinically practical, permanently implantable device that will allow us to treat a greater number of patients with end-stage heart failure.
0. H . Frazier, M D Cullen Cardiovascular Research Laboratories Transplant Service Texas Heart Institute POBox20345 Houston, TX 77225-0345
References 1. Phillips WS, Burton NA, Macmanus Q, Lefrak EA. Surgical complications in bridging to transplantation: the Thermo Cardiosystems LVAD. Ann Thorac Surg 1992;53:482-6. 2. Frazier OH, Rose E, Macmanus Q, et al. Multicenter clinical evaluation of the HeartMate 1000 IP left ventricular assist device. Ann Thorac Surg 1992;53:1080-90. 3. The National Organ Procurement and Transplantation Network. UNOS Annual Report for January 1,1990-June 30,1991. Richmond, VA: UNOS, 1991.
Reply
To the Editor:
We appreciate and concur with the comments of Dr Frazier in response to both our article and the invited comments of Dr Hill. The most important point to emphasize is that in spite of complications, the HeartMate left ventricular assist device provided excellent support in a variety of physiologic conditions without malfunction. Even in the setting of mediastinitis and peritonitis, the device continued to function superbly, and we were able to completely clear the infection while awaiting cardiac transplantation. We have now used the HeartMate to successfully bridge 8 patients to cardiac transplantation. One patient is currently awaiting transplantation on the device. We agree with Dr Frazier that this device is uniquely adapted for long-term use and will ultimately serve as a substitute for, rather than a bridge to, cardiac transplantation. As Dr Frazier correctly notes, the only mechanical device that will ever alleviate the growing shortage of donor hearts is a device that can be permanently implanted to support a failing left ventricle. Clearly, the first-generation extracorporeal left ventricular assist devices will never allow for such support. By contrast, the intraabdominally placed HeartMate left ventricular assist device has demonstrated to us a remarkable record of dependability and relative freedom from complications. In more than 600 patient-days in our 9 patients, there has never been a single thromboembolic event on a regimen consisting of only 80 mg of aspirin daily. There have been no system failures. All patients have been fully ambulatory and returned to functional class I status. Although there are potential complications associated with the use of any mechanical device, the HeartMate left ventricular
