| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Ann Thorac Surg 2004;77:133-142
© 2004 The Society of Thoracic Surgeons
a Texas Heart Institute at St. Luke's Episcopal Hospital, Houston, Texas, USA
b Oxford Heart Centre, Oxford, United Kingdom
* Address reprint requests to Dr Frazier, Texas Heart Institute, PO Box 20345, Houston, TX 77225-0345, USA
e-mail: mmallia{at}heart.thi.tmc.edu
Presented at the Thirty-ninth Annual Meeting of The Society of Thoracic Surgeons, San Diego, CA, Jan 31–Feb 2, 2003.
 |
Abstract |
|---|
 Top Abstract IntroductionPatients and methodsResultsCommentConclusionAcknowledgmentsDiscussionReferences |
|---|
METHODS: We analyzed the physiologic and anatomic effect of using the Jarvik 2000 pump for cardiac support in 23 patients in whom the device was applied as a bridge to transplant under the protocol approved by the Food and Drug Administration Investigational Device Exemption. The device was used as a bridge to transplantation in 20 patients and as destination therapy in 3 patients.
RESULTS: In the bridge-to-transplant group, 14 patients underwent transplantation, 5 died during the circulatory support period and 1 is in an ongoing study. The support period lasted an average of 90 days. For the survivors, the follow-up period has averaged 16 months. Within the first 48 postoperative hours, the average cardiac index increased by 65% (from 1.77 ± 0.24 to 2.92 ± 0.60 L · min-1 · m-2, p = 0.00000002), the systemic vascular resistance decreased by 42% (from 1604 ± 427 to 930 ± 330 dynes/sec per cm2, p = 0.00001), and the pulmonary capillary wedge pressure (PCWP) decreased by 41.8% (from 23 ± 5.1 to 13.4 ± 6.6 mm Hg, p = 0.00009). Similar results were seen for the patients undergoing destination therapy. Cardiac index increased 89.5% (from 1.9 ± 0.1 to 3.6 ± 0.6, p = 0.046) and PCWP decreased by 52.2% (from 23 ± 10 to 11 ± 2, p = 0.22). In that group, 1 patient died unexpectedly from an accident 382 days after device implantation. The 2 survivors remain in New York Heart Association (NYHA) functional class I at 700 to 952 days after implantation.
CONCLUSIONS: The Jarvik 2000 can offer effective long-term support for patients with chronic heart failure and NYHA class IV status. However, the new physiology produced by continuous offloading of the heart throughout the cardiac cycle has introduced unique clinical problems. The understanding of the problems generated by this biotechnological interface is essential for obtaining optimal clinical outcomes.
|
Introduction |
|---|
|
TopAbstractIntroductionPatients and methodsResultsCommentConclusionAcknowledgmentsDiscussionReferences |
|---|
Continuous-flow pumps were first investigated as a means of minimizing VAD size and eliminating the need for external venting required for long-term, pulsatile pumps [5, 6]. Continuous-flow pumps minimize pulsatility-related trauma, which has long been known to increase the risk of infection [5, 6]. Also, because these pumps are small and, in the case of the Jarvik 2000 pump (Jarvik Heart Inc, New York, NY), positioned intraventricularly the potentially serious complication of pump-pocket infection is eliminated. Under normal operating conditions, continuous-flow pumps offload the failed left ventricle throughout the cardiac cycle. Their ability to immediately offload the failing heart should ideally result in improvement of native ventricular function.
Preliminary clinical studies have reported that continuous-flow pumps can provide adequate circulatory support for periods ranging from months to years [7–9]. Although these devices may offer certain advantages in selected patients, new problems have been encountered in the clinical management of patients who receive the device. The entropy created in the circulatory system by the pulsatile and nonpulsatile pump interface results in a new physiology that may affect patient selection and management.
We have been testing one such pump, the Jarvik 2000 VAD, through in vitro, in vivo, and clinical studies for more than a decade. This pump is currently undergoing clinical testing in the United States as a bridge to transplantation, and in Europe as both a bridge to transplantation and as destination therapy. This report analyzes our experience with this new technology. We review some of the problems that we have encountered in its use and discuss the impact of the resulting unique physiology on evolving patient selection.
|
Patients and methods |
|---|
|
TopAbstractIntroductionPatients and methodsResultsCommentConclusionAcknowledgmentsDiscussionReferences |
|---|
|
|
Implant operation
The pump may be implanted through either a left thoracotomy incision or a conventional median sternotomy. The implant operation has been described in detail elsewhere [8, 9, 11]. Briefly, the device may be implanted with or without the aid of partial cardiopulmonary bypass [11, 12]. Anastomosis of the outflow graft to the aorta is performed with a partial occlusion clamp (late in our series, 3 patients had the outflow graft anastomosed to the ascending aorta; in all the other cases, the outflow graft was sewn to the descending aorta). Pledgeted sutures are used to position a silicone/polyester sewing cuff near the apex of the heart. The power cable is then tunneled through the abdominal wall to an exit site in the right upper quadrant or is tunneled through the left side of the chest and neck for attachment of the posterior auricular pedestal. Either the heart is slowed with esmolol or adenosine, or ventricular fibrillation is induced for coring an opening through the sewing cuff. The pump is then inserted and secured. As the pumping action begins, air is removed from the graft, and the patient is slowly weaned from cardiopulmonary bypass if it has been used.
Hemodynamic assessment
Intraoperative hemodynamic assessment is performed with transesophageal echocardiography, a pulmonary artery catheter, an arterial pressure line, and an ultrasonic flow probe placed temporarily on the pump's outflow graft. Hemodynamic values are recorded at each pump speed. Pressure-volume loops were calculated in 2 patients at time of implant and explant by means of direct intraventricular pressure monitoring. The optimal pump speed setting (generally 9000 to 10,000 rpm) is determined by adjusting the speed over the entire range of settings (8000 to 12,000 rpm in 1000-rpm increments) while echocardiographic images are recorded. The optimal speed is that which allows maximal augmentation of cardiac output, particularly when the aortic valve is opening and the native heart is contributing to cardiac output. Before the thoracotomy incision is closed, the ultrasonic flow probe is removed from the outflow graft.
Postoperatively, serial transthoracic echocardiographic studies are performed to further assess hemodynamic function. It was important that cardiac pulsatility and aortic valve opening be achieved as the flow was reduced. This indicated a return to the assisted heart of a normal Frank Starling's mechanism, ie, as the native heart was loaded, it was able to respond with increased contractility. Hemodynamic function is also assessed through values obtained by a pulmonary artery catheter and an arterial pressure line. Once all the monitoring lines have been removed, hemodynamic assessment is achieved by routinely evaluating the patient's vital signs and by performing echocardiographic studies when indicated.
Two methods are available for evaluating the pump's contribution to the total cardiac output. An ultrasonic flow probe may be placed on the outflow graft intraoperatively for direct measurement of blood flow. Alternatively, postoperative echocardiographic studies may be performed to measure the blood flow in the right and left ventricular outflow tracts; the difference between these two values is the pump flow. To assess the contribution of the heart and the pump to total cardiac output in this study, comparison to total cardiac output was made with the ultrasonic flow probe on at different pump speeds to assess the contribution of the heart and the pump to the total cardiac output.
To assess changes in myocardial function during Jarvik 2000 support in 2 patients, we measured the slope (Emax) of the end-systolic pressure-volume relationship, which indicated left ventricular function independent of the preload and afterload, immediately before implantation and explantation of the Jarvik 2000 pump. End systole was determined by closure of the aortic valve on echocardiogram. This lengthy physiologic monitoring must be reserved, however, for clinically stable patients. Also, the logistics of performing this with personnel and equipment limited its application.
Informed consent was obtained from all patients, and the studies were approved by each institution's ethics committee and the appropriate US and UK governmental agencies.
Statistical methods
Statistical differences were determined by using the paired t test. Significance was considered at p less than 0.05. The correlation coefficient (R) was determined with a polynomial inverse first order calculation. Data were analyzed using ANOVA followed by the Bonferroni test for multiple comparisons.
|
Results |
|---|
|
TopAbstractIntroductionPatients and methodsResultsCommentConclusionAcknowledgmentsDiscussionReferences |
|---|
|
All three destination-therapy implants were performed in Great Britain. These patients were critically ill, class IV congestive heart failure patients, but were still able to be home-managed on maximal medical therapy [13]. Immediate postoperative assessment indicated considerable improvement in the patients' clinical status and hemodynamic function. Within the first 24 hours postoperatively, the average CI increased by 89.5% (from 1.9 ± 0.1 to 3.6 ± 0.6 L · min-1 · m-2, p = 0.046), and the PCWP decreased by 52.2% (from 23 ± 10 to 11 ± 2 mm Hg, p = 0.22). The patients were discharged from the hospital 59, 25, and 28 days, respectively, after the implant surgery. As customary in the British system, postoperative follow-up care was relegated to the patients' family physician. Only if problems occurred that could not be satisfactorily managed by the family practitioner was a patient referred to the heart center. After 382 days of support, 1 patient died of a subdural hematoma after an accidental fall at home. It was determined that this incident was not caused by a device malfunction. The remaining 2 patients continue to be supported at 700 days and 952 days (as of January 2003). Both patients are in NYHA class I and are receiving minimal medical therapy (anticoagulation and antihypertensive medications), as needed. Both patients were in NYHA class IV at the time of implant. Their marked physiologic improvement has allowed them to resume normal activities for their ages. One of them has traveled internationally on multiple occasions and has written two books. In both patients technical problems have been minimal.
|
Comment |
|---|
|
TopAbstractIntroductionPatients and methodsResultsCommentConclusionAcknowledgmentsDiscussionReferences |
|---|
Our early experience with the use of the intraaortic balloon pump (IABP) graphically demonstrated the importance of proper device-patient matching. Only 2 of the first 35 patients survived in the first 2 years of IABP use. Such outcomes today would have prohibited FDA approval of this universally accepted, lifesaving technology. With more experience in proper patient selection, the IABP evolved to play an essential role in the treatment of patients with advanced heart failure.
Initial debates surrounding continuous-flow blood pump technology were focused on the physiologic effects of nonpulsatile flow on the circulatory system and end-organ function. As is often the case, the real clinical issues and problems that we encountered with use of the left-sided, continuous-flow pump had little to do with this consideration. Some of our clinical observations to date will be highlighted.
Impact of the continuous-flow pump on starling's law in the failed heart and its importance in patient selection
Our experience has consistently demonstrated the most optimal clinical outcomes in patients in which the Starling response of the native heart is restored (Fig 2).
Before implant all patients were suffering from chronic heart failure, and their clinical status was critical. They were receiving maximal medical therapy, respiratory support, and/or IABP support in the intensive care unit. Therefore, by definition, their chronic, advanced heart failure had progressed to a compromise of the Starling's response.
|
Impact of the Continuous-Flow pump on right ventricular function
All left ventricular pumps introduce an altered physiology. The implantable, pulsatile left VADs (LVADs) lower intraventricular and intraatrial pressure not to normal levels, but to subnormal levels. In the usual (automatic) operating mode of the HeartMate (Thoratec Corporation, Pleasanton, CA) or Novacor (Baxter Health Care Corporation, Deerfield, IL) devices, the native aortic valve does not open, and left atrial and intraventricular pressures are reduced to levels that, in the normal circulatory system, would only occur in hypovolemic shock. On the other hand, right ventricular and right atrial pressures after left ventricular pump implantation are elevated, frequently even higher than their preoperative levels, and are compatible with advanced heart failure [14, 15].
At the atrial level, such pressure differential can cause shunting of unoxygenated blood if a patent foramen ovale is present. This shunting results, physiologically, in an acute elevation of right-sided pressures following successful LVAD implantation. This altered physiology can be even further accentuated with a continuous-flow pump. If cardiac output decreases because of lack of left ventricular filling (due to right ventricular failure, high PVR, or both), it is hazardous to attempt improving the patient's condition by increasing pump speed in the hope of enhancing cardiac output. Without improvement of left ventricular inflow, increasing the rpm will cause further diminution of the left ventricular cavity, worsening the ventricular septal shift (Fig 3). This further impairs right ventricular function, diminishing the already compromised left ventricular inflow. Increasing shear may also result in severe hemolysis. This worsening spiral may require aggressive intervention with a right ventricular support device to avoid a fatal outcome.
|
The potential for myocardial recovery in patients supported by the continuous-flow pump seems enhanced [16, 17]. This may relate to loss of the isovolumetric phase of myocardial contraction by continuous offloading of the heart. This phase of the normal cardiac cycle is a phase of heightened myocardial oxygen demands. The continuous-flow pump, by eliminating isovolumetric contractions, assures resting of the native heart throughout the cardiac cycle. The asynchronous contraction of the native heart and the pulsatile LVAD increases the duration of isovolumetric contractions when the native heart pumps against a closed aortic, mitral, and pump inflow valve. For example, if the native heart and the LVAD are pumping independently at 70 beats/min and both pumps have the same systolic duration (1/3 cardiac cycle), then only 1/9 of the contractions will be synchronous. The other 8/9 will be asynchronous with concomitant lengthening of isovolumetric contraction duration. Our limited studies in patients who have undergone transplant following support with the Jarvik 2000 pump have given us the impression that this technology results in accelerated myocardial recovery compared with patients supported with the conventional, pulsatile LVAD.
Implications of the Continuous-Flow pump on the systemic circulation
The functioning continuous-flow pump augments diastolic pressure and flow and lowers peak systolic pressure. In any circumstance, this results in a dampening of pulsatility and an increase in laminar flow in the periphery of the vessel. In patients with partial atherosclerotic obstructions this can result in stasis distal to the obstruction, which would enhance platelet aggregation and increase the possibility of occlusion of such vessels. We have observed this phenomenon in 2 patients and are concerned that patients with advanced arteriosclerosis may require more attention to aggressive anticoagulation and maintenance of pulsatility.
Another observation that we believe could be related to dampened pulsatility is gastrointestinal bleeding from arteriovenous (AV) malformations. This phenomenon was first described by Heyde in a letter to the New England Journal of Medicine in 1958 [18], and was subsequently reported by other observers [19–22]. Three of our patients developed chronic blood loss from AV malformations that were not observed before implant. In each patient this disappeared following successful cardiac transplantation.
Impact of vascular resistance on a Continuous-Flow pump
A characteristic of a small, intraventricular continuous-flow pump is its pressure sensitivity, which is easily demonstrated both in vitro and in vivo. Our early animal experiments confirmed the strong correlation we had seen in our in vitro studies [23]. Against a low resistance, the continuous-flow pump can generate high flow; however, it lacks sufficient power to overcome higher resistances. Therefore, it is important to monitor and treat elevated blood pressure after implant. Increased afterload can decrease the contribution of the pump and is dangerous in patients with relatively high pump dependence [24] (Fig 4).
|
We first used the ascending aorta as a site of outflow graft anastomosis in a patient with advanced cardiomyopathy and left main artery occlusion because we wanted to perform a simultaneous bypass at the time of pump implant. We felt that pump function would be unaffected by the site of the outflow graft anastomosis, but we were concerned about the effect of the anastomosis on venous outflow grafts to the coronary arteries. At the time of implantation, we noted that stasis did not occur in the ascending aorta, even if the native aortic valve did not open (Fig 5). Because we were concerned about the possibility of steal from the proximally placed vein grafts, we undertook direct measurement of coronary flow to the three grafts. We found graft flow measurements at the time of implant exhibited satisfactory antegrade coronary graft flow, except at the highest pump speeds (Fig 6). We are currently further assessing the flow characteristics and differences between the two anastomotic outflow graft sites with computerized flow dynamics. We continue to individualize selection for the outflow graft anastomosis and approach to implantation. Considerations of patient size, previous sternotomy, left ventricular dimensions, and degree of coronary artery disease, calcification, or arteriosclerosis of the descending artery are factors that affect the preference of graft anastomotic site.
|
|
|
|
Conclusion |
|---|
|
TopAbstractIntroductionPatients and methodsResultsCommentConclusionAcknowledgmentsDiscussionReferences |
|---|
Experience with new technology such as this pump requires a critical mass of dedicated observers. We believe there needs to be wider use and study of these continuous flow technologies in experienced centers if we are to improve our ability to profile patients who will benefit from this simplified method of cardiac support, which can be implemented with less expense and lower operative risk.
|
Acknowledgments |
|---|
|
TopAbstractIntroductionPatients and methodsResultsCommentConclusionAcknowledgmentsDiscussionReferences |
|---|
|
Discussion |
|---|
|
TopAbstractIntroductionPatients and methodsResultsCommentConclusionAcknowledgmentsDiscussionReferences |
|---|
DR FRAZIER: The only meaningful tests that can be done in this regard are in vivo studies. The Jarvik pump (Jarvik Heart Inc, New York, NY) can pump water indefinitely in the laboratory, so the only relevant question is its durability in the bloodstream. One of our patients, the first to be treated in England, has now had the pump for 2.5 years. He received it in June 2000. Eight other European patients have had the device for more than 1 year. Doctor Jarvik thinks that the bearing, which is the component most likely to undergo eventual failure, should last for 5 to 6 years.
DR HASSAN NEMEH (Chicago, IL): Thank you Dr. Frazier for an informative presentation. What are you doing about prevention of thromboembolism?
DR FRAZIER: First, one must optimize patient selection. For our early patients, who were receiving warfarin, we had a target international normalized ratio (INR) of 1.8 to 1.5, and 2 patients had gastrointestinal bleeding related to an arteriovenous malformation. We later published a report about that complication. It has also been seen in patients with severe aortic stenosis, which will also dampen the pulse pressure. Because of bleeding, 1 patient was supported for 224 days without anticoagulation, and no thromboembolic complications occurred.
Nonetheless, one must optimize function to allow aortic valve opening, particularly when the outlet graft is implanted to the descending aorta. We now prescribe the same anticoagulation regimen for Jarvik patients as for mitral valve recipients, using a target INR of 2.0 to 2.5. The European patients are treated similarly.
DR NEMEH: I believe these pumps are fairly afterload sensitive. Would switching your outflow graft implantation from the descending to the ascending aorta cause a problem in that regard? Are there any special tricks you have to use to avoid kinks in the graft?
DR FRAZIER: No. Technically it's not a problem as far as the implant goes. The ascending aorta involves a greater distance, and I have been surprised by the lack of stasis in the aortic valve and the lack of problems at that level on the echocardiogram.
The situation has been similar with the DeBakey pump, which has had problems with clotting, but not in the ascending aorta. From an engineering standpoint the flow dynamics appear to be more favorable in the ascending aorta.
All the patients in the European destination-therapy group had been outpatients with severe heart failure. We all have such patients. Our transplant waiting list includes 22 outpatients who are receiving inotropic agents, but their heart failure is still compensated, and they are functionally in New York Heart Association class II or III. Such patients are ideally suited for this technology because the pump could serve in its most effective role, that of a true left ventricular assist device. So I believe that the key to avoiding problems with thromboembolism and stasis is more likely to be patient selection than anticoagulation.
DR ALVAN W. ATKINSON (Raleigh, NC): Your comments about patient selection remind me of what my passed away chief, Joe Utley, used to say: "Good surgical treatment, usually the sooner it's applied the better the results.''
And it seems like if we get an end-stage patient this is not the device. And it's just a really great study, and I had one other question.
DR FRAZIER: If you treat the same patients—those who are ICU bound and intubated, receiving intravenous drips and balloon counterpulsation—some of them will survive with the Novacor (Baxter Health Care Corp, Deerfield, IL) or HeartMate (Thoratec Corp, Pleasanton, CA). But I think that the chance of salvaging these patients will be fairly slim with continuous-flow pumps.
DR ATKINSON: One other thing I thought of as you were talking about is its physiology, that perhaps drugs that markedly decrease afterload, perhaps Primacor (Sanofi-Synthelabo Inc, Malvern, PA), or early on until the patient's vasomotor system recovers from their illness, if you might say, might be of a great adjunct, and then ACE inhibitors chronically.
DR FRAZIER: We are trying to initiate a study in which patients who have proved refractory to Primacor will be randomized to receive further medical therapy or implantation of the Jarvik heart. This would still be a high-risk group, but I think that it would be an appropriate one if some residual myocardial function could be demonstrated.
|
References |
|---|
|
TopAbstractIntroductionPatients and methodsResultsCommentConclusionAcknowledgmentsDiscussionReferences |
|---|
This article has been cited by other articles:
|
|
 |
|
  M. Morshuis, A. El-Banayosy, L. Arusoglu, R. Koerfer, R. Hetzer, G. Wieselthaler, A. Pavie, and C. Nojiri European experience of DuraHeartTM magnetically levitated centrifugal left ventricular assist system Eur. J. Cardiothorac. Surg., June 1, 2009; 35(6): 1020 - 1028. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. Loffler, A. Straub, N. Bassler, K. Pernice, F. Beyersdorf, C. Bode, M. P. Siegenthaler, and K. Peter Evaluation of platelet activation in patients supported by the Jarvik 2000* high-rotational speed impeller ventricular assist device. J. Thorac. Cardiovasc. Surg., March 1, 2009; 137(3): 736 - 741. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
F. Nicolini and T. Gherli Alternatives to transplantation in the surgical therapy for heart failure Eur. J. Cardiothorac. Surg., February 1, 2009; 35(2): 214 - 228. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. John, F. Kamdar, K. Liao, M. Colvin-Adams, L. Miller, L. Joyce, and A. Boyle Low thromboembolic risk for patients with the Heartmate II left ventricular assist device. J. Thorac. Cardiovasc. Surg., November 1, 2008; 136(5): 1318 - 1323. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 R. John, F. Kamdar, K. Liao, M. Colvin-Adams, A. Boyle, and L. Joyce Improved Survival and Decreasing Incidence of Adverse Events With the HeartMate II Left Ventricular Assist Device as Bridge-to-Transplant Therapy Ann. Thorac. Surg., October 1, 2008; 86(4): 1227 - 1235. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
N. D. Patel, E. S. Weiss, J. Schaffer, S. L. Ullrich, D. C. Rivard, A. S. Shah, S. D. Russell, and J. V. Conte Right Heart Dysfunction After Left Ventricular Assist Device Implantation: A Comparison of the Pulsatile HeartMate I and Axial-Flow HeartMate II Devices Ann. Thorac. Surg., September 1, 2008; 86(3): 832 - 840. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 L. W. Miller, F. D. Pagani, S. D. Russell, R. John, A. J. Boyle, K. D. Aaronson, J. V. Conte, Y. Naka, D. Mancini, R. M. Delgado, et al. Use of a Continuous-Flow Device in Patients Awaiting Heart Transplantation N. Engl. J. Med., August 30, 2007; 357(9): 885 - 896. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. D. Feller, E. N. Sorensen, M. Haddad, R. N. Pierson, F. L. Johnson, J. M. Brown, and B. P. Griffith Clinical Outcomes Are Similar in Pulsatile and Nonpulsatile Left Ventricular Assist Device Recipients Ann. Thorac. Surg., March 1, 2007; 83(3): 1082 - 1088. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. Takeda, G. Matsumiya, H. Takano, M. Koh, K. Iwata, and Y. Sawa Unusual thrombus formation in the aorta after apicoaortic conduit for severe aortic stenosis J. Thorac. Cardiovasc. Surg., July 1, 2006; 132(1): 155 - 156. [Full Text] [PDF]
|
|
|
|
|
|
M. P. Siegenthaler, J. Martin, R. Gutwald, R. Bahr, S. Westaby, R. Schmelzeisen, and F. Beyersdorf Anterior Approach to Implant the Jarvik 2000 With Retroauricular Power Supply Ann. Thorac. Surg., August 1, 2005; 80(2): 745 - 747. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. P. Siegenthaler, S. Westaby, O.H. Frazier, J. Martin, A. Banning, D. Robson, J. Pepper, P. Poole-Wilson, and F. Beyersdorf Advanced heart failure: feasibility study of long-term continuous axial flow pump support Eur. Heart J., May 2, 2005; 26(10): 1031 - 1038. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. J. Goldstein, M. Zucker, L. Arroyo, D. Baran, P. M. McCarthy, M. Loebe, and G. P. Noon Safety and feasibility trial of the MicroMed DeBakey ventricular assist device as a bridge to transplantation J. Am. Coll. Cardiol., March 15, 2005; 45(6): 962 - 963. [Full Text] [PDF]
|
|
|
|
|
|
S. P. Salzberg, M. L. Lachat, K. von Harbou, G. Zund, and M. I. Turina Normalization of high pulmonary vascular resistance with LVAD support in heart transplantation candidates Eur. J. Cardiothorac. Surg., February 1, 2005; 27(2): 222 - 225. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. A. Fox and N. A. Nussmeier Does Gender Influence the Likelihood or Types of Complications Following Cardiac Surgery? Seminars in Cardiothoracic and Vascular Anesthesia, December 1, 2004; 8(4): 283 - 295. [Abstract] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| ANN THORAC SURG | ASIAN CARDIOVASC THORAC ANN | EUR J CARDIOTHORAC SURG |
| J THORAC CARDIOVASC SURG | ICVTS | ALL CTSNet JOURNALS |
= left coronary flow. (rpm = revolutions per minute.)