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Ann Thorac Surg 2008;86:832-840. doi:10.1016/j.athoracsur.2008.05.016
© 2008 The Society of Thoracic Surgeons
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Right arrow Mechanical Circulatory Assistance

Original Articles: Adult Cardiac

Right Heart Dysfunction After Left Ventricular Assist Device Implantation: A Comparison of the Pulsatile HeartMate I and Axial-Flow HeartMate II Devices

Nishant D. Patel, BAa, Eric S. Weiss, MDa, Justin Schaffer, MSa, Susan L. Ullrich, RNa, Dennis C. Rivard, MAa, Ashish S. Shah, MDa, Stuart D. Russell, MDb, John V. Conte, MD*

a Division of Cardiac Surgery, The Johns Hopkins Medical Institutions, Baltimore, Maryland
b Division of Cardiology, The Johns Hopkins Medical Institutions, Baltimore, Maryland

Accepted for publication May 5, 2008.

Abbreviations and Acronyms CHF = congestive heart failure; CVP = central venous pressure; LVAD = left ventricular assist device; mPAP = mean pulmonary artery pressure; NYHA = New York heart association; PCWP = pulmonary capillary wedge pressure; REMATCH = Randomized Evaluation of Mechanical Assistance for the Treatment of Congestive Heart Failure; RHD = right heart dysfunction; RVAD = right ventricular assist device; RVSWI = right ventricular stroke work index

* Address correspondence to Dr Conte, Division of Cardiac Surgery, Johns Hopkins Medical Institutions, Blalock 618, 600 N Wolfe St, Baltimore, MD 21287 (Email: jconte{at}csurg.jhmi.jhu.edu).

Presented at the Forty-fourth Annual Meeting of The Society of Thoracic Surgeons, Fort Lauderdale, FL, Jan 28–30, 2008.


Drs Conte and Russell disclose that they have a financial relationship with Thoratec Corp.

 

   Abstract
Top
 Abstract
Introduction
 Material and Methods
 Results
 Comment
 Discussion
 Acknowledgments
 References
 
Background: Right heart dysfunction confers significant morbidity and mortality after left ventricular assist device implantation and historically occurs in as many as a third of patients. It is unknown whether newer axial flow pumps have a different impact on postimplant right heart dysfunction. We compared the incidence of right heart dysfunction after implantation of the pulsatile HeartMate I (XVE) and the continuous flow HeartMate II left ventricular assist device.

Methods: We retrospectively reviewed patients who underwent HeartMate I or HeartMate II implantation between June 2000 and March 2007. Right heart dysfunction was defined as inotropic/vasodilator support for 14 or more consecutive days or the need for a right ventricular assist device, or both.

Results: Seventy-seven patients underwent HeartMate implantation; 43 received a HeartMate I and 34 received a HeartMate II, for a mean left ventricular assist device support time of 202 and 160 days, respectively. Operative mortality was lower for HeartMate II patients (28% versus 15%; p = 0.26). The HeartMate II patients had lower preoperative right ventricular stroke work index. Pulmonary vascular resistance index, right ventricular stroke work index, and pulmonary and right atrial pressures improved and were similar between groups postoperatively. Overall, right heart dysfunction developed in 35% of HeartMate I patients (15 of 43) and 41% of HeartMate II patients (14 of 34; p = 0.63). Fewer HeartMate II patients (2) than HeartMate I patients (5) required 7 or more days of epinephrine, whereas more HeartMate II patients (7) than HeartMate I patients (5) required 7 or more days of milrinone. Six HeartMate I and 3 HeartMate II patients required right ventricular assist device implantation for right heart failure. Survival was similar (p = 0.7) between groups at, respectively, 3 (63% versus 62%), 6 (58% versus 58%), and 12 months (49% versus 48%).

Conclusions: Right heart dysfunction is a persistent clinical problem after left ventricular assist device placement. We report the first study comparing the incidence of right heart dysfunction after HeartMate I versus HeartMate II implantation. Although the incidence of right heart dysfunction was similar, fewer HeartMate II patients required right ventricular assist device placement and fewer required pure inotropic support for right heart failure.

Nearly 5 million Americans suffer from congestive heart failure (CHF) [1]. With 550,000 new cases diagnosed annually and cost estimates exceeding $10 billion, CHF continues to be a significant public health concern [1, 2]. Survival remains poor, with a 1-year mortality rate greater than 50% for patients with severe CHF [3].

Survival, quality of life, and functional capacity are limited for patients with CHF despite significant advancements in medical therapy. Currently, cardiac transplantation is the gold standard for the treatment of CHF, but it is donor limited, requires immunosupression therapy, and has many exclusions to candidacy.

Left ventricular assist devices (LVAD) have been shown to successfully support patients awaiting cardiac transplantation [4–12]. The Randomized Evaluation of Mechanical Assistance for the Treatment of Congestive Heart Failure (REMATCH) trial showed that LVADs may improve survival and quality of life for those with severe end-stage CHF who are not candidates for cardiac transplantation [13, 14]. The REMATCH trial demonstrated a 48% reduction in the risk of death for LVAD recipients versus patients receiving optimal medical therapy despite using an LVAD with limited durability.

Right heart dysfunction (RHD) is a concern after LVAD implantation and occurs historically in as many as one third of patients [15]. First-generation pulsatile devices, such as the HeartMate XVE, have been causally related to the incidence of RHD owing to the mechanical effects of left ventricular unloading [15]. The impact of recently developed axial flow [16–19] LVADs on right heart function is unknown. The HeartMate II LVAD (Thoratec Corporation, Pleasanton, California) is a promising new axial-flow pump that is currently in clinical trials in the United States (Fig 1). Complete left ventricular unloading is avoided with this device and other second-generation axial flow pumps. Our sense and that of other investigators is that there is less RHD with the axial flow pumps owing to maintenance of left ventricular end-diastolic volume, maintained septal position, and preservation of right ventricular mechanics. We began using the HeartMate II in January of 2005 and sought to compare the incidence of RHD and right heart failure after implantation with the HeartMate II versus HeartMate I LVAD.


Figure 1
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  		Fig 1. (Left) The HeartMate II and (right) the HeartMate I (XVE) left ventricular assist devices.

 

   Material and Methods
Top
 Abstract
 Introduction
 Material and Methods
Results
 Comment
 Discussion
 Acknowledgments
 References
 
Study Design
We conducted a retrospective review of all patients who underwent either HeartMate II or HeartMate I (XVE) LVAD implantation at our institution from June 2000 to March 2007 after Institutional Review Board approval. Individual waiver for consent was granted. For analysis, patients were grouped into those who underwent HeartMate II implantation versus those who had HeartMate I implantation. Relevant baseline, operative, and postoperative data were collected. Hemodynamic data included pulmonary capillary wedge pressure (PCWP), mean pulmonary artery pressure (mPAP), central venous pressure (CVP), cardiac index, pulmonary vascular resistance index, and right ventricular stroke work index (RVSWI) collected preoperatively and 1, 3, and 6 months after LVAD implantation. Study endpoints included survival, the incidence of right heart dysfunction, defined as the need for inotropes or vasodilators for 14 or more consecutive days, or the need for a right ventricular assist device (RVAD).

Statistical Analysis
Statistical analyses were performed using SPSS 12.0 software (SPSS, Chicago, Illinois). All data are presented as HeartMate II versus HeartMate I and as mean ± SD unless otherwise noted. Fisher's exact test and t test were used for qualitative and quantitative variable analyses, respectively. Kaplan-Meier and log-rank analyses were performed to compare survival for HeartMate II versus HeartMate I patients. We conducted Cox proportional hazards regression modeling to assess for predictors of mortality and logistic regression analysis to assess for predictors of right heart dysfunction.

Operative Technique
Patients receiving the HeartMate II LVAD underwent median sternotomy. The outflow graft was anastomosed to the ascending aorta without bypass whenever possible. After the institution of cardiopulmonary bypass, an apical ventriculotomy was made and the inflow cannula was placed in the left ventricular apex. The pump was then activated; after deairing, patients were weaned from cardiopulmonary bypass. Our patients routinely come off cardiopulmonary bypass on epinephrine, milrinone, and inhaled nitric oxide in various combinations. The continuation of inotropes was made based on clinical interpretation of the hemodynamic data. Those patients requiring protracted inotropes typically had inotrope-dependent LVAD flow as well as echocardiographic evidence of right ventricular dysfunction.

The HeartMate I LVAD is implanted in a similar fashion. HeartMate I patients were weaned off cardiopulmonary bypass in a fixed rate mode, as recommended by the manufacturer, and once stable off cardiopulmonary bypass, switched to automatic mode. Patients with severe tricuspid regurgitation underwent concomitant tricuspid annuloplasty. This decision was made based on the preoperative echocardiogram in most cases. In some patients, intraoperative transesophageal echocardiograms that showed significant worsening of tricuspid regurgitation prompted repair. Tricuspid repair was routinely performed before apical ventriculotomy.


   Results
Top
 Abstract
 Introduction
 Material and Methods
 Results
Comment
 Discussion
 Acknowledgments
 References
 
During the study period, 77 patients underwent implantation with a HeartMate LVAD. Since January 2005, 34 patients have received a HeartMate II LVAD. The remaining 43 patients in this study received a HeartMate I LVAD between June 2000 and October 2006. Mean LVAD support time was 160.5 ± 173.4 days for the HeartMate II group and 202.3 ± 258.9 days for the HeartMate I group. Baseline clinical characteristics were similar between groups and are shown in Table 1. An ischemic cause of CHF occurred in approximately one third of patients in each group (p = 1.00). All HeartMate II patients and 97.6% of HeartMate I patients (42 of 43) were in preoperative New York Heart Association (NYHA) class IV.


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  		Table 1 Baseline Characteristics
 
Baseline hemodynamic indices, renal and hepatic function, and hematologic data are shown in Table 2 and were similar between HeartMate II and I patients. Preoperative RVSWI was significantly lower for the HeartMate II group (5.7 versus 8.2 g*m/m2; p = 0.002), indicating worse right heart function in the HeartMate II versus HeartMate I group.


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  		Table 2 Baseline Hemodynamics, Renal and Hepatic Function, and Hematologic Data
 
Operative Data
Mean cardiopulmonary bypass time was 76.7 ± 34.9 minutes for the HeartMate II group and 96.2 ± 37.5 minutes for the HeartMate I group (p = 0.04). Twenty-nine percent of HeartMate II patients (10 of 34) and 4.7% of HeartMate I patients (2 of 43) underwent concomitant tricuspid valve annuloplasty (p = 0.004).

Hemodynamics
Changes in hemodynamic indices while on mechanical circulatory support with either the HeartMate II or HeartMate I LVAD are shown in Table 3. Mean PCWP, mPAP, and cardiac index significantly improved postoperatively for the HeartMate II group, whereas the mean CVP and pulmonary vascular resistance index trended toward improvement. For the HeartMate I group, mean PCWP, mPAP, CVP, and cardiac index significantly improved postoperatively; pulmonary vascular resistance index trended toward improvement, but did not reach statistical significance. When comparing HeartMate II and HeartMate I patients, both groups had similar postoperative PCWP, mPAP, and CVP at 1, 3, and 6 months postoperatively (Fig 2). Postoperative RVSWI was also similar between groups at 6 months.


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  		Table 3 Preoperative and Postoperative Hemodynamic Indexes
 

Figure 2
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  		Fig 2. Preoperative and postoperative hemodynamic data for HeartMate I (solid lines) and HeartMate II (dashed lines). (CVP = central venous pressure; mPAP = mean pulmonary artery pressure; PCWP = pulmonary capillary wedge pressure.)

 
Inotropic/Vasodilator Requirement and RHD
Right heart dysfunction, defined as 14 consecutive days of inotropic or vasodilator support or the need for a right ventricular assist device (RVAD), was similar between groups (41.2% versus 34.9%; p = 0.63). Three HeartMate II patients and 6 HeartMate I patients required a RVAD for right heart failure (p = 0.72).

We assessed postoperative inotropic and vasodilator requirements for each group, including the number of consecutive days on epinephrine and milrinone, and found no differences in the total amount of inotropes and vasodilators used. The HeartMate II group did have fewer patients requiring 7 or more consecutive days of epinephrine, although the HeartMate II group had more patients requiring 7 or more days of milrinone (Table 4).


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  		Table 4 Postoperative Consecutive Days Requiring Inotropes for HeartMate I and HeartMate II Patients
 
Renal and Hepatic Function
Serum markers of renal and hepatic function significantly decreased for both groups postoperatively (Table 5). Serum creatinine, total bilirubin, alanine aminotransferase, and aspartate aminotransferase levels trended toward improvement in the HeartMate II group, but were not quite statistically significant. Serum creatinine, blood urea nitrogen, alanine aminotransferase, and aspartate aminotransferase levels did significantly decrease postoperatively in the HeartMate I group (Table 5). All serum markers were similar at 1, 3, and 6 months postoperatively (Fig 3). Blood urea nitrogen (p = 0.27), alanine aminotransferase (p = 0.83), and aspartate aminotransferase (p = 0.73) were also similar between groups at 6 months postoperatively.


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  		Table 5 Preoperative and Postoperative Renal and Hepatic Data
 

Figure 3
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  		Fig 3. Preoperative and postoperative serum creatinine and total bilirubin for HeartMate I (solid lines) and HeartMate II (dashed lines).

 
Length-of-Stay, Complications, and Survival
Total length of stay was 58.4 ± 37.3 days for the HeartMate II group and 63.4 ± 56.8 days for the HeartMate I group (p = 0.66). Postoperative length of stay was 48.8 ± 32.7 days for the HeartMate II group and 51.0 ± 54.3 days for the HeartMate I group (p = 0.82). Postoperative data are listed in Table 6. HeartMate II patients required less blood replacement therapy and fewer required reoperation for bleeding than HeartMate I patients.


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  		Table 6 Postoperative Data
 
Thirty-day mortality was 25.3% (5 of 33) and 27.9% (12 of 43) for the HeartMate II and HeartMate I groups, respectively (p = 0.15). Late mortality was 27.3% (9 of 33) for the HeartMate II group and 32.6% (14 of 43) for the HeartMate I group, which was not a statistically significant difference (p = 0.61). As shown in Figure 4, Kaplan-Meier survival, including hospital deaths, was 50% at 1 year for both groups; 2-year survival was 44% and 48% for the HeartMate I and II groups, respectively (p = 0.70).


Figure 4
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  		Fig 4. Kaplan-Meier survival, including hospital deaths, for HeartMate I (HMI [solid line]) and HeartMate II (HMII [dashed line]) patients.

 
When analyzing all patients in this series for risk factors for mortality, increasing age (hazard ratio [HR] 1.07; 95% confidence interval [CI]: 1.02 to 1.12; p = 0.004) and lower preoperative RVSWI (HR 0.75; 95% CI: 0.57 to 0.98; p = 0.03) were associated with mortality. The lone marker for right heart dysfunction was preoperative intra-aortic balloon pump counterpulsation (odds ratio [OR] 6.21; 95% CI: 1.01-38.0; p = 0.04). Variables included in the analyses were age, sex, race, type of HeartMate device, preoperative inotropes, cause of CHF, diabetes mellitus, cardiogenic shock, chronic obstructive pulmonary disease, previous myocardial infarction, body mass index, preoperative intra-aortic balloon pump, preoperative creatinine, preoperative PCWP, preoperative mPAP, preoperative cardiac index, preoperative pulmonary vascular resistance index, preoperative CVP, and preoperative RVSWI. The type of HeartMate device was not associated with mortality (HR 0.3; 95% CI: 0.1 to 1.0; p = 0.06) or right heart dysfunction (OR 1.3; 95% CI: 0.36 to 5.12; p = 0.64) in our models.


   Comment
Top
 Abstract
 Introduction
 Material and Methods
 Results
 Comment
Discussion
 Acknowledgments
 References
 
Many studies have successfully shown that LVADs are an excellent option for patients with end-stage CHF and for those awaiting cardiac transplantation, with significant improvements in survival and quality of life [13, 14, 20–23]. The REMATCH trial has shown that LVAD therapy improves survival in end-stage heart failure patients who are not transplant candidates compared with medically managed patients [13, 14]. The two most frequent causes of death in the LVAD group were sepsis and device failure [24]. Nearly 50% of the device malfunctions involved implantable components, the most common of which was inflow conduit malfunctions resulting in inflow valve incompetence. The newer axial-flow LVADs have been designed in an effort to minimize operative risk, improve durability, and lower the risk of device-related adverse events, in part by reducing the number of moving parts in the device [16–19].

The HeartMate II, developed by Thoratec Corporation, is a continuous, axial-flow LVAD with a spinning rotor as its lone moving part, an inflow cannula with a sintered titanium surface, an impeller powered by an electromagnetic motor, and a single driveline that exits the abdomen [18, 19, 25–28]. Early results have been excellent in the bridge to transplant population [28].

Right heart dysfunction is a concern after LVAD implantation and contributes significantly to postoperative morbidity and mortality. In a study of 108 patients undergoing HeartMate I implantation, Dang and colleagues [15] reported that 38.9%, or 42 patients, had right heart failure postoperatively. Of the 42 patients with right heart failure, 14 required a RVAD. The authors found that female patients were more likely to develop right heart failure than male patients, and patients with right heart failure had a higher early mortality rate, longer intensive care unit length of stay, higher rates of reoperation for bleeding, and a greater incidence of renal failure than those who did not have right heart failure. Furthermore, the authors found that intraoperative CVP was a significant predictor of postoperative right heart failure.

Many theories as to the etiology of RHD have been proposed [29–33]. Experimental models have been used to try and discern the genesis of LVAD-associated RHD. Omoto and colleagues [29] found a Frank-Starling relation for the right ventricular free wall in an isolated right heart canine model. The authors demonstrated a linear relationship between right ventricular systolic peak pressure and end-diastolic length or end-diastolic pressure. Moon and coworkers [30] have shown a global decrease in right ventricular systolic function with a concomitant increase in right ventricular end-diastolic volume to maintain right ventricular output. Farrar and colleagues [31] in an early work found reduced right ventricular contraction in normal dogs during LVAD support. Elbeery and colleagues [32], on the other hand, observed that right ventricular function during LVAD support was maintained and the systolic interaction with the left ventricle was of minimal consequence in the maintenance of right heart function. Finally, an earlier work from Miyamoto and colleagues [33] showed that increases in the amount of left ventricular unloading led to incremental decreases in the derivative of right ventricular pressure (right ventricular dP/dt), effectively reducing right ventricular function.

A valid criticism of these experimental studies is that they are performed in normal hearts and not hearts in animals with CHF. The finding of increased right ventricular end-diastolic pressure experimentally, however, does correlate with what is seen clinically in those hearts with RHD after LVAD implantation. They are enlarged, hypocontractile, and need an increased preload to maintain adequate LVAD flows. Many of the LVAD models used in these animal experiments are pulsatile pumps, which do not necessarily reflect what occurs with continuous flow devices.

In our study, 14 HeartMate II patients and 15 HeartMate I patients met our definition of right heart dysfunction postoperatively. The most significant finding was that 3 HeartMate II and 6 HeartMate I patients underwent RVAD placement for right heart failure. While the need for RVAD support was lower in the HeartMate II group, this did not reach statistical significance. The length of inotrope and vasodilator use is a much softer endpoint. Our more recent tendency to leave patients on vasodilators until diuresed may bias the data. The HeartMate II patients did require less pure inotropic support and more vasodilators than HeartMate I patients. A larger patient cohort and longer follow-up may demonstrate true differences in the need for RVAD and inotropic support after HeartMate II implantation.

The HeartMate I device mechanically unloads the left ventricle, which may result in bowing of the interventricular septum away from the right ventricle. Bulging of the septum into the left ventricle may reduce the efficiency of right ventricular contraction by destabilizing the fulcrum upon which the right ventricle contracts (Fig 5) [15]. Moreover, the right ventricle may receive a venous return beyond its capacity owing to the LVAD's effective forward flow through the systemic circulation, resulting in right ventricular dysfunction [34]. Maintaining the septal midline position requires maintenance of some left ventricular volume. This results in less than maximal LVAD flow, which prevents overcirculation that could overwhelm the functional capacity of the right ventricle.


Figure 5
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  		Fig 5. Echocardiogram showing septal bowing into the left ventricle after HeartMate XVE implantation.

 
In our early experience with the HeartMate II LVAD, we became more aggressive with performing a concomitant tricuspid annuloplasty, and our current policy is to repair the valve in patients with moderate or worse tricuspid regurgitation. That may be important, as experimental evidence suggests diminished right ventricular function requires an increased right ventricular end-diastolic pressure to maintain comparable forward flow. This increased right ventricular end-diastolic pressure and right ventricular end-diastolic dimension can cause tricuspid valve chordal tethering and increase tricuspid regurgitation. Tricuspid valve repair can correct this abnormality and help maintain flow.

Our early clinical impression is that there is less RHD after HeartMate II implantation. We do find that HeartMate II patients come off bypass easier, require lower peak doses of inotropes, and recover relatively faster than their HeartMate I counterparts. When coming off cardiopulmonary bypass, we monitor the position of the septum and attempt to maintain enough left ventricular volume to keep the septum in a midline position, which may lead to less RHD. On logistic regression analysis, the only predictor of RHD was preoperative intra-aortic balloon pump counterpulsation, which demonstrates that preoperative acuity is a predictor of right heart dysfunction. Although preoperative hemodynamic indices were not predictive of RHD in our model, we agree with Dang and colleagues [15] that perhaps the best predictor of postimplant RHD is preoperative RHD.

The implications of continuous versus pulsatile blood flow are currently unknown and have been a matter of significant debate [35]. While some argued that pulse-pressure is necessary for maintaining the integrity of the circulation and end-organ function, others argue that nonpulsatile flow allows for normal end-organ function. Many have used animal studies of nonpulsatile flow to address the issue [35–41], but few studies are available that describe outcomes in humans supported by nonpulsatile LVADs. Our early results indicate that renal and hepatic function after HeartMate II implantation is similar to the HeartMate I group at 1, 3, and 6 months after surgery.

Recent years have seen considerable advancement in axial-flow LVADs with the development of the Jarvik 2000 (Jarvik Heart, New York, New York), the MicroMed DeBakey LVAD (MicroMed, Houston, Texas), the HeartMate II LVAD, and others. We have shown that the HeartMate II continuous, axial-flow LVAD adequately supports the systemic circulation and arguably demonstrates a lower incidence of right heart dysfunction. Nevertheless, longer follow-up is necessary to determine if the HeartMate II LVAD can continue to minimize right heart dysfunction and lower the need for RVAD support versus older generation pulsatile devices.


   Discussion
Top
 Abstract
 Introduction
 Material and Methods
 Results
 Comment
 Discussion
Acknowledgments
 References
 
DR EVGENIJ POTAPOV (Berlin, Germany): This is a very important study because there is a fairy tale about an increased incidence of right heart failure in patients with axial flow pumps. I have some questions.

You showed that there are no significant differences in right heart dysfunction between the two groups. You showed also that there are no significant differences in need of right ventricular assist devices. And you reported that in the first period of your study you used mostly pulsatile pumps and in the second period of your study you used mostly axial flow pumps. My question is, do you think that this fact and the improvement in the selection of patients over time may contribute to a decrease or to the trend toward a decrease of right heart failure in your study?

MR PATEL: Thank you very much for that important question. We agree with what you are saying. We believe that improvement in patient selection has lowered our incidence of right heart failure.

DR ROBERT F. KORMOS (Pittsburgh, PA): Nice work, very nicely presented, and I think it emphasizes the progression of understanding of managing the right ventricle very nicely across the board, and I think your comments about patient selection probably are relevant. My question relates to the methodology that you used to try and prevent right heart dysfunction, which essentially is to not try to run the device at the highest possible output that you can achieve but prevent septal shift. I agree that is an important step. But do you think this is achievable with the pulsatile devices, because my sense is that we are kind of doing that already with the pulsatile systems; we are doing the same strategy. So is it the strategy or the type of device that will impact on prevention of right ventricular dysfunction?

MR PATEL: That is a great question, probably better answered by Dr Conte.

DR CONTE (Baltimore, MD): Bob, I think you and I have dealt with this for a while and I don't think we know the right answer to that. Certainly the only way we can deal with the pulsatile flow pumps is to turn them down into a fixed rate mode, and certainly we have done that. I think one of the problems that we got into with the pulsatile flow pumps that led to some of the right ventricular dysfunction problems was the fact that we let the left ventricle become unloaded and we flew at flows much higher than the right ventricle could stand early on, and we caused a lot of the right ventricular dysfunction, because I don't think we appreciated the fact that we were overcirculating the right ventricle early on. And as we saw, if we can get those people through that they did fine long term, and I don't really think the right ventricle has proved to be a nonissue long term once we get them through that first 2 or 3 days. But I do think that we cause a lot of our own problems by overflowing the right ventricle early on.

DR JOSEPH C. CLEVELAND (Denver, CO): Again, I congratulate Mr Patel and Dr Conte on a nice series of patients. Quickly, realizing these are historical controls, one other thing to look at I think, based upon our perspective of implanting the HeartMate II, is the bleeding less? Did you control for blood use in the two groups to see if there was a difference, because I think magnitude of perioperative bleeding is a contributor to right heart dysfunction. We seem to give less blood with the HeartMate II, and I think that may be something to consider. Is that something you looked at as well?

MR PATEL: No, that is not something that we included in our analysis. However, we are currently collecting those data and agree that including the use of blood products is important in analyzing right heart dysfunction after LVAD implantation.


   Acknowledgments
Top
 Abstract
 Introduction
 Material and Methods
 Results
 Comment
 Discussion
 Acknowledgments
References
 
This study was supported in part by the Mildred and Carmont Blitz Cardiac Research Fund. Doctor Weiss is an Irene Piccinini Investigator in Cardiac Surgery.


   References
Top
 Abstract
 Introduction
 Material and Methods
 Results
 Comment
 Discussion
 Acknowledgments
 References
 

  1. 2001 Heart and stroke statistical update. Dallas: American Heart Association; 2000.
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