Improved mortality and rehabilitation of transplant candidates treated with a long-term implantable left ventricular assist system

Patient selection for the use of ventricular assist devices as a bridge to transplantation

Patient selection is a critical factor in the outcome associated with the use of mechanical assist devices for the treatment of refractory heart failure/shock. Numerous risk factors impact on the outcome, many of which can be identified and treated before device surgery. This manuscript reviews all the risk factors that have been identified to date and the use of composite risk scores to predict outcome.

The future of mechanical circulatory support

Heart failure is one of the most important causes of morbidity and mortality in adults and the elderly. In the United States, an estimated 5 million persons already have heart failure, and more than 500,000 new cases are being diagnosed each year [ 1]. Today, cardiovascular physicians can choose from a wide range of mechanical circulatory systems, depending on the desired degree of support, length of support, extent of postoperative mobility and other factors. This article describes the growing problem of heart failure and the future prospects for patients with heart disease. It discusses current mechanical circulatory support devices and their changing applications, newer devices still in the experimental stages, and some hurdles to the use of mechanical circulatory support.

Successful experience in bridging patients to heart transplantation with the MicroMed DeBakey ventricular assist device

BACKGROUND

Pulsatile left ventricular assist devices are used with increasing frequency to bridge patients with end-stage heart failure to heart transplantation (HTx). Implantation of pulsatile devices is a cumbersome surgical procedure that is associated with major complications, such as bleeding, thromboembolism, and infection. Recently, a continuous axial flow left ventricular assist device (DeBakey ventricular assist device) has been introduced with the goal of reducing the incidence of major complications.

METHODS

We reviewed our experience with 11 patients who received a DeBakey ventricular assist device axial flow pump for bridge to HTx from April 2000 through November 2001.

RESULTS

Two patients (18.2%) died of multiple-organ failure while on left ventricular assist device support. Bleeding requiring thoracotomy occurred in 2 patients (18.2%). One patient had a minor neurologic event, and one patient developed left ventricular assist device thrombosis, which was successfully treated without pump exchange. Renal failure developed in 1 patient and hepatic dysfunction in 2 patients. There were no instances of right heart failure. No device, pocket, or drive-line infections occurred. Nine patients (9 of 11, 81.8%) had HTx within 51 +/- 49 days (range, 11 to 141 days) after left ventricular assist device implant. One patient died 29 days after HTx because of acute rejection.

CONCLUSIONS

The continuous axial flow DeBakey ventricular assist device had reliable features, including a high rate of bridge to HTx. This device had low complication and system failure rates. We consider the DeBakey ventricular assist device a favorable alternative to pulsatile heart assist devices as a bridge to HTx.

Left ventricular assist devices as bridge to heart transplantation: The Niguarda Experience

BACKGROUND

Congestive heart failure is the leading cause of death in Western countries. Heart transplantation currently is the only accepted therapy for patients with end-stage heart failure, but the supply of donor hearts is inadequate, and different mechanical circulatory support systems have been investigated as bridges to heart transplant.

METHODS

Since April 1992, 53 patients (47 men, 6 women, aged 12 to 61 years) received left ventricle mechanical circulatory support as bridge to heart transplant. The two principal devices used were: the Novacor LVAS in 31 patients and the DeBakey VAD in 11 patients.

RESULTS

All patients survived the operation. Mean duration of LVAD support was 2.8 +/- 5.6 months. Thirty-seven patients (71.1%) underwent heart transplantation. Twelve major bleeding episodes occurred in nine patients (16.9%). Globally, major and minor neurologic events occurred in 13 patients (24.5%). Ten patients (19.9%) assisted with the Novacor Wearable LVAS device were discharged at home while waiting for heart transplant (HTx). The mean follow-up of the 34 discharged transplanted patients was 45.3 +/- 37 months. Actuarial survival of transplanted patients while on LVAD was 91.0 +/- 4.9% and 83.4 +/- 8.5% at 1 and 5 years, respectively. No differences in post-transplant long-term survival and rejection and allograft vasculopathy occurred between patients transplanted with or without LVAD implanted.

CONCLUSIONS

LVAD therapy proved to be effective in bridging patients with end-stage heart failure to HTx. While on LVAD support, patients assisted with implantable wearable devices could be discharged at home, ameliorating their quality of life. The excellent survival rate after HTx is concomitant with a low incidence of rejection and cardiac allograft vasculopathy.

Outpatients on mechanical circulatory support

BACKGROUND

As waiting periods for heart transplantation have lengthened, the application of long-term mechanical circulatory support (MCS) has become more common in patients presenting with cardiogenic shock. Anticipating increased long-term MCS, a policy to discharge patients home has been instituted. This study compares the results of outpatient on MCS to a group of patients remaining hospitalized.

METHODS

We report our 10-year experience with 108 patients on MCS, who were supported for more than 3 months. Group A consisted of 38 patients (25 Novacor, 13 Berlin Heart) who underwent assist implantation from 1996 to 2001. They had a mean support time of 454 days (range 100 to 1074 days) and spent a mean of 326 days (range 20 to 769 days) at home. Group B consisted of 70 patients (24 Novacor, 46 Berlin Heart) who underwent assist implantation between 1991 and 2000. They had a mean support time of 234 days (range 95 to 795 days) and were not discharged. The patients were monitored for complications, hospital readmissions, and causes of death including infections and thromboembolic and bleeding events during the MCS time.

RESULTS

Group A total mortality was 16% (6/38). Two patients died from cerebral embolism, one from cerebral hemorrhage, two from systemic infection, and one from multiorgan failure. Thirty-two patients (84%) required 95 readmissions to the hospital due to cerebral embolism (n = 9), bleeding (n = 1), wound infections (n = 23), coagulation disorder (n = 13) for heart transplantation (n = 5), and (n = 44). In group B the mortality was 43% (30/70) for noncardiac reasons and thus significant higher (p = 0.004, chi2 test). Causes of death were cerebral embolism (n = 5), cerebral hemorrhage (n = 7), systemic infection (n = 14, significantly higher, p = 0.04, chi2 test), and multiorgan failure (n = 4).

CONCLUSIONS

Our experience demonstrates that MCS can be used in outpatients without increased mortality and with an acceptable rate of readmissions (2.8/patient). It ensures the survival of the patient, enables recovery from multiorgan failure, and offers an acceptable quality of life.

Change in quality of life from before to after discharge following left ventricular assist device implantation

BACKGROUND

Quality of life (QOL) outcomes after left ventricular assist device (LVAD) implantation from before to after hospital discharge have been examined only in a very small sample of patients. The purposes of this study are to describe change in QOL from before to after hospital discharge in LVAD patients and to determine whether being discharged with an LVAD predicts better QOL than being hospitalized with an LVAD.

METHODS

A non-random sample of 62 LVAD patients (approximately 50 years old, male, white, married, fairly well-educated) completed self-report questionnaires at >or=2 timepoints post-implant. The questionnaires (Quality of Life Index, Rating Question Form, Heart Failure Symptom Checklist, Sickness Impact Profile, LVAD Stressor Scale, Jalowiec Coping Scale), which were collated into booklets, had acceptable reliability and validity. Longitudinal analyses were performed in 2 steps using 1-sample t-tests and linear mixed effects modeling.

RESULTS

Perception of QOL and health status were fairly good both before and after discharge of LVAD patients. Discharge predicted increased satisfaction with socioeconomic areas of life; decreased overall and psychologic stress and stress related to family and friends, self-care and work/school/finances; and decreased physical and self-care disability.

CONCLUSIONS

QOL outcomes improved from before to after hospital discharge in LVAD patients awaiting heart transplantation. As LVADs potentially become available as destination therapy, in addition to being successful bridges to heart transplantation, QOL outcomes will become more important to study.

Severe renal dysfunction complicating cardiogenic shock is not a contraindication to mechanical support as a bridge to cardiac transplantation

OBJECTIVES

This study investigated outcomes in patients with cardiogenic shock and severe renal dysfunction treated with ventricular assist devices (VAD) as a bridge to cardiac transplantation.

BACKGROUND

Previous reports have documented poor survival in patients with cardiogenic shock and severe renal dysfunction treated with VAD.

METHODS

We surveyed 215 consecutive patients who received a VAD from 1992 to 2000 and selected patients who had a serum creatinine > or =3.0 mg/dl at the time of VAD placement. Demographic, laboratory, and clinical outcome data were collected.

RESULTS

Eighteen patients met the inclusion criteria. Mean serum creatinine at the time of VAD placement was 4.0 +/- 0.7 mg/dl (range 3.0 to 5.2 mg/dl). Seven patients required temporary renal support with continuous venovenous hemodialysis (CVVHD). Eleven patients underwent cardiac transplantation. At six months post-transplantation, mean serum creatinine was 2.0 +/- 0.6 mg/dl (range 1.3 to 3.5 mg/dl). None of the transplanted patients required subsequent renal support. Seven patients died with a VAD before transplantation. Three died early (<1 month) after VAD placement, and all three required CVVHD until death. Four patients survived for >1 month after VAD placement; all four had resolution of renal dysfunction with mean serum creatinine of 1.9 +/- 1.2 mg/dl (range 0.8 to 3.6 mg/dl) without the need for renal support. Overall 30-day and six-month survival after VAD placement, survival to transplantation, and survival one year post-transplantation were similar to patients without severe renal dysfunction.

CONCLUSIONS

Contemporary use of VAD leads to resolution of severe renal dysfunction in most cardiogenic shock patients and comparable long-term outcomes to patients without renal dysfunction.

Prologue: ventricular assist devices and total artificial hearts. A historical perspective

In the 1960s, when LVADs and TAHs were introduced into clinical use, researchers estimated that, with this technology, the problem of heart failure could be solved within 20 years. Unfortunately, the evolution of these devices has taken much longer than anticipated. Nevertheless, significant advances have been achieved in both cardiac assistance and replacement, and today's cardiac surgeons have a wide range of devices from which to choose (Table 4). This progress has largely been due to the support of the NHLBI, especially the Devices and Technology Division headed by John Watson, and of the devoted commitment of the investigators. Because of the long-term commitment required for both basic and clinical research, commercial medical technology companies are unable to assume this burden. Advances in mechanical circulatory support and replacement have benefited numerous patients worldwide who would otherwise have died of heart failure, and devices now exist for use as bridges to recovery, bridges to transplant, and destination therapy. The current challenge is to refine what we have and to apply these technologies to broader patient populations with maximal safety and at a reasonable cost.

Determinants of outcome after heterotopic heart transplantation

BACKGROUND

Donor availability is currently the major factor limiting the use of heart transplantation as a treatment for severe heart failure. Heterotopic heart transplantation may address this issue by allowing the use of smaller donor organs, which otherwise may not be used.

METHODS

We analyzed the outcome of 42 consecutive, adult heterotopic transplantations performed between 1993 and 1999 at our center and compared them with the 303 consecutive orthotopic transplants performed in adult patients during the same period.

METHODS

Univariate analysis showed a relative risk for death of 1.8 at 1 year after transplantation for the heterotopic group compared with the orthotopic transplantation group (p = 0.04). Multiple regression analysis using a proportional hazards model showed that donor-recipient size-mismatch, i.e., donor body surface area < or =75% of recipient body surface area (p = 0.0001), donor age (p = 0.0001), and use of a female donor (p = 0.04) were significant risk factors but heterotopic transplantation per se was not. A Kaplan-Meier survival analysis of heterotopic vs orthotopic transplantation showed that 30-day survival was 76% vs 87%. By 1 year, this was 59% vs 74%. At 3 years, the comparison was 56% vs 69%. Repeating this analysis after sub-dividing the heterotopic group into those size-matched vs size-mismatched, the 1-year survival was 81% vs 45%, respectively (p = 0.02).

CONCLUSIONS

Heterotopic transplantation using a size-matched graft resulted in similar survival to that seen after orthotopic transplantation during the same period. Heterotopic transplantation with an undersized graft resulted in significantly decreased survival.

Predictors of Quality of Life at 1 Month After Implantation of a Left Ventricular Assist Device

• Objectives To describe quality-of-life outcomes; determine relationships between quality of life and demographic, physical, psychosocial, and clinical variables; and identify predictors of quality of life at 1 month after implantation of a left ventricular assist device.

• Methods Patients who received either an implantable pneumatic (n = 38) or a vented electric (n = 54) left ventricular assist device as a bridge to heart transplantation between August 1, 1994, and August 31, 1999, completed 6 instruments used to measure quality of life and factors related to quality of life. Data were analyzed by using descriptive statistics, Pearson correlations, Mann-Whitney U tests, and forward, stepwise multiple regression.

• Results Overall satisfaction with quality of life was quite high as determined from the total score on the Quality of Life Index (mean = 0.69). Patients were very satisfied with the implantation and thought that they would do well after future heart transplant surgery. Patients had a moderate level of stress. Significant predictors of overall quality of life were psychological symptoms, stress, and race; these accounted for 46% of variance in quality of life.

• Conclusions Patients were satisfied with their quality of life at 1 month after implantation of a left ventricular assist device. However, they were least satisfied with their health and functioning and yet were optimistic about how well they thought they would do after heart transplantation. Psychological factors were the strongest predictors of satisfaction with overall quality of life.

Implantation of the permanent Jarvik-2000 left ventricular assist device: a single-center experience

OBJECTIVES

We sought to evaluate the surgical results and effects of continuous support with the permanent Jarvik-2000 left ventricular assist device (LVAD). We report the early outcomes.

BACKGROUND

A shortage of transplant donors necessitates the testing of alternative treatments. The Jarvik-2000 is an axial flow pump with a percutaneous retro-auricular power connector, designed for permanent use.

METHODS

Patients with severe heart failure (HF), unsuitable for heart transplantation or conventional LVAD support, were offered implantation. The surgical approach included a left lateral thoracotomy. The device was implanted into the left ventricular apex on femoro-femoral bypass. It is set to allow pulsatile flow with an aortic valve opening. Anticoagulation is adjusted the same as for patients with a heart valve.

RESULTS

Between May 2001 and August 2001, we implanted the Jarvik-2000 in two patients with dilated cardiomyopathy and in one with cardiac amyloidosis, all with severe HF (cardiac index 1.8 +/- 0.3 l/m(2) per min). One patient required preoperative inotropic support. All patients did well, with no repeat operations or infections. Patients received 4.3 +/- 3.2 packed red blood cells and were intubated at 14 +/- 3 h, and the intensive care unit stay was 7.0 +/- 0.5 days. The cardiac index increased from 3.7 +/- 1.5 l/min per m(2) at 8,000 rpm to 5.9 +/- 2.9 l/min per m(2) at 12,000 rpm. All patients currently have mild hemolysis not requiring transfusion. The following postoperative events were recorded: a transient ischemic attack with complete recovery, a short re-intubation due to ventricular arrhythmia, loss of consciousness with a battery change while standing, knee-joint effusion after ergometry training, a minor wound problem and a short hospital re-admission due to dehydration. Patients were discharged home after 49 +/- 7 days; one has returned to work. All quality-of-life scores have improved.

CONCLUSIONS

The permanent Jarvik-2000 appears safe. It can be used for dilative or restrictive disease. The Jarvik-2000 might prove a valid option for the long-term treatment of patients with severe HF.

Left ventricular assist device therapy improves utilization of donor hearts

OBJECTIVES

We sought to determine the survival experiences of patients bridged to heart transplantation with either intravenous (IV) inotropes or an implantable left ventricular assist device (LVAD).

BACKGROUND

Because of the operative risks of LVAD implantation and the reported lower mortality associated with inotropic therapy, bridging to heart transplantation with inotropes is thought to be the preferred treatment option.

METHODS

Between April 1, 1996, and May 10, 2001, a total of 104 patients were bridged to heart transplantation with either IV inotropes (n = 38) or an implantable LVAD (n = 66; HeartMate). Survival was compared (Kaplan-Meier method) for three periods: survival to transplantation, post-transplantation survival and overall survival (i.e., survival from the onset of bridging to follow-up).

RESULTS

Survival to transplantation was 81 +/- 5% at three months for the LVAD group and 64 +/- 11% for the inotrope group (p = NS). Post-transplantation survival was 95 +/- 4% at three years for the LVAD group (two deaths) and 65 +/- 10% at three years for the inotrope group (nine deaths; p = 0.007). Overall survival was 77 +/- 6% at three years for the LVAD group and 44 +/- 9% at three years for the inotrope group (p = 0.01).

CONCLUSIONS

Overall survival for patients who were bridged to heart transplantation with an implantable LVAD was superior to that of patients who were bridged with inotropes. Bridging to transplantation with an implantable LVAD improves utilization of donor hearts.

Decreased plasma concentration of brain natriuretic peptide as a potential indicator of cardiac recovery in patients supported by mechanical circulatory assist systems

OBJECTIVES

We sought to investigate the relationship between the plasma concentration of brain natriuretic peptide (BNP), echocardiographic findings and the clinical outcome of patients supported with ventricular assist devices (VADs) to determine the role of BNP as a predictor for cardiac recovery.

BACKGROUND

Ventricular unloading in patients with end-stage heart failure supported by VADs may lead to myocardial recovery. The BNP is produced in the myocardium in response to chronic volume overload, but the effects on it of ventricular unloading by VADs are largely unknown.

METHODS

Twenty-one patients diagnosed with nonischemic cardiomyopathy and supported by VADs were evaluated for echocardiographic data and blood chemistry including BNP. They were divided into patients who died while on mechanical support (group I; n = 9), patients who were transplanted (group II; n = 8) and patients who were successfully weaned off the system and did not require transplantation (group III; n = 4).

RESULTS

Brain natriuretic peptide plasma concentrations decreased significantly after initiation of mechanical circulatory support (p = 0.017). Furthermore, the changes in BNP plasma concentrations showed a faster decrease to normal levels within the first week after implantation of the VAD in patients who were weaned off the system (group III) compared to patients in group I and group II.

CONCLUSIONS

This study shows that ventricular unloading with VADs decreases BNP plasma concentrations in patients who suffer from end-stage heart failure. Furthermore, we hypothesize that an early decrease of BNP plasma concentration may be indicative of recovery of ventricular function during mechanical circulatory support.

Multicenter clinical evaluation of the HeartMate vented electric left ventricular assist system in patients awaiting heart transplantation

BACKGROUND

Despite advances in heart transplantation and mechanical circulatory support, mortality among transplant candidates remains high. Better ways are needed to ensure the survival of transplant candidates both inside and outside the hospital.

METHODS

In a prospective, multicenter clinical trial conducted at 24 centers in the United States, 280 transplant candidates (232 men, 48 women; median age, 55 years; range, 11-72 years) unresponsive to inotropic drugs, intra-aortic balloon counterpulsation, or both, were treated with the HeartMate Vented Electric Left Ventricular Assist System (VE LVAS). A cohort of 48 patients (40 men, 8 women; median age, 50 years; range, 21-67 years) not supported with an LVAS served as a historical control group. Outcomes were measured in terms of laboratory data (hemodynamic, hematologic, and biochemical), adverse events, New York Heart Association functional class, and survival.

RESULTS

The VE LVAS-treated and non-VE LVAS-treated (control) groups were similar in terms of age, sex, and distribution of patients by diagnosis (ischemic cardiomyopathy, idiopathic cardiomyopathy, and subacute myocardial infarction). VE LVAS support lasted an average of 112 days (range, < 1-691 days), with 54 patients supported for > 180 days. Mean VE LVAS flow (expressed as pump index) throughout support was 2.8 L x min(-1) x m(-2). Median total bilirubin values decreased from 1.2 mg/dL at baseline to 0.7 mg/dL (P =.0001); median creatinine values decreased from 1.5 mg/dL at baseline to 1.1 mg/dL (P =.0001). VE LVAS-related adverse events included bleeding in 31 patients (11%), infection in 113 (40%), neurologic dysfunction in 14 (5%), and thromboembolic events in 17 (6%). A total of 160 (58%) patients were enrolled in a hospital release program. Twenty-nine percent of the VE LVAS-treated patients (82/280) died before receiving a transplant, compared with 67% of controls (32/48) (P <.001). Conversely, 71% of the VE LVAS-treated patients (198/280) survived: 67% (188/280) ultimately received a heart transplant, and 4% (10/280) had the device removed electively. One-year post-transplant survival of VE LVAS-treated patients was significantly better than that of controls (84% [158/188] vs 63% [10/16]; log rank analysis P =.0197).

CONCLUSION

The HeartMate VE LVAS provides adequate hemodynamic support, has an acceptably low incidence of adverse effects, and improves survival in heart transplant candidates both inside and outside the hospital. The studies of the HeartMate LVAS (both pneumatic and electric) for Food and Drug Administration approval are the only studies with a valid control group to show a survival benefit for cardiac transplantation.

Quality of life outcomes after heart transplantation in individuals bridged to transplant with ventricular assist devices

BACKGROUND

Increasing numbers of individuals receive ventricular assist devices (VADs) as bridges to heart transplantation. Physical morbidity risks and benefits, and quality of life (QOL) during VAD support have been documented. Effects of pre-transplant VAD support on functional and QOL outcomes after transplantation have received no empirical attention.

METHODS

Sixty-three VAD patients who received heart transplants underwent QOL evaluations of physical functioning, emotional and cognitive well-being, and social functioning at 2, 7, and 12 months after transplant (response rate = 95%). Ninety patients who had not received VADs--matched to the VAD group on cardiac-related and sociodemographic characteristics--served as longitudinal controls.

RESULTS

Both VAD and non-VAD groups showed similar levels and similar, statistically significant (p < 0.05) improvement in physical functioning (sleep, body care, mobility, ambulation, overall functional status, number of somatic complaints) across the study period. Emotional well-being (elevated depressive, anxiety, and anger symptoms; post-traumatic stress disorder rate) was stable or improved in both groups, and VAD patients showed significantly lower anxiety rates. The VAD patients' post-transplant cognitive status was significantly poorer. The VAD patients were significantly less likely to return to employment; other social functioning measurers (daily concerns, interpersonal activities/involvement, role function) showed mixed effects. Cognitive impairment explained much of the association between VAD support and post-transplant employment.

CONCLUSIONS

Although post-transplant physical and emotional recovery is similar in VAD and non-VAD patients, VAD patients retain more cognitive impairment and show mixed changes in social functioning. Increased attention to strategies to maximize VAD patients' cognitive capacity is required to facilitate social reintegration.

Hypotension, acidosis, and vasodilatation syndrome post-heart transplant: prognostic variables and outcomes

BACKGROUND

In recent years a syndrome characterized by hypotension, acidosis, and vasodilatation, which we have designated HAV syndrome, has been reported to occur more frequently after heart transplantation (HT), but its pathogenesis is unknown.

METHODS

We analyzed consecutive patients undergoing HT between January 1994 and June 1998 (aged 50 +/- 8 years; 87% male; 40% African American; ischemia time, 190 +/- 20 minutes; given triple immunosuppression without anti-lymphocyte antibodies) in 2 groups: 38 (54%) who developed HAV (systemic vascular resistance < or = 800 dines x sec x cm(-5) and serum bicarbonate < or = 20 mEq/liter) and 32 (46%) who did not. To identify causes of HAV, we compared 113 pre-HT donor and recipient variables, 28 peri-HT variables, and 46 post-HT variables between groups. We used Mann-Whitney, Fisher exact, and chi-squared tests to compare variables and to determine significance.

RESULTS

Univariate analysis showed that HAV patients had significantly greater recipient and donor weight (p = 0.000007 and 0.0017, respectively), longer ischemia times (p = 0.0052), pre-HT use of beta-blockers (p = 0.009), and longer waiting times for HT (p = 0.018). African-American patients had less HAV than Caucasians (p = 0.047). Patients with pre-HT mechanical circulatory assistance had less HAV than pharmacologically treated patients (p = 0.014). Multivariate analysis showed that recipient (p = 0.0004) and donor weight (p = 0.0394) and ischemia time (p = 0.0015) independently predicted HAV and correlated with HAV severity. Deaths at < or =30 days of HT occurred more in patients with (33%) than in those without (15%) HAV.

CONCLUSIONS

(1) Hypotension, acidosis, and vasodilatation after HT are associated with high mortality. (2) Recipient and donor weights and ischemia time are independent risk factors for HAV. (3) Pre-HT mechanical circulatory assistance and African-American race confer protection against HAV. (4) Because HAV risk factors can be altered, prevention may be possible. Further study is needed to identify the cellular and humoral mediators of HAV.

Comparison of right and left ventricular responses to left ventricular assist device support in patients with severe heart failure: a primary role of mechanical unloading underlying reverse remodeling

BACKGROUND

Left ventricular assist devices (LVAD) reverse ventricular, myocardial, and systemic abnormalities characteristic of severe heart failure (reverse remodeling). The relative contributions of hemodynamic unloading and normalized biochemical milieu to reverse remodeling are unknown.

METHODS AND RESULTS

Structural and functional characteristics were measured from 53 hearts of patients undergoing transplantation without LVAD support (medical support) and 33 hearts from patients receiving a median of 46 days of LVAD support (range, 8 to 360 days). Compared with medical support alone, patients receiving LVAD support for >/=30 days had higher central venous pressures (11+/-6 versus 8+/-5 mm Hg, P=0.04), lower pulmonary artery diastolic pressures (14+/-9 versus 21+/-9 mm Hg, P=0.01), and higher cardiac outputs (5.1+/-1.6 versus 3.7+/-1.0 L/min, P<0.001). In LVAD versus transplantation hearts, V(30) (ex vivo volume yielding ventricular pressure of 30 mm Hg) was decreased in the left ventricle (LV) (179+/-75 versus 261+/-118 mL, P=0.005) but not in the right ventricle (RV) (140+/-59 versus 148+/-52 mL, P=NS). LV myocyte diameter decreased more significantly after LVAD support (17%, P=0.05) than in the RV (11%, P=NS). Compared with transplantation, LVAD support increased normalized SERCA2a content in the LV (0.51+/-0.26 versus 1.04+/-0.34, P<0.001) but not in the RV (0.48+/-34 versus 0.67+/-0.55, P=NS). Finally, LVAD support improved force-frequency relations of isolated superfused LV trabeculae (P=0.01) but not RV trabeculae.

CONCLUSIONS

Reduction of hemodynamic load is a primary factor underlying several important features of reverse remodeling. These findings do not preclude a possible primary role of neurohormonal factors underlying other facets of reverse remodeling during LVAD support.

Preliminary result of an algorithm to select proper ventricular assist devices for high-risk patients with extracorporeal membrane oxygenation support

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) is not suitable for long-term support because of its high incidence of complications. Conversion from ECMO to ventricular assist device (VAD) is reasonable, and we have developed a simple algorithm for selecting proper VADs for these ECMO-supported patients.

METHODS

We converted 12 patients who were receiving ECMO support to VAD for bridge to transplantation. Group I (n = 6) was converted directly from ECMO to VAD. Group II (n = 6) underwent stage conversion. We added left atrial drainage to ECMO because of lung edema or marked left heart distension. We discontinued drainage after recovery of right heart function. Group II had more unfavorable risk factors for VAD before ECMO.

RESULTS

Three patients (50%) in Group I received biventricular VADs. The other 3 patients were converted to left ventricular assist device (LVAD), but only 1 (16.7%) experienced successful conversion. We successfully converted 5 patients (83.3%) in Group II to LVAD without right VAD, and 4 of them could be weaned from the ventilator. The multiple-organ dysfunction score gradually improved in Group II despite additional surgery. Two patients in each group received heart transplantation and survived long term.

CONCLUSION

Using a conversion protocol provides a good guideline for making decisions. According to the protocol, right heart and pulmonary function can be clearly assured before shifting to LVAD in these critical ECMO-supported patients.

Application of "double bridge mechanical" resuscitation for profound cardiogenic shock leading to cardiac transplantation

BACKGROUND

In patients with acute profound cardiogenic circulatory failure unresponsive to conventional resuscitation, we instituted immediate aggressive application of extracorporeal membrane oxygenation (ECMO) to restore circulatory stability. Long-term hemodynamic support was accomplished with an early "bridge" to ventricular assist device (VAD) before definitive treatment with cardiac transplantation.

METHODS

A respective review of ECMO and VAD data registries was instituted.

RESULTS

From May 1996 to July 2000, 23 patients were placed on ECMO support for profound cardiogenic circulatory failure. Eleven patients (47%) were withdrawn from support due to severe neurologic injury or multisystem organ failure. Three patients (13%) were weaned off ECMO with good outcome. Nine patients (39%) were transferred to a VAD. Two patients expired while on VAD support, and 7 of the VAD-supported patients (78%) survived to transplantation. Overall survival was 43%.

CONCLUSIONS

Emergent ECMO support is a salvage approach for cardiac resuscitation once conventional measures have failed. In neurologically intact patients, the early transfer to a VAD quickly stabilizes hemodynamics, avoids complications, and is essential for long-term circulatory support before definitive treatment with cardiac transplantation.

Risk analysis in patients bridged to transplantation

BACKGROUND

Efforts to predict mortality in bridge to cardiac transplant patients have concentrated on preventricular assist device (VAD) status. To more fully identify factors influencing survival to transplant, we reviewed the preoperative and postoperative VAD courses of 105 bridge to transplant patients.

METHODS

Sixty-four parameters (34 pre-VAD, 30 post-VAD), including hemodynamics, complications, and evaluations of major organ function were examined and analyzed.

RESULTS

Thirty-three patients (31%) died on VADs and 72 were transplanted. There were two posttransplant operative deaths (3%). By univariate analysis 23 of 64 factors were significant. These 23 factors were entered into a stepwise logistic regression analysis to identify predictors of survival to transplant. Four factors, including pre-VAD intubation (p < 0.005), cardiopulmonary bypass (CPB) time during VAD insertion (p < 0.0001), mean pulmonary artery pressure (first postoperative day after VAD) (p < 0.0002), and highest post-VAD creatinine (p < 0.01) were independent predictors of transplantation.

CONCLUSIONS

Other than the need for intubation, pre-VAD variables were of little value in predicting survival to transplant. Problems during VAD insertion (long CPB time) and post-VAD renal insufficiency were independent predictors. Severe complications that developed during the interval of VAD support, including cerebrovascular accident, bleeding and infection, were surprisingly not predictors for transplantation.

Improvement in quality of life outcomes 2 weeks after left ventricular assist device implantation

BACKGROUND

The successful use of left ventricular assist devices (LVADs) as a bridge to heart transplantation has prompted our examination of quality of life (QOL) outcomes. The purposes of this study are to describe QOL in patients 1 to 2 weeks after LVAD implantation and to compare QOL in a smaller cohort of patients from before to 1 to 2 weeks after surgery.

METHODS

Data were collected from a convenience sample of 81 patients who completed booklets of questionnaires that measure domains of QOL 1 to 2 weeks after LVAD insertion and from 30 of 81 patients who completed booklets at both the pre-implantation and post-implantation periods. Patients completed booklets of 6 to 8 self-reporting instruments, with acceptable reliability and validity. Data were analyzed using descriptive and comparative statistics (chi-square, Mann-Whitney U and Wilcoxon signed ranks tests) with p = 0.01 considered statistically significant.

RESULTS

One to 2 weeks after LVAD implantation, patients were quite satisfied with their lives, experienced moderately low amounts of stress, coped well, and perceived themselves as having good health and QOL, low symptom distress, and moderately low functional disability. Patients reported significantly better QOL, more satisfaction with health and functioning, and were significantly less distressed by symptoms from immediately pre-operatively to post-operatively. However, patients reported significantly more self-care disability and more dissatisfaction with socioeconomic areas of life from before to immediately after surgery. Psychological distress was low and did not change with time.

CONCLUSION

Given that QOL improved from before to after LVAD implantation, our findings provide a springboard for investigation of the impact of LVADs on long-term QOL outcomes.

Making choices in cardiology: difficulties of rationing and equality of access

Ethics, clinical performance, resource constraints and research all interact regularly in informing and driving the debate about the direction of health care in modern societies. Medicine has become the practice of what should be done rather than the art merely of what is possible. A public report criticising one of Europe's leading heart centres of being less willing to perform complex heart surgery in children with Down's syndrome generated a thoughtful discussion on whether equality of access is compatible with resource decisions in the rationing of limited health care resources. This and the developments in new high-technology solutions to end-stage heart failure make decision making on the cardiovascular medicine of the 21(st) century ever more important. This article discusses these issues in the light of realisation that performance issues, greater public oversight of medical decision making and the expansion of expensive medical options set policy makers, the public and the medical profession on a collision course which only prolonged and thoughtful debate can avoid.

The use of extracorporeal life support in adult patients with primary cardiac failure as a bridge to implantable left ventricular assist device

BACKGROUND

Extracorporeal life support (ECLS) is an effective technique for providing emergent circulatory assistance, and may represent a life-saving option in patients who might not initially be considered a candidate for other forms of circulatory support (extracorporeal or implantable left ventricular assist device [LVAD]). In the setting of cardiac arrest, ECLS represents the only viable method of initiating circulatory support. However, ECLS has a number of disadvantages that include high complication rates (eg, stroke, bleeding) and a limited duration of potential support, which have prevented its widespread acceptance, particularly in the adult population. With the increased successful application of long-term implantable LVADs as a bridge to transplant, the major limitation of ECLS could be overcome by bridging patients to a long-term implantable LVAD ("bridge to bridge"), thereby reducing the reluctance to utilize ECLS when indicated. After acquisition of the HeartMate LVAD (Thermo Cardiosystems, Inc, Woburn, MA) we investigated the use of ECLS as a bridge to an implantable LVAD and subsequent transplantation in selected high-risk patients.

METHODS AND RESULTS

From Oct 1, 1996 to Sept 30, 2000, 33 adult patients presenting with cardiac arrest or severe hemodynamic instability were placed on ECLS for the bridge to bridge indication. Of the 33 patients, 10 patients survived to LVAD implant, 1 was bridged directly to transplant, 5 weaned from ECLS, and 16 died on ECLS. Overall, 12 patients survived to discharge. One-year actuarial survival from the initiation of ECLS was 36%. One-year actuarial survival from the time of LVAD implant, conditional on surviving ECLS, was 80%.

CONCLUSIONS

The 1-year survival of adult patients placed on ECLS and who subsequently survived to an implantable LVAD was favorable. These data support a strategy of ECLS to implantable LVAD bridge to heart transplant in adult patients who are in need of circulatory support and who are not initially candidates for other forms of mechanical support. The favorable results of this strategy support utilization of ECLS even in situations where myocardial recovery is thought to be unlikely.

A versatile intracorporeal ventricular assist device based on the thoratec VAD system

BACKGROUND

As patients are supported for longer durations with paracorporeal Thoratec left ventricular and biventricular assist devices (longest durations: 515 and 457 days, respectively), there is a need for implantable options.

METHODS

We are developing a small, simple, and versatile intracorporeal ventricular assist device (IVAD) for left, right, or biventricular support as an alternative to the large, implantable, pulsatile left ventricular assist device (LVAD) systems available today. The new device is based on the Thoratec paracorporeal VAD that has been used in more than 1,400 patients weighing from 17 to 144 kg and for durations exceeding 1 year including patient discharge (using the portable driver).

RESULTS

The IVAD has the same blood flow path and Thoralon polyurethane blood pumping sac as the paracorporeal VAD, but the housing is a smooth contoured, polished titanium alloy. The IVAD has a new sensor to detect when the pump is full and empty, and is controlled with the Thoratec TLC-II portable VAD driver, which is a small, briefcase-sized, battery-powered, pneumatic control unit. A small flexible (9 mm OD) percutaneous pneumatic driveline for each VAD is tunneled out of the body from the LVAD or right VAD in a pre- or intraperitoneal position. Small size and simplicity are the major advantages of the new device. The IVAD weight (339 g) and implanted volume (252 mL) are approximately one-half that of the current implantable pulsatile electromechanical LVAD systems.

CONCLUSIONS

The small size of the IVAD should not only allow support of a large range of patient sizes and body habitus, but also provide options for implantable left, right, or biventricular support. By implanting only the mechanically simple blood pump, the more complex control unit is external, where it can be serviced and replaced without surgery. The IVAD with the portable driver will be a viable alternative to large implanted electromechanical systems and should address a larger segment of the physically diverse patient population.

Lessons learned from the first clinical implants of the DeBakey ventricular assist device axial pump: a single center report

BACKGROUND

The bridge to transplantation with pulsatile mechanical assist devices became a standard procedure for patients deteriorating on the waiting list. Recently, continuous flow axial impeller pumps were introduced to clinical application offering new advantages.

METHODS

From November 1998 till September 2000, 6 male patients (mean age 53 plus or minus 11 years) with end-stage left heart failure were implanted with a DeBakey ventricular assist device (VAD) axial-flow pump for bridge to transplantation.

RESULTS

Three patients were successfully transplanted after 74, 115, and 117 days, respectively. Two other patients died after 25 and 133 days. One patient is still on the device after 108 days. Because of modification of the implantation technique after the first 2 patients, mean pump-flow within the first 3 weeks was increased from 4.3 +/- 0.6 L/min to 6.7 +/- 0.3 L/min. Patients were put on regular bicycle-ergometer training and improved their exercise capacities up to a mean maximum oxygen consumption of 20.2 mL/kg/min.

CONCLUSIONS

Initial implants of the DeBakey VAD demonstrated support properties comparable to pulsatile pumps but without significant restrictions for extended use.

Research and development of an implantable, axial-flow left ventricular assist device: the Jarvik 2000 Heart

Advances in technology and increased clinical need have led to the development of a new type of blood pump. The Jarvik 2000 Heart is an electrically powered, axial-flow left ventricular assist device that has been developed during the past 13 years. Unlike first-generation left ventricular assist devices, which were developed in the 1970s and were designed to totally capture the cardiac output, the Jarvik 2000 is designed to normalize the cardiac output by augmenting the function of the chronically failed heart for extended periods. Design iterations have been tested in 67 animals, and clinical trials have recently begun. Three patients have received the Jarvik 2000 as a bridge to transplantation, and 1 patient is being supported permanently outside the hospital. All 4 patients have improved from New York Heart Association functional class IV to class I, and 2 of them have been discharged from the hospital after heart transplantation. The experimental and clinical results indicate that the Jarvik 2000 can provide physiologic support with minimal complications and is reliable, biocompatible, and easy to implant.

Management of perioperative ventricular dysfunction

With the recognition of the clinical importance of the right ventricle; the development of new techniques for the perioperative evaluation of RV function, particularly transesophageal echocardiography; and new treatment modalities (pharmacologic and mechanical), clinicians will be able to more accurately diagnose and precisely manage patients who have sustained RV injury.

Assessment of an extracorporeal life support to LVAD bridge to heart transplant strategy

BACKGROUND

Extracorporeal life support (ECLS) is an effective technique for providing emergent circulatory assistance. However, its use in adult patients is associated with poor survival when myocardial function fails to recover. Due to the prolonged waiting times for heart transplantation, ECLS as a bridge to transplant is associated with poor survival. In addition, ECLS has been reported to be a significant risk factor for death after bridging to an implantable left ventricular assist device (LVAD). After acquisition of the HeartMate LVAD (Thermo Cardiosystems, Inc) in October 1996, we began using ECLS as a bridge to an implantable LVAD and subsequently transplantation in selected high-risk patients.

METHODS

From October 1, 1996 to December 1, 1999, 60 adult patients presenting with cardiogenic shock were evaluated for circulatory assistance.

RESULTS

Twenty-five patients (group 1) with cardiac arrest or severe hemodynamic instability and multiorgan failure were placed on ECLS. Eight patients survived to LVAD implant, 1 was bridged directly to transplant, and 4 weaned from ECLS. Nine patients in group 1 survived to discharge. Thirty patients (group 2) underwent LVAD implant without ECLS. Twenty-three were bridged to transplant, with 22 surviving to discharge. Five patients (group 3) were placed on extracorporeal ventricular assist with 3 bridged to transplant and all surviving to discharge. One-year actuarial survival from the initiation of circulatory support was 36% (group 1), 73% (group 2), and 60% (group 3). One-year actuarial survival from the time of LVAD implant in group 1, conditional on surviving ECLS, was 75% (p = NS compared with group 2).

CONCLUSIONS

In selected high-risk patients, LVAD survival after initial ECLS was not different from survival after LVAD support alone. An initial period of resuscitation with ECLS is an effective strategy to salvage patients with cardiac arrest or extreme hemodynamic instability and multiorgan injury.

Infectious complications associated with ventricular assist systems

Infectious complications during support with a ventricular assist system (VAS) can cause severe morbidity and mortality, affecting nearly one-half of all VAS recipients. Because of the lack of a uniform definition of infection, the incidence of this complication is hard to determine accurately. It is approximately 50% for patients being supported by an implantable VAS as a bridge to heart transplantation and 28% for patients supported by an external, short-term VAS. Infections can be classified according to the involvement or noninvolvement of the implanted device and according to the severity of the infection. Severe infections involving the implanted device may preclude heart transplantation for some patients, but numerous patients with milder infections have undergone successful transplantation. Numerous factors predispose VAS patients to infection. Postoperative bleeding necessitating re-operation is an important contributing factor. Endotracheal tubes, intravascular catheters, and other indwelling tubes necessary for the care of postsurgical patients are also common routes of contamination. Control of infection may be improved with new VAS designs, antibiotic impregnated drivelines, and innovative therapies such as antibiotic beads. The next generation of VASs should be inherently less susceptible to infection because of their smaller size, reduced thrombogenicity, and better flow characteristics. In addition to more effective antibiotics, improved VAS designs that incorporate transcutaneous energy transmission systems may reduce infectious complications and allow safe, long-term VAS support.

Relationship of blood pressure and pump flow in an implantable centrifugal blood pump during hypertension

The purpose of this study was to evaluate the real time relationship between pump flow and pump differential pressure (D-P) during experimentally induced hypertension (HT). Two calves (80 and 68 kg) were implanted with the EVA-HEART centrifugal blood pump (SunMedical Technology Research Corp., Nagano, Japan) under general anesthesia. Blood pressure (BP) in diastole was increased to 100 mm Hg by norepinephrine to simulate HT. Pump flow, D-P, ECG, and BP were measured at pump speeds of 1,800, 2,100, and 2,300 rpm. All data were separated into systole and diastole, and pump flow during HT was compared with normotensive (NT) conditions at respective pump speeds. Diastolic BP was increased to 99.3+/-4.1 mm Hg from 66.5+/-4.4 mm Hg (p<0.01). D-P in systole was under 40 mm Hg (range of change was 10 to 40 mm Hg) even during HT. During NT, the average systolic pump flow volume was 60% of the total pump flow. However, during HT, the average systolic pump flow was 100% of total pump flow volume, although the pump flow volume in systole during HT decreased (33.1+/-5.7 vs. 25.9+/-4.0 ml/systole, p<0.01). In diastole, the average flow volume through the pump was 19.6+/-6.9 ml/diastole during NT and -2.2+/-11.1 ml/diastole during HT (p<0.01). The change in pump flow volume due to HT, in diastole, was greater than the change in pump flow in systole at each pump speed (p<0.001). This study suggests that the decrease of mean pump flow during HT is mainly due to the decrease of the diastolic pump flow and, to a much lesser degree, systolic pump flow.

Impact of current management practices on early and late death in more than 500 consecutive cardiac transplant recipients

OBJECTIVE

To study risk factors for early and late death after heart transplantation in the current era.

SUMMARY BACKGROUND DATA

The current cardiac transplant population differs from earlier periods in that an increasing number of sicker patients, such as those with ventricular assist device (LVAD) support, prior cardiac allotransplantation, and pulmonary hypertension, are undergoing transplantation. In addition, sensitized patients constitute a greater proportion of the transplanted population. Emphasis has been placed on therapies to prevent early graft loss, such as the use of nitric oxide and improved immunosuppression, in addition to newer therapies.

METHODS

Five hundred thirty-six patients undergoing heart transplantation between 1993 and 1999 at a single center were evaluated (464 adults and 72 children; 109 had received prior LVAD support and 24 underwent retransplantation). The mean patient age at transplantation was 44.9 years. Logistic regression and Cox proportional hazard models were used to evaluate the following risk factors on survival: donor and recipient demographics, ischemic time, LVAD, retransplantation, pretransplant pulmonary vascular resistance, and immunologic variables (ABO, HLA matching, and pretransplant anti-HLA antibodies).

RESULTS

The rate of early death (less than 30 days) was 8.5% in adults and 8.8% in children. The actuarial survival rate of the 536 patients was 83%, 77%, and 71% at 1, 3, and 5 years, respectively, by Kaplan Meier analysis. Risk factors adversely affecting survival included the year of transplant, donor age, and donor-recipient gender mismatching. Neither early nor late death was influenced by elevated pulmonary vascular resistance, sensitization, prior LVAD support, or prior cardiac allotransplantation.

CONCLUSIONS

Previously identified risk factors did not adversely affect short- or long-term survival of heart transplant recipients in the current era. The steady improvement in survival during this period argues that advances in transplantation have offset the increasing acuity of transplant recipients.

Clinical utility of echocardiography in the management of implantable ventricular assist devices

BACKGROUND

The high mortality rate of congestive cardiac failure, the cost and complications of cardiac transplantation, and the waiting list mortality rate resulting from donor organ scarcity have encouraged the development of surgical techniques as bridges to transplantation or as long-term palliative therapy. Implantable left ventricular assist devices are now routinely used as such a bridge, and within the REMATCH Trial, as permanent palliative devices in nontransplant candidates. These are mechanical managements with myriad mechanical complications and pitfalls. Echocardiography has been extensively used in our institution to detect and diagnose previously documented and hitherto unencountered complications of these procedures.

METHODS AND RESULTS

The role of echocardiography in these procedures, including preoperative patient selection, intraoperative transesophageal echocardiography, and postoperative troubleshooting and late follow-up, is discussed. We describe our clinical echocardiographic approach, which has developed over 91 assist-device procedures. The relative frequency and clinical impact of specific anatomic, physiologic, hemodynamic, and mechanical features are described. New techniques such as the Doppler quantification of assist device inflow obstruction are illustrated, as are the device cannula position, the detection of device valve failure, and the parameters related to the remodeling procedure.

CONCLUSIONS

Echocardiography in heart failure surgery has proved to be an invaluable tool in the diagnosis and management of mechanical complications. The experience gained in our institution may serve as an aid to new surgical programs treating these critically ill patients.

Left ventricular assist device implantation: short and long-term surgical complications

Long-term implanted left ventricular assist devices (LVADs) have significantly improved the care of patients awaiting heart transplantation and will provide an alternative therapy to select patients with heart failure. However, although the technology and clinical results continue to improve, LVAD implantation is still associated with a significant level of complications. Left ventricular assist device-associated complications can be broadly divided by their temporal occurrence. Early complications include perioperative hemorrhage, air embolism, and right ventricular failure. Beyond the perioperative period, late complications consist primarily of infection, thromboembolism, and primary device failure. An improved understanding of the mechanisms involved should aid the clinician in further reducing the incidence of these occurrences.

Left ventricular assist device-induced reverse ventricular remodeling

Left ventricular assist devices provide chronic pressure and volume unloading of the dilated left ventricle in patients with end-stage heart failure. This is associated with reverse structural remodeling (normalization of the passive pressure-volume relationship), reverse molecular remodeling (increased expression of several genes involved in calcium metabolism that are down-regulated in heart failure), improved baseline contractility, and improved contractile response to increased heart rate and to beta-agonist stimulation. These findings indicate the profound degree of recovery of myocardial properties in hearts previously considered to have invincible end-stage heart failure.

Clinical experience with long-term use of implantable left ventricular assist devices: indications, implantation, and outcomes

We describe our clinical experience with 205 implantable left ventricular assist devices at the Cleveland Clinic between December 1991 and January 2000, along with manufacturers' data submitted to the Food and Drug Administration. In patients with end-stage cardiac failure who are suitable candidates for transplantation, these devices serve as excellent bridges to transplantation. Recent modifications have increased pump reliability and reduced thromboembolic rates. The vented electric HeartMate (Thermocardiosystems Inc, Woburn, MA) and the Novacor (Baxter-Novacor, Oakland, CA) left ventricular assist systems allow patients to be discharged from the hospital while awaiting a donor heart. Experience with long-term support is providing insights into permanent implantation of these devices as destination therapy. Although infection remains a major impediment to long-term support, patient-pump interactions leading to changes in the coagulation and immune systems are being recognized, and these interactions may have important implications with respect to thromboembolism, infection, and sensitization to human leukocyte antigens (HLAs). Better understanding of these factors may eventually lead to the development of permanently implantable pumps as an alternative to transplantation.

Clinically available intracorporeal left ventricular assist devices

There are now 3 commercially approved intracorporeal left ventricular assist devices (LVADs). Product similarities include (1) LV apex, to pump, to ascending aorta flow patterns, (2) excellent hemodynamic support with reversal of heart failure and neurohormone/cytokine milieu, and (3) the requirement of major surgery for device implantation and later explantation, with or without transplant. Two electrically powered models allow a tether-free existence and hospital discharge. All complications are being addressed, and in the past decade, device failure and thromboemboli have been reduced. Infection continues to be an obstacle to more widespread adoption of therapy. Despite pre-LVAD shock, most patients (65% to 78% by Food and Drug Administration data) survive until transplant (averaging 80 to 96 days of LVAD support), and posttransplant survival is equal to nonbridged patients. As the problem of infection is reduced, more widespread LVAD use can be anticipated.

Changes in platelet activation associated with left ventricular assist system placement

BACKGROUND

Thromboembolic and hemorrhagic complications are common in patients after left ventricular assist system (LVAS) placement. Platelet physiology may be involved in these complications.

METHODS

Using flow cytometry, expression of CD62P and CD63 were analyzed as markers of platelet activation. Binding of annexin V was analyzed to determine platelet membrane asymmetry. Results from two patients who received a Novacor LVAS as a bridge to transplantation are reported.

RESULTS

Patients' platelets showed increased CD62P and CD63 expression, yet annexin V binding was not increased. They also revealed suppression of thrombin activation following LVAS placement, which approached normal after transplantation. Heparin suppressed thrombin activation, whereas aspirin or dipyridamole did not. Suppression was attenuated by protamine sulfate and heparinase.

CONCLUSIONS

Following LVAS placement, resting platelets demonstrate increased expression of activation markers.

Simple method of hemostasis in implantation and explantation of HeartMate left ventricular assist device

We described a simple method of hemostasis in implantation and explantation of HeartMate left ventricular assist device. Wrapping of the inflow cannula, outflow conduit and outflow graft with Vascutek tube graft can localize the bleeding due to patient's coagulopathy, imperfect coating and device defect. During explantation, bivalving the tube graft, leaving the graft in place and no-touch of the adhesion between graft and soft tissue can minimize the dissection and prevent the potential bleeding.

Preoperative risk factors for right ventricular failure after implantable left ventricular assist device insertion

BACKGROUND

Implantable left ventricular assist device (LVAD) insertion complicated by early right ventricular (RV) failure has a poor prognosis and is generally unpredictable.

METHODS

To determine preoperative risk factors for perioperative RV failure after LVAD insertion, patient characteristics and preoperative hemodynamics were analyzed in 100 patients with the HeartMate LVAD (Thermo Cardiosystems, Inc, Woburn, MA) at the Cleveland Clinic.

RESULTS

RV assist device support was required for 11 patients (RVAD group). RVAD use was significantly higher in younger patients, female patients, smaller patients, and myocarditis patients. There was no significant difference in the cardiac index, RV ejection fraction, or right atrial pressure between the two groups preoperatively. The preoperative mean pulmonary arterial pressure (PAP) and RV stroke work index (RV SWI) were significantly lower in the RVAD group (p = 0.015 and p = 0.011, respectively). Survival to transplant was poor in the RVAD group (27%) and was 83% in the no-RVAD group.

CONCLUSIONS

The need for perioperative RVAD support was low, only 11%. Preoperative low PAP and low RV SWI were significant risk factors for RVAD use.

Extracorporeal Life Support to Left Ventricular Assist Device Bridge to Heart Transplant

Background —The use of extracorporeal life support (extracorporeal membrane oxygenation [ECMO]) as a direct bridge to heart transplant in adult patients is associated with poor survival. Similarly, the use of an implantable left ventricular assist device (LVAD) to salvage patients with cardiac arrest, severe hemodynamic instability, and multiorgan failure results in poor outcome. The use of LVAD implant in patients who present with cardiogenic shock who have not been evaluated for transplantation or who have sustained a recent myocardial infarction also raises concerns. ECMO may provide reasonable short-term support to patients with severe hemodynamic instability, permit recovery of multiorgan injury, and allow time to complete a transplant evaluation before long-term circulatory support with an implantable LVAD is instituted. After acquisition of the HeartMate LVAD (Thermo Cardiosystems, Inc), we began using ECMO as a bridge to an implantable LVAD and, subsequently, to transplantation in selected high-risk patients.

Methods and Results —From October 1, 1996, through September 30, 1998, 32 adult patients who presented with refractory cardiogenic shock (cardiac index <2.0 L · min −1 · m −2 , with systolic blood pressure <100 mm Hg and pulmonary capillary wedge pressure ≥24 mm Hg and dependent on ≥2 inotropes with or without intra-aortic balloon pump) were evaluated and accepted as candidates for mechanical assistance as a bridge to transplant. Of the 32 patients, 14 (group I) had a cardiac arrest or severe hemodynamic instability (systolic blood pressure ≤75 mm Hg) with evidence of multiorgan failure (defined as serum creatinine level >3 mg/dL or oliguria; international normalized ratio >1.5 or transaminases >5 times normal or total bilirubin >3 mg/dL; and needing mechanical ventilation). Group I patients were placed on ECMO support; 7 underwent subsequent LVAD implant and 1 was bridged directly to transplant. Six patients in group I survived to transplant hospitalization discharge. The remaining 18 patients (group II) underwent LVAD implant without ECMO support; 12 survived to transplant hospitalization discharge and 2 remained alive with ongoing LVAD support and awaited transplant. One-year actuarial survival from the initiation of circulatory support was 43% in group I and 75% in group II. One-year actuarial survival from the time of LVAD implant in group I, conditional on surviving ECMO, was 71% ( P =NS compared with group II).

Conclusions —In appropriately selected high-risk patients, the rate of LVAD survival after initial ECMO support was not significantly different from the survival rate after LVAD support alone. An initial period of resuscitation with ECMO is an effective strategy to salvage patients with extreme hemodynamic instability and multiorgan injury. Use of LVAD resources is improved by avoiding LVAD implant in a very-high-risk cohort of patients who do not survive ECMO.

Altered exercise pulmonary function after left ventricular assist device implantation

The use of LVADs as a bridge to heart transplantation is increasing steadily as more surgical centers add this effective strategy for end-stage heart failure patients. Fundamental exercise physiology in the presence of LVADs has been described previously, and data is available that supports the safety and efficacy of exercise in this population. Variants to the expected exercise response that may be secondary to LVAD implantation, such as the pulmonary restrictive pattern that developed in the patient described in this case study, may occur. Clinicians should consider assessment and monitoring of pulmonary function in this patient population, especially in patients with exercise-induced dyspnea and perhaps patients with pre-existing pulmonary limitation.

Aortic valve patch closure: an alternative to replacement with HeartMate LVAS insertion

A PTFE patch sewn to the aortic valve and annulus, to occlude the ventriculoaortic junction is used to successfully correct aortic insufficiency with HeartMate (LVAS) insertion. This represents an inexpensive alternative to aortic valve replacement for aortic insufficiency or the presence of a mechanical aortic valve.