P. Hoagland

Clinical strategies and outcomes in advanced heart failure patients older than 70 years of age receiving the HeartMate II left ventricular assist device: a community hospital experience.

OBJECTIVES The primary objective of this study was to determine outcomes in left ventricular assist device (LVAD) patients older than age 70 years. BACKGROUND Food and Drug Administration approval of the HeartMate II (Thoratec Corporation, Pleasanton, California) LVAD for destination therapy has provided an attractive option for older patients with advanced heart failure. METHODS Fifty-five patients received the HeartMate II LVAD between October 5, 2005, and January 1, 2010, as part of either the bridge to transplantation or destination therapy trials at a community hospital. Patients were divided into 2 age groups: ≥ 70 years of age (n = 30) and < 70 years of age (n = 25). Outcome measures including survival, length of hospital stay, adverse events, and quality of life were compared between the 2 groups. RESULTS Pre-operatively, all patients were in New York Heart Association functional class IV refractory to maximal medical therapy. Kaplan-Meier survival for patients ≥ 70 years of age (97% at 1 month, 75% at 1 year, and 70% at 2 years) was not statistically different from patients <7 0 years of age (96% 1 month, 72% at 1 year, and 65% at 2 years, p = 0.806). Average length of hospital stay for the ≥ 70-year age group was 24 ± 15 days, similar to that of the < 70-year age group (23 ± 14 days, p = 0.805). There were no differences in the incidence of adverse events between the 2 groups. Quality of life and functional status improved significantly in both groups. CONCLUSIONS The LVAD patients ≥ 70 years of age have good functional recovery, survival, and quality of life at 2 years. Advanced age should not be used as an independent contraindication when selecting a patient for LVAD therapy at experienced centers.

Aortic valve closure associated with HeartMate left ventricular device support: Technical considerations and long-term results

BACKGROUND Aortic valve integrity is crucial for optimal left ventricular assist device (LVAD) support. Pre-existing native aortic insufficiency, aortic valve incompetence acquired during support, as well as previously placed prosthetic aortic valves present unique problems for these patients. METHODS We reviewed and analyzed data for 28 patients who underwent left ventricular outflow tract closure associated with HeartMate I (n =12) and HeartMate II (n = 16) LVAD insertion or exchange. Indications for valve closure, surgical technique, LVAD function, survival rates and complications were retrospectively analyzed. Survival rates were compared with those of HeartMate LVAD patients (n = 104) who did not undergo aortic valve closure. RESULTS Indications for closure included native aortic valve insufficiency (10 patients), aortic valve deterioration after prolonged LVAD support (8 patients) and previously placed mechanical (9 patients) or bioprosthetic aortic prostheses (1 patient). There were 2 operative and 5 late deaths (mean 227 days post-operatively). Of the deaths, none were due to aortic valve closure. Actuarial survival was 78% at 1 year and 53% at 3 years, which was statistically better than for our patients with an intact aortic outflow (61% at 1 year, 45% at 3 years; p < 0.05). Five patients had transplants, 1 patient was successfully bridged to recovery, and 15 patients remain on LVAD support. No patient with outflow closure developed regurgitation, embolization or compromised LVAD support. CONCLUSION Outflow tract closure in LVAD-supported patients is safe, often necessary and well tolerated.

Left ventricular assist device support of medically unresponsive pulmonary hypertension and aortic insufficiency

Most centers consider medically unresponsive pulmonary hypertension an absolute contraindication to orthotopic cardiac transplantation because the alternative surgical therapy, heterotopic graft placement, is associated with decreased survival, although most patients normalize their pulmonary hemodynamics postoperatively. Orthotopic transplantation in patients with elevated, but responsive pulmonary pressures, also is associated with an increased operative mortality rate and decreased long-term survival. The authors present the case of a patient with medically unresponsive pulmonary hypertension who was mechanically supported in an effort to improve his orthotopic transplant candidacy and decrease his risk. After informed consent, a HeartMate left ventricular assist device (LVAD) was inserted and the pulmonary hemodynamic response was monitored. Immediately before LVAD insertion, the pulmonary artery pressure (PA) was 74/28 mmHg with a transpulmonary gradient (TPG) of 28 mmHg, and a pulmonary vascular resistance (PVR) of 6.6 Wood units, despite prolonged dobutamine, milrinone, and prostaglandin E1 infusions. After 10 weeks of LVAD support, pressure and resistance improved; pulmonary artery pressure was 28/15 mmHg, transpulmonary gradient was 15 mmHg, and pulmonary vascular resistance was 2.8 Wood units. This patient subsequently underwent an uneventful orthotopic heart transplant. At 1 year after transplantation, pulmonary artery hemodynamics were normal (PA 34/14 mmHg, TPG at 8 mmHg, and PVR at 1.5 Wood units). The authors recommend the consideration of LVAD placement in patients with medically unresponsive pulmonary artery hypertension to assess PA responsiveness and improve the patients orthotopic cardiac transplant candidacy and decrease the operative risk. However, several weeks may be needed for normalization of pressure and resistance.

Right and left ventricular function after cardiac transplantation. Changes during and after rejection.

BackgroundAttempts to identify noninvasive markers of ventricular dysfunction accompanying acute rejection have been hampered by a lack of detailed simultaneous hemodynamic data. Therefore, we prospectively performed serial monitoring of detailed left and right heart hemodynamic parameters in cardiac transplant recipients at the time of routine endomyocardial biopsy to better define the physiology of the allograft heart during and after acute rejection. Methods and ResultsTo better assess the pathophysiology of the rejection process, 18 cardiac transplant patients were prospectively studied by serial right heart micromanometer catheterization and digital image processing at the time of routine endomyocardial biopsy. Eleven patients had 18 episodes of rejection. Studies of baseline (negative biopsy preceding rejection), rejection (acute moderate rejection), and resolved (first negative biopsy after rejection) states were compared. Seven patients who did not experience an episode of rejection served as the control group. Right ventricular minimum and end-diastolic pressures increased from baseline values of 0.9 % 3.2 and 6.9 ± 3.7 mm Hg, respectively, to 3.2 % 5.5 and 9.9 ± 6.6 mm Hg, respectively, with rejection (both variables, p < 0.05) and remained elevated despite histological resolution of rejection (4.3 ± 5.5 and 10.0 ± 7.1 mm Hg, respectively; p < 0.05 for both variables compared with baseline values). Concurrently, right ventricular end-diastolic volumes (133 % 29, 119 ± 27, and 114 ± 30 ml; baseline, rejection, and resolved, respectively) and left ventricular end-diastolic volumes (133 % 24, 117 % 20, and 113 ± 30 ml; baseline, rejection, and resolved, respectively) significantly decreased during rejection and remained decreased after resolution of rejection (rejection and resolved compared with baseline values, p < 0.05). Right ventricular chamber stiffness (0.055 ± 0.035,0.085 ± 0.057, and 0.092 ± 0.076 mm Hg/ml; baseline, rejection, and resolution, respectively; rejection and resolved compared with baseline values, p < 0.05) increased with rejection and remained elevated after resolution of rejection. Right ventricular peak filling rate also increased from a baseline value of 2.48 % 0.45 to 2.76 % 0.63 ml end-diastolic volumes per second with rejection (p < 0.05). Elevation of right ventricular filling pressures, peak filling rate, and chamber stiffness with a concomitant decrease in end-diastolic volume is consistent with a restrictive/constrictive physiology. Mean arterial blood pressure and systemic vascular resistance were elevated after the resolution of rejection (compared with either rejection or baseline values, p < 0.05) associatedwith a higher mean daily dose of prednisone (resolved compared with either baseline or rejection values, p < 0.0S). The control group experienced a time-dependent increase in mean and diastolic systemic arterial pressures (both comparisons, p < 0.05) without detectable diastolic dysfunction. ConclusionsPersistence of biventricular diastolic dysfunction may be due to an irreversible effect of rejection, although multifactorial changes in left ventricular afterload occur that may complicate serial assessment of ventricular function.

Exercise hemodynamics during long-term implantation of a left ventricular assist device in patients awaiting heart transplantation

OBJECTIVES The goal of this study was to assess patients with end-stage heart disease after implantation of a left ventricular assist device at rest and during exercise compatible with activities of daily life. BACKGROUND Mechanical circulatory assistance with a left ventricular assist device is an accepted therapy for bridging patients with end-stage heart disease to heart transplantation and has been proposed for long-term implantation. METHODS Three patients (aged 37, 42 and 57 years) with end-stage heart failure required implantation of a pneumatically driven, asynchronous Thermedics left ventricular assist device while awaiting heart transplantation. All were assessed 1 month later during graded supine bicycle exercise (maximal work load 100 to 150 W). Detailed central hemodynamics, including continuous pulmonary artery oxygen saturation and oxygen consumption measurements, were obtained. Two of the patients also underwent upright treadmill exercise with oxygen consumption measurements. RESULTS During supine bicycle exercise, the heart rate increased from 93 +/- 37 beats/min (95% confidence interval: mean +/- t0.025 x SE) at rest to 119 +/- 54 beats/min and left ventricular assist device rate increased from 82 +/- 47 to 109 +/- 55 beats/min. Oxygen consumption increased from 3.0 +/- 0.9 to 8.7 +/- 2.9 ml oxygen/min per kg body weight. Cardiac output increased from 6.0 +/- 4.4 to 9.6 +/- 7.1 liters/min, yielding an average exercise factor of 8.5 +/- 7.7 and an exercise index of 0.83 +/- 0.61. The patients assessed during treadmill exercise achieved a maximal oxygen consumption of 14.3 and 16.7 ml of oxygen/min per kg. No thromboembolic or other complications attributable to left ventricular assist device implantation occurred during the duration of support. All patients survived orthotopic heart transplantation and are doing well. CONCLUSIONS Significant work loads compatible with activities of daily life and adequate exercise hemodynamics were demonstrated by these patients while awaiting heart transplantation. Definitive conclusions regarding the use of this device must be viewed as preliminary because only three patients were involved in this study and the failure rate may be as high as 71% (95% confidence interval of left ventricular assist device success as a bridge to transplantation 29.3% to 100%). Final conclusions regarding the safety and efficacy of the left ventricular assist device as a possible long-term circulatory support device must await results of larger multicenter trials in progress.

Thromboembolism is linked to intraventricular flow stasis in a patient supported with a left ventricle assist device.

A case report is presented of a left ventricular assist device (LVAD) recipient with a pre-existing thrombus that was removed on LVAD implant but quickly reformed and was removed, reformed again, and ultimately embolized, causing death. The thrombus formed proximal to the left ventricular outflow tract, because of the presence and subsequent repair of a calcified left ventricular infarct which had extruded from the septum. This region is vulnerable to flow stasis during LVAD support as predicted by experimental fluid mechanics studies, because of the lack of opening of the aortic valve. The presence of the repair and the altered flow field contributed to blood stasis and thrombus growth in a positive feedback loop. Although LVADs provide tremendous benefits for patients by reducing the symptoms of heart failure, the accompanying changes have some secondary consequences that remain problematic. One of these is an abnormal intraventricular flow field that decreases washout, especially in the region proximal to the left ventricular outflow tract, which is an area of flow stasis.

Outcomes of volume-overloaded cardiovascular patients treated with ultrafiltration.

BACKGROUND Ultrafiltration (UF) can rapidly and predictably remove extracellular and intravascular fluid volume. To date, assessment of UF in patients with cardiovascular disease has been confined to short- and medium-term studies in patients with a principal diagnosis of acute heart failure. METHODS In-hospital and long-term outcomes were reviewed from consecutive patients with cardiovascular disorders and recognized pulmonary and systemic volume overload treated with a simplified UF system with the capability for peripheral venovenous access. Trained abstractors reviewed both paper and electronic medical records. Patients with a principal diagnosis of heart failure versus other primary hospital discharge diagnoses were identified according to International Classification of Diseases, 9th Revision standards by independent coders. RESULTS For a period of 43 months, 100 patients (76 male/24 female, 65 +/- 14.0 years of age, systolic dysfunction 64%) were treated with UF during 130 hospitalizations. Baseline systolic blood pressure was 119 +/- 23 mm Hg. Before UF, 53% were receiving intravenous vasoactive therapy. By using UF, 7.1 +/- 3.9 L of ultrafiltrate were removed during 2.0 +/- 1.2 treatments per hospitalization. Baseline creatinine was 1.8 +/- 0.8 and 1.9 +/- 1.2 (not significant) at discharge. Of the 15 in-hospital deaths, 14 occurred during the initial hospitalization. Left ventricular dysfunction was related to 13 (87%) of the 15 deaths; no deaths were related to UF use. In hospitalizations with a principal diagnosis of heart failure (n = 79), in-hospital mortality was 7.6% compared with an ADHERE risk tree estimated mortality of 7.5%. Multivariate logistic regression identified a trend for decreased systolic blood pressure to predict patient initial hospitalization mortality (P = .06). Kaplan-Meier survivals for all patients were 71% at 1 year and 67% at 2 years. Cox regression found decreased systolic blood pressure as a predictor of long-term mortality (P = .025). Total volume of ultrafiltrate removed, ejection fraction, history of coronary artery disease, creatinine clearance, gender, age, and principal diagnosis of heart failure were not significantly associated with long-term mortality. CONCLUSION This series extends the spectrum of patients previously reported to be treated with UF. Despite marked volume overload, UF-treated patients with a principal diagnosis of heart failure had inpatient outcomes similar to the ADHERE registry. UF should be considered for a broad range of patients who present with volume overload.

HeartMate left ventricular assist system exchange: results and technical considerations.

The duration times of left ventricular assist system (LVAS) support have increased because of prolonged wait times for transplant and the more frequent use of devices for destination therapy. The HeartMate LVAS, the only device approved for bridge to transplant and destination therapy, has limited durability, making replacement increasingly necessary. Since 1996, we have exchanged 19 left ventricular assist devices in 15 patients (11 men: mean age, 57.1 years; range, 33–77 years). Most of the devices (14) were replaced with the HeartMate vented electric/extended-lead vented electric pump; five devices were exchanged for a HeartMate II LVAS. Bearing failure was the most frequent reason for exchange (15 of 19 pumps); four of the 19 pumps also had active device-related infections at the time of exchange. There were no early deaths (30 days). Overall survival (Kaplan-Meier) was 85% at 1 year, 67% at 2 years, and 56% at 3 years. Three patients had transplants (mean, 518 days); six patients died during support (mean, 934 days), and six patients remain on LVAS support (mean, 1,219 days). One patient has been on device for over 6 years. Left ventricular assist devices exchange is becoming increasingly likely and can be associated with acceptably low-operative mortality rates and good intermediate-term survival.

Medically Unresponsive Pulmonary Hypertension: Heterotopic Cardiac Transplant Versus Mechanical Support

End-stage congestive heart failure with unresponsive pulmonary hypertension presents a unique clinical dilemma. Heterotopic graft placement is associated with decreased long-term survival and orthotopic transplantation carries high operative mortality. We report on a patient with unresponsive pulmonary hypertension who was mechanically supported with a HeartMate left ventricular assist device (LVAD). Immediately before LVAD insertion, the pulmonary artery pressure (PAP) was 74/28 mmHg with a transpulmonary gradient (TPG) of 28 mmHg, and a pulmonary vascular resistance (PVR) of 6.6 Wood units despite prolonged dobutamine, milrinone, and prostaglandin E1 infusions. After 10 weeks on the LVAD, these parameters were: PAP 28/15 mmHg, TPG 15 mmHg, and PVR 2.8 Wood units. The patient subsequently underwent an uneventful orthotopic heart transplant. At 1 year after transplantation, PAP remains low at 34/14, TPG at 8, and PVR at 1.5 Wood units. An LVAD bridge to orthotopic cardiac transplantation should be considered in selected patients with unresponsive pulmonary hypertension. However, several weeks may be needed for normalization of pressure and resistance.