Assist Device Implantation Research Articles

Evaluation of Gastrointestinal Bleeding Following Implantation of Left Ventricular Assist Device (LVAD)

Evaluation of Gastrointestinal Bleeding Following Implantation of Left Ventricular Assist Device (LVAD)

Use of Minimized Extracorporeal Circulation System in Noncoronary and Valve Cardiac Surgical Procedures—A Case Series

The aim of this report is to explore application of minimized cardiopulmonary bypass (CPB) circuits in areas of cardiac surgery other than coronary bypass grafting and aortic valve surgery. We report three cases operated under minimal extracorporeal circulation support. Replacement of the descending thoracic aorta was performed in two patients; one with a descending aortic aneurysm and one with pseudoaneurysm formation after previous coarctation repair. We have also implanted a left ventricular assist device for destination therapy. The minimized extracorporeal circulation system provides optimal circulatory support, while it is associated with reduced postoperative morbidity, minimizing the side effects from the use of CPB. Moreover, when off-pump technique is attempted, it can be used as a standby circuit connected to the patient so as to enhance safety of the procedure. Minimized extracorporeal circulation systems can be used with safety and efficacy in a wide range of cardiac surgeries including descending aorta pathology and assist device implantation.

643 Predictors of Renal Function Improvement Following Implantation of Continuous Flow Left Ventricular Assist Device

Purpose: Chronic renal failure requiring dialysis has traditionally been an exclusion criterion for mechanical circulatory support in clinical trials and in clinical practice. Nephrology is actively involved in our VAD program and has been supportive of VADs in chronic dialysis patients. Outcomes with outpatient dialysis of VAD patients have not been described. We describe a single center experience with pre-existing chronic dialysis on VAD patients as a bridge to transplant. Methods and Materials: All VAD patients on chronic dialysis pre-VAD at Aurora St. Luke’s Medical Center were included. There have been no destination therapy patients on dialysis pre-VAD. Outcomes of interest include survival to transplant or 11/10/10, length of stay post-VAD, duration of support on dialysis, readmission rates, and ability to wean off dialysis. Results: 5 patients on chronic dialysis prior to VAD for 433 265 days have been implanted with a HM II with a length of stay of 22 8 days. All 5 have either survived to transplant or are on ongoing support for a duration of VAD support of 159 94 days. 3 patients were on hemodialysis and 2 on peritoneal dialysis. One patient was successfully weaned from dialysis 9 days post VAD and another did not require any dialysis post-VAD. Neither required renal transplant. The 3 patients who remained on dialysis post-VAD were supported for 110 66 days. There were only 4 re-admissions in 3 patients at 115 134 days post-VAD for a driveline infection, peritonitis, VT, and weakness. After the initial discharge, patients remained outpatients 97 3% of total days. Conclusions: 1) Carefully selected ESRD patients on dialysis may be suitable VAD candidates. 2) Peritoneal dialysis can be performed safely if no surgical invasion of the peritoneum occurs. 3) Outpatient hemodialysis can be safely performed on continuous flow VADs. 4) Outcomes, readmission rates, and length of stay appear to be similar to those reported in the literature for patients without ESRD. 5) After the initial discharge, 97% of days are spent out of hospital in VAD patients on dialysis

274 Arrhythmias in Patients with Cardiac Implantable Electrical Devices (CIED) Following Implantation of a Left Ventricular Assist Device (LVAD)

274 Arrhythmias in Patients with Cardiac Implantable Electrical Devices (CIED) Following Implantation of a Left Ventricular Assist Device (LVAD)

276 Demonstration of Hypercoagulability after Implantation of the HeartWare Ventricular Assist Device by Using Thromboelastography

Purpose: Consensus regarding the optimal strategy for setting left ventricular assist device (LVAD) speed has not been achieved, and optimal settings may differ between rest and exercise. We report a method for LVAD optimization at rest and with low intensity exercise using gas exchange analysis. Methods and Materials: 11 patients 3 months following implant of HeartMate II LVAD were studied using the SHAPE System (Shape Medical Systems, St. Paul, MN), which has previously been used for cardiac resynchronization therapy (CRT) optimization using gas exchange analysis. Five LVAD speeds were tested in each patient (clinically set baseline, 400, 200, 200, and 400 rpm); both at rest and with low intensity treadmill exercise (1-2 mph with 0-1% grade). Continuous partial pressure of end-tidal carbon dioxide (PETCO2) and ventilatory drive (defined as tidal volume/inspiratory time [VT/Ti]) were measured at each condition at two-minute increments; data from the last 30 seconds of each stage were analyzed. Results: Mean differences detected in PETCO2 and ventilatory drive were 2.1 0.8 mm Hg and 127 64 mL/s at rest and 2.0 0.8 mm Hg and 188 78 mL/s with exercise, respectively. There was poor agreement between clinically selected speed setting with “optimal” PETCO2 and VT/Ti-based settings. The clinical setting matched the “optimal” PETCO2 and VT/Ti setting in only 2/11 and 0/11 of patients at rest, and 3/11 and 7/11 of patients during exercise, respectively. On a per-patient basis, PETCO2 and VT/Ti-based optimal settings correlated in 7/11 of patients at rest and 5/11 during exercise. Using gas exchange-based optimization it was noted that the optimal setting at rest and exercise was different in 9/11 patients using either PETCO2 or VT/Ti. Conclusions: This pilot study suggests that gas exchange-based LVAD optimization can discriminate physiologically significant differences in gas exchange, and is frequently different than clinically determined settings. Furthermore, optimal LVAD settings at rest and with exertion often differ when measured objectively using gas exchange.

Use of methylene blue in the treatment of refractory hypotension after assist device implantation: report of five consecutive cases

Use of methylene blue in the treatment of refractory hypotension after assist device implantation: report of five consecutive cases

Hybrid approach of ventricular assist device and autologous bone marrow stem cells implantation in end-stage ischemic heart failure enhances myocardial reperfusion

We challenge the hypothesis of enhanced myocardial reperfusion after implanting a left ventricular assist device together with bone marrow mononuclear stem cells in patients with end-stage ischemic cardiomyopathy. Irreversible myocardial loss observed in ischemic cardiomyopathy leads to progressive cardiac remodelling and dysfunction through a complex neurohormonal cascade. New generation assist devices promote myocardial recovery only in patients with dilated or peripartum cardiomyopathy. In the setting of diffuse myocardial ischemia not amenable to revascularization, native myocardial recovery has not been observed after implantation of an assist device as destination therapy. The hybrid approach of implanting autologous bone marrow stem cells during assist device implantation may eventually improve native cardiac function, which may be associated with a better prognosis eventually ameliorating the need for subsequent heart transplantation. The aforementioned hypothesis has to be tested with well-designed prospective multicentre studies.

Development of Aortic Regurgitation/Insufficiency Following Implantation of Continuous Flow Left Ventricular Assist Device (LVAD) and Outcomes

Development of Aortic Regurgitation/Insufficiency Following Implantation of Continuous Flow Left Ventricular Assist Device (LVAD) and Outcomes

Right ventricular recovery after cervical extra corporeal membrane oxygenation in a four-month-old male leading to left Berlin Heart Excor assistance

A 4-month-old male with cardiogenic shock was implanted with cervical extracorporeal membrane oxygenation (ECMO). He had a biventricular heart failure associated to multiple organ failure (MOF). Right ventricular (RV) function and MOF recovered during five days ECMO leading to left ventricular assistance device (LVAD) implantation. This case shows the advantages of the double bridge strategy providing intervention time for complications refractory to VAD implantation and evaluation time of right and left ventricular function for potential mono- or bi-VAD implantation. Furthermore, there are no reports describing this strategy in young children leading to RV function recovery and its advantage.

Successful Implantation of a Left Ventricular Assist Device After Treatment With the Paracor HeartNet

The Paracor HeartNet, a ventricular constraint device for the treatment of heart failure (HF), is implanted through a left lateral thoracotomy. It envelopes the heart like a mesh "bag." This method of application raises the question of whether adhesions with the pericardium allow the safe implantation of a left ventricular assist device (LVAD) if HF worsens. A male patient who had undergone implantation of the Paracor HeartNet 42 months earlier presented with advanced HF for cardiac transplantation. The patient's condition deteriorated, and because no suitable organ for transplantation was available, implantation of an LVAD became necessary. Surgery was performed via a median sternotomy without complications. No severe adhesions were found. This is the first report on "how to do" LVAD implantation after Paracor HeartNet implantation with images and information about cutting the constraint. Because the Paracor HeartNet is "wrapped" around the heart, concerns persist that severe adhesions with the pericardium might occur. In this case, LVAD implantation after therapy with the Paracor HeartNet was without complications, and the expected massive adhesions were absent.

375: Impact of Ventricular Assist Device (VAD) Implantation on Clinical and Economic Outcomes of Heart Transplantation (HT) in the United States (US) from 2001-2006

375: Impact of Ventricular Assist Device (VAD) Implantation on Clinical and Economic Outcomes of Heart Transplantation (HT) in the United States (US) from 2001-2006

534: Major Neurological Events after Ventricular Assist Device (VAD) Implantation Are Device Specific but Are Also Related to Pre-Implant Factors

534: Major Neurological Events after Ventricular Assist Device (VAD) Implantation Are Device Specific but Are Also Related to Pre-Implant Factors

58: Thyroid Deficiency Is Common in Advanced Heart Failure and Associated with Increased Operative Mortality after Assist Device Implantation

58: Thyroid Deficiency Is Common in Advanced Heart Failure and Associated with Increased Operative Mortality after Assist Device Implantation

Second Harmonic Echocardiography and Spontaneous Contrast During Implantation of a Left Ventricular Assist Device

Implantable mechanical left ventricular assist devices (LVADs) are used as a bridge or alternative to heart transplantation. Peroperative transesophageal echocardiography is commonly applied during implantation. Significant air embolism may occur as a result of air leakage at connections and anastomoses when LV filling becomes inadequate, and this must be prevented. Early suspicion and detection of air is mandatory to avoid negative circulatory effects. We hypothesized that monitoring of heart chamber size and occurrence of single air bubbles using second harmonic imaging (SHI) echocardiography may prevent risk for significant air embolism. After implantation of the LVAD in 10 calves, invasive hemodynamic monitoring and epicardial SHI were performed while increasing pump speed. Air bubbles in the ascending aorta were monitored and the left heart visualized for off-line dimensional analysis. Detection of air bubbles in the ascending aorta preceded their appearance in the left ventricle. They occurred exclusively but not always after a decrease in left atrial (LA) size. Decrease in LA pressure did not predict bubble detection or reduction in LA size. We conclude that SHI detects spontaneous ultrasound contrast during implantation of a LVAD and that a decrease in LA size is a warning that air embolism is imminent.

Renal Recovery after Implantation of a Left Ventricular Assist Device: The “Hibernating Kidney”

Renal Recovery after Implantation of a Left Ventricular Assist Device: The “Hibernating Kidney”

In Vivo Preclinical Anticoagulation Regimens After Implantation of Ventricular Assist Devices

Ventricular assist devices (VADs) have demonstrated successfully their ability to treat failing circulation of patients with end-stage heart failure. Among the main obstacles with these VADs is thromboembolic events that increase device-related morbidity and mortality. Prior to the clinical application of any newly developed VAD, the feasibility of the device is tested on animal models. Animal species have different hemostatic properties than human patients, and this factor creates a margin of error when comparing the occurrence of VAD-induced thrombosis in an animal versus a human. This detailed literature review provides a thorough documentation of various preclinical anticoagulation protocols used to date, including their outcomes and recommendations for future anticoagulation management strategies. In summary, the outcomes favor a sheep or pig model over other animal models, and discourage the application of a single anticoagulative agent to improve outcomes with any of the currently available devices.

Novel Transaortic Double Barrel Ventricular Cannula

A novel transaortic ventricular cannula, known as the ‘double barrel’ cannula (DBC), is designed to minimize the invasiveness of Ventricular Assist Device (VAD) implantation by combining the inlet and outlet cannulae into a single dual lumen cannula. Both flows will pass through a single opening in the apex of the Left Ventricle with the outflow then continuing past the aortic valve, into the aortic arch. This design offers several potential advantages over the current state-of-the-art. These include less invasive surgery and providing mechanical support to the septum. By routing the outflow through the aortic valve, the need to access the external structure of the ascending aorta is eliminated thereby eliminating the need for open heart surgery. In determining the DBC's design, close attention has been paid to the outflow portion of the cannula, which passes through the aortic valve. It was anticipated that this portion of the DBC could have the largest impact on the device's usability in practice. The object of this study was to test the performance of the valve with the cannula passing through it. Three different geometries are circular, equilateral triangular, and one-third semicircular. Experiments measuring aortic insufficiency during the diastolic phase were conducted. The experiment was designed to analyze several geometries passing through an aortic valve under diastolic flow conditions. All experiments used a simple flow loop which allows a natural porcine aortic valve to be viewed from downstream. The loop was driven with a pneumatic ventricular simulator in order to produce a cyclic flow. Three cannulae cross-sections were molded from RTV11 Silicone. During this test, High Speed Cinematography and flow rate measurement were used to quantify valve sealing and leakage. All data was collected and analyzed for the three cross-sectional geometries during diastole. The performances of the three geometries were compared using American Heart Association guidelines of aortic insufficiency (Al) diagnosis. The flow rate data was integrated in order to determine the volume of ventricle ejection and valve regurgitation. All three geometries exhibit low and acceptable levels of Al (⩽15%Al), with the circular geometry causing the least amount of Al at 7.1%. The experimental control (Porcine aortic valve with no cannulae) exhibited an Al or 2.4%, validating both the harvested aortic valve and experimental flow loop for further testing. Using the high speed cinematography, several phenomena were observed during the sealing of the porcine valve; including leaflet folding leaflet bunching, and cannula displacement due to valve closure.

222: Prospective Study on Development of Quality of Life and Exercise Tolerance after Implantation of Left Ventricular Assist Devices

222: Prospective Study on Development of Quality of Life and Exercise Tolerance after Implantation of Left Ventricular Assist Devices

Clinical outcome after implantation of pulsatile versus non pulsatile left ventricular assist devices

Objective: We analysed the differences in clinical outcome after implantation of pulsatile and non-pulsatile Left Ventricular Assist Devices (LVAD). Methods: Between 01/1998–09/2007 61 patients (age 53±12y, range 16–78y) were treated for acute LV failure with implantation of a LVAD. Two groups were selected according to the type of pump flow: Group I (pulsatile LVAD (n=39) including HeartMate I, Thoratec LVAD, Medos, Novacor) and group II (nonpulsatile LVAD (n=21) including Jarvik 2000, Heartmate II, Ventrassist, Incor). Follow-up parameters were analysed preoperatively and at day 30 after implantation: Creatinine, Bilirubin, GPT, ventilation time, tracheotomy rate and need for dialysis. Results: Duration of support was 212±178d (range 6–681d) in group I and 313±555d (range 5–2403d) in group II. 30-days mortality was 13% (5/39) in group I and 15% (3/21) in group II. Creatinine levels reached pre-op values 30d after LVAD implantation in both groups (1.4±0.6mg/dl, 1.0±0.4mg/dl, respectively). 38% (15/39) had to be dialysed in group I versus 5% (1/21) in group II. There was no difference in ventilatory support (group I: 257±458h, median 48h; group II: 107±197h, median 30h). In group I, 8 pts. (20%) needed reintubation due to respiratory failure versus 6 pts. (31%) in group II. Tracheotomy-rate was higher in group I (20% (8/39) versus 14% (6/21), respectively). Bilirubin-levels were higher in group II 30d after implantation (2.6±5.0 and 1.0±2.8mg/dl, respectively) with no significant difference in GPT values. Conclusion: Clinical outcome after implantation of a nonpulsatile LVAD is similar to that after implantation of a pulsatile LVAD.

Implantation of a Left Ventricular Assist Device in a Patient With Primary Antiphospholipid Syndrome

The antiphospholipid syndrome is characterized by arterial and venous thrombosis and is associated with the presence of circulating antiphospholipid antibodies. Arterial thrombosis can result in myocardial infarction, which may potentially lead to end-stage heart failure. Here we report our anticoagulation protocol for patients with antiphospholipid syndrome that undergo axial-flow left ventricle assist devices (HeartMate II; Thoratec, Pleasanton, CA) implantation.