Experience with a standardized protocol to predict successful explantation of left ventricular assist devices.

OBJECTIVE: Patients with a continuous-flow left ventricular assist device may show recovery of myocardial function with unloading. Identifying candidates for and predicting clinical and hemodynamic stability after left ventricular assist device explantation remain challenging. METHODS: Retrospective analysis of patients who underwent evaluation for left ventricular assist device explantation following a standardized protocol from January 2016 to March 2020. Patients who met screening criteria underwent echocardiography under "baseline," "minimal net flow," and "pump stop" conditions. If the protocol criteria were met, right heart catheterization with left ventricular assist device stoppage and occlusion of the outflow graft with a balloon catheter were performed. In patients with pulmonary capillary wedge pressure less than 16 mm Hg, explantation was performed under "pump stop" conditions. RESULTS: A total of 544 patients were screened. Of these, 57 (10.5%) underwent a total of 73 echocardiography under "baseline" "minimal net flow" and "pump stop" conditions and 46 underwent left ventricular assist device stoppage and occlusion of the outflow graft with balloon catheter maneuvers. Complications during the procedure were rare. Ultimately, 21 patients (3.9%) underwent explantation. The left ventricular ejection fraction at baseline was 55.5% ± 6.5%. The mean pulmonary capillary wedge pressure was 8.1 ± 2.6 mm Hg and increased to 10.7 ± 2.9 mm Hg under left ventricular assist device stoppage and occlusion of the outflow graft with a balloon catheter. A nonischemic cause of cardiomyopathy was more likely to be found in patients who underwent explantation (20/21 patients [95%], P = .020). The survival 1 year after explantation was 95.2%, with 1 death occurring 222 days after left ventricular assist device explantation. At follow-up (median 24.9 months [interquartile range, 16.4-43.1 months]), patients were in New York Heart Association class 1 (61.9%), 2 (28.6%), and 3 (9.5%). CONCLUSIONS: Our 4-year experience with a standardized protocol for left ventricular assist device explantation showed a low rate of adverse events. If all criteria are met, explantation can be performed safely and with an excellent survival and functional class.

Diagnosis and Treatment Strategies of Outflow Graft Obstruction in the Fully Magnetically Levitated Continuous-Flow centrifugal Left Ventricular Assist Device: A Multicenter Case Series.

Outflow graft obstruction in left ventricular assist devices (LVADs) is a rare complication whose clinical presentation may be subtle. We present six cases of outflow graft obstruction in patients on HeartMate 3 LVAD detected between 648 and 1,222 days on support. Detection principles are described and treatment strategies discussed. Three patients were successfully managed with stents, one underwent surgical revision, one patient died despite emergency treatment, and the last patient without symptoms was listed for heart transplantation.

Longest Ongoing Support (13 Years) with Magnetically Levitated Left Ventricular Assist Device.

Implantation of a left ventricular assist device (LVAD) is an established treatment in end-stage heart failure. The longevity of LVAD support systems remains uncertain to a great extent because patients usually undergo transplantation, are weaned or die while on support before the maximum service life of these pumps is reached. We report about the hitherto longest published and still ongoing LVAD support of a 65 year old patient who received an Incor LVAD (Berlin Heart, Berlin, Germany, produced 2002-2018) 13 years ago. After pump exchange due to driveline damage, the patients were discharged home.

Two implantable continuous-flow ventricular assist devices in a biventricular configuration: technique and results.

OBJECTIVES: No continuous-flow right ventricular assist device for long-term support is available at the moment. Two continuous-flow ventricular assist devices used in a continuous-flow biventricular assist device configuration is an emerging option which has proven its feasibility but still is not approved for routine use. We present our technique and results of modifying the left ventricular assist device and making it suitable for right ventricular support. METHODS: Between September 2009 and October 2017, 39 patients received implantation of a continuous-flow ventricular assist device for right ventricular support in a continuous-flow biventricular assist device configuration. For implantation of the HeartWare® manufacturers name of the pump HeartWare HVAD pump (HVAD)® centrifugal ventricular assist device, we performed 2 major modifications: banding of the outflow graft and reducing the intracaval length of the inflow cannula. The HVAD® could be safely implanted into the right atrium or ventricle. The HeartMate 3® left ventricular assist device needed no banding, but we increased the extraventricular part of the inflow cannula. RESULTS: The overall 30-day survival for the group receiving primarily a continuous-flow biventricular assist device was 72.7% (9.5% standard error of the mean (SEM)), and the 1-year survival was 45.0% (10.7% SEM). The overall 30-day survival for the group receiving a subsequent pump for right ventricular support in a continuous-flow biventricular assist device configuration after temporary right ventricular support was 71.4% (12.1% SEM), and 1-year survival was 40.8% (13.6% SEM). CONCLUSIONS: At the moment, there is a lack of a continuous-flow right ventricular assist device especially designed and approved for right ventricular support. Therefore, modifications in continuous-flow ventricular assist devices designed for the left ventricle are done to make them suitable for right ventricular support. However, more information is needed regarding the optimal surgical technique, patient selection and the optimal time point of implantation.

Left Ventricular Assist Devices: Challenges Toward Sustaining Long-Term Patient Care.

Over the last few decades, the left ventricular assist device (LVAD) technology has been tremendously improved transitioning from large and noisy paracorporeal volume displacement pumps to small implantable turbodynamic devices with only a single transcutaneous element, the driveline. Nevertheless, there remains a great demand for further improvements to meet the challenge of having a robust and safe device for long-term therapy. Here, we review the state of the art and highlight four key areas of needed improvement targeting long-term, sustainable LVAD function: (1) LVADs available today still have a high risk of thromboembolic and bleeding events that could be addressed by the rational fabrication of novel surface structures and endothelialization approaches aiming at improving the device hemocompatibility. (2) Novel, fluid dynamically optimized pump designs will further reduce blood damage. (3) Infection due to the paracorporeal driveline can be avoided with a transcutaneous energy transmission system that additionally allows for increased freedom of movement. (4) Finally, the lack of pump flow adaptation needs to be encountered with physiological control systems, working collaboratively with biocompatible sensor devices, targeting the adaptation of the LVAD flow to the perfusion requirements of the patient. The interdisciplinary Zurich Heart project investigates these technology gaps paving the way toward LVADs for long-term, sustainable therapy.

Surgical management of driveline infections in patients with left ventricular assist devices.

BACKGROUND AND AIM OF THE STUDY: Driveline infections in patients with implantable left ventricular assist devices (VAD) carry increasing risk for pump infection, thromboembolic events, decreased quality of life, and increased hospitalization. We report our experience with a surgical technique for refractory driveline infections without mediastinitis consisting of translocation and wrapping of the driveline with greater omentum tissue. METHODS: We retrospectively reviewed data of VAD patients who underwent surgical treatment by translocation and wrapping with omentum for severe chronic driveline infection. RESULTS: Thirteen patients were treated between January 2010 and October 2015; 12 (92%) were male, and the mean age was 56 ± 14 years. Ten patients (77%) were managed with driveline sheathing with omentum and repositioning with a new exit site, and three (23%), suffering from driveline fistula, with driveline covering with omentum maintaining the previous exit site. Three episodes of postoperative bleeding (23%) required surgical revision. Twelve patients (92%) were discharged from the hospital and one (8%) died. Nine patients (69%) were free from infection at the time of discharge, and three (23%) had recurrence of infection within the first postoperative year. Only four patients (31%) required admission to the intensive care unit; overall median hospital stay was 23 days (range 7-205 days). CONCLUSIONS: Driveline relocation with use of omentum is a feasible and effective procedure in selected cases of chronic severe driveline infection. The risk for perioperative bleeding should be taken into consideration and carefully monitored.

Surgical Treatment of Mediastinitis with Omentoplasty in Ventricular Assist Device Patients: Report of Referral Center Experience.

Mediastinitis is more frequent in patients with implantable ventricular assist devices (VADs) than in other cardiac surgery patients and carries significant mortality. We report our experience with a stepwise approach including aggressive debridement, jet lavage, vacuum assisted closure dressing, and finally coverage with well-vascularized and immune-active omental flaps in VAD patients with infective mediastinitis. We retrospectively collected and analyzed data of patients with continuous flow VAD who underwent plasty with the omental flap because of mediastinitis at Deutsches Herzzentrum Berlin between January 1, 2008 and October 30, 2015. Eight hundred forty-five patients underwent VAD implantation during the study period. Omentoplasty due to infective mediastinitis was performed in 17 cases. Nine had a HeartWare HVAD as left ventricular assist device (LVAD), three patients had two Heart-Ware HVAD as biventricular assist device (BIVAD), four had a HeartMate II LVAD device, and one patient had a Berlin Heart Incor LVAD. The microorganisms most frequently isolated from the sternal wound were Gram-positive Staphylococcus spp. Four cases of bleeding requiring surgical revision were recorded: three of intraabdominal and one of wound bleeding. Eight patients (47%) survived, whereas the other nine patients (53%) died. Sixteen (94%) required intensive care unit admission, and median hospital stay was 21 (1-182) days. Postoperative renal failure requiring dialysis and septic shock requiring vasopressors were associated with hospital mortality (p = 0.009 and p = 0.05, respectively). Early surgical treatment of mediastinitis after VAD implantation with omentoplasty is a valuable strategy in an otherwise dead-end situation. Bleeding should be meticulously controlled in these anticoagulated and fragile patients.

Paediatric mechanical circulatory support with Berlin Heart EXCOR: development and outcome of a 23-year experience.

This paper reviews the development and establishment of the Berlin Heart EXCOR® (BHE®) as a paediatric mechanical circulatory support and reports our entire experience with regard to indications, timing of implantation and explantation and outcome. The Berlin group reported the first successful paediatric bridge to transplantation using a pulsatile pneumatic paracorporeal biventricular assist device, the BHE®, in 1990 in an 8-year-old boy with end-stage heart failure and coarctation of the aorta. This experience prompted them to develop miniaturized pump systems for children through the company Berlin Heart Mediproduct GmbH. The development and production of BHE® to support paediatric patients with heart failure then began. Between 1990 and 2013, the BHE® has been implanted in 122 patients (median age 8.64 years, range 3 days to 17 years) with heart failure, who were inotrope-dependent or switched from extracorporeal membrane oxygenation support or had postcardiotomy low-output syndrome. Thirty-five patients were <1 year old (median 125 days). The aetiology of heart failure included cardiomyopathy in 56 (median age 9.14 years), fulminant myocarditis in 17 (median age 8.2 years), end-stage congenital heart disease in 18 (median age 6.4 years), postcardiotomy heart failure (after correction of congenital heart disease) in 28 (median age 9.6 years) and transplant graft failure in 3 (median age 12.5 years). The overall median duration of implantation was 63.6 (range 1-841) days. Fifty-six children eventually underwent orthotopic heart transplantation. Eighteen patients had myocardial recovery and were weaned successfully. They had entirely normal cardiac function after a range of 4-10 years after surgery. At the time of this report, five patients were still on support, with a duration of 354-369 days. Forty-three patients died on the system from loss of peripheral circulatory resistance, multiorgan damage, sepsis or haemorrhagic or thrombotic complications. Re-exploration because of bleeding was necessary in 22 patients. Pump exchange because of thrombus formation in the valves was necessary 35 times. With the introduction of a modified anticoagulation regimen in 2000, the pump exchange rate has decreased. The BHE® can reliably support the circulation at any age for long periods with good results. It is now an established treatment for children with heart failure of any aetiology.

Design changes in continuous-flow left ventricular assist devices and life-threatening pump malfunctions.

OBJECTIVES: The implantable continuous-flow left ventricular assist devices (LVADs) HeartMate II (HM II) and HeartWare HVAD (HW) underwent design modifications. The impact of these changes on life-threatening pump malfunctions was evaluated. METHODS: We retrospectively analysed pump malfunctions due to thrombosis or cable damage in patients supported with primarily implanted HM II (n = 191) and HW (n = 347), separated into patients supported with the old and new pump designs. In 2010, the cable strain relief of the HM II device was improved (132 patients with old and 79 with new) and sealed grafts were introduced (68 patients with sealed inflow connector and outflow graft and 125 without). In 2011, titanium sintering of the inflow cannula of HW pumps was introduced (137 patients with a non-sintered and 210 with a sintered inflow cannula). RESULTS: The median support time was 1.12 (0-6.1) years for all HM II and 0.59 (0-4.2) years for all HW patients. The cumulative rate of events per patient-year (EPPY) was 0.11 in HM II patients, compared with 0.09 EPPY in HW patients (P = 0.32). After introduction of the new cable design, incidence of cable damage in HM II patients dropped from 0.06 to 0 EPPY (P = 0.03), whereas pump thrombosis increased from 0.02 to 0.14 EPPY (P < 0.001) after the sealed graft was introduced. Pump thrombosis occurred in 4% of patients supported with HW with a sintered inflow cannula vs 15% with a non-sintered pump; the incidence changed from 0.10 to 0.07 EPPY in sintered pumps (P = 0.45). Kaplan-Meier analysis showed no differences over a period of 2.5 years for events when the HM II cohort with sealed graft and new cable design (n = 68) was compared with the HW group with a sintered cannula (P = 0.14). CONCLUSIONS: The modified cable strain relief of the HM II pump and the sintering of the inflow cannula of the HW pump demonstrated a significant reduction in the incidence of life-threatening pump-related complications, whereas the sealed inflow connector and outflow graft seem to be associated with a higher incidence of pump thrombosis. However, the overall incidence of pump-related complications after the latest design changes was similar for both pumps over a 2.5-year period.

Thrombosis and cable damage in the HeartWare pump: clinical decisions and surgical technique.

Exchange of the HeartWare HVAD made necessary by thrombosis or cable damage is rare, but it is a complex procedure associated with morbidity. Less invasive exchange procedures may contribute to faster postoperative recovery and early mobilization. Between September 2009 and April 2012, 225 patients (median age 55.4 years, range 7-82 years, 40 of them women) were supported with the HeartWare HVAD at our institution. Cumulative follow-up in all 225 patients was 151.9 patient/years. In six patients, early pump thrombosis (<30 days) requiring pump exchange occurred after a median time of 7 (2-9) days. In six patients, late pump thrombosis requiring pump exchange occurred after a median of 380 (84-705) days. The overall incidence was 5.3% with 0.079 thromboses per year. In two instances of accidental cable damage as a result of massive external mechanical impact, pump exchange was necessary. We describe a safe and less invasive technique for the explantation and exchange of the HeartWare HVAD through a left thoracotomy. Pump thrombosis of the HeartWare HVAD is a very rare condition caused mostly by new onset of heparin-induced thrombocytopenia type II, mismanagement of anticoagulation, or hypercoagulability in the case of severe sepsis. Since the introduction of the sintered inflow cannula no early thrombosis has occurred. Pump exchange in the case of hemolysis should not be delayed. The cable of the HeartWare HVAD is very reliable and breaks only after excessive external impact. A minimally invasive approach for pump exchange on cardiopulmonary bypass for pump thrombosis and off-pump for cable damage or pump explantation is recommended.

Retrospective hemolysis comparison between patients with centrifugal biventricular assist and left ventricular assist devices.

Little is known about the hemolysis rate in the case of concomitant implantation of two continuous flow pumps for the treatment of biventricular heart failure. We present a retrospective study comparing the hemolysis parameters in patients supported with one implantable centrifugal pump of the type HeartWare HVAD used as a left ventricular assist device (LVAD) and with two pumps as a biventricular assist device (BiVAD). A total of 20 consecutive patients who received HeartWare BiVAD (n = 10) and LVAD (n = 10) support at our institution between September 2009 and September 2010 were examined. Hemolysis- and anemia-related parameters were analyzed after 2 weeks, 5 weeks, 3 months, and 6 months of support. Preoperative levels of hemoglobin, lactate dehydrogenase (LDH), and total bilirubin were similar in both groups. There were no differences in LDH, plasma-free hemoglobin (fHB), or total bilirubin levels postoperatively for up to 6 months. Only the haptoglobin level was lower in BiVAD recipients up to 3 months after surgery: 2nd week (63.5 [range: 8-237] mg/dl vs. 151 [range: 11-263] mg/dl, p = 0.05), 5th week (67 [range: 8-196] mg/dl vs. 215 [range: 56-292] mg/dl, p = 0.046), and after 3rd month (42 [range: 8-205] mg/dl vs. 220 [range: 157-256] mg/dl, p = 0.048). Our retrospective analysis of BiVAD HeartWare and LVAD HeartWare recipients showed a lack of a clinically important degree of hemolysis when two centrifugal HeartWare pumps are used for biventricular support.

Improvement in survival after mechanical circulatory support with pneumatic pulsatile ventricular assist devices in pediatric patients.

BACKGROUND: Pediatric size pneumatically driven extracorporeal ventricular assist devices (VAD) for infants and small children were introduced into clinical routine in 1992. In the initial period, the results in infants were poor. Since then, several improvements have been introduced with regard to the cannulas, connectors, heparin coating of the blood pump inner surface, anticoagulant treatment and coagulation monitoring, and earlier decision-making in favor of pump implantation before irreversible shock has set in. METHODS: Since 1990 and as of January 1, 2005, 62 Berlin Heart Excor systems have been implanted in patients below 18 years of age at our institution. The patients were divided into two groups according to the period of treatment: period 1, devices implanted between 1990 and 1998 (n = 34), and period 2, devices implanted between 1999 and 2004 (n = 28). We compared our experience during the earlier and later periods. RESULTS: There were no significant differences in the preoperative patient data between the two periods except for time of support (17.9 +/- 27.7 days versus 53.2 +/- 83.9 days, p = 0.001). In period 1, more patients needed a biventricular VAD whereas in period 2, more patients were effectively treated with a left VAD (p = 0.05). In the later period, the chest could be primarily closed in a significantly higher percentage of infants (0% versus 89%, p = 0.012), and more infants could be extubated on the VAD (0% versus 55%, p = 0.16). Discharge from the hospital after either weaning from the system or heart transplantation was achieved for 35% in period 1 and for 68% in period 2 (p = 0.029). Whereas in period 1 there were no survivors in the group of children younger than 1 year old, during period 2, survival in this age group was similar to that of the two groups of older children (p = 0.024). There was a significant improvement in the discharge rate in period 2 in patients with cardiomyopathy (43% versus 76%, p = 0.045) and postcardiotomy heart failure (0% versus 57%, p = 0.01). CONCLUSIONS: Earlier implantation of VADs, heparin coating of the blood pumps, and substantial modifications in cannula design, anticoagulation, and the coagulation monitoring regimen have led to a significant increase in the survival and discharge rate, especially among children under 1 year of age. The pediatric size Berlin Heart Excor VAD is a valuable option as a bridge to heart transplantation or recovery for children suffering from cardiogenic shock.

Mechanical cardiac support in the young with the Berlin Heart EXCOR pulsatile ventricular assist device: 15 years' experience.

The pediatric-size pneumatically driven pulsatile extracorporeal ventricular assist device (VAD) Berlin Heart EXCOR (Berlin Heart Mediprodukt GmbH, Berlin, Germany) was introduced into clinical practice by the German Heart Institute Berlin in 1992. Until July 1, 2005, Berlin Heart EXCOR systems have been used for circulatory support in 68 children up to 18 years of age with severe circulatory failure resistant to pharmacologic therapy. These were patients suffering from cardiomyopathy, fulminant myocarditis, end-stage congenital cardiac defects, and acute heart failure following congenital heart surgery. Mean VAD support time was 35 days (range, 0 to 420 days). Forty-two patients (62%) survived to transplantation or after weaning; 37 patients (54%), including eight infants, were discharged home. These results in patients with very advanced disease have improved significantly in recent years because of technical developments and growing experience in the treatment of patients on the device, in postoperative care and optimal timing for VAD implantation. Timely implantation of the Berlin Heart EXCOR in the course of progressive heart failure now appears to be justified because the system has undergone the necessary modifications and the accumulation of clinical knowledge has made its use highly reliable and safe.