J. Riebandt

Viennese approach to minimize the invasiveness of ventricular assist device implantation

OBJECTIVE Avoiding full sternotomy and cardiopulmonary bypass (CPB) could significantly reduce the invasiveness of left ventricular assist device (LVAD) implantation. Therefore, we developed minimally invasive implant strategies for the Heartware® VAD (HVAD) and the Thoratec® HeartMate II (HMII) covering isolated LVAD implantation as well as concomitant valve procedures (aortic/tricuspid). We present the surgical techniques and the initial clinical experience. METHODS From February 2012 to March 2013, 27 patients (mean age 58 ± 8 years; male 85%; Ischemic Cardiomyopathy 63%; redo surgery 22%; Interagency Registry for Mechanically Assisted Circulatory Support Level I: 29%, II: 22%, III: 33%, IV-VII: 16%) underwent minimally invasive LVAD implantation at our department. Apical cannulation was performed via a left lateral minithoracotomy in HVAD patients (n = 20) or a left subcostal incision in HMII patients (n = 7). The outflow graft anastomosis was performed to the ascending aorta via a right minithoracotomy in the second intercostal space (n = 22) or the right subclavian artery (n = 2). If additional valve procedures (aortic/tricuspid) were necessary (n = 3), a hemisternotomy was performed to access the valve and perform the outflow graft anastomosis. Circulatory support for LVAD implantation was CPB (33%), extracorporeal membrane oxygenation (48%) or off-pump (19%). RESULTS The minimally invasive approach was feasible in all patients with no need for conversions. Thirty-day and in-hospital mortality were 7.4 and 14.8%, respectively. In-hospital stay was 30.0 ± 22.5 days. One patient (4%) died during follow-up from pump thrombus formation. Three patients (11%) underwent surgical revision for bleeding. CONCLUSIONS Minimally invasive LVAD implantation is feasible and safe. The very encouraging results obtained in this initial series justify a broad application of this technique.

Preoperative patient optimization using extracorporeal life support improves outcomes of INTERMACS Level I patients receiving a permanent ventricular assist device.

OBJECTIVES Interagency Registry for Mechanical Assisted Circulatory Support (INTERMACS) Level I patients have the highest early mortality after ventricular assist device (VAD) implantation. This is determined by the exposure of patients in shock with acutely damaged end-organs and high catecholamine support to a significant surgical trauma. We report our experience with a bridge-to-bridge concept consisting of initial veno-arterial extracorporeal life support (ECLS) and deferral of VAD implantation to recovery of end-organ function in INTERMACS Level I patients. METHODS We reviewed the concept of initial ECLS implantation and deferral of VAD implantation to end-organ recovery in 22 consecutive patients (mean age 54 ± 14 years; 72.2% males; 50% ischemic cardiomyopathy; 100% INTERMACS Level I; 18.2% Heartmate II, 68.2% Heartware HVAD, 4.5% Heartware BiVAD, 9.1% DeBakey LVAD) receiving a VAD for refractory cardiogenic shock between June 2004 and February 2013. Study endpoints were end-organ recovery during ECLS and survival. RESULTS ECLS significantly improved renal (creatinine 1.86 ± 0.91 vs 1.32 ± 0.52 mg/dl, P = 0.02), hepatic (aspartate aminotransferase 1426 ± 2176 vs 277 ± 259 U/l, P = 0.04; alanine aminotransferase 982 ± 1466 vs 357 ± 447 U/l, P = 0.04) and pulmonary functions (fraction of inspired oxygen 52 ± 18 vs 26 ± 23%, P < 0.01; positive end-expiratory pressure 7 ± 3 vs 5 ± 4 mbar, P = 0.02) over a period of 8 ± 7 days. Catecholamines could be reduced during ECLS (levosimendan 0.056 ± 0.085 vs 0.010 ± 0.032 μg/kg/min, P = 0.06; dobutamine 4.362 ± 5.268 vs 0.056 ± 0.097 μg/kg/min, P = 0.06; noradrenaline 0.408 ± 0.355 vs 0.056 ± 0.097 μg/kg/min, P < 0.01). Thirty-day and in-hospital mortality after VAD implantation were 4.5 and 9.1%, respectively, and 1-year survival was 86.4%. CONCLUSIONS Preoperative patient optimization using ECLS improves outcomes of INTERMACS Level I patients receiving a permanent VAD.

Low-molecular-weight heparin for anti-coagulation after left ventricular assist device implantation

BACKGROUND Anti-coagulation is required in patients with left ventricular assist devices (LVADs). We evaluated the feasibility of low-molecular-weight heparin (LMWH) for initiation of anti-coagulation and transitioning to oral anti-coagulation after LVAD implantation. METHODS This single-center study included 78 consecutive patients who underwent either Thoratec HeartMate II LVAD (n = 27) or HeartWare ventricular assist device (HVAD, n = 51) implantation. The LMWHs enoxaparin (n = 50) and dalteparin (n = 28) were used. LMWH was started within 24 hours post-operatively in 79.5% of patients. No anti-coagulation was given before starting LMWH therapy. LMWH activity was monitored by determination of anti-factor Xa levels in plasma. RESULTS The majority of patients (80.7%) had peak anti-Xa activity within the defined range of efficacy of 0.2 to 0.4 IU/ml by the second day of treatment. Mean effective peak anti-Xa activity was 0.28 ± 0.06 IU/ml. Mean duration of anti-coagulation with LMWH was 25.8 ± 18 days. Ischemic strokes were observed in 3 patients (3.8%), with a total of 4 events. Three events occurred while on LMWH, and 1 event occurred during follow-up on oral anti-coagulation. There was 1 fatal stroke. No pump thrombus was observed. Major bleeding was observed in 5 patients (6.4%), with a total of 6 events. Gastrointestinal bleeding was the most common complication (n = 3). There were no fatal bleeding events. CONCLUSIONS LMWH in the setting of LVAD shows rapid and constant biologic efficacy. Anti-coagulation with LMWH appears feasible after LVAD implantation. These findings support further evaluation of LMWH as an alternative to unfractionated heparin in this patient cohort.

Off-Pump HeartWare Ventricular Assist Device Implantation With Outflow Graft Anastomosis to the Left Subclavian Artery

A novel, off-pump implantation technique for the HeartWare ventricular assist device with outflow graft anastomosis to the left subclavican artery is described. Cannulation of the left ventricular apex is performed through an incision in the left fourth or fifth intercostal space. The outflow graft is anastomosed to the left subclavian artery after tunneling through the left thoracic cavity and the first intercostal space. This technique is especially appealing in redo cases as well as in patients with significant calcifications of the ascending aorta or in destination-therapy patients.

Increased Thromboembolic Events With Dabigatran Compared With Vitamin K Antagonism in Left Ventricular Assist Device PatientsCLINICAL PERSPECTIVE

Background— Left ventricular assist device–supported patients are usually anticoagulated with a combination of aspirin and vitamin K antagonists. Long-term vitamin K antagonist therapy can be complicated by unstable international normalized ratio values and patient-related compliance problems. Therefore, direct thrombin inhibitors may represent an alternative to vitamin K antagonists. Methods and Results— Thirty HeartWare ventricular assist device patients with stable renal function were planned for this prospective, randomized, open-label, single-center study. Patients were randomized to receive either phenprocoumon or dabigatran in addition to aspirin for long-term anticoagulation. Treatment duration was scheduled for 1 year and stopped after observation of a primary end point. Dabigatran dose was 110 and 75 mg BID in patients with normal or impaired renal function (glomerular filtration rate >80 mL/min or between 80 and 30 mL/min, respectively). The study was stopped prematurely for safety reasons after 16 patients (61±8 years, 1 female) were randomized. Thromboembolic events occurred in 4 subjects receiving dabigatran (50%) and in 1 receiving phenprocoumon (13%; P=0.28). No major bleeding was recorded, and no patient died during the study. Median time to treatment termination was significantly shorter in dabigatran patients (8.5 versus 12.0 months; P=0.015). Conclusions— Thromboembolic events on dabigatran led to early termination of a randomized controlled trial of dabigatran versus phenprocoumon in left ventricular assist device patients. Clinical Trial Registration— https://www.clinicaltrials.gov. Unique identifier: NCT02872649.

Myocardial Recovery in Peripartum Cardiomyopathy After Hyperprolactinemia Treatment on BIVAD.

Peripartum cardiomyopathy (PPCMP) requiring mechanical circulatory support is rare; however, it is a life-threatening disease with recovery rates poorer than expected. Herein, we describe a case of successful recovery of a patient with PPCMP. Implantation of a biventricular ventricular assist device was performed; additionally, the patients hyperprolactinemia was treated with cabergoline, resulting in a fast complete restoration of ventricular function.

High-Intensity Transient Signals in the Outflow Graft and Thrombosis of a HeartWare Left Ventricular Assist Device

We report the echocardiographic detection of microbubbles in the outflow prosthesis of a HeartWare HVAD left ventricular assist device using transthoracic echocardiography. In this case it was a specific sign associated with device thrombosis that resolved after successful treatment with systemic thrombolysis.

Use of the Novel Surgical Enhancement Tools for Less Invasive Abbott HeartMate 3™ Implantation

This report presents an initial experience with the novel Abbott surgical enhancement tools for less invasive HeartMate 3 (Abbott, Chicago, IL) left ventricular assist system implantation. Three new devices are introduced: (1) a mini-apical cuff with (2) a cuff holder and (3) a newly designed coring knife, facilitating access through a left sided minithoracotomy.

Donor heart selection and outcomes: An analysis of over 2,000 cases

BACKGROUND Decision-making when offered a donor heart for transplantation is complex, and supportive data describing outcomes according to acceptance or non-acceptance choices are sparse. Our aim was to analyze donor heart acceptance decisions and associated outcomes at a single center, and after subsequent acceptance elsewhere. METHODS This investigation was a retrospective analysis of data obtained from the University of Vienna Medical Center and Eurotransplant centers for the period 2001 to 2015. RESULTS Our center accepted 31.8% (699 of 2,199) of donor hearts offered. Unlike other centers, the acceptance rate, with or without transplantation, did not increase over time. Of the donor hearts rejected by our center, 38.1% (572 of 1,500) were later accepted elsewhere. Acceptance rates were twice as high for donor hearts initially rejected for non-quality reasons (339 of 601, 56.4%) compared with initial rejection for quality reasons (233 of 899, 25.9%). Three-year patient survival rate was 79% at Vienna; for donor hearts initially rejected by Vienna for non-quality reasons or quality reasons, it was 73% and 63%, respectively (p < 0.001). Outcomes at other centers after transplantation of grafts rejected by Vienna varied according to the reason for rejection, with good 3-year survival rates for rejection due to positive virology (77%), high catecholamines (68%), long ischemic time (71%), or low ejection fraction (68%), but poor survival was observed for hearts rejected for hypernatremia (46%), cardiac arrest (21%), or valve pathology (50%). CONCLUSIONS A less restrictive policy for accepting donor hearts at our center, particularly regarding rejection for non-quality reasons or for positive virology, high catecholamine levels, longer ischemic time, or low ejection fraction, could expand our donor pool while maintaining good outcomes.

Extracorporeal membrane oxygenation support for right ventricular failure after left ventricular assist device implantation

OBJECTIVES Right ventricular (RV) failure complicating left ventricular assist device implantation is associated with increased mortality. Despite a lack of supporting evidence, venoarterial extracorporeal membrane oxygenation (ECMO) support is increasingly being used as an alternative to traditional temporary RV support. We report our institutional experience with ECMO-facilitated RV support after left ventricular assist device implantation. METHODS We retrospectively reviewed the concept of temporary ECMO support for perioperative RV failure in 32 consecutive left ventricular assist device (mean age 52 ± 14 years; male 84.4%; ischaemic cardiomyopathy 40.6%; INTERMACS Level I 71.8%; INTERMACS Level II 6.3%; INTERMACS Level III 12.5%; INTERMACS Level IV-VII 9.4%; HeartWare ventricular assist device 75%; HeartMate II: 25%) from May 2009 to April 2014. The study end points were RV recovery during ECMO support, mortality and causes of death. RESULTS Twenty-nine (90.6%) patients were successfully weaned from ECMO support after RV recovery. Three (9.4%) patients expired during ECMO support. ECMO support improved RV function and haemodynamic parameters (central venous pressure 13 mmHg vs 10 mmHg, P < 0.01; mean pulmonary artery pressure 28 mmHg vs 21 mmHg, P < 0.01; cardiac output 5.1 l/min vs 5.9 l/min, P = 0.09) over a median period of 3 (range 1-15) days. Thirty-day and in-hospital mortality were 18.8% and 25%, respectively. One-year survival was 75%, causes of death were multiorgan dysfunction syndrome (50%), sepsis (25%), haemorrhagic stroke (12.5%) and ischaemic stroke (12.5%). Causes of death during ECMO support were ischaemic stroke, sepsis and multiorgan dysfunction syndrome. CONCLUSIONS Temporary ECMO-facilitated RV support is associated with good long-term outcomes and high rates of RV recovery.