K. Dimitrov

Debate: creating adequate pulse with a continuous flow ventricular assist device: can it be done and should it be done? Probably not, it may cause more problems than benefits!

Purpose of review The feasibility and benefits of creating adequate pulsatility with continuous flow left ventricular assist devices (LVADs) have long been debated. This review discusses recent technical and clinical findings to answer whether such intervention should be implemented in the standard patient management. Recent findings Only a limited amount of pulsatility can be generated by periodic speed steps, both considerably smaller in flow increase and in pace rate than the natural circulation. Organ systems are not impeded in their normal function and even not in recovery by a continuous flow. Known problems such as gastrointestinal bleeding are not necessarily due to pulsatility per se, or not important for therapeutic progress, such as minor modifications of the arterial walls. Summary The speculative benefits of augmented pulsatility with continuous flow LVADs could be overrated and are still incompletely evaluated. Potential risks that might arise from this strategy should be carefully weighed before implementing extensive pulsatility as standard patient management.

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.

Organ Preservation During Open Thoracoabdominal Reconstruction

Abstract Surgical repair of thoracoabdominal aortic aneurysms continues to be a challenging and demanding task. Ischemic injury to the visceral organs and spinal cord remains the most severe complication during this extensive surgery. Several organ perfusion techniques have dramatically decreased the incidence of this serious intra- and postoperative complication.

Minimally invasive approaches for implantation of left ventricular assist devices

The era of intracorporal continuous flow pumps has initiated significant success of left ventricular assist device (LVAD) surgery. However, median sternotomy has been the only surgical approach for implantation over many years. During the last decade, less-invasive access ways gained popularity. Within this review, we describe our own clinical experience in minimally invasive ventricular assist device (VAD) surgery and summarize the current scientific literature on this topic.

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.

Long-term heart transplant outcomes after lowering fixed pulmonary hypertension using left ventricular assist devices†

OBJECTIVES Fixed pulmonary hypertension (fPH) is a contraindication for heart transplantation (HTX). Left ventricular assist device (LVAD) implantation as a bridge to candidacy can reverse fPH in patients with terminal heart failure by chronic left ventricular unloading. We report our institutional experience with terminal heart failure patients and fPH that were successfully bridged to candidacy and underwent subsequent HTX. METHODS We retrospectively reviewed the data of 79 patients with terminal heart failure and fPH who were successfully bridged to candidacy for HTX with 6 different LVAD devices at our centre from October 1998 to September 2016 (Novacor n = 4, MicroMed DeBakey n = 29, DuraHeart n = 2, HeartMate II n = 14, HVAD n = 29 and MVAD n = 1). Median duration of LVAD support was 288 days (range 45-2279 days). Within the same timeframe, a control group of 48 patients underwent HTX after bridge-to-transplant LVAD therapy for reasons other than PH. Study end points were (i) development of fPH after LVAD implantation, (ii) post-transplant outcomes and (iii) incidence of severe adverse events. RESULTS Pulmonary vascular resistance, assessed by vasodynamic catheterization, was 4.3 ± 1.8 WU before LVAD implantation. After a median support period of 89 days (interquartile range 4-156 days), pulmonary vascular resistance decreased to 2.0 ± 0.9 WU (P ≤ 0.001), and patients were listed for HTX. Median duration of LVAD support in the study group was 288 days (45-2279 days). We observed 2 patients (2.5%) with acute right heart failure who required extracorporeal mechanical support after HTX in the study group. Long-term post-transplant survival between the study group (3 years: 83.5%, 5 years: 81.0%) and the control group (3 years: 87.5%, 5 years: 85.4%) was comparable (log-rank: P = 0.585). CONCLUSIONS LVAD implantation as a bridge to candidacy reverses fPH in patients with terminal heart failure. Post-HTX survival is excellent and comparable to results obtained in patients without fPH at the time of HTX listing.

A Standardized Telephone Intervention Algorithm Improves the Survival of Ventricular Assist Device Outpatients: VAD TELEPHONE INTERVENTION ALGORITHM

Abstract Ventricular assist devices (VADs) are an established therapeutic option for patients with chronic heart failure. Continuous monitoring of VAD parameters and their adherence to guidelines are crucial to detect problems in an early stage to optimize outcomes. A telephone intervention algorithm for VAD outpatients was developed, clinically implemented and evaluated. During the phone calls, a structured inquiry of pump parameters, alarms, blood pressure, INR, body weight and temperature, exit‐site status and heart failure symptoms was performed and electronically categorized by an algorithm into 5 levels of severity. VAD outpatient outcomes without (n = 71) and with bi‐weekly telephone interviews in their usual care (n = 25) were conducted using proportional hazard Cox regression, with risk adjustment based on a propensity score model computed from demographics and risk factors. From February 2015 through October 2017, 25 patients (n = 3 HeartMate II, n = 4 HeartMate 3 and n = 18 HeartWare HVAD) underwent 637 telephone interventions. In 57.5% of the calls no problems were identified, 3.9% were recalled on the next day because of alarms. In 26.5% (n = 169), the VAD Coordinator had to refer to the physician due to elevated blood pressure (n = 125, >85 mm Hg), INR < 2.0 or > 4.0 (n = 24) or edema (n = 10), 11.9% of the calls led to a follow‐up because of equipment or exit‐site problems. Propensity‐adjusted 2‐year survival (89% vs. 57%, P = 0.027) was significantly higher for the telephone intervention group. Continuous, standardized communication with VAD outpatients is important for early detection of upcoming problems and leads to significantly improved survival.

Interventional Treatment of LVAD Outflow Graft Stenosis by Introduction of Bare Metal Stents.

Left ventricular assist device outflow graft stenosis is a rare but life-threatening complication of mechanical cirulatory support therapy. Current treatment modalities (pump exchange or systemic thrombolytic therapy) are associated with significant mortality and morbidity. Implantation of bare metal stents within the stenosed outflow graft is an alternative. Herein, we describe a series of three cases with successful stent placement. This seems to be safe and successful; however, correct and early diagnosis of outflow stenosis can be challenging. Information provided by the HeartWare ventricular assist device (HVAD) logfiles is extremely helpful for diagnosis.