Hematologic effects of continuous flow left ventricular assist devices. J Cardiovasc Transl Res. 2010;3:618-624. [PMID: 20835786 DOI: 10.1007/s12265-010-9222-6]

Multimodality imaging for the evaluation and management of patients with long-term (durable) left ventricular assist devices

Left ventricular assist devices (LVADs) are gaining increasing importance as therapeutic strategy in advanced heart failure (HF), not only as bridge to recovery or to transplant but also as destination therapy. Even though long-term LVADs are considered a precious resource to expand the treatment options and improve clinical outcome of these patients, these are limited by peri-operative and post-operative complications, such as device-related infections, haemocompatibility-related events, device mis-positioning, and right ventricular failure. For this reason, a precise pre-operative, peri-operative, and post-operative evaluation of these patients is crucial for the selection of LVAD candidates and the management LVAD recipients. The use of different imaging modalities offers important information to complete the study of patients with LVADs in each phase of their assessment, with peculiar advantages/disadvantages, ideal application, and reference parameters for each modality. This clinical consensus statement sought to guide the use of multimodality imaging for the evaluation of patients with advanced HF undergoing LVAD implantation.

Delayed versus primary sternal closure for left ventricular assist device implantation: Impact on mechanical circulatory support infections

BACKGROUND

Delayed sternal closure may be required after left ventricular assist device (LVAD) implantation due to coagulopathy or hemodynamic instability. There is conflicting data regarding infection risk.

METHODS

We performed a single-center, retrospective analysis of patients who received their first LVAD between May 2012 and January 2021. Patients were divided into delayed sternal closure (DSC) and primary sternal closure (PSC) groups. We used chi-squared or Fisher Exact tests, as appropriate, to compare the incidence of postoperative LVAD-related infections (mediastinal/sternal wound) and LVAD-specific infections (driveline and pump pocket) after definitive chest closure between these two groups.

RESULTS

A total of 327 patients met eligibility criteria, including 127 (39%) patients that underwent DSC and 200 (61%) patients that had a PSC. Demographic and clinical characteristics were similar except for an overrepresentation of men (87% vs. 75%, p = .016), Interagency Registry of Mechanically Assisted Circulatory Support class I-II patients (89% vs 66%, p < .001), patients with a previous sternotomy (43% vs 13%, p < .001), and patients with chronic kidney disease (55% vs 43%, p = .030) in the DSC group. The median DSC time was 24 (IQR: 24-48) hours. The incidence of LVAD-related mediastinal/sternal wound infection was similar between the DSC and PSC groups (4.7% vs 3.0%, p = .419). There was no difference between DSC and PSC groups in the incidence of driveline infection (6.3% vs 9%, p = .411) and pump pocket infection (1.6% vs 1.5%, p =.901), respectively.

CONCLUSIONS

DSC does not seem to increase the incidence of LVAD-related or LVAD-specific infection rates in heart failure patients undergoing device implantation surgery.

Decreased Platelet Specific Receptor Expression of P-Selectin and GPIIb/IIIa Predict Future Non-Surgical Bleeding in Patients after Left Ventricular Assist Device Implantation

Non-surgical bleeding (NSB) is one of the major clinical complications in patients under continuous-flow left ventricular assist device (LVAD) support. The increased shear stress leads to an altered platelet receptor composition. Whether these changes increase the risk for NSB is unclear. Thus, we compared the platelet receptor composition of patients with (bleeder group, n = 18) and without NSB (non-bleeder group, n = 18) prior to LVAD implantation. Blood samples were obtained prior to LVAD implantation and after bleeding complications in the post-implant period. Platelet receptor expression of GPIbα, GPIIb/IIIa, P-selectin and CD63 as well as intra-platelet oxidative stress levels were quantified by flow cytometry. Bleeders and non-bleeders were comparable regarding clinical characteristics, von Willebrand factor diagnostics and the aggregation capacity before and after LVAD implantation (p > 0.05). LVAD patients in the bleeder group suffered from gastrointestinal bleeding (33%; n = 6), epistaxis (22%; n = 4), hematuria or hematoma (17%; n = 3, respectively) and cerebral bleeding (11%; n = 2). Prior to LVAD implantation, a restricted surface expression of the platelet receptors P-selectin and GPIIb/IIIa was observed in the bleeder group (P-selectin: 7.2 ± 2.6%; GPIIb/IIIa: 26,900 ± 13,608 U) compared to non-bleeders (P-selectin: 12.4 ± 8.1%, p = 0.02; GPIIb/IIIa: 36,259 ± 9914 U; p = 0.02). We hypothesized that the reduced platelet receptor expression of P-selectin and GPIIb/IIIa prior to LVAD implantation may be linked to LVAD-related NSB.

Apixaban: Alternative Anticoagulation for HeartMate 3 Ventricular Assist Device

Patients with left ventricular assist devices currently require long-term anticoagulation with warfarin. Warfarin requires frequent blood tests and is associated with adverse events when not in the therapeutic range. Apixaban is a possible alternative that is potentially better for compliance and requires no additional testing. The purpose of this study was to compare adverse events in patients with a HeartMate 3 LVAD receiving apixaban versus warfarin. Thirty-five patients underwent HM3 implantation between January 01, 2016 to January 31, 2021. The groups compared were apixaban (n = 15, 43%) and warfarin (n = 20, 57%). All patients received 325 mg aspirin daily. Stroke, bleeding, and death were identified as primary outcomes after LVAD implant. Univariate nonparametric statistical analysis was performed. The median duration of treatment with apixaban was 148 days (37-606 days). The groups were comparable in terms of age (56 vs. 54 years), gender (male, 85% vs. 75%), and renal function (Cr 1.5 vs. 1.4). The apixaban group had significantly higher mean pulmonary artery pressure (41 vs. 34, p = 0.03) and there were more (p < 0.05) ischemic cardiomyopathy and INTERMACS profile >3 in the warfarin group. At 6 months, thrombotic complications and death were not different between the groups. The two deaths in the apixaban group were from right heart failure. The apixaban group had clinically lower rates of bleeding complications (5% vs. 30%). The adverse events of bleeding, stroke, and death were similar in HM3 patients receiving warfarin or apixaban. Apixaban may be a safe alternative anticoagulant therapy in HM 3 LVAD patients.

Medical and Surgical Management of Left Ventricular Assist Device-Associated Intracranial Hemorrhage

OBJECTIVES

Management of left ventricular assist device (LVAD)-associated intracranial hemorrhage (ICH) is complicated by the competing concerns of hematoma expansion and the risk of thrombosis. Strategies include reversal or withholding of anticoagulation (AC) and neurosurgical (NSG) interventions. The consequences of these decisions can significantly impact both short- and long-term survival. Currently no guidelines exist. We reviewed medical and NSG practices following LVAD-associated ICH and analyzed outcomes.

MATERIALS AND METHODS

Retrospective analysis of data collected between 2012-2018 was performed. Survival probability following ICH was calculated using the Kaplan-Meier method.

RESULTS

Out of 283 patients, 32 (11%) had 34 ICHs: 16 intraparenchymal (IPH, 47%), 4 subdural (SDH, 12%), and 14 subarachnoid (SAH, 41%). IPH tended to occur sooner (median 138 [IQR 48 - 258] days post-LVAD placement) and be more neurologically devastating (mean GCS 11.4 [4.4]). Antithrombotics were reversed in 27 (79%); 1 thrombotic event occurred while off AC. Following resumption, re-hemorrhage occurred in 7 (25%), a median of 13 days (IQR 8-30) post-ICH. Five underwent NSG intervention and 6 (18%) went on to receive heart transplant. Overall, 30-day mortality was 26% (38% in IPH, 0% in SDH, and 29% in SAH), but rose to 44% at 6 months.

CONCLUSION

ICH is a common post-LVAD complication with high short- and long-term mortality, though ICH subtypes may not be equally devastating. Despite this, some may benefit from neurosurgical intervention and do well following cardiac transplant. Anticoagulation is frequently reversed after ICH. Resumption however should be approached cautiously in patients with LVADs given their possible baseline coagulopathy.

Preoperative Right Heart Dysfunction and Gastrointestinal Bleeding in Patients with Left Ventricular Assist Devices

Gastrointestinal bleeding (GIB) is a common cause of morbidity among patients supported by left ventricular assist devices (LVADs). The aim of this study was to identify if pre-LVAD right ventricular (RV) dysfunction is associated with risk of GIB after LVAD implantation. Of 398 patients implanted with LVADs between July 2008 and July 2016, 130 (33%) developed GIB at a median of 2.6 months following LVAD implantation. Arteriovenous malformations (AVMs) were found in 42 (34%) GIB patients. Patients with GIB were older and more likely to have hypertension, diabetes, and ischemic cardiomyopathy. On pre-LVAD echocardiography, GIB patients had increased RV diastolic dimension (4.7 ± 0.8 vs. 4.4 ± 0.9 cm, p = 0.02), a higher rate of greater than mild tricuspid valve (TV) regurgitation (73 [60%] vs. 120 [47%], p = 0.006), and underwent TV repair more often (38 [30%] vs. 43 [16%], p = 0.0006) during LVAD implantation. After multivariable adjustment, preoperative greater than mild RV enlargement (hazard ratio [HR] 2.32, 95% CI 1.12-5.03; p = 0.03), TV regurgitation (HR 1.83, CI 1.02-3.44; p = 0.01), and TV repair (HR 3.76, confidence interval [CI] 1.02-4.44; p = 0.01) remained associated with risk of GIB. This finding was driven by the AVM-GIB subgroup. Preoperative RV enlargement and TV regurgitation are associated with post-LVAD AVM-related GIB.

The Use of Factor Eight Inhibitor Bypass Activity (FEIBA) for the Treatment of Perioperative Hemorrhage in Left Ventricular Assist Device Implantation

OBJECTIVE

To test the hypothesis that factor eight inhibitor bypassing activity (FEIBA) can be used to control bleeding following left ventricular assist device (LVAD) implantation without increasing the 14-day composite thrombotic outcome of pump thrombus, ischemic cerebrovascular accidents, pulmonary embolism, and deep venous thrombosis.

DESIGN

Retrospective cohort study.

SETTING

Academic hospital.

PARTICIPANTS

Three hundred nineteen consecutive patients who underwent LVAD implantation (December 1, 2009 to December 30, 2018).

INTERVENTION

FEIBA administered to control perioperative hemorrhage.

MEASUREMENTS AND MAIN RESULTS

The 82 patients (25.7%) in the FEIBA cohort had more risk factors for perioperative hemorrhage, such as lower preoperative platelet count (169 ± 66 v 194 ± 68 × 10³/mL, p = 0.004), prior cardiac surgery (36.6% v 21.9%, p = 0.008), and longer cardiopulmonary bypass (CPB) time (100.3 v 75.2 minutes, p = 0.001) than the 237 controls. After 16.6 units (95% CI: 14.3-18.9) of blood products were given, 992 units (95% CI: 821-1163) of FEIBA were required to control bleeding in the FEIBA cohort. Compared to the controls, there were no differences in the 14-day composite thrombotic outcome (11.0% v 7.6%, p = 0.343) or mortality rate (3.7% v 1.3%, p = 0.179). Multivariate logistical regression identified preoperative international normalized ratio (odds ratio [OR]: 1.30, 95% CI: 1.04-1.62) and CPB time (OR: 1.11, 95% CI: 1.02-1.20) as risk factors for 14-day thrombotic events, but FEIBA usage was not associated with an increased risk.

CONCLUSIONS

In this retrospective cohort study, the use of FEIBA (∼1,000 units, ∼13 units/kg) to control perioperative hemorrhage following LVAD implantation was not associated with increases in mortality or composite thrombotic outcome.

Extracorporeal Life Support for Cardiogenic Shock With Either a Percutaneous Ventricular Assist Device or an Intra-Aortic Balloon Pump

Extracorporeal life support (ECLS) can result in complications due to increased left ventricular (LV) afterload. The percutaneous ventricular assist device (PVAD) and intra-aortic balloon pump (IABP) are both considered to be effective means of LV unloading. This study describes the efficacy of LV unloading and related outcomes with PVAD or IABP during ECLS. From January 2010 to April 2018, all cardiogenic shock patients who underwent ECLS plus simultaneous PVAD or IABP were analyzed. Forty-nine patients received ECLS + PVAD, while 91 received ECLS + IABP. At 48 hours, mean pulmonary artery pressure was significantly reduced in both groups [34 mm Hg to 22, p < 0.01; 32 mm Hg to 21, p < 0.01; ECLS + PVAD and ECLS + IABP group, respectively]. The two groups had similar 30 day survival rates [19 patients (39%) vs. 35 (39%), p = 0.56]. The ECLS + PVAD group had higher incidences of bleeding at the insertion site [11 (22%) vs. 0, p < 0.01] and major hemolysis [9 (18%) vs. 0, p < 0.01]. Both groups had improvement in LV end-diastolic dimension (61 ± 12 mm to 54 ± 12, p = 0.03; 60 ± 12 mm to 47 ± 10, p < 0.01), and LV ejection fraction (16 ± 7% to 22 ± 10, p < 0.01; 22 ± 12% to 29 ± 15, p = 0.01). Both ECLS + PVAD and ECLS + IABP effectively reduced pulmonary artery pressure and improved LV function. Bleeding at the PVAD or IABP insertion site occurred more frequently in the ECLS + PVAD group than the ECLS + IABP group (p < 0.01). Nine patients (18%) in the ECLS + PVAD group experienced major hemolysis, while there was no hemolysis in the ECLS + IABP group (p < 0.01). Careful considerations are required before selecting an additional support to ECLS.

Novel Model to Predict Gastrointestinal Bleeding During Left Ventricular Assist Device Support

BACKGROUND

Gastrointestinal bleeding (GIB) is a leading cause of morbidity during continuous-flow left ventricular assist device (CF-LVAD) support. GIB risk assessment could have important implications for candidate selection, informed consent, and postimplant therapeutic strategies. The aim of the study is to derive and validate a predictive model of GIB in CF-LVAD patients.

METHODS AND RESULTS

CF-LVAD recipients at the Utah Transplantation Affiliated Hospitals program between 2004 and 2017 were included. GIB associated with a decrease in hemoglobin ≥2 g/dL was the primary end point. A weighted score comprising preimplant variables independently associated with GIB was derived and internally validated. A total of 351 patients (median age, 59 years; 82% male) were included. After a median of 196 days, GIB occurred in 120 (34%) patients. Independent predictors of GIB included age >54 years, history of previous bleeding, coronary artery disease, chronic kidney disease, severe right ventricular dysfunction, mean pulmonary artery pressure <18 mm Hg, and fasting glucose >107 mg/dL. A weighted score termed Utah bleeding risk score, effectively stratified patients based on their probability of GIB: low (0-1 points) 4.8%, intermediate (2-4) 39.8%, and high risk (5-9) 83.8%. Discrimination was good in the development sample (c-index: 0.83) and after internal bootstrap validation (c-index: 0.74).

CONCLUSIONS

The novel Utah bleeding risk score is a simple tool that can provide personalized GIB risk estimates in CF-LVAD patients. This scoring system may assist clinicians and investigators in designing tailored risk-based strategies aimed at reducing the burden posed by GIB in the individual CF-LVAD patient and healthcare systems.

Predicting Transfusions During Left Ventricular Assist Device Implant

Perioperative bleeding and transfusion cause morbidity and mortality in patients receiving left ventricular assist devices (LVADs). We assessed factors associated with transfusions within 30 days of durable LVAD implantation and the clinical outcomes associated with transfusions. A retrospective cohort study of patients undergoing initial durable LVAD implantation between 2014 and 2016 was performed. Rates of packed red blood cell (PRBC) or other blood product transfusions (platelets or fresh frozen plasma) were assessed. Ordinal multivariable regression analysis was performed to determine factors independently associated with transfusion. Analysis included 156 patients, mean age 54.6 years and 74.4% male, who received a mean of 11.7 units of PRBC and 10.0 units of other products within 30 days. Preimplant mechanical ventilation, dialysis, higher INR, previous sternotomy, higher model for end-stage liver disease score, and lower hemoglobin were associated with increased PRBC transfusion rates. Higher preoperative central venous pressure, mechanical ventilation, concomitant surgical procedures, previous sternotomy, and lower hemoglobin were associated with increased PRBC transfusion rates within 48 hours of implant (adjusted odds ratio [OR] 1.46, P = 0.013 per 5 mm Hg). There were no significant associations with ferritin (adjusted OR 1.00, P = 0.236) or transferrin saturation (adjusted OR 1.17, P = 0.068). Transfusions were associated with an increase in ventilation duration, intensive care unit length of stay, reoperation for bleeding, and all-cause mortality. In patients undergoing LVAD implantation, perioperative blood product exposure is common and associated with increased morbidity and mortality. Elevated central venous pressure and anemia are potentially modifiable factors associated with increased early PRBC transfusion rates.

Protected percutaneous coronary intervention with Impella CP in a patient with left main disease, severe left ventricular systolic dysfunction and established hemolysis

The use of the Impella device in patients with left ventricular (LV) systolic impairment undergoing left main (LM) percutaneous coronary intervention (PCI) has been growing exponentially. Data from observational studies and registries demonstrate that Impella-assisted high-risk PCI is safe and effective with a low rate of peri-procedural complications. Hemolysis is a potential limitation of virtually all mechanical circulatory support devices and a small incidence of hemolysis has been associated with Impella use. The safety and feasibility of Impella use in patients with established hemolysis has not been previously evaluated. We report the first described case in the literature of Impella-assisted left main stem (LMS) PCI in a patient with severe LV systolic dysfunction and autoimmune hemolytic anemia (AIHA). Despite the patient's high bleeding risk (active hemolysis, thrombocytopenia, impaired renal function, use of steroids), Impella placement and PCI were successfully performed without complication. Haemoglobin, bilirubin and lactate dehydrogenase (LDH) levels were closely monitored peri-procedurally with no evidence of exacerbation of the patient's hemolysis. We briefly discuss the mechanism of Impella-induced hemolysis and factors that can exacerbate hemolysis.

Association of Oxidative Stress and Platelet Receptor Glycoprotein GPIbα and GPVI Shedding During Nonsurgical Bleeding in Heart Failure Patients With Continuous-Flow Left Ventricular Assist Device Support

Nonsurgical bleeding (NSB) in heart failure (HF) patients with continuous-flow left ventricular assist device (CF-LVAD) support is the most common clinical complication. The aim of this study was to investigate the association between oxidative stress and platelet glycoproteins GPIbα and GPVI shedding on the incidence of NSB in CF-LVAD patients. Fifty-one HF patients undergoing CF-LVAD implantation and 11 healthy volunteers were recruited. Fourteen patients developed NSB (bleeder group) during 1 month follow-up duration, while others were considered nonbleeder group (n = 37). Several biomarkers of oxidative stress were quantified at baseline and weekly intervals in all patients. Surface expression and plasma elements of platelet receptor glycoproteins GPIbα and GPVI were measured. Oxidative stress biomarkers and platelet GPIbα and GPVI receptor-shedding (decreased surface expression and higher plasma levels) were found to be preexisting conditions in baseline samples of both groups of HF patients when compared with healthy volunteers. Significantly elevated oxidative stress biomarkers and platelet glycoprotein receptor shedding were observed in postimplant bleeder group temporarily when compared with nonbleeder group. Strong significant associations between biomarkers of oxidative stress and platelet glycoprotein receptor shedding were observed, suggesting a possible role of oxidative stress in platelet integrin shedding leading to NSB in CF-LVAD patients. Receiver operating characteristic analyses of GPIbα and GPVI indicated that the likelihood of NSB had a predictive power of bleeding complication in CF-LVAD patients. In conclusion, elevated oxidative stress may play a role in GPIbα and GPVI shedding in the event of NSB. Thus, oxidative stress and GPIbα and GPVI shedding may be used as potential biomarkers for bleeding risk stratification in those patients.

Risk Factors of Gastrointestinal Bleeding After Continuous Flow Left Ventricular Assist Device

This study aimed to compare von Willebrand factor (vWF) levels, ristocetin cofactor levels, platelet counts, aortic valve movements, and right heart failure (RHF) as risk factors of gastrointestinal (GI) bleeding in patients with continuous flow left ventricular assist device (cf-LVAD). In a single centre, 90 patients (mean age 52.0 ± 10.5 years), of which 59 were male and 31 were female, had cf-LVAD implantation from October 2010 to November 2012. Seventy-six (84.4%) patients had HeartWare (Medtronic, Mounds View, MN) and 14 (15.5%) had Heartmate II (Thoratec, Pleasanton, CA) implanted. vWF level, ristocetin cofactor level, and platelet count were measured before and after implantation to determine the presence of acquired von Willebrand Syndrome; aortic valve movement and postoperative RHF were evaluated to compare the difference in bleeding and nonbleeding patient groups. Fifteen patients (16.6%) suffered GI bleeding after cf-LVAD implantation. A statistically significant decrease was found in vWF and ristocetin cofactor levels from preoperative period to postoperative period in both bleeding and nonbleeding patient groups (p < 0.05). There was no significant difference in bleeding and nonbleeding groups regarding aortic valve movements (p ≥ 0.05). Postoperative RHF incidence was significantly high in the bleeding patient group compared with the nonbleeding group (p < 0.05). Therefore, depending on the findings of this study, acquired von Willebrand Syndrome was seen in all cf-LVAD patients, and postoperative RHF was an important risk factor for GI bleeding.

Acquired von Willebrand Syndrome Associated with Cardiovascular Diseases

The blood glycoprotein von Willebrand factor (VWF) plays an important role in hemostasis and thrombosis. VWF is produced and secreted as large multimers by endothelial cells and megakaryocytes. It is then cleaved in a sheer-stress dependent manner by a specific protease, ADAMTS13, into multimers consisting of 2–80 subunits. Among VWF multimers, high molecular weight (HMW) multimers play important roles in platelet aggregation. Therefore, their loss induces a hemostatic disorder known as von Willebrand disease (VWD) type 2A. Various cardiovascular diseases, such as aortic stenosis, hypertrophic obstructive cardiomyopathy (HOCM), and several congenital structural diseases, as well as mechanical circulatory support systems, generate excessive high shear stress in the bloodstream. These cause excessive cleavage of VWF multimers resulting in a loss of HMW multimers, known as acquired von Willebrand syndrome (AVWS), a hemostatic disorder similar to VWD type 2A. Bleeding often occurs in the gastrointestinal tract since a fragile angiodysplasia develops associated with these diseases. Radical treatment for AVWS is to remove the pathological high shear causing AVWS.

Role of imaging in diagnosis and management of left ventricular assist device complications

Heart failure is a clinical condition that is associated with significant morbidity and mortality. With the advent of left ventricular assist device (LVAD), an increasing number of patients have received an artificial heart both as a bridge-to-therapy and as a destination therapy. Clinical trials have shown clear survival benefits of LVAD implantation. However, the increased survival benefits and improved quality of life come at the expense of an increased complication rate. Common complications include perioperative bleeding, infection, device thrombosis, gastrointestinal bleeding, right heart failure, and aortic hemodynamic changes. The LVAD-associated complications have unique pathophysiology. Multiple imaging modalities can be employed to investigate the complications, including computed tomography (CT), positron emission tomography-computed tomography (PET-CT), catheter angiography and echocardiography. Imaging studies not only help ascertain diagnosis and evaluate the severity of disease, but also help direct relevant clinical management and predict prognosis. In this article, we aim to review the common LVAD complications, present the associated imaging features and discuss the role of imaging in their management.

Hospital Complications and Causes of 90-Day Readmissions After Implantation of Left Ventricular Assist Devices

Left ventricular assist devices (LVADs) have emerged as an attractive option in patients with advance heart failure. Nationwide readmission database 2013 to 2014 was utilized to identify LVAD recipients using ICD-9 procedure code 37.66. The primary outcome was 90-day readmission. Readmission causes were identified using ICD-9 codes in primary diagnosis field. The secondary outcomes were LVAD associated with hospital complications. Hierarchic 2-level logistic models were used to evaluate study outcomes. We identified 4,693 LVAD recipients (mean age 57 years, 76.2% males). Of which 53.9% were readmitted in first 90 days of discharge. Cardiac causes (33.3%), bleeding (21.3%), and infections (12.4%) were leading etiologies of 90-day readmissions. Significant predictors (odds ratio, 95% confidence interval, p value) of readmission were disposition to nursing facilities (1.33, 1.09 to 1.63, p = 0.01) and longer length of stay (1.01, 1.00 to 1.01, p <0.01). Although private insurance (0.75, 0.66 to 0.86, p <0.01), and self-pay (0.58, 0.42 to 0.81, p <0.01) predicted lower readmissions. Cardiac complications (36.3%), major bleeding (29.8%), and postoperative infections (10.4%) were most common LVAD-related complications. In conclusion, high early readmission rate was observed among LVAD recipients with Cardiac complications, bleeding complications, and infections were driving force for major complications and most of readmissions.

Tolerability and Biological Effects of Long-Acting Octreotide in Patients With Continuous Flow Left Ventricular Assist Devices

Patients with implanted continuous, nonpulsatile, left ventricular assist devices (LVADs) have increased the occurrence of gastrointestinal bleeding (GIB). Although the pathophysiology is multifactorial, there are few treatments beyond supportive care. Octreotide acetate is a somatostatin analog that reduces GIB in various patient populations. However, there are sparse case series that suggest octreotide acetate may reduce GIB in LVAD patients. This 10 patient, 28 week phase I study evaluated the safety and tolerability of octreotide acetate long-acting release (LAR) 20 mg depot injection every 4 weeks until week 16 after LVAD placement. Secondary aims were occurrence of GIB and measurement of vascular endothelial growth factor, fibrinogen, von Willebrand factor, and platelet aggregation across the study period. Ten patients were enrolled, and eight completed the study. The two study dropouts were not related to octreotide. None of the patients experienced side effects or safety concerns related to octreotide nor did GIB occur in the study population. Vascular endothelial growth factor levels were maintained in the reference range throughout the duration of the study. There did appear to be laboratory evidence of acquired von Willebrand syndrome, with mildly low platelet aggregation studies. In conclusion, octreotide acetate LAR 20 mg depot injection was safe and effective in this population.

Active Clearance of Chest Tubes Reduces Re-Exploration for Bleeding After Ventricular Assist Device Implantation

Chest tubes are utilized to evacuate shed blood after left ventricular assist device (LVAD) implantation, however, they can become clogged, leading to retained blood. We implemented a protocol for active tube clearance (ATC) of chest tubes to determine if this might reduce interventions for retained blood. A total of 252 patients underwent LVAD implantation. Seventy-seven patients had conventional chest tube drainage (group 1), whereas 175 patients had ATC (group 2). A univariate and multivariate analysis adjusting for the use of conventional sternotomy (CS) and minimally invasive left thoracotomy (MILT) was performed. Univariate analysis revealed a 65% reduction in re-exploration (43-15%, p < 0.001), and an 82% reduction in delayed sternal closure (DSC; 34-6%, p <0.001). In a sub-analysis of CS only, there continued to be statistically significant 53% reduction in re-exploration (45% vs. 21%, p = 0.0011), and a 77% reduction in DSC (35% vs. 8%, p < 0.001) in group 2. Using a logistic regression model adjusting for CS versus MILT, there was a significant reduction in re-exploration (odds ratio [OR] = 0.44 [confidence interval {CI} = 0.23-0.85], p = 0.014) and DSC (OR = 0.20 [CI = 0.08-0.46], p <0.001) in group 2. Actively maintaining chest tube patency after LVAD implantation significantly reduces re-exploration and DSC.

Associations of Preimplant Red Blood Cell Distribution Width with Clinical Outcomes Among Individuals with Left Ventricular Assist Devices

Left ventricular assist devices (LVADs) are increasingly used for end-stage heart failure. However, post-LVAD complications are potentially devastating and remain unpredictable. The red blood cell distribution width (RDW) is a predictor of adverse events in patients with heart failure but has not been studied in the LVAD population. We reviewed laboratory results and clinical outcomes for all continuous flow LVADs implanted from 2004 to June 2014 (N = 188). Cox proportional hazards models adjusted for demographic, cardiovascular, and laboratory variables were used to assess association of preimplant RDW tertiles with mortality, gastrointestinal bleed, infection, pump thrombosis, and stroke more than 1 year of follow-up. Compared with the lowest tertile (RDW < 15.7%), the higher two tertiles (RDW 15.7-18% and RDW >18.1%) had significantly higher risks of mortality (hazard ratio (HR) 6.95 [confidence interval: 2.67-18.10] and HR 4.61 [1.74-12.21], respectively) after full adjustment. Preimplant RDW was not statistically associated with our secondary outcomes. In conclusion, higher preimplant RDW is independently associated with an increased risk of postimplant mortality and infection. Future studies are needed to understand the prognostic ability of RDW and to understand the biologic mechanism underlying this association.

Utility and correlation of known anticoagulation parameters in the management of pediatric ventricular assist devices

AIM

To assess utility and correlation of known anticoagulation parameters in the management of pediatric ventricular assist device (VAD).

METHODS

Retrospective study of pediatric patients supported with a Berlin EXCOR VAD at a single pediatric tertiary care center during a single year.

RESULTS

We demonstrated associations between activated thromboplastin time (aPTT) and R-thromboelastography (R-TEG) values (rs = 0.65, P < 0.001) and between anti-Xa assay and R-TEG values (rs = 0.54, P < 0.001). The strongest correlation was seen between aPTT and anti-Xa assays (rs = 0.71, P < 0.001). There was also a statistically significant correlation between platelet counts and the maximum amplitude of TEG (rs = 0.71, P < 0.001). Importantly, there was no association between dose of unfractionated heparin and either measure of anticoagulation (aPTT, anti-Xa or R-TEG value).

CONCLUSION

This study suggests that while there is strong correlation between aPTT, anti-Xa assay and R-TEG values for patients requiring VAD support, there is a lack of relevant correlation between heparin dose and degree of effect. This raises concern as various guidelines continue to recommend using these parameters to titrate heparin therapy.

Pulmonary Valve Opening With Two Rotary Left Ventricular Assist Devices for Biventricular Support

Right ventricular failure is a common complication associated with rotary left ventricular assist device (LVAD) support. Currently, there is no clinically approved long-term rotary right ventricular assist device (RVAD). Instead, clinicians have implanted a second rotary LVAD as RVAD in biventricular support. To prevent pulmonary hypertension, the RVAD must be operated by either reducing pump speed or banding the outflow graft. These modes differ in hydraulic performance, which may affect the pulmonary valve opening (PVO) and subsequently cause fusion, valvular insufficiency, and thrombus formation. This study aimed to compare PVO with the RVAD operated at reduced speed or with a banded outflow graft. Baseline conditions of systemic normal, hypo, and hypertension with severe biventricular failure were simulated in a mock circulation loop. Biventricular support was provided with two rotary VentrAssist LVADs with cardiac output restored to 5 L/min in banded outflow and reduced speed conditions, and systemic and pulmonary vascular resistances (PVR) were manipulated to determine the range of conditions that allowed PVO without causing left ventricular suction. Finally, RVAD sine wave speed modulation (±550 rpm) strategies (co- and counter-pulsation) were implemented to observe the effect on PVO. For each condition, outflow banding had higher PVR (97 ± 20 dyne/s/cm⁵ higher) for when the pulmonary valve closed compared to reduced speed. In addition, counter-pulsation demonstrated greater PVO than co-pulsation and constant speed. For the purpose of reducing the risks of pulmonary valve insufficiency, fusion, and thrombotic event, this study recommends a RVAD with a steeper H-Q gradient by banding and further exploration of RVAD speed modulation.

Bleeding with the artificial heart: Gastrointestinal hemorrhage in CF-LVAD patients

Continuous-flow left ventricular assist devices (CF-LVADs) have significantly improved outcomes for patients with end-stage heart failure when used as a bridge to cardiac transplantation or, more recently, as destination therapy. However, its implantations carries a risk of complications including infection, device malfunction, arrhythmias, right ventricular failure, thromboembolic disease, postoperative and nonsurgical bleeding. A significant number of left ventricular assist devices (LVAD) recipients may experience recurrent gastrointestinal hemorrhage, mainly due to combination of antiplatelet and vitamin K antagonist therapy, activation of fibrinolytic pathway, acquired von Willebrand factor deficiency, and tendency to develop small intestinal angiodysplasias due to increased rotary speed of the pump. Gastrointestinal bleeding in LVAD patients remains a source of increased morbidity including the need for blood transfusions, extended hospital stays, multiple readmissions, and overall mortality. Management of gastrointestinal bleeding in LVAD patients involves multidisciplinary approach in stabilizing the patients, addressing risk factors and performing structured endoluminal evaluation with focus on upper gastrointestinal tract including jejunum to find and eradicate culprit lesion. Medical and procedural intervention is largely successful and universal bleeding cessation occurs in transplanted patients.

Angiodysplasia in von Willebrand Disease: Understanding the Clinical and Basic Science

Severe and intractable gastrointestinal bleeding caused by angiodysplasia is a debilitating problem for up to 20% of patients with von Willebrand disease (VWD). Currently, the lack of an optimal treatment for this recurrent problem presents an ongoing challenge for many physicians in their management of affected patients. Over the past few years, studies have pointed to a regulatory role for the hemostatic protein, von Willebrand factor (VWF), in angiogenesis, providing a novel target for the modulation of vessel development. This article will review the clinical implications and molecular pathology of angiodysplasia in VWD.

Perioperative onset of acquired von Willebrand syndrome: Comparison between HVAD, HeartMate II and on-pump coronary bypass surgery

OBJECTIVES

Acquired von Willebrand syndrome (AvWS) is associated with postoperative bleeding complications in patients with continuous flow left ventricular assist devices (CF-LVADs). The aim of this study is to analyze the perioperative vWF profile comparing an axial pump (HMII) to a centrifugal pump (HVAD) regarding the correlation between perioperative occurrence of AvWS, early- and late-postoperative bleeding events.

METHODS

From July 2013 until March 2015 blood samples of 33 patients (12 HMII/ 8 HVAD/ 13 controls) were prospectively collected at 12 different time points and analyzed for the vWF antigen (vWF:Ag), its activity (vWF:Ac) and the vWF:Ac/vWF:Ag-ratio (vWF:ratio). The follow up period for postoperative bleeding events was from July 2013 until July 2016.

RESULTS

Postoperatively, there was no difference in the vWF-profile between HVAD and HMII groups. However, a subgroup of patients already had significantly lower vWF:ratios preoperatively. Postoperatively, both CF-LVAD groups presented significantly lower vWF:ratios compared to the control group. Bleeding events per patient-year did not differ between the two groups (HMII vs. HVAD: 0.67 vs. 0.85, p = 0.685). We detected a correlation between vWF:ratio <0.7at LVAD-start (r = -0.583, p = 0.006) or at the end of surgery (r = -0.461, p = 0.035) and the occurrence of pericardial tamponade. In the control group, the drop in both vWF:Ag and vWF:Ac recovered immediately postoperatively above preoperative values.

CONCLUSION

A subgroup of patients with end-stage heart failure already suffers AvWS preoperatively. In both CF-LVAD groups, AvWS begins immediately after surgery. Intraoperative vWF:ratios <0.7 correlate with higher incidences of pericardial tamponade and re-operation. The presumably dilutive effect of the heart lung machine on vWF vanishes immediately at the end of surgery, possibly as part of an acute-phase response.

Gastrointestinal Bleeding During the Index Hospitalization for Mechanical Circulatory Support Devices Implantation, a Nationwide Perspective

BACKGROUND

Gastrointestinal bleeding (GIB) is a common adverse event after mechanical circulatory support device implantation. However, the majority of the reported data were obtained from small single-center studies. Our aim was to study the prevalence and predictors of GIB during the index hospitalization of mechanical circulatory support devices implantation using a nationwide database.

METHODS

Nationwide inpatient sample (2009-2011) was used to perform a retrospective cross-sectional study. Adult patients with discharge diagnosis codes of congestive heart failure and procedure codes of left-ventricular assist device (LVAD) or intra-aortic balloon pump (IABP) implantation or orthotopic heart transplant (OHT, reference group) were identified. Our outcome was GIB during the index hospitalization when the device was implanted. Predictors that achieved statistical significance on the univariate analysis were included in a multivariable logistic-regression analysis.

RESULTS

A total of 87,462 patients were included, 87 % of the patients received an IABP, 6 % received LVAD, and 5 % underwent OHT. Prevalence of GIB was 8, 5, and 3 % among those who had LVAD, IABP implantation, and OHT recipients, respectively (p < 0.001). Patients who underwent LVAD implantation had twofold increase in the prevalence of GIB (OR 2.1, 1.7-2.5, p < 0.001) when using IABP or OHT groups as a reference. This increase in the prevalence was not demonstrated among IABP recipients on a multivariate level.

CONCLUSION

Prevalence of GIB was higher among LVAD compared to OHT and IABP recipients and could occur as early as the index admission of the device implantation.

Effects of HeartWare ventricular assist device on the von Willebrand factor: results of an academic Belgian center

Background

Left Ventricular Assist Device (LVAD) is a promising therapy for patients with advanced heart failure (HF), but bleeding complications remain an important issue. Previous series show that acquired von Willebrand syndrome was present in up to 100 % of first generation LVAD recipients. We report the effects of new generation LVADs on vW factor (vWF) metabolism and activity in our center.

Methods

Fifteen LVAD recipients (HeartWare®, Framingham, MA, USA) were compared to 12 HF patients, matched for age and body mass index. vWF antigen and activity, as well as D-dimers, were measured on hemostasis analyzers. A vWF LVAD-induced alteration was evocated when the [vWF activity]/[vWF antigen] ratio was <0.6. ADAMTS13 and high molecular weight multimers of vWF were also assessed.

Results

LVAD recipients had similar levels of endothelial vWF production than the HF subjects (137 ± 14.5 vs. 147 ± 11.7 %; respectively, p = 0.611) but a decreased vWF activity (90 ± 11 vs. 132.6 ± 13 %; respectively, p = 0.017). [vWF activity]/[vWF antigen] ratio was 0.65 ± 0.02 in the LVAD recipients and 0.92 ± 0.06 in the subjects with HF (p = 0.001). ADAMTS13 activity was 80.3 ± 4.7 % in LVAD recipients and 96.2 ± 3.5 % in the HF patients (p = 0.016). LVAD patients disclosed markedly elevated D-dimers (3217.7 ± 735 vs. 680.6 ± 223.2 ng/mL FEU in the HF patients, p = 0.006). The LVAD patients experienced one major hemorrhagic event and one systemic thrombotic event during the median follow-up of 345 days.

Conclusions

LVAD recipients achieved a new hemostatic equilibrium characterized by infrequent major hemorrhagic and thrombotic events, despite a mildly impaired vWF function and a markedly enhanced thrombin formation.

Trial registration

ISRCTN39517567

Electronic supplementary material

The online version of this article (doi:10.1186/s12872-016-0334-z) contains supplementary material, which is available to authorized users.

Gastrointestinal Bleeding during Continuous-Flow Left Ventricular Assist Device Support is Associated with Lower Rates of Cardiac Transplantation

Gastrointestinal bleeding (GIB) remains a significant problem after continuous-flow left ventricular assist device (CF-LVAD) implantation. We hypothesized that the subsequent need for blood transfusions in patients with GIB may reduce rates of cardiac transplantation. We performed a retrospective review of 232 patients implanted with the HeartMate II (HM II) CF-LVAD from June 2005 through May 2013 at our center to determine risk factors for GIB and assess its effect on cardiac transplantation. Over a total LVAD follow-up time of 364 person-years, 62 GIB episodes occurred in 49 patients (27%), for an event rate of 0.45 gastrointestinal bleeds/patient-year of LVAD support. Women made up 15% of our cohort, yet contributed 29% of the GIB (p = 0.06). Survival at 6 month, 1 year, and 2 years was not statistically different in patients who developed GIB and those who did not (77% vs 78%, 74% vs 71%, and 61% vs 54%, respectively). In transplant-eligible patients, GIB was associated with a 27% lower rate of cardiac transplantation (rate ratio 0.73, p < 0.05). Although the mechanism behind this finding is unclear, GIB appears to be linked to higher transfusion rates, which may cause the development of subsequent allosensitization.

Visualization and analysis of biomaterial-centered thrombus formation within a defined crevice under flow

The blood flow pathway within a device, together with the biomaterial surfaces and status of the patient's blood, are well-recognized factors in the development of thrombotic deposition and subsequent embolization. Blood flow patterns are of particular concern for devices such as blood pumps (i.e. ventricular assist devices, VADs) where shearing forces can be high, volumes are relatively large, and the flow fields can be complex. However, few studies have examined the effect of geometric irregularities on thrombus formation on clinically relevant opaque materials under flow. The objective of this study was to quantify human platelet deposition onto Ti6Al4V alloys, as well as positive and negative control surfaces, in the region of defined crevices (∼50-150 μm in width) that might be encountered in many VADs or other cardiovascular devices. To achieve this, reconstituted fresh human blood with hemoglobin-depleted red blood cells (to achieve optical clarity while maintaining relevant rheology), long working optics, and a custom designed parallel plate flow chamber were employed. The results showed that the least amount of platelet deposition occurred in the largest crevice size examined, which was counterintuitive. The greatest levels of deposition occurred in the 90 μm and 53 μm crevices at the lower wall shear rate. The results suggest that while crevices may be unavoidable in device manufacturing, the crevice size might be tailored, depending on the flow conditions, to reduce the risk of thromboembolic events. Further, these data might be used to improve the accuracy of predictive models of thrombotic deposition in cardiovascular devices to help optimize the blood flow path and reduce device thrombogenicity.

Hemorrhoids screening and treatment prior to LVAD: is it a necessity?

Continuous-flow left ventricle assist devices (CF-LVADs) has become an essential modality in the management of stage D heart failure (HF) with significant improvement in survival and quality of life. Due to the durability of such devices and long term support complications such as bleeding and aortic insufficiency has emerged. Bleeding accounts for more than 20 % with the majority being from the gastrointestinal tract. The increase of bleeding tendency are mainly attributed to the loss of large von Willebrand's Factor (vWF) multimers due to shear stress with the chronic intake of anticoagulants. We are reporting two cases of patients with Stage D HF and history of hemorrhoids presenting for LVAD implantation. Many efforts that decrease bleeding related to CF-LVADs will be discussed with focus on hemorrhoids.

Haemolysis as a first sign of thromboembolic event and acute pump thrombosis in patients with the continuous-flow left ventricular assist device HeartMate II

Background

Despite advances in pump technology, thromboembolic events/acute pump thrombosis remain potentially life-threatening complications in patients with continuous-flow left ventricular assist devices (CF-LVAD). We sought to determine early signs of thromboembolic event/pump thrombosis in patients with CF-LVAD, which could lead to earlier intervention.

Methods

We analysed all HeartMate II recipients (n = 40) in our centre between December 2006 and July 2013. Thromboembolic event/pump thrombosis was defined as a transient ischaemic attack (TIA), ischaemic cerebrovascular accident (CVA), or pump thrombosis.

Results

During median LVAD support of 336 days [IQR: 182–808], 8 (20 %) patients developed a thromboembolic event/pump thrombosis (six TIA/CVA, two pump thromboses). At the time of the thromboembolic event/pump thrombosis, significantly higher pump power was seen compared with the no-thrombosis group (8.2 ± 3.0 vs. 6.4 ± 1.4 W, p = 0.02), as well as a trend towards a lower pulse index (4.1 ± 1.5 vs. 5.0 ± 1.0, p = 0.05) and a trend towards higher pump flow (5.7 ± 1.0 vs. 4.9 ± 1.9 L m, p = 0.06).

The thrombosis group had a more than fourfold higher lactate dehydrogenase (LDH) median 1548 [IQR: 754–2379] vs. 363 [IQR: 325–443] U/L, p = 0.0001). Bacterial (n = 4) or viral (n = 1) infection was present in 5 out of 8 patients. LDH > 735 U/L predicted thromboembolic events/pump thrombosis with a positive predictive value of 88 %.

Conclusions

In patients with a CF-LVAD (HeartMate II), thromboembolic events and/or pump thrombosis are associated with symptoms and signs of acute haemolysis as manifested by a high LDH, elevated pump power and decreased pulse index, especially in the context of an infection.

Anticoagulation management in mechanical circulatory support

Heart failure continues to be a worldwide epidemic, effecting over 23 million persons. Despite advances in medical therapy, the disease is progressive and a significant proportion of patients will need advanced heart replacement therapy. Continuous flow assist devices have become a standard approach for many patients both as a bridge to cardiac transplantation and as destination therapy (DT). However, device related complications such as bleeding and thrombosis continue to hinder further advancements of this technology. The field is rapidly advancing and efforts to reduce pump complications are directed towards improving hemocompatibility and maximizing blood flow without clinically significant hemolysis, areas of stasis or turbulent flow.

Pre-Operative Right Ventricular Dysfunction Is Associated With Gastrointestinal Bleeding in Patients Supported With Continuous-Flow Left Ventricular Assist Devices

OBJECTIVES

This study sought to determine whether severe right ventricular (RV) dysfunction in the pre-operative setting is associated with an increased risk of gastrointestinal bleeding (GIB) post-left ventricular assist device (LVAD).

BACKGROUND

GIB is a significant complication in patients supported with continuous-flow LVADs. The impact of RV dysfunction on the risk of GIB has not been investigated.

METHODS

We retrospectively identified 212 patients who survived index hospitalization after implantation of HeartMate II (Thoratec Corp., Pleasanton, California) or Heartware HVAD (HeartWare Corp., Framingham, Massachusetts) from June 2009 to April 2013. Patients with severe RV dysfunction on pre-LVAD echocardiogram (n = 37) were compared to patients without severe RV dysfunction (n = 175). The primary outcome was freedom from GIB.

RESULTS

The majority of patients were male (79%) with a median INTERMACS (Interagency Registry for Mechanically Assisted Circulatory Support) profile of 2 at LVAD implantation. There were no significant differences between cohorts with respect to demographics, comorbidities, device type, international normalization ratio, or aspirin strategy. During follow-up, 81 patients had GIB events: 23 of 37 (62%) in the severe RV dysfunction group versus 58 of 175 (33%) in the control group (p = 0.001). After adjustment for age and ischemic cardiomyopathy, severe RV dysfunction was associated with increased risk of GIB (hazard ratio: 1.799, 95% confidence interval: 1.089 to 2.973, p = 0.022).

CONCLUSIONS

In this single-center sample of patients supported with continuous-flow LVADs, severe RV dysfunction on pre-LVAD echocardiogram was associated with an increased risk of GIB. Further studies are needed to investigate possible mechanisms by which RV dysfunction increases the risk of GIB and to identify patient populations who may benefit from alterations in antithrombotic strategies.

Acquired von Willebrand factor deficiency caused by LVAD is ADAMTS-13 and platelet dependent

INTRODUCTION

The high shear rates induced by left ventricular assist devices cause acquired von Willebrand disease (aVWD). We hypothesised that an ex vivo model could be established to study whether mechanical shear stress alone causes aVWD or whether this process depends also on the VWF cleavage protein ADAMTS-13 and on platelets.

MATERIALS AND METHODS

Healthy volunteers and two patients with congenital ADAMTS-13 deficiency donated blood. In vitro closed extracorporeal circuits were established using medically approved left ventricular assist devices (LVAD). VWF multimers were quantified by gel electrophoresis; VWF antigen, ristocetin cofactor activity (VWF:RCo), ADAMTS-13 levels and platelet function were assessed.

RESULTS

The high shear stress in the extracorporeal circulation rapidly decreased VWF:RCo and thereby the VWF:RCo/VWF:Ag ratio by 47% (p<0.01) to pathologically low values. Concomitantly, high molecular weight multimers (HMWM) decreased: up to 14-15 mers were visible on the gels at baseline, which were reduced by a maximum of 6-7 mers, corresponding to an average 68% lower densitometry signal of HMWM (p<0.001). This was accompanied by marked reduction of aggregation by various agonists (p<0.005). In contrast, the two patients with congenital thrombocytopenic purpura with virtually complete deficiency of ADAMTS-13 activity had only a minimal or no decrease in multimers (p<0.005 vs. healthy controls). Similarly, no or minimal depletion of large multimers occurred, when normal plasma circulated without platelets.

CONCLUSION

An in vitro model for LVAD associated aVWD demonstrated that ADAMTS-13 and platelets contribute to the depletion of HMWM of VWF.

Unexpectedly High Prevalence of Acquired von Willebrand Syndrome in Patients with Severe Aortic Stenosis as Evaluated with a Novel Large Multimer Index

AIM

Severe gastrointestinal bleeding sometimes occurs in patients with aortic stenosis (AS), known as Heyde's syndrome. This syndrome is thought to be caused by acquired von Willebrand syndrome and is characterized by reduced large von Willebrand factor (vWF) multimers. However, the relationship between the severity of AS and loss of large vWF multimers is unclear.

METHODS

We examined 31 consecutive patients with severe AS. Quantitative evaluation for loss of large vWF multimers was performed using the conventional large vWF ratio and novel large vWF multimer index. This novel index was defined as the ratio of large multimers of patients to those of controls.

RESULTS

Loss of large vWF multimers, defined as the large vWF multimer index ＜80%, was detected in 21 patients (67.7%). The large vWF multimer ratio and the large vWF multimer index were inversely correlated with the peak aortic gradient (R = -0.58, p=0.0007, and R=-0.64, p＜0.0001, respectively). Anemia defined as hemoglobin ＜9.0 g/dl was observed in 12 patients (38.7%), who were regarded as Heyde's syndrome. Aortic valve replacement was performed in 7 of these patients, resulting in the improvement of anemia in all patients from a hemoglobin concentration of 7.5±1.0 g/dl preoperatively to 12.4±1.3 g/dl postoperatively (p＜0.0001).

CONCLUSIONS

Acquired von Willebrand syndrome may be a differential diagnosis in patients with AS with anemia. The prevalence of AS-associated acquired von Willebrand syndrome is higher than anticipated.

Mechanical Ventricular Assistance as Destination Therapy for End-Stage Heart Failure: Has it Become a First Line Therapy?

Patients with end-stage heart failure have poor quality of life and prognosis. Therapeutic options are scarce and are not available for all. Only few patients can be transplanted every year. Several medical and surgical strategies have shown limited ability to influence prognosis and quality of life. In the past years, technological progress has realized devices capable of providing appropriate hemodynamic stabilization and recovery of secondary organ failure. Recently, these devices have been assessed as definitive treatment for patients who do not qualify for transplantation or/and instead to transplantation (“destination therapy”). This indication is increasingly considered following the results of newest clinical study reporting long-term survival without device correlated adverse events using last generation devices, and acceptable quality of life. The current knowledge about destination therapy and some original data from the DAVID Study (an Italian multicenter prospective study designed to evaluate the patient’s survival rate and quality of life of patients implanted with these new devices as long-term support or destination therapy) are summarized herein.

Antithrombotic therapy for ventricular assist devices in children: do we really know what to do?

The use of ventricular assist devices (VADs) in children is increasing. Stroke and device-related thromboembolism remain the most feared complications associated with VAD therapy in children. The presence of a VAD causes dysregulation of hemostasis due to the presence of foreign materials and sheer forces intrinsic to the device resulting in hypercoagulability and potentially life-threatening thrombosis. The use of antithrombotic therapy in adults with VADs modulates this disruption in hemostasis, decreasing the risk of thrombosis. Yet, differences in hemostasis in children (developmental hemostasis) may result in variances in dysregulation by these devices and preclude the use of adult guidelines. Consequently, pediatric device studies must include safety and efficacy estimates of device-specific antithrombotic therapy guidelines. This review will discuss mechanisms of hemostatic dysregulation as it pertains to VADs, goals of VAD antithrombotic therapy for children and adults, and emerging antithrombotic strategies for VAD use in children.

Spontaneous hyphema and pupillary block in a patient with a left ventricular assist device

The left ventricular assist device (LVAD) has been a standard of care for the management of patients with advanced heart failure since the 1990s. An increased risk of spontaneous bleeding related to the device has been noted, ranging from minor epistaxis to major thoracic and mediastinal hemorrhages. To our knowledge, intraocular hemorrhage has not been previously reported. We report a 72-year-old patient with an LVAD who subsequently developed a spontaneous intraocular hemorrhage that manifested as hyphema, pupillary block, and acute intraocular pressure elevation.

Gastrointestinal bleed after left ventricular assist device implantation: incidence, management, and prevention

BACKGROUND

Continuous-flow left ventricular assist devices (CF-LVADs) have become the standard of care for patients with end-stage heart failure (HF). While these devices have improved durability compared to earlier generation left ventricular assist devices (LVADs), increased frequency in some complications has been seen, including gastrointestinal bleeding (GIB), pump thrombosis and hemolysis. We discuss the incidence, management and prevention of GIB after CF-LVAD implantation.

METHODS

We reviewed the current literature available on the incidence, management and prevention of GIB after CF-LVAD implantation with a focus on our experience at the University of Minnesota, with data on nearly 300 patients who received a CF-LVAD from 2005 to 2013.

RESULTS

The incidence of GIB after CF-LVAD varies between 18-40% in numerous studies. At the University of Minnesota, out of 233 patients who underwent HeartMate II (HMII) implantation between 2005-2013, 60 GIB episodes occurred in 51 patients (22%), with an event rate of 0.17 gastrointestinal bleeds/patient-year of support. The etiology of GIB appears to be multifactorial. The main factors which have been identified include the need for chronic anticoagulation, acquired von Willebrand syndrome, platelet dysfunction and increased incidence of arteriovenous malformations due to chronic low pulse pressure. When managing an LVAD patient with GIB, a multi-disciplinary approach is needed. The main goals of treatment are evaluating the location and severity of the bleed, holding anti-coagulants and resuscitation to maintain stable hemodynamics.

CONCLUSIONS

GIB is a complication with considerable morbidity. Future efforts to further understand the etiology of GIB and optimize anti-coagulation are needed to improve outcomes following CF-LVAD implantation.