Driveline infections in left ventricular assist devices-Incidence, epidemiology, and staging proposal.

BACKGROUND: Driveline infections (DLI) are a serious complication in patients with left ventricular assist devices (LVAD). Apart from the differentiation between superficial and deep DLI, there is no consensus on the classification of the severity of DLI. Little is known about risk factors and typical bacteria causing DLI in centrifugal-flow LVADs. METHODS: In this single-center study with 245 patients, DLI were classified by their local appearance using a modification of a score suggested by the Sharp Memorial group. The driveline exit site was inspected routinely every 6 months. RESULTS: Severe DLI were detected in 34 patients (15%) after 6 months and in 24 patients (22%) after 24 months. The proportion of patients with DLI increased significantly during the follow-up (p = 0.0096). The most common bacteria in local smears were Corynebacterium, coagulase-negative Staphylococcus, and Staphylococcus aureus. Fifty-nine patients were hospitalized more than once for DLI. In these patients, S. aureus was the most common bacterium. It was also the most common bacterium in blood cultures. Higher BMI, no partnership, and a HeartMate 3 device were identified as risk factors for DLI in a multivariable cause-specific Cox regression. CONCLUSION: This study is a standardized analysis of DLI in a large cohort with centrifugal-flow LVADs.

Acute Outflow Graft Occlusion-A Novel Predictable Complication of Lysis Therapy for the Treatment of Left Ventricular Assist Device Intra-Pump Thrombosis.

Lysis therapy is an established treatment option for intra-pump thrombosis of left ventricular assist devices (LVADs). In clinical routine, we observed repeated cases of acute outflow graft occlusions (OGO) associated with lysis therapy with need for urgent intervention. The aim of this investigation was to gain understanding of this observation. We screened data of 962 HeartWare ventricular assist device (HVAD) patients. One hundred twenty (13.8%) had intra-pump thromboses; 58 were treated with recombinant tissue-type plasminogen activator (rtPA). Mean age was 53.0 ± 11.1 years; 84.9% were male. In 13 (24.5%) patients, OGO occurred following rtPA-lysis. These patients showed an increase in left ventricular function (18.45% ± 12.62% to 27.73% ± 10.57%; p = 0.056), more frequent 1:1 aortic valve opening (OGO+: +36.4%; OGO-: +7.4%; p = 0.026), a decrease in LVAD pulsatility within 12 months prior intra-pump thrombosis (OGO+: -0.8 L/min [interquartile range {IQR}, -1.4 to -0.4 L/min]; OGO-: -0.3 L/min [IQR, -0.9 to 0.1 L/min]; p = 0.038) and lower HVAD flows at admission (OGO+: 6.7 L/min [IQR, 6.1-7.4 L/min]; OGO-: 8.3 L/min [IQR, 6.9-9.3 L/min]; p = 0.013), indicating a subclinical OGO prior intra-pump thrombosis. There were no differences in implantation techniques, blood parameters, and lysis strategy. Subclinical OGO represented a major risk factor for acute OGO following rtPA lysis therapy. We here propose an algorithm for risk stratification and dealing with patients presenting this first-described complication. Further research is required to confirm our results and decipher the underlying pathomechanism. http://links.lww.com/ASAIO/B97.

Cardiac remodeling in patients with centrifugal left ventricular assist devices assessed by serial echocardiography.

AIM: The aim of the study was to characterize the remodeling process in a large cohort of patients supported with a centrifugal left ventricular assist device (cfLVAD) by standardized serial echocardiography. METHODS AND RESULTS: From 3/2018 all cfLVAD patients underwent transthoracic echocardiography at 6 and 12 months after implantation using a standardized protocol. A total of 512 echocardiograms were reviewed (216 preoperative, 156 at 6 months, 140 at 12 months). While on cfLVAD support, left ventricular (LV) diameter decreased (p < .001). LV ejection fraction (LVEF) and LV fractional area change improved (p < .001). Potential for cfLVAD explantation (as defined by an LVEF ≥45% and opening of the aortic valve [AV]) was seen in nine patients at 6 and 21 patients at 12 months. The tricuspid annular excursion decreased significantly, while the right ventricular fractional area change did not change. Tricuspid regurgitation (TR) and mitral regurgitation (MR) improved significantly during LVAD support. Opening of the AV was seen in >64% of the patients at 6 months and in 66% at 12 months. Moderate aortic regurgitation (AR) was rare with 3.8% at 6 months but increased with the duration of cfLVAD support (8.5% at 12 months). We found no significant difference in echocardiographic parameters between patients supported with a HeartWare HVAD™ or a HeartMate 3™ device. CONCLUSION: LVAD therapy can lead to reverse LV remodeling and improvement of MR and TR. However, right ventricular function does not improve and prevalence of AR progressively increases during mechanical support.

Interventional Procedures for Left Ventricular Assist Device-Associated Complications.

As patients on long-term left ventricular assist device (LVAD) face a substantial risk for open cardiac reoperation, interventional treatment approaches are becoming increasingly important in this population. We evaluated data of 871 patients who were on LVAD support between January 1, 2016 and December 1, 2020. Interventional treatments for LVAD-associated complications were performed in 76 patients. Seventeen patients underwent transcatheter aortic valve replacements (TAVR) and 61 patients underwent outflow graft interventions (OGI). TAVR improved symptoms in patients with severe symptomatic aortic regurgitation. Postinterventional complications included aggravation of preexisting right heart failure (RHF), third-degree atrioventricular block, and intrapump thrombosis (in 3 [16.7%], 2 [11.1%], and 1 [5.6%] patients, respectively). In outflow graft obstructions, OGI led to recovery of LVAD flow ( p < 0.001), unloading of the left ventricle ( p = 0.004), decrease of aortic valve opening time ( p = 0.010), and improvement of right heart function ( p < 0.001). Complications included bleeding, RHF, and others (in 9 [10.8%], 5 [6.0%], and 5 [6.0%] patients, respectively). Eight (9.6%) patients died within the hospital stay after OGI, including mortality secondary to prolonged cardiogenic shock. In conclusion, interventional procedures are a feasible and safe treatment modality for LVAD-associated complications.

Missing the blind spot in a HeartMate 3 LVAD outflow graft obstruction caused by fungal infection.

A patient was admitted in cardiogenic shock and a constant decrease of pump flow requiring combined inotropic support. To evaluate the cause, echocardiography and a ramp test were performed. The results suggested a LVAD related problem - particularly a suspected outflow graft obstruction. Wether CT scan nor angiography confirmed the assumption. However, a post-mortem LVAD examination revealed an outflow obstruction caused by a fungal thrombus formation invisible for standard imaging procedures.

Development of tricuspid regurgitation and right ventricular performance after implantation of centrifugal left ventricular assist devices.

BACKGROUND: Tricuspid regurgitation (TR) after left ventricular assist device (LVAD) implantation is associated with a poor prognosis. This study evaluates the development of TR and right ventricular (RV) performance after LVAD implantation. METHODS: Retrospective analysis of patients who underwent LVAD implantation between March 2018 and June 2019. Patients who underwent concomitant tricuspid valve surgery and patients with congenital heart disease were excluded. RESULTS: A total of 155 patients underwent LVAD implantation. Fourteen patients were excluded. Of the remaining patients, thirty-one died during the first six months, six were lost to follow-up and two underwent transplantation. 102 patients presented at 6.3 months (5.8 to 7.0). Patients were supported with HeartWare HVAD (74%) or HeartMate 3 (26%). 50.4% were rated as INTERMACS profile 1 or 2. At six months, systolic pulmonary artery pressure dropped from 36 to 21 mmHg (P<0.001). Tricuspid annular plane systolic excursion decreased from 17.3 to 14.3 mm (P<0.001), RV fractional area change did not change (P=0.839). Twenty-two patients (22%) presented with moderate-to-severe or severe (ms-s) TR pre-operatively. Of these, eighteen (81%) showed improvement to ≤ moderate TR. At follow-up twelve patients presented with ms-s TR. Of these, only four patients (33%) had been diagnosed with ms-s TR pre-operatively. There were no differences in pre-operative echocardiographic or clinical parameters between the twelve patients with ms-s late TR and the other ninety patients in the cohort. CONCLUSIONS: TR can show an impressive improvement with LVAD support. Longitudinal RV function decreases; this appears to be compensated by transverse shortening. Late TR can develop independently from pre-operative parameters including TR.

Eye Tracking Supported Human Factors Testing Improving Patient Training.

The handling of left ventricular assist devices (LVADs) can be challenging for patients and requires appropriate training. The devices' usability impacts patients' safety and quality of life. In this study, an eye tracking supported human factors testing was performed to reveal problems during use and test the trainings' effectiveness. In total 32 HeartWare HVAD patients (including 6 pre-VAD patients) and 3 technical experts as control group performed a battery change (BC) and a controller change (CC) as an everyday and emergency scenario on a training device. By tracking the patients' gaze point, task duration and pump-off time were evaluated. Patients with LVAD support ≥1 year showed significantly shorter BC task duration than patients with LVAD support <1 year (p = 0.008). In contrast their CC task duration (p = 0.002) and pump-off times (median = 12.35 s) were higher than for LVAD support patients <1 year (median = 5.3 s) with p = 0.001. The shorter BC task duration for patients with LVAD support ≥1 year indicate that with time patients establish routines and gain confidence using their device. The opposite effect was found for CC task duration and pump-off times. This implies the need for intermittent re-training of less frequent tasks to increase patients' safety.

Retrospective 1-year outcome follow-up in 200 patients supported with HeartMate 3 and HeartWare left ventricular assist devices in a single centre.

OBJECTIVES: Various trials have assessed the outcome and reliability of the HeartWare HVAD (HW) and HeartMate 3 (HM3) left ventricular assist devices. A direct comparison of clinical outcomes and of the complication profile of these 2 left ventricular assist devices is lacking. We present a retrospective analysis of patients supported with HM3 and HW as a left ventricular assist device. METHODS: Preoperative data, complications and outcomes including a 1-year follow-up of patients supported with the HM3 and HW in a single centre were retrospectively analysed. Both pumps were implanted on- or off-pump, employing standard and minimally invasive techniques. For logistic reasons, the 2 device types were implanted in an alternating manner, thereby reducing the systematic bias for pump selection. We considered this to be an appropriate approach, as no differences in respect of survival or the complication profile of the two device types have been demonstrated. Anticoagulation was similar in patients with both pumps according to our anticoagulation protocol, with a target international normalized ratio of 2.5-3.0, a home monitoring system and blood pressure management with a mean arterial target pressure of 70-80 mmHg. RESULTS: Between October 2015 and April 2017, 100 patients underwent implantation of the HW and 100 patients underwent implantation of the HM3. The median time on the device was 0.98 years (range 0-2.23 years). The median age was 58.5 (51-65) versus 57 (49-64) years (P = 0.456); the number of male patients was 87 versus 88 (P = 0.831). Of the HW patients, 73% were rated as having an INTERMACS level I or II, compared to 57% of the HM3 patients (P = 0.018). There were no further differences in preoperative data. A total of 14 patients had pre-, intra- or post-pump blood flow obstruction in the HW group versus 4 in the HM3 group [hazard ratio (HR) 2.5 (0.7-8.8), P = 0.103]. There were no differences regarding gastrointestinal bleeding [HR 1.25 (0.56-2.64), P = 0.624] or driveline infection (0.68 vs 0.8 events per patient-year, P = 0.0789). The incidence of ischaemic stroke was similar in both groups [HR 0.72 (0.25-2.09), P = 0.550]. Cerebral bleeding was more frequent in patients supported with HW [HR 6.79 (1.43-32.20), P = 0.016]. The incidence of cerebrovascular accidents, on the other hand, was similar in both groups [HR 1.85 (0.83-4.19), P = 0.13]. The incidence of haemocompatibility-related adverse events, however, was significantly higher in the HW group (113 points corresponding to 1.28 events per patient-year versus 69 points corresponding to 0.7 events per patient-year, P < 0.001). The 1-year survival was similar in both groups [62.2%, 95% confidence interval (CI) (0.53-0.73) vs 66.7%, 95% CI (0.58­0.767) [corrected]. CONCLUSIONS: Our data show that the complication profile differs between the 2 pumps, but that early survival is comparable.