Driveline damage and repair in continuous-flow left ventricular assist devices: A systematic review

Transdermal wires for improved integration in vivo

Alternative engineering approaches have led the design of implants with controlled physical features to minimize adverse effects in biological tissues. Similar efforts have focused on optimizing the design features of percutaneous VAD drivelines with the aim to prevent infection, omitting however a thorough look on the implant-skin interactions that govern local tissue reactions. Here, we utilized an integrated approach for the biophysical modification of transdermal implants and their evaluation by chronic sheep implantation in comparison to the standard of care VAD drivelines. We developed a novel method for the transfer of breath topographical features on thin wires with modular size. We examined the impact of implant's diameter, surface topography, and chemistry on macroscopic, histological, and physical markers of inflammation, fibrosis, and mechanical adhesion. All implants demonstrated infection-free performance. The fibrotic response was enhanced by the increasing diameter of implants but not influenced by their surface properties. The implants of small diameter promoted mild inflammatory responses with improved mechanical adhesion and restricted epidermal downgrowth, in both silicone and polyurethane coated transdermal wires. On the contrary, the VAD drivelines with larger diameter triggered severe inflammatory reactions with frequent epidermal downgrowth. We validated these effects by quantifying the infiltration of macrophages and the level of vascularization in the fibrotic zone, highlighting the critical role of size reduction for the benign integration of transdermal implants with skin. This insight on how the biophysical properties of implants impact local tissue reactions could enable new solutions on the transdermal transmission of power, signal, and mass in a broad range of medical devices.

Left ventricular assist device exchange: a review of indications, operative procedure, and outcomes

The use of left ventricular assist devices (LVADs) is intended to treat patients with end-stage heart failure. Owing to technological advances, these devices are becoming more durable. However, LVADs may need to be exchanged when complications arise and heart transplantation is not possible. Indications for LVAD exchange (LVADE) include device thrombosis, device infections, and pump component failure. LVADE has historically been associated with a high risk of morbidity and mortality. In this review, we discuss the indications of LVADE, the decisional and technical aspects during surgery, and outcomes.

Left ventricular assist device exchange from HeartMate II to HeartMate 3 in an Asian patient-a case report and literature review

BACKGROUND

Pump exchange surgery of left ventricular assist device (LVAD) has been demonstrated in several studies; however, information for Asian patients was limited.

CASE PRESENTATION

A 63-year-old man underwent a pump upgrade from HeartMate II to HeartMate 3 for driveline damage through limited left anterior thoracotomy and lower partial sternotomy. He did not experience any hemodynamic adverse events or device malfunction during postoperative follow-ups of 12 months. We also reviewed all published cases with HeartMate II exchange to HeartMate 3.

CONCLUSIONS

The case demonstrated that it was safe and feasible to perform HMII LVAD exchange to HM3 through a limited approach for Asian patients.

Outcomes of modular cable exchange in HeartMate 3 patients versus conventional driveline repair in HeartMate II patients

BACKGROUND

Driveline (DL) damages are a common difficulty among ventricular assist devices (VAD). Repairing the electrical fibers inside the DL on a running pump is hazardous and requires technical expertise, which is not easily available on site. A new feature of the HeartMate3 (Abbott, U.S.A.) LVAD is a modular driveline that allows an easy exchange of the DL cord. In this report we analyze our experiences with this feature.

METHODS

We performed a retrospective analysis of 302 patients who underwent either HeartMate II or HeartMate 3 implantation between February 2004 and September 2021. Patients were screened for driveline faults and need for exchange or repair of driveline or VAD exchange. Documented were baseline characteristics, reasons for DL or VAD exchange, and complications. Follow-up was three months after the procedure.

RESULTS

We present a cohort of 302 patients who underwent either HMII (n = 107;35.4%) or HM 3 (n = 195; 64.5%) implantation. Out of those, 40 patients (40/302; 13.2%) required driveline repair (DLRe) or exchange (DLEx). Out of 107 HMII patients, 9 showed severe DL damages (9/107; 8.4%). Six patients (6/9; 66.6%) underwent DLRe, two patients (2/6; 33.3%) required VAD exchange after DLRe, one patient (1/2;50%) experienced emergency VAD exchange after pump stop. The DLRe procedure in the other four patients (4/6; 66.6%) was successful. Due to damage to the internal driveline two patients (2/9; 22.2%) underwent emergency device exchange and one patient (1/9;11.1%) was listed for transplantation. 31 out 195 HM3 patients underwent exchange of the modular DL. In none of the cases, damages of the internal fibers were the reasons for the exchange. In 100% of the cases, damages of the external coating were the reason for DL exchange. In none of the cases, complications occurred after the exchange procedure.

CONCLUSIONS

Driveline damages are a habitual, recurrent complication in VAD patients. The exchange of the modular driveline cable of the HM3 is feasible and safe compared to the conventional DL repair in HMII patients. Risky repair attempts and surgical LVAD exchange due to major damages of the electrical fibers can be avoided successfully by the new feature of HM3 driveline.