Single-center experience of extended brain-death donor heart preservation with the organ care system.

BACKGROUND: The Organ Care System (OCS) (Transmedics, Andover, MA) reduces cold ischemic time of donor hearts by producing a normothermic beating state during ex vivo perfusion, enabling extended ex situ intervals, which potentially increases donor pool. We aimed to compare outcomes in utilization of OCS and conventional cold storage technique. METHODS: Consecutive heart transplants following brain death at our institution between May 2022 and July 2023 were analyzed. Recipients were divided into those receiving hearts preserved with OCS [N = 15] and those with conventional cold storage (Control, N = 27), with OCS utilization when anticipated ischemic time was more than 4 h. Pre-transplant characteristics and transplant outcomes were compared. RESULTS: OCS utilization allowed a significant increase in distance traveled for heart retrieval (OCS, 624 ± 269 vs. Control, 153 ± 128 miles, p < 0.001), with longer mean total preservation times (6.2 ± 1.1 vs 2.6 ± 0.6 h, p < 0.001). All but one patient displayed a general decrease or plateau in lactate throughout perfusion time by OCS. Both groups experienced similar rates of severe primary graft dysfunction (OCS, 6.7% [N = 1] vs. Control, 11.1% [N = 3], p = 0.63), with 100% in-hospital survival in the OCS group compared to 96.3% in the Control group (p = 0.34). Kaplan-Meier survival analysis showed that estimated one-year survival were comparable (OCS, 93.3 ± 6.4% vs. Control, 88.9 ± 6.0%, p = 0.61). CONCLUSION: With a mean preservation time of around 6 h and distance covered of over 600 miles, our results using OCS indicate a potential to safely increase the quantity and viability of accessible organs, thus broadening the donor pool without negatively affecting outcomes.

The Effect of Celecoxib on the Progression of Calcific Aortic Valve Disease-Protective or Pathogenic?

Calcific aortic valve disease (CAVD) is a debilitating condition for which there are limited therapeutic options aside from valve replacement. As such, it is crucial to explore alternative management strategies for CAVD. Non-steroidal anti-inflammatory drugs (NSAIDs), particularly celecoxib, have been the subject of debate in the literature regarding their potential impact on CAVD. We conducted an in-depth analysis of five studies exploring the effect of celecoxib on CAVD and found discrepancies in both methods and results. Our findings suggest that celecoxib may impact the development of this disease via multiple mechanisms, each of which may have different effects on its pathogenesis. We also discovered limited clinical research examining the connection between celecoxib use and CAVD in medical patients. As such, further studies are needed to clarify the role of celecoxib and other NSAIDs in CAVD progression in order to inform future treatment options and clarify their impact on the disease.

Ex Vivo Heart Perfusion for Cardiac Transplantation Allowing for Prolonged Perfusion Time and Extension of Distance Traveled for Procurement of Donor Hearts: An Initial Experience in the United States.

Scarcity of donor hearts continues to be a challenge for heart transplantation (HT). The recently Food and Drug Administration-approved Organ Care System (OCS; Heart, TransMedics) for ex vivo organ perfusion enables extension of ex situ intervals and thus may expand the donor pool. Because postapproval real-world outcomes of OCS in HT are lacking, we report our initial experience. Methods: We retrospectively reviewed consecutive patients who received HT at our institution in the post-Food and Drug Administration approval period from May 1 to October 15, 2022. Patients were divided into 2 groups: OCS versus conventional technique. Baseline characteristics and outcomes were compared. Results: A total of 21 patients received HT during this period, 8 using OCS and 13 conventional techniques. All hearts were from donation after brain death donors. The indication for OCS was an expected ischemic time of >4 h. Baseline characteristics in the 2 groups were comparable. The mean distance traveled for heart recovery was significantly higher in the OCS group (OCS, 845 ± 337, versus conventional, 186 ± 188 mi; P < 0.001), as was the mean total preservation time (6.5 ± 0.7 versus 2.5 ± 0.7 h; P < 0.001). The mean OCS time was 5.1 ± 0.7 h. In-hospital survival in the OCS group was 100% compared with 92.3% in the conventional group (P = 0.32). Primary graft dysfunction was similar in both groups (OCS 12.5% versus conventional 15.4%; P = 0.85). No patient in the OCS group required venoarterial extracorporeal membrane oxygenation support after transplant compared with 1 in the conventional group (0% versus 7.7%; P = 0.32). The mean intensive care unit length of stay after transplant was comparable. Conclusions: OCS allowed utilization of donors from extended distances that otherwise would not be considered because ischemic time would be prohibitive by conventional technique.

Cannulation-related adverse events of peripheral veno-arterial extracorporeal membrane oxygenation support in heart transplantation: Axillary versus femoral artery cannulation.

BACKGROUND: In heart transplantation (HT), peripheral veno-arterial extracorporeal membranous oxygenation (VA-ECMO) is utilized preoperatively as a direct bridge to HT or postoperatively for primary graft dysfunction (PGD). Little is known about wound complications of an arterial VA-ECMO cannulation site which can be fatal. METHODS: From 2009 to 2021, outcomes of 80 HT recipients who were supported with peripheral VA-ECMO either preoperatively or postoperatively were compared based on the site of arterial cannulation: axillary (AX: N = 49) versus femoral artery (FA: N = 31). RESULTS: Patients in the AX group were older (AX: 59 years vs. 52 years, p = .006), and less likely to have extracorporeal cardiopulmonary resuscitation (0% vs. 12.9%, p = .040). Survival to discharge (AX, 81.6% vs. FA. 90.3%, p = .460), incidence of stroke (10.2% vs. 6.5%, p = .863), VA-ECMO cannulation-related bleeding (6.1% vs. 12.9%, p = .522), and arm or limb ischemia (0% vs. 3.2%, p = .816) were comparable. ECMO cannulation-related wound complications were lower in the AX group (AX, 4.1% vs. FA, 45.2%, p < .001) including the wound infections (2.0% vs. 32.3%, p < .001). In FA group, all organisms were gram-negative species. In univariate logistic regression analysis, AX cannulation was associated with less ECMO cannulation-related wound complications (Odds ratio, .23, p < .001). There was no difference between cutdown and percutaneous FA insertion regarding cannulation-related complications. CONCLUSIONS: Given the lower rate of wound complications and comparable hospital outcomes with femoral cannulation, axillary VA-ECMO may be an excellent option in HT candidates or recipients when possible.

Full disclosure: Unraveling the mystery of a wide complex tachycardia.

Wide complex tachycardia is not uncommon in patients with underlying structural heart disease and reduced ejection fraction. It is important to make the correct diagnosis as it carries prognostic and clinical implications. We present a case of a challenging wide complex rhythm detected on remote telemetry monitoring. This case outlines the differential diagnosis of a wide complex tachycardia and the clues to making a diagnosis of artifact. It highlights the importance of correct diagnosis as an incorrect diagnosis may lead to inappropriate treatments and unnecessary investigations.

A Craniomaxillofacial Surgical Assistance Workstation for Enhanced Single-Stage Reconstruction Using Patient-Specific Implants.

BACKGROUND: Craniomaxillofacial reconstruction with patient-specific, customized craniofacial implants (CCIs) is ideal for skeletal defects involving areas of aesthetic concern-the non-weight-bearing facial skeleton, temporal skull, and/or frontal-forehead region. Results to date are superior to a variety of "off-the-shelf" materials, but require a protocol computed tomography scan and preexisting defect for computer-assisted design/computer-assisted manufacturing of the CCI. The authors developed a craniomaxillofacial surgical assistance workstation to address these challenges and intraoperatively guide CCI modification for an unknown defect size/shape. METHODS: First, the surgeon designed an oversized CCI based on his/her surgical plan. Intraoperatively, the surgeon resected the bone and digitized the resection using a navigation pointer. Next, a projector displayed the limits of the craniofacial bone defect onto the prefabricated, oversized CCI for the size modification process; the surgeon followed the projected trace to modify the implant. A cadaveric study compared the standard technique (n = 1) to the experimental technique (n = 5) using surgical time and implant fit. RESULTS: The technology reduced the time and effort needed to resize the oversized CCI by an order of magnitude as compared with the standard manual resizing process. Implant fit was consistently better for the computer-assisted case compared with the control by at least 30%, requiring only 5.17 minutes in the computer-assisted cases compared with 35 minutes for the control. CONCLUSION: This approach demonstrated improvement in surgical time and accuracy of CCI-based craniomaxillofacial reconstruction compared with previously reported methods. The craniomaxillofacial surgical assistance workstation will provide craniofacial surgeons a computer-assisted technology for effective and efficient single-stage reconstruction when exact craniofacial bone defect sizes are unknown.

Embedded clutter reduction and face detection algorithms for a visual prosthesis.

Retinal prosthetic devices can significantly and positively impact the ability of visually challenged individuals to live a more independent life. We describe a visual processing system which leverages image analysis techniques to produce visual patterns and allows the user to more effectively perceive their environment. These patterns are used to stimulate a retinal prosthesis to allow self guidance and a higher degree of autonomy for the affected individual. Specifically, we describe an image processing pipeline that allows for object and face localization in cluttered environments as well as various contrast enhancement strategies in the "implanted image." Finally, we describe a real-time implementation and deployment of this system on the Argus II platform. We believe that these advances can significantly improve the effectiveness of the next generation of retinal prostheses.

Computer-assisted single-stage cranioplasty.

Cranioplasty treats and repairs cranial defects with a custom craniofacial implant (CCI). Typically, surgeons know the defect size prior to surgery. Recent efforts consider single-stage cranioplasty-performing the bony resection and fixating the CCI in a single operation. This paper develops a computer-assisted technique to perform single-stage cranioplasty. Intraoperatively, the surgeon traces the bony resection. The outline of the bony cuts is projected on a preoperatively-designed CCI to guide the surgeon during the resizing. A cadaveric case study showed good fit with minimal gaps between the implant and remaining skull. Moreover, the procedure reduced the time to resize the implant by an order of magnitude compared to manual resizing without the use of the computer-assisted technique. This approach represents the next step in quickly, effectively, and robustly performing single-stage CCI to treat craniofacial defects.

Effects of tools inserted through snake-like surgical manipulators.

Snake-like manipulators with a large, open lumen can offer improved treatment alternatives for minimally-and less-invasive surgeries. In these procedures, surgeons use the manipulator to introduce and control flexible tools in the surgical environment. This paper describes a predictive algorithm for estimating manipulator configuration given tip position for nonconstant curvature, cable-driven manipulators using energy minimization. During experimental bending of the manipulator with and without a tool inserted in its lumen, images were recorded from an overhead camera in conjunction with actuation cable tension and length. To investigate the accuracy, the estimated manipulator configuration from the model and the ground-truth configuration measured from the image were compared. Additional analysis focused on the response differences for the manipulator with and without a tool inserted through the lumen. Results indicate that the energy minimization model predicts manipulator configuration with an error of 0.24 ± 0.22mm without tools in the lumen and 0.24 ± 0.19mm with tools in the lumen (no significant difference, p = 0.81). Moreover, tools did not introduce noticeable perturbations in the manipulator trajectory; however, there was an increase in requisite force required to reach a configuration. These results support the use of the proposed estimation method for calculating the shape of the manipulator with an tool inserted in its lumen when an accuracy range of at least 1mm is required.

Failure rate of the Riata lead under advisory: a report from the CHRS Device Committee.

BACKGROUND: A unique form of lead failure has been described in the Riata (8-F) and Riata ST (7-F) silicone defibrillation lead degradation of the outer insulation, resulting in the externalization of conductor cables. OBJECTIVE: To assess rates of lead revision due to lead failure in Riata leads affected by the Riata advisory. METHODS: Nineteen implantable cardioverter-defibrillator implant and follow-up centers were surveyed. RESULTS: As of March 1, 2012, there were 5043 known affected leads implanted in Canada. Data on 4358 (86.4%) leads were obtained; 65.3% of these were Riata (8-F) and 32.4% were Riata ST (7-F) leads. The median time from implant to last follow-up was 5 years. Electrical abnormalities were reported in 4.6% of the affected leads; 8.0% of these were found to have concomitant radiographic evidence of externalization. The rate of electrical failure was higher in the 8-F (5.2%) vs 7-F (3.3%) leads (P = .007). Oversensing with or without inappropriate shocks was reported in 39.8% of the leads with confirmed failure. Abnormally high or low impedance values (29.9%) and elevated pacing capture thresholds (43.8%) were frequently reported. One death (0.5%) attributed to lead failure was reported. Among the leads that were replaced, 21% were extracted. Two major complications (1.0%) were attributed to extraction of these leads. CONCLUSIONS: The overall rate of lead failure in the Riata (8-F) and Riata ST (7-F) leads is higher than previously reported by using passive surveillance data. The impact of recent advisories related to these leads is not yet apparent.

Multiscale modeling of double-helical DNA and RNA: a unification through Lie groups.

Several different mechanical models of double-helical nucleic-acid structures that have been presented in the literature are reviewed here together with a new analysis method that provides a reconciliation between these disparate models. In all cases, terminology and basic results from the theory of Lie groups are used to describe rigid-body motions in a coordinate-free way, and when necessary, coordinates are introduced in a way in which simple equations result. We consider double-helical DNAs and RNAs which, in their unstressed referential state, have backbones that are either straight, slightly precurved, or bent by the action of a protein or other bound molecule. At the coarsest level, we consider worm-like chains with anisotropic bending stiffness. Then, we show how bi-rod models converge to this for sufficiently long filament lengths. At a finer level, we examine elastic networks of rigid bases and show how these relate to the coarser models. Finally, we show how results from molecular dynamics simulation at full atomic resolution (which is the finest scale considered here) and AFM experimental measurements (which is at the coarsest scale) relate to these models.

Complications associated with revision of Sprint Fidelis leads: report from the Canadian Heart Rhythm Society Device Advisory Committee.

BACKGROUND: It has been observed that replacement of an implantable cardioverter-defibrillator generator in response to a device advisory may be associated with a substantial rate of complications, including death. The risk of lead revision in response to a lead advisory has not been determined previously. METHODS AND RESULTS: Twenty-five implantable cardioverter-defibrillator implantation and follow-up centers from the Canadian Heart Rhythm Society Device Advisory Committee were surveyed to assess complication rates as a result of lead revisions due to the Sprint Fidelis advisory issued in October 2007. As of June 1, 2009, there had been 310 lead failures found in 6237 Sprint Fidelis leads in Canada (4.97%) over a follow-up of 40 months. There were 469 leads to be revised, 66% for confirmed fracture. Of the patients who underwent revision, 95% had a new lead inserted, whereas 4% had a pace/sense lead added. The lead was removed in 248 cases (53%), by simple traction in 61% and by laser lead extraction in 33%. Complications were encountered in 14.5% of the lead revisions; 7.25% of these were major, whereas 7.25% were minor. There were 2 deaths (0.43%). The overall risk of complications (19.8%) was greater in those who underwent lead removal at the time of revision than in those whose leads were abandoned (8.6%; P=0.0008). CONCLUSIONS: The overall rate of major complications that arose from lead revision due to the Sprint Fidelis advisory was significant. This must be taken into account when lead revision is planned in those patients who have not yet demonstrated an abnormality in lead performance.

Formation of a national network for rapid response to device and lead advisories: The Canadian Heart Rhythm Society Device Advisory Committee.

The Canadian Heart Rhythm Society (CHRS) Device Advisory Committee was commissioned to respond to advisories regarding cardiac rhythm device and lead performance on behalf of the CHRS. In the event of an advisory, the Chair uses an e-mail network to disseminate advisory information to Committee members broadly representative of the Canadian device community. A consensus recommendation is prepared by the Committee and made available to all Canadian centres on the CHRS Web site after approval by the CHRS executive. This collaborative approach using an e-mail network has proven very efficient in providing a rapid national response to device advisories. The network is an ideal tool to collect specific data on implanted device system performance and allows for prompt reporting of clinically relevant data to front-line clinicians and patients.