Mitral Valve Regurgitation After Lung Transplantation: Aetiology, Management and Outcome.

BACKGROUND: Problematic mitral regurgitation (MR) may develop following lung transplantation (LTx). There is limited information on the management of MR in LTx patients, as such we sought to evaluate our centre's experience. METHODS: From 2000 to 2019, 1,054 patients underwent LTx at our centre (896 bilateral, 158 single). We identified patients in whom significant MR developed at any point post-LTx. The aetiology of MR, management and outcome were retrospectively analysed. RESULTS: Eight (8) patients developed severe MR post-LTx, six following bilateral LTx and two following single LTx. Lung transplantation indications included interstitial lung disease (n=5), chronic obstructive pulmonary disease (n=2) and pulmonary arterial hypertension (n=1). Severe MR occurred intraoperatively (n=1), postoperative day 1 (n=1) with the remaining six cases between 80 and 263 days post-LTx. The aetiology was noted to be due to severe left ventricular dysfunction following unmasking of a chronically pulmonary hypertension-related under-preloaded left ventricle in one case, and in the remaining seven patients causes included myxomatous degeneration, ischaemic MR, and functional MR due to annular dilatation. In the patient with intraoperative severe MR, the MR became mild with veno-arterial extracorporeal membrane oxygenation (VA-ECMO) and in the remaining seven patients a variety of procedures were used, including mitral valve repair, valve replacement and transcatheter edge-to-edge mitral valve repair. All patients survived the mitral procedure. Two (2) deaths occurred at 12.9 years (stroke) and 5 years (cancer) from mitral valve surgery. CONCLUSIONS: Development of significant mitral valve regurgitation is a rare but morbid complication after lung transplantation. This may represent the progressive natural history of pre-existing degenerative mitral valve disease and rarely, early after transplantation may be related to changes in ventricular geometry. Management of severe MR can follow the same management approach as in the non-transplant community, with the expectation of similarly good results.

Donor Lung Procurement by Surgical Fellow With an Expectation of High Rate of Lung Utilisation.

There is an ever increasing demand for donor lungs in patients waiting for transplantation. Lungs of many potential donors will be rejected if the standard criteria for donor assessment are followed. We have expanded our donor lung pool by accepting marginal donors and establishing a donation after circulatory death program. We have achieved comparable results using marginal donors and accepting donor lungs following donation after circulatory death. We present our assessment and technical guidelines on lung procurement taking into consideration an increasingly complex cohort of lung donors. These guidelines form the basis of the lung procurement training program involving surgical Fellows at the Alfred Hospital in Melbourne, Australia.

Extracorporeal Life Support Bridge to Ventricular Assist Device: The Double Bridge Strategy.

In patients requiring left ventricular assist device (LVAD) support, it can be difficult to ascertain suitability for long-term mechanical support with LVAD and eventual transplantation. LVAD implantation in a shocked patient is associated with increased morbidity and mortality. Interest is growing in the utilization of extracorporeal life support (ECLS) as a bridge-to-bridge support for these critically unwell patients. Here, we reviewed our experience with ECLS double bridging. We hypothesized that ECLS double bridging would stabilize end-organ dysfunction and reduce ventricular assist device (VAD) implant perioperative mortality. We conducted a retrospective review of prospectively collected data for 58 consecutive patients implanted with a continuous-flow LVAD between January 2010 and December 2013 at The Alfred Hospital, Melbourne, Victoria, Australia. Twenty-three patients required ECLS support pre-LVAD while 35 patients underwent LVAD implantation without an ECLS bridge. Preoperative morbidity in the ECLS bridge group was reflected by increased postoperative intensive care duration, blood loss, blood product use, and postoperative renal failure, but without negative impact upon survival when compared with the no ECLS group. ECLS stabilization improved end-organ function pre-VAD implant with significant improvements in hepatic and renal dysfunction. This series demonstrates that the use of ECLS bridge to VAD stabilizes end-organ dysfunction and reduces VAD implant perioperative mortality from that traditionally reported in these "crash and burn" patients.

Pericardial Synovial Sarcoma: A Rare Clinical Entity.

Synovial sarcoma is an extremely rare form of primary malignancy of the pericardium. We present a case of primary synovial sarcoma of the pericardium followed by a review of the literature.

Right ventricular reconstruction after resection of cardiac fibroma.

Cardiac fibromas are rare neoplasms of myocardial fibroblasts. We present a case of a right ventricular fibroma and review the surgical management of these neoplasms.

Procurement of lungs for transplantation following donation after circulatory death: the Alfred technique.

INTRODUCTION: Donation after circulatory death (DCD) is an evolving method for lung transplantation (LTx) with results comparable to donation after brain death (DBD). MATERIALS AND METHODS: DCD lung transplant program requires a systematic approach for an efficient utilization of hospital resources. The surgical techniques have been developed to minimize the ischemic time during lung procurement. We have presented our management protocol and the surgical techniques as used at the Alfred Hospital in Melbourne, Australia. RESULTS: We have transplanted 92 recipients with lungs procured from 91 donors over an 8 year period from May 2006 to July 2014. This accounted for an extra 19% lung transplant operations performed during this time period. Operative mortality was 1% and 8 year survival was 71% in DCD lung recipients. CONCLUSIONS: DCD lung transplantation provides an additional significant pool of lung donors with satisfactory short and long term outcomes.

Laminectomy retractor: a useful tool for redo sternotomy.

Sternal re-entry represents a critical step during redo cardiac surgery. We describe a simple method that relies on opening of the posterior table of the sternum with a laminectomy retractor after dividing the anterior table with an oscillating saw.

Phrenic nerve injury during cardiac surgery: mechanisms, management and prevention.

Phrenic nerve injury is a well-recognised complication of cardiac surgery that can lead to disabling effects from diaphragmatic dysfunction, especially in children and patients with a history of chronic obstructive airway disease. Various mechanisms of injury have been recognised including hypothermia, mechanical trauma and possibly ischaemia. A clear understanding of these mechanisms is important in order to modify surgical techniques to prevent this serious complication of cardiac surgery.

Heart-Lung Transplantation: Technical Modifications to Simplify the Procedure.

Heart-lung transplantation is a mature therapy but has perioperative complications, such as phrenic nerve dysfunction and mediastinal bleeding. We report our technical modifications to simplify the procedure.

Extracorporeal Membrane Oxygenation as a Bridge to Surgical Repair of Postinfarct Ventricular Septal Defect.

Postinfarct ventricular septal defect (PIVSD) is associated with high mortality and the management of these patients has been a challenge with little improvement in outcomes. We commenced a protocol of veno-arterial extracorporeal membrane oxygenation (VA ECMO) for those patients who present in cardiogenic shock with the aim to improve end-organ function before definitive surgical repair to reduce postoperative mortality. This study reviewed the results of this strategy. This was a single-center, retrospective review of all patients who were admitted to our institution with PIVSD in cardiogenic shock from September 2015 to November 2019. Clinical and investigative data were evaluated. Eight patients were referred with PIVSD during this period in cardiogenic shock. One patient had an anterior PIVSD and the other seven had inferior PIVSD. Six patients underwent surgical repair at a median (interquartile range, IQR) of 7 (5-8) days after initiation of VA ECMO. Two patients did not undergo surgical repair. Five patients survived after surgery and one patient died postoperatively due to multiorgan failure. Preoperative use of VA ECMO is a feasible strategy for PIVSD and may improve the results of repair.

Spontaneous Coronary Artery Dissection in an Orthotopic Heart Transplant Recipient.

We present the case of acute myocardial infarction secondary to spontaneous coronary artery dissection in a patient 2 weeks post orthotopic heart transplantation. (Level of Difficulty: Advanced.).

Surgical Management of Heart Failure.

Optimal management of heart failure is collaborative, with the involvement of specialist heart failure physicians, nurses, interventionalists, and surgeons. In addition to medical optimisation and cardiac resynchronisation therapy, surgery plays a valuable role in many patients. We herein study the evidence and the role of surgical intervention in functional mitral regurgitation, coronary revascularisation in ischaemic cardiomyopathy, and surgical ventricular reconstruction. Additionally, we describe techniques of temporary and durable mechanical circulatory support, with their relative advantages and disadvantages, and applications. Finally, we describe the history and nomenclature around heart transplants, their indications, techniques, present-day outcomes, complications, and new developments in the field.

The results of a single-center experience with HeartMate 3 in a biventricular configuration.

BACKGROUND: Right ventricular (RV) failure after left ventricular assist device (VAD) implantation is a difficult problem. One solution is the implantation of continuous-flow VADs in a biventricular configuration. Disappointing survival and a concerning incidence of right-sided pump thrombosis have been previously reported. METHODS: From May 2017 to April 2020, a total of 12 patients underwent implantation of HeartMate 3 (HM3) biventricular VADs (BiVADs) as a bridge to cardiac transplantation. The right-sided pump was implanted in the right atrium in all cases. Adverse events and patient outcomes were determined. RESULTS: Patients were male, and the mean age was 44 years. The etiology was dilated cardiomyopathy (6 patients), sarcoid heart disease (2 patients), ischemic cardiomyopathy (1 patient), anthracycline cardiomyopathy (1 patient), non-compaction cardiomyopathy (1 patient), and arrhythmogenic RV cardiomyopathy with biventricular involvement (1 patient). There was 1 death from multisystem failure. There were 3 episodes of right VAD thrombus (thrombosis or clot ingestion); 1 managed medically, 1 recognized intraoperatively treated with clot retrieval, and 1 requiring pump exchange. There were 3 driveline infections. At 18 months after the procedure, 5 patients (41.7%) had undergone cardiac transplantation, 5 patients (41.7%) were alive and on biventricular support, 1 patient had died (8.3%), and 1 patient had VAD explantation for myocardial recovery (8.3%). Actuarial survival at 18 months was 91.7%. CONCLUSIONS: In this small study, HM3 BiVAD in these critically ill patients was used with low mortality. This suggests that the timely deployment of biventricular support with HM3 can be associated with favorable outcomes.

Emergency department resuscitative thoracotomy at an adult major trauma centre: Outcomes following a training programme with standardised indications.

OBJECTIVE: The objective of this study was to report the procedural incidence and patient outcomes after the 2009 introduction of an institutional resuscitative thoracotomy (RT) programme. Emergency physicians, general surgeons and emergency nursing trauma team members were trained to perform RT on thoracic trauma patients with an unresponsive systolic blood pressure (SBP) <70 mmHg within 30 min of arrival, prior to cardiothoracic team back-up. METHODS: A retrospective cohort study was conducted on patients who underwent RT from 2009 to 2017. The primary outcome measures were the incidence of the procedure and patients' survival to hospital discharge. Variables associated with survival were assessed using univariable logistic regression analyses. RESULTS: There were 12 399 major trauma patients, including 7657 with major thoracic trauma and 315 presenting with SBP <70 mmHg. There were 32 RTs performed (incidence of 0.4%; 95% confidence interval [CI] 0.3-0.6) among patients with major thoracic trauma and 10.2% (99% CI 7.3-13.4) among patients with major thoracic trauma and SBP <70 mmHg. There were eight (25%; 95% CI 13.2-42.1) survivors to hospital discharge and no late mortality (mean follow-up 2.8 years). Survival was significantly associated with the procedure performed within 30 min of arrival (odds ratio 0.09; 95% CI 0.01-0.67) while mortality was associated with the procedure being performed in the setting of traumatic cardiac arrest (odds ratio 18.3; 95% CI 2.4-140.4). CONCLUSIONS: A formal training and credentialing programme was associated with a low incidence of the procedure, yet achieved a survival rate of 25%, which is comparable to other reported literature.

Characterization of infected, explanted ventricular assist device drivelines: The role of biofilms and microgaps in the driveline tunnel.

BACKGROUND: Driveline infections remain a major complication of ventricular assist device (VAD) implantation. This study aimed to characterize in vivo microbial biofilms associated with driveline infections and host tissue integration of implanted drivelines. METHODS: A total of 9 infected and 13 uninfected drivelines were obtained from patients with VAD undergoing heart transplantation in Australia between 2016 and 2018. Each driveline was sectioned into 11 pieces of 1.5 cm in length, and each section was examined by scanning electron microscopy (SEM) and viable counts for microbial biofilms. Microorganisms were cultured and identified. Host tissue integration of clinical drivelines was assessed with micro-computed tomography (CT) and SEM. An in vitro interstitial biofilm assay was used to simulate biofilm migration in the driveline tunnel, and time-lapse microscopy was performed. RESULTS: Of the 9 explanted, infected drivelines, all had organisms isolated from varying depths along the velour section of the drivelines, and all were consistent with the swab culture results of the clinically infected exit site. SEM and micro-CT suggested insufficient tissue integration throughout the driveline velour, with microgaps observed. Clinical biofilms presented as microcolonies within the driveline tunnel, with human tissue as the sub-stratum, and were resistant to anti-microbial treatment. Biofilm migration mediated by a dispersal-seeding mechanism was observed. CONCLUSIONS: This study of explanted infected drivelines showed extensive anti-microbial-resistant biofilms along the velour, associated with microgaps between the driveline and the surrounding tissue. These data support the enhancement of tissue integration into the velour as a potential preventive strategy against driveline infections by preventing biofilm migration that may use microgaps as mediators.

A donor PaO2/FiO2 < 300 mm Hg does not determine graft function or survival after lung transplantation.

BACKGROUND: A donor arterial PO2/FiO2 (P/F ratio) of less than the 300 threshold would frequently result in either exclusion of the donor or placement of the lungs on ex vivo lung perfusion (EVLP). The aim was to investigate the veracity of the P/F ratio threshold of 300 for donor lung acceptability. METHODS: In 93 brain dead lung donors, arterial blood gases were drawn in the intensive care unit (ICU) just before procurement and each of the 4 donor pulmonary veins in the operating room (OR). No donor lungs were rejected for transplantation based on the last ICU or OR P/F ratio, and EVLP was not used. The recipients were followed up 6 and 12 months following transplantation. RESULTS: There were 93 recipients of bilateral lung transplantation. An arterial P/F ratio of < 300 was largely driven by a low P/F ratio in the lower lobes. There were no differences between the recipients receiving donor lungs where the ICU P/F ratio was < 300 compared with ≥ 300 in the time to extubation, grade of primary graft dysfunction, pulmonary function at 6 and 12 months, and 12-month survival. CONCLUSIONS: From this study:(1) If a donor P/F threshold of 300 was adhered to, 36% would have been rejected, and (2) The donor P/F ratio threshold of 300 is excessively conservative and results in the wastage of donor lungs and the application of unnecessary EVLP.

Prospective, randomized, controlled trial of polymer cable ties versus standard wire closure of midline sternotomy.

OBJECTIVE: Midline sternotomy remains the most common access incision for cardiac operations. Traditionally, the sternum is closed with stainless steel wires. Wires are well known to stretch and break, however, leading to pain, nonunion, and potential deep sternal wound infection. We hypothesized that biocompatible plastic cable ties would achieve a more rigid sternal fixation, reducing postoperative pain and analgesia requirements. METHODS: A prospective, randomized study compared the ZIPFIX (De Puy Synthes, West Chester, Pa) sternal closure system (n = 58) with standard stainless steel wires (n = 60). Primary outcomes were pain and analgesia requirements in the early postoperative period. Secondary outcome was sternal movement, as assessed by ultrasound at the postoperative follow-up visit. RESULTS: Groups were well matched in demographic and operative variables. There were no significant differences between groups in postoperative pain, analgesia, or early ventilatory requirements. Patients in the ZIPFIX group had significantly more movement in the sternum and manubrium on ultrasound at 4 weeks. CONCLUSIONS: ZIPFIX sternal cable ties provide reliable closure but no demonstrable benefit in this study in pain or analgesic requirements relative to standard wire closure after median sternotomy.

A Phase 1 Study of a Novel Bidirectional Perfusion Cannula in Patients Undergoing Femoral Cannulation for Cardiac Surgery.

OBJECTIVE: Leg ischemia is a serious complication of femoral artery cannulation. The primary aim of this study was to assess the safety and efficacy of a novel bidirectional femoral arterial cannula (Sorin Group USA, a wholly owned subsidiary of LivaNova PLC, Arvada, CO USA) that provides both antegrade and retrograde flow, in patients undergoing peripheral cannulation for cardiopulmonary bypass during cardiac surgery. METHODS: Patients undergoing routine cardiac surgery requiring femoral artery cannulation for cardiopulmonary bypass were identified preoperatively. Informed written consent was obtained in all cases. Bidirectional cannula insertion used either a surgical cut-down and wire through needle approach or a percutaneous technique. Flow in the superficial femoral artery was assessed using Doppler ultrasound after commencement of cardiopulmonary bypass. Lower limb perfusion was assessed using reflectance near-infrared spectroscopy to measure regional oxygen saturations in the cannulated limb during cardiopulmonary bypass. RESULTS: Fifteen patients (median age = 61.3 years, range = 26-79 years, 10 males, 5 females) underwent femoral arterial cannulation using the novel bidirectional femoral cannula between August 2016 and May 2017. Fourteen cannulae were inserted directly into the femoral artery via a surgical cut-down and wire through needle technique. One bidirectional cannula was inserted using a percutaneous insertion technique. Indications included minimally invasive mitral and aortic valve surgery, thoracic aortic aneurysm repair, and redo cardiac surgery. The median duration of cardiopulmonary bypass was 129 minutes (range = 53-228 minutes). The cannula was inserted and positioned without difficulty in 14 of 15 patients. Incorrect sizing and arterial spasm prevented correct cannula positioning in one patient. Antegrade flow in the superficial femoral artery was observed on Doppler ultrasound in 12 of 12 patients in which this was performed. Continuous stable distal perfusion was demonstrated in the cannulated limb in 14 of 15 patients. No procedural complications occurred in the immediate or convalescent postoperative period. CONCLUSIONS: This study demonstrates that in patients undergoing femoral arterial cannulation for cardiopulmonary bypass during cardiac surgery, the use of a novel bidirectional cannula is safe and easy to insert and provides stable distal perfusion of the cannulated limb. Use of the device should largely obviate the need to insert a separate downstream perfusion cannula or use other techniques to protect against lower limb ischemia. Further research on a larger scale and in different patient populations is now warranted.

Late presentation of right atrial thrombus following bilateral lung transplant.

A right atrial mass was incidentally detected in an immunosuppressed 49-year-old woman 5 years after successful bilateral lung transplantation. The mass was surgically excised and found to be an organized thrombus. There was no clear mechanism for the de-novo thrombus formation. The potential mechanisms include immunosuppression-related thrombogenicity, transient pericarditis, and stasis of blood from persisting pulmonary hypertension.