Tanveer Butt

The effect of ex vivo lung perfusion on microbial load in human donor lungs

BACKGROUND Ex vivo lung perfusion (EVLP) has emerged as a technique to potentially recondition unusable donor lungs for transplantation. Beneficial effects of EVLP on physiologic function have been reported, but little is known about the effect of normothermic perfusion on the infectious burden of the donor lung. In this study, we investigated the effect of EVLP on the microbial load of human donor lungs. METHODS Lungs from 18 human donors considered unusable for transplantation underwent EVLP with a perfusate containing high-dose, empirical, broad-spectrum anti-microbial agents. Quantitative cultures of bacteria and fungi were performed on bronchoalveolar lavage fluid from the donor lung before and after 3 to 6 hours of perfusion. The identification of any organisms and changes in number of colony forming units before and after EVLP were assessed and anti-microbial susceptibilities identified. RESULTS Thirteen out of 18 lungs had positive cultures, with bacterial loads significantly decreasing after EVLP. Yeast loads increased when no anti-fungal treatment was given, but were reduced when prophylactic anti-fungal treatment was added to the circuit. Six lungs were ultimately transplanted into patients, all of whom survived to hospital discharge. There was 1 death at 11 months. CONCLUSIONS Our study shows that EVLP with high-dose, empirical anti-microbial agents in the perfusate is associated with an effective reduction in the microbial burden of the donor lung, a benefit that has not previously been demonstrated.

Management issues during HeartWare left ventricular assist device implantation and the role of transesophageal echocardiography

Left ventricular assist devices (LVAD) are increasingly used for mechanical circulatory support of patients with severe heart failure, primarily as a bridge to heart transplantation. Transesophageal echocardiography (TEE) plays a major role in the clinical decision making during insertion of the devices and in the post-operative management of these patients. The detection of structural and device-related mechanical abnormalities is critical for optimal functioning of assist device. In this review article, we describe the usefulness of TEE for optimal perioperative management of patients presenting for HeartWare LVAD insertion.

Vascular anastomotic complications in lung transplantation: a single institution's experience

OBJECTIVES Lung transplant recipients were reviewed to compare our early and current experience of vascular complications. Since 1995, we have had a policy of early identification and intervention. METHODS We undertook a retrospective review of all adult lung transplants performed at our centre. Patients with pulmonary vascular complications before and after 1995 were identified and reviewed to determine changes in management and outcome. RESULTS We identified a total of 13 patients with either pulmonary artery or venous obstruction out of a total of 720 adult lung transplants (1.8%). There were 9 females and 4 males with an age range of 25-64 years. Complications were more common in patients with fibrotic lung disease and involved 15 vascular anastomoses, most commonly the pulmonary arterial anastomosis. Prior to 1995, 5 cases were identified, all postoperatively. In this group, the mean time for identification of the complication was 9.4 (range 4-14) days. Only 1 patient survived to discharge. After 1995, vascular complications were identified intraoperatively in 4 cases and corrected immediately. Four cases were identified postoperatively (at <1-17 days) by a computed tomography pulmonary angiogram. Three were treated surgically within 24 h of diagnosis (using cardiopulmonary bypass with cold preservation). One patient was managed conservatively. Among patients identified after 1995, 5 survived to discharge. CONCLUSIONS Though rare, pulmonary vascular complications after lung transplantation carry high mortality. In our opinion, early identification and intervention improves outcome. Intraoperative assessment by pressure gradient measurement and transoesophageal echocardiography is recommended. Despite this, mortality remains high and prevention is better than cure.

An alternative approach to explantation and exchange of the HeartWare left ventricular assist device

OBJECTIVES Left ventricular assist device (LVAD) explantation and exchange is a relatively infrequent but potentially complex procedure. Patients requiring such procedures have multisystem suboptimal physiological reserve due to end-stage heart failure and are prone to complications. Less-invasive procedures are believed to facilitate postoperative recovery and early mobilization. We describe an alternative approach to explantation and exchange of the HeartWare LVAD through left thoracotomy. METHODS Six patients (M = 4, F = 2, mean age = 49.16 years) underwent device explant/exchange or initial implant (explant = 2, exchange = 3, initial implant = 1) through left thoracotomy utilizing cardiopulmonary bypass and induced ventricular fibrillation (VF). The mean bypass time and mean VF arrest time were 82 and 3 min, respectively. A new outflow graft was anastomosed to the previous outflow graft in 3 cases of device exchange and to the descending aorta in 1 case of initial implant. RESULTS One patient died in the intensive care unit due to unrelated causes (gram-negative sepsis) after device exchange. All others were discharged alive and currently remain on follow-up. The mean length of hospital stay was 40.66 days. CONCLUSIONS On-pump approach through single thoracotomy incision is safe and equally suitable for device explant, exchange and initial implant. However, structural heart defects requiring surgical correction and the requirement of simultaneous right ventricular assist device are the limitations of this approach.

Four-year outcomes with third-generation centrifugal left ventricular assist devices in an era of restricted transplantation

OBJECTIVES Third-generation ventricular assist devices (VADs) are associated with improved outcomes, though in recent clinical trials bridge-to-transplant (BTT) rates are ∼30% at 6 months, so that transplantation can be used as a ‘bail out’ for serious complications. In the UK, there was a significant reduction in heart transplantation rates over the last decade, so that transplantation from VADs is much less frequent. The objective of this study was to determine outcomes and their predictors in this situation of low BTT rates, and as patients were exposed to long-term support, the incidence and outcomes of VAD thrombosis. METHODS We analysed outcomes for 102 consecutive patients between 2009 and 2013 (mean age 47 ± 13; VentrAssist n = 6 and HeartWare n = 96). The median duration of support was 462 ± 426 days. RESULTS Survival rates on the device were 75 and 66% at 1 and 2 years, respectively. Older age and more acute INTERMACS groups were significantly related to reduced survival within the first 90 days (P = 0.030 and 0.010, respectively). Poor preoperative right ventricular (RV) function had a negative effect on survival after 1 year (P = 0.009), though not earlier. VAD thrombosis (n = 24 HeartWare and n = 1 VentrAssist) occurred at 0.18 events per patient-year for HeartWare and 0.07 for VentrAssist devices at a median time of onset at 404 ± 281 days. There was no significant effect of VAD thrombosis on survival. Only 14 of 102 patients were transplanted at a median of 334 ± 347 days, and only 3 were transplanted within the first 6 months. CONCLUSIONS Third-generation left ventricular assist device implants with a low rate of transplantation have similar survival to destination therapy, and are susceptible to long-term complications of VAD thrombosis and right heart failure.

Pregnancy in cardiac transplant recipients.

Successful pregnancy following cardiac transplantation has been described, although outcome data from individual centers are relatively sparse. We investigated maternal and fetal outcomes including change in left ventricular (LV) function and calcineurin inhibitor (CNI) dose in women who became pregnant from our institution.

Development of de novo aortic valve incompetence in patients with the continuous-flow HeartWare ventricular assist device.

BACKGROUND In this study we investigated the development of aortic incompetence (AI) and change in aortic root and left ventricular dimensions after implantation of the continuous-flow HeartWare ventricular assist device (HVAD) in our adult patient cohort. METHODS A retrospective analysis of serial echocardiograms was performed on patients implanted with an HVAD between July 2009 and July 2013. Data from echocardiograms performed before and at 1 and 2 years (±3 months) were analyzed. Patients with native aortic valves (AoVs) with no previous intervention and HVAD in situ for ≥6 months were included. RESULTS A total of 73 HVADs in 71 patients with a mean duration of support of 624 ± 359 days were included in our study. One patient developed moderate AI at 1 year (1.9%). Mild or greater AI was more likely in those with a closed or intermittently opening AoV at 1 year (p = 0.005). Aortic annulus dimensions increased significantly at 1 and 2 years, regardless of extent of AI. At 2 years, in those with mild or worse AI, the sinuses of Valsalva were also larger (p = 0.002). Left ventricular end-diastolic dimension (LVEDD) was significantly reduced in those with no or trace AI at 1 and 2 years (p = 0.012 and p = 0.008, respectively), but remained unchanged in those with AI at both time-points. CONCLUSIONS The development of more than mild AI is rare in HVAD patients at our center. When encountered, it is more common with a closed AoV. Dilation of the aortic annulus, and root dilation in those with mild or more AI, is seen with HVAD support over time.

Profiling inflammation and tissue injury markers in perfusate and bronchoalveolar lavage fluid during human ex vivo lung perfusion

Abstract OBJECTIVES: Availability of donor lungs suitable for transplant falls short of current demand and contributes to waiting list mortality. Ex vivo lung perfusion (EVLP) offers the opportunity to objectively assess and recondition organs unsuitable for immediate transplant. Identifying robust biomarkers that can stratify donor lungs during EVLP to use or non-use or for specific interventions could further improve its clinical impact. METHODS: In this pilot study, 16 consecutive donor lungs unsuitable for immediate transplant were assessed by EVLP. Key inflammatory mediators and tissue injury markers were measured in serial perfusate samples collected hourly and in bronchoalveolar lavage fluid (BALF) collected before and after EVLP. Levels were compared between donor lungs that met criteria for transplant and those that did not. RESULTS: Seven of the 16 donor lungs (44%) improved during EVLP and were transplanted with uniformly good outcomes. Tissue and vascular injury markers lactate dehydrogenase, HMGB-1 and Syndecan-1 were significantly lower in perfusate from transplanted lungs. A model combining IL-1β and IL-8 concentrations in perfusate could predict final EVLP outcome after 2 h assessment. In addition, perfusate IL-1β concentrations showed an inverse correlation to recipient oxygenation 24 h post-transplant. CONCLUSIONS: This study confirms the feasibility of using inflammation and tissue injury markers in perfusate and BALF to identify donor lungs most likely to improve for successful transplant during clinical EVLP. These results support examining this issue in a larger study.

Invasive biopsy is effective and useful after lung transplant

BACKGROUND Transbronchial biopsy (TBB) is widely used after lung transplant but may not be diagnostic. Our group has used invasive approaches, open lung biopsy (OLB) or video-assisted thoracoscopy (VAT), to establish a definitive diagnosis in unexplained clinical deterioration. We sought to demonstrate the risks and benefits of this approach. METHODS A retrospective review was made of the case notes of the patients undergoing OLB or VAT during a 12-year period from August 1996. RESULTS During a 12-year period in 442 recipients, there were 51 invasive biopsies in 45 patients (6 had 2 procedures), of which 41 (80%) were OLB and 10 (20%) were VAT. Time of biopsy ranged from 7 days to 11 years after transplant. Thirty-seven (73%) took place in the first year, including 12 (24%) within the first 30 days. Nine patients died within 30 days of biopsy; 7 of them were already ventilated. Overall, biopsy provided a new unsuspected diagnosis in 37% of patients and confirmed the diagnostic suspicion in 47%. In only 16% of patients did it fail to provide a result that was clinically useful. The results of 29 (57%) biopsies led to a change in treatment. Sixty-three percent of new diagnoses and 71% where clinical suspicion was confirmed resulted in a treatment change. In all but 2 cases, a change was made to medication. CONCLUSIONS In this large series of invasive biopsies, there was a high rate of useful results, with a frequent change in treatment. Invasive biopsies are a safe intervention in ambulatory patients.

Morgagni Hernia Presenting With Bowel Obstruction in a Lung Transplant Recipient: Case Report

Morgagni hernias are uncommon congenital diaphragmatic deficiencies that may remain asymptomatic till adulthood. We report a case of Morgagni hernia presenting with subacute bowel obstruction in a bilateral lung transplant recipient. This diaphragmatic deficiency was not evident during bilateral lung transplantation surgery via clamshell incision. To our knowledge this is the first report of a congenital defect evident after lung transplantation.