Five-year outcomes with alemtuzumab induction after lung transplantation

Efficacy of extracorporeal membrane oxygenation as a bridge to lung transplantation

BACKGROUND

Preoperative extracorporeal membrane oxygenation (ECMO) is a risk factor for poor outcome and currently considered a contraindication to lung transplantation. The lung allocation score system was introduced in May 2005 and prioritizes lung allocation to those with the greatest respiratory impairment. The purpose of this study is to determine whether ECMO as a bridge to lung transplantation is an acceptable option to support those in respiratory failure until donor lungs become available in the lung allocation score era.

METHOD

A retrospective review of 715 consecutive lung transplants performed between May 2005 and September 2011 was conducted using a prospectively collected institutional registry database. Twenty-four lung transplants (3.4%) were performed in the 31 patients with attempted pretransplant ECMO; 7 patients who received ECMO patients did not survive or were deemed unfit for transplantation. These patients were compared with a control group of 691 patients who did not receive pretransplant ECMO.

RESULTS

The duration of pretransplant ECMO was 171 ± 242 hours (median, 91 hours). Venovenous ECMO was used for respiratory failure in 15 patients, whereas venoarterial ECMO was used for circulatory collapse due to pulmonary hypertension in 9 patients. Patients in the retransplant ECMO group were younger (46 ± 15 years vs 57 ± 14 years, P < .01) compared with the control group, with no difference in recipient gender (male/female: 10/14 vs 380/311), donor age (33 ± 14 years vs 36 ± 15 years), or donor gender (male/female: 10/14 vs 352/339). Emphysema was less common (1, 4% vs 260, 38%, P < .01), and cystic fibrosis (5, 21% vs 72, 10%, P = .09), redo lung transplant (3, 13% vs 28, 4%, P = .08), and bronchiectasis (2, 8% vs 6, 1%, P = .03) were more common in the pretransplant ECMO group. Patients in the pretransplant ECMO group had a significantly higher lung allocation score (87 ± 9 vs 44 ± 15, P < .01). All patients in the pretransplant ECMO group underwent double lung transplants on pump (cardiopulmonary bypass/ECMO), and single lung transplants were performed in 171 patients (25%) and pump was used in 243 patients (35%) in the control group. The cardiopulmonary bypass time was longer in the pretransplant ECMO group (277 ± 69 minutes vs 225 ± 89 minutes, P = .02), with no difference in ischemic time (343 ± 93 minutes vs 330 ± 98 minutes, P = .54). Cadaveric lobar lung transplants were performed because of the urgency to overcome size mismatch with an oversized donor more frequently in 25% (n = 6, no mortality with the longest follow-up at 6 years) of patients in the pretransplant ECMO group versus 0.3% (n = 2) of patients in the control group (P < .01). Post-transplant ECMO was used for primary graft dysfunction in 13 patients (54%) in the pretransplant ECMO group and 41 patients (6%) in the control group (P < .01). The median hospital stay was 46 days in the pretransplant ECMO group versus 27 days in the control group (P = .16). The actuarial survivals after lung transplants at 1, 3, 6, 12, and 24 months were 96%, 88%, 83%, 74%, and 74%, respectively, in the pretransplant ECMO group, and 97%, 94%, 90%, 83%, and 74%, respectively, in the control group (P = .787).

CONCLUSIONS

Although the incidence of primary graft dysfunction requiring post-transplant ECMO is higher and the hospital stay is longer in patients receiving pretransplant ECMO, the graft survival is good (2-year survival, 74%). ECMO is efficacious as a bridge to lung transplantation with good post-lung transplant outcomes.

Epidemiology, clinical characteristics and outcomes of extensively drug-resistant Acinetobacter baumannii infections among solid organ transplant recipients

BACKGROUND

Extensively drug-resistant Acinetobacter baumannii (XDR-Ab) has emerged as a major nosocomial pathogen, but optimal treatment regimens are unknown. Although solid organ transplant (SOT) recipients are particularly susceptible to XDR-Ab infections, studies in this population are limited. Our objectives were to determine the epidemiology, clinical characteristics and outcomes of XDR-Ab infections among SOT patients.

METHODS

A retrospective study of SOT recipients at our center who were colonized or infected with XDR-Ab between November 2006 and December 2011 was conducted. Among infected patients, the primary outcome was survival at 28 days. Secondary outcomes included survival at 90 days and clinical success at 28 days, and XDR-Ab infection recurrence.

RESULTS

XDR-Ab was isolated from 69 SOT patients, of whom 41% (28) and 59% (41) were colonized and infected, respectively. Infections were significantly more common among cardiothoracic than abdominal transplant recipients (p=0.0004). Ninety-eight percent (40/41) of patients had respiratory tract infections, most commonly ventilator-associated pneumonia (VAP; 88% [36/41]). Survival rates at 28 and 90 days were 54% (22/41) and 46% (19/41), respectively. Treatment with a colistin-carbapenem regimen was an independent predictor of 28-day survival (p=0.01; odds ratio=7.88 [95% CI: 1.60-38.76]). Clinical success at 28 days was achieved in 49% (18/37) of patients who received antimicrobial therapy, but 44% (8/18) of successes were associated with infection recurrence within 3 months. Colistin resistance emerged in 18% (2/11) and 100% (3/3) of patients treated with colistin-carbapenem and colistin-tigecycline, respectively (p=0.03).

CONCLUSIONS

XDR-Ab causes VAP and other respiratory infections following SOT that are associated with significant recurrence and mortality rates. Cardiothoracic transplant recipients are at greatest risk. Results from this retrospective study suggest that colistin-carbapenem combinations may result in improved clinical responses and survival compared to other regimens and may also limit the emergence of colistin resistance.

Staphylococcus aureus infections in the early period after lung transplantation: epidemiology, risk factors, and outcomes

BACKGROUND

Staphylococcus aureus infections among lung transplant recipients are poorly studied.

METHODS

We conducted a 5-year retrospective study of the epidemiology, clinical manifestations, risk factors, and outcomes of patients infected with S aureus within the first 90 days after lung transplantation.

RESULTS

An S aureus infection developed in 109 of 596 lung transplant (18%) recipients. Methicillin-susceptible S aureus (MSSA; 62%) was more common than methicillin-resistant S aureus (MRSA; 38%); however, the proportion of infections caused by MRSA increased over time. Pneumonia (48%) was the most common infection, followed by tracheobronchitis (26%), bacteremia (12%), intrathoracic infections (7%), and skin/soft tissue infections (7%). Risk factors included mechanical ventilation for > 5 days and isolation of S aureus from recipients' sterility cultures. Patients with MRSA cultured from the nares or respiratory tract at the time of transplant were at an increased risk for MRSA infection (p < 0.0001 and p = 0.02, respectively). Infected patients required longer hospital and intensive care unit stays (p < 0.0001 for both), but the 30- and 90-day mortality rates from the onset of infection were only 7% and 12%, respectively. However, infected patients had higher rates of acute and chronic rejection at 1 (p = 0.048) and 3 years (p = 0.002), and higher rates of mortality at 1 (p = 0.058) and 3 years (p = 0.009).

CONCLUSIONS

S aureus infections within the first 90 days of lung transplant were associated with low short-term mortality but increased long-term rates of mortality and acute and chronic rejection. Future studies are needed to explore the utility of S aureus eradication strategies in reducing disease burden and improving outcomes.

Advances in immunosuppression after lung transplantation

Immunosuppression in transplantation has experienced changes in recent years as a result of the introduction of new drugs that act upon the different pathways of the host immune response with the purpose of securing more individualized immune suppression, with fewer side effects. Although following in the steps of other solid organ transplant modalities, lung transplantation, because of its special characteristics, has not yielded similar middle- and long-term results. Improved understanding of the underlying rejection mechanisms, the pharmacodynamic control of drugs, new administration routes designed to reduce the side effects, and new drug substances or immune modulating processes will all contribute to improve the expectations associated to lung transplantation in the near future.

Lung transplantation in patients with prior cardiothoracic surgical procedures

The full spectrum of prior cardiothoracic procedures in lung transplant candidates and the impact of prior procedures on outcomes after lung transplantation (LTx) remain unknown, though the impact is considered to be large. Patients transplanted at our institution from 2004 to 2009 were identified (n = 554) and divided into two groups: patients who had undergone cardiothoracic surgical (CTS) procedures prior to LTx (n = 238) and patients who had not (non-CTS: n = 316). Our primary endpoint was survival. Secondary endpoints included allograft function and the incidence of major complications including reexploration due to bleeding, prolonged ventilation, renal insufficiency and primary graft dysfunction. Long-term survival was not significantly different between the groups whereas postoperative bleeding, nerve injury, respiratory and renal complications were higher in the CTS group. Posttransplant peak FEV1 was lower in the CTS group (73.4% vs. 86.9%, p < 0.05). In multivariate analysis, performance of a chemical pleurodesis procedure and prolonged cardiopulmonary bypass were significantly associated with mortality (OR, 1.7; CI, 1.5-2.0; p < 0.005). Our results suggest that patients with LTx and prior CTS remain technically challenging and experience worse outcomes than patients without prior CTS. A surgical strategy to minimize cardiopulmonary bypass time is critical for these challenging LTx patients.