Timing of heparin and thrombus formation in donor lungs after cardiac death.

BACKGROUND: Heparin is routinely administered to brain-dead donors before cardiac arrest, although it is not universally allowed for donation after cardiac death (DCD) donors due to concerns that death may be hastened. The lack of heparin may lead to thrombosis and compromised graft function. We evaluated the impact of timing of heparin administration and thrombi formation in a DCD pig model. METHODS: Eight domestic adult pigs were administered systemic heparin (30,000 IU): four prior to cardiac arrest through intravenous injection (prearrest heparin) and four after cardiac arrest via injection into the right atrium followed by open cardiac massage (postarrest heparin). Pigs were euthanized with potassium chloride and a minimum of 5 minutes of cardiac silence allowed before organ procurement. Lungs were flushed with antegrade and retrograde Perfadex, and pulmonary preservation solution effluent was evaluated for gross thrombi. Organs were fixed in formalin, sagittally sectioned, and evaluated by a pulmonary pathologist blinded to treatment. RESULTS: Antegrade and retrograde flushes demonstrated no significant thrombi. Gross pathologic evaluation revealed no occlusive central thrombi. Scant peripheral thrombi were detected in both treatment groups. No microscopic thrombi were noted in either treatment group. CONCLUSIONS: Delayed heparin administration after cardiac death does not affect thrombus formation in an animal model of lung procurement after cardiac death. Concern about clinically significant thrombosis occurring when heparin is not given before cardiac arrest appears unfounded. These findings suggest that DCD lungs can be used regardless of antemortem heparin administration.

Undifferentiated metastatic carcinoma and myoepithelioma: two rare causes of hypervascular masses of the parapharyngeal space.

We report 2 unusual cases of hypervascular masses in the parapharyngeal space. The first case involved a poorly differentiated metastatic carcinoma of oropharyngeal origin that mimicked a carotid body tumor. The second case involved a highly vascular myoepithelioma located in the parapharyngeal space.

Evaluation of platybasia with MR imaging.

BACKGROUND AND PURPOSE: Platybasia, or abnormal obtuseness of the basal angle, was first measured on plain skull images. At present, evaluation of the brain and skull more commonly involves CT and MR imaging. We evaluated a new MR imaging method of evaluating platybasia. METHODS: We retrospectively evaluated midline sagittal MR images in 200 adults and 50 children. The basal angle of the skull base was measured by using two methods: The standard MR imaging technique measured the angle formed by two lines-one joining the nasion and the center of the pituitary fossa connected by a line joining the anterior border of the foramen magnum and center of the pituitary fossa. The modified technique measured the angle formed by a line across the anterior cranial fossa and dorsum sellae connecting a line along the clivus. RESULTS: With the standard MR imaging technique, we obtained mean angles of 129 degrees +/- 6 degrees for adults and 127 degrees +/- 5 degrees for children, compared with 135.3 degrees (composite mean) in previous series. The modified technique produced values of 117 degrees +/- 6 degrees for adults and 114 degrees +/- 5 degrees for children, which were significantly lower that those of standard MR imaging and traditional radiography (P <.05). CONCLUSION: Both the standard and modified MR imaging techniques produced basal angles lower than those previously reported with standard radiography. The modified technique uses clearly featured landmarks that can be reproduced consistently on midline sagittal T1 images. This technique and its corresponding values can be used as the new standard for evaluating the basal angle.

Long-term durability of bioprosthetic aortic valves: implications from 12,569 implants.

BACKGROUND: Increased life expectancy and younger patients' desire to avoid lifelong anticoagulation requires a better understanding of bioprosthetic valve failure. This study evaluates risk factors associated with explantation for structural valve deterioration (SVD) in a long-term series of Carpentier-Edwards PERIMOUNT aortic valves (AV). METHODS: From June 1982 to January 2011, 12,569 patients underwent AV replacement with Edwards Lifesciences Carpentier-Edwards PERIMOUNT stented bovine pericardial prostheses, models 2700PM (n = 310) or 2700 (n = 12,259). Mean age was 71 ± 11 years (range, 18 to 98 years). 93% had native AV disease, 48% underwent concomitant coronary artery bypass grafting, and 26% had additional valve surgery. There were 81,706 patient-years of systematic follow-up data available for analysis. Demographics, intraoperative variables, and 27,386 echocardiographic records were used to identify risks for explant for SVD and assess longitudinal changes in transprosthesis gradients using time-varying covariable analyses. RESULTS: Three hundred fifty-four explants were performed, with 41% related to endocarditis and 44% to SVD. Actuarial estimates of explant for SVD at 10 and 20 years were 1.9% and 15% overall, respectively, and in patients younger than 60 years, 5.6% and 46%, respectively. Younger age (p < 0.0001), lipid-lowering drugs (p = 0.002), prosthesis-patient mismatch (p = 0.001), and higher postoperative peak and mean AV gradients were associated with explant for SVD (p < 0.0001). The effect of gradient on SVD was greatest in patients younger than 60 years. CONCLUSIONS: Durability of the Carpentier-Edwards PERIMOUNT aortic valve is excellent even in younger patients. Explant for SVD is related to gradient at implantation, especially in younger patients. Strategies to reduce early postoperative AV gradients, such as root enlargement or more efficient prostheses, should be considered.

Growing single-center experience with lung transplantation using donation after cardiac death.

BACKGROUND: Early experience with lung transplantation (LTx) using organs from donors after cardiac death (DCD) has been promising, although widespread adoption has been slow because of the perception of diminished organ quality. Some centers have even suggested that use of DCD lungs is high risk and have recommended ex vivo evaluation before transplantation. We analyzed our growing single-center experience with DCD lungs procured and transplanted using protocols established for brain-dead donors. METHODS: From August 2004 to July 2011, 605 patients underwent LTx, 32 (4.9%) with DCD organs. Standardized donor selection, procurement, and preservation protocols established for brain-dead donors were applied to DCD organs. Measured outcomes were Kaplan-Meier survival, early graft function measured by arterial partial pressure of oxygen/fraction of inspired oxygen (PO2/FIO2 ratio [P/F ratio]), airway complications, spirometry, and development of bronchiolitis obliterans syndrome (BOS). RESULTS: Survival was 97% at 30 days, 91% at 1 year, 91% at 2 years, and 71% at 3 and 4 years. Mean P/F ratio at 6 hours and 24 hours was 305 and 332, respectively. One airway complication required intervention. Median time to extubation, intensive care unit (ICU), and total hospital lengths of stay were 1, 4, and 14 days, respectively. At median follow-up of 2.8 years, median forced expiratory volume in 1 second, percent of predicted (FEV1%) of the survivors was 59% (range, 27%-113%), with 16% (5/32) having BOS. CONCLUSIONS: This growing experience suggests that recipient survival and early graft function using DCD lungs is excellent and has occurred without significant adjustment of procurement, preservation, or implantation protocols. Concerns over diminished organ quality are unfounded, and use of DCD lungs should be expanded.

Donor lungs with pulmonary embolism evaluated with ex vivo lung perfusion.

Acute pulmonary embolism (PE) compromises oxygenation and is typically considered a contraindication to lung donation for transplantation. We report the use of ex vivo lung perfusion (EVLP) to evaluate and possibly improve a pair of donor lungs with PE and poor oxygen exchange to a condition that might have been suitable for subsequent transplantation. A pair of donor lungs was procured for research after being declined for clinical use and placed on the EVLP circuit for 7 hours. Functional monitoring of the lungs revealed an increase in the partial pressure of oxygen to fraction of inspired oxygen ratio (P/F ratio) from 268 in situ to 458 after EVLP. While on the circuit, pulmonary vascular resistance decreased as dynamic compliance of the lungs increased, suggesting they might have been acceptable for transplantation.

Growing experience with extracorporeal membrane oxygenation as a bridge to lung transplantation.

Extracorporeal membrane oxygenation (ECMO) is rarely used as a bridge to lung transplantation (BTT) because of its associated morbidity and mortality. However, recent advancements in perfusion technology and critical care have revived interest in this application of ECMO. We retrospectively reviewed our utilization of ECMO as BTT and evaluated our early and midterm results. Nineteen patients were placed on ECMO with the intent to transplant of which 14 (74%) were successfully transplanted. Early and midterm survival of transplanted patients was 75% (1 year) and 63% (3 years), respectively, with the most favorable results observed in interstitial lung disease patients supported in the venovenous configuration. Extracorporeal membrane oxygenation-bridged transplant survival rates were equivalent to nonbridged recipients, but early morbidity and mortality are high and the failure to bridge to transplant is significant. Overall, successfully bridged patients can derive a tangible benefit, albeit with considerable consumption of resources.