Ferret lung transplant: an orthotopic model of obliterative bronchiolitis

Obliterative bronchiolitis (OB) is the primary cause of late morbidity and mortality following lung transplantation. Current animal models do not reliably develop OB pathology. Given the similarities between ferret and human lung biology, we hypothesized an orthotopic ferret lung allograft would develop OB. Orthotopic left lower lobe transplants were successfully performed in 22 outbred domestic ferrets in the absence of immunosuppression (IS; n = 5) and presence of varying IS protocols (n = 17). CT scans were performed to evaluate the allografts. At intervals between 3-6 months the allografts were examined histologically for evidence of acute/chronic rejection. IS protects allografts from acute rejection and early graft loss. Reduction of IS dosage by 50% allowed development of controlled rejection. Allografts developed infiltrates on CT and classic histologic acute rejection and lymphocytic bronchiolitis. Cycling of IS, to induce repeated episodes of controlled rejection, promoted classic histologic hallmarks of OB including fibrosis-associated occlusion of the bronchiolar airways in all allografts of long-term survivors. In conclusion, we have developed an orthotopic lung transplant model in the ferret with documented long-term functional allograft survival. Allografts develop acute rejection and lymphocytic bronchiolitis, similar to humans. Long-term survivors develop histologic changes in the allografts that are hallmarks of OB.

Short-term and long-term outcomes after bilateral lung volume reduction surgery : prediction by quantitative CT

OBJECTIVES

To evaluate selection criteria and duration of benefit for patients undergoing lung volume reduction surgery (LVRS).

METHODS

Eighty-nine consecutive patients with severe emphysema who underwent bilateral LVRS were prospectively followed up for up to 3 years. Patients underwent preoperative pulmonary function testing, 6-min walk, chest CT, and answered a baseline dyspnea questionnaire. CT scans in 65 patients were analyzed for emphysema extent and distribution using the percentage of emphysema in the lung, percentage of normal lower lung, and the CT emphysema ratio (CTR, an index of the craniocaudal distribution of emphysema). All patients underwent at least 6 weeks of pulmonary rehabilitation prior to surgery. Outcome measures were FEV(1), 6-min walk distance, and transitional dyspnea index (TDI).

RESULTS

Compared to baseline, FEV(1) was significantly increased at 3, 6, 12, 18, 24, and 36 months after surgery (p < or = 0.008). The 6-min walk distance increased from 871 feet (baseline) to 1,110 feet (3 months), 1,214 feet (6 months), 1,326 feet (12 months), 1,342 feet (18 months), 1,371 feet (24 months), and 1,390 feet (36 months) after surgery. Despite a decline in FEV(1) over time, 6-min walk distance was preserved. Dyspnea as measured by TDI improved at 3, 6, 12, 18, 24, and 36 months after surgery. A high CTR was the best predictor of a 12% increase over baseline and an absolute increase of 200 mL in FEV(1), although with a low area under the receiver operating characteristic curve. In addition, the sensitivity and negative predictive value of the CTR were limited. No radiographic or physiologic predictor was able to consistently predict a successful increase in walk distance or TDI.

CONCLUSION

LVRS improves pulmonary function, decreases dyspnea, and enhances exercise capacity in many patients with severe emphysema, although improvement wanes 36 months after surgery.

Randomized trial of preoperative chemoradiation versus surgery alone in patients with locoregional esophageal carcinoma

PURPOSE

A pilot study of 43 patients with potentially resectable esophageal carcinoma treated with an intensive regimen of preoperative chemoradiation with cisplatin, fluorouracil, and vinblastine before surgery showed a median survival of 29 months in comparison with the 12-month median survival of 100 historical controls treated with surgery alone at the same institution. We designed a randomized trial to compare survival for patients treated with this preoperative chemoradiation regimen versus surgery alone.

MATERIALS AND METHODS

One hundred patients with esophageal carcinoma were randomized to receive either surgery alone (arm I) or preoperative chemoradiation (arm II) with cisplatin 20 mg/m2/d on days 1 through 5 and 17 through 21, fluorouracil 300 mg/m2/d on days 1 through 21, and vinblastine 1 mg/m2/d on days 1 through 4 and 17 through 20. Radiotherapy consisted of 1.5-Gy fractions twice daily, Monday through Friday over 21 days, to a total dose of 45 Gy. Transhiatal esophagectomy with a cervical esophagogastric anastomosis was performed on approximately day 42.

RESULTS

At median follow-up of 8.2 years, there is no significant difference in survival between the treatment arms. Median survival is 17.6 months in arm I and 16.9 months in arm II. Survival at 3 years was 16% in arm I and 30% in arm II (P = .15). This study was statistically powered to detect a relatively large increase in median survival from 1 year to 2.2 years, with at least 80% power.

CONCLUSION

This randomized trial of preoperative chemoradiation versus surgery alone for patients with potentially resectable esophageal carcinoma did not demonstrate a statistically significant survival difference.

Neonatal aortic stenosis

Aortic stenosis in the neonate has been associated in the past with a high operative mortality. As a result, in the current era of percutaneous balloon dilatation, the optimal mode of therapy remains controversial. An approach of stabilization with cardiopulmonary bypass, followed by relief of left ventricular outflow tract obstruction, was used at three institutions, and the results are presented. During the period 1983 to 1989, 40 neonates with isolated aortic stenosis and patent ductus arteriosus or coarctation of the aorta, or both, underwent operative therapy. Ages ranged from 1 to 30 days, median of 12 days, including 17 patients in the first week of life. There were 30 boys and 10 girls; weights ranged from 2.5 to 5.5 kg with a mean of 3.6 kg. Perioperative conditions included congestive heart failure in 38 and mitral regurgitation in 16; left ventricular-aortic gradients ranged from 15 to 130 mm Hg, with a mean of 67 mm Hg. There were 30 open valvotomies and 10 transventricular dilatations. The hospital survival rate was 87.5% (35/40) with no significant difference between the methods of valvotomy (9/10 in the transventricular dilatation group, 90%; 26/30 in the open valvotomy group, 87%). Although multiple methods of perfusion and valvotomy were used, the single unifying factor of cardiopulmonary bypass stabilization was present in all 40 patients. No significant difference in survival was noted between institutions, methods of cardiopulmonary bypass, cardiopulmonary bypass times, crossclamp times, or method of valvotomy. There have been five reoperations, with one late death in a patient requiring mitral valve replacement and an apical-aortic conduit. One sudden death occurred; autopsy revealed endocardial fibroelastosis. Results demonstrate that in the three institutions using the methods described, a high operative and late survival rate is possible. The results of this technique, against which percutaneous dilatation should be compared, are standard in the current era.

Operative angiography by intraarterial digital subtraction angiography: a new technique for quality control of carotid endarterectomy

Fifty patients who had carotid bifurcation endarterectomy as their sole surgical procedure underwent intraoperative completion angiography by means of portable intraarterial digital subtraction angiography. All had subsequent intravenous digital subtraction angiography or duplex scanning during early follow-up. After the endarterectomy site was closed and before the wound was closed, 6 to 8 ml of contrast was injected through a 21-gauge needle while fluoroscopy was performed with a conventional C-arm. The C-arm was coupled to a Quantel IDIS Mobile Digital Subtraction Angiogram Unit (Quantel Medical Products Group, Clemmons, N.C.) for image enhancement and immediate playback. There were no postoperative deaths or neurologic complications. Abnormal radiographic results led to reopening of endarterectomy sites in eight patients, which resulted in successful correction of the defects. There was a single asymptomatic occlusion of the internal carotid artery at 3 weeks in the patient with the only false-negative result on the completion study. Intraarterial digital subtraction angiography is a safe and useful technique for intraoperative quality control of carotid endarterectomy. It provides visual images that can be easily repeated in several projections, uses small volumes of contrast, and has no timing requirements for filming and injecting.