Curtis G. Tribble

Reperfusion injury significantly impacts clinical outcome after pulmonary transplantation

BACKGROUND Reperfusion injury after pulmonary transplantation can contribute significantly to postoperative pulmonary dysfunction. We hypothesized that posttransplantation reperfusion injury would result in an increase in both in-hospital mortality and morbidity. We also hypothesized that the incidence of reperfusion injury would be dependent upon the cause of recipient lung disease and the interval of donor allograft ischemia. METHODS We performed a retrospective study of all lung transplant recipients at our institution from June 1990 until June 1998. One hundred patients received 120 organs during this time period. We compared two groups of patients in this study: those experiencing a significant reperfusion injury (22%) and those who did not (78%). RESULTS In-hospital mortality was significantly greater in patients experiencing reperfusion injury (40.9% versus 11.7%, p < 0.02). Posttransplantation reperfusion injury also resulted in prolonged ventilation (393.5 versus 56.8 hours, p < 0.001) and an increased length of stay in both the intensive care unit (22.2 versus 10.5 days, p < 0.01) and in the hospital (48.8 versus 25.6 days, p < 0.03). The incidence of reperfusion injury could not be attributed to length of donor organ ischemia (221.5 versus 252.9 minutes, p < 0.20). The clinical impact of reperfusion injury was significantly greater in patients undergoing transplantation for preexisting pulmonary hypertension (6/14) than those with chronic obstructive pulmonary disease or emphysema alone (6/54) (42.9% versus 11.1%, p < 0.012). CONCLUSIONS Clinically significant pulmonary reperfusion injury increased in-hospital mortality and morbidity resulting in prolonged ventilation, length of stay in the intensive care unit, and cost of hospitalization. The incidence of reperfusion injury was not dependent upon the duration of donor organ ischemia but increased with the presence of preoperative pulmonary hypertension. These findings suggest that recipient pathophysiology and donor allograft quality may play important roles in determining the incidence of reperfusion injury.

Ischemia-reperfusion injury after lung transplantation increases risk of late bronchiolitis obliterans syndrome.

BACKGROUND Bronchiolitis obliterans syndrome (BOS) is the most common cause of long-term morbidity and mortality after lung transplantation. Our hypothesis was that early ischemia-reperfusion injury after lung transplantation increases the risk of BOS. METHODS Data on 134 patients who had lung transplantation between January 1, 1990 and January 1, 2000, was used for univariate and multivariate logistic regression analysis. RESULTS After lung transplantation, 115 patients (115 of 134, 86%) survived more than 3 months. In that group, 41 patients developed BOS, of which 23 had progressive disease. Univariate analysis revealed that ischemia-reperfusion injury (p = 0.017) and two or more acute rejection episodes (p = 0.032) were predictors of BOS onset, whereas ischemia-reperfusion injury (p = 0.011) and cytomegalovirus infection (p = 0.009) predicted progressive BOS. Multivariate logistic regression analysis showed that ischemia-reperfusion injury was an independent predictor for both BOS development and BOS progression. Two or more acute rejection episodes were also an independent predictor of BOS development, whereas cytomegalovirus infection was an independent predictor of progressive BOS. CONCLUSIONS Ischemia-reperfusion injury increases the risk of BOS after lung transplantation.

Percutaneous transluminal angioplasty and stenting in the treatment of chronic mesenteric ischemia: results and longterm followup

BACKGROUND The purpose of this study was to review the results of percutaneous transluminal angioplasty (PTA), stenting, or both in the treatment of patients who present with symptoms and angiographic findings most consistent with chronic mesenteric ischemia. STUDY DESIGN A retrospective analysis of 33 consecutive patients from a single institution who underwent PTA, stenting, or both for treatment of symptoms most characteristic of chronic mesenteric ischemia was performed. RESULTS There were 12 men and 21 women with a mean age of 63 years (range 40 to 89 years). Median weight loss was 28 lb (range 6 to 80 lb). Postprandial pain was present in 88% of the patients (29 of 33). All lesions treated were stenoses. PTA alone was performed in 21 patients (32 vessels), and PTA and stenting were performed in 12 patients (15 vessels). PTA was technically successful in 26 of 32 vessels (81.3%); PTA plus stenting was technically successful in 15 of 15 vessels (100%) (p = 0.073). Complete alleviation of symptoms occurred immediately in 27 of the patients (82%), and 2 patients (6%) had significant improvement in symptoms. There were four immediate clinical failures (12%): two patients were found to have occult malignancy and one had immediate relief of symptoms after surgical release of the median arcuate ligament. Followup data were obtained in all patients with clinically successful procedures (mean 38 months, median 25 months, range 1 to 123 months). Angiographic followup was available in 52% of the patients (15 of 29), at a mean of 20 months. The primary longterm clinical success rate was 83.3% (24 of 29). Four of the five patients with recurrent symptoms were successfully retreated with endovascular therapy. The primary assisted longterm clinical success rate was 96.6% (28 of 29). The 5-year survival rate was 76.1%. Major complications occurred in 13% of the procedures, with a 30-day mortality rate of 0%. CONCLUSION Endovascular therapy for treatment of mesenteric arterial stenoses is effective in the treatment of patients with symptoms and angiographic findings characteristic of chronic mesenteric ischemia.

Percutaneous Transluminal Angioplasty of Visceral Arterial Stenoses: Results and Long-term Clinical Follow-up

PURPOSE To determine the efficacy and safety of percutaneous transluminal angioplasty (PTA) of the visceral arteries. PATIENTS AND METHODS We retrospectively evaluated the results of PTA performed in 20 visceral arteries in 19 patients (10 men, nine women; mean age, 63 years). Eleven patients had symptoms characteristic of mesenteric ischemia, four had atypical abdominal pain, and four were undergoing prophylactic dilation before undergoing another procedure involving the abdominal aorta. Clinical follow-up was possible in all patients. RESULTS PTA was technically successful in 15 of 19 patients (79%); among these 15 patients, 12 (80%) did well clinically. Of the seven PTA procedures that were immediate failures, five failed secondary to an occult malignancy or to extrinsic arterial compression by the median arcuate ligament. Ten (83%) of the 12 patients in whom the procedures were immediate clinical successes are still clinically improved at 4-73 months follow-up (mean, 25 months). PTA was successful in only one of the four patients who had symptoms atypical of mesenteric ischemia, but it was successful in 11 of the 15 patients who had symptoms of mesenteric ischemia or who underwent prophylactic dilation. Major complications occurred in three (16%) of the 19 patients. CONCLUSION PTA of visceral artery stenoses is effective in patients with symptoms of mesenteric ischemia. It is also effective as prophylaxis in patients undergoing additional procedures in the abdominal aorta.

Prevention of spinal cord injury after repair of the thoracic or thoracoabdominal aorta

Spinal cord injury occurring as the result of surgical repair of thoracic and thoracoabdominal aortic disease remains a devastating complication. The incidence of postoperative neurologic deficits varies from 4% to 38%. Factors associated with a greater risk for injury include the presence of dissection or extensive thoracoabdominal disease, and a prolonged cross-clamp time. Spinal cord ischemia initiates a deleterious cascade of biochemical events that ultimately result in an increased intracellular calcium concentration. Calcium-activated proteases, lipases, and nucleases mediate the processes that cause cell injury. The accumulation of oxygen-derived free radicals and the occurrence of hyperemia during reperfusion are also contributing causes of spinal cord injury. Increasing the spinal cord blood flow with shunts, oxygenated bypass circuits, cerebrospinal fluid drainage, the intrathecal administration of vasodilators, and the reattachment of intercostal arteries has been tried in an effort to increase spinal cord perfusion. Pharmacologically based measures to prevent spinal cord injury have been pursued, and these have consisted of hypothermia, anesthetic agents, calcium channel blockers, free radical scavengers, and immune system modulation. However, no single technique has proved to be consistently effective in preventing ischemia-induced spinal cord injury.

Use of video-assisted thoracic surgery in the treatment of chylothorax.

Chylothorax, a potentially lethal disorder that may cause profound respiratory, nutritional, and immunologic complications, has become increasingly common in recent years. Medical therapy has been found to have a significant failure rate. Therefore, surgical treatment of complicated chylothorax has become a mainstay of care. Between 1987 and 1993, ten patients at the University of Virginia Hospital were treated with video-assisted thoracic surgery for complicated chylothorax. Twelve thoracoscopic procedures were performed. Patients ranged in age from 7 months to 82 years. Causes included iatrogenic (2), congenital (2), caval thrombosis (2), amyloid (2), blunt trauma (1), and metastatic carcinoid tumor (1). In 10 cases, video-assisted thoracic surgery was employed as the principal mode of therapy: 8 using talc pleurodesis alone, 1 using talc pleurodesis and clipping of the thoracic duct with application of fibrin glue, and 1 requiring clipping of a pleural defect with application of fibrin glue. In 2 cases, a video-assisted thoracic operation was used in conjunction with pleuroperitoneal shunting: a previously placed pleuroperitoneal shunt that was malfunctioning was repositioned thoracoscopically after a pleural adhesiolysis, and a pleural adhesiolysis was performed thoracoscopically before placement of a pleuroperitoneal shunt. In all cases the effusion resolved after the video-assisted thoracic operation without further intervention. Video-assisted thoracic surgery offers an effective means of treating chylothorax, regardless of cause, allowing the advantage of access to thoracic structures without the morbidity of more extensive procedures.

Thoracoscopic diagnosis and treatment of mediastinal masses

Evaluation of mediastinal masses often involves an array of imaging procedures and percutaneous biopsy techniques. Despite this, surgical intervention with an open biopsy is often required, especially to diagnose mediastinal malignancies. We report 22 patients with mediastinal masses who were managed with thoracoscopic biopsy, as opposed to open biopsy. All of these patients either had unsuccessful fine-needle aspiration or were unacceptable candidates for percutaneous aspiration. The patients ranged in age from 11 months to 67 years with a mean age of 17.2 +/- 3.6 years. Thoracoscopy provided an accurate tissue diagnosis in 19 of the 22 patients (86%) without need for an open diagnostic procedure. In 1 patient, histoplasmosis was suspected from the thoracoscopic biopsy, but open thoracotomy was needed for confirmation. Of the 19 patients with a positive tissue diagnosis, 3 patients had bronchogenic cysts that were completely resected by thoracoscopy. The mean duration of chest tube drainage was 2.3 +/- 0.2 days, and there were no complications or procedure-related deaths. The average length of hospitalization was 6.0 +/- 0.8 days. We believe that thoracoscopy is a safe, rapid, and effective modality for the diagnosis of mediastinal masses. Accurate tissue diagnoses are obtained in most patients without the need for additional procedures. In addition, we have demonstrated that complete excision of certain benign lesions during thoracoscopy is possible.

Intraoperative Hetastarch Infusion Impairs Hemostasis After Cardiac Operations

BACKGROUND An outbreak of excessive bleeding after cardiac operations occurred at our institution when 5% albumin was in short supply and hetastarch became the preferred intraoperative colloid. As hetastarch may impair coagulation, we investigated the effects of its intraoperative administration on post-cardiac surgical hemostasis. METHODS Indices of postoperative hemostasis were analyzed in 189 consecutive patients undergoing coronary artery bypass grafting. Three groups were compared: one group (n = 68) received a mean of 796 mL of hetastarch only in the operating room (a few minutes after cessation of cardiopulmonary bypass), another group (n = 59) received a mean of 856 mL postoperatively only, and a third group (n = 62) received no hetastarch. RESULTS Compared with the other two groups, those patients administered hetastarch intraoperatively exhibited significant reductions in hematocrit and platelet count, a significant prolongation in the prothrombin time, and significant increases in both blood loss and hemostatic drug requirement. Also identified were obvious trends toward a greater transfusion requirement and reexploration rate for bleeding in the latter group. CONCLUSIONS Hetastarch infusion just after weaning from cardiopulmonary bypass produces a clinically important impairment in post-cardiac surgical hemostasis. Intraoperative use of this agent during heart operations should be avoided until the safe timing of its administration is clarified.

Successful transplantation of marginally acceptable thoracic organs.

OBJECTIVE This study evaluates the efficacy of personally inspecting marginal thoracic organ donors to expand the donor pool. SUMMARY BACKGROUND DATA The present donor criteria for heart and lung transplantation are very strict and result in exclusion of many potential thoracic organ donors. Due to a limited donor pool, 20-30% of patients die waiting for transplantation. METHODS The authors have performed a prospective study of personally inspecting marginal donor organs that previously would have been rejected by standard donor criteria. RESULTS Fourteen marginal hearts and eleven marginal lungs were inspected. All 14 marginal hearts and 10 of the marginal lungs were transplanted. All cardiac transplant patients did well. The mean ejection fraction of the donor hearts preoperatively was 39 +/- 11% (range 15-50%). Postoperatively, the ejection fraction of the donor hearts improved significantly to 55 +/- 3% (p < 0.002). Nine of the ten lung transplant patients did well and were operative survivors. Our donor pool expanded by 36% over the study period. CONCLUSIONS The present donor criteria for heart and lung transplantation are too strict. Personal inspection of marginal thoracic donor organs will help to maximize donor utilization.

Four years' experience with fibrin sealant in thoracic and cardiovascular surgery

A single-donor fibrin sealant system was used in 689 thoracic and cardiovascular surgical procedures over the 4-year period between April 1, 1985, and March 31, 1989. An excellent overall success rate (646/689, 94% effective) was achieved with specific applications, including reduction of leakage of air (29/33, 88% effective), blood (595/634, 94% effective), and fluid (14/14, 100% effective), as well as positioning of anatomical structures such as coronary bypass grafts (8/8, 100% effective). Application methods included use of spray bottles (477/497, 96% effective), syringes (165/186, 89% effective), and a Silastic cannula through the flexible fiber-optic bronchoscope (4/6, 67% effective). The system was used in a wide variety of cardiac, pulmonary, esophageal, and vascular procedures to seal staple lines, suture lines, anastomoses, conduits, fistulas, and raw surfaces. No complications with this single-donor system secondary to blood-borne disease have been documented. Overall infection occurred at a nominal rate (16/689, 2%). Thus, fibrin sealant has been a useful tool to control the leakage of air, blood, and fluid during a wide variety of thoracic and cardiovascular procedures and may be of benefit to other surgeons.