Myocardial perfusion characteristics during machine perfusion for heart transplantation.

BACKGROUND: Optimal parameters for machine perfusion preservation of hearts prior to transplantation have not been determined. We sought to define regional myocardial perfusion characteristics of a machine perfusion device over a range of conditions in a large animal model. METHODS: Dog hearts were connected to a perfusion device (LifeCradle, Organ Transport Systems, Inc, Frisco, TX) and cold perfused at differing flow rates (1) at initial device startup and (2) over the storage interval. Myocardial perfusion was determined by entrapment of colored microspheres. Myocardial oxygen consumption (MVO(2)) was estimated from inflow and outflow oxygen differences. Intra-myocardial lactate was determined by (1)H magnetic resonance spectroscopy. RESULTS: MVO(2) and tissue perfusion increased up to flows of 15 mL/100 g/min, and the ratio of epicardial:endocardial perfusion remained near 1:1. Perfusion at lower flow rates and when low rates were applied during startup resulted in decreased capillary flow and greater non-nutrient flow. Increased tissue perfusion correlated with lower myocardial lactate accumulation but greater edema. CONCLUSIONS: Myocardial perfusion is influenced by flow rates during device startup and during the preservation interval. Relative declines in nutrient flow at low flow rates may reflect greater aortic insufficiency. These factors may need to be considered in clinical transplant protocols using machine perfusion.

Endoscopic management of polyps in a urinary continent catheterizable channel.

We report a case of polyps in a urinary continent catheterizable channel that were endoscopically resected with the holmium laser. An 11-year-old boy underwent lower urinary tract reconstruction, along with a continent catheterizable channel. Due to persistent problems catheterizing, he underwent an endoscopy which revealed multiple broad-based polyps in his channel. These polyps were resected completely with the holmium laser without complication. The polyps were benign on final pathological examination. Follow-up endoscopy 4 weeks later revealed a healthy channel with no residual polyps. The patient has had no difficulties catheterizing in the interim. To our knowledge, this is the only report published of using the holmium laser to resect polyps in a urinary catheterizable channel.

Reflux in cystoplasties.

Vesicoureteral reflux is a commonly encountered condition in pediatric urology. The treatment of vesicoureteral reflux is debated in all patients. Much controversy exists regarding the need to reimplant refluxing ureters at the time of bladder augmentation, particularly in those patients with neuropathic bladders. In patients with neuropathic bladders, reflux may be the result of elevated detrusor pressure, recurrent/persistent urinary tract infections and/or a neuropathic dysfunction at the ureterovesical junction and the trigone. Treatment of VUR in patients undergoing bladder augmentation varies and includes routinely reimplanting all refluxing ureters, selectively reimplanting ureters with high-grade reflux or avoiding anti-reflux surgery in all patients regardless of the grade of reflux. We review the literature and our experience with the treatment of vesicoureteral reflux in patients that have undergone augmentation cystoplasty.

Reflux in cystoplasties / Reflujo en cistoplastias

Vesicoureteral reflux is a commonly encountered condition in pediatric urology. The treatment of vesicoureteral reflux is debated in all patients. Much controversy exists regarding the need to reimplant refluxing ureters at the time of bladder augmentation, particularly in those patients with neuropathic bladders. In patients with neuropathic bladders, reflux may be the result of elevated detrusor pressure, recurrent/persistent urinary tract infections and/or a neuropathic dysfunction at the ureterovesical junction and the trigone. Treatment of VUR in patients undergoing bladder augmentation varies and includes routinely reimplanting all refluxing ureters, selectively reimplanting ureters with high-grade reflux or avoiding anti-reflux surgery in all patients regardless of the grade of reflux. We review the literature and our experience with the treatment of vesicoureteral reflux in patients that have undergone augmentation cystoplasty (AU)

El reflujo vesicoureteral es una condición frecuente en urología pediátrica. El tratamiento en todos los pacientes está en debate. Existe una gran controversia sobre la necesidad de reimplantar los uréteres refluyentes en el momento de la cistoplastia de aumento, especialmente en aquellos pacientes con vejigas neurógenas. En pacientes con vejigas neurógenas, el reflujo puede ser el resultado de una presión elevada del detrusor, de infecciones del tracto urinario recurrentes/persistentes y/o de una disfunción neuropática de la unión ureterovesical y el trígono. El tratamiento del RVU en pacientes sometidos a cistoplastia de aumento varía, incluyendo desde el reimplante rutinario de todos los uréteres refluyentes hasta la evitación de la cirugía antirreflujo en todos los pacientes independientemente del grado del reflujo. Revisamos la literatura y nuestra experiencia con el tratamiento del reflujo vesicoureteral en pacientes sometidos a cistoplastia de aumento (AU)

Ileal enterocystoplasty and B12 deficiency in pediatric patients.

PURPOSE: Vitamin B12 deficiency is a feared complication of enterocystoplasty but it has never been demonstrated in pediatric patients who have undergone ileal enterocystoplasty. We reviewed our series of more than 500 bladder augmentations in an attempt to define the timing and risk of vitamin B12 deficiency in pediatric patients after bladder augmentation. MATERIALS AND METHODS: From October 2004 to present we obtained serum B12 values in patients who had undergone bladder augmentation at our institution. We looked at patients who had undergone ileal enterocystoplasty and who were 18 years or younger at the time of augmentation. Any B12 value that was obtained while on any form of B12 supplementation was excluded. These criteria resulted in 79 patients with 105 B12 values. B12 values of 200 pg/ml or less were considered "low," and values between 201 and 300 pg/ml were considered "low-normal." RESULTS: There was a statistically significant correlation between followup time and serum B12 (p = 0.0001). The probability of low B12 increased as followup time increased (p = 0.007), as did the probability of low-normal B12 (p = 0.005). Starting at 7 years postoperatively 6 of 29 patients (21%) had low B12 values, while 12 of 29 (41%) had low-normal values. CONCLUSIONS: Pediatric patients who have undergone ileal enterocystoplasty are at risk for development of vitamin B12 deficiency. These patients are at the highest risk beginning at 7 years postoperatively, and the risk increases with time. We recommend an annual serum B12 value in children beginning at 5 years following bladder augmentation.

Perfusion preservation versus static preservation for cardiac transplantation: effects on myocardial function and metabolism.

INTRODUCTION: Continuous perfusion of donor hearts for transplantation has received increasing interest, but the effects on cellular metabolism, myocyte necrosis, and myocardial edema are not well defined. METHODS: Pig hearts were instrumented with sonomicrometry crystals and left ventricular catheters. Left ventricular function was quantified by the pre-load-recruitable stroke work (PRSW) relationship. Hearts were arrested with Celsior solution with 5.5 mM 13C-glucose added, and removed and stored in cold solution (n = 4) or placed in a device providing continuous perfusion of this solution at 10 ml/100 g/min (n = 4). After 4 hours of storage, left atrial samples were frozen, extracted, and analyzed by magnetic resonance spectroscopy. Hearts were then transplanted into recipient pigs and reperfused for 6 hours, with function measured hourly. At the end of the experiment, left ventricular water content and serum creatine kinase-MB isoenzyme levels were measured. RESULTS: Baseline left ventricular function was similar in both groups. During reperfusion, the volume-axis intercept of the PRSW relationship was significantly lower in hearts stored with continuous perfusion (p < 0.05), suggesting reduced contractile impairment. Magnetic resonance spectroscopy revealed a decrease in tissue lactate in hearts that received continuous perfusion. Serum creatine kinase-MB isoenzyme levels were higher hearts that had static storage (30.8 +/- 9.0 vs 13.2 +/- 2.7 ng/ml; p < 0.05). Left ventricular water content was similar in both groups (0.797 +/- 0.012 vs 0.796 +/- 0.014; p = 0.45). CONCLUSIONS: Donor hearts sustain less functional impairment after storage with continuous perfusion. This technique reduces tissue lactate accumulation and myocardial necrosis without increasing myocardial edema and appears promising as a method to improve results of cardiac transplantation.

Benefits of perfusion preservation in canine hearts stored for short intervals.

BACKGROUND: Continuous perfusion of donor hearts for transplantation has been proposed to improve graft function or extend preservation intervals, but the effects on cellular metabolism, myocyte loss, and myocardial edema are not well-defined. METHODS: Hearts from mongrel dogs were instrumented with sonomicrometry crystals and left ventricular (LV) catheters. LV function was quantified by the preload-recruitable stroke work (PRSW) relationship. Hearts were arrested with a modified Celsior solution, and stored in cold solution (n=6) or placed in a device providing continuous perfusion of this solution at 10 mL/100 g/min (n=6). After 4 h of storage, left atrial samples were frozen, extracted, and analyzed by magnetic resonance spectroscopy (MRS). Hearts were then transplanted into recipient dogs and reperfused for 6 h with function measured hourly. At end-experiment, LV specimens were assayed for water content and apoptosis. Serum CK-MB levels were measured. RESULTS: LV functional recovery was excellent in both groups over 6 h of reperfusion. MRS revealed a dramatic decrease in tissue lactate in hearts protected with continuous perfusion (P<0.01). Apoptotic cell counts were significantly lower in post-reperfusion heart tissue in animals undergoing a continuous perfusion strategy (P<0.01). CK-MB levels and LV water content were similar in both groups. CONCLUSIONS: Although both methods of preservation lead to good early graft function after 4 h of protected ischemia, continuous preservation dramatically reduces tissue lactate accumulation without increasing myocardial edema and may reduce tissue damage during storage and reperfusion. It appears promising as a method to improve results of cardiac transplantation.

Effects of early steroid withdrawal after heart transplantation.

BACKGROUND: Managing immunosuppression is a significant aspect of posttransplantation patient care. Previously, our institution reported that prednisone could be withdrawn in cardiac allograft recipients without jeopardizing midterm survival. We returned to this group of patients to investigate the long-term effects of our steroid taper protocol. METHODS: We reviewed the records of 162 consecutive cardiac transplant recipients from our institution. Patients who underwent transplantation between 1988 and 1990 were treated with traditional triple-therapy immunosuppression (cyclosporine, azathioprine, and prednisone). Beginning June 1990, we instituted a protocol of early steroid taper with discontinuation by 6 months after transplant. The two groups were comparable with respect to age, sex, ethnicity, cause of heart failure, ischemic time, body mass index, and creatinine at the time of transplantation. RESULTS: Fifty-seven percent of the patients in the early steroid taper group were successfully withdrawn from steroids at 6 months after transplantation. This group had a decreased freedom from and increased frequency of acute rejection (p < 0.01 for each) when compared with the traditional therapy group. There was, however, no difference in freedom from posttransplant coronary artery disease (p = 0.53). The early steroid taper group enjoyed an increased freedom from malignancy (p = 0.01) and trended toward a decreased frequency of infection (p = 0.10) and improved survival (p = 0.06). CONCLUSIONS: Steroid withdrawal is possible in 57% of patients at 6 months after transplantation. The institution of an early steroid taper protocol improves the overall freedom from malignancies and may decrease the frequency of infection and prolong overall survival without increasing the risk of posttransplant coronary artery disease.

Contemporary techniques and safety of cardiovascular procedures in the surgical management of renal cell carcinoma with tumor thrombus.

OBJECTIVE: Renal cell carcinomas often form venous thrombi that extend into the vena cava. Frequently, cardiovascular consultation is necessary for complete surgical excision. We sought to investigate the risk factors, surgical techniques, and outcomes of patients treated for renal cell carcinoma with venous extension. METHODS: We reviewed the records of 46 consecutive patients who underwent surgical management of renal cell carcinoma with venous extension between 1991 and 2005. Data on patient history, staging, surgical techniques, morbidity, and survival were analyzed. RESULTS: There were 29 men and 17 women with a mean age of 60.2 +/- 12.0 years. Twenty-five (54%) procedures were completed with cardiovascular assistance. Nephrectomy was performed in 44 (96%) cases. Three (7%) patients underwent right heart venovenous bypass, and 2 (5%) patients underwent cardiopulmonary bypass with circulatory arrest. Fourteen (32%) patients had perioperative complications, including 1 (2%) perioperative death. Patients who required cardiovascular procedures (inferior vena cava clamping, right heart venovenous bypass, and cardiopulmonary bypass with circulatory arrest) had higher risks of perioperative complications (P < .02). The 1-, 2-, and 5-year overall survival rates were 78%, 69%, and 56%. CONCLUSIONS: This large series demonstrates that aggressive treatment of renal cell carcinoma with venous thrombus provides favorable outcomes. Our 5-year survival is among the highest of recent reviews, and our perioperative morbidity and mortality rates are comparable with those of other series. Tumors that require cardiovascular procedures are associated with increased complications when compared with radical nephrectomy and thrombectomy alone. Nevertheless, this aggressive treatment approach offers encouraging patient survival.

Routine computed tomography screening of the chest in high-risk cardiac transplant recipients may improve survival.

BACKGROUND: Multiple studies have demonstrated an increased incidence of lung cancer in the heart transplant population. We reviewed our cardiac transplantation experience with respect to the development of bronchogenic carcinoma and explored the role of routine chest computed tomography (CT) in its surveillance. METHODS: We performed a review of our cardiac transplantation experience, highlighting the incidence of lung cancer, and we analyzed our recent experience with screening chest CT in lung cancer surveillance in this patient group. RESULTS: Eighteen patients developed 20 cases of bronchogenic carcinoma for an incidence of 6.83%. In 10 cases, the patients underwent surgical resection; however, in the remaining cases, the patients were either treated with chemotherapy and/or radiation or they died before initiation of therapy. The actuarial 1-, 2- and 5-year overall survival rates were 49%, 29% and 13%, respectively. The median survival of patients who underwent surgical resection was 28 months (3 to 85 months), whereas the median survival of patients who were either ineligible for surgery or died before initiation of treatment was only 1 month (1 to 13 months). All patients diagnosed with lung cancer by chest CT underwent surgical resection; however, only 37.5% of patients diagnosed with lung cancer by chest X-ray were found at an appropriate stage for resection (p = 0.025). CONCLUSIONS: Cardiac transplant recipients have a significant risk of developing bronchogenic carcinoma. Routine chest CT screening in high-risk patients may enable clinicians to identify disease earlier, which is essential for the option of surgical resection and, therefore, prolonged survival.

Contemporary assessment of laryngotracheal trauma.

OBJECTIVES: Laryngotracheal trauma is a rare and potentially deadly spectrum of injuries. We sought to characterize the contemporary mechanisms, diagnostic modalities, and outcomes common in laryngotracheal trauma today. METHODS: We performed a retrospective analysis of all laryngotracheal trauma cases at 2 major metropolitan hospitals between 1996 and 2004, detailing mechanisms, associated injuries, diagnostic modalities, and outcomes of laryngotracheal trauma. RESULTS: We identified 71 patients with a mean age of 32.8 +/- 13.3 years (range, 15-71 years). In our series penetrating trauma was the cause in 73.2% of patients; however, blunt trauma had a significantly higher mortality (63.2% vs 13.5%, respectively; P < .0001). Blunt mechanisms involved older patients (38.5 +/- 15.2 years vs 30.1 +/- 11.9 years, P = .017), and these patients were more likely to require emergency airways than those with penetrating trauma (78.9% vs 46.2%, P = .017). The requirement of an emergency airway was an independent predictor of mortality (P = .0066). CONCLUSION: Laryngotracheal trauma is a deadly spectrum of injuries with a mortality of 26.8%. Blunt mechanisms are decreasing in frequency. This might reflect improvements in automobile safety. Additionally, violent crime is on the increase, producing penetrating injuries with increasing frequency. The most fundamental intervention for patients with laryngotracheal injury is airway control. Either routine intubation or a tracheostomy can secure the airway. Blunt trauma and the requirement of an emergency airway are independent predictors of mortality. Laryngotracheal trauma requires prompt recognition, airway protection, and skillful management to lessen the mortality of this deadly spectrum of injuries.

Improved pain management outcomes with continuous infusion of a local anesthetic after thoracotomy.

OBJECTIVE: We sought to determine the effectiveness of an incisional infusion of local anesthetics through a continuous-infusion elastomeric pump for the management of postoperative pain after thoracotomy. METHODS: We performed a retrospective comparative analysis of 110 patients undergoing thoracotomies between November 1999 and March 2003. Postoperative pain management with a continuous-infusion elastomeric pump providing local anesthetic into the incisional area was compared with a single-shot epidural in combination with continuous local anesthetic infusion and continuous thoracic epidural infusion. Data sources were reviewed for mean narcotic use, pain score, and complications. RESULTS: After thoracotomy procedures, 38 patients received the ON-Q Pain Relief System (I-Flow Corp, Lake Forest, Calif), 32 received the ON-Q device and single-shot epidural infusion, and 40 received continuous epidural infusion. Demographic attributes, including age, body mass index, and sex were similar between the groups. Preoperative American Society of Anesthesiologists status was significantly higher in the ON-Q group compared with that in the other groups (P = .02). Narcotic use and pain scores were significantly reduced in the ON-Q group compared with that in the epidural group at all time points (P < .001). There were no wound-healing complications or infections associated with the use of the pump. CONCLUSION: A continuous infusion of 0.25% bupivacaine at 4 mL/h through the ON-Q elastomeric infusion pump is a safe and effective adjunct in postoperative pain management after thoracotomy. The use of the ON-Q Pain Relief System results in decreased narcotic use and lower pain scores compared with continuous epidural infusion.

Surgical treatment of thoracic empyema in HIV-infected patients: severity and treatment modality is associated with CD4 count status.

OBJECTIVES: Patients infected with HIV have an increased propensity for developing thoracic empyemas secondary to their susceptibility to polymicrobial pulmonary infections. We performed an assessment of the clinical outcomes of HIV patients undergoing surgical treatment of thoracic empyemas and reviewed the microbiology of these infections. METHODS: We completed a retrospective analysis of the patients who had been referred for surgical treatment of thoracic empyemas over an 11-year period, ending in 2002. The patients were treated at a major metropolitan medical teaching facility that cares for a substantial number of HIV-positive patients. RESULTS: Twenty-one HIV-infected patients underwent surgical treatment of thoracic empyemas. There were no immediate deaths. Sixty-two percent of the patients had CD4 counts of < 200 cells/microL. Eight patients had postoperative complications. Six of the patients with complications had CD4 counts of < 200 cells/microL. Patients with lower CD4 counts were at risk for mycobacterial and fungal infections. Additionally, they often had complex empyemas that were not favorable for treatment by video-assisted thoracic surgery. Therefore, these patients often required surgery with lung resection, which necessitated longer periods of postoperative chest tube drainage. CONCLUSIONS: Surgeons can obtain satisfactory operative outcomes when treating thoracic empyemas in HIV patients; however, the treatment strategy should be individualized. Patients with CD4 counts of < 200 cells/microL more commonly have complex empyemas that require surgery with open decortication and drainage. Although these patients have a higher incidence of postoperative complications, we think that HIV patients with thoracic empyemas can be safely and effectively treated with surgical techniques.