Autotransfusion of shed mediastinal blood: a risk factor for mediastinitis after cardiac surgery? Results of a cluster investigation

RATIONALE: After the introduction of autotransfusion of shed mediastinal blood following cardiac surgery, the incidence of mediastinitis increased. The role of autotransfusion in the increased occurrence of this serious complication was examined. METHODS: Using a case-control design, the preoperative, intraoperative, and postoperative characteristics of 11 patients with mediastinitis were compared to those of 33 randomly selected patients undergoing cardiac surgery between September 1, 2000, and April 15, 2001 (control subjects). RESULTS: Patients with mediastinitis were significantly more likely to have a body mass index > 30 (unadjusted odds ratio [OR], 9.9; 95% confidence interval [CI], 2.3 to 42.5), to have received antibiotic therapy during the 2 weeks prior to cardiac surgery (OR, 12.0; 95% CI, 1.1 to 131), or to have required re-exploration within 24 h of the original operation (OR, 8.3; 95% CI, 1.8 to 39). Patients with mediastinitis had 3.4 known risk factors for mediastinitis, compared to only 1.4 risk factors per control subject (p = 0.0001), and longer duration of autotransfusion. After adjustment for other risk factors, autotransfusion for > 6 h was significantly associated with the development of mediastinitis (adjusted OR, 11.9; 95% CI, 1.4 to 97.2). CONCLUSION: Retransfusion of shed mediastinal blood for > 6 h after cardiac surgery was an independent risk factor for mediastinitis.     

Fibrosing mediastinitis with severe bilateral pulmonary artery narrowing: RV-RPA bypass with a homograft conduit

Although fibrosing mediastinitis is uncommon, it is a devastating sequela of certain granulomatous diseases. The compression of mediastinal structures can lead to severe cardiopulmonary symptoms. We report the case of a 50-year-old woman who presented with severe bilateral branch pulmonary artery compression 6 months after bilateral pulmonary artery stenting. We performed bypass surgery with use of a homograft conduit. Seven months postoperatively, the homograft and stent in the right pulmonary artery were patent, and the patient had resumed activities of daily living, including full-time employment. In addition to reporting this patient's case, we discuss surgery as an alternative to stenting in patients with fibrosing mediastinitis.     

Akute Mediastinitis

Acute mediastinitis, an inflammation involving the mediastinal organs and mediastinal connective tissue, requires aggressive surgical treatment. Data suggest high mortality. The vast majority of acute mediastinal infections arise either from perforation of the esophagus or from transsternal cardiac procedures. A small number of cases result from a spreading infection from the head and neck (descending necrotizing mediastinitis). An uncommon cause is iatrogenic infected mediastinitis due to other medical procedures.     

Anaerobic wound infection: Bacteroides mediastinitis after cardiovascular surgery

A case of postoperative anaerobic mediastinitis after coronary artery bypass grafting is reviewed. One of the causative organisms, Bacteroides oralis, has never previously been described as a pathogen causing mediastinitis after median sternotomy incision. There was associated Bacteroides fragilis bacteremia. Only three cases of Bacteroides species mediastinitis after open heart surgery have been reported. This anaerobic bacterium remains a rare pathogen in median sternotomy infections despite the increasing number of cases of mediastinitis seen in association with the burgeoning number of patients undergoing cardiac surgery. Multiple risk factors may contribute to mediastinal infections, which occur in about 2% of patients undergoing coronary artery surgery. When infection occurs, aerobic and anaerobic wound cultures should be made and appropriate antimicrobial and surgical therapy instituted.     

Mediastinitis and mycotic aneurysm of the aorta after orthotopic heart transplantation

After cardiac transplantation, bacterial mediastinitis is a rare but dangerous early complication. Of the 113 patients who underwent heart or heart-lung transplantation at our hospital from August 1981 to April 1989, 8 developed purulent mediastinitis. Treatment involved surgical débridment, local irrigation, drainage, and high-dose systemic antibiotics. No patient died of an acute mediastinal infection. In 2 cases, however, chronic mediastinitis led to the formation of a huge mycotic aneurysm of the ascending aorta. Eleven days after surgical intervention for rupture, 1 patient died of aneurysmal rerupture; the 2nd patient remains well 16 months after prosthetic replacement of the ascending aorta and reconstruction of the necrotic proximal portion of the left coronary artery with a saphenous vein patch.     

Surgical implications of sclerosing mediastinitis. A report of six cases and review of the literature

Sclerosing mediastinitis is an uncommon disease associated with a multiplicity of clinical syndromes. The cause of this disorder is probably an abnormal fibroproliferative response to an inflammatory stimulus, most commonly a granulomatous infection secondary to Histoplasma capsulatum. The pathophysiology of this disease is predicated on the encasement of mediastinal vital organ structures within a dense fibrotic mass. This mass appears to emanate from an invasive chronic inflammatory process causing erosion as well as external compression of these structures. The following case reports illustrate the diversity of this disease entity, representing a patient population from the Ohio River Valley, endemic for histoplasmosis. The purpose of this report is to elucidate the various clinical manifestations of sclerosing mediastinitis and to correlate the pathologic process with a rational approach to treatment.     

Mycotic ascending aortic pseudoaneurysm secondary to pseudomonas mediastinitis at the aortic cannulation site

During the last 5 years, postoperative Pseudomonas mediastinitis has occurred in 2 of the 3,072 patients in our institution who have undergone cardiopulmonary bypass cardiac operations via a sternotomy. To our knowledge, there is no prior report in the English-language literature of postoperative Pseudomonas mediastinitis that originated at the aortic cannulation site, yet that was the site of origin in both of these patients. The 1st patient developed a mycotic pseudoaneurysm of the ascending aorta at the cannulation site, secondary to the development of Pseudomonas mediastinitis following aortic valve replacement. This sequela was successfully treated by means of aneurysmectomy and closure of the aorta with a bovine pericardial patch, under cardiopulmonary bypass with circulatory arrest. The 2nd patient developed pseudoaneurysm and perforation of the aorta at the cardioplegia needle site, secondary to Pseudomonas mediastinitis following aortic and mitral valve replacement. This patient died. In both patients, the cannulation site and the cardioplegia needle site had been closed with pledgeted sutures. Pseudomonas aeruginosa was cultured from both sites. Once the diagnosis of Pseudomonas mediastinitis is made following heart surgery, the patient should undergo reoperation, if possible, for removal of the foreign bodies (pledgeted sutures). In addition, these patients should be monitored with chest magnetic resonance angiography every 3 months for 1 year, in order to diagnose early development of a mycotic pseudoaneurysm and subsequent complications.     

Comparison and evaluation of experimental mediastinitis models: precolonized foreign body implants and bacterial suspension inoculation seems promising

Background  

Post-sternotomy mediastinitis (PSM) is a devastating surgical complication affecting 1–3% of patients that undergo cardiac surgery. Staphylococcus aureus is one of the most commonly encountered bacterial pathogen cultured from mediastinal samples obtained from patients with PSM. A component of the membrane of the gram positive bacteria, lipoteichoic acid, stimulates the blood monocytes and macrophages to secrete cytokines, radicals and nitrogen species leading to oxido-inflammatory damage. This seems to be responsible for the high mortality rate in PSM. For the evaluation of the pathogenesis of infection or for the investigation of alternative treatment models in infection, no standard model of mediastinitis seems to be available. In this study, we evaluated four mediastinitis models in rats.     

Mediastinal granuloma and fibrosing mediastinitis.

Thirty-one patients with mediastinal granuloma and fibrosing mediastinitis were seen at the Mayo Clinic from 1975 through 1977. Review of this series reveals that surgery is necessary to establish a diagnosis if the lesions are noncalcified and indeterminate. Fibrosing mediastinitis most likely develops after rupture of the fibrocaseous material from mediastinal lymph nodes into the mediastinum. Thoracotomy, with evacuation of the granulomas, is recommended, especially when the lesions are large, in order to prevent subsequent fibrosing mediastinitis with involvement of the contiguous structures, such as the superior vena cava, azygos vein, trachea, esophagus, and left atrium. In most patients, obstruction of the superior vena cava develops slowly, and efficient collateral venous circulation occurs, allowing long-term survival and minimal disability.     

Results of Intravascular Stent Placement for Fibrosing Mediastinitis

Objective. Fibrosing mediastinitis is a rare disorder characterized by an excessive fibrotic reaction in the mediastinum which can result in compromise of mediastinal structures. We sought to evaluate short- and midterm results of intravascular thoracic vessel stent placement for patients with fibrosing mediastinitis. Design. We reviewed all records of fibrosing mediastinitis patients who were referred for stent placement to treat mediastinal vascular compression over a 7-year period. Catheterization reports and digital angiography were assessed to determine vessel dimension and stent characteristics. Patients. Thirteen catheterizations were performed in six patients (five females, mean age 39 years, range 23–63) with a range of 1–4 per patient. Interventions. Four patients were treated with intravascular stents placed percutaneously. One patient underwent surgical intravascular stent placement, and one patient declined surgical therapy. The right pulmonary artery was treated in three patients, the superior vena cava was treated in one patient, and three pulmonary veins were treated in one patient. Outcome Measures. Pertinent vessel and hemodynamics including immediate short-, and mid-term results were assessed. Procedural complications, midterm follow-up (up to 7 years), and overall survival were determined. Results. Each intervention resulted in hemodynamic improvement with subsequent clinical improvement. Reintervention was required within 12 months in two of four percutaneously treated patients. One death occurred 4 days after cutting balloon angioplasty in a preexisting pulmonary vein stent. Conclusions. Percutaneous therapy for vessel compression secondary to fibrosing mediastinitis is an option that is effective in improving short-term vascular patency. In-stent stenosis was a frequent complication in patients with fibrosing mediastinitis, particularly when pulmonary veins were involved. Short- and midterm success can be achieved, but progressive fibrosing mediastinitis remains a difficult clinical problem with repeat dilation of stents and/or additional stent placement necessary to maintain optimal stent patency and improvement in clinical symptomatology.     

A case of fibrosing mediastinitis manifesting recurrent nerve palsy]

A 68 year-old man was referred and admitted to our hospital because of hoarseness due to recurrent nerve palsy and an anterior mediastinal tumor detected on chest CT. Chest CT showed a low-density tumor surrounding the aorta and branching arteries. Chest MRI revealed a low-intensity tumor in both T1- and T2-weighted images. The tumor was adjacent to the heart and aorta in the upper anterior mediastinum. A biopsy was performed under minimally invasive video-assisted thoracic surgery (VATS) and a diagnosis of fibrosing mediastinitis was made histopathologically. Oral prednisolone treatment markedly reduced the tumor and improved not only abnormal laboratory data such as C-reactive protein, but also the hoarseness. We report herein that steroid monotherapy was successful in treating a case of fibrosing mediastinitis manifesting recurrent nerve palsy.     

延迟关胸技术在小儿开胸心脏术后的应用

目的介绍延迟关胸技术在先天性心脏病手术中的应用。方法研究阜外医院心外科2001年1月～2002年12月期间小儿开胸心脏手术的临床资料,其中有8例成功延迟关胸,并痊愈出院。结果延迟关胸的原因1例为出血,其他7例为血液动力学不稳定。胸骨敞开时间平均为3.1d(2～5d)。延迟关胸后,血管活性药物剂量明显下降,血液动力学稳定,其中平均动脉压上升15.4mmHg(1～24.6mmHg)。结论对于小儿开胸心脏手术后出现的血液动力学不稳定、低心排、出血,延迟关胸是一种安全而有效的解决方法。     

A clinical trial to investigate the effect of silver nylon dressings on mediastinitis rates in postoperative cardiac sternotomy incisions

Mediastinitis is a rare but serious postoperative complication of cardiac surgery that increases mortality rates, hospital length of stay, and medical costs. A clinical trial was conducted to investigate whether the type of postoperative surgical dressing (silver nylon or standard gauze) affects the rate of mediastinal infections. The sample consisted of 1,600 surgical cardiac patients. Infection rates in the standard gauze group (control, n = 1,235) were collected retrospectively from 24 months of infection control records. In the prospective treatment arm of the study, the wounds of all consecutive surgical patients (n = 365) were covered with a silver nylon dressing and patients were assessed during the 3-week postoperative visit. Thirteen (13) patients in the control group (1%) and none of the patients in the treatment group developed mediastinitis (chi2 [1, N = 1,600] = 3.88, P <0.05). Study findings support the need for a large, prospective, controlled clinical study to confirm the effects of these dressings on mediastinitis, resultant morbidity, and costs of care.     

Computed tomography and the idiopathic form of proliferative fibrosing mediastinitis

Fibrosing mediastinitis is characterized by abnormal proliferation of acellular collagen and fibrous tissue in the mediastinum. Although most cases in the United States are attributed to Histoplasma capsulatum, there is a different and important idiopathic subset, with potentially different treatment and prognosis implications. We reviewed 12 such cases encountered from 1995 to 2004. Computed tomography showed that the masses were large, averaging 5 x 9 cm, with none showing significant calcification. Five had extension into the neck, and all had some vascular or airway involvement. Mimics may include the precalcific form of postinflammatory mediastinal fibrosis, mediastinal granuloma, malignancy (esp. lymphoma), sarcoidosis, and Castleman disease.     

Diagnosis of benign cysts of the mediastinum: the role and risks of EUS and FNA

BACKGROUND: Benign mediastinal cysts, which account for approximately 20% of mediastinal masses, may be diagnostic challenges. Information regarding the use of EUS and EUS-guided FNA in this setting is limited. The aim of this study was to demonstrate the value and potential risks of EUS and EUS-FNA in the diagnosis of mediastinal foregut cysts. METHODS: The EUS database of a single tertiary referral center was reviewed for the diagnosis of benign mediastinal cysts. Twenty patients were identified who underwent 23 EUS examinations for suspected mediastinal cysts (n = 4), for follow-up of a known cyst (n = 3), or for a mediastinal mass of unknown origin (n = 16). RESULTS: In 19 patients, the definite diagnosis of a mediastinal cyst was established by EUS. Twelve cysts appeared anechoic, 6 were hypoechoic, and one anechoic cyst contained small echoic foci. CT (n = 17) or magnetic resonance imaging (n = 1) was performed in 18 cases; only 4 of these were diagnostic of a cyst. In 3 cases, the cyst contents were aspirated by EUS-FNA. In a fourth case, a solid-appearing duplication cyst, misdiagnosed by EUS, was sampled with FNA and core biopsy. This patient developed severe sepsis secondary to mediastinitis 4 days later. Thoracotomy revealed an infected bronchogenic cyst. CONCLUSIONS: EUS provides a minimally invasive approach to the diagnosis of benign mediastinal cysts and may be more accurate than CT or other imaging modalities. Aspiration of suspected cysts should be undertaken with caution, given the risk of infection.     

A case of fibrosing mediastinitis with obstruction of superior vena cava and downhill esophageal varices: a rare cause of upper gastrointestinal hemorrhage

Fibrosing mediastinitis (FM) is an excessive fibrotic reaction that occurs in the mediastinum and may lead to compression of mediastinal structures (especially vascular or bronchial). In the present study we describe the first case report of FM, in a patient who developed downhill esophageal varices and bleeding, which was secondary to superior vena cava obstruction.     

Detection of occult pericardial hemorrhage early after open-heart surgery using technetium-99m red blood cell radionuclide ventriculography

Pericardial or mediastinal hemorrhage requiring reoperation occurs in 2% to 5% of patients, usually early (0 to 48 hours), after open-heart surgery. This hemorrhage may be occult, and resulting cardiac tamponade may easily be misinterpreted as ventricular dysfunction, common early postoperatively. In such cases, appropriate and timely intervention may not occur. Of 50 patients evaluated by technetium-99m red blood cell gated equilibrium radionuclide ventriculography (RNV) because of early postoperative cardiogenic shock of uncertain etiology, 17 had unique scintigraphic images suggestive of intrathoracic hemorrhage. Of these 17, 5 had a generalized “halo” of abnormal radioactivity surrounding small hyperdynamic right and left ventricles, 11 had localized regions of intense blood pool activity outside the cardiac chambers (two with compression of single chambers), and one demonstrated marked radionuclide activity in the right hemithorax (2000 ml of blood at reoperation). Twelve patients had exploratory reoperation for control of hemorrhage as a direct result of the scintigraphic findings, three were successfully treated with fresh frozen plasma and platelet infusions along with medical interventions to optimize cardiac performance, and two patients died in cardiogenic shock (presumed tamponade) without reoperation. In the 12 reoperated patients, all were confirmed to have active pericardial bleeding. Scintigraphic localization of abnormal blood pools within the pericardium corresponded to the sites at which active bleeding was witnessed at reoperation. The abnormal bleeding was etiologically related to the tamponade state, with marked improvement in hemodynamics after reoperation. Nine additional patients were reoperated for presumed tamponade after RNV revealed an exaggerated halo of photon deficiency surrounding the cardiac chambers. None of these patients were observed to have an active bleeding site at reoperation. Thus, abnormal accumulations of radioactivity surrounding the cardiac chambers should be regarded as specific for the presence of active pericardial or mediastinal bleeding. Repeat imaging 30 minutes to 3 hours after initial imaging, multiple imaging positions, and acquiring RNV in non-zoomed as well as zoomed mode were helpful additions to standard imaging protocols for evaluating early postoperative patients for the presence of significant hemorrhage. From this study, we conclude that the utility of technetium-99m red blood cell RNV in evaluating the etiology of early postoperative cardiogenic shock is enhanced by its ability to detect significant but occult pericardial or mediastinal hemorrhage.     

An esophageal cancer case unresectable due to tuberculous fibrosing mediastinitis: report of a case

We present a case of esophageal carcinoma in which esophagectomy was not possible because of tuberculous fibrosing mediastinitis. A 77-year-old man was diagnosed with carcinoma of the thoracic esophagus and admitted to our hospital. Chest radiography on admission revealed no abnormality except pleural thickening of the pulmonary apices, suggesting a history of subclinical infection of tuberculous pleurisy. The patient underwent surgery with a curative intent. Thoracotomy revealed that the mediastinum had been replaced with dense fibrous tissues and was widely encased with laminar calcification. Esophagectomy was not performed because it was considered impossible to do so safely. Although diagnosis of fibrous mediastinitis was not made preoperatively, review of the preoperative computed tomographic scans revealed proliferation of mediastinal soft tissues that were associated with patchy and laminar calcifications. Tuberculous fibrosing mediastinitis is an uncommon but clinically important disease for physicians who are involved in the diagnosis and treatment of esophageal cancer.     

Pulmonary Hypertension Complicating Fibrosing Mediastinitis

Fibrosing mediastinitis is caused by a proliferation of fibrous tissue in the mediastinum with encasement of mediastinal viscera and compression of mediastinal bronchovascular structures. Pulmonary hypertension (PH) is a severe complication of fibrosing mediastinitis caused by extrinsic compression of the pulmonary arteries and/or veins.We have conducted a retrospective observational study reviewing clinical, functional, hemodynamic, radiological characteristics, and outcome of 27 consecutive cases of PH associated with fibrosing mediastinitis diagnosed between 2003 and 2014 at the French Referral Centre for PH.Fourteen men and 13 women with a median age of 60 years (range 18–84) had PH confirmed on right heart catheterization. The causes of fibrosing mediastinitis were sarcoidosis (n = 13), tuberculosis-infection confirmed or suspected (n = 9), mediastinal irradiation (n = 2), and idiopathic (n = 3). Sixteen patients (59%) were in NYHA functional class III and IV. Right heart catheterization confirmed moderate to severe PH with a median mean pulmonary artery pressure of 42 mm Hg (range 27–90) and a median cardiac index of 2.8 L/min/m² (range 1.6–4.3). Precapillary PH was found in 22 patients, postcapillary PH in 2, and combined postcapillary and precapillary PH in 3. Severe extrinsic compression of pulmonary arteries (>60% reduction in diameter) was evidenced in 2, 8, and 12 patients at the main, lobar, or segmental levels, respectively. Fourteen patients had at least one severe pulmonary venous compression with associated pleural effusion in 6 of them. PAH therapy was initiated in 7 patients and corticosteroid therapy (0.5–1 mg/kg/day) was initiated in 3 patients with sarcoidosis, with 9 other being already on low-dose corticosteroids. At 1-year follow-up, 3 patients had died and among the 21 patients evaluated, 3 deteriorated, 14 were stable, and only 4 patients with sarcoidosis improved (4 receiving corticosteroids and 1 receiving corticosteroids and PAH therapy). Survival was 88%, 73%, and 56% at 1, 3, and 5 years, respectively.We found no clear clinical improvement with the use of specific PAH therapy. Corticosteroid therapy may be associated with clinical improvement, in some patients with fibrosing mediastinitis due to sarcoidosis. Although never performed for this indication, lung transplantation may be proposed in eligible patients with severe PH and fibrosing mediastinitis.     

Incidence and morbidity of cytomegaloviral infection in patients with mediastinitis following cardiac surgery

To determine the incidence and morbidity of infections with CMV associated with mediastinitis after conventional cardiac surgery, 115 consecutive adult patients with mediastinitis were evaluated with viral cultures of blood and urine. Shedding of CMV was seen in 29 patients (25 percent) within a mean period of 37 +/- 22 days after cardiopulmonary bypass. Viremia was documented in 79 percent (23) of these 29 patients. Acute renal failure and enzymatic abnormalities (AST and LDH) were significantly more common in patients with virologically proven infection with CMV (p less than 0.05). In patients who survived the initial period of bacterial infection, major differences in their clinical course were observed according to their virologic status. After the 15th day of hospitalization following the débridement, the persistence of local infection was more frequent (p less than 0.05) and the mortality was higher (p less than 0.01) in CMV-infected patients. Moreover, the mean duration of hospitalization in the ICU for survivors was 69 +/- 36 days in viral shedders, compared with 48 +/- 27 days in nonshedders (p less than 0.05). Infection with CMV in mediastinitis occurs frequently and is associated with persistence of local infection, prolonged hospitalization, and increased late mortality.