Mahesh Ramchandani

Lung Myeloid Dendritic Cells Coordinately Induce T H 1 and T H 17 Responses in Human Emphysema

Specialized immune cells in the lungs of patients with emphysema create an inflammatory environment that drives lung destruction in a characteristic autoimmune reaction. Dendritic Cells of Destruction Underlie Emphysema Tobacco smoke is never good for your lungs, and in some people it sets up a destructive process called emphysema. In this disease, air sacs that normally exchange carbon dioxide for oxygen become enlarged, ultimately losing their elastic recoil and physiological function. Breathing becomes labored. Even uninfected lungs with emphysema show signs of a complex immune response, with an accumulation of immune cells. To attack the difficult chicken-or-the-egg problem presented by this disease, Shan et al. sorted out which of these cells serve as the ringleaders in orchestrating this immune reaction and, in the process, found the telltale presence of T helper 17 (TH17) cells—a recently identified hallmark of autoimmune inflammation. Cigarette smoke causes irritation in the lung and activates a general defensive reaction via the innate immune system. When this system cannot restore tissue health, the more precise adaptive immune system comes into play. The authors of Shan et al. now show that specialized professional antigen-presenting cells—called dendritic cells—are recruited by a chemoattractant into the lung, where they induce naïve CD4 T cells to develop into TH1 cells. These immune agents then help cytotoxic T cells to target damaged host lung tissue for destruction. Also induced by the dendritic cells are TH17 cells. These specialized T lymphocytes normally protect the barriers between the body and the environment (the skin and the gut lining, for example), but they also congregate at sites in which the body is erroneously attacking itself, as in autoimmune diseases such as rheumatoid arthritis and colitis. The cytokine interleukin-17A secreted by the TH17 cells coordinates their contribution to destruction of the lung in emphysema by causing lung macrophages to secrete two critical molecules: CCL20, a chemoattractant for the dendritic cells, which then set up an inflammatory positive feedback loop, and matrix metalloproteinase 12 (MMP12), a potent enzyme that destroys a lung endogenous protective proteinase called α1-antitrypsin. In the industrialized world, the ultimate cause of emphysema is usually smoking, but in developing countries, smoke from cooking fires and pollution are important factors in the development of this disease, which is a leading cause of death worldwide. Even after removal of the respiratory irritant, the disease progression is only slowed and existing lung damage is irreversible. Medications can ease the shortness of breath but are not a cure. A lung transplant or partial lung removal is a last resort available only to a few fortunate individuals (see Cypel et al. in this issue). Identification of the cellular players—like the dendritic and TH17 cells described by Shan et al.—through which smoke causes lung destruction is a key to discovering drugs that effect damage control. Moreover, the injurious cellular cycles established in the emphysematous lung are likely not unique, and their elucidation will undoubtedly uncover clues to other immune-related diseases that are associated with smoking. Exposure to tobacco smoke activates innate and adaptive immune responses that in long-term smokers have been linked to diseases of the lungs, cardiovascular system, joints, and other organs. The destruction of lung tissue that underlies smoking-induced emphysema has been associated with T helper 1 cells that recognize the matrix protein elastin. Factors that result in the development of such autoreactive T cells in smokers remain unknown but are crucial for further understanding the pathogenesis of systemic inflammatory diseases in smokers. Here, we show that lung myeloid dendritic cells were sufficient to induce T helper 1 and T helper 17 responses in CD4 T cells. T helper 1 and 17 cells are invariably present in lungs from patients with emphysema but not in lungs from normal individuals. Interleukin-17A, a canonical T helper 17 cytokine, enhanced secretion of CCL20, a chemoattractant for dendritic cells, and matrix metalloproteinase 12, a potent elastolytic proteinase, from lung macrophages. Thus, although diverse lung factors potentially contribute to T helper effector differentiation in vivo, lung myeloid dendritic cells direct the generation of pathogenic T cells and support a feedback mechanism that sustains both inflammatory cell recruitment and lung destruction. This mechanism may underlie disease in other elastin-rich organs and tissues.

Diagnosis and operation for anomalous circumflex coronary artery

BACKGROUND Origin of the left circumflex coronary artery from the right sinus of Valsalva is the most common anatomic variation of the coronary artery circulation. However, there are few reports about the operative approach to this anomalous vessel. METHODS Forty patients having this anomaly were identified from 10,216 adult cardiac catheterization procedures. Forty percent of the anomalous circumflex coronary arteries (ACCAs) had critical atherosclerotic lesions. Eighty cases needed bypass grafting. RESULTS For diagnosis of ACCA, the aortic root sign was positive in 94.9% of the diagnosed patients and the nonperfused myocardium sign was found in 92.5%. Eighty percent of ACCAs were larger than 2 mm in radiographic diameter before their passage into the atrioventricular groove. However, after emerging from the atrioventricular groove, 70% measured less than 1.5 mm. Consequently, a technique was developed to bypass the proximal ACCA and was used in 2 cases. Six other patients with more distal disease and larger vessels underwent conventional bypass grafting. CONCLUSIONS The aortic root sign and nonperfused myocardium are useful in diagnosing ACCA. The ACCA is usually too small for use of the conventional graft technique. Therefore, a technique was developed to graft more proximally and was applied successfully in 2 cases.

Elevated Stroke Risk Associated With Femoral Artery Cannulation During Mitral Valve Surgery

Minimally invasive mitral valve (MV) surgery, often requiring femoral artery (FA) cannulation, is increasingly being adopted. There is concern about increased stroke rates associated with minimally invasive MV surgery. This study aims to examine whether FA cannulation is independently associated with increased stroke rates in minimally invasive MV procedures. MV procedures from January 2004 to June 2012 were reviewed using our institutional Society of Thoracic Surgeons database. We included 384 patients after the exclusion of patients with emergency procedures, with infective endocarditis, who underwent other concomitant procedures, who were older than 60 years, and with nonstandard aortic clamping (endoballoon or no clamp). Patients were divided into 2 groups: those who underwent aortic cannulation (n = 327) and those who underwent femoral cannulation (n = 57). Risk adjustments through multivariable regression were used to identify independent predictors for various outcomes. Adjustments were made for cardiopulmonary bypass and aortic clamp times. Preoperatively, the femoral cannulation group had less baseline cerebrovascular disease (P = 0.032), heart failure (P = 0.028), and atrial fibrillation (P = 0.012). Other baseline characteristics were similar. The aortic cannulation group had shorter cardiopulmonary bypass (P < 0.001) and clamp times (P < 0.001). There were more repairs done in the FA cannulation group as opposed to replacements. Risk-adjusted outcomes showed a higher incidence of permanent stroke in the femoral cannulation group (P = 0.032). Other outcomes were not significantly different. In conclusion, FA cannulation may be associated with increased stroke rates in isolated MV surgery. Antegrade arterial cannulation (direct aortic or axillary cannulation) may be preferable in minimally invasive MV procedures. Randomized trial data are needed.

NECROSIS OF THE ANTEROLATERAL PAPILLARY MUSCLE- AN UNUSUAL MECHANICAL COMPLICATION OF MYOCARDIAL INFARCTION

We report the case of a 66-year-old woman with no significant past medical history who presented to the Emergency Department at Houston Methodist Hospital with 24 hours of chest pain. An electrocardiogram was done, an electrocardiogram confirmed a posterolateral ST elevation myocardial infarction. An immediate and successful percutaneous coronary intervention of a totally occluded ramus intermedius was performed. Six hours later she developed pulmonary edema, cardiogenic shock, severe acidosis, and anuria. Echocardiography showed severe mitral regurgitation due to a ruptured anterolateral papillary muscle, and emergency surgery revealed necrosis of this muscle. A bioprosthetic mitral valve was placed, and extracorporeal membrane oxygenation was needed for 3 days. This is a rare mechanical complication of myocardial infarction, which usually affects the posteromedial papillary muscle. The patient subsequently made a good recovery. One month later, just prior to discharge home, the patient developed pneumonia and sepsis, and she expired from multiorgan failure.

Case Report: Simultaneous Localization and Removal of Lung Nodules Through Extended Use of the Hybrid Suite

The ability to attain high-definition imaging for preoperative planning, intraoperative execution, and postoperative evaluation is instrumental in surgical practice. Hybrid room computed tomography (CT) allows for faster, less invasive diagnostic and therapeutic options for patients. We present our diagnostic workup and therapeutic intervention with hybrid CT imaging in a 71-year-old female with a growing lung nodule after previous lobectomy for lung cancer.

Mucoepidermoid Carcinoma of the Tracheobronchial Tree.

Primary salivary type lung cancers are extremely rare intrathoracic malignancies. Mucoepidermoid tumor is one of the salivary gland tumors that originates from submucosal glands of the tracheobronchial tree. These are very slow-growing low-grade malignant tumors. Surgery is the mainstay of treatment and rarely requires adjuvant therapy. In this case report we describe a 65-year-old woman who presented with a solitary cough yet on further investigation was found to have a mucoepidermoid tumor originating from the hilum of the left lung.

CHRONIC RECURRENT UNILATERAL PULMONARY INFECTION: RESULT OF CONGENITAL UNILATERAL AGENESIS OF PULMONARY ARTERY

Unilateral agenesis of the pulmonary artery (UAPA) is a rare congenital anomaly. This report describes a 52-year-old female who gave a long history of chronic, recurrent, left-sided pulmonary infections related to UAPA. For many years, she was managed medically but the infection continued to recur. She eventually underwent left pneumonectomy and made a good recovery.

Cannulation Strategies and Pitfalls in Minimally Invasive Cardiac Surgery

For any given cardiac surgery, there are two invasive components: the surgical approach and the cardiopulmonary bypass circuit. The standard approach for cardiac surgery is the median sternotomy, which offers unrestricted access to the thoracic organs-the heart, lung, and major vessels. However, it carries a long list of potential complications such as wound infection, brachial plexus palsies, respiratory dysfunction, and an unpleasant-looking scar. The cardiopulmonary bypass component also carries potential complications such as end-organ dysfunction, coagulopathy, hemodilution, bleeding, and blood transfusion requirement. Furthermore, the aortic manipulation during cannulation and cross clamping increases the risk of dissection, arterial embolization, and stroke. Minimally invasive cardiac surgery is an iconic event in the history of cardiothoracic medicine and has become a widely adapted approach as it minimizes many of the inconvenient side effects associated with the median sternotomy and bypass circuit placement. This type of surgery requires the use of novel perfusion strategies, especially in patients who hold the highest potential for postoperative morbidity. Cannulation techniques are a fundamental element in minimally invasive cardiac surgery, and there are numerous cannulation procedures for each type of minimally invasive operation. In this review, we will highlight the strategies and pitfalls associated with a minimally invasive cannulation.

Intraoperative Surgical Sealant Application during Cardiac Defect Repair

Bleeding can occur as a sequela to cardiac surgery. Surgical products-such as conventional sutures and clips, and somewhat less conventional sealants-have been developed to prevent this event. Among these, CoSeal is a sealant used at our institution; here we report the cases of 2 patients in whom CoSeal was used successfully as either a supplement or an alternative to suture repair. This sealant was found to be useful in attaining hemostasis both in high-pressure ventricular repair and in the rupture of a friable coronary sinus adjacent to vital structures (in this instance, a left circumflex coronary artery).

Surgical Approaches to Aortic Valve Replacement and Repair—Insights and Challenges

Since 1960, surgical aortic valve replacement (sAVR) had been the only effective treatment for symptomatic severe aortic stenosis until the recent development of transcatheter aortic valve replacement (TAVR). TAVR has offered an alternative, minimally invasive treatment approach particularly for patients whose age or co-morbidities make them unsuitable for sAVR. The rapid and enthusiastic utilization of this new technique has triggered some speculation about the imminent demise of sAVR. We believe that despite the recent advances in TAVR, surgical approach to aortic valve replacement has continued to develop and will continue to be highly relevant in the future. This article will discuss the recent developments and current approaches for sAVR, and how these approaches will keep pace with catheter-based technologies.