in which to connect the conduit vessel that bypasses the blockage; in the u.s., most conduit vessels are harvested endoscopically, using a technique known as endoscopic vessel harvesting (evh). some researchers believe that the off-pump approach results in fewer post-operative complications, such as postperfusion syndrome, and better overall results. study results are controversial as of 2007, the surgeon's preference and hospital results still play a major role. minimally invasive surgery a new form of heart surgery that has grown in popularity is robot-assisted heart surgery. this is where a machine is used to perform surgery while being controlled by the heart surgeon. the main advantage to this is the size of the incision made in the patient. instead of an incision being at least big enough for the surgeon to put his hands inside, it does not have to be bigger than 3 small holes for the robot's much smaller "hands" to get through. pediatric cardiovascular surgery pediatric cardiovascular surgery is surgery of the heart of children. the first operations to repair cardio-vascular defects in children were performed by clarence crafoord in sweden when he repaired coarctation of the aorta in a 12-year-old boy. the first attempts to palliate congenital heart disease were performed by alfred blalock with the assistance of william longmire, denton cooley, and blalock's experienced technician, vivien thomas in 1944 at johns hopkins hospital. techniques for repair of congenital heart defects without the use of a bypass machine were developed in the late 1940s and early 1950s. among them was an open repair of an atrial septal defect using hypothermia, inflow occlusion and direct vision in a 5-year-old child performed in 1952 by lewis and tauffe. c. walter lillihei used cross-circulation between a boy and his father to maintain perfusion while performing a direct repair of a ventricular septal defect in a 4-year-old child in 1954. he continued to use cross-circulation and performed the first corrections of tetralogy of fallot and presented those results in 1955 at the american surgical association. in the long-run, pediatric cardiovascular surgery would rely on the cardiopulmonary bypass machine developed by gibbon and lillehei as noted above. risks of cardiac surgery the development of cardiac surgery and cardiopulmonary bypass techniques has reduced the mortality rates of these surgeries to relatively low ranks. for instance, repairs of congenital heart defects are currently estimated to have 4–6% mortality rates. a major concern with cardiac surgery is the incidence of neurological damage. stroke occurs in 5% of all people undergoing cardiac surgery, and is higher in patients at risk for stroke. a more subtle constellation of neurocognitive deficits attributed to cardiopulmonary bypass is known as postperfusion syndrome, sometimes called "pumphead". the symptoms of postperfusion syndrome were initially felt to be permanent, but were shown to be transient with no permanent neurological impairment. in order to assess the performance of surgical units and individual surgeons, a popular risk model has been created called the euroscore. this takes a number of health factors from a patient and using precalculated logistic regression coefficients attempts to give a percentage chance of survival to discharge. within the uk this euroscore was used to give a breakdown of all the centres for cardiothoracic surgery and to give some indication of whether the units and their individuals surgeons performed within an acceptable range. the results are available on the cqc website. the precise methodology used has however not been published to date nor has the raw data on which the results are based. infection represents the primary non-cardiac complication from cardiothoracic surgery. infections can include mediastinitis, infectious myo- or pericarditis, endocarditis, cardiac device infection, pneumonia, empyema, and bloodstream infections. clostridium difficile colitis can also develop when prophylactic or post-operative antibiotics are used. post operative patients of cardiothoracic surgery are at risk of nausea, vomiting, dysphagia and aspiration pneumonia. thoracic surgery a pleurectomy is a surgical procedure in which part of the pleura is removed. it is sometimes used in the treatment of pneumothorax and mesothelioma. lung volume reduction surgery lung volume reduction surgery, or lvrs, can improve the quality of life for certain patients with copd of emphysematous type, when other treatment options are not enough. parts of the lung that are particularly damaged by emphysema are removed, allowing the remaining, relatively good lung to expand and work more efficiently. the beneficial effects are correlated with the achieved reduction in residual volume. conventional lvrs involves resection of the most severely affected areas of emphysematous, non-bullous lung (aim is for 20–30%). this is a surgical option involving a mini-thoracotomy for patients in end stage copd due to underlying emphysema, and can improve lung elastic recoil as well as diaphragmatic function. the national emphysema treatment trial (nett) was a large multicentre study (n = 1218) comparing lvrs with non-surgical treatment. results suggested that there was no overall survival advantage in the lvrs group, except for mainly upper-lobe emphysema + poor exercise capacity, and significant improvements were seen in exercise capacity in the lvrs group. later studies have shown a wider scope of treatment with better outcomes. possible complications of lvrs include prolonged air leak (mean duration post surgery until all chest tubes removed is 10.9 ± 8.0 days. in people who have a predominantly upper lobe emphysema, lung volume reduction surgery could result in better health status and lung function, though it also increases the risk of early mortality and adverse events. lvrs is used widely in europe, though its application in the united states is mostly experimental. a less invasive treatment is available as a bronchoscopic lung volume reduction procedure. lung cancer surgery not all lung cancers are suitable for surgery. the stage, location and cell type are important limiting factors. in addition, people who are very ill with a poor performance status or who have inadequate pulmonary reserve would be unlikely to survive. even with careful selection, the overall operative death rate is about 4.4%. in non-small cell lung cancer staging, stages ia, ib, iia, and iib are suitable for surgical resection. pulmonary reserve is measured by spirometry. if there is no evidence of undue shortness of breath or diffuse parenchymal lung disease, and the fev1 exceeds 2 litres or 80% of predicted, the person is fit for pneumonectomy. if the fev1 exceeds 1.5 litres, the patient is fit for lobectomy. there is weak evidence to indicate that participation in exercise programs before lung cancer surgery may reduce the risk of complications after surgery. complications a prolonged air leak (pal) can occur in 8–25% of people following lung cancer surgery. this complication delays chest tube removal and is associated with an increased length of hospital stay following a lung resection (lung cancer surgery). the use of surgical sealants may reduce the incidence of prolonged air leaks, however, this intervention alone has not been shown to results in a decreased length of hospital stay following lung cancer surgery. there is no strong evidence to support using non-invasive positive pressure ventilation following lung cancer surgery to reduce pulmonary complications. types lobectomy (removal of a lobe of the lung) sublobar resection (removal of part of lobe of the lung) segmentectomy (removal of an anatomic division of a particular lobe of the lung) pneumonectomy (removal of an entire lung) wedge resection sleeve/bronchoplastic resection (removal of an associated tubular section of the associated main bronchial passage during lobectomy with subsequent reconstruction of the bronchial passage) vats lobectomy (minimally invasive approach to lobectomy that may allow for diminished pain, quicker return to full activity, and diminished hospital costs) esophagectomy (removal of the esophagus)