Does muscle-sparing thoracotomy as opposed to posterolateral thoracotomy result in better recovery?

A best evidence topic was written according to a structured protocol. The question addressed was whether muscle-sparing thoracotomy (MST), as opposed to posterolateral thoracotomy (PLT), results in better recovery. A total of 108 papers were found using the reported searches of which eight represented the best evidence to answer the clinical question. The authors, date, journal, study type, population, main outcome measures and results are tabulated. A recent large prospective, randomized, double-blinded, controlled study demonstrated a shorter length of stay in patients undergoing MST. It failed to demonstrate any significant difference in pain reported or pulmonary function. A separate prospective randomized controlled trial focussed on pain, pulmonary function, late shoulder range of motion and late muscle strength. It failed to show any significant difference in these domains between PLT and MST. While the mean 'opening time' is greater when performing a MST, this is negated by a shorter mean 'closing time' when compared with PLT. Overall, the evidence suggests that MST results in greater early (1 week) preservation of skeletal muscle strength and range of motion over PLT. This difference has disappeared at 1 month. There is little evidence to suggest a difference in pulmonary function or pain dependent on the thoracotomy type. Moreover, analgesic consumption is similar. However, there is an inverse relationship between the incision length and the post-thoracotomy syndrome.

Does surgery improve prognosis in patients with small-cell lung carcinoma?

A best evidence topic was written according to a structured protocol, asking 'does surgery improve prognosis in patients with small-cell lung carcinoma (SCLC)?' One hundred and thirteen papers were identified, of which the nine papers best able to answer the question were selected and the details of each tabulated. The prohibitive attitude of clinicians toward surgery in SCLC has prevailed since the 1960s, informed by a prospective randomized trial in which 144 patients were assigned to surgical treatment or to radical radiotherapy. Surgery conferred no survival benefit when compared with radical radiotherapy as assessed at 6 monthly intervals up to 10 years post-treatment. Patients with metastatic disease were excluded; however, diagnostic advances subsequent to these trials justify a re-evaluation of the issue, given the greater degree of accuracy with which sub-groups of patients who might benefit from surgery can now be defined. Only one further prospective, randomized trial features in the literature. This study also discerned that no survival benefit was accrued by adding surgery to chemotherapy. However, this study only included patients who responded to an initial course of chemotherapy and also excluded patients with peripheral nodules only. Subsequent investigators have asserted the value of surgery in SCLC. A retrospective case-control study found that surgery significantly improved median survival in patients with stage I disease when compared with patients undergoing medical therapy. One British centre reported survival rates of 52% at 5 years amongst patients undergoing resection and nodal dissection for stage II-IIIA disease. In a retrospective analysis of the Norwegian cancer database, 5-year survival for patients with stage I undergoing surgery was 44.9%, as opposed to 11.3% amongst those treated medically. This finding was echoed in the analysis of the surveillance epidemiology and end results database in the USA, which found improved median survival amongst patients undergoing surgery for limited SCLC. Prospective studies of carefully selected patients have documented good median survival in patients whose tumour was completely resected. We conclude that surgery for early-stage SCLC improves prognosis as part of a multi-modality approach. This echoes the advice of the 2011 national institute of health and clinical excellence guidelines regarding surgery in SCLC.

Can pregnant women be safely placed on cardiopulmonary bypass?

A best evidence topic was written according to a structured protocol. The question addressed was whether cardiopulmonary bypass can be used safely with satisfactory maternal and foetal outcomes in pregnant patients undergoing cardiac surgery. A total of 679 papers were found using the reported searches of which 14 represented the best evidence to answer the clinical question. The authors, date, journal, study type, population, main outcome measures and results are tabulated. Reported measures were maternal and foetal mortality and complications, mode of delivery, cardiopulmonary bypass and aortic cross-clamp times, perfusate flow rate and temperature and maternal NYHA functional class. The most recent of the best evidence studies, a retrospective observational study of 21 pregnant patients reported early and late maternal mortalities of 4.8 and 14.3%, respectively, and a foetal mortality of 14.3%. Median cardiopulmonary bypass and aortic cross-clamp times were 53 and 35 min, respectively, and the median bypass temperature was 37°C. Three larger retrospective reviews of the literature reported maternal mortality rates of 2.9-5.1% and foetal mortality rates of 19-29%. Mean cardiopulmonary bypass times ranged from 50.5 to 77.8 min. Another retrospective observational study reported maternal mortality of 13.3% and foetal mortality of 38.5%. Mean cardiopulmonary bypass and aortic cross-clamp times were 89.1 and 62.8 min, respectively, with a mean bypass temperature of 31.8°C. A retrospective case series reported no maternal mortality and one case of foetal mortality. Median cardiopulmonary bypass and aortic cross-clamp times were 101 and 88 min, respectively. Eight case reports described 10 patients undergoing cardiopulmonary bypass. There were no reports of maternal mortality and one report of foetal mortality. Mean cardiopulmonary bypass and aortic cross-clamp times were 105 and 50 min, respectively. We conclude that while the use of cardiopulmonary bypass during pregnancy poses a high risk for both the mother and the foetus, the use of high-flow, high-pressure, pulsatile, normothermic bypass and continuous foetal and uterine monitoring can allow cardiac surgery with the use of cardiopulmonary bypass to be performed with the greatest control of risk in the pregnant patient.

Is there benefit in smoking cessation prior to cardiac surgery?

A best evidence topic was written according to a structured protocol. The question addressed was whether smoking cessation prior to cardiac surgery would result in a greater freedom from postoperative complications. A total of 564 papers were found using the reported searches, of which five represented the best evidence to answer the clinical question. The authors, date, journal, study type, population, main outcome measures and results are tabulated. Reported measures were operative mortality, pulmonary complications, infective complications, neurological complications, transfusion requirements, duration of ventilation, intensive care unit and hospital stay, intensive care unit re-admission, postoperative gas exchange parameters and postoperative pulmonary function. The largest of the best evidence studies demonstrated a significant reduction in pulmonary complications in non-smokers (P < 0.001); however, there was an increased requirement for transfusion in this cohort (P = 0.002). There were non-significant reductions in neurological complications, infective complications and re-admissions to intensive care. Another large cohort study demonstrated significant reductions in non-smokers in mortality (P < 0.0001), pulmonary complications (P = 0.0002), infection (P < 0.0007), intensive care unit re-admission (P = 0.0002), duration of mechanical ventilation (P = 0.026) and intensive care unit stay (P = 0.002). A larger cohort study again demonstrated significant reductions in non-smokers in pulmonary complications (P < 0.002), duration of mechanical ventilation (P < 0.012) and intensive care unit stay (P < 0.005). A smaller prospective cohort study reported significantly raised PaO(2) (P = 0.0091) and reduced PaCO(2) (P < 0.0001) levels in the non-smokers as well as improved FVC and FEV(1) (P < 0.0001). There were also reductions in duration of intubation (P < 0.0001), intensive care unit stay (P < 0.0001) and hospital stay (P < 0.0013). Another small cohort study reporting outcomes of heart transplantation demonstrated significant improvement in non-smokers in terms of survival (P = 0.031), duration of intubation (P = 0.05) and intensive care unit stay (P = 0.021). We conclude that there is strong evidence demonstrating superior outcomes in non-smokers following cardiac surgery and advocate the necessity of smoking cessation as soon as possible prior to cardiac surgery.

Is there a suitable method of anticoagulation in pregnant patients with mechanical prosthetic heart valves?

A best evidence topic was written according to a structured protocol in order to identify the mode of anticoagulation that has the best safety profile for both the mother and the foetus in pregnant patients with mechanical prosthetic heart valves. A total of 281 papers were identified using the reported search, of which eight represented the best evidence to answer the clinical question. The authors, date, journal, study type, population, main outcome measures and results are tabulated. The reported measures were foetal mortality, maternal mortality, congenital abnormalities and embryopathy, and maternal thromboembolic and haemorrhagic complications. The medical orthodoxy has warned of the combination of oral anticoagulation and pregnancy due to the well-documented warfarin embryopathy. Yet only one of the reported papers identified a greater incidence of foetal aberrations among warfarin use, with the highest reported rate being 6.4% and two of the assessed papers reporting no embryopathy at all. Foetal mortality with oral anticoagulation use ranged from 1.52 to 76%. All reported publications demonstrated a superior maternal outcome with warfarin use, with a range of thromboembolic events from 0 to 10% in comparison with 4 to 48% where heparin was used. Thus, it is concluded that warfarin is a more durable anticoagulant with a better maternal outcome despite it carrying a greater foetal risk. Although, in contrast to previous teaching, the risks of embryopathy are not the major drawback of oral anticoagulation. Heparin is consistently less effective, but may be preferred for the superior foetal outcome. Heparin usage during the first trimester reduces the foetal risk but is still associated with an adverse maternal outcome. While the focus for clinicians looking after pregnant women with mechanical heart valves may be to prevent maternal thromboembolic complications, the overriding concern for many women is to avoid any harm to their unborn child, even when this places their health at risk. Thus women with mechanical heart valves must be fully informed of the risks involved with different anticoagulation for an informed decision to be made.

Is heparin needed for patients with an intra-aortic balloon pump?

We addressed the question of whether or not the currently available evidence base supports heparinization in the context of a patient requiring cardiovascular support with an intra-aortic balloon pump (IABP). A best evidence topic was written according to a previously defined structured protocol. A literature search returned 443 papers, 3 of which were deemed relevant. Jiang et al. randomized 153 patients requiring IABP to heparin or no heparin, matched for age, sex and comorbidities. There was no significant difference in limb ischaemia; however, incidence of bleeding was significantly increased in the heparinized group (14.1 vs 2.4%). One cohort study compared two management strategies of IABP in which patients either received heparin universally or selectively with heparin only given for certain pre-defined indications. They reported increased bleeding with universal heparinization (39.2 vs 31.8%) but similar other complication rates. Another cohort study in which patients with IABP were initially treated with glycoprotein IIb/IIIa antagonists only, reported bleeding and ischaemia rates within accepted ranges for heparinized patients. The use of anticoagulation with IABP is intended to reduce the risk of thrombus, thromboembolus or limb ischaemia whilst generating an increased risk of bleeding as a side-effect. The aforementioned studies demonstrate that omitting or implementing a selective use strategy of heparinization during IABP counterpulsation can significantly decrease the incidence of bleeding without an increase in ischaemic events. One study also performed angiography prior to IABP insertion on some of their patients, selecting the less diseased side to insert the IABP. Current evidence on this topic is sparse, especially as relates to patients in the context of cardiothoracic surgery. Just one study specifically looked at surgical patients. However, the existing data suggest that it is safe to omit heparinization when using IABP counterpulsation. The decision to heparinize should be weighed in the context of other indications or contraindications rather than being an automatic response to the use of IABP.

Are intracostal sutures better than pericostal sutures for closing a thoracotomy?

A best evidence topic was written according to a structured protocol. The question addressed was to identify which thoracotomy closure method lends itself to the least postoperative pain. Altogether 109 papers were found using the reported search; of which, seven represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. We conclude that the closure by intracostal sutures with intercostal nerve sparing offers a superior postoperative pain profile for thoracotomy patients when compared with conventional techniques. Up to 1-year follow-up has shown that this technique (avoiding strangulation of the intercostal nerve) leads to lower postoperative pain and analgesic use, better ambulation and a quicker return to daily activities. Three papers (including two randomized trials) found intracostal sutures with intercostal nerve sparing techniques to be superior to conventional methods such as pericostal suture closure. Rib approximation with intercostal nerve sparing was found to be superior to rib approximation without nerve sparing in one study. Two studies associated with the creation of an intercostal muscle flap prior to the insertion of a rib retractor to be associated with significantly reduced postoperative pain. One study described a novel 'edge-closure' technique, comparable to the closure with intracostal sutures without drilling, to be superior to conventional closure with pericostal sutures. Postoperative pain is a significant issue faced by thoracic surgeons both in-hospital and in the longer term where patients may complain of chronic thoracotomy pain. We would therefore recommend that some form of intercostal nerve protection be implemented during thoracotomy opening and closure.

Does posterior pericardiotomy reduce the incidence of atrial fibrillation after coronary artery bypass grafting surgery?

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was whether posterior pericardiotomy (PP) reduces the incidence of atrial fibrillation (AF) after coronary artery bypass grafting surgery. Twelve papers were found using the reported search, of which seven represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers were tabulated. One non-randomized prospective cohort controlled study generated early evidence that PP reduced the rate of postoperative AF and pericardial effusion. The operative details of PP were clearly explained in this paper. The efficacy of this procedure was subsequently examined in five prospective randomized controlled trials performed with some limitations, listed in the table. Meta-analysis of the randomized control trials examined a group of 763 patients (PP = 389, control = 374). It revealed a highly significant reduction in total arrhythmias and AF in the PP group (odds ratio 0.31 and 0.33, respectively). There was a 10.8% AF rate in the PP group (41/379) and a 28.1% AF rate in the control group (108/384). Furthermore, the PP group had a significant reduction in the rate of early and late pericardial effusion (P < 0.001). Moreover, the reduction in the incidence of arrhythmias was significantly associated with the reduction in the incidence of pericardial effusion. Referring to these studies, two guidelines recommend PP to reduce postoperative AF with grade B strength of recommendation. We conclude that PP significantly reduces the incidence of postoperative AF. The number needed to treat to prevent one case of AF is six.

Does video-assisted mediastinoscopy have a better lymph node yield and safety profile than conventional mediastinoscopy?

A best evidence topic was written according to a structured protocol. The question addressed was whether video-assisted mediastinoscopy (VAM) has a better lymph node yield and safety profile than the conventional mediastinoscopy (CM). A total of 194 papers were found, using the reported searches, of which five represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. Two studies to date have directly compared CM and VAM with respect to lymph node yield, calculated diagnostics performance and complication rate. In both of these, lymph node yield is shown to be higher using VAM with better sensitivity, negative predictive value and accuracy rates. The favourable figures of lymph node sampling are found to be statistically significant in the single study providing such analysis. Complication rates using VAM are low, however, in the one instance where it is reported as higher than CM, the extensive lymph node dissection used in this technique may be a reasonable explanation for this finding. All studies described here exemplify VAM as a safe and useful tool in mediastinal staging, lymph node dissection and tissue diagnosis of mediastinal diseases given its superior visualization of surrounding structures and advantage of bimanual dissection. The future scope for diagnostic and therapeutic indications of cervical mediastinscopy is anticipated with recent advances and new techniques, such as video-assisted mediastinoscopic lymphadenectomy and virtual mediastinscopy.

Does a 'no-touch' technique result in better vein patency?

A best evidence topic was written according to a structured protocol. The question addressed was whether harvesting the saphenous vein (SV) as a conduit for coronary artery bypass grafting (CABG) using a no-touch technique would result in better patency rates. This technique involves the harvest of the SV with a pedicle of peri-vascular tissue left intact and the avoidance of distension of the vein prior to anastomosis. A total of 405 papers were found using the reported searches of which eight represented the best evidence to answer the clinical question. The authors, date, journal, study type, population, main outcome measures and results are tabulated. The studies found analysed the ultrastructural and mechanical properties of the endothelium and vessel walls of the two harvesting techniques; the protein and enzymatic expression and activity observed; the early atherosclerotic changes detected; and the overall patency of the grafts during short- and long-term angiographical follow-up. Three small prospectively randomised studies compared the patency of grafts harvested using the two techniques and found significant improvements in graft patency using the no-touch harvesting technique in comparison to both the conventional technique and more importantly comparable to the left internal thoracic artery (LITA) patency. The most favourable difference was that of graft patency after 8.5 years of follow-up [90% vs. 76% (P = 0.01), LITA patency 90%], and incidence of graft stenosis [11% vs. 25% (P = 0.006)]. These findings were supported by the demonstrated improvements in the cellular integrity of the vessels and the reduction in the mechanisms leading to graft failure seen in the no-touch harvested SV grafts. These morphological and cellular analyses were carried by five small comparative studies, demonstrating improved endothelial integrity and reduced injury, decelerated atherosclerotic processes, intact adventitial collagen layers, increase in the total area of vasa vasorum, elevated endothelial nitric oxide synthase expression and activity, and increased peri-vascular leptin levels and activity. We conclude that there are clear enhancements in vessel wall properties at a cellular level and angiographical evidence of superior graft patency when the no-touch SV harvesting technique is employed.

Is it safe to perform coronary angiography during acute endocarditis?

A best evidence topic was written according to a structured protocol. The question addressed was 'Is it safe to perform coronary angiography (CA) in acute endocarditis?' Three hundred and ninety-seven papers were found using the reported search, of which six represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes, key results and limitations of these papers are tabulated. One of the papers is a case report, which reported a fatal vegetation embolism from an infected aortic valve into the left main coronary artery 14 h after angiography. The remaining five papers are cohort studies. Four of these studies were performed between 1970 and 1980 before the era of echocardiography and were aimed at quantifying the severity of valvular regurgitation. No embolic complications or dislodgement of vegetations occurred in any of the five studies (186 patients). Guidelines published by the European Society of Cardiology (ESC) in 2009 recommended CA in the context of infective endocarditis (IE) for men >40 years old, postmenopausal women, and patients with at least one cardiovascular risk factor or a history of coronary artery disease. Exceptions include patients with large aortic vegetations which may be dislodged during catheterisation, and when emergency surgery is necessary - 1) native aortic or mitral IE with severe acute regurgitation or valve obstruction, or prosthetic valve IE with severe prosthetic dysfunction (dehiscence or obstruction) causing refractory pulmonary oedema or cardiogenic shock; 2) native aortic, mitral, or prosthetic valve IE with fistula into a cardiac chamber or pericardium causing refractory pulmonary oedema or shock. This is reiterated by the guidelines on the management of valvular heart disease published by the ESC in 2007. From the findings of the six papers, it can be concluded that coronary angiography can be performed safely in IE and should be performed if deemed necessary, unless the patients are haemodynamically unstable requiring emergency surgery, or have large vegetations of the aortic valve. This is consistent with the ESC guidelines.

Does the nerve of Kuntz exist?

A best evidence topic was written according to a structured protocol. The question addressed was, in what proportion of patients is the nerve of Kuntz identifiable? A total of 55 papers were found using the reported search, of which six represented the best evidence to answer the clinical question. The authors, date, journal, study type, population, main outcome measures and results are tabulated. The nerve of Kuntz was originally described in 1927 as being a connection from the second intercostal nerve to the first thoracic ventral ramus. Controversy exists as to whether it is present universally and thus whether it should be identified during thoracoscopic sympathectomy. The six studies highlighted involved dissection of the upper thoracic sympathetic chain of adult cadavers with descriptions of the anatomical variations. A study by Cho et al. [Cho HM, Lee DY, Sung SW. Anatomical variations of rami communicants in the upper thoracic sympathetic trunk. Eur J Cardiothorac Surg 2005;27:320-324] suggested that anatomical variation was more common at T2 compared to T3 and T4, of which 60% corresponded to the original description of the nerve of Kuntz. A similar prevalence was found by Marhold and colleagues [Marhold F, Izay B, Zacherl J, Tschabitscher M, Neumayer C. Thoracoscopic and anatomic landmarks of Kuntz's nerve: implications for sympathetic surgery. Ann Thorac Surg 2008;86:1653-1658], who also suggested that open dissection led to significantly easier identification of this anatomy than thoracoscopy. The same authors frequently found that the nerve of Kuntz was associated with a superior intercostal vein located parallel to it, meaning that these subpleural veins may act as an anatomical landmark. In four of the papers where cadavers where dissected bilaterally, variations in the anatomy of the sympathetic chain were not always symmetrical. We conclude that most patients will have some form of variation in the anatomy of their T2 ganglion, which often corresponds to the original description of the nerve of Kuntz. The appreciation of this variation may be more difficult during thoracoscopy as compared to open anatomic dissection.

Should surgeons scrub with chlorhexidine or iodine prior to surgery?

A best evidence topic was written according to a structured protocol. The question addressed was whether chlorhexidine gluconate is equivalent or superior to the use of povidone-iodine during surgical hand scrub. A total of 593 papers were found using the reported searches of which eight represented the best evidence to answer the clinical question. The authors, date, journal, study type, population, main outcome measures and results are tabulated. We conclude that whilst both chlorhexidine and povidone-iodine reduce bacterial count after scrubbing, the effect of chlorhexidine is both more profound and longer lasting. The studies found analysed the difference in reduction in colony forming units or bacterial count following surgical scrub in order to conclude that chlorhexidine was superior. Four studies went further to analyse cumulative and residual activity by testing for bacterial reduction after using a scrub solution for a number of days, an area in which chlorhexidine showed consistent advantages over povidone-iodine. These findings are given more credibility by the clinical finding of a recent meta-analysis of over 5000 patients in which chlorhexidine as an antiseptic skin preparation was associated with significantly reduced surgical site infection (SSI) in clean-contaminated surgery. Despite this, there is no evidence suggesting the use of chlorhexidine during hand scrub reduces SSI, which perhaps explains why guidelines from the World Health Organization, the Centers for Disease Control and Prevention and the Association for Perioperative Practice do not recommend one specific antimicrobial over another for hand scrub.

Should a patent foramen ovale found incidentally during isolated coronary surgery be closed?

A best evidence topic was written according to a structured protocol. The question addressed was whether incidentally found patent foramen ovale (PFO) during isolated coronary surgery should be closed. A total of 573 papers were found using the reported searches of which six represented the best evidence to answer the clinical question. The authors, date, journal, study type, population, main outcome measures and results are tabulated. There is currently no evidence to suggest that incidental PFO in patients undergoing cardiac surgery is linked with increased morbidity, mortality or decreased long-term survival. The most significant study identified examined the outcomes of 2277 patients with incidentally found PFO during cardiac surgery of whom 639 underwent closure. After propensity matched analysis, the authors found closure was associated with a significantly higher risk of postoperative stroke with no advantage in terms of long-term survival. A recent survey of 438 cardiac surgeons from the USA showed no consensus on decision-making behind closure, but that factors taken in to account include PFO size, right atrial pressure and a history of paradoxical embolism. This is not surprising given that morphological research has confirmed that larger PFO size is indeed associated with cryptogenic stroke.