A best evidence topic in cardiovascular surgery was written according to a structured protocol. The question addressed was whether patients with severe asymptomatic carotid and coronary artery diseases should undergo simultaneous carotid endarterectomy (CEA) and coronary artery bypass grafting (CABG). A total of 624 papers were found using the reported search, of which 20 represent the best evidence to answer the clinical question. The author, journal, date and country of publication, patient group studied, study type, relevant outcomes, results and study results of these papers are tabulated. Previous cohort studies showed mixed results, while advocating for the necessity of a randomized controlled trial (RCT). A recent RCT showed that patients undergoing prophylactic or simultaneous CEA + CABG had lower rates of stroke (0%) compared with delayed CEA 1-3 months after CABG (7.7%), without significant perioperative mortality difference. This study included patients with unilateral severe (>70%) asymptomatic carotid stenosis requiring CABG. An earlier partly randomized trial also showed better outcomes for patients undergoing simultaneous procedures (P = 0.045). Interestingly, systematic reviews previously failed to show compelling evidence supporting prophylactic CEA. This could be partly due to the fact that these reviews collectively analyse different cohort qualities. Neurological studies have, however, shown reduced cognitive and phonetic quality and function in patients with unilateral and bilateral asymptomatic carotid artery stenosis. Twenty-one RCTs comparing lone carotid artery stenting (CAS) and CEA informed the American Heart Association guidelines, which declared CAS comparable with CEA for symptomatic and asymptomatic carotid stenosis (CS). However, the risk of death/stroke for CAS alone is double that for CEA alone in the acute phase following onset of symptoms, while CEA alone is associated with a doubled risk of myocardial infarction. There is, however, no significant difference for combined 30-day risk of death/stroke/myocardial infarction. Outcomes of hybrid or simultaneous CAS/CABG procedures show comparable results, albeit from rather small cohorts. While current evidence leans towards simultaneous CEA/CABG, the emergence of hybrid operating theatres in various institutions may allow larger cohorts with subsequent significant data on simultaneous CAS/CABG. A randomized controlled trial comparing both approaches would be crucial in informing future updates of existing guidelines.

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was, 'Does severe asymptomatic mitral regurgitation (MR) require surgery or is watch and wait the optimal strategy?'. Over 103 papers were found using the reported search, and 10 represented the best evidence to answer this clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. No studies in the modern era have shown significant survival benefit for patients undergoing surgery for asymptomatic severe MR if they have good left ventricular (LV) function. The progression rate to surgery on developing symptoms is 10% per year in these patients. Ling et al. reported a 63% incidence of congestive heart failure and 30% incidence of chronic atrial fibrillation (AF) at 10 years for conservative treatment, during which period 90% either underwent surgery or died. In addition, one study of 478 patients with good LV operated on in the 1980s showed a 76% 10-year survival in patients who were NYHA I/II but only a 48% 10-year survival in patients with NYHA III/IV although this group was older and had more AF. Early surgery has very good peri- and postoperative survival rates, and the American Heart Association currently recommend that these patients may be operated on if the chance of repair is >90%. Patients may, therefore, be reassured that either strategy is acceptable.

Emergency surgery with valve replacement is the preferred treatment for prosthetic heart valve obstruction (PHVO), with a reported perioperative mortality of up to 17.5% in patients with New York Heart Association (NYHA) class IV before surgery.We followed up 11 patients who had thrombectomy between 1994 and 2004 for the treatment of PHVO (nine thrombi involving mitral and two thrombi involving aortic prosthetic valves). All patients were in NYHA classes III and IV. Immediate surgery was indicated for clinical presentations that included pulmonary edema, low cardiac output, congestive heart failure, and embolism. In all cases, the cause for PHVO was inadequate anticoagulation. None of the patients had underlying clotting disorders.Operations were performed using standard cardiopulmonary bypass with ante-and retrograde cold blood cardioplegia. Both sides of the obstructed valves were inspected. The left atrium was opened in cases involving the aortic, and aortotomy was performed in cases involving the mitral prosthetic valves. The thrombi were removed and the heart cavities rinsed with saline. The lower surfaces of the valves were then inspected with a cardioscope (Storz, Tuttlingen, Germany) to ensure that there were no residual thrombi.Early mortality occurred in one of 11 patients. An 80-year-old patient in NYHA IV with multiple morbidities died on the first postoperative day after mitral prosthetic valve thrombectomy. The cause of death was multiorgan failure. The surviving patients and their physicians were interviewed by telephone with a standardized questionnaire. The mean follow-up time was three years. All survivors were in NYHA class I or II at time of follow-up, and were sufficiently anticoagulated with warfarin. None of the patients required repeat surgery following thrombectomy.In our opinion PHVO does not necessarily require valve replacement. Thrombectomy without valve replacement reduces bypass time, thereby decreasing mortality. It should be considered when managing PHVO, especially for patients in higher NYHAclassification. Awareness of clinical consequences due to insufficient anticoagulation is extremely vital amongst physicians. Figure 1. Thrombosed mechanical mitral valve in situ.

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