The mitral valve in hypertrophic cardiomyopathy.

PURPOSE OF REVIEW: Whilst abnormally increased left ventricular wall thickness is the hallmark feature of hypertrophic cardiomyopathy (HCM), anomalies of the mitral valve and supporting apparatus are well documented. This review addresses the clinical importance of mitral valve abnormalities in HCM, their mechanistic associations with symptoms, and therapeutic strategies targeting mitral valve and apparatus abnormalities. RECENT FINDINGS: The normal mitral valve possesses anatomical features facilitating unrestricted blood flow during LV filling, preventing regurgitation during LV systole, and avoiding obstruction of LV ejection. In HCM, a variety of structural and functional abnormalities can conspire to cause deranged mitral valve function, with implications for management strategy. Identification and characterization of these abnormalities is facilitated by multimodality imaging. Alcohol septal ablation (ASA) cannot address primary mitral valve abnormalities, and so is not preferred to surgical intervention if mitral valve abnormalities are present and are judged to make dominant contributions to LV outflow tract obstruction (LVOTO). Two broadly opposing surgical intervention strategies exist, one advocating isolated septal myectomy and the other including adjuvant mitral apparatus modification. Newer, less invasive surgical and transcatheter techniques will expand interventional options. SUMMARY: Mitral valve abnormalities are a central pathological feature of HCM. Multimodality imaging is crucial for their identification and characterization prior to therapeutic intervention.

Obesity and diabetes are major risk factors for epicardial adipose tissue inflammation.

BACKGROUNDEpicardial adipose tissue (EAT) directly overlies the myocardium, with changes in its morphology and volume associated with myriad cardiovascular and metabolic diseases. However, EAT's immune structure and cellular characterization remain incompletely described. We aimed to define the immune phenotype of EAT in humans and compare such profiles across lean, obese, and diabetic patients.METHODSWe recruited 152 patients undergoing open-chest coronary artery bypass grafting (CABG), valve repair/replacement (VR) surgery, or combined CABG/VR. Patients' clinical and biochemical data and EAT, subcutaneous adipose tissue (SAT), and preoperative blood samples were collected. Immune cell profiling was evaluated by flow cytometry and complemented by gene expression studies of immune mediators. Bulk RNA-Seq was performed in EAT across metabolic profiles to assess whole-transcriptome changes observed in lean, obese, and diabetic groups.RESULTSFlow cytometry analysis demonstrated EAT was highly enriched in adaptive immune (T and B) cells. Although overweight/obese and diabetic patients had similar EAT cellular profiles to lean control patients, the EAT exhibited significantly (P ≤ 0.01) raised expression of immune mediators, including IL-1, IL-6, TNF-α, and IFN-γ. These changes were not observed in SAT or blood. Neither underlying coronary artery disease nor the presence of hypertension significantly altered the immune profiles observed. Bulk RNA-Seq demonstrated significant alterations in metabolic and inflammatory pathways in the EAT of overweight/obese patients compared with lean controls.CONCLUSIONAdaptive immune cells are the predominant immune cell constituent in human EAT and SAT. The presence of underlying cardiometabolic conditions, specifically obesity and diabetes, rather than cardiac disease phenotype appears to alter the inflammatory profile of EAT. Obese states markedly alter EAT metabolic and inflammatory signaling genes, underlining the impact of obesity on the EAT transcriptome profile.FUNDINGBarts Charity MGU0413, Abbott, Medical Research Council MR/T008059/1, and British Heart Foundation FS/13/49/30421 and PG/16/79/32419.

Predicting cardiac surgical site infection: development and validation of the Barts Surgical Infection Risk tool.

OBJECTIVES: The objective of this study was to develop and validate a new risk tool (Barts Surgical Infection Risk (B-SIR)) to predict surgical site infection (SSI) risk after all types of adult cardiac surgery, and compare its predictive ability against existing (but procedure-specific) tools: Brompton-Harefield Infection Score (BHIS), Australian Clinical Risk Index (ACRI), National Nosocomial Infection Surveillance (NNIS). STUDY DESIGN AND SETTING: Single-center retrospective analysis of prospectively collected data including 2,449 patients undergoing cardiac surgery between January 2016 and December 2017 in a European tertiary hospital. Thirty-four variables associated with SSI risk after cardiac surgery were collated from three local databases. Independent predictors were identified using stepwise multivariable logistic regression. Bootstrap resampling was conducted to validate the model. Hosmer-Lemeshow goodness-of-fit test was performed to assess calibration of scores. RESULTS: The B-SIR model was constructed from six independent predictors female gender, body mass index >30, diabetes, left ventricular ejection fraction <45%, peripheral vascular disease and operation type, and the risk estimates were derived. The receiver operating characteristics curve for B-SIR was 0.682, vs. 0.603 for BHIS, 0.618 for ACRI, and 0.482 for the NNIS tool. CONCLUSION: B-SIR provides greater predictive power of SSI risk after cardiac surgery compared with existing tools in our population.

A prospective five-year cohort study of undiagnosed sleep apnea in patients undergoing coronary artery bypass graft surgery.

BACKGROUND: We aimed to study prospectively the nature and effect of sleep apnea-hypopnea syndrome (SAHS) in patients undergoing coronary artery bypass graft (CABG) surgery over five years of follow-up. METHODS: Patients undergoing CABG surgery (N.=145) were assessed longitudinally (baseline, 1 year, and 5 years post-surgery) using the 'STOP-BANG' screen of sleep apnea risk. Additionally, all patients had a preoperative multiple-channel sleep-study, providing acceptable data for an obstructive and central apnea, and desaturation index in 97 patients. RESULTS: Preoperatively, over half (63%) of patients obtained an apnea-hypopnea index score (combining apnea types) in the moderate-severe range for SAHS, and STOP-BANG threshold score (>3/8) was reached by most (95%) patients. Despite some improvement in 'STOP symptoms' at 1-year follow-up, most patients (98%) remained at risk of SAHS at 5 years post-surgery. There was an underlying and chronic relationship between STOP-BANG score and cardiac symptoms at both baseline and 5-year follow-up. Additionally, SAHS variables were associated with greater incidence of acute postoperative events, and generally with increased length of stay on the intensive care unit. CONCLUSIONS: We confirm that SAHS is common in CABG-surgery patients, presenting additional clinical challenges and cost implications. The underlying pathophysiology is complex, including upper airway obstruction and cardiorespiratory changes of heart failure. In patients presenting for CABG-surgery, we show chronic susceptibility to SAHS, likely associated with traditional risk factors e.g. obesity but perhaps also with gradual decline in heart function itself. Superimposed on this, there is potential for exacerbated risk of morbidity at the time of CABG surgery itself.

Is there a role for biomarkers in thoracic aortic aneurysm disease?

Thoracic aortic aneurysm (TAA) represents a major cause of mortality and morbidity in Western countries. The natural history of TAA is indolent, with patients usually being asymptomatic until a catastrophic event such as rupture or dissection ensues. As such, early diagnosis is crucial and the search is ongoing for a biomarker that can indicate the presence of TAA with sufficient accuracy to act as a screening tool. To date, no such marker has been developed for the diagnosis of non-familial or 'sporadic' TAA. However, our increased understanding of the pathogenesis of both familial and sporadic TAA has suggested potential candidates for diagnostic biomarkers. Many markers/pathways have been shown to have differential activity levels or expression in the aortic tissue of TAA. However, priority is given to markers that have shown differential levels in blood plasma, as blood tests represent the easiest route for mass screening for TAA. This review aims to evaluate the efficacy of clinical tests already in use in diagnosing TAA, explore novel proposed biomarkers and identify key areas of future interest.

The sternal wire code; Solving the problem of missing coronary artery bypass graft records during cardiac catheterization.

BACKGROUND: The sternal wire code records details of coronary artery bypass surgery (CABG) inside patients, based on the orientation of wires used for sternal closure. Visible on X-ray, the code overcomes the problem of missing graft-notes needed before repeat angiography. We determined (i) the potential value (ii) acceptability and (iii) accuracy of the code in practice. METHODS: (i) Consecutive coronary angiogram reports (2015-2016 Barts, London) were reviewed to identify patients with previous CABG and those with and without graft-notes before angiography. (ii) UK surgeons were surveyed on whether they would insert the code during CABG. (iii) A clinician, blinded to operative details, interpreted 16 post-CABG X-rays, 8 with the code and 8 without. RESULTS: (i) Of 6483 angiography patients, 559 had previous CABG (9.2% (8.5-10%)). Graft-notes were missing in 91/559 (15.1% (12-18%)); almost all (88/91) among patients with acute myocardial infarction. (ii) In the survey, 66/71surgeons (93% (84-98%)) were willing to use the code. (iii) In the accuracy test, all coded X-rays were identified and 28/28 grafts correctly interpreted (p < 0.001). CONCLUSIONS: About 1 in 6 patients with previous CABG, who require emergency coronary angiography, undergo this procedure without graft-notes and would benefit from the sternal wire code which appears clinically acceptable and accurate.

Aortic Valve Replacement: Are We Spoiled for Choice?

Management of aortic valve disease and, in particular, aortic valve stenosis has evolved through the course of time from medical management and balloon valvuloplasty to the presumed gold-standard surgical intervention. However, with the advent of surgical innovation, intra- and postoperative patients monitoring, understanding of hemodynamic dysfunction, and choices of prosthesis, conventional surgical aortic valve replacements are currently being challenged in particular in moderate- and high-risk patients. Although the long-term results and survival are not robustly available, the durability of the new prosthesis, repair, and the freedom from reoperation remain debatable. In this review, we aim to highlight the surgical innovation attained, choices of aortic valve prosthesis, and also dwell on the current evidence, practice, and trend steered to managing patients with aortic valve stenosis.

Missed aortic valve endocarditis resulting in complete atrioventricular block and redo mechanical valve replacement.

Infective endocarditis is a rare disease associated with high morbidity and mortality. As a result, early diagnosis and prompt antibiotic treatment with or without surgical intervention is crucial in the management of such condition.We report a case of missed infective endocarditis of the aortic valve. The patient underwent mechanical aortic valve replacement, with the native valve being sent for histopathological examination. On re-admission 16 months later, he presented with syncope, shortness of breathing and complete heart block. On review of the histopathology of native aortic valve, endocarditis was identified which had not been acted on. The patient underwent redo aortic valve replacement for severe aortic regurgitation.We highlight the importance of following up histopathological results as well as the need for multidisciplinary treatment of endocarditis with a combination of surgical and antibiotic therapy.

Is endoscopic long saphenous vein harvesting equivalent to open harvesting technique in terms of graft patency?

A best evidence topic was written according to a structured protocol. The question addressed was whether endoscopic vein harvesting (EVH) is equivalent to open vein harvesting in terms of graft patency for patients undergoing coronary artery bypass surgery. A total of 417 articles were found using the reported search, of which 4 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 articles are tabulated. Reported outcomes were vein graft failure or patency on coronary angiography or computed tomography angiography at early, mid and long-term follow-up. Of the non-randomized studies reviewed, those with greater patient numbers and longer follow-up periods showed reduced patency rates in the EVH group. Two small early randomized controlled trials demonstrated equivalent patency rates at up to 6 months follow-up. However, a more recent randomized controlled trial showed reduced patency with EVH in 63 patients at a median follow-up of 6.3 years. We conclude that high-quality evidence for the effects of harvesting method on vein graft patency is lacking, with no large randomized trials performed to date. The current evidence suggests that although rates of vein graft failure seem to be similar within the first 6 months following surgery, EVH is associated with reduced graft patency from 12 months onwards.

Relationship between connexin expression and gap-junction resistivity in human atrial myocardium.

BACKGROUND: The relative roles of the gap-junctional proteins connexin40 (Cx40) and connexin43 (Cx43) in determining human atrial myocardial resistivity is unknown. In addressing the hypothesis that changing relative expression of Cx40 and Cx43 underlies an increase in human atrial myocardial resistivity with age, this relationship was investigated by direct ex vivo measurement of gap-junctional resistivity and quantitative connexin immunoblotting and immunohistochemistry. METHODS AND RESULTS: Oil-gap impedance measurements were performed to determine resistivity of the intracellular pathway (Ri), which correlated with total Cx40 quantification by Western blotting (rs=0.64, P<0.01, n=20). Specific gap-junctional resistivity (Rj) correlated not only with Western immunoquantification of Cx40 (rs=0.63, P=0.01, n=20), but also more specifically, with the Cx40 fraction localized to the intercalated disks on immunohistochemical quantification (rs=0.66, P=0.02, n=12). Although Cx43 expression showed no correlation with resistivity values, the proportional expression of the 2 connexins, (Cx40/[Cx40+Cx43]) correlated with Ri and Rj (rs=0.58, P<0.01 for Ri and rs=0.51, P=0.02 for Rj). Advancing age was associated with a rise in Ri (rs=0.77, P<0.0001), Rj (rs=0.65, P<0.001, n=23), Cx40 quantity (rs=0.54, P=0.01, n=20), and Cx40 gap-junction protein per unit area of en face disk (rs=0.61, P=0.02, n=12). CONCLUSIONS: Cx40 is associated with human right atrial gap-junctional resistivity such that increased total, gap-junctional, and proportional Cx40 expression increases gap-junctional resistivity. Accordingly, advancing age is associated with an increase in Cx40 expression and a corresponding increase in gap-junctional resistivity. These findings are the first to demonstrate this relationship and a mechanistic explanation for changing atrial conduction and age-related arrhythmic tendency.

Clinical outcomes after myocardial revascularization according to operator training status: cohort study of 22,697 patients undergoing percutaneous coronary intervention or coronary artery bypass graft surgery.

AIMS: Myocardial revascularization by either coronary artery bypass graft surgery (CABG) or percutaneous coronary intervention (PCI) carries the risk of serious complications. Observational data suggest that outcomes may be improved by experienced operators, but there are few studies that have analysed the relationship between mortality and primary operator grade. The aim of this study was to investigate the effect of operator grade (trainee vs. consultant) upon outcomes of revascularization procedures. METHODS AND RESULTS: This was an observational study at a tertiary cardiology centre with accredited training programmes, between 2003 and 2011. A total of 22 697 consecutive patients undergoing either CABG or PCI were included. Associations between operator grade and mortality were assessed by hazard ratios, estimated by Cox regression analyses; 6689 patients underwent CABG, whereas 16 008 underwent PCI. Trainees performed 1968 (29.4%) CABG procedures and 8502 (53.1%) PCI procedures. The proportion of procedures performed by trainees declined over time for both CABG (30.2% in 2003 vs. 26.0% in 2010) and for PCI (58.1% in 2003 vs. 44.5% in 2010). In the unadjusted Cox analysis, consultant operator grade was associated with an increased 5-year mortality after both CABG [HR: 1.26 (95% CI: 1.07-1.47)] and PCI procedures [HR: 1.34 (95% CI: 1.22-1.47)] compared with a trainee operator. However, following multiple adjustment, consultant grade was no longer associated with mortality after either procedure [CABG: HR: 1.02 (95% CI: 0.87-1.20), PCI: HR: 1.08 (95% CI: 0.98-1.20)]. CONCLUSION: There was no observed detrimental effect on patient outcomes arising from procedures undertaken by trainees working in a structured training environment compared with consultants.

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.

A meta-analysis of cognitive outcome following coronary artery bypass graft surgery.

Coronary artery bypass graft (CABG) surgery is an established treatment for complex coronary artery disease. There is a widely held belief that cognitive decline presents post-operatively. A consensus statement of core neuropsychological tests was published in 1995 with the intention of guiding investigation into this issue. We conducted a meta-analysis evaluating the evidence for cognitive decline post-CABG surgery. Twenty-eight published studies, accumulating data from up to 2043 patients undergoing CABG surgery, were included. Results were examined at 'very early' (<2 weeks), 'early' (3 months) and 'late' (6-12 months) time periods post-operatively. Two of the four tests suggested an initial very early decrease in psychomotor speed that was not present at subsequent testing. Rather, the omnibus data indicated subtle improvement in function relative to pre-operative baseline testing. Our findings suggest improvement in cognitive function in the first year following CABG surgery. This is contrary to the more negative interpretation of results of some individual publications included in our review, which may reflect poor outcomes in a few patients and/or methodological issues.

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.