12 Oct 11
Posted in Antiplatelet therapy, Pre-operatie evaluation at 19:46 by Laci
By R Hall, D Mazer
Anest Anal 2011;112:292-318
In the normal course of the delivery of care, anesthesiologists encounter many patients who are receiving drugs that affect platelet function as a fundamental part of primary and secondary management of atherosclerotic thrombotic disease. There are several antiplatelet drugs available for use in clinical practice and several under investigation. Aspirin and clopidogrel (alone and in combination) have been the most studied and have the most favorable risk-benefit profiles of drugs currently available. Prasugrel was recently approved for patients with acute coronary syndrome undergoing percutaneous interventions. Other drugs such as dipyridamole and cilostazol have not been as extensively investigated. There are several newer investigational drugs such as cangrelor and ticagrelor, but whether they confer significant additional benefits remains to be established. Management of patients who are receiving antiplatelet drugs during the perioperative period requires an understanding of the underlying pathology and rationale for their administration, pharmacology and pharmacokinetics, and drug interactions. Furthermore, the risk and benefit assessment of discontinuing or continuing these drugs should be made bearing in mind the proposed surgery and its inherent risk for bleeding complications as well as decisions relating to appropriate use of general or some form of regional anesthesia. In general, the safest approach to prevent thrombosis seems to be continuation of these drugs throughout the perioperative period except where concerns about perioperative bleeding outweigh those associated with the development of thrombotic occlusion. Knowledge of the pharmacodynamics and pharmacokinetics of antiplatelet drugs may allow practitioners to anticipate difficulties associated with drug withdrawal and administration in the perioperative period including the potential for drug interactions.
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11 Apr 11
Posted in Coronary artery disease, Pre-operatie evaluation at 11:48 by Laci
By D Wijeysundera, W Beattie, R Elliot, P Austin, J Hux, A Laupacis
BMJ 2010; 340:b5526
To determine the association of non-invasive cardiac stress testing before elective intermediate to high risk non-cardiac surgery with survival and hospital stay.
Design
Population based retrospective cohort study.
Setting
Acute care hospitals in Ontario, Canada, between 1 April 1994 and 31 March 2004.
Participants
Patients aged 40 years or older who underwent specific elective intermediate to high risk non-cardiac surgical procedures.
Interventions Non-invasive cardiac stress testing performed within six months before surgery.
Main outcome measures
Postoperative one year survival and length of stay in hospital.
Results
Of the 271 082 patients in the entire cohort, 23 991 (8.9%) underwent stress testing. After propensity score methods were used to reduce important differences between patients who did or did not undergo preoperative stress testing and assemble a matched cohort (n=46 120), testing was associated with improved one year survival (hazard ratio (HR) 0.92, 95% CI 0.86 to 0.99; P=0.03) and reduced mean hospital stay (difference −0.24 days, 95% CI −0.07 to −0.43; P<0.001). In an analysis of subgroups defined by Revised Cardiac Risk Index (RCRI) class, testing was associated with harm in low risk patients (RCRI 0 points: HR 1.35, 95% CI 1.05 to 1.74), but with benefit in patients who were at intermediate risk (RCRI 1-2 points: 0.92, 95% CI 0.85 to 0.99) or high risk (RCRI 3-6 points: 0.80, 95% CI 0.67 to 0.97).
Conclusions
Preoperative non-invasive cardiac stress testing is associated with improved one year survival and length of hospital stay in patients undergoing elective intermediate to high risk non-cardiac surgery. These benefits principally apply to patients with risk factors for perioperative cardiac complications.
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04 Apr 11
Posted in Anesthesia, Pre-operatie evaluation at 1:01 by Laci
By A Klein, J Arrowsmith
Anaesthesia 2010;65:974–976
In January 2010, the Association of Anaesthetists of Great Britain and Ireland published its safety guideline Pre-operative Assessment and Patient Preparation – The Role of the Anaesthetist 2. The opening line of the section on tests and investigations states that ‘Routine pre-operative investigations are expensive, labour intensive and of questionable value, especially as they may contribute to morbidity or cause additional delays due to spurious results’. Citing Clinical Guidelines 3, published in 2004 by the National Institute for Clinical Excellence (NICE), the authors go on to recommend that routine tests should indeed be undertaken in a number of specific patient groups before most types of surgery, including many procedures that are typically performed on a day-case basis. In the prevailing economic climate, can continued expenditure on tests of questionable value be justified, and is there sufficient evidence to consider abandoning routine pre-operative testing altogether?
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01 Apr 11
Posted in Pre-operatie evaluation at 21:28 by Laci
By D Poldermans, J Bax, E Boersma, S De Hert, E Eeckhout at al
Eur Heart J (2009) 30(22): 2769-2812
The present guidelines focus on the cardiological management of patients undergoing non-cardiac surgery, i.e. patients where heart disease is a potential source of complications during surgery. The risk of perioperative complications depends on the condition of the patient prior to surgery, the prevalence of co-morbidities, and the magnitude and duration of the surgical procedure.3 More specifically, cardiac complications can arise in patients with documented or asymptomatic ischaemic heart disease (IHD), left ventricular (LV) dysfunction, and valvular heart disease (VHD) who undergo procedures that are associated with prolonged haemodynamic and cardiac stress. In the case of perioperative myocardial ischaemia, two mechanisms are important: (i) chronic mismatch in the supply-to-demand ratio of blood flow response to metabolic demand, which clinically resembles stable IHD due to a flow limiting stenosis in coronary conduit arteries; and (ii) coronary plaque rupture due to vascular inflammatory processes presenting as acute coronary syndromes (ACSs). Hence, although LV dysfunction may occur for various reasons in younger age groups, perioperative cardiac mortality and morbidity are predominantly an issue in the adult population undergoing major non-cardiac surgery.
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