SummaryFunctional capacity is an integral component of the pre-operative evaluation of the cardiac patient for non-cardiac surgery. Stair climbing capacity has peri-operative prognostic importance. It may predict survival after lung resection and complications after major non-cardiac surgery. However, stair climbing cannot determine the aerobic metabolic capacity necessary to survive the peri-operative stress response. The potential benefits and current limitations of cardiopulmonary exercise testing to determine peri-operative aerobic capacity are discussed. Principles for the selection of an appropriate screening test of aerobic function are put forward.
SummaryIt is generally believed that plaque rupture and myocardial oxygen supply-demand imbalance contribute approximately equally to the burden of peri-operative myocardial infarction. This review critically analyses data of post-mortem, pre-operative coronary angiography, troponin surveillance, other pre-operative non-invasive investigations, and peri-operative haemodynamic predictors of myocardial ischaemia and ⁄ or myocardial infarction. The current evidence suggests that myocardial oxygen supply-demand imbalance predominates in the early postoperative period. It is likely that flow stagnation and thrombus formation is an important pathway in the development of a peri-operative myocardial infarction, in addition to the more commonly recognised role of peri-operative tachycardia. Research and therapeutic interventions should be focused on the prediction and therapy of flow stagnation and thrombus formation. Plaque rupture appears to be a more random event, distributed over the entire peri-operative admission. Patients with or at risk of cardiac disease have a 3.9% (95% CI 3.3-4.6%) risk of suffering a major peri-operative cardiac event [1]. A peri-operative myocardial infarction has an associated in-hospital mortality of 15-25% [1] and an increased risk of subsequent cardiovascular death or myocardial infarction [2].Despite this important prognostic information, there are a number of controversial and poorly understood issues surrounding peri-operative myocardial infarction. There is well established evidence that an increasing heart rate is associated with peri-operative myocardial ischaemia and myocardial infarction [3]. However, substantial evidence suggests that hypotension, hypoperfusion and coagulation are important precipitants of early peri-operative myocardial ischaemia and infarction. Understanding peri-operative myocardial infarction pathophysiology is important in addressing appropriate peri-operative therapies, which in turn have important public health implications. Presentation of peri-operative myocardial infarctionTime of presentation Since the introduction of troponin surveillance, most perioperative myocardial infarctions are identified within the first postoperative day [4], compared with identification between 48 and 72 h when creatine phosphokinase was used. The day of presentation [5][6][7] of a peri-operative myocardial infarction is shown in Fig. 1.Although the majority of peri-operative myocardial infarctions present within the first 4 days of surgery, and nearly 90% by 7 days, the range of presentation is throughout the entire hospital admission [7]. After the seventh postoperative day approximately 1% of perioperative myocardial infarctions present per day [5][6][7].Pattern of presentation of troponin elevation A study of aortic surgical patients identified three patterns of troponin elevation [8]. The first pattern was characterised
SummaryPatients with coronary artery disease presenting for major noncardiac surgery may have indications for both peri-operative b-blockade and haemodynamic optimisation. The combination of peri-operative cardiorespiratory failure and myocardial ischaemia has a grave prognosis. Recent investigations have shown that in patients with coronary artery disease, b-blockade does not depress cardiac output as much as originally thought. There may, therefore, be a place for both peri-operative b-blockade and haemodynamic optimisation. The indications for peri-operative b-blockade and haemodynamic optimisation, the effect of acute b-blockade on cardiac output in patients with coronary artery disease, and the interaction of peri-operative b-blockade and haemodynamic optimisation are discussed.Keywords Sympathetic nervous system; beta-adrenergic blockade. anaesthesia. myocardial ischaemia. Since the article by Juste et al. in 1996 [1], a number of studies have added to our understanding of peri-operative b-blockade and haemodynamic optimisation. These include the indications for peri-operative b-blockade and haemodynamic optimisation, the tolerance of acute b-blockade in patients with both coronary artery disease (CAD) and poor exercise capacity, and issues regarding both acute and chronic b-blockade during haemodynamic optimisation.Indications for peri-operative b-blockade
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