Peri-operative Cardiovascular Complications
Table 2. Cardiac Risk* Stratification for Non-cardiac Surgical Procedures13
Risk Stratification Vascular (reported
cardiac risk often >5%) Intermediate (reported
cardiac risk generally 1–5%) Procedure Examples
Aortic and other major vascular surgery Peripheral vascular surgery
Intraperitoneal and intrathoracic surgery
Carotid endarterectomy Head and neck surgery Orthopaedic surgery Prostate surgery
Low† (reported cardiac risk generally
Superficial procedure Cataract surgery Breast surgery Ambulatory surgery
*Combined incidence of cardiac death and non-fatal myocardial infarction. †These procedures do not generally require further pre-operative cardiac testing.
symptomatic two-vessel CAD involving the proximal left anterior descending (LAD) artery and angina refractory to medical therapy.26 To date, there have been no randomised trials supporting the role of prophylactic coronary revascularisation to reduce cardiovascular complications in non-cardiac surgery. However, a number of observational studies have suggested improved outcomes in patients with CAD and successful prior revascularisation. A review of patients in the Coronary Artery Surgical Study (CASS) database with previous coronary artery bypass grafting (CABG) who subsequently underwent high-risk non-cardiac surgery revealed a significant reduction in 30-day mortality and non-fatal MI compared with patients receiving medical therapy alone.27
A similar review of Medicare recipients also reported significant improvements in both short- and long-term survival in patients undergoing CABG prior to high-risk aortic surgery.28
Patients previously treated Likewise,
observations of reduced cardiac events have been noted with percutaneous coronary intervention (PCI).29
Over 8,000 patients with or at risk of CAD in the PeriOperative ISchemic Evaluation (POISE) trial were randomised to fixed-dose extended-release metoprolol versus placebo on the day of surgery and were found to have a reduction in peri-operative MI at the cost of increased stroke and overall mortality casting suspicion on the beneficial effects of acute high-dose prophylactic beta-blocker use.19
other trials have been unable to confirm this cardioprotective benefit and the largest randomised trial to date has suggested potential harm.16–18
By
contrast, intermediate-risk patients in the recent DECREASE-IV trial who were given titrated doses of bisoprolol and either fluvastatin or placebo in a randomised unblinded fashion demonstrated a reduction in non-fatal MI and cardiac death at 30 days with no apparent increase in stroke.20
Based on cumulative data thus far, it is recommended that beta-blockers be continued in those patients already prescribed them for other indications and be considered as treatment for intermediate- and high-risk patients undergoing intermediate- or high-risk procedures.21
Beta-blockers are no longer recommended as
routine treatment in low-risk patients who do not otherwise have an indication for them; if initiated, therapy should begin ideally well before the planned procedure with doses carefully titrated to optimise the resting heart rate while avoiding significant hypotension. Given their effectiveness in the medical treatment of CAD, 3-hydroxy-3- methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors (statins) have also been investigated as a means of lowering peri-operative cardiovascular complications. The pleiotropic effects of statins are well documented and it is these effects (plaque stabilisation, reduced vascular inflammation, improved endothelial function) that would seem to make statins the ideal agents for vascular protection from the physiological stress of surgery.22
Along with observational data, the
strongest evidence to date for the beneficial effects of statins stems from the DECREASE-III trial in which patients undergoing vascular surgery randomised to fluvastatin experienced significantly less myocardial ischaemia and the combined secondary end-point of cardiac mortality and MI.23,24
Statins are also considered potentially helpful in those with at least one clinical risk factor undergoing intermediate-risk procedures.13
Coronary Revascularisation
Among the indications for coronary revascularisation in the general population with stable CAD is left main or severe three-vessel CAD,
106
with angioplasty in the Bypass Angioplasty Revascularisation Investigation (BARI) trial later proceeding with non-cardiac surgery had low peri-operative cardiovascular complication rates that were similar to those with CABG revascularisation.30
The largest randomised trial to date designed to evaluate the strategy of prophylactic coronary revascularisation in high-risk patients undergoing vascular surgery is the Coronary Artery Revascularisation Prophylaxis (CARP) trial.31
In the CARP trial, 510 patients scheduled
to undergo elective major vascular surgery deemed at high risk of cardiovascular complications were randomised to revascularisation or no revascularisation after obstructive CAD was identified by coronary angiography. Half of the patients enrolled had two or more RCRI risk factors and three-quarters had either multiple clinical risk factors or moderate to large reversible defects on non-invasive stress imaging. The majority of patients had normal left ventricular ejection fraction (EF) with single- or two-vessel disease while three-vessel disease was seen in one-third of the total population. Excluded were patients with EF 50% angiographic stenosis). Patients randomised to receive revascularisation underwent either CABG or PCI at the discretion of the operator and experienced no reduction in peri-operative MI or death at 30 days and saw no improvement in long-term mortality after six years.
Subsequently, the recent DECREASE-V pilot study randomised 101 patients with three or more clinical risk factors and extensive ischaemia planning major vascular surgery to either revascularisation or optimal medical treatment with antiplatelet therapy and beta-blockade titrated to a resting heart rate of less than 65 beats per minute.32
The
Statins are recommended for patients who meet National Cholesterol Education Program criteria for treatment and are felt to be beneficial in all patients undergoing vascular non-cardiac surgery.25
DECREASE-V patient population had more three-vessel CAD (67%) and a higher percentage of left ventricular systolic dysfunction (EF
Surgical Coronary Revascularisation
Despite the lack of definitive data supporting prophylactic coronary revascularisation for the reduction of peri-operative cardiovascular complications, additional evidence suggests a potential benefit in
INTERVENTIONAL CARDIOLOGY
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