Anaesthetic problems associated with the treatment of cardiovascular disease: II. Beta-adrenergic antagonists

Beta-receptor blocker withdrawal. A preoperative problem in general surgery?

A prospective randomized study was performed in 91 patients scheduled for general surgery on 99 occasions. The patients were chronically (greater than 3 months) treated with beta-receptor blockers because of ischaemic heart disease and/or hypertension and the beta-receptor blockade was either gradually withdrawn (n = 51) during 4 days preoperatively or continued until surgery (n = 48). The effects on arterial blood pressure (BP), heart rate (HR) and rate-pressure product (RPP) at rest and the incidence of chest pain during daily activities were registered. A withdrawal of the beta-receptor blockade was associated with increases of HR (in eight patients greater than 30 beats min-1) and RPP and in patients treated for hypertension there were also increases of systolic and diastolic BP (in five patients greater than or equal to 30/15 mmHg). Patients who continued the beta-receptor blockade until surgery showed no changes. Nine out of 23 patients with a previous history of ischaemic heart disease had an increase of chest pain after withdrawal of the beta-receptor blockers, whereas none of the corresponding 25 patients who continued the therapy suffered from an increased chest pain. Due to the severity of symptoms after beta-receptor blocker withdrawal, surgery had to be postponed in 4 patients. The observations suggest that a 4-day preoperative withdrawal of long-term beta-receptor blockade is potentially hazardous in ischaemic and/or hypertensive patients.

Anaesthesia for cardiac patients having non-cardiac operations

It is difficult to pick out a sensitive marker for the effectiveness with which patients with heart disease have been managed for non-cardiac operations. Reinfarction rates have frequently been cited for this purpose over the past 20 years and it is interesting and perplexing that, until very recently, we have been unable to show significant decreases in reinfarction rates in patients who have had a myocardial infarction within six months of surgery. It has been our opinion for a number of years that, in general, patients with heart disease are well managed in the intraoperative phase of their hospital stay. The successful management of patients during this period is based on the fact that the majority of anaesthetists now appear to have a good understanding of the pathophysiology of heart disease and are becoming more aggressive in the monitoring and treatment of abnormal haemodynamics when they occur. The ultimate extent to which morbidity and mortality can be reduced in patients with heart disease for non-cardiac surgery will not be known until patients at high risk receive the same intensive postoperative care that patients who undergo heart surgery enjoy. It is the fact that patients are haemodynamically stable and do not have myocardial ischaemia throughout the peri-operative period that is important, rather than the way in which it is achieved.