Cardiac assessment prior to non-cardiac surgery in a dedicated combined cardiac and anaesthetic clinic - vital or expensive luxury?

Abstract

Improved survival for ischaemic heart disease has resulted in greater numbers of patients with substantial cardiovascular co-morbidity presenting for non-cardiac surgery. Risk stratification of such patients is complex, and is beyond the standard surgical pre-admission clinic, resulting in patients being referred inappropriately to cardiology clinics to assess 'fitness for anaesthesia'. We therefore set up a consultant-run combined cardiology / anaesthetic (PCA) clinic in 2004. We used published objective guidelines from the American College of Physicians to assess complex patients as low < 3%), medium (3-15%) or high risk (> 15%) for major adverse cardiac events (MACE) peri-operatively. The clinic has evolved to actively manage modifiable risk pre-operatively, and to recommend a peri-operative management plan. Methods Retrospective case note review of consecutive patients referred to the PCA clinic between 1st January and 31st December 2006 was performed to determine whether objective pre-operative cardiac assessment with recommendations for peri-operative care (i) actually informs surgical decision-making and (ii) prevents peri-operative MACE. Results Seventy patients attended the PCA service in 2006. Mean age was 69 years (range 33-88); 38% were male. Fortyfive per cent were referred pending general surgical procedures, 21% orthopaedics and 15% urology. There was a median of two (range 1-5) cardiovascular risk factors for non-cardiac surgery (excluding obesity) per patient, with hypertension and documented ischaemic heart disease in a majority. An objective opinion as to the risk of MACE perioperatively could be formulated in 35 (50%) patients at the time of first appointment. In the remainder, further investigations were required with a median of one (range 1-5) tests per patient - including 24-h Holter monitor in 12 cases; echocardiography in eight; treadmill exercise test in five; myocardial perfusion imaging in five and coronary angiography in four. Cardiovascular medication changes were recommended in 30 patients (43%), indicated to modify surgical risk and / or improve symptom control / prognosis. Risk stratification was 'low risk' in 43 patients (61%), 'medium' in 14 (20%) and 'high' in 13 (19%). Forty-six patients (66%) eventually underwent the planned procedure (two of whom had required cardiac pacemaker implantation). The risk of surgery was deemed greater than the expected benefit in 15 patients (23%), two of whom subsequently underwent a lesser procedure. Of the remainder, seven experienced worsening of existing medical conditions before surgery and one needed coronary artery bypass surgery. Only 23% (3 / 13) high risk patients went ahead with surgery in contrast to 43% of the medium risk group, and 86% of the low risk cases. In the operated cohort, there was no mortality and no unplanned peri-operative admissions to ICU; there was no cardiovascular morbidity apart from one perioperative acute myocardial infarction in a high risk patient. Discussion In our experience, objective assessment of peri-operative cardiac risk in patients undergoing non-cardiac surgery with concurrent anaesthetic and cardiac input is effective in informing surgical decision-making. This audit is too small to be confident of the impact on peri-operative cardiac events, but the initial impression is favourable. Of concern, adjustment of medication was required in nearly half these patients and substantial co-morbidity unearthed in a significant minority. The joint approach of the cardiologist and the anaesthetist is invaluable in formulating pre- and peri-operative management strategies for these vulnerable patients.