Assessment of the elderly patient for cardiac surgery

Christopher Blauth
Consultant Cardiac Surgeon, Head of Service Adult Cardiac Surgery,
Guy’s and St Thomas’ Hospital, London, UK
Correspondence: Dr Christopher Blauth, Consultant Cardiac Surgeon,
Head of Service Adult Cardiac Surgery, Guy’s and St Thomas’ Hospital, London, UK
Tel: +44 20 7960 5775, fax: +44 20 7922 8005, e-mail: christopher.blauth@gstt.sthames.nhs.uk

Introduction
We expect the seventh age of man to be a period of decline, but none of the afflictions of old age should go unchallenged. As the techniques and safety of cardiac surgery continue to improve, there has been a parallel increase in the mean age of our patients. With this has come an increased appreciation of the benefits that can be achieved by successfully relieving the cardiovascular symptoms of angina, breathlessness, and fatigue even in older age groups, and the possibility of prolonged survival. These benefits, however, come at the cost of greater operative risk.
Since age alone is probably the single most powerful risk factor for early mortality after cardiac surgery in all preoperative risk stratification models, and since most models are least accurate in predicting outcome at the highest levels of risk, surgeons need other means of assessing risk in the elderly. Primarily this becomes an exercise in utilizing the full breadth of basic clinical skills and it relies heavily on experience and clinical judgment, some of which will be largely intuitive.
The risks need to be balanced against a realistic appraisal of the potential benefits for the individual patient. In the elderly, a careful and unhurried consultation is required and the presence of a partner or family member is essential. My own practice is to consider four general questions, ordered according to the strength of the evidence base available to guide the surgeon in answering them.

How strongly is surgery indicated?
This is the first question to address. In this context, syncopal or very symptomatic severe aortic stenosis and severely symptomatic coronary disease with left main stem stenosis constitute compelling indications, whereas mitral regurgitation or diffuse coronary disease may offer more scope for successful medical management. The joint American Heart Association and American College of Cardiology guidelines for coronary artery bypass grafting[1] and valve surgery[2] are valuable for their ranking of indications, and in high-risk groups it is sensible to restrict surgical intervention for class I indications.
Cardiac surgery may be indicated to relieve symptoms or to improve survival, or both, and an evidence base exists for both indications. Unfortunately this evidence base is deficient for patients over the age of 70, which is uncomfortably close to the mean age of the patient population undergoing surgery in the UK.[3] This means that prognostic indications for surgery in the elderly are based on extrapolation of data from a younger population and must be treated with caution. Data are not available because rigorous studies have not been performed, but there is no reason to believe that improved survival cannot be achieved in carefully selected patients. However, clinical prudence favors emphasis on symptomatic indications for surgery in the elderly, and the limitations of achieving prolonged survival must be discussed candidly.
Left ventricular function must be considered at an early stage in the decision to operate. Poor left ventricular function, if irreversible in the short term, can negate any symptomatic benefit of surgery and is also a powerful risk factor for perioperative mortality. This is of less concern in severe aortic stenosis; but in ischemic heart disease, accurate differentiation between stunned or hibernating myocardium and infarction is essential and is best accomplished by stress echocardiography.

Are there any patient-related factors which might impede the successful technical accomplishment of the proposed operation or significantly increase its complexity?
Such factors may be pathological, iatrogenic or related to unusual anatomy. Pathological aspects which require careful consideration include calcification and pericarditis. Calcification of the ascending aorta renders cannulation for cardiopulmonary bypass and aortic occlusion by clamping particularly hazardous. Other arteries are available for cannulation, most commonly the femoral artery; but this too is not free of risk and may be impossible in severe arteriopathy, as well as risking retrograde dissection, which is almost invariably fatal. An alternative is infraclavicular cannulation of the subclavian artery as it becomes the axillary artery.[4] The more important limitation imposed by a severely calcific or atheromatous aorta is the inability to achieve occlusion by simple clamping. Pedicled internal mammary arterial grafts and proximal anastomosis of free grafts to them can avoid the need for manipulation of the ascending aorta for coronary bypass grafting, and off-pump surgery offers another strategy which can be employed in this situation. Access to the aortic valve is more problematic with a diseased aorta and may necessitate profound hypothermia and a period of total circulatory arrest, neither of which is desirable in the elderly. The fragility of calcified tissues can make aortic closure difficult and insecure, as well as predisposing to systemic atheroembolism, which is a major cause of stroke, and enteric ischemia.[5]
Important iatrogenic factors to consider include previous cardiac surgery, deficiency of conduits for coronary bypass following surgery for varicose veins, or mediastinal irradiation.
Obesity in the elderly can also cause major intraoperative difficulties. In obese patients, extensive fatty infiltration of mediastinal tissues and cardiac structures can impede access and increase tissue fragility. Such tissues tear and bruise easily and can be troublesome to suture, resulting in problems with postoperative hemostasis which can be severe and even fatal.

Does the patient present with comorbidity known to increase operative risk?
Neurological, pulmonary, vascular, and renal pathology are known determinants of operative risk. A history of previous stroke and increased age are the most important predictors of perioperative stroke which also carries a high mortality. A history of transient ischemic attack and known cerebrovascular disease are also significant risk factors. The presence of asthma requiring medication, known chronic obstructive pulmonary disease, or current smoking increases the probability of bronchopneumonia and ventilator dependency. Renal impairment invariably worsens temporarily after cardiac surgery, and artificial renal support may be required. All these factors are liable to prolong intensive care stay, increase the likelihood of sepsis, and produce a catabolic state which is particularly poorly tolerated in the elderly. In the very elderly, any of these factors is a strong contraindication to cardiac surgery.

What is the patient’s biological age?
Clinicians of all specialties are aware of potential discrepancies between chronological age and biological age. This discrepancy becomes more marked with advancing chronological age, and can be very striking. Energetic 80 year olds who play sports regularly and continue to care for dependants are now as common in my practice as sedentary 60 year olds who require carers. This relates largely to mobility and motivation, and the clinician needs to unravel from the patient’s history and the contributions of family members or carers how much of the patient’s current incapacity is due directly to the cardiac condition, and therefore potentially reversible, and how much relates to longstanding lifestyle choices and attitudes which are beyond the remit of the cardiac surgeon.
Despite all the technical and pharmacological improvements of recent years, cardiac surgery remains a major physical and psychological stress for the patient. Successful recovery can take up to 3 months and requires a considerable degree of effort in self-motivation and mobilization. At the same time, it is a frequent clinical observation that elderly patients often seem to embrace postoperative rehabilitation with an exemplary enthusiasm and vigor. Identifying such patients preoperatively is important.

Conclusion
Elderly patients must not be denied the opportunity of seeking relief from symptoms or life-threatening cardiac pathology through cardiac surgery. Thorough investigation and referral for assessment by an experienced surgeon are recommended. A clear and decisive surgical opinion should be expected, and the patient should leave the consultation confident that the right decision has been made.

References 

1: J Am Coll Cardiol 1999 Oct;34(4):1262-347

Related Articles, Books, LinkOut

ACC/AHA Guidelines for Coronary Artery Bypass Graft Surgery: A Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee to Revise the 1991 Guidelines for Coronary Artery Bypass Graft Surgery). American College of Cardiology/American Heart Association.

Eagle KA, Guyton RA, Davidoff R, Ewy GA, Fonger J, Gardner TJ, Gott JP, Herrmann HC, Marlow RA, Nugent WC, O'Connor GT, Orszulak TA, Rieselbach RE, Winters WL, Yusuf S, Gibbons RJ, Alpert JS, Eagle KA, Garson A Jr, Gregoratos G, Russell RO, Smith SC Jr.

Publication Types:

• Guideline
• Practice Guideline
• Review
• Review Literature

PMID: 10520819 [PubMed - indexed for MEDLINE]

2: J Heart Valve Dis 1998 Nov;7(6):672-707

Related Articles, Books, LinkOut

3. Keogh BE, Kinsman R. National Cardiac Surgical Database Report 1999–2000. The Society of Cardiothoracic Surgeons of Great Britain and Ireland.
 

4: J Thorac Cardiovasc Surg 1999 Dec;118(6):1153

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 Cardiovasc Surg. 1999;118:1153.
 

5: Ann Thorac Surg 1995 May;59(5):1300-3

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Macroemboli and microemboli during cardiopulmonary bypass.

Blauth CI.

Cardiothoracic Unit, Guy's Hospital, London, England.

Macroscopic and microscopic emboli of gas, biologic aggregates, and inorganic debris can occur during cardiac operations with cardiopulmonary bypass and may result in end-organ ischemia. In the current era pump-generated embolism is a diminishing cause of perioperative neurologic injury, which now appears to be related mostly to atheroembolism from manipulation of the atherosclerotic ascending aorta, and presents a continuing technical challenge to the surgeon.

Publication Types:

• Review
• Review, Academic

PMID: 7733756 [PubMed - indexed for MEDLINE]