Preoperative Cardiac Evaluation

Chapter 56


Preoperative Cardiac Evaluation





1. What is the natural history of perioperative cardiac morbidity?


    Perioperative cardiac morbidity occurs most commonly during the first 3 postoperative days and includes perioperative myocardial infarction (MI), unstable angina, cardiac death, and nonfatal cardiac arrests. Previously, the peak incidence of perioperative MI was thought to occur during postoperative day 3, although recent studies have suggested it occurs earlier and may arise most commonly in the first 48 hours. Additionally, the mortality from a perioperative cardiac MI has decreased from previous rates of 30% to 50% to approximately 12%. A large number of patients also demonstrate isolated biomarker elevations, which are predictive of worse long-term, but not short-term, survival.


2. What is the cause of perioperative cardiac morbidity?


    The cause of perioperative MI is multifactorial. The postoperative period is associated with a stress response, which includes the release of catecholamines and cortisol, resulting in tachycardia and hypertension. The tachycardia can lead to supply/demand mismatches distal to a critical coronary stenosis, causing myocardial ischemia, and, if prolonged, can lead to perioperative MI. Tissue injury, tachycardia, and the hypercoagulable state also leads to plaque rupture and acute thrombosis, potentially resulting in a perioperative MI. Therefore, many perioperative events will not be predicted by identifying critical stenoses or by preoperative imaging. Additionally, perioperative strategies to reduce cardiac morbidity require a multimodal approach of both reducing supply/demand mismatches and reducing the risk of acute thrombosis.


3. What are the strongest predictors of perioperative cardiac events?


    For some specific patients, surgery represents a very high risk of cardiac complications and either therapy should be initiated preoperatively or the benefits of surgery must significantly outweigh the risks if the decision is to proceed to surgery. According to the 2009 American College of Cardiology Foundation/American Heart Association (ACCF/AHA) Guidelines on Perioperative Cardiovascular Evaluation, active cardiac conditions for which the patient should undergo evaluation and treatment before noncardiac surgery include unstable coronary syndromes, active heart failure, severe valvular disease, and severe arrhythmias. Specific conditions within these general categories are shown in Table 56-1. Analysis of administrative data suggests that the elevated risk of a recent MI continues for at least the first 60 days.



TABLE 56-1


ACTIVE CARDIAC CONDITIONS FOR WHICH THE PATIENT SHOULD UNDERGO EVALUATION AND TREATMENT BEFORE NONCARDIAC SURGERY (CLASS I, LEVEL OF EVIDENCE B)










































CONDITION EXAMPLES
Unstable coronary syndromes Unstable or severe angina∗ (CCS class III or IV)†
  Recent MI‡
  Decompensated HF (NYHA functional class IV; worsening or new-onset HF)
Significant arrhythmias High-grade atrioventricular block
  Mobitz II atrioventricular block
  Third-degree atrioventricular heart block
  Symptomatic ventricular arrhythmias
  Supraventricular arrhythmias (including atrial fibrillation) with uncontrolled ventricular rate (HR > 100 beats/min at rest)
  Symptomatic bradycardia
  Newly recognized ventricular tachycardia
Severe valvular disease Severe aortic stenosis (mean pressure gradient >40 mm Hg, aortic valve area <1.0 cm2, or symptomatic)
  Symptomatic mitral stenosis (progressive dyspnea on exertion, exertional presyncope, or HF)

CCS, Canadian Cardiovascular Society; HF, heart failure; HR, heart rate; MI, myocardial infarction; NYHA, New York Heart Association.


∗According to Campeau L: Grading of angina pectoris [letter]. Circulation 54:522-523


†May include stable angina in patients who are unusually sedentary.


‡The American College of Cardiology National Database Library defines recent MI as more than 7 days but less than or equal to 1 month (within 30 days).


Modified from Fleisher LA, Beckman JA, Brown KA, et al: ACC/AHA guidelines on perioperative cardiovascular evaluation and care for noncardiac surgery: executive summary, J Am Coll Cardiol 50:1716, 2007.


4. What is the revised cardiac risk index (RCRI) and how is it used clinically?


    Cardiac risk indices for perioperative risk stratification have been used in clinical practice for more than 30 years. These indices do not inform clinicians on how to modify perioperative care specifically, but they do provide a baseline assessment of risk and the value of different intervention strategies. Calculation of an index is not a substitute for providing detailed information of the underlying heart disease, its stability, and ventricular function. The RCRI was developed by studying more than 5000 patients and identifying six risk factors, including the following:


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Jun 5, 2016 | Posted by in CARDIOLOGY | Comments Off on Preoperative Cardiac Evaluation

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