Chapter 4 Investigation, workup and patient preparation before PCI
INTRODUCTION
A anticipation (of possible complications).
There is inevitably some overlap between these elements, all of which require consideration in all patients. The emergency nature of some procedures (e.g. primary PCI for a patient with an acute ST-elevation myocardial infarction) may curtail the time available for preparation of the patient, but should never result in omission of the basic essentials.
PRELIMINARY INVESTIGATIONS
These are needed to allow three questions to be answered:
With few exceptions, PCI should only be considered in a patient with symptoms of coronary artery disease, objective evidence of myocardial ischaemia/infarction and an anatomically suitable lesion(s), as demonstrated by coronary angiography. As a preliminary to such a procedure, therefore, the interventional cardiologist should review the patient’s history and the results of any non-invasive and invasive investigations. While all this information should be available in advance of procedures performed electively, it is now increasingly common that patients, especially those with acute coronary syndromes (ACS: unstable angina or acute myocardial infarction), have combined diagnostic (i.e. coronary angiography) and therapeutic (i.e. PCI) procedures performed. In this situation, it is especially important for the interventional cardiologist to retain a capacity for objective judgement, so that, for instance, a patient who might best be treated surgically does not receive sub-optimal treatment simply because it is ‘convenient’ and it has been scheduled.
Before arrival in the cardiac catheterisation laboratory, every patient should have a clinical history documented and a physical examination performed (Fig. 4.1). These should be supplemented by some basic investigations, although the number of these will be kept to a minimum in emergency situations (Table 4.1).
ALL PATIENTS |
It is of particular importance to discover conditions that might increase the technical difficulty or risk of an invasive cardiac procedure. Some such factors can be corrected but awareness of others may lead to changes in peri-procedural drug therapy (see Therapeutics below), the information provided to the patient (see Consent below) or an ability to predict, and hopefully prevent, possible complications (see Anticipation below).
THERAPEUTICS (TABLE 4.2)
Anti-anginal drugs
DRUG CLASS | ACTION REQUIRED |
---|---|
Oral anti-anginal drugs | Continue |
Cholesterol-lowering therapy | Continue |
Oral anti-platelet therapy | Ensure that aspirin has been taken |
ADMINISTER LOADING DOSE OF CLOPIDOGREL (IF NOT ALREADY PRESCRIBED) | |
Warfarin | Discontinue if possible |
Measure INR and correct excessive anticoagulation | |
TAKE APPROPRIATE MEASURES TO AVOID HAEMORRHAGE AT VASCULAR ACCESS SITE | |
IV Heparin | Continue |
Measure ACT and consider reduced bolus dose | |
SC Low molecular-weight heparin | Administer last injection >12 hours prior to PCI (if possible) |
GP IIb/IIIa receptor antagonists | Continue but consider the use of a reduced, weight-adjusted heparin regime |
Pre-medication | If necessary, use diazepam 5–20 mg orally |
Antidiabetic medication | See text |
Other drug therapy | Continue unchanged |