What pre‑hospitalisation investigations are required for cardiac procedures—including coronary angiography (CAG), coronary artery bypass grafting (CABG), percutaneous transluminal coronary angioplasty (PTCA), triple‑vessel disease (TVD) management, ischemic heart disease (IHD) treatment, pacemaker implantation, valve surgery, and aortic replacement?

Pre-Hospitalisation Investigations for Cardiac Procedures

All patients being considered for cardiac procedures—whether conservative management, CAG, PTCA, CABG, pacemaker implantation, valve surgery, or aortic replacement—require a standardized baseline assessment including ECG, chest X-ray, transthoracic echocardiography (TTE), complete blood count, and coagulation screen before hospitalization 1.

Core Baseline Investigations (Required for All Patients)

The following investigations form the foundation of pre-hospitalization assessment 1:

• 12-lead ECG: Identifies rhythm abnormalities, conduction defects, prior infarction, and ischemic changes
• Chest X-ray: Assesses cardiac silhouette, pulmonary vasculature, and lung fields
• Transthoracic echocardiography (TTE): Evaluates ventricular function, valve pathology, chamber dimensions, and wall motion abnormalities
• Complete blood count: Detects anemia, thrombocytopenia, or polycythemia (especially in cyanotic patients)
• Coagulation screen: Baseline PT/INR, aPTT before anticoagulation or surgery
• Systemic arterial oximetry: Particularly critical in patients with suspected shunts or cyanotic disease 1

Risk-Stratified Additional Investigations

For Coronary Angiography (CAG) and Revascularization (PTCA/CABG)

Coronary angiography itself serves as both diagnostic and pre-procedural assessment 2. However, before proceeding to angiography:

• Troponin levels (on admission and at 12 hours): Elevated troponins identify high-risk patients requiring urgent angiography 2, 3
• Renal function (serum creatinine/eGFR): Critical for contrast-related nephropathy risk and identifies patients with creatinine >170 μmol/L (2 mg/dL) or clearance <60 mL/min as high-risk 3, 4
• Blood glucose/HbA1c: Diabetes requiring insulin therapy is a major clinical risk factor 3, 4

High-risk patients requiring urgent angiography during initial hospitalization include those with 2, 3:

• Recurrent ischemia (chest pain or dynamic ST-segment changes)
• Elevated troponin levels
• Hemodynamic instability (hypotension, pulmonary edema)
• Major arrhythmias (ventricular tachycardia, ventricular fibrillation)
• Early post-infarction unstable angina

For CABG Surgery Specifically

Beyond baseline investigations, CABG candidates require 5, 6:

• Coronary angiography: Mandatory to define anatomy—identifies left main disease, triple-vessel disease (TVD), and lesion complexity
• Society of Thoracic Surgeons (STS) risk score calculation: Recommended to stratify surgical mortality risk 6
• SYNTAX score (may be useful): Assesses coronary lesion complexity to guide revascularization strategy, though has interobserver variability 6
• Assessment for concomitant CAD severity: Lesions ≥70% stenosis require bypass grafting; 50-70% stenosis may reasonably undergo grafting 5

Common pitfall: Do not delay urgent CABG for extensive preoperative testing in hemodynamically unstable patients 5. Emergency surgery for acute aortic regurgitation, dissection, or endocarditis with instability should proceed without catheterization 5.

For Valve Surgery and Aortic Replacement

Coronary angiography is mandatory before valve surgery in 5:

• Men ≥40 years old
• Postmenopausal women
• Patients with coronary risk factors
• Patients with history or symptoms of CAD
• Patients with LV systolic dysfunction

Additional valve-specific investigations 7:

• 3D transesophageal echocardiography (TEE): For detailed valve anatomy assessment, particularly mitral valve
• Cardiac CT: Defines aortic root dimensions, coronary anatomy, and vascular access for transcatheter approaches
• Baseline post-procedural TTE: Ideally 1-3 months after intervention to establish new baseline 7

Do not perform coronary angiography in 5:

• Young patients (<40 years men, premenopausal women) without coronary risk factors undergoing non-emergency valve surgery
• Severely hemodynamically unstable patients where delay would be harmful

For Pacemaker Implantation

Pre-hospitalization workup focuses on defining indication 8:

• Continuous ECG monitoring/Holter: Documents bradycardia (<40 bpm), sinus pauses (>3 seconds), or AV block
• Echocardiography: Assesses ventricular function and identifies structural heart disease
• Review of surgical records and imaging (echo, CT, or MRI): Essential to define vascular anatomy and identify obstructions before transvenous lead placement 8
• Comprehensive shunt evaluation (echo or angiography): Required before transvenous leads in patients with intracardiac shunts 8

For Triple-Vessel Disease (TVD) Management

TVD patients require comprehensive risk stratification 2, 9:

• Coronary angiography: Defines extent and suitability for PCI vs. CABG
• LV function assessment (echocardiography): LV dysfunction favors CABG over PCI 2
• Renal function: eGFR is inversely associated with mortality in NSTEMI with TVD 9
• Systolic blood pressure at admission: Lower SBP predicts worse outcomes 9
• Diabetes status: Diabetic patients with multivessel disease have better outcomes with CABG than PCI 6

Decision algorithm for TVD 2:

• Left main or TVD with LV dysfunction → CABG (unless serious comorbidity contraindicates surgery)
• Single-vessel disease → PCI of culprit lesion
• Double-vessel or some TVD cases → Either PCI or CABG acceptable; consider staged procedure

For High-Risk Surgical Populations

Certain patients require management at specialized centers and need additional assessment 1:

High-risk categories include:

• Prior Fontan procedure
• Severe pulmonary arterial hypertension
• Cyanotic congenital heart disease
• Complex CHD with residua (heart failure, valve disease)
• Malignant arrhythmias

Additional investigations for high-risk patients 1:

• Cardiac catheterization: Gold standard for pulmonary vascular resistance in pulmonary hypertension
• Consultation with cardiac anesthesiologist: Mandatory for moderate- and high-risk patients 1
• Preoperative phlebotomy: If hematocrit >65% in cyanotic patients to reduce bleeding risk 1

Timing Considerations

For acute coronary syndromes requiring urgent intervention 2, 3:

• Coronary angiography should be performed "as soon as possible" in high-risk patients
• Most cases: within 48 hours of admission
• Severe ongoing ischemia, major arrhythmias, hemodynamic instability: within first hour

For elective procedures 4:

• Complete preoperative assessment optimally 30 days to 1 week before surgery
• Allows time for medical optimization (beta-blockers, statins)

Critical Pitfalls to Avoid

1. Do not perform stress testing in unstable patients—proceed directly to angiography in high-risk acute coronary syndromes 2
2. Do not delay emergency surgery for catheterization in hemodynamically unstable valve patients 5
3. Do not use fixed high-dose beta-blockers without titration perioperatively—associated with harm 4
4. Do not place transvenous pacemaker leads without shunt evaluation in patients with intracardiac shunts—risk of thromboembolism 8
5. Do not assume normal coronary anatomy—angiography is required before valve surgery in at-risk populations even without symptoms 5