Complete Versus Culprit-Only Revascularization in Acute Coronary Syndrome

Definition and pathophysiology

In acute coronary syndrome (ACS) with multivessel coronary artery disease (MVD), revascularization may be directed exclusively at the infarct-related artery (IRA), or it may extend to additional non-infarct-related lesions. Culprit-only revascularization treats the artery responsible for the acute clinical event during the index procedure. Complete revascularization aims to treat all lesions producing myocardial ischaemia, either during the same procedure or through staged intervention.

The rationale for complete revascularization is that untreated, flow-limiting disease may continue to cause ischaemia, recurrent symptoms, myocardial infarction, or other major adverse cardiovascular events. Complete revascularization is therefore considered an important therapeutic objective, particularly in patients with left ventricular dysfunction and/or MVD. Nevertheless, the optimal extent and timing of intervention depend on the clinical setting, haemodynamic status, coronary anatomy, comorbidities, procedural complexity, age, frailty, and anticipated adherence to antithrombotic therapy.

Anatomical and functional completeness are not synonymous. Anatomically incomplete revascularization may nevertheless be functionally complete if all lesions causing ischaemia have been treated. Conversely, angiographically satisfactory stenting may leave clinically relevant residual ischaemia, particularly after complex coronary intervention. The clinical importance of residual disease is also influenced by anatomic complexity and comorbidity, which themselves may contribute to progression of native coronary artery disease.

The chronic total occlusion is an important predictor of incomplete anatomical revascularization with PCI. PCI of chronic total occlusion lesions may improve angina and quality of life, but randomized trials have not demonstrated reductions in mortality or myocardial infarction rates.

Clinical presentation and symptoms

The clinical presentation is determined primarily by the ACS syndrome and the haemodynamic consequences of the culprit lesion. Patients may present with ST-segment elevation myocardial infarction (STEMI), non-ST-elevation ACS (NSTE-ACS), or ACS complicated by cardiogenic shock.

In NSTE-ACS, a strategy involving coronary angiography and subsequent revascularization may be undertaken early, delayed, or selectively after initial medical treatment. The presence of ST-segment changes or a positive troponin assay identifies patients in whom an invasive strategy is generally preferred over selective angiography, provided that there is no contraindication and the coronary anatomy is suitable.

In cardiogenic shock, the principal precipitating mechanisms include ischaemia-related heart failure, acute severe mitral regurgitation, and other mechanical complications. Shock occurs more often when the coronary artery is completely occluded and is particularly associated with MVD. Patients with ACS and shock should be transferred promptly to a tertiary centre with appropriate expertise and a dedicated multidisciplinary Shock Team.

Evaluation and physical examination

Assessment should establish:

• The ACS presentation and its urgency.

• The presence or absence of haemodynamic instability or cardiogenic shock.

• The likelihood of an identifiable IRA.

• The extent and complexity of coexisting coronary disease.

• Renal function, bleeding risk, comorbidities, frailty, and anticipated adherence to antithrombotic treatment.

• Whether the patient is suitable for PCI, CABG, or an initial medical strategy.

In haemodynamically unstable patients, evaluation must also consider acute severe mitral regurgitation, mechanical complications, and ischaemia-related ventricular failure as potential causes of shock. Patients with moderate-to-severe chronic kidney disease have a higher burden of comorbidity and an increased risk of in-hospital complications, including serious bleeding.

Clinical judgement is particularly important when the expected procedural benefit is uncertain. An initial conservative strategy may be reasonable in selected, medically stabilized patients with small-calibre vessels, an occluded small side branch, concerns about compliance with antithrombotic treatment, or anticipated complex PCI requiring Heart Team discussion.

Diagnostics

Electrocardiography

The available source material distinguishes STEMI from NSTE-ACS and refers to ST-segment elevation or equivalent ECG patterns, as well as ST-segment changes in NSTE-ACS. It does not provide a detailed ECG diagnostic framework or specific electrocardiographic criteria for identifying the IRA or non-culprit lesions.

Coronary angiography

In ACS complicated by cardiogenic shock, immediate coronary angiography is recommended, with PCI when feasible. If coronary anatomy is unsuitable for PCI, emergency CABG is recommended.

In haemodynamically stable STEMI patients undergoing primary PCI, complete revascularization is recommended either during the index procedure or within 45 days. PCI of non-IRA lesions should be based on angiographic severity. Invasive epicardial functional assessment of non-culprit segments during the index procedure is not recommended in this setting.

For NSTE-ACS with MVD, complete revascularization should be considered, preferably during the index procedure. Functional invasive assessment of non-IRA lesion severity during the index procedure may be considered, although the supporting evidence is less robust.

Intravascular imaging

Intravascular imaging is useful when coronary angiography does not show significant obstructive disease, when the culprit lesion is uncertain, and when multiple potential culprit lesions are present. It can help exclude an atherothrombotic cause in the major coronary arteries and thereby influence both acute management and decisions concerning prolonged antithrombotic treatment.

Intravascular ultrasound (IVUS) is also established as a tool to guide and optimize PCI. Randomized-trial meta-analysis supports IVUS-guided intervention for reducing major adverse cardiovascular events, although a definitive large multinational trial is lacking. Optical coherence tomography has also been evaluated in smaller randomized studies.

Non-invasive imaging

The source material does not provide a specific role for echocardiography, cardiac magnetic resonance, or computed tomography in selecting complete versus culprit-only revascularization in ACS. Coronary computed tomography angiography is mentioned in other clinical contexts but no specific recommendation is provided for this decision.

Biomarkers and laboratory findings

A positive troponin assay is identified as a high-risk feature in NSTE-ACS and supports an invasive strategy over selective angiography when there is no contraindication and the anatomy is appropriate.

Renal function is central to procedural planning. In patients with moderate-to-severe chronic kidney disease, the dose and type of antithrombotic therapy and the amount of contrast medium should be adjusted according to kidney function. Intravenous hydration during and after revascularization should be considered in patients with a low estimated glomerular filtration rate undergoing invasive management, although the evidence concerning the optimal fluid choice, timing, and duration is conflicting.

The source material does not provide additional biomarker thresholds or laboratory criteria for choosing complete versus culprit-only intervention.

Treatment and management

General principles

Complete revascularization is generally preferred when it can be performed safely and when all clinically relevant ischaemic lesions can be identified and treated. However, completeness should not be pursued indiscriminately. The decision must integrate:

• Clinical presentation and haemodynamic stability.

• The urgency of reperfusion.

• Coronary anatomy and lesion complexity.

• Left ventricular function.

• Renal function and bleeding risk.

• Age, frailty, and comorbidities.

• The ability to adhere to antithrombotic treatment.

• The feasibility of PCI versus CABG.

• The availability and expertise of the treating team.

• Patient preferences and shared decision-making.

In complex disease, staged treatment may allow more careful assessment of residual ischaemia, procedural risk, and the most appropriate revascularization modality.

Cardiogenic shock

Rapid revascularization of the IRA is the principal evidence-based intervention associated with mortality reduction in ACS-related cardiogenic shock. PCI with a drug-eluting stent is generally preferred when feasible.

For patients with shock and MVD, PCI during the index procedure should be restricted to the IRA. Immediate multivessel PCI is associated with worse outcomes than an IRA-only strategy, including a higher combined risk of death or renal replacement therapy at 30 days. Non-IRA PCI may be performed as a staged procedure when clinically appropriate.

If the anatomy is unsuitable for PCI, emergency CABG is recommended. Patients should be transferred as soon as possible to a tertiary shock centre capable of coronary angiography and advanced multidisciplinary management.

Haemodynamically stable STEMI

In haemodynamically stable STEMI patients undergoing primary PCI, complete revascularization is recommended either during the index procedure or within 45 days. Non-IRA intervention should be guided by angiographic severity.

This recommendation differs fundamentally from the approach in cardiogenic shock: immediate multivessel PCI should be avoided in shock, whereas complete revascularization is recommended in stable STEMI, provided that the patient and anatomy are suitable.

NSTE-ACS with multivessel disease

Evidence is less extensive for NSTE-ACS than for STEMI. No dedicated randomized trial has directly compared complete revascularization with IRA-only PCI in NSTE-ACS with MVD. Observational studies and meta-analyses of non-randomized data suggest fewer deaths and major adverse cardiovascular events with complete revascularization, but these findings are hypothesis-generating and cannot establish a definitive treatment effect.

Current recommendations state that complete revascularization should be considered, preferably during the index procedure. Functional invasive assessment of non-IRA lesion severity during the index procedure may be considered.

An early invasive strategy is generally preferred in NSTE-ACS with ST-segment changes and/or a positive troponin assay, including when these high-risk features arise during the first 24 hours. An early invasive approach is not recommended when extensive comorbidity makes the risks of revascularization outweigh its potential benefits, or when ACS is clinically unlikely and troponin testing is negative.

Selecting PCI, CABG, or medical therapy

There are no dedicated randomized trials directly comparing PCI with CABG in ACS patients. In STEMI, CABG is generally reserved for situations in which primary PCI is not feasible, particularly with ongoing ischaemia or a large jeopardized myocardial territory. In very high-risk NSTE-ACS requiring immediate revascularization, PCI is usually preferred because of its greater timeliness, unless mechanical complications favour surgery.

For other ACS presentations, the choice between PCI and CABG follows general myocardial revascularization principles. In MVD, the decision is influenced by anatomic complexity, comorbidities including diabetes, surgical risk, and the likelihood of achieving complete revascularization.

CABG has a greater ability than PCI to achieve complete revascularization, particularly in triple-vessel disease, and provides a conduit to the distal native vessel beyond potential future stenoses. In pooled randomized data, survival among patients achieving complete revascularization was similar with CABG and PCI, whereas CABG was superior when revascularization remained incomplete.

The decision should also consider:

• Quality and experience of the available surgical and interventional teams.

• Patient preference regarding invasiveness, recovery, symptom recurrence, and possible reintervention.

• Advanced age, frailty, and comorbid conditions, which may favour PCI in selected patients.

• The possibility that staged PCI may achieve an acceptable functional result even when anatomical completeness is not immediately achieved.

Medical therapy alone may be appropriate in carefully selected patients, particularly when symptoms are controlled, the anatomy is unsuitable for intervention, procedural risk is excessive, or antithrombotic adherence is doubtful. In patients with small-calibre vessels or an occluded small side branch, conservative management with optimized guideline-directed therapy may be considered case by case.

Antithrombotic and procedural considerations

The source material does not specify antiplatelet or anticoagulant doses for complete or culprit-only revascularization. It does, however, emphasize that concerns regarding adherence to antithrombotic therapy may influence the choice of an initial conservative strategy.

Renal function should guide antithrombotic dosing and contrast use. Radial arterial access is preferred over femoral access when feasible because of its greater safety. Intravascular imaging should be considered for PCI planning and optimization, particularly when lesion morphology or stent deployment is uncertain.

Guideline recommendations

The source material also reports that, in one guideline comparison, complete revascularization in MVD was assigned a class IIa recommendation with level of evidence C in the ESC framework, while another tabulated comparison lists class IIb, level B. Because the source presents these classifications inconsistently, the recommendation should be interpreted in the context of the specific clinical setting, particularly the distinction between STEMI, NSTE-ACS, and cardiogenic shock.

Prognosis and follow-up

Prognostic implications

In ACS with cardiogenic shock, early revascularization improves longer-term survival compared with initial medical stabilization, although the early mortality difference was not significant in the cited trial. In patients with shock and MVD, IRA-only PCI reduces the combined risk of death or renal replacement therapy at 30 days compared with immediate multivessel PCI; a significant mortality difference between the strategies was not demonstrated at one year.

Incomplete revascularization has been associated with higher mortality than complete revascularization. Interpretation is difficult because incomplete treatment may reflect more complex coronary anatomy, greater comorbidity, chronic total occlusion, or the need for staged procedures. In PCI-treated patients, a higher residual SYNTAX score, reflecting greater anatomical incompleteness, is associated with higher mortality. Functional completeness may nevertheless produce better outcomes than anatomical completeness without regard to ischaemia.

After CABG, graft failure may occur during the first year without symptoms, so apparent completeness at the time of surgery does not guarantee durable complete revascularization.

Follow-up strategy

Follow-up should reassess:

• Persistence or recurrence of angina and functional limitation.

• Evidence of residual or recurrent ischaemia.

• Left ventricular function and heart-failure status where clinically relevant.

• Renal function, particularly after contrast exposure or in established chronic kidney disease.

• Bleeding and adherence to antithrombotic treatment.

• Whether staged non-IRA PCI remains indicated.

• The need for Heart Team reassessment when revascularization is incomplete or symptoms persist.

Patients with complex CAD may require staged intervention or further multidisciplinary review rather than immediate treatment of every angiographic lesion. The long-term plan should therefore be based on the patient’s clinical course, residual ischaemia, anatomical complexity, procedural risk, and preferences.