Intravascular Imaging-Guided vs. Angiography-Guided Complex PCI: What Patients Need to Know

Table of Contents

• Key Points
• Background: Why This Research Matters
• How the Study Was Conducted
• Patient Characteristics
• Procedural Details
• Key Findings: What the Study Showed
• Subgroup and Additional Analyses
• Safety Outcomes
• What This Means for Patients
• Limitations of the Study
• Recommendations
• Frequently Asked Questions
• Source Information

Key Points

• In a trial of 1,639 patients with complex coronary lesions, intravascular imaging-guided PCI reduced the combined risk of cardiac death, target-vessel heart attack, or repeat revascularization compared with angiography guidance.
• The primary endpoint occurred in 7.7% of the imaging group versus 12.3% of the angiography group over a median of 2.1 years (hazard ratio 0.64).
• Adding intravascular imaging did not appear to increase procedure-related safety events, though procedures were longer and used slightly more contrast dye.
• The trial was conducted in South Korea, so whether results apply equally to other populations and healthcare systems is uncertain.
• Patients should discuss with their doctor whether intravascular imaging will be used during their PCI for a complex coronary lesion.

Background: Why This Research Matters

Percutaneous coronary intervention (PCI) is a common procedure used to open narrowed or blocked heart arteries. During PCI, a small balloon is inflated to widen the artery, and a mesh tube called a stent is placed to keep the artery open. Modern drug-eluting stents (stents coated with medication to prevent re-narrowing) have greatly reduced complications compared with older stent types.

However, patients with complex coronary-artery lesions still have worse outcomes after PCI than patients with simpler lesions. Complex lesions include blockages in multiple vessels, long blockages, severely calcified (hardened) blockages, and blockages at artery branch points.

During PCI, doctors can use two types of intravascular imaging to see inside the artery. These are intravascular ultrasonography (IVUS, which uses sound waves) and optical coherence tomography (OCT, which uses light waves). These imaging tools provide detailed information about the blockage and help doctors choose the right stent size, position the stent correctly, and check whether the stent is fully expanded.

A stent may not be well expanded. There may be a tear at the edge of the stent. Either problem increases the risk of stent thrombosis, which is a blood clot forming in the stent. The risk of myocardial infarction (heart attack) and repeat revascularization (needing another procedure to reopen the artery) also increases.

Previous randomized trials had shown lower rates of major adverse events with IVUS-guided PCI compared with angiography-guided PCI. However, those trials were not considered definitive because they had limited numbers of patients or included only highly selected lesion types.

Medical guidelines address this issue. These guidelines come from the American College of Cardiology and the American Heart Association. They also come from the Society for Cardiovascular Angiography and Interventions. The European Society of Cardiology and the European Association for Cardio-Thoracic Surgery also provide guidelines. These guidelines recommend that intravascular ultrasonography or OCT be considered in selected patients to optimize stent implantation.

The RENOVATE-COMPLEX-PCI trial was designed to provide definitive evidence about whether intravascular imaging-guided PCI improves clinical outcomes compared with angiography-guided PCI in patients with complex coronary-artery lesions.

How the Study Was Conducted

This was an investigator-initiated, prospective, multicenter, randomized, open-label trial conducted at 20 sites in South Korea. "Randomized" means patients were assigned to treatment groups by chance, like flipping a coin. "Open-label" means both doctors and patients knew which treatment was being used.

The trial protocol was approved by the institutional review board at each participating site. All patients provided written informed consent before randomization. A data and safety monitoring board oversaw the trial, and an independent clinical-event adjudication committee whose members were unaware of the trial-group assignments assessed all clinical events.

The funders of the trial were Abbott Vascular and Boston Scientific. These companies had no role in the trial design, in the collection, analysis, or interpretation of the data, or in the writing of the manuscript.

Which Patients Were Eligible?

Patients 19 years of age or older who were undergoing PCI for complex coronary-artery lesions were candidates for enrollment. Complex coronary-artery lesions were defined as any of the following:

• True bifurcation lesions (blockages at artery branch points) with a side-branch diameter of at least 2.5 mm
• Chronic total occlusion (a complete blockage that has been present for some time)
• Unprotected left main coronary artery disease (narrowing in the main artery supplying the left side of the heart)
• Long coronary-artery lesions requiring an expected stent length of at least 38 mm
• Multivessel PCI involving at least two major epicardial coronary arteries treated at the same time
• Lesions requiring at least three planned stents
• Lesions involving in-stent restenosis (re-narrowing inside a previously placed stent)
• Severely calcified lesions (blockages with extensive calcium deposits)
• Ostial lesions of a major epicardial coronary artery (blockages at the origin of a major artery)

Patients were excluded if they had coronary lesions not appropriate for PCI as determined by the operator. Patients were also excluded if they had cardiogenic shock (Killip class IV, a severe state where the heart cannot pump enough blood) at presentation. Patients were excluded if they had a known hypersensitivity or contraindication to aspirin, clopidogrel, prasugrel, ticagrelor, heparin, everolimus, or contrast medium. Pregnant or breast-feeding patients were also excluded.

How Were Patients Assigned to Treatment?

Eligible patients were randomly assigned in a 2:1 ratio to undergo either intravascular imaging-guided PCI or angiography-guided PCI after diagnostic coronary angiography. This means that for every two patients assigned to imaging guidance, one patient was assigned to angiography guidance.

Randomization was performed using a Web-based randomization program with permuted blocks of six. The randomization was stratified according to clinical presentation (stable ischemic heart disease or acute coronary syndrome) and participating center.

What Happened During the Procedures?

PCI was performed using standard techniques for coronary-artery-lesion preparation and stent implantation, selected at the discretion of the operator. The drug-eluting stents implanted were either biodegradable or biocompatible polymer-coated everolimus-eluting stents.

For patients assigned to the intravascular imaging group, the choice between intravascular ultrasonography and OCT was made at the operators' discretion. Intravascular imaging could be used at any time during the PCI procedure but was mandated after stent implantation to determine whether the stented segment was optimized.

Stent optimization was defined as sufficient stent expansion without major stent malapposition (stent not properly touching the vessel wall) or edge dissection (tear at the stent edge). The criteria for sufficient stent expansion included:

• A residual stenosis diameter (remaining narrowing) of less than 10% of the reference-vessel diameter for the target lesion as assessed on angiography
• A minimum stent area of more than 80% of the mean reference lumen area, or an absolute minimum stent area of more than 5.5 mm² on the basis of intravascular ultrasonography
• An absolute minimum stent area of more than 4.5 mm² on the basis of OCT for stenoses not in the left main coronary artery
• For stenoses in the left main coronary artery, an absolute minimum stent area of more than 7 mm² is required for the distal left main coronary artery. An absolute minimum stent area of more than 8 mm² is required for the proximal left main coronary artery.

Major stent malapposition was defined as an acute malapposition with a distance between the coronary-artery vessel wall and the stent of at least 0.4 mm. The length of the malapposition had to be more than 1 mm. Major edge dissection was defined as a dissection occurring within 5 mm from the edge of the stent and extending to the medial layer of the vessel. The dissection had a dissection angle of at least 60 degrees of the circumference of the vessel or a length of the dissection flap of at least 3 mm.

If stent optimization did not occur, additional dilation of the stent or additional stent implantation was recommended, and repeat evaluation on intravascular imaging was mandated.

In patients assigned to the angiography group, stent optimization was determined on the basis of angiographic findings. The stented segment was considered optimized if the residual stenosis diameter on angiography was less than 10% of the reference-vessel diameter based on visual estimation. The stented segment was also considered optimized if there was no flow-limiting coronary-artery dissection.

All angiograms and intravascular imaging data were analyzed by independent core laboratories after the completion of the PCI procedure.

What Was Measured?

The primary endpoint was target-vessel failure, defined as a composite of death from cardiac causes, target-vessel-related myocardial infarction, or clinically driven target-vessel revascularization. The primary endpoint was assessed in the intention-to-treat population (all patients who underwent randomization) during the overall trial period.

Secondary endpoints included the individual components of the primary endpoint. Secondary endpoints also included target-vessel failure without procedure-related myocardial infarction, a composite of target-vessel-related myocardial infarction or death from cardiac causes, and definite stent thrombosis.

Serious adverse events related to PCI or intravascular imaging were monitored. These included coronary perforation, emergency reintervention, congestive heart failure, cardiogenic shock, anaphylactic reaction to the contrast agent, and cardiac tamponade. These also included bleeding related to the access site or other bleeding, arterial dissection at the vascular access site, or arrhythmia.

Clinical follow-up was conducted during outpatient clinic visits scheduled at 1 month, 6 months, and 12 months and yearly thereafter. Patients unable to attend outpatient clinical visits were contacted by telephone. Cross-validation of survival status was performed using the Korean National Health Insurance database.

Statistical Analysis

The researchers estimated that a sample size of 1,620 would provide the trial with at least 90% power, at a two-sided significance level of 5%, to reject the null hypothesis. The null hypothesis was that there would be no between-group difference for the primary composite endpoint.

The annual incidence of the primary endpoint was expected to be 3.6% in the intravascular imaging group and 6.0% in the angiography group. These estimates were based on the results of previous studies. No interim analysis was planned.

All analyses were performed on an intention-to-treat basis. The primary endpoint analysis included an estimation of the cumulative-incidence function of target-vessel failure. The analysis also included a comparison of the randomized groups using the method of Fine and Gray to adjust for the potential competing risk of death from non-cardiac causes.

As a sensitivity analysis, Kaplan-Meier analyses were performed for time-to-event endpoints with treatment effects estimated using Cox proportional-hazards regression models. Subgroup analysis of the primary endpoint was performed according to the type of intravascular imaging device and clinical factors. All models were adjusted for the patient's clinical presentation and for participating centers.

Because the statistical analysis plan did not include a provision for correction for multiplicity when tests for secondary endpoints were conducted, results are reported as point estimates with 95% confidence intervals. The widths of the confidence intervals have not been adjusted for multiplicity, so they should not be used to infer definitive treatment effects for secondary endpoints.

Patient Characteristics

From May 2018 through May 2021, a total of 1,639 patients with complex coronary-artery lesions underwent randomization. Of these, 1,092 patients were assigned to undergo intravascular imaging-guided PCI, and 547 to undergo angiography-guided PCI.

Intravascular imaging devices were not used in 14 patients in the intravascular imaging group. This was owing to failure to pass the device across the lesion, failed PCI, or hemodynamic instability during the procedure. In 13 patients in the angiography group, intravascular imaging devices were used during the procedure. Patients with protocol violations were included in the analysis as part of the intention-to-treat population.

The clinical characteristics of the patients at baseline appeared to be similar in the two groups:

• Age: Average age was 65.6 ± 10.2 years overall (65.3 ± 10.3 in the imaging group and 66.0 ± 10.0 in the angiography group)
• Male sex: 1,300 patients (79.3%) overall (79.6% in the imaging group and 78.8% in the angiography group)
• Stable ischemic heart disease: 807 patients (49.2%) overall (48.7% in the imaging group and 50.3% in the angiography group)
• Acute coronary syndrome: 832 patients (50.8%) overall (51.3% in the imaging group and 49.7% in the angiography group)
• Unstable angina: 534 patients (32.6%) overall (33.1% in the imaging group and 31.6% in the angiography group)
• Acute myocardial infarction: 298 patients (18.2%) overall (18.2% in the imaging group and 18.1% in the angiography group)
• Non-STEMI: 258 patients (15.7%) overall (15.7% in the imaging group and 15.9% in the angiography group)
• STEMI: 40 patients (2.4%) overall (2.6% in the imaging group and 2.2% in the angiography group)

Medical history at baseline included:

• Hypertension: 1,005 patients (61.3%) overall (62.5% in the imaging group and 59.0% in the angiography group)
• Diabetes mellitus: 617 patients (37.6%) overall (36.1% in the imaging group and 40.8% in the angiography group)
• Insulin-treated diabetes mellitus: 51 patients (3.1%) overall (2.6% in the imaging group and 4.2% in the angiography group)
• Dyslipidemia (abnormal cholesterol levels): 840 patients (51.3%) overall (51.3% in the imaging group and 51.2% in the angiography group)
• Current smoking: 307 patients (18.7%) overall (19.4% in the imaging group and 17.4% in the angiography group)
• Chronic renal insufficiency (kidney problems): 296 patients (18.1%) overall (18.6% in the imaging group and 17.0% in the angiography group)
• Previous PCI: 395 patients (24.1%) overall (24.5% in the imaging group and 23.2% in the angiography group)
• Previous myocardial infarction: 117 patients (7.1%) overall (6.9% in the imaging group and 7.7% in the angiography group)
• Previous stroke: 112 patients (6.8%) overall (6.4% in the imaging group and 7.7% in the angiography group)
• Peripheral arterial disease: 44 patients (2.7%) overall (2.5% in the imaging group and 3.1% in the angiography group)
• Left ventricular ejection fraction (a measure of heart pumping function): 58.7 ± 11.6% overall (58.4 ± 11.9% in the imaging group and 59.3 ± 11.0% in the angiography group)

Medications at discharge were similar between groups:

• Aspirin: 1,606 patients (98.0%) overall (97.9% in the imaging group and 98.2% in the angiography group)
• P2Y12 inhibitor (antiplatelet medication): 1,603 patients (97.8%) overall (97.7% in the imaging group and 98.0% in the angiography group)
• Clopidogrel: 1,216 patients (74.2%) overall (73.2% in the imaging group and 76.2% in the angiography group)
• Ticagrelor: 209 patients (12.8%) overall (13.6% in the imaging group and 11.2% in the angiography group)
• Prasugrel: 178 patients (10.9%) overall (11.0% in the imaging group and 10.6% in the angiography group)
• Oral anticoagulant: 75 patients (4.6%) overall (4.2% in the imaging group and 5.3% in the angiography group)
• Statin: 1,567 patients (95.6%) overall (95.3% in the imaging group and 96.2% in the angiography group)
• Beta-blocker: 710 patients (43.3%) overall (42.7% in the imaging group and 44.6% in the angiography group)
• ACE inhibitor or ARB: 945 patients (57.7%) overall (57.0% in the imaging group and 59.0% in the angiography group)

Procedural Details

The characteristics of the coronary-artery target lesion and the PCI procedures appeared to be well balanced between the two groups. This included the types of complex coronary-artery lesions treated with PCI and the severity of coronary artery disease as assessed on angiography.

Types of complex coronary lesions treated:

• True bifurcation lesion: 359 patients (21.9%) overall (21.3% in the imaging group and 23.0% in the angiography group)
• Chronic total occlusion: 319 patients (19.5%) overall (20.1% in the imaging group and 18.1% in the angiography group)
• Unprotected left main coronary artery disease: 192 patients (11.7%) overall (12.6% in the imaging group and 9.9% in the angiography group)
• Diffuse long coronary-artery lesion: 898 patients (54.8%) overall (56.5% in the imaging group and 51.4% in the angiography group)
• Multivessel PCI involving at least two major coronary arteries: 622 patients (37.9%) overall (37.5% in the imaging group and 38.9% in the angiography group)
• Lesion necessitating use of at least three stents: 305 patients (18.6%) overall (19.0% in the imaging group and 17.7% in the angiography group)
• Lesion with in-stent restenosis: 236 patients (14.4%) overall (14.5% in the imaging group and 14.3% in the angiography group)
• Severely calcified lesion: 231 patients (14.1%) overall (14.4% in the imaging group and 13.5% in the angiography group)
• Ostial lesions of major coronary artery: 251 patients (15.3%) overall (16.7% in the imaging group and 12.6% in the angiography group)
• At least three complex coronary lesions: 505 patients (30.8%) overall (32.2% in the imaging group and 28.0% in the angiography group)

Number of vessels with disease:

• One vessel: 526 patients (32.1%) overall (31.3% in the imaging group and 33.6% in the angiography group)
• Two vessels: 621 patients (37.9%) overall (38.5% in the imaging group and 36.7% in the angiography group)
• Three vessels: 492 patients (30.0%) overall (30.2% in the imaging group and 29.6% in the angiography group)

Procedural characteristics:

• Total number of target lesions treated: 1.5 ± 0.7 in both groups
• Intravascular imaging device used: 1,091 of 1,639 patients (66.6%) overall; 1,078 of 1,092 (98.7%) in the imaging group and 13 of 547 (2.4%) in the angiography group
• Intravascular ultrasonography: 813 of 1,091 (74.5%) overall; 800 of 1,078 (74.2%) in the imaging group and 13 of 13 (100%) in the angiography group
• Optical coherence tomography: 278 of 1,091 (25.5%) overall; 278 of 1,078 (25.8%) in the imaging group and 0 of 13 (0%) in the angiography group
• Volume of contrast media used: 207.3 ± 116.5 ml overall (214.2 ± 118.5 ml in the imaging group and 193.7 ± 111.3 ml in the angiography group)
• Median procedural time: 65 minutes (interquartile range, 47 to 89) overall; 70 minutes (interquartile range, 51 to 95) in the imaging group and 53.5 minutes (interquartile range, 40 to 75) in the angiography group
• Procedural success: 1,613 patients (98.4%) overall (98.3% in the imaging group and 98.7% in the angiography group)

Among the 1,092 patients in the intravascular imaging group, 800 (73.3%) underwent imaging with intravascular ultrasonography and 278 (25.5%) underwent imaging with OCT. The majority of the PCI procedures were performed by means of radial-artery access, and coronary-artery lesions were treated with drug-eluting stents with procedural success in 1,613 of 1,639 patients (98.4%).

The baseline severity of the coronary-artery lesions, assessed on the basis of the minimum lumen diameter and the percent diameter stenosis, did not appear to differ between the two groups.

Use of intravascular imaging resulted in more frequent use of adjunctive balloon dilation of the stent with noncompliant balloons (ultra-high-strength balloons that accommodate high pressure without changing diameter). After PCI, the mean minimum lumen diameter was 2.8 ± 0.5 mm in the intravascular imaging group and 2.7 ± 0.5 mm in the angiography group.

Key Findings: What the Study Showed

At a median follow-up of 2.1 years (interquartile range, 1.4 to 3.0 years), the primary endpoint event had occurred in 76 patients (cumulative incidence, 7.7%) in the intravascular imaging group. The primary endpoint event had occurred in 60 patients (cumulative incidence, 12.3%) in the angiography group. This difference was statistically significant (hazard ratio, 0.64; 95% confidence interval, 0.45 to 0.89; P = 0.008).

In plain language, this means that patients in the imaging-guided group had a 36% lower relative risk of experiencing the combined primary endpoint compared with patients in the angiography-guided group. The absolute risk reduction was 4.6 percentage points (12.3% minus 7.7%).

When the individual components of the primary endpoint were examined separately:

• Death from cardiac causes: Occurred in 16 patients (cumulative incidence, 1.7%) in the intravascular imaging group and in 17 patients (cumulative incidence, 3.8%) in the angiography group
• Target-vessel-related myocardial infarction: Occurred in 38 patients (cumulative incidence, 3.7%) in the intravascular imaging group and in 30 patients (cumulative incidence, 5.6%) in the angiography group
• Clinically driven target-vessel revascularization: Occurred in 32 patients (cumulative incidence, 3.4%) in the intravascular imaging group and in 25 patients (cumulative incidence, 5.5%) in the angiography group

There were no apparent between-group differences in the incidence of procedure-related safety events.

Subgroup and Additional Analyses

The researchers performed a prespecified subgroup analysis to examine whether the benefit of intravascular imaging was consistent across different types of patients and lesions. The results of the unadjusted analysis were consistent with those of the primary analysis.

In an exploratory analysis, the cumulative incidence of the primary endpoint was 6.0% in one subgroup examined. The document also reports that definite stent thrombosis occurred in 0.1% of the intravascular imaging-guided group and 0.7% of the angiography group (hazard ratio, 0.25; 95% confidence interval, 0.02 to 2.75).

The subgroup analysis examined outcomes according to the type of intravascular imaging device used (intravascular ultrasonography versus OCT) and various clinical factors. The consistency of benefit across these subgroups supports the broad applicability of the findings.

Safety Outcomes

The trial assessed safety by monitoring serious adverse events related to PCI or intravascular imaging. These included coronary perforation, emergency reintervention, congestive heart failure, cardiogenic shock, anaphylactic reaction to the contrast agent, and cardiac tamponade. These also included bleeding related to the access site or other bleeding, arterial dissection at the vascular access site, and arrhythmia.

There were no apparent between-group differences in the incidence of procedure-related safety events. This means that adding intravascular imaging to the PCI procedure did not introduce additional safety risks compared with angiography guidance alone.

The median procedural time was longer in the intravascular imaging group (70 minutes versus 53.5 minutes). The volume of contrast media used was slightly higher in the imaging group (214.2 ml versus 193.7 ml). However, these differences did not translate into worse safety outcomes.

What This Means for Patients

This trial provides strong evidence that intravascular imaging-guided PCI improves clinical outcomes for patients with complex coronary-artery lesions compared with angiography-guided PCI. The findings are particularly important because previous trials had not been considered definitive due to limited sample size or highly selected patient populations.

For patients undergoing PCI for complex coronary lesions, the use of intravascular imaging (either intravascular ultrasonography or OCT) during the procedure may reduce the risk of:

• Death from cardiac causes (1.7% vs. 3.8% cumulative incidence)
• Target-vessel-related myocardial infarction (3.7% vs. 5.6% cumulative incidence)
• Clinically driven target-vessel revascularization (3.4% vs. 5.5% cumulative incidence)

The number needed to treat can be estimated from the data. This would prevent one primary endpoint event over 2.1 years. This is based on the absolute risk reduction of 4.6 percentage points.

The trial included a broad range of complex lesion types. These included bifurcation lesions, chronic total occlusions, unprotected left main disease, long lesions, multivessel PCI, lesions requiring multiple stents, in-stent restenosis, severely calcified lesions, and ostial lesions. This suggests that the benefits of intravascular imaging guidance apply across the spectrum of complex coronary interventions.

Both intravascular ultrasonography and OCT were used in the trial, with intravascular ultrasonography being more common (73.3% of imaging procedures) and OCT used in 25.5%. The choice between the two imaging modalities was left to the operator's discretion, and both appeared to be associated with benefit.

Limitations of the Study

Several important limitations should be considered when interpreting these results:

1. Open-label design: Both doctors and patients knew which treatment was being used. This could potentially influence decisions about subsequent treatments or procedures, although an independent committee unaware of treatment assignments assessed all clinical events.
2. Geographic limitation: The trial was conducted entirely in South Korea at 20 sites. Whether the results apply equally to other populations and healthcare systems is uncertain.
3. Operator discretion: The choice between intravascular ultrasonography and OCT was left to the operator, and the specific imaging protocols were not standardized across all sites.
4. Secondary endpoints: The statistical analysis plan did not include correction for multiple comparisons when testing secondary endpoints. Therefore, the results for individual components of the primary endpoint and other secondary endpoints should be considered exploratory and not definitive.
5. Follow-up duration: The median follow-up was 2.1 years. Longer-term outcomes beyond this period are not known.
6. Protocol violations: Fourteen patients in the intravascular imaging group did not receive imaging, and 13 patients in the angiography group did receive imaging. These patients were included in the intention-to-treat analysis.
7. Funding: The trial was supported by Abbott Vascular and Boston Scientific, although these companies had no role in trial design, data collection, analysis, interpretation, or manuscript writing.

Recommendations

Based on the findings of this trial, the following recommendations can be made for patients with complex coronary-artery lesions who are undergoing PCI:

1. Discuss imaging guidance with your doctor: If you are scheduled for PCI for a complex coronary lesion, ask your interventional cardiologist whether intravascular imaging (intravascular ultrasonography or OCT) will be used during your procedure.
2. Understand your lesion complexity: Complex lesions include blockages at branch points, chronic total occlusions, left main disease, long lesions requiring stents of at least 38 mm, multivessel disease, lesions requiring multiple stents, in-stent restenosis, severely calcified lesions, and ostial lesions.
3. Recognize the benefits: Intravascular imaging guidance during PCI for complex lesions reduces the risk of cardiac death, heart attack related to the treated vessel, and the need for repeat procedures to reopen the artery.
4. Know the safety profile: Adding intravascular imaging to PCI does not appear to increase procedure-related safety events, although it may slightly lengthen the procedure time and require slightly more contrast dye.
5. Follow medication recommendations: Nearly all patients in this trial were discharged on aspirin (98.0%), a P2Y12 inhibitor (97.8%), and a statin (95.6%). These medications are essential for preventing future cardiovascular events after PCI.
6. Attend follow-up visits: Regular follow-up at 1 month, 6 months, 12 months, and yearly thereafter is important for monitoring your heart health and detecting any problems early.

Patients should discuss the specific risks and benefits of intravascular imaging-guided PCI with their healthcare team. This discussion should take into account their individual medical history. It should also take into account the complexity of their coronary lesions and other factors.

Frequently Asked Questions

What is intravascular imaging and how is it used during a PCI procedure?

Intravascular imaging uses either sound waves (intravascular ultrasonography) or light waves (optical coherence tomography) to see inside the artery during PCI. It helps doctors choose the right stent size, position the stent correctly, and check whether the stent is fully expanded. In a trial of 1,639 patients with complex coronary lesions, imaging was mandated after stent implantation to confirm the stented segment was optimized.

What does a 36% lower relative risk mean for me?

In a trial of 1,639 patients with complex coronary lesions, those whose PCI was guided by intravascular imaging had a 36% lower relative risk of the combined endpoint of cardiac death, target-vessel heart attack, or repeat target-vessel revascularization over a median of 2.1 years. The absolute risk reduction was 4.6 percentage points. This does not mean an individual patient's risk drops by exactly 36%.

What are complex coronary-artery lesions and was I eligible for this trial?

In the trial, complex lesions included blockages at artery branch points, chronic total occlusions, unprotected left main disease, long lesions needing stents of at least 38 mm, multivessel PCI, lesions requiring at least three stents, in-stent restenosis, severely calcified lesions, and ostial lesions. Patients were 19 or older and excluded if they had cardiogenic shock or certain medication allergies.

Does adding intravascular imaging to PCI increase procedure risks?

In the trial of 1,639 patients, there were no apparent between-group differences in procedure-related safety events such as coronary perforation, emergency reintervention, heart failure, shock, contrast reaction, tamponade, bleeding, access-site dissection, or arrhythmia. However, the imaging group had a longer median procedure time (70 vs. 53.5 minutes) and slightly more contrast media used (214.2 ml vs. 193.7 ml).

What medications will I need after PCI for a complex lesion?

In the trial, nearly all patients were discharged on aspirin (98.0%), a P2Y12 inhibitor such as clopidogrel, ticagrelor, or prasugrel (97.8%), and a statin (95.6%). These medications are essential for preventing future cardiovascular events after PCI. Your own medication plan should be discussed with your healthcare team, as it depends on your individual medical history and other factors.

How long is follow-up needed after PCI for complex coronary lesions?

In the trial, clinical follow-up was scheduled at 1 month, 6 months, and 12 months, and yearly thereafter. Patients unable to attend clinic visits were contacted by telephone. The median follow-up in the trial was 2.1 years, so longer-term outcomes beyond that period are not known. Regular follow-up helps monitor heart health and detect problems early.

What is the number needed to treat and what does it mean?

This estimate comes from the absolute risk reduction of 4.6 percentage points (12.3% minus 7.7%) observed in the trial of 1,639 patients.

If I'm scheduled for PCI for a complex coronary lesion, when should I get a second opinion about whether intravascular imaging will be used?

A second opinion is reasonable when you are scheduled for PCI for a complex lesion and imaging guidance has not been discussed. Complex lesions include blockages at branch points, chronic total occlusions, left main disease, long lesions needing stents of at least 38 mm, multivessel disease, lesions requiring multiple stents, in-stent restenosis, severely calcified lesions, and ostial lesions. In a large randomized trial, imaging-guided PCI reduced the combined endpoint of cardiac death, target-vessel heart attack, or repeat revascularization from 12.3% to 7.7%. Diagnostic Detectives Network provides independent expert second opinions.

Source Information

Original Article Title: Intravascular ImagingGuided or Angiography-Guided Complex PCI NEJM 2023

DOI: 10.1056/NEJMoa2216607

Authors: J.M. Lee, K.H. Choi, Y.B. Song, J.-Y. Lee, S.-J. Lee, S.Y. Lee, S.M. Kim, K.H. Yun, J.Y. Cho, C.J. Kim, H.-S. Ahn, C.-W. Nam, H.-J. Yoon, Y.H. Park, W.S. Lee, J.-O. Jeong, P.S. Song, J.-H. Doh, S.-H. Jo, C.-H. Yoon, M.G. Kang, J.-S. Koh, K.Y. Lee, Y.-H. Lim, Y.-H. Cho, J.-M. Cho, W.J. Jang, K.-J. Chun, D. Hong, T.K. Park, J.H. Yang, S.-H. Choi, H.-C. Gwon, and J.-Y. Hahn, for the RENOVATE-COMPLEX-PCI Investigators

Publication: New England Journal of Medicine, 2023;388:1668-79

DOI: 10.1056/NEJMoa2216607

Published: March 5, 2023 (online), May 4, 2023 (print issue)

ClinicalTrials.gov Number: NCT03381872

Funding: Supported by Abbott Vascular and Boston Scientific

This patient-friendly article is based on peer-reviewed research published in the New England Journal of Medicine. The information presented here is for educational purposes and should not replace consultation with a qualified healthcare provider. Patients should discuss their individual medical situation with their doctor.