Complete or Incomplete Revascularization of Multi-Vessel CAD
How does ischemia-guided incomplete revascularization strategy with either PCI or CABG compare with complete revascularization of all the diseased segments whenever feasible? This decision is often highly individualized and incorporates significant operator bias. Nevertheless, there are criteria that I hope we can all agree on, namely: non-cardiac comorbidities, left ventricular ejection fraction, objective ischemia evidenced by stress tests, jeopardized myocardium of diseased segments, presence of viable myocardium, and anatomical complexity indicated by a moderate to high Syntax scores. The completely revascularized patients are generally younger and have less comorbidities than those selected for incomplete revascularization.
In a recent observational study from Asan Medical Center, angiographic complete revascularization was performed in 917 patients (47.9%): 40.9% with PCI and 66.9% CABG. For this group, over 5 years event rates were very similar:
- mortality was the same in both groups 8.9% PCI vs. 8.9% CABG, p=0.81
- composite of death, MI, or stroke, 12.1% PCI vs. 11.9% CABG, p=0.80
- composite of death, MI, stroke, or repeat revascularization, 22.4 PCI % vs. 24.9% CABG, p=0.32
In 19.2% patients with two or more vessels left incompletely revascularized, a greater (not statistically significant) risk of death, MI, stroke, or repeat revascularization was observed compared with the rest of the patients in the study (30.3% vs. 22.1%, p=0.079). The authors also noted that when multiple vessels were not revascularized, the five-year risk of adverse events was significantly greater in both PCI and bypass-surgery patients.
Incomplete revascularization is estimated to occur in 52% of all PCI, as reported in the ARTS trial. It is commonly defined as any non-revascularized vessel with >1.5-mm diameter and 50% to 100% stenosis. Other more stringent definitions with >2.5-mm diameter and 50% to 100% stenosis estimate the incidence of incomplete revascularization to be approximately 41%. However, it’s clear that incomplete coronary revascularization is fairly common. Incomplete revascularization occurs more frequently in PCI patients, but it is not rare in CABG populations—in the study from Kim et al (Circulation 2011), incomplete revascularization occurred in 33% of CABG patients in comparison with 59% of PCI patients (P<0.001).
Most studies have compared absolute event rates according to nonrandomized treatment strategy (incomplete versus complete revascularization), which can be meaningless, and comparing adjusted outcomes within registry populations may be challenging. It is also important to note that patients undergoing incomplete revascularization are sicker with longer procedural times, and more challenging coronary anatomy. This was highlighted by the findings form the Leipzig registry of coronary artery bypass patients. The authors of the registry also proposed the concept of “reasonable incomplete revascularization” for this challenging group of patients.
Data form Syntax, ARTS and more recently from Asan Study have linked degree of incomplete revascularization to recurrence of angina, suggesting incomplete revascularization may be important for both cardiovascular events and symptomatic status (please click on the attached digital clip). Even in the COURAGE trial, presence of significant residual ischemia (>5% ischemic myocardium) at 18 months after randomization was linked to subsequent rates of death and myocardial infarction. Another approach is to rely on FFR assessments in the cath lab prior to making multi-vessel PCI strategy decisions. Also, the procedural risks associated with compulsively trying to achieve complete revascularization with either PCI or CABG can be high, especially if it side-branches, small distal vessels etc.
Incomplete Coronary Revascularization.mov
So, a reasonable strategy towards multi-vessel revascularization with either PCI or CABG could be driven by:
- coronary anatomy: small side branches, small distal vessels, non-culprit vessels etc
- function: residual ischemic territory, viable myocardium
- physiologic gradient: FFR guided
As these suggested strategies for planning revascularization of multi-vessel CAD have not been rigorously tested in randomized trials, practice and approach may widely vary amongst interventionalists and surgeons.
So, I invite you to respond to the following question:
Which of the following you are most likely to incorporate in your decision for making a recommendation for revascularization in a patient with multi-vessel CAD:
a. coronary anatomy primarily based on coronary angiography
b. Non-invasive ischemia and viability testing
c. FFR guidance
d. IVUS guidance
e. Other (please indicate as a comment to this blog)
___
Dr Subhash Banerjee is a board certified Interventional Cardiologist and Endovascular specialist. He is the Chief of cardiology at VA North Texas Health Care System and an Assistant Professor of medicine UT Southwestern Medical Center in Dallas, TX. Dr Banerjee serves as a national proctor, teaching physicians the techniques of endovascular therapy for coronary and peripheral interventions. Dr Banerjee leads an active clinical research program focused on anti-platelet therapy, DES, and peripheral interventions. He is widely published and is funded by national peer-reviewed grants.
