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Coronary revascularization: A focus on symptoms, ischemia and biology
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Indications for PCI for coronary revascularization continue to evolve. As current technology — principally, advanced drug-eluting stents and adjunctive medical treatment — continues to improve, the potential safe application of PCI in the management of coronary vascular disease has expanded.
However, there remains a disconnect between the recognized symptomatic and survival benefits for high-risk patients undergoing CABG compared with the symptomatic but not survival benefits accrued from PCI, most often in less severe anatomic circumstances compared with intensive medical therapy.
George W.
Vetrovec
If revascularization is beneficial for CABG compared with medical therapy, why not for PCI? Possible reasons for these differences are multifactorial: (1) less complete revascularization with PCI; (2) bypass conduits that “protect” longer segments of the diseased coronary artery than usually occurs with stents; (3) overall higher-risk surgical patients that potentially magnify small benefits to clinical outcome; and (4) compared with CABG, there is more frequent recurrent ischemia with PCI because of clinically asymptomatic restenosis. Furthermore, a recently recognized fact is that the morbidity benefits of PCI accrue most clearly in patients with documented flow-limiting lesions compared with visual angiographic assessment, a fact that seems less important in defining favorable late outcomes for patients undergoing CABG compared with PCI or intensive medical therapy. Despite decades of experience, procedure refinement and research, there are still significant gaps in our knowledge.
A focus on limiting the use of PCI
As a consequence of these facts and a concern that PCI has been utilized too often for “borderline” significant lesions, there has been a major focus on limiting the use of PCI to only patients with documented ischemia-producing lesions, severe symptoms and failure of intensive medical management. Such a conservative approach, although potentially cost saving, ignores important social and scientific issues discussed below.
First, symptomatic patients have a right, with proper information and explanation, to decide whether they prefer PCI, CABG or intensive antianginal medical therapy for symptomatic angina control. Continued symptoms, adverse effects and medication intolerance can occur with medical therapy; complications of CABG or PCI with restenosis/stent thrombosis also can occur. We are entering a time when patient-imposed decisions, not doctor-imposed decisions, will be the hallmark of modern American medical care. So we must begin to incorporate this strategy into our revascularization decision making. Such an approach will require surgeons, interventionalists and primary care physicians to proactively and honestly educate patients as to the pros and cons of markedly varied management strategies. Importantly, it must be emphasized that individual patient decisions in a patient-centered strategy need to be respected even if patients choose an invasive, intensive strategy after appropriate education. “Patient-centered care” should not be synonymous with the least expensive, provided patients have been factually instructed.
Second, potential late morbidity and mortality benefits for PCI based on ischemia and plaque biology may be coming under better focus. For example, the FAME II trial demonstrated that if one makes decisions based on documented ischemia-producing lesions, the benefits of PCI exceed watchful waiting. During the past 3 decades, the debate over the benefits of eliminating ischemia has tended to support such an approach. FAME II appears to affirm the benefits of eliminating ischemia, as did the ischemia substudy in the COURAGE trial and the much earlier ACIP pilot trial, all of which demonstrated the benefits of revascularization. Underlying ischemia appears to increase cardiac risk, whereas the elimination of ischemia most often is associated with benefit.
Regarding biology, the recently presented results of the PRAMI study are intriguing. PRAMI demonstrated a late morbidity benefit for patients with STEMI who had complete revascularization without regard for ischemia in the setting of the initial procedure. Whether the investigators’ acute timing of revascularization is correct, one can suspect that in this specialized population associated with a highly inflammatory and thrombotic milieu, complete revascularization is potentially beneficial to prevent early “secondary” lesion-associated events.
Thus, morbidity outcome benefits of PCI may occur but must be focused to specific populations. In stable angina, the emphasis should be on eliminating ischemia. In STEMI patients, complete revascularization may require treating a broader set of lesions because of the local plaque and systemic biologic differential risk in this acute setting.
Let me be clear. I am not advocating “cosmetic PCI” for every bump in an artery or open season for the use of PCI for all coronary lesions. We must not advocate or utilize such an approach, and, theoretically, our failure to better define lesions by their individual potential risk may be the reason PCI has never shown a late event-related benefit. We attempted to adopt a single-therapy-fits-all approach. However, the response to perceived overuse of PCI must be tempered with the recognition that there are patient subgroups that preferentially benefit from PCI beyond symptomatic angina control. While not totally defined, we must keep an open mind and not overreact while ongoing science continues to evolve refining the risk and benefit of PCI.
Improved vigilance, understanding
In summary, PCI continues to technically advance, conferring a need to remain vigilant to improving outcomes on the basis of technology alone. Concomitant with technical improvements, our understanding of the importance of ischemia and its elimination by PCI must continue to be a focus of our practice and ongoing research. In addition, the greater understanding and application of the concepts of systemic inflammation and plaque biology into our utilization of PCI will be critical to better define lesions based on their ischemic and infarction potential.
As we enter a time of medical social change with a greater emphasis on patient desires, we must improve our patient education, communication and combined professional decision making while demanding that patient desires be recognized as an integral part of decision making regardless of patient choice.
PCI continues to play an important role in the management of CAD. Inappropriate PCI use is unacceptable, but overrestricting percutaneous revascularization denies many appropriately selected patients the potential morbidity benefits of PCI.
Disclosure: Vetrovec reports no relevant financial disclosures.