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Where are we with revascularization procedures medical therapy in 2010?
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After several decades associated with an evolving landscape for coronary revascularization and medical therapy, some clarity is beginning to emerge relative to appropriate expectations for patient management.
The short- and intermediate-term morbidity and mortality benefits of adding prompt revascularization by percutaneous coronary intervention to contemporary medical therapy have been established in high-risk patients with acute ischemic syndromes (eg, STEMI). Although some debate remains relative to early PCI use in lower risk acute ischemic syndrome patients, an early invasive approach is still favored by many, including myself, for these patients also.
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Among patients with chronic ischemic syndromes, the results of the BARI 2D trial and a meta-analysis of 17 other trials document similar efficacy of PCI and optimal medical therapy in regard to short and intermediate-term mortality and MI risks. However, in high-risk diabetic patients, prompt CABG improves survival vs. optimal medical therapy alone, particularly when diabetes is treated with insulin sensitizing agents.
Perhaps overshadowed by the similarity in mortality and MI outcomes comparing PCI and optimal medical therapy is the fact that revascularization, by either PCI or CABG, generally results in greater symptom control and ischemia reduction than drug therapy alone. A meta-analysis of 14 trials from 1992 to 2007 has further confirmed that PCI is associated with greater freedom from angina compared with medical therapy, but interestingly, this benefit appears to be attenuated in the more contemporary studies. Such attenuation among patients treated by PCI may be related to greater use of evidence-based medications in the more contemporary trials, changing characteristics of the disease, and/or changing characteristics of the patients referred for PCI (eg, more severe or extensive disease). Thus, in patients with chronic ischemic syndromes, it seems that deferring PCI does not result in excess MI or mortality but will likely be at the expense of less symptom reduction and reduced quality of life. However, among those with more advanced disease, deferring CABG is likely to result in an increase in adverse outcomes, particularly when the patient has diabetes.
New clinical trial results also raise important questions about other medical management questions among diabetics and nondiabetics. The benefits of additional drugs to reach lower BP goals, glycohemoglobin <7%, specific glucose-lowering drugs, and/or raising HDL cholesterol, while becoming clearer, are still not completely resolved.
Based on the randomized ACCORD trial, and supported by findings from the observational extended follow-up of the INVEST diabetes cohort, among diabetes patients at high risk for CV events, targeting a systolic BP <120 mm Hg (as compared with <140 mm Hg) does not reduce fatal and nonfatal CV events. While there was a small reduction in stroke risk, it was at the expense of an increase in drug and/or low BP-related adverse experiences. Intensive therapy targeting normal glycated hemoglobin levels was associated with increased mortality and did not significantly reduce major CV events. Intensive drug therapy did not reduce risks of advanced microvascular outcomes, but delayed onset of albuminuria, some measures of eye complications, and neuropathy, but these benefits must be weighed against the increase in total and CV-related mortality, increased weight gain, and high risk for severe hypoglycemia. Intensive glycemic control and intensive dyslipidemia treatment, but not intensive BP control, were associated with reduced progression of retinopathy.
The BARI 2D trial focused on advanced CAD in established diabetic patients, but whether newly incident diabetics should be screened for subclinical atherosclerosis and treated aggressively with drug therapy as in BARI 2D is unclear. There is still uncertainty whether these strategies will provide further benefit in reducing long-term morbidity and mortality.
Carl J. Pepine, MD, is Professor of Medicine, Division of Cardiovascular Medicine at the University of Florida, Gainesville. He is also Chief Medical Editor of Cardiology Today.
For more information:
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