Response to Letter by Touzé et al
We agree with Touzé and colleagues that coronary event rates in stroke patients without known coronary artery disease are lower than in those with coronary artery disease. We further agree that stroke outcomes are more common than coronary events in patients who have had a stroke, as we have shown in a previous analysis from the Northern Manhattan Stroke Study,1 and that limiting the assessment of outcomes to hard coronary events alone (myocardial infarction [MI] and sudden death) decreases overall event rates.
We disagree, however, that risk of MI or vascular death was “far lower” in those without baseline coronary artery disease (CAD). In fact, when we excluded patients with CAD, event rates were lower but still notably elevated, with a 5-year risk of MI or vascular death of 9.7% in those <70 years of age and without CAD.2 Furthermore, the high prevalence of CAD in our population reflects the reality that many stroke patients have comorbid CAD, as well as peripheral arterial disease. This fact is captured by the population-based design of our study and not as apparent when one examines data from clinical trials, in which exclusion criteria may limit the proportion of comorbid disease.
The National Cholesterol Education Program Adult Treatment Panel III (NCEP ATP III)3,4 provides guidelines on preventing cardiac outcomes by treating dyslipidemia but does not consider all stroke patients to be “coronary risk equivalents,” defined as those patients with a 10-year risk of MI or sudden death of at least 20% (ie, 2% annually). The results of the excellent and thorough meta-analysis of Touzé and colleagues,5 however, provides evidence that stroke patients have a risk of hard cardiac end points equivalent to that of other coronary risk equivalents: among 65 996 patients in 39 cohort studies and clinical trials, they found an absolute risk of MI of 2.2% per year. They were unable to demonstrate with certainty that all stroke patients have these high levels of risk because of the limitations inherent in their study design, but they did not find correlations between presence of history of MI and absolute risks of coronary events. New European guidelines, moreover, explicitly consider stroke outcomes together with coronary disease outcomes in determining high risk vascular categories.6 We agree with this approach both because many interventions which reduce the risk of coronary disease also reduce risk of stroke, and because many stroke patients will be at high risk of both coronary and stroke events. This was the rationale behind our suggestion to change the terminology from “coronary risk equivalents” to “coronary and stroke risk equivalents.”2 We agree with the correspondents, however, that further study in large populations with long periods of follow-up is needed to determine which stroke patients are at highest risk of coronary and other adverse vascular outcomes.
Dr Elkind received significant personal compensation from Boehringer-Ingelheim, Inc and modest compensation from BMS-Sanofi Pharmaceutical Partnership for lecturing, significant personal compensation from Merck as an expert witness, and significant research grant support from BMS-Sanofi Pharmaceutical Partnership and diaDexus, Inc. Dr Dhamoon reports no disclosures.
Dhamoon MS, Sciacca RR, Rundek T, Sacco RL, Elkind MS. Recurrent stroke and cardiac risks after first ischemic stroke: the Northern Manhattan Study. Neurology. 2006; 66: 641–646.
Dhamoon MS, Sciacca RR, Boden-Albala B, Rundek T, Sacco RL, Elkind MSV. Risk of myocardial infarction or vascular death after first ischemic stroke: The Northern Manhattan Study. Stroke. 2007; 38: 1752–1758.
Grundy SM, Cleeman JI, Merz CN, Brewer HB Jr, Clark LT, Hunninghake DB, Pasternak RC, Smith SC Jr, Stone NJ. Implications of recent clinical trials for the National Cholesterol Education Program Adult Treatment Panel III guidelines. Circulation. 2004; 110: 227–239.
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De Backer G, Ambrosioni E, Borch-Johnsen K, Brotons C, Cifkova R, Dallongeville J, Ebrahim S, Faergeman O, Graham I, Mancia G, Cats VM, Orth-Gomér K, Perk J, Pyörälä K, Rodicio JL, Sans S, Sansoy V, Sechtem U, Silber S, Thomsen T, Wood D; Third Joint Force of European and other Societies on Cardiovascular Disease and Prevention in Clinical Practice. European guidelines on cardiovascular disease prevention in clinical practice. Atherosclerosis. 2004; 173: 381–391.