Published online before print September 21, 2006, doi: 10.1161/01.STR.0000244778.32774.d5
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(Stroke. 2006;37:2656.)
© 2006 American Heart Association, Inc.
Letters to the Editor |
Response to Letter by Talelli and Ellul
Department of Neurology, University of Athens School of Medicine, Athens, Greece
Department of Clinical Therapeutics, University of Athens School of Medicine, Athens, Greece
Response:
We appreciate the interest of Drs Talelli and Ellul in our recent study evaluating the potential association between the risk of common carotid artery intima-media thickness (CCA-IMT) and the risk of stroke recurrence.1 We concur with our colleagues that CCA-IMT might be clinically useful in identifying individuals at high risk of future cerebrovascular events. We also agree that because CCA-IMT measurements are technically demanding and dependent on the level of expertise of the sonographer, the type of ultrasound device and the methodology used, they should therefore be performed under tight quality control. Indeed, our group had previously validated the precision of IMT measurements performed in our vascular laboratory.2,3 In addition, we would like also to indicate that antihypertensive medications and cholesterol-lowering therapies have been shown to exert a salutary effect on carotid artery intima-media thickening.4,5 Furthermore, recent evidence supports a genetic component in IMT variability with genetic factors contributing to 38% of the interindividual differences in IMT.6 Thus, in addition to the sonographic methodology the former 2 factors (medications and genetic variability) might have contributed to the slight discrepancies between CCA-IMT measurements documented between the 2 study populations.
The issue of defining stroke recurrence was also raised by Drs Talelli and Ellul. More specifically, recurrent events occurring within the first month after the index event were excluded from their study in order to document a more "clear" association between CCA-IMT and future events. Our group, both in the present and previous longitudinal studies identifying predictors of stroke recurrence in cohorts of patients with first-ever stroke,7 had used the standard definition of the "Stroke Data Bank" (prospective, observational study involving 4 university hospitals and the Biometry and Field Studies Branch of the National Institute of Neurological Disorders and Stroke) for documenting recurrent cerebrovascular events.8 Similar to our methodology, previous studies that assessed the relationship between CCA-IMT and recurrent cardiovascular events in patients with coronary heart disease included in their analyses patients who experienced recurrent cardiovascular events during the first month after the index event.9,10 Accordingly, we support that it might be methodologically more accurate for current investigations evaluating whether the prognostic significance of CCA-IMT on recurrent cerebrovascular events is independent of other well-documented stroke risk factors to use a definition of stroke recurrence consistent with those applied in previous studies that established independent predictors of recurrent stroke. Finally, it should be kept in mind that the observational nature of both our study and Dr Talelli’s report does not allow us to establish a causal relationship of CCA-IMT and stroke recurrence regardless of the definition of recurrent cerebrovascular events. Further, well-designed prospective randomized trials are needed to evaluate whether interventions that decrease carotid IMT may reduce the risk of recurrent stroke.
Acknowledgments
Disclosures
None.
References
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