{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,11,1]],"date-time":"2025-11-01T05:26:50Z","timestamp":1761974810199,"version":"3.40.4"},"reference-count":2,"publisher":"S. Karger AG","issue":"1","license":[{"start":{"date-parts":[[2003,1,1]],"date-time":"2003-01-01T00:00:00Z","timestamp":1041379200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/www.karger.com\/Services\/SiteLicenses"},{"start":{"date-parts":[[2003,1,1]],"date-time":"2003-01-01T00:00:00Z","timestamp":1041379200000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/www.karger.com\/Services\/SiteLicenses"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Cerebrovasc Dis"],"published-print":{"date-parts":[[2003]]},"abstract":"<jats:p>&lt;i&gt;Background:&lt;\/i&gt; Amplitude responsiveness of cerebral blood flow velocity (CBFV) to CO&lt;sub&gt;2&lt;\/sub&gt; is an established test of cerebrovascular reserve capacity. We aimed to analyze the time course of CBFV during CO&lt;sub&gt;2 &lt;\/sub&gt;reactivity testing in patients with severe carotid stenosis. &lt;i&gt;Methods:&lt;\/i&gt; 87 patients were assigned to three different groups according to the degree of stenosis (A 75\u201389%, B 90\u201394%, C 95\u2013100%) and CBFV dynamics was assessed by transcranial Doppler sonography during hypercapnia induced by inhalation of 7% CO&lt;sub&gt;2. &lt;\/sub&gt;Time constants for the duration of CBFV and the end-tidal CO&lt;sub&gt;2 &lt;\/sub&gt;partial pressure (Pet&lt;sub&gt;CO2&lt;\/sub&gt;) increase and decrease were calculated. In addition, time delays between subsequent changes of Pet&lt;sub&gt;CO2&lt;\/sub&gt; and CBFV during on- and offset of hypercapnia were determined. &lt;i&gt;Results:&lt;\/i&gt; There was a significant reduction of conventional CO&lt;sub&gt;2&lt;\/sub&gt; reactivity on the side ipsilateral to the stenosis in all groups. Time constants of CBFV showed no major differences between ipsi- and contralateral sides or between different groups. The off delay between the decrease in Pet&lt;sub&gt;CO2&lt;\/sub&gt; and the consequent decrease in CBFV was the only out of 6 different dynamic parameters which significantly differentiated critical stenosis and occlusion from severe stenosis. Retest variability showed a highly significant correlation. &lt;i&gt;Conclusions:&lt;\/i&gt; Analysis of the dynamic CBFV response during the applied CO&lt;sub&gt;2&lt;\/sub&gt; inhalation protocol revealed a significant and reproducible delay parameter which has power to detect cerebral hemodynamic compromise in patients with carotid artery stenosis similar to the conventional CO&lt;sub&gt;2 &lt;\/sub&gt;reactivity parameter.<\/jats:p>","DOI":"10.1159\/000070109","type":"journal-article","created":{"date-parts":[[2003,5,28]],"date-time":"2003-05-28T07:40:46Z","timestamp":1054107646000},"page":"14-20","source":"Crossref","is-referenced-by-count":6,"title":["Time Delay as a Parameter for Cerebrovascular Reactivity in Patients with Severe Carotid Stenosis"],"prefix":"10.1159","volume":"16","author":[{"given":"A.","family":"Hetzel","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"B.","family":"Guschlbauer","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"M.","family":"Reinhard","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"127","published-online":{"date-parts":[[2003,5,16]]},"reference":[{"key":"ref1","doi-asserted-by":"publisher","DOI":"10.1001\/jama.283.16.2122"},{"key":"ref2","doi-asserted-by":"publisher","DOI":"10.1159\/000015944"}],"container-title":["Cerebrovascular Diseases"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.karger.com\/Article\/Pdf\/70109","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/www.karger.com\/Article\/Pdf\/70109","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,4,24]],"date-time":"2025-04-24T03:17:19Z","timestamp":1745464639000},"score":1,"resource":{"primary":{"URL":"https:\/\/karger.com\/article\/doi\/10.1159\/000070109"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2003]]},"references-count":2,"journal-issue":{"issue":"1","published-online":{"date-parts":[[2003,5,1]]}},"URL":"https:\/\/doi.org\/10.1159\/000070109","archive":["Portico"],"relation":{},"ISSN":["1015-9770","1421-9786"],"issn-type":[{"type":"print","value":"1015-9770"},{"type":"electronic","value":"1421-9786"}],"subject":[],"published":{"date-parts":[[2003]]}}}