In smarty, strip_tags first filters the html tags and then truncate intercepts the article and uses it.

<?php echo strip_tags(“Hello <b>world!</b>”); ?>

$smarty = new Smarty; 
$smarty->assign(‘articleTitle&#39;, “Blind Woman Gets <span style=”font-family: &amp;amp;”>New Kidney</span> from Dad she Hasn&#39;t Seen in <strong>years</strong>.”); 
$smarty->display(‘index.tpl&#39;);

{$articleTitle} 
{$articleTitle|strip_tags}

Blind Woman Gets <span style=”font-family: helvetica;”>New Kidney</span> from Dad she Hasn&#39;t Seen in <strong>years</strong>. 
Blind Woman Gets New Kidney from Dad she Hasn&#39;t Seen in years.

{$article.content|truncate:35:”…”:true}