** Shares in Carmat ALCAR.PA plunge as much as 70.6% to their lowest price ever after the French artificial heart maker said it was at a risk of insolvency by the end of June
** Carmat said it was "facing a critical financial situation" and that it needed about 3.5 million euros to avoid insolvency
** "Financing difficulties are putting Carmat in a very difficult cash position. Even though the company is making significant progress on the operational front (...) all this progress could be wiped out in the absence of a very short-term solution," Portzamparc analysts say in a note
** Carmat added it was actively exploring financing options and would launch a campaign seeking donations through an online platform
** Shares in Carmat will see their worst day ever if losses hold; stock down around 64% at 0910 GMT, having hit an all-time low of 0.23 euros earlier in the session
(Reporting by Mathias de Rozario in Gdansk)
((mathias.derozario@thomsonreuters.com;))