Stenosis is narrowing, restenosis is narrowing after the lumen was widened or cleared, and you're familiar, no doubt, with the word instant. So instant restenosis means the lumen quickly narrowed again after clearing.
intracoronary bracytherapy
By forming a rigid support, the stent can prevent restenosis and reduce the need for coronary bypass surgery.
instantaneous instant coffee, instant success, ...
Yes, "instant" has a prefix. The prefix in "instant" is "in-".
Yes, it can be (instant gratification, instant coffee).The adjective is based on the noun instant, meaning a very short period of time. A similar noun is instantaneous (occurring in an instant, or immediately).
Instant messaged.
instant messaging.
Assuming you mean IMers, IM stands for Instant Message. An IMer is someone who sends instant messages. IMers are people who communicate using instant messages. Examples of instant messaging tools are Google Talk, Yahoo Instant Messenger, AOL Instant Messenger, ICQ, Adium, Pidgin, ...
The first syllable is stressed: "INstant"
Instant has 2 syllables: in stant
INstant (the first syllable)
noodles was the first instant food