It is allowed to have a heart valve transplant from a pig if necessity requires the use of this organ to cure a patient and there is no other alternative. Also, it is a condition that a competent and trustworthy Muslim physician make this decision. Necessity overrules prohibitions in the juridical rule.
Sheikh Yusuf Al-Qaradawi, who states: “Basically, transplanting an organ from an impure animal such as a pig to a human body must not be resorted to save in case of necessity. It should be considered that what is rendered permissible due to necessity should be estimated only according to what alleviates the hardship in every case. Also, this should be estimated by reliable and trustworthy Muslim physicians.
In such case, it can be argued that what is forbidden in respect to pigs is consuming their meat as stated in the Qur’an. However, transplanting a part from it to a human body is not a consumption but falls under the category of making use of this part. The Prophet (peace and blessings be upon him) has permitted the use of some part of it, i.e. its skin. The prohibition of eating the meat of pigs followed prohibiting the meat of dead animals. Then, if it is permitted to make use of some part of dead animals, then it is also permissible, by analogy, to make use of pigs in things other than consumption. Al-Bukhari and Muslim reported on the authority of `Abdullah ibn `Abbas that once Allah’s Messenger passed by a dead sheep and said to the people, “Wouldn’t you benefit by its skin?” The people replied that it was dead. The Prophet said, “But only its eating is illegal.”
Moreover, it may be argued that pigs are impure or najis, then how can we implant part of it in the body of a Muslim? Here, I say that what is forbidden according to Shari`ah is that impurities come in contact with one’s apparent body and that it be apparently [outwardly] contaminated with it. As for what is inside the body, there is no evidence to prevent it. This is because there exist a lot of impurities such as urine, stool, blood, and other discharges inside the human body, yet man is allowed to pray, recite the Qur’an, make tawaf around the Ka`bah, etc., with these impurities inside. These impurities do not affect his acts of worship, as the rulings related to impurities are not applicable regarding those inside the human body.”
The prominent Muslim scholar, Mufti Ebrahim Desai, adds: “If there is almost certain fear of loss of life or danger of losing the limb or organ, and the replacement is only found in haram animals or in permissible animals (which can be eaten) but not slaughtered according to Islamic rites, then use of such a component will be permissible. However, if there is no imminent danger of loss of life, then it will not be permissible to use anything from the pig.”
Sheikh ibn Baz, the late eminent Muslim scholar and former Mufti of Saudi Arabia was also of the view that “transplanting an organ from an animal lawful for Muslim consumption and which has been slaughtered or an animal not lawful for Muslim consumption, the latter under necessity, is permissible.” (Muqarrat Majlis al-Majma` al Fiqhi al Islami, Makkah, 1405/1985, page 147)