A vascular or cardiovascular medical device for placement at a site in a patient's body and for controlling pH levels at the site in the patient's body includes one or more structural components made of a biodegradable and/or bioabsorbable material, or alternatively, a coating thereon made of a biodegradable and/or bioabsorbable material. A buffering agent is provided on or in the biodegradable and/or bioabsorbable material and the buffering agent is dispersed from the biodegradable and/or bioabsorbable material in response to hydrolysis of the biodegradable and/or bioabsorbable material. Additionally, the vascular or cardiovascular medical device can include a drug that is included with the biodegradable and/or bioabsorbable material. The vascular or cardiovascular medical device can also be a stent or a valve.