Shares of Boston Scientific (NYSE:BSX) are down nearly 5% this morning after the medical device maker reported a 54.7% decline in 4th-quarter profits – despite a swing to black ink for the full year.

The Natick, Mass.-based firm reported profits of $107 million, or 7 cents per diluted share, on sales of $1.85 billion for the 3 months ended Dec. 31, 2011. That compares with profits of $236 million, or 8 cents diluted EPS, on sales of $2.0 billion during the same period in 2010 – a top-line decline of 7.7%.

For the full year, Boston Scientific logged profits of $441 million, or 29 cents diluted EPS, on sales of $7.62 billion. That compares with losses of $1.07 billion, or 70 cents diluted EPS, on sales of $7.81 billion during 2010 – meaning 2011 sales were down 2.4%.

The news sent BSX shares down 4.8% to $5.80 as of about 10 this morning, despite adjusted earnings that beat Wall Street’s expectations. Excluding 1-time items, Q$ adjusted EPS reached 13 cents, crushing the 8 cents expected by analysts on The Street. Full-year adjusted EPS were 67 cents, again far above the 44 cents expected on The Street.

“Although we recognize the ongoing challenges of today’s environment, we continue to make progress with new product introductions, cost-saving initiatives and a strengthened presence in emerging markets,” CEO Hank Kucheman said in prepared remarks.

Lower sales for BSX’s workhorse interventional cardiology business, which includes its coronary stents operation, helped fuel the declines. The division posted revenues of $594 million during the 4th quarter, down 7.3%, and $2.50 billion for the full year, down 4.1%.

The ongoing CRM slump also played a part. Fourth-quarter CRM sales were $482 million, down 15.5%, and full-year sales dropped by 4.3% to $2.09 billion.

Boston Scientific said it expects Q1 sales of between $1.83 billion to $1.9 billion and EPS of 2 cents to 5 cents. For the full year, sales are forecast to run between $7.3 billion and $7.7 billion, with EPS of 25 cents to 38 cents.