NStar (NST) (ThOR) (MRGE) (NXTM) Upgraded

NStar (NYSE: NST), Thoratec (NASDAQ: THOR), Merge Healthcare Inc (NASDAQ: MRGE) and Nxstage Medical (NASDAQ: NXTM) upgraded by analysts.

Merge Healthcare Inc. (MRGE) was upgraded by Robert W. Baird from a “Neutral” rating to an “Outperform” rating. They have a price target of $8.00 on the company, up from $6.00.

NStar (NST) was upgraded by ISI Group from a “Sell” rating to a “Hold” rating.

Nxstage Medical (NXTM) was upgraded by Rodman & Renshaw from an “Underperform” rating to a “Market Perform” rating.

Thoratec (THOR) was upgraded by Wedbush from an “Underperform” rating to a “Neutral” rating. They have a price target of $33.00 on the company.

Losers (CENX) (OPEN) (NXTM) (CTCM) (HMPRD) on May 4

Century Aluminum Company (NASDAQ:CENX), OpenTable Inc (NASDAQ:OPEN), NxStage Medical, Inc. (NASDAQ:NXTM), CTC Media, Inc. (NASDAQ:CTCM) and Hampton Roads Bankshares Inc (HMPRD) were among the big losers on Wednesday, May 4.

Century Aluminum Company (CENX) closed at $16.52, plunging $3.22, or 16.31 percent. Missing revenue and earnings estimates in the latest quarter was the major catalyst.

OpenTable Inc (OPEN) closed Wednesday at $89.35, dropping $15.65, or 14.90 percent. The switching of CEOs was behind driving the share price down.

NxStage Medical, Inc. (NXTM) closed the trading session at $20.43, falling $3.25, or 13.76 percent. Trading volume was about 6 times the daily 3-month average.

CTC Media, Inc. (CTCM) ended the day at $20.00, down $2.69, or 11.86 percent. Shares dropped after the company reported non-GAAP EPS of $0.16, missing estimates by 1 cent.

Hampton Roads Bankshares Inc (HMPRD) closed Wednesday at $11.72, dropping $1.56, or 11.75 percent. Volume was just under 5 times the daily 3-month average. It traded in a range of $11.62 - $12.99 on the day.

NxStage Medical's (NASDAQ:NXTM) System One Driven by Quality of Life

Citing patients' response to using NxStage Medical's (NASDAQ:NXTM) System One, which is a home dialysis system, Canaccord sees adoption of System One continuing to grow.

Canaccord says, "We reiterate our rating and Best Idea designation on NxStage Medical following our System One patient dinner as it reconfirmed the large unmet clinical need the treatment fills. Quality of life (QoL) improvement seems to be the biggest driver of adoption and patient retention. We continue to believe that with the improved reimbursement landscape in 2011 and clinical data support, there is an increasing awareness and focus on performing dialysis in the home, which bodes well for the adoption of System One."

Canaccord Genuity maintains a "Buy" rating on NxStage Medical (NXTM), which closed Monday at $24.56, gaining $0.44, or 1.82 percent. Canaccord has a price target on $29 on NxStage, boosting it from $27.

Thoratec (NASDAQ:THOR), NxStage Medical (NASDAQ:NXTM) Top Medical Devices Ideas in 2011 for Canaccord

Medical devices analysts Jason Mills and William Plavonic, from Canaccord Genuity, released their top two companies for 2011.

They are:

A) Thoratec (NASDAQ:THOR) Mr. Mills recommends investors accumulate shares of THOR at current levels for the following reasons: 1) We believe THOR's value is much higher than current trading levels based on its earnings potential in 2011 and 2012; 2) The huge untapped patient population (namely the “DT” cohort); 3) The potential for its new product pipeline to produce further advancements in durability, size and full-implantability, which could help mitigate the Street's expectation of massive share loss (i.e. 70-80% by 2015; we continue to model THOR with a 51% overall market share in 2015); and 4) Our continued belief the LVAD market will continue to grow much faster than most if not all major med-tech markets over the next 5+ years. We also note that THOR has a sizeable cash position (>$450M), with which it can diversify its product portfolio and/or buy back shares, which it has done in the past.

B) NxStage Medical (NASDAQ:NXTM) - NxStage Medical remains Mr. Plavonic’s top growth name entering 2011 for the following reasons: 1) The company has a great deal of momentum considering the improved reimbursement landscape; 2) Additional positive data released from the NIDDK study; 3) Overall increased attention toward performing more dialysis in the home; and 4) Of note, the Q3/10 results represented the fourth consecutive quarter of very strong home hemodialysis results and the eighth consecutive quarter of outperformance for home hemodialysis growth.

NxStage Medical closed Wednesday at $23.61, up $0.02, or 0.08 percent. Thoratec closed at $27.66, down $0.27, or 0.97 percent.