Following are the major surgeries Prime Minister, Manmohan Singh [Images] has undergone:

1990: Singh underwent a Coronary Artery Bypass Surgery in the United Kingdom.

2004: Angioplasty was conducted on Prime Minister to clear the clogged arteries.

October 14, 2005:  He underwent surgery for carpal tunnel syndrome on right wrist.

September 15, 2007: Surgery for benign enlargement of the prostate gland at AIIMS.

May 25, 2008: Prime Minister Manmohan Singh underwent a cataract operation at AIIMS.

'No room for concern'

The bypass surgery on Prime Minister Manmohan Singh on Saturday does not call for any undue concern, Dr Upendra Kaul, a leading cardiologist said on Friday night.

"I don't think there is room for any concern or problem," Dr Kaul, Executive Director, Cardiology at Fortis and Escorts hospitals, said, adding that on Saturday 'everyone will be heaving a sigh of relief.

"Any person who has undergone bypass surgery eight to ten years ago runs a chance of having the problem again and one of the solutions is repeat bypass surgery if there are multiple blockages. It is done regularly and it needs a little more care," he said.

The cardiologist said Dr Singh may require three or four grafts, 'which should not be a problem'.

The 76-year-old prime minister was admitted to the All India Institute of Medical Sciences on Friday and will undergo a coronary bypass surgery for removal of blockages in his heart vessels.