Okay, that title isn't really fair. The Democratic controlled Senate actually voted against repealing the entire Health Care Reform Act.
But separately, the Senate voted to repeal the new 1099-reporting rules that were enacted as part of health care reform last year. The repeal provision is a Democratic amendment to the FAA re-authorization bill; there was no vote on a similar proposal from Republicans.
The change in the 1099 rules was enacted as part of the funding for health care reform. The amendment is kind of vague on how the cost of repeal will be offset in the budget, merely authorizing the Office of Management and Budget to cut unnecessary and unobligated spending, with an exemption for administrative costs at the Social Security Administration.
House leadership and the White House have already indicated they favor repeal, and the FAA bill itself, with $6billion in new spending on airport construction, is itself popular among lawmakers.