Insurer Highmark Inc said on Wednesday that it reached a deal to acquire a troubled Pittsburgh health care system while offering bondholders cash payouts of 87.5 cents on the dollar. The out-of-court restructuring agreement will cut West Penn Allegheny Health System's nearly $710 million of outstanding debt and inject cash into the system, likely averting a Chapter 11 bankruptcy filing, according to a statement by Highmark and a source familiar with the matter.