My beloved Maine Coon, Princess, was diagnosed with lung cancer last spring. I sought the best medical care for her, thinking that VPI would pay a reasonable portion of the charges. She had a respiratory crisis(my carrier-avoidant baby had climbed into it, so I rushed her to a specialty veterinary clinic), knowing she was in dire straits. She required oxygen therapy overnight and for most of the following morning. Complicating factors included tachycardia and cardiomyopathy. No previous veterinarian had diagnosed either condition. Well, VPI denied those specific charges,citing pre-existing(!)conditions. Tell me, what creature wouldn't have tachycardia, being terrified and unable to breathe? And the cardiomyopathy was secondary to the cancer, not a hereditary condition. I ended up about $6,000 in debt, after VPI's paltry payments. On the plus side, the customer service representatives were very sympathetic and helpful.
Age of Pet