HealthTap Chief Executive Officer Ron Gutman believes paying the doctor a visit is expensive and time-consuming. So why not bring the doctor to the patient – digitally? On Wednesday, the Palo Alto-based startup, which is backed by investor Vinod Khosla, introduced a virtual-consult service called HealthTap Prime. Consumers can opt to pay $99 a month to text or video conference with a physician, online or via a smartphone. It remains to be seen whether patients will be willing to pay out-of-pocket for HealthTap’s service, which is not covered by the largest insurers.