What is the preferred treatment regimen for cardiovascular syphilis, specifically syphilitic ostial coronary artery disease?  

The standard treatment with benzathine pen G 2.4 MU IM, 1-3 doses at weekly intervals, depending on likely duration of syphilis, should be sufficient. Most likely there is no need for especially high dose penicillin therapy. I can understand a theoretical rationale for it, for urgent or potentially ...