twelve year old lab with a grade three heart murmur needs a dental cleaning and our vet is recommending anesthesia but the cardiac risk has me up at night, trying to understand the actual risk numbers vs the risk of leaving the dental disease untreated and i cannot find a clear answer anywhere

Roscoe is a 12 year old chocolate lab, in good health overall for his age, but he has a grade 3 out of 6 heart murmur that was first detected at his annual exam two years ago. We did an echocardiogram at the time which showed mild mitral valve disease, mild left atrial enlargement, no clinical signs of heart failure, no medication needed, just monitoring every 6 months. The murmur has held at grade 3 for the two years we have been tracking it, his exercise tolerance is normal for a senior lab, he eats well, sleeps well, no coughing or fainting. From a cardiac standpoint his cardiologist describes him as a stable B1 stage mitral valve patient, which she says is the better end of the spectrum for dogs with this finding.

The dental situation. We have been brushing his teeth nightly since he was a puppy and he has had two prior dental cleanings under anesthesia (ages 5 and 8) without issue. At his exam last month our regular vet noted significant tartar buildup on the upper molars, two teeth with visible gingival recession, and probable resorptive lesions on the carnassials based on the visual exam. She also pointed out a small swelling above his upper right canine that she is concerned could be an early dental abscess developing into the root. She is recommending a full dental cleaning under anesthesia with dental radiographs, probable extractions of the resorptive lesion teeth, and possible apicoectomy or extraction on the canine if the abscess is confirmed. Her estimate is 90 to 120 minutes of anesthesia time which is meaningful for a senior dog with cardiac disease.

What i have read and what i cannot reconcile. The published literature on anesthesia mortality in dogs with cardiac disease is wildly variable, ranging from rates that are basically equivalent to healthy dogs (about 0.1 percent) up to 2 to 3 percent for dogs with more advanced disease. Roscoes specific risk profile (B1 stage, no clinical signs, no current medication) seems to fall toward the lower end of that range but i cannot find data that breaks down the risk by exact stage. On the other side, the literature on untreated dental disease in senior dogs is grim, the inflammation drives bacteremia, the bacteremia stresses the heart, untreated dental abscesses can become facial cellulitis or osteomyelitis, and there is some evidence that dogs with significant periodontal disease have worse cardiac outcomes than dogs whose dental disease is treated. So the question is not "anesthesia risk vs no risk," it is "anesthesia risk now vs cumulative cardiac risk from ongoing dental inflammation," and the second number is harder to find in the literature.

The questions i am wrestling with before we make this decision. one, how much does the modern anesthesia protocol for cardiac patients actually reduce the risk compared to the older protocols that the published mortality data is based on, because i keep reading that monitoring and drug selection have improved significantly in the last decade but i cannot tell if the studies have caught up with the practice. two, the abscess we are watching, how urgent is it really, can we wait 6 months and reassess or does the slow inflammation cost us cardiac function in ways we cannot easily measure. three, our regular vet does dentals in house with a tech monitoring, the cardiologist mentioned a referral to a specialty hospital with a board certified anesthesiologist on site for higher risk cases would cost about three times as much, is the difference in safety actually material for a B1 stage patient or is the GP setting fine. four, the realistic outcome math if anesthesia goes badly, what does "bad outcome" look like (death on the table, post op heart failure, neurological complications) and what is the probability distribution. five, the alternative of doing nothing or doing a non anesthetic dental cleaning, are these real options or are they false comparisons that the dental community correctly dismisses. would really value input from vet anesthesiologists, cardiologists, and owners who have lived through this decision with a similar dog. i feel like i am making a coin flip with worse stakes than i can quantify and i want the math more clearly before we schedule