Incomplete Revascularization Linked With Increased MACE in Subsequent Noncardiac Surgery

NEW ORLEANS, LA—Incomplete coronary revascularization is associated with an increased risk of major adverse cardiac events, particularly an increased risk of MI, among patients who later go on to have noncardiac surgery, a new analysis shows.

Individuals with incomplete revascularization—defined as a residual stenosis of ≥ 50% in the left main coronary artery or ≥ 70% in another major epicardial coronary artery—had a 19% higher risk of major adverse cardiovascular events at 30 days compared with those with complete revascularization (P = 0.05). The difference was driven by a 37% increased risk of MI (P = 0.01).

Presented today at the American Heart Association Scientific Sessions 2016, investigators point out that for each vessel left with residual stenosis, there was a 17% higher risk of postoperative MI (P < 0.001).

“We do see people in the cath lab who come through and we will only treat a single vessel,” said Javier Valle, MD (University of Colorado School of Medicine, Aurora), one of the study investigators. “I think what ends up happening is that the patient might be asymptomatic, but they still have unrevascularized territory. When they go to the operating room, that provides an undue stress on that territory. That’s a reasonable thought coming from our results. We can’t prove that based on our study, but it’s one of the definite hypotheses we have for explaining our data.”

The study, which was published simultaneously in the Journal of the American College of Cardiology, included 12,486 patients undergoing PCI and subsequent noncardiac surgery in the US Department of Veterans Affairs (VA) healthcare system. Of these, 35% received incomplete revascularization.

To TCTMD, Valle noted that the CARP (Coronary Artery Revascularization Prophylaxis) trial, which included 5,859 patients scheduled for vascular surgery who underwent coronary revascularization prior to surgery, was a negative study published more than a decade ago. In CARP, coronary revascularization did not alter long-term clinical outcomes after vascular surgery and based on those findings, the consensus had been to minimize coronary revascularization among patients with stable cardiac symptoms before elective surgery.

However, residual ischemia in patients with stable coronary disease is a risk factor for long-term adverse cardiovascular events, and patients treated with complete revascularization—either PCI or CABG—have lower cardiovascular event rates, according to the researchers.   

Regarding their findings, Valle said they suspected that incomplete revascularization might be associated with an increased risk of major adverse cardiovascular events after noncardiac surgery. The stepwise association between the number of vessels left with residual stenosis and the risk of MI strengthened the relationship in their view. 

In their analysis, the researchers observed a significant interaction with the timing of noncardiac surgery. For those who underwent noncardiac surgery fewer than 6 weeks following PCI, patients incompletely revascularized had a 84% higher risk of postoperative MI compared with those who received complete revascularization. There was no increase in MI risk observed among those who underwent subsequent surgery beyond 6 weeks after PCI.

Valle said that approximately one in five patients who receive PCI will require some form of noncardiac surgery within 2 years, at least in the VA healthcare system. For these patients undergoing surgery, it would make sense to be “proactive and little more vigilant about the preoperative evaluation” before sending patients to the operating room, said Valle.  

Secondly, if the patient has had PCI within the past 6 weeks, it would also make sense to question whether surgery needs to happen. If the operation can be delayed, physicians can ensure that medical therapy is optimized and the patient has undergone comprehensive preoperative testing, said Valle.

One of the study limitations is that investigators were unable to determine the type of MIs that occurred following surgery. For example, they do not know if the increased risk is the result of troponin elevations or plaque ruptures and stent thromboses. “But I don’t think it’s a stretch to imagine that a lot of these events are basically supply and demand mismatches in the setting of a stenosis,” said Valle.