PCI of a Last Remaining Patent Vessel Is Rare and Risky, UK Data Confirm

Patients who undergo PCI of a last remaining patent coronary artery make up an especially high-risk group with poorer outcomes compared with those who have other PCI procedures, data from the British Cardiovascular Intervention Society (BCIS) show.

In particular, these patients—who accounted for 0.48% of PCIs during the study period—have substantially higher risks of mortality or MACE during the initial hospitalization, as well as greater risks of dying within 30 days and 1 year, even after accounting for baseline differences.

There were a number of surprising findings to come out of the research, including how little literature there is on PCI of a last remaining patent vessel and how infrequently these patients are treated, senior author Mamas Mamas, BMBCh, DPhil (Keele University, Stoke-on-Trent, England), told TCTMD. The details were published recently online in Circulation: Cardiovascular Interventions.

Considering how sick these patients were overall, the low rates of intravascular imaging (6.6%), mechanical circulatory support (14.0%), and complete revascularization (2.3%) were a surprise, too, he said. “I think these sorts of cases require upfront planning, number one, and number two, a state-of-the-art procedure to make sure that the result of your PCI is the best that you can get it, because if there’s a complication or an event down the line from an inadequate procedure, this will be catastrophic for the patient.”

We absolutely should be doing gold-standard PCI in these patients and if we can’t do gold standard PCI, refer to someone that can. Mamas Mamas

Commenting for TCTMD, Arasi Maran, MD (Medical University of South Carolina, Charleston), said the analysis confirms what interventional cardiologists already knew—that patients with a single remaining patent artery are older, sicker, and at higher risk for poor outcomes than others undergoing PCI. Maran said the study also highlights the fact that cardiologists often avoid taking action on the tougher cases like chronic total occlusions (CTOs).

“Why do these patients have so many CTOs that are untreated, [leaving them] with only one remaining blood vessel?” she asked. With advancements in PCI technology, including mechanical circulatory support (MCS), operators should have been treating more and more of these patients over time, but that wasn’t seen, she said. “The fact that the volumes have stayed steady means that maybe we are not evolving as fast as we should.”

One of the Highest-Risk CHIP Procedures

A “complex higher-risk and indicated patient” (CHIP) population for PCI has been defined relatively recently, and one of the criteria is revascularization of a last remaining patent vessel (when the other main epicardial arteries are completely blocked), Mamas said. Because of how infrequently such procedures are performed, however, there are few data available to provide insights into this population.

In the current study, the investigators—led by Ahmad Shoaib, MD, and Muhammad Rashid, PhD (both Keele University)—dug into the BCIS database to look at PCIs performed in England and Wales between 2007 and 2014. The analysis included 2,432 patients who received an intervention in a last remaining patent vessel (LRPV) and 506,691 who underwent another type of PCI. They were followed for a median of 3.7 years.

Patients in the LRPV group were older on average, were less likely to be female, had a heavier burden of comorbidities, and were more likely to have moderate-to-severe LV systolic dysfunction. They were also more likely be in cardiogenic shock at presentation and to present with STEMI and NSTEMI rather than unstable angina.

There were no differences between groups in use of intracoronary imaging, although use of MCS, rotational atherectomy, laser angioplasty, penetration/microcatheters, and mechanical ventilator support was more frequent in the LRPV group.

On multivariate analysis, outcomes—with the exception of in-hospital stroke and reintervention—were worse in the LRPV group compared with other types of PCI. Findings were similar in a propensity score-matched analysis.

Clinical Outcomes After Multivariate Adjustment

^*In-hospital mortality, in-hospital MI, or TVR.

In sensitivity analyses, the results were similar when shock patients were excluded and regardless of which major epicardial coronary artery was treated and whether complete revascularization was performed.^*In-hospital mortality, in-hospital MI, or TVR.

Maran told TCTMD she was disappointed the LRPV patients were compared with other patients undergoing other PCI procedures rather than similar LRPV patients treated medically, which she believes would have been a fairer comparison.

Improving PCI in the LRPV Group

Mamas expressed surprise at how PCI was performed in the LRPV group, with intravascular imaging rarely used. “If you’re doing a high-risk PCI in someone’s last remaining patent vessel, the fact that only a minority of cases—7%—used intravascular imaging is unbelievable, because we know that intravascular imaging can improve outcomes in these patients,” he said. “If you have a restenosis or a stent thrombosis, it could be a disaster for someone with such an adverse risk factor profile [who has] only one patent coronary artery.”

“State-of-the-art PCI” should include intravascular imaging, Mamas stressed.

“We should not accept anything less than 100% perfection in the procedure outcome in this patient group,” he explained, “and you don’t have that unless you’ve adequately imaged the vessel so you can prepare it optimally and, at the end, image it to make sure that your stent’s adequately expanded, it’s apposed, and there’s no complications from your stent, such as edge dissection. You can’t do these things from an angiogram. We absolutely should be doing gold-standard PCI in these patients and if we can’t do gold standard PCI, refer to someone that can.”

Also, in the vast majority of cases, complete revascularization addressing the CTOs in the other epicardial arteries was not performed. Mamas said that could be because these patients were at such high risk, with operators not feeling comfortable doing CTO PCI in this group, which likely consists primarily of people turned down for surgery. Complete revascularization should be performed when possible,” he added. “I think we probably should, if there’s viability.”

And finally, Mamas said, it’s possible that greater use of MCS could improve outcomes in the setting of LRPV PCI. “Is there data to back that contention? No, not in this population,” he said. “But to my mind, it should be a consideration, particularly in those with impaired left ventricular function.”

Other tips for improving outcomes in the high-risk LRPV group, Mamas said, are teaming up with another experienced operator for the procedure and making sure all such cases are discussed with a multidisciplinary team that involves surgeons to select the best treatment approach.

Maran agreed with Mamas that interventional cardiologists should be pulling out all the stops for these very-high-risk cases, including much greater use of intravascular imaging.

“If you are going to work on the last remaining blood vessel, make sure you’re doing an extremely phenomenal job of it and use all the tools you have in your kit to help you,” she said. “Don’t sell yourself short, sell your work short. This is not the time . . . to do a shoddy job. Instead you want to perfect your job to ensure the clinical outcomes are going to be good.”