Previous CABG Limits Success of CTO PCI in Native Coronary Arteries

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Stenting of chronic total occlusions (CTOs) is less likely to be successful in patients who have previously undergone coronary artery bypass graft (CABG) surgery compared to those with no history of CABG, according to a study published online January 21, 2014, ahead of print in JACC: Cardiovascular Interventions

Tomohiko Teramoto, MD, PhD, of the Toyohashi Heart Center (Aichi, Japan), and colleagues conducted a prospective database analysis of CTO-PCI procedures conducted between May 1999 and November 2011. Investigators identified 153 patients with (n = 206 cases) and without (n = 1139 patients; 1431 cases) prior CABG in their native coronary arteries.

CABG, Non-CABG Cases Diverge

The initial success rate of CTO-PCI procedures, defined as residual stenosis less than 50% with TIMI low grade 3 in the absence of MACE, was lower in previous CABG patients (71%) than in those who had yet to undergo surgery (83%; P < 0.0001).

Baseline characteristics and procedural factors differed according to whether patients had prior CABG.

Both severe calcification and LCX lesion location were more common in the CABG group. While the frequency and success of antegrade guidewire approaches were similar between the 2 groups, the use of retrograde attempts, including controlled antegrade and retrograde subintimal tracking (CART), was more common in prior CABG cases than in non-CABG (47% vs 37%; P = 0.001). The success rate of CART in particular, which was used in 22% of CABG cases and 11% of non-CABG cases, was lower in the previous CABG group (71% vs 89%; P = 0.004).

Procedural disadvantages included longer CTO-PCI and fluoroscopy time and greater radiation exposure, all of which were higher in the previous CABG group. Type A coronary perforation was also more common. (table 1).

Table 1. Procedural Factors

 

CABG
(n = 206 cases)

Non-CABG
(n = 1431 cases) 

P value

   Procedure time, min

210.3 ± 98.1

165 ± 77.3

< 0.0001

   Fluoroscopy time, min

64.2 ± 44.1

51.2 ± 34.0

0.0002

   Frontal radiation exposure, Gy

6.2 ± 5.9

4.8 ± 4.0

0.0019

   Lateral radiation exposure, Gy

5.9 ± 10.6

4.3 ± 3.3

0.0017

   Type A coronary perforation

15.5%

14.4%

0.02


In-hospital rates of death, Q-wave MI and urgent CABG were similar between the 2 groups.

The time since CABG was longer in individuals with failed CTO-PCI than in those who underwent successful procedures (3831 ± 2139 days vs 3068 ± 2445 days; P = 0.03).

On logistic regression analysis, independent predictors of greater CTO-PCI success in a native coronary artery of previous CABG patients included use of IVUS (OR 3.74; 95% CI 1.31-10.67; P = 0.01) and parallel wiring (OR 3.29; 95% CI 1.79- 6.04; P = 0.0001). Lesion tortuosity was determined to be an independent predictor of lower success (OR 0.24; 95% CI 0.13- 0.49; P < 0.0001).

“Factors concomitant with the CTO-PCI procedure, such as complexity of anatomy, hemodynamic instability leading to ischemia, and exposure to radiation, are all recognized factors that could be problematic for the interventional cardiologist,” write the study authors.

Study Confirms Prior Research

In an e-mail communication with TCTMD, Dr. Teramoto wrote that although prior CABG is a well-known hindrance for CTO-PCI success, clinical outcomes associated with CTO-PCI in a native coronary artery in prior CABG patients have not been thoroughly investigated. Overall, the procedure is relatively uncommon in this population, he said, adding that 11.8% of prior CABG patients in the entire database received CTO-PCI.

Emmanouil S. Brilakis, MD, PhD, of VA North Texas Health Care System (Dallas, TX), commented in an e-mail communication with TCTMD that while the current study evaluates a relatively small proportion of prior CABG patients and Japan lacks antegrade dissection/re-entry equipment, the paper confirms his own research.

Numerous Challenges to Prior CABG

The challenges associated with treating patients with previous CABG is due to the anatomical complexity,” said Dr. Teramoto. The trajectory of the native coronary artery is difficult to anticipate, he noted. Moreover, because of the long duration of occlusion, it may be too calcified to allow guidewire passing.

Another obstacle to contend with, added Dr. Brilakis, is that the bypass anastomosis in these patients may distort the anatomy, causing tenting of the native vessel.

According to Dr. Teramoto, retrograde procedures using the CART technique in previous CABG patients may have been associated with lower success rates because of anatomical complexity of the native coronary artery after CABG.

Moreover, a bypass graft is often the last effective vessel in these individuals, and treating an occluded native coronary artery via bypass grafts often provokes much broader ischemia, inducing an unstable hemodynamic state. “Once hemodynamic instability occurs, it is hard to pursue the PCI procedure, and any complications involving bypass graft should be avoided,” he said. 

Ensuring Good Outcomes

An antegrade approach should be reconsidered for a CTO-PCI procedure after CABG to help improve patient safety, advised Dr. Teramoto. A novel technique taking advantage of the antegrade approach might be crucial in achieving better initial results of CTO-PCI in this patient population, he said.

Expertise with all available techniques, including antegrade wiring, antegrade dissection/ re-entry, and retrograde strategies, is needed to ensure successful outcomes for this subgroup, said Dr. Brilakis. He noted that meticulous attention should also be paid to radiation exposure that can accompany prolonged CTO crossing attempts.

 


Source:
Teramoto T, Tsuchikane E, Matsuo H, et al. Initial success rate of percutaneous coronary intervention for chronic total occlusion in a native coronary artery is decreased in patients who underwent previous coronary artery bypass graft surgery. J Am Coll Cardiol Intv. 2014;Epub ahead of print.

 

 

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Previous CABG Limits Success of CTO PCI in Native Coronary Arteries

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Disclosures
  • Dr. Teramoto reports no relevant conflicts of interest.
  • Dr. Brilakis reports receiving speaker honoraria from Abbott Vascular, Asahi, Boston Scientific, Janssen, Sanofi, St Jude Medical, and Terumo and research support from Guerbet. His spouse is an employee of Medtronic.

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