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Hybrid algorithm for CTO linked to high procedural success, low event rates
The hybrid algorithm for chronic total occlusion PCI appears to yield high procedural and patient success rates, along with a low event rate and improved procedural characteristics, according to data from the RECHARGE registry.
In the study, researchers evaluated 1,177 consecutive patients (mean age, 66 years; 86% men) who underwent CTO PCI at 17 sites in Belgium, France and the Netherlands between January 2014 and October 2015. The hybrid algorithm was employed, leaving the choice of strategy at the discretion of the operators.
Based on the criteria of the algorithm, angiographic assessment of CTO lesion characteristics was performed preoperatively to determine optimal or consecutive strategies (antegrade wire escalation [AWE], antegrade dissection and re-entry [ADR], retrograde dissection and re-entry [RDR] or retrograde wire escalation [RWE]).
Although the operators had a range of experience in performing hybrid techniques, all had performed at least 25 hybrid procedures and were certified ADR operators, according to the researchers.
The primary endpoint was validation of the hybrid algorithm’s effectiveness and determination of the potential success rate in CTO lesions in terms of complexity based on Japanese CTO (J-CTO) score. Secondary endpoints included the outcomes of the individual techniques (AWE, ADR, RWE, RDR), procedural safety characteristics and determination of in-hospital MACCE.
Success for most
The researchers found that the procedures yielded an overall 86% success rate (1,075 of 1,253 procedures). Centers or operators with a case volume of more than 100 cases per year had a higher average success rate vs. lower-volume operators (91% vs. 82% vs. 83%; P < .001).
Patients in whom these procedures were unsuccessful had a higher rate of previous MI (48% vs. 38%; P = .011), previous CABG (35% vs. 15%; P < .001) and previous CABG on the CTO target vessel (25% vs. 11%; P < .001).
There was a 2.6% rate of in-hospital MACCE (n = 33). There were three deaths, one a sudden death overnight after the procedure, one due to aortic dissection 6 hours after the procedure that necessitated surgery, and one from shock after a staged non-target-vessel PCI during the same hospitalization. Additional MACCE included stroke (n = 3), acute MI (n = 27) and acute vessel closure necessitating immediate target vessel revascularization.
AWE was chosen as the primary strategy in 77% (n = 958) of cases, followed by retrograde technique in 17% (n = 207) and ADR in 7% (n = 88). Overall, there was a 60% rate of success for the primary strategy. AWE was successful in 62% of cases (n = 594), ADR was successful in 67% of cases (n = 59) and retrograde strategies were successful in 50% of cases (n = 104). In 34% of cases, consecutive strategies were employed, and 74% of these were successful.
The most prevalent bailout strategies were ADR and retrograde strategies. Sixty-seven percent of ADR bailout procedures were successful, and 62% of retrograde bailout procedures were successful. The median procedure time was 90 minutes (interquartile range [IQR], 60-120) and the median fluoroscopy time was 35 minutes (IQR, 21-55). Median contrast volume was 250 mL (IQR, 180-348) and median radiation doses were 1.6 Gy for air kerma (IQR, 1-2.7) and 98 Gy.cm2 (IQR, 57-168) for dose area product.
Experience matters
In a related editorial, David R. Holmes Jr., MD, of the department of cardiology, Mayo Clinic, and colleagues wrote these findings support the effectiveness of the hybrid algorithm, but they also emphasize the importance of operator and center experience.
“The RECHARGE registry demonstrated that high technical success rates can be accomplished using the hybrid approach to CTO PCI by operators with various experience levels,” Holmes, a member of the Cardiology Today Editorial Board, and colleagues wrote. “Still, operator experience mattered, with more experienced operators having higher success rates despite treating more complex occlusions.” – by Jennifer Byrne
Disclosure: Boston Scientific provided a research grant to the project. Holmes reports no relevant financial disclosures. Please see the full study and editorial for a list of the relevant financial disclosures of the researchers and other editorial authors.