Coronary obstruction (CO) following transcatheter aortic valve replacement (TAVR) is a rare, but often fatal, complication, say researchers, who identify a lack of predisposing factors and challenges in treating the blockage as possible explanations.
Writing in the May 22 issue of JACC Cardiovascular Interventions, researchers overseeing the largest registry analyzing CO after TAVR demonstrate that the incidence of this complication has not decreased over the years.
“In a real-world setting, previously proposed risk factors for CO were not frequent in a subset of patients, especially in those undergoing native valve procedures,” said the team, led by Soledad Ojeda, MD, PhD, and Rafael González-Manzanares, MD, PhD, from Hospital Universitario Reina Sofía and Instituto Maimónides de Investigación Biomédica de Córdoba, Spain.
“Thus, further research is needed in order to improve the prediction and identification of patients at risk of CO,” they added.
Transcatheter Aortic Valve Implantation registry
The research team analyzed the incidence of CO after TAVR, presentation, management, and in-hospital and 1-year clinical outcomes in a large series of patients undergoing TAVR.
The present study included 13,675 patients from the Spanish TAVI (Transcatheter Aortic Valve Implantation) registry, 115 of whom presented with CO.
Computed tomography (CT) risk factors were also assessed, with in-hospital, 30-day and 1-year all-cause mortality rates analyzed and compared with patients without CO.
The research team used logistic regression models in the overall cohort and in a propensity score-matched cohort.
Findings of the study, which were also published Monday online, revealed that out of the patient population, 115 (0.80%) presented with a CO, mainly during the procedure (83.5%). This population had a median age of 83 years (range 80-86 years) and 65.2% were female.
A majority of patients presenting with CO, 96 (83.5%), did so periprocedurally, while 12 (10.4%) presented during postprocedure hospitalization and the remaining seven presented at follow-up.
Further findings revealed the incidence of CO was stable throughout the study period (2009-2021), with a median annual rate of 0.8% (range 0.3% to 1.3%).
Preimplantation CT scans were available in 105 patients (91.3%). The combination of at least two CT-based risk factors was less frequent in native-valve than in valve-in-valve patients (31.7% vs 78.3%; P < 0.01).
Further results revealed that percutaneous coronary intervention (PCI) was the treatment of choice in 100 patients (86.9%), with a technical success rate of 78.0%.
Meanwhile, mortality rates were higher in CO patients than in those without CO, with the in-hospital rate calculated at 37.4% vs 4.1% (P=0.001); 30-day, 38.3% vs 4.3% (P<0.001); and 1-year, 39.1% vs 9.1% (P<0.001).
“It is important to highlight that the incidence of delayed CO might have been underestimated due to several reasons,” said the researchers. “First, conservative management of acute coronary syndrome is not rare in this population owing to patient and procedural-related factors which could have led to an underdiagnosis of this condition.”
Prior coronary artery bypass graft
The Spanish-based team went on to state that patients who underwent a prior coronary artery bypass graft may be relatively protected as well as the possibility that if out-of-hospital cardiac arrest was the clinical presentation, the diagnosis would be missed.
Commenting on the predisposing factors of CO, the team acknowledged that its prediction was not precise, especially in native aortic valve procedures.
“In fact, only one-third of the patients in this registry had a combination of at least 2 of the classical CT factors of CO,” they wrote, “and despite experience, the incidence of this complication did not significantly decrease throughout the years, being similar to that previously reported. Therefore, it is of paramount importance to improve CO risk prediction.”
CO’s low incidence and multifactorial causality
In an accompanying editorial comment, Ariel Finkelstein, MD, and Jeremy Ben-Shoshan, MD, PhD, from Tel Aviv University in Israel, highlight that the lack of a temporal decrease in the frequency of CO implies the need for better understanding and preventive tools.
They cite a study, in which the team evaluated the preprocedural CT studies of a large dataset of patients who underwent TAVR in native aortic valves with (n=60) and without (n= 1,381) CO.
“On the basis of the gathered data, the investigators established a relatively simple algorithm for the prediction of direct coronary obstruction in a native aortic valve, defined as cusp height (vertical distance from the annular plane to the top of the cusp commissural attachment) greater than coronary artery height and a VTC distance <4 mm or culprit leaflet calcium volume > 600 mm3,” the editorialists wrote. “The model performance was validated successfully using propensity score matching for age, sex, and annular area (area under the curve ~0.93). Established randomized data regarding reliable predictors of coronary obstruction are still missing because of its low incidence and multifactorial causality.” Given the lack of randomized-trial data, Finkelstein and Ben-Shoshan concluded, large-scale registry analyses such as the one reported by Ojeda, González-Manzanares and colleagues, “remain crucial” to help clinicians understand the incidence of CO after TAVR and how best to treat it.
Ojeda S, González-Manzanares R, Jiménez-Quevedo P, et al. Coronary Obstruction After Transcatheter Aortic Valve Replacement: Insights From the Spanish TAVI Registry. JACC Cardiovasc Interv. 2023;16: 1208–1217.
Finkelstein A, Ben-Shoshan J. Coronary Obstruction in TAVR: (Not) Knowing Your Enemy. JACC Cardiovasc Interv. 2023;16:1218–1220.
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