Annular Rupture During TAVR: Despite It, Dr. Alain Cribier Should Receive a Nobel Prize^∗ Free Access

Introduction

The aim of transcatheter aortic valve replacement (TAVR) is to mechanically help patients without undergoing an open-chest operation. Although the most important advantage over surgical aortic valve replacement might be psychological, there are some physical benefits. Therefore, it is logical that indication for TAVR has been changing from its historical form (being reserved only for high-risk patients who were not surgical candidates) toward low-risk patients (1,2). The new trend, which is a paradigm shift, is that surgery will be indicated for patients who are not TAVR candidates (3), such as cases with quite extensive calcification of the left ventricular outflow tract (LVOT).

Importantly, however, TAVR possesses some disadvantages when compared with conventional aortic valve surgery. The main problem of TAVR remains the uncertainty about the definitive result at the end of the procedure. Although it has improved with preprocedural imaging studies, it is still not possible to fully predict whether a patient undergoing TAVR will have relevant paravalvular leakage (with known negative consequences for late survival and a reason for preferring conventional aortic valve surgery in some cases) (4). The nightmare of the TAVR procedure is annular rupture. It can be difficult to treat or be untreatable. In contrast to the TAVR procedure, an experienced cardiac surgeon can successfully manage all mechanical intraoperative complications during conventional aortic valve surgery. Therefore, better understanding of the procedure-related problems with TAVR will further improve the results.

Annular rupture is a broad term covering different injuries that may occur in the region of the aortic root and the outflow tract, in the region of the so-called “device landing zone” (5–7), during TAVR. According to the anatomic location of the injury, there are 4 main types: supra-annular, intra-annular, subannular, and combined rupture (5). Annular rupture is a rare, unpredictable, and potentially fatal complication. It can be treated successfully if it is immediately recognized and adequately managed. The type of therapy depends on the location of the rupture and the clinical manifestations. Treatment approaches include an additional interventional procedure, conventional cardiac surgical procedure, isolated pericardial drainage, and conservative therapy (5–7).

In this issue of JACC: Cardiovascular Interventions, investigators from the University Hospital Bern, Switzerland (8), have provided strong data to support the use of TAVR as a primary strategy even among “high-risk” patients with severe calcification in the device landing zone (8). The current study is a large, single-institutional experience with 1,635 TAVR procedures using different TAVR devices. The investigators systematically reviewed the relationship between the preoperative computed tomography (CT) findings and their clinical outcome results. In particular, the amount of calcification in the LVOT and possible complications such as LVOT rupture and post-implantation valve insufficiency were analyzed. The study results confirmed that a small, but certain, number of patients would have a potentially detrimental procedural complication (e.g., annular rupture) that is difficult to manage. The study is retrospective, but the data used were from their prospective institutional registry.

The present study is based on a robust dataset of systematically assessed CT of TAVR patients. The authors precisely analyzed calcifications in the LVOT seen on CTs and summarized it in a semiquantitative way as mild, moderate, and severe. The 3 groups of patients were matched, and the results of the study demonstrate that the more calcification in LVOT as seen on CT, the more TAVR complications. On the first glance, these findings seem logical and not new. However, the clinical results from the Bern group are excellent—better than one would expect—despite a higher number of patients with LVOT calcifications. The study (8) nicely shows that TAVR procedures were safe in this particularly high-risk cohort, with only slightly increased 30-day mortality of 3.4%. This study emphasizes the importance of the combined work of surgeons and cardiologists as a team. Moreover, although involving 1,635 TAVR patients, the investigators only had 10 patients with LVOT rupture. This low occurrence (0.6%) is impressive. Annular rupture occurred more frequently in patients with moderate/severe LVOT calcification than in patients with none or mild LVOT calcification with incidences of 2.3% and 0.2%, respectively (8). By contrast, given the low number of events, the findings warrant cautious interpretation of the statistical analyses.

It should be also mentioned that the result of the analysis of post-implantation valve insufficiency – the second main point of interest of the study - is of less relevance because post-implantation valve insufficiency is multifactorial in etiology. Paravalvular leak is dependent, not only on the amount of calcium in the LVOT, but is also influenced by the implantation strategy (9). The additional important message of the present paper is that there is no 1 strategy for all patients (8). Patients with LVOT calcifications require special consideration in pre-procedural planning of the TAVR procedure. The heart team should pre-operatively develop an individual strategy for each patient answering the question: “How should we modify the TAVR procedure in patients with increased calcification in the LVOT in order to prevent possible complications?”

TAVR needs future technical developments in order to eliminate its drawbacks, such as annular rupture and paravalvular insufficiency. From a surgical point of view, a logical step should be development of a procedure and adequate equipment to excise the native aortic valve tissue. This would enable precise implantation of a TAVR prosthesis in a “clean” region. Additionally, the effect on cognitive function of cerebral microembolization and the ischemic microlesions that always occur during all phases of valve implantation (10) remains to be optimally addressed. These factors should be considered critically before the procedural indication is broadened to yet younger and lower-risk patients (4).

The education and training of prospective cardiologists and surgeons should be adapted to demands of TAVR (4). Ideally, a TAVR team should be able to perform all types of TAVR procedures and conventional aortic valve surgery, and to treat its own procedural complications using catheter-based or surgical methods. Thus, the same team should be able to perform that procedure assessed to be the best for each patient. In the future, cardiovascular training should include the knowledge, skills, and experience of both a cardiologist and a conventional cardiovascular surgeon. Complications will be managed mostly using a catheter-based technique, with surgical revision needed only if the interventional method is not possible or fails to treat the complication (4).

TAVR is a revolutionary step in medicine, a real breakthrough. I believe that the persons who contributed to the experimental development and clinical introduction of TAVR, such as Drs. Davis (11), Anderson (12), and Cribier (13) deserve the Nobel prize for their pioneering work.

Footnotes