Conundrum of Classifying Subtypes of Pulmonary Hypertension—Introducing a Novel Approach to Classify “Borderline” Patients in a Population with Severe Aortic Stenosis Undergoing TAVI

Background: Transcatheter aortic valve implantation (TAVI) is an established therapeutic option in patients with severe aortic valve stenosis (AS) and a high surgical risk profile. Pulmonary hypertension (PH)—often co-existing with severe AS—is associated with a limited factor for prognosis and survival. The purpose of this study was to evaluate the prevalence of PH in patients undergoing TAVI, classify these patients based on right heart catheter (RHC) measurements in different PH subtypes, and analyze prognostic values on survival after TAVI. Methods: 284 patients with severe AS underwent an RHC examination for hemodynamic assessment prior to TAVI and were categorized into subtypes of PH according to the 2015 European Society of Cardiology (ESC) guidelines. TAVI patients were followed-up with for one year with regard to 30-days and 1-year mortality as primary endpoints. Results: 74 of 284 participants showed a diastolic pressure gradient (DPG) < 7 mmHg and a pulmonary vascular resistance (PVR) > 3 Wood units (WU) and could not be formally allocated to either isolated post-capillary PH (ipc-PH) or combined pre- and post-capillary PH (cpc-PH). Therefore, a new subgroup called “borderline post-capillary PH” (borderlinepc-PH) was introduced. Compared with TAVI patients with pre-capillary PH (prec-PH), ipc-PH patients suffering from borderlinepc-PH (HR 7.114; 95% CI 2.015−25.119; p = 0.002) or cpc-PH (HR 56.459; 95% CI 7.738−411.924; p < 0.001) showed a significantly increased 1-year mortality. Conclusions: Postcapillary PH was expanded to include the so-called “borderlinepc-PH” variant in addition to the ipc-PH and cpc-PH subtypes. The one-year survival after TAVI was significantly different between the subgroups, with the worst prognosis for borderlinepc-PH and cpc-PH.