Pulmonary Vascular Reverse Remodeling After Left Ventricular Assist Device Implantation in Patients With Pulmonary Hypertension

Prevalence of combined pre- and post-capillary (Cpc) pulmonary hypertension (PH) in patients with PH due to left heart disease (PH-LHD) and the long-term impact of left ventricular assist device (LVAD) implantation in patients with Cpc-PH are not fully elucidated. Eighty-nine patients with PH-LHD who underwent LVAD implantation were retrospectively analyzed. Patients were divided into two groups according to their preoperative pulmonary vascular resistance (PVR) and diastolic pressure gradient (DPG) values (Cpc-PH group, PVR >3 wood units [WU], or DPG ≥7 mmHg; isolated postcapillary [Ipc]-PH group, PVR ≤3 WU, and DPG <7 mmHg). There were 50 patients with Cpc-PH (PVR >3 WU [group A, n = 41]; PVR >3 WU and DPG ≥7 mmHg [group B, n = 8]; DPG ≥7 mmHg [group C, n = 1]), and 39 patients with Ipc-PH. Despite a successful LVAD implantation in all participants, 13 and two patients remained in groups A and B, respectively, early after LVAD implantation, whereas two patients each remained in groups A and B 1 year postoperatively. Values of PVR and DPG in the Cpc-PH group returned to normal levels by 3 years postoperatively. Over 50% of patients with PH-LHD had Cpc-PH, and PVR and DPG normalized in all participants within 3 years after LVAD implantation.

Combined pre- and post-capillary pulmonary hypertension in left heart disease

Patients with heart failure (HF) often have pulmonary hypertension (PH), which is mainly post-capillary; however, some of them also develop a pre-capillary component. The exact mechanisms leading to combined pre- and post-capillary PH are not yet clear, but the phenomenon seems to start from a passive transmission of increased pressure from the left heart to the lungs, and then continues with the remodeling of both the alveolar and vascular components through different pathways. More importantly, it is not yet clear which patients are predisposed to develop the disease. These patients have some characteristics similar to those with idiopathic pulmonary arterial hypertension (e.g., young age and frequent incidence in female gender), but they share cardiovascular risk factors with patients with HF (e.g., obesity and diabetes), with both reduced and preserved ejection fraction. Thanks to echocardiography parameters and newly introduced scores, more tools are available to distinguish between idiopathic pulmonary arterial hypertension and combined PH and to guide patients' management. It may be hypothesized to treat patients in whom the pre-capillary component is predominant with specific therapies such as those for idiopathic pulmonary arterial hypertension; however, no adequately powered trials of PH-specific treatment are available in combined PH. Early evidence of clinical benefit has been proven in some trials on phosphodiesterase type 5 inhibitors, while data on prostacyclin analogues, endothelin-1 receptor antagonists, and soluble guanylate cyclase stimulators are still controversial.

An updated meta-analysis of hemodynamics markers of prognosis in patients with pulmonary hypertension due to left heart disease

Pulmonary hypertension (PH) is associated with a poor prognosis in left heart disease (LHD). We sought to provide an updated analysis on the association of hemodynamic variables, such as pulmonary vascular resistance (PVR), pulmonary artery compliance (PAC), and diastolic pressure gradient (DPG), with prognosis in PH-LHD, through a systematic literature review. Sixteen articles were identified, including 9600 patients with LHD, heterogeneous in terms of age, sex, and etiology of cardiac disease. In this large population, PVR (hazard ratio [HR], 1.07; 95% confidence interval [CI]: 1.05-1.0), DPG (HR, 1.02; 95% CI: 1.01-1.02) and PAC (HR, 0.76; 95% CI: 0.69-0.84) were associated with an increased risk of adverse outcome, albeit with a less solid performance of DPG. Similar results were found when hemodynamic variables were analyzed according to the thresholds commonly applied in clinical practice, or subdividing cohorts according to the underlying LHD. Furthermore, cumulative metanalysis indicated that these results are consistently stable since 2018. Thus, PVR, DPG and PAC have an established prognostic value in PH-LHD. These results are consistent through the years and unlikely to change with further studies.

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.

Animal models of pulmonary hypertension due to left heart disease

Pulmonary hypertension due to left heart disease (PH‐LHD) is regarded as the most prevalent form of pulmonary hypertension (PH). Indeed, PH is an independent risk factor and predicts adverse prognosis for patients with left heart disease (LHD). Clinically, there are no drugs or treatments that directly address PH‐LHD, and treatment of LHD alone will not also ameliorate PH. To target the underlying physiopathological alterations of PH‐LHD and to develop novel therapeutic approaches for this population, animal models that simulate the pathophysiology of PH‐LHD are required. There are several available models for PH‐LHD that have been successfully employed in rodents or large animals by artificially provoking an elevated pressure load on the left heart, which by transduction elicits an escalated pressure in pulmonary artery. In addition, metabolic derangement combined with aortic banding or vascular endothelial growth factor receptor antagonist is also currently applied to reproduce the phenotype of PH‐LHD. As of today, none of the animal models exactly recapitulates the condition of patients with PH‐LHD. Nevertheless, the selection of an appropriate animal model is essential in basic and translational studies of PH‐LHD. Therefore, this review will summarize the characteristics of each PH‐LHD animal model and discuss the advantages and limitations of the different models.

Wedge Pressure vs Left Ventricular End-Diastolic Pressure for Pulmonary Hypertension Classification and Prognostication in Severe Aortic Stenosis

BACKGROUND

Differentiation between precapillary and postcapillary pulmonary hypertension (PH) classically relies on mean pulmonary artery wedge pressure (mPAWP). The left ventricular end-diastolic pressure (LVEDP) is proposed as an equivalent alternative. However, mPAWP and LVEDP may differ substantially. We compared the impact of the choice of using the mPAWP vs the LVEDP on PH classification and mortality prediction in patients with severe aortic stenosis (AS) undergoing valve replacement.

METHODS

In 335 patients with severe AS , both mPAWP and LVEDP were measured. A mean pulmonary artery pressure ≥ 25 mm Hg was used to define PH, and either mPAWP or LVEDP was used to differentiate between precapillary and postcapillary PH (≤ 15 vs > 15 mm Hg). Mortality after a median follow-up of 1484 days after aortic valve replacement was assessed.

RESULTS

Overall, mPAWP was lower than LVEDP (16 ± 8 mm Hg vs 21 ± 8 mm Hg; P < 0.001). Among 140 patients (42%) with PH, the PAWP-based classification revealed 76 (54% of those with PH) with isolated postcapillary PH, 48 (34%) with combined pre- and postcapillary PH, and 16 (12%) with precapillary PH. When the LVEDP was used, 59 patients (42%) were differently classified. These patients had higher mortality than those who were not differently classified [hazard ratio 2.79 (95% confidence interval, 1.17-6.65); P = 0.02]. Higher mPAWP was associated with increased mortality [hazard ratio 1.07 (95% confidence interval, 1.03-1.11) per 1 mm Hg; P = 0.001], whereas higher LVEDP was not.

CONCLUSIONS

Use of LVEDP rather than mPAWP results in a divergent PH classification in nearly every second patient with severe AS. These patients have higher mortality after aortic valve replacement. The mPAWP, but not the LVEDP, predicts mortality.

Impact of the new pulmonary hypertension definition on long-term mortality in patients with severe aortic stenosis undergoing valve replacement

Background

The new 2018 pulmonary hypertension (PH) definition includes a lower mean pulmonary artery pressure (mPAP) cut‐off (>20 mmHg rather than ≥25 mmHg) and the compulsory requirement of a pulmonary vascular resistance (PVR) ≥3 Wood units (WU) to define precapillary PH. We assessed the clinical impact of the 2018 compared to the 2015 PH definition in aortic stenosis (AS) patients undergoing aortic valve replacement (AVR).

Methods

Severe AS patients (n = 487) undergoing pre‐AVR right heart catheterization were classified according to the 2015 and 2018 definitions. Post‐AVR mortality (median follow‐up 44 months) was assessed.

Results

Based on the 2015 definition, 66 (13%) patients exhibited combined pre and postcapillary PH (CpcPH), 116 (24%) isolated post‐capillary PH (IpcPH), 28 (6%) precapillary PH, and 277 (57%) no PH at all. Overall, 52 (11%) patients were reclassified: 23 no PH into IpcPH; 8 no PH into precapillary PH; 20 precapillary PH into no PH; 1 CpcPH into IpcPH. By the 2015 definition, only CpcPH patients displayed increased mortality, whereas by the 2018 definition, precapillary PH patients also experienced higher mortality than those without PH. Among the PH definition components, PVR ≥3 WU was the strongest predictor of death (hazard ratio > 4).

Conclusions

In severe AS, a higher number of IpcPH patients are diagnosed by the 2018 definition, even though they have the same prognosis as those without PH. Patients with true precapillary PH are more accurately identified by the 2018 definition that includes a pulmonary vascular disease criterion, that is, PVR ≥3 WU, a strong mortality predictor.