LUS in Aortic Stenosis Patients Undergoing TAVR

1. Introduction and aims:

Transcatheter aortic valve replacement (TAVR) is the gold standard for the treatment of elderly patients with severe aortic valve stenosis (AS). AS causes left ventricular remodeling as well as left atrial enlargement, pulmonary artery and right ventricular changes, these changes, and whether they are reversible (reverse remodeling) are major determinants of outcome after TAVR. Heart Failure (HF) is the most frequent cause of cardiac re-hospitalization after TAVR. Most HF exacerbations are related to a progressive rise in cardiac filling pressures that precipitates pulmonary congestion and symptomatic decompensation. Traditionally, pulmonary congestion has been assessed by physical examination and chest radiography but clinical signs and symptoms of congestion are poor surrogates for ventricular filling pressures and are not reliable predictors of imminent hospitalization. Recently, lung ultrasonography (LUS) has been identified as a sensitive and semi-quantitative tool for the assessment of pulmonary congestion in HF. The technique is based on the detection of vertical echogenic artifacts arising from the pleural line, named "B-lines". The number of B-lines is associated with increased risk of adverse events during hospitalization and after hospital discharge. CLUSTER-HF Trial demonstrated that the routine incorporation of LUS during clinical follow-up of patients with recent acute decompensated HF without a surgically correctable cause, was associated with a risk reduction of adverse HF events, mainly urgent HF visits.

Thus, LUS could represent a promising tool to detect pulmonary congestion related to AS. To date, there are no studies on the role of LUS in the context of AS and TAVR.

The study hypothesis is that in patients with higher number of B-lines before-TAVR and after TAVR, the rate of adverse events during follow-up is higher.

2. Study design:

This is a single center prospective study carried out at Fondazione Policlinico Gemelli IRCCS, Roma and involving patients with severe aortic stenosis submitted to TAVR treatment. The expected recruitment period is approximately one year For patients fulfilling inclusion/exclusion criteria, all data about clinical status leading to TAVR, exams and any specific documentation during hospitalization will be collected.

3. Number of patients:

For the primary end-point, a sample-size of 91 is computed using the one-sample chi-square test and assuming a proportion of LUS-evaluated pulmonary congested patients before TAVR of 50% and a proportion of 35% of LUS-evaluated pulmonary congested patients after TAVR. To accommodate for possible missing investigations, sample size will be increased to 105 patients.

The secondary end-point is the association between pre-TAVR and post-TAVR B-lines and long-term outcomes. Based on previous studies, the investigators know that the incidence of rehospitalization for heart failure during one-year after TAVR is 14% and that patients suffering from heart failure without LUS-evaluated pulmonary congestion are at very low risk of heart failure rehospitalization during follow-up. So, for sample size calculation of the secondary endpoint, the investigators estimated a cumulative incidence higher in the LUS- evaluated pulmonary congestion group with more than 16 B-lines on all scanning sites (30% of events during 1-year of follow-up) with a lower incidence of 8% in the remaining patients. With an HR of 5 favoring patients wit less than 15 B-Lines on all scanning, and aiming to a 2-sided alpha level of 0.05 and a power of 80% the investigators estimated 144 patients. To accommodate for possible missing investigations, sample size will be increased to 150 patients.

4. In-hospital study schedule:

For each patient, the investigators will obtain from our general hospital database the following clinical data:

• Demographic and clinical data documentation;
• Clinical examination: before TAVR, before discharge and when adverse events occur;
• Blood analysis;
• TAVR procedural characteristics and complications. 5. Instrumental diagnostic exams (Echocardiography and lung ultrasound):

Each patient will be evaluated before and after TAVR with a comprehensive echocardiogram and LUS for the evaluation of the pulmonary congestion. All the evaluations will be performed the day before TAVR and after TAVR.

In consideration of the operator's dependence on ultrasound methods to reduce the error rate, all examinations will be performed by qualified personnel.

6. Clinical follow up assessment:

Clinical follow up information will be obtained from: visits, review of the patient's hospital record, personal communication with the patient's physician and review of the patient's chart, a telephone interview with the patient conducted by trained medical personnel The following information will be recorded: clinical status assessment, adverse event assessment, record cardiac medications.