Discongruence Index: predictor of prosthesis size loss after transcatheter aortic valve replacement

Introduction

Prosthesis under-expansion has been associated with higher rates of complications and worse long term outcome after transcatheter aortic valve replacement (TAVR). The objective of the current study was to assess the value of a new “Discongruence index”, to predict the percentage of prosthesis size loss (compared to its nominal size). The “discongruence index” is obtained from the relation between transcatheter valve size and the patient body surface area.

Methods

A total of 247 consecutive patients with severe aortic stenosis that underwent TAVR with balloon expandable Edwards-Sapiens prosthesis or CoreValve Revalving system at our institution were included. The “Discongruence index” was calculated pre-procedurally as the ratio: selected transcatheter valve size (mm) / body surface area (cm2). Two-dimensional transesophageal echocardiography images were studied in the 120–135° plane after the prosthesis deployment, and the maximum anteroposterior diameter was measured (in millimeters). From this measurement was obtained the percentage of prosthesis size loss (compared to the prosthesis nominal size).

Results

Mean age was 82±6 years and 102 patients (41.3%) were men. Mean aortic valvular area before TAVR was 0,87±3,8 cm2, (indexed 0,36±0,1 cm2) and the mean aortic gradient 49,1±16,9 mmHg. Mean prosthesis maximum deployment was 18,9±2,7 mm; absolute loss of prosthesis size compared to nominal 6,5±2,8 mm and the percentage loss of prosthesis size 25.1±9,5%. The “Discongruence index” was predictor of the percentage of prosthesis size loss (y = 5,7650 + 1,3010x, p<0,001), see figure.

Conclusions

The “Discongruence index” is a useful tool to predict the percentage of prosthesis size loss after TAVR. This new index should be taken into consideration in the selection of transcatheter valve sizes to avoid prosthesis under-expansion.

Funding Acknowledgement

Type of funding sources: None. Figure 1

Late results of bioabsorbable scaffolds implanted in spontaneous coronary artery dissection evaluated with computed tomography coronary angiography

Background

Percutaneous coronary intervention (PCI) in spontaneous coronary artery dissection (SCAD) should be reserved for cases presenting with ongoing extensive ischaemia. Bioresorbable scaffolds (BVS) have emerged as an alternative to avoid permanent stenting, an especially attractive concept for this clinical scenario. However, data of late angiographic outcome of this device in SCAD is lacking.

Purpose

To evaluate the long-term angiographic outcome of BVS in the setting of SCAD using computed tomography coronary angiography (CTCA)

Methods

In this multicentre prospective study, high-risk SCAD patients treated with BVS were scheduled for a follow-up CTCA at least 2 years from implantation date. Acquisition was performed according to the current recommendations. All the studies were analysed in a central core laboratory by an independent level 3 expert in CTCA blinded to the clinical and angiographic results. For this purpose, a dedicated software for coronary analysis was used to quantify coronary stenosis and evaluate coronary wall.

Results

Thirty-four BVS were implanted in 15 SCAD patients (51±12 years-old; 87% female) from 7 different centres in Spain and United Kingdom. The most common presentation was STEMI (n=9, 60%). Target vessels included 11 left anterior descending arteries (73.3%), 3 right coronary arteries (20%) and 1 left circumflex coronary artery (6.7%). One patient received target lesion revascularisation due to scaffold shrinkage in a proximal right coronary artery at 13 months. CTCA was performed 2.4±0.7 years after BVS implantation. No scaffold thrombosis or significant stenosis were detected. Patency of all scaffolds was confirmed with a median luminal area of 5.52 mm2 (IQR: 3.74–6.95) and median stenosis of 11% (IQR: 4–15%). Regarding coronary wall tissue characterization of segments with BVS, there was 32±9.3% of plaque burden and a median plaque volume of 45.3 mm3 (IQR: 26.6–61.9). The most common component of the plaque was fibrous (85±9.4%). Compared to the proximal reference segments, BVS showed more plaque burden (32.2% vs 25.3%; p=0.017) and fibrous percentage (84.7% vs 75.1%; p=0.004) whereas less fibrofatty (6 vs 4.8 mm3; p=0.007) and necrotic volume (0.4 vs 1.2 mm3; p=0.029). BVS segments showed lower absolute minimal luminal area (5.5 vs 8.9 mm2; p=0.004) and diameter (2.7 vs 3.4 mm; p=0.004) compared to the reference segment; however, non-significant differences were seen in percentage stenosis, in keeping with normal vessel tapering.

Conclusions

In this series of SCAD treated with BVS, scaffolds showed a satisfactory late angiographic outcome, with no significant restenosis and an excellent minimal luminal area and optimal coronary wall healing observed.

Funding Acknowledgement

Type of funding source: None