Comparison of transcatheter, minimally invasive and conventional surgical aortic valve replacement: a systematic review and network meta-analysis

Funding Acknowledgements

Type of funding sources: None.

Background/Introduction

The landscape of aortic valve replacement (AVR) has evolved dramatically over the years, but long-term outcomes have yet to be comprehensively explored.

Purpose

To compare long-term mortality among three AVR techniques: transcatheter (TAVI), minimally invasive (MIAVR), and conventional surgical AVR (CAVR).

Methods

An electronic literature search was performed for randomized controlled trials (RCTs) comparing TAVI to CAVR, and RCTs or propensity score-matched (PSM) studies comparing MIAVR to CAVR or MIAVR to TAVI. Individual patient data for all-cause mortality was derived from graphical reconstruction of digitized Kaplan-Meier curves. Pairwise comparisons followed by network meta-analysis were conducted. Sensitivity analyses were performed in the TAVI arm for high risk and low/intermediate risk as well as transfemoral (TF-TAVI) patients.

Results

A total of 27 studies involving 16,554 patients were included. In the pairwise comparison of TAVI versus CAVR, TAVI showed superior mortality to CAVR until 39.5 months, beyond which there was no significant difference in longer term mortality. When restricted to TF-TAVI versus CAVR, consistent mortality benefit favoring TAVI was seen (shared-frailty hazard ratio [HR]=1.17, 95%CI=1.03-1.33, p=0.016). In the network meta-analysis involving majority PSM data, MIAVR was associated with significantly lower mortality than TAVI (HR=0.69, 95%CI=0.59-0.82) and CAVR (HR=0.68, 95%CI=0.58-0.80); this significant association was not seen when compared to TF-TAVI patients.

Conclusions

An initial short-medium term mortality benefit for TAVI over CAVR was noted but this benefit was attenuated over the longer term. In the subset of TF-TAVI patients, this long-term mortality benefit persisted, suggesting that non-TF techniques are associated with higher mortality. Amongst majority PSM data, MIAVR showed improved mortality compared to TAVI and CAVR but this was not seen in the TF-TAVI subset. This suggests that MIAVR may have a role in treating patients who are ineligible for TF-TAVI in experienced centers, and future RCTs are needed to conclusively validate this.

Computed tomography and cystic fibrosis: promises and problems

Computed tomography (CT) has two potential roles in the evaluation of patients with cystic fibrosis (CF) lung disease: as a diagnostic test primarily for the detection of supervening complications and as a monitoring tool in clinical research. Interest in the latter role has gained momentum in the last 5 years because of two factors: (1) therapeutic options for CF lung disease are developing rapidly, hence the need for an outcome measure that can be applied in clinical intervention trials; and (2) it has become clear that traditional outcome measures such as pulmonary function tests are relatively insensitive to the early structural damage that occurs in CF. Several recent studies have shown that CT can be used as a potential surrogate outcome measure, although its suitability for this specific role is controversial and still under investigation. This review summarises current concepts relating to the research applications of CT in CF, with particular emphasis on the evidence supporting the use of CT as a surrogate outcome measure in clinical trials.

HRCT diagnosis of diffuse parenchymal lung disease: inter-observer variation

BACKGROUND

This study was designed to measure inter-observer variation between thoracic radiologists in the diagnosis of diffuse parenchymal lung disease (DPLD) using high resolution computed tomography (HRCT) and to identify areas of difficulty where expertise, in the form of national panels, would be of particular value.

METHODS

HRCT images of 131 patients with DPLD (from a tertiary referral hospital (n = 66) and regional teaching centres (n = 65)) were reviewed by 11 thoracic radiologists. Inter-observer variation for the first choice diagnosis was quantified using the unadjusted kappa coefficient of agreement. Observers stated differential diagnoses and assigned a percentage likelihood to each. A weighted kappa was calculated for the likelihood of each of the six most frequently diagnosed disease entities.

RESULTS

Observer agreement on the first choice diagnosis was moderate for the entire cohort (kappa = 0.48) and was higher for cases from regional centres (kappa = 0.60) than for cases from the tertiary referral centre (kappa = 0.34). 62% of cases from regional teaching centres were diagnosed with high confidence and good observer agreement (kappa = 0.77). Non-specific interstitial pneumonia (NSIP) was in the differential diagnosis in most disagreements (55%). Weighted kappa values quantifying the likelihood of specific diseases were moderate to good (mean 0.57, range 0.49-0.70).

CONCLUSION

There is good agreement between thoracic radiologists for the HRCT diagnosis of DPLD encountered in regional teaching centres. However, cases diagnosed with low confidence, particularly where NSIP is considered as a differential diagnosis, may benefit from the expertise of a reference panel.