Research connected to Cavis Wirecath pressure guide wire
Clinical studies involving Wirecath are ongoing, e.g.
Sahlgrenska, Gothenburg, Sweden Clinicaltrials#NCT04776577
Catharina, Eindhoven, The Netherlands Clinicaltrials#NCT04802681
Clinical importance of simple and accurate CFR measurements
Existing invasive tools for measuring CFR and RRR have a number of disadvantages preventing their integration into standard care. The thermodilution technique has weak test-retest reliability as manual injections cause data variability (3). The Doppler technique is highly dependent on the skill/experience of the operator and there is insufficient quality of Doppler traces in up to 30% of measurements (4).
RRR is easily derived by pressure from CFR by the formula RRR = Pa rest/Pa hyp x CFR (2).
Pressure-derived CFR with
In-vitro study: Accuracy in pressure-derived CFR vs. thermodilution-CFR
Wirecath has been assessed regarding possible use for pressure-derived CFR. In a wetlab with pulsatile flow, we compared the accuracy of pressure-derived CFR using Wirecath with thermodilution-CFR using a commercially available pressure wire. CFR was overestimated by both methods to a similar extent in this in-vitro model.
Result: Pressure-derived CFR had better correlation with true CFR compared to thermodilution.
In-vitro study: Effects of focal vs. diffuse disease on accuracy in pressure-derived CFR
In the wetlab, we assessed the effects of focal versus diffuse disease on the accuracy of pressure-derived CFR.
Result: Accuracy was only slightly affected by the two simulated types of disease, diffuse and focal. When merging diffuse and focal data, there was a good correlation with true CFR.
Constriction with a negative angle edge and an inner diameter of 1.7 mm
300 mm tube with an inner diameter of 3.2 mm
Coronary Flow Reserve (CFR) measurements
What to do when there are no obstructive lesions?
Approximately 40% of angiography patients have non-obstructive coronary artery disease (1).
Rarely receive a definitive diagnosis
Are frequently labelled and managed inappropriately
Often continue to remain symptomatic
In-vitro study: Effects of hydrostatic error on accuracy in pressure-derived CFR
To simulate Pd-values with hydrostatic errors, the conservative average hydrostatic error of 1.0 mmHg (range -2 mmHg to +1 mmHg) was added randomly to Pd.
Result: The correlation between pressure-derived CFR and true CFR was abolished.
Clinical research in pressure-derived CFR with Wirecath is ongoing.