Optowire (Opsens Medical, distributed in the UK by OscarTech UK Ltd) is a sterile, fibreoptic-based, disposable guide wire for measuring fractional flow reserve (FFR) during coronary angiography in coronary artery diseases.
The device comprises a proprietary optical pressure sensor near to the tip, which minimises temperature and moisture-related drift, and a stainless-steel outer tube with a nitinol core for enhanced handling. The device needs a monitor, Optomonitor, and hardware to function. The company claims that Optowire's fibreoptic connector can reconnect to and disconnect from the measurement system during the procedure without interference from fluids. To measure FFR, the pressure wire is put through a guiding catheter to the lesion in the coronary artery. It records the pressure before and after a stenosis (narrowing) of an artery. The company has told NICE that the device can also measure diastolic pressure ratio (dPR). The most recent version of the device is the Optowire Deux.
FFR is a physiological parameter that measures the severity and significance of stenosis of an artery during coronary angiography. FFR is based on the maximum blood flow within the artery and is measured as the ratio between maximum achievable blood flow in a blocked artery and the theoretical maximum flow in a normal coronary artery. FFR can inform decisions about the appropriateness of stenting to unblock arterial stenosis.
Pressure drift can happen during FFR measurement. Pressure drift is a source of error in intracoronary pressure measurements and can result in a misclassification of stenosis. Pressure drift may be caused by the sensor, catheters and wires.
Coronary artery disease happens when arteries of the heart narrow because of deposits of atherosclerotic plaque. This narrowing can cause full or partial blockage of the coronary artery, leading to reduced blood flow and oxygen supply to the heart muscles. Coronary artery stenosis can lead to angina (chest pain), myocardial infarction (heart attack) and congestive heart failure.
Coronary artery disease is managed by lifestyle changes (for example, stopping smoking, regular exercise and diet) and medicines (such as antiplatelets, statins and beta-blockers). If lifestyle changes and medicines do not manage symptoms, interventional procedures and surgery can open or bypass blocked arteries.
Coronary angiography assesses if arteries are blocked and works out suitability for procedures such as percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG). It involves injecting a contrast agent and using X‑ray imaging to see the narrowing of the coronary artery. FFR is easily measured during routine coronary angiography by using a pressure wire. It is an add‑on test for PCI.
NICE's guideline on managing stable angina recommends coronary angiography to guide treatment strategy in people whose angina symptoms are not controlled by drug therapy. NICE's guideline on unstable angina or non-ST-segment-elevation myocardial infarction (NSTEMI) recommends drug therapy once the condition has been diagnosed. Coronary angiography is recommended within 96 hours of first admission for patients who have an intermediate or higher risk of adverse cardiovascular events.
Coronary angiography is also recommended with follow on primary PCI if needed. This is for people with acute ST‑elevation myocardial infarction (STEMI; see the NICE guideline on myocardial infarction with ST-segment elevation) if they present with symptoms within 12 hours of onset of symptoms and if PCI can be given within 120 minutes of when fibrinolysis could have been given. NICE medical technologies guidance on HeartFlow FFRCT for estimating FFR from coronary CT angiography recommends the non-invasive HeartFlow FFRCT for patients with stable, recent onset chest pain who are offered coronary CT angiography. This is part of the NICE Pathway on chest pain.
Optowire is for people with coronary artery disease, to measure FFR in interventional cardiology pressure wire procedures.
The device would be used by interventional cardiologists in a cardiac catheterisation laboratory setting, during PCI or diagnostic angiography.
A single Optowire device is £475 (excluding VAT) and the hardware costs £3,000 (excluding VAT). The cost per unit is lower depending on the length of the contract and the number of units purchased. Optowire can only be used with Optomonitor. Optomonitor has a 12‑month manufacturer warranty and the service and all updates are included in the cost of the technology.
The cost of comparator guide wires ranges between £25 and £900. Based on the National Tariff, the best practice tariff for ST‑segment elevation (actual or suspected myocardial infarction), ranges from £1,484 to £5,029 for the non-elective procedure. The best practice tariff for complex percutaneous or standard transluminal coronary angioplasty ranges from £2,617 to £7,889.
According to the company, the device has been used in the diagnosis and treatment of over 60,000 patients in more than 30 countries.
The resource impact would be greater than standard of care because of the device cost. This could be offset if the technology prevents misclassification of stenosis and avoids unnecessary stenting of an artery more than similar guide wires or non-invasive devices already in use.
There is minimal additional training required for insertion of Optowire for clinicians familiar with standard pressure wire guides. This training is included in the cost and provided at no charge.