Clinical Need: CAD CTO
Chronic total occlusions (CTOs) remain one of the greatest challenges facing interventional cardiologists and represent 10-15% of all percutaneous coronary intervention (PCI) procedures performed. As a result of CTOs, procedures are lengthier, more complicated and involve additional exposure to radiation.
A chronic total occlusion (CTO) is defined as the complete obstruction of a coronary artery, exhibiting thrombolysis in myocardial infarction (TIMI) 0 or TIMI 1 flow, with an occlusion duration of >3 months. The thrombosed segments become densely organized with fibrous tissue and calcify over time which makes them difficult to cross and treat. Sometimes, endothelialised micro-channels may cross through the occlusion and increase the chances of successful guidewire passage.
The primary reason for performing PCI to a CTO is to relieve angina. It is also performed in order to improve left ventricular function, reduce the risk of arrhythmias and the need for CABG surgery, and to prolong survival.
Figure 1: The 4 hybrid strategies applied in CTO-PCI
Several techniques are used for coronary CTO recanalization - the antegrade approach (green arrow), occlusion bypass within sub-intima space (blue arrow) or retrograde (black wires). When a procedure becomes more complex, operators use a hybrid approach that involves a combination of these techniques.
Most procedures preferably begin with an antegrade approach and shift to dissection or retrograde as the procedure becomes more complex. As the complexity increases, greater operator skill and experience is required to successfully cross the lesion.
STAGES OF LEARNING CTO PCI
Intraluminal revascularization with guidewire and support microcatheter
The access of choice. Pushing the guidewire’s tip through the proximal cap is frequently ineffective.
Antegrade dissection/subintimal approaches
Require more skills, more procedure time, and are more expensive.
Retrograde approach with
More costly, time-consuming, and requires advanced skill.
Increased complexity, time and cost
Nitiloop's devices, were invented by a cardiologist for cardiologists, and improve the antegrade re-canalization success rates while minimizing adverse events and improving overall procedure safety.