Percutaneous coronary intervention (PCI) for chronic total occlusions (CTO) remains one of the most demanding challenges for an interventional cardiologist. Technological developments have improved efficacy and safety, but complications still occur and their incidence remains higher than that observed in non-CTO PCI. Jacopo Andrea Oreglia reviews the typical complications seen in practice, and shares his experiences on how to manage them.
Complications in CTO-PCI can be both cardiac and non-cardiac, and prompt recognition is key to managing them without major sequelae.
Common cardiac complications are coronary perforation or rupture, donor vessel injury, collateral channel ischaemia, and loss or entrapment of devices. Of these, coronary rupture or perforation is one of the most feared. Rupture of the vessel wall happens most frequently during pre-dilatation, stent deployment, or post-dilatation, while collateral rupture or distal vessel perforation may be caused by wire or microcatheter injury. Any rupture or perforation may lead to rapid haemodynamic collapse due to cardiac tamponade. Treatment should always begin with a rapid balloon inflation proximally, or at the level of the perforation or rupture, to block bleeding. Specific methods, such as the dual catheter technique or the block-and-deliver technique must be used to resolve the issue. A covered stent is usually needed to treat significant lateral vessel rupture, and detachable coils are necessary to treat distal vessel or collateral perforations. Reversal of anticoagulation (that is, protamine) should be avoided until the guiding catheter, guidewires, or other equipment are in the coronary vessels. If cardiac tamponade occurs, pericardiocentesis must be performed, and IV fluids and vasopressors administered.
Although coronary perforations are most dreaded, ischaemic complications, especially within the donor vessel, may be catastrophic. When planning a retrograde CTO-PCI, particular attention should be paid to the donor vessel anatomy and any possible disease. Even intermediate lesions can cause significant ischaemia when a guidewire and a microcatheter are advanced across them. Injury to the donor vessel may be dramatic, since a vast area of myocardium is jeopardised, and profound ischaemia with hypotension, ECG changes, arrhythmias, or shock may occur. Anticoagulation control must be checked regularly to avoid donor vessel thrombosis, and a systematic final control angiogram of the donor vessel should be performed before the guidewire is removed from the retrograde system to assess integrity of the collateral circulation, and to rule out possible donor vessel dissections. Also consider treatment of intermediate lesions in the donor vessel, in case a retrograde approach is planned.
Equipment entrapment or loss is another possible complication, and can happen especially in heavily calcific lesions or tortuous vessels. Guidewires may get damaged and stuck and/or break in the lesion or artery. Balloons, stents, or more often, rotablator burrs, may lodge in the vessel and specific techniques have to be used to remove them.
Most complications can be managed by the interventional cardiologist in the cath-lab, but in rare situations surgical treatment may be necessary. CTO PCI requires a systematic and disciplined approach. It is a complex procedure, and an awareness of the different steps to be performed is necessary to keep the procedure as safe as possible. Being prepared to deal with any complications that can arise is part of the planning process for CTO-PCI.
If a complication occurs, prompt recognition is key in order to avoid major sequelae. Flow-charts simplify and standardise problem-solving techniques to help achieve good outcomes for the patient. Operators should gain confidence in the use of devices such as covered stents, detachable coils, snaring systems, and so on, and understand the compatibility of coils with different microcatheters. Equipment that could be useful to treat a complication (pericardiocentesis tray, coils, covered stents, microcatheters, etc.) should be stored in a special area so that cath-lab staff can access it very quickly.
Complications are rare, but prompt and effective treatment is mandatory; interventional cardiologists should share their experiences and allow others to learn the techniques, tips, and tricks involved, even if they have not yet experienced it for themselves.
Jacopo Andrea Oreglia is head of the interventional cardiology unit at De Gasperis Cardio Center, Niguarda Hospital, Milan, Italy