PCI complications: vessel perforation

# Overview
Coronary perforations are uncommon (<1%) complications of percutaneous coronary intervention (PCI) and are associated with significant morbidity and mortality rates. Coronary perforations are infrequent in patients undergoing balloon angioplasty (0.1%) compared with patients undergoing atheroablative therapy (1.3%; p<0.001). Perforation due to coronary guidewires may present late after the procedure.

# Classification
Coronary artery perforation has been classified by Ellis et al. based on its angiographic appearance:

## Ellis Type II Perforation

## Ellis Type III Perforation

# Risk Factors

## PCI Equipment
- The use of stiff guidewires, hydrophilic guidewires and guidewires in which the core extends to the tip of the guidewire are associated with perforation.

## PCI Technique
- Balloon to artery ratio > 1.1
- Over expansion of a stent at high pressures
- Use of debulking procedure such as rotational atherectomy

## Lesion Risk Factors
Complex coronary anatomy including:
- Chronic total occlusions
- Calcified lesions
- Tortuous vessels

# Natural History, Complications and Prognosis

## Complications
Complications of vessel perforation include cardiac tamponade, myocardial infarction (MI) and death. It is important to maintain hemodynamic stability. Should tamponade occur, it is important to detect and treat it immediately.
Hemodynamic assessment with right heart pressure monitoring should be considered with particular attention being paid to a sudden rise in right atrial filling pressures. Also, it is important to monitor heart borders on fluoroscopy to detect signs of tamponade, as signified by a lack of movement of the heart borders.
Urgent echocardiography should be performed to evaluate for the presence of pericardial effusion and tamponade physiology. Immediate notification of the cardiothoracic surgical team is important so as to facilitate drainage of an effusion and urgent surgery to close the perforation if needed.

## Prognosis
The prognosis based upon the Ellis Classification is as follows:
- Type I - No deaths or myocardial infarction, tamponade incidence 8%
- Type II - No deaths, myocardial infarction incidence 14%, tamponade incidence 13%
- Type III - Mortality incidence 19%, cardiac tamponade incidence 63%, the need for urgent bypass surgery 63%
- Type III "cavity spilling" (CS) - No deaths, myocardial infarction or tamponade, but sample limited in size

# Diagnosis
Perforation is an angiographic diagnosis. It appears as a small extraluminal extravasation of blush in the distribution of the target vessel. Care should be taken to routinely visualize the distal extent of the vessel following PCI to exclude the presence of a wire perforation. Emergency echocardiography should be performed to rule out the presence of a pericardial effusion or pericardial tamponade.

# Treatment
Initial management strategies include:

## Reversal of Anticoagulation
One is the initial steps is to reverse the anticoagulation. This includes the administration of protamine to reverse heparin. Protamine will also partially reverse the antithrombotic effect of enoxaparin if this antithrombin was used. Administration of platelets can be considered if abciximab has been administered. If it is greater than four hours after a maintenance dose of prasugrel or greater than six hours after a loading dose of prasugrel, then a platelet infusion should also be considered.

## Prolonged Balloon Inflation
Inflations up to 20 minutes may be needed to achieve hemostasis. For this reason it is often wise for a cardiac catheterization laboratory to have perfusion balloons in a range of sizes available.

## Covered Stent
In refractory cases, polytetrafluoroethylene covered stents (stent grafts) can be used to seal the perforation. They can be used for most coronary perforations, but small, excessively angulated or tortuous vessels may not be amenable to them.

## Other Techniques
Other techniques include coil embolization, the injection of clotted blood, the use of gel foam and the injection of thrombin at the site of the perforation. Coil embolization is suitable for small side branch perforations, but it will lead to tissue infarction and may not be available in all catheterization laboratories. Coil embolization is suited for small vessels, distal locations, arteries that supply limited viable myocardium, or situations where surgery is contraindicated.

## Surgery
Approximately one third of cases of PCI-associated coronary artery perforation require emergent cardiac surgery. Surgical closure is necessary for perforations that demonstrate continued bleeding despite minimal invasive therapy, refractory ischemia, or recurrent hemorrhage. Incomplete closure is signified by persistent dye extravasation, while pericardial fluid collection and impending cardiac tamponade is signified by increasing right atrial pressure. Peristent fluid accumulation or pericardial drain output (>24 h) should prompt surgical repair.

## Echocardiographic Monitoring
Serial echocardiography should be performed q 6-12h to detect the presence of an expanding pericardial effusion or cardiac tamponade physiology.