Visualization of collateral channels with coronary computed tomography angiography for the retrograde approach in percutaneous coronary intervention for chronic total occlusion.

BACKGROUND: There have been no reports about the diagnostic ability of coronary computed tomography angiography (CTA) in evaluating collateral channels used for retrograde chronic total occlusion (CTO) percutaneous coronary intervention (PCI). OBJECTIVE: We investigated the ability and diagnostic accuracy of coronary CTA compared with invasive coronary angiography to detect collaterals used in retrograde CTO PCI and to compared the success rates for wire crossing between collaterals that are detectable and not detectable in coronary CTA. METHODS: We retrospectively reviewed data from 43 patients (55 collaterals) who underwent coronary CTA and PCI for CTO with the retrograde approach. We compared the ability of coronary CTA to visualize collaterals to invasive coronary angiography and evaluated the rates of successful wire crossing between CTA-visible and invisible collaterals. RESULTS: The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of coronary CTA for detecting collaterals which were used for the retrograde approach was 100.0%, 50.0%, 65.9%, 100.0%, and 74.5%, respectively. Guidewire collateral crossing was more successful in CT-visible collaterals than those not detectable in CT (74.1% vs. 46.4%, p = 0.034). There were fewer collateral vessel injuries in CTA-visible collaterals (11.1% vs. 32.1%, p = 0.041). CONCLUSION: Coronary CTA provides good visualization of collaterals used in retrograde CTO PCI. For retrograde guidewire crossing, a higher success rate with fewer complications was observed in CTA-visible collaterals than in those not detectable in coronary CTA.

The latest wire technique for chronic total occlusion.

If patency is restored after chronic total occlusion (CTO), it can be maintained over the long term by implanting drug-eluting stents. The cause of unsuccessful percutaneous coronary intervention is usually failure of the wire to cross the site of CTO. The objective of this article is to describe the latest wire techniques for CTO. As for wire selection, CTO should generally be treated with hard-tipped spring wires, preferably Conquest Pro series (Asahi Intec). According to the penetrating strategy, the course of a blood vessel with CTO is established preoperatively and the wire is advanced based on the imaging data with minimum rotation (a torque of +/- 90 degrees or less). If the operator encounters divergence between the preoperative CTO image and the actual course of the coronary artery, the parallel wire technique should be used. With this method, a wire which enters the subintimal space is left there, and a second wire is inserted along it to find a new channel. When this technique is successful, the following findings are often noted: 1) the second wire crosses over the first one in the CTO; 2) the second wire shows more acute curve than the first wire; 3) the second wire penetrates the lesion from the outer curvature of the coronary artery and then is advanced along the same curvature of the vessel. Indeed, the second wire should be operated intentionally to achieve these findings so that the probability of success increases and the duration of the procedure is shortened.

[Acute coronary syndrome due to coronary thrombus formed by severe coronary spasm: a case report].

A 47-year-old man was admitted to our hospital complaining of chest pain at rest in the early morning. Electrocardiography showed ST segment elevation in leads II, III and aVF. Emergency coronary angiography revealed total occlusion of the right coronary artery at the proximal portion. Intracoronary administration of isosorbide dinitrate successfully recanalized the right coronary artery. However, there was a thrombus image at the culprit lesion. Intracoronary administration of urokinase caused the residual thrombus to disappear completely. Follow-up coronary angiography at 1 week and 3 months revealed no organic stenotic lesion. Intravascular ultrasound showed only a little plaque without signs of ruptured plaque in the right coronary artery. Provocation coronary angiography revealed remarkable spasm causing total occlusion at the proximal portion of the right coronary artery. This case suggests that only severe coronary spasm without plaque rupture could form a thrombus causing acute coronary syndrome.