Coronary laser with simultaneous contrast injection for the treatment of stent underexpansion

Abstract

Background: Stent underexpansion is a challenge in interventional cardiology. Some off-label treatments, such as rotational atherectomy, intravascular lithotripsy (IVL) and coronary lasing, have been used to overcome the problem. The purpose of this study is to evaluate the safety and efficacy of coronary laser atherectomy with simultaneous contrast injection and subsequent balloon dilation to optimize stent expansion.

Methods: Coronary laser atherectomy with simultaneous contrast injection was used. After lasing, non-compliant balloon dilation at high pressure was performed to overcome the underexpanded point. The average increase in the minimum stent area (MSA) was measured by intravascular ultrasound (IVUS), and any complication related to the technique was evaluated. Additionally, major adverse cardiovascular events (MACE), consisting of death from any cause, new myocardial infarction (MI) and target lesion revascularization (TLR), were scrutinized in a long-term follow-up.

Results: Sixteen underexpanded stents were treated with laser between August 2017 and November 2022. In all cases but one, IVUS was used to evaluate the MSA before and after lasing. The MSA showed an average increase of 2.34 ± 1.57 mm² (95% confidence interval [CI]: 1.47-3.21; p < 0.001) after laser application and balloon inflation. No complication related to the technique was detected. During a follow-up period of a median (interquartile range) of 457 (50-973) days, the combined MACE assessed by Kaplan-Meier estimator showed an event-free rate of 0.82 (95% CI: 0.59-1).

Conclusions: Coronary laser with simultaneous contrast injection is a safe method to optimize a stent underexpansion, with an acceptable event-free rate in long-term follow-up.

Keywords: ELCA; PCI; excimer laser coronary angioplasty; percutaneous coronary intervention.

Figure 1

Koninklijke Philips N.V. (San Diego, CA, USA) CVX-300 excimer laser coronary atherectomy system with its monorail catheter.

Figure 2

Kaplan-Meier estimator illustrating the event-free rate of the combined major adverse cardiovascular events including death from any cause, new myocardial infarction and target lesion revascularization during a median (interquartile range) follow-up of 457 (50–973) days; CI — confidence interval.

Figure 3

An 87-year-old woman admitted to the documented center due to non-ST-segment elevation myocardial infarction underwent a coronary angiogram. A severe calcified stenosis of the left anterior descending coronary artery (LAD) proximal segment was appreciated during the coronary angiogram, although the injection provoked left main (LM) dissection, which spread antegradely as well as retrogradely to the sinus of Valsalva and ascending aorta (A). Any additional injection was avoided, and in order to seal the dissection, the operator decided to implant a direct 3.5 × 16 mm drug eluting stent (DES) in LM-LAD after verifying the correct positioning of the guidewire into the true lumen by intravascular ultrasound (IVUS). However, an important underexpansion in the distal part of the stent was detected (B). Dilation with a non-compliant 3.5 × 12 mm balloon could not overcome the underexpanded point (C), and an intravascular lithotripsy (IVL) balloon was unable to cross the lesion. The IVUS probe did not cross the tight point either. Excimer laser coronary atherectomy 0.9 mm with a fluency and frequency of 45 mJ/mm² and 25 Hz, respectively, and simultaneous contrast injection was used. Afterward, the same non-compliant balloon overcame the stent underexpansion (D). The proximal and mid segment of the LAD was significantly diseased, so the procedure was completed by applying a cutting balloon and IVL and implanting a second DES, overlapped with the previous one. A successful angiographic result was achieved with a complete sealing of the dissection at the level of the sinus of Valsalva (E), and the patient had an uneventful hospital stay.

Figure 4

On bench study of laser interaction with saline and contrast milieu. While the saline milieu avoids microbubble formation (A), laser interaction with contrast creates a large number of microbubbles (B).

Figure 5

Stent underexpansion circled by a calcified ring (A). After laser ablation with simultaneous contrast injection and balloon dilatation the minimum stent area improved significantly (B).