Primary Angioplasty of Calcified Coronary Lesions Using Coronary Lithotripsy in Acute ST-Segment Elevation Myocardial Infarction

Background. This study reports procedural and short-term clinical outcomes from a real-world series with the use of coronary lithotripsy in the context of primary angioplasty in ST-segment elevation myocardial infarction (STEMI). Methods and Results. This was a prospective registry conducted at 2 hospitals, which included 10 patients who presented a culprit calcified lesion within acute STEMI and underwent coronary lithotripsy during primary angioplasty, between July 2019 and July 2020. Mean age was 69.2 ± 11.8 years, and there was a high proportion of hypertension (70%) and dyslipidemia (60%). All lesions (type B/C) were predilated with a semicompliant balloon. Coronary lithotripsy was performed in all cases once macroscopic thrombus was successfully retrieved by thrombus aspiration catheter. Before lithotripsy, rotational atherectomy was used in 1 case and cutting balloon was used in 2 cases. On average, coronary lithotripsy required the use of 1 lithotripsy balloon (range, 1-2) delivering a mean of 70 pulses. Two lithotripsy balloons were ruptured during lithotripsy therapy without any adverse event. Successful coronary lithotripsy was achieved in 90%. There were no periprocedural cardiac complications. Conclusions. Coronary lithotripsy seems to be a safe and effective technique in patients with STEMI and a culprit calcified lesion undergoing primary angioplasty for calcium modification in the absence of angiographic thrombus, and a suitable option to achieve adequate stent expansion and apposition.

J INVASIVE CARDIOL 2021;33(12):E970-E973. Epub 2021 November 11.

Key words: atherectomy, calcification

Coronary calcification increases percutaneous coronary intervention (PCI) complexity. It may impair stent delivery and affect suitable stent expansion and apposition, which increases the risk of stent thrombosis and restenosis.¹ The prevalence of patients with ST-segment elevation myocardial infarction (STEMI) and a culprit calcified coronary lesion is growing due to population aging, chronic kidney disease, and diabetes.^1,2 Coronary lithotripsy (CL) works by fracturing the calcified plaque, thus allowing mean area gain and facilitating stent expansion and apposition.^1,2 Despite successful early results in real-world multicenter registries, there is scarce evidence about the use of CL in STEMI patients.³ This study reports procedural and short-term clinical outcomes from a real-world series with the use of CL in the context of primary angioplasty in STEMI.

Between July 2019 and July 2020, a total of 10 patients who presented a culprit severe calcified coronary lesion within acute STEMI and subsequently underwent CL during primary angioplasty were included in this registry, which was conducted at 2 hospitals. Baseline and procedural characteristics as well as events at 30-day follow-up are listed in Table 1. Mean age was 69.2 ± 11.8 years and there was a high proportion of hypertension (70%) and dyslipidemia (60%). Only 1 patient had previously undergone PCI. Five patients had multivessel disease. The most frequently treated artery was the left anterior descending coronary artery (50%). Thrombolysis in Myocardial Infarction (TIMI) flow grade was 0 in 8 patients. Thrombus aspiration was performed when angiographic thrombus was observed after guidewire passage. All lesions, which were stratified as type B (70%) or type C (30%) according to the American College of Cardiology/American Heart Association classification system, were predilated with a semicompliant balloon. All 10 lesions showed severe calcification by angiography. Intravascular imaging techniques were performed in 5 lesions, showing severe concentric calcium distribution.

The Coronary Rx Lithoplasty System (Shockwave Medical) was used in all cases once macroscopic thrombus was successfully retrieved by thrombus aspiration catheter. CL success was defined as achieving <50% of residual diameter stenosis of the target lesion and successful deployment of the stent. Before CL, other plaque-modification techniques were performed (rotational atherectomy in 1 case and cutting balloon in 2 cases). In 3 lesions, a guide-catheter extension was used to place the lithotripsy balloon at the level of the lesion due to severe proximal tortuosity. CL was performed with the use of 1 lithotripsy balloon (range, 1-2 balloons), delivering a mean of 70 pulses. Two lithotripsy balloons were ruptured during lithotripsy therapy without any adverse event; the mean number of cycles before rupture was 3.5 (range, 2-5 cycles).

Successful CL was achieved in 90% of cases. A representative case is shown in Figure 1.There was only 1 case of an eccentric calcified coronary lesion in which we could not achieve <50% of the residual diameter stenosis of the target lesion despite the use of a non-compliant balloon, cutting balloon, and 2 lithotripsy balloons (16 therapies applied). For that reason, the patient was treated with a drug-eluting balloon; the patient remained asymptomatic at 1-year follow-up. The average number of stents per lesion was 1.5 (range, 1-2 stents), with a mean stent diameter of 3.1 ± 0.8 mm and a mean stent length of 30.6 ± 12.1 mm. There were no periprocedural cardiac complications. During the hospital stay, 1 elderly patient who presented with STEMI in the postoperative period of lower-limb amputation due to severe peripheral vascular disease experienced a stroke 4 days later. Despite mechanical thrombectomy; the patient died 5 days later.

In patients with STEMI, PCI may be challenging due to the presence of a culprit calcified coronary lesion. Coronary lithotripsy has been shown to be a safe and effective technique for coronary calcium modification.^1,2 This is a real-world series of patients with STEMI and a culprit calcified coronary lesion undergoing CL during primary angioplasty. The main findings of the registry are: (1) there was no procedural complications; (2) the lithotripsy balloon seems to be a safe and effective tool in patients with STEMI and a culprit calcified coronary lesion for calcium modification in the absence of angiographic thrombus; and (3) the concomitant use of other plaque-modification devices may be useful in these complex cases to achieve procedural success.

This registry shows that in the presence of a culprit calcified coronary lesion within acute STEMI and undergoing primary angioplasty, the use of coronary lithotripsy seems to be a feasible, safe, and suitable option to achieve adequate stent expansion and apposition. Larger multicenter registries are required to clarify the role of CL and other plaque-modification techniques within STEMI.

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