Intravascular lithotripsy during percutaneous coronary intervention for calcified coronary lesions: analysis of patient and procedural characteristics and clinical outcomes

Funding Acknowledgements

Type of funding sources: None.

Background/Introduction

Coronary artery calcification is frequently encountered during percutaneous coronary intervention (PCI). It can reduce PCI success and increase intra-procedural and post-procedural complications, including stent embolization, under-expansion and mal-apposition. Intravascular lithotripsy (IVL) is a new tool developed to treat calcified coronary lesions.

Purpose

Retrospective analysis of all cases of intravascular lithotripsy performed within our local health district to examine patient and procedural characteristics and clinical outcomes.

Methods

All patients undergoing PCI with intravascular lithotripsy between September 2019-August 2021 within our local health district were analysed. Patient and procedural characteristics and clinical outcomes were recorded.

Results

67 patients (50 men) were included with mean age 71.4 ± 8.7years. Risk factors prevalence included smoking (34%), hypertension (82%), dyslipidaemia (69%) and diabetes (46%). Trans-radial artery access was used in 38 patients (57%). IVL was performed most commonly in the left anterior descending artery (52%),[Figure 1]. IVL was utilised in 9 chronic total occlusions and 12 bifurcation lesions. Intracoronary (IC) imaging was performed in 59 patients (88%), intravascular ultrasound in 41(61%) and optical coherence tomography in 18 (27%). 41 (69%) patients had imaging performed pre and post IVL and post PCI.  IC imaging identified 14 cases with 270º calcification arc and 45 cases with 360º arc. Nine cases (13.4%) required rotational atherectomy prior to IVL (most commonly 1.75mm burr). Mean reference vessel diameter was 3.2 ± 0.3mm. Mean lesion length was 36.3 ± 16.5mm. Mean pre-PCI stenosis was 85.5 ± 10.8%. Drug eluting stents were successfully deployed in 57 cases (85%), 10 had balloon angioplasty alone. Mean stent length was 39.2 ± 17.8mm. Mean post-PCI stenosis was 4.5 ± 13.3% (median 0%). Figure 2 shows a statistically significant increase in minimum lumen diameter and minimum lumen area post-IVL and minimal-stent-area (MSA) post-PCI. Mean stent expansion was 83%. Mean screening time 35.8 ± 17.8 minutes with mean contrast used 207.3 ± 78.7mL. No sustained arrhythmias or side-branch loss occurred. Vessel rupture was recorded in one patient necessitating urgent cardiac surgery (due to oversized balloon) and in 4 cases the IVL balloon could not cross the lesion.

Conclusion

Our experience shows that IVL is safe and effective and facilitates stent delivery and expansion. Intracoronary imaging is important to determine the need for calcium modification and evaluate its success prior to stent delivery and to confirm optimised stent expansion. Abstract Figure. Breakdown of PCI Artery  Abstract Figure. IC Dimensions Pre/Post IVL/Post PCI

P2717Type-II MI and chronic myocardial injury rates, invasive management and 4 year mortality among consecutive patients undergoing high sensitivity troponin T testing in the emergency department

Background

In emergency departments (EDs), assessment of patients with suspected acute coronary syndromes (ACS) represents a major workload and high sensitivity troponin (HsTn) T and I levels are frequently measured. A minority of patients have final diagnosis of myocardial infarction (MI).

Methods and results

Among 2738 consecutive patients with suspected ACS presenting to ED at Liverpool Hospital, Australia, between March and June 2014, we determined the relative frequencies of 3 patient groups: type-I MI, type-II MI including chronic myocardial injury (CMI), and assessed the use of invasive and pharmacological therapies and 4-year outcomes. Adjudication of MI was according to the 4th universal definition of MI as follows: 1) type-I MI; 2) type-II MI (including acute myocardial injury), and 3) CMI. Of 995 patients (36%) median age 76 years [IQR 65–83]), with at least 2 HsTnT measurements and one >14ng/l, 727 (73%) had chronic myocardial injury, 171 (17%) had type-II MI; and 97 (9.7%) had type-I MI. Patients with type-I MI (mean age 63 years) were younger than those with type-II MI or chronic myocardial injury by 12 and 14 years respectively. The main triggering factors for type-II MI/acute injury included: sepsis (21.1%), acute heart failure (18.3%), tachyarrhythmia (16.9%), anaemia (8.6%) and a combination of factors (16%). In-hospital angiography (62% had PCI) rates were 95% for patients with type-I MI, 24% (7% PCI) for those with type-II MI and 3.4% for CMI. Mortality at 4 years was 55% for type-II MI, 44% for CMI and 18% for type-1 MI (P<0.001; Figure), though after Cox modelling adjusting for age, gender, renal function and COPD, compared to type 1 MI, type-II MI (hazard ratio 1.61 [95% CIs 0.90–2.86]; p=0.106) and CMI (hazard ratio 1.01 [95% CIs 0.59–1.74]; p=0.963) were not independently associated with increased late mortality, largely because patients with type 1 MI were a decade younger.

Conclusion

Among unselected patients undergoing HsTnT testing in EDs, type-II MI including acute myocardial injury was more common than type-I MI. Chronic myocardial injury, which occurred in 3 of 4 patients. While patients with type-II MI acute myocardial injury had higher late mortality rates than type-I MI, though after multivariable analyses mortality rates were not different.