Clinicians have long recognized that certain features of coronary artery lesions increase the complexity of intervention. Complex lesions are associated with worse cardiovascular outcomes and a higher risk of subsequent ischemic events. These lesions are categorized by their angiographic features. These features include bifurcation lesions, left main coronary artery disease, calcified lesions, in-stent restenosis, chronic total occlusions and graft interventions. This two-part review aims to highlight the current evidence in the percutaneous management of these lesions. Part one of this review focuses on the best techniques to treat bifurcation lesions, indications for intervention of left main coronary artery disease and additional tools used to treat calcified lesions.

Calcified coronary plaque (CCP) represents a challenging scenario for interventional cardiologists. Stent underexpansion (SU), often associated with CCP, can predispose to stent thrombosis and in-stent restenosis. To date, SU with heavily CCP can be addressed using very high-/high-pressure noncompliant balloons, off-label rotational atherectomy/orbital atherectomy, excimer laser atherectomy, and intravascular lithotripsy (IVL). In this meta-analysis, we investigated the success rate of IVL for the treatment of SU because of CCP. Studies and case-based experiences reporting on the use of IVL strategy for treatment of SU were included. The primary end point was IVL strategy success, defined as the adequate expansion of the underexpanded stent. A metanalysis was performed for the main focuses to calculate the proportions of procedural success rates with corresponding 95% confidence intervals (CIs). Random-effects models weighted by inverse variance were used because of clinical heterogeneity. This meta-analysis included 13 studies with 354 patients. The mean age was 71.3 years (95% CI 64.9 to 73.1), and 77% (95% CI 71.2% to 82.4%) were male. The mean follow-up time was 2.6 months (95% CI 1 to 15.3). Strategy success was seen in 88.7% (95% CI 82.3 to 95.1) of patients. The mean minimal stent area was reported in 6 studies, the pre-IVL value was 3.4 mm2 (95% CI 3 to 3.8), and the post-IVL value was 6.9 mm2 (95% CI 6.5 to 7.4). The mean diameter stenosis (percentage) was reported in 7 studies, the pre-IVL value was 69.4% (95% CI 60.7 to 78.2), and the post-IVL value was 14.6% (95% CI 11.1 to 18). The rate of intraprocedural complications was 1.6% (95% CI 0.3 to 2.9). In conclusion, the \"stent-through\" IVL plaque modification technique is a safe tool to treat SU caused by CCP, with a high success rate and a very low incidence of complications.

Soft-tissue calcifications in the head and neck are relatively common and are the result of a wide variety of benign and malignant pathologies. They can present a diagnostic challenge given the broad range of underlying etiologies. Uremic tumoral calcinosis (UTC) is a rare complication of end-stage renal disease (ESRD) resulting from metastatic soft tissue calcification. Common sites include periarticular soft tissues of the shoulders, elbows, and hands (Pan and Chen, 2016). UTC can also affect the cervical spine and mimic osteosarcomas (Zhou et al., 2018). We present the case of a 71-year-old female with hypertension, left carotid artery stenosis, mitral valve prolapse, and ESRD secondary to diabetes mellitus type II (DMII) on peritoneal dialysis who was found to have large, heterogeneous, bilateral calcified neck masses. Given her clinical history, laboratory results, and imaging findings, she was diagnosed with UTC. In addition to this case, we provide an overview of tumoral calcinosis (TC) and a differential diagnosis for calcified lesions of the head and neck.

Coronary artery calcification is prevalent in coronary heart disease with its progression being predictive of future adverse cardiac events. Its presence is considered to be a marker of interventional procedural complexity. Several adjunctive percutaneous coronary intervention tools, such as modifying balloons, atherectomy devices and intravascular lithotripsy, now exist to successfully treat calcified lesions. In this state-of-the-art review, a step-wise progression of strategies is described to modify coronary plaque, from well-recognised techniques to techniques that should only be considered when standard manoeuvres have proven unsuccessful. Technology has advanced greatly over the past few decades and we discuss how future technologies might shape percutaneous intervention.