The contemporary use of intracoronary brachytherapy for instent restenosis: A review

In-stent restenosis (ISR) has been a major limitation in interventional cardiology and constitutes nearly 10 % of all percutaneous coronary interventions in the United States. Drug-eluting stent (DES) restenosis proves particularly difficult to manage and poses a high risk of recurrence and repeat intervention. Intra-coronary brachytherapy (IBT) has been traditionally viewed as a potential treatment modality for ISR. However, its use was hindered by procedural complexity, cost, and the advent of newer-generation DES. Recent data suggests promising results regarding IBT for the treatment of resistant DES-ISR. This review addresses the mechanism of action of IBT, procedural details, and associated risks and complications of its use. It will also highlight the available clinical evidence supporting the use of IBT and the future directions of its utilization in the treatment of ISR.

[Invasive and non-invasive imaging analysis for calcified coronary artery lesions]

Coronary calcifications are frequently identified within coronary lesions as their incidence increases with age and cardiovascular risk factors. Their location can be superficial or deep, according to different pathological process. In all cases, the presence of calcifications within the vascular wall predicts poor clinical prognosis and unfavorable evolution after percutaneous revascularization. Coronary calcifications can be analyzed by angiography, CT or intracoronary imaging (IVUS or OCT) with variable accuracies. Angiography is the most frequently used method but is not very sensitive (sensitivity close to 50%) and insufficient for their precise quantification. The CT scan is a more effective non-invasive method leading to an accurate analysis of the lesion before coronary angiography. IVUS and OCT have an excellent spatial resolution and are the most sensitive methods for the identification (present in nearly 75-80% of lesions) and quantification of calcifications. These intracoronary imaging techniques offer interesting perspectives for identification of the highest-risk lesions, PCI procedures planning (including the choice of an optimal dedicated plaque preparation devices), the monitoring of their execution and the evaluation of the immediate post-stenting results.

Intra-coronary Imaging for the Evaluation of Plaque Modifications Induced by Drug Therapies for Secondary Prevention

PURPOSE OF REVIEW

Patients diagnosed with coronary artery disease are at a high risk of subsequent cardiovascular events; therefore, secondary prevention in the form of therapeutic lifestyle changes, and drug therapies is vital. This article aims to review potential application of intra-coronary imaging for the evaluation of plaque modifications, induced by medications for secondary prevention for CAD.

RECENT FINDINGS

Intra-coronary imaging provides detailed information on the atherosclerotic plaque which is the primary pathological substrate for the recurrent ischemic cardiovascular events. These modalities can detect features associated with high risk and allow serial in vivo imaging of lesions. Therefore, intravascular imaging tools have been used in landmark studies and played a role in improving our understanding of the disease processes. Changes in size and plaque composition over time can be evaluated by these tools and may help understanding the impact of a treatment. Moreover, surrogate imaging end points can be used when testing new drugs for secondary prevention.

Utility of Imaging Modalities in Coronary Lesions With Borderline Fractional Flow Reserve

BACKGROUND

Coronary intervention is routinely deferred in intermediate lesions with fractional flow reserve (FFR) ≥ 0.80. Patients with borderline FFR (0.80-0.85) who were initially deferred, have been shown to have higher risk of future interventions; however, the data is limited, and the long term prognosis in these patients remains unknown. We assessed the utility of adjunctive imaging modalities to determine the need for intervention in lesions with borderline FFR.

METHODS

We retrospectively evaluated consecutive patients who underwent coronary angiography at Einstein Medical Center from January 2013 to April 2016. All patients with borderline FFR (0.80-0.85) were included. Patients were divided into Defer or Perform intervention groups based on additional available or procured clinical data. The Perform group was further stratified into intervention With or Without adjunctive imaging guidance (including intravascular ultrasound, optical coherence tomography, echocardiography, and exercise or pharmacologic stress test). Follow-up data was collected for all patients, which included future target lesion revascularization (TLR) and major adverse cardiac events (MACE; all-cause and cardiovascular mortality and acute coronary syndromes).

RESULTS

A total of 196 patients were eligible. Median (IQR) FFR in Perform and Defer groups was 0.81 (0.8-0.83) and 0.84 (0.82-0.85) respectively. Median (IQR) follow up was 21 (13-29) and 25 (15-36) months respectively. Overall MACE rate in Perform group (n = 101) was 20.8% (n = 21) and Defer group (n = 95) was 15.8% (n = 15). The stratified MACE rate in Perform group With imaging guidance (n = 57) was 17.5% (n = 10) and Without imaging guidance (n = 44) was 25% (n = 11). Overall, the FFR only guided management (n = 196) led to MACE rate of 18.4% (n = 36); whereas, FFR With imaging guidance (n = 136) led to MACE rate of 16.2% (n = 22). The p values were non-significant in each of the above group comparisons due to relatively low numbers with trends as noted.

CONCLUSIONS

Our study suggests that intervention of coronary lesions with borderline FFR under imaging guidance, although not significant, trends towards improved cardiovascular outcomes compared with intervention in this group without adjunctive imaging. These findings are merely speculative without achieving statistical significance in a small subset and need to be further validated in a large scale prospective study.